Neuroscience

Articles and news from the latest research reports.

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Legal high Benzo Fury may be dangerous due to stimulant and hallucinogenic effects
The ‘legal high’ known as Benzo Fury may have stimulant as well as hallucinogenic effects according to new research presented at the British Neuroscience Association Festival of Neuroscience today (Tuesday 9 April 2013).
In a poster presentation at the meeting, Dr Jolanta Opacka-Juffry and Dr Colin Davidson reported that one of the main ingredients of Benzo Fury (also known as 5-APB) acts on brain tissue like both a stimulant and a hallucinogen – a combination of properties that is often found in illegal drugs and which can make them dangerous to users. The researchers believe this information should be disseminated to let potential users know the possible dangers of the drug.
Dr Opacka-Juffry, who is a principal lecturer in neuroscience and director of the health sciences research centre at the University of Roehampton, and Dr Davidson, senior lecturer in neuropharmacology and expert in drugs of addiction at St George’s, University of London, studied the effect of 5-APB samples from the brains of rats. In particular, they looked at the effect it had on serotonin receptors, which are affected by hallucinogenic drugs, and on a protein called the dopamine transporter (DAT), which pumps a neurotransmitter, dopamine, back in to nerve cells, terminating its activity, and which is involved in addiction. They compared the effects of 5-APB with those caused by cocaine and amphetamine.
“We have found that 5-APB behaves a little like amphetamine – that is, like a stimulant with addictive potential – and a bit like a hallucinogen, acting via serotonin receptors. This kind of mixed properties can be found in some illegal ‘designer’ drugs,” the presenting author, Dr Opacka-Juffry said.
“This finding is significant because it demonstrates that some ‘legal highs’ may have addictive properties, which are unlikely to be well-known amongst the users of these drugs. In addition, its effects on the serotonin receptors – known as 5-HT2A receptors – would suggest that it may lead to high blood pressure by causing constriction of the blood vessels, which would make the drug more dangerous. It is possible that the reason these drugs are so popular is because they are seen as safer than their illegal counterparts. It is important to challenge these assumptions.”
The researchers also found that 5-APB caused “reverse transport of dopamine”.
Dr Davidson said: “In theory, drugs which cause reverse transport could cause damage to the dopamine nerve cells. Other drugs such as amphetamines can also cause reverse transport, where dopamine is displaced from the nerve rather than mopped up by the dopamine transporter.”
Dr Opacka-Juffry said: “It is in the combination of these stimulant and hallucinogenic properties that the greatest danger lies. Pure hallucinogens are not addictive as such because they do not cause an increase in dopamine release, unlike amphetamine or cocaine. They are attractive to many people who enjoy the ‘mind altering’ properties of hallucinogens. But Benzo Fury with its mixed properties is a trap as its repetitive use for the hallucinogenic effects could lead to dependence, which the user may not expect.”
Further work needs to be carried out to find out more. “Rat data are quite informative as the brain addiction pathway is similar in rodents and humans. Long-term effects should be tested in rodents to investigate the potential toxic effects on the nervous system and the cardiovascular system, in addition to its liability for abuse due to addiction. We also need to collate data from human users. Taken together we can determine how dangerous this drug is,” she said.
Benzo Fury is currently one of the most popular legal highs in the UK and is also sold in the USA. It appears to be fairly easy to buy via the internet, at music festivals and clubs, and its street price is around £10 a pill or £25 for three. “However, tragedies such as the death of 19-year-old Alex Heriot at a music festival in June 2012 after taking Benzo Fury demonstrate the importance of making as much information available as possible about the potential adverse effects of these ‘highs’ as quickly as possible,” said Dr Opacka-Juffry.
Drs Opacka-Juffry and Davidson report that the approach they used to study Benzo Fury could be applied to other drugs as well, so that as new legal high drugs emerge, they can be tested quickly against the “gold standard” drugs such as cocaine and amphetamines to establish their relative danger.
Dr Davidson said: ”Over the last few years 40 or more new legal highs have appeared each year. Given the speed with which legal highs are developed and reach the market, it is important to be able to respond quickly to assess their potential dangers, and disseminate this information accordingly.”

Legal high Benzo Fury may be dangerous due to stimulant and hallucinogenic effects

The ‘legal high’ known as Benzo Fury may have stimulant as well as hallucinogenic effects according to new research presented at the British Neuroscience Association Festival of Neuroscience today (Tuesday 9 April 2013).

In a poster presentation at the meeting, Dr Jolanta Opacka-Juffry and Dr Colin Davidson reported that one of the main ingredients of Benzo Fury (also known as 5-APB) acts on brain tissue like both a stimulant and a hallucinogen – a combination of properties that is often found in illegal drugs and which can make them dangerous to users. The researchers believe this information should be disseminated to let potential users know the possible dangers of the drug.

Dr Opacka-Juffry, who is a principal lecturer in neuroscience and director of the health sciences research centre at the University of Roehampton, and Dr Davidson, senior lecturer in neuropharmacology and expert in drugs of addiction at St George’s, University of London, studied the effect of 5-APB samples from the brains of rats. In particular, they looked at the effect it had on serotonin receptors, which are affected by hallucinogenic drugs, and on a protein called the dopamine transporter (DAT), which pumps a neurotransmitter, dopamine, back in to nerve cells, terminating its activity, and which is involved in addiction. They compared the effects of 5-APB with those caused by cocaine and amphetamine.

“We have found that 5-APB behaves a little like amphetamine – that is, like a stimulant with addictive potential – and a bit like a hallucinogen, acting via serotonin receptors. This kind of mixed properties can be found in some illegal ‘designer’ drugs,” the presenting author, Dr Opacka-Juffry said.

“This finding is significant because it demonstrates that some ‘legal highs’ may have addictive properties, which are unlikely to be well-known amongst the users of these drugs. In addition, its effects on the serotonin receptors – known as 5-HT2A receptors – would suggest that it may lead to high blood pressure by causing constriction of the blood vessels, which would make the drug more dangerous. It is possible that the reason these drugs are so popular is because they are seen as safer than their illegal counterparts. It is important to challenge these assumptions.”

The researchers also found that 5-APB caused “reverse transport of dopamine”.

Dr Davidson said: “In theory, drugs which cause reverse transport could cause damage to the dopamine nerve cells. Other drugs such as amphetamines can also cause reverse transport, where dopamine is displaced from the nerve rather than mopped up by the dopamine transporter.”

Dr Opacka-Juffry said: “It is in the combination of these stimulant and hallucinogenic properties that the greatest danger lies. Pure hallucinogens are not addictive as such because they do not cause an increase in dopamine release, unlike amphetamine or cocaine. They are attractive to many people who enjoy the ‘mind altering’ properties of hallucinogens. But Benzo Fury with its mixed properties is a trap as its repetitive use for the hallucinogenic effects could lead to dependence, which the user may not expect.”

Further work needs to be carried out to find out more. “Rat data are quite informative as the brain addiction pathway is similar in rodents and humans. Long-term effects should be tested in rodents to investigate the potential toxic effects on the nervous system and the cardiovascular system, in addition to its liability for abuse due to addiction. We also need to collate data from human users. Taken together we can determine how dangerous this drug is,” she said.

