Differential expression of chitinases identify subsets of murine airway epithelial cells in allergic inflammation.
The mammalian chitinase family includes members both with and without enzymatic activity against chitin, a product of fungal cell walls, exoskeletons of crustaceans and insects, and the microfilarial sheaths of parasitic nematodes. Two members of that family, Ym1 and acidic mammalian chitinase (AMCase), are strongly upregulated in pulmonary T helper (Th) 2 inflammation but not in Th1 inflammation. The sites of expression of these products are incompletely known. We show here that, in two different models of Th2 inflammation, Ym1 and AMCase are mutually exclusively expressed in proximal vs. distal airway epithelium, respectively, whereas both are expressed in alveolar macrophages. This regional difference along the airway corresponds to the previously noted distinction between mucus positive proximal cells and mucus negative distal cells under the same conditions. Among distal cells, AMCase colocalizes with epithelial cells expressing the Clara cell marker Clara cell secretory protein. These AMCase-expressing cells retain expression of FOXA2, a transcription factor whose downregulation in association with IL-13 signaling has previously been associated with production of mucus in proximal airway epithelial cells. These results provide evidence that secretory cells of proximal and distal airways undergo fundamentally different gene expression programs in response to allergic inflammation. Furthermore, AMCase provides the first positive molecular marker of distal Clara cell secretory protein-expressing cells under these conditions.
Department of Pathology, Yale University School of Medicine and Pathology and Laboratory Medicine Service, Veterans Affairs Connecticut HealthCare System, West Haven, 06520-8023, USA. Robert.Homer@yale.edu
Robert J
RJ
Homer
Zhou
Z
Zhu
Lauren
L
Cohn
Chun Gun
CG
Lee
Wendy I
WI
White
Suping
S
Chen
Jack A
JA
Elias
D000818:Animals; D015415:Biomarkers / Q000032:analysis; D002688:Chitinases / Q000378:metabolism*; D051542:Hepatocyte Nuclear Factor 3-beta / Q000378:metabolism; D006967:Hypersensitivity / Q000201:enzymology / Q000276:immunology; D007249:Inflammation / Q000201:enzymology; D018793:Interleukin-13 / Q000235:genetics / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010047:Ovalbumin / Q000494:pharmacology; D020545:Respiratory Mucosa / Q000166:cytology / Q000201:enzymology* / Q000276:immunology*; D014598:Uteroglobin / Q000378:metabolism
D015415:Biomarkers; C496503:Foxa2 protein, mouse; D018793:Interleukin-13; C556390:Scgb1a1 protein, mouse; D051542:Hepatocyte Nuclear Factor 3-beta; D010047:Ovalbumin; D014598:Uteroglobin; D002688:Chitinases