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Archive - Oct 2020

October 1st

Cryptic Exon Discovered in Sry Gene on Y-Chromosome in Mice Is Critical for Male Sex Development; Finding May Enable Selection for the Desired Sex in Agricultural Industries Such As Dairy (Females) or Beef (Males)

An international research collaboration among researchers at the University of Queensland, Osaka University, and Tokushima University. has found that the Y-chromosome gene that makes mice male is made up of two different DNA parts, not one, as scientists had previously assumed. UQ's Institute of Molecular Biosciences Emeritus Professor Peter Koopman, PhD, said the critical DNA fragment had been hidden from researchers for more than 30 years. "Expression of the Y chromosomal gene Sry (sex-determining region Y) is required for male development in mammals and since its discovery in 1990 has been considered a one-piece gene," Dr. Koopman said. "Sry turns out to have a cryptic second part, which nobody suspected was there, that is essential for determining the sex of male mice. We have called the two-piece gene Sry-T." The scientists tested their theory and found that male mice (XY) lacking in Sry-T developed as female, while female mice (XX) carrying a Sry-T transgene developed as male. The success rate for the experiments was almost 100 per cent. The results were reported in the October 2, 2020 issue of Science. The article is titled “The Mouse Sry Locus Harbors a Cryptic Exon That Is Essential for Male Sex Determination.” Dr. Koopman said the discovery would change how basic biology and evolution is taught around the world. "For the last 30 years, we've been trying to figure out how this works," he said. "Sry is a master switch gene because it flicks the switch for male development, it gets the ball rolling for a whole series of genetic events that result in a baby being born as a male instead of female. This new piece of the gene is absolutely essential for its function; without that piece, the gene simply doesn't work.

September 30th

Exosome Treatment Improves Recovery from Heart Attacks in Pig Model

Science has long known that recovery from experimental heart attacks is improved by injection of a mixture of heart muscle cells, endothelial cells, and smooth muscle cells, yet results have been limited by poor engraftment and retention, and researchers worry about potential tumorigenesis and heart arrhythmia. Now, research in pigs shows that using the exosomes naturally produced from that mixture of heart muscle cells, endothelial cells, and smooth muscle cells--which were all derived from human induced pluripotent stem cells (hiPSCs)--yields regenerative benefits equivalent to the injected human induced pluripotent stem cell-cardiac cells, or hiPSC-CCs. Exosomes are sub-cellular, cell-released, membrane-bound extracellular vesicles (EVs) that can contain biologically active proteins, RNAs, and microRNAs. Exosomes are well known to participate in cell-to-cell communication, and they are actively studied as potential clinical therapies. “The hiPSC-CC exosomes are acellular and, consequently, may enable physicians to exploit the cardioprotective and reparative properties of hiPSC-derived cells while avoiding the complexities associated with tumorigenic risks, cell storage, transportation, and immune rejection,” said Ling Gao, PhD, and Jianyi “Jay” Zhang (photo), MD, PhD, University of Alabama at Birmingham (UAB), corresponding authors of the study, published online on September 16, 2020 in Science Translational Medicine. “Thus, exosomes secreted by hiPSC-derived cardiac cells improved myocardial recovery without increasing the frequency of arrhythmogenic complications and may provide an acellular therapeutic option for myocardial injury.” The article is titled “Exosomes Secreted by hiPSC-Derived Cardiac Cells Improve Recovery From Myocardial Infarction In Swine.” At UAB, Dr.

Scientists Trace 13.5% of Severe COVID-19 to Auto-Antibodies Against Type I Interferons or Mutations in Type I Interferon Genes

More than 10 percent of people who develop severe COVID-19 have misguided antibodies that attack not the virus, but the immune system itself, new research shows. Another 3.5 percent, at least, carry a specific kind of genetic mutation. In both groups, the upshot is basically the same: The patients lack type I interferons, a set of 17 proteins crucial for protecting cells and the body from viruses. Whether the proteins have been neutralized by so-called auto-antibodies, or were not produced in sufficient amounts in the first place due to a faulty gene, their missing-in-action appears to be a common theme among a subgroup of COVID-19 sufferers whose disease has thus far been a mystery. Published online on September 24, 2020 in two papers in Science, the findings help explain why some people develop a disease much more severe than others in their age group—including, for example, individuals who required admission to the ICU despite being in their 20s and free of underlying conditions. The findings may also provide the first molecular explanation for why more men than women die from the disease. The two open-access Science articles are “Auto-Antibodies Against Type I IFNs in Patients with Life-Threatening COVID-19” (https://science.sciencemag.org/content/early/2020/09/23/science.abd4585) and “Inborn Errors of Type I IFN Immunity in Patients with Life-Threatening COVID-19” (https://science.sciencemag.org/content/early/2020/09/29/science.abd4570). “These findings provide compelling evidence that the disruption of type I interferon is often the cause of life-threatening COVID-19,” says Jean-Laurent Casanova, MD, PhD, Head of the St.