Human male gamete endocrinology: 1alpha, 25-dihydroxyvitamin D3 (1,25(OH)2D3) regulates different aspects of human sperm biology and metabolism

<p>Abstract</p> <p>Background</p> <p>A wider biological role of 1alpha,25-Dihydroxyvitamin D3 (1,25(OH)2D3), the active metabolite of vitamin D3, in tissues not primarily related to mineral metabolism was suggested. Recently, we evidenced the ultrastructural localization the 1,25(OH)2D3 receptor in the human sperm. However, the 1,25(OH)2D3 action in human male reproduction has not yet been clarified.</p> <p>Methods and Results</p> <p>By RT-PCR, Western blot and Immunofluorescence techniques, we demonstrated that human sperm expresses the 1,25(OH)2D3 receptor (VDR). Besides, 25(OH)D3-1 alpha-hydroxylase, evidenced by Western blot analysis, indicated that in sperm 1,25(OH)2D3 is locally produced, highlighting the potential for autocrine-paracrine responses. 1,25(OH)2D3 through VDR, increased intracellular Ca2+ levels, motility and acrosin activity revealing an unexpected significance of this hormone in the acquisition of fertilizing ability. In sperm, 1,25(OH)2D3 through VDR, reduces triglycerides content concomitantly to the increase of lipase activity. Rapid responses stimulated by 1,25(OH)2D3 have been observed on Akt, MAPK and GSK3 implying that this secosteroid is involved in different sperm signalling pathways.</p> <p>Conclusion</p> <p>Our data extended the role of 1,25(OH)2D3 beyond its conventional physiological actions, paving the way for novel therapeutic opportunities in the treatment of the male reproduction disorders.</p

Importance of Non-Selective Cation Channel TRPV4 Interaction with Cytoskeleton and Their Reciprocal Regulations in Cultured Cells

BACKGROUND: TRPV4 and the cellular cytoskeleton have each been reported to influence cellular mechanosensitive processes as well as the development of mechanical hyperalgesia. If and how TRPV4 interacts with the microtubule and actin cytoskeleton at a molecular and functional level is not known. METHODOLOGY AND PRINCIPAL FINDINGS: We investigated the interaction of TRPV4 with cytoskeletal components biochemically, cell biologically by observing morphological changes of DRG-neurons and DRG-neuron-derived F-11 cells, as well as functionally with calcium imaging. We find that TRPV4 physically interacts with tubulin, actin and neurofilament proteins as well as the nociceptive molecules PKCepsilon and CamKII. The C-terminus of TRPV4 is sufficient for the direct interaction with tubulin and actin, both with their soluble and their polymeric forms. Actin and tubulin compete for binding. The interaction with TRPV4 stabilizes microtubules even under depolymerizing conditions in vitro. Accordingly, in cellular systems TRPV4 colocalizes with actin and microtubules enriched structures at submembranous regions. Both expression and activation of TRPV4 induces striking morphological changes affecting lamellipodial, filopodial, growth cone, and neurite structures in non-neuronal cells, in DRG-neuron derived F11 cells, and also in IB4-positive DRG neurons. The functional interaction of TRPV4 and the cytoskeleton is mutual as Taxol, a microtubule stabilizer, reduces the Ca2+-influx via TRPV4. CONCLUSIONS AND SIGNIFICANCE: TRPV4 acts as a regulator for both, the microtubule and the actin. In turn, we describe that microtubule dynamics are an important regulator of TRPV4 activity. TRPV4 forms a supra-molecular complex containing cytoskeletal proteins and regulatory kinases. Thereby it can integrate signaling of various intracellular second messengers and signaling cascades, as well as cytoskeletal dynamics. This study points out the existence of cross-talks between non-selective cation channels and cytoskeleton at multiple levels. These cross talks may help us to understand the molecular basis of the Taxol-induced neuropathic pain development commonly observed in cancer patients

Notch signaling pathway in cumulus cells can be a novel marker to identify poor and normal responder IVF patients

PURPOSE: To identify expression of Notch signaling proteins and its ligands in human cumulus cells which were obtained by follicle aspiration and to compare the differences of this protein expression between the normal and poor responder patients. METHODS: 47 patients who applied to the assisted reproductive treatments with various infertility problems were included to the study. Controlled ovarian hyperstimulation was performed by using GnRH agonist and gonadotropins. Serum hormon levels were measured by using Chemilluminescent Microparticle Immunoassay method for each patient. After ultrasonographic ovarian follicle screening, oocytes were retrievaled. Cumulus cells obtained from the follicles were cultured for 72 h and immunuhistochemistry were performed for Notch1, Notch2, Notch3, Notch4, Jagged1 and Jagged2 proteins. Histological score (HSCORE) were applied to all of the samples. The association between Notch and its ligands protein expressions and the oocyte-embryo quality and fertilization rates were investigated. RESULTS: Significant differences were observed between the mean values of age, AMH and FSH in the 2 groups, respectively (p < 0.05). However, the mean female infertility duration and total gonadotropin dose did not differ significantly between normal and poor responder groups. All the patients cumulus cells expressed Notch1, Notch2, Notch3, Notch4, Jagged1 and Jagged2. There was a significant difference (p < 0.05) only for Notch2 between the 2 groups and a positive correlation between Notch2 and Notch3 (r = 547, p = 0.00) expressions were noted. Furthermore, no correlations were observed between the following: Notch1, Notch2, Notch3, Notch4, Jagged1, and Jagged2 expression; mature oocyte number; fertilization rates, and embryo quality percentage in both of the groups. CONCLUSION: Notch signalling proteins can be an indicator for understanding the ovarian response in ovulation induction