Studies in both humans and animal models demonstrated that chronic alcohol/e-cigarette (e-Cig) exposure affects mitochondrial function and impairs barrier function in brain microvascular endothelial cells (BMVECs). Identification of the signaling pathways by which chronic alcohol/e-Cig exposure induces mitochondrial damage in BMVEC is vital for protection of the blood–brain barrier (BBB). To address the issue, we treated human BMVEC [hBMVECs (D3 cell-line)] with ethanol (ETH) [100 mM], acetaldehyde (ALD) [100 μM], or e-cigarette (e-Cig) [35 ng/mL of 1.8% or 0% nicotine] conditioned medium and showed reduced mitochondrial oxidative phosphorylation (OXPHOS) measured by a Seahorse analyzer. Seahorse data were further complemented with the expression of mitochondrial OXPHOS proteins detected by Western blots. We also observed cytosolic escape of ATP and its extracellular release due to the disruption of mitochondrial membrane potential caused by ETH, ALD, or 1.8% e-Cig exposure. Moreover ETH, ALD, or 1.8% e-Cig treatment resulted in elevated purinergic P2X7r and TRPV1 channel gene expression, measured using qPCR. We also demonstrated the protective role of P2X7r antagonist A804598 (10 μM) in restoring mitochondrial oxidative phosphorylation levels and preventing extracellular ATP release. In a BBB functional assay using trans-endothelial electrical resistance, we showed that blocking the P2X7r channel enhanced barrier function. In summary, we identified the potential common pathways of mitochondrial injury caused by ETH, ALD, and 1.8% e-Cig which allow new protective interventions. We are further investigating the potential link between P2X7 regulatory pathways and mitochondrial health.

Excessive production and response to Type I interferons (IFNs) is a hallmark of systemic lupus erythematosus (SLE). Neuropsychiatric lupus (NPSLE) is a common manifestation of human SLE, with major depression as the most common presentation. Clinical studies have demonstrated that IFNα can cause depressive symptoms. We have shown that the kallikrein–kinin system (KKS) [comprised of kallikreins (Klks) and bradykinins] and angiotensin-converting enzyme inhibitors suppressed Type I IFN responses in dendritic cells from lupus-prone mice and human peripheral blood mononuclear cells. Tissue Klk genes are decreased in patients with lupus, and giving exogenous Klk1 ameliorated kidney pathology in mice. We retro-orbitally administered mouse klk1 gene-carrying adenovirus in the Murphy Roths Large lymphoproliferative (MRL/lpr) lupus-prone mice at early disease onset and analyzed immune responses and depressive-like behavior. Klk1 improved depressive-like behavior, suppressed interferon-responsive genes and neuroinflammation, and reduced plasma IFNα levels and proinflammatory cytokines. Klk1 also reduced IFNAR1 and JAK1 protein expression, important upstream molecules in Type I IFN signaling. Klk1 reduced bradykinin B1 receptor expression, which is known to induce proinflammatory response. Together, these findings suggest that Klk1 may be a potential therapeutic candidate to control IFNα production/responses and other inflammatory responses in SLE and NPSLE.

Chronic alcohol exposure disrupts blood-brain barrier (BBB) integrity and promotes neuroinflammation, with P2X7 receptor (P2X7R) signaling playing a critical role. Our prior work in male mice linked P2X7R inhibition to reduced extracellular ATP (eATP) release, modulated extracellular vesicle (EV) cargo, and attenuated neuroinflammation in chronic intermittent ethanol (CIE)-exposed mice. However, sex specific roles of P2X7R signaling and EV-mediated mechanisms in alcohol-induced neuroinflammation remain unclear. Male and female mice were exposed to ethanol vapor for three weeks and treated with Brilliant Blue G (BBG), a P2X7R inhibitor. Compared to their respective CIE-unexposed controls, brain gene expression of Tnf-α, Il-1β, Il-6, Mcp-1, and Fasl sig-nificantly increased in CIE-exposed males, while only Il-1β increased in females. P2X7R inhibition significantly reduced these cytokines. Pericyte immunostaining was decreased by CIE (indicating BBB injury) in male mice only and restored by P2X7R inhibition with no difference between groups in females. Occludin staining (another BBB marker) did not differ between the treatment groups in male and female animals. Circulating cytokines (MIP-1α, TNF-α, IL-1β, and IL-27p28/IL-30) were significantly elevated in CIE-exposed males but not in females, with BBG treatment reducing cytokines in males. Circulating eATP, P2X7R, P-glycoprotein, EVs, and EV-mt-DNA that we identified in our previous study were increased in both sexes and partially decreased by P2X7R blockade. Spatial memory was impaired by CIE exposure in males but not females, and this deficit was reversed by BBG treatment. Our findings reveal sex differences in CIE-induced circu-lating cytokines, neuroinflammation, and memory impairment, with a stronger response in males. However, other markers of cell injury associated with CIE exposure were up-regulated in both sexes; P2X7R inhibition effectively mitigated these effects, highlighting the functional relevance of targeting P2X7R in alcohol-induced injury.

