Diet and insulin in a stem cell niche Hormonal signaling in the fruit fly
Insulin reverses the effects of aging and poor diet, at least on cells within the ovaries of fruit flies. Biologists Daniela Drummond-Barbosa and Hwei-Jan Hsu of Vanderbilt University in Nashville, Tennessee, found that boosting levels of insulin-like peptides slowed down the decline in stem cell numbers and function that normally occurs as flies age. The hormone does not act on the stem cells directly, but rather via the niche — the cells that form a stem cell's support system. Hormones probably influence most niches, though surprisingly little is known about it, says Erika Matunis of John Hopkins University in Baltimore, Maryland, who studies how stem cells maintain sperm production in fruit flies and was not involved in the study. "At this point the fly ovary is yielding by far the most detailed glimpse into the interactions of hormonal signaling and stem cell niches." "Normally, a lot of research on niches is concentrated on local factors produced by the niche that affect stem cells," says Drummond-Barbosa. "In this paper, we take a broader view to understand how these local microenvironments can be impacted by the environment where the organism lives."