June 2015
Volume 56, Issue 7
Free
ARVO Annual Meeting Abstract  |   June 2015
Constitutive Expression and Release of TGF-β2 by Human Trabecular Meshwork Cells
Author Affiliations & Notes
  • Cynthia Lynn Pervan
    Research Service (151), Edward Hines Jr. VA Hospital, Hines, IL
    Ophthalmology, Loyola University Chicago, Maywood, IL
  • Jonathan D Lautz
    Research Service (151), Edward Hines Jr. VA Hospital, Hines, IL
    Program in Neuroscience, Loyola University Chicago, Maywood, IL
  • Andrea L Blitzer
    Research Service (151), Edward Hines Jr. VA Hospital, Hines, IL
    Stritch School of Medicine, Loyola University Chicago, Maywood, IL
  • Evan B Stubbs
    Research Service (151), Edward Hines Jr. VA Hospital, Hines, IL
    Ophthalmology, Loyola University Chicago, Maywood, IL
  • Footnotes
    Commercial Relationships Cynthia Pervan, None; Jonathan Lautz, None; Andrea Blitzer, None; Evan Stubbs, None
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science June 2015, Vol.56, 3295. doi:
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    • Get Citation

      Cynthia Lynn Pervan, Jonathan D Lautz, Andrea L Blitzer, Evan B Stubbs; Constitutive Expression and Release of TGF-β2 by Human Trabecular Meshwork Cells. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):3295.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose: Irreversible loss of peripheral vision in patients with primary open-angle glaucoma (POAG) is closely associated with increased intraocular pressure (IOP). Although the cause of POAG remains unclear, elevated levels of TGF-β2 in aqueous humor (AH) of affected patients is strongly implicated in the pathophysiology of enhanced AH outflow resistance. However, the mechanism responsible for, and the cellular origin of, elevated TGF-β2 in AH remains poorly defined. Here, we investigated whether human TM cells endogenously express and secrete biologically-active TGF-β2.

Methods: Primary or transformed (GTM3) human TM cells were incubated x24h in the absence or presence of chemically-activated lovastatin (10 µM), GGTI-298 (an inhibitor of geranylgeranyl transferase-I; 20 µM), or exoenzyme C3 transferase (10 µM). Constitutive TGF-β2 mRNA or biologically-active protein secretion was quantified by qRT-PCR or ELISA analysis, respectively. Stabilized porcine anterior segments (n = 5 pairs) were perfused in the absence or presence of SB-431542 (a TGFβRI/ALK-5 antagonist; 1 µM) and IOP quantified every 3 minutes for up to 48h.

Results: Quiescent GTM3 cells expressed measurable quantities of TGF-β2 mRNA while constitutively secreting biologically-active TGF-β2 into the culture medium. Endogenous TGF-β2 expression was markedly reduced by lovastatin, as compared to vehicle controls. Incubation with GGTI-298 mimicked the effect of lovastatin in both primary and transformed human TM cells, eliciting a 60-70% decrease in TGF-β2 mRNA content and a 70-100% reduction in secreted active TGF-β2 protein. Incubation with C3 exoenzyme resulted in a 90% reduction of TGF-β2 mRNA content, and a 40% attenuation of active TGF-β2 secretion, strongly implicating a role for the Rho GTPase subfamily (RhoA/B/C) in regulating constitutive TGF-β2 expression. Importantly, perfusing hypertensive porcine anterior segments with SB-505124 reduced, by 50%, IOP by 15h post-infusion.

Conclusions: We demonstrate for the first time that human TM cells endogenously express and secrete biologically-active TGF-β2. Constitutive expression/release of TGF-β2 in human TM cells is regulated, in part, by the Rho subfamily GTPase signaling pathways. We propose that human TM cells serve as a novel local source of functionally active TGF-β2.

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