Membrane type 1-matrix metalloproteinase (MMP)-associated MMP-2 activation increases in the rat ovary in response to an ovulatory dose of human chorionic gonadotropin.
Gonadotropins stimulate ovarian proteolytic enzyme activity that is believed to be important for the remodeling of the follicular extracellular matrix. Membrane type 1-matrix metalloproteinase (MT1-MMP) has been identified in vitro as an activator of pro-MMP-2 by forming a complex with tissue inhibitors of metalloproteinase-2 (TIMP-2). In the present study, the expression pattern of MT1-MMP mRNA and the role of MT1-MMP were examined in the ovary using the gonadotropin-treated immature rat model. Ovaries were collected at selected times after eCG or hCG. RNase protection assays revealed a transient increase in MT1-MMP mRNA beginning 4 h after hCG. High expression of MT1-MMP mRNA was localized to the theca-interstitial layer of developing and preovulatory follicles, while low expression was observed in the granulosa cell layer of developing follicles by in situ hybridization. The localization pattern of MT1-MMP mRNA was compared with TIMP-2 mRNA. Both MMP-2 and TIMP-2 mRNA were expressed in the theca layer of preovulatory follicles, showing a similarity to MT1-MMP mRNA expression. To further determine whether MT1-MMP activates pro-MMP-2 in the ovary, crude plasma membrane fractions from preovulatory ovaries were analyzed by gelatin zymography. In plasma membrane fractions, pro-MMP-2 increased around the time of ovulation. Upon incubation, pro-MMP-2 was activated with the highest levels of activation at 12 h post-hCG. The addition of MT1-MMP antibody or excess TIMP-2 to membrane fractions inhibited pro-MMP-2 activation. The increase in MT1-MMP mRNA may be an important part of the mechanism necessary for the efficient generation of active MMP-2 during the ovulatory process.
Jo
Misung
M
Department of Obstetrics and Gynecology, Chandler Medical Center, University of Kentucky, Lexington, Kentucky 40536-0298, USA. mjo2@uky.edu
Thomas
Lauren E
LE
Wheeler
Sarah E
SE
Curry
Thomas E
TE
D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D006063:Chorionic Gonadotropin / Q000008:administration & dosage* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000378:metabolism; D005260:Female; D005498:Follicular Phase; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism*; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases / Q000235:genetics / Q000378:metabolism*; D006080:Ovarian Follicle / Q000502:physiology; D010053:Ovary / Q000187:drug effects* / Q000201:enzymology* / Q000378:metabolism / Q000502:physiology; D010060:Ovulation; D011555:Pseudopregnancy / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000235:genetics
D006063:Chorionic Gonadotropin; D004792:Enzyme Precursors; D012333:RNA, Messenger; D019716:Tissue Inhibitor of Metalloproteinase-2; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases; D020778:Matrix Metalloproteinase 2