Cholesterol-25-hydroxylase(CH25H)has been identified as an interferon-stimulated gene(ISG)in mammals that exerts its antiviral effects by catalyzing the conversion of cholesterol to 25-hydroxycholesterol(25HC).However...Cholesterol-25-hydroxylase(CH25H)has been identified as an interferon-stimulated gene(ISG)in mammals that exerts its antiviral effects by catalyzing the conversion of cholesterol to 25-hydroxycholesterol(25HC).However,invertebrates lack an antiviral system homologous to vertebrate interferons(IFNs)because the genomes of invertebrates do not encode IFN-like cytokines.Nevertheless,CH25H is present in insect genomes and it therefore deserves further study of whether and by which mechanism it could exert an antiviral effect in invertebrates.In this study,the Bombyx mori CH25H(BmCH25H)gene,of which the encoded protein has high homology with other lepidopteran species,was identified and located on chromosome 9.Interestingly,we found that the expression of BmCH25H was significantly upregulated in B.mori nucleopolyhedrovirus(BmNPV)-infected BmN cells and silkworm(B.mori)larvae at the early infection stage.The inhibitory effect of BmCH25H on BmNPV replication was further demonstrated to depend on its catalytic residues to convert cholesterol to 25HC.More importantly,we demonstrated that during BmNPV infection,BmCH25H expression was increased through the Janus kinase–signal transducer and activator of transcription(JAK–STAT)pathway,similar to the induction of ISGs following virus infection in vertebrates.This is the first report that CH25H has antiviral effects in insects;the study also elucidates the regulation of its expression and its mechanism of action.展开更多
Astrocytes are important cellular centers of cholesterol synthesis and metabolism that help maintain normal physiological function at the organism level.Spinal cord injury results in aberrant cholesterol metabolism by...Astrocytes are important cellular centers of cholesterol synthesis and metabolism that help maintain normal physiological function at the organism level.Spinal cord injury results in aberrant cholesterol metabolism by astrocytes and excessive production of oxysterols,which have profound effects on neuropathology.25-Hydroxycholesterol(25-HC),the main product of the membrane-associated enzyme cholesterol-25-hydroxylase(CH25H),plays important roles in mediating neuroinflammation.However,whether the abnormal astrocyte cholesterol metabolism induced by spinal cord injury contributes to the production of 25-HC,as well as the resulting pathological effects,remain unclear.In the present study,spinal cord injury-induced activation of thrombin was found to increase astrocyte CH25H expression.A protease-activated receptor 1 inhibitor was able to attenuate this effect in vitro and in vivo.In cultured primary astrocytes,thrombin interacted with protease-activated receptor 1,mainly through activation of the mitogen-activated protein kinase/nuclear factor-kappa B signaling pathway.Conditioned culture medium from astrocytes in which ch25h expression had been knocked down by siRNA reduced macrophage migration.Finally,injection of the protease activated receptor 1 inhibitor SCH79797 into rat neural sheaths following spinal cord injury reduced migration of microglia/macrophages to the injured site and largely restored motor function.Our results demonstrate a novel regulatory mechanism for thrombin-regulated cholesterol metabolism in astrocytes that could be used to develop anti-inflammatory drugs to treat patients with spinal cord injury.展开更多
Cholesterol-25-hydroxylase(CH25 H)is a membrane protein associated with endoplasmic reticulum,and it is an interferon-stimulated factor regulated by interferon.CH25 H catalyzes cholesterol to produce 25-hydroxycholest...Cholesterol-25-hydroxylase(CH25 H)is a membrane protein associated with endoplasmic reticulum,and it is an interferon-stimulated factor regulated by interferon.CH25 H catalyzes cholesterol to produce 25-hydroxycholesterol(25 HC)by adding a second hydroxyl to the 25 th carbon atom of cholesterol.Recent studies have shown that both CH25 H and 25 HC could inhibit the replication of many viruses.In this study,we found that ectopic expression of CH25 H in HEK-293 T and BHK-21 cell lines could inhibit the replication of Seneca Valley virus(SVV)and that there was no species difference.On the other hand,the knockdown of CH25 H could enhance the replication of SVV in HEK-293 T and BHK-21 cells,indicating the importance of CH25 H.To some extent,the CH25 H mutant without hydroxylase activity also lost its ability to inhibit SVV amplification.Further studies demonstrated that 25 HC was involved in the entire life cycle of SVV,especially in repressing its adsorption process.This study reveals that CH25 H exerts the advantage of innate immunity mainly by producing 25 HC to block virion adsorption.展开更多
基金supported by the Natural Science Foundation of Guangdong Basic and Applied Basic Research Fund(2022A1515012657)Guangzhou Science and Technology Plan Project(202002030218)+3 种基金National Natural Science Foundation of China(31872426)South China Agricultural University high-level talent launch projectGuangdong Provincial Promotion Project on Preservation and Utilization of Local Breed of Livestock and Poultry(No.2018-143)Innovation and Entrepreneurship Training Program for College Students in Guangdong Province(S202110564098).
