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Helping People in Need of a Stem Cell Transplant

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Hoggatt and Chou in the lab

Caption: Study co-authors Jonathan Hoggatt (r) and Bin-Kuan Chou (l) look through a microscope at a patient’s mobilized stem cells.
Credit: Lee Hopkins, OLP Creative

In certain people with cancer or other serious diseases, transplants of healthy adult stem cells can be lifesaving. But donating blood-forming stem cells is a bit more complicated than giving blood. For example, stem-cell donors most often undergo five days of injections to build up enough of those vital cells in the blood for donation.

Wouldn’t it be great if we could find a way to make the donation process easier? Such improvements are now on the horizon.NIH-funded researchers recently found that, at least in mice, a single injection of two complementary treatments can generate enough stem cells in 15 minutes [1]. What’s more, stem cells harvested in this way have qualities that appear to increase the odds of transplant success.


Creative Minds: Seeing Memories in a New Light

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Steve Ramirez

Steve Ramirez/Joshua Sariñana

Whether it’s lacing up for a morning run, eating blueberry scones, or cheering on the New England Patriots, Steve Ramirez loves life and just about everything in it. As an undergraduate at Boston University, this joie de vivre actually made Ramirez anxious about choosing just one major. A serendipitous conversation helped him realize that all of the amazing man-made stuff in our world has a common source: the human brain.

So, Ramirez decided to pursue neuroscience and began exploring the nature of memory. Employing optogenetics (using light to control brain cells) in mice, he tagged specific neurons that housed fear-inducing memories, making the neurons light sensitive and amenable to being switched on at will.

In groundbreaking studies that earned him a spot in Forbes 2015 “30 Under 30” list, Ramirez showed that it’s possible to reactivate memories experimentally in a new context, recasting them in either a more negative or positive behavior-changing light [1–3]. Now, with support from a 2016 NIH Director’s Early Independence Award, Ramirez, who runs his own lab at Boston University, will explore whether activating good memories holds promise for alleviating chronic stress and psychiatric disease.


Finding Brain Circuits Tied to Alertness

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Everybody knows that it’s important to stay alert behind the wheel or while out walking on the bike path. But our ability to react appropriately to sudden dangers is influenced by whether we feel momentarily tired, distracted, or anxious. How is it that the brain can transition through such different states of consciousness while performing the same routine task, even as its basic structure and internal wiring remain unchanged?

A team of NIH-funded researchers may have found an important clue in zebrafish, a popular organism for studying how the brain works. Using a powerful new method that allowed them to find and track brain circuits tied to alertness, the researchers discovered that this mental state doesn’t work like an on/off switch. Rather, alertness involves several distinct brain circuits working together to bring the brain to attention. As shown in the video above that was taken at cellular resolution, different types of neurons (green) secrete different kinds of chemical messengers across the zebrafish brain to affect the transition to alertness. The messengers shown are: serotonin (red), acetylcholine (blue-green), and dopamine and norepinephrine (yellow).

What’s also fascinating is the researchers found that many of the same neuronal cell types and brain circuits are essential to alertness in zebrafish and mice, despite the two organisms being only distantly related. That suggests these circuits are conserved through evolution as an early fight-or-flight survival behavior essential to life, and they are therefore likely to be important for controlling alertness in people too. If correct, it would tell us where to look in the brain to learn about alertness not only while doing routine stuff but possibly for understanding dysfunctional brain states, ranging from depression to post-traumatic stress disorder (PTSD).


Aging Research: Plasma Protein Revitalizes the Brain

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Elixir of youth?For centuries, people have yearned for an elixir capable of restoring youth to their aging bodies and minds. It sounds like pure fantasy, but, in recent years, researchers have shown that the blood of young mice can exert a regenerative effect when transfused into older animals. Now, one of the NIH-funded teams that brought us those exciting findings has taken an early step toward extending them to humans.

In their latest work published in Nature, the researchers showed that blood plasma collected from the umbilical cords of newborn infants possesses some impressive rejuvenating effects [1]. When the human plasma was infused into the bloodstream of old mice, it produced marked improvements in learning and memory. Additional experiments traced many of those cognitive benefits to a specific protein called TIMP2—an unexpected discovery that could pave the way for the development of brain-boosting drugs to slow the effects of aging.


Mouse Study Finds Microbe Might Protect against Food Poisoning

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T mu in a mouse colon

Caption: Scanning electron microscopy image of T. mu in the mouse colon.
Credit: Aleksey Chudnovskiy and Miriam Merad, Icahn School of Medicine at Mount Sinai

Recently, we humans have started to pay a lot more attention to the legions of bacteria that live on and in our bodies because of research that’s shown us the many important roles they play in everything from how we efficiently metabolize food to how well we fend off disease. And, as it turns out, bacteria may not be the only interior bugs with the power to influence our biology positively—a new study suggests that an entirely different kingdom of primarily single-celled microbes, called protists, may be in on the act.

In a study published in the journal Cell, an NIH-funded research team reports that it has identified a new protozoan, called Tritrichomonas musculis (T. mu), living inside the gut of laboratory mice. That sounds bad—but actually this little wriggler was potentially providing a positive benefit to the mice. Not only did T. mu appear to boost the animals’ immune systems, it spared them from the severe intestinal infection that typically occurs after eating food contaminated with toxic Salmonella bacteria. While it’s not yet clear if protists exist that can produce similar beneficial effects in humans, there is evidence that a close relative of T. mu frequently resides in the intestines of people around the world.


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