The phosphatase CD148 promotes airway hyperresponsiveness through SRC family kinases
Tamiko R. Katsumoto, … , Dean Sheppard, Arthur Weiss
Tamiko R. Katsumoto, … , Dean Sheppard, Arthur Weiss
Published April 1, 2013
Citation Information: J Clin Invest. 2013;123(5):2037-2048. https://doi.org/10.1172/JCI66397.
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Research Article Pulmonology

The phosphatase CD148 promotes airway hyperresponsiveness through SRC family kinases

Abstract

Increased airway smooth muscle (ASM) contractility and the development of airway hyperresponsiveness (AHR) are cardinal features of asthma, but the signaling pathways that promote these changes are poorly understood. Tyrosine phosphorylation is tightly regulated by the opposing actions of protein tyrosine kinases and phosphatases, but little is known about whether tyrosine phosphatases influence AHR. Here, we demonstrate that genetic inactivation of receptor-like protein tyrosine phosphatase J (Ptprj), which encodes CD148, protected mice from the development of increased AHR in two different asthma models. Surprisingly, CD148 deficiency minimally affected the inflammatory response to allergen, but significantly altered baseline pulmonary resistance. Mice specifically lacking CD148 in smooth muscle had decreased AHR, and the frequency of calcium oscillations in CD148-deficient ASM was substantially attenuated, suggesting that signaling pathway alterations may underlie ASM contractility. Biochemical analysis of CD148-deficient ASM revealed hyperphosphorylation of the C-terminal inhibitory tyrosine of SRC family kinases (SFKs), implicating CD148 as a critical positive regulator of SFK signaling in ASM. The effect of CD148 deficiency on ASM contractility could be mimicked by treatment of both mouse trachea and human bronchi with specific SFK inhibitors. Our studies identify CD148 and the SFKs it regulates in ASM as potential targets for the treatment of AHR.

Authors

Tamiko R. Katsumoto, Makoto Kudo, Chun Chen, Aparna Sundaram, Elliott C. Callahan, Jing W. Zhu, Joseph Lin, Connor E. Rosen, Boryana N. Manz, Jae W. Lee, Michael A. Matthay, Xiaozhu Huang, Dean Sheppard, Arthur Weiss

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Figure 7

CD148-deficient tracheas show diminished contractility, decreased calcium oscillation frequency, and dysregulated SFK signaling in ASM.

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CD148-deficient tracheas show diminished contractility, decreased calciu...
Mouse tracheal rings were isolated and stimulated with MCh (A), and contractile force measurements were made with a force transducer. Data are the mean ± SEM with at least 6 tracheal rings per group. *P < 0.05, ***P < 0.001, 2-way ANOVA. (B) Tracheal smooth muscle samples directly isolated from mice were lysed, ultracentrifuged, separated by SDS-PAGE, and transferred to a membrane. Membranes were probed with antibodies against phosphorylated SRC Y527 (inhibitory tyrosine) and total SRC as a loading control. Data shown in this figure are representative of 4 independent experiments. (C) Densitometry quantification of Western blots showing relative intensity of pSRC Y527 compared with total SRC. **P < 0.01, unpaired 2-tailed Student’s t test. (D) Representative calcium oscillations induced by 50 μM MCh in lung slices from BALB/c WT control (upper panel) and PtprjTM–/TM– (lower panel) mice. Final fluorescence values are expressed as ratios (F/F0), normalized to the fluorescence immediately prior to the addition of an agonist (F0). (E) Average frequency of calcium oscillations, comparing WT control with PtprjTM–/TM– mice. Data include 6 animals per group. Data show the mean ± SD. ***P < 0.001, unpaired 2-tailed Student’s t test.