[Impact of the CFTR chloride channel on the cytoskeleton of mouse Sertoli cells].

OBJECTIVE: To study the impact of the chloride channel dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) on the cytoskeleton of Sertoli cells in the mouse. METHODS: TM4 Sertoli cells were cultured and treated with CFTR(inh)-172 at the concentrations of 1, 5, 10 and 20 µmol/L for 48 hours. Then the cytotoxicity of CFT(inh)-172 was assessed by CCK-8 assay, the expressions of F-actin and Ac-tub in the TM4 Sertoli cells detected by immunofluorescence assay, and those of N-cadherin, vimentin and vinculin determined by qPCR. RESULTS: CFTR(inh)-172 produced cytotoxicity to the TM4 Sertoli cells at the concentration of 20 µmol/L. The expressions of F-actin and Ac-tub were decreased gradually in the TM4 Sertoli cells with the prolonging of treatment time and increasing concentration of CFTR(inh)-172 (P < 0.05). The results of qPCR showed that different concentrations of CFTR(inh)-172 worked no significant influence on the mRNA expressions of N-cadherin, vimentin and vinculin in the Sertoli cells. CONCLUSION: The CFTR chloride channel plays an important role in maintaining the normal cytoskeleton of Sertoli cells. The reduced function and expression of the CFTR chloride channel may affect the function of Sertoli cells and consequently spermatogenesis of the testis.

Nifedipine promotes the proliferation and migration of breast cancer cells.

Nifedipine is widely used as a calcium channel blocker (CCB) to treat angina and hypertension,but it is controversial with respect the risk of stimulation of cancers. In this study, we demonstrated that nifedipine promoted the proliferation and migration of breast cancer cells both invivo and invitro. However, verapamil, another calcium channel blocker, didn't exert the similar effects. Nifedipine and high concentration KCl failed to alter the [Ca2+]i in MDA-MB-231 cells, suggesting that such nifedipine effect was not related with calcium channel. Moreover, nifedipine decreased miRNA-524-5p, resulting in the up-regulation of brain protein I3 (BRI3). Erk pathway was consequently activated and led to the proliferation and migration of breast cancer cells. Silencing BRI3 reversed the promoting effect of nifedipine on the breast cancer. In a summary, nifedipine stimulated the proliferation and migration of breast cancer cells via the axis of miRNA-524-5p-BRI3-Erk pathway independently of its calcium channel-blocking activity. Our findings highlight that nifedipine but not verapamil is conducive for breast cancer growth and metastasis, urging that the caution should be taken in clinic to prescribe nifedipine to women who suffering both hypertension and breast cancer, and hypertension with a tendency in breast cancers.

[Expression of heme oxygenase enzyme in the testis tissue and azoospermia].

OBJECTIVE: To investigate the location of heme oxygenase (HO) enzyme in the human testis, and explore the correlation of the expression of HO enzyme with azoospermia by analyzing its different expression levels in the testes of nonobstructive azoospermia, obstructive azoospermia and normal men. METHODS: We detected the location of the cells expressing HO enzyme in the human testis tissue using immunohistochemistry, determined the mRNA and protein expression levels of HO-1 and HO-2 in the testes of azoospermia patients and normal healthy men by RT-fluorescence quantitative PCR (RT-FQ-PCR) and Western blot, and explored the correlation of HO expressions with the pathogenesis of azoospermia. RESULTS: HO-1 enzyme was expressed mainly in the Sertoli cells and HO-2 enzyme chiefly in the germ cells of the testis tissue. RT-FQ-PCR showed that the expression of HO-1 in the testis tissue was significantly lower in the nonobstructive azoospermia than in the normal and obstructive azoospermia groups (P < 0.05), with no significant difference between the latter two. Western blot revealed no obvious difference between the expression level of HO-1 protein and that of HO-1 mRNA. There were no differences in the expression level of HO-2 protein among the three groups. CONCLUSION: The expression level of HO enzyme is significantly decreased in the testis tissue of nonobstructive azoospermia patients, and the expression of HO-1 protein is consistent with that of HO-1 mRNA. As HO-1 protects the testis tissue against various stress injuries through its antioxidant, anti-inflammatory and anti-apoptotic effects, its decreased expression level may be correlated with spermatogenic dysfunction, and therefore considered as a possible mechanism of nonobstructive azoospermia.

