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Meet Elizabeth Grice

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Elizabeth Grice
Elizabeth Grice
First job: Detasseling corn
Favorite food: Chocolate
Pets: An adopted shelter cat, Dolce
Favorite city: Athens, Greece
Hidden talent: Baking creative desserts
Credit: Bill Branson, NIH

Imagine a landscape with peaks and valleys, folds and niches, cool, dry zones and hot, wet ones. Every inch is swarming with diverse communities, but there are no cities, no buildings, no fields and no forests.

You’ve probably thought little about the inhabitants, but you see their environment every day. It’s your largest organ—your skin.

Elizabeth Grice, an assistant professor at the University of Pennsylvania, studies the skin microbiome to learn how and why bacteria colonize particular places on the body. Already, she’s found that the bacterial communities on healthy skin are different from those on diseased skin.

She hopes her work will point to ways of treating certain skin diseases, especially chronic wounds. “I like to think that I am making discoveries that will impact the way medicine is practiced,” she says.

Grice’s Findings

To investigate what role bacteria play in diabetic wounds, Grice and her colleagues took skin swabs from both diabetic and healthy mice, and then compared the two. They found that diabetic mice had about 40 times more bacteria on their skin, but it was concentrated into few species. A more diverse array of bacteria colonized the skin of healthy mice.

The researchers then gave each mouse a small wound and spent 28 days swabbing the sites to collect bacteria and observing how the skin healed. They found that wounds on diabetic mice started to increase in size at the same time as wounds on healthy mice began to heal. In about 2 weeks, most healthy mice looked as good as new. But most of the wounds on diabetic mice had barely healed even after a month.

Interestingly, bacterial communities in the wounds became more diverse in both groups of mice as they healed—although the wounds on diabetic mice still had less diversity than the ones on healthy mice.

“Bacterial diversity is probably a good thing, especially in wounds,” says Grice. “Often, potentially infectious bacteria are found on normal skin and are kept in check by the diversity of bacteria surrounding them.”

Grice and her colleagues also found distinctly different patterns of gene activity between the two groups of mice. As a result, the diabetic mice put out a longer-lasting immune response, including inflamed skin. Scientists believe prolonged inflammation might slow the healing process.

Grice’s team suspects that one of the main types of bacteria found on diabetic wounds, Staphylococcus, makes one of the inflammation-causing genes more active.

Now that they know more about the bacteria that thrive on diabetic wounds, Grice and her colleagues are a step closer to looking at whether they could reorganize these colonies to help the wounds heal.

Content adapted from the NIGMS Findings magazine article Body Bacteria.

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On the Trail of Drug-Defying Superbugs

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Antibiotic-resistant strains of Staphlyococcus aureus bacteria (purple) have become the most common cause of skin infections seen in hospital emergency departments. Credit: NIH’s National Institute of Allergy and Infectious Diseases.
Antibiotic-resistant strains of Staphlyococcus aureus bacteria (purple) have become the most common cause of skin infections seen in hospital emergency departments. Credit: NIH’s National Institute of Allergy and Infectious Diseases.

In the United States alone, at least 2 million people each year develop serious infections with bacteria that have become resistant to the antibiotics we use to combat them, and about 23,000 die, according to the Centers for Disease Control and Prevention. Antibiotic resistance can turn once-manageable infections into “superbug” diseases that are difficult—and sometimes impossible—to treat.

Scientists funded by the National Institutes of Health are studying many aspects of antibiotic resistance, including how it spreads. Read this Inside Life Science article for just a few research examples and how the work could aid efforts to curb the emergence of resistance.

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Revealing the Human Proteome

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An artistic interpretation of the human proteome. Credit: Corinne Sandone and Jennifer Fairman, Johns Hopkins University.
An artistic interpretation of the human proteome. Credit: Corinne Sandone and Jennifer Fairman, Johns Hopkins University.