文摘Cholesterol-25-hydroxylase(CH25H)has been identified as an interferon-stimulated gene(ISG)in mammals that exerts its antiviral effects by catalyzing the conversion of cholesterol to 25-hydroxycholesterol(25HC).However,invertebrates lack an antiviral system homologous to vertebrate interferons(IFNs)because the genomes of invertebrates do not encode IFN-like cytokines.Nevertheless,CH25H is present in insect genomes and it therefore deserves further study of whether and by which mechanism it could exert an antiviral effect in invertebrates.In this study,the Bombyx mori CH25H(BmCH25H)gene,of which the encoded protein has high homology with other lepidopteran species,was identified and located on chromosome 9.Interestingly,we found that the expression of BmCH25H was significantly upregulated in B.mori nucleopolyhedrovirus(BmNPV)-infected BmN cells and silkworm(B.mori)larvae at the early infection stage.The inhibitory effect of BmCH25H on BmNPV replication was further demonstrated to depend on its catalytic residues to convert cholesterol to 25HC.More importantly,we demonstrated that during BmNPV infection,BmCH25H expression was increased through the Janus kinase–signal transducer and activator of transcription(JAK–STAT)pathway,similar to the induction of ISGs following virus infection in vertebrates.This is the first report that CH25H has antiviral effects in insects;the study also elucidates the regulation of its expression and its mechanism of action.
基金supported by the National Natural Science Foundation of ChinaNo.81971826 (to AG)+5 种基金the China Postdoctoral Science FoundationNo.2020M681 689 (to YH)the Scientific Research Project of The Health Commission of Jiangsu ProvinceNo.ZDB2020003 (to AG)the Basic Scientific Research Projects of NantongNo.JC2020041 (to YH)
文摘Astrocytes are important cellular centers of cholesterol synthesis and metabolism that help maintain normal physiological function at the organism level.Spinal cord injury results in aberrant cholesterol metabolism by astrocytes and excessive production of oxysterols,which have profound effects on neuropathology.25-Hydroxycholesterol(25-HC),the main product of the membrane-associated enzyme cholesterol-25-hydroxylase(CH25H),plays important roles in mediating neuroinflammation.However,whether the abnormal astrocyte cholesterol metabolism induced by spinal cord injury contributes to the production of 25-HC,as well as the resulting pathological effects,remain unclear.In the present study,spinal cord injury-induced activation of thrombin was found to increase astrocyte CH25H expression.A protease-activated receptor 1 inhibitor was able to attenuate this effect in vitro and in vivo.In cultured primary astrocytes,thrombin interacted with protease-activated receptor 1,mainly through activation of the mitogen-activated protein kinase/nuclear factor-kappa B signaling pathway.Conditioned culture medium from astrocytes in which ch25h expression had been knocked down by siRNA reduced macrophage migration.Finally,injection of the protease activated receptor 1 inhibitor SCH79797 into rat neural sheaths following spinal cord injury reduced migration of microglia/macrophages to the injured site and largely restored motor function.Our results demonstrate a novel regulatory mechanism for thrombin-regulated cholesterol metabolism in astrocytes that could be used to develop anti-inflammatory drugs to treat patients with spinal cord injury.
基金supported by the National Natural Science Foundation of China(31772749,31572495)the Fundamental Research Funds for the Central Universities(2662017PY108)Natural Science Foundation of Hubei Province(2019CFA010)。
文摘Cholesterol-25-hydroxylase(CH25 H)is a membrane protein associated with endoplasmic reticulum,and it is an interferon-stimulated factor regulated by interferon.CH25 H catalyzes cholesterol to produce 25-hydroxycholesterol(25 HC)by adding a second hydroxyl to the 25 th carbon atom of cholesterol.Recent studies have shown that both CH25 H and 25 HC could inhibit the replication of many viruses.In this study,we found that ectopic expression of CH25 H in HEK-293 T and BHK-21 cell lines could inhibit the replication of Seneca Valley virus(SVV)and that there was no species difference.On the other hand,the knockdown of CH25 H could enhance the replication of SVV in HEK-293 T and BHK-21 cells,indicating the importance of CH25 H.To some extent,the CH25 H mutant without hydroxylase activity also lost its ability to inhibit SVV amplification.Further studies demonstrated that 25 HC was involved in the entire life cycle of SVV,especially in repressing its adsorption process.This study reveals that CH25 H exerts the advantage of innate immunity mainly by producing 25 HC to block virion adsorption.
