Ferroptosis in organ ischemia-reperfusion injuries: recent advancements and strategies.

Ferroptosis is a newly discovered type of regulated cell death participated in multiple diseases. Different from other classical cell death programs such as necrosis and apoptosis, ferroptosis involving iron-catalyzed lipid peroxidation is characterized by Fe2+ accumulation and mitochondria alterations. The phenomenon of oxidative stress following organ ischemia-reperfusion (I/R) has recently garnered attention for its connection to the onset of ferroptosis and subsequent reperfusion injuries. This article provides a comprehensive overview underlying the mechanisms of ferroptosis, with a further focus on the latest research progress regarding interference with ferroptotic pathways in organ I/R injuries, such as intestine, lung, heart, kidney, liver, and brain. Understanding the links between ferroptosis and I/R injury may inform potential therapeutic strategies and targeted agents.

NLRP3 deficiency protects against acetaminophen­induced liver injury by inhibiting hepatocyte pyroptosis.

Acetaminophen (APAP) overdose is the primary cause of drug­induced acute liver failure in numerous Western countries. NLR family pyrin domain containing 3 (NLRP3) inflammasome activation serves a pivotal role in the pathogenesis of various forms of acute liver injury. However, the cellular source for NLRP3 induction and its involvement during APAP­induced hepatotoxicity have not been thoroughly investigated. In the present study, hematoxylin and eosin staining was performed to assess histopathological changes of liver tissue. Immunohistochemistry staining(NLRP3, Caspase­1, IL­1ß, GSDMD and Caspase­3), western blotting (NLRP3, Caspase­1, IL­1ß, GSDMD and Caspase­3) and RT­qPCR (NLRP3, Caspase­1 and IL­1ß) were performed to assess the expression of NLRP3/GSDMD signaling pathway. TUNEL staining was performed to assess apoptosis of liver tissue. The serum expression levels of inflammatory factors (IL­6, IL­18, IL­1ß and TNF­α) were assessed using ELISA and inflammation of liver tissue was assessed using immunohistochemistry (Ly6G and CD68) and RT­qPCR (TNF­α, Il­6, Mcp­1, Cxcl­1, Cxcl­2). A Cell Counting Kit­8 was performed to assess cell viability and apoptosis. Protein and gene expression were analyzed by western blotting (PCNA, CCND1) and RT­qPCR (CyclinA2, CyclinD1 and CyclinE1). Through investigation of an APAP­induced acute liver injury model (AILI), the present study demonstrated that APAP overdose induced activation of NLRP3 and cleavage of gasdermin D (GSDMD) in hepatocytes, both in vivo and in vitro. Additionally, mice with hepatocyte­specific knockout of Nlrp3 exhibited reduced liver injury and lower mortality following APAP intervention, accompanied by decreased infiltration of inflammatory cells and attenuated inflammatory response. Furthermore, pharmacological blockade of NLRP3/GSDMD signaling using MCC950 or disulfiram significantly ameliorated liver injury and reduced hepatocyte death. Notably, hepatocyte Nlrp3 deficiency promoted liver recovery by enhancing hepatocyte proliferation. Collectively, the present study demonstrated that inhibition of the NLRP3 inflammasome protects against APAP­induced acute liver injury by reducing hepatocyte pyroptosis and suggests that targeting NLRP3 may hold therapeutic potential for treating AILI.

TNF-α/IL-1ß-licensed hADSCs alleviate cholestatic liver injury and fibrosis in mice via COX-2/PGE2 pathway.

BACKGROUND: Adipose tissue-derived stem cell (ADSC) transplantation has been shown to be effective for the management of severe liver disorders. Preactivation of ADSCs enhanced their therapeutic efficacy. However, these effects have not yet been examined in relation to cholestatic liver injury. METHODS: In the present study, a cholestatic liver injury model was established by bile duct ligation (BDL) in male C57BL/6 mice. Human ADSCs (hADSCs) with or without tumor necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1ß) pretreatment were administrated into the mice via tail vein injections. The efficacy of hADSCs on BDL-induced liver injury was assessed by histological staining, real-time quantitative PCR (RT-qPCR), Western blot, and enzyme-linked immune sorbent assay (ELISA). In vitro, the effects of hADSC conditioned medium on the activation of hepatic stellate cells (HSCs) were investigated. Small interfering RNA (siRNA) was used to knock down cyclooxygenase-2 (COX-2) in hADSCs. RESULTS: TNF-α/IL-1ß preconditioning could downregulate immunogenic gene expression and enhance the engraftment efficiency of hADSCs. Compared to control hADSCs (C-hADSCs), TNF-α/IL-1ß-pretreated hADSCs (P-hADSCs) significantly alleviated BDL-induced liver injury, as demonstrated by reduced hepatic cell death, attenuated infiltration of Ly6G + neutrophils, and decreased expression of pro-inflammatory cytokines TNF-α, IL-1ß, C-X-C motif chemokine ligand 1 (CXCL1), and C-X-C motif chemokine ligand 2 (CXCL2). Moreover, P-hADSCs significantly delayed the development of BDL-induced liver fibrosis. In vitro, conditioned medium from P-hADSCs significantly inhibited HSC activation compared to that from C-hADSCs. Mechanistically, TNF-α/IL-1ß upregulated COX-2 expression and increased prostaglandin E2 (PGE2) secretion. The blockage of COX-2 by siRNA transfection reversed the benefits of P-hADSCs for PGE2 production, HSC activation, and liver fibrosis progression. CONCLUSION: In conclusion, our results suggest that TNF-α/IL-1ß pretreatment enhances the efficacy of hADSCs in mice with cholestatic liver injury, partially through the COX-2/PGE2 pathway.

The Role of the NLRP3 Inflammasome and Programmed Cell Death in Acute Liver Injury.

Acute liver injury (ALI) is a globally important public health issue that, when severe, rapidly progresses to acute liver failure, seriously compromising the life safety of patients. The pathogenesis of ALI is defined by massive cell death in the liver, which triggers a cascade of immune responses. Studies have shown that the aberrant activation of the nod-like receptor protein 3 (NLRP3) inflammasome plays an important role in various types of ALI and that the activation of the NLRP3 inflammasome causes various types of programmed cell death (PCD), and these cell death effectors can in turn regulate NLRP3 inflammasome activation. This indicates that NLRP3 inflammasome activation is inextricably linked to PCD. In this review, we summarize the role of NLRP3 inflammasome activation and PCD in various types of ALI (APAP, liver ischemia reperfusion, CCl4, alcohol, Con A, and LPS/D-GalN induced ALI) and analyze the underlying mechanisms to provide references for future relevant studies.