Genes control the most basic functions of the cell, including what proteins to make and when. In 2003, the Human Genome Project created a draft map of our genes, and now researchers have completed a draft map of the human proteome—the set of all our proteins. The map, which includes proteins encoded by more than 17,000 genes as well as ones from regions of the genome previously thought to be non-coding, will help advance a broad range of research into human health and disease.

Read more about the proteome map in this NIH Research Matters article.

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Cool Image: Researching Regeneration in a Model Organism

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The isolated feeding tube of a flatworm.

The feeding tube, or pharynx, of a planarian worm with cilia shown in red and muscle fibers shown in green. Credit: Carrie Adler/Stowers Institute for Medical Research.

This rainbow-hued image shows the isolated feeding tube, or pharynx, of a tiny freshwater flatworm called a planarian, with the hairlike cilia in red and muscle fibers in green. Scientists use these wondrous worms, which have an almost infinite capacity to regrow all organs, as a simple model system for studying regeneration. A research team led by Alejandro Sánchez Alvarado of the Stowers Institute for Medical Research exploited a method known as selective chemical amputation to remove the pharynx easily and reliably. This allowed the team to conduct a large-scale genetic analysis of how stem cells in a planaria fragment realize what’s missing and then restore it. The researchers initially identified about 350 genes that were activated as a result of amputation. They then suppressed those genes one by one and observed the worms until they pinpointed one gene in particular—a master regulator called FoxA—whose absence completely blocked pharynx regeneration. Scientists believe that researching regeneration in flatworms first is a good way to gain knowledge that could one day be applied to promoting regeneration in mammals.

Learn more:
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Sánchez Lab

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Good Vibrations

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A knot-like structure in a section of RNA from a flavivirus
Findings in mice may lead to a drug-free, noninvasive way to treat chronic wounds in people with type 2 diabetes. Credit: Stock image.

For people living with type 2 diabetes, wounds often heal slowly, sometimes even becoming chronic. Now, scientists have shown that low-intensity vibrations can speed up the healing process in a strain of diabetic mice commonly used to study delayed wound healing. The research team, led by Timothy Kohof the University of Illinois at Chicago, found that exposing the mice to barely perceptible vibrations five times a week for just 30 minutes promoted wound healing by increasing the formation of new blood vessels and of granulation tissue, a type of tissue critical in the early stages of healing. If researchers can show that the vibration technique also works in humans, this approach could one day offer a drug-free, non-invasive therapy for chronic wounds in people with diabetes.

This work also was funded by NIH’s National Institute of Dental and Craniofacial Research.

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Learning How Mosquito-Borne Viruses Use Knot-like RNA to Cause Disease

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A knot-like structure in a section of RNA from a flavivirus
A knot-like structure in RNA enables flaviviruses to cause diseases like yellow fever, West Nile virus and dengue fever, which threaten roughly half the world’s population. Credit: Jeffrey Kieft.

Roughly half the world’s population is now at risk for mosquito-borne diseases other than malaria, such as yellow fever, West Nile virus and dengue fever. These three diseases are caused by flaviviruses, a type of virus that carries its genetic material as a single strand of RNA.

Flaviviruses have found a way not only to thwart our bodies’ normal defenses, but also to harness a human enzyme—paradoxically, one normally used to destroy RNA—to enhance their disease-causing abilities. A team of scientists led by Jeffrey Kieft at the University of Colorado at Denver found that flaviviruses accomplish both feats by bending and twisting a small part of their RNA into a knot-like structure.

The scientists set out to learn more about this unusual ability. First, they determined the detailed, three-dimensional architecture of the convoluted flaviviral RNA. Then, they examined several different variations of the RNA. In doing so, they pinpointed parts that are critical for forming the knot-like shape. If researchers can find a way to prevent the RNA from completing its potentially dangerous twist, they’ll be a step closer to developing a treatment for flaviviral diseases, which affect more than 100 million people worldwide.

This work also was supported by the National Institute of Allergy and Infectious Diseases and the National Cancer Institute.

