Research Roundup: Brain circuits for dominance, new HepC rodent model, eye repair in zebrafish and more

Welcome to this week’s Research Roundup. These Friday posts aim to inform our readers about the many stories that relate to animal research each week. Do you have an animal research story we should include in next week’s Research Roundup? You can send it to us via our Facebook page or through the contact form on the website.

  • Brain circuits for social dominance discovered. For humans and most other animals, a previous history of winning dictates continued social dominance. In a study recently published in Science, Zhou et al. may have found a neurological explanation for this “winner effect”. They show, using mice, that the dorsomedial prefrontal cortex (dmPFC) mediates behavior in a social conflict. Using optogenetic methods, researchers stimulated the dmPFC using light and found that this was sufficient to induce “winning” in mice tested on a task used to measure social dominance. Interestingly, this also worked in mice that were previously shown to be a “loser” when paired with another mouse in the task. If an analogous mechanism present in humans, this study could be of major importance in understanding various relevant psychiatric conditions associated with social behavior. This research was published in the journal Science.
  • New animal models for hepatitis C could pave the way for a vaccine. This discovery is a stepping stone towards the development of a vaccine for Hepatitis C which affects nearly 71 million people worldwide. Although there is now a cure for Hepatitis C, most people go undiagnosed leading to damage of the liver. Until now, an animal model was not available for vaccine development because hepatitis C is highly specific affecting only humans and chimpanzees. This breakthrough comes as a result of a collaborative effort with Ian Lipkin, a researcher at Columbia University, who was studying pathogens of common rats in New York City. He found a rat version of the hepatitis virus and after sharing his work with Dr. Charlie Rice, a researcher in virology at The Rockefeller University, they found a way to infect mice with the rat version of the virus. There are differences between the primate and rodent version of the virus but there is hope that “this research will help unravel mechanisms of liver infection, virus clearance, and disease mechanisms, which should prove valuable as we work to develop and test hepatitis C vaccines that can help to finally eradicate the disease around the world.” This study was published in Science.
Image courtesy of Rockefeller
  • A study in zebrafish found that the immune system controlled its ability to regenerate eye tissue. Researchers at John Hopkins are studying the ability of zebrafish to repair damaged eye retinal tissue using the regenerative response of Müller glia Having found that microglia, a type of cell involved in immune response, were the only cells able to penetrate the blood-retinal barrier, they prevented these cells from functioning, resulting in almost no regeneration from the Müller glia cells. A better understanding of this process could help scientists unlock human eye regeneration. Dr Jeffrey Mumm noted, “humans still have the genetic machinery needed to regenerate retinal tissue, if we can activate and control it.” This study was published in PNAS.
  • Early disruption of gut microbiota shapes later health. The gut microbiome plays an important role for health in humans and all living animals. In a recent study published in Nature Communications, researchers discovered that disruption of gut bacteria in frogs during the tadpole stage of maturation had negative effects on how adult frogs dealt with parasites. This effect may also be present in humans. Wherein, early-life disruption of human microbiota may stimulate the development of an under-reactive immune response to infections in adulthood.

  • Potential treatment for infants exposed to alcohol in utero identified. In the United States 1-5 percent of children are diagnosed with fetal alcohol spectrum disorder, which impairs learning, is linked to later-life behavioral problems, cardiovascular problems, and delayed development. In efforts to reverse these negative effects, scientists at Northwestern University treated rat pups, exposed to alcohol in utero, thyroxin or metaformin. Thyroxin is a hormone that is reduced in pregnant women that consume alcohol, and also in infants with fetal alcohol spectrum disorder. Metaformin is an insulin sensitizing drug that is found at higher concentrations in alcoholics. Both drugs reversed memory deficits, independently, as a consequence of in utero alcohol exposure. “We’ve shown you can interfere after the damage from alcohol is done. That’s huge,” said lead investigator and senior author Eva Redei. “We have identified a potential treatment for alcohol spectrum disorder. Currently, there is none.”The researchers are now looking for funding for clinical trials. This study was published in Molecular Psychiatry.