Glycodelin: A Major Lipocalin Protein of the Reproductive Axis with Diverse Actions in Cell Recognition and Differentiation

Abstract

Glycodelin is a glycoprotein that belongs to the lipocalin superfamily. Depending on glycosylation, glycodelin appears in various isoforms. In the uterus, glycodelin-A is the major progesterone-regulated glycoprotein secreted into uterine luminal cavity by secretory/decidualized endometrial glands. The other tissues expressing glycodelin include fallopian tubes, ovary, breast, seminal vesicle, bone marrow, and eccrine glands. Glycodelin-A potently and dose-dependently inhibits human sperm-egg binding, whereas differently glycosylated glycodelin-S from seminal plasma has no such effect. Absence of contraceptive glycodelin-A in the uterus during periovulatory midcycle is consistent with an open "fertile window." Glycodelin induced by local or systemic administration of progestogens may potentially reduce the fertilizing capacity of sperm in any phase of the menstrual cycle. Glycodelin also has immunosuppressive activity. Its high concentration at the fetomaternal interface may contribute to protection of the embryonic semiallograft. Besides being an epithelial differentiation marker, glycodelin appears to play a role in glandular morphogenesis, as transfection of glycodelin cDNA into a glycodelin-negative breast cancer cells resulted in formation of gland-like structures, restricted proliferation, and induction of other epithelial markers. These various properties, as well as the chemistry, biology, and clinical aspects of glycodelin, continue to be areas of active investigation reviewed in this communication.

Binding of Zona Binding Inhibitory Factor-1 (ZIF-1) from Human Follicular Fluid on Spermatozoa

“…Fig. 8), consistent with previous observation (2,8). Progesterone induced acrosome reaction in spermatozoa incubated in EBSS/BSA only (Fig.…”

“…There are two known isoforms of glycodelin, amniotic fluid glycodelin (glycodelin-A, GdA) and seminal plasma glycodelin (glycodelin-S, GdS). The two isoforms have identical protein backbones but have different glycosylation processes (5)(6)(7)(8). Only glycodelin-A has spermatozoa zona pellucida binding inhibitory activity (9), whereas glycodelin-S does not affect spermatozoa zona binding (5,10).…”

“…They have similar molecular size: 28 kDa for glycodelin-A (8, 12) and 32 kDa for ZIF-1 (4). Both are found in follicular fluid of women undergoing assisted reproduction treatment (2,4,8,12) and inhibit the binding of human spermatozoa to zona pellucida (4,9) in a dose-dependent manner. Neither of the glycoproteins affects the motility and spontaneous acrosome reaction of spermatozoa in vitro (2,4,9).…”

Molecular mechanisms of membrane interaction at implantation

“…Glycodelin A (GdA) is reportedly one of the most abundant glycoproteins in the secretory and decidualized endometrium, and is thought to play a vital role in preparing the endometrium for implantation (Seppala et al, 2002;Uchida et al, 2007). During pregnancy, levels of GdA production in the decidua increases.…”

Uterine and Serum Glycodelin Concentration in Recurrent Implantation Failure Versus Normal Fertile Women on Implantation Window

“…It is being thought that severe military conflicts in Africa shorten the expected lifetime for more than 2 years. In general, WHO had calculated that 269 thousand people had died in 1999 due to the effect of wars and that loss of 8.44 million healthy years of life had occurred (2,3). Wars negatively affect the provision of health services.…”