Posts tagged science

Rapamycin, a drug used to prevent rejection in transplants, could delay the onset of neurodegenerative diseases such as Alzheimer’s and Parkinson’s. This is the main conclusion of a study published in the Nature in which has collaborated the researcher Isidro Ferrer, head of the group of Neuropathology at the Bellvitge Biomedical Research Institute (IDIBELL) and the Bellvitge University Hospital and Full Professor of Pathological Anatomy at the University of Barcelona. The research was led by researchers from the International School for Advanced Studies (SISSA) in Trieste (Italy).

The collaboration of the research group led by Dr. Ferrer with SISSA researchers began five years ago when they observed that Parkinson’s patients showed a deficit in UCHL1 protein. At that time, researchers didn’t know what mechanism produced this deficit. To discover it a European project was launched. It was coordinated by the Italian researchers and participated by other European research groups, including the group led by Dr. Ferrer. The project, called Dopaminet, focused on how dopaminergic neurons (brain cells whose neurotransmitter is dopamine) are involved in Parkinson’s disease.

Contrary to most common hypothesis that a DNA fragment encodes a protein through a messenger RNA molecule, the researchers found that it also works in reverse. They found a balance between the protein and its mirror protein, which is configured in reverse, and they are mutually controlled. If the protein mirror is located in the nucleus of the cell, it does not interact with the protein, while if it is in the cytoplasm, then both of them interact.

In the case of Parkinson’s disease the protein UCHL1 appears reduced and also its mirror protein is localized in the nucleus, and in the cytoplasm. Thus, the researchers sought a method to extract the mirror protein from the nucleus and made it interact with the original UCHL1 protein. The authors found that rapamycin was able to extract them from the nucleus. The drug allows the two proteins, the UCHL1 and its mirror, hold together in the cytoplasm, which would correct the mistakes that occur in Parkinson’s disease.

This in vitro research has allowed describing a new unknown mechanism. It is necessary that the UCHL1 mirror protein should accumulate in the nucleus and escape from the cytoplasm and join the UCLH1 protein. The combination of both makes the system work.

"The rapamycin can not cure Parkinson’s disease, but it may delay the onset of neurodegenerative diseases such as Alzheimer’s and Parkinson’s itself. Rapamycin can protect and delay the beginning of these diseases. It can complete the treatment, but it should be combined with other existing treatments", explains Isidro Ferrer.

Anyway, it is still far its application in patients. The next step is to validate these results in animal models and study the effects of rapamycin in combination with other drugs.

(Source: idibell.cat)

Scientists are presenting new research on how the brain develops during the dynamic and vulnerable transition period from childhood to adulthood. The findings underscore the uniqueness of adolescence, revealing factors that may influence depression, decision-making, learning, and social relationships.

The findings were presented at Neuroscience 2012, the annual meeting of the Society for Neuroscience and the world’s largest source of emerging news about brain science and health.

The brain’s “reward system,” those brain circuits and structures that mediate the experience and pursuit of pleasure, figured prominently in several studies. The studies shed light on adolescents’ ability to control impulsivity and think through problems; reveal physical changes in the “social brain;” document connections between early home life and brain function in adolescence; and examine the impact of diet on depressive-like behavior in rodents.

Today’s new findings show that:

• Adolescents can throw impulsivity out the window when big rewards are at stake. The bigger the reward, the more thoughtful they can be, calling on important brain regions to gather and weigh evidence, and make decisions that maximize gains (BJ Casey, PhD).
• Rodents that receive an omega-3 fatty acid in their diets, from gestation through their early development, appear less vulnerable to depressive-like behaviors during adolescence (Christopher Butt, PhD).
• Depression in older adolescent boys may be associated with changes in communication between regions of the brain that process reward. At the same time, the study found possible connections between early emotional attachments — particularly with mothers — and later reward system function (Erika Forbes, PhD).
• Early cognitive stimulation appears to predict the thickness of parts of the human cortex in adolescence, and experiences at age four appear to have a greater impact than those at age eight (Martha Farah, PhD).
• During the span of adolescence, the volume of the “social brain” — those areas that deal with understanding other people — changes substantially, with notable gender differences (Kathryn Mills, BA).

"Advances in neuroscience continue to delve deeper and deeper into the unique and dynamically changing biology of the adolescent brain," said press conference moderator Jay Giedd, MD, of the National Institute of Mental Health, an expert on childhood and adolescent brain development. "The insights are beginning to elucidate the mechanisms that make the teen years a time of particular vulnerabilities but also a time of great opportunity."

(Source: sciencedaily.com)

Neuroscientists from New York University and the University of California, Irvine have isolated the “when” and “where” of molecular activity that occurs in the formation of short-, intermediate-, and long-term memories. Their findings, which appear in the journal the Proceedings of the National Academy of Sciences, offer new insights into the molecular architecture of memory formation and, with it, a better roadmap for developing therapeutic interventions for related afflictions.

“Our findings provide a deeper understanding of how memories are created,” explained the research team leader Thomas Carew, a professor in NYU’s Center for Neural Science and dean of NYU’s Faculty of Arts and Science. “Memory formation is not simply a matter of turning molecules on and off; rather, it results from a complex temporal and spatial relationship of molecular interaction and movement.”

Neuroscientists have previously uncovered different aspects of molecular signaling relevant to the formation of memories. But less understood is the spatial relationship between molecules and when they are active during this process.

To address this question, the researchers studied the neurons in Aplysia californica, the California sea slug. Aplysia is a model organism that is quite powerful for this type of research because its neurons are 10 to 50 times larger than those of higher organisms, such as vertebrates, and it possesses a relatively small network of neurons—characteristics that readily allow for the examination of molecular signaling during memory formation. Moreover, its coding mechanism for memories is highly conserved in evolution, and thus is similar to that of mammals, making it an appropriate model for understanding how this process works in humans.

The scientists focused their study on two molecules, MAPK and PKA, which earlier research has shown to be involved in many forms of memory and synaptic plasticity—that is, changes in the brain that occur after neuronal interaction. But less understood was how and where these molecules interacted.

To explore this, the researchers subjected the sea slugs to sensitization training, which induces increased behavioral reflex responsiveness following mild tail shock, or in this study, mild activation of the nerve form the tail. They then examined the subsequent molecular activity of both MAPK and PKA. Both molecules have been shown to be involved in the formation of memory for sensitization, but the nature of their interaction is less clear.

What they found was MAPK and PKA coordinate their activity both spatially and temporally in the formation of memories. Specifically, in the formation of intermediate-term (i.e., hours) and long-term (i.e., days) memories, both MAPK and PKA activity occur, with MAPK spurring PKA action. By contrast, for short-term memories (i.e., less than 30 minutes), only PKA is active, with no involvement of MAPK.

(Source: nyu.edu)

A study by researchers from Emory University and Indiana University found that the beneficial effects daily exercise can have on the regeneration of nerves also require androgens such as testosterone in both males and females. It is the first report of both androgen-dependence of exercise on nerve regeneration and of an androgenic effect of exercise in females.

"The findings will provide a basis for the development of future treatment strategies for patients suffering peripheral nerve injuries," said Dale Sengelaub, professor in the Department of Psychological and Brain Sciences at IU. "And they underscore the need to tailor those treatments differently for men and women."

The researchers discussed the study on Monday at the Neuroscience 2012 scientific meeting in New Orleans.

Injuries to peripheral nerves are common. Hundreds of thousands of Americans are victims of traumatic injuries each year, and non-traumatic injuries, such as carpal tunnel syndrome, are found in even higher numbers. The researchers previously showed that two weeks of moderate daily exercise substantially improves regeneration of cut nerves and leads to functional recovery in mice, though different types of exercise are required to produce the effect in males and females. They now report that these beneficial effects of exercise require androgens such as testosterone in both males and females.

In the study they conducted, they exercised three groups of male and female mice. Nerves of the three groups were cut and surgically repaired. Once group received the drug flutamide, which blocks the androgen receptor. A second group received a placebo treatment. The third group was unexercised. Regenerating nerve fibers in the placebo group grew to more than twice the length of those in unexercised mice in both males and females. In flutamide-treated mice, the effects of exercise were blocked completely in both sexes.

The Society of Neuroscience is promoting the study (“Enhancement of peripheral axon regeneration by exercise requires androgen receptor signaling in both male and female mice”) to media covering the conference as a “Hot Topic.”

(Source: eurekalert.org)