Scientists Identify New Stem Cells with Therapeutic Potential

The discovery, published in the journal PLOS Biology, offers new opportunities in the treatment of cardiovascular diseases, cancer and many other diseases.

The growth of new blood vessels – angiogenesis – occurs during the repair of damaged tissue and organs in adults. However, malignant tumors also grow new blood vessels in order to receive oxygen and nutrients. As such, angiogenesis is both beneficial and detrimental to health, depending on the context, requiring therapeutic approaches that can either help to stimulate or prevent it. Therapeutics that aim to prevent the growth of new blood vessels are already in use, but the results are often more modest than predicted.

For more than a decade, Prof Petri Salvén of the University of Helsinki and his colleagues have studied the mechanisms of angiogenesis to discover how blood vessel growth could be prevented or accelerated effectively.

“We succeeded in isolating endothelial cells with a high rate of division in the blood vessel walls of mice. We found these same cells in human blood vessels and blood vessels growing in malignant tumors in humans. These cells are known as vascular endothelial stem cells. In a cell culture, one such cell is capable of producing tens of millions of new blood vessel wall cells,” Prof Salvén said.

From their studies in mice, the team was able to show that the growth of new blood vessels weakens, and the growth of malignant tumors slows, if the amount of these cells is below normal. Conversely, new blood vessels form where these stem cells are implanted.

Solving Stem Cell Mysteries

The ability of embryonic stem cells to differentiate into different types of cells with different functions is regulated and maintained by a complex series of chemical interactions, which are not well understood. Learning more about this process could prove useful for stem cell-based therapies down the road. New research from a team led by Carnegie’s Yixian Zheng zeroes in on the process by which stem cells maintain their proper undifferentiated state. Their results are published in Cell October 26.

Embryonic stem cells go through a process called self-renewal, wherein they undergo multiple cycles of division while not differentiating into any other type of cells. This process is dependent on three protein networks, which guide both self-renewal and eventual differentiation. But the integration of these three networks has remained a mystery.

Using a combination of genetic, protein-oriented and physiological approaches involving mouse embryonic stem cells, the team—which also included current and former Carnegie scientists Junling Jia, Xiaobin Zheng, Junqi Zhang, Anying Zhang, and Hao Jiang—uncovered a mechanism that integrates all three networks involved in embryonic stem cell self-renewal and provide a critical missing link to understanding this process.

The key is a protein called Utf1. It serves three important roles. First, it balances between activating and deactivating the necessary genes to direct the cell toward differentiation. At the same time, it acts on messenger RNA that is the transcription product of the genes when they’re activated by tagging it for degradation, rather than allowing it to continue to serve its cellular function. Lastly, it blocks a genetic feedback loop that normally inhibits cellular proliferation, allowing it to occur in the rapid nature characteristic of embryonic stem cells.

People plus: is transhumanism the next stage in our evolution?

Inviting artificial intelligence into our bodies has appeal – but it also carries certain risks.

I have often wondered what it would be like to rid myself of a keyboard for data entry, and a computer screen for display. Some of my greatest moments of reflection are when I am in the car driving long distances, cooking in my kitchen, watching the kids play at the park, waiting for a doctor’s appointment or on a plane thousands of metres above sea level.

I have always been great at multitasking but at these times it is often not practical or convenient to be head down typing on a laptop, tablet or smartphone.

It would be much easier if I could just make a mental note to record an idea and have it recorded, there and then. And who wouldn’t want the ability to “jack into” all the world’s knowledge sources in an instant via a network?

Who wouldn’t want instant access to their life-pages filled with all those memorable occasions? Or even the ability to slow down the process of ageing, as long as living longer equated to living with mind and body fully intact, as outlined in the video.

Transhumanists would have us believe that these things are not only possible but inevitable. In short: we Homo sapiens may dictate the next stage of our evolution through our use of technology.

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sutured-infection:

Young man wearing a pair of artificial arms and two artificial legs, 1890-1910

Evolution is actually pretty predictable

“Is evolution predictable? To a surprising extent the answer is ‘yes’,” says Princeton professor Peter Andolfatto.

New research by Andolfatto and colleagues published in the journal Science suggests that knowledge of a species’ genes—and how certain external conditions affect the proteins encoded by those genes—could be used to determine a predictable evolutionary pattern driven by outside factors.

Scientists could then pinpoint how the diversity of adaptations seen in the natural world developed even in distantly related animals.

The researchers carried out a survey of DNA sequences from 29 distantly related insect species, the largest sample of organisms yet examined for a single evolutionary trait. Fourteen of these species have evolved a nearly identical characteristic due to one external influence—they feed on plants that produce cardenolides, a class of steroid-like cardiotoxins that are a natural defense for plants such as milkweed and dogbane.

Though separated by 300 million years of evolution, these diverse insects—which include beetles, butterflies, and aphids—experienced changes to a key protein called sodium-potassium adenosine triphosphatase, or the sodium-potassium pump, which regulates a cell’s crucial sodium-to-potassium ratio.

Did bacteria spark evolution of multicellular life?

Bacteria have a bad rap as agents of disease, but scientists are increasingly discovering their many benefits, such as maintaining a healthy gut.

A new study now suggests that bacteria may also have helped kick off one of the key events in evolution: the leap from one-celled organisms to many-celled organisms, a development that eventually led to all animals, including humans.

Published this month in the inaugural edition of the new online journal eLife, the study by University of California, Berkeley, and Harvard Medical School scientists involves choanoflagellates (aka “choanos”), the closest living relatives of animals. These microscopic, one-celled organisms sport a long tail or flagellum, tentacles for grabbing food and are members of the ocean’s plankton community. As our closest living relative, choanos offer critical insights into the biology of their last common ancestor with animals, a unicellular or colonial organism that lived and died over 650 million years ago.

“Choanoflagellates evolved not long before the origin of animals and may help reveal how animals first evolved,” said senior author Nicole King, UC Berkeley associate professor of molecular and cell biology.

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Higher-math skills entwined with lower-order magnitude sense

The ability to learn complex, symbolic math is a uniquely human trait, but it is intricately connected to a primitive sense of magnitude that is shared by many animals, finds a study to be published by the Proceedings of the National Academy of Sciences (PNAS).

"Our results clearly show that uniquely human branches of mathematics interface with an evolutionarily primitive general magnitude system," says lead author Stella Lourenco, a psychologist at Emory University. "We were able to show how variations in both advanced arithmetic and geometry skills specifically correlated with variations in our intuitive sense of magnitude."

Babies as young as six months can roughly distinguish between less and more, whether it’s for a number of objects, the size of objects, or the length of time they see the objects. This intuitive, non-verbal sense of magnitude, which may be innate, has also been demonstrated in non-human animals. When given a choice between a group of five bananas or two bananas, for example, monkeys will tend to take the bigger bunch.

"It’s obviously of adaptive value for all animals to be able to discriminate between less and more," Lourenco says. "The ability is widespread across the animal kingdom – fish, rodents and even insects show sensitivity to magnitude, such as the number of items in a set of objects."

Primates’ brains make visual maps using triangular grids

Primates’ brains see the world through triangular grids, according to a new study published online Sunday in the journal Nature.

Scientists at Yerkes National Primate Research Center, Emory University, have identified grid cells, neurons that fire in repeating triangular patterns as the eyes explore visual scenes, in the brains of rhesus monkeys.

The finding has implications for understanding how humans form and remember mental maps of the world, as well as how neurodegenerative diseases such as Alzheimer’s erode those abilities. This is the first time grid cells have been detected directly in primates. Grid cells were identified in rats in 2005, and their existence in humans has been indirectly inferred through magnetic resonance imaging.

Grid cells’ electrical activities were recorded by introducing electrodes into monkeys’ entorhinal cortex, a region of the brain in the medial temporal lobe. At the same time, the monkeys viewed a variety of images on a computer screen and explored those images with their eyes. Infrared eye-tracking allowed the scientists to follow which part of the image the monkey’s eyes were focusing on. A single grid cell fires when the eyes focus on multiple discrete locations forming a grid pattern.

"The entorhinal cortex is one of the first brain regions to degenerate in Alzheimer’s disease, so our results may help to explain why disorientation is one of the first behavioral signs of Alzheimer’s," says senior author Elizabeth Buffalo, PhD, associate professor of neurology at Emory University School of Medicine and Yerkes National Primate Research Center. "We think these neurons help provide a context or structure for visual experiences to be stored in memory."

"Our discovery of grid cells in primates is a big step toward understanding how our brains form memories of visual information," says first author Nathan Killian, a graduate student in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University. "This is an exciting way of thinking about memory that may lead to novel treatments for neurodegenerative diseases."

(Image credit: Mark Snelson)