Dipeptidyl peptidase IV as a differentiation marker of the human endometrial glandular cells

Abstract

To investigate the involvement of membrane-bound peptidases in the human endometrial function, we examined the expression of dipeptidyl peptidase (DPP) IV and its enzyme activity. Immunohistological studies revealed that DPP IV was detected on human endometrial glandular cells and endometrial surface epithelium, but not on endometrial stromal cells or decidual cells in the first trimester of pregnancy. DPP IV expression on glandular cells and surface epithelium was weak in the proliferative phase, began to increase gradually in the early secretory phase, and was strong in mid-to late secretory phase and in the first trimester of pregnancy. DPP IV enzyme activity was detected histochemically in glandular cells and surface epithelium in the mid-secretory phase, and became stronger in the late secretory phase, but was rarely detected in the proliferative phase and early secretory phase. During the first trimester of pregnancy DPP IV enzyme activity in glandular cells and surface epithelium was slightly weaker than in the late secretory phase. Endometrial stromal cells and decidual cells, however, had no detectable DPP IV enzyme activity at any time throughout the menstrual cycle or during the first trimester of pregnancy. These findings indicate that DPP IV is a differentiation marker for glandular cells and surface epithelium and that active DPP IV is present in both areas during the peri-implantation period and thereafter.

Membrane-bound carboxypeptidase-M is expressed on human ovarian follicles and corpora lutea of menstrual cycle and early pregnancy

“…In addition, we found that another membrane-bound aminopeptidase, dipeptidyl peptidase-IV (DPP-IV, EC.3.4.14.5), is expressed on human luteal cells and endometrial glandular cells Imai et al, 1992cImai et al, , 1996. DPP-IV is specific for removing X amino acid (an unspecified amino acid, Xaa)-Pro or -Ala dipeptides from the N-termini of polypeptides and proteins (Flentke et al, 1991).…”

Activation Antigens during the Proliferative and Secretory Phases of Endometrium and Early-Pregnancy Decidua

“…The results of this study are consistent with this expectation. CD26 is the equivalent of the ectopeptidase dipeptidyl peptidase IV [4,5,12] . The alpha chains of human chorionic gonadotropin and sheep prolactin are among the substrates of this enzyme.…”

“…The alpha chains of human chorionic gonadotropin and sheep prolactin are among the substrates of this enzyme. The human chorionic gonadotropin alpha chain is also a component of follicle-stimulating hormone and luteinizing hormone [12,26,27] . So, the existence of CD26 is very probable in endometrium and decidua.…”

“…Like all peptidases, CD26 is a modulator of growth and differentiation and has different molecular forms [6,10] . Peptidases have important roles in implantation [12] . CD26 provides the necessary special microenvironment for implantation by regulating the local concentration of biologically active peptides [10] .…”

“…It is the cofactor of HIV upon its entering of CD4+ T lymphocytes [10,11] . CD26 is also involved in cellular binding to extracellular matrices [12,13] . CD30 is a type I cytokine receptor [14] .…”