Learn more:
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Knowing Networks

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Artist's rendition of a network diagram. Credit: Allison Kudla, Institute for Systems Biology.
Artist’s rendition of a network diagram. Credit: Allison Kudla, Institute for Systems Biology.

Networks—both real and virtual—are everywhere, from our social media circles to the power grid that delivers electricity. The interactions of genes, proteins and other molecules in a cell are examples of networks, too.

Scientists working in a field called systems biology study and chart living networks to learn how the individual parts work together to make a functioning whole and what happens when these complex, dynamic systems go awry. For example, the network diagram here depicts yeast cells (superimposed circles) and the biochemical “chatter” between them (lines) that tells the cells to gather together in clumps. This clumping helps them survive stressful conditions like a shortage of nutrients.

Network diagrams provide more than just hub-and-spoke pictures. They can yield information that helps us better understand—and potentially influence—complex phenomena that affect our health.

Read more about network analysis and systems biology in this Inside Life Science article.

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Multitarget Drugs to Challenge Microbial Resistance

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A group of purple, rod-shaped bacterial cells rendered by computer at Centers for Disease Control and Prevention by Melissa Brower.
Computer-generated image of drug-resistant Mycobacterium tuberculosis bacteria. Credit: Melissa Brower, Centers for Disease Control and Prevention.

Drugs that target a single essential protein in a microbial invader can be effective treatments. But the genomes of pathogens—including bacteria, fungi and parasites—mutate rapidly, and resistance can develop if a mutation changes a target protein’s structure. Molecules that interfere with multiple microbial proteins at once have the potential to overcome the growing problem of antimicrobial drug resistance.

Researchers led by Eric Oldfield of the University of Illinois recently explored whether an experimental drug called SQ109, developed to treat tuberculosis (TB), could be tweaked to attack multiple enzymes, as well as to kill different types of microbes. The scientists succeeded in creating several multitarget analogs of SQ109 that were more effective than the original drug at killing their target pathogens in laboratory experiments. These analogs included one compound that was five times more potent against the bacterium that causes TB while also being less toxic to a human cell line tested.

This work was also funded by the National Cancer Institute; the National Heart, Lung, and Blood Institute; the National Institute of Allergy and Infectious Diseases and the NIH Office of the Director.

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A Medicine’s Life Inside the Body

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Heart
Most often, the bloodstream is the vehicle for carrying medicines throughout the body. Credit: Stock image.

Pharmacology is the scientific field that studies how the body reacts to medicines and how medicines affect the body. Scientists funded by the National Institutes of Health are interested in many aspects of pharmacology, including one called pharmacokinetics, which deals with understanding the entire cycle of a medicine’s life inside the body.

Knowing more about each of the four main stages of pharmacokinetics—absorption, distribution, metabolism and excretion—aids the design of medicines that are more effective and that produce fewer side effects.

Read more about a medicine’s life inside the body in this Inside Life Science article.

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Understanding Complex Diseases Through Computation

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Scientists developed a computational method that could help identify various subtypes of complex diseases. Credit: Stock image

Complex diseases such as diabetes, cancer and asthma are caused by the intricate interplay of genetic, environmental and lifestyle factors that vary among affected individuals. As a result, the same medications may not work for every patient. Now, scientists have shown that a computational method capable of analyzing more than 100 clinical variables for a large group of people can identify various subtypes of asthma, which could ultimately lead to more targeted and personalized treatments. The research team, led by Wei Wu Exit icon of Carnegie Mellon University and Sally Wenzel of the University of Pittsburgh, used a computational approach developed by Wu to identify several patient clusters consistent with known subtypes of asthma, as well as a possible new subtype of severe asthma that does not respond well to conventional drug treatment. If supported by further studies, the researchers’ proposed approach could help improve the understanding, diagnosis and treatment not just of asthma but of other complex diseases.

This work also was funded by NIH’s National Heart, Lung, and Blood Institute.

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