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Crews FT, Coleman LG, Macht VA, Vetreno RP. Alcohol, HMGB1, and Innate Immune Signaling in the Brain. Alcohol Res 2024; 44:04. [PMID: 39135668 PMCID: PMC11318841 DOI: 10.35946/arcr.v44.1.04] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2024] Open
Abstract
PURPOSE 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. SEARCH METHODS The authors used the search terms "HMGB1 protein," "alcohol," and "brain" across PubMed, Scopus, and Embase to find articles published between 1991 and 2023. SEARCH RESULTS The database search found 54 references in PubMed, 47 in Scopus, and 105 in Embase. A total of about 100 articles were included. DISCUSSION AND CONCLUSIONS 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.
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Affiliation(s)
- Fulton T. Crews
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, North Carolina
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
- Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Leon G. Coleman
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, North Carolina
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Victoria A. Macht
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Ryan P. Vetreno
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, North Carolina
- Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, North Carolina
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Balan I, Grusca A, Chéry SL, Materia BR, O’Buckley TK, Morrow AL. Neurosteroid [3α,5α]-3-Hydroxy-pregnan-20-one Enhances the CX3CL1-CX3CR1 Pathway in the Brain of Alcohol-Preferring Rats with Sex-Specificity. Life (Basel) 2024; 14:860. [PMID: 39063614 PMCID: PMC11277648 DOI: 10.3390/life14070860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 06/04/2024] [Accepted: 07/03/2024] [Indexed: 07/28/2024] Open
Abstract
This study investigates the impact of allopregnanolone ([3α,5α]3-hydroxypregnan-20-one or 3α,5α-tetrahydroprogesterone (3α,5α-THP); 10 mg/kg, IP) on fractalkine/CX3-C motif chemokine ligand 1 (CX3CL1) levels, associated signaling components, and markers for microglial and astrocytic cells in the nucleus accumbens (NAc) of male and female alcohol-preferring (P) rats. Previous research suggested that 3α,5α-THP enhances anti-inflammatory interleukin-10 (IL-10) cytokine production in the brains of male P rats, with no similar effect observed in females. This study reveals that 3α,5α-THP elevates CX3CL1 levels by 16% in the NAc of female P rats, with no significant changes observed in males. The increase in CX3CL1 levels induced by 3α,5α-THP was observed in females across multiple brain regions, including the NAc, amygdala, hypothalamus, and midbrain, while no significant effect was noted in males. Additionally, female P rats treated with 3α,5α-THP exhibited notable increases in CX3CL1 receptor (CX3CR1; 48%) and transforming growth factor-beta 1 (TGF-β1; 24%) levels, along with heightened activation (phosphorylation) of signal transducer and activator of transcription 1 (STAT1; 85%) in the NAc. Conversely, no similar alterations were observed in male P rats. Furthermore, 3α,5α-THP decreased glial fibrillary acidic protein (GFAP) levels by 19% in both female and male P rat NAc, without affecting microglial markers ionized calcium-binding adaptor molecule 1 (IBA1) and transmembrane protein 119 (TMEM119). These findings indicate that 3α,5α-THP enhances the CX3CL1/CX3CR1 pathway in the female P rat brain but not in males, primarily influencing astrocyte reactivity, with no observed effect on microglial activation.
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Affiliation(s)
- Irina Balan
- Bowles Center for Alcohol Studies, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (I.B.)
- Department of Psychiatry, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Adelina Grusca
- Bowles Center for Alcohol Studies, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (I.B.)
| | - Samantha Lucenell Chéry
- Bowles Center for Alcohol Studies, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (I.B.)
- Neuroscience Curriculum, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Baylee R. Materia
- Bowles Center for Alcohol Studies, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (I.B.)
| | - Todd K. O’Buckley
- Bowles Center for Alcohol Studies, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (I.B.)
| | - A. Leslie Morrow
- Bowles Center for Alcohol Studies, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (I.B.)
- Department of Psychiatry, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Pharmacology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Balan I, Boero G, Chéry SL, McFarland MH, Lopez AG, Morrow AL. Neuroactive Steroids, Toll-like Receptors, and Neuroimmune Regulation: Insights into Their Impact on Neuropsychiatric Disorders. Life (Basel) 2024; 14:582. [PMID: 38792602 PMCID: PMC11122352 DOI: 10.3390/life14050582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/18/2024] [Accepted: 04/28/2024] [Indexed: 05/26/2024] Open
Abstract
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.
