The human lung surfactant proteins A (SP-A) and D (SP-D) interact with apoptotic target cells by different binding mechanisms

Jäkel, Anne; Clark, Howard; Sim, Robert B.

doi:10.1016/j.imbio.2009.09.005

Cited by 32 publications

(37 citation statements)

References 46 publications

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“…SP-D binding to viable and early apoptotic neutrophils was inhibited by maltose and EDTA, suggesting lectin binding site involvement whereas the binding to late apoptotic neutrophils was predominantly Ca 2+ -independent. However, the surface molecules involved in these interactions were not identified in the previous study (Jäkel et al, 2010).…”

Section: Discussionmentioning

confidence: 80%

“…Recent evidence shows that SP-A and SP-D interact with apoptotic target cells in a very distinct manner (Jäkel et al, 2010). SP-A bound to viable and early apoptotic cells predominantly Ca 2+ -dependently but the interaction with late apoptotic cells was much greater and was Ca 2+ -independent, suggesting involvement of sites on SP-A other than the lectinor Ca 2+ -binding sites.…”

Section: Discussionmentioning

confidence: 99%

“…5A and 5B). Late apoptotic cells were identified as described previously (Jäkel et al, 2009). apoptotic neutrophils (Jäkel et al, 2010), but in the present binding assay biotinylated proteins were used in comparison to specific mAbs in the published results. The differences are likely to be due to biotinylation status of the proteins.…”

Section: Sp-a and Sp-d Inhibit The Binding Of Anti-mpo Mabs To Late Amentioning

confidence: 99%

“…Family members are pattern recognition molecules that bind nonself moieties, thereby targeting the foreign material for rapid clearance by immune cells. SP-A in particular can bind to a variety of substrates, including carbohydrates, surfactant lipids and lipid vesicles (Haagsman et al, 1990;Haagsman et al, 1991;Kuroki and Akino, 1991;Jäkel et al, 2010) and proteins (myosin) (Michelis et al, 1994). Binding of SP-A to both bacteria and lipid vesicles enhances their phagocytosis by macrophages (Gaynor et al, 1995;Wright and Youmans, 1995;Tino and Wright, 1999).…”

Section: Introductionmentioning

confidence: 99%

“…Jäkel and coworkers (Jäkel et al, 2010) show that SP-A and SP-D interact with late apoptotic Jurkat cells and neutrophils in a Ca 2+ -independent manner whereas the binding to viable and early apoptotic target cells for SP-A was Ca 2+ -dependent and inhibited by mannose (for both cell types). SP-D did not interact with viable and early apoptotic Jurkat cells at all but bound in a mixed mode (Ca 2+ -dependent or-independent) to viable and early apoptotic neutrophils.…”

Section: Introductionmentioning

confidence: 99%

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Surface-bound myeloperoxidase is a ligand for recognition of late apoptotic neutrophils by human lung surfactant proteins A and D

et al. 2010

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Surfactant proteins A (SP-A) and D (SP-D), both members of the collectin family, play a well established role in apoptotic cell recognition and clearance. Recent in vitro data show that SP-A and SP-D interact with apoptotic neutrophils in a distinct manner. SP-A and SP-D bind in a Ca 2+ -dependent manner to viable and early apoptotic neutrophils whereas the much greater interaction with late apoptotic neutrophils is Ca 2+ -independent. Cell surface molecules on the apoptotic target cells responsible for these interactions had not been identified and this study was done to find candidate target molecules. Myeloperoxidase (MPO), a specific intracellular defense molecule of neutrophils that becomes exposed on the outside of the cell upon apoptosis, was identified by affinity purification, mass-spectrometry and western blotting as a novel binding molecule for SP-A and SP-D. To confirm its role in recognition, it was shown that purified immobilised MPO binds SP-A and SP-D, and that MPO is surface-exposed on late apoptotic neutrophils. SP-A and SP-D inhibit binding of an anti-MPO monoclonal Ab to late apoptotic cells. Fluorescence microscopy confirmed that anti-MPO mAb and SP-A/SP-D colocalise on late apoptotic neutrophils. Desmoplakin was identified as a further potential ligand for SP-A, and neutrophil defensin as a target for both proteins.

