title: 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.
abstract: 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.
authors.affiliation: Department of Obstetrics and Gynecology, Chandler Medical Center, University of Kentucky, Lexington, Kentucky 40536-0298, USA. mjo2@uky.edu
authors.forename: Misung
authors.initials: M
authors.lastname: Jo
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Thomas
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Wheeler
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Curry
mesh_terms: 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
chemical_list: 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