Opioid-induced protein coding and noncoding transcriptome of human CD8+ T cells reveals opioid receptor subclass specific responses

Abstract

Abstract Opioid peptides are released at sites of injury; their cognate G-protein coupled opioid receptors (OR) are expressed on immune cells. Conflicting reports attribute immunostimulatory and immunosuppressive activity to opioids. From a cohort of methadone patients and controls, we found that chronic opioid use disrupts CD8+ T cell subset balance, via decreased T Effector Memory RA+ cells. Exposure of CD8+ T cells ex vivo to a μ-OR or δ-OR agonist differentially regulates thousands of protein coding genes. Gene set enrichment analysis reveals that μ-OR more strongly regulates cellular processes, including immune response via interferon, IL-2, and mTOR signaling pathways. A striking finding is the linkage of μ-OR, but not δ-OR, signaling to the upregulation of lipid, cholesterol, and steroid biosynthesis. OR-specific gene signatures associate with different transcription factors, supporting our hypothesis that transcriptional regulation underlies cellular outcomes ascribed to individual ORs. The noncoding transcriptome of opioid exposed cells is largely unique to each OR; μ-OR regulates 53 long noncoding RNAs, while δ-OR regulates 59, with only three shared transcripts, one of which is inversely regulated. The noncoding RNA upregulated by both ORs enhances integrin expression and binding; the noncoding RNA downregulated by both ORs represses STAT signaling and apoptosis. Comparison of CD4 vs. CD8 T cell responses to ligation of all three ORs (μ, δ, κ) reveals lineage specific regulation of TNF-signaling and fatty acid metabolism in response to μ-OR, G protein and cytokine receptor signaling in response to δ-OR, and REDOX pathways in response κ-OR, indicating that opioid induced immune regulation is both cell type and OR specific.