Knockdown of TRIM32 Protects Hippocampal Neurons from Oxygen-Glucose Deprivation-Induced Injury.

Tripartite motif 32 (TRIM32) is a member of TRIM family that plays a potential role in neural regeneration. However, the biological function of TRIM32 in cerebral ischemia reperfusion injury has not been investigated. In the present study, we evaluated the expression level of TRIM32 in hippocampal neurons following oxygen-glucose deprivation/reperfusion (OGD/R). The results showed that TRIM32 expression was significantly elevated in hippocampal neurons subjected to OGD/R as compared to the neurons cultured in the normoxia condition. To further evaluate the role of TRIM32, hippocampal neurons were transfected with TRIM32 small interfering RNA (si-TRIM32) to knock down TRIM32. We found that knockdown of TRIM32 improved cell viability of OGD/R-stimulated hippocampal neurons. Generation of reactive oxygen species was decreased, while contents of superoxide dismutase and glutathione peroxidase were increased after si-TRIM32 transfection. Knockdown of TRIM32 suppressed cell apoptosis, as proved by the increased bcl-2 expression along with decreased bax expression and caspase-3 activity. We also found that TRIM32 knockdown enhanced OGD/R-induced activation of Nrf2 signaling pathway in hippocampal neurons. Furthermore, siRNA-Nrf2 was transfected to knock down Nrf2. SiRNA-Nrf2 transfection reversed the protective effects of TRIM32 knockdown on neurons. These data suggested that knockdown of TRIM32 protected hippocampal neurons from OGD/R-induced oxidative injury through activating Nrf2 signaling pathway.

MicroRNA-770 affects proliferation and cell cycle transition by directly targeting CDK8 in glioma.

BACKGROUND: MicroRNAs play crucial roles in tumorigenesis and tumor progression. miR-770 has been reported to be downregulated in several cancers and affects cancer cell proliferation, apoptosis, metastasis and drug resistance. However, the role and underlying molecular mechanism of miR-770 in human glioma remain unknown and need to be further elucidated. METHODS: The expression of miR-770 in glioma tissues and cell lines was measured by quantitative real-time PCR (qRT-PCR) to explore the association of miR-770 expression with clinicopathological characteristics. The expression of CDK8 was detected by qRT-PCR and Western blotting in glioma tissues. A target prediction program and a dual-luciferase reporter assay were used to confirm that CDK8 is a target gene of miR-770. MTT and cell counting assays were used to assess the effect of miR-770 on glioma cell proliferation. The cell cycle distribution and apoptosis were examined by flow cytometry. CDK8 siRNA and overexpression were used to further confirm the function of the target gene. RESULTS: We demonstrated that miR-770 expression was downregulated in human glioma tissues and cell lines. The overexpression of miR-770 inhibited glioma cell proliferation and cell cycle G1-S transition and induced apoptosis. The inhibition of miR-770 facilitated cell proliferation and G1-S transition and suppressed apoptosis. miR-770 expression was inversely correlated with CDK8 expression in glioma tissues. CDK8 was confirmed to be a direct target of miR-770 by using a luciferase reporter assay. The overexpression of miR-770 decreased CDK8 expression at both the mRNA and protein levels, and the suppression of miR-770 increased CDK8 expression. Importantly, CDK8 silencing recapitulated the cellular and molecular effects observed upon miR-770 overexpression, and CDK8 overexpression eliminated the effects of miR-770 overexpression on glioma cells. Moreover, both exogenous expression of miR-770 and silencing of CDK8 resulted in suppression of the Wnt/ß-catenin signaling pathway. CONCLUSIONS: Our study demonstrates that miR-770 inhibits glioma cell proliferation and G1-S transition and induces apoptosis through suppression of the Wnt/ß-catenin signaling pathway by targeting CDK8. These findings suggest that miR-770 plays a significant role in glioma progression and serves as a potential therapeutic target for glioma.

PirB Overexpression Exacerbates Neuronal Apoptosis by Inhibiting TrkB and mTOR Phosphorylation After Oxygen and Glucose Deprivation Injury.

Previous studies have proven that paired immunoglobulin-like receptor B (PirB) plays a crucial suppressant role in neurite outgrowth and neuronal plasticity after central nervous system injury. However, the role of PirB in neuronal survival after cerebral ischemic injury and its mechanisms remains unclear. In the present study, the role of PirB is investigated in the survival and apoptosis of cerebral cortical neurons in cultured primary after oxygen and glucose deprivation (OGD)-induced injury. The results have shown that rebarbative PirB exacerbates early neuron apoptosis and survival. PirB gene silencing remarkably decreases early apoptosis and promotes neuronal survival after OGD. The expression of bcl-2 markedly increased and the expression of bax significantly decreased in PirB RNAi-treated neurons, as compared with the control- and control RNAi-treated ones. Further, phosphorylated TrkB and mTOR levels are significantly downregulated in the damaged neurons. However, the PirB silencing markedly upregulates phosphorylated TrkB and mTOR levels in the neurons after the OGD. Taken together, the overexpression of PirB inhibits the neuronal survival through increased neuron apoptosis. Importantly, the inhibition of the phosphorylation of TrkB and mTOR may be one of its mechanisms.

