Many sources of stress cause accumulation of unfolded or misfolded proteins in endoplasmic reticulum(ER), which elicits the unfolded protein response(UPR) to either promote cell survival or programmed cell death depen...Many sources of stress cause accumulation of unfolded or misfolded proteins in endoplasmic reticulum(ER), which elicits the unfolded protein response(UPR) to either promote cell survival or programmed cell death depending on different developmental context or stress severity. The Arabidopsis membrane-associated transcription factor, b ZIP28, is the functional equivalent of mammalian ATF6, which relocates from the ER to the Golgi where it is proteolytically processed and released from the membrane to the nucleus to mediate the UPR. Although the canonical site-1 protease(S1P) cleavage site on the ER lumen-facing domain is well conserved between b ZIP28 and ATF6, the importance of S1 P cleavage on b ZIP28 has not been experimentally demonstrated. Here we provide genetic evidence that the RRIL573 site, but not the RVLM373 site, on the lumen-facing domain of bZ IP28 is critical for the biological function of b ZIP28 under ER stress condition. Further biochemistry and cell biology studies demonstrated that the RRIL573 site, but not the RVLM373 site, is required for proteolytic processing and nuclear relocation of b ZIP28 in response to ER stress. Our results reveal that S1 P cleavage site plays a pivotal role in activation and function of b ZIP28 during UPR in plants.展开更多
A rapid and sensitive liquid chromatography–tandem mass spectrometry(LC–MS/MS) method was developed and validated for the simultaneous determination of H002 and its phosphorylated metabolite, H002-P and hydroxylated...A rapid and sensitive liquid chromatography–tandem mass spectrometry(LC–MS/MS) method was developed and validated for the simultaneous determination of H002 and its phosphorylated metabolite, H002-P and hydroxylated metabolite H002-M, in rat blood. H001, an analogue of H002, was used as the internal standard.Blood samples were prepared by simple protein precipitation. The analytes and internal standard were separated on a Zorbax SB-C18 column with a gradient mobile phase consisting of methanol and water containing 0.1% formic acid at a flow rate of 0.2 mL /min with an operating temperature of 20 1C. The detection was performed on a triple quadrupole tandem mass spectrometer with positive electrospray ionization in multiple-reaction monitoring mode.Linear detection responses were obtained from 0.2–100 ng/mL for H002 and H002-M, while 0.5–100 ng/mL for H002-P. The intra- and inter-day precision(RSD%) was within 11.76%, with the accuracy(RE%) ranging from –9.84% to 9.12%. The analytes were shown to be stable during sample storage, preparation and analytic procedures.The method was applied to determine the pharmacokinetics of H002 in rats, and a preliminary study showed that the pharmacokinetics of H002 correlated with its biological effect on peripheral blood lymphocytes.展开更多
The mechanism of sphingosine-1-phosphate(S1P)-mediated phagocytosis remains unknown.Here,we found that S1P or FTY720(an analog of S1P)promoted microglial phagocytosis in stroke independent of S1PRs.First,we used compu...The mechanism of sphingosine-1-phosphate(S1P)-mediated phagocytosis remains unknown.Here,we found that S1P or FTY720(an analog of S1P)promoted microglial phagocytosis in stroke independent of S1PRs.First,we used computer simulation of molecular docking to predict that S1P might be a ligand for triggering receptor expressed on myeloid cells 2(TREM2).Next,microscale thermophoresis(MST),surface plasmon resonance(SPR)and liquid chromatography–tandem mass spectrometry(LC–MS/MS)were performed to reveal that S1P was a novel TREM2 ligand.Then,we confirmed the pro-phagocytosis of S1P targeting in Trem2-Dap12 transfected CHO cells and TREM2 knockdown microglia.Point mutation analysis showed that D104 was the critical binding residue.Trem2^(−/−)mice were used to demonstrate the role of S1P-induced phagocytosis targeting on TREM2 in protecting against ischemic brain injury.Finally,further studies revealed that apolipoprotein E(APOE)loaded with S1P was released by microglia and bound to apoptotic neurons via LDL receptor related protein 1B(LRP1B)and thereby induced microglia to phagocytose apoptotic neurons.Overall,the present work reveals for the first time that S1P acts as a novel endogenous ligand of TREM2 to effectively promote microglial phagocytosis.Our findings provide a new lead compound for developing immunomodulator targeting on TREM2.展开更多
