Research Roundup: Understanding How Sex Chromosomes are Regulated and More
Every week there are numerous scientific studies published. Here’s a look at some of the more interesting ones.
Better Understanding of How Sex Chromosome Genes Are Regulated
The sex chromosomes, X and Y, are different from the other 22 pairs of chromosomes in humans, in that only one is active per cell instead of two. Even in females, with two X chromosomes, one of them is inactive. Researchers at the Karolinska Institute have determined how cells double the expression of X-chromosome genes to balance out this change.
“The X chromosome generates ‘bursts’ of gene expression at a higher rate than other chromosomes, pointing to the involvement of special DNA elements called enhancers in maintaining an elevated X-chromosome expression,” said Bjorn Reinius, principal investigator at the Department of Medical Biochemistry and Biophysics at the Karolinska Institute.
In female cells, which have two X chromosomes, these bursts of gene expression on one X chromosome occurs in the same developmental window where the second X chromosome is inactivated. Some of these X chromosomes come from the father, others from the mother. Male cells carry only a single X chromosome, and the rhythm of gene expression is consistent through developmental phases and cell types.
“Failure to establish X chromosome dosage compensation during the early female embryogenesis is lethal and leads to early spontaneous abortion,” Reinius said. “With the new knowledge, we better understand how the cells’ gene expression network becomes destabilized.”
Advanced 3D Petri Dish to Grow Cancer Cells
Researchers at the University of Michigan have developed an advanced petri dish called a 3D scaffold that can allow the same cell growth and testing, but without the use of the lab animals and in a much shorter period. The researchers constructed a grid of microscale cubicles. Each cubicle was half a millimeter to a side. They then repeatedly exposed the cubicles to a solution of fibronectin with a tube that rotated end-over-end. The adhesion properties of the moving liquid drew the fibronectin into the fiber networks. They then tested the scaffold with culture cells taken from breast cancer patients whose disease had metastasized. The cancer cells in the samples were drawn from fluid in the abdomen and chest and made up only about 5% of cells in the fluids. But within only a few days the cancer cells dominated the cell population in the fibronectin network.
Obesity and Heart Failure—Understanding the Paradox
Obesity is well known for increasing the likelihood of developing heart failure. However, for people who have established heart failure, obesity may actually provide a survival benefit compared to individuals with normal weight or who are underweight, according to a new study. Researchers from the University of Adelaide pulled data from 375,056 patients in nine studies and found that the lowest mortality risk for patients with established heart failure (HF) was in people who were overweight. Although that is odd, and the correlation is not clear, the study also confirmed that obesity in people with no previous heart failure caused their risk to increase. Possible reasons for the paradox include earlier diagnosis in obese individuals as well as potentially obese patients tolerate disease-modifying and prognostic drugs compared to non-obese patients.
Havana Syndrome: Diplomats to Cuba Likely Affected by Pesticides
In 2017, Canadian and U.S. embassy staff began to complain of symptoms believed to be related to “acoustic attacks” by the Cuban government. This was dubbed “Havana Syndrome,” and the links to acoustic attacks were inconclusive. A new interdisciplinary study led by Alon Friedman of Ben-Gurion University of the Negev in Israel and Dalhousie University Brain Repair Center in Nova Scotia, Canada, suggests that Havana Syndrome was actually caused by overexposure to organophosphate insecticides.
The findings will be presented at Breaking the Barriers of Brain Science Symposium in New York on Sunday, October 27. The research was requested by Global Affairs Canada, who partnered with the Nova Scotia Health Authority. Friedman’s group at BGU and researchers from The Koren School of Veterinary Medicine at Hebrew University.
“We followed the science, and with each discovery we asked ourselves more questions,” Friedman said. “Pinpointing the exact location of where the brain was injured was an important factor that helped lead us to perform specific biochemical and toxicological blood tests and reach the conclusion that the most likely cause of the injury was repeated exposure to neurotoxins.”
Sleep to Learn Better
Perhaps not surprisingly, sleep patterns have a large effect on learning and memory. Researchers at the University of California, San Francisco (UCSF), working with rats, used a technique called optogenetics to decrease certain types of brain activity in sleeping rats. They identified two distinct forms of slow brain waves observed during sleep, called slow oscillations and delta waves. Slow oscillations strengthen the firing of specific brain cells involved in a newly learned skill; delta waves weaken the firing of these brain cells. In the case of the rats, the skill was how to operate a water spout they could control via a neural implant. The key finding is that a specific type of brain wave is linked to forgetting (or learning) a new concept.
How Do We See? New Findings.
Researchers determined the 3D structure of a protein complex involved in vision in vertebrates. This is involved in vision at atomic resolution and is believed to have broad implications for not only understanding biological signaling processes but could have an effect on more than a third of the drugs on the market. Signals from particles of light called photons are amplified in the eye. The research identified the 3D structure of a family of cell membrane proteins called G-protein-coupled receptors (GPCRs). They are involved in almost all biological processes in humans, including light, taste, smell, heart and muscle contraction.
Disease Protein Visualized for the First Time
Researchers at Oregon Health & Science University (OHSU) identified the 3D structure of a protein receptor, P2X7 receptor, that has been linked to inflammation, plaque buildup in arteries, cancer metastasis, neurological diseases and more. P2X7 behaves differently than many other receptors in that once it is activated, its channel remains open indefinitely. This allows charged particles to continually enter a cell and trigger the pathways for inflammation, which ultimately leads to cell death. This discovery may open the way to new approaches to treating diseases affected by the P2X7 receptor.