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Background: Inflammation and oxidative stress play important roles in energy imbalance and its complications. Recent research indicates that hypothalamic inflammation may contribute to the pathogenesis of metabolic syndrome and cardiac dysfunction, but the mechanisms remain unclear. We hypothesized that suppression of the proinflammatory IKKβ/NF-κB pathway in the hypothalamus can improve energy balance and cardiac function in type 2 diabetic (T2D) rats. Methods: Normal and T2D rats received bilateral hypothalamic arcuate nucleus (ARC) infusions of the IKKβ inhibitor SC-514 or vehicle via osmotic minipump. Metabolic phenotyping, immunohistochemical analyses, and biochemical analyses were used to investigate the outcomes of inhibition of the hypothalamic IKKβ. Echocardiography and glucometer were used for measuring cardiac function and blood glucose, respectively. Blood samples were collected for the evaluation of circulating proinflammatory cytokines. Heart was harvested for cardiac morphology evaluations. The ARC was harvested and analyzed for IKKβ, NF-κB, proinflammatory cytokines, reactive oxygen species (ROS), and NAD(P)H (gp91phox, p47phox) oxidase activity levels and neuropeptides. Results: Compared with normal rats, T2D rats were characterized by hyperglycemia, hyperinsulinemia, glucose intolerance, cardiac dysfunction, as well as higher ARC levels of IKKβ, NF-κB, proinflammatory cytokines, ROS, gp91phox, and p47phox. ARC infusion of the IKKβ inhibitor SC-514 attenuated all these changes in T2D rats, but not in normal rats. Conclusions: Our results indicate that the hypothalamic IKKβ/NF-κB pathway plays a key role in modulating energy imbalance and cardiac dysfunction, suggesting its potential therapeutic role during type 2 diabetes mellitus. [ABSTRACT FROM AUTHOR]

Objective: This study explored the protective effects of the microRNA-126 (miR-126)- mediated PI3K/Akt/eNOS signaling pathway on human cardiac microvascular endothelial cells (HCMECs) against hypoxia/reoxygenation (H/R)-induced injury and the inflammatory response. Methods: Untreated HCMECs were selected for the control group. After H/R treatment and cell transfection, the HCMECs were assigned to the H/R, miR-126 mimic, mimicnegative control (NC), miR-126 inhibitor, inhibitor-NC, wortmannin (an inhibitor of PI3K) and miR-126 mimic + wortmannin groups. Super oxide dismutase (SOD), nitric oxide (NO), vascular endothelial growth factor (VEGF) and reactive oxygen species (ROS) were measured utilizing commercial kits. Quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) were performed to detect miR-126 expression and the mRNA and protein expression of inflammatory factors. Western blotting was used to determine the expression of key members in the PI3K/Akt/eNOS signaling pathway. ACCK- 8 assay and flow cytometry were employed to examine cell proliferation and apoptosis, respectively. The angiogenic ability in each group was detected by the lumen formation test. Results: Compared to the control group, p/t-PI3K, p/t-Akt and p/t-eNOS expression, NO, VEGF and SOD levels, cell proliferation and in vitro lumen formation ability were decreased, while the ROS content, interleukin (IL)-6, IL-10 and tumor necrosis factor (TNF)-α expression and cell apoptosis were significantly increased in the H/R, mimic-NC, miR-126 inhibitor, inhibitor- NC, wortmannin and miR-126 mimic + wortmannin groups. Additionally, in comparison with the H/R group, the miR-126 mimic group had elevated p/t-PI3K, p/t-Akt and p/t-eNOS expression, increased NO, VEGF and SOD contents, and strengthened cell proliferation and lumen formation abilities but also exhibited decreased ROS content, reduced IL-6, IL-10 and TNF-α expressions, and weakened cell apoptosis, while the miR-126 inhibitor and wortmannin group exhibited the opposite results. Furthermore, decreased p/t-PI3K, p/t-Akt and p/t-eNOS expressions, decreased NO, VEGF and SOD contents, cell proliferation and lumen formation abilities, as well as increased ROS content, increased IL-6, IL-10 and TNF-α expression, and increased cell apoptosis were observed in the miR-126 mimic + wortmannin group compared to themiR-126 mimic group. Conclusions: These findings indicated that miR-126 protects HCMECs from H/R-induced injury and inflammatory response by activating the PI3K/Akt/ eNOS signaling pathway. [ABSTRACT FROM AUTHOR]