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The expression of functionally-coupled B2-bradykinin receptors in human corneal epithelial cells and their pharmacological characterization with agonists and antagonists.
Br J Pharmacol. 1997 Jun; 121(4):649-56.BJ

Abstract

1. Bradykinin (BK) and Lys-BK are peptides which are released at high nanomolar concentrations into the tear-film of ocular allergic patients. We hypothesized that these peptides may activate specific receptors on the ocular surface, especially the corneal epithelium (CE) and thus the CE cells may represent a potential target tissue for these kinins. 2. The purpose of the present studies, therefore, was to determine the presence of and the pharmacological characteristics of bradykinin receptors on normal cultured primary and SV40 virus-transformed human corneal epithelial (CEPI) cells by use of the accumulation of [3H]-inositol phosphates ([3H]-IPs) as a bioassay. 3. Bradykinin (BK) induced a maximal 1.95 +/- 0.24 fold (n = 17) and 2.51 +/- 0.29 fold (n = 26) stimulation of [3H]-IPs accumulation in normal, primary (P-CEPI) and SV40-immortalized (CEPI-17-CL4) cells, respectively. This contrasted with a maximal 3.2-4.5 fold and 2.0-2.9 fold stimulation by histamine (100 microM) and platelet activating factor (100 nM) in both cell-types, respectively. 4. The molar potencies of BK and some of its analogues in the CEPI-17-CL4 cells were as follows: BK (EC50 = 3.26 +/- 0.61 nM, n = 18), Lys-BK (EC50 = 0.95 +/- 0.16 nM, n = 5), Met-Lys-BK (EC50 = 2.3 +/- 0.42 nM, n = 5), Ile-Ser-BK (EC50 = 5.19 +/- 1.23 nM, n = 6), Ala3-Lys-BK (EC50 = 12.7 +/- 2.08 nM, n = 3), Tyr8-BK (EC50 = 19.3 +/- 0.77 nM, n = 3), Tyr5-BK (EC50 = 467 +/- 53 nM, n = 4) and des-Arg9-BK (EC50 = 14.1 +/- 2.7 microM, n = 4). The potencies of BK-related peptides in normal, P-CEPI cells were similar to those found in transformed cells, thus: BK, EC50 = 2.02 +/- 0.69 nM (n = 7), Tyr8-BK, EC50 = 14.6 +/- 2.7 nM (n = 3), Tyr5 = BK, EC50 = 310 +/- 70 nM (n = 4) and des-Arg9-BK, EC50 = 12.3 +/- 3.8 microM (n = 3). 5. The bradykinin-induced responses were competitively antagonized by the B2-receptor selective BK antagonists, Hoe-140 (D-Arg-[Hyp3, Thi5, D-Tic7, Oic8]BK; Icatibant; molar antagonist potency = 2.9 nM; pA2 = 8.54 +/- 0.06, n = 4; and slope = 1.04 +/- 0.08) and D-Arg0[Hyp3,Thi5,8, DPhe7]-BK (KB = 371 nM; pKB = 6.43 +/- 0.08, n = 4) in CEPI-17-CL4 cells. The antagonist potency of Hoe-140 against BK in normal, P-CEPI cells was 8.4 +/- 1.8 nM (pKi = 8.11 +/- 0.12, n = 4), this being similar to the potency observed in the immortalized cells. 6. This rank order of potency of agonist BK-related peptides, coupled with the antagonism of the BK-induced [3H]-IPs by the specific B2-receptor antagonists, strongly suggests that a B2-receptor subtype is involved in mediating functional phosphoinositide (PI) responses in the CEPI-17-CL4 and P-CEPI cells. 7. In conclusion, these data indicate that the P-CEPI and CEPI-17-CL4 cells express BK receptors of the B2-subtype coupled to the PI turnover signal transduction pathway. The CEPI-17-CL4 cells represent a good in vitro model of the human corneal epithelium in which to study further the role of BK receptors in its physiology and pathology, such as in allergic/inflammatory conditions, potential wound healing and other functions of the cornea.

Authors+Show Affiliations

Molecular Pharmacology Unit, Alcon Laboratories, Inc., Fort Worth, Texas 76134, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

9208130

Citation

Wiernas, T K., et al. "The Expression of Functionally-coupled B2-bradykinin Receptors in Human Corneal Epithelial Cells and Their Pharmacological Characterization With Agonists and Antagonists." British Journal of Pharmacology, vol. 121, no. 4, 1997, pp. 649-56.
Wiernas TK, Griffin BW, Sharif NA. The expression of functionally-coupled B2-bradykinin receptors in human corneal epithelial cells and their pharmacological characterization with agonists and antagonists. Br J Pharmacol. 1997;121(4):649-56.
Wiernas, T. K., Griffin, B. W., & Sharif, N. A. (1997). The expression of functionally-coupled B2-bradykinin receptors in human corneal epithelial cells and their pharmacological characterization with agonists and antagonists. British Journal of Pharmacology, 121(4), 649-56.
Wiernas TK, Griffin BW, Sharif NA. The Expression of Functionally-coupled B2-bradykinin Receptors in Human Corneal Epithelial Cells and Their Pharmacological Characterization With Agonists and Antagonists. Br J Pharmacol. 1997;121(4):649-56. PubMed PMID: 9208130.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The expression of functionally-coupled B2-bradykinin receptors in human corneal epithelial cells and their pharmacological characterization with agonists and antagonists. AU - Wiernas,T K, AU - Griffin,B W, AU - Sharif,N A, PY - 1997/6/1/pubmed PY - 1997/6/1/medline PY - 1997/6/1/entrez SP - 649 EP - 56 JF - British journal of pharmacology JO - Br J Pharmacol VL - 121 IS - 4 N2 - 1. Bradykinin (BK) and Lys-BK are peptides which are released at high nanomolar concentrations into the tear-film of ocular allergic patients. We hypothesized that these peptides may activate specific receptors on the ocular surface, especially the corneal epithelium (CE) and thus the CE cells may represent a potential target tissue for these kinins. 2. The purpose of the present studies, therefore, was to determine the presence of and the pharmacological characteristics of bradykinin receptors on normal cultured primary and SV40 virus-transformed human corneal epithelial (CEPI) cells by use of the accumulation of [3H]-inositol phosphates ([3H]-IPs) as a bioassay. 3. Bradykinin (BK) induced a maximal 1.95 +/- 0.24 fold (n = 17) and 2.51 +/- 0.29 fold (n = 26) stimulation of [3H]-IPs accumulation in normal, primary (P-CEPI) and SV40-immortalized (CEPI-17-CL4) cells, respectively. This contrasted with a maximal 3.2-4.5 fold and 2.0-2.9 fold stimulation by histamine (100 microM) and platelet activating factor (100 nM) in both cell-types, respectively. 4. The molar potencies of BK and some of its analogues in the CEPI-17-CL4 cells were as follows: BK (EC50 = 3.26 +/- 0.61 nM, n = 18), Lys-BK (EC50 = 0.95 +/- 0.16 nM, n = 5), Met-Lys-BK (EC50 = 2.3 +/- 0.42 nM, n = 5), Ile-Ser-BK (EC50 = 5.19 +/- 1.23 nM, n = 6), Ala3-Lys-BK (EC50 = 12.7 +/- 2.08 nM, n = 3), Tyr8-BK (EC50 = 19.3 +/- 0.77 nM, n = 3), Tyr5-BK (EC50 = 467 +/- 53 nM, n = 4) and des-Arg9-BK (EC50 = 14.1 +/- 2.7 microM, n = 4). The potencies of BK-related peptides in normal, P-CEPI cells were similar to those found in transformed cells, thus: BK, EC50 = 2.02 +/- 0.69 nM (n = 7), Tyr8-BK, EC50 = 14.6 +/- 2.7 nM (n = 3), Tyr5 = BK, EC50 = 310 +/- 70 nM (n = 4) and des-Arg9-BK, EC50 = 12.3 +/- 3.8 microM (n = 3). 5. The bradykinin-induced responses were competitively antagonized by the B2-receptor selective BK antagonists, Hoe-140 (D-Arg-[Hyp3, Thi5, D-Tic7, Oic8]BK; Icatibant; molar antagonist potency = 2.9 nM; pA2 = 8.54 +/- 0.06, n = 4; and slope = 1.04 +/- 0.08) and D-Arg0[Hyp3,Thi5,8, DPhe7]-BK (KB = 371 nM; pKB = 6.43 +/- 0.08, n = 4) in CEPI-17-CL4 cells. The antagonist potency of Hoe-140 against BK in normal, P-CEPI cells was 8.4 +/- 1.8 nM (pKi = 8.11 +/- 0.12, n = 4), this being similar to the potency observed in the immortalized cells. 6. This rank order of potency of agonist BK-related peptides, coupled with the antagonism of the BK-induced [3H]-IPs by the specific B2-receptor antagonists, strongly suggests that a B2-receptor subtype is involved in mediating functional phosphoinositide (PI) responses in the CEPI-17-CL4 and P-CEPI cells. 7. In conclusion, these data indicate that the P-CEPI and CEPI-17-CL4 cells express BK receptors of the B2-subtype coupled to the PI turnover signal transduction pathway. The CEPI-17-CL4 cells represent a good in vitro model of the human corneal epithelium in which to study further the role of BK receptors in its physiology and pathology, such as in allergic/inflammatory conditions, potential wound healing and other functions of the cornea. SN - 0007-1188 UR - https://www.unboundmedicine.com/medline/citation/9208130/The_expression_of_functionally_coupled_B2_bradykinin_receptors_in_human_corneal_epithelial_cells_and_their_pharmacological_characterization_with_agonists_and_antagonists_ DB - PRIME DP - Unbound Medicine ER -