Benzo Fury is currently one of the most popular legal highs in the UK and is also sold in the USA. It appears to be fairly easy to buy via the internet, at music festivals and clubs, and its street price is around £10 a pill or £25 for three. “However, tragedies such as the death of 19-year-old Alex Heriot at a music festival in June 2012 after taking Benzo Fury demonstrate the importance of making as much information available as possible about the potential adverse effects of these ‘highs’ as quickly as possible,” said Dr Opacka-Juffry.

Drs Opacka-Juffry and Davidson report that the approach they used to study Benzo Fury could be applied to other drugs as well, so that as new legal high drugs emerge, they can be tested quickly against the “gold standarddrugs such as cocaine and amphetamines to establish their relative danger.

Dr Davidson said: ”Over the last few years 40 or more new legal highs have appeared each year. Given the speed with which legal highs are developed and reach the market, it is important to be able to respond quickly to assess their potential dangers, and disseminate this information accordingly.”

Filed under hallucinogenic drugs BNA2013 benzo fury brain tissue nerve cells neuroscience science

38 notes

Researchers create next-generation Alzheimer’s disease model
A new genetically engineered lab rat that has the full array of brain changes associated with Alzheimer’s disease supports the idea that increases in a molecule called beta-amyloid in the brain causes the disease, according to a study, published in the Journal of Neuroscience. The study was supported by the National Institutes of Health.
"We believe the rats will be an excellent, stringent pre-clinical model for testing experimental Alzheimer’s disease therapeutics,” said Terrence Town, Ph.D., the study’s senior author and a professor in the Department of Physiology & Biophysics in the Zilkha Neurogenetic Institute at the University of Southern California Keck School of Medicine, Los Angeles.
Alzheimer’s is an age-related brain disorder that gradually destroys a person’s memory, thinking, and the ability to carry out even the simplest tasks. Affecting at least 5.1 million Americans, the disease is the most common form of dementia in the United States. Pathological hallmarks of Alzheimer’s brains include abnormal levels of beta-amyloid protein that form amyloid plaques; tau proteins that clump together inside neurons and form neurofibrillary tangles; and neuron loss.  
Additionally, glial cells—which normally support, protect, or nourish nerve cells—are overactivated in Alzheimer’s.
Plaque-forming beta-amyloid molecules are derived from a larger protein called amyloid precursor protein (APP). One hypothesis states that increases in beta-amyloid initiate brain degeneration. Genetic studies on familial forms of Alzheimer’s support the hypothesis by linking the disease to mutations in APP, and to presenilin 1, a protein thought to be involved in the production beta-amyloid.
Researchers often use rodents to study diseases. However, previous studies on transgenic mice and rats that have the APP and presenilin 1 mutations only partially reproduce the problems caused by Alzheimer’s. The animals have memory problems and many plaques but none of the other hallmarks, especially neurofibrillary tangles and neuron loss.
To address this issue, Dr. Town and his colleagues decided to work with a certain strain of rats.
“We focused on Fischer 344 rats because their brains develop many of the age-related features seen in humans,” said Dr. Town, who conducted the study while working as a professor of Biomedical Sciences at Cedars-Sinai Medical Center and David Geffen School of Medicine at the University of California, Los Angeles.
The rats were engineered to have the mutant APP and presenilin 1 genes, which are known to play a role in the rare, early-onset form of Alzheimer’s. Behavioral studies showed that the rats developed memory and learning problems with age. As predicted, the presence of beta-amyloid in the brains of the rats increased with age. However, unlike previous rodent studies, the rats also developed neurofibrillary tangles.
“This new rat model more closely represents the brain changes that take place in humans with Alzheimer’s, including tau pathology and extensive neuronal cell death,” said Roderick Corriveau, Ph.D., a program director at NIH’s National Institute of Neurological Disorders and Stroke. “The model will help advance our understanding of the various disease pathways involved in Alzheimer’s onset and progression and assist us in testing promising interventions.”
The researchers performed a variety of experiments confirming the presence of neurofibrillary tangles in brain regions most affected by Alzheimer’s such as the hippocampus and the cingulate cortex, which are involved in learning and memory. Further experiments showed that about 30 percent of neurons in these regions died with age, the largest amount of cell death seen in an Alzheimer’s rodent model, and that some glial cells acquired shapes reminiscent of the activated glia found in patients.
“Our results suggest that beta-amyloid can drive Alzheimer’s in a clear and progressive way,” said Dr. Town.
Activation of glia occurred earlier than amyloid plaque formation, which suggests Dr. Town and his colleagues identified an early degenerative event and new treatment target that scientists studying other rodent models may have missed.
The findings support a prime research objective identified during the May 2012, NIH-supported Alzheimer’s Disease Research Summit 2012: Path to Treatment and Prevention, an international gathering of Alzheimer’s researchers and advocates. Improved animal models were cited as key to advancing understanding of this complex disease.
"To fully benefit from this exciting new work, there is a critical need to share the animal model with researchers dedicated to finding ways to delay, prevent or treat Alzheimer’s disease’’ said Neil Buckholtz, Ph.D., of the National Institute on Aging, which leads the NIH effort in Alzheimer’s research. “Accordingly, Dr. Town and his colleagues are working towards making their new rat model easily accessible to the research community.”

Researchers create next-generation Alzheimer’s disease model

A new genetically engineered lab rat that has the full array of brain changes associated with Alzheimer’s disease supports the idea that increases in a molecule called beta-amyloid in the brain causes the disease, according to a study, published in the Journal of Neuroscience. The study was supported by the National Institutes of Health.

"We believe the rats will be an excellent, stringent pre-clinical model for testing experimental Alzheimer’s disease therapeutics,” said Terrence Town, Ph.D., the study’s senior author and a professor in the Department of Physiology & Biophysics in the Zilkha Neurogenetic Institute at the University of Southern California Keck School of Medicine, Los Angeles.

Alzheimer’s is an age-related brain disorder that gradually destroys a person’s memory, thinking, and the ability to carry out even the simplest tasks. Affecting at least 5.1 million Americans, the disease is the most common form of dementia in the United States. Pathological hallmarks of Alzheimer’s brains include abnormal levels of beta-amyloid protein that form amyloid plaques; tau proteins that clump together inside neurons and form neurofibrillary tangles; and neuron loss.  

Additionally, glial cells—which normally support, protect, or nourish nerve cells—are overactivated in Alzheimer’s.

Plaque-forming beta-amyloid molecules are derived from a larger protein called amyloid precursor protein (APP). One hypothesis states that increases in beta-amyloid initiate brain degeneration. Genetic studies on familial forms of Alzheimer’s support the hypothesis by linking the disease to mutations in APP, and to presenilin 1, a protein thought to be involved in the production beta-amyloid.

Researchers often use rodents to study diseases. However, previous studies on transgenic mice and rats that have the APP and presenilin 1 mutations only partially reproduce the problems caused by Alzheimer’s. The animals have memory problems and many plaques but none of the other hallmarks, especially neurofibrillary tangles and neuron loss.

