Paige E. Anton

Despite growing evidence that neuroimmune dysfunction contributes to Alcohol Use Disorder (AUD) pathology, the underlying neuroinflammatory mechanisms that may promote alcohol consumption are not as clear. We recently report that specific knockdown of interferon regulatory factor 7 (IRF7) in the anterior insula (aIC) mitigates escalation in ethanol self-administration in rats. In addition, we find pro-inflammatory activation of microglia contributes to other AUD-related behavioral impairments. Here, we sought to determine if pro-inflammatory activation of microglia from ethanol contributes to elevations in IRF7 and ethanol self-administration in rats. Male Wistar rats were trained under our ethanol self-administration paradigm (15% v/v; FR2 vs inactive lever) followed by 1-4 cycles of chronic intermittent ethanol vapor exposure (CIE). To inhibit microglia, rats were treated with minocycline (30mg/kg, i.p.) before and after each ethanol vapor session. Escalation in self-administration and biochemical markers were assessed 72 hours into abstinence. We found CIE increased ethanol self-administration, which was positively correlated with aIC IRF7 levels. Minocycline treatment blunted IRF7 expression and alleviated ethanol self-administration following CIE. LC-MS/MS proteomics of primary microglia from the aIC of rats following CIE with and without minocycline treatment indicate minocycline promotes metabolic and ribosomal re-wiring of microglia during early abstinence. These data suggest a role for microglia in driving both IRF7 levels and escalation in ethanol self-administration in early abstinence.

Binge alcohol use is increasing among aged adults (>65 yr). Alcohol-related toxicity in aged adults is associated with neurodegeneration; yet, the molecular underpinnings of this age-related sensitivity to alcohol are not well described. Studies utilizing rodent models of neurodegenerative disease reveal heightened activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and Nod-like receptor 3 (NLRP3) mediate microglia activation and associated neuronal injury. Our group, and others, have implicated hippocampal-resident microglia as key producers of inflammatory mediators; yet, the link between inflammation and neurodegeneration has not been established in models of binge ethanol exposure and advanced age. Here, we report binge ethanol increased the proportion of NLRP3+ microglia in the hippocampus of aged (18 to 20 mo) female C57BL/6N mice compared with young (3 to 4 mo). In primary microglia, ethanol-induced expression of reactivity markers and NLRP3 inflammasome activation were more pronounced in microglia from aged mice compared with young. Using a NLRP3-specific inhibitor (OLT1177) and a novel brain-penetrant Nanoligomer that inhibits NF-κB and NLRP3 translation (SB_NI_112), we find ethanol-induced microglial reactivity can be attenuated by OLT1177 and SB_NI_112 in microglia from aged mice. In a model of intermittent binge ethanol exposure, SB_NI_112 prevented ethanol-mediated microglia reactivity, IL-1β production, and tau hyperphosphorylation in the hippocampus of aged mice. These data suggest early indicators of neurodegeneration occurring with advanced age and binge ethanol exposure are driven by NF-κB and NLRP3. Further investigation is warranted to explore the use of targeted immunosuppression via Nanoligomers to attenuate neuroinflammation after alcohol consumption in the aging populations.

Binge alcohol use is increasing among aged adults (>65 years). Alcohol-related toxicity in aged adults is associated with neurodegeneration, yet the molecular underpinnings of age-related sensitivity to alcohol are not well described. Studies utilizing rodent models of neurodegenerative disease reveal heightened activation of Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and Nod like receptor 3 (NLRP3) mediate microglia activation and associated neuronal injury. Our group, and others, have implicated hippocampal-resident microglia as key producers of inflammatory mediators, yet the link between inflammation and neurodegeneration has not been established in models of binge ethanol exposure and advanced age. Here, we report binge ethanol increased the proportion of NLRP3 ⁺ microglia in the hippocampus of aged (18-20 months) female C57BL/6N mice compared to young (3-4 months). In primary microglia, ethanol-induced expression of reactivity markers and NLRP3 inflammasome activation were more pronounced in microglia from aged mice compared to young. Making use of an NLRP3-specific inhibitor (OLT1177) and a novel brain- penetrant Nanoligomer that inhibits NF-κB and NLRP3 translation (SB_NI_112), we find ethanol- induced microglial reactivity can be attenuated by OLT1177 and SB_NI_112 in microglia from aged mice. In a model of intermittent binge ethanol exposure, SB_NI_112 prevented ethanol-mediated microglia reactivity, IL-1β production, and tau hyperphosphorylation in the hippocampus of aged mice. These data suggest early indicators of neurodegeneration occurring with advanced age and binge ethanol exposure are NF-κB- and NLRP3-dependent. Further investigation is warranted to explore the use of targeted immunosuppression via Nanoligomers to attenuate neuroinflammation after alcohol consumption in the aged.