Inflammatory bowel disease(IBD)is a chronic relapsing gastrointestinal disorder,while the treatment effect is not satisfactory.Immune responsive gene 1(IRG1)is a highly ex-pressed gene in macrophage in response to inf...Inflammatory bowel disease(IBD)is a chronic relapsing gastrointestinal disorder,while the treatment effect is not satisfactory.Immune responsive gene 1(IRG1)is a highly ex-pressed gene in macrophage in response to inflammatory response and catalyzes the production of itaconate.Studies have reported that IRG1/itaconate has a significant antioxidant effect.This study aimed to investigate the effect and mechanism of IRG1/itaconate on dextran sulfate so-dium(DSS)-induced colitis in vivo and in vitro.In vivo experiments,we found IRG1/itaconate ex-erted protective effects against acute colitis by increasing mice weight,the length of colon,reducing disease activity index and colonic inflammation.Meanwhile,IRG1 deletion aggravated the macrophages/CD4+/CD8+T-cell accumulation,and increased the release of interleukin(IL)-1b,tumor necrosis factor-a(TNF-a),IL-6,the activation of nuclear factor-kB(NF-kB)/mitogen-activated protein kinase(MAPK)signaling pathway,and gasdermin D(GSDMD)mediated pyrop-tosis.Four-octyl itaconate(4-OI),a derivative of itaconate,attenuated these changes,therefore relieved DSS-induced colitis.In vitro experiment,we found 4-OI inhibited the reactive oxygen species production,thereby inhibiting the activation of MAPK/NF-kB signaling pathway in RAW264.7 and murine bone-marrow-derived macrophages.Simultaneously,we found 4-OI inhib-ited caspase1/GSDMD-mediated pyroptosis to reduce the release of cytokines.Finally,we found anti-TNF-a agent reduced the severity of DSS-induced colitis and inhibited gasdermin E(GSDME)-mediated pyroptosis in vivo.Meanwhile,our study revealed that 4-OI inhibited caspase3/GSDME-mediated pyroptosis induced by TNF-a in vitro.Taken together,IRG1/itaconate exerted a pro-tective role in DSS-induced colitis by inhibiting inflammatory response and GSDMD/GSDME-medi-ated pyroptosis,which could be a promising candidate for IBD therapy.展开更多
Background:Cisplatin triggers Gasdermin E(GSDME)cleavage,causing membrane bubble formation,content release,and inflammation.Caspase-3 activation initiates GSDME cleavage,and thus inhibiting this pathway mitigates cisp...Background:Cisplatin triggers Gasdermin E(GSDME)cleavage,causing membrane bubble formation,content release,and inflammation.Caspase-3 activation initiates GSDME cleavage,and thus inhibiting this pathway mitigates cisplatin-induced pyroptosis in hepatocytes.This study aimed to delve into how cisplatin induces liver injury via pyroptosis.Methods:For animal experiments,C57BL/6J mice were divided into three groups:control,liver injury model group,and Ac-DMLD-CMK(caspase-3 inhibitor)intervention group.The liver histology was evaluated by hematoxylin and eosin staining,immunohistochemistry,immunofluorescence and TUNEL staining.The mRNA and protein levels were detected by real-time polymerase chain reaction(PCR)and Western blot analysis.For in vitro experiments,HL-7702 cells were treated with cisplatin or GSDME siRNA.Cell pyroptosis was determined via cellular morphology,cytotoxicity and viability detection,flow cytometric assay,and Western blot detection for the expression of pyroptosis-related proteins.Results:Cisplatin-induced distinct liver morphological changes,hepatocellular injury,and inflammation in mice,along with elevated serum alanine aminotransferase(ALT)and aspartate aminotransferase(AST)levels and increased pro-inflammatory cytokine expression.Heightened macrophage infiltration and hepatocellular death indicated cisplatin-induced hepatotoxicity.Cisplatin upregulated GSDME activation,along with Bax-mediated caspase-3 cleavage both in vivo and in vitro,implicating caspase-3/GSDME-dependent pyroptosis in liver injury.Treatment with Ac-DMLD-CMK ameliorated cisplatin-induced liver injury,reducing hepatocellular lesions,serum ALT and AST levels,cytokine expression,macrophage infiltration,and hepatocyte death.Ac-DMLD-CMK also attenuated GSDME-dependent pyroptosis post-cisplatin induction,as evidenced by decreased GSDME expression,Bax upregulation,and cleaved caspase-3 activation.For HL-7702 cells,GSDME siRNA transfection reduced GSDME expression,attenuated typical signs of cisplatin-induced pyroptosis,partially restored cell viability,and significantly inhibited cytotoxicity and a decrease in the proportion of propidium iodide-positive cells,indicating protection against cisplatininduced hepatocyte pyroptosis.Conclusions:Our study underscores the role of the caspase-3/GSDME signaling pathway in mediating cisplatin-induced hepatotoxicity,particularly in cases of excessive or cumulative cisplatin exposure.These findings suggest that targeting GSDME could represent a promising therapeutic approach to mitigate cisplatin-induced liver damage.展开更多
