Origin of fat build up in muscle

An insight into the build up of fatty tissue in damaged muscle is published online in two papers in Nature Cell Biology this week. This fat deposition is associated with disorders such as muscular dystrophy and the research may have therapeutic relevance for future treatments into such disorders.

Healthy muscle regeneration is dependent on responses of multiple cell types, including satellite cells ― known as adult muscle stem cells. Akiyoshi Uezumi and colleagues identify a population of progenitors, distinct from satellite cells, which are responsible for the formation of fatty tissue both in cell culture and in mice. These cells ― PDGFRalpha+ ― are inhibited by healthy muscle cells, but proliferate when transplanted into mouse damaged muscles.

In a related paper Fabio Rossi and colleagues also identify a population of fat forming progenitors that reside in muscle tissue. Using transplantation they show that these progenitors generate fatty tissue when delivered into damaged, but not healthy muscle in mice. These cells are not directly involved in repair, but can stimulate restoration of muscle function.

The researchers believe that targeting these fat progenitors may open new opportunities for designing therapeutic strategies to reducing scarring and treat muscle diseases.