To address this issue, Dr. Town and his colleagues decided to work with a certain strain of rats.

“We focused on Fischer 344 rats because their brains develop many of the age-related features seen in humans,” said Dr. Town, who conducted the study while working as a professor of Biomedical Sciences at Cedars-Sinai Medical Center and David Geffen School of Medicine at the University of California, Los Angeles.

The rats were engineered to have the mutant APP and presenilin 1 genes, which are known to play a role in the rare, early-onset form of Alzheimer’s. Behavioral studies showed that the rats developed memory and learning problems with age. As predicted, the presence of beta-amyloid in the brains of the rats increased with age. However, unlike previous rodent studies, the rats also developed neurofibrillary tangles.

“This new rat model more closely represents the brain changes that take place in humans with Alzheimer’s, including tau pathology and extensive neuronal cell death,” said Roderick Corriveau, Ph.D., a program director at NIH’s National Institute of Neurological Disorders and Stroke. “The model will help advance our understanding of the various disease pathways involved in Alzheimer’s onset and progression and assist us in testing promising interventions.”

The researchers performed a variety of experiments confirming the presence of neurofibrillary tangles in brain regions most affected by Alzheimer’s such as the hippocampus and the cingulate cortex, which are involved in learning and memory. Further experiments showed that about 30 percent of neurons in these regions died with age, the largest amount of cell death seen in an Alzheimer’s rodent model, and that some glial cells acquired shapes reminiscent of the activated glia found in patients.

“Our results suggest that beta-amyloid can drive Alzheimer’s in a clear and progressive way,” said Dr. Town.

Activation of glia occurred earlier than amyloid plaque formation, which suggests Dr. Town and his colleagues identified an early degenerative event and new treatment target that scientists studying other rodent models may have missed.

The findings support a prime research objective identified during the May 2012, NIH-supported Alzheimer’s Disease Research Summit 2012: Path to Treatment and Prevention, an international gathering of Alzheimer’s researchers and advocates. Improved animal models were cited as key to advancing understanding of this complex disease.

"To fully benefit from this exciting new work, there is a critical need to share the animal model with researchers dedicated to finding ways to delay, prevent or treat Alzheimer’s disease’’ said Neil Buckholtz, Ph.D., of the National Institute on Aging, which leads the NIH effort in Alzheimer’s research. “Accordingly, Dr. Town and his colleagues are working towards making their new rat model easily accessible to the research community.”

Filed under alzheimer's disease beta amyloid amyloid plaques tau proteins amyloid precursor protein animal model neuroscience science

376 notes

Remarkable Success In Patients With Major Depression
For the first time, physicians from the Bonn University Hospital have stimulated patients’ medial forebrain bundles.
Researchers from the Bonn University Hospital implanted pacemaker electrodes into the medial forebrain bundle in the brains of patients suffering from major depression with amazing results: In six out of seven patients, symptoms improved both considerably and rapidly. The method of Deep Brain Stimulation had already been tested on various structures within the brain, but with clearly lesser effect. The results of this new study have now been published in the renowned international journal “Biological Psychiatry.”
After months of deep sadness, a first smile appears on a patient’s face. For many years, she had suffered from major depression and tried to end her life several times. She had spent the past years mostly in a passive state on her couch; even watching TV was too much effort for her. Now this young woman has found her joie de vivre again, enjoys laughing and traveling. She and an additional six patients with treatment resistant depression participated in a study involving a novel method for addressing major depression at the Bonn University Hospital.
Considerable amelioration of depression within days
Prof. Dr. Volker Arnd Coenen, neurosurgeon at the Department of Neurosurgery (Klinik und Poliklinik für Neurochirurgie), implanted electrodes into the medial forebrain bundles in the brains of subjects suffering from major depression with the electrodes being connected to a brain pacemaker. The nerve cells were then stimulated by means of a weak electrical current, a method called Deep Brain Stimulation. In a matter of days, in six out of seven patients, symptoms such as anxiety, despondence, listlessness and joylessness had improved considerably. “Such sensational success both in terms of the strength of the effects, as well as the speed of the response has so far not been achieved with any other method,” says Prof. Dr. Thomas E. Schläpfer from the Bonn University Hospital Department of Psychiatry und Psychotherapy (Bonner Uniklinik für Psychiatrie und Psychotherapie).
Central part of the reward circuit
The medial forebrain bundle is a bundle of nerve fibers running from the deep-seated limbic system to the prefrontal cortex. In a certain place, the bundle is particularly narrow because the individual nerve fibers lie close together. “This is exactly the location in which we can have maximum effect using a minimum of current,” explains Prof. Coenen, who is now the new head of the Freiburg University Hospital’s Department of Stereotactic and Functional Neurosurgery (Abteilung Stereotaktische und Funktionelle Neurochirurgie am Universitätsklinikum Freiburg). The medial forebrain bundle is a central part of a euphoria circuit belonging to the brain’s reward system. What kind of effect stimulation exactly has on nerve cells is not yet known. But it obviously changes metabolic activity in the different brain centers.
Success clearly increased over that of earlier studies
The researchers have already shown in several studies that deep brain stimulation shows an amazing and–given the severity of the symptoms– unexpected degree of amelioration of symptoms in major depression. In those studies, however, the physicians had not implanted the electrodes into the medial forebrain bundle but instead into the nucleus accumbens, another part of the brain’s reward system. This had resulted in clear and sustainable improvements in about 50 percent of subjects. “But in this new study, our results were even much better,” says Prof. Schläpfer. A clear improvement in complaints was found in 85 percent of patients, instead of the earlier 50 percent. In addition, stimulation was performed with lower current levels, and the effects showed within a few days, instead of after weeks.
Method’s long-term success proven
“Obviously, we have now come closer to a critical structure within the brain that is responsible for major depression,” says the psychiatrist from the Bonn University Hospital. Another cause for optimism among the group of physicians is that, since the study’s completion, an eighth patient has also been treated successfully. The patients have been observed for a period of up to 18 month after the intervention. Prof. Schläpfer reports, “The anti-depressive effect of deep brain stimulation within the medial forebrain bundle has not decreased during this period.” This clearly indicates that the effects are not temporary. This method gives those who suffer from major depression reason to hope. However, it will take quite a bit of time for the new procedure to become part of standard therapy.

Remarkable Success In Patients With Major Depression

For the first time, physicians from the Bonn University Hospital have stimulated patients’ medial forebrain bundles.

Researchers from the Bonn University Hospital implanted pacemaker electrodes into the medial forebrain bundle in the brains of patients suffering from major depression with amazing results: In six out of seven patients, symptoms improved both considerably and rapidly. The method of Deep Brain Stimulation had already been tested on various structures within the brain, but with clearly lesser effect. The results of this new study have now been published in the renowned international journal “Biological Psychiatry.”

After months of deep sadness, a first smile appears on a patient’s face. For many years, she had suffered from major depression and tried to end her life several times. She had spent the past years mostly in a passive state on her couch; even watching TV was too much effort for her. Now this young woman has found her joie de vivre again, enjoys laughing and traveling. She and an additional six patients with treatment resistant depression participated in a study involving a novel method for addressing major depression at the Bonn University Hospital.