Microglia,the resident monocyte of the central nervous system,play a crucial role in the response to spinal cord injury.However,the precise mechanism remains unclear.To investigate the molecular mechanisms by which mi...Microglia,the resident monocyte of the central nervous system,play a crucial role in the response to spinal cord injury.However,the precise mechanism remains unclear.To investigate the molecular mechanisms by which microglia regulate the neuroinflammatory response to spinal cord injury,we performed single-cell RNA sequencing dataset analysis,focusing on changes in microglial subpopulations.We found that the MG1 subpopulation emerged in the acute/subacute phase of spinal cord injury and expressed genes related to cell pyroptosis,sphingomyelin metabolism,and neuroinflammation at high levels.Subsequently,we established a mouse model of contusive injury and performed intrathecal injection of siRNA and molecular inhibitors to validate the role of ceramide synthase 5 in the neuroinflammatory responses and pyroptosis after spinal cord injury.Finally,we established a PC12-BV2 cell co-culture system and found that ceramide synthase 5 and pyroptosis-associated proteins were highly expressed to induce the apoptosis of neuron cells.Inhibiting ceramide synthase 5 expression in a mouse model of spinal cord injury effectively reduced pyroptosis.Furthermore,ceramide synthase 5-induced pyroptosis was dependent on activation of the NLRP3 signaling pathway.Inhibiting ceramide synthase 5 expression in microglia in vivo reduced neuronal apoptosis and promoted recovery of neurological function.Pla2g7 formed a“bridge”between sphingolipid metabolism and ceramide synthase 5-mediated cell death by inhibiting the NLRP3 signaling pathway.Collectively,these findings suggest that inhibiting ceramide synthase 5 expression in microglia after spinal cord injury effectively suppressed microglial pyroptosis mediated by NLRP3,thereby exerting neuroprotective effects.展开更多
基金supported by the National Natural Science Foundation of China(No.81701883,82072736,82172171)。
文摘Inflammatory bowel disease(IBD)is a chronic relapsing gastrointestinal disorder,while the treatment effect is not satisfactory.Immune responsive gene 1(IRG1)is a highly ex-pressed gene in macrophage in response to inflammatory response and catalyzes the production of itaconate.Studies have reported that IRG1/itaconate has a significant antioxidant effect.This study aimed to investigate the effect and mechanism of IRG1/itaconate on dextran sulfate so-dium(DSS)-induced colitis in vivo and in vitro.In vivo experiments,we found IRG1/itaconate ex-erted protective effects against acute colitis by increasing mice weight,the length of colon,reducing disease activity index and colonic inflammation.Meanwhile,IRG1 deletion aggravated the macrophages/CD4+/CD8+T-cell accumulation,and increased the release of interleukin(IL)-1b,tumor necrosis factor-a(TNF-a),IL-6,the activation of nuclear factor-kB(NF-kB)/mitogen-activated protein kinase(MAPK)signaling pathway,and gasdermin D(GSDMD)mediated pyrop-tosis.Four-octyl itaconate(4-OI),a derivative of itaconate,attenuated these changes,therefore relieved DSS-induced colitis.In vitro experiment,we found 4-OI inhibited the reactive oxygen species production,thereby inhibiting the activation of MAPK/NF-kB signaling pathway in RAW264.7 and murine bone-marrow-derived macrophages.Simultaneously,we found 4-OI inhib-ited caspase1/GSDMD-mediated pyroptosis to reduce the release of cytokines.Finally,we found anti-TNF-a agent reduced the severity of DSS-induced colitis and inhibited gasdermin E(GSDME)-mediated pyroptosis in vivo.Meanwhile,our study revealed that 4-OI inhibited caspase3/GSDME-mediated pyroptosis induced by TNF-a in vitro.Taken together,IRG1/itaconate exerted a pro-tective role in DSS-induced colitis by inhibiting inflammatory response and GSDMD/GSDME-medi-ated pyroptosis,which could be a promising candidate for IBD therapy.
