Effects of carbamazepine on the P-gp and CYP3A expression correlated with PXR or NF-κB activity in the bEnd.3 cells.

Drug-resistant epilepsy (DRE) is present in 20-30% of all patients who develop epilepsy. Growing evidences demonstrated that glutamate released during seizures to increase the brain P-glycoprotein (P-gp) expression. Carbamazepine (CBZ) is known to influence the P-gp and cytochrome P450 (CYP) expression. However, the exact molecular mechanism is still unknown. We investigated that the effects of NF-κB and pregnane X receptor (PXR) activity on P-gp and CYP3A expression in mouse brain endothelial (bEnd.3) cells treated with l-glutamate (mimicking the seizure conditions), CBZ (mimicking the AED treating conditions) or both (l-glutamate plus CBZ) through qPCR and Western blotting assay. Mean fluorescence intensity was used to observe P-gp efflux function by analysis of intracellular Rhodamine123 (Rho123) accumulation. P-gp, CYP3A, PXR and NF-κB p65 were elevated in bEnd.3 cells incubated with l-glutamate, CBZ or CBZ pretreated by l-glutamate for 30 min. Both the mRNA and protein levels of P-gp and CYP3A were remarkably reduced by PXR or NF-κB p65 knock-down by siRNA transfections. The decreased intracellular accumulation of Rho123 suggested that the expression of P-gp was enhanced in bEnd.3 cells. These data suggested that overexpression of P-gp and CYP3A during seizures and treated with CBZ may be regulated by PXR or NF-κB p65 activity and expression, which revealed a mechanism underlying the development of DRE.

The level of netrin-1 is decreased in newly diagnosed type 2 diabetes mellitus patients.

BACKGROUND: Pancreatic ß-cell dysfunction resulting from inflammation has been recognized to contribute to type 2 diabetes mellitus (T2DM). Netrin-1 is a new indicator of subclinical inflammation and it has a role in ß-cell apoptosis. This study evaluated the level of netrin-1 in newly diagnosed T2DM patients and explored whether netrin-1 is a reliable marker or a key factor in the development of T2DM. METHODS: Netrin-1 level was determined using a commercially available human enzyme-linked immune sorbent assay (ELISA) kit. The homeostasis model assessment of insulin resistance (HOMA-IR) was used as an index to measure insulin resistance. The sample consisted of 30 patients with newly diagnosed T2DM who had a glycosylated hemoglobin (HbA1c) level ranging from 7.5 % (58 mmol/mol) to 10.5 % (91 mmol/mol). The control group consisted of 26 healthy individuals matched for age and body mass index. RESULTS: The netrin-1 level of T2DM patients was significantly lower than that of healthy controls (p < 0.01). Logistic regression analysis showed that the level of netrin-1 was negatively correlated with HOMA-IR, fasting blood glucose, postprandial blood glucose, fasting insulin and HbA1c. CONCLUSIONS: Plasma netrin-1 levels were decreased in patients with newly diagnosed T2DM, and the levels of netrin-1 were negatively associated with IR and glucose homeostasis. Future studies on the precise mechanism will offer new insights into the prevention and treatment of T2DM.

Netrin-1 promotes mesenchymal stem cell revascularization of limb ischaemia.

This study examines the effect and mechanism of action of Netrin-1 on bone marrow mesenchymal stem cells in angiogenesis. Tube formation and migration of bone marrow mesenchymal stem cells were observed in cell culture. Bone marrow mesenchymal stem cells or Netrin-1-bone marrow mesenchymal stem cells were injected into the ischaemic area of the rat hind limb on the first day after surgery. Laser Doppler perfusion imaging was performed to analyse the levels of vascular endothelial growth factor in plasma and muscles, and immunohistochemistry and immunofluorescence were used to analyse angiogenesis. Bone marrow mesenchymal stem cells in medium containing Netrin-1 markedly increased the number of tubes formed and the migration of bone marrow mesenchymal stem cells compared with the untreated control group. The function of Netrin-1 in tube formation and migration is similar to vascular endothelial growth factor, and combined with vascular endothelial growth factor, Netrin-1 has more enhanced effect than in the other three groups. The Netrin-1-bone marrow mesenchymal stem cell group had better augmented blood-perfusion scores and vessel densities, as well as improved function of the ischaemic limb than that of the group injected with bone marrow mesenchymal stem cells (treated with bone marrow mesenchymal stem cells individually) or the control group (treated with medium). These results suggest that Netrin-1 has the ability to augment the angiogenesis of bone marrow mesenchymal stem cells and improve the function of the ischaemic hind limb by increasing the level of vascular endothelial growth factor.

