Extracellular vesicles from hypoxia-preconditioned mesenchymal stem cells alleviates myocardial injury by targeting thioredoxin-interacting protein-mediated hypoxia-inducible factor-1α pathway.

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-1α ubiquitination 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.

VSTM1 regulates monocyte/macrophage function via the NF-κB signaling pathway.

OBJECTIVE: V-set and transmembrane domain-containing protein 1 (VSTM1) is negatively correlated with inflammation. However, its effect on atherosclerosis (AS) remains largely unexplored. In this study, we aimed to assess the effect of VSTM1 on the biological function of human peripheral blood mononuclear cells /macrophages stimulated by oxidized low-density lipoprotein (ox-LDL). METHODS: U937 cells were divided into three groups as follows: control group, pLenti-VSTM1 shRNA group (VSTM1 depletion), and pLenti-VSTM1 group (VSTM1 overexpression). Cellular migration, chemotaxis, apoptosis, and secretion of inflammatory factors of monocytes/macrophages stimulated by ox-LDL were studied. RESULTS: Overexpression of VSTM1 decreased the proliferation of U937 cells and induced cellular apoptosis. Depletion of VSTM1 enhanced the invasiveness and chemotaxis, increased the inflammatory response, and reduced the incidence of cell necrosis and apoptosis. Nuclear factor κ of B cells (NF-κB) was activated in VSTM1-depleted U937 cells. CONCLUSION: VSTM1 might play an important role in the activation of monocytes/macrophages and participate in the pathogenesis of AS via regulating NF-κB activity.

Predictive and prognostic value of v-set and transmembrane domain-containing 1 expression in monocytes for coronary artery disease.

The aim of this study was to investigate the correlation between v-set and transmembrane domain-containing 1 (VSTM1) expression and incidence of major adverse cardiac events (MACE) in patients with coronary heart disease (CHD). A total of 310 patients were divided into a non-acute coronary syndrome (non-ACS) group (containing the stable angina group, and the asymptomatic coronary artery diseaseand other patients group) and an ACS group (containing unstable angina and acute myocardial infarction patients). Monocytic VSTM1 expression levels (assessed via average fluorescence intensity derived from antibody binding to VSTM1) in each group were detected and analyzed. The cut-off value of monocytic VSTM1 expression to predict the onset of ACS and MACE was confirmed. VSTM1 expression in monocytes from the ACS group was lower than that of the non-ACS group. The incidence of MACEs in the high VSTM1-expression group was much less than that of those in the low VSTM1 expression group at the 1 year follow-up stage. VSTM1 expression had an independent-inversed association with increased incidence of MACE and ACS. VSTM1 expression in monocytes may help to predict the occurrence of ACS in patients with CHD, and moreover it may provide the means to evaluate MACE prognosis during CHD patient follow-up.

Formation of a built-in field at the porphyrin/ITO interface directly proven by the time-resolved photovoltage technique.

Two assemblies, porphyrin powder/ITO and porphyrin film/ITO, were built by a facile method. The time-resolved photovoltage technique was utilized to prove the behaviour of photo-induced charges in the two assemblies. The photovoltage results show that the porphyrin film/ITO assembly displays a reversal polarity response, which is different from the response of porphyrin powder/ITO. This phenomenon is due to the effect of a built-in field on photo-induced charge behaviour at the porphyrin film/ITO interface. This result is beneficial for the development of a measuring method for detecting heterojunction interface formation and understanding the photoelectric process in photoelectric materials and devices.