Alcohol misuse has long-term effects on immune function, and can alter the inflammatory profile basally and following an insult. Additionally, alcohol-induced inflammation may promote alcohol cravings and dependence, suggesting a bidirectional relationship. However, most studies assessing the relationship between alcohol consumption and innate immune signaling were performed exclusively in males or yielded ambiguous results. The present study extended this work by assessing the bidirectional association between ethanol (EtOH) and inflammation in the Drinking in the Dark (DID) binge paradigm in adult females. A week after receiving LPS (1 mg/kg) or saline, female C57BL/6 J mice were evaluated for voluntary EtOH consumption in a prolonged DID paradigm. Next, whether prolonged voluntary EtOH intake influenced the inflammatory response to LPS in the brain and liver was assessed. Our results demonstrate that voluntary binge drinking in the DID model was unaltered by a prior immune challenge. However, prolonged EtOH consumption attenuated the central and peripheral immune response to LPS exposure. Compared to water-drinking females, EtOH-consuming females showed diminished brain levels of interleukin-1β (IL-1β) (p = 0.005), liver levels of IL-1β, and tumor necrosis factor-α four hours after LPS (p < 0.05). Twelve days of DID was not sufficient to promote a basal increase in inflammatory cytokines. Collectively, the results demonstrate that prolonged voluntary EtOH exposure blunts the proinflammatory innate immune response to a secondary immune challenge in adult females. These findings provide insight into the immunomodulatory effects of binge EtOH intake in females, extending our understanding of the role of inflammatory signaling in alcohol-consuming individuals.

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.

Excessive alcohol consumption significantly impacts human health, particularly the brain, due to its susceptibility to oxidative stress, which contributes to neurodegenerative conditions. Alcohol metabolism in the brain occurs primarily via catalase, followed by CYP2E1 pathways. Excess alcohol metabolized by CYP2E1 generates reactive oxygen/nitrogen species (ROS/RNS), leading to cell injury via altering many different pathways. Elevated oxidative stress impairs autophagic processes, increasing post-translational modifications and further exacerbating mitochondrial dysfunction and ER stress, leading to cell death. The literature highlights that alcohol-induced oxidative stress disrupts autophagy and mitophagy, contributing to neuronal damage. Key mechanisms include mitochondrial dysfunction, ER stress, epigenetics, and the accumulation of oxidatively modified proteins, which lead to neuroinflammation and impaired cellular quality control. These processes are exacerbated by chronic alcohol exposure, resulting in the suppression of protective pathways like NRF2-mediated antioxidant responses and increased susceptibility to neurodegenerative changes in the brain. Alcohol-mediated neurotoxicity involves complex interactions between alcohol metabolism, oxidative stress, and autophagy regulation, which are influenced by various factors such as drinking patterns, nutritional status, and genetic/environmental factors, highlighting the need for further molecular studies to unravel these mechanisms and develop targeted interventions.

Human studies suggest that heavy alcohol use may be an etiological factor contributing to the development of Alzheimer's disease (AD) neuropathology. Both alcohol use disorder (AUD) and AD share common underlying neuropathology, including proinflammatory high-mobility group box 1 (HMGB1)-mediated neuroimmune signaling and basal forebrain cholinergic neuron degeneration. Adolescent onset of binge drinking represents a significant risk factor for later development of an AUD, and accumulating evidence suggests that adolescent initiation of heavy alcohol use induces HMGB1 signaling and causes degeneration of the basal forebrain cholinergic system that persists into adulthood. However, it is unknown whether adolescent binge drinking confers increased risk for later development of AD-associated neuropathology through persistent induction of proinflammatory HMGB1 neuroimmune signaling. To investigate this question, we first (Experiment 1) assessed AD-associated neuropathology in the post-mortem human basal forebrain of individuals with AUD and an adolescent age of drinking onset relative to age-matched moderate drinking controls (CONs). In Experiment 2, we treated non-transgenic and 5xFAD male and female mice, which overexpress both mutant human APP and PS1, with adolescent intermittent ethanol (AIE; 5.0 g/kg, i.g. 2-days on/2-days off; postnatal day [P]30 - P55), and assessed AD-associated neuropathology in the adult (P100) basal forebrain. In Experiment 3, 5xFAD female mice received AIE treatment followed by glycyrrhizic acid (150 mg/L), an HMGB1 inhibitor, in drinking water from P56 to P100, and basal forebrain tissue was collected on P100 for assessment of AD-associated neuropathology. In the post-mortem human AUD basal forebrain (Experiment 1), we report upregulation of Hmgb1 and the HMGB1 receptors Rage and Tlr4 as well as microglial activation and increased intraneuronal Aβ1-42 accumulation in association with reduced cholinergic neuron marker expression (ChAT). In the 5xFAD mouse model (Experiment 2), AIE accelerated AD-associated induction of Hmgb1 proinflammatory neuroimmune genes, microglial activation, and reductions of ChAT+ basal forebrain cholinergic neurons in the adult female, but not male, basal forebrain. In Experiment 3, post-AIE treatment with glycyrrhizic acid rescued the AIE-induced acceleration of AD-associated increases in proinflammatory HMGB1 neuroimmune signaling, microglial activation, and persistent reductions of basal forebrain cholinergic neurons in adult 5xFAD female mice. Together, these findings suggest that adolescent binge ethanol exposure may represent an underappreciated etiological factor contributing to onset of AD-associated neuropathology in adulthood through HMGB1- mediated neuroimmune signaling.

Between the neurotransmission systems modulated by alcohol, the opioid system has been receiving attention in studies that seek to understand its relationship to the effects of addictive substances and different neuropsychiatric disorders. The use of naltrexone stands out in determining the mechanisms of the opioid system, as it acts as an opioid antagonist and consequently generates neurochemical responses. This study aimed to evaluate the pharmacological modulation of opioids on behavioral and neurobiological aspects in adult zebrafish submitted to the protocol of repeated exposure to ethanol and treated with naltrexone. Opioid modulation using naltrexone has been shown to modulate anxiety-like behavior, presenting anxiolytic properties in isolation, in addition to reversing the anxiogenic effect of ethanol through the Novel tank and Light/dark test. Naltrexone increased serotonin and dopamine levels, while ethanol antagonized these effects. In contrast, the interaction between ethanol and naltrexone raised noradrenaline levels. Naltrexone altered glutamate levels, however, ethanol reversed it. Ethanol acted on glutamate transporters increasing their activities, while naltrexone treatment reduced activities. No significant results were found in the pro-oxidant parameters, however, ethanol reduced SOD activity while naltrexone reversed. The same occurred in CAT activity. Also, naltrexone up-regulated the expression of genes related to the dopaminergic, glutamatergic, and opioid systems. The genes used as markers of the inflammatory process and glial activity were modulated by ethanol and together with naltrexone, respectively. Taken together, our findings reinforce the importance of opioid signaling on biochemical and molecular bases related to neuropsychiatric behaviors and diseases, such as anxiety and substance dependence.

Adolescence is a conserved neurodevelopmental period encompassing maturation of glia and the innate immune system that parallels refinement of brain structures, neurotransmitter systems, and neurocircuitry. Given the vast neurodevelopmental processes occurring during adolescence, spanning brain structural and neurocircuitry refinement to maturation of neurotransmitter systems, glia, and the innate immune system, insults incurred during this critical period of neurodevelopment, could have profound effects on brain function and behavior that persist into adulthood. Adolescent binge drinking is common and associated with many adverse outcomes that may underlie the lifelong increased risk of alcohol-related problems and development of an alcohol use disorder (AUD). In this chapter, we examined the impact of adolescent binge drinking models using the adolescent intermittent ethanol (AIE) model on adult neurobiology. These studies implicate proinflammatory neuroimmune signaling across glia and neurons in persistent AIE-induced neuropathology. Some of these changes are reversible, providing unique opportunities for the development of treatments to prevent many of the long-term consequences of adolescent alcohol misuse.

Alcohol is the most abused substance among adolescents and has a profound impact on health, society, and the economy. Alcohol intoxication is linked to neuroinflammation and neuronal damage, which result in behavioral alterations such as motor dysfunction, neuronal injury, cognitive deficits, and inflammation. Alcohol-induced neuroinflammation is associated with the activation of central nervous system cells, including astrocytes, and the release of proinflammatory cytokines. In this study, we investigated the role of the NLRP6 inflammasome signaling pathway in inducing cellular activation and neuroinflammation in human primary astrocytes exposed to ethanol. Our results demonstrated that ethanol upregulates the expression of NLRP6 inflammasome signaling mediators, including NLRP6, caspase 1, and proinflammatory cytokines IL-1β and IL-18, in human primary astrocytes. Gene silencing studies using NLRP6 siRNA further validate ethanol-mediated activation of NLRP6, cleavage of caspase 1, IL-1β, and IL-18 in human primary astrocytes. miR array analysis of ethanol-exposed human primary astrocytes reveals decreased levels of miR-339, accompanied by an upregulation of NLRP6 inflammasome signaling and astrocyte activation. Through bioinformatics analyses, Argonaute immunoprecipitation assays, and miR-339 overexpression experiments, we identify NLRP6 as a novel 3'-UTR target of miR-339. Overall, our findings confirmed the involvement of miR-339 in NLRP6 inflammasome signaling and its association with cellular activation and neuroinflammation in human primary astrocytes exposed to ethanol and provide novel insights highlighting a previously unrecognized mechanism in alcohol-induced neuroinflammation.

Among the many changes associated with aging, inflammation in the central nervous system (CNS) and throughout the body likely contributes to the constellation of health-related maladies associated with aging. Genetics, lifestyle factors, and environmental experiences shape the trajectory of aging-associated inflammation, including the developmental timing, frequency, and intensity of alcohol consumption. This chapter posits that neuroinflammatory processes form a critical link between alcohol exposure and the trajectory of healthy aging, at least in part through direct or indirect interactions with cholinergic circuits that are crucial to cognitive integrity. In this chapter, we begin with a discussion of how inflammation changes from early development through late aging; discuss the role of inflammation and alcohol in the emergence of mild cognitive impairment (MCI); elaborate on critical findings on the contribution of alcohol-related thiamine deficiency to the loss of cholinergic function and subsequent development of Wernicke-Korsakoff syndrome (WKS); and present emerging findings at the intersection of alcohol and Alzheimer's disease and related dementias (ADRD). In doing so, our analysis points toward inflammation-mediated compromise of basal forebrain cholinergic function as a key culprit in cognitive dysfunction associated with chronic alcohol exposure, effects that may be rescuable through either pharmacological or behavioral approaches. Furthermore, our chapter reveals an interesting dichotomy in the effects of alcohol on neuropathological markers of ADRD that depend upon both biological sex and genetic vulnerability.

Alcohol use disorder (AUD) is a public health problem characterized by a marked increment in systemic inflammation. In the last few years, it has been described as the role of alcohol in neuroinflammation affecting some aspects of neuronal function. Interestingly, inflammation is reduced with fenofibrate treatment, a PPARα agonist used to treat dyslipidemia. On the other hand, alcohol has been associated with chronic inflammation and fibrosis in the lungs, affecting their normal function and increasing respiratory infections. However, a deep characterization of the role of alcohol in the worsening of chronic respiratory diseases has not been described completely. In this work, we present a novel study using rats treated with alcohol and fenofibrate to evaluate the relevant features of chronic respiratory disease: inflammation, mucus hypersecretion, and fibrosis. The analysis of extracted lungs showed an increment in the inflammatory infiltrates and pro-inflammatory cytokine levels associated with alcohol. Interestingly, the treatment with fenofibrate decreased the expression of these markers and the infiltrates observed in the lungs. The levels of mucin Muc5ac showed an increment in animals treated with alcohol. However, this increment was markedly reduced if animals were subsequently treated with fenofibrate. Finally, we documented an increment of collagen deposition around airways in the animals treated with alcohol compared with control animals. However, fenofibrate treatment reduced this deposition to a level similar to the control animals. These results showed the role of alcohol in the increment of pathological features in the lungs. Moreover, these features were attenuated due to the fibrate treatment, which allows us to glimpse this drug's promising role as lung anti-inflammatory therapy.

Clinical and experimental evidence indicates that alcohol use causes various abnormalities in the immune system and compromises immune functions. However, the mechanistic understanding of ethanol's effects on the immune system remains limited. Cyclic AMP (cAMP) regulates multiple processes, including immune responses. Earlier research indicated that type 7 adenylyl cyclase (AC7) regulates the immune system and is highly responsive to ethanol. Therefore, we hypothesized that AC7 is a central player in regulating the effects of alcohol on innate immune responses. To test this hypothesis, we utilized a myeloid lineage-specific AC7 KO mouse model and compared the effects of acute and chronic ethanol treatment on their innate immune responses induced by systemic lipopolysaccharide (LPS) challenge. Our results demonstrate that AC7 KO mice had significantly lower survival rates under LPS challenge. Chronic ethanol consumption rescued AC7 KO mice from LPS-induced death. AC7 KO and ethanol, acute and chronic, affected several measurements of cytokine mRNA expressions, including IL-1β, TNFα, IL-6, and IL-10 in the lung and liver. In a few cases, statistical analysis indicated that these two factors interacted, suggesting that AC7 played some role in ethanol's effect on cytokine expression. Thus, this study demonstrated AC7's role in ethanol's effect on the innate immune response.

Chemokines are immunoregulatory proteins with pleiotropic functions involved in neuromodulation, neurogenesis, and neurotransmission. The way chemokines affect the CNS plays an important role in modulating various conditions that could have negative impact on CNS functions, including development of alcohol use disorders. In this review, we analyzed the literature data available on the problem of chemokine participation in pathogenesis, clinical presentation, and remission of alcohol use disorders both in animal models and in the study of patients with alcoholism. The presented information confirms the hypothesis that the alcohol-induced chemokine production could modulate chronic neuroinflammation. Thus, the data summarized and shown in this review are focused on the relevant direction of research in the field of psychiatry, which is in demand by both scientists and clinical specialists.

