Spinal cord injury is a disabling condition with limited treatment options.Multiple studies have provided evidence suggesting that small extracellular vesicles(SEVs)secreted by bone marrow mesenchymal stem cells(MSCs)...Spinal cord injury is a disabling condition with limited treatment options.Multiple studies have provided evidence suggesting that small extracellular vesicles(SEVs)secreted by bone marrow mesenchymal stem cells(MSCs)help mediate the beneficial effects conferred by MSC transplantation following spinal cord injury.Strikingly,hypoxia-preconditioned bone marrow mesenchymal stem cell-derived SEVs(HSEVs)exhibit increased therapeutic potency.We thus explored the role of HSEVs in macrophage immune regulation after spinal cord injury in rats and their significance in spinal cord repair.SEVs or HSEVs were isolated from bone marrow MSC supernatants by density gradient ultracentrifugation.HSEV administration to rats via tail vein injection after spinal cord injury reduced the lesion area and attenuated spinal cord inflammation.HSEVs regulate macrophage polarization towards the M2 phenotype in vivo and in vitro.Micro RNA sequencing and bioinformatics analyses of SEVs and HSEVs revealed that mi R-146a-5p is a potent mediator of macrophage polarization that targets interleukin-1 receptor-associated kinase 1.Reducing mi R-146a-5p expression in HSEVs partially attenuated macrophage polarization.Our data suggest that HSEVs attenuate spinal cord inflammation and injury in rats by transporting mi R-146a-5p,which alters macrophage polarization.This study provides new insights into the application of HSEVs as a therapeutic tool for spinal cord injury.展开更多
Secretome derived from mesenchymal stem cells (MSCs) have profound effects on tissue regeneration, which could become the basis of future MSCs therapies. Hypoxia, as the physiologic environment of MSCs, has great pote...Secretome derived from mesenchymal stem cells (MSCs) have profound effects on tissue regeneration, which could become the basis of future MSCs therapies. Hypoxia, as the physiologic environment of MSCs, has great potential to enhance MSCs paracrine therapeutic effect. In our study, the paracrine effects of secretome derived from MSCs preconditioned in normoxia and hypoxia was compared through both in vitro functional assays and an in vivo rat osteochondral defect model. Specifically, the paracrine effect of total EVs were compared to that of soluble factors to characterize the predominant active components in the hypoxic secretome. We demonstrated that hypoxia conditioned medium, as well as the corresponding EVs, at a relatively low dosage, were efficient in promoting the repair of critical-sized osteochondral defects and mitigated the joint inflammation in a rat osteochondral defect model, relative to their normoxia counterpart. In vitro functional test shows enhancement through chondrocyte proliferation, migration, and matrix deposition, while inhibit IL-1β-induced chondrocytes senescence, inflammation, matrix degradation, and pro-inflammatory macrophage activity. Multiple functional proteins, as well as a change in EVs’ size profile, with enrichment of specific EV-miRNAs were detected with hypoxia preconditioning, implicating complex molecular pathways involved in hypoxia pre-conditioned MSCs secretome generated cartilage regeneration.展开更多
BACKGROUND Extracellular vesicles(EVs)derived from hypoxia-preconditioned(HP)mesenchymal stem cells(MSCs)have better cardioprotective effects against myocardial infarction(MI)in the early stage than EVs isolated from ...BACKGROUND Extracellular vesicles(EVs)derived from hypoxia-preconditioned(HP)mesenchymal stem cells(MSCs)have better cardioprotective effects against myocardial infarction(MI)in the early stage than EVs isolated from normoxic(NC)-MSCs.However,the cardioprotective mechanisms of HP-EVs are not fully understood.AIM To explore the cardioprotective mechanism of EVs derived from HP MSCs.METHODS We evaluated the cardioprotective effects of HP-EVs or NC-EVs from mouse adipose-derived MSCs(ADSCs)following hypoxia in vitro or MI in vivo,in order to improve the survival of cardiomyocytes(CMs)and restore cardiac function.The degree of CM apoptosis in each group was assessed by the terminal deoxynucleotidyl transferase dUTP nick end-labeling and Annexin V/PI assays.MicroRNA(miRNA)sequencing was used to investigate the functional RNA diversity between HP-EVs and NC-EVs from mouse ADSCs.The molecular mechanism of EVs in mediating thioredoxin-interacting protein(TXNIP)was verified by the dual-luciferase reporter assay.Co-immunoprecipitation,western blotting,and immunofluorescence were performed to determine if TXNIP is involved