Chronic Administration of Δ ⁹ -Tetrahydrocannabinol Induces Intestinal Anti-Inflammatory MicroRNA Expression during Acute Simian Immunodeficiency Virus Infection of Rhesus Macaques

Abstract

Gastrointestinal (GI) tract disease/inflammation is a hallmark of HIV/SIV infection. Previously, we showed that chronic treatment of SIV-infected macaques with Δ9-tetrahydrocannabinol (Δ9-THC) increased survival and decreased viral replication and infection-induced gastrointestinal inflammation. Here, we show that chronic THC administration to SIV-infected macaques induced an anti-inflammatory microRNA expression profile in the intestine at 60 days p.i. These included several miRNAs bioinformatically predicted to directly target CXCL12, a chemokine known to regulate lymphocyte and macrophage trafficking into the intestine. Specifically, miR-99b was significantly upregulated in THC-treated SIV-infected macaques and confirmed to directly target NADPH oxidase 4 (NOX4), a reactive oxygen species generator known to damage intestinal epithelial cells. Elevated miR-99b expression was associated with a significantly decreased number of NOX4+ epithelial cells in the intestines of THC-treated SIV-infected macaques. Overall, our results show that selective upregulation of anti-inflammatory miRNA expression contributes to THC-mediated suppression of gastrointestinal inflammation and maintenance of intestinal homeostasis.