Cool Videos: Patching and Sealing the Cell Membrane

Cell Repair Video

Bill Bement describes himself as a guy who “passionately, obsessively, and almost feverishly” loves to study cells. His excitement comes through in our final installment of the American Society for Cell Biology’s Celldance 2014. Bement, an NIH grantee at the University of Wisconsin, Madison, shares his scanning confocal microscope with us for this fascinating glimpse into the rapid response of cells to repair holes, tears, and other structural damage in their protective outer membranes.

For most people, this damage response runs on biochemical autopilot, sealing any membrane break within seconds to keep the cell viable and healthy. But some people inherit gene mutations that make sealing and patching difficult, particularly in cells that operate under repetitive mechanical stress. For example, some forms of muscular dystrophy stem specifically from an inherited inability to repair breaks in the cell membrane of skeletal muscle cells. In one type of disease that affects both skeletal and cardiac muscle, a gene mutation alters the shape of a protein called dysferlin, which normally binds annexin proteins that, as noted in the video, play a vital role in patching holes. In the presence of a glitch in dysferlin, the rapid chain of biochemical events needed to enable such repair breaks down.

There’s still an enormous amount to learn about cell membrane repair, so it will be interesting to see what Bement’s microscope and camera will show us next.

Links:

Bement Lab, University of Wisconsin-Madison

Celldance 2014, American Society for Cell Biology

NIH Support: National Institute of General Medical Sciences

Clot Removal: Impressive Results for Stent Retrievers in Acute Stroke

Schematic of clot retriever

Caption: Schematic of how the clot retriever used in the reported trials is opened inside a blood vessel to surround a clot that is blocking blood flow. Once caught by the stent, the entire apparatus with the clot is removed from the body out a small puncture in the femoral artery at the groin.
Credit: Covidien

Despite the recent progress we’ve made in preventing stroke by such steps as controlling weight, lowering blood pressure, and stopping smoking, nearly 700,000 Americans suffer clot-induced, or ischemic, strokes every year [1]. So, I’m very pleased to report that, thanks to years of rigorous research and technological development, we’ve turned a major corner in the emergency treatment of this leading cause of death and disability.

The most severe strokes—those that can cause lifelong loss of independent function—are often due to blood clots that suddenly enter and block one of the main arteries supplying blood flow to the brain. No less than four large, randomized clinical trials recently reported results showing, for the first time, that using catheters to remove large clots from cerebral arteries can restore blood flow and halt further damage to the brains of patients with acute strokes. In fact, the stent-based retrievers and other mechanical approaches used to remove stroke-causing clots proved so effective, that three of the four trials were stopped early, allowing the results to be made swiftly available to medical professionals and the public.

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Shattering News: How Chromothripsis Cured a Rare Disease

Karyotype

Caption: Karyotype of a woman spontaneously cured of WHIM syndrome. These chromosome pairings, which are from her white blood cells, show a normal chromosome 2 on the left, and a truncated chromosome 2 on the right.
Source: National Institute of Allergy and Infectious Diseases , NIH

The world of biomedical research is filled with surprises. Here’s a remarkable one published recently in the journal Cell [1]. A child born in the 1950s with a rare genetic immunodeficiency syndrome amazingly cured herself years later when part of one of her chromosomes spontaneously shattered into 18 pieces during replication of a blood stem cell. The damaged chromosome randomly reassembled, sort of like piecing together a broken vase, but it was still missing a shard of 164 genes—including the very gene that caused her condition.

Researchers say the chromosomal shattering probably took place in a cell in the bone marrow. The stem cell, now without the disease-causing gene, repopulated her immune system with healthy bone marrow-derived immune cells, resulting in cure of the syndrome.

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Peanut Allergies: Prevention by Early Exposure?

Peanuts and peanut products

Credit: United States Department of Agriculture

It might seem obvious that the best way to avoid a food allergy is to steer clear of the offending item. But a recent study, published in the New England Journal of Medicine, suggests that just the opposite may be true: strict avoidance from a very early age may be the wrong strategy when it comes to kids at high risk of developing an allergy to peanuts [1].

The study found that feeding peanut-rich foods to some high-risk infants actually helps their developing immune systems learn to tolerate peanuts better, apparently helping them avoid this serious allergy later in life. While it’s too soon to recommend stepping up peanut consumption among all babies, the findings provide striking new insights into how food allergies develop and how they might be avoided.

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Lessons from a High School Student: Motivation + Perseverance = Success

Emily Ashkin Video

It may surprise you to learn that the poised young woman featured in this video was a sophomore in high school at the time the film was made. Today, Emily Ashkin is a high school senior with impressive laboratory experience and science awards to her name.  As it happens, she’s also introducing me when I deliver a keynote address at the Melanoma Research Alliance’s annual scientific meeting — today, here in Washington, D.C.

What struck me most when I heard Emily’s story was her fearlessness. When mentoring young students, helping some to believe in themselves can be a real challenge. Not Emily. She faces her challenges by seeking solutions, asking—as she does in the video—“Why can’t that be me?”

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