- Alcohol-induced pro-inflammatory activation might influence cellular and synaptic pathology, thus contributing to the behavioral phenotypes associated with alcohol use disorders. In the present study, the possible anti-inflammatory properties of N-[(4-trifluoromethyl)-benzyl]4-methoxybutyramide (GET73), a promising therapeutic agent for alcohol use disorder treatment, were evaluated in primary cultures of rat cortical microglia.

- Primary cultures of cerebral cortex microglial cells were treated with 100 ng/ml lipopolysaccharide (LPS; 8 h, 37 °C) or 75 mM ethanol (EtOH; 4 days, 37 °C) alone or in the presence of GET73 (1-30 µM). At the end of the incubation period, multiparametric quantification of cytokines/chemokines was performed by using the xMAP technology and Luminex platform. Furthermore, cultured microglial cell viability following the treatment with EtOH and GET73, alone or in combination, has been measured by a colorimetric assay (i.e. MTT assay).

- GET73 (10 and 30 µM) partially or fully prevented the LPS-induced increase of IL-6, IL-1β, RANTES/CCL5 protein and MCP-1/CCL2 levels. On the contrary, GET73 failed to attenuate the TNF-α level increase induced by LPS. Furthermore, GET73 treatment (10-30 µM) significantly attenuated or prevented the EtOH-induced increase of TNF-α, IL-6, IL-1β and MCP-1/CCL2 levels. Finally, at all the concentrations tested (1-30 µM), the GET73 treatment did not alter the EtOH-induced reduction of microglial cell viability.

- The current results provide the first in vitro evidence of GET73 protective properties against EtOH-induced neuroinflammation. These data add more information on the complex and multifactorial profile of action of the compound, further supporting the significance of developing GET73 as a therapeutic tool for the treatment of individuals with alcohol use disorders.

Binge drinking (i.e., consuming enough alcohol to achieve a blood ethanol concentration of 80 mg/dL, approximately 4-5 drinks within 2 hours), particularly in early adolescence, can promote progressive increases in alcohol drinking and alcohol-related problems that develop into compulsive use in the chronic relapsing disease, alcohol use disorder (AUD). Over the past decade, neuroimmune signaling has been discovered to contribute to alcohol-induced changes in drinking, mood, and neurodegeneration. This review presents a mechanistic hypothesis supporting high mobility group box protein 1 (HMGB1) and Toll-like receptor (TLR) signaling as key elements of alcohol-induced neuroimmune signaling across glia and neurons, which shifts gene transcription and synapses, altering neuronal networks that contribute to the development of AUD. This hypothesis may help guide further research on prevention and treatment.

The authors used the search terms "HMGB1 protein," "alcohol," and "brain" across PubMed, Scopus, and Embase to find articles published between 1991 and 2023.

The database search found 54 references in PubMed, 47 in Scopus, and 105 in Embase. A total of about 100 articles were included.

In the brain, immune signaling molecules play a role in normal development that differs from their functions in inflammation and the immune response, although cellular receptors and signaling are shared. In adults, pro-inflammatory signals have emerged as contributing to brain adaptation in stress, depression, AUD, and neurodegenerative diseases. HMGB1, a cytokine-like signaling protein released from activated cells, including neurons, is hypothesized to activate pro-inflammatory signals through TLRs that contribute to adaptations to binge and chronic heavy drinking. HMGB1 alone and in heteromers with other molecules activates TLRs and other immune receptors that spread signaling across neurons and glia. Both blood and brain levels of HMGB1 increase with ethanol exposure. In rats, an adolescent intermittent ethanol (AIE) binge drinking model persistently increases brain HMGB1 and its receptors; alters microglia, forebrain cholinergic neurons, and neuronal networks; and increases alcohol drinking and anxiety while disrupting cognition. Studies of human postmortem AUD brain have found elevated levels of HMGB1 and TLRs. These signals reduce cholinergic neurons, whereas microglia, the brain's immune cells, are activated by binge drinking. Microglia regulate synapses through complement proteins that can change networks affected by AIE that increase drinking, contributing to risks for AUD. Anti-inflammatory drugs, exercise, cholinesterase inhibitors, and histone deacetylase epigenetic inhibitors prevent and reverse the AIE-induced pathology. Further, HMGB1 antagonists and other anti-inflammatory treatments may provide new therapies for alcohol misuse and AUD. Collectively, these findings suggest that restoring the innate immune signaling balance is central to recovering from alcohol-related pathology.

Alcohol is the most widely abused substance in the world, the leading source of mortality in 15-49-year-olds, and a major risk factor for heart disease, liver disease, diabetes, and cancer. Despite this, alcohol is regularly misused in wider society. Consumers of excess alcohol often note a constellation of negative symptoms, known as the alcohol hangover. However, the alcohol hangover is not considered to have long-term clinical significance by clinicians or consumers. We undertook a critical review of the literature to demonstrate the pathophysiological mechanisms of the alcohol hangover. Hereafter, the alcohol hangover is re-defined as a manifestation of sickness behavior secondary to alcohol-induced inflammation, using the Bradford-Hill criteria to demonstrate causation above correlation. Alcohol causes inflammation through oxidative stress and endotoxemia. Alcohol metabolism is oxidative and increased intake causes relative tissue hypoxia and increased free radical generation. Tissue damage ensues through lipid peroxidation and the formation of DNA/protein adducts. Byproducts of alcohol metabolism such as acetaldehyde and congeners, sleep deprivation, and the activation of nonspecific inducible CYP2E1 in alcohol-exposed tissues exacerbate free radical generation. Tissue damage and cell death lead to inflammation, but in the intestine loss of epithelial cells leads to intestinal permeability, allowing the translocation of pathogenic bacteria to the systemic circulation (endotoxemia). This leads to a well-characterized cascade of systemic inflammation, additionally activating toll-like receptor 4 to induce sickness behavior. Considering the evidence, it is suggested that hangover frequency and severity may be predictors of the development of later alcohol-related diseases, meriting formal confirmation in prospective studies. In light of the mechanisms of alcohol-mediated inflammation, research into gut permeability and the gut microbiome may be an exciting future therapeutic avenue to prevent alcohol hangover and other alcohol-related diseases.

Although it is known that APOE genotype is the strongest genetic risk factor for late-onset Alzheimer's disease, development is a multifactorial process. Alcohol use is a contributor to the epidemic of Alzheimer's disease and related dementias in the US and globally, yet mechanisms are not fully understood. Carriers of the APOE ε4 allele show elevated risk of dementia in relation to several lifestyle factors, including alcohol use. In this review, we describe how alcohol interacts with APOE genotype and aging with potential implications for Alzheimer's disease promotion. Age-related immune senescence and "inflammaging" (i.e., low-grade inflammation associated with aging) are increasingly recognized as contributors to age-related disease. We focus on three immune pathways that are likely contributors to Alzheimer's disease development, centering on alcohol and APOE genotype interactions, specifically: 1) microbial translocation and immune activation, 2) the senescence associated secretory phenotype, and 3) neuroinflammation. First, microbial translocation, the unphysiological movement of gut products into systemic circulation, elicits a proinflammatory response and increases with aging, with proposed links to Alzheimer's disease. Second, the senescence associated secretory phenotype is a set of intercellular signaling factors, e.g., proinflammatory cytokines and chemokines, growth regulators, and proteases, that drives cellular aging when senescent cells remain metabolically active. The senescence associated secretory phenotype can drive development of aging-diseases such as Alzheimer's disease. Third, neuroinflammation occurs via numerous mechanisms such as microglial activation and is gaining recognition as an etiological factor in the development of Alzheimer's disease. This review focuses on interactions of alcohol with APOE genotype and aging along these three pathways that may promote Alzheimer's disease. Further research on these processes may inform development of strategies to prevent onset and progression of Alzheimer's disease and to delay associated cognitive decline.