Inhibition of PirB Activity by TAT-PEP Improves Mouse Motor Ability and Cognitive Behavior.

Paired immunoglobulin-like receptor B (PirB), a functional receptor for myelin-associated inhibitory proteins, plays an important role in axon regeneration in injured brains. However, its role in normal brain function with age has not been previously investigated. Therefore in this study, we examined the expression level of PirB in the cerebral cortex, hippocampus and cerebellum of mice at 1 month, 3 months and 18 months of age. The results showed that the expression of PirB increased with age. We further demonstrated that overexpression of PirB inhibited neurite outgrowth in PC12 cells, and this inhibitory activity of PirB could be reversed by TAT-PEP, which is a recombinant soluble PirB ectodomain fused with TAT domain for blood-brain barrier penetration. In vivo study, intraperitoneal administration of TAT-PEP was capable of enhancing motor capacity and spatial learning and memory in mice, which appeared to be mediated through regulation of brain-derived neurotrophic factor (BDNF) secretion. Our study suggests that PirB is associated with aging and TAT-PEP may be a promising therapeutic agent for modulation of age-related motor and cognitive dysfunctions.

Parthenolide attenuates cerebral ischemia/reperfusion injury via Akt/GSK-3ß pathway in PC12 cells.

Parthenolide (PN), a sesquiterpene lactone isolated from the herbal medicine feverfew (Tanacetum parthenium), was reported to possess neuroprotective activity. However, the neuroprotective effect of PN against cerebral ischemia/reperfusion (I/R) injury remains unclear. Therefore, the aim of the present study was to explore the neuroprotective effects of PN against oxygen-glucose deprivation (OGD)-induced apoptosis in PC12 cells and the underlying mechanisms. Our results demonstrated that PN ameliorated OGD/R-evoked neuronal injury and oxidative stress in PC12 cells. In addition, PN notably decreased HIF-1α expression, as well as inhibited apoptosis in PC12 cells after OGD/R. Furthermore, PN pretreatment significantly enhanced the phosphorylation of Akt and GSK-3ß in PC12 cells exposed to OGD/R. In conclusion, the present study demonstrated that PN exhibits a neuroprotective effect against OGD/R through activation of the Akt/GSK-3ß signaling pathway. Our findings suggest that PN has the potential to serve as a novel therapeutic agent for cerebral I/R injury.

Clinical Observation of Modified Buzhong Yiqitang Combined with Erxian Decoction in Treatment of Stress Urinary Incontinence in Perimenopausal Women / 中国实验方剂学杂志

Objective:To observe the clinical efficacy of the modified Buzhong Yiqitang combined with Erxian decoction in treating stress urinary incontinence （SUI） of perimenopausal women due to spleen and kidney Qi deficiency. Method:One hundred and six patients were randomly divided into a control group （52 cases） and an observation group（54 cases）. Patients in both groups received lifestyle intervention and pelvic floor muscle training （PFMT）. On this basis， patients in the observation group were further treated with the modified Buzhong Yiqitang combined with Erxian decoction， 1 bag/day， while those in the control group were provided with Suoquan pills， 6 g/time， 2 times/day， for eight weeks. Following the international consultation on incontinence questionnaire-short form （ICIQ-SF） scoring before and after treatment， the urodynamic parameters such as maximum urinary flow rate （Q_max）， maximum urethral closure pressure （MUCP）， residual urine volume （RUV）， abdominal pressure leakage point pressure （ALPP）， and bladder capacity （BC） were measured. The number of incontinence episodes per 24 h， the degree of urinary incontinence， the amount of 1 h urine leakage， and the spleen and kidney Qi deficiency syndrome score were recorded before and after treatment. The levels of estradiol （E₂）， follicle stimulating hormone （FSH）， pituitary adenylate cyclase activating peptide （PACAP）， and vasoactive intestinal peptide （VIP） were measured before and after treatment. Result:The ICIQ-SF sub-scores of the urinary incontinence frequency， severity， and impact on quality of life as well as the total score in the observation group were all lower than those in the control group （<italic>P</italic><0.01）. Q_max， MUCP， ALPP and BC in the observation group were elevated in contrast to those in control group （<italic>P</italic><0.01）， while the RUV declined （<italic>P</italic><0.01）. Compared with the control group， the observation group exhibited a decreased number of incontinence episodes per 24 h， milder degree of urinary incontinence， reduced amount of 1 h urine leakage， and lower spleen and kidney Qi deficiency syndrome score （<italic>P</italic><0.01）. The E₂， PACAP， and VIP in the observation group were up-regulated as compared with those in the control group （<italic>P</italic><0.01）， whereas the FSH was down-regulated （<italic>P</italic><0.01）. The cure and effective rates of the observation group were （29/50） 58.00% and （47/50）94.00%， respectively， significantly better than （18/48）37.50% and （38/48）79.17% of the control group （<italic>χ</italic>²=4.124， <italic>χ</italic>²=4.683， <italic>P</italic><0.05）. Conclusion:On the basis of the lifestyle intervention and PFMT， the modified Buzhong Yiqitang combined with Erxian decoction obviously alleviates urinary incontinence， adjusts sex hormones， PACAP and VIP， ameliorates urodynamic parameters， and enhances the quality of life of patients with SUI due to spleen and kidney Qi deficiency. The resulting cure and effective rates are superior to those of the positive control.

