Chronic Ethanol Consumption Modulates Growth Factor Release, Mucosal Cytokine Production, and MicroRNA Expression in Nonhuman Primates

Abstract

BACKGROUND Chronic alcohol consumption has been associated with enhanced susceptibility to both systemic and mucosal infections. However, the exact mechanisms underlying this enhanced susceptibility remain incompletely understood. METHODS Using a nonhuman primate model of ethanol self-administration, we examined the impact of chronic alcohol exposure on immune homeostasis, cytokine and growth factor production in peripheral blood, lung and intestinal mucosa following twelve months of chronic ethanol exposure. RESULTS Ethanol exposure inhibited activation-induced production of growth factors HGF, G-CSF and VEGF by peripheral blood mononuclear cells (PBMC). Moreover, ethanol significantly reduced the frequency of colonic Th1 and Th17 cells in a dose-dependent manner. In contrast, we did not observe differences in lymphocyte frequency or soluble factor production in the lung of ethanol-consuming animals. To uncover mechanisms underlying reduced growth factor and Th1/Th17 cytokine production, we compared expression levels of microRNAs in PBMC and intestinal mucosa. Our analysis revealed ethanol-dependent upregulation of distinct microRNAs in affected tissues (miR-181a and miR-221 in PBMC; miR-155 in colon). Moreover, we were able to detect reduced expression of the transcription factors STAT3 and ARNT, which regulate expression of VEGF, G-CSF and HGF and contain targets for these microRNAs. To confirm and extend these observations, PBMC were transfected with either mimics or antagomirs of miR181 and 221and protein levels of the transcription factors and growth factors were determined. Transfection of microRNA mimics led to a reduction in both STAT-3/ARNT as well as VEGF/HGF/G-CSF levels. The opposite outcome was observed when microRNA antagomirs were transfected CONCLUSION Chronic ethanol consumption significantly disrupts both peripheral and mucosal immune homeostasis, and this dysregulation may be mediated by changes in microRNA expression.

Combined Whole Methylome and Genomewide Association Study ImplicatesCNTN4in Alcohol Use

“…STAT3 has a role in regulating synaptic plasticity in the central nervous system (Nicolas et al, 2013). Notably, reduced expression of STAT3 has been shown in peripheral blood of non-human primates following chronic ethanol consumption (Asquith et al, 2014). The overlap of the region of interest with TF binding sites suggests a potential mechanism by which methylation may influence alcohol use.…”

Opposing effects of alcohol on the immune system

“…The reduced production of growth factors in this nonhuman primate model of ethanol self-administration was due to increased expression of microRNA miR-181 and miR-221, which led to reduced expression of the transcription factors, signal transducer and activator of transcription 3 (STAT3) and aryl hydrocarbon receptor nuclear translocator (ARNT) (Asquith, Pasala et al 2013). …”

“…Finally, in a nonhuman primate model of ethanol self-administration (Grant et al 2008), PMA-induced production of the growth factors hepatocyte growth factor (HGF), granulocyte colony-stimulating factor (G-CSF), and vascular-endothelial growth factor (VEGF) by peripheral blood mononuclear cells (PBMCs) isolated from male and female rhesus macaques after 12 months of chronic ethanol exposure were inhibited (Asquith, Pasala et al 2013). The reduced production of growth factors in this nonhuman primate model of ethanol self-administration was due to increased expression of microRNA miR-181 and miR-221, which led to reduced expression of the transcription factors, signal transducer and activator of transcription 3 (STAT3) and aryl hydrocarbon receptor nuclear translocator (ARNT) (Asquith, Pasala et al 2013).…”

Cytokine/Chemokine Responses in Activated CD4+and CD8+T Cells Isolated from Peripheral Blood, Bone Marrow, and Axillary Lymph Nodes during Acute Simian Immunodeficiency Virus Infection

“…The concentration of each cytokine/chemokine was determined from a standard curve derived from either a human or a rhesus recombinant protein and therefore represents an estimate of the cytokine/chemokine concentration in each sample. All of the MAbs used in this assay are cross-reactive with RM cytokines/chemokines, as reported earlier (5,(30)(31)(32)(33)(34). The multiplex plate was read with a Bio-Plex 200 suspension array Luminex system (Bio-Rad) as reported previously (5,35).…”