Contraceptive efficacy of sperm agglutinating factor from Staphylococcus warneri, isolated from the cervix of a woman with inexplicable infertility

Abstract

BackgroundVoluntary control of fertility is of paramount importance to the modern society. But since the contraceptive methods available for women have their limitations such as urinary tract infections, allergies, cervical erosion and discomfort, a desperate need exists to develop safe methods. Vaginal contraceptives may be the answer to this problem, as these are the oldest ways of fertility regulation, practiced over the centuries. With minimal systemic involvement, these are also the safest. Natural substances blocking or impairing the sperm motility offer as valuable non-cytotoxic vaginal contraceptives. Antimicrobial peptides (AMPs) isolated from plants, animals and microorganisms are known to possess sperm immobilizing and spermicidal properties. Following this, in the quest for alternative means, we have cloned, over expressed and purified the recombinant sperm agglutinating factor (SAF) from Staphylococcus warneri, isolated from the cervix of a woman with unexplained infertility.MethodsGenomic library of Staphylococcus warneri was generated in Escherichia coli using pSMART vector and screened for sperm agglutinating factor (SAF). The insert in sperm agglutinating transformant was sequenced and was found to express ribonucleotide-diphosphate reductase-α sub unit. The ORF was sub-cloned in pET28a vector, expressed and purified. The effect of rSAF on motility, viability, morphology, Mg++-dependent ATPase activity and acrosome status of human sperms was analyzed in vitro and contraceptive efficacy was evaluated in vivo in female BALB/c mice.ResultsThe 80 kDa rSAF showed complete sperm agglutination, inhibited its Mg2+-ATPase activity, caused premature sperm acrosomal loss in vitro and mimicked the pattern in vivo showing 100% contraception in BALB/c mice resulting in prevention of pregnancy. The FITC labeled SAF was found to bind the entire surface of spermatozoa. Vaginal application and oral administration of rSAF to mice for 14 successive days did not demonstrate any significant change in vaginal cell morphology, organ weight and tissue histology of reproductive and non-reproductive organs and had no negative impact in the dermal and penile irritation tests.ConclusionThe Sperm Agglutinating Factor from Staphylococcus warneri, natural microflora of human cervix, showed extensive potential to be employed as a safe vaginal contraceptive.

Staphylococcus-Induced Bacteriospermia In Vitro: Consequences on the Bovine Spermatozoa Quality, Extracellular Calcium and Magnesium Content

“…Subsequently, it was found that this factor also inhibits mitochondrial Mg 2+ -ATPase activity [ 26 ]. Similarly, a sperm agglutinating factor (SAF) was previously isolated from S. warneri and its recombinant version was recently proved as spermicidal in vitro, but also as an excellent contraception in vivo [ 27 ]. As mitochondrial membrane potential may predict 4-h sperm motility [ 28 ], intact mitochondria are an essential factor of sperm motion.…”

Role of Lactobacillus in Female Infertility Via Modulating Sperm Agglutination and Immobilization

“…Pant et al. isolated an 80 kDa sperm agglutination factor from Staphylococcus warneri ; it also inhibits Mg 2+ -dependent ATPase activity and showed a potent contraceptive effect in mouse models ( Pant et al., 2019 ). Ohri et al.…”

“…These data indicate that the Mg 2+ -dependent ATPase plays an important role on sperm motility function. Pant et al isolated an 80 kDa sperm agglutination factor from Staphylococcus warneri; it also inhibits Mg 2+ -dependent ATPase activity and showed a potent contraceptive effect in mouse models (Pant et al, 2019). Ohri et al isolated a 70 kDa protein from the cell culture of S. aureus; this protein mediates a tail-to-tail agglutination of spermatozoa (Ohri and Prabha, 2005).…”

Ejaculatory Abstinence Affects the Sperm Quality in Normozoospermic Men—How Does the Seminal Bacteriome Respond?

“…In the meantime, P fimbriae often found in E. coli strains during acute prostatitis [ 62 ] recognizes a-D-galp-l-4-9-D-galp (gal gal) located primarily in the sperm tail [ 65 ]. In the case of G + bacteria, particularly staphylococci, a group of proteins called microbial surface components recognize adhesive matrix molecules target proteins in the host’s extracellular matrix [ 59 ] and induce a strong affinity to selected hydrophobic molecules once the adhesion process is initiated [ 66 ]. A particular colonization advantage in staphylococci is provided by the so-called moonlight proteins that act as particularly resilient adhesins [ 59 , 67 ].…”