Alcohol, or ethanol, is a major contributor to detrimental diseases and comorbidities worldwide. Alcohol use during pregnancy intervenes the developing embryos leading to morphological changes, neurocognitive defects, and behavioral changes known as fetal alcohol spectrum disorder (FASD). Zebrafish have been used as a model to study FASD; however, the mechanism and the impact of ethanol on oxidative stress and inflammation in the zebrafish FASD model remain unexplored. Hence, we exposed zebrafish embryos to different concentrations of ethanol (0 %, 0.5 %, 1.0 %, 1.25 %, and 1.5 % ethanol (v/v)) at 4-96 hours post-fertilization (hpf) to study and characterize the ethanol concentration for the FASD model to induce oxidative stress and inflammation. Here, we studied the survival rate and developmental toxicity parameters at different time points and measured oxidative stress, reactive oxygen species (ROS) generation, apoptosis, and pro-inflammatory gene expression in zebrafish larvae. Our findings indicate that ethanol causes various developmental abnormalities, including decreased survival rate, spontaneous tail coiling, hatching rate, heart rate, and body length, associated with increased malformation. Further, ethanol exposure induced oxidative stress by increasing lipid peroxidation and nitric oxide production and decreasing glutathione levels. Subsequently, ethanol increased ROS generation, apoptosis, and pro-inflammatory gene (TNF-α and IL-1β) expression in ethanol exposed larvae. 1.25 % and 1.5 % ethanol had significant impacts on zebrafish larvae in all studied parameters. However, 1.5 % ethanol showed decreased survival rate and increased malformations. Overall, 1.25 % ethanol is the ideal concentration to study the oxidative stress and inflammation in the zebrafish FASD model.

Many lines of research have suggested that the neuroactive pregnane steroids, including pregnenolone, progesterone, and allopregnanolone ([3α,5α]-3-hydroxypregnan-20-one, 3α,5α-THP), have therapeutic potential for treatment of alcohol use disorders (AUDs). In this chapter, we systematically address the preclinical and clinical evidence that supports this approach for AUD treatment, describe the underlying neurobiology of AUDs that are targeted by these treatments, and delineate how pregnane steroids may address various components of the disease. This review updates the theoretical framework for understanding how endogenous steroids that modulate the effects of alcohol, stress, excitatory/inhibitory and dopamine transmission, and the innate immune system appear to play a key role in the prevention and mitigation of AUDs. We further discuss newly discovered limitations of pregnane steroid therapies as well as the challenges that are inherent to development of endogenous compounds for therapeutics. We argue that overcoming these challenges presents the opportunity to help millions who suffer from AUDs across the world.

Alcohol use disorder (AUD) courses with inflammation and cognitive decline. Apolipoproteins have emerged as novel target compounds related to inflammatory processes and cognition.

A cross-sectional study was performed on abstinent AUD patients with at least 1 month of abstinence (n  = 33; 72.7% men) and healthy controls (n  = 34; 47.1% men). A battery of plasma apolipoproteins (APOAI, APOAII, APOB, APOCII, APOE, APOJ, and APOM), plasma inflammatory markers (LPS, LBP), and their influence on cognition and presence of the disorder were investigated.

Higher levels of plasma APOAI, APOB, APOE, and APOJ, as well as the proinflammatory LPS, were observed in the AUD group, irrespective of sex, whereas APOM levels were lower vs controls. Hierarchical logistic regression analyses, adjusting for covariates (age, sex, education), associated APOM with the absence of cognitive impairment in AUD and identified APOAI and APOM as strong predictors of the presence or absence of the disorder, respectively. APOAI and APOM did not correlate with alcohol abuse variables or liver status markers, but they showed an opposite profile in their associations with LPS (positive for APOAI; negative for APOM) and cognition (negative for APOAI; positive for APOM) in the entire sample.

The HDL constituents APOAI and APOM were differentially regulated in the plasma of AUD patients compared with controls, playing divergent roles in the disorder identification and associations with inflammation and cognitive decline.

Alcohol consumption is known to have detrimental effects on memory function, with various studies implicating ethanol in the impairment of cognitive processes related to memory retention and retrieval. This review aims to elucidate the complex neurobiological mechanisms underlying ethanol-induced memory impairment. Through a thorough search of existing literature using electronic databases, relevant articles focusing on the neurobiological mechanisms of ethanol on memory were identified and critically evaluated. This review focuses on the molecular and neural pathways through which ethanol exerts its effects on memory formation, consolidation, and recall processes. Key findings from the included studies shed light on the impact of ethanol on neurotransmitter systems, synaptic plasticity, and neuroinflammation in relation to memory impairment. This review contributes to a better understanding of the intricate mechanisms by which alcohol impairs memory function, offering insights for future research directions and the development of targeted interventions to alleviate these cognitive impairments.

Chronic ethanol consumption is a prevalent condition in contemporary society and exacerbates anxiety symptoms in healthy individuals. The activation of microglia, leading to neuroinflammatory responses, may serve as a significant precipitating factor; however, the precise molecular mechanisms underlying this phenomenon remain elusive. In this study, we initially confirmed that chronic ethanol exposure (CEE) induces anxiety-like behaviors in mice through open field test and elevated plus maze test. The cGAS/STING signaling pathway has been confirmed to exhibits a significant association with inflammatory signaling responses in both peripheral and central systems. Western blot analysis confirmed alterations in the cGAS/STING signaling pathway during CEE, including the upregulation of p-TBK1 and p-IRF3 proteins. Moreover, we observed microglial activation in the prefrontal cortex (PFC) of CEE mice, characterized by significant alterations in branching morphology and an increase in cell body size. Additionally, we observed that administration of CEE resulted in mitochondrial dysfunction within the PFC of mice, accompanied by a significant elevation in cytosolic mitochondrial DNA (mtDNA) levels. Furthermore, our findings revealed that the inhibition of STING by H-151 effectively alleviated anxiety-like behavior and suppressed microglial activation induced by CEE. Our study unveiled a significant association between anxiety-like behavior, microglial activation, inflammation, and mitochondria dysfunction during CEE.

Histamine, a bioactive component in certain foods such as Huangjiu has been associated with liver injury and disrupted intestinal balance. This study explored the potential therapeutic effects of fucoidan (FCD) in mitigating histamine-induced imbalances in mice. We found that FCD mitigated liver injury, reducing transaminases, oxidative stress, and inflammation. Histological improvements included decreased cell infiltration and necrosis. FCD restored tight junction proteins and suppressed inflammation-related genes. Western blot analysis revealed FCD's impact on TGF-β1, p-AKT, AKT, CYP2E1, Grp78, NLRP3, Cas-1, and GSDMD. Gut LPS levels decreased with FCD. Gut microbiota analysis showed FCD's modulation effect, reducing Firmicutes and increasing Bacteroides. FCD demonstrates potential in alleviating histamine-induced liver injury, regulating inflammation, and influencing gut microbiota. Further research exploring higher dosages and additional parameters is warranted.