in hypoxia-inducible factor-1 alpha(HIF-1α)ubiquitination and degradation via the chromosomal region maintenance-1(CRM-1)-dependent nuclear transport pathway.RESULTS HP-EVs derived from MSCs reduced both infarct size(necrosis area)and apoptotic degree to a greater extent than NC-EVs from CMs subjected to hypoxia in vitro and mice with MI in vivo.Sequencing of EV-associated miRNAs showed the upregulation of 10 miRNAs predicted to bind TXNIP,an oxidative stress-associated protein.We showed miRNA224-5p,the most upregulated miRNA in HP-EVs,directly combined the 3’untranslated region of TXNIP and demonstrated its critical protective role against hypoxia-mediated CM injury.Our results demonstrated that MI triggered TXNIP-mediated HIF-1αubiquitination and degradation in the CRM-1-mediated nuclear transport pathway in CMs,which led to aggravated injury and hypoxia tolerance in CMs in the early stage of MI.CONCLUSION The anti-apoptotic effects of HP-EVs in alleviating MI and the hypoxic conditions of CMs until reperfusion therapy may partly result from EV miR-224-5p targeting TXNIP.展开更多
Hypoxic preconditioning refers to the exposure of organisms, systems, organs, tissues or cells to moderate hypoxia/ischemia that results in increased resistance to a subsequent episode of severe hypoxia/ischemia. In t...Hypoxic preconditioning refers to the exposure of organisms, systems, organs, tissues or cells to moderate hypoxia/ischemia that results in increased resistance to a subsequent episode of severe hypoxia/ischemia. In this article, we review recent research based on a mouse model of repeated exposure to autohypoxia. Pre-exposure markedly increases the tolerance to or protection against hypoxic insult, and preserves the cellular structure of the brain. Furthermore, the hippocampal activity amplitude and frequency of electroencephalogram, latency of cortical somatosensory-evoked potential and spinal somatosensory-evoked potential progressively decrease, while spatial learning and memory improve. In the brain, detrimental neurochemicals such as free radicals are down-regulated, while beneficial ones such as adenosine are up-regulated. Also, antihypoxia factor(s) and gene(s) are activated. We propose that the tolerance and protective effects depend on energy conservation and plasticity triggered by exposure to hypoxia via oxygen-sensing transduction pathways and hypoxia-inducible factor-initiated cascades. A potential path for further research is the development of devices and pharma-ceuticals acting on antihypoxia factor(s) and gene(s) for the prevention and treatment of hypoxia and related syndromes.展开更多
基金supported by the Fujian Minimally Invasive Medical Center Foundation,No.2128100514(to CC,CW,HX)the Natural Science Foundation of Fujian Province,No.2023J01640(to CC,CW,ZL,HX)。
文摘Spinal cord injury is a disabling condition with limited treatment options.Multiple studies have provided evidence suggesting that small extracellular vesicles(SEVs)secreted by bone marrow mesenchymal stem cells(MSCs)help mediate the beneficial effects conferred by MSC transplantation following spinal cord injury.Strikingly,hypoxia-preconditioned bone marrow mesenchymal stem cell-derived SEVs(HSEVs)exhibit increased therapeutic potency.We thus explored the role of HSEVs in macrophage immune regulation after spinal cord injury in rats and their significance in spinal cord repair.SEVs or HSEVs were isolated from bone marrow MSC supernatants by density gradient ultracentrifugation.HSEV administration to rats via tail vein injection after spinal cord injury reduced the lesion area and attenuated spinal cord inflammation.HSEVs regulate macrophage polarization towards the M2 phenotype in vivo and in vitro.Micro RNA sequencing and bioinformatics analyses of SEVs and HSEVs revealed that mi R-146a-5p is a potent mediator of macrophage polarization that targets interleukin-1 receptor-associated kinase 1.Reducing mi R-146a-5p expression in HSEVs partially attenuated macrophage polarization.Our data suggest that HSEVs attenuate spinal cord inflammation and injury in rats by transporting mi R-146a-5p,which alters macrophage polarization.This study provides new insights into the application of HSEVs as a therapeutic tool for spinal cord injury.
基金supported by National Medical Research Council of Singapore(MOH-000371-00)the National Research Foundation,Prime Minister’s Office,Singapore under its Campus for Research Excellence and Technological Enterprise(CREATE)program,through Singapore-MIT Alliance for Research and Technology(SMART):Critical Analytics for Manufacturing Personalized-Medicine(CAMP)Inter-Disciplinary Research Group.YY was supported by NUS Research Scholarship.