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Affiliation(s)
- Irina Balan
- Bowles Center for Alcohol Studies, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (I.B.); (S.L.C.); (M.H.M.); (A.G.L.)
- Department of Psychiatry, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Giorgia Boero
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA;
| | - Samantha Lucenell Chéry
- Bowles Center for Alcohol Studies, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (I.B.); (S.L.C.); (M.H.M.); (A.G.L.)
- Neuroscience Curriculum, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Minna H. McFarland
- Bowles Center for Alcohol Studies, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (I.B.); (S.L.C.); (M.H.M.); (A.G.L.)
- Neuroscience Curriculum, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Alejandro G. Lopez
- Bowles Center for Alcohol Studies, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (I.B.); (S.L.C.); (M.H.M.); (A.G.L.)
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - A. Leslie Morrow
- Bowles Center for Alcohol Studies, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (I.B.); (S.L.C.); (M.H.M.); (A.G.L.)
- Department of Psychiatry, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Pharmacology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Airapetov M, Eresko S, Ignatova P, Lebedev A, Bychkov E, Shabanov P. Effect of rifampicin on TLR4-signaling pathways in the nucleus accumbens of the rat brain during abstinence of long-term alcohol treatment. Alcohol Alcohol 2024; 59:agae016. [PMID: 38520481 DOI: 10.1093/alcalc/agae016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 02/03/2024] [Accepted: 02/19/2024] [Indexed: 03/25/2024] Open
Abstract
AIMS The treatment with the antibiotic rifampicin (Rif) led to a decrease in the frequency of neurodegenerative pathologies. There are suggestions that the mechanism of action of Rif may be mediated by its effect on toll-like receptor (TLR)4-dependent pathways. We evaluated the expression status of TLR4-dependent genes during abstinence from long-term alcohol treatments in the nucleus accumbens (NAc) of the rat brain, and also studied the effects of Rif to correct these changes. METHODS The long-term alcohol treatment was performed by intragastric delivery of ethanol solution. At the end of alcohol treatment intraperitoneal injections of Rif (100 mg/kg) or saline were made. Extraction of the brain structures was performed on the 10th day of abstinence from alcohol. We used the SYBR Green qPCR method to quantitatively analyze the relative expression levels of the studied genes. RESULTS The long-term alcohol treatment promotes an increase in the level of TLR4 mRNA and mRNA of its endogenous ligand high-mobility group protein B1 during abstinence drop alcohol in NAc of rats. The use of Rif in our study led to a decrease in the increased expression of high-mobility group protein B1, Tlr4, and proinflammatory cytokine genes (Il1β, Il6) in the NAc of the rat brain during abstinence of long-term alcohol treatment. In addition, Rif administration increased the decreased mRNA levels of anti-inflammatory cytokines (Il10, Il11). CONCLUSION The data obtained indicate the ability of Rif to correct the mechanisms of the TLR4 system genes in the NAc of the rat brain during alcohol abstinence.
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Affiliation(s)
- Marat Airapetov
- Department of Neuropharmacology, Institute of Experimental Medicine, P.O. Box 197376, 12 Academician Pavlova str., St. Petersburg, Russian Federation
- Department of Pathological Physiology, Military Medical Academy of S.M. Kirov, P.O. Box 194044, 6G Akademika Lebedeva str., St. Petersburg, Russian Federation
| | - Sergei Eresko
- Department of Neuropharmacology, Institute of Experimental Medicine, P.O. Box 197376, 12 Academician Pavlova str., St. Petersburg, Russian Federation
- Center for Chemical Engineering, Saint-Petersburg National Research University of Information Technologies, Mechanics and Optics, P.O. Box 197101, 49 Kronverksky pr., St. Petersburg, Russian Federation
| | - Polina Ignatova
- Department of Neuropharmacology, Institute of Experimental Medicine, P.O. Box 197376, 12 Academician Pavlova str., St. Petersburg, Russian Federation
| | - Andrei Lebedev
- Department of Neuropharmacology, Institute of Experimental Medicine, P.O. Box 197376, 12 Academician Pavlova str., St. Petersburg, Russian Federation
| | - Evgenii Bychkov
- Department of Neuropharmacology, Institute of Experimental Medicine, P.O. Box 197376, 12 Academician Pavlova str., St. Petersburg, Russian Federation
| | - Petr Shabanov
- Department of Neuropharmacology, Institute of Experimental Medicine, P.O. Box 197376, 12 Academician Pavlova str., St. Petersburg, Russian Federation
- Department of Pathological Physiology, Military Medical Academy of S.M. Kirov, P.O. Box 194044, 6G Akademika Lebedeva str., St. Petersburg, Russian Federation
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Morrow AL, Boero G, Balan I. Emerging evidence for endogenous neurosteroid modulation of pro-inflammatory and anti-inflammatory pathways that impact neuropsychiatric disease. Neurosci Biobehav Rev 2024; 158:105558. [PMID: 38244954 DOI: 10.1016/j.neubiorev.2024.105558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 12/01/2023] [Accepted: 01/16/2024] [Indexed: 01/22/2024]
Abstract
This mini-review presents emerging evidence that endogenous neurosteroids modulate both pro- and anti-inflammatory signaling by immune cells and brain cells that contribute to depression, alcohol use disorders, and other inflammatory conditions. We first review the literature on pregnenolone and allopregnanolone inhibition of proinflammatory neuroimmune pathways in the periphery and the brain - effects that are independent of GABAergic mechanisms. We follow with evidence for neurosteroid enhancement of anti-inflammatory and protective pathways in brain and immune cells. These studies draw clinical relevance from a large body of evidence that pro-inflammatory immune signaling is dysregulated in many brain disorders and the fact that neurosteroids inhibit the same inflammatory pathways that are activated in depression, alcohol use disorders and other inflammatory conditions. Thus, we describe evidence that neurosteroid levels are decreased and neurosteroid supplementation has therapeutic efficacy in these neuropsychiatric conditions. We conclude with a perspective that endogenous regulation of immune balance between pro- and anti-inflammatory pathways by neurosteroid signaling is essential to prevent the onset of disease. Deficits in neurosteroids may unleash excessive pro-inflammatory activation which progresses in a feed-forward manner to disrupt brain networks that regulate stress, emotion and motivation. Neurosteroids can block various inflammatory pathways in mouse and human macrophages, rat brain and human blood and therefore provide new hope for treatment of intractable conditions that involve excessive inflammatory signaling.
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Affiliation(s)
- A Leslie Morrow
- Department of Psychiatry and Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | - Giorgia Boero
- Department of Psychiatry and Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Irina Balan
- Department of Psychiatry and Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Balan I, Grusca A, O’Buckley TK, Morrow AL. Neurosteroid [3α,5α]-3-hydroxy-pregnan-20-one enhances IL-10 production via endosomal TRIF-dependent TLR4 signaling pathway. Front Endocrinol (Lausanne) 2023; 14:1299420. [PMID: 38179300 PMCID: PMC10765172 DOI: 10.3389/fendo.2023.1299420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 11/24/2023] [Indexed: 01/06/2024] Open
Abstract
Background Previous studies demonstrated the inhibitory effect of allopregnanolone (3α,5α-THP) on the activation of inflammatory toll-like receptor 4 (TLR4) signals in RAW264.7 macrophages and the brains of selectively bred alcohol-preferring (P) rats. In the current study, we investigated the impact of 3α,5α-THP on the levels of IL-10 and activation of the TRIF-dependent endosomal TLR4 pathway. Methods The amygdala and nucleus accumbens (NAc) of P rats, which exhibit innately activated TLR4 pathways as well as RAW264.7 cells, were used. Enzyme-linked immunosorbent assays (ELISA) and immunoblotting assays were used to ascertain the effects of 3α,5α-THP on the TRIF-dependent endosomal TLR4 pathway and endosomes were isolated to examine translocation of TLR4 and TRIF. Additionally, we investigated the effects of 3α,5α-THP and 3α,5α-THDOC (0.1, 0.3, and 1.0 µM) on the levels of IL-10 in RAW264.7 macrophages. Finally, we examined whether inhibiting TRIF (using TRIF siRNA) in RAW264.7 cells altered the levels of IL-10. Results 3α,5α-THP administration facilitated activation of the endosomal TRIF-dependent TLR4 pathway in males, but not female P rats. 3α,5α-THP increased IL-10 levels (+13.2 ± 6.5%) and BDNF levels (+21.1 ± 11.5%) in the male amygdala. These effects were associated with increases in pTRAM (+86.4 ± 28.4%), SP1 (+122.2 ± 74.9%), and PI(3)K-p110δ (+61.6 ± 21.6%), and a reduction of TIRAP (-13.7 ± 6.0%), indicating the activation of the endosomal TRIF-dependent TLR4 signaling pathway. Comparable effects were observed in NAc of these animals. Furthermore, 3α,5α-THP enhanced the accumulation of TLR4 (+43.9 ± 11.3%) and TRIF (+64.8 ± 32.8%) in endosomes, with no significant effect on TLR3 accumulation. Additionally, 3α,5α-THP facilitated the transition from early endosomes to late endosomes (increasing Rab7 levels: +35.8 ± 18.4%). In RAW264.7 cells, imiquimod (30 µg/mL) reduced IL-10 while 3α,5α-THP and 3α,5α-THDOC (0.1, 0.3, and 1.0 µM) restored IL-10 levels. To determine the role of the TRIF-dependent TLR4 signaling pathway in IL-10 production, the downregulation of TRIF (-62.9 ± 28.2%) in RAW264.7 cells led to a reduction in IL-10 levels (-42.3 ± 8.4%). TRIF (-62.9 ± 28.2%) in RAW264.7 cells led to a reduction in IL-10 levels (-42.3 ± 8.4%) and 3α,5α-THP (1.0 µM) no longer restored the reduced IL-10 levels. Conclusion The results demonstrate 3α,5α-THP enhancement of the endosomal TLR4-TRIF anti-inflammatory signals and elevations of IL-10 in male P rat brain that were not detected in female P rat brain. These effects hold significant implications for controlling inflammatory responses in both the brain and peripheral immune cells.
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Affiliation(s)
- Irina Balan
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Adelina Grusca
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Todd K. O’Buckley
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - A. Leslie Morrow
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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Airapetov MI, Eresko SO, Skabelkin DA, Iskalieva AR, Lebedev AA, Bychkov ER, Shabanov PD. [The effect of rifampicin on the system of Toll-like receptors in the nucleus accumbens of the brain of long-term alcoholized rats during alcohol withdrawal]. BIOMEDITSINSKAIA KHIMIIA 2022; 68:279-287. [PMID: 36005846 DOI: 10.18097/pbmc20226804279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Nucleus accumbens (NAc) is the ventral part of the striatum of the brain; it is an important part of the mesolimbic pathway involved in the reward system that mediates the formation of various forms of addiction, in particular alcohol addiction. Neuroimaging data and in vitro studies indicate the development of a pronounced neurodegenerative process in the NAc, with long-term alcohol use, but the key mechanisms mediating this process remain unknown. In recent years, the attention of researchers has been focused on studying the system of Toll-like receptors (TLRs), the increased activity of which is clearly shown in the cerebral cortex and hippocampus during prolonged alcohol exposure, but there is a need to study the role of this system in other brain structures. In this study, we have shown that prolonged alcohol exposure (2 months) with moderate doses of ethanol (2 g/kg) promotes a pronounced increase in the expression of the Tlr4 gene and its endogenous ligand Hmgb1 in NAc during the period of alcohol withdrawal in rats. Injections of rifampicin (100 mg/kg) reduced the elevated expression level of Hmgb1, Tlr4, as well as pro-inflammatory cytokine genes (IL1β, IL6), while the administration of the drug increased the reduced level of mRNA of anti-inflammatory cytokines (IL10, IL11).
