New Mechanism for Rotavirus-Induced Diarrhea Uncovered

Researchers from Baylor College of Medicine have uncovered a novel mechanism through which rotavirus induces diarrhea, shedding light on potential avenues for future treatments. Published in Proceedings of the National Academy of Sciences, the study specifically identifies rotavirus-altered lipid metabolism as a significant factor in the development of gastroenteritis, a condition causing diarrhea, nutrient absorption deficiencies, and weight loss.

The study demonstrates that rotavirus infection leads to the degradation of DGAT1, an enzyme crucial for normal lipid droplet formation in intestinal cells. This degradation, in turn, reduces the production of essential nutrient transporters and other proteins necessary for normal intestinal nutrient absorption, resulting in diarrhea. The findings challenge previous assumptions about how rotavirus causes diarrhea, offering a new perspective on the role of altered lipid metabolism in the disease process.

According to co-corresponding author Sue E. Crawford, “We used the well-established monkey kidney cell (MA104) model of rotavirus infection as well as human intestinal enteroids (HIEs) for these studies. HIEs have revolutionized the study of gastrointestinal (GI) viruses like rotavirus. These multicellular, non-transformed cell cultures retain host genetic properties, cellular organization and recapitulate the function of the human gastrointestinal epithelium. They serve as biologically relevant model systems for studying human GI infections.”

Further exploration into DGAT1 revealed that children born with mutations rendering the enzyme nonfunctional experience severe chronic diarrhea, sometimes fatal. This observation led the researchers to hypothesize that rotavirus-mediated degradation of DGAT1 could be a key mechanism triggering diarrhea.

Contrary to the previously held belief that rotavirus induces diarrhea solely by infecting intestinal cells responsible for nutrient absorption, this study introduces a new paradigm. The degradation of DGAT1 by rotavirus results in reduced production of enzymes involved in degrading ingested food and disrupts mechanisms transporting nutrients into cells, ultimately leading to diarrhea.

The unexpected discovery of a rotavirus protein interacting with and degrading DGAT1 emphasizes the importance of considering nonstructural proteins in causing disease. This newfound understanding offers potential insights for the development of targeted treatments to mitigate the impact of rotavirus-induced gastroenteritis.