Bone marrow mesenchymal stem cell-derived exosomes carrying E3 ubiquitin ligase ITCH attenuated cardiomyocyte apoptosis by mediating apoptosis signal-regulated kinase-1.

BACKGROUND: Bone marrow mesenchymal stem cell (BMSC)-derived exosomes have been verified to perform an effective role in treating acute myocardial infarction (MI). Herein, we aimed to investigate the role of BMSC-derived exosomes carrying itchy E3 ubiquitin ligase (ITCH) in MI and the underlying mechanism involved. METHODS: BMSCs were isolated from rat bone marrow and exosomes were extracted using ultra-high speed centrifugation. Exosomes uptake by cardiomyoblasts was determined by PKH-67 staining. Rat cardiomyoblast cell line H9C2 was stimulated by hypoxia, as in vitro model. H9C2 cell apoptosis was determined by flow cytometry. Cell viability was examined by cell counting kit-8 assay. Western blotting was performed to determine the expression of ITCH, apoptosis signal-regulated kinase-1 (ASK1), and apoptotic-related protein cleaved-caspase 3 and Bcl-2. Ubiquitination assay was employed to measure the levels of ASK1 ubiquitination. RESULTS: Exosomes derived from BMSCs were endocytosed by H9C2 cardiomyoblasts. BMSC-Exo downregulated cleaved-caspase 3 expression, upregulated Bcl-2 expression, further suppressed H9C2 cell apoptosis under hypoxia treatment, meanwhile the expression of ASK1 was downregulated, and similar effects were observed in BMSC-cultured supernatant (BMSC-S). However, these effects were reversed by exosome inhibitor GW4869. BMSC-derived exosomes enhanced ASK1 ubiquitination and degradation. Mechanically, exosomes of ITCH-knockdown BMSCs promoted H9C2 cell apoptosis and upregulated ASK1 expression. Overexpression of ITCH enhanced ASK1 ubiquitination and degradation. Further, the protein expression of ASK1 and cleaved-caspase 3 was upregulated and Bcl-2 protein expression was downregulated. ITCH-knockdown BMSC exosomes increased cardiomyoblast apoptosis. CONCLUSION: BMSC-derived exosomes carrying ITCH suppressed cardiomyoblast apoptosis, promoted cardiomyoblast viability, and improved myocardial injury in AMI by mediating ASK1 ubiquitination.

Multiple Primary Cardiac Malignant Peripheral Nerve Sheath Tumors in the Left Atrium: Case Report.

Malignant peripheral nerve sheath tumors are rare sarcomas of the heart. Herein, we report the case of a 24-year-old man who complained of dyspnea, cough, and upper left back pain. He was found to have multiple primary heart tumors obstructing the right superior pulmonary vein in the left atrium, which were diagnosed as malignant peripheral nerve sheath tumors. The patient underwent successful resection of the tumors and immunohistochemistry was utilized for diagnosis.

Genetic factors contribute to patient-specific warfarin dose for Han Chinese.

BACKGROUND: Warfarin is a commonly prescribed anticoagulant drug for the prevention of thromboses. To address the association of genetic factors and warfarin dosage for ethnic Han Chinese, we genotyped six candidate genes involved in the warfarin interactive pathway with focus on SNPs with reported association with warfarin dose. METHODS: We recruited a study population consisted of 318 patients receiving warfarin treatment and 995 healthy controls. PCR and direct sequencing were used to identify the sequence polymorphisms. RESULTS: In our study population, SNP rs1799853 of CYP2C9, rs1687390 of ORM1-2, and rs2069919 of PROC showed no variation. SNPs rs12714145 of GGCX and rs1799809 of PROC showed no significant correlation with warfarin dose. The associations of SNPs rs9934438 and rs9923231 of VKORC1, the 3 (rs1057910) and C(-65) (rs9332127) alleles of CYP2C9, and SNP rs4653436 of EPHXI with the dose of warfarin were significant. CONCLUSION: A multiple regression model based on the genetic polymorphisms of VKORC1, CYP2C9, EPHX1 and the non-genetic factors of age and body weight can explain 40.2% of the variance in warfarin dose in Han Chinese patients. Translation of this knowledge into clinical guidelines for warfarin prescription may improve the safety and efficacy of warfarin treatment among Han Chinese.