MicroRNA-22-3p Restrains the Proliferation, Phenotypic Transformation, and Migration of Vascular Smooth Muscle Cells by Manipulating TOMM40.

microRNA (miR) -22-3p has been confirmed to be engaged in the phenotype transformation and proliferation of vascular smooth muscle cells (VSMCs), which is intimately correlated with restenosis. The current research set out to explore the detailed mechanism and function of miR-22-3p in VSMC proliferation, phenotype transformation, and migration via the translocase of outer mitochondrial membrane (TOMM40). Peripheral blood samples were acquired from patients with in-stent restenosis (ISR) after percutaneous coronary intervention (PCI), with subsequent quantitative reverse transcription (qRT) -polymerase chain reaction (PCR) and Western blot analyses of miR-22-3p and TOMM40 expression. After miR-22-3p-inhibitor, oe-TOMM40, and sh-TOMM40 were transfected into VSMCs, Cell Counting Kit (CCK) -8 assay, scratch test, and Western blot analysis were implemented to measure the VSMC proliferation, migration, and matrix metallopeptidase 9 (MMP9), α-smooth muscle actin (SMA), smooth muscle-myosin heavy chain (SM-MHC), and osteopontin (OPN) expressions, respectively. In addition, human umbilical vein endothelial cell (HUVEC) proliferation was examined by CCK-8 assay. The binding relationship between miR-22-3p and TOMM40 was assessed by dual luciferase reporter and RNA immunoprecipitation assays. The peripheral blood of patients with ISR after PCI had low expression of miR-22-3p and high expression of TOMM40. The mechanistic analysis reported the negative targeting relationship between miR-22-3p and TOMM40. Down-regulating miR-22-3p or up-regulating TOMM40 elevated the proliferation, migration, and phenotype transformation of VSMCs. miR-22-3p inhibitor had no evident impact on HUVEC proliferation. In addition, rescue assays displayed that TOMM40 silencing annulled miR-22-3p inhibition-enhanced VSMC proliferation, migration, and phenotype transformation. Conclusively, miR-22-3p could repress VSMC proliferation, phenotypic transformation, and migration by targeting TOMM40, which might be a possible treatment candidate for restenosis after PCI in patients with cardiovascular disease.

Protein PDK4 Interacts with HMGCS2 to Facilitate High Glucoseinduced Myocardial Injuries.

OBJECTIVES: As a distinct type of cardiomyopathy, diabetic cardiomyopathy (DCM) is featured as diastolic or systolic cardiac dysfunction in diabetic patients. In order to broaden the understanding of molecular mechanisms in DCM, we intended to explore the mechanism of the interaction between PDK4 protein and Hmgcs2 in high glucose (HG)-induced myocardial damage. METHODS: PDK4 and Hmgcs2 expression in the myocardium of diabetes mellitus (DM) model rats and HG-incubated cardiomyocyte line H9C2 was analyzed by western blot analysis. Echocardiography and TUNEL assay were utilized for respective assessment of cardiac structure and function and cardiomyocyte apoptosis in DM rats after silencing PDK4 or/and Hmgcs2. In vitro, the impact of PDK4 and Hmgcs2 on HG-induced cardiomyocyte injuries was identified with cell counting kit-8 and flow cytometry assays, along with detection of LDH release, caspase-3/7 activities, and reactive oxygen species (ROS) and malondialdehyde (MDA) levels. Moreover, a coimmunoprecipitation assay was utilized to test the interaction between PDK4 and Hmgcs2. RESULTS: Both PDK4 and Hmgcs2 were highly expressed in the myocardial tissues of DM rats. Mechanistically, PDK4 interacted with Hmgcs2 to upregulate Hmgcs2 expression in HG-induced H9C2 cells. Silencing PDK4 improved cardiac function and reduced cardiomyocyte apoptosis in DM rats. In HG-induced H9C2 cells, PDK4 or Hmgcs2 silencing enhanced cell viability and reduced LDH release, caspase-3/7 activities, cell apoptosis, and ROS and MDA levels, and these trends were further promoted by the simultaneous silencing of PDK4 and Hmgcs2. CONCLUSION: In summary, the silencing of PDK4 and Hmgcs2 alleviated HG-induced myocardial injuries through their interaction.