The biosynthesis and maturation of proteins are primarily regulated by the endoplasmic reticulum in its physiological state. Thus, the disruption of physiological homeostasis initiates the buildup of unfolded and misfolded proteins in the endoplasmic reticulum, resulting in endoplasmic reticulum stress (ERS) and unfolded protein response (UPR). One of the important pathways by which UPR maintains intracellular homeostasis under ERS is activating protein kinase R-like endoplasmic reticulum kinase (PERK). The activation of the PERK pathway stimulates eukaryotic translation initiation factor 2 subunit-α (eIF2α) phosphorylation and the selective translation of active transcription factor 4 (ATF4), and PERK induces cell apoptosis by directly binding to the promoter of pro-apoptotic transcription factor C/EBP homologous protein (CHOP). This signaling pathway is also one of the important mechanisms by which UPR participates in the regulation of hematological malignancies and immune cells in a tumor microenvironment. This article provides an overview of advancements in research into the PERK-eIF2α-ATF4-CHOP signaling pathway in hematological malignancies and the potential therapeutic benefits of targeting this signaling pathway.

Objective To investigate whether quercetin inhibits pyroptosis of mouse fibroblast NIH-3T3 cells by regulating the NLRP3/caspase-1/GSDMD signaling pathway.Methods NIH-3T3 cells were treated with quercetin or MCC950(a specific inhibitor of NLRP3)before stimulation with lipopolysaccharide(LPS)and ATP to induce cell pyroptosis.The optimal quercetin concentration and duration were screened using the CCK-8assay after testing various concentrations and times.Morphological changes of the treated cells was observed,and the levels of IL-18 and IL-1β in the cell culture supernatant were detected with ELISA;the protein expressions of NLRP3,cleaved caspase-1,and GSDMD-N and the mRNA levels of NLRP3,caspase-1 and GSDMD were detected using Western blotting and qRT-PCR.The changes in cell pyroptosis were examined with TUNEL staining and LDH release assay.Results The CCK-8 assay indicated that 24-hour treatment with 20 μmol/L quercetin yielded the most favorable results.LPS and ATP stimulation of NIH-3T3 cells induced obvious swelling,cell membrane rupture and leakage of cell contents,significantly increased IL-18 and IL-1β levels,and enhanced protein expressions of NLRP3,cleaved caspase-1 and GSDMD-N and mRNA levels of NLRP3,caspase-1 and GSDMD.LPS and ATP stimulation also caused a significant increment of TUNEL-positive cell counts and LDH release in NIH-3T3 cells.Treatment with quercetin or MCC950 significantly reduced cell pyroptosis induced by LPS and ATP,lowered the concentrations of IL-18 and IL-1β,decreased the expression levels of NLRP3,caspase-1/cleaved caspase-1,GSDMD/GSDMD-N,and reduced the number of TUNEL-positive cells and LDH release.Conclusion Quercetin suppresses pyroptosis of mouse fibroblasts stimulated with LPS and ATP and reduces secretion of inflammatory cytokines by inhibiting the NLRP3/caspase-1/GSDMD pathway.

Objective To investigate whether quercetin inhibits pyroptosis of mouse fibroblast NIH-3T3 cells by regulating the NLRP3/caspase-1/GSDMD signaling pathway.Methods NIH-3T3 cells were treated with quercetin or MCC950(a specific inhibitor of NLRP3)before stimulation with lipopolysaccharide(LPS)and ATP to induce cell pyroptosis.The optimal quercetin concentration and duration were screened using the CCK-8assay after testing various concentrations and times.Morphological changes of the treated cells was observed,and the levels of IL-18 and IL-1β in the cell culture supernatant were detected with ELISA;the protein expressions of NLRP3,cleaved caspase-1,and GSDMD-N and the mRNA levels of NLRP3,caspase-1 and GSDMD were detected using Western blotting and qRT-PCR.The changes in cell pyroptosis were examined with TUNEL staining and LDH release assay.Results The CCK-8 assay indicated that 24-hour treatment with 20 μmol/L quercetin yielded the most favorable results.LPS and ATP stimulation of NIH-3T3 cells induced obvious swelling,cell membrane rupture and leakage of cell contents,significantly increased IL-18 and IL-1β levels,and enhanced protein expressions of NLRP3,cleaved caspase-1 and GSDMD-N and mRNA levels of NLRP3,caspase-1 and GSDMD.LPS and ATP stimulation also caused a significant increment of TUNEL-positive cell counts and LDH release in NIH-3T3 cells.Treatment with quercetin or MCC950 significantly reduced cell pyroptosis induced by LPS and ATP,lowered the concentrations of IL-18 and IL-1β,decreased the expression levels of NLRP3,caspase-1/cleaved caspase-1,GSDMD/GSDMD-N,and reduced the number of TUNEL-positive cells and LDH release.Conclusion Quercetin suppresses pyroptosis of mouse fibroblasts stimulated with LPS and ATP and reduces secretion of inflammatory cytokines by inhibiting the NLRP3/caspase-1/GSDMD pathway.