We aimed to investigate the effectiveness of physical training as a protective strategy to mitigate alveolar bone damage and blood antioxidant defense caused by ethanol (EtOH) consumption in a binge-drinking pattern. Male Wistar rats aged approximately 90 days were divided into four groups: control, training, EtOH, and training + EtOH. The physical training protocol was conducted on a treadmill for four consecutive weeks, while the animals in the EtOH group were administered EtOH via orogastric gavage for three consecutive days each week, following the binge drink pattern. After the training period, blood and mandibles were collected for plasma oxidative biochemistry analysis, and the alveolar bone was subjected to physicochemical composition analysis, tissue evaluation, and microtomography evaluation. Our results showed that EtOH induced oxidative stress and physical exercise promoted the recovery of antioxidant action. Physical training minimized the damage to the mineral/matrix composition of the alveolar bone due to EtOH consumption and increased the density of osteocytes in the trained group treated with EtOH than in those exposed only to EtOH. Furthermore, physical training reduced damage to the alveolar bone caused by EtOH consumption. Our findings suggest that physical training can serve as an effective strategy to reduce systemic enzymatic oxidative response damage and alleviate alveolar bone damage resulting from alcohol consumption. Further investigations are warranted to elucidate the underlying mechanisms and explore, in addition to physical training, the potential effects of other activities with varying intensities on managing alcohol-induced bone damage.

The impact of Alzheimer's disease (AD) and its related dementias is rapidly expanding, and its mitigation remains an urgent social and technical challenge. To date there are no effective treatments or interventions for AD, but recent studies suggest that alcohol consumption is correlated with the risk of developing dementia. In this review, we synthesize data from preclinical, clinical, and epidemiological models to evaluate the combined role of alcohol consumption and serotonergic dysfunction in AD, underscoring the need for further research on this topic. We first discuss the limitations inherent to current data-collection methods, and how neuropsychiatric symptoms common among AD, alcohol use disorder, and serotonergic dysfunction may mask their co-occurrence. We additionally describe how excess alcohol consumption may accelerate the development of AD via direct effects on serotonergic function, and we explore the roles of neuroinflammation and proteostasis in mediating the relationship between serotonin, alcohol consumption, and AD. Lastly, we argue for a shift in current research to disentangle the pathogenic effects of alcohol on early-affected brainstem structures in AD.

Pregnane neuroactive steroids, notably allopregnanolone and pregnenolone, exhibit efficacy in mitigating inflammatory signals triggered by toll-like receptor (TLR) activation, thus attenuating the production of inflammatory factors. Clinical studies highlight their therapeutic potential, particularly in conditions like postpartum depression (PPD), where the FDA-approved compound brexanolone, an intravenous formulation of allopregnanolone, effectively suppresses TLR-mediated inflammatory pathways, predicting symptom improvement. Additionally, pregnane neurosteroids exhibit trophic and anti-inflammatory properties, stimulating the production of vital trophic proteins and anti-inflammatory factors. Androstane neuroactive steroids, including estrogens and androgens, along with dehydroepiandrosterone (DHEA), display diverse effects on TLR expression and activation. Notably, androstenediol (ADIOL), an androstane neurosteroid, emerges as a potent anti-inflammatory agent, promising for therapeutic interventions. The dysregulation of immune responses via TLR signaling alongside reduced levels of endogenous neurosteroids significantly contributes to symptom severity across various neuropsychiatric disorders. Neuroactive steroids, such as allopregnanolone, demonstrate efficacy in alleviating symptoms of various neuropsychiatric disorders and modulating neuroimmune responses, offering potential intervention avenues. This review emphasizes the significant therapeutic potential of neuroactive steroids in modulating TLR signaling pathways, particularly in addressing inflammatory processes associated with neuropsychiatric disorders. It advances our understanding of the complex interplay between neuroactive steroids and immune responses, paving the way for personalized treatment strategies tailored to individual needs and providing insights for future research aimed at unraveling the intricacies of neuropsychiatric disorders.

The adverse use of alcohol is a serious global public health problem. Maternal alcohol consumption during pregnancy usually causes prenatal alcohol exposure (PAE) in the developing fetus, leading to a spectrum of disorders known as fetal alcohol spectrum disorders (FASD) and even fetal alcohol syndrome (FAS) throughout the lifelong sufferers. The prevalence of FASD is approximately 7.7 per 1,000 worldwide, and is even higher in developed regions. Generally, Ethanol in alcoholic beverages can impair embryonic neurological development through multiple pathways leading to FASD. Among them, the leading mechanism of FASDs is attributed to ethanol-induced neuroinflammatory damage to the central nervous system (CNS). Although the underlying molecular mechanisms remain unclear, the remaining multiple pathological mechanisms is likely due to the neurotoxic damage of ethanol and the resultant neuronal loss. Regardless of the molecular pathway, the ultimate outcome of the developing CNS exposed to ethanol is almost always the destruction and apoptosis of neurons, which leads to the reduction of neurons and further the development of FASD. In this review, we systematically summarize the current research progress on the pathogenesis of FASD, which hopefully provides new insights into differential early diagnosis, treatment and prevention for patents with FASD.

Acute cognitive impairments termed delirium often occur after inflammatory insults in elderly patients. While previous preclinical studies suggest mitochondria as a target for reducing neuroinflammation and cognitive impairments after LPS injection, fewer studies have evaluated the effects of a low-grade systemic inflammation in the aged brain. Thus, to identify the significance of mitochondrial dysfunction after a clinically relevant systemic inflammatory stimulus, we injected old-aged mice (18-20 months) with low-dose lipopolysaccharide (LPS, 0.04 mg/kg). LPS injection reduced mitochondrial respiration in the hippocampus 24 h after injection (respiratory control ratio [RCR], state3u/state4o; control = 2.82 ± 0.19, LPS = 2.57 ± 0.08). However, gene expression of the pro-inflammatory cytokine IL-1β was increased (RT-PCR, control = 1.00 ± 0.30; LPS = 2.01 ± 0.67) at a more delayed time point, 48 h after LPS injection. Such changes were associated with cognitive impairments in the Barnes maze and fear chamber tests. Notably, young mice were unaffected by low-dose LPS, suggesting that mitochondrial dysfunction precedes neuroinflammation and cognitive decline in elderly patients following a low-grade systemic insult. Our findings highlight mitochondria as a potential therapeutic target for reducing delirium in elderly patients.

Chronic ethanol exposure often triggers neuroinflammation in the brain's reward system, potentially promoting the drive for ethanol consumption. A main marker of neuroinflammation is the microglia-derived monocyte chemoattractant protein 1 (MCP1) in animal models of alcohol use disorder in which ethanol is forcefully given. However, there are conflicting findings on whether MCP1 is elevated when ethanol is taken voluntarily, which challenges its key role in promoting motivation for ethanol consumption. Here, we studied MCP1 mRNA levels in areas implicated in consumption motivation-specifically, the prefrontal cortex, hippocampus, and striatum-as well as in the cerebellum, a brain area highly sensitive to ethanol, of C57BL/6 mice subjected to intermittent and voluntary ethanol consumption for two months. We found a significant increase in MCP1 mRNA levels in the cerebellum of mice that consumed ethanol compared to controls, whereas no significant changes were observed in the prefrontal cortex, hippocampus, or striatum or in microglia isolated from the hippocampus and striatum. To further characterize cerebellar neuroinflammation, we measured the expression changes in other proinflammatory markers and chemokines, revealing a significant increase in the proinflammatory microRNA miR-155. Notably, other classical proinflammatory markers, such as TNFα, IL6, and IL-1β, remained unaltered, suggesting mild neuroinflammation. These results suggest that the onset of neuroinflammation in motivation-related areas is not required for high voluntary consumption in C57BL/6 mice. In addition, cerebellar susceptibility to neuroinflammation may be a trigger to the cerebellar degeneration that occurs after chronic ethanol consumption in humans.

Aquaporins like AQP1, AQP3, and AQP4 are known to be involved in the pathophysiology of inflammation based on earlier reports. This study aimed to evaluate the involvement of Aquaporins as a potential target of inflammation. The study also investigates the efficacy of methanolic extract of Garcinia (GME) and its potent phytocompound (garcinol) against the Aquaporins involved in inflammation. siRNA silencing of AQP3 was carried out in RAW264.7 cells followed by LPS stimulation (1 µg/ml) and assessment of important markers of inflammation including NO, PGE2, TNF-α, IL-6, IL-1β, CCL20, iNOS and COX-2. To assess the anti-inflammatory potential of Garcinia extract and garcinol, cells were stimulated with 1 µg/ml LPS in the absence and presence of increasing concentrations of GME and garcinol. During the experimental period, extract concentrations (115 µg/ml and 230 µg/ml for RAW264.7; 118 µg/ml and 236 µg/ml for THP-1) and garcinol concentrations (6 µM and 12 µM for RAW264.7; 3 µM and 6 µM for THP-1) were selected based on the IC50. The anti-inflammatory effects were assessed by measuring the levels of TNF-α, IL-1β, IL-6, and CCL20 in LPS-stimulated cells. The AQP expression was studied at transcriptional and translational levels using qPCR and Western blot analysis respectively. AQP3 knockdown significantly decreased the NO, PGE2, TNF-α, IL-1β levels along with iNOS and COX-2 mRNA expression. LPS stimulation led to a significant increase in the mRNA and protein level expression AQP1, AQP3, and AQP4 in RAW264.7 cells; and AQP1 and AQP3 in THP-1 cells indicating their role as markers of inflammation. GME and garcinol effectively suppressed the LPS-induced proinflammatory cytokine production in both cell lines. The results indicate that AQP1, AQP3, and AQP4 could play a crucial role as markers of inflammation. Anti-inflammatory agents like Garcinia could potentially decrease the expression of such AQPs, thus inhibiting the inflammatory process.

Adolescent alcohol drinking is linked to high rates of adult alcohol problems and alcohol use disorder (AUD). The Neurobiology of Alcohol Drinking in Adulthood (NADIA) consortium adolescent intermittent ethanol (AIE) models adolescent binge drinking, followed by abstinent maturation to adulthood to determine the persistent AIE changes in neurobiology and behavior. AIE increases adult alcohol drinking and preference, increases anxiety and reward seeking, and disrupts sleep and cognition, all risks for AUD. In addition, AIE induces changes in neuroimmune gene expression in neurons and glia that alter neurocircuitry and behavior. HMGB1 is a unique neuroimmune signal released from neurons and glia by ethanol that activates multiple proinflammatory receptors, including Toll-like receptors (TLRs), that spread proinflammatory gene induction. HMGB1 expression is increased by AIE in rat brain and in post-mortem human AUD brain, where it correlates with lifetime alcohol consumption. HMGB1 activation of TLR increase TLR expression. Human AUD brain and rat brain following AIE show increases in multiple TLRs. Brain regional differences in neurotransmitters and cell types impact ethanol responses and neuroimmune gene induction. Microglia are monocyte-like cells that provide trophic and synaptic functions, that ethanol proinflammatory signals sensitize or "prime" during repeated drinking cycles, impacting neurocircuitry. Neurocircuits are differently impacted dependent upon neuronal-glial signaling. Acetylcholine is an anti-inflammatory neurotransmitter. AIE increases HMGB1-TLR4 signaling in forebrain, reducing cholinergic neurons by silencing multiple cholinergic defining genes through upregulation of RE-1 silencing factor (REST), a transcription inhibitor known to regulate neuronal differentiation. HMGB1 REST induction reduces cholinergic neurons in basal forebrain and cholinergic innervation of hippocampus. Adult brain hippocampal neurogenesis is regulated by a neurogenic niche formed from multiple cells. In vivo AIE and in vitro studies find ethanol increases HMGB1-TLR4 signaling and other proinflammatory signaling as well as reducing trophic factors, NGF, and BDNF, coincident with loss of the cholinergic synapse marker vChAT. These changes in gene expression-transcriptomes result in reduced adult neurogenesis. Excitingly, HMGB1 antagonists, anti-inflammatories, and epigenetic modifiers like histone deacetylase inhibitors restore trophic the neurogenesis. These findings suggest anti-inflammatory and epigenetic drugs should be considered for AUD therapy and may provide long-lasting reversal of psychopathology.

The long-term effects of exposure to blast overpressure are an important health concern in military personnel. Increase in amyloid beta (Aβ) has been documented after non-blast traumatic brain injury (TBI) and may contribute to neuropathology and an increased risk for Alzheimer's disease. We have shown that Aβ levels decrease following exposure to a low-intensity blast overpressure event. To further explore this observation, we examined the effects of a single 37 kPa (5.4 psi) blast exposure on brain Aβ levels, production, and clearance mechanisms in the acute (24 h) and delayed (28 days) phases post-blast exposure in an experimental rat model. Aβ and, notably, the highly neurotoxic detergent soluble Aβ42 form, was reduced at 24 h but not 28 days after blast exposure. This reduction was not associated with changes in the levels of Aβ oligomers, expression levels of amyloid precursor protein (APP), or increase in enzymes involved in the amyloidogenic cleavage of APP, the β- and ϒ-secretases BACE1 and presenilin-1, respectively. The levels of ADAM17 α-secretase (also known as tumor necrosis factor α-converting enzyme) decreased, concomitant with the reduction in brain Aβ. Additionally, significant increases in brain levels of the endothelial transporter, low-density related protein 1 (LRP1), and enhancement in co-localization of aquaporin-4 (AQP4) to perivascular astrocytic end-feet were observed 24 h after blast exposure. These findings suggest that exposure to low-intensity blast may enhance endothelial clearance of Aβ by LRP1-mediated transcytosis and alter AQP4-aided glymphatic clearance. Collectively, the data demonstrate that low-intensity blast alters enzymatic, transvascular, and perivascular clearance of Aβ.

