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Abstract #45448 Published in IGR 13-2
Coordinated Regulation of Extracellular Matrix Synthesis by the MicroRNA-29 Family in the Trabecular Meshwork
Villarreal G Jr; Oh DJ; Kang MH; Rhee DJInvestigative Ophthalmology and Visual Science 2011;
Purpose. The microRNA-29 (miR-29) family has emerged, in various tissues, as a key modulator of extracellular matrix (ECM) homeostasis. In this study, we 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 h. 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. While 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 insights into the complex regulatory mechanisms mediating TGF-β2 signaling and ECM production in the TM.
Department of Ophthalmology, Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA.
Classification:
2.5.1 Trabecular meshwork (Part of: 2 Anatomical structures in glaucoma > 2.5 Meshwork)
3.6 Cellular biology (Part of: 3 Laboratory methods)
