Berberine （BBR） is a natural small molecule with various pharmacological activities and biological targets. BBR has been shown to inhibit mRNA decay in our previous studies, which is associated with its high binding...Berberine （BBR） is a natural small molecule with various pharmacological activities and biological targets. BBR has been shown to inhibit mRNA decay in our previous studies, which is associated with its high binding affinity to the poly-adenine （poly A） tail at the 3＇ end of mRNA. However, the exact mechanism remains unknown. In this research, we discovered that deficiency of cytoplasmic poly A binding protein （PABP）, which protects mRNA from nucleolytic attack as a poly A-PABP complex, led to the loss of BBR＇s effect on mRNA decay inhibition. We also demonstrated using fluorescence spectroscopy, RNA-EMSA （RNA-electrophoretic mobility shift assay） in vitro, and RIP （RNA immunoprecipitation） that BBR could significantly promote PABP binding to poly A. We might conclude that BBR could stabilize mRNA by enhancing the interaction between poly A and PABP. In addition, the HMBC （~H detected heteronuclear multiple bond correlation） studies demonstrated that BBR could bind to AMP, a monomer of poly A, directly and specifically. Further evidence of molecular docking suggested that BBR might act as a linker to stabilize the poly A-PABP, and elongate the half-life of mRNAs. This demonstrates that BBR might affect protein translation initiation and up-regulate protein expression.展开更多
Berberine （BBR） has a variety of pharmacological activities. Studies have reported that BBR not only reduces heat stress-induced fever but also inhibits lower body temperatures due to cold stress. Heat stress can be...Berberine （BBR） has a variety of pharmacological activities. Studies have reported that BBR not only reduces heat stress-induced fever but also inhibits lower body temperatures due to cold stress. Heat stress can be reduced via BBR treatment, which antagonizes HSP70-TNFa to regulate the body temperature alteration. In cold stress, however, the molecular mechanism of BBR-induced inhibition of hypothermia remains unclear. Therefore, we studied whether BBR promoted uncoupling protein 1 （UCP1, a crucial protein of thermogenesis） expression and its mechanism under cold stress. Wild type mice and Ucpl-/- mice were used for the in vivo experiments, and primary brown adipocytes and brown adipocytes HIB-1B were used for the in vitro studies. The cold stress was set at 4℃. The results showed that at 4℃, the body temperature of mice was decreased. BBR effectively inhibited this hypothermia. Simultaneously, Ucpl expression in brown adipose tissue （BAT） cells was significantly increased, and BBR promoted Ucpl expression. However, in Ucpl-knockout mice, the effect of BBR on hypothermia disappeared during cold stress, indicating that the main target for BBR regulation of body temperature was Ucpl. Further studies showed that the transcriptional response element NFE2 （nuclear factor erythroid-derived 2） in the upstream of the Ucpl promoter region contributed to the positive regulatory role on Ucpl expression at lower temperature. BBR could bind to the sequence of NFE2 response element in a temperature-dependent manner. Increased affinity of BBR binding to NFE2 response element in cold stress significantly strengthened and enhanced the expression of Ucpl. This work was important for understanding the role of BBR on thermogenesis in BAT, body temperature regulation and temperature tolerance under cold conditions.展开更多
基金National Natural Science Foundation of China(Grant No.81374006,81073092 and 90713043)
文摘Berberine （BBR） is a natural small molecule with various pharmacological activities and biological targets. BBR has been shown to inhibit mRNA decay in our previous studies, which is associated with its high binding affinity to the poly-adenine （poly A） tail at the 3＇ end of mRNA. However, the exact mechanism remains unknown. In this research, we discovered that deficiency of cytoplasmic poly A binding protein （PABP）, which protects mRNA from nucleolytic attack as a poly A-PABP complex, led to the loss of BBR＇s effect on mRNA decay inhibition. We also demonstrated using fluorescence spectroscopy, RNA-EMSA （RNA-electrophoretic mobility shift assay） in vitro, and RIP （RNA immunoprecipitation） that BBR could significantly promote PABP binding to poly A. We might conclude that BBR could stabilize mRNA by enhancing the interaction between poly A and PABP. In addition, the HMBC （~H detected heteronuclear multiple bond correlation） studies demonstrated that BBR could bind to AMP, a monomer of poly A, directly and specifically. Further evidence of molecular docking suggested that BBR might act as a linker to stabilize the poly A-PABP, and elongate the half-life of mRNAs. This demonstrates that BBR might affect protein translation initiation and up-regulate protein expression.
基金National Natural Science Foundation of China(Grant No.81374006,81073092 and 90713043)
文摘Berberine （BBR） has a variety of pharmacological activities. Studies have reported that BBR not only reduces heat stress-induced fever but also inhibits lower body temperatures due to cold stress. Heat stress can be reduced via BBR treatment, which antagonizes HSP70-TNFa to regulate the body temperature alteration. In cold stress, however, the molecular mechanism of BBR-induced inhibition of hypothermia remains unclear. Therefore, we studied whether BBR promoted uncoupling protein 1 （UCP1, a crucial protein of thermogenesis） expression and its mechanism under cold stress. Wild type mice and Ucpl-/- mice were used for the in vivo experiments, and primary brown adipocytes and brown adipocytes HIB-1B were used for the in vitro studies. The cold stress was set at 4℃. The results showed that at 4℃, the body temperature of mice was decreased. BBR effectively inhibited this hypothermia. Simultaneously, Ucpl expression in brown adipose tissue （BAT） cells was significantly increased, and BBR promoted Ucpl expression. However, in Ucpl-knockout mice, the effect of BBR on hypothermia disappeared during cold stress, indicating that the main target for BBR regulation of body temperature was Ucpl. Further studies showed that the transcriptional response element NFE2 （nuclear factor erythroid-derived 2） in the upstream of the Ucpl promoter region contributed to the positive regulatory role on Ucpl expression at lower temperature. BBR could bind to the sequence of NFE2 response element in a temperature-dependent manner. Increased affinity of BBR binding to NFE2 response element in cold stress significantly strengthened and enhanced the expression of Ucpl. This work was important for understanding the role of BBR on thermogenesis in BAT, body temperature regulation and temperature tolerance under cold conditions.