FTY720, a sphingosine 1-phosphate receptor modulator, induces a marked decrease in the number of peripheral blood lymphocytes and exerts immunomodulating activity in various experimental allograft and autoimmune disea...FTY720, a sphingosine 1-phosphate receptor modulator, induces a marked decrease in the number of peripheral blood lymphocytes and exerts immunomodulating activity in various experimental allograft and autoimmune disease models. In this study, we evaluated the effect of FTY720 and its active metabolite, （S）-enantiomer of FTY720-phosphate [（S）-FTY720-P] on experimental autoimmune encephalomyelitis （EAE） in rats and mice. Prophylactic administration of FTY720 at 0.1 to 1 mg/kg almost completely prevented the development of EAE, and therapeutic treatment with FTY720 significantly inhibited the progression of EAE and EAE-associated histological change in the spinal cords of LEW rats induced by immunization with myelin basic protein. Consistent with rat EAE, the development of proteolipid protein-induced EAE in SJL/J mice was almost completely prevented and infiltration of CD4^＋ T cells into spinal cord was decreased by prophylactic treatment with FTY720 and （S）-FTY720-P. When FTY720 or （S）-FTY720-P was given after establishment of EAE in SJL/J mice, the relapse of EAE was markedly inhibited as compared with interferon-β, and the area of demyelination and the infiltration of CD4^＋ T cells were decreased in spinal cords of EAE mice. Similar therapeutic effect by FTY720 was obtained in myelin oligodendrocyte glycoprotein-induced EAE in C57BL/6 mice. These results indicate that FTY720 exhibits not only a prophylactic but also a therapeutic effect on EAE in rats and mice, and that the effect of FTY720 on EAE appears to be due to a reduction of the infiltration of myelin antigen-specific CD4^＋ T cells into the inflammation site. Cellular ＆ Molecular Immunology. 2005;2（6）：439-448.展开更多
基金supported by grants from the National Basic Research Program of China(973 Program,2012CB910500)the National Natural Science Foundation of China(31171157,31222008)the Specialized Research Fund for the Doctoral Program of Higher Education(20130071110011)
文摘Many sources of stress cause accumulation of unfolded or misfolded proteins in endoplasmic reticulum(ER), which elicits the unfolded protein response(UPR) to either promote cell survival or programmed cell death depending on different developmental context or stress severity. The Arabidopsis membrane-associated transcription factor, b ZIP28, is the functional equivalent of mammalian ATF6, which relocates from the ER to the Golgi where it is proteolytically processed and released from the membrane to the nucleus to mediate the UPR. Although the canonical site-1 protease(S1P) cleavage site on the ER lumen-facing domain is well conserved between b ZIP28 and ATF6, the importance of S1 P cleavage on b ZIP28 has not been experimentally demonstrated. Here we provide genetic evidence that the RRIL573 site, but not the RVLM373 site, on the lumen-facing domain of bZ IP28 is critical for the biological function of b ZIP28 under ER stress condition. Further biochemistry and cell biology studies demonstrated that the RRIL573 site, but not the RVLM373 site, is required for proteolytic processing and nuclear relocation of b ZIP28 in response to ER stress. Our results reveal that S1 P cleavage site plays a pivotal role in activation and function of b ZIP28 during UPR in plants.
基金supported by the National Science and Technology Major Project of China(Nos.2012ZX09301002-001-007 and2012ZX09301002-006)National Natural Science Foundation of China(NSFC,Nos.81202545,81302847 and 81473096)
文摘A rapid and sensitive liquid chromatography–tandem mass spectrometry(LC–MS/MS) method was developed and validated for the simultaneous determination of H002 and its phosphorylated metabolite, H002-P and hydroxylated metabolite H002-M, in rat blood. H001, an analogue of H002, was used as the internal standard.Blood samples were prepared by simple protein precipitation. The analytes and internal standard were separated on a Zorbax SB-C18 column with a gradient mobile phase consisting of methanol and water containing 0.1% formic acid at a flow rate of 0.2 mL /min with an operating temperature of 20 1C. The detection was performed on a triple quadrupole tandem mass spectrometer with positive electrospray ionization in multiple-reaction monitoring mode.Linear detection responses were obtained from 0.2–100 ng/mL for H002 and H002-M, while 0.5–100 ng/mL for H002-P. The intra- and inter-day precision(RSD%) was within 11.76%, with the accuracy(RE%) ranging from –9.84% to 9.12%. The analytes were shown to be stable during sample storage, preparation and analytic procedures.The method was applied to determine the pharmacokinetics of H002 in rats, and a preliminary study showed that the pharmacokinetics of H002 correlated with its biological effect on peripheral blood lymphocytes.
