The cytoprotective role of omentin against oxidative stress-induced PC12 apoptosis.

Oxidative stress has been proven to play a critical role in the pathogenesis of neuronal injury. As a novel adipocytokine, omentin is produced by visceral adipose with insulin sensitizing effects and has been revealed to possess anti-inflammatory effects. However, the possible effect of omentin on oxidative stress remains unknown. The present study aimed to detect the potential protective effect of omentin against hydrogen peroxide (H2O2)-induced cytotoxicity of PC12 cells. The results showed that no cytotoxic effect was shown in PC12 cells co-cultured with omentin alone at a concentration of 50-1000 ng/mL. The CCK8 and TUNEL assays suggested that omentin could remarkably attenuate apoptosis induced by 100 µM H2O2. The PCR and western blotting showed that the expression levels of Bax was significantly inhibited by omentin via the upregulation of miR-128-3p at its 3'-UTR. Taken together, these results indicated that omentin protects PC12 cells against H2O2-induced apoptosis, and further studies need to be conducted before utilization in the clinic for the treatment of neurodegenerative diseases.

Reducing Suppressors of Cytokine Signaling-3 (SOCS3) Expression Promotes M2 Macrophage Polarization and Functional Recovery After Intracerebral Hemorrhage.

Intracerebral hemorrhage (ICH) is a fatal subtype of stroke, and effective interventions to improve the functional outcomes are still lacking. Suppressor of cytokine signaling 3 (SOCS3) plays critical roles in the inflammatory response by negatively regulating cytokine-Jak-Stat signaling. However, the role of SOCS3 in the regulation of macrophage polarization is highly controversial and the fine regulation exerted by SOCS3 needs further understanding. In this study, rat ICH models were established by infusion of collagenase into the caudate nucleus. To decrease SOCS3 expression into microglia/macrophages in the hemorrhagic lesion area, we injected lentiviral short hairpin RNA (shSOCS3) (Lenti-shSOCS3) into the hematoma cavity at 24 h following ICH. We found that the number of iNOS-positive cells (M1 phenotype) was significantly reduced, whereas arginase-1-positive cells (M2 phenotype) were markedly elevated in animals that received Lenti-shSOCS3 injections compared with those in the Lenti-EGFP and saline groups. The increase in arginase-1-positive cells was associated with a significantly lower pro-inflammatory microenvironment, which included the downregulation of pro-inflammatory cytokines [interleukin (IL)-1ß, IL-6, and TNF-α] and concurrent upregulation of anti-inflammatory (IL-10) mediators. In addition, this marked shift toward the M2 phenotype was associated with suppressed NF-κB activation. Furthermore, these changes notably enhanced the neuroprotective effects and functional recovery in Lenti-shSOCS3-injected animals. Our findings indicated that reduction in SOCS3 expression caused a marked bias toward the M2 phenotype and ameliorated the inflammatory microenvironment, which enhanced neuroprotective effects and resulted in notable improvement in functional recovery after ICH.

Down-regulation of 14-3-3ß exerts anti-cancer effects through inducing ER stress in human glioma U87 cells: Involvement of CHOP-Wnt pathway.

We previously identified 14-3-3ß as a tumor-specific isoform of 14-3-3 protein in astrocytoma, but its functional role in glioma cells and underlying mechanisms are poorly understood. In the present study, we investigated the effects of 14-3-3ß inhibition in human glioma U87 cells using specific targeted small interfering RNA (siRNA). The results showed that 14-3-3ß is highly expressed in U87 cells but not in normal astrocyte SVGp12 cells. Knockdown of 14-3-3ß by Si-14-3-3ß transfection significantly decreased the cell viability but increased the LDH release in a time-dependent fashion in U87 cells, and these effects were accompanied with G0/G1 cell cycle arrest and apoptosis. In addition, 14-3-3ß knockdown induced ER stress in U87 cells, as evidenced by ER calcium release, increased expression of XBP1S mRNA and induction of ER related pro-apoptotic factors. Down-regulation of 14-3-3ß significantly decreased the nuclear localization of ß-catenin and inhibited Topflash activity, which was shown to be reversely correlated with CHOP. Furthermore, Si-CHOP and sFRP were used to inhibit CHOP and Wnt, respectively. The results showed that the anti-cancer effects of 14-3-3ß knockdown in U87 cells were mediated by increased expression of CHOP and followed inhibition of Wnt/ß-catenin pathway. In summary, the remarkable efficiency of 14-3-3ß knockdown to induce apoptotic cell death in U87 cells may find therapeutic application for the treatment of glioma patients.

