Title : Identifying key proteins associated with infertility induced by sperm immobilizing staphylococcus aureus in murine vaginal lavage fluid
Abstract:
In the context of a rapidly growing global population, the struggles and suffering of infertile couples deserve attention, underscoring the paradox of waning concerns about fertility. This research is based on the overlooked role of bacterial infections in female infertility. The study explores the proteomic analysis of pooled vaginal lavage fluid obtained from female BALB/c mice administered with 108 cfu of sperm immobilizing S. aureus in 20 µl PBS (test group, n=10) or 20 µl PBS alone (control group, n=10) via the intravaginal route for ten consecutive days; with a particular focus to detect the anti-fertility signature protein(s) associated with S. aureus induced infertility. Nano-LC-MS/MS analysis yielded five distinct bacterial proteins in the test group and no bacterial proteins in the control group, indicative of a vigorous proteomic response to bacterial exposure. Using gel filtration chromatography, the elution profile of test Vaginal Lavage Fluid (VLf) revealed a single prominent peak in the test group sample, that was further assessed for purity with SDS-PAGE indicating one unique protein band (~36 kDa). This protein aligned with GMP reductase, identified through protein profiling. Further, when the purified protein was tested for its impact on sperm parameters, the results showed that it impaired the sperm motility and viability in a concentration-dependent manner and disrupted sperm structural integrity when studied by using FE-SEM. Moreover, when the binding studies using FITC-labelled purified protein were conducted, it depicted presence of green fluorescence over entire surface of mouse spermatozoa. These results were akin to Sperm Immobilization Factor (SIF), already isolated and characterized in our laboratory, from culture supernatant of S. aureus, causing sperm impairment. Hence, taking into account all these factors, this protein (VLf) was designated as Vaginal Lavage fluid-derived Sperm Immobilization Factor (VLf-SIF). Through in-silico analysis, superimposition of VLf-SIF and SIF, already known to show sequence homology to cysteine-tRNA ligase, revealed close structural alignment, suggesting functional equivalence in sperm immobilization. Henceforth, this investigation provides compelling evidence for VLf-SIF, identified as GMP reductase, as a pivotal anti-fertility factor behind this bacterial-induced infertility.
Audience Take Away:
- This research highlights the significant influence of bacterial infections on female infertility, providing crucial insights into the antifertility factors involved.
- Attendees will learn about the significant impact of Staphylococcus aureus-derived proteins on female infertility, specifically focusing on the identification of VLf-SIF as an anti-fertility factor.
- By identifying key proteins associated with bacterial-induced infertility, this research aims to establish a basis for developing reliable diagnostic biomarkers, paving the way for innovative approaches to address this pressing global health issue.
