June 2013
Volume 54, Issue 15
Free
ARVO Annual Meeting Abstract  |   June 2013
Peptide and Non-Peptide Bradykinin (BK) Agonists and Antagonists Help Define Functional BK Receptors in Human Trabecular Meshwork and Ciliary Body
Author Affiliations & Notes
  • Naj Sharif
    Ophthalmology Research, Alcon Research, Ltd-Novartis Institute of Biomedical Research (NIBR), Fort Worth, TX
  • Parvaneh Katoli
    Ophthalmology Research, Alcon Research, Ltd-Novartis Institute of Biomedical Research (NIBR), Fort Worth, TX
  • Curtis Kelly
    Ophthalmology Research, Alcon Research, Ltd-Novartis Institute of Biomedical Research (NIBR), Fort Worth, TX
  • Linya Li
    Ophthalmology Research, Alcon Research, Ltd-Novartis Institute of Biomedical Research (NIBR), Fort Worth, TX
  • Shouxi Xu
    Ophthalmology Research, Alcon Research, Ltd-Novartis Institute of Biomedical Research (NIBR), Fort Worth, TX
  • Yu Wang
    Ophthalmology Research, Alcon Research, Ltd-Novartis Institute of Biomedical Research (NIBR), Fort Worth, TX
  • Ganesh Prasanna
    Ophthalmology Research, Alcon Research, Ltd-Novartis Institute of Biomedical Research (NIBR), Fort Worth, TX
  • Keith Combrink
    Ophthalmology Research, Alcon Research, Ltd-Novartis Institute of Biomedical Research (NIBR), Fort Worth, TX
  • Mark Hellberg
    Ophthalmology Research, Alcon Research, Ltd-Novartis Institute of Biomedical Research (NIBR), Fort Worth, TX
  • Shahid Husain
    Ophthalmology, Medical University of S. Carolina, Charlston, SC
  • Footnotes
    Commercial Relationships Naj Sharif, Alcon Research, Ltd (a Novartis Co.) (E); Parvaneh Katoli, Alcon Labs (E); Curtis Kelly, Alcon / Novartis Institutes for Biomedical Research (E); Linya Li, Alcon Labs (E); Shouxi Xu, Alcon, Novartis (E); Yu Wang, Novartis, Alcon (E); Ganesh Prasanna, Alcon Research Ltd (E), Novartis Institute of Biomedical Research (E); Keith Combrink, Novartis (E); Mark Hellberg, NIBR (E), Alcon (P); Shahid Husain, None
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science June 2013, Vol.54, 1997. doi:
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      Naj Sharif, Parvaneh Katoli, Curtis Kelly, Linya Li, Shouxi Xu, Yu Wang, Ganesh Prasanna, Keith Combrink, Mark Hellberg, Shahid Husain; Peptide and Non-Peptide Bradykinin (BK) Agonists and Antagonists Help Define Functional BK Receptors in Human Trabecular Meshwork and Ciliary Body. Invest. Ophthalmol. Vis. Sci. 2013;54(15):1997.

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

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Abstract

Purpose: 1) to examine bradykinin (BK) receptor system in human trabecular meshwork (h-TM), human ciliary muscle (h-CM) and ciliary process (CP) by immunohistochemistry; 2) to pharmacologically characterize the associated signaling mechanisms in isolated cells from these tissues using peptide and non-peptide BK agonists (Compounds 1 & 2) and antagonists; 3) to study the intraocular pressure (IOP)-lowering effects of Compound 1 (CMPD-1)

Methods: Published methods were utilized throughout

Results: Human and Cynomolgus monkey TM, CM and CP expressed a high level of B2-receptor protein immunoreactivity. In isolated h-TM, h-CM and human non-pigmented epithelial (h-NPE) cells, BK and related analogs (e.g. Lys-BK; Hyp3-BK) exhibited a high potency (EC50 = 2-8 nM, n = 3-6), while Des-Arg9-BK (B1-receptor agonist) was much weaker (EC50= 4.2 µM), at stimulating intracellular Ca2+ ([Ca2+]i) mobilization. Two non-peptide B2-receptor agonists (CMPD-1 & 2) had lower potencies (CMPD-1 EC50s = 150-276 nM; CMPD-2 EC50s = 25-74 nM; n = 3-29) than BK in these assays. While BK peptides and CMPD-2 were full agonists, CMPD-1 was a partial agonist (Emax = 38% in NPE; 64% in CM; 80% in TM cells). These effects of BK, CMPD-1 & 2 were blocked by HOE-140 (peptide B2-antagonist; Ki = 1-8 nM; n = 4-6) and WIN-63448 (non-peptide B2-antagonist; Ki = 157 - 450 nM, n = 4-5) in all these ocular cells. While h-CM and h-TM cells responded to BK, CMPD-1 & 2 by secreting prostaglandins (PGE2, PGF) (e.g. EC50s = 4 - 61 nM in h-TM cells, n = 3-5; CMPD-1 Emax = 28%), NPE cells failed to release any PGs. The latter PG secretion effects of the BK agonists were also blocked by HOE-140 and WIN-63448, and were attenuated by cyclooxygenase inhibitors (bromfenac and flurbiprofen). BK, CMPD-1 & 2 also increased secretion of Pro-MMP-3 by 1.3-1.6 fold above basal levels in h-CM cells 24 hr post incubation. CMPD-1 lowered IOP in conscious ocular hypertensive Cynomolgus monkeys (e.g. 37.7 ± 5.4% with 30 µg, 24 hrs post topical ocular dosing).

Conclusions: These data support the existence of functionally active B2-receptors in h-TM, h-CM and h-NPE cells that mediate [Ca2+]i mobilization, PG secretion (not in NPE cells) and pro-MMP-3 release (h-CM). These data help explain the potent, efficacious, and prolonged IOP-lowering effects of CMPD-1.

Keywords: 735 trabecular meshwork • 675 receptors: pharmacology/physiology • 457 ciliary processes  
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