Netrin-1 overexpression in bone marrow mesenchymal stem cells promotes functional recovery in a rat model of peripheral nerve injury.

Transplantation of bone marrow mesenchymal stem cells (BMSCs) has been developed as a new method of treating diseases of the peripheral nervous system. While netrin-1 is a critical molecule for axonal path finding and nerve growth, it may also affect vascular network formation. Here, we investigated the effect of transplanting BMSCs that produce netrin-1 in a rat model of sciatic nerve crush injury. We introduced a sciatic nerve crush injury, and then injected 1×10(6) BMSCs infected by a recombinant adenovirus expressing netrin-1 Ad5-Netrin-1-EGFP or culture medium into the injured part in the next day. At day 7, 14 and 28 after injection, we measured motor nerve conduction and detected mRNA expressions of netrin-1 receptors UNC5B and Deleted in Colorectal Cancer (DCC), and neurotrophic factors brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) by real-time PCR. We also detected protein expressions of BDNF and NGF by Western blotting assays and examined BMSCs that incorporated into myelin and vascellum. The results showed that BMSCs infected by Ad5-Netrin-1-EGFP significantly improved the function of the sciatic nerve, and led to increased expression of BDNF and NGF (P<0.05). Moreover, 28 days after injury, more Schwann cells were found in BMSCs infected by Ad5-Netrin-1-EGFP compared to control BMSCs. In conclusion, transplantation of BMSCs that produce netrin-1 improved the function of the sciatic nerve after injury. This method may be a new treatment of nerve injury.

Association of ALOX5AP rs10507391/SG13S114 A>T polymorphism with cerebral infarction in the Chinese population: a meta-analysis study.

Various studies have investigated that the single nucleotide polymorphisms (SNPs) rs10507391/SG13S114 A>T polymorphism could increase the risk of cerebral infarction, however these results still remain controversial. Therefore we conducted a meta-analysis to estimate the association of the 5-lipoxygenase-activating protein gene (ALOX5AP) rs10507391/SG13S114 A > T polymorphism with the incidence of cerebral infarction in the Chinese population. Our researchers searched PubMed, Embase, Web of Science databases, China Biological Medicine Database (CBMD), Wanfang Chinese database, and the Chinese National Knowledge Infrastructure (CNKI) database. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were extracted and pooled to assess the strength of the association between the ALOX5AP rs10507391/SG13S114 A>T polymorphism and incidence of cerebral infarction. A total of 12 eligible studies including 6,844 cases and 7,850 controls based on the search criteria were involved in this meta-analysis. The distributions of genotypes in the cases and controls were all in agreement with Hardy-Weinberg equilibrium. We observed that the ALOX5AP rs10507391/SG13S114 A>T polymorphism carried with T allele contrast model, the homozygote codominant model, the heterozygote codominant model, the dominant model and the recessive model (all the models p > 0.05) had no risk of cerebral infarction when all studies were pooled into the meta-analysis. The results of the meta-analysis indicate that ALOX5AP rs10507391/SG13S114 A>T polymorphism is not associated with the risk of cerebral infarction in the Chinese population.

DL-3-n-Butylphthalide protects rat bone marrow stem cells against hydrogen peroxide-induced cell death through antioxidation and activation of PI3K-Akt pathway.

Bone marrow stem cells (BMSCs) have been one of the most important cell sources for cell replacement therapy (CRT) in cerebral infarction. However, long-lasting oxidative stress during stroke, which plays an important role in neuron damage, deteriorates the microenvironment for cell survival, differentiation and removal. Thus the outcome of CRT in ischemic diseases was poor. DL-3-n-Butylphthalide (NBP) has protective effects on ischemic brain tissue through multiple mechanisms and has been used for stroke treatment in China for several years. In this study, hydrogen peroxide (H(2)O(2)) was used to induce oxidative stress injury to rat bone marrow stem cells (rBMSCs), imitating the microenvironment surrounding transplanted cells in the ischemic brain in vitro. The protective effects of NBP on rBMSCs against apoptosis induced by oxidative stress were investigated. Our results indicated that NBP could protect rBMSCs against apoptosis due to antioxidative properties and modulation of PI3K/Akt pathway. NBP could be used in combination with BMSCs for the treatment of cerebral infarction by improving the oxidative stress microenvironments and cell survival, however, further studies remain warranted.