Snapshots of Life: Growing Mini-Brains in a Dish

Brain grown in a lab dish

Credit: Collin Edington and Iris Lee, Department of Biomedical Engineering, MIT

Something pretty incredible happens—both visually and scientifically—when researchers spread neural stem cells onto a gel-like matrix in a lab dish and wait to see what happens. Gradually, the cells differentiate and self-assemble to form cohesive organoids that resemble miniature brains!

In this image of a mini-brain organoid, the center consists of a clump of neuronal bodies (magenta), surrounded by an intricate network of branching extensions (green) through which these cells relay information. Scattered throughout the mini-brain are star-shaped astrocytes (red) that serve as support cells.

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Adding Letters to the DNA Alphabet

semi-synthetic bacterium

Credit: William B. Kiosses

The recipes for life, going back billions of years to the earliest single-celled organisms, are encoded in a DNA alphabet of just four letters. But is four as high as the DNA code can go? Or, as researchers have long wondered, is it chemically and biologically possible to expand the DNA code by a couple of letters?

A team of NIH-funded researchers is now answering these provocative questions. The researchers recently engineered a semi-synthetic bacterium containing DNA with six letters, including two extra nucleotides [1, 2]. Now, in a report published in Nature, they’ve taken the next critical step [3]. They show that bacteria, like those in the photo, are not only capable of reliably passing on to the next generation a DNA code of six letters, they can use that expanded genetic information to produce novel proteins unlike any found in nature.

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Creative Minds: Taking Aim at Adverse Drug Reactions

Sherrie Divito

Sherrie Divito

As a practicing dermatologist, Sherrie Divito sees lots of patients each week at Brigham and Women’s Hospital, Boston. She also sees lots of research opportunities. One that grabbed her attention is graft-versus-host disease (GvHD), which can arise after a bone-marrow transplant for leukemia, lymphoma, or various other diseases. What happens is immune cells in the donated marrow recognize a transplant patient’s body as “foreign” and launch an attack. Skin is often attacked first, producing a severe rash that is a harbinger of complications to come in other parts of the body.

But Divito saw something else: it’s virtually impossible to distinguish between an acute GvHD-caused rash and a severe skin reaction to drugs, from amoxicillin to carbamazepine. In her GvHD studies, Divito had been researching a recently identified class of immune cell called tissue-resident memory T (Trm) cells. They remain in skin rather than circulating in the bloodstream. The clinical similarities made Divito wonder whether Trm cells may also help to drive severe skin allergies to drugs.

Divito has received a 2016 NIH Director’s Early Independence Award to find out. If correct, Divito will help not only to improve the lives of thousands of people with GvHD, but potentially benefit the millions of other folks who experience adverse reactions to drug.

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Creative Minds: Seeing Memories in a New Light

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.

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Clinical Trials Bring Hope to Kids with Spinal Muscular Atrophy

Faith Fortenberry

More than a decade ago, the NIH’s National Institute of Neurological Disorders and Stroke (NINDS) launched a special project to accelerate the translation of basic scientific discoveries into new treatments for a rare and often fatal disease. Five-year-old Faith Fortenberry whom you see above is among the kids who may benefit from the success of this pioneering endeavor.

Faith was born with spinal muscular atrophy (SMA), a hereditary neurodegenerative disease that can affect movement, breathing, and swallowing. When the NIH project began, there was no treatment for SMA, but researchers had discovered that mutations in the SMN1 gene were responsible for the disorder. Such mutations cause a deficiency of SMN protein, leading to degeneration of neurons in the brain and spinal cord, and progressive muscle weakness throughout the body. The NIH effort supported research to discover ways of raising SMN levels in cells grown in lab dishes, and then worked closely with patient advocates and pharmaceutical companies to move the most promising leads into drug development and clinical testing.

Given the desperate need for SMA treatments and all of the scientific energy that’s been devoted to pursuing them, I’ve been following this field closely. So, I was very encouraged to learn recently about the promising results of human tests of not just one—but two—new treatments for SMA [1, 2]. Continue reading