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Section: Discussionmentioning

confidence: 80%

Section: Discussionmentioning

confidence: 99%

Section: Sp-a and Sp-d Inhibit The Binding Of Anti-mpo Mabs To Late Amentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Surface-bound myeloperoxidase is a ligand for recognition of late apoptotic neutrophils by human lung surfactant proteins A and D

et al. 2010

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Novel role of surfactant protein A in bacterial sinusitis

Noutsios

Willis

Ledford

et al. 2017

Int Forum Allergy Rhinol

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Background Chronic rhinosinusitis (CRS) is a common inflammatory disorder of the upper airway characterized by chronic inflammation and significant sinonasal remodeling. CRS has two major subgroups based on whether polyps are present or absent. In some cases, it is characterized by colonization with opportunistic pathogens such as Pseudomonas aeruginosa (PA), Staphylococcus aureus and other bacteria. The innate immune system of the sinonasal epithelium is the first line of defense against inhaled pathogens. Surfactant protein A (SP-A) is a member of the collectin family secreted by the airway epithelia that plays a critical role in airway innate immunity, as it can aggregate bacteria. We hypothesized that SP-A plays a role in bacterial CRS. Methods Air-liquid-interface (ALI) cultures of nasal epithelial cells were derived from human ex vivo healthy and CRS sinus tissues (n=26) and challenged with PA. SP-A levels were measured with Western Blot and qRT-PCR in ALI and sinus tissues. Results We determined that SP-A i) mRNA and protein levels are significantly increased in CRS tissues compared to healthy sinuses; ii) although primary expressed in the lung, it is also synthesized and expressed in sinonasal epithelia; ii) is expressed in the sinuses of an SP-A humanized transgenic mouse but not in SP-A knock-out mouse; iv) mRNA levels are upregulated significantly during PA challenge, but protein levels are downregulated 4h post challenge and upregulated at 12h. Conclusions Our data suggest that SP-A is expressed in the sinuses and it plays a role in the sinus innate immune responses during bacterial infections.

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Unraveling the enigma: The emerging significance of pulmonary surfactant proteins in predicting, diagnosing, and managing COVID‐19

Bastani,

Jalilian

2024

Immunity Inflam & Disease

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BackgroundSevere cases of COVID‐19 often lead to the development of acute respiratory syndrome, a critical condition believed to be caused by the harmful effects of SARS‐CoV‐2 on type II alveolar cells. These cells play a crucial role in producing pulmonary surfactants, which are essential for proper lung function. Specifically focusing on surfactant proteins, including Surfactant protein A (SP‐A), Surfactant protein B, Surfactant protein C, and Surfactant protein D (SP‐D), changes in the levels of pulmonary surfactants may be a significant factor in the pathological changes seen in COVID‐19 infection.ObjectiveThis study aims to gain insights into surfactants, particularly their impacts and changes during COVID‐19 infection, through a comprehensive review of current literature. The study focuses on the function of surfactants as prognostic markers, diagnostic factors, and essential components in the management and treatment of COVID‐19.FindingIn general, pulmonary surfactants serve to reduce the surface tension at the gas–liquid interface, thereby significantly contributing to the regulation of respiratory mechanics. Additionally, these surfactants play a crucial role in the innate immune system within the pulmonary microenvironment. Within the spectrum of COVID‐19 infections, a compelling association is observed, characterized by elevated levels of SP‐D and SP‐A across a range of manifestations from mild to severe pneumonia. The sudden decline in respiratory function observed in COVID‐19 patients may be attributed to the decreased synthesis of surfactants by type II alveolar cells.ConclusionCollectin proteins such as SP‐A and SP‐D show promise as biomarkers, offering potential avenues for predicting and monitoring pulmonary alveolar injury in the context of COVID‐19. This clarification enhances our understanding of the molecular complexities contributing to respiratory complications in severe COVID‐19 cases, providing a foundation for targeted therapeutic approaches using surfactants and refined clinical management strategies.

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The human lung surfactant proteins A (SP-A) and D (SP-D) interact with apoptotic target cells by different binding mechanisms

Cited by 32 publications

References 46 publications

Surface-bound myeloperoxidase is a ligand for recognition of late apoptotic neutrophils by human lung surfactant proteins A and D

Surface-bound myeloperoxidase is a ligand for recognition of late apoptotic neutrophils by human lung surfactant proteins A and D

Novel role of surfactant protein A in bacterial sinusitis

Unraveling the enigma: The emerging significance of pulmonary surfactant proteins in predicting, diagnosing, and managing COVID‐19

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