Mesaconic acid has a special chemical structure and can undergo a series of reactions such as polymerization and addition. It is an important chemical intermediate and widely used in material, chemical and other indus...Mesaconic acid has a special chemical structure and can undergo a series of reactions such as polymerization and addition. It is an important chemical intermediate and widely used in material, chemical and other industries. The chemical synthesis of mesaconic acid requires nitric acid, which is dangerous and harmful to the environment. The production of mesaconic acid by microbial fermentation has the characteristics of low raw material price, high efficiency and strong specificity, and thus a strong industrial application prospect. Mesaconic acid is an intermediate product of glutamic acid degradation pathway of microorganisms such as Clostridium tetani. However, at present, few reports have been conducted on the production of mesaconic acid by metabolic engineering microorganisms. In this study, glutamate mutase(GLM) and 3-methylaspartate ammonialyase(MAL) from C. tetani were recombined and expressed in Escherichia coli, and the obtained strain, BL21(DE3)/pETDuet-1-MAL-mutS-mutE, achieved the yield of mesaconic acid of 1.06 g/L. Compared with the wild type, the yields of mesaconic acid from mutants G133A and G133S increased by 21% and 16%, respectively. After 24 h of flask fermentation, the yields of mesaconic acid reached 1.28 and 1.23 g/L, respectively. This study can provide reference for microbial synthesis of mesaconic acid.展开更多
Background and Aims:Autoimmune hepatitis(AIH)is a severe immune-mediated liver disease with limited treatment options beyond immunosuppressants,which carry significant side effects.Existing evidence suggests that mesa...Background and Aims:Autoimmune hepatitis(AIH)is a severe immune-mediated liver disease with limited treatment options beyond immunosuppressants,which carry significant side effects.Existing evidence suggests that mesaconate(MSA)possesses immunomodulatory properties and may offer advantages over itaconate derivatives by avoiding succinate dehydrogenase inhibition.However,its specific role in AIH remains unclear.This study aimed to investigate the therapeutic effects of MSA on AIH and to elucidate its underlying mechanisms of action.Methods:A murine AIH model was established via tail vein injection of concanavalin A(ConA,20mg/kg).MSA(250 mg/kg)was administered intraperitoneally 6 h before ConA exposure.Liver histology,serum transaminase levels,apoptosis markers,oxidative stress markers,and inflammatory cytokines were analyzed to assess the therapeutic efficacy of MSA.Additionally,RNA sequencing and Western blotting were performed to explore the mechanisms of MSA action.In vitro validation was conducted using RAW264.7 macrophages pretreated with MSA(1 mM)followed by interferon-gamma(IFN-Y,50 ng/mL)stimulation.Results:MSA pretreatment effectively mitigated ConA-induced AIH by reducing inflammatory responses,oxidative stress,and apoptosis both in vivo and in vitro.The underlying protective mechanisminvolved MSA-mediated downregulation of IFN-y expression and subsequent inhibition of the Janus tyrosine kinase 1/2-signal transducer and activator of transcription 1 signaling pathway.The involvement of this pathway in human AIH was also confirmed.Conclusions:This study provides the first evidence that MSA ameliorates AIH by suppressing the IFN-y-Janus tyrosine kinase 1/2-signal transducer and activator of transcription 1 signaling pathway,offering novel mechanistic insights and a promising therapeutic candidate for the future treatment of autoimmune disorders.展开更多
文摘Mesaconic acid has a special chemical structure and can undergo a series of reactions such as polymerization and addition. It is an important chemical intermediate and widely used in material, chemical and other industries. The chemical synthesis of mesaconic acid requires nitric acid, which is dangerous and harmful to the environment. The production of mesaconic acid by microbial fermentation has the characteristics of low raw material price, high efficiency and strong specificity, and thus a strong industrial application prospect. Mesaconic acid is an intermediate product of glutamic acid degradation pathway of microorganisms such as Clostridium tetani. However, at present, few reports have been conducted on the production of mesaconic acid by metabolic engineering microorganisms. In this study, glutamate mutase(GLM) and 3-methylaspartate ammonialyase(MAL) from C. tetani were recombined and expressed in Escherichia coli, and the obtained strain, BL21(DE3)/pETDuet-1-MAL-mutS-mutE, achieved the yield of mesaconic acid of 1.06 g/L. Compared with the wild type, the yields of mesaconic acid from mutants G133A and G133S increased by 21% and 16%, respectively. After 24 h of flask fermentation, the yields of mesaconic acid reached 1.28 and 1.23 g/L, respectively. This study can provide reference for microbial synthesis of mesaconic acid.
基金the National Natural Science Foundation of China(82170630,82470660,32171125,81971331)and the Tianjin Natural Science Foundation(22JCZDJC00520).
文摘Background and Aims:Autoimmune hepatitis(AIH)is a severe immune-mediated liver disease with limited treatment options beyond immunosuppressants,which carry significant side effects.Existing evidence suggests that mesaconate(MSA)possesses immunomodulatory properties and may offer advantages over itaconate derivatives by avoiding succinate dehydrogenase inhibition.However,its specific role in AIH remains unclear.This study aimed to investigate the therapeutic effects of MSA on AIH and to elucidate its underlying mechanisms of action.Methods:A murine AIH model was established via tail vein injection of concanavalin A(ConA,20mg/kg).MSA(250 mg/kg)was administered intraperitoneally 6 h before ConA exposure.Liver histology,serum transaminase levels,apoptosis markers,oxidative stress markers,and inflammatory cytokines were analyzed to assess the therapeutic efficacy of MSA.Additionally,RNA sequencing and Western blotting were performed to explore the mechanisms of MSA action.In vitro validation was conducted using RAW264.7 macrophages pretreated with MSA(1 mM)followed by interferon-gamma(IFN-Y,50 ng/mL)stimulation.Results:MSA pretreatment effectively mitigated ConA-induced AIH by reducing inflammatory responses,oxidative stress,and apoptosis both in vivo and in vitro.The underlying protective mechanisminvolved MSA-mediated downregulation of IFN-y expression and subsequent inhibition of the Janus tyrosine kinase 1/2-signal transducer and activator of transcription 1 signaling pathway.The involvement of this pathway in human AIH was also confirmed.Conclusions:This study provides the first evidence that MSA ameliorates AIH by suppressing the IFN-y-Janus tyrosine kinase 1/2-signal transducer and activator of transcription 1 signaling pathway,offering novel mechanistic insights and a promising therapeutic candidate for the future treatment of autoimmune disorders.
