Protective effect of Pulsatilla saponin A on acute myocardial infarction via miR-24-3p/p16.

The effect of Pulsatilla saponin A (PsA) on acute myocardial infarction (AMI) was unknown. This study targeted to examine the roles of PsA on hypoxia-triggered toxicity to H9c2 cells and reveal the potential mechanism. H9c2 cells were maintained under a hypoxic environment for 12 h to construct the AMI cell model and the cells were pretreated by PsA. Hypoxia triggered toxicity to H9c2 cells and the anti-toxicity effect of PsA was evaluated by CCK8, TUNEL, and Western blot. The levels of miR-24-3p and p16 in H9c2 cells, AMI group tissues, and their respective controls were assessed using qRT-PCR. The dual-luciferase assay was applied to verify the targeting mechanism of miR-24-3p on p16. Then the effects of miR-24-3p inhibitor or/and si-p16 on H9c2 cells treated with PsA under hypoxia were detected by CCK8, TUNEL, and Western blot. Flow cytometry was executed to determine the cell cycle. Hypoxia decreased viability and proliferation and increased apoptosis of H9c2 cells, which were ameliorated by PsA pretreatment. The level of miR-24-3p was diminished, but p16 expression was elevated in hypoxia-treated cells and AMI group tissues. MiR-24-3p could sponge p16 in hypoxia-treated cells. Furthermore, the impact of applying miR-24-3p inhibitor on PsA and hypoxia-treated cells could be reversed by si-p16. PsA relieved hypoxia-triggered cell toxicity via miR-24-3p/p16 axis. These findings provided some fresh insights into the potential therapeutic effects of the application of PsA in AMI.

MicroRNA-325 facilitates atherosclerosis progression by mediating the SREBF1/LXR axis via KDM1A.

AIMS: MicroRNA-325 (miR-325) was significantly upregulated in diabetic atherosclerosis, while its specific role in atherosclerosis has not been established. The present study was set to probe the effects of miR-325 on the atherosclerosis progression and to explore the mechanisms. MATERIALS AND METHODS: The ApoE-/- mouse with atherosclerosis was developed to detect the miR-325 expression in atherosclerotic plaques. The pathological symptoms of atherosclerotic mice were observed by injection of miR-325 mimic or inhibitor. Subsequently, the levels of CRP, IL-6, IL-1ß and TNF-ɑ in mouse serum were measured by ELISA. Then, miR-325 was overexpressed or silenced in RAW264.7-derived foam cells (FCs), and cholesterol efflux and lipid content were evaluated. Furthermore, miR-325 expression was altered in HA-VSMCs to measure viability and apoptosis. The targets of miR-325 were predicted in a bioinformatics website, and the expression of KDM1A, SREBF1 and PPARγ-LXR-ABCA1 in mouse arterial tissues and cells was detected, followed by rescue experiments. KEY FINDINGS: miR-325 was elevated in arterial tissues of atherosclerotic mice, and miR-325 inhibition in mice reduced the contents of total cholesterol, triglyceride, low-density lipoprotein, and CRP, IL-6, IL-1ß and TNF-ɑ levels in mouse serum. miR-325 inhibitor facilitated the cholesterol efflux and decreased the lipid content in RAW264.7 cells, and also diminished HA-VSMC viability. miR-325 targeted KDM1A to reduce SREBF1 expression, and further KDM1A suppression inhibited cholesterol efflux in RAW264.7 cells and the activation of PPARγ-LXR-ABCA1 pathway. SIGNIFICANCE: miR-325 lowers SREBF1 expression by decreasing KDM1A expression, thereby inhibiting the activation of the PPARγ-LXR-ABCA1 pathway and thus promoting atherosclerosis.

Lixisenatide enhances mitochondrial biogenesis and function through regulating the CREB/PGC-1α pathway.

Mitochondrial dysregulation has been associated with vascular endothelial dysfunction and pathophysiological development of cardiovascular diseases. Lixisenatide is a drug approved by the US Food and Drug Administration for the treatment of type 2 diabetes (T2D). Little information regarding the effects of lixisenatide on mitochondrial function in endothelial cells has been reported before. In the current study, we found that treatment with lixisenatide significantly increased the expression of PGC-1α, a "molecular switch" of mitochondrial biogenesis in human umbilical vein endothelial cells (HUVECs). Lixisenatide treatment also promoted the expressions of NRF1 and TFAM, which are the target genes of PGC-1α and executors of mitochondrial biogenesis. Importantly, our results indicate that lixisenatide treatment promoted mitochondrial biogenesis by elevating the ratio of mitochondrial-to-nuclear DNA (mtDNA/nDNA), mitochondrial mass, cytochrome B expression, and citrate synthase activity in HUVECs. Correspondingly, we found that lixisenatide treatment led to a functional gain and improvement in mitochondria by increasing the mitochondrial respiration rate and ATP generation. Mechanistically, lixisenatide treatment induced the phosphorylation of CREB at Ser133. Blockage of CREB phosphorylation using its inhibitor H89 abolished the effects of lixisenatide on the activation of PGC-1α/NRF-1/TFAM as well as the increase in mtDNA/nDNA. These findings suggest that lixisenatide promoted mitochondrial biogenesis in endothelial cells through activating the PGC-1α signaling pathway, which is mediated by the transcriptional factor CREB.

Effect of Puerarin on Expression of ICAM-1 and TNF-α in Kidneys of Diabetic Rats.

BACKGROUND: As an important factor causing end-stage renal disease, diabetic nephropathy is correlated with low-grade chronic inflammation and immune system activation. This study aimed to investigate the protective function of puerarin on the kidneys of diabetic rats. MATERIAL AND METHODS: A cohort of healthy male SD rats (7 weeks old) were randomly divided into a control group, a model group, and a puerarin treatment group with high (H), moderate (M), and low (L) dosage. After streptozotocin induction, puerarin was applied via intragastric administration for 8 consecutive weeks with dosages of 0.25, 0. 5 and 1.0 mg/(kg·d) for L, M, and H groups, respectively. Fasting blood glucose (BG), creatinine (Scr), urea nitrogen (BUN), and urine albumin excretion rate (UAER) were measured, along with morphological observation of renal cells. The expression of intracellular adhesion molecule 1 (ICAM-1) and tumor necrosis factor α (TNF-α) was determined using immunohistochemical (IHC) staining, while renal cortex cell apoptosis was assayed by in situ end-labeling method. RESULTS: Model rats had significantly elevated levels of BG, Scr, BUN, and UAER compared to controls (p<0.05). All these increases were partially but significantly suppressed by puerarin (p<0.05), which also caused marked improvement of histopathological damages. Puerarin at each dosage significantly eliminated elevations of ICAM-1 and TNF-α levels in model rats (p<0.05), and decreased apoptotic indexes of renal cortex cells (p<0.05). CONCLUSIONS: Early-stage renal damages can be significantly improved by puerarin, possibly via its suppression of ICAM-1 and TNF-α expression in diabetic rat kidneys.