scholarly journals The Significance of KL-6 as Prognosis Monitoring Biomarker in Patients With Severe COVID-19 From Stabilized Stage Toward Convalescence

2021 ◽  
Author(s):  
Long He ◽  
Liu Lu ◽  
Ming Zong ◽  
Huang Zhou ◽  
Lan Wang ◽  
...  
Keyword(s):  
Lung Injury ◽  
Protein A ◽  
Alveolar Epithelium ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Monocyte Count ◽  
Type Ii ◽  
Tnf Α ◽  
Ifn Γ ◽  
Blood Routine

Abstract Background: This study aims to identify some biomarkers for monitoring the recovery of lung injury in severe COVID-19 patients from stabilized stage toward convalescence.Methods: We enrolled participants who diagnosed with severe COVID-19 (n = 28) and health volunteers (n = 25) from Taikang Tongji (Wuhan) Hospital. The patients were in a stabilized stage and had a course of 48.1±12.8 days. We followed these patients for 90 days. The blood routine, cytokines (IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p70, IL-17A, TNF-α, IFN-α, IFN-γ), type II alveolar epithelium injury indicators (Surfactant protein A (SP-A), Krebs von den Lungen-6 (KL-6)) and chest CT were tested on the 1, 30, 60, and 90 days after enrollment. Results: In stabilized stage, the parameters of blood routine and some cytokines (IL-1β, IL-2, IL-4, IL-12p70, TNF-α) had bounced back to normal (p>0.05). Some cytokines (IL-5, IL-6, IL-10, IL-17A, IFN-α, IFN-γ) and type II alveolar epithelium injury indicators (SP-A and KL-6) were still higher than normal (p<0.05). During the stabilized stage to convalescence, in spite of the variation of monocyte count, monocyte/lymphocyte ratio, IL-5, IL-10, IL-12p70, IL-17A, IFN-γ, IFN-α, SP-A and KL-6 were downward trend (p<0.05), only KL-6 level (p<0.05) could simultaneously reflect the lung injury volume which be measured by CT. Conclusions: Our preliminary data indicated that KL-6 could be an effective prognostic biomarker for monitoring the recovery of lung function in patients with severe COVID-19 from stabilized stage toward convalescence.

scholarly journals Role of the PI3-kinase signaling pathway in trafficking of the surfactant protein A receptor P63 (CKAP4) on type II pneumocytes

2010 ◽  
Vol 299 (6) ◽  
pp. L794-L807 ◽  
Author(s):  
Altaf S. Kazi ◽  
Jian-Qin Tao ◽  
Sheldon I. Feinstein ◽  
Li Zhang ◽  
Aron B. Fisher ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Protein A ◽  
Surfactant Protein ◽  
Pi3 Kinase ◽  
Surfactant Protein A ◽  
Type Ii Cells ◽  
Type Ii ◽  
Type Ii Pneumocytes ◽  
Kinase Signaling Pathway ◽  
Stimulation Of

Surfactant protein A (SP-A) plays an important role in the maintenance of lung lipid homeostasis. Previously, an SP-A receptor, P63 (CKAP4), on type II pneumocyte plasma membranes (PM) was identified by chemical cross-linking techniques. An antibody to P63 blocked the specific binding of SP-A to pneumocytes and the ability of SP-A to regulate surfactant secretion. The current report shows that another biological activity of SP-A, the stimulation of surfactant uptake by pneumocytes, is inhibited by P63 antibody. cAMP exposure resulted in enrichment of P63 on the cell surface as shown by stimulation of SP-A binding, enhanced association of labeled P63 antibody with type II cells, and promotion of SP-A-mediated liposome uptake, all of which were inhibited by competing P63 antibody. Incubation of A549 and type II cells with SP-A also increased P63 localization on the PM. The phosphatidylinositol 3-kinase (PI3-kinase) signaling pathway was explored as a mechanism for the transport of this endoplasmic reticulum (ER)-resident protein to the PM. Treatment with LY-294002, an inhibitor of the PI3-kinase pathway, prevented the SP-A-induced PM enrichment of P63. Exposure of pneumocytes to SP-A or cAMP activated Akt (PKB). Blocking either PI3-kinase or Akt altered SP-A-mediated lipid turnover. The data demonstrate an important role for the PI3-kinase-Akt pathway in intracellular transport of P63. The results add to the growing body of evidence that P63 is critical for SP-A receptor-mediated interactions with type II pneumocytes and the resultant regulation of surfactant turnover.

Exposure of surfactant protein A to ozone in vitro and in vivo impairs its interactions with alveolar cells

1992 ◽  
Vol 262 (1) ◽  
pp. L63-L68 ◽  
Author(s):  
R. S. Oosting ◽  
J. F. Van Iwaarden ◽  
L. Van Bree ◽  
J. Verhoef ◽  
L. M. Van Golde ