Behavior of ACRBP-deficient mouse sperm in the female reproductive tract

TMT-based quantitative N-glycoproteomic analysis reveals glycoprotein protection can improve the quality of frozen bovine sperm

Cryopreservation of bovine semen plays a vital role in accelerating genetic improvement and elite breeding, but it has a detrimental effect on sperm quality, resulting in the decline of the reproductive efficiency. The glycosylation modification of protein has irreplaceable roles in spermatozoa. Herein, the effect of cryopreservation on glycoproteins of bovine spermatozoa has been studied for the first time using a tandem mass tag (TMT)-labeled quantitative glycoproteome. A total of 2598 proteins and 492 glycoproteins were identified, including 83 different expression proteins (DEPs) and 44 different expression glycosylated proteins (DEGPs) between fresh and frozen spermatozoa. Thirty-three DEPs are glycoproteins, which demonstrates that glycoproteins of bovine sperm were seriously affected by cryopreservation. Moreover, the effects include glycoprotein expression, glycosylation modification, and substructure localization for proteins such as glycoproteins TEX101, ACRBP, and IZOMU4. The biologic functions of the 115 changed proteins are mainly involved in sperm capacitation, migration in female genitalia, and sperm-egg interaction. Mostly key regulators were identified to be glycoproteins, which confirms that glycosylated proteins played important roles in bovine sperm. This comprehensive study of sperm glycoproteins helps to unravel the cryoinjury mechanisms, thus implying that glycoprotein protection should be an effective way to improve the quality of frozen sperm.

Immunohistochemistry Study of OY-TES-1 Location in Fetal and Adult Human Tissues

OY-TES-1 is reportedly involved in carcinogenesis and spermatogenesis. However, the tissue distribution of OY-TES-1 in the normal human body remains elusive. This study detected OY-TES-1 expression in human fetal and adult normal tissues by immunohistochemistry. We identified a general principle of OY-TES-1 expression. The expression of OY-TES-1 was found in neurons, smooth muscle cells, and cardiac muscle cells from both fetuses and adults. The connective tissue showed no specific staining throughout the fetal and adult samples. With OY-TES-1-positive staining of the epithelium irregular, OY-TES-1 was strongly expressed in the epithelium of the skin and bladder, as well as hepatocytes, pancreatic islets, and acinous cells during the fetal stage but was not detected in the postnatal period. In contrast to the epithelium of blood vessels, the fetal and adult central hepatic vein and glomeruli showed negative expression of the OY-TES-1 protein. Sex-dimorphism was observed in the distribution of OY-TES-1 in male and female germ cells. Collectively, our results indicate that OY-TES-1 is a member of the cancer-testis antigen and autoantigen, with tissue-specific and period-specific expression patterns, revealing potential contributions of OY-TES-1 to the diagnosis and therapeutic treatment for neoplasms and infertility.

Improving Sperm Cryopreservation With Type III Antifreeze Protein: Proteomic Profiling of Cynomolgus Macaque (Macaca fascicularis) Sperm

Antifreeze protein III (AFP III) is used for the cryopreservation of germ cells in various animal species. However, the exact mechanism of its cryoprotection is largely unknown at the molecular level. In this study, we investigated the motility, acrosomal integrity, and mitochondrial membrane potential (MMP), as well as proteomic change, of cynomolgus macaque sperm after cryopreservation. Sperm motility, acrosomal integrity, and MMP were lower after cryopreservation (p < 0.001), but significant differences in sperm motility and MMP were observed between the AFP-treated sperm sample (Cryo+AFP) and the non-treated sample (Cryo-AFP) (p < 0.01). A total of 141 and 32 differentially expressed proteins were, respectively, identified in cynomolgus macaque sperm cryopreserved without and with 0.1 μg/ml AFP III compared with fresh sperm. These proteins were mainly involved in the mitochondrial production of reactive oxygen species (ROS), glutathione (GSH) synthesis, and cell apoptosis. The addition of AFP III in the sperm freezing medium resulted in significant stabilization of cellular molecular functions and/or biological processes in sperm, as illustrated by the extent of proteomic changes after freezing and thawing. According to the proteomic change of differentially expressed proteins, we hypothesized a novel molecular mechanism for cryoprotection that AFP III may reduce the release of cytochrome c and thereby reduce sperm apoptosis by modulating the production of ROS in mitochondria. The molecular mechanism that AFP III acts with sperm proteins for cellular protection against cryoinjuries needs further study.