Recently, researchers from Monash University in Australia and utrecht university Medical Center in the Netherlands published a new study. They found a factor that triggered the proliferation and healing of muscle stem cells. In the mouse model of severe muscle injury, injecting this naturally occurring protein NAMPT can completely regenerate the muscle and restore normal movement after severe muscle injury. Related research results were published in the journal Nature.
In this study, the researchers studied the regeneration of skeletal muscle of zebrafish. Because zebrafish has a fast reproduction speed, it is easier to carry out experiments, and at least 70% of its genes are shared with humans, zebrafish has quickly become the first choice animal model for studying stem cell regeneration. Zebrafish is transparent, which makes it easier for scientists to observe the regeneration process in living muscles.
By studying the cells that migrated to the muscle injury of zebrafish, the researchers found a group of immune cells called macrophages, which seemed to play a role in triggering the regeneration of muscle stem cells. Macrophages are cells that gather in any injured or infected part of the body, removing debris and promoting healing. The researchers said that what they saw was that macrophages hugged muscle stem cells tightly, and then muscle stem cells began to divide and proliferate. Once they start this process, the macrophages will move on, then embrace the next muscle stem cell, and soon the wound will heal.
For a long time, people have always thought that there are two types of macrophages in the body: one is macrophages that move quickly to the injury and remove debris, and the other is macrophages that come slowly and stay around for a long time to clean up.
The study found that there are actually eight kinds of macrophages with different genes in the injured area, one of which is particularly "cute". Further investigation found that this emotional macrophage will release a substance called NAMPT. By removing these macrophages from zebrafish and adding NAMPT to aquarium water, the growth and healing of muscle stem cells can be stimulated, "effectively replacing the demand for macrophages".
Importantly, the recent experiment put the hydrogel patch containing NAPMT into a mouse model with severe muscle atrophy, which led to what researchers called a significant replacement of damaged muscles. At present, the research team is discussing with some biotechnology companies to introduce NAMPT into clinical trials in order to use this compound to treat muscle diseases and injuries.
Source of information:
[ 1]? Macrophages provide a temporary niche for muscle stem cells through NAMPT secretion [J]. China Neuroscience Press, 2002. Nature, 202 1, (2).