Oligomeric Aß25-35 induces the tyrosine phosphorylation of PSD-95 by SrcPTKs in rat hippocampal CA1 subfield.

PURPOSE: Although amyloid-ß (Aß) is one of the neuropathological hallmarks of Alzheimer's Disease (AD), the mechanisms of Aß neurotoxicity remain to be clarified. This study was aimed to evaluate the effect of Aß on postsynaptic density-95 (PSD-95) tyrosine phosphorylation. Elucidating the regulatory mechanisms underlying it may be a promising therapy in AD. METHODS: Aß25-35 oligomers (20 µg/rat) were administered intracerebroventricularly in adult male Sprague-Dawley rats. PSD-95 tyrosine phosphorylation was assessed using immunoprecipitation followed by immunoblot analysis. Immunoblot was applied for measuring the protein levels of PSD-95 and ß-actin. RESULTS: Following 3, 7, 14, 21 days after oligomeric Aß25-35 treatment, the tyrosine phosphorylation of PSD-95 increased significantly, and peaked at 3 days after oligomeric Aß25-35 treatment in hippocampal CA1 subfield. Src family protein tyrosine kinases (SrcPTKs) specific inhibitor PP2 attenuated the tyrosine phosphorylation of PSD-95 induced by Aß25-35. Amantadine [N-methyl-D-aspartate (NMDA) receptor noncompetitive antagonist], NVP-AAM077 (GluN2A-containing NMDA receptor selective inhibitor) and Ro25-6981 (GluN2B-containing NMDA receptor selective inhibitor) also suppressed the Aß25-35-induced PSD-95 tyrosine phosphorylation. CONCLUSION: These results suggest that Aß oligomers induce the tyrosine phosphorylation of PSD-95 by SrcPTKs, which is mediated by the activation of GluN2A- and GluN2B-containing NMDA receptors.

MiR-140-5p exerts a protective function in pregnancy-induced hypertension via mediating TGF-ß/Smad signaling pathway.

Animal experiments showed that PIH rats had increased mean arterial pressure (MAP), systolic blood pressure (SBP), and diastolic blood pressure (DBP), but decreased litter size, number of viable fetuses, fetal weight, and placental weight. The higher Flt-1 and lower VEGF was observed in PIH rats with elevated TNF-α and IL-6 levels and decreased IL-10 levels. Treatment with agomiR-140-5p improved regarding the above indicators. Cell experiments demonstrated that miR-140-5p mimic increased cell invasion and migration abilities and decreased the activity of TGF-ß/Smad pathway, while TGFBR1 can reverse the role of miR-140-5p mimic in trophoblasts.

The diagnostic value and regulatory mechanism of miR-200a targeting ZEB1 in pregnancy-induced hypertension.

OBJECTIVE: To investigate the diagnostic value and regulatory mechanism of miR-200a targeting ZEB1 in pregnancy-induced hypertension (PIH). METHODS: The expression of miR-200a and ZEB1 was detected in the placenta of PIH patients, and then the human trophoblastic cell line JEG-3 was transfected and divided into different groups: control group, NC group, ZEB1 siRNA group, miR-200a inhibitor group and miR-200a inhibitor group + ZEB1 siRNA group. After transfection, cell proliferation and migration/invasion were evaluated byMTT and Transwell assays, respectively, whereas apoptosis was assessed byflow cytometry. MiR-200a was measured by qRT-PCR, while ZEB1 was detectedby Western blotting. RESULTS: The expression of miR-200a was gradually increased in the placenta of patients with hypertension and mild or severe preeclampsia, while the mRNA and protein levels of ZEB1 were downregulated. A dual-luciferase reporter assay was performed to confirm the targeting relationship between miR-200a andZEB1.Compared to the control, the miR-200a inhibitor caused a strongdecrease in miR-200a andan upregulation of ZEB1, with a significant enhancement ofcell proliferation, migration and invasion and a decrease in apoptosis. However, no significant alteration was observedin the miR-200a level after administration of ZEB1 siRNA, while ZEB1 was downregulated, with significant suppression of growth. CONCLUSION: MiR-200a was upregulated in PIH patients, andinhibition of miR-200a may improve disease progression, as it could facilitatetrophoblastproliferation, migration and invasionandinhibitapoptosisby targeting ZEB1.

Current Trends for ST-segment Elevation Myocardial Infarction during the Past 5 Years in Rural Areas of China's Liaoning Province: A Multicenter Study.

BACKGROUND: Since 2010, two versions of National Guidelines aimed at promoting the management of ST-segment elevation myocardial infarction (STEMI) have been formulated by the Chinese Society of Cardiology. However, little is known about the changes in clinical characteristics, management, and in-hospital outcomes in rural areas. METHODS: In the present multicenter, cross-sectional study, participants were enrolled from rural hospitals located in Liaoning province in Northeast China, during two different periods (from June 2009 to June 2010 and from January 2015 to December 2015). Data collection was conducted using a standardized questionnaire. In total, 607 and 637 STEMI patients were recruited in the 2010 and 2015 cohorts, respectively. RESULTS: STEMI patients in rural hospitals were older in the second group (63 years vs. 65 years, P = 0.039). We found increases in the prevalence of hypertension, prior percutaneous coronary intervention (PCI), and prior stroke. Over the past 5 years, the cost during hospitalization almost doubled. The proportion of STEMI patients who underwent emergency reperfusion had significantly increased from 42.34% to 54.47% (P < 0.0001). Concurrently, the proportion of primary PCI increased from 3.62% to 10.52% (P < 0.0001). The past 5 years have also seen marked increases in the use of guideline-recommended drugs and clinical examinations. However, in-hospital mortality and major adverse cardiac events did not significantly change over time (13.01% vs. 10.20%, P = 0.121; 13.34% vs. 13.66%, P = 0.872). CONCLUSIONS: Despite the great progress that has been made in guideline-recommended therapies, in-hospital outcomes among rural STEMI patients have not significantly improved. Therefore, there is still substantial room for improvement in the quality of care.

