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Spermatogenesis is the process of generation of male reproductive cells from spermatogonial stem cells in the seminiferous epithelium of the testis. During spermatogenesis, key spermatogenic events such as stem cell self-renewal and commitment to meiosis, meiotic recombination, meiotic sex chromosome inactivation, followed by cellular and chromatin remodeling of elongating spermatids occur, leading to sperm cell production. All the mentioned events are at least partially controlled by the epigenetic modifications of DNA and histones. Additionally, during embryonal development in primordial germ cells, global epigenetic reprogramming of DNA occurs. In this review, we summarized the most important epigenetic modifications in the particular stages of germ cell development, in DNA and histone proteins, starting from primordial germ cells, during embryonal development, and ending with histone-to-protamine transition during spermiogenesis.

Salivary gland tumors are highly variable in clinical presentation and histology. The World Health Organization (WHO) classifies 22 types of malignant and 11 types of benign tumors of the salivary glands. Diagnosis of salivary gland tumors is based on imaging (ultrasound, magnetic resonance imaging) and fine-needle aspiration biopsy, but the final diagnosis is based on histopathological examination of the removed tumor tissue. In this pilot study, we are testing a new approach to identifying peptide biomarkers in saliva that can be used to diagnose salivary gland tumors. The research material for the peptidomic studies was extracts from washings of neoplastic tissues and healthy tissues (control samples). At the same time, saliva samples from patients and healthy individuals were analyzed. The comparison of the peptidome composition of tissue extracts and saliva samples may allow the identification of potential peptide markers of salivary gland tumors in patients’ saliva. The peptidome compositions extracted from 18 tumor and 18 healthy tissue samples, patients’ saliva samples (11 samples), and healthy saliva samples (8 samples) were analyzed by LC-MS tandem mass spectrometry. A group of 109 peptides was identified that were present only in the tumor tissue extracts and in the patients’ saliva samples. Some of the identified peptides were derived from proteins previously suggested as potential biomarkers of salivary gland tumors (ANXA1, BPIFA2, FGB, GAPDH, HSPB1, IGHG1, VIM) or tumors of other tissues or organs (SERPINA1, APOA2, CSTB, GSTP1, S100A8, S100A9, TPI1). Unfortunately, none of the identified peptides were present in all samples analyzed. This may be due to the high heterogeneity of this type of cancer. The surprising result was that extracts from tumor tissue did not contain peptides derived from salivary gland-specific proteins (STATH, SMR3B, HTN1, HTN3). These results could suggest that the developing tumor suppresses the production of proteins that are essential components of saliva.

Abstract Context The hypothalamic-pituitary-gonadal axis's transient activity in infancy, i.e, minipuberty, is considered crucial for male reproductive function. Historically, minipuberty has been considered a passive response triggered by the withdrawal of placental steroids at birth. However, given its potential link to adult reproductive function, we hypothesize that minipuberty is a partially genetically regulated process, suggesting a link between the genetic architecture of reproductive hormone concentrations across lifespan. Objective To investigate the association of UK Biobank Study-based polygenic scores (PGS) of adult total testosterone (T) and sex hormone-binding globulin (SHBG) concentrations with trajectories of reproductive hormones concentrations in male infants. Design Prospective, longitudinal birth cohort (The COPENHAGEN Minipuberty Study, 2016-2018, ClinTrial: NCT02784184). Individual PGSs in male infants derived from published literature were calculated for total T and SHBG. The associations with mean SD scores (SDS) of reproductive hormone concentrations in infancy were tested. Setting Population-based. Patients or other participants Healthy, male, term, singleton newborns were followed with repeated clinical examinations including blood sampling during a 1-year follow-up (n = 109). Main outcome measures Circulating reproductive hormone concentrations. Results T-PGSadult were significant associated with mean T-SDSinfancy, mean SHBG-SDSinfancy, and mean LH-SDSinfancy (P = .02, <.001 and .03, with r2 = 0.05, 0.21 and 0.04, respectively). SHBG-PGSadult was significantly associated with mean SHBG-SDSinfancy (P < .001, r2 = 0.18). T-PGSadult explained 5% and 21% of the phenotypic variation in infancy of mean T-SDSinfancy and SHBG-SDSinfancy, respectively. Conclusion Our findings suggest that the genetic architecture underlying total T and SHBG in adults also associates with hormone concentrations and their trajectories during infancy.

Résumé La spermatogenèse est le processus de génération de cellules reproductrices mâles à partir de cellules souches spermatogoniales, dans l’épithélium séminifère du testicule. Au cours de la spermatogenèse, des événements spermatogéniques clés tels que l’auto-renouvellement des cellules souches et l’engagement dans la méiose, la recombinaison méiotique, l’inactivation méiotique du chromosome sexuel, suivis d’un remodelage cellulaire et chromatique des spermatides allongées se produisent, conduisant à la production de spermatozoïdes. Tous les événements mentionnés sont au moins partiellement contrôlés par les modifications épigénétiques de l’ADN et des histones. De plus, au cours du développement embryonnaire, une reprogrammation épigénétique globale de l’ADN se produit dans les cellules germinales primordiales. Dans cette revue, nous avons résumé les modifications épigénétiques les plus importantes dans les étapes particulières du développement des cellules germinales, dans l’ADN et les protéines histones, en partant des cellules germinales primordiales, au cours du développement embryonnaire, jusqu’à la transition histone-protamine pendant la spermiogenèse.