Transforming Growth Factor-β2 Induces Synthesis and Secretion of Endothelin-1 in Human Trabecular Meshwork Cells
| Autor: | Kelly A. Langert, Cynthia L. Von Zee, Evan B. Stubbs |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
medicine.medical_specialty
Pyridines Enzyme-Linked Immunosorbent Assay Biology Real-Time Polymerase Chain Reaction Filamentous actin Transforming Growth Factor beta2 Trabecular Meshwork Internal medicine Cadaver medicine Humans Secretion Benzodioxoles Lovastatin RNA Messenger Receptor Cell Line Transformed Analysis of Variance Endothelin-1 Imidazoles Endothelin 1 Molecular biology Actins Recombinant Proteins medicine.anatomical_structure Endocrinology Cell culture Trabecular meshwork Signal transduction Signal Transduction Transforming growth factor |
| Zdroj: | Investigative Opthalmology & Visual Science. 53:5279 |
| ISSN: | 1552-5783 |
| Popis: | Purpose Analysis of aqueous humor from patients with primary open-angle glaucoma (POAG) revealed marked increases in the content of endothelin-1 (ET-1) and transforming growth factor-beta (TGF-β). We determined the consequences of TGF-β signaling on ET-1 expression and secretion by human trabecular meshwork (TM) cells. Methods Primary or transformed (NTM5 and GTM3) human TM cells conditioned in serum-free media were incubated in the absence or presence of TGF-β1 or -β2. Relative changes in preproendothelin (ppET)-1 mRNA content and secreted ET-1 peptide were quantified by real-time PCR and ELISA, respectively. In some experiments, TGF-β or ET-1 receptor antagonists, or Rho G-protein inhibitors, were evaluated for effects on TGF-β signaling. Filamentous actin organization was visualized by phalloidin. Results Primary or transformed human TM cells cultured in the presence of TGF-β1 or -β2 exhibit a marked (>8-fold) increase in ppET-1 mRNA content compared to vehicle controls. Coincubation with SB-505124, an inhibitor of TGFβRI/ALK-5 signaling, prevented TGF-β-mediated ppET-1 mRNA expression. In contrast, coincubation with ET(A) (BQ-123) or ET(B) (BQ-788) receptor antagonists had no effect on TGF-β-mediated ppET-1 mRNA expression. TGF-β1 and -β2 each elicited a robust (>7-fold) secretion of ET-1 while enhancing stress fiber organization. Inhibition of Rho signaling attenuated TGF-β-mediated increases in ppET-1 mRNA content, ET-1 secretion, and stress fiber organization. Conclusions TGF-β, signaling through the TGFβRI/ALK-5 receptor, elicits marked increases in ET-1 mRNA content and ET-1 secretion from cultured primary or transformed human TM cells. Elevated levels of TGF-β2 present in AH of POAG patients may elevate intraocular pressure, in part, by eliciting aberrant Rho G-protein dependent cell contraction, and increasing ET-1 synthesis and secretion, in human TM cells. |
| Databáze: | OpenAIRE |
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