Considerable amelioration of depression within days

Prof. Dr. Volker Arnd Coenen, neurosurgeon at the Department of Neurosurgery (Klinik und Poliklinik für Neurochirurgie), implanted electrodes into the medial forebrain bundles in the brains of subjects suffering from major depression with the electrodes being connected to a brain pacemaker. The nerve cells were then stimulated by means of a weak electrical current, a method called Deep Brain Stimulation. In a matter of days, in six out of seven patients, symptoms such as anxiety, despondence, listlessness and joylessness had improved considerably. “Such sensational success both in terms of the strength of the effects, as well as the speed of the response has so far not been achieved with any other method,” says Prof. Dr. Thomas E. Schläpfer from the Bonn University Hospital Department of Psychiatry und Psychotherapy (Bonner Uniklinik für Psychiatrie und Psychotherapie).

Central part of the reward circuit

The medial forebrain bundle is a bundle of nerve fibers running from the deep-seated limbic system to the prefrontal cortex. In a certain place, the bundle is particularly narrow because the individual nerve fibers lie close together. “This is exactly the location in which we can have maximum effect using a minimum of current,” explains Prof. Coenen, who is now the new head of the Freiburg University Hospital’s Department of Stereotactic and Functional Neurosurgery (Abteilung Stereotaktische und Funktionelle Neurochirurgie am Universitätsklinikum Freiburg). The medial forebrain bundle is a central part of a euphoria circuit belonging to the brain’s reward system. What kind of effect stimulation exactly has on nerve cells is not yet known. But it obviously changes metabolic activity in the different brain centers.

Success clearly increased over that of earlier studies

The researchers have already shown in several studies that deep brain stimulation shows an amazing and–given the severity of the symptoms– unexpected degree of amelioration of symptoms in major depression. In those studies, however, the physicians had not implanted the electrodes into the medial forebrain bundle but instead into the nucleus accumbens, another part of the brain’s reward system. This had resulted in clear and sustainable improvements in about 50 percent of subjects. “But in this new study, our results were even much better,” says Prof. Schläpfer. A clear improvement in complaints was found in 85 percent of patients, instead of the earlier 50 percent. In addition, stimulation was performed with lower current levels, and the effects showed within a few days, instead of after weeks.

Method’s long-term success proven

“Obviously, we have now come closer to a critical structure within the brain that is responsible for major depression,” says the psychiatrist from the Bonn University Hospital. Another cause for optimism among the group of physicians is that, since the study’s completion, an eighth patient has also been treated successfully. The patients have been observed for a period of up to 18 month after the intervention. Prof. Schläpfer reports, “The anti-depressive effect of deep brain stimulation within the medial forebrain bundle has not decreased during this period.” This clearly indicates that the effects are not temporary. This method gives those who suffer from major depression reason to hope. However, it will take quite a bit of time for the new procedure to become part of standard therapy.

Filed under deep brain stimulation medial forebrain bundle depression nerve cells prefrontal cortex neuroscience science

61 notes

Producing new neurones under all circumstances: a challenge that is just a mouse away …
Improving neurone production in elderly persons presenting with a decline in cognition is a major challenge facing an ageing society and the emergence of neuro-degenerative conditions such as Alzheimer’s disease. INSERM and CEA researchers recently showed that the pharmacological blocking of the TGFβ molecule improves the production of new neurones in the mouse model. These results incentivise the development of targeted therapies enabling improved neurone production to alleviate cognitive decline in the elderly and reduce the cerebral lesions caused by radiotherapy.
The research is published in the journal EMBO Molecular Medicine. 
New neurones are formed regularly in the adult brain in order to guarantee that all our cognitive capacities are maintained. This neurogenesis may be adversely affected in various situations and especially:
- in the course of ageing, - after radiotherapy treatment of a brain tumour. (The irradiation of certain areas of the brain is, in fact, a central adjunctive therapy for brain tumours in adults and children).
According to certain studies, the reduction in our “stock” of neurones contributes to an irreversible decline in cognition. In the mouse, for example, researchers reported that exposing the brain to radiation in the order of 15 Gy is accompanied by disruption to the olfactive memory and a reduction in neurogenesis. The same happens in ageing in which a reduction in neurogenesis is associated with a loss of certain cognitive faculties. In patients receiving radiotherapy due to the removal of a brain tumour, the same phenomena can be observed.
Researchers are studying how to preserve the “neurone stock”. To do this, they have tried to discover which factors are responsible for the decline in neurogenesis.
Contrary to what might have been believed, their initial observations show that neither heavy doses of radiation nor ageing are responsible for the complete disappearance of the neural stem cells capable of producing neurones (and thus the origin of neurogenesis). Those that survive remain localised in a certain small area of the brain (the sub-ventricular zone (SVZ)). They nevertheless appear not to be capable of working correctly.
Additional experiments have made it possible to establish that in both situations, irradiation and ageing, high levels of the cytokine TGFβ cause the stem cells to become dormant, increasing their susceptibility to apoptosis (PCD) and reducing the number of new neurones.
“Our study concluded that although neurogenesis reduced in ageing and after a high dose of radiation, many stem cells survive for several months, retaining their ‘stem’ characteristics”, explains Marc-Andre Mouthon, one of the main authors of the research, that was conducted in conjunction with José Piñeda and François Boussin.
The second part of the project demonstrated that pharmacological blocking of TGFβ restores the production of new neurones in irradiated or ageing mice.
For the researchers, these results will encourage the development of targeted therapies to block TGFβ in order to reduce the impact of brain lesions caused by radiotherapy and improving the production of neurones in the elderly presenting with a cognitive decline.

Producing new neurones under all circumstances: a challenge that is just a mouse away …

Improving neurone production in elderly persons presenting with a decline in cognition is a major challenge facing an ageing society and the emergence of neuro-degenerative conditions such as Alzheimer’s disease. INSERM and CEA researchers recently showed that the pharmacological blocking of the TGFβ molecule improves the production of new neurones in the mouse model. These results incentivise the development of targeted therapies enabling improved neurone production to alleviate cognitive decline in the elderly and reduce the cerebral lesions caused by radiotherapy.

The research is published in the journal EMBO Molecular Medicine.

New neurones are formed regularly in the adult brain in order to guarantee that all our cognitive capacities are maintained. This neurogenesis may be adversely affected in various situations and especially:

- in the course of ageing,
- after radiotherapy treatment of a brain tumour. (The irradiation of certain areas of the brain is, in fact, a central adjunctive therapy for brain tumours in adults and children).

According to certain studies, the reduction in our “stock” of neurones contributes to an irreversible decline in cognition. In the mouse, for example, researchers reported that exposing the brain to radiation in the order of 15 Gy is accompanied by disruption to the olfactive memory and a reduction in neurogenesis. The same happens in ageing in which a reduction in neurogenesis is associated with a loss of certain cognitive faculties. In patients receiving radiotherapy due to the removal of a brain tumour, the same phenomena can be observed.

