Background Oocyte activation is driven by intracellular calcium (Ca2+) oscillations induced by sperm‐specific PLCζ, abrogation of which causes oocyte activation deficiency in humans. Clinical PLCζ investigations have been limited to severe male infertility conditions, while PLCζ levels and localisation patterns have yet to be associated with general sperm viability. Materials and Methods PLCζ profiles were examined within a general population of males attending a fertility clinic (65 patients; aged 29‐53), examining PLCζ throughout various fractions of sperm viability. Male recruitment criteria required a minimum sperm count of 5 × 106 spermatozoa/mL, while all female patients included in this study yielded at least five oocytes for treatment. Sperm count, motility and semen volume were recorded according to standard WHO reference guidelines and correlated with PLCζ profiles examined via immunoblotting and immunofluorescence. Appropriate fertility treatments were performed following routine clinical standard operating protocols, and fertilisation success determined by successful observation of second polar body extrusion. Results and Discussion Four distinct PLCζ patterns were observed at the equatorial, acrosomal + equatorial regions of the sperm head, alongside a dispersed pattern, and a population of spermatozoa without any PLCζ. Acrosomal + equatorial PLCζ correlated most to sperm health, while dispersed PLCζ correlated to decreased sperm viability. Total levels of PLCζ exhibited significant correlations with sperm parameters. PLCζ variance corresponded to reduced sperm health, potentially underlying cases of male sub‐fertility and increasing male age. Finally, significantly higher levels of PLCζ were exhibited by cases of fertilisation success, alongside higher proportions of Ac + Eq, and lower levels of dispersed PLCζ. Conclusions PLCζ potentially represents a biomarker of sperm health, and fertilisation capacity in general cases of patients seeking fertility treatment, and not just cases of repeated fertilisation. Further focused investigations are required with larger cohorts to examine the full clinical potential of PLCζ.
Pluripotent stem cells (PSCs) lie at the heart of modern regenerative medicine due to their properties of unlimited self-renewal and their ability to differentiate into cell types representative of the three embryonic germ layers-mesoderm, ectoderm and endoderm. The derivation of induced PSCs bypasses ethical concerns associated with the use of human embryonic stem cells and also enables personalized cell-based therapies. To exploit their regenerative potential, it is essential to have a firm understanding of the molecular processes associated with their induction from somatic cells. This understanding serves two purposes: first, to enable efficient, reliable and cost-effective production of excellent quality induced PSCs and, second, to enable the derivation of safe, good manufacturing practice-grade transplantable donor cells. Here, we review the reprogramming process of somatic cells into induced PSCs and associated mechanisms with emphasis on self-renewal, epigenetic control, mitochondrial bioenergetics, sub-states of pluripotency, naive ground state, naive and primed. A meta-analysis identified genes expressed exclusively in the inner cell mass and in the naive but not in the primed pluripotent state. We propose these as additional biomarkers defining naive PSCs.This article is part of the theme issue 'Designer human tissue: coming to a lab near you'.
Sperm-specific phospholipase C zeta (PLCζ) initiates intracellular calcium (Ca2+) transients which drive a series of concurrent events collectively termed oocyte activation. Numerous investigations have linked abrogation and absence/reduction of PLCζ with forms of male infertility in humans where oocyte activation fails. However, very few studies have examined potential relationships between PLCζ and advancing male age, both of which are increasingly considered to be major effectors of male fertility. Initial efforts in humans may be hindered by inherent PLCζ variability within the human population, alongside a lack of sufficient controllable repeats. Herein, utilizing immunoblotting, immunofluorescence, and quantitative reverse transcription PCR (qRT-PCR) we examined for the first time PLCζ protein levels and localization patterns in sperm, and PLCζ mRNA levels within testes, from mice at 8 weeks, 12 weeks, 24 weeks, and 36 weeks of age, from two separate strains of mice, C57BL/6 (B6; inbred) and CD1 (outbred). Collectively, advancing male age generally diminished levels and variability of PLCζ protein and mRNA in sperm and testes, respectively, when both strains were examined. Furthermore, advancing male age altered the predominant pattern of PLCζ localization in mouse sperm, with younger mice exhibiting predominantly post-acrosomal, and older mice exhibiting both post-acrosomal and acrosomal populations of PLCζ. However, the specific pattern of such decline in levels of protein and mRNA was strain-specific. Collectively, our results demonstrate a negative relationship between advancing male age and PLCζ levels and localization patterns, indicating that aging male mice from different strains may serve as useful models to investigate PLCζ in cases of male infertility and subfertility in humans.
Mammalian oocyte activation is initiated by intracellular calcium (Ca2+) oscillations, driven by the testis-specific phospholipase C zeta (PLCζ). Sperm PLCζ analysis represents a diagnostic measure of sperm fertilisation capacity. The application of antigen unmasking/retrieval (AUM) generally enhanced the visualisation efficacy of PLCζ in mammalian sperm, but differentially affected the PLCζ profiles in sperm from different human males. It is unclear whether AUM affects the diagnosis of PLCζ in human sperm. Herein, we examined whether the application of AUM affected the correlation of PLCζ profiles with sperm parameters and fertilisation capacity. PLCζ fluorescence levels and localisation patterns were examined within the sperm of males undergoing fertility treatment (55 patients aged 29–53) using immunofluorescence in the absence/presence of AUM. The changes in PLCζ profiles following AUM were examined in relation to sperm health and fertilisation outcome. AUM enhanced the observable levels and specific localisation patterns of PLCζ in relation to both optimal sperm parameters and fertilisation outcome, without which significant differences were not observed. The extent of the change in levels and localisation ratios of PLCζ was also affected to a larger degree in terms of the optimal parameters of sperm fertility and fertilisation capacity by AUM. Collectively, AUM was essential to accurately assesses PLCζ in human sperm in both scientific and clinical contexts.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.