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Role of lysophospholipid growth factors in the modulation of aqueous humor outflow facility.

Publication ,  Journal Article
Mettu, PS; Deng, P-F; Misra, UK; Gawdi, G; Epstein, DL; Rao, PV
Published in: Invest Ophthalmol Vis Sci
July 2004

PURPOSE: To investigate the role of lysophospholipid growth factors in the regulation of aqueous humor outflow in the trabecular meshwork (TM). METHODS: The expression profile of the endothelial differentiation gene (Edg) family of G-protein coupled receptors was determined by RT-PCR of human TM (HTM) cell-derived total RNA and by PCR amplification of HTM cell-derived and tissue-derived cDNA libraries. The effects of lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) on actin cytoskeleton and focal adhesions and on myosin light-chain (MLC) phosphorylation in HTM cells were evaluated by immunofluorescence microscopy and Western blot analysis, respectively. Activation of Rho GTPase in HTM cells was quantified by "pull-down" assays. Mobilization of intracellular calcium in HTM cells was determined using spectrofluorometric digital-imaging microscopy. The effects of LPA and S1P on aqueous humor outflow facility were evaluated by perfusion of enucleated porcine eyes. RESULTS: Each of the receptor isoforms Edg1, -2, -3, and -4 was readily detectable in three of four HTM cell-derived libraries, whereas Edg2 was detectable in the HTM tissue library. LPA (20 microM) and S1P (1 microM) stimulated actin stress fiber and focal adhesion formation, increased MLC phosphorylation, and induced marked activation of Rho GTPase in HTM cells. Both LPA (20 microM) and S1P (10 microM) also stimulated increases in intracellular calcium concentration in HTM cells. LPA- and S1P-induced effects on MLC phosphorylation in HTM cells were markedly inhibited by pretreatment with the Rho kinase-specific inhibitor Y-27632 (5 microM). Perfusion of LPA (50 microM) and S1P (5 microM) in enucleated porcine eyes produced a significant decrease in aqueous humor outflow facility from baseline of 37% (n = 6) and 31% (n = 5), respectively. CONCLUSIONS: These studies demonstrate that LPA and S1P, the physiological agonists of Edg receptors, decrease outflow facility in perfused porcine eyes in association with increased MLC phosphorylation and Rho guanosine triphosphatase (GTPase) activation. These data provide evidence for a novel mechanism for negative regulation of outflow facility, which may contribute to overall physiological homeostasis of aqueous humor outflow facility.

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Published In

Invest Ophthalmol Vis Sci

DOI

ISSN

0146-0404

Publication Date

July 2004

Volume

45

Issue

7

Start / End Page

2263 / 2271

Location

United States

Related Subject Headings

  • rho GTP-Binding Proteins
  • Trabecular Meshwork
  • Swine
  • Sphingosine
  • Spectrometry, Fluorescence
  • Reverse Transcriptase Polymerase Chain Reaction
  • Receptors, Lysophospholipid
  • Receptors, G-Protein-Coupled
  • Phosphorylation
  • Ophthalmology & Optometry
 

Citation

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Chicago
ICMJE
MLA
NLM
Mettu, P. S., Deng, P.-F., Misra, U. K., Gawdi, G., Epstein, D. L., & Rao, P. V. (2004). Role of lysophospholipid growth factors in the modulation of aqueous humor outflow facility. Invest Ophthalmol Vis Sci, 45(7), 2263–2271. https://doi.org/10.1167/iovs.03-0960
Mettu, Priyatham Sai, Pei-Feng Deng, Uma K. Misra, Govind Gawdi, David L. Epstein, and P Vasantha Rao. “Role of lysophospholipid growth factors in the modulation of aqueous humor outflow facility.Invest Ophthalmol Vis Sci 45, no. 7 (July 2004): 2263–71. https://doi.org/10.1167/iovs.03-0960.
Mettu PS, Deng P-F, Misra UK, Gawdi G, Epstein DL, Rao PV. Role of lysophospholipid growth factors in the modulation of aqueous humor outflow facility. Invest Ophthalmol Vis Sci. 2004 Jul;45(7):2263–71.
Mettu, Priyatham Sai, et al. “Role of lysophospholipid growth factors in the modulation of aqueous humor outflow facility.Invest Ophthalmol Vis Sci, vol. 45, no. 7, July 2004, pp. 2263–71. Pubmed, doi:10.1167/iovs.03-0960.
Mettu PS, Deng P-F, Misra UK, Gawdi G, Epstein DL, Rao PV. Role of lysophospholipid growth factors in the modulation of aqueous humor outflow facility. Invest Ophthalmol Vis Sci. 2004 Jul;45(7):2263–2271.

Published In

Invest Ophthalmol Vis Sci

DOI

ISSN

0146-0404

Publication Date

July 2004

Volume

45

Issue

7

Start / End Page

2263 / 2271

Location

United States

Related Subject Headings

  • rho GTP-Binding Proteins
  • Trabecular Meshwork
  • Swine
  • Sphingosine
  • Spectrometry, Fluorescence
  • Reverse Transcriptase Polymerase Chain Reaction
  • Receptors, Lysophospholipid
  • Receptors, G-Protein-Coupled
  • Phosphorylation
  • Ophthalmology & Optometry