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.

Binge drinking is rising among aged adults (>65 years of age), however the contribution of alcohol misuse to neurodegenerative disease development is not well understood. Both advanced age and repeated binge ethanol exposure increase neuroinflammation, which is an important component of neurodegeneration and cognitive dysfunction. Surprisingly, the distinct effects of binge ethanol exposure on neuroinflammation and associated degeneration in the aged brain have not been well characterized. Here, we establish a model of intermittent binge ethanol exposure in young and aged female mice to investigate the effects of advanced age and binge ethanol on these outcomes. Following intermittent binge ethanol exposure, expression of pro-inflammatory mediators (tnf-α, il-1β, ccl2) was distinctly increased in isolated hippocampal tissue by the combination of advanced age and ethanol. Binge ethanol exposure also increased measures of senescence, the nod like receptor pyrin domain containing 3 (NLRP3) inflammasome, and microglia reactivity in the brains of aged mice compared to young. Binge ethanol exposure also promoted neuropathology in the hippocampus of aged mice, including tau hyperphosphorylation and neuronal death. We further identified advanced age-related deficits in contextual memory that were further negatively impacted by ethanol exposure. These data suggest binge drinking superimposed with advanced age promotes early markers of neurodegenerative disease development and cognitive decline, which may be driven by heightened neuroinflammatory responses to ethanol. Taken together, we propose this novel exposure model of intermittent binge ethanol can be used to identify therapeutic targets to prevent advanced age- and ethanol-related neurodegeneration.

Crime-related spiking of alcoholic drinks with prescription drugs is quite common and has been happening for centuries. This study, therefore, evaluated the effects of oral administration of alcohol spiked with the zolpidem and midazolam potent sedatives on inflammation, oxidative stress and various organ damage in male Swiss albino mice.

Mice were randomly assigned into six treatment groups; the first group constituted the normal control, the second group received 50 mg/kg body weight of zolpidem only, the third group received 50 mg/kg body weight zolpidem dissolved in 5 g/kg alcohol, the fourth group received 50 mg/kg midazolam only, the fifth group received midazolam (50 mg/kg) dissolved in 5 g/kg alcohol and the sixth group received 5 g/kg alcohol.

Alcohol-induced significant reduction in neurological function and altered blood hematological indicators. Such neurological impairment and negative effects on blood were exacerbated in mice administered with spiked alcohol. Additionally, midazolam and zolpidem enhanced alcohol-driven elevation of liver function markers; the serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) gamma glutamyltransferase (GGT), total bilirubin and alkaline phosphatase. Exposure to alcohol and/or spiked alcohol led to significant augmentation of nitric oxide and malonaldehyde, with concomitant depletion of liver glutathione (GSH) levels. Similarly, serum levels of pro-inflammatory cytokines tumor necrosis factor alpha and interferon-gamma were increased by co-exposure with midazolam or zolpidem. Alcohol-induced hepatotoxicity and nephrotoxicity were amplified by exposure to alcohol spiked with midazolam/zolpidem.

Exposure to alcohol spiked with midazolam or zolpidem appears to exacerbate neurological deficits, inflammation, oxidative stress, and organ damage.

Oxidative stress and neuroinflammation are involved in the pathogenesis of alcohol addiction. However, little is known regarding the effect of genetic, behavioral, psychological, and environmental sources of origin on the inflammation and oxidative stress pathways of patients with alcohol addiction. Our study aimed to evaluate the impact of selected common functional single-nucleotide polymorphisms in inflammation and oxidative stress genes on alcohol addiction, and common comorbid psychosymptomatology. Our study included 89 hospitalized alcohol-addicted patients and 93 healthy individuals, all Slovenian males. Their DNA was isolated from peripheral blood and patients were genotyped for PON1 rs705379, rs705381, rs854560, and rs662, SOD2 rs4880, GPX1 rs1050450, IL1B rs1143623, rs16944, and rs1071676, IL6 rs1800795, IL6R rs2228145, and miR146a rs2910164. Kruskal-Wallis and Mann-Whitney tests were used for the additive and dominant genetic models, respectively. Our findings suggested the involvement of IL6 rs1800795 in alcohol addiction. Moreover, our data indicated that the genetic variability of SOD2 and PON1, as well as IL1B and IL6R, may be related to comorbid psychosymptomatology, revealing a potential indirect means of association of both the oxidative stress and inflammation pathways.

The endocannabinoidome (eCBome) is the expanded endocannabinoid system (ECS) and studies show that there is a link between this system and how it modulates alcohol induced neuroinflammation. Using conditional knockout (cKO) mice with selective deletion of cannabinoid type 2 receptors (CB2Rs) in dopamine neurons (DAT-Cnr2) and in microglia (Cx3Cr1-Cnr2), we investigated how CB2Rs modulate behavioral and neuroinflammation induced by alcohol. Behavioral tests including locomotor and wheel running activity, rotarod performance test, and alcohol preference tests were used to evaluate behavioral changes induced by alcohol. Using ELISA assay, we investigated the level of pro-inflammatory cytokines, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1α (IL-1α), and interleukin-1β (IL-1β) in the hippocampus of mice. The findings demonstrated that locomotor activity, wheel running, and rotarod performance activities were significantly affected by cell-type specific deletion of CB2Rs in dopamine neurons and microglia. The non-selective CB2R agonist, WIN 55,212-2, reduced alcohol preference in the wild type and cell-type specific CB2R cKO mice. In addition, the result showed that cell-type specific deletion of CB2Rs per se and administration of alcohol to CB2R cKO mice increased the expression of proinflammatory cytokines in the hippocampus. These findings suggest the involvement of CB2Rs in modulating behavioral and immune alterations induced by alcohol.

Adolescent binge drinking increases Toll-like receptor 4 (TLR4), receptor for advanced glycation end products (RAGE), the endogenous TLR4/RAGE agonist high-mobility group box 1 (HMGB1), and proinflammatory neuroimmune signaling in the adult basal forebrain in association with persistent reductions of basal forebrain cholinergic neurons (BFCNs). In vivo preclinical adolescent intermittent ethanol (AIE) studies find anti-inflammatory interventions post-AIE reverse HMGB1-TLR4/RAGE neuroimmune signaling and loss of BFCNs in adulthood, suggesting proinflammatory signaling causes epigenetic repression of the cholinergic neuron phenotype. Reversible loss of BFCN phenotype in vivo is linked to increased repressive histone 3 lysine 9 dimethylation (H3K9me2) occupancy at cholinergic gene promoters, and HMGB1-TLR4/RAGE proinflammatory signaling is linked to epigenetic repression of the cholinergic phenotype. Using an ex vivo basal forebrain slice culture (FSC) model, we report EtOH recapitulates the in vivo AIE-induced loss of ChAT+IR BFCNs, somal shrinkage of the remaining ChAT+ neurons, and reduction of BFCN phenotype genes. Targeted inhibition of EtOH-induced proinflammatory HMGB1 blocked ChAT+IR loss while disulfide HMBG1-TLR4 and fully reduced HMGB1-RAGE signaling decreased ChAT+IR BFCNs. EtOH increased expression of the transcriptional repressor RE1-silencing transcription factor (REST) and the H3K9 methyltransferase G9a that was accompanied by increased repressive H3K9me2 and REST occupancy at promoter regions of the BFCN phenotype genes Chat and Trka as well as the lineage transcription factor Lhx8. REST expression was similarly increased in the post-mortem human basal forebrain of individuals with alcohol use disorder, which is negatively correlated with ChAT expression. Administration of REST siRNA and the G9a inhibitor UNC0642 blocked and reversed the EtOH-induced loss of ChAT+IR BFCNs, directly linking REST-G9a transcriptional repression to suppression of the cholinergic neuron phenotype. These data suggest that EtOH induces a novel neuroplastic process involving neuroimmune signaling and transcriptional epigenetic gene repression resulting in the reversible suppression of the cholinergic neuron phenotype.