Role of the epithelial sodium channel in salt-sensitive hypertension.

The epithelial sodium channel (ENaC) is a heteromeric channel composed of three similar but distinct subunits, α, ß and γ. This channel is an end-effector in the rennin-angiotensin-aldosterone system and resides in the apical plasma membrane of the renal cortical collecting ducts, where reabsorption of Na(+) through ENaC is the final renal adjustment step for Na(+) balance. Because of its regulation and function, the ENaC plays a critical role in modulating the homeostasis of Na(+) and thus chronic blood pressure. The development of most forms of hypertension requires an increase in Na(+) and water retention. The role of ENaC in developing high blood pressure is exemplified in the gain-of-function mutations in ENaC that cause Liddle's syndrome, a severe but rare form of inheritable hypertension. The evidence obtained from studies using animal models and in human patients indicates that improper Na(+) retention by the kidney elevates blood pressure and induces salt-sensitive hypertension.

Gonadotropin-releasing hormone positively regulates steroidogenesis via extracellular signal-regulated kinase in rat Leydig cells.

Gonadotropin-releasing hormone (GnRH) is secreted from neurons within the hypothalamus and is necessary for reproductive function in all vertebrates. GnRH is also found in organs outside of the brain and plays an important role in Leydig cell steroidogenesis in the testis. However, the signalling pathways mediating this function remain largely unknown. In this study, we investigated whether components of the mitogen-activated protein kinase (MAPK) pathways are involved in GnRH agonist (GnRHa)-induced testis steroidogenesis in rat Leydig cells. Primary cultures of rat Leydig cells were established. The expression of 3ß-hydroxysteroid dehydrogenase (3ß-HSD) and the production of testosterone in response to GnRHa were examined at different doses and for different durations by RT-PCR, Western blot analysis and radioimmunoassay (RIA). The effects of GnRHa on ERK1/2, JNK and p38 kinase activation were also investigated in the presence or absence of the MAPK inhibitor PD-98059 by Western blot analysis. GnRHa induced testosterone production and upregulated 3ß-HSD expression at both the mRNA and protein levels; it also activated ERK1/2, but not JNK and p38 kinase. Although the maximum effects of GnRHa were observed at a concentration of 100 nmnol L⁻¹ after 24 h, activation of ERK1/2 by GnRHa reached peak at 5 min and it returned to the basal level within 60 min. PD-98059 completely blocked the activation of ERK1/2, the upregulation of 3ß-HSD and testosterone production. Our data show that GnRH positively regulates steroidogenesis via ERK signalling in rat Leydig cells. ERK1/2 activation by GnRH may be responsible for the induction of 3ß-HSD gene expression and enzyme production, which may ultimately modulate steroidogenesis in rat Leydig cells.

Apolipoprotein E polymorphism influences lipid phenotypes in Chinese families with familial combined hyperlipidemia.

BACKGROUND: Apolipoprotein E (apoE) polymorphism is associated with changes in the lipoprotein profile of individuals with familial combined hyperlipidemia (FCHL), but its effects on the lipoprotein profiles of members of Chinese families with FCHL remain uncertain. METHODS AND RESULTS: 43 FCHL families (n=449) and 9 normolipidemic families (n=73) were recruited to assess the influence of apoE polymorphism on plasma lipids. The relative frequency of the epsilon4 allele in affected and unaffected FCHL relatives, spouses and normolipidemic members was 13.8%, 5.3%, 9.1% and 6.8%, respectively, with a significantly higher frequency in affected FCHL relatives, compared with unaffected FCHL relatives or normolipidemic members (p=0.0002 or p=0.029). In FCHL relatives, the apoE4 subset (E4/4 and E4/3) exhibited significantly higher levels of apoB, total cholesterol and low-density lipoprotein-cholesterol (LDL-C) than did the apoE3 (E3/3) subset, especially in women (all p<0.05), and there was significant elevation of LDL-C concentrations in men only (p<0.05). In men, the apoE2 (E3/2) subset indicated a decreased level of apoB and increased apoA1 compared with those in the apoE3 subset (p<0.05). CONCLUSIONS: ApoE polymorphism appears to be associated with variance of the lipoprotein phenotype in Chinese families with FCHL.