Researchers are studying how to preserve the “neurone stock”. To do this, they have tried to discover which factors are responsible for the decline in neurogenesis.

Contrary to what might have been believed, their initial observations show that neither heavy doses of radiation nor ageing are responsible for the complete disappearance of the neural stem cells capable of producing neurones (and thus the origin of neurogenesis). Those that survive remain localised in a certain small area of the brain (the sub-ventricular zone (SVZ)). They nevertheless appear not to be capable of working correctly.

Additional experiments have made it possible to establish that in both situations, irradiation and ageing, high levels of the cytokine TGFβ cause the stem cells to become dormant, increasing their susceptibility to apoptosis (PCD) and reducing the number of new neurones.

“Our study concluded that although neurogenesis reduced in ageing and after a high dose of radiation, many stem cells survive for several months, retaining their ‘stem’ characteristics”, explains Marc-Andre Mouthon, one of the main authors of the research, that was conducted in conjunction with José Piñeda and François Boussin.

The second part of the project demonstrated that pharmacological blocking of TGFβ restores the production of new neurones in irradiated or ageing mice.

For the researchers, these results will encourage the development of targeted therapies to block TGFβ in order to reduce the impact of brain lesions caused by radiotherapy and improving the production of neurones in the elderly presenting with a cognitive decline.

Filed under brain neurons cognitive decline neurogenesis aging radiotherapy neuroscience science

117 notes

Month of birth impacts on immune system development

Newborn babies’ immune system development and levels of vitamin D have been found to vary according to their month of birth, according to new research.

image

The research, from scientists at Queen Mary, University of London and the University of Oxford, provides a potential biological basis as to why an individual’s risk of developing the neurological condition multiple sclerosis (MS) is influenced by their month of birth. It also supports the need for further research into the potential benefits of vitamin D supplementation during pregnancy.

Around 100,000 people in the UK have MS, a disabling neurological condition which results from the body’s own immune system damaging the central nervous system. This interferes with the transmission of messages between the brain and other parts of the body and leads to problems with vision, muscle control, hearing and memory. 

The development of MS is believed to be a result of a complex interaction between genes and the environment.

A number of population studies have suggested that the month you are born in can influence your risk of developing MS. This ‘month of birth’ effect is particularly evident in England, where the risk of MS peaks in individuals born in May and drops in those delivered in November. As vitamin D is formed by the skin when it is exposed to sunlight, the ‘month of birth’ effect has been interpreted as evidence of a prenatal role for vitamin D in MS risk.

In this study, samples of cord blood – blood extracted from a newborn baby’s umbilical cord – were taken from 50 babies born in November and 50 born in May between 2009 and 2010 in London.

The blood was analysed to measure levels of vitamin D and levels of autoreactive T-cells. T-cells are white blood cells which play a crucial role in the body’s immune response by identifying and destroying infectious agents, such as viruses. However some T-cells are ‘autoreactive’ and capable of attacking the body’s own cells, triggering autoimmune diseases, and should be eliminated by the immune system during its development. This job of processing T-cells is carried out by the thymus , a specialised organ in the immune system located in the upper chest cavity.

The results showed that the May babies had significantly lower levels of vitamin D (around 20 per cent lower than those born in November) and significantly higher levels (approximately double) of these autoreactive T-cells, compared to the sample of November babies.

Co-author Dr Sreeram Ramagopalan, a lecturer in neuroscience at Barts and The London School of Medicine and Dentistry, part of Queen Mary, said: “By showing that month of birth has a measurable impact on in utero immune system development, this study provides a potential biological explanation for the widely observed “month of birth” effect in MS. Higher levels of autoreactive T-cells, which have the ability to turn on the body, could explain why babies born in May are at a higher risk of developing MS.

“The correlation with vitamin D suggests this could be the driver of this effect. There is a need for long-term studies to assess the effect of vitamin D supplementation in pregnant women and the subsequent impact on immune system development and risk of MS and other autoimmune diseases.”

The research letter is published today in the journal JAMA Neurology.

(Source: qmul.ac.uk)

Filed under infants immune system autoimmune diseases CNS MS vitamin d neuroscience science

217 notes

Reframing Stress: Stage Fright Can Be Your Friend
Fear of public speaking tops death and spiders as the nation’s number one phobia. But new research shows that learning to rethink the way we view our shaky hands, pounding heart, and sweaty palms can help people perform better both mentally and physically.
Before a stressful speaking task, simply encouraging people to reframe the meaning of these signs of stress as natural and helpful was a surprisingly effective way of handling stage fright, found the study to be published online April 8 in Clinical Psychological Science. 
"The problem is that we think all stress is bad," explains Jeremy Jamieson, the lead author on the study and an assistant professor of psychology at the University of Rochester. "We see headlines about ‘Killer Stress’ and talk about being ‘stressed out.’" Before speaking in public, people often interpret stress sensations, like butterflies in the stomach, as a warning that something bad is about to happen, he says.
"But those feelings just mean that our body is preparing to address a demanding situation," explains Jamieson. "The body is marshaling resources, pumping more blood to our major muscle groups and delivering more oxygen to our brains." Our body’s reaction to social stress is the same flight or fight response we produce when confronting physical danger. These physiological responses help us perform, whether we’re facing a bear in the forest or a critical audience.
For many people, especially those suffering from social anxiety disorder, the natural uneasiness experienced before giving a speech can quickly tip over into panic. “If we think we can’t cope with stress, we will experience threat. When threatened, the body enacts changes to concentrate blood in the core and restricts flow to the arms, legs, and brain,” he explains. So, “cold feet” is a real physiological response to threat, not just a colorful expression.
"Lots of current advice for anxious people focuses on learning to ‘relax,’—you know, deep, even breathing and similar tips," says Jamieson. Such calming techniques, write the authors, may be helpful in situations that do not require peak performance. But when gearing up for a high-stakes exam, a job interview, or, yes, a speaking engagement, reframing how we think about stress may be a better strategy.
Then how can people reap the benefits of being stressed without being overwhelmed by dread? To answer that question, Jamieson and co-authors Matthew Nock, of Harvard University and Wendy Berry Mendes of the University of California in San Francisco, turned to the Trier Social Stress Test. Developed in 1993 by Clemens Kirschbaum and colleagues, this experiment relies on fear of public speaking and has become one of the most reliable laboratory methods for eliciting threat responses.
In the study, 69 adults were asked to give a five-minute talk about their strengths and weaknesses with only three minutes to prepare. Roughly half of the participants had a history of social anxiety and all participants were randomly assigned to two groups. The first group was presented information about the advantages of the body’s stress response and encouraged to “reinterpret your bodily signals during the upcoming public speaking task as beneficial.” That group also was asked to read summaries of three psychology studies that showed the benefits of stress. The second group received no information about reframing stress.
Participants delivered their speech to two judges. On purpose, the judges provided negative nonverbal feedback throughout the entire five-minute presentations, shaking their heads in disapproval, tapping on their clipboards, and staring stone-faced ahead. If study subjects ran out of things to say, the judges insisted that they continue speaking for the full five minutes. Following the speech, participants were asked to count backwards for five minutes in steps of seven beginning with the number 996. The evaluators again provided negative feedback throughout and insisted that participants start over if they made any mistakes.
Confronted with scowling judges, participants who received no stress preparation experienced a threat response, as captured by cardiovascular measures. But the group that was prepped about the benefits of stress weathered the trial better. That group reported feeling that they had more resources to cope with the public speaking task and, perhaps more tellingly, their physiological responses confirmed those perceptions. The prepped group pumped more blood through the body per minute compared to the group that did not receive instruction.
Surprisingly, this study also found that individuals who suffer from social anxiety disorder actually experienced no greater increase in physiological arousal while under scrutiny than their non-anxious counterparts, despite reporting more intense feelings of apprehension. This disconnect, argue the authors, supports the theory that our experience of acute or short-term stress is shaped by how we interpret physical cues. “We construct our own emotions,” says Jamieson.

