scholarly journals Surfactant Protein-A Function: Knowledge Gained From SP-A Knockout Mice

2022 ◽  
Vol 9 ◽  
Author(s):  
Lynnlee Depicolzuane ◽  
David S. Phelps ◽  
Joanna Floros

Pulmonary surfactant proteins have many roles in surfactant- related functions and innate immunity. One of these proteins is the surfactant protein A (SP-A) that plays a role in both surfactant-related processes and host defense and is the focus in this review. SP-A interacts with the sentinel host defense cell in the alveolus, the alveolar macrophage (AM), to modulate its function and expression profile under various conditions, as well as other alveolar epithelial cells such as the Type II cell. Via these interactions, SP-A has an impact on the alveolar microenvironment. SP-A is also important for surfactant structure and function. Much of what is understood of the function of SP-A and its various roles in lung health has been learned from SP-A knockout (KO) mouse experiments, as reviewed here. A vast majority of this work has been done with infection models that are bacterial, viral, and fungal in nature. Other models have also been used, including those of bleomycin-induced lung injury and ozone-induced oxidative stress either alone or in combination with an infectious agent, bone marrow transplantation, and other. In addition, models investigating the effects of SP-A on surfactant components or surfactant structure have contributed important information. SP-A also appears to play a role in pathways involved in sex differences in response to infection and/or oxidative stress, as well as at baseline conditions. To date, this is the first review to provide a comprehensive report of the functions of SP-A as learned through KO mice.

2020 ◽  
Vol 319 (2) ◽  
pp. C316-C320
Author(s):  
Skylar D. King ◽  
Shi-You Chen

Pulmonary surfactant is a heterogeneous active surface complex made up of lipids and proteins. The major glycoprotein in surfactant is surfactant protein A (SP-A), which is released into the alveolar lumen from cytoplasmic lamellar bodies in type II alveolar epithelial cells. SP-A is involved in phospholipid absorption. SP-A together with other surfactant proteins and phospholipids prevent alveolar collapse during respiration by decreasing the surface tension of the air-liquid interface. Additionally, SP-A interacts with pathogens to prevent their propagation and regulate host immune responses. Studies in human and animal models have shown that deficiencies or mutations in surfactant components result in various lung or kidney pathologies, suggesting a role for SP-A in the development of lung and kidney diseases. In this mini-review, we discuss the current understanding of SP-A functions, recent findings of its dysfunction in specific lung and kidney pathologies, and how SP-A has been used as a biomarker to detect the outcome of lung diseases.


PLoS ONE ◽  
2007 ◽  
Vol 2 (12) ◽  
pp. e1370 ◽  
Author(s):  
Steven S. Giles ◽  
Aimee K. Zaas ◽  
Mike F. Reidy ◽  
John R. Perfect ◽  
Jo Rae Wright

1994 ◽  
Vol 269 (8) ◽  
pp. 5833-5841
Author(s):  
F.X. McCormack ◽  
H.M. Calvert ◽  
P.A. Watson ◽  
D.L. Smith ◽  
R.J. Mason ◽  
...  

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Tara Bocking ◽  
Laura Johnson ◽  
Amitoj Singh ◽  
Atul Desai ◽  
Gurpreet Kaur Aulakh ◽  
...  

Abstract Background Respiratory diseases are a major cause of morbidity and mortality in the horses of all ages including foals. There is limited understanding of the expression of immune molecules such as tetraspanins and surfactant proteins (SP) and the regulation of the immune responses in the lungs of the foals. Therefore, the expression of CD9, SP-A and SP-D in foal lungs was examined. Results Lungs from one day old (n = 6) and 30 days old (n = 5) foals were examined for the expression of CD9, SP-A, and SP-D with immunohistology and Western blots. Western blot data showed significant increase in the amount of CD9 protein (p = 0.0397) but not of SP-A and SP-D at 30 days of age compared to one day. Immunohistology detected CD9 in the alveolar septa and vascular endothelium but not the bronchiolar epithelium in the lungs of the foals in both age groups. SP-A and SP-D expression was localized throughout the alveolar septa including type II alveolar epithelial cells and the vascular endothelium of the lungs in all the foals. Compared to one day old foals, the expression of SP-A and SP-D appeared to be increased in the bronchiolar epithelium of 30 day old foals. Pulmonary intravascular macrophages were also positive for SP-A and SP-D in 30 days old foals and these cells are not developed in the day old foals. Conclusions This is the first data on the expression of CD9, SP-A and SP-D in the lungs of foals.


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