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Induction of asthma causes sensitization of the carotid bodies to lysophosphatidic acid
Author(s) -
Jendzjowsky Nicholas Gregory,
Roy Arijit,
Wilson Richard
Publication year - 2019
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.2019.33.1_supplement.lb580
Subject(s) - lysophosphatidic acid , ovalbumin , bronchoconstriction , asthma , medicine , sensitization , endocrinology , methacholine , trpv1 , reflex , chemistry , receptor , immunology , lung , transient receptor potential channel , immune system , respiratory disease
Previously, we demonstrated an important role for the carotid bodies in asthmatic bronchoconstriction. Specifically, we showed that an allergen‐induced increase in circulating lysophosphatidic acid (LPA) in asthmatic rats activates LPA receptors (LPAr) in the carotid bodies and post‐ganglionic TRPV1 channels, provoking vagal activity and thereby triggering acute bronchoconstriction (Jendzjowsky et al. 2018 Nat Comm. 9, 4030). Here we report that induction of asthma causes molecular and functional changes to the carotid bodies that sensitize them to LPA. Experiments were carried out using the standard ovalbumin‐sensitized brown Norway rat model of asthma. Carotid bodies and petrosal ganglia were extracted 3 hours after the third ovalbumin challenge in asthmatic (OVA) or third saline challenge in naïve (N) rats. Using qPCR (Δctt OVA vs N), LPAr expression was increased in the carotid body (LPAr1: 556x; LPAr2: 20x; LPAr3: 2x; LPAr4: 150x; LPAr5 only detected in OVA: LPAr6: 175x; TRPV1 not detected, as demonstrated previously Roy et al. 2012 J Appl Physiol 112:212–224) whereas LPAr 1–6 and TRPV1 were similarly expressed in petrosal ganglia of OVA and N rats. Using the perfused ex vivo carotid body preparation, baseline normalized carotid sinus nerve responses to increasing doses of LPA activity, were significantly augmented in OVA compared to N rats (2.5uM‐ OVA: 1.12 ± 0.01 N: 1.05 ± 0.02, p=0.162; 5uM: OVA: 1.23 ± 0.03 N:1.10 ± 0.02, p=0.009; 10uM: OVA: 1.40 ± 0.07 N: 1.17 ± 0.03, p<0.001). In contrast, carotid body activity in response to hypoxia was not different between OVA (2.54 ± 0.47) and N (1.95 ± 0.10) rats (p=0.243). Our data suggest that asthmatic carotid bodies have enhanced responsiveness to LPA, independent of hypoxic sensitivity. These changes likely contribute to the acute allergen‐induced bronchoconstriction which is the hallmark of asthma that appears to be mediated, in part, by a novel carotid body‐vagal‐lung neuronal pathway. Targeting carotid body LPA signalling may reduce asthmatic bronchoconstriction and provide new pharmaceutical targets for inflammatory lung disease. Support or Funding Information This project was funded by The Lung Association and Canadian Institute for Health Research. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .