Snapshots of Life: Healing Spinal Cord Injuries

Nerve cell on a nanofiber gel

Caption: Mark McClendon, Zaida Alvarez Pinto, Samuel I. Stupp, Northwestern University, Evanston, IL

When someone suffers a fully severed spinal cord, it’s considered highly unlikely the injury will heal on its own. That’s because the spinal cord’s neural tissue is notorious for its inability to bridge large gaps and reconnect in ways that restore vital functions. But the image above is a hopeful sight that one day that could change.

Here, a mouse neural stem cell  (blue and green) sits in a lab dish, atop a special gel containing a mat of synthetic nanofibers (purple). The cell is growing and sending out spindly appendages, called axons (green), in an attempt to re-establish connections with other nearby nerve cells.

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Snapshots of Life: Wired for Nerve Regeneration

Nerve cells

Credit: Laura Struzyna, Cullen Laboratory, Perelman School of Medicine, University of Pennsylvania, Philadelphia

Getting nerve cells to grow in the lab can be a challenge. But when it works, the result can be a thing of beauty for both science and art. What you see growing in the Petri dish shown above are nerve cells from an embryonic rat. On the bottom left is a dorsal root ganglion (dark purple), which is a cluster of sensory nerve bodies normally found just outside the spinal cord. To the right are the nuclei (light purple) and axons (green) of motor neurons, which are the nerve cells involved in forming key signaling networks.

Laura Struzyna, a graduate student in the lab of NIH grantee D. Kacy Cullen at the University of Pennsylvania’s Perelman School of Medicine, Philadelphia, is using laboratory-grown nerve cells in her efforts to learn how to bioengineer nerve grafts. The hope is this work will one day lead to grafts that can be used to treat people whose nerves have been damaged by car accidents or other traumatic injuries.

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Creative Minds: Modeling Neurobiological Disorders in Stem Cells

Feng Zhang

Feng Zhang

Most neurological and psychiatric disorders are profoundly complex, involving a variety of environmental and genetic factors. Researchers around the world have worked with patients and their families to identify hundreds of possible genetic leads to learn what goes wrong in autism spectrum disorder, schizophrenia, and other conditions. The great challenge now is to begin examining this growing cache of information more systematically to understand the mechanism by which these gene variants contribute to disease risk—potentially providing important information that will someday lead to methods for diagnosis and treatment.

Meeting this profoundly difficult challenge will require a special set of laboratory tools. That’s where Feng Zhang comes into the picture. Zhang, a bioengineer at the Broad Institute of MIT and Harvard, Cambridge, MA, has made significant contributions to a number of groundbreaking research technologies over the past decade, including optogenetics (using light to control brain cells), and CRISPR/Cas9, which researchers now routinely use to edit genomes in the lab [1,2].

Zhang has received a 2015 NIH Director’s Transformative Research Award to develop new tools to study multiple gene variants that might be involved in a neurological or psychiatric disorder. Zhang draws his inspiration from nature, and the microscopic molecules that various organisms have developed through the millennia to survive. CRISPR/Cas9, for instance, is a naturally occurring bacterial defense system that Zhang and others have adapted into a gene-editing tool.

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Creative Minds: Making a Miniature Colon in the Lab

Gut on a Chip

Caption: Top down view of gut tissue monolayer grown on an engineered scaffold, which guides the cells into organized crypts structures similar to the conformation of crypts in the human colon. Areas between the circles represent the flat lumenal surface.
Credit: Nancy Allbritton, University of North Carolina, Chapel Hill

When Nancy Allbritton was a child in Marksville, LA, she designed and built her own rabbit hutches. She also once took apart an old TV set to investigate the cathode ray tube inside before turning the wooden frame that housed the TV into a bookcase, which, by the way, she still has. Allbritton’s natural curiosity for how things work later inspired her to earn advanced degrees in medicine, medical engineering, and medical physics, while also honing her skills in cell biology and analytical chemistry.

Now, Allbritton applies her wide-ranging research background to design cutting-edge technologies in her lab at the University of North Carolina, Chapel Hill. In one of her boldest challenges yet, supported by a 2015 NIH Director’s Transformative Research Award, Allbritton and a multidisciplinary team of collaborators have set out to engineer a functional model of a large intestine, or colon, on a microfabricated chip about the size of a dime.

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Stem Cell Research: New Recipes for Regenerative Medicine

Cartilage and bone formation from stem cells

Caption: From stem cells to bone. Human bone cell progenitors, derived from stem cells, were injected under the skin of mice and formed mineralized structures containing cartilage (1-2) and bone (3).
Credit: Loh KM and Chen A et al., 2016

To help people suffering from a wide array of injuries and degenerative diseases, scientists and bioengineers have long dreamed of creating new joints and organs using human stem cells. A major hurdle on the path to achieving this dream has been finding ways to steer stem cells into differentiating into all of the various types of cells needed to build these replacement parts in a fast, efficient manner.

Now, an NIH-funded team of researchers has reported important progress on this front. The researchers have identified for the first time the precise biochemical signals needed to spur human embryonic stem cells to produce 12 key types of cells, and to do so rapidly. With these biochemical “recipes” in hand, researchers say they should be able to generate pure populations of replacement cells in a matter of days, rather than the weeks or even months it currently takes. In fact, they have already demonstrated that their high-efficiency approach can be used to produce potentially therapeutic amounts of human bone, cartilage, and heart tissue within a very short time frame.

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