Expression of functional NK1 receptors in human alveolar macrophages: superoxide anion production, cytokine release and involvement of NF-kappaB pathway.
1 Substance P (SP) is deeply involved in lung pathophysiology and plays a key role in the modulation of inflammatory-immune processes. We previously demonstrated that SP activates guinea-pig alveolar macrophages (AMs) and human monocytes, but a careful examination of its effects on human AMs is still scarce. 2 This study was undertaken to establish the role of SP in human AM isolated from healthy smokers and non-smokers, by evaluating the presence of tachykinin NK(1) receptors (NK-1R) and SP's ability to induce superoxide anion (O(2)(-)) production and cytokine release, as well as activation of the nuclear factor-kappaB (NF-kappaB) pathway. 3 By Western blot analysis and immunofluorescence, we demonstrate that authentic NK-1R are present on human AMs, a three-fold enhanced expression being observed in healthy smokers. These NK-1R are functional, as SP and NK(1) agonists dose-dependently induce O(2)(-) production and cytokine release. In AMs from healthy smokers, SP evokes an enhanced respiratory burst and a significantly increased release of tumor necrosis factor-alpha as compared to healthy non-smokers, but has inconsistent effects on IL-10 release. The NK(1) selective antagonist CP 96,345 ((2S,3S)-cis-2-diphenylmethyl-N[(2-methoxyphenyl)-methyl]-1-azabicyclo-octan-3-amine)) competitively antagonized SP-induced effects. 4 SP activates the transcription factor NF-kappaB, a three-fold increased nuclear translocation being observed in AMs from healthy smokers. This effect is receptor-mediated, as it is reproduced by the NK(1) selective agonist [Sar(9)Met(O(2))(11)]SP and reverted by CP 96,345. 5 These results clearly indicate that human AMs possess functional NK-1R on their surface, which are upregulated in healthy smokers, providing new insights on the mechanisms involved in tobacco smoke toxicity.
Bardelli
Claudio
C
Department of Medical Sciences, School of Medicine, University of Piemonte Orientale A. Avogadro, Via Solaroli, 17, 28100 Novara, Italy.
Gunella
Gabriele
G
Varsaldi
Federica
F
Balbo
Pietro
P
Del Boca
Elisa
E
Bernardone
Ilaria Seren
IS
Amoruso
Angela
A
Brunelleschi
Sandra
S
D000328:Adult; D000368:Aged; D016207:Cytokines / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D006801:Humans; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D016328:NF-kappa B / Q000378:metabolism*; D018040:Receptors, Neurokinin-1 / Q000819:agonists / Q000096:biosynthesis* / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D012907:Smoking / Q000235:genetics / Q000378:metabolism; D013373:Substance P / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism*
D016207:Cytokines; D016328:NF-kappa B; D018040:Receptors, Neurokinin-1; D013481:Superoxides; D013373:Substance P