Dynamic in vivo changes in the activities of gelatinases, matrix metalloproteinases (MMPs), and tissue inhibitor of metalloproteinases (TIMPs) in buffalo (Bubalus bubalis) uterine luminal fluid during estrous cycle and early pregnancy

Abstract

In ruminants, the phenomenon of endometrial tissue remodeling during the estrous cycle and early pregnancy is not fully understood. In this report, the occurrence of tissue remodeling, if any, in buffalo endometrium was studied by detecting gelatinases, matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs); the key regulators of tissue remodeling, in uterine luminal fluids (ULF) of cycling and early pregnant (approx. 43-65 days) buffaloes. Each stage of the estrous cycle and pregnant ULF demonstrated a unique profile of gelatinase activities compared to serum/follicular fluid, with a major gelatinase band of 60 kDa with highest activity in early-luteal stage. In addition to a 32 kDa uterus-specific gelatinase band detected in both non-pregnant and pregnant ULFs, the pregnant ULF displayed three new gelatinase bands of 86, 78, and 57 kDa. Western blot technique confirmed the presence of MMP-2 (54 kDa), MMP-9 (76/73 kDa), TIMP-1 (32 kDa), TIMP-2(20 kDa), and two molecular weight forms (31 and 22 kDa) of TIMP-3 in buffalo ULF with varying band intensities. Highest MMP-2 and MMP-9 activities were observed in follicular and early-luteal stage ULFs, respectively. Highest TIMP-1 activity was observed in early-luteal ULF. Interestingly, TIMP-2 activity was only detected in mid-luteal, late-luteal, and follicular stage ULFs with significantly increasing intensities. Highest activities of 31 and 22 kDa TIMP-3 were associated with late-luteal and early-luteal stage ULFs, respectively. The varied activities of MMPs and TIMPs in buffalo ULF during the estrous cycle and early pregnancy might be a reflection of dynamic structural remodeling of the endometrium and/or developing conceptus.

Segment­Specific Expression of MMP/TIMP in the Oviduct of Llama (Lama glama) and Gelatinolytic Activity in the Oviductal Fluid

“…In our opinion, the 79 and 72 kDa proteins are active MMP9 isoforms. These data are in agreement with a previous study that reported the presence a 94 kDa band in llama OF (Zampini et al) and by Roy & Ghosh (2010) who described two MMP9 active isoforms in buffalo uterine fluid, that are coincident with the molecular weight observed in llama OF. Similar to llama MMP2, these findings suggest that MMP9 is not continuously active in the oviductal lumen; probably, it experiments a temporal and site-specific activation.…”

Matrix Metalloproteinases in Normal Pregnancy and Preeclampsia

“…102 Also, the matrilysin MMP-7 could play a role in endometrial tissue remodeling during the menstrual cycle and pregnancy. 103 Studies have also shown that cytotrophoblasts and VSM release MMP-12, which could mediate elastolysis and remodeling of the uterine spiral arteries during pregnancy. 104 Whether the uteroplacental and vascular MMP balance is altered in hypertension in pregnancy is a subject of topical interest.…”

Cellular uptake of proMMP-2:TIMP-2 complexes by the endocytic receptor megalin/LRP-2

“…Moreover, several MMPs and TIMPs, including MMP-2, MMP-9 and TIMP-2, are present in the semen 33, 34 . Furthermore, MMPs are found in the uterine fluid of buffalo 35 and TIMP-4, an inhibitor of MMP-2 and MMP-9, is released into the uterine fluid 36 . Interestingly, megalin/LRP-2 is localized at the apical surface of the glands and surface epithelium in human endometrium 37 and consequently is in contact of both semen and uterine fluids.…”