Reframing Stress: Stage Fright Can Be Your Friend

Fear of public speaking tops death and spiders as the nation’s number one phobia. But new research shows that learning to rethink the way we view our shaky hands, pounding heart, and sweaty palms can help people perform better both mentally and physically.

Before a stressful speaking task, simply encouraging people to reframe the meaning of these signs of stress as natural and helpful was a surprisingly effective way of handling stage fright, found the study to be published online April 8 in Clinical Psychological Science.

"The problem is that we think all stress is bad," explains Jeremy Jamieson, the lead author on the study and an assistant professor of psychology at the University of Rochester. "We see headlines about ‘Killer Stress’ and talk about being ‘stressed out.’" Before speaking in public, people often interpret stress sensations, like butterflies in the stomach, as a warning that something bad is about to happen, he says.

"But those feelings just mean that our body is preparing to address a demanding situation," explains Jamieson. "The body is marshaling resources, pumping more blood to our major muscle groups and delivering more oxygen to our brains." Our body’s reaction to social stress is the same flight or fight response we produce when confronting physical danger. These physiological responses help us perform, whether we’re facing a bear in the forest or a critical audience.

For many people, especially those suffering from social anxiety disorder, the natural uneasiness experienced before giving a speech can quickly tip over into panic. “If we think we can’t cope with stress, we will experience threat. When threatened, the body enacts changes to concentrate blood in the core and restricts flow to the arms, legs, and brain,” he explains. So, “cold feet” is a real physiological response to threat, not just a colorful expression.

"Lots of current advice for anxious people focuses on learning to ‘relax,’—you know, deep, even breathing and similar tips," says Jamieson. Such calming techniques, write the authors, may be helpful in situations that do not require peak performance. But when gearing up for a high-stakes exam, a job interview, or, yes, a speaking engagement, reframing how we think about stress may be a better strategy.

Then how can people reap the benefits of being stressed without being overwhelmed by dread? To answer that question, Jamieson and co-authors Matthew Nock, of Harvard University and Wendy Berry Mendes of the University of California in San Francisco, turned to the Trier Social Stress Test. Developed in 1993 by Clemens Kirschbaum and colleagues, this experiment relies on fear of public speaking and has become one of the most reliable laboratory methods for eliciting threat responses.

In the study, 69 adults were asked to give a five-minute talk about their strengths and weaknesses with only three minutes to prepare. Roughly half of the participants had a history of social anxiety and all participants were randomly assigned to two groups. The first group was presented information about the advantages of the body’s stress response and encouraged to “reinterpret your bodily signals during the upcoming public speaking task as beneficial.” That group also was asked to read summaries of three psychology studies that showed the benefits of stress. The second group received no information about reframing stress.

Participants delivered their speech to two judges. On purpose, the judges provided negative nonverbal feedback throughout the entire five-minute presentations, shaking their heads in disapproval, tapping on their clipboards, and staring stone-faced ahead. If study subjects ran out of things to say, the judges insisted that they continue speaking for the full five minutes. Following the speech, participants were asked to count backwards for five minutes in steps of seven beginning with the number 996. The evaluators again provided negative feedback throughout and insisted that participants start over if they made any mistakes.

Confronted with scowling judges, participants who received no stress preparation experienced a threat response, as captured by cardiovascular measures. But the group that was prepped about the benefits of stress weathered the trial better. That group reported feeling that they had more resources to cope with the public speaking task and, perhaps more tellingly, their physiological responses confirmed those perceptions. The prepped group pumped more blood through the body per minute compared to the group that did not receive instruction.

Surprisingly, this study also found that individuals who suffer from social anxiety disorder actually experienced no greater increase in physiological arousal while under scrutiny than their non-anxious counterparts, despite reporting more intense feelings of apprehension. This disconnect, argue the authors, supports the theory that our experience of acute or short-term stress is shaped by how we interpret physical cues. “We construct our own emotions,” says Jamieson.

Filed under stress stress sensations public speaking anxiety psychology neuroscience science

98 notes

Rare primate’s vocal lip-smacks share features of human speech
The vocal lip-smacks that geladas use in friendly encounters have surprising similarities to human speech, according to a study reported in the Cell Press journal Current Biology on April 8th. The geladas, which live only in the remote mountains of Ethiopia, are the only nonhuman primate known to communicate with such a speech-like, undulating rhythm. Calls of other monkeys and apes are typically one or two syllables and lack those rapid fluctuations in pitch and volume.
This new evidence lends support to the idea that lip-smacking, a behavior that many primates show during amiable interactions, could have been an evolutionary step toward human speech.
"Our finding provides support for the lip-smacking origins of speech because it shows that this evolutionary pathway is at least plausible," said Thore Bergman of the University of Michigan in Ann Arbor. "It demonstrates that nonhuman primates can vocalize while lip-smacking to produce speech-like sounds."
Bergman first began to wonder about the geladas’ sounds when he began his fieldwork in 2006. “I would find myself frequently looking over my shoulder to see who was talking to me, but it was just the geladas,” he recalled. “It was unnerving to have primate vocalizations sound so much like human voices.”
That was something that he had never experienced in the company of other primates. Then Bergman came across a paper in Current Biology last year proposing vocalization while lip-smacking as a possible first step to human speech, and something clicked.
Bergman has now analyzed recordings of the geladas’ vocalizations, known as “wobbles,” to find a rhythm that closely matches human speech. In other words, because they vocalize while lip-smacking, the pattern of sound produced is structurally similar to human speech.
In both lip-smacking and speech, the rhythm corresponds to the opening and closing of parts of the mouth. What’s more, Bergman said, lip-smacking might serve the same purpose as language in many basic human interactions—think of how friends bond through small talk.
"Language is not just a great tool for exchanging information; it has a social function," Bergman said. "Many verbal exchanges appear to serve a function similar to lip-smacking."

Rare primate’s vocal lip-smacks share features of human speech

The vocal lip-smacks that geladas use in friendly encounters have surprising similarities to human speech, according to a study reported in the Cell Press journal Current Biology on April 8th. The geladas, which live only in the remote mountains of Ethiopia, are the only nonhuman primate known to communicate with such a speech-like, undulating rhythm. Calls of other monkeys and apes are typically one or two syllables and lack those rapid fluctuations in pitch and volume.

