cPKCγ Inhibits Caspase-9-Initiated Neuronal Apoptosis in an Ischemia Reperfusion Model In Vitro Through p38 MAPK-p90RSK-Bad Pathway.

Strokes are one of the leading causes of death and disability in the world. Previously we have found that conventional protein kinase Cγ (cPKCγ) plays neuroprotective role in ischemic strokes. Further, we found that cPKCγ knockdown increased the level of cleaved (cl)-Caspase-3. However, the precise mechanisms underlying cPKCγ-mediated neuronal death remain unclear. To this end, a model incorporating 1 h oxygen-glucose deprivation/24 h reoxygenation (1 h OGD/24 h R) was established in cortical neurons. We found that cPKCγ knockdown remarkably increased neuronal death after OGD. We also found that cPKCγ knockdown increased the level of cl-Caspase-3 through the upstream initiators Capsases-9 (not Caspase-8/12) in OGD-treated neurons. Overexpression of cPKCγ could decrease neuronal death and cl-Caspase-3 and -9 levels. Moreover, cPKCγ knockdown further reduced the phosphorylation levels of p38 MAPK, p90RSK, and Bad. In addition, the protein levels of Bcl-2 and Bcl-xl were decreased after cPKCγ knockdown, whereas that of Bax was increased. In conclusion, our results suggest that cPKCγ partly alleviates ischemic injury through activating the p38 MAPK-p90RSK-Bad pathway and inhibiting Caspase-9 initiated apoptosis. This may have potential as a therapeutic target for ischemic stroke.

miR-15a regulates oxygen glucose deprivation/reperfusion (OGD/R)-induced neuronal injury by targeting BDNF.

Multiple microRNAs (miRs) have also been implicated in ischemic brain injury. This research intended to probe the regulatory function and the mechanism of miR-15a on the ischemic brain injury induced by oxygen-glucose deprivation/reoxygenation (OGD/R) in neurons of rats. The OGD/R model was established with the cortical neurons separated from rats. After transfection with miR-15a mimic negative control (NC), miR-15a mimic, miR-15a inhibitor NC and miR-15a inhibitor, the OGD/R-induced apoptosis were detected. Using bioinformatic softwares including TargetScan, miRanda, and miRWalk to predict the underlying targets of miR-15a, and the binding of miR-15a with brain-derived neurotrophic factor (BDNF) were validated with double-fluorescein reporter assay system. The expression levels of BDNF mRNA and protein were detected with qRT-PCR and western blot. The effect of miR-15a on PI3K/AKT pathway in neurons submitted to OGD/R was also investigated. The findings showed that miR-15a may mediate the apoptosis of neurons submitted to OGD/R, and lower expression of Bcl-2 and higher expression of Bax and cleaved caspase-3 were observed. BDNF was screened as the candidate target, and the direct binding of miR-15a with 3'-UTR of BDNF were verified. Further research showed that miR-15a downregulated the expression of BDNF mRNA and protein, thus exerted negative regulatory effect on the OGD/R injury. PI3K/AKT pathway may be related to the regulatory effect of miR-15a. Our findings contribute to uncovering novel pathogenesis for ischemic brain injury.

[Neuroprotective effects of linagliptin on ischemia/reperfusion in mice].

Objective: To evaluate the neuroprotective effects of linagliptin, a dipeptidyl peptidase-4(DPP-4) inhibitor, on cerebral ischemia/reperfusion(I/R) injury in mice. Methods: BALB/c mice were randomly divided into Sham group, I/R group and linagliptin (2.5, 5 and 10 mg/kg) +I/R group, 8 mice in each group. The mice in the linagliptin group were administrated by gavage 3 weeks before I/R. I/R injury model was induced by MCAO, neurological deficit scores(n=8) and infarct volume(n=4) were assessed 24 h following reperfusion. Forty-eight hours following reperfusion, mice were euthanized, the contents of glutathione (GSH), malondialdehyde (MDA), phosphoinositide 3 kinase (PI3K), phosphoprotein kinase B (p-Akt) and rapamycin target protein (mTOR) in brain tissue were measured (n=4). Results: Compared with the I/R group, the neurological deficit score and infarct volume were significantly decreased in the linagliptin pretreatment group after 24 h reperfusion (P＜0.05); the MDA content in the brain was significantly decreased (P＜0.05), while the GSH, PI3K, p-Akt and mTOR levels were significantly increased (P＜0.05). Conclusion: This study proves that linagliptin exerted a neuroprotective effect in I/R mice, which may be mediated by activation of the PI3K/AKT/mTOR pathway.

Synthesis of polyethyleneimine capped carbon dots for preconcentration and slurry sampling analysis of trace chromium in environmental water samples.

Carbon dots capped with polyethyleneimine (CD-PEI) were synthesized and applied in selective separation and preconcentration of trace Cr(VI). Dispersed particle extraction (DPE) slurry sampling with flame atomic absorption spectrometry (FAAS) was used to selectively and sensitively determine Cr(VI) in water samples. The as-synthesized CD-PEI was confirmed by Fourier transform infrared spectroscopy, high-resolution transmission electron microscopy, elemental analysis, fluorescence and zeta potential measurement. The adsorption of Cr(VI) on CD-PEI was evaluated. Its isothermal adsorption was studied and fitted in the Langmuir model. Nearly 85% of Cr(VI) was adsorbed within 10 min showed that the CD-PEI exhibited fairly fast kinetics for the sorption of Cr(VI). Experimental conditions, including the content and size of CD-PEI, sample pH, adsorption time, sample volume, slurry volume and interfering ions, were further optimized to obtain efficient preconcentration and high-precision determination of Cr(VI). CD-PEI with small size turned to be a good candidate for the preparation of slurry. CD-PEI served not only as a promising adsorbent for separation and preconcentration of Cr, but also a signal-enhancing agent in FAAS. The method achieved an enhancement factor of 30 and a detection limit (S/N=3) of 0.21 µg L(-1) Cr(VI) with a consumption of 14.0 mL sample and an adsorption time of 5 min, which provided two times of signal enhancement. The RSD for 11 replicate measurements of 5.0 µg L(-1) Cr(VI) was 2.8%. The possible signal enhancement mechanism was proposed. The developed method has been applied to determine trace Cr(VI) in a variety of water samples.

[Correlation analysis between the PM2.5, PM10 which were taken in the hazy day and the number of outpatient about breathing sections, breathing sections of pediatrics in Shanghai].

In order to explore the correlation between the concentration of PM10, PM2.5 which were taken during the day of haze pollution and the average number of outpatient service, pediatrics. Based on the date with the number of pediatric outpatient and the concentration of PM2.5, PM10 which were taken form the haze days on 1 January 2009 - December 31 in 6 hospital in shanghai such as xinhuan hospital, we analyzed the data and executed the risk evaluation. The results showed that: in the haze day, when the average concentration of PM10 increase 50 microg/m3, the average number of the outpatient service and pediatric clinic increased 3% and 0.5%, when the average concentration of PM2.5 increase 34 microg/m3, the average number of the outpatient service and pediatric clinic increased 1.9% and 3.2%, Also, the pollution of PM10 and PM2.5 has a larger cumulative effects on the number of outpatient service. And the accumulation effect will be To maximize after 6 days behind the haze pollution. Thus, PM2.5, PM10 which were taken during the haze of pollution in shanghai, has certain influence on the average number of outpatient service, pediatric clinic.