MicroRNA-25 Negatively Regulates Cerebral Ischemia/Reperfusion Injury-Induced Cell Apoptosis Through Fas/FasL Pathway.

MicroRNA-25 (miR-25) has been reported to be a major miRNA marker in neural cells and is strongly expressed in ischemic brain tissues. However, the precise mechanism and effect of miR-25 in cerebral ischemia/reperfusion (I/R) injury needs further investigations. In the present study, the oxygen-glucose deprivation (OGD) model was constructed in human SH-SY5Y and IMR-32 cells to mimic I/R injury and to evaluate the role of miR-25 in regulating OGD/reperfusion (OGDR)-induced cell apoptosis. We found that miR-25 was downregulated in the OGDR model. Overexpression of miR-25 via miRNA-mimics transfection remarkably inhibited OGDR-induced cell apoptosis. Moreover, Fas was predicted as a target gene of miR-25 through bioinformatic analysis. The interaction between miR-25 and 3'-untranslated region (UTR) of Fas mRNA was confirmed by dual-luciferase reporter assay. Fas protein expression was downregulated by miR-25 overexpression in OGDR model. Subsequently, the small interfering RNA (siRNA)-mediated knockdown of Fas expression also inhibited cell apoptosis induced by OGDR model; in contrast, Fas overexpression abrogated the protective effects of miR-25 on OGDR-induced cells. Taken together, our results indicate that the upregulation of miR-25 inhibits cerebral I/R injury-induced apoptosis through downregulating Fas/FasL, which will provide a promising therapeutic target.

Vasoactive intestinal peptide protects against ischemic brain damage induced by focal cerebral ischemia in rats.

Vasoactive intestinal peptide (VIP) exerts neuroprotective effects under various neurotoxic conditions in vitro. In the present study, we investigated the effects of VIP on transient ischemic brain damage. Focal cerebral ischemia was induced using middle cerebral artery occlusion (MCAO) for 120 min in the adult rat brain. Either a single intracerebroventricular injection of VIP or saline was given at the beginning of reperfusion. Forty-eight hours after MCAO, the rats were sacrificed for evaluation of the infarct volume and histological analysis. ELISA was performed to assay levels of serum S100B before being sacrificed. We also evaluated the blood-brain barrier (BBB) permeability using Evans blue dye injection method. In contrast to the cases treated with vehicle, the infarct volume was significantly (P<0.05) reduced, and terminal deoxynucleotidyl transferase-mediated dUTP-nick end labeling (TUNEL) staining and immunoreactivity for S100B were also significantly (P<0.05) decreased in the ischemic hemisphere with VIP treatment. In addition, the elevations of serum S100B were significantly (P<0.01) attenuated in VIP-treated rats compared with those of control rats. Treatment with VIP did not result in a significant reduction of Evans blue leakage, although it tended to be lower than that in the control rats. Our data suggest that treatment with VIP reduces brain damage in ischemic rats, and this effect may be associated with the attenuation of apoptosis and S100B expression.

[Neuroprotective effects of vasoactive intestinal peptide against rat cerebral ischemia].

OBJECTIVE: To explore the neuroprotective effect of vasoactive intestinal peptide (VIP) in rat ischemic brain injury. METHODS: VIP was administered via intracerebroventricular injection in SD rats prior to focal cerebral ischemia by intraluminal occlusion of the middle cerebral artery. The infarct volume was assessed with TTC staining, and immunohistochemistry was performed to analyze the S100beta expression in the cerebral tissue, with the serum concentrations of S100beta detected by double-antibody sandwich enzyme-linked immunosorbent assay. RESULTS: After VIP injection, the relative infarct volume in the rats with cerebral ischemia was significantly reduced by 32.3% as compared with the volume in the control group on day 1 (P<0.05), and the number of S100beta-positive cells was significantly decreased in the cerebral tissue (P<0.05). The injection also resulted in significantly decreased serum S100beta concentrations in the rats (P<0.05). CONCLUSION: VIP injection can reduce the infarct volume in rats with focal cerebral ischemia, suggesting the neuroprotective effect of VIP in brain ischemia possibly by reducing S100beta overexpression.