This new evidence lends support to the idea that lip-smacking, a behavior that many primates show during amiable interactions, could have been an evolutionary step toward human speech.

"Our finding provides support for the lip-smacking origins of speech because it shows that this evolutionary pathway is at least plausible," said Thore Bergman of the University of Michigan in Ann Arbor. "It demonstrates that nonhuman primates can vocalize while lip-smacking to produce speech-like sounds."

Bergman first began to wonder about the geladas’ sounds when he began his fieldwork in 2006. “I would find myself frequently looking over my shoulder to see who was talking to me, but it was just the geladas,” he recalled. “It was unnerving to have primate vocalizations sound so much like human voices.”

That was something that he had never experienced in the company of other primates. Then Bergman came across a paper in Current Biology last year proposing vocalization while lip-smacking as a possible first step to human speech, and something clicked.

Bergman has now analyzed recordings of the geladas’ vocalizations, known as “wobbles,” to find a rhythm that closely matches human speech. In other words, because they vocalize while lip-smacking, the pattern of sound produced is structurally similar to human speech.

In both lip-smacking and speech, the rhythm corresponds to the opening and closing of parts of the mouth. What’s more, Bergman said, lip-smacking might serve the same purpose as language in many basic human interactions—think of how friends bond through small talk.

"Language is not just a great tool for exchanging information; it has a social function," Bergman said. "Many verbal exchanges appear to serve a function similar to lip-smacking."

Filed under primates geladas communication speech vocalization neuroscience science

100 notes

Couch Potatoes May Be Genetically Predisposed to Being Lazy
Studies show 97 percent of American adults get less than 30 minutes of exercise a day, which is the minimum recommended amount based on federal guidelines. New research from the University of Missouri suggests certain genetic traits may predispose people to being more or less motivated to exercise and remain active. Frank Booth, a professor in the MU College of Veterinary Medicine, along with his post-doctoral fellow Michael Roberts, were able to selectively breed rats that exhibited traits of either extreme activity or extreme laziness. They say these rats indicate that genetics could play a role in exercise motivation, even in humans.
“We have shown that it is possible to be genetically predisposed to being lazy,” Booth said. “This could be an important step in identifying additional causes for obesity in humans, especially considering dramatic increases in childhood obesity in the United States. It would be very useful to know if a person is genetically predisposed to having a lack of motivation to exercise, because that could potentially make them more likely to grow obese.”
In their study published in the American Journal of Physiology: Regulatory, Integrative and Comparative Physiology on April 3, 2013, Roberts and Booth put rats in cages with running wheels and measured how much each rat willingly ran on their wheels during a six-day period. They then bred the top 26 runners with each other and bred the 26 rats that ran the least with each other. They repeated this process through 10 generations and found that the line of running rats chose to run 10 times more than the line of “lazy” rats.
Once the researchers created their “super runner” and “couch potato” rats, they studied the levels of mitochondria in muscle cells, compared body composition and conducted thorough genetic evaluations through RNA deep sequencing of each rat.
“While we found minor differences in the body composition and levels of mitochondria in muscle cells of the rats, the most important thing we identified were the genetic differences between the two lines of rats,” Roberts said. “Out of more than 17,000 different genes in one part of the brain, we identified 36 genes that may play a role in predisposition to physical activity motivation.”
Now that the researchers have identified these specific genes, they plan on continuing their research to explore the effects each gene has on motivation to exercise.

Couch Potatoes May Be Genetically Predisposed to Being Lazy

Studies show 97 percent of American adults get less than 30 minutes of exercise a day, which is the minimum recommended amount based on federal guidelines. New research from the University of Missouri suggests certain genetic traits may predispose people to being more or less motivated to exercise and remain active. Frank Booth, a professor in the MU College of Veterinary Medicine, along with his post-doctoral fellow Michael Roberts, were able to selectively breed rats that exhibited traits of either extreme activity or extreme laziness. They say these rats indicate that genetics could play a role in exercise motivation, even in humans.

“We have shown that it is possible to be genetically predisposed to being lazy,” Booth said. “This could be an important step in identifying additional causes for obesity in humans, especially considering dramatic increases in childhood obesity in the United States. It would be very useful to know if a person is genetically predisposed to having a lack of motivation to exercise, because that could potentially make them more likely to grow obese.”

In their study published in the American Journal of Physiology: Regulatory, Integrative and Comparative Physiology on April 3, 2013, Roberts and Booth put rats in cages with running wheels and measured how much each rat willingly ran on their wheels during a six-day period. They then bred the top 26 runners with each other and bred the 26 rats that ran the least with each other. They repeated this process through 10 generations and found that the line of running rats chose to run 10 times more than the line of “lazy” rats.

Once the researchers created their “super runner” and “couch potato” rats, they studied the levels of mitochondria in muscle cells, compared body composition and conducted thorough genetic evaluations through RNA deep sequencing of each rat.

“While we found minor differences in the body composition and levels of mitochondria in muscle cells of the rats, the most important thing we identified were the genetic differences between the two lines of rats,” Roberts said. “Out of more than 17,000 different genes in one part of the brain, we identified 36 genes that may play a role in predisposition to physical activity motivation.”

Now that the researchers have identified these specific genes, they plan on continuing their research to explore the effects each gene has on motivation to exercise.

Filed under physical exercise obesity genes genetics mitochondria neuroscience science

39 notes

Shedding light on a gene mutation that causes signs of premature aging

Research from Western University and Lawson Health Research Institute sheds new light on a gene called ATRX and its function in the brain and pituitary. Children born with ATRX syndrome have cognitive defects and developmental abnormalities. ATRX mutations have also been linked to brain tumors.

image

Dr. Nathalie Bérubé, PhD, and her colleagues found mice developed without the ATRX gene had problems in in the forebrain, the part of the brain associated with learning and memory, and in the anterior pituitary which has a direct effect on body growth and metabolism. The mice, unexpectedly, also displayed shortened lifespan, cataracts, heart enlargement, reduced bone density, hypoglycemia; in short, many of the symptoms associated with aging. The research is published in the Journal of Clinical Investigation.

Ashley Watson, a PhD candidate working in the Bérubé lab and the first author on the paper, discovered the loss of ATRX caused DNA damage especially at the ends of chromosomes which are called telomeres. She investigated further and discovered the damage is due to problems during DNA replication, which is required before the onset of cell division. Basically, the ATRX protein was needed to help replicate the telomere.

Working with Frank Beier of the Department of Physiology and Pharmacology at Western’s Schulich School of Medicine & Dentistry, the researchers made another discovery. “Mice that developed without ATRX were small at birth and failed to thrive, and when we looked at the skeleton of these mice, we found very low bone mineralization. This is another feature found in mouse models of premature aging,” says Bérubé, an associate professor in the Departments of Biochemistry and Paediatrics at Schulich Medicine & Dentistry, and a scientist in the Molecular Genetics Program at the Children’s Health Research Institute within Lawson. “We found the loss of ATRX increases DNA damage locally in the forebrain and anterior pituitary, resulting in systemic defects similar to those seen in aging.”