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Affiliation(s)
- M I Airapetov
- Department of Neuropharmacology, Institute of Experimental Medicine, St. Petersburg, Russia; Department of Pharmacology, St. Petersburg State Pediatric Medical University
| | - S O Eresko
- Department of Neuropharmacology, Institute of Experimental Medicine, St. Petersburg, Russia; Research and Training Center of Molecular and Cellular Technologies, St. Petersburg, Russia
| | - D A Skabelkin
- Department of Neuropharmacology, Institute of Experimental Medicine, St. Petersburg, Russia
| | - A R Iskalieva
- Department of Neuropharmacology, Institute of Experimental Medicine, St. Petersburg, Russia
| | - A A Lebedev
- Department of Neuropharmacology, Institute of Experimental Medicine, St. Petersburg, Russia
| | - E R Bychkov
- Department of Neuropharmacology, Institute of Experimental Medicine, St. Petersburg, Russia
| | - P D Shabanov
- Department of Neuropharmacology, Institute of Experimental Medicine, St. Petersburg, Russia; Department of Pharmacology, Kirov Military Medical Academy, St. Petersburg, Russia
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Astrocytes play a critical role in mediating the effect of acute ethanol on central amygdala glutamatergic transmission. Neuropharmacology 2022; 205:108918. [PMID: 34896402 PMCID: PMC8792276 DOI: 10.1016/j.neuropharm.2021.108918] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 12/02/2021] [Accepted: 12/06/2021] [Indexed: 11/21/2022]
Abstract
The Central Amygdala (CeA) has been heavily implicated in many aspects of alcohol use disorder. Ethanol (EtOH) has been shown to modulate glutamatergic transmission in the lateral subdivision of the CeA, however, the exact mechanism of this modulation is still unclear. EtOH exposure is associated with increased pro-inflammatory cytokines in the CeA, and inhibition of neuroimmune cells (microglia and astrocytes) has previously been shown to reduce EtOH drinking in animal models. Since neuroimmune activation seems to be involved in many of the effects of EtOH, we hypothesized that acute EtOH exposure will increase excitatory glutamatergic transmission in the CeA via modulation of neuroimmune cells. Using ex vivo brain slice whole-cell patch clamp electrophysiology, it was found that a physiologically relevant concentration of EtOH (20 mM) significantly increased presynaptic glutamatergic transmission in the CeA. Pharmacologic and chemogenetic inhibition of astrocyte function significantly reduced the ability of EtOH to modulate CeA glutamatergic transmission with minimal impact of microglia inhibition. This finding prompted additional studies examining whether direct neuroimmune activation through lipopolysaccharide (LPS) might lead to an increase in the glutamatergic transmission in the CeA. It was found that LPS modulation of glutamatergic transmission was limited by microglia activation and required astrocyte signaling. Taken together these results support the hypothesis that acute EtOH enhances lateral CeA glutamatergic transmission through an astrocyte mediated mechanism.
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Morrow AL, Balan I, Boero G. Mechanisms Underlying Recovery From Postpartum Depression Following Brexanolone Therapy. Biol Psychiatry 2022; 91:252-253. [PMID: 34961596 DOI: 10.1016/j.biopsych.2021.11.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 11/05/2021] [Indexed: 11/02/2022]
Affiliation(s)
- A Leslie Morrow
- Departments of Psychiatry and Pharmacology and the Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, North Carolina.
| | - Irina Balan
- Departments of Psychiatry and Pharmacology and the Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Giorgia Boero
- Departments of Psychiatry and Pharmacology and the Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, North Carolina
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Meredith LR, Burnette EM, Grodin EN, Irwin MR, Ray LA. Immune treatments for alcohol use disorder: A translational framework. Brain Behav Immun 2021; 97:349-364. [PMID: 34343618 PMCID: PMC9044974 DOI: 10.1016/j.bbi.2021.07.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 07/10/2021] [Accepted: 07/28/2021] [Indexed: 12/14/2022] Open
Abstract
While the immune system is essential for survival, an excessive or prolonged inflammatory response, such as that resulting from sustained heavy alcohol use, can damage the host and contribute to psychiatric disorders. A growing body of literature indicates that the immune system plays a critical role in the development and maintenance of alcohol use disorder (AUD). As such, there is enthusiasm for treatments that can restore healthy levels of inflammation as a mechanism to reduce drinking and promote recovery. In this qualitative literature review, we provide a conceptual rationale for immune therapies and discuss progress in medications development for AUD focused on the immune system as a treatment target. This review is organized into sections based on primary signaling pathways targeted by the candidate therapies, namely: (a) toll-like receptors, (b) phosphodiesterase inhibitors, (c) peroxisome proliferator-activated receptors, (d) microglia and astrocytes, (e) other immune pharmacotherapies, and (f) behavioral therapies. As relevant within each section, we examine the basic biological mechanisms of each class of therapy and evaluate preclinical research testing the role of the therapy on mitigating alcohol-related behaviors in animal models. To the extent available, translational findings are reviewed with discussion of completed and ongoing randomized clinical trials and their findings to date. An applied and clinically focused approach is taken to identify the potential clinical applications of the various treatments reviewed. We conclude by delineating the most promising candidate treatments and discussing future directions by considering opportunities for immune treatment development and personalized medicine for AUD.
