Find and Replace: DNA Editing Tool Shows Gene Therapy Promise

Neutrophil being edited with CRISPR/Cas9

Caption: This image represents an infection-fighting cell called a neutrophil. In this artist’s rendering,  the cell’s DNA is being “edited” to help restore its ability to fight bacterial invaders.
Credit: NIAID, NIH

For gene therapy research, the perennial challenge has been devising a reliable way to insert safely a working copy of a gene into relevant cells that can take over for a faulty one. But with the recent discovery of powerful gene editing tools, the landscape of opportunity is starting to change. Instead of threading the needle through the cell membrane with a bulky gene, researchers are starting to design ways to apply these tools in the nucleus—to edit out the disease-causing error in a gene and allow it to work correctly.

While the research is just getting under way, progress is already being made for a rare inherited immunodeficiency called chronic granulomatous disease (CGD). As published recently in Science Translational Medicine, a team of NIH researchers has shown with the help of the latest CRISPR/Cas9 gene-editing tools, they can correct a mutation in human blood-forming adult stem cells that triggers a common form of CGD. What’s more, they can do it without introducing any new and potentially disease-causing errors to the surrounding DNA sequence [1].

When those edited human cells were transplanted into mice, the cells correctly took up residence in the bone marrow and began producing fully functional white blood cells. The corrected cells persisted in the animal’s bone marrow and bloodstream for up to five months, providing proof of principle that this lifelong genetic condition and others like it could one day be cured without the risks and limitations of our current treatments.

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Snapshots of Life: Portrait of a Bacterial Biofilm

Colony of Pseudomonas aeruginosa

Credit: Scott Chimileski and Roberto Kolter, Harvard Medical School, Boston

In nature, there is strength in numbers. Sometimes, those numbers also have their own unique beauty. That’s the story behind this image showing an intricate colony of millions of the single-celled bacterium Pseudomonas aeruginosa, a common culprit in the more than 700,000 hospital-acquired infections estimated to occur annually in the United States. [1]. The bacteria have self-organized into a sticky, mat-like colony called a biofilm, which allows them to cooperate with each other, adapt to changes in their environment, and ensure their survival.

In this image, the Pseudomonas biofilm has grown in a laboratory dish to about the size of a dime. Together, the millions of independent bacterial cells have created a tough extracellular matrix of secreted proteins, polysaccharide sugars, and even DNA that holds the biofilm together, stained in red. The darkened areas at the center come from the bacteria’s natural pigments.

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Built for the Future. Study Shows Wearable Devices Can Help Detect Illness Early

Michael Snyder wearing monitors

Caption: Stanford University’s Michael Snyder displays some of his wearable devices.
Credit: Steve Fisch/Stanford School of Medicine

Millions of Americans now head out the door each day wearing devices that count their steps, check their heart rates, and help them stay fit in general. But with further research, these “wearables” could also play an important role in the early detection of serious medical conditions. In partnership with health-care professionals, people may well use the next generation of wearables to monitor vital signs, blood oxygen levels, and a wide variety of other measures of personal health, allowing them to see in real time when something isn’t normal and, if unusual enough, to have it checked out right away.

In the latest issue of the journal PLoS Biology [1], an NIH-supported study offers an exciting glimpse of this future. Wearing a commercially available smartwatch over many months, more than 40 adults produced a continuous daily stream of accurate personal health data that researchers could access and monitor. When combined with standard laboratory blood tests, these data—totaling more than 250,000 bodily measurements a day per person—can detect early infections through changes in heart rate.

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Snapshots of Life: An Elegant Design

Collegen

Credit: David Sleboda and Thomas Roberts, Brown University, Providence, RI

Over the past few years, my blog has highlighted winners from the annual BioArt contest sponsored by the Federation of American Societies for Experimental Biology (FASEB). So, let’s keep a good thing going with one of the amazing scientific images that captured top honors in FASEB’s latest competition: a scanning electron micrograph of the hamstring muscle of a bullfrog.

That’s right, a bullfrog, For decades, researchers have used the American bullfrog, Rana catesbeiana, as a model for studying the physiology and biomechanics of skeletal muscles. My own early work with electron microscopy, as a student at Yale in the 1970s, was devoted to producing images from this very tissue. Thanks to its disproportionately large skeletal muscles, this common amphibian has played a critical role in helping to build the knowledge base for understanding how these muscles work in other organisms, including humans.

Revealed in this picture is the intricate matrix of connective tissue that holds together the frog’s hamstring muscle, with the muscle fibers themselves having been digested away with chemicals. And running diagonally, from lower left to upper right, you can see a band of fibrils made up of a key structural protein called collagen.

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Peanut Allergy: Early Exposure Is Key to Prevention

Kids and peanuts

Credit: Thinkstock (BananaStock, Kenishirotie)

With peanut allergy on the rise in the United States, you’ve probably heard parents strategizing about ways to keep their kids from developing this potentially dangerous condition. But is it actually possible to prevent peanut allergy, and, if so, how do you go about doing it?

There’s an entirely new strategy emerging now! A group representing 26 professional organizations, advocacy groups, and federal agencies, including the National Institutes of Health (NIH), has just issued new clinical guidelines aimed at preventing peanut allergy [1]. The guidelines suggest that parents should introduce most babies to peanut-containing foods around the time they begin eating other solid foods, typically 4 to 6 months of age. While early introduction is especially important for kids at particular risk for developing allergies, it is also recommended that high-risk infants—those with a history of severe eczema and/or egg allergy—undergo a blood or skin-prick test before being given foods containing peanuts. The test results can help to determine how, or even if, peanuts should be introduced in the youngsters’ diets.

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