DPT Is A Novel Regulatory Protein In Cdcl₂Induced Claudin-11Decrease

Objective:Cadmium (Cd), a kind of ubiquitous environmental heavy metal, maybe harmful to the reproductive system by destroying blood-testis barrier(BTB). The underlying mechanisms of its adverse effects on BTB, however,are still unclear. In our preliminary study, we found a significant increasein dermatopontin (DPT) expression in Cdcl2-treated Sertoli cells in vitro,suggesting that the increasing DPT expression might be crucial for BTBdamage which induced by cadmium chloride（Cdcl2）.Therefore, the presentstudy explores the possible involvement of DPT in the Cdcl2-inducedsuppression of claudin-11expression.Methods:1. Using immunohistochemistry and immunofluorescence methods tolocalize DPT protein in the testis.2. Real-Time RT-PCR and westernblotting were employed toidentify the expression levels of DPT，and to explore the effects of Cdcl2on the expression of DPT and claudin-11in mouse testis and15p-1Sertoli cells.3. Using RNAi lentivirus-mediated DPT silenced15p-1Sertoli cellmodel to futher study its relationship with Cdcl2-mediateddownregulation of claudin-11.Results:1. DPT signal was detected in both the Sertoli cells and the interstitialarea, while DPT was not detected in germ cells.Immunocytofluorescent staining of DPT in15p-1cells indicates thatDPT is located within the cytoplasm.2. With the3.5mg/kg Cdcl2treated in mice testes and20μmol Cdcl2treated in15p-1Sertoli cells separately, we observed an increasingtime-dependent of DPT mRNA and protein expression. Whereas theexpression of claudin-11is in contrast, showing time-dependentdecrease.3. DPT silenced mediated by lentivirus could partly restore thedeclining expression of claudin-11induced by Cdcl2.4. Cdcl2induced the alteration of DPT expression, at least partly, viathe P38signaling pathway.Conclusions: In summary, our studies provide the evidences that DPT is located intestis Sertoli cells. P38was activated under the stimulation of Cdcl2, whichlead to a significant increase in DPT and followed by a decrease inclaudin-11, potentially resulting in BTB impairment. Therefore, DPT is anovel regulatory protein which mediated Cdcl2to induce claudin-11decrease.