The researchers say the lack of ATRX in the anterior pituitary caused problems with the thyroid, resulting in low levels of a hormone called insulin-like growth factor-one (IGF-1) in the blood. There are theories that low IGF-1 can deplete stores of stem cells in the body, and Bérubé says that’s one of the explanations for the premature aging.

(Source: communications.uwo.ca)

Filed under brain ATRX syndrome ATRX gene forebrain genetics aging neuroscience science

64 notes

Neuroscientists show ’jumping genes’ may contribute to aging-related brain defects
As the body ages, the physical effects are notable; wrinkles in the skin appear, physical exertion becomes harder. But there are also less visible processes going on. Inside aging brains there is another phenomenon at work, which may contribute to age-related brain defects.
In a paper published in the journal Nature Neuroscience CSHL Associate Professor Joshua Dubnau and colleagues show that so-called “jumping genes,” or transposons, increase in abundance and activity in the brains of fruit flies as they age.
Originally discovered at CSHL by Professor Barbara McClintock while working on maize (corn) in the 1940s, transposons are typically repeat DNA sequences that insert themselves into the DNA of an animal or plant.
The moniker “jumping genes” comes from the fact that when activated they can reinsert themselves, or transpose, into another part of the genome. In the course of doing so they are thought to either provide variations in genetic function or, especially in the germline, induce potentially fatal disruptive defects.
Jumping genes in the brains of fruit flies
The median lifespan of a fruit fly can be measured in days. The average fly lives for somewhere between 40-50 days. But they provide a powerful model with which to get at the genetics of things like aging and brain function, including memory.
Dubnau’s interest was piqued by an experiment in which his team showed that when the activity of a protein called Ago2 (Argonaute 2) was perturbed, so was long-term memory—which was tested using a trained Pavolvian response to smell. “This is a neurodegenerative defect that gets profoundly more apparent with age of the flies,” notes Dubnau.
Since Ago2 is known to be involved in protecting against transposon activity in fruit flies, Dubnau and colleagues in his lab, including Wanhe Li and Lisa Prazak, were compelled to look for transposons.
Though transposons have been shown to be active during normal brain development, they are silenced soon afterward. The implication is that they have some functional role in development.
When Dubnau’s group looked for transposons they found that there is a marked increase in transposon levels in the brain cells, or neurons, by 21 days of age in normal fruit flies. The levels were observed to increase steadily with age. These transposons, including one in particular called gypsy, were highly active, jumping from place to place in the genome.
When they blocked Ago2 from being expressed in fruit flies, transposons accumulated at a much younger age. In fact the levels of transposons in young Ago2 “knock-out” flies were equivalent to those in much older normal flies, and increased further still as the Ago2 knock-out flies aged.
Accompanying this transposon accumulation were defects in long-term memory that mirrored those usually seen in much older flies, as well as a much-reduced lifespan. “Essentially the Ago2 knock out flies have no long-term memory by the time they are 20 days old, while normal flies have a normal long-term memory at the same age,” Dubnau reports.
In a previous paper the Dubnau lab, in collaboration with CSHL Assistant Professor Molly Hammell, established a connection between transposons and devastating neurodegenerative diseases such ALS (amyotrophic lateral sclerosis, or Lou Gehrig’s disease) and FTLD (frontotemporal lobar degeneration). The link was the protein TDP-43, which they showed controls transposon activity.
Taken together with the results in his team’s new paper, Dubnau proposes that a “transposon storm” may be responsible for age-related neurodegeneration as well as the pathology seen in some neurodegenerative disorders.
However, his studies so far don’t address whether transposons are the cause or an effect of aging-related brain defects. “The next step will be to activate transposons by genetically manipulating fruit flies and ask whether they are a direct cause of neurodegeneration,” Dubnau says.

Neuroscientists show ’jumping genes’ may contribute to aging-related brain defects

As the body ages, the physical effects are notable; wrinkles in the skin appear, physical exertion becomes harder. But there are also less visible processes going on. Inside aging brains there is another phenomenon at work, which may contribute to age-related brain defects.

In a paper published in the journal Nature Neuroscience CSHL Associate Professor Joshua Dubnau and colleagues show that so-called “jumping genes,” or transposons, increase in abundance and activity in the brains of fruit flies as they age.

Originally discovered at CSHL by Professor Barbara McClintock while working on maize (corn) in the 1940s, transposons are typically repeat DNA sequences that insert themselves into the DNA of an animal or plant.

The moniker “jumping genes” comes from the fact that when activated they can reinsert themselves, or transpose, into another part of the genome. In the course of doing so they are thought to either provide variations in genetic function or, especially in the germline, induce potentially fatal disruptive defects.

Jumping genes in the brains of fruit flies

The median lifespan of a fruit fly can be measured in days. The average fly lives for somewhere between 40-50 days. But they provide a powerful model with which to get at the genetics of things like aging and brain function, including memory.

Dubnau’s interest was piqued by an experiment in which his team showed that when the activity of a protein called Ago2 (Argonaute 2) was perturbed, so was long-term memory—which was tested using a trained Pavolvian response to smell. “This is a neurodegenerative defect that gets profoundly more apparent with age of the flies,” notes Dubnau.

Since Ago2 is known to be involved in protecting against transposon activity in fruit flies, Dubnau and colleagues in his lab, including Wanhe Li and Lisa Prazak, were compelled to look for transposons.

Though transposons have been shown to be active during normal brain development, they are silenced soon afterward. The implication is that they have some functional role in development.

When Dubnau’s group looked for transposons they found that there is a marked increase in transposon levels in the brain cells, or neurons, by 21 days of age in normal fruit flies. The levels were observed to increase steadily with age. These transposons, including one in particular called gypsy, were highly active, jumping from place to place in the genome.

When they blocked Ago2 from being expressed in fruit flies, transposons accumulated at a much younger age. In fact the levels of transposons in young Ago2 “knock-out” flies were equivalent to those in much older normal flies, and increased further still as the Ago2 knock-out flies aged.

Accompanying this transposon accumulation were defects in long-term memory that mirrored those usually seen in much older flies, as well as a much-reduced lifespan. “Essentially the Ago2 knock out flies have no long-term memory by the time they are 20 days old, while normal flies have a normal long-term memory at the same age,” Dubnau reports.

In a previous paper the Dubnau lab, in collaboration with CSHL Assistant Professor Molly Hammell, established a connection between transposons and devastating neurodegenerative diseases such ALS (amyotrophic lateral sclerosis, or Lou Gehrig’s disease) and FTLD (frontotemporal lobar degeneration). The link was the protein TDP-43, which they showed controls transposon activity.

Taken together with the results in his team’s new paper, Dubnau proposes that a “transposon storm” may be responsible for age-related neurodegeneration as well as the pathology seen in some neurodegenerative disorders.

However, his studies so far don’t address whether transposons are the cause or an effect of aging-related brain defects. “The next step will be to activate transposons by genetically manipulating fruit flies and ask whether they are a direct cause of neurodegeneration,” Dubnau says.

Filed under brain aging jumping genes transposons fruit flies genetics neuroscience science

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