Involvement of P38MAPK activation by NMDA receptors and non-NMDA receptors in amyloid-ß peptide-induced neuronal loss in rat hippocampal CA1 and CA3 subfields.

Oligomeric amyloid-ß peptide (Aß) has been found to be associated with the pathogenesis of Alzheimer's disease (AD). Numerous studies have reported Aß neurotoxicity, but the underlying molecular mechanisms remain to be fully illuminated. In the present study, we investigated the Aß-induced activation and regulation of P38MAPKs in rat hippocampus in vivo. The results showed that intracerebroventricular injection of oligomeric Aß25-35 increased the activation (phosphorylation) of P38MAPKs, and the level of cleaved caspase-3, but decreased the number of neurons in rat hippocampal CA1 and CA3 subfields. Downregulation of P38MAPK activity by SB239063 protected against the Aß neurotoxicity. Pretreatment with NMDA and non-NMDA receptor antagonists respectively suppressed P38MAPK activation induced by Aß25-35 oligomers and presented neuroprotective effect. Taken together, these data suggest that P38MAPK activation via NMDA and non-NMDA receptors is a key signal cascade in Aß-induced neuronal death. Inhibition of P38MAPK cascades may be a promising treatment in AD.

Oligomerized Abeta25-35 induces increased tyrosine phosphorylation of NMDA receptor subunit 2A in rat hippocampal CA1 subfield.

Amyloid-beta peptide (Abeta) plays a causal role in the pathogenesis of Alzheimer's disease (AD). To elucidate the mechanisms underlying the over-activation of NMDA receptors in AD, we investigated the alteration of NR2A tyrosine phosphorylation after intracerebroventricular infusion of Abeta25-35 oligomers. Abeta25-35 treatment resulted in the elevated tyrosine phosphorylation of NR2A in rat hippocampal CA1 subfield and facilitated the interactions of NR2A or PSD-95 with Src kinases. PP2, a specific inhibitor of Src family protein tyrosine kinases (SrcPTKs), not only attenuated the Abeta25-35-induced increases in the tyrosine phosphorylation of NR2A and in the associations among Src, NR2A, and PSD-95, but also protected against neuronal loss in the CA1 region. Preapplication of a noncompetitive NMDA receptor antagonist amantadine, an NR2A-selective NMDA receptor antagonist NVP-AAM077, or an NR2B-selective NMDA receptor antagonist Ro25-6981 inhibited the increased tyrosine phosphorylation of NR2A and prevented the associations among Src, NR2A, and PSD-95, but Ro25-6981 had less contribution. These results suggest that the activation of NMDA receptors after Abeta treatment promotes the formation of NR2A-PSD-95-Src complex and thus increases the tyrosine phosphorylation of NR2A by Src kinases, which up-regulates the function of NMDA receptors. Such positive feedback mediates the Abeta-induced over-activation of NMDA receptors and is involved in neuronal impairment.

Mitochondrial Ca2+ flux and respiratory enzyme activity decline are early events in cardiomyocyte response to H2O2.

Oxidative stress is involved in mitochondrial apoptosis, and plays a critical role in ischemic heart disease and cardiac failure. Exposure of cardiomyocytes to H(2)O(2) leads to oxidative stress and mitochondrial dysfunction. In this study, we investigated the temporal order of mitochondrial-related events in the neonatal rat cardiomyocyte response to H(2)O(2) treatment. At times ranging from 10 to 90 min after H(2)O(2) treatment, levels were determined for respiratory complexes I, II, IV and V, and citrate synthase activities, mitochondrial Ca(2+) flux, intracellular oxidation, mitochondrial membrane potential and apoptotic progression. Complexes II and IV activity levels were significantly reduced within 20 min of H(2)O(2) exposure while complexes I and V, and citrate synthase were unaffected. Mitochondrial membrane potential declined after 20 and 60 min of H(2)O(2) exposure while intracellular oxidation, declining complex I activity and apoptotic progression were detectable only after 60 min. Measurement of mitochondrial Ca(2+) ([Ca(2+)](m)) using rhodamine 2 detected an early accumulation of [Ca(2+)](m) occurring between 5 and 10 min. Pretreatment of cardiomyocytes with either ruthenium red or cyclosporin A abrogated the H(2)O(2)-induced decline in complexes II and IV activities, indicating that [Ca(2+)](m) flux and onset of mitochondrial permeability transition pore opening likely precede the observed early enzymatic decline. Our findings suggest that [Ca(2+)](m) flux represents an early pivotal event in H(2)O(2)-induced cardiomyocyte damage, preceding and presumably leading to reduced mitochondrial respiratory activity levels followed by accumulation of intracellular oxidation, mitochondrial membrane depolarization and apoptotic progression concomitant with declining complex I activity.