scholarly journals Research article expression of surfactant protein-A and D, and CD9 in lungs of 1 and 30 day old foals

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Tara Bocking ◽  
Laura Johnson ◽  
Amitoj Singh ◽  
Atul Desai ◽  
Gurpreet Kaur Aulakh ◽  
...  
Keyword(s):  
Vascular Endothelium ◽  
Protein A ◽  
Age Groups ◽  
Surfactant Protein ◽  
Alveolar Epithelial Cells ◽  
Western Blots ◽  
Alveolar Epithelial ◽  
Research Article ◽  
Bronchiolar Epithelium ◽  
Alveolar Septa

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.

scholarly journals Recent progress on surfactant protein A: cellular function in lung and kidney disease development

2020 ◽  
Vol 319 (2) ◽  
pp. C316-C320
Author(s):  
Skylar D. King ◽  
Shi-You Chen
Keyword(s):  
Kidney Diseases ◽  
Protein A ◽  
Active Surface ◽  
Surfactant Protein ◽  
Alveolar Epithelial Cells ◽  
Surfactant Protein A ◽  
Alveolar Epithelial ◽  
Host Immune Responses ◽  
Alveolar Collapse ◽  
Lung And Kidney

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.

Distinct effects of oxygen on surfactant protein B expression in bronchiolar and alveolar epithelium

1992 ◽  
Vol 262 (1) ◽  
pp. L32-L39 ◽  
Author(s):  
K. A. Wikenheiser ◽  
S. E. Wert ◽  
J. R. Wispe ◽  
M. Stahlman ◽  
M. D'Amore-Bruno ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Alveolar Epithelium ◽  
Surfactant Protein ◽  
Alveolar Epithelial Cells ◽  
Cell Protein ◽  
Altered Expression ◽  
Alveolar Epithelial ◽  
Surfactant Protein B ◽  
Bronchiolar Epithelium ◽  
Protein B

Hyperoxia causes severe lung injury in association with altered expression of surfactant proteins and lipids. To test whether oxygen induces surfactant protein B (SP-B) expression in specific respiratory epithelial cells, adult B6C3F1 and FVB/N mice were exposed to room air or 95% oxygen for 1–5 days. Northern blot analysis demonstrated an 8- to 10-fold increase in SP-B mRNA after 3 days that was maintained thereafter. In situ hybridization localized SP-B mRNA to bronchial, bronchiolar, and alveolar epithelial cells. Hyperoxia was associated with increased SP-B mRNA, noted primarily in the bronchiolar epithelium and decreased SP-B mRNA in the alveolar epithelium. After 5 days, central regions of lung parenchyma were nearly devoid of SP-B mRNA, while SP-B mRNA was maintained in alveolar cell populations close to vascular structures. To determine whether increased bronchiolar expression of SP-B mRNA during hyperoxia was a specific response, the abundance of CC10 mRNA (a Clara cell protein) was assessed. CC10 mRNA was detected in tracheal, bronchial, and bronchiolar, but not alveolar epithelium and was decreased upon exposure to hyperoxia. Immunocytochemistry demonstrated that SP-B proprotein was detected in bronchial, bronchiolar, and alveolar epithelial cells with staining increased in the bronchial and bronchiolar epithelium upon exposure to hyperoxia. SP-B gene expression in the respiratory epithelium is regulated at a pretranslational level and occurs in a cell specific manner during hyperoxic injury in the mouse.

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
Keyword(s):  
Oxidative Stress ◽  
Host Defense ◽  
Protein A ◽  
Infectious Agent ◽  
Surfactant Protein ◽  
Alveolar Epithelial Cells ◽  
Surfactant Protein A ◽  
Alveolar Epithelial ◽  
Pulmonary Surfactant Proteins ◽  
And Function

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.

scholarly journals Abrogation of ER stress-induced apoptosis of alveolar epithelial cells by angiotensin 1–7

2013 ◽  
Vol 305 (1) ◽  
pp. L33-L41 ◽  
Author(s):  
Bruce D. Uhal ◽  
Hang Nguyen ◽  
MyTrang Dang ◽  
Indiwari Gopallawa ◽  
Jing Jiang ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Er Stress ◽  
Cathepsin D ◽  
Primary Cultures ◽  
A549 Cells ◽  
Surfactant Protein ◽  
Alveolar Epithelial Cells ◽  
Alveolar Epithelial ◽  
Induced Apoptosis ◽  
Jnk Activation