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Affiliation(s)
- Lindsay R Meredith
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Elizabeth M Burnette
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Erica N Grodin
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Michael R Irwin
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA, USA; Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, USA; Jane and Terry Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles, Los Angeles, CA, USA; Cousins Center for Psychoneuroimmunology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Lara A Ray
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA, USA; Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, USA.
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11
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Possible mechanisms of HIV neuro-infection in alcohol use: Interplay of oxidative stress, inflammation, and energy interruption. Alcohol 2021; 94:25-41. [PMID: 33864851 DOI: 10.1016/j.alcohol.2021.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 03/05/2021] [Accepted: 04/01/2021] [Indexed: 11/21/2022]
Abstract
Alcohol use and HIV-1 infection have a pervasive impact on brain function, which extends to the requirement, distribution, and utilization of energy within the central nervous system. This effect on neuroenergetics may explain, in part, the exacerbation of HIV-1 disease under the influence of alcohol, particularly the persistence of HIV-associated neurological complications. The objective of this review article is to highlight the possible mechanisms of HIV/AIDS progression in alcohol users from the perspective of oxidative stress, neuroinflammation, and interruption of energy metabolism. These include the hallmark of sustained immune cell activation and high metabolic energy demand by HIV-1-infected cells in the central nervous system, with at-risk alcohol use. Here, we discussed the point that the increase in energy supply requirement by HIV-1-infected neuroimmune cells as well as the deterrence of nutrient uptake across the blood-brain barrier significantly depletes the energy source and neuro-environment homeostasis in the CNS. We also described the mechanistic idea that comorbidity of HIV-1 infection and alcohol use can cause a metabolic shift and redistribution of energy usage toward HIV-1-infected neuroimmune cells, as shown in neuropathological evidence. Under such an imbalanced neuro-environment, meaningless energy waste is expected in infected cells, along with unnecessary malnutrition in non-infected neuronal cells, which is likely to accelerate HIV neuro-infection progression in alcohol use. Thus, it will be important to consider the factor of nutrients/energy imbalance in formulating treatment strategies to help impede the progression of HIV-1 disease and associated neurological disorders in alcohol use.
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12
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Pairing Binge Drinking and a High-Fat Diet in Adolescence Modulates the Inflammatory Effects of Subsequent Alcohol Consumption in Mice. Int J Mol Sci 2021; 22:ijms22105279. [PMID: 34067897 PMCID: PMC8157004 DOI: 10.3390/ijms22105279] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 05/08/2021] [Accepted: 05/15/2021] [Indexed: 12/12/2022] Open
Abstract
Alcohol binge drinking (BD) and poor nutritional habits are two frequent behaviors among many adolescents that alter gut microbiota in a pro-inflammatory direction. Dysbiotic changes in the gut microbiome are observed after alcohol and high-fat diet (HFD) consumption, even before obesity onset. In this study, we investigate the neuroinflammatory response of adolescent BD when combined with a continuous or intermittent HFD and its effects on adult ethanol consumption by using a self-administration (SA) paradigm in mice. The inflammatory biomarkers IL-6 and CX3CL1 were measured in the striatum 24 h after BD, 3 weeks later and after the ethanol (EtOH) SA. Adolescent BD increased alcohol consumption in the oral SA and caused a greater motivation to seek the substance. Likewise, mice with intermittent access to HFD exhibited higher EtOH consumption, while the opposite effect was found in mice with continuous HFD access. Biochemical analyses showed that after BD and three weeks later, striatal levels of IL-6 and CX3CL1 were increased. In addition, in saline-treated mice, CX3CL1 was increased after continuous access to HFD. After oral SA procedure, striatal IL-6 was increased only in animals exposed to BD and HFD. In addition, striatal CX3CL1 levels were increased in all BD- and HFD-exposed groups. Overall, our findings show that adolescent BD and intermittent HFD increase adult alcohol intake and point to neuroinflammation as an important mechanism modulating this interaction.
