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Introduction Diabetic patients are often accompanied by complications of diabetic vascular disease, which could lead to heart failure or stroke. In this work, we explored the role of miR-503/Apelin-12 in diabetic angiopathy (DA) in vitro. Methods ELISA and qPCR were applied to assess the expression of miR-503 and Apelin-12 in high glucose (HG)-treated microvascular endothelial cells (HMEC-1). The effects of miR-503 on apoptosis, inflammation and oxidative stress were assessed by flow cytometry, western blotting, qPCR, and ELISA. The interaction between miR-503 and Apelin-12 was evaluated by dual-luciferase reporter assay, qPCR and ELISA, respectively. Western blotting was performed to examine the function of miR-503/Apelin-12 on JNK and p38MAPK activation. Results MiR-503 was markedly increased and Apelin-12 was decreased in HG-treated HMEC-1 cells. MiR-503 inhibitor significantly assuaged apoptosis, inflammation and oxidative stress in HMEC-1 cells. MiR-503 could specifically bind to the 3′UTR of Apelin and inversely downregulate Apelin-12 expression. Furthermore, Apelin-12 suppressed apoptosis, inflammation and oxidative stress. Inhibition of Apelin-12 could partially reverse the decrease of p-JNK and p-p38 expression levels induced by miR-503 suppression. Conclusion In HG-induced microvascular cells injury, miR-503/Apelin-12 enhances inflammation and oxidative stress by regulating JNK and p38MAPK pathway, suggesting a potential therapeutic target for DA.

Previous studies have demonstrated that pioglitazone (Piog), a peroxisome proliferator-activated receptor gamma (PPARγ) agonist, inhibits ischemia-induced brain injury. Piog has also been shown to exert anti-inflammatory effects by attenuation of nuclear factor-κB (NF-κB) activation after myocardial ischemia/reperfusion injury. Because NF-κB is known to play a major role in the pathophysiology of brain ischemia, the present study was undertaken to elucidate whether pioglitazone attenuates ischemic neuronal damage through PPARγ-mediated suppression of NF-κB apoptotic signaling pathway. Permanent middle cerebral artery occlusion (pMCAO) model was induced by using an intraluminal filament technique in rats. Piog was administrated i.p. twice (24 h before and at the time of ischemia insult) or once (10 min after ischemia). The neuroprotection of Piog was analyzed by assessing neurological deficits, infarction volume and morphological changes. The inhibition of NF-κB signaling pathway by Piog was evaluated by detecting the nuclear translocation of NF-κB p65 with immunohistochemistry and its target gene p53 by real-time PCR, and the expression of phospholated NF-κB p65 (p- NF-κB p65) in primary cultured neurons and the protein levels of IκBα and p-ERK in the ischemic cortex or striatum with Western blotting analysis. The contribution of a PPARγ mechanism to Piog's inhibitory effects on NF-κB and neuroprotection was evaluated by pretreatment with the PPARγ irreversible antagonist GW9662. In vitro ischemia in cultured primary neurons was induced by the oxygen-glucose deprivation (OGD) and the protective effect of Piog on cultured neurons was measured by lactate dehydrogenase (LDH) assay. Piog (0.5, 1, 2 mg/kg) reduced infarction volume, and improved morphological changes and motor deficits. Piog markedly up-regulated the protein levels of IκBα or p-ERK 6 h or 12 h after ischemia. Piog reduced the nuclear translocation of NF-κB p65 in the ischemic cortical cells and repressed the expression of p53 12 h after ischemia. Pre-treatment with GW9662 blocked Piog-elicited reduction in infarction volume, the increase in protein levels of IκBα and p-ERK, the reduction in the nuclear translocation of NF-κB subunit p65 and the repression of p53 mRNA expression. In addition, Piog attenuated the OGD-induced neuronal damage and inhibited the OGD-induced increases in p- NF-κB p65 in neurons. The present findings suggest that Piog's neuroprotection appears to be associated with PPARγ-mediated suppression of NF-κB signaling pathway.

MicroRNAs (miRNAs) involve in the regulation of a wide range of physiological processes. Recent studies suggested that miRNAs might play a role in osteoclast differentiation. Here, we identify a new miRNA (miR-9718) in primary mouse osteoclasts that promotes osteoclast differentiation by repressing protein inhibitor of activated STAT3 (PIAS3) at the post-transcriptional level. MiR-9718 was found to be transcribed during osteoclastogenesis, which was induced by macrophage colony stimulating factor (M-CSF) and receptor activator of nuclear factor-κB ligand (RANKL). Overexpression of miR-9718 in RAW 264.7 cells promoted M-CSF and RANKL-induced osteoclastogenesis, whereas inhibition of miR-9718 attenuated it. PIAS3 was predicted to be a target of miR-9718. Luciferase reporter gene validated the prediction. Transfection of pre-miR-9718 in RAW 264.7 cells induced by both M-CSF and RANKL inhibited expression of PIAS3 protein, while the mRNA levels of PIAS3 were not attenuated. In vivo, our study showed that silencing of miR-9718 using a specific antagomir inhibited bone resorption and increased bone mass in mice receiving ovariectomy (OVX) and in sham-operated control mice. Thus, our study showed that miR-9718 played an important role in osteoclast differentiation via targeting PIAS3 both in vitro and in vivo.

Background and purpose: We have previously reported that Ginkgolids which contain Ginkgolids A and B (Ginkgolids (A + B), GKAB) reduce infarct size in a rat model of focal ischemia. NF-κB-inducing kinase (NIK)–IκBα kinase (IKK) pathway plays an important role in activation of nuclear factor kappaB (NF-κB). A previous study demonstrated that Ginkgolid B inhibited lipopolysaccharide (LPS)- and platelet activating factor (PAF)-induced NF-κB activation in rat pleural polymorphonuclear granulocytes. However, little is known about the inhibitory mechanisms of Ginkgolids on the activation of NF-κB. The present study evaluated the effects of GKAB on NIK/IKK/IκB/NF-κB signaling pathway in a rat model of permanent focal cerebral ischemia. Methods: Rats were subjected to permanent middle cerebral artery occlusion (pMCAO) by intraluminal suture blockade. GKAB was injected intravenously (iv) immediately after ischemic onset. Western blot analysis was employed to determine alterations in IκBα, phosphorylated NIK (p-NIK) and phosphorylated IKKα (p-IKKα). Immunohistochemistry was used to confirm the nuclear translocation of NF-κB p65. RT-PCR was used to detect induction of NF-κB target gene c-Myc mRNA. Results: The results showed a brief increase in p-NIK levels after ischemia. GKAB blocked ischemia-induced increases in p-NIK and p-IKKα levels, and reversed the decline in IκBα levels. Ischemia-induced nuclear translocation of NF-κB p65 was attenuated by GKAB. GKAB also repressed the ischemia-induced increase in expression of NF-κB target gene c-Myc mRNA. Conclusions: These findings suggest that GKAB-mediated neuroprotective effect against ischemia appears to be associated with blocking NF-κB activation by suppressing the NIK–IKK pathway.