title: Acute effects of PGF2alpha on MMP-2 secretion from human ciliary muscle cells: a PKC- and ERK-dependent process.
abstract: OBJECTIVE
  Studies were designed to evaluate the cellular mechanisms associated with prostaglandin (PG)F(2alpha)-induced matrix metalloproteinase (MMP)-2 secretion from human ciliary muscle (HCM) cells.
  
  
  METHODS
  The secretion and activity of MMP-2 was determined by Western blot analysis and zymography, using conditioned medium and HCM cells. ERK1/2 activity was measured by in-gel kinase assay and Western blot analysis with anti-phospho-ERK1/2 antibodies.
  
  
  RESULTS
  PGF(2alpha) increased the secretion of MMP-2 in a dose-dependent manner with an EC(50) of 2.7 x 10(-8) M. The addition of 1 muM PGF(2alpha) also increased MMP-2 secretion in a time-dependent manner with maximum secretion occurring at 4 hours after administration. At 4 hours, the maximum increase in MMP-2 secretion and activity were 112% +/- 32% and 88% +/- 18%, respectively. The secretory action of PGF(2alpha) was inhibited by pretreatment with a protein kinase C (PKC) inhibitor, chelerythrine chloride; the FP receptor antagonist, AL-8810; and the MEK inhibitor, PD-98059. The addition of PGF(2alpha) and latanoprost acid increased ERK1/2 activity by 117% +/- 12% and 75% +/- 9%, respectively. The PGF(2alpha)- and latanoprost-acid-induced ERK1/2 activation was blocked by the presence of PKC inhibitors and downregulation of PKC by prolonged incubation with a phorbol ester.
  
  
  CONCLUSIONS
  These data provide evidence that FP receptor activation leads to an increase in the secretion and activation of MMP-2 through PKC- and ERK1/2-dependent pathways. FP-agonist-induced activation of ERK1/2 was blocked by PKC inhibitors, indicating that PKC activation is required for ERK1/2 activation and MMP-2 secretion from HCM cells. In the ciliary muscle, the functional responses to ERK1/2 activation include secretion of MMP-2, supporting the hypothesis that increases in uveoscleral outflow facility induced by PG administration involves the secretion and activation of MMP-2.
authors.affiliation: Hewitt Laboratory of the Ola B. Williams Glaucoma Center, Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA.
authors.forename: Shahid
authors.initials: S
authors.lastname: Husain
authors.forename: Farahdiba
authors.initials: F
authors.lastname: Jafri
authors.forename: Craig E
authors.initials: CE
authors.lastname: Crosson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015153:Blotting, Western; D002478:Cells, Cultured; D002924:Ciliary Body / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D015237:Dinoprost / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D000077338:Latanoprost; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D008875:Middle Aged; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D011461:Prostaglandins F, Synthetic / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D011461:Prostaglandins F, Synthetic; D000077338:Latanoprost; D015237:Dinoprost; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020778:Matrix Metalloproteinase 2