Biomedical Beat - A monthly digest of research news from NIGMS

IN THIS ISSUE . . .
July 21, 2010

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The National Institute of General Medical Sciences (NIGMS), one of the National Institutes of Health, supports all research featured in this digest. Although only the lead scientists are named, coworkers and other collaborators also contributed to the findings. To read additional news items, visit NIGMS News, Twitter or Facebook. To check out free NIGMS publications, go to the order form.

Cool Video: Cloud-Like Active Site

Courtesy of bioinorganic chemist John H. Enemark at the University of Arizona.

It may look like a gyrating, Skittle-eating cloud, but it actually represents the active site of sulfite oxidase, an enzyme essential for normal neurological development in children. Look deep inside the channel opening to see a ball-and-stick model of a complex containing the element molybdenum (light blue ball) that helps pass an oxygen atom (red ball at far end of channel) to trigger a catalytic reaction. The channel itself is lined with a chloride ion (green) and water molecules (red). Knowing more about the enzyme's active site will help scientists better understand sulfite oxidase deficiency, a fatal neurological disease. Courtesy of bioinorganic chemist John H. Enemark at the University of Arizona.

Enemark lab

Stopping Scarring in its Tracks

An illustration of a skin cross-section. Courtesy of NIGMS.
An illustration of a skin cross-section. Courtesy of NIGMS.
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While the healing process repairs injured tissues, it can go too far. Fibroblast cells normally aid healing, but too much of their activity can cause scarring. A team led by Lester Lau, a cell biologist at the University of Illinois at Chicago, discovered that a protein called CCN1 helps prevent fibroblasts from causing excessive scar tissue. They pinpointed the mechanisms underlying CCN1's effects on fibroblasts and showed that applying CCN1 at the site of a skin wound limits scar tissue formation. Because the wound healing process has many similarities across cells, organs and species, the results may shed light on how tissue repair occurs throughout the human body.

Full story
Lau profile
Article abstract (from the July issue of Nature Cell Biology)

LEOPARD Skin Cells

Heart cells derived from LEOPARD syndrome iPS cells. Heart muscle fibers are stained red. Courtesy of Carvajal-Vergara et al, Nature.
Heart cells derived from LEOPARD syndrome iPS cells. Heart muscle fibers are stained red. Courtesy of Carvajal-Vergara et al, Nature.
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LEOPARD syndrome is a rare genetic disease that causes unsafe super-thick heart muscle in addition to facial, skin and sensory abnormalities. To better understand the disease, Ihor Lemischka, a stem cell biologist at Mount Sinai Medical Center, developed a new model using skin cells from people with LEOPARD syndrome. He and his team reprogrammed these cells into induced pluripotent stem (iPS) cells, which then became heart muscle cells showing telltale signs of the disease. Because the cells contain the exact genetic profile of individuals' diseased cells, this method could help scientists determine the cellular paths that lead to disease and help identify drug targets for the disorder.

Full story
Lemischka lab
Article abstract (from the June 10 issue of Nature)

Tool for Tracking Carbs

Cell division in zebrafish embryos. Courtesy of the Bertozzi lab.
Cell division in zebrafish embryos. Courtesy of the Bertozzi lab.
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Carbohydrates called glycans dot the surface of every cell in our bodies, and they play an important role in development. Now chemical biologist Carolyn Bertozzi and her team at the University of California, Berkeley, have created a tool for imaging the carbs' activity during the earliest stages of embryo development in zebrafish, a model organism. The scientists used a two-step method to label and simultaneously track two classes of glycans as they rapidly moved along the groove of dividing cells. In the future, scientists could use the technique to track other molecules and gain insights into key developmental events.

Full story
Bertozzi lab
Article abstract (from the June 8 issue of PNAS)



Piecing Together a Better Process for Drug Development

Model of trifluoromethyl attached to a ring of six carbons.
Model of trifluoromethyl attached to a ring of six carbons.
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A chemical group called trifluoromethyl dramatically influences the properties of drugs and other important compounds, and pharmaceutical manufacturers often affix this group to certain drugs so they remain active longer. Despite its importance, scientists have struggled to figure out how to attach the chemical group in a convenient manner. A group led by MIT chemist Stephen Buchwald has found a way. With the right catalyst (a molecule that hastens the reaction), the scientists developed a process for adding the trifluoromethyl group that may ultimately help to streamline and lower the cost of drug synthesis and discovery.

Full story
Buchwald lab
Article abstract (from the June 25 issue of Science)