Wnt/β-catenin signal pathway mediated Salidroside induced directional differentiation from mouse mesenchymal stem cells to nerve cells / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To explore the molecule mechanism of Salidroside inducing directional differentiation of mouse mesenchymal stem cells (MSCs) into neuronal cells.</p><p><b>METHODS</b>The mouse multipotent mesenchymal precursor cell line (D1) was taken as the objective. Cultured MSCs were divided into the negative control group (complete culture solution), the positive control group (containing 1 mmol/L β-mercaptoethanol), the Salidroside induced group (20 mg/L Salidroside), and the blocked group (20 ng/ ml DKK1, a special inhibitor of Wnt/β-catenin signal pathway). All cells were inoculated in a 6-well plate (1 x 10(4) cells/cm2) and grouped for 24 h. The expression of p-catenin was detected by fluorescence Immunochemistry in the negative control group, the positive control group, and the Salidroside induced group. The expression of neuron-specific enolase (NSE), beta 3 class III tubulin (β-tubulin III), nuclear receptor related factor 1 (Nurr1), glial fibrillary acidic protein (GFAP) mRNA, Wnt3a, β-catenin, low-density lipoprotein receptor-related protein6 (LRP6), Axin mRNA were detected using reverse transcrip- tion PCR (RT-PCR). The expression of β-catenin and NSE protein were analyzed by Western blot in the negative control group, the positive control group, and the Salidroside induced group. Ca2+ chelating agents (EGTA), L-type Ca2+ channel blocker (Nifedpine), and IP3Ks special inhibitor (LY294002) were used to block Ca2+ signal pathway respectively. The expression of Wnt3a, LRP-6, Axin, glycogen syn- thase kinase (GSK-3), and β-catenin mRNA were detected by RT-PCR. The β-catenin protein expression was analyzed using Western blot.</p><p><b>RESULTS</b>Compared with the positive control group, β-catenin protein was strong positively expressed; the expression of Wnt3a, β-catenin, LRP6, Axin, NSE, β-tubulin III, Nurr1 mRNA, and NSE protein were obviously up-regulated in the Salidroside induced group (P < 0.01). Compared with the positive control group and the Salidroside induced group, β-catenin, NSE, Nurr1, and β-tubulin III mRNA expression decreased; β-catenin and NSE protein expression were also down-regulated in the blocked group (P < 0.01). Compared with the Salidroside induced group, the expression of Wnt3a, LRP-6, β-catenin, and Axin mRNA were down-regulated in the Ca2+ signal blocked group and the salidroside induced group (P < 0.01, P < 0.05).</p><p><b>CONCLUSION</b>Salidroside affected directional differentia- tion of MSCs into neuronal cells through Wnt/β-catenin and Ca2+ signal pathway.</p>

Androgen Receptor-dependent Expression of Low-density Lipoprotein Receptor-related Protein 6 is Necessary for Prostate Cancer Cell Proliferation

Androgen receptor (AR) signaling is important for prostate cancer (PCa) cell proliferation. Here, we showed that proliferation of hormone-sensitive prostate cancer cells such as LNCaP was significantly enhanced by testosterone stimulation whereas hormone-insensitive prostate cancer cells such as PC3 and VCaP did not respond to testosterone stimulation. Blocking of AR using bicalutamide abolished testosterone-induced proliferation of LNCaP cells. In addition, knockdown of AR blocked testosterone-induced proliferation of LNCaP cells. Basal expression of low-density lipoprotein receptor-related protein 6 (LRP6) was elevated in VCaP cells whereas stimulation of testosterone did not affect the expression of LRP6. However, expression of LRP6 in LNCaP cells was increased by testosterone stimulation. In addition, knockdown of LRP6 abrogated testosterone-induced proliferation of LNCaP cells. Given these results, we suggest that androgen-dependent expression of LRP6 plays a crucial role in hormone-sensitive prostate cancer cell proliferation.

Regulation of microRNA-7-5p and LRP6 by Epstein-Barr Virus-Encoded RNAs in Burkitt's Lymphoma Cell Line Akata

Epstein-Barr virus (EBV)-encoded small non-coding RNAs (EBERs) are abundantly expressed in various EBV-associated malignancies, and play critical roles in cell proliferation, tumorigenesis, and apoptosis resistance. However, the mechanism how EBERs regulate cell function awaits further clarification. In this study, we investigated the effect of EBERs on the expression of cellular microRNA (miRNA) and mRNA expression. To test the effect of EBERs while unaffected by other EBV genes, we used EBERs-deleted recombinant EBV infected Burkitt's lymphoma cell line (Akata(+)EBERs(-)) as well as EBV-infected (Akata(+)) and EBV uninfected (Akata(-)) cell lines. They all have the same genetic backgrounds. First, 15 different cellular miRNAs which have reverse complementary sequences to EBERs and have reported targets were selected by bioinformatics analysis. When RT-PCR was carried out for the 16 miRNAs using RNAs from Akata(+), Akata(-), and Akata(+)EBERs(-) cells, hsa-miR-7-5p was the only one showing down-regulated expression in Akata(+) than in Akata(-) and Akata(+)EBERs(-) cells. Bioinformatics and mRNA microarray analyses for Akata(+), Akata(-), and Akata(+)EBERs(-) cell lines were then carried out to predict putative targets of hsa-miR-7-5p. Among the 6 predicted targets of hsa-miR-7-5p, only low density lipoprotein receptor-related protein 6 (LRP6) was up-regulated in EBERs-expressing cells when tested by RT-PCR and Western blot. However, luciferase reporter assay showed that the 3'-UTR of LRP6 was not directly targeted by hsa-miR-7-5p. Our data suggest that both hsa-miR-7-5p and LRP6 are regulated by EBERs in Akata cells, and these genes may partly mediate the tumorigenic function of EBERs in Burkitt's lymphoma.

Association of common polymorphisms in the LRP6 gene with sporadic coronary artery disease in a Chinese population / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Genetic factors contribute to the development of coronary artery disease (CAD). Recently, a missense mutation in the low density lipoprotein receptor related protein 6 (LRP6) gene, encoding low density lipoprotein receptor related protein 6, has been implicated in an autosomal dominant form of early-onset CAD. The aim of this study was to determine whether the common variants in LRP6 are associated with sporadic CAD in Chinese.</p><p><b>METHODS</b>A total of 766 CAD patients and 806 healthy controls were included in this study. The presence of angiographic CAD was determined by coronary angiographic analysis. Six signal nucleotide polymorphisms (SNPs) were genotyped using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique.</p><p><b>RESULTS</b>A significant association was detected between rs11054731 in LRP6 intron 2 and CAD in our cohort (P = 0.001). The CC genotype and C allele frequency in the case group were 52% and 72%. Using a dominant model of inheritance, the C allele of rs11054731 was shown to be an independent risk factor for CAD with an OR of 1.45 (95%CI: 1.19 - 1.77, P = 0.0002). With the stratification according to the number of affected coronary arteries, an association was observed between rs11054731 and CAD (P = 0.0002). No significant association was observed between any other SNPs and the risk of CAD.</p><p><b>CONCLUSION</b>The C allele of the rs11054731 within the LRP6 gene was associated with increased risk and extent of CAD in Chinese.</p>