Earlier work showed that apoptosis of alveolar epithelial cells (AECs) in response to endogenous or xenobiotic factors is regulated by autocrine generation of angiotensin (ANG) II and its counterregulatory peptide ANG1–7. Mutations in surfactant protein C (SP-C) induce endoplasmic reticulum (ER) stress and apoptosis in AECs and cause lung fibrosis. This study tested the hypothesis that ER stress-induced apoptosis of AECs might also be regulated by the autocrine ANGII/ANG1–7 system of AECs. ER stress was induced in A549 cells or primary cultures of human AECs with the proteasome inhibitor MG132 or the SP-C BRICHOS domain mutant G100S. ER stress activated the ANGII-generating enzyme cathepsin D and simultaneously decreased the ANGII-degrading enzyme ACE-2, which normally generates the antiapoptotic peptide ANG1–7. TAPI-2, an inhibitor of ADAM17/TACE, significantly reduced both the activation of cathepsin D and the loss of ACE-2. Apoptosis of AECs induced by ER stress was measured by assays of mitochondrial function, JNK activation, caspase activation, and nuclear fragmentation. Apoptosis induced by either MG132 or the SP-C BRICHOS mutant G100S was significantly inhibited by the ANG receptor blocker saralasin and was completely abrogated by ANG1–7. Inhibition by ANG1–7 was blocked by the specific mas antagonist A779. These data show that ER stress-induced apoptosis is mediated by the autocrine ANGII/ANG1–7 system in human AECs and demonstrate effective blockade of SP-C mutation-induced apoptosis by ANG1–7. They also suggest that therapeutic strategies aimed at administering ANG1–7 or stimulating ACE-2 may hold potential for the management of ER stress-induced fibrotic lung disorders.

scholarly journals The role of Endoplasmic Reticulum (ER) stress in pulmonary fibrosis

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Martina Korfei ◽  
Clemens Ruppert ◽  
Benjamin Loeh ◽  
Poornima Mahavadi ◽  
Andreas Guenther
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cells ◽  
Er Stress ◽  
Replicative Senescence ◽  
Gene Mutations ◽  
Surfactant Protein ◽  
Alveolar Epithelial Cells ◽  
Gene Encoding ◽  
Alveolar Epithelial

AbstractThe activation of Endoplasmic Reticulum (ER) stress and Unfolded Protein Response (UPR) was first observed in patients with familial interstitial pneumonia (FIP) carrying mutations in the C-terminal BRICHOS domain of surfactant protein C (SFTPC). Here, aggresome formation and severe ER stress was demonstrated in type-II alveolar epithelial cells (AECII), which specifically express this very hydrophobic surfactant protein. In subsequent studies, FIP-patients with mutations in the gene encoding surfactant protein A2 (SFTPA2) were discovered, whose overexpression in epithelial cells in vitro also resulted in significant induction of ER stress. Moreover, prominent ER stress in AECII was also observed in FIP-patients not carrying the SFTPC/SFTPA2 mutations, as well as in patients with the more common sporadic forms of IP. Additionally, cases of adult-onset FIP with mutations in Telomerase genes and other telomereassociated components were reported. These mutations were associated with telomere shortening, which is a potential cause for triggering a persistent DNA damage response and replicative senescence in affected cells. Moreover, shortened telomeres were observed directly in the AECII of FIP-patients, and even sporadic IP cases, in the absence of any gene mutations. Here, we try to figure out the possible origins of ER stress in sporadic IP cases and non-SFTPC/SFTPA2-associated FIP.

Effect of endocytosis inhibitors on alveolar clearance of albumin, immunoglobulin G, and SP-A in rabbits

1994 ◽  
Vol 266 (5) ◽  
pp. L544-L552 ◽  
Author(s):  
R. H. Hastings ◽  
J. R. Wright ◽  
K. H. Albertine ◽  
R. Ciriales ◽  
M. A. Matthay
Keyword(s):  
Immunoglobulin G ◽  
Protein Transport ◽  
Protein A ◽  
Alveolar Epithelium ◽  
Alveolar Epithelial Cells ◽  
Capillary Endothelium ◽  
Alveolar Type ◽  
Protein Uptake ◽  
Alveolar Epithelial

Protein in the alveolar space may be cleared by endocytosis and degradation inside alveolar epithelial cells, by transcytosis across the alveolar epithelium, or by restricted diffusion through the epithelium. The relative contributions of these three pathways to clearance of large quantities of protein from the air spaces is not known. This study investigated the effects of monensin and nocodazole, agents which inhibit endocytosis in cell culture, on alveolar epithelial protein transport in anesthetized rabbits. There was evidence that monensin and nocodazole inhibited endocytosis by the alveolar epithelium in vivo. Nocodazole increased the number of vesicles in the alveolar epithelium and capillary endothelium. Monensin increased vesicle density in the endothelium. These results suggested that the inhibitors disrupted microtubules or interrupted cellular membrane traffic in the lung. Both inhibitors decreased lung parenchymal uptake of immunoreactive human albumin from the air spaces. Monensin and nocodazole inhibited albumin uptake in cultured alveolar type II cells. Monensin increased the amount of 125I-labeled surfactant protein A associated with the lungs, compared with the quantity remaining in the air space 2 h after instillation. Although the drugs decreased alveolar epithelial protein uptake, they did not decrease alveolar clearance of 125I-labeled immunoglobulin G or 131I-labeled albumin in anesthetized rabbits. Thus monensin- and nocodazole-sensitive protein-uptake pathways do not account for most alveolar protein clearance when the distal air spaces are filled with a protein solution.

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