Intestinal epithelial barrier dysfunction, a hallmark of HIV/SIV infection, persists despite viral suppression by combination antiretroviral therapy (cART). Emerging evidence suggests a critical role for long noncoding RNAs (lncRNAs) in maintaining epithelial homeostasis. We simultaneously profiled lncRNA/mRNA expression exclusively in colonic epithelium (CE) of SIV-infected rhesus macaques (RMs) administered vehicle (VEH) or Δ-9-tetrahydrocannabinol (THC). Relative to controls, fewer lncRNAs were up- or downregulated in CE of THC/SIV compared with VEH/SIV RMs. Importantly, reciprocal expression of the natural antisense lncRNA MMP25-AS1 (up 2.3-fold) and its associated protein-coding gene MMP25 (attracts neutrophils by inactivating alpha-1 anti-trypsin/SERPINA1) (down 2.2-fold) was detected in CE of THC/SIV RMs. Computational analysis verified 2 perfectly matched complementary regions and an energetically stable (normalized binding free energy = –0.2626) MMP25-AS1/MMP25 duplex structure. MMP25-AS1 overexpression blocked IFN-γ–induced MMP25 mRNA and protein expression in vitro. Elevated MMP25 protein expression in CE of VEH/SIV but not THC/SIV RMs was associated with increased infiltration by myeloperoxidase/CD11b++ neutrophils (transendothelial migration) and epithelial CD47 (transepithelial migration) expression. Interestingly, THC administered in combination with cART increased MMP25-AS1 and reduced MMP25 mRNA/protein expression in jejunal epithelium of SIV-infected RMs. Our findings demonstrate that MMP25-AS1 is a potentially unique epigenetic regulator of MMP25 and that low-dose THC can reduce neutrophil infiltration and intestinal epithelial injury potentially by downregulating MMP25 expression through modulation of MMP25-AS1.

Background Although the advent of combination anti-retroviral therapy (cART) has transformed HIV into a manageable chronic disease, an estimated 30–50% of people living with HIV (PLWH) exhibit cognitive and motor deficits collectively known as HIV-associated neurocognitive disorders (HAND). A key driver of HAND neuropathology is chronic neuroinflammation, where proinflammatory mediators produced by activated microglia and macrophages are thought to inflict neuronal injury and loss. Moreover, the dysregulation of the microbiota–gut–brain axis (MGBA) in PLWH, consequent to gastrointestinal dysfunction and dysbiosis, can lead to neuroinflammation and persistent cognitive impairment, which underscores the need for new interventions. Methods We performed RNA-seq and microRNA profiling in basal ganglia (BG), metabolomics (plasma) and shotgun metagenomic sequencing (colon contents) in uninfected and SIV-infected rhesus macaques (RMs) administered vehicle (VEH/SIV) or delta-9-tetrahydrocannabinol (THC) (THC/SIV). Results Long-term, low-dose THC reduced neuroinflammation and dysbiosis and significantly increased plasma endocannabinoid, endocannabinoid-like, glycerophospholipid and indole-3-propionate levels in chronically SIV-infected RMs. Chronic THC potently blocked the upregulation of genes associated with type-I interferon responses ( NLRC5 , CCL2 , CXCL10 , IRF1 , IRF7 , STAT2 , BST2 ), excitotoxicity ( SLC7A11 ), and enhanced protein expression of WFS1 (endoplasmic reticulum stress) and CRYM (oxidative stress) in BG. Additionally, THC successfully countered miR-142-3p-mediated suppression of WFS1 protein expression via a cannabinoid receptor-1-mediated mechanism in HCN2 neuronal cells. Most importantly, THC significantly increased the relative abundance of Firmicutes and Clostridia including indole-3-propionate ( C. botulinum , C. paraputrificum , and C. cadaveris ) and butyrate ( C. butyricum , Faecalibacterium prausnitzii and Butyricicoccus pullicaecorum ) producers in colonic contents. Conclusion This study demonstrates the potential of long-term, low-dose THC to positively modulate the MGBA by reducing neuroinflammation, enhancing endocannabinoid levels and promoting the growth of gut bacterial species that produce neuroprotective metabolites, like indole-3-propionate. The findings from this study may benefit not only PLWH on cART, but also those with no access to cART and more importantly, those who fail to suppress the virus under cART.

Background HIV/SIV-associated periodontal disease (gingivitis/periodontitis) (PD) represents a major comorbidity affecting people living with HIV (PLWH) on combination anti-retroviral therapy (cART). PD is characterized by chronic inflammation and dysbiosis. Nevertheless, the molecular mechanisms and use of feasible therapeutic strategies to reduce/reverse inflammation and dysbiosis remain understudied and unaddressed. Methods Employing a systems biology approach, we report molecular, metabolome and microbiome changes underlying PD and its modulation by phytocannabinoids [delta-9-tetrahydrocannabinol (Delta(9)-THC)] in uninfected and SIV-infected rhesus macaques (RMs) untreated (VEH-untreated/SIV) or treated with vehicle (VEH/SIV) or Delta(9)-THC (THC/SIV). Findings VEH- untreated/SIV but not THC/SIV RMs showed significant enrichment of genes linked to anti-viral defense, interferon-beta, NF kappa B, RIG-1, and JAK-STAT signaling. We focused on the anti-microbial DUOX1 and immune activation marker IDO1 that were reciprocally regulated in the gingiva of VEH-untreated/SIV RMs. Both proteins localized to the gingival epithelium and CD163(+) macrophages, and showed differential expression in the gingiva of THC/SIV and VEH/SIV RMs. Additionally, inflammation-associated miR-21, miR-142-3p, miR-223, and miR-125a-5p showed significantly higher expression in the gingiva of VEH/SIV RMs. In human primary gingival epithelial cells, miR-125a-5p post-transcriptionally downregulated DUOX1 and THC inhibited IDO1 protein expression through a cannabinoid receptor-2 mediated mechanism. Interestingly, THC/SIV RMs showed relatively reduced plasma levels of kynurenine, kynurenate, and the neurotoxic quinolinate compared to VEH/SIV RMs at 5 months post SIV infection (MPI). Most importantly, THC blocked HIV/SIV-induced depletion of Firmicutes and Bacteroidetes, and reduced Gammaproteobacteria abundance in saliva. Reduced IDO1 protein expression was associated with significantly (p<0.05) higher abundance of Prevotella, Lactobacillus (L. salivarius, L. buchneri, L. fermentum, L. paracasei, L. rhamnosus, L. johnsonii) and Bifidobacteria and reduced abundance of the pathogenic Porphyromonas cangingivalis and Porphyromonas macacae at 5MPI. Interpretation The data provides deeper insights into the molecular mechanisms underlying HIV/SIV-induced PD and more importantly, the anti-inflammatory and anti-dysbiotic properties of THC in the oral cavity. Overall, these translational findings suggest that phytocannabinoids may help reduce gingival/systemic inflammation, salivary dysbiosis and potentially metabolic disease/syndrome in PLWH on cART and those with no access to cART or do not suppress the virus under cART. Copyright (C) 2021 The Authors. Published by Elsevier B.V.