文摘Secretome derived from mesenchymal stem cells (MSCs) have profound effects on tissue regeneration, which could become the basis of future MSCs therapies. Hypoxia, as the physiologic environment of MSCs, has great potential to enhance MSCs paracrine therapeutic effect. In our study, the paracrine effects of secretome derived from MSCs preconditioned in normoxia and hypoxia was compared through both in vitro functional assays and an in vivo rat osteochondral defect model. Specifically, the paracrine effect of total EVs were compared to that of soluble factors to characterize the predominant active components in the hypoxic secretome. We demonstrated that hypoxia conditioned medium, as well as the corresponding EVs, at a relatively low dosage, were efficient in promoting the repair of critical-sized osteochondral defects and mitigated the joint inflammation in a rat osteochondral defect model, relative to their normoxia counterpart. In vitro functional test shows enhancement through chondrocyte proliferation, migration, and matrix deposition, while inhibit IL-1β-induced chondrocytes senescence, inflammation, matrix degradation, and pro-inflammatory macrophage activity. Multiple functional proteins, as well as a change in EVs’ size profile, with enrichment of specific EV-miRNAs were detected with hypoxia preconditioning, implicating complex molecular pathways involved in hypoxia pre-conditioned MSCs secretome generated cartilage regeneration.
基金Supported by National Natural Science Foundation of China,No. 81870264 and No. 81470546the Shanghai Committee of Science and Technology,No. 18411950500+1 种基金the Major Disease Joint Project of Shanghai Health System,No. 2014ZYJB0501Talent Cultivation Project of The Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine,No. JC202005
文摘BACKGROUND Extracellular vesicles(EVs)derived from hypoxia-preconditioned(HP)mesenchymal stem cells(MSCs)have better cardioprotective effects against myocardial infarction(MI)in the early stage than EVs isolated from normoxic(NC)-MSCs.However,the cardioprotective mechanisms of HP-EVs are not fully understood.AIM To explore the cardioprotective mechanism of EVs derived from HP MSCs.METHODS We evaluated the cardioprotective effects of HP-EVs or NC-EVs from mouse adipose-derived MSCs(ADSCs)following hypoxia in vitro or MI in vivo,in order to improve the survival of cardiomyocytes(CMs)and restore cardiac function.The degree of CM apoptosis in each group was assessed by the terminal deoxynucleotidyl transferase dUTP nick end-labeling and Annexin V/PI assays.MicroRNA(miRNA)sequencing was used to investigate the functional RNA diversity between HP-EVs and NC-EVs from mouse ADSCs.The molecular mechanism of EVs in mediating thioredoxin-interacting protein(TXNIP)was verified by the dual-luciferase reporter assay.Co-immunoprecipitation,western blotting,and immunofluorescence were performed to determine if TXNIP is involved in hypoxia-inducible factor-1 alpha(HIF-1α)ubiquitination and degradation via the chromosomal region maintenance-1(CRM-1)-dependent nuclear transport pathway.RESULTS HP-EVs derived from MSCs reduced both infarct size(necrosis area)and apoptotic degree to a greater extent than NC-EVs from CMs subjected to hypoxia in vitro and mice with MI in vivo.Sequencing of EV-associated miRNAs showed the upregulation of 10 miRNAs predicted to bind TXNIP,an oxidative stress-associated protein.We showed miRNA224-5p,the most upregulated miRNA in HP-EVs,directly combined the 3’untranslated region of TXNIP and demonstrated its critical protective role against hypoxia-mediated CM injury.Our results demonstrated that MI triggered TXNIP-mediated HIF-1αubiquitination and degradation in the CRM-1-mediated nuclear transport pathway in CMs,which led to aggravated injury and hypoxia tolerance in CMs in the early stage of MI.CONCLUSION The anti-apoptotic effects of HP-EVs in alleviating MI and the hypoxic conditions of CMs until reperfusion therapy may partly result from EV miR-224-5p targeting TXNIP.
基金supported by grants from the National Natural Science Foundation of China (3967087, 81060212, and 81160244)the Beijing Natural Science Foundation (7962009)+2 种基金the China Postdoctoral Science Foundation (20080430851)the Science Foundation of Shandong Province, China (ZR2010HM029)the Inner Mongolia Science Foundation (2010BS1104)
文摘Hypoxic preconditioning refers to the exposure of organisms, systems, organs, tissues or cells to moderate hypoxia/ischemia that results in increased resistance to a subsequent episode of severe hypoxia/ischemia. In this article, we review recent research based on a mouse model of repeated exposure to autohypoxia. Pre-exposure markedly increases the tolerance to or protection against hypoxic insult, and preserves the cellular structure of the brain. Furthermore, the hippocampal activity amplitude and frequency of electroencephalogram, latency of cortical somatosensory-evoked potential and spinal somatosensory-evoked potential progressively decrease, while spatial learning and memory improve. In the brain, detrimental neurochemicals such as free radicals are down-regulated, while beneficial ones such as adenosine are up-regulated. Also, antihypoxia factor(s) and gene(s) are activated. We propose that the tolerance and protective effects depend on energy conservation and plasticity triggered by exposure to hypoxia via oxygen-sensing transduction pathways and hypoxia-inducible factor-initiated cascades. A potential path for further research is the development of devices and pharma-ceuticals acting on antihypoxia factor(s) and gene(s) for the prevention and treatment of hypoxia and related syndromes.