基金supported by the National Natural Science Foundation of China (Nos.81973301, 82003732 and 81773701)the Medical Research Project of Jiangsu Commission of Health (No.ZDA2020006, China)+3 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (No.18KJA310004)the Major Project of Nanjing Medical University (No.NMUD2018008, China)the Postgraduate Research and Practice Innovation Program of Jiangsu Province (Nos.KYCX19_1121 and KYCX20_1417, China)Priority Academic Program Development of Jiangsu Higer Education Institutions (China)
文摘The mechanism of sphingosine-1-phosphate(S1P)-mediated phagocytosis remains unknown.Here,we found that S1P or FTY720(an analog of S1P)promoted microglial phagocytosis in stroke independent of S1PRs.First,we used computer simulation of molecular docking to predict that S1P might be a ligand for triggering receptor expressed on myeloid cells 2(TREM2).Next,microscale thermophoresis(MST),surface plasmon resonance(SPR)and liquid chromatography–tandem mass spectrometry(LC–MS/MS)were performed to reveal that S1P was a novel TREM2 ligand.Then,we confirmed the pro-phagocytosis of S1P targeting in Trem2-Dap12 transfected CHO cells and TREM2 knockdown microglia.Point mutation analysis showed that D104 was the critical binding residue.Trem2^(−/−)mice were used to demonstrate the role of S1P-induced phagocytosis targeting on TREM2 in protecting against ischemic brain injury.Finally,further studies revealed that apolipoprotein E(APOE)loaded with S1P was released by microglia and bound to apoptotic neurons via LDL receptor related protein 1B(LRP1B)and thereby induced microglia to phagocytose apoptotic neurons.Overall,the present work reveals for the first time that S1P acts as a novel endogenous ligand of TREM2 to effectively promote microglial phagocytosis.Our findings provide a new lead compound for developing immunomodulator targeting on TREM2.
文摘FTY720, a sphingosine 1-phosphate receptor modulator, induces a marked decrease in the number of peripheral blood lymphocytes and exerts immunomodulating activity in various experimental allograft and autoimmune disease models. In this study, we evaluated the effect of FTY720 and its active metabolite, （S）-enantiomer of FTY720-phosphate [（S）-FTY720-P] on experimental autoimmune encephalomyelitis （EAE） in rats and mice. Prophylactic administration of FTY720 at 0.1 to 1 mg/kg almost completely prevented the development of EAE, and therapeutic treatment with FTY720 significantly inhibited the progression of EAE and EAE-associated histological change in the spinal cords of LEW rats induced by immunization with myelin basic protein. Consistent with rat EAE, the development of proteolipid protein-induced EAE in SJL/J mice was almost completely prevented and infiltration of CD4^＋ T cells into spinal cord was decreased by prophylactic treatment with FTY720 and （S）-FTY720-P. When FTY720 or （S）-FTY720-P was given after establishment of EAE in SJL/J mice, the relapse of EAE was markedly inhibited as compared with interferon-β, and the area of demyelination and the infiltration of CD4^＋ T cells were decreased in spinal cords of EAE mice. Similar therapeutic effect by FTY720 was obtained in myelin oligodendrocyte glycoprotein-induced EAE in C57BL/6 mice. These results indicate that FTY720 exhibits not only a prophylactic but also a therapeutic effect on EAE in rats and mice, and that the effect of FTY720 on EAE appears to be due to a reduction of the infiltration of myelin antigen-specific CD4^＋ T cells into the inflammation site. Cellular ＆ Molecular Immunology. 2005;2（6）：439-448.
