During the last seventy years, studies on mammalian sperm cells have demonstrated the essential role of capacitation, hyperactivation and the acrosome reaction in the acquisition of fertilization ability. These studies revealed the important biochemical and physiological changes that sperm undergo in their travel throughout the female genital tract, including changes in membrane fluidity, the activation of soluble adenylate cyclase, increases in intracellular pH and Ca²⁺ and the development of motility. Sperm are highly polarized cells, with a resting membrane potential of about −40 mV, which must rapidly adapt to the ionic changes occurring through the sperm membrane. This review summarizes the current knowledge about the relationship between variations in the sperm potential membrane, including depolarization and hyperpolarization, and their correlation with changes in sperm motility and capacitation to further lead to the acrosome reaction, a calcium-dependent exocytosis process. We also review the functionality of different ion channels that are present in spermatozoa in order to understand their association with human infertility.

Mechanistic target of rapamycin (mTOR) is a master signaling pathway that regulates organismal growth and homeostasis, because of its implication in protein and lipid synthesis, and in the control of the cell cycle and the cellular metabolism. Moreover, it is necessary in cerebellar development and stem cell pluripotency maintenance. Its deregulation has been implicated in the medulloblastoma and in medulloblastoma stem cells (MBSCs). Medulloblastoma is the most common malignant solid tumor in childhood. The current therapies have improved the overall survival but they carry serious side effects, such as permanent neurological sequelae and disability. Recent studies have given rise to a new molecular classification of the subgroups of medulloblastoma, specifying 12 different subtypes containing novel potential therapeutic targets. In this review we propose the targeting of mTOR, in combination with current therapies, as a promising novel therapeutic approach.

Gaps in knowledge about the epididymal mucosa contribute to the prevalent classification of male idiopathic infertility. Inflammatory triggers, such as infections and autoimmunity, can breach immune privilege, induce anti-sperm antibody (ASA) production, and impair fertility. However, the mechanisms governing ASA production are poorly characterized. Here, using a murine model of epididymitis induced by regulatory T cell (Treg) depletion, we show that the disruption of immunotolerance leads to chronic autoimmunity characterized by the presence of ASA, and distinct testicular and epididymal immune landscapes. These inflammatory features impair sperm function, contribute to epididymal damage, and drive subfertility. Treg depletion induces the formation of tertiary lymphoid structures (TLS) within the epididymis, as indicated by the presence of B and T cell clusters, fibroblasts, and high endothelial venules. Similar autoantibody responses were detected in the seminal plasma of infertile patients, suggesting conserved mechanisms. Thus, we provide an in-depth analysis of immune cell dynamics and TLS during epididymitis, offering insights for the development of precision-targeted therapies for fertility disorders, as well as the identification of new contraceptive strategies.

Alterazio kromosomikoak dituzten espermatozoideak identifikatzeko biomarkatzaileen hautaketa produkzioaren informazio-fitxa

Morfinak hipometilazio globala eragiten du mES zeluletan autoerregulazioa daukan demetilazio aktibo baten bidez produkzioaren informazio-fitxa

1. Background: Human infertility affects approximately 17.5% of the global population, with male factors accounting for nearly half of all cases. The identification of reliable molecular biomarkers is crucial for improving the diagnosis and assessment of male fertility. In this study, we developed and optimized an untargeted high-performance liquid chromatography–electrospray ionization–tandem mass spectrometry (HPLC-ESI-MS/MS) workflow for comprehensive lipidomic and metabolomic profiling of human spermatozoa using only 1.25 million cells per sample. Results: Compared to previous reports, our optimized method achieved unprecedented analytical depth, identifying 473 lipid species and 955 structurally annotated metabolites, corresponding to nearly 7.600-fold improvements in detection efficiency per cell over published approaches. Lipidomic analysis revealed cholesterol, fatty acids, phosphatidylcholines, and phosphatidylethanolamine plasmalogens as the most abundant lipid classes, consistent with the structural complexity of the sperm plasma membrane. Metabolomic profiling showed strong enrichment of lipid-related and steroidogenic pathways, including phospholipid biosynthesis, glycerolipid metabolism and androgen and estrogen metabolism. The integration of lipidomic and metabolomic data highlighted functionally interconnected pathways related to membrane dynamics, energy metabolism, and hormone biosynthesis. Conclusions: Overall, this work establishes a robust, sensitive, and scalable analytical framework enabling high-coverage molecular characterization of spermatozoa from limited sample material, laying the groundwork for future biomarker discovery and clinical applications in male infertility research. One Sentence Summary: Development of a highly sensitive untargeted HPLC-ESI–MS/MS lipidomic and metabolomic workflow that achieves unprecedented molecular coverage from only 1.25 million human spermatozoa, revealing interconnected lipid and metabolic pathways and providing a robust foundation for biomarker discovery in male infertility. Graphical