Expression and coupling of neurokinin receptor subtypes to inositol phosphate and calcium signaling pathways in human airway smooth muscle cells

Abstract

Emala CW Sr. Expression and coupling of neurokinin receptor subtypes to inositol phosphate and calcium signaling pathways in human airway smooth muscle cells. Am J Physiol Lung Cell Mol Physiol 294: L523-L534, 2008. First published January 18, 2008 doi:10.1152/ajplung.00328.2007.-Neuropeptide tachykinins (substance P, neurokinin A, and neurokinin B) are present in peripheral terminals of sensory nerve fibers within the respiratory tract and cause airway contractile responses and hyperresponsiveness in humans and most mammalian species. Three subtypes of neurokinin receptors (NK 1R, NK2R, and NK3R) classically couple to G q protein-mediated inositol 1,4,5-trisphosphate (IP3) synthesis and liberation of intracellular Ca 2ϩ , which initiates contraction, but their expression and calcium signaling mechanisms are incompletely understood in airway smooth muscle. All three subtypes were identified in native and cultured human airway smooth muscle (HASM) and were subsequently overexpressed in HASM cells using a human immunodeficiency virus-1-based lentivirus transduction system. Specific NKR agonists {NK 1R, [Sar 9 ,Met(O2) 11 ]-substance P; NK 2 R, [␤-Ala 8 ]-neurokinin A(4 -10); NK 3 R, senktide} stimulated inositol phosphate synthesis and increased intracellular Ca 2ϩ concentration ([Ca 2ϩ ]i) in native HASM cells and in HASM cells transfected with each NKR subtype. These effects were blocked by NKR-selective antagonists (NK 1R, L-732138; NK2R, GR-159897; NK 3R, SB-222200). The initial transient and sustained phases of increased [Ca 2ϩ ]i were predominantly inhibited by the IP3 receptor antagonist 2-aminoethoxydiphenyl borate (2-APB) or the store-operated Ca 2ϩ channel antagonist SKF-96365, respectively. These results show that all three subtypes of NKRs are expressed in native HASM cells and that IP 3 levels are the primary mediators of NKR-stimulated initial [Ca 2ϩ ] i increases, whereas store-operated Ca 2ϩ channels mediate the sustained phase of the [Ca 2ϩ ]i increase. intracellular calcium; ryanodine; actin; myosin; lentivirus TACHYKININS ARE STORED AND RELEASED from unmyelinated pulmonary C fibers in airways (8,30,31,44) and evoke inflammatory peripheral effects including vasodilation, plasma extravasation, leukocyte adhesion, facilitation of cholinergic neurotransmission, and epithelial cell secretion in the airways (1, 12, 16), which are referred to as neurogenic inflammation. Local release of tachykinins from peripheral sensory nerves may also lead to airway contractile responses and hyperresponsiveness in human and most mammalian species (32, 42). At least three subtypes of neurokinin receptors (NK 1 R, NK 2 R, and NK 3 R) have been characterized, which exhibit preferential affinity for the endogenous neuropeptides substance P, neurokinin A, and neurokinin B, respectively (33). All three receptor subtypes are members of the seven-transmembrane domain receptor superfamily that couple to G q proteins (50).Classically, the expression of NK 1 R and NK 2 R has been described in both the nervous system and p...

Neurokinin 1 Receptor Mediates Membrane Blebbing in HEK293 Cells through a Rho/Rho-associated Coiled-coil Kinase-dependent Mechanism

“…Activation of NK1R couples to G q proteins (14,53), as well as G s (15) and G i and G z (16,54). G q is an important mediator of NK1R activation and leads to activation of PLC that causes phosphatidylinositol 4,5-bisphosphate cleavage to diacylglycerol and IP 3 (53).…”

“…G q is an important mediator of NK1R activation and leads to activation of PLC that causes phosphatidylinositol 4,5-bisphosphate cleavage to diacylglycerol and IP 3 (53). The release of IP 3 ultimately leads to release of internal stores of calcium.…”

Active Components of Ginger Potentiate β-Agonist–Induced Relaxation of Airway Smooth Muscle by Modulating Cytoskeletal Regulatory Proteins

“…Cells were stably transfected as previously described (25), with modifications detailed in the online supplement.…”

Novel Pituitary Actions of TAC3 Gene Products in Fish Model: Receptor Specificity and Signal Transduction for Prolactin and Somatolactin α Regulation by Neurokinin B (NKB) and NKB-Related Peptide in Carp Pituitary Cells

“…Multiple genes for tachykinins, eg, TAC1 coding for SP and NKA, TAC3 coding for NKB, and TAC4 coding for HK-1/endokinins, have been identified (3) and believed to be the result of gene duplication occurred during vertebrate evolution (4). The biological actions of tachykinins are mediated by 3 major types of neurokinin receptors (NKRs), namely NK1R, NK2R, and NK3R (3), which are class I G protein-coupled receptors functionally coupled with phospholipase C (PLC)/inositol 1,4,5-triphosphate (IP 3 )/protein kinase C (PKC), MAPK, cAMP/protein kinase A (PKA), and Ca 2ϩ -dependent cascades (5)(6)(7)(8)(9)(10). Individual NKR subtypes are known to exhibit differential binding for different tachykinins, with NK1R preferring SP, NK2R preferring NKA, and NK3R preferring NKB, respectively (3).…”