Anti-VDAC3 recombinant antibody decreased human sperm motility and membrane integrity: A potential spermicide for contraception

Objective:To express recombinant protein that comprises an important fragment of human sperm specific voltage dependent anion channel 3 (VDAC3) protein as a potential molecule for generation of antibody, which can affect sperm function, aiming at spermicide development. Methods: The produce of VDAC3 recombinant protein encoded by cDNA sequence of human VDAC3 exon 5-8, based on experimental design of VDAC3 knock-out mice study. And after the purification of various human sperm VDAC3 recombinant proteins, epitope has been predicted in our recombinant protein determined by ElliPro program. Polyclonal antibody was produced for 14 wk. Then anti-VDAC3-exon 5-8 recombinant antiserum was inoculated to human sperm. After the process, antibody VDAC3 protein in human sperm was incubation with anti-VDAC3 recombinant antibody. Finally evaluation the effect of VDAC3 antiserum to human sperm motility and plasma membrane integrity was proceeded.Results: Human VDAC3 recombinant protein was successfully over-expressed in Escherichia coli and purified by affinity chromatography method. Purified human sperm VDAC3 recombinant protein could stimulate immune response in rabbit producing an antibody against VDAC3. Anti-VDAC3 recombinant antibody recognized VDAC3 antigen in human sperm could decrease human sperm motility and membrane integrity significantly.Conclusions:Anti-VDAC3 recombinant polyclonal antibody that we produced in rabbit by ourselves could decrease sperm motility and sperm membrane integrity. The authors suggest this polyclonal antibody could be used as a candidate agent for male contraception in the future. Furthermore, the authors intend to explore the effect of this antibody into sperm function aiming at male contraceptive vaccine development.

Effect of varicocele repair on sperm retrieval rate and testicular histopathological patterns in men with nonobstructive azoospermia

Varicocele adversely affects semen parameters.However,the effect of varicocele repair on the sperm retrieval rate and testicular histopathological patterns in men with nonobstructive azoospermia has not been widely reported.We retrospectively assessed the sperm retrieval rates and testicular histopathological patterns in men with nonobstructive azoospermia who were referred to the Urology Clinic in Dr.Cipto Mangunkusumo Hospital(Jakarta,Indonesia)and Bunda General Hospital(Jakarta,Indonesia)between January 2009 and December 2019.We compared patients who had undergone a surgical sperm retrieval procedure for assisted reproductive technology no earlier than three months after varicocele repair and those who had not undergone varicocele repair.The study included 104 patients(age range:26–54 years),42 of whom had undergone varicocele repair before the sperm retrieval procedure and 62 who had not.Motile spermatozoa were found in 29(69.1%)and 17(27.4%)patients who had undergone varicocele repair before the sperm retrieval procedure and those who had not undergone the repair,respectively(relative risk:2.51;95%confidence interval:1.60–3.96;P<0.001).A predicted probabilities graph showed consistently higher sperm retrieval rates for patients with varicocele repair,regardless of their follicle-stimulating hormone levels.Patients who underwent varicocele repair showed higher testicular histopathological patterns(P=0.001).In conclusion,men with nonobstructive azoospermia and clinical varicocele who underwent varicocele repair before the sperm retrieval procedure had higher sperm retrieval rates compared to those who did not undergo varicocele repair.

In silico docking analysis of beta-defensin 20 against cation channel sperm-associated protein 1–4 to predict its role in the sperm maturation

Beta-defensin 20(DEFB20)is widely expressed in the epididymis with gene features involved in epididymal sperm maturation.However,the action mechanism and function of DEFB20 in sperm maturation are still unclear.One of the important roles of beta-defensin is the ion channel activity.The cation channel sperm-associated protein(CatSper)alpha is an ion channel protein found on the sperm surface.This study aimed to investigate the interaction between DEFB20 and CatSper1–4 protein in relation to the sperm maturation process.Protein sequences were obtained from the National Center for Biotechnology Information(NCBI).Protein modeling and validation were carried out by using the Robetta modeling server and the Ramachandran plot method.Rosetta web server was used for the docking analysis.The results revealed a natural interaction between DEFB20 and CatSper1–4.The interaction occurred at the cation channel(close to the casein kinase II),ion transport protein,and kinase c phosphorylation of the CatSper1–4 active site.The DEFB20 region interacting with CatSper2–4 was the beta-defensin domain,while with CatSper1 was the non-beta-defensin domain.Based on the analysis,DEFB20 may interact with CatSperαsubunits,particularly CatsSper1,to affect ion channel activity during sperm maturation.