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Men and women become infertile with age, but the mechanism of declining male fertility, more specifically, the decrease in in sperm quality, is not well known. Citrate synthase (CS) is a core enzyme of the mitochondrial tricarboxylic acid (TCA) cycle, which directly controls cellular function. Extra-mitochondrial CS (eCS) is produced and abundant in the sperm head; however, its role in male fertility is unknown. We investigated the role of eCS in male fertility by producing eCs-deficient (eCs-KO) mice. The initiation of the first spike of Ca oscillation was substantially delayed in egg fused with eCs-KO sperm, despite normal expression of sperm factor phospholipase C zeta 1. The eCs-KO male mice were initially fertile, but the fertility dropped with age. Metabolomic analysis of aged sperm revealed that the loss of eCS enhances TCA cycle in the mitochondria with age, presumably leading to depletion of extra-mitochondrial citrate. The data suggest that eCS suppresses age-dependent male infertility, providing insights into the decline of male fertility with age.
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http://dx.doi.org/10.1038/s41374-019-0353-3 | DOI Listing |
Mol Genet Genomic Med
September 2025
Department of Maternal-Fetal Medicine, Augusta University, Augusta, Georgia, USA.
Introduction: Spinal muscular atrophy (SMA), caused by pathogenic variants in the survival motor neuron (SMN) gene, is the most common genetic cause of mortality in children under the age of two. Prior reports of obstetric sonograms performed in pregnancies with severe forms of fetal SMA have discrepant findings that may stem from a failure to account for the SMN2 copy number.
Methods: We present a neonate diagnosed with SMA type 0 postnatally (0SMN1/1SMN2 genotype).
Reprod Domest Anim
September 2025
Department of Teaching Veterinary Clinical Complex, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab, India.
The present study was undertaken to assess the effect of kisspeptin supplementation (0.0, 5.0, 10.
View Article and Find Full Text PDFCurr Opin Urol
September 2025
Department of Urology.
Purpose Of Review: Infertility affects approximately 15% of couples, with male factors implicated in more than 50% of cases. Concerns over declining semen quality - evidenced by a more than 50% drop in sperm concentration over four decades - have triggered investigation into modifiable lifestyle and environmental factors. This review summarizes recent evidence on exposures that negatively impact male fertility.
View Article and Find Full Text PDFCell Discov
September 2025
Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China.
Adverse intrauterine environments, such as hyperglycemia, impair sexual reproduction and species continuity, yet the underlying mechanisms remain poorly understood. In this study, we demonstrated that intrauterine hyperglycemia significantly disrupted primordial germ cell (PGC) development, especially in female offspring, thus reducing fertility. Using Oct4-EGFP transgenic mice with intrauterine hyperglycemia exposure, we revealed that hyperglycemia compromised sexually specific chromatin accessibility and DNA methylation reprogramming during PGC development.
View Article and Find Full Text PDFReproduction
October 2025
State Key Laboratory of Reproductive Medicine and Offspring Health, The Affiliated Taizhou People's Hospital of Nanjing Medical University, Taizhou School of Clinical Medicine, Nanjing Medical University, Nanjing, China.
In Brief: Lipid homeostasis is vital for maintaining testicular function and male fertility, but the specific contributions of lipid-regulating enzymes remain unclear. This study shows that DGKη, although highly expressed in the testis, is not essential for spermatogenesis but modulates testicular lipid metabolism in response to dietary conditions.
Abstract: Diacylglycerol kinase eta (DGKη), encoded by the Dgkh gene, catalyzes the phosphorylation of diacylglycerol to phosphatidic acid, both of which are key lipid second messengers.