Both excessive alcohol consumption and exposure to high levels of arsenic can lead to neurodegeneration, especially in the hippocampus. Co-exposure to arsenic and alcohol can occur because an individual with an Alcohol Use Disorder (AUD) is exposed to arsenic in their drinking water or food or because of arsenic found directly in alcoholic beverages. This study aims to determine if co-exposure to alcohol and arsenic leads to worse outcomes in neurodegeneration and associated mechanisms that could lead to cell death. To study this, mice were exposed to a 10-day gavage model of alcohol-induced neurodegeneration with varying doses of arsenic (0, 0.005, 2.5, or 10 mg/kg). The following were examined after the last dose of ethanol: (1) microglia activation assessed via immunohistochemical detection of Iba-1, (2) reactive oxygen and nitrogen species (ROS/RNS) using a colorimetric assay, (3) neurodegeneration using Fluoro-Jade® C staining (FJC), and 4) arsenic absorption using ICP-MS. After exposure, there was an additive effect of the highest dose of arsenic (10 mg/kg) in the dentate gyrus of alcohol-induced FJC+ cells. This additional cell loss may have been due to the observed increase in microglial reactivity or increased arsenic absorption following co-exposure to ethanol and arsenic. The data also showed that arsenic caused an increase in CYP2E1 expression and ROS/RNS production in the hippocampus which could have independently contributed to increased neurodegeneration. Altogether, these findings suggest a potential cyclical impact of co-exposure to arsenic and ethanol as ethanol increases arsenic absorption but arsenic also enhances alcohol's deleterious effects in the CNS.

The most common neurodegenerative diseases (NDDs), such as Alzheimer's disease (AD) and Parkinson's disease (PD), are the seventh leading cause of mortality and morbidity in developed countries. Clinical observations of NDD patients are characterized by a progressive loss of neurons in the brain along with memory decline. The common pathological hallmarks of NDDs include oxidative stress, the dysregulation of calcium, protein aggregation, a defective protein clearance system, mitochondrial dysfunction, neuroinflammation, neuronal apoptosis, and damage to cholinergic neurons. Therefore, managing this pathology requires screening drugs with different pathological targets, and suitable drugs for slowing the progression or prevention of NDDs remain to be discovered. Among the pharmacological strategies used to manage NDDs, natural drugs represent a promising therapeutic strategy. This review discusses the neuroprotective potential of seaweed and its bioactive compounds, and safety issues, which may provide several beneficial insights that warrant further investigation.

Affective disorders, including anxiety and depression, developed in adult offspring of the mothers who consumed alcohol during pregnancy could be associated with an imbalance in neuroimmune factors in the amygdala (corpus amygdaloideum) resulted in impaired emotional stimulus processing. The aim of this study was to compare the content of cytokines TNF-α, IL-1α, IL-1β, IL-10, and IL-17 in the amygdala of adult female rats exposed to alcohol in utero and control rats. Cytokine levels were evaluated using a multiplex immunoassay system; mRNA expression was investigated using a real-time reverse transcription-polymerase chain reaction (RT-qPCR) assay. Prenatal alcohol exposure led to the increase in the content of TNF-α and IL-1β without significant changes in the mRNA expression level. Our data suggest that ethanol exposure to the fetus during pregnancy can result in long-term alterations in the content of the key neuroinflammatory factors in the amygdala, which in turn can be a risk factor for affective disorders in the adulthood.

Recent evidence suggests that alcohol use disorder (AUD) may manifest itself differently in women compared to men. Women experience AUDs on an accelerated timeline and may have certain regional vulnerabilities. In male rats, neuronal cell death and astrocyte reactivity are noted following induction of alcohol dependence in an animal model of an AUD. However, the regional and temporal patterns of neurodegeneration and astrocyte reactivity have yet to be fully examined in females using this model. Therefore, adult female rats were exposed to a 4-day binge model of alcohol dependence followed by different periods of abstinence. Histological markers for FluoroJade B, a label of degenerating neurons, and vimentin, a marker for reactive astrocytes, were utilized. The expression of these markers in cortical and limbic regions was quantified immediately after their last dose (e.g., T0), or 2, 7, and 14 days later. Significant neuronal cell death was noted in the entorhinal cortex and the hippocampus, similar to previous reports in males, but also in several cortical regions not previously observed. Vimentin immunoreactivity was noted in the same regions as previously reported, in addition to three novel regions. Vimentin immunoreactivity also occurred at earlier and later time points in some cortical and hippocampal regions. These data suggest that both neuronal cell death and astrocyte reactivity could be more widespread in females compared to males. Therefore, this study provides a framework for specific regions and time points which should be examined in future studies of alcohol-induced damage that include female rats.

High ethanol consumption triggers neuroinflammation, implicated in sustaining chronic alcohol use. This inflammation boosts glutamate, prompting dopamine release in reward centers, driving prolonged drinking and relapse. Fibrate drugs, activating peroxisome proliferator-activated receptor alpha (PPAR-α), counteract neuroinflammation in other contexts, prompting investigation into their impact on ethanol-induced inflammation. Here, we studied, in UChB drinker rats, whether the administration of fenofibrate in the withdrawal stage after chronic ethanol consumption reduces voluntary intake when alcohol is offered again to the animals (relapse-type drinking). Furthermore, we determined if fenofibrate was able to decrease ethanol-induced neuroinflammation and oxidative stress in the brain. Animals treated with fenofibrate decreased alcohol consumption by 80% during post-abstinence relapse. Furthermore, fenofibrate decreased the expression of the proinflammatory cytokines tumor necrosis factor-alpha (TNF-α) and interleukins IL-1β and IL-6, and of an oxidative stress-induced gene (heme oxygenase-1), in the hippocampus, nucleus accumbens, and prefrontal cortex. Animals treated with fenofibrate showed an increase M2-type microglia (with anti-inflammatory proprieties) and a decrease in phagocytic microglia in the hippocampus. A PPAR-α antagonist (GW6471) abrogated the effects of fenofibrate, indicating that they are dependent on PPAR-α activation. These findings highlight the potential of fenofibrate, an FDA-approved dyslipidemia medication, as a supplementary approach to alleviating relapse severity in individuals with alcohol use disorder (AUD) during withdrawal.