Podocytes are specialized epithelial cells that play a significant role in maintaining the integrity of the glomerular filtration barrier and preventing urinary protein leakage. We investigated the contribution of protein tyrosine phosphatase Shp2 to lipopolysaccharide (LPS)-induced renal injury. We report increased Shp2 expression in murine kidneys and cultured podocytes following an LPS challenge. To determine the role of podocyte Shp2in vivo, we generated podocyte-specific Shp2 knockout (pod-Shp2 KO) mice. Following administration of LPS, pod-Shp2 KO mice exhibited lower proteinuria and blood urea nitrogen concentrations than controls indicative of preserved filter integrity. In addition, renal mRNA and serum concentrations of inflammatory cytokines IL-1β, TNFα, INFγ and IL-12 p70 were significantly decreased in LPS-treated knockout mice compared with controls. Moreover, the protective effects of podocyte Shp2 deficiency were associated with decreased LPS-induced NF-κB and MAPK activation, nephrin phosphorylation and attenuated endoplasmic reticulum stress. These effects were recapitulated in differentiated E11 murine podocytes with lentiviral-mediated Shp2 knockdown. Furthermore, Shp2 deficient podocytes displayed reduced LPS-induced migration in a wound healing assay. These findings identify Shp2 in podocytes as a significant contributor to the signaling events following LPS challenge and suggest that inhibition of Shp2 in podocytes may present a potential therapeutic target for podocytopathies.

Alcoholic liver disease (ALD) is a major health problem and a significant cause of liver-related death. Currently, the mainstay for ALD therapy is alcohol abstinence highlighting the need to develop pharmacotherapeutic approaches. Protein-tyrosine phosphatase 1B (PTP1B) is an established regulator of hepatic functions, but its role in ALD is mostly unexplored. In this study, we used mice with liver-specific PTP1B disruption as well as pharmacological inhibition to investigate the in vivo function of this phosphatase in ALD. We report upregulation of hepatic PTP1B in the chronic plus binge mouse model and, importantly, in liver biopsies of alcoholic hepatitis patients. Also, mice with hepatic PTP1B disruption attenuated ethanol-induced injury, inflammation, and steatosis compared with ethanol-fed control animals. Moreover, PTP1B deficiency was associated with decreased ethanol-induced oxidative stress in vivo and ex vivo. Further, pharmacological modulation of oxidative balance in hepatocytes identified diminished oxidative stress as a contributor to the salutary effects of PTP1B deficiency. Notably, PTP1B pharmacological inhibition elicited beneficial effects and mitigated hepatic injury, inflammation, and steatosis caused by ethanol feeding. In summary, these findings causally link hepatic PTP1B and ALD and define a potential therapeutic target for the management of this disease.

Alcohol-associated liver disease (ALD) is a significant cause of liver-related morbidity and mortality worldwide and with limited therapies. Soluble epoxide hydrolase (sEH; Ephx2) is a largely cytosolic enzyme that is highly expressed in the liver and is implicated in hepatic function, but its role in ALD has heretofore remained uncharted. To decipher the role of hepatic sEH in ALD, we generated mice with liver-specific sEH disruption (Alb-Cre; Ephx2fl/fl). Alb-Cre; Ephx2fl/fl and control (Ephx2fl/fl) mice were subjected to an ethanol challenge using the chronic plus binge model of ALD and hepatic injury, inflammation, and steatosis evaluated under pair- and ethanol-fed states. Additionally, we investigated the capacity of pharmacological inhibition of sEH in the chronic plus binge mouse model. We observed elevation of hepatic sEH in mice upon ethanol consumption, suggesting that dysregulated hepatic sEH expression might be involved in ALD. Alb-Cre; Ephx2fl/fl mice presented efficient deletion of hepatic sEH with the corresponding attenuation in the sEH activity and alteration in the lipid epoxide/diol ratio. Consistently, hepatic sEH deficiency ameliorated ethanol-induced hepatic injury, inflammation, and steatosis. Additionally, targeted metabolomics identified lipid mediators that were significantly impacted by hepatic sEH deficiency. Moreover, hepatic sEH deficiency was associated with a significant attenuation of ethanol-induced hepatic endoplasmic reticulum and oxidative stress. Notably, pharmacological inhibition of sEH recapitulated the effects of hepatic sEH deficiency and abrogated injury, inflammation, and steatosis caused by ethanol feeding. These findings elucidated a role for sEH in ALD and validated a pharmacological inhibitor of this enzyme in a preclinical mouse model as a potential therapeutic approach.

Alcohol-associated hepatitis (AH) is a form of acute-on-chronic liver failure characterized by intrahepatic neutrophilic inflammation. In hepatocytes, IL-6 signals through either membrane-bound (classical signaling) or soluble (trans-signaling; TS) IL-6 receptors (IL-6Rs) to regulate liver injury responses. This study investigated the role of IL-6TS in the pathophysiology of AH. RNA sequencing of liver biopsies from patients with alcohol-related liver disease demonstrated a progressive decline in IL-6R expression correlating with increasing AH severity. Transforming growth factor (TGF)-β1 emerged as the most potent negative regulator of IL-6R expression. Notably, STAT3-dependent gene expression was increased in severe AH. In vitro, treatment of HepG2 cells with TGF-β1 suppressed IL-6R expression. Subsequent treatment with either IL-6 to stimulate classical signaling, or hyper-IL-6, a recombinant IL-6/IL-6R α peptide, to activate trans-signaling activated STAT3. Hyper-IL-6, but not IL-6, restored STAT3 activation in the face of suppressed IL-6R. RNA sequencing of hyper-IL-6 stimulated cells identified a gene signature that stratified a subset of AH patients with: i) enhanced IL-6TS activity, ii) increased intrahepatic neutrophilic infiltration, and iii) transcriptional enrichment of leukocyte migration pathways. Female mice treated with 10-day chronic-plus-binge ethanol exhibited enhanced STAT3 activation despite reduced hepatic IL-6R expression, leading to increased expression of neutrophilic activators, with colocalization of Ly6G⁺ leukocytes and STAT3⁺ hepatocytes. Collectively, these results indicate that IL-6TS preserves hepatocyte STAT3-dependent gene expression and promotes neutrophilic inflammation in AH.