Surfactant proteins and cell markers in the respiratory epithelium of the amphibian, Ambystoma mexicanum.
The respiratory tract is lined by diverse epithelial cell types whose morphology, gene expression and functions are highly specialized along the cephalo-caudal axis of the lung. Pulmonary gas exchange, surface tension reduction, host defense, fluid and electrolyte transport are functions shared by various vertebrate species, each organism facing similar requirements for adaptation to air breathing. Consistent with this concept, we have identified distinct respiratory epithelial cell populations in the amphibian, Ambystoma mexicanum, using morphologic, histochemical and immunochemical techniques. Thyroid transcription factor-1 (TTF-1), a homeodomain nuclear transcription factor critical to lung formation, and surfactant protein B (SP-B), an amphipathic polypeptide required for surfactant function, were detected in the peripheral respiratory epithelial cells of the axolotl lung, in cells with characteristics of Type II alveolar epithelial cells in mammals. beta-Tubulin and carbohydrate staining identified distinct subsets of ciliated and goblet cells. SP-D, a member of the collectin family of innate host defense proteins, was also detected in peripheral epithelial cells of the axolotl lung. Pulmonary surfactant and host defense proteins are shared across diverse phyla supporting the concept that pulmonary structure and function have evolved from common ancestors.
Miller
L D
LD
Children's Hospital Medical Center, Division of Pulmonary Biology, Cincinnati, OH 45229-3039, USA.
Wert
S E
SE
Whitsett
J A
JA
D000558:Ambystoma mexicanum; D000818:Animals; D004847:Epithelial Cells / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism; D008168:Lung / Q000033:anatomy & histology / Q000166:cytology / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism; D011510:Proteolipids / Q000378:metabolism; D037663:Pulmonary Surfactant-Associated Protein D; D011663:Pulmonary Surfactants / Q000378:metabolism; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000378:metabolism; D014404:Tubulin / Q000378:metabolism
D006023:Glycoproteins; D009687:Nuclear Proteins; D011510:Proteolipids; D037663:Pulmonary Surfactant-Associated Protein D; D011663:Pulmonary Surfactants; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors; D014404:Tubulin