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 damages. Methods: PDK4 and Hmgcs2 expression in the myocardium of diabetes mellitus (DM) model rats and HG-incubated cardiomyocyte line H9C2 were 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 co-immunoprecipitation 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. Conclusions: In summary, the silencing of PDK4 and Hmgcs2 alleviated HG-induced myocardial injuries through their interaction.

Background/Aim Uremic cardiomyopathy (UCM) is a characteristic cardiac pathology that is commonly found in patients with chronic kidney disease. This study dissected the mechanism of SPI1 in myocardial fibrosis and inflammation induced by UCM through S100A8/A9. Methods An UCM rat model was established, followed by qRT-PCR and western blot analyses of SPI1 and S100A8/A9 expression in myocardial tissues. After alterations of SPI1 and S100A8/A9 expression in UCM rats, the blood specimens were harvested from the cardiac apex of rats. The levels of creatine phosphokinase-MB (CK-MB), blood creatinine, blood urea nitrogen (BUN), and inflammatory cytokines (interleukin [IL]-6, IL-1β, and tumor necrosis factor-α [TNF-α]) were examined in the collected blood. Collagen fibrosis was assessed by Masson staining. The expression of fibrosis markers [transforming growth factor (TGF)-β1, α-smooth muscle actin (SMA), Collagen 4a1, and Fibronectin], IL-6, IL-1β, and TNF-α was measured in myocardial tissues. Chromatin immunoprecipitation and dual-luciferase reporter gene assays were conducted to test the binding relationship between SPI1 and S100A8/A9. Results S100A8/A9 and SPI1 were highly expressed in the myocardial tissues of UCM rats. Mechanistically, SPI1 bound to the promoter of S100A8/A9 to facilitate S100A8/A9 transcription. S100A8/A9 or SPI1 knockdown reduced myocardial fibrosis and inflammation and the levels of CK-MB, blood creatinine, and BUN, as well as the expression of TGF-β1, α-SMA, Collagen 4a1, Fibronectin, IL-6, TNF-α, and IL-1β in UCM rats. Conclusion SPI1 knockdown diminished S100A8/A9 transcription, thus suppressing myocardial fibrosis and inflammation caused by UCM.

Objectives Impacts of molecular pathways have been discussed recently on restenosis after percutaneous coronary intervention (PCI). Hence, this study aimed to explore the impact of calcineurin‐like phosphoesterase domain containing 1 (CPPED1) and specificity protein 1 (SP1) on restenosis after PCI. Methods A carotid balloon injury rat model was established, followed by western blot analysis of SP1 and CPPED1 expression in carotid artery (CA) tissues. After SP1 and CPPED1 were overexpressed, the neointimal hyperplasia and luminal stenosis were assessed. In addition, EPC underwent hypoxia/reoxygenation (H/R) treatment to construct an endothelial injury cell model. Then, cell proliferation, apoptosis, intracellular reactive oxygen species (ROS), and Ca2+ concentration were detected with cell counting kit‐8 (CCK‐8), flow cytometry, Chloromethyl‐2'7'‐dichlorofluorescein diacetate (CM‐H2DCFDA) penetrant, and Fluo‐4 AM staining, respectively. The binding relationship between SP1 and CPPED1 was verified by dual‐luciferase reporter and chromatin immunoprecipitation (ChIP) assays. Results SP1 and CPPED1 were lowly expressed in the model rats with carotid balloon injury. Mechanistically, SP1 bound to the promoter region of CPPED1 to activate CPPED1 expression. Overexpressing SP1 or CPPED1 lowered neointimal formation and restenosis rate, thus promoting the recovery of carotid balloon injury in rats. Meanwhile, SP1 and CPPED1 upregulation reduced ROS levels, Ca2+ concentration, and apoptosis of EPCs, accompanied by accelerated EPC viability. Conclusions SP1 or CPPED1 overexpression reduced neointimal formation and restenosis rate in carotid balloon injury.