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Involvement of CYP4A‐mediated MAPK pathway in vascular contraction in A 2A adenosine receptor knockout mice
Author(s) -
Ponnoth Dovenia S,
Nayeem Mohammed A,
Kunduri Swati S,
Fil Daniel,
Tilley Stephen,
Ledent Catherine,
Mustafa S Jamal
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.1021.6
Subject(s) - endocrinology , protein kinase c , medicine , contraction (grammar) , chemistry , agonist , adenosine , knockout mouse , mapk/erk pathway , ccpa , receptor , adenosine receptor , kinase , biochemistry
We have shown earlier that A 2A adenosine receptor (AR) knockout (A 2A KO) mice have increased vascular contraction ( Ponnoth et al, AJP 2009 ). We hypothesize that in A 2A KO mice, vascular contraction depends on ω‐hydroxylase (CYP4A), through up‐regulation of A 1 AR via a MAPK pathway. Organ bath and western blot experiments were done with isolated aortas from A 2A KO and wild type (WT) mice. A 2A KO mice had higher contraction to selective A 1 agonist, CCPA (49.2±8.5 vs 27±5.9% at 10 −6 M, p<0.01) and 20‐HETE (ω‐hydroxylation product; 21.1 ±3.3 vs. 50.6±8.8%). Contraction to NECA (non‐selective adenosine analog) in A 2A KO aorta was abolished with p42/p44 MAPK inhibitor PD‐98059 (10 −6 M). PKC blocker chelerythrine chloride lowered contraction in A 2A KO tissues to CCPA (52±8 vs 29±5.2 % at 10 −7 M, p<0.05). Western blot data indicated higher expressions of A 1 AR (68 vs. 49%), CYP4A (81 vs 62%), PKC‐ε (69 vs 58%), PKC‐α (59 vs 48%) and p‐ERK 1/2 (92 vs. 66%) in KO tissues than WT. CCPA (10 −6 M) further increased the expression of these proteins in KO aorta than WT. HET0016 (CYP4A inhibitor; 10 −5 M) decreased the CCPA‐induced increase in protein expression of A 1 AR (52%), CYP4A (77%), p‐ERK 1/2 (69%), PKC‐α (45%) and PKC‐ε (32%) in A 2A KO tissue. These data suggest that CYP4A mediates contraction in A 2A KO mice aorta through up‐regulation of A 1 AR, possibly through MAPK pathway via PKC isoforms. (HL027339, HL09444, HL071802)