title: Coordinated regulation of extracellular matrix synthesis by the microRNA-29 family in the trabecular meshwork.
abstract: OBJECTIVE
  The microRNA-29 (miR-29) family has emerged, in various tissues, as a key modulator of extracellular matrix (ECM) homeostasis. In this study, the authors investigate the role of the miR-29 family in the regulation of ECM synthesis in the trabecular meshwork (TM) under basal and TGF-β2 stimulatory conditions.
  
  
  METHODS
  Human TM cells were incubated with 2.5 ng/mL activated, recombinant human TGF-β2 for 24, 48, and 72 hours. A specific pharmacologic inhibitor was used to block SMAD3 function in the context of TGF-β2 stimulation. Changes in the expression of the miR-29 family were assessed by real-time PCR. The effect of miR-29 molecules and inhibitors on ECM levels was determined by immunoblot analysis.
  
  
  RESULTS
  All three members of the miR-29 family were expressed in cultured TM cells. Although the incubation of TM cells with TGF-β2 induced miR-29a and suppressed miR-29b levels, no significant effect was observed on miR-29c expression. Additional studies revealed that SMAD3 modulates miR-29b expression under basal and TGF-β2 conditions. Subsequent gain- and loss-of-function experiments demonstrated that the miR-29 family functions as a critical suppressor of various ECM proteins under basal and TGF-β2 stimulatory conditions.
  
  
  CONCLUSIONS
  The findings derived from this study identify the miR-29 family as a critical regulator of ECM expression in the TM and suggest that its modulation by TGF-β2 may be important in controlling ECM synthesis. Together, these data provide further insight into the complex regulatory mechanisms mediating TGF-β2 signaling and ECM production in the TM.
authors.affiliation: Department of Ophthalmology, Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, Massachusetts 02114, USA.
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Villarreal
authors.forename: Dong-Jin
authors.initials: DJ
authors.lastname: Oh
authors.forename: Min Hyung
authors.initials: MH
authors.lastname: Kang
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Rhee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002460:Cell Line; D002648:Child; D005109:Extracellular Matrix / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis*; D015870:Gene Expression / Q000502:physiology; D006801:Humans; D015151:Immunoblotting; D007546:Isoquinolines / Q000494:pharmacology; D035683:MicroRNAs / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D008875:Middle Aged; D011725:Pyridines / Q000494:pharmacology; D011758:Pyrroles / Q000494:pharmacology; D011994:Recombinant Proteins / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051900:Smad3 Protein / Q000037:antagonists & inhibitors / Q000378:metabolism; D014019:Tissue Donors; D014129:Trabecular Meshwork / Q000187:drug effects / Q000378:metabolism*; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000494:pharmacology
chemical_list: C508504:6,7-dimethyl-2-(2E)-3-(1-methyl-2-phenyl-1H-pyrrolo(2,3-b)pyridin-3-yl-prop-2-enoyl)-1,2,3,4-tetrahydroisoquinoline hydrochloride; D016326:Extracellular Matrix Proteins; D007546:Isoquinolines; C532045:MIRN29a microRNA, human; D035683:MicroRNAs; D011725:Pyridines; D011758:Pyrroles; D011994:Recombinant Proteins; C497790:SMAD3 protein, human; D051900:Smad3 Protein; D016212:Transforming Growth Factor beta