If obesity seems to be spreading like a virus, that could be because it is. We鈥檙e now closer to understanding how adenovirus-36 (Ad-36), thought to be responsible for some cases of obesity, causes fat cells to grow.
Last year Nikhil Dhurandhar at Louisiana State University at Baton Rouge showed that Ad-36 causes precursor cells to differentiate into fat cells, and could promote obesity in humans and animals. Now he has shown that a single viral gene is responsible for triggering this process, meaning that one day it may be possible to treat 鈥渧iral obesity鈥� by altering the action of that gene.
Dhurandhar鈥檚 team engineered stem cells from human fat to express a single gene from Ad-36, called E4 ORF-1. The cells were much more likely to differentiate into fat cells than those that did not express the gene. When they blocked expression of E4 ORF-1 in cells infected by Ad-36, the cells failed to differentiate into fat cells 鈥� proof that this gene is both necessary and sufficient for fat cell differentiation (International Journal of Obesity, ). Researchers may someday be able to block E4 ORF-1 in humans to prevent Ad-36-induced obesity, he says.
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The gene also makes cells more responsive to insulin, so drugs that mimic this part of the gene鈥檚 action may also be useful in treating type 2 diabetes. Hopefully they鈥檒l find a way to tease out this part of the gene鈥檚 action from the fat-promoting part.
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