ADAMTS7 Attenuates House Dust Mite-Induced Airway Inflammation and Th2 Immune Responses

Abstract

Purpose: ADAMTS7 is a secreted metalloproteinase enzyme and proteoglycan associated with the early progression of coronary artery disease. However, there is limited information regarding the role of ADAMTS7 in lung adaptive immunity and inflammation. Thus, we sought to assess whether ADAMTS7 expression in the lung modulates house dust mite (HDM)-induced airway inflammation and Th2 immune response.

Methods: The role of ADAMTS7 in HDM-induced airway disease was assessed in ADAMTS7-deficient (ADAMTS7^-/-) mice and compared with the wild-type control mice by flow cytometry, ELISA, and histopathology. Furthermore, the antigen priming capability of dendritic cells (DC) was determined ex vivo by employing coculture with CD4⁺ OT-II cells.

Results: ADAMTS7^-/- mice develop an augmented eosinophilic airway inflammation, mucous cell metaplasia, and increased Th2 immune response to inhaled HDM. In addition, allergen uptake by lung DC and migration to draining mediastinal lymph node were significantly increased in ADAMTS7^-/- mice, which shows an enhanced capacity to mount allergen-specific T-cell proliferation and effector Th2 cytokine productions. We propose that the mechanism by which ADAMTS7 negatively regulates DC function involves attenuated antigen uptake and presentation capabilities, which reduces allergic sensitization and Th2 immune responses in the lung.

Conclusion: In aggregate, we provide compelling evidence that ADAMTS7 plays a pivotal role in allergic airway disease and Th2 immunity and would be an attractive target for asthma.

Keywords: ADAMTS7; Allergic airway inflammation (AAI); Lung dendritic cells; Type 2 immune response.

Fig. 1

ADAMTS7-deficient mice develop augmented HDM-induced airway inflammation. a Representative PCR analysis of genomic DNA isolated from WT and ADAMTS7^−/− lungs and DC. The absence of PCR product indicates ADAMTS7 deletion in ADAMTS7^−/− mice. b Diagram shows the HDM administration (i.p., intraperitoneal; i.n. intranasal) and analysis schedule. c Dot plots of BAL and lung cells (from a representative individual of indicated groups of mice and d quantitation of flow cytometry analysis showing the number of total cells (CD45 +), eosinophils (CD11b⁺ Siglec F⁺), and neutrophils (CD11b⁺ Ly-6G⁺) in BAL (top) and lung (bottom). e BAL levels of C–C chemokine CCL24 from WT and ADAMTS7^−/− mice. Results show the mean ± S.E. and represent two or more independent experiments (n = 8–10 mice, unpaired t-test, *P < 0.01)

Fig. 2

ADAMTS7^−/− develops increased Th2 immune response to inhaled HDM. Frequency of CD4+IL13+and CD4+IL17+T-cells in a BAL and b lung; and c cytokine secretion by ex vivo cultures of DLn cells that had been re-stimulated with HDM (100 µg/ml). Results show the mean ± S.E. and represent two or more independent experiments (n = 8–10 mice, unpaired t-test, *P < 0.01). d Images show histopathological sections of HDM-challenged lung from WT or ADAMTS7^−/− stained with H& E and PAS. Scale bars, 100 μm for × 100 and 50 μm for × 400 images. e Frequency of PAS+airways from HDM-challenged WT or ADAMTS7^−/−mice. Results show the mean ± S.E. and represent two or more independent experiments (n = 6 mice, unpaired t-test, *P < 0.01)

Fig. 3

Antigen uptake by DC and transport to the lung DLn is regulated by ADAMTS7. a Shown are the representative FACS dot plots of HDM-challenged WT and ADAMTS7^−/− in the lung and DLn, and b the frequencies of OVA-AF647+CD11c+DCs (gated on SiglecF⁻ CD11c⁺ MHCII^hi population) from WT and ADAMTS7^−/− mice 72 h after the allergen administration. Results represent the mean ± S.E, pooled from two independent experiments (n = 3–4 mice per group, *P < 0.05 unpaired t-test)

Fig. 4

ADAMTS7 is a negative regulator of antigen priming and presentation function. a OVA-specific proliferation in OT-II cells are presented as a percentage divided. b Representative pseudocolor plots, c bar graphs of CD4⁺ GATA3⁺ OT-II cells, and Th2 cytokines d IL4 and e IL13 in BMDC-OTII coculture supernatant from WT and ADAMTS7^−/− with and without OVA_323-339 peptide. (n = 6 per group and represent one of the three repeats). Data represent the mean ± SE, *P < 0.01, unpaired t-test