Alveolar epithelial type II cell: defender of the alveolus revisited
- PMID: 11686863
- PMCID: PMC59567
- DOI: 10.1186/rr36
Alveolar epithelial type II cell: defender of the alveolus revisited
Abstract
In 1977, Mason and Williams developed the concept of the alveolar epithelial type II (AE2) cell as a defender of the alveolus. It is well known that AE2 cells synthesise, secrete, and recycle all components of the surfactant that regulates alveolar surface tension in mammalian lungs. AE2 cells influence extracellular surfactant transformation by regulating, for example, pH and [Ca2+] of the hypophase. AE2 cells play various roles in alveolar fluid balance, coagulation/fibrinolysis, and host defence. AE2 cells proliferate, differentiate into AE1 cells, and remove apoptotic AE2 cells by phagocytosis, thus contributing to epithelial repair. AE2 cells may act as immunoregulatory cells. AE2 cells interact with resident and mobile cells, either directly by membrane contact or indirectly via cytokines/growth factors and their receptors, thus representing an integrative unit within the alveolus. Although most data support the concept, the controversy about the character of hyperplastic AE2 cells, reported to synthesise profibrotic factors, proscribes drawing a definite conclusion today.
Figures
![Figure 1](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/59567/bin/rr36-1.gif)
![Figure 2](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/59567/bin/rr36-2.gif)
![Figure 3](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/59567/bin/rr36-3.gif)
![Figure 4](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/59567/bin/rr36-4.gif)
![Figure 5](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/59567/bin/rr36-5.gif)
![Figure 6](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/59567/bin/rr36-6.gif)
Similar articles
-
The Three-Dimensional Ultrastructure of the Human Alveolar Epithelium Revealed by Focused Ion Beam Electron Microscopy.Int J Mol Sci. 2020 Feb 6;21(3):1089. doi: 10.3390/ijms21031089. Int J Mol Sci. 2020. PMID: 32041332 Free PMC article.
-
Type II alveolar cell. Defender of the alveolus.Am Rev Respir Dis. 1977 Jun;115(6 Pt 2):81-91. doi: 10.1164/arrd.1977.115.S.81. Am Rev Respir Dis. 1977. PMID: 326115 No abstract available.
-
Pulmonary surfactant itself must be a strong defender against SARS-CoV-2.Med Hypotheses. 2020 Nov;144:110020. doi: 10.1016/j.mehy.2020.110020. Epub 2020 Jun 20. Med Hypotheses. 2020. PMID: 32590326 Free PMC article.
-
Pulmonary surfactant: no mere paint on the alveolar wall.Respirology. 1996 Dec;1(4):247-57. doi: 10.1111/j.1440-1843.1996.tb00040.x. Respirology. 1996. PMID: 9441113 Review.
-
Biology of alveolar type II cells.Respirology. 2006 Jan;11 Suppl:S12-5. doi: 10.1111/j.1440-1843.2006.00800.x. Respirology. 2006. PMID: 16423262 Review.
Cited by
-
Endogenous LXR signaling controls pulmonary surfactant homeostasis and prevents lung inflammation.Cell Mol Life Sci. 2024 Jul 6;81(1):287. doi: 10.1007/s00018-024-05310-3. Cell Mol Life Sci. 2024. PMID: 38970705 Free PMC article.
-
Pyrroloquinoline quinone ameliorates PM2.5-induced pulmonary fibrosis through targeting epithelial-mesenchymal transition.J Cell Mol Med. 2024 Apr;28(8):e18299. doi: 10.1111/jcmm.18299. J Cell Mol Med. 2024. PMID: 38613355 Free PMC article.
-
Pharmacological expansion of type 2 alveolar epithelial cells promotes regenerative lower airway repair.Proc Natl Acad Sci U S A. 2024 Apr 16;121(16):e2400077121. doi: 10.1073/pnas.2400077121. Epub 2024 Apr 10. Proc Natl Acad Sci U S A. 2024. PMID: 38598345
-
Development of an in vitro human alveolar epithelial air-liquid interface model using a small molecule inhibitor cocktail.BMC Mol Cell Biol. 2024 Mar 18;25(1):9. doi: 10.1186/s12860-024-00507-7. BMC Mol Cell Biol. 2024. PMID: 38500038 Free PMC article.
-
The Role of the Nuclear Factor-Kappa B (NF-κB) Pathway in SARS-CoV-2 Infection.Pathogens. 2024 Feb 12;13(2):164. doi: 10.3390/pathogens13020164. Pathogens. 2024. PMID: 38392902 Free PMC article. Review.
References
-
- Macklin CC. The pulmonary alveolar mucoid film and the pneumonocytes. Lancet. 1954;29:1099–1104. - PubMed
-
- Mason RJ, Williams MC. Type II alveolar cell: defender of the alveolus. Am Rev Respir Dis. 1977;115:81–91. - PubMed
-
- Von Neergaard K. New opinions about the fundamentals of respiratory mechanics. The retraction force of the lung in relationship to the surface tension within the alveoles [in German]. Z ges exp Med. 1929;66:373–394.
-
- Pattle R. Properties, function and origin of the alveolar lining layer. Nature. 1955;175:1125–1126. - PubMed
-
- Clements JA. Surface tension of lung extracts. Proc Soc Exp Biol Med. 1957;95:170–172. - PubMed
Publication types
MeSH terms
Substances
LinkOut - more resources
Full Text Sources
Other Literature Sources
Miscellaneous