The History and Mystery of Alveolar Epithelial Type II Cells: Focus on Their Physiologic and Pathologic Role in Lung

International Journal of Molecular Sciences

Barbara Wade¹  Elisa Baratella²  Luca Braga³  MariaConcetta Volpe⁴  Serena Maiocchi⁴  Francesco Salton⁵  Barbara Ruaro⁵  Paola Confalonieri⁵  Marco Confalonieri⁵ 

[1] City of Health and Science of Turin, Department of Science of Public Health and Pediatrics, University of Torino, 34128 Trieste, Italy;Department of Radiology, Department of Medicine, Surgery and Health Science, University of Trieste, 34128 Trieste, Italy;ICGEB, Area Science Park, Padriciano, 34128 Trieste, Italy;Life Sciences Department, University of Trieste, 34128 Trieste, Italy;Pulmonology Department, University Hospital of Cattinara, 34128 Trieste, Italy;

关键词: epithelial cells;    alveolar type II cells;    idiopathic pulmonary fibrosis;    chronic obstructive pulmonary disease (COPD);    lung cancer;    acute respiratory distress syndrome (ARDS);   

DOI  :  10.3390/ijms22052566

来源: DOAJ

【 摘 要 】

Alveolar type II (ATII) cells are a key structure of the distal lung epithelium, where they exert their innate immune response and serve as progenitors of alveolar type I (ATI) cells, contributing to alveolar epithelial repair and regeneration. In the healthy lung, ATII cells coordinate the host defense mechanisms, not only generating a restrictive alveolar epithelial barrier, but also orchestrating host defense mechanisms and secreting surfactant proteins, which are important in lung protection against pathogen exposure. Moreover, surfactant proteins help to maintain homeostasis in the distal lung and reduce surface tension at the pulmonary air–liquid interface, thereby preventing atelectasis and reducing the work of breathing. ATII cells may also contribute to the fibroproliferative reaction by secreting growth factors and proinflammatory molecules after damage. Indeed, various acute and chronic diseases are associated with intensive inflammation. These include oedema, acute respiratory distress syndrome, fibrosis and numerous interstitial lung diseases, and are characterized by hyperplastic ATII cells which are considered an essential part of the epithelialization process and, consequently, wound healing. The aim of this review is that of revising the physiologic and pathologic role ATII cells play in pulmonary diseases, as, despite what has been learnt in the last few decades of research, the origin, phenotypic regulation and crosstalk of these cells still remain, in part, a mystery.

【 授权许可】

Unknown