Chronic alcohol exposure disrupts blood–brain barrier (BBB) integrity and promotes neuroinflammation, with P2X7 receptor (P2X7R) signaling playing a critical role. Our prior work in male mice linked P2X7R inhibition to reduced extracellular adenosine triphosphate (eATP) release, modulated extracellular vesicle (EV) cargo, and attenuated neuroinflammation in chronic intermittent ethanol (CIE)-exposed mice. However, sex-specific roles of P2X7R signaling and EV-mediated mechanisms in alcohol-induced neuroinflammation remain unclear. Male and female mice were exposed to ethanol vapor for three weeks and treated with Brilliant Blue G (BBG), a P2X7R inhibitor. Compared to their respective CIE-unexposed controls, brain gene expression of tumor necrosis factor–α (Tnf-α), interleukin-1 beta (Il-1b), interleukin-6 (Il-6), monocyte chemoattractant protein-1 (Mcp-1), and Fas ligand (Fasl) significantly increased in CIE-exposed males, while only Il-1b increased in females. P2X7R inhibition significantly reduced these cytokines. Pericyte immunostaining was decreased by CIE (indicating BBB injury) in male mice only and was restored by P2X7R inhibition with no difference between groups in females. Occludin staining (another BBB marker) did not differ between the treatment groups in male and female animals. Circulating cytokines (Macrophage inflammatory protein-1 alpha (MIP-1α), tumor necrosis factor–α (TNF-α), interleukin-1 beta (IL-1β), and interleukin-27 subunit p28/interleukin-30 (IL-27p28/IL-30) were significantly elevated in CIE-exposed males but not in females, with BBG treatment reducing cytokines in males. Circulating eATP, P2X7Rs, P-glycoprotein (P-gp), EVs, and EV-mtDNA, which we identified in our previous study, were increased in both sexes and partially decreased by P2X7R blockade. Spatial memory was impaired by CIE exposure in males but not females, and this deficit was reversed by BBG treatment. Our findings reveal sex differences in CIE-induced circulating cytokines, neuroinflammation, and memory impairment, with a stronger response in males. However, other markers of cell injury associated with CIE exposure were upregulated in both sexes; P2X7R inhibition effectively mitigated these effects, highlighting the functional relevance of targeting the P2X7R in alcohol-induced injury.

Chronic alcohol and nicotine exposure can increase susceptibility to lung injury and promote the release of extracellular ATP (eATP). Elevated eATP activates the purinergic P2X7 receptor (P2X7R), a membrane ion channel that amplifies inflammatory signaling and promotes extracellular vesicle (EV) release. These EVs may serve as mediators of lung to systemic communications. Proteomic analysis of lung epithelial cell-derived EVs revealed enrichment of urokinase-type plasminogen activator (uPA), a key enzyme involved in extracellular matrix remodeling. Treatment of hPAEpiCs with ETH, acetaldehyde (ALD), and e-cigarette vapor, with or without nicotine, induced NLRP3 inflammasome activation, IL-1β secretion, and increased incorporation of uPA into EVs. Exposure of human brain microvascular endothelial cells (hBMVECs) to these EVs enhanced plasmin conversion and activated MMP-9 and TGF-β1, resulting in reduced transendothelial electrical resistance (TEER), indicating blood–brain barrier (BBB) dysfunction. Pharmacological inhibition of P2X7R using ‘A804598’ significantly reduced EV-associated uPA release and attenuated endothelial injury. In vivo, chronic ETH vapor exposure increased expression of uPA, uPAR, MMP-2, and MMP-9 while decreasing SERPIN1 and TIMP1 in murine brain microvessels, changes associated with BBB disruption and IgG leakage into brain parenchyma. P2X7R inhibition normalized these effects. Collectively, these findings identify EV-associated uPA as a mediator of lung-to-brain signaling and BBB injury following ETH and e-cigarette exposure.

Chronic exposure to ethanol (ETH) and e-cigarette vapor activates the P2X7 receptor (P2X7R) in human pulmonary alveolar epithelial cells (hPAEpiCs), promoting extracellular vesicle (EV) release. Proteomic analysis of this EVs identified enrichment of urokinase-type plasminogen activator (uPA), a key extracellular matrix remodeling enzyme. Treatment of hPAEpiCs with ETH, acetaldehyde (ALD), and e-cigarette vapor, with or without nicotine, induced NLRP3 inflammasome activation, IL-1β secretion, and increased incorporation of uPA into EVs. Exposure of human brain microvascular endothelial cells (hBMVECs) to this EVs enhanced plasmin conversion, activated MMP-9 and TGF-β1, resulting in reduced transendothelial electrical resistance (TEER), indicating blood-brain barrier (BBB) dysfunction. Pharmacological inhibition of P2X7R using ‘A804598’ significantly reduced EV-associated uPA release and attenuated endothelial injury. In vivo, chronic ETH vapor exposure increased expression of uPA, uPAR, MMP-2, and MMP-9 while decreasing SERPIN1 and TIMP1 in murine brain microvessels, changes associated with BBB disruption and IgG leakage into brain parenchyma. P2X7R inhibition normalized these effects. Collectively, these findings identify EV-associated uPA as a mediator of lung-to-brain signaling and BBB injury following ETH and e-cigarette exposure.