Certain organisms have remarkable abilities to achieve self-healing, and a fascinating example is the zebrafish (Danio rerio), a species of tropical freshwater fish that’s an increasingly popular model organism for biological research. When the fish’s spinal cord is severed, something remarkable happens that doesn’t occur in humans: supportive cells in the nervous system bridge the gap, allowing new nerve tissue to restore the spinal cord to full function within weeks.
Pretty incredible, but how does this occur? NIH-funded researchers have just found an important clue. They’ve discovered that the zebrafish’s damaged cells secrete a molecule known as connective tissue growth factor a (CTGFa) that is essential in regenerating its severed spinal cord. What’s particularly encouraging to those looking for ways to help the 12,000 Americans who suffer spinal cord injuries each year is that humans also produce a form of CTGF. In fact, the researchers found that applying human CTGF near the injured site even accelerated the regenerative process in zebrafish. While this growth factor by itself is unlikely to produce significant spinal cord regeneration in human patients, the findings do offer a promising lead for researchers pursuing the next generation of regenerative therapies.
Tags: connective tissue growth factor a, CTGF, Danio rerio, fish, glia, glial bridges, glial cells, growth factor, model organisms, nerve cells, nervous system, regenerative medicine, self-healing, spinal cord, spinal cord injuries, tissue engineering, tissue regeneration, traumatic injury, wound healing, zebrafish
What happens when you implant human glia—a type of brain cell that protects and nurtures neurons—into the brains of newborn mice? Well, it turns out these glia mature into multi-talented astrocyte cells that provide nutrients, repair injuries, and modulate signals just like they do in a human brain. They even assume the same complex star shape!
We know the cells in question are indeed human astrocytes because they produce a group of specific proteins, which are tagged with a combination of dyes that together appear yellow in this image. In contrast, the mouse cells are blue.
This all looks very pretty, but you might wonder what impact these human astrocytes have on mouse cognition. Researchers found mice that received the implants were better able to learn and remember than those that didn’t. In short, the human cells seem to have made the mice smarter.
Interestingly, human astrocytes are larger, more complex, and more diverse than their counterparts in other species. So, perhaps these cells may hold some of the keys to our own unique cognitive abilities.
Forebrain Engraftment by Human Glial Progenitor Cells Enhances Synaptic Plasticity and Learning in Adult Mice. Xiaoning Han, Michael Chen, Fushun Wang, Martha Windrem, Su Wang, Steven Shanz, Qiwu Xu, Nancy Ann Oberheim, Lane Bekar, Sarah Betstadt, Alcino J. Silva, Takahiro Takano, Steven A. Goldman, and Maiken Nedergaard. Cell Stem Cell 12, 342–353, March 7, 2013.
NIH support: the National Institute of Mental Health; and the National Institute of Neurological Disorders and Stroke
Posted In: Science