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13
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Balan I, Aurelian L, Schleicher R, Boero G, O'Buckley T, Morrow AL. Neurosteroid allopregnanolone (3α,5α-THP) inhibits inflammatory signals induced by activated MyD88-dependent toll-like receptors. Transl Psychiatry 2021; 11:145. [PMID: 33637705 PMCID: PMC7909379 DOI: 10.1038/s41398-021-01266-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 01/21/2021] [Accepted: 02/02/2021] [Indexed: 02/08/2023] Open
Abstract
We have shown that endogenous neurosteroids, including pregnenolone and 3α,5α-THP inhibit toll-like receptor 4 (TLR4) signal activation in mouse macrophages and the brain of alcohol-preferring (P) rat, which exhibits innate TLR4 signal activation. The current studies were designed to examine whether other activated TLR signals are similarly inhibited by 3α,5α-THP. We report that 3α,5α-THP inhibits selective agonist-mediated activation of TLR2 and TLR7, but not TLR3 signaling in the RAW246.7 macrophage cell line. The TLR4 and TLR7 signals are innately activated in the amygdala and NAc from P rat brains and inhibited by 3α,5α-THP. The TLR2 and TLR3 signals are not activated in P rat brain and they are not affected by 3α,5α-THP. Co-immunoprecipitation studies indicate that 3α,5α-THP inhibits the binding of MyD88 with TLR4 or TLR7 in P rat brain, but the levels of TLR4 co-precipitating with TRIF are not altered by 3α,5α-THP treatment. Collectively, the data indicate that 3α,5α-THP inhibits MyD88- but not TRIF-dependent TLR signal activation and the production of pro-inflammatory mediators through its ability to block TLR-MyD88 binding. These results have applicability to many conditions involving pro-inflammatory TLR activation of cytokines, chemokines, and interferons and support the use of 3α,5α-THP as a therapeutic for inflammatory disease.
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Affiliation(s)
- Irina Balan
- Department of Psychiatry, Department of Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, 27599, USA
| | - Laure Aurelian
- Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Riana Schleicher
- Department of Psychiatry, Department of Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, 27599, USA
| | - Giorgia Boero
- Department of Psychiatry, Department of Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, 27599, USA
| | - Todd O'Buckley
- Department of Psychiatry, Department of Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, 27599, USA
| | - A Leslie Morrow
- Department of Psychiatry, Department of Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, 27599, USA.
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14
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Harper KM, Knapp DJ, Todd CA, Balan I, Aurelian L, Criswell HE, Breese GR. Phenotyping CCL2 Containing Central Amygdala Neurons Controlling Alcohol Withdrawal-Induced Anxiety. Front Cell Neurosci 2020; 14:580583. [PMID: 33192326 PMCID: PMC7531233 DOI: 10.3389/fncel.2020.580583] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 08/24/2020] [Indexed: 11/30/2022] Open
Abstract
Chemokines such as chemokine (C-C motif) ligand 2 (CCL2) play a role in several behaviors, including anxiety-like behavior, but whether neurons are an important source of CCL2 for behavior and how neuronal CCL2 may work to affect behavior are still debated. When a herpes simplex virus (HSV) vector was used to knockdown CCL2 mRNA in neurons of the central nucleus of the amygdala (CeA) in rats experiencing multiple withdrawals from low dose ethanol, anxiety-like behavior appeared in the social interaction task. To examine this finding further Fractalkine (CX3CL1), a chemokine that is often found to have an opposing function to CCL2 was measured in these rats. Both alcohol withdrawal and CCL2 knockdown increased the levels of the anti-inflammatory protein CX3CL1. The combination of alcohol withdrawal and CCL2 knockdown decreased CX3CL1 and may alter pro-inflammatory/anti-inflammatory balance, and thus highlights the potential importance of CCL2 and CCL2/CX3CL1 balance in anxiety. To find a mechanism by which neuronal chemokines like CCL2 could affect behavior, retrograde tracing with fluorescent nanobeads was done in two brain regions associated with anxiety the bed nucleus of the stria terminalis (BNST) and the ventral periaqueductal gray (VPAG). These studies identified CeA projection neurons to these brain regions that contain CCL2. To demonstrate that CCL2 can be transported via axons to downstream brain regions, the axonal transport blocker, colchicine, was given and 24 h later, the accumulation of CCL2 in CeA neuronal cell bodies was found. Finally, CCL2 in CeA neurons was localized to the synapse using confocal microscopy with enhanced resolution following deconvolution and electron microscopy, which along with the other evidence suggests that CCL2 may be transported down axons in CeA neurons and released from nerve terminals perhaps into brain regions like the BNST and VPAG to affect behaviors such as anxiety. These results suggest that neurons are an important target for chemokine research related to behavior.
