Ferroptosis is an iron- and lipotoxicity-dependent form of regulated cell death (RCD). It is morphologically and biochemically distinct from characteristics of other cell death. This modality has been intensively investigated in recent years due to its involvement in a wide array of pathologies, including cancer, neurodegenerative diseases, and acute kidney injury. Dysregulation of ferroptosis has also been linked to various liver diseases and its modification may provide a hopeful and attractive therapeutic concept. Indeed, targeting ferroptosis may prevent the pathophysiological progression of several liver diseases, such as hemochromatosis, nonalcoholic steatohepatitis, and ethanol-induced liver injury. On the contrary, enhancing ferroptosis may promote sorafenib-induced ferroptosis and pave the way for combination therapy in hepatocellular carcinoma. Glutathione peroxidase 4 (GPx4) and system x_c ⁻ have been identified as key players to mediate ferroptosis pathway. More recently diverse signaling pathways have also been observed. The connection between ferroptosis and other forms of RCD is intricate and compelling, where discoveries in this field advance our understanding of cell survival and fate. In this review, we summarize the central molecular machinery of ferroptosis, describe the role of ferroptosis in non-cancer hepatic disease conditions and discuss the potential to manipulate ferroptosis as a therapeutic strategy.

Hepatocellular death is a sensitive parameter for detecting acute liver injury (ALI) of toxic, viral, metabolic, and autoimmune origin. Ferroptosis has recently been implicated in carbon tetrachloride (CCl₄)-induced ALI. However, the underpinning mechanism and mechanistic basis remain elusive. In this study, bicyclol, a proprietary hepatoprotectant in China, and ferroptosis-specific inhibitor ferrostatin-1 (Fer-1) were administered in CCl₄-injured mice. A panel of ferroptosis-related markers, including mitochondria morphology, reactive oxygen species production, protein adducts in response to lipid peroxidation, and key modulators of ferroptotic process, was determined in vivo. Erastin-treated L-O2 hepatocytes were transfected with glutathione peroxidase 4 (GPx4) or nuclear factor erythroid 2-related factor 2 (Nrf2) siRNA to delineate the pathway of bicyclol against ferroptosis in vitro. As a result, CCl₄ led to iron accumulation, excessive reactive oxygen species production, enhanced lipid peroxidation, and characteristic morphological changes in mitochondria, along with a decrease in GPx4 and xCT protein levels in ALI mice liver, all of which were generally observed in ferroptosis. The use of Fer-1 further corroborated that ferroptosis is responsible for liver damage. Bicyclol exerted its hepatoprotection by preventing the aforesaid ferroptotic process. Furthermore, bicyclol alleviated erastin-induced cellular inviability, destruction, and lipid peroxidation in vitro. Knockdown of GPx4 diminished these protective activities against perturbations associated with ferroptosis in L-O2 hepatocytes. Additionally, Nrf2 silencing drastically reduced GPx4 levels, and further impeded the medicinal effects of bicyclol. In summary, positively regulating Nrf2-GPx4 axis by bicyclol can prevent ferroptosis in CCl₄-induced ALI in mice.

Regenerating gene (REG) family proteins serve as multifunctional secretory molecules with trophic, antiapoptotic, anti-inflammatory, antimicrobial and probably immuno-regulatory effects. Since their discovery, accumulating evidence has clarified the potential roles of the REG family in the occurrence, progression and development of a wide range of inflammatory and inflammation-associated diseases of the gastrointestinal (GI) tract. However, significant gaps still exist due to the undefined nature of certain receptors, regulatory signaling pathways and possible interactions among distinct Reg members. In this narrative review, we first describe the structural features, distribution pattern and purported regulatory mechanisms of REG family proteins. Furthermore, we summarize the established and proposed roles of REG proteins in the pathogenesis of various inflammation-associated pathologies of the GI tract and the body as a whole, focusing particularly on carcinogenesis in the ulcerative colitis—colitic cancer sequence and gastric cancer. Finally, the clinical relevance of REG products in the context of diagnosis, treatment and prognostication are also discussed in detail. The current evidence suggests a need to better understanding the versatile roles of Reg family proteins in the pathogenesis of inflammatory-associated diseases, and their broadened future usage as therapeutic targets and prognostic biomarkers is anticipated.