Male infertility-related molecules involved in sperm-oocyte fusion

Abstract

Male infertility has become a very serious problem in the human reproduction system, but the molecular mechanism of infertility remains largely unknown. Fertilization is the phenomenon in which a sperm and oocyte find each other, interact, and fuse. Sperm-oocyte fusion-related factors on the sperm side play crucial roles in male infertility. For example, IZUMO1 is well-known as a sperm protein essential for fusion of a sperm and oocyte, but its dysfunction or mutation can result in male infertility. Recent studies showed a novel sperm protein named Bactericidal/permeability-increasing protein (BPI), which takes part in the sperm-oocyte fusion process. The complexity and expected redundancy of the factors involved makes the process intricate, with a still poorly understood mechanism, which is difficult to comprehend in full detail. This review summarizes the known molecules involved in the process of sperm-oocyte fusion, mainly focusing on the relevant factors on the sperm side, whose dysregulation may potentially be associated with male infertility. New insights may come from these molecules in this review, can facilitate the development of new treatments of male infertility, and may have a diagnostic value in infertility.

Seasonal variation in equine follicular fluid proteome

“…In this regard, although the function for BPI in FF is still unknown, the presence of BPIFA2 during the ovulatory seasons may be important to protect the female genital tract (e.g., oviduct). Also, few reports have found that BPI is expressed in the testis and epididymis of mice and appears to take part in the process of gamete interactions [42, 43].…”

How cells fuse

“…Disrupted or unbalanced cell fusion in developmental processes is linked to human diseases. Defects in sperm–egg fusion lead to male infertility (Mou and Xie, 2017). Impediments in myoblast fusion can be perinatally lethal in mice and have been associated with some human myopathies (Di Gioia et al, 2017; Sampath et al, 2018).…”

Plant-Produced Mouse-Specific Zona Pellucida 3 Peptide Induces Immune Responses in Mice

“…Contraceptive vaccines evoke an immune response to molecules that have indispensable roles in the reproduction process. Several proteins have been used successfully to reduce the fertility of various animal species, including antigens associated with sperm [ 14 , 15 , 16 ] and oocytes [ 17 , 18 , 19 ], as well as hormones and their receptor proteins [ 20 , 21 ]. The unique specificity of sperm and oocyte proteins makes them ideal candidates for immunocontraceptive vaccines.…”