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Affiliation(s)
- Kathryn M Harper
- Department of Psychiatry, The University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, United States.,Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, United States
| | - Darin J Knapp
- Department of Psychiatry, The University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, United States.,Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, United States
| | - Caroline A Todd
- Department of Psychiatry, The University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, United States
| | - Irina Balan
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, United States.,Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Laure Aurelian
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD, United States.,Stanford University School of Medicine, Stanford University, Stanford, CA, United States
| | - Hugh E Criswell
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, United States
| | - George R Breese
- Department of Psychiatry, The University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, United States.,Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, United States.,Department of Pharmacology, The University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, United States
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15
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Vena AA, Zandy SL, Cofresí RU, Gonzales RA. Behavioral, neurobiological, and neurochemical mechanisms of ethanol self-administration: A translational review. Pharmacol Ther 2020; 212:107573. [PMID: 32437827 PMCID: PMC7580704 DOI: 10.1016/j.pharmthera.2020.107573] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/29/2020] [Indexed: 12/16/2022]
Abstract
Alcohol use disorder has multiple characteristics including excessive ethanol consumption, impaired control over drinking behaviors, craving and withdrawal symptoms, compulsive seeking behaviors, and is considered a chronic condition. Relapse is common. Determining the neurobiological targets of ethanol and the adaptations induced by chronic ethanol exposure is critical to understanding the clinical manifestation of alcohol use disorders, the mechanisms underlying the various features of the disorder, and for informing medication development. In the present review, we discuss ethanol's interactions with a variety of neurotransmitter systems, summarizing findings from preclinical and translational studies to highlight recent progress in the field. We then describe animal models of ethanol self-administration, emphasizing the value, limitations, and validity of commonly used models. Lastly, we summarize the behavioral changes induced by chronic ethanol self-administration, with an emphasis on cue-elicited behavior, the role of ethanol-related memories, and the emergence of habitual ethanol seeking behavior.
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Affiliation(s)
- Ashley A Vena
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, United States of America
| | | | - Roberto U Cofresí
- Psychological Sciences, University of Missouri, United States of America
| | - Rueben A Gonzales
- Division of Pharmacology and Toxicology, College of Pharmacy and Institute for Neuroscience, The University of Texas at Austin, United States of America.
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16
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Morrow AL, Boero G, Porcu P. A Rationale for Allopregnanolone Treatment of Alcohol Use Disorders: Basic and Clinical Studies. Alcohol Clin Exp Res 2020; 44:320-339. [PMID: 31782169 PMCID: PMC7018555 DOI: 10.1111/acer.14253] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 11/19/2019] [Indexed: 12/17/2022]
Abstract
For many years, research from around the world has suggested that the neuroactive steroid (3α,5α)-3-hydroxypregnan-20-one (allopregnanolone or 3α,5α-THP) may have therapeutic potential for treatment of various symptoms of alcohol use disorders (AUDs). In this critical review, we systematically address all the evidence that supports such a suggestion, delineate the etiologies of AUDs that are addressed by treatment with allopregnanolone or its precursor pregnenolone, and the rationale for treatment of various components of the disease based on basic science and clinical evidence. This review presents a theoretical framework for understanding how endogenous steroids that regulate the effects of stress, alcohol, and the innate immune system could play a key role in both the prevention and the treatment of AUDs. We further discuss cautions and limitations of allopregnanolone or pregnenolone therapy with suggestions regarding the management of risk and the potential for helping millions who suffer from AUDs.
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Affiliation(s)
- A. Leslie Morrow
- Department of Psychiatry, Department of Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC 27599
| | - Giorgia Boero
- Department of Psychiatry, Department of Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC 27599
| | - Patrizia Porcu
- Neuroscience Institute, National Research Council of Italy (CNR), Cagliari, Italy
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