基金supported by grants from the National Natural Science Foundation of China(8170060495 and 82170682)。
文摘Background:Cisplatin triggers Gasdermin E(GSDME)cleavage,causing membrane bubble formation,content release,and inflammation.Caspase-3 activation initiates GSDME cleavage,and thus inhibiting this pathway mitigates cisplatin-induced pyroptosis in hepatocytes.This study aimed to delve into how cisplatin induces liver injury via pyroptosis.Methods:For animal experiments,C57BL/6J mice were divided into three groups:control,liver injury model group,and Ac-DMLD-CMK(caspase-3 inhibitor)intervention group.The liver histology was evaluated by hematoxylin and eosin staining,immunohistochemistry,immunofluorescence and TUNEL staining.The mRNA and protein levels were detected by real-time polymerase chain reaction(PCR)and Western blot analysis.For in vitro experiments,HL-7702 cells were treated with cisplatin or GSDME siRNA.Cell pyroptosis was determined via cellular morphology,cytotoxicity and viability detection,flow cytometric assay,and Western blot detection for the expression of pyroptosis-related proteins.Results:Cisplatin-induced distinct liver morphological changes,hepatocellular injury,and inflammation in mice,along with elevated serum alanine aminotransferase(ALT)and aspartate aminotransferase(AST)levels and increased pro-inflammatory cytokine expression.Heightened macrophage infiltration and hepatocellular death indicated cisplatin-induced hepatotoxicity.Cisplatin upregulated GSDME activation,along with Bax-mediated caspase-3 cleavage both in vivo and in vitro,implicating caspase-3/GSDME-dependent pyroptosis in liver injury.Treatment with Ac-DMLD-CMK ameliorated cisplatin-induced liver injury,reducing hepatocellular lesions,serum ALT and AST levels,cytokine expression,macrophage infiltration,and hepatocyte death.Ac-DMLD-CMK also attenuated GSDME-dependent pyroptosis post-cisplatin induction,as evidenced by decreased GSDME expression,Bax upregulation,and cleaved caspase-3 activation.For HL-7702 cells,GSDME siRNA transfection reduced GSDME expression,attenuated typical signs of cisplatin-induced pyroptosis,partially restored cell viability,and significantly inhibited cytotoxicity and a decrease in the proportion of propidium iodide-positive cells,indicating protection against cisplatininduced hepatocyte pyroptosis.Conclusions:Our study underscores the role of the caspase-3/GSDME signaling pathway in mediating cisplatin-induced hepatotoxicity,particularly in cases of excessive or cumulative cisplatin exposure.These findings suggest that targeting GSDME could represent a promising therapeutic approach to mitigate cisplatin-induced liver damage.
基金supported by grants from the National Key Research and Development Program of China,No.2017YFA0105400(to LR)the Key Research and Development Program of Guangdong Province,No.2019B020236002(to LR)the National Natural Science Foundation of China,Nos.81972111(to LZ),81772349(to BL).
文摘Microglia,the resident monocyte of the central nervous system,play a crucial role in the response to spinal cord injury.However,the precise mechanism remains unclear.To investigate the molecular mechanisms by which microglia regulate the neuroinflammatory response to spinal cord injury,we performed single-cell RNA sequencing dataset analysis,focusing on changes in microglial subpopulations.We found that the MG1 subpopulation emerged in the acute/subacute phase of spinal cord injury and expressed genes related to cell pyroptosis,sphingomyelin metabolism,and neuroinflammation at high levels.Subsequently,we established a mouse model of contusive injury and performed intrathecal injection of siRNA and molecular inhibitors to validate the role of ceramide synthase 5 in the neuroinflammatory responses and pyroptosis after spinal cord injury.Finally,we established a PC12-BV2 cell co-culture system and found that ceramide synthase 5 and pyroptosis-associated proteins were highly expressed to induce the apoptosis of neuron cells.Inhibiting ceramide synthase 5 expression in a mouse model of spinal cord injury effectively reduced pyroptosis.Furthermore,ceramide synthase 5-induced pyroptosis was dependent on activation of the NLRP3 signaling pathway.Inhibiting ceramide synthase 5 expression in microglia in vivo reduced neuronal apoptosis and promoted recovery of neurological function.Pla2g7 formed a“bridge”between sphingolipid metabolism and ceramide synthase 5-mediated cell death by inhibiting the NLRP3 signaling pathway.Collectively,these findings suggest that inhibiting ceramide synthase 5 expression in microglia after spinal cord injury effectively suppressed microglial pyroptosis mediated by NLRP3,thereby exerting neuroprotective effects.
