Pharmacological perturbation of peroxisome-proliferator-activated receptor gamma alters motility and mitochondrial function of bovine sperm

High-resolution LC-MS/MS combined with TMT quantitative proteomic analysis reveals regulatory mechanism of sperm capacitation by heparin, Ca2+ and BSA

Heparin, BSA, and CaCl2 have been demonstrated to induce sperm capacitation in vitro; however, the specific molecular mechanisms by which different chemokines regulate sperm capacitation remain incompletely elucidated. In previous studies, our laboratory utilized various chemokines to induce capacitation in porcine sperm in vitro and classified these chemokines into three categories based on changes in olfactory receptors. Therefore, this study aims to systematically investigate the molecular pathways and regulatory mechanisms underlying heparin, CaCl2, and BSA induced porcine sperm capacitation. Porcine sperm were treated with heparin, CaCl2, or BSA for 1-4 h, and capacitation was assessed by measuring mitochondrial membrane potential (MMP), intracellular Ca2+ concentration, and capacitation rate. Differential protein expression among the three groups was analyzed using TMT-based quantitative proteomics. The results demonstrated that heparin, CaCl2, and BSA significantly increased intracellular Ca2+ concentration in a time-dependent manner, reduced MMP, and successfully induced sperm capacitation. Proteomic analysis revealed that differentially expressed proteins between the heparin and BSA groups were primarily enriched in lipid metabolism-related signaling pathways, such as PPAR and AMPK, while differentially expressed proteins in the CaCl2 group were significantly enriched in B vitamin metabolic pathways, including riboflavin and nicotinic acid metabolism. Furthermore, olfactory receptors OR1J4 and OR4C13 were found to specifically bind chemokines and participate in the regulation of sperm capacitation. In conclusion, this study elucidates the distinct molecular mechanisms by which heparin, CaCl2, and BSA induce porcine sperm capacitation and provides the first evidence of the critical role of olfactory receptors OR1J4 and OR4C13 in regulating sperm capacitation, offering new theoretical insights into the molecular mechanisms underlying sperm capacitation.

Birth weight, growth indices, and seminal parameters in male offspring are resilient features to maternal pre-conceptional dietary manipulation in sheep

Gestational diet manipulation can lead to inadequate fetal nutrient supply resulting in low birth weight, limited postnatal growth, and consequently, reduced reproductive performance in the progeny. However, effects of short-term maternal pre-conceptional dietary manipulation on postnatal growth and reproductive parameters of male offspring in large animals remains unexplored. To determine these consequences, female crossbred (Polypay x Dorset) sheep were allocated to three groups (n = 33/group) of dietary manipulation for 21 days prior to mating under the following conditions: (1) control at 100 % of maintenance energy requirements (40 Kcal of metabolizable energy/kg body weight [BW]), (2) undernutrition (UN) at 50 % of Control intake, and (3) overnutrition (ON) at 200 % of maintenance energy. Singleton ram lambs (UN:9; C:12; ON:6) were monitored from birth until 8 months of age, including birth weight, weekly weights, weight gain, body mass index (BMI), and circulating testosterone. After weaning, monthly scrotal circumference and subcutaneous fat depth were measured. Semen morphology and motility were evaluated at 7 and 8 months of age. Birth weight, weight gain, and BMI at birth and weaning were not significantly different among nutritional treatments. None of the pre-conceptional diets affected body weight change from weaning until 36 weeks of age, BMI, fat depth, or scrotal circumference across the experiment. A sustained rise in plasma testosterone concentrations was detected when ram lambs were, on average, 82 days old and 37 kg. Both testosterone concentrations and scrotal circumference were positively correlated to body weight regardless of treatment group. In addition, seminal parameters did not differ among treatments, but a transient increase in plasma testosterone at 18 weeks of age was observed in ON ram lambs compared to control rams. In conclusion, birth weight, growth indices, and seminal parameters in singleton rams are resilient features in the progeny upon maternal pre-conceptional dietary manipulation in sheep.