Anti-KLK7 (aa 36-130) polyclonal antibody

ObjectivesKallikrein 7 (KLK7) is a secreted serine protease that plays important roles in skin desquamation and tumour progression, which makes it an attracting drug target. To guide the design of KLK7 inhibitors, a series of coumarin-based inhibitors were used to perform 3D-quantitative structure-activity relationship analysis. Methods3D conformations of 37 inhibitors were generated and used to construct CoMFA and CoMSIA models. Then a complex model between the inhibitors and KLK7 was built with molecular docking. Key findingsWith the training set, the CoMFA and CoMSIA models achieved q(2) values of 0.521 and 0.498, and r(2) values of 0.942 and 0.983, respectively. With the testing set, the predicted r(2) values were 0.663 and 0.669, respectively, for CoMFA and CoMSIA. 3D contour maps from these two models identified steric and hydrophobic interactions as the most important molecular features of these inhibitors. Furthermore, molecular docking study was performed to understand the binding modes between these compounds and KLK7, in which the critical steric and hydrophobic interactions between the inhibitors and KLK7 were confirmed. ConclusionsSteric and hydrophobic interactions are critical in the efficient binding of KLK7 inhibitors. Our analysis would provide a meaningful guideline for the rational design of novel KLK7 inhibitors.

STUDY QUESTION: Are kallikreins (KLKs), the whey-acidic-protein four-disulfide core domain (WFDCs) and their neighbors, semenogelins (SEMGs), known to play a role in the cascade of semen coagulation and liquefaction, associated with male infertility? SUMMARY ANSWER: Several KLK and SEMG variants are overrepresented among hyperviscosity, asthenozoospermia and oligozoospermia, supporting an effect of abnormal semen liquefaction on the loss of semen quality and in lowering male reproductive fitness. WHAT IS KNOWN ALREADY: In the cascade of semen coagulation and liquefaction the spermatozoa coated by EPPIN (a protease inhibitor of the WFDC family) are entrapped in a cross-linked matrix established by SEMGs. After ejaculation, the SEMG matrix is hydrolyzed by KLK3/2 in a fine-tuned process regulated by other KLKs that allows the spermatozoa to increase motility. STUDY DESIGN SIZE, DURATION: This study includes a cohort of 238 infertility-related cases and 91 controls with normal spermio-gram analysis. The remaining 126 controls are healthy males with unknown semen parameters. Sample collection was carried out from June 2011 to January 2015 and variant screening from May 2013 to August 2015. PARTICIPANTS/MATERIALS, SETTING, METHODS: We performed a screening by massive parallel sequencing in a pooled sample (N = 222) covering approximately 93 kb of KLK (19q13.3-13.4) and WFDC (20q13) clusters, followed by the genotyping of most promising variants in the full cohort. MAIN RESULTS AND THE ROLE OF CHANCE: Overall, 160 common and 296 low-frequency variants passed the quality control filtering. Statistical tests disclosed an association with hyperviscosity of a KLK7 regulatory variant (P = 0.0035), and unveiled a higher burden of deleterious mutations in KLKs than expected by chance (P = 0.0106). KLK variants found to be overrepresented in cases included two substitutions likely affecting the substrate binding pocket, two nonsynonymous variants overlapping in the three-dimensional structure and two mutations mapping in consecutive N-terminal residues. Other variants identified in SEMGs possibly contributing to hyperviscosity and asthenozoospermia consisted of three replacements predicted to modify targets of proteolysis (P = 0.0442 for SEMGI p.Gly400Asp) and a copy number variation associated with a reduced risk of oligozoospermia (P = 0.0293). LARGE SCALE DATA: Not applicable. LIMITATIONS REASONS FOR CAUTION: The sampling of a few hundred individuals has limited power to detected associations with low-frequency variants and only a small set of variants was prioritized for genotyping. Other susceptibility variants for male infertility may remain unidentified. WIDER IMPLICATIONS OF THE FINDINGS: We provide important evidence for an effect of KLKs and SEMGs variability on semen quality and for modifications in the process of semen liquefaction as a possible cause for male infertility.