Spermicidal efficacy of VRP, a synthetic cationic antimicrobial peptide, inducing apoptosis and membrane disruption

Abstract

Presently available contraceptives are mostly hormonal or detergent in nature with numerous side effects like irritation, lesion, inflammation in vagina, alteration of body homeostasis, etc. Antimicrobial peptides with spermicidal activity but without adverse effects may be suitable alternatives. In the present study, spermicidal activity of a cationic antimicrobial peptide VRP on human spermatozoa has been elucidated. Progressive forward motility of human spermatozoa was instantly stopped after 100 μM VRP treatment and at 350 μM, all kinds of sperm motility ceased within 20 s as assessed by the Sander-Cramer assay. The spermicidal effect was confirmed by eosin-nigrosin assay and HOS test. VRP treatment (100 μM) in human spermatozoa induced both the intrinsic and extrinsic pathways of apoptosis. TUNEL assay showed VRP treatment significantly disrupted the DNA integrity and changed the mitochondrial membrane permeability as evident from MPTP assay. AFM and SEM results depicted ultra structural changes including disruption of the acrosomal cap and plasma membrane of the head and midpiece region after treatment with 350 μM VRP. MTT assay showed after treatments with 100 and 350 μM of VRP for 24 hr, a substantial amount of Lactobacillus acidophilus (about 90% and 75%, respectively) remained viable. Hence, VRP being a small synthetic peptide with antimicrobial and spermicidal activity but tolerable to normal vaginal microflora, may be a suitable target for elucidating its contraceptive potentiality.

The cationic cell‐penetrating KT2 peptide promotes cell membrane defects and apoptosis with autophagy inhibition in human HCT 116 colon cancer cells

“…After peptide binding, peptides accumulate on the cell membrane, leading to membrane destabilization and permeabilization or the induction of cellular internalization of peptides (Baxter, Lay, Poon, Kvansakul, & Hulett, ). The information suggests recently that cationic peptides exhibit their functions in both cell membrane disruption and intracellular killing via the induction of apoptosis, autophagy, necrosis, and gene expression (Ghosh et al, ; Lee & Lee, ; Ren et al, ; P. Zhang et al, ). For example, the internalization of RL2, arginine‐rich peptide, induced caspase‐3‐dependent apoptotic cell death of cancer cells (Liu et al, ).…”

Antimicrobial peptides: features, applications and the potential use against covid-19

“…AMPs could be used as novel contraceptive microbicides. For example, VRP is a small synthetic peptide that can arrest sperm motility without damaging the vaginal epithelial cells [ 74 ].…”

A novel epididymal quiescence factor inhibits sperm motility by modulating NOS activity and intracellular NO‐cGMP pathway

“…Microscopic sperm motility was determined following the method described in Ghosh et al (2018). EP also contains anti-sticking property thus a specific amount of EP (0.6 mg protein/ml) was used in the assay to prevent the adhesion of sperm cells on the glass surface (Roy & Majumder, 1989).…”

“…The AFM observations of both spermatozoa and protein (QF) were performed with an Agilent Technologies (CA) 5500 ILM Pico plus AFM system with a piezo scanner maximum range of 100 μm (for spermatozoa) and 9 μm (for protein). Imaging of spermatozoa was carried out as described in Ghosh et al (2018). A total of 1 × 10 6 sperm cells were treated with PBS (control) and 2 μM of QF for 15 min and fixed with 4% paraformaldehyde.…”

“…2.2.14 | DNA fragmentation assayDetection of DNA fragmentation was done by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay using a standard APO-BrdU in situ DNA fragmentation assay kit (Biovision) as per manufacturer's protocol and as described inGhosh et al (2018).BrdU-FITC positive cells are DNA fragmented cells and the increase in fluorescence intensity indicates higher DNA fragmentation. In brief, 2 × 10 6 prepared sperm cells were treated with PBS (control), 1 and 2 μM QF for 15 min.…”