Dynamin-related protein 1 inhibitors protect against ischemic toxicity through attenuating mitochondrial Ca2+ uptake from endoplasmic reticulum store in PC12 cells.

Intracellular calcium homeostasis disorder and mitochondrial dysfunction are involved in many acute and chronic brain diseases, including ischemic brain injury. An imbalance in mitochondrial fission and fusion is one of the most important structural abnormalities found in a large number of mitochondrial dysfunction related diseases. Here, we investigated the effects of mitochondrial division inhibitor A (mdivi A) and mdivi B, two small molecule inhibitors of mitochondrial fission protein dunamin-related protein 1 (Drp-1), in neuronal injury induced by oxygen-glucose deprivation (OGD) in PC12 cells. We found that mdivi A and mdivi B inhibited OGD-induced neuronal injury through attenuating apoptotic cell death. These two inhibitors also preserved mitochondrial function, as evidenced by reduced reactive oxygen species (ROS) generation and cytochrome c release, as well as prevented loss of mitochondrial membrane potential (MMP). Moreover, mdivi A and mdivi B significantly suppressed mitochondrial Ca(2+) uptake, but had no effect on cytoplasmic Ca(2+) after OGD injury. The results of calcium imaging and immunofluorescence staining showed that Drp-1 inhibitors attenuated endoplasmic reticulum (ER) Ca(2+) release and prevented ER morphological changes induced by OGD. These results demonstrate that Drp-1 inhibitors protect against ischemic neuronal injury through inhibiting mitochondrial Ca(2+) uptake from the ER store and attenuating mitochondrial dysfunction.

[A cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy pedigree: clinical pathology, neuroimaging and molecular genetics studies].

OBJECTIVE: To explore the clinical presentations, pathological features, imaging manifestation and genetic mutation of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). METHODS: A systematic study on the clinical manifestations, neuroimaging characteristics, pathology and molecular genetics was performed in the proband and 16 members of the family. An investigation on the hereditary pattern of the family tree of the proband was also conducted. RESULTS: The main clinical features including history of ischemic stroke attack, migraine, psychological disoders and dementia were noted. No risk factors of hypertension and arteriosclerosis were found. Pedigree maps of the index case were consistent with classical autosomal dominant inheritance. Subcortical multi-infarct lesions, leukoencephalopathy, O'Sullivan sign and "Herringbone pattern"shape sign were observed via cranial MRI analysis. By electron microscopy, skin biopsy indicated the characteristic deposition of granular osmiophilic material (GOM) on the basement of smooth muscle cells of arterioles in the proband. The mutation of C144Y in the fourth exon of notch 3 gene was revealed in three cases, including 1 patient with normal MRI. CONCLUSION: The pedigree is diagnosed with CADASIL. The main cause can be attributed to a mutation of C144Y in the fourth exon of Notch 3 gene. The pedigree has enriched Chinese database of CADASIL.

Protective effects and mechanism of puerarin on learning-memory disorder after global cerebral ischemia-reperfusion injury in rats.

OBJECTIVE: To observe the effect of puerarin on the learning-memory disorder after global cerebral ischemia-reperfusion injury in rats, and to explore its mechanism of action. METHODS: The global cerebral ischemia-reperfusion injury model was established using the modifified Pulsinelli four-vessel occlusion in Sprague-Dawley rats. Rats were intraperitoneally injected with puerarin (100 mg/kg) 1 h before ischemia and once every 6 h afterwards. The learning-memory ability was evaluated by the passive avoidance test. The dynamic changes of the cell counts of apoptosis and positive expression of Bcl-2 in the hippocampus CA1 region were determined by the TUNEL and immunohistochemical methods, respectively. RESULTS: (1) Compared with the reperfusion group, the step through latency (STL) in the passive avoidance test in the puerarin group was prolonged signifificantly (P<0.01). (2) The apoptotic neurons were injured most severely on the 3rd day in the hippocampal CA1 region after global ischemia and reperfusion. In the puerarin group, the number of apoptotic cells decreased at respective time points after ischemia-reperfusion (P<0.01). (3) The level of positive expression of Bcl-2 varied according to the duration of reperfusion and the peak level occurred on day 1 in the hippocampal CA1 region after global cerebral ischemia. Compared with the reperfusion group, the expression of Bcl-2 in the puerarin group was up-regulated at the respective time points after ischemia reperfusion (P<0.01), reaching the peak on day 1. CONCLUSIONS: Puerarin could improve the learning-memory ability after global cerebral ischemia and reperfusion in rats. The protective mechanism might be related to the effect of inhibiting or delaying the cell apoptosis through up-regulating the expression of Bcl-2 after ischemia and reperfusion.