Changes in brain chemistry sustain obesity
Brown University and Lifespan researchers reported in The Journal of Biological Chemistry that a study of the brain cells of rats revealed that obesity restricts production of a hormone that curbs appetite and spurs calorie burning. In the brain, the levels of a key enzyme called PC2 are decreased because of endoplasmic reticulum stress. The role of PC2 is to process pro-opiomelanocortin into alpha-MSH (among other biochemical compounds), a hormone involved in suppressing food-seeking behaviors and in stimulating TRH production, consequently promoting a calorie-burning metabolism. When treated with TUDCA, a chemical known to alleviate ER stress, the team’s obese mice experienced a marked increase in alpha-MSH. Similarly, lean mice pretreated with PBA, a substance preventing ER stress, produced twice as much PC2 when obesity was induced than mice without the treatment.
A step closer to artificial livers
Sangeeta Bhatia, a Massachusetts Institute of Technology researcher whose team is working to make the creation of functional livers in laboratory settings possible, reported in the June issue of the journal Nature Chemical Biology the chemical compounds the team discovered to help liver cells maintain function outside the human body and to induce pluripotent stem cells to mature more completely. The team experimented on a system previously proved to maintain liver cells temporarily, adapting it to make them grow in small depressions with layers of fibroblast cells. The researchers used thousands of different substances and eventually identified 12 compounds that helped liver cells maintain their functionality, promoted their division or did both. The researchers say this work may prove to be an important step in finding a cure for many chronic liver diseases, such as hepatitis C.
Scientists to trial synthetic blood in humans
Researchers at the Scottish Centre for Regenerative Medicine have been granted the first license to test in humans a synthetic blood, which they made using stem cells. The researchers in the past have used embryonic stem cells, but they now want to use induced pluripotent stem cells from adults. This new approach would help scientists produce all blood types by selecting the appropriate donor samples from which to produce the cell lines. Project leader Marc Turner, director of the Scottish National Blood Transfusion Service, said, “We hope that in the next two to three years we will be putting together the kind of manufacturing capability and also the regulatory and quality requirements to start clinical studies.” Experts say the approach could help address immense blood shortages worldwide.
Brain is command center for aging
A team at the Albert Einstein College of Medicine may have identified a key player in the aging process. It appears that the inflammatory protein nuclear factor κB (NF-κB) in the hypothalamus becomes increasingly active in mice as they become older, leading to aging-related changes. By controlling the levels of the upstream activator IKK-β, the researchers were able to study the effects of NF-κB, among which is the suppression of the gonadotropins-releasing hormone (GnRH). They also found that GnRH is involved in promoting adult neurogenesis, and mice that were injected with it had fewer signs of aging. The study was published in the journal Nature in early May.
Two unexpected helpers aid muscle repair after injury
Eosinophils and fibro/adipogenic cells (FAP) collaborate to help muscular tissue regenerate after injury, University of California, San Francisco, scientists recently reported. FAP cells are progenitor cells previously known for making adipose and connective tissue. It appears that when exposed to IL-4, an interleukin produced by local eosinophils, FAP cells proliferate and stimulate muscle stem cells to generate muscle fibers. The researchers found that eosinophils are responsible for the clearance of necrotic fibers as well, despite the previous belief that this process involved macrophages. “Without eosinophils, you cannot regenerate muscle,” said Ajay Chawlaan, an associate professor at the UCSF Cardiovascular Research Institute, who oversaw the study. The finding was published in the journal Cell in April.
Hundreds of tiny untethered surgical tools deployed in first animal biopsies
Engineers and physicians at Johns Hopkins University might have found a way to make biopsies, the gold standard in the diagnosis of cancer and various other diseases, more efficient. The team devised specialized tools called mu-grippers that can be put through natural orifices to reach rather inaccessible places and retrieve a wide variety of samples. The devices are submillimetric and fabricated through photolithography with fingerlike projections that naturally curl inward. The digits are straightened by a polymer resin and kept on ice prior to the intervention so that, when they reach the warm temperature of the area targeted for a biopsy, the polymer coating softens and the projections return to their natural shape and grasp the tissue. Made of magnetic materials, they are then retrieved using a magnetic catheter. The scientists successfully retrieved bioptic samples from living animals, with results published in two journals, Gastroenterology and Advanced Materials, earlier this year.
Adult stem cells could hold key to curing type 1 diabetes
A key step in the pathogenesis of type 1 diabetes has been discovered by Habib Zaghouani and his research team at the Missouri University School of Medicine. After developing a drug called Ig-GAD2 to stop the autoimmune attack against pancreatic beta cells, the team found that the number of salvageable cells was too small, so they had to find another way to reverse the disease. They stimulated beta cell regeneration by injecting adult stem cells from the bone marrow into the pancreas. The combination of this and Ig-GAD2 treatment led to the desired effect but in a surprising way. It appears the stem cells led to neoangiogenesis, which facilitated the reproduction of beta cells. “In other words, we discovered that to cure type 1 diabetes, we need to repair the blood vessels that allow the subject’s beta cells to grow and distribute insulin throughout the body,” Zaghouani said. Details can be found in the May issue of the journal Diabetes.
This news roundup was compiled by ASBMB Today contributor Teodora Donisan (firstname.lastname@example.org), a medical student at Carol Davila University in Bucharest, Romania. Send links of interest to email@example.com for possible inclusion in future issues.