Alterations in the gut microbiota associated with HIV-1 infection

Catherine A. Lozupone, Marcella Li, Thomas B. Campbell, Sonia C. Flores,

Derek Linderman, Matthew J. Gebert, Rob Knight, Andrew P. Fontenot, and Brent E. Palmer

Cell Host & Microbe 14, 329–339

Speaker: Yi-Ching, Chiu (邱意晴)                   Time: 13:00~ 14:00, Nov.19, 2014

Commentator: Shainn-Wei Wang (王憲威 教授)       Place: Room 601

Abstract:

Human immunodeficiency virus (HIV) is a lentivirus that causes the acquired immunodeficiency syndrome (AIDS). HIV-1 infection induces serious damage to gut- associated lymphoid tissues (GALTs), with massive depletion of Th17 cells that control intestinal bacteria. [1] In healthy individuals, intestinal bacteria play an important role in the immune system, performing a barrier effect. The authors in this study wanted to investigate how microbiota composition alters with HIV infection , immunologic driving factors of these differences, and their implication for gut- linked disease that increase in prevalence with HIV. At first, the authors performed 16S rRNA sequencing of feces, and showed that HIV infection was associated with highly characteristic changes in the gut community structure and that antiretroviral therapy (ART) did not consistently restore the microbiota to an HIV- negative like state. Results of statistical analysis indicated that the fecal microbiota of untreated individuals with chronic infection exhibited significantly higher relative abundances of Prevotella and decrease in Bacteroides. Based on this finding, the authors combined their data with data from (1) a survey of fecal microbiota in individuals from Malawi, Venezuela, and the U.S. and (2) a study linking long- term dietary pattern in healthy U.S. adults with Bacteroides- versus Prevotella – rich enterotypes. The results showed that samples from the U.S. clustered closer to individuals from Malawi and Venezuelan Amerindians than to HIV- negative individuals from the U.S. Furthermore, the authors wanted to explore the relationship between immune dysfunction and HIV- associated microbiota change, so they compared T cell proliferation and cytokine responses to lysates from bacteria that differ with HIV infection in blood from HIV- positive and – negative individuals. In conclusion, the different disease states, culture, and diet can participate in the changes of gut microbiota composition with HIV infection. Therefore, further studies of the immune- modulatory properties and inflammation tolerance of bacterial communities that change during HIV infection will provide insight into driving factors of gut microbiota changes and their potential impact on health.

Reference:

1. Brenchley, J.M., Schacker, T.W., Ruff, L.E., Price, D.A., Taylor, J.H., Beilman, .J., Nguyen, P.L., Khoruts, A., Larson, M., Haase, A.T., and Douek, D.C. (2004). CD4+ T cell depletion during all stages of HIV disease occurs predominantly in the gastrointestinal tract. J. Exp. Med. 200, 749–759.