Selectivity of recombinant human leukotriene D4, leukotriene B4, and lipoxin A4 receptors with aspirin-triggered 15-epi-LXA4 and regulation of vascular and …

K Gronert, T Martinsson-Niskanen, S Ravasi… - The American journal of …, 2001 - Elsevier
K Gronert, T Martinsson-Niskanen, S Ravasi, N Chiang, CN Serhan
The American journal of pathology, 2001Elsevier
Aspirin-triggered lipoxin A4 (ATL, 15-epi-LXA4) and leukotriene D4 (LTD4) possess
opposing vascular actions mediated via receptors distinct from the LXA4 receptor (ALX) that
is involved in leukocyte trafficking. Here, we identified these receptors by nucleotide
sequencing and demonstrate that LTD4 receptor (CysLT1) is induced in human vascular
endothelia by interleukin-1β. Recombinant CysLT1receptor gave stereospecific binding with
both [3H]-LTD4 and a novel labeled mimetic of ATL ([3H]-ATLa) that was displaced with …
Aspirin-triggered lipoxin A4 (ATL, 15-epi-LXA4) and leukotriene D4(LTD4) possess opposing vascular actions mediated via receptors distinct from the LXA4 receptor (ALX) that is involved in leukocyte trafficking. Here, we identified these receptors by nucleotide sequencing and demonstrate that LTD4 receptor (CysLT1) is induced in human vascular endothelia by interleukin-1β. Recombinant CysLT1receptor gave stereospecific binding with both [3H]-LTD4 and a novel labeled mimetic of ATL ([3H]-ATLa) that was displaced with LTD4 and ATLa (∼IC50 0.2 to 0.9 nmol/L), but not with a bioinactive ATL isomer. The clinically used CysLT1 receptor antagonist, Singulair, showed a lower rank order for competition with [3H]-ATLa (IC50 ≈ 8.3 nmol/L). In contrast, LTD4 was an ineffective competitive ligand for recombinant ALX receptor with [3H]-ATLa, and ATLa did not compete for [3H]-LTB4 binding with recombinant LTB4 receptor. Endogenous murine CysLT1receptors also gave specific [3H]-ATLa binding that was displaced with essentially equal affinity by LTD4 or ATLa. Systemic ATLa proved to be a potent inhibitor (>50%) of CysLT1-mediated vascular leakage in murine skin (200 μg/kg) in addition to its ability to block polymorphonuclear leukocyte recruitment to dorsal air pouch (4 μg/kg). These results indicate that ATL and LTD4 bind and compete with equal affinity at CysLT1, providing a molecular basis for aspirin-triggered LXs serving as a local damper of both vascular CysLT1 signals as well as ALX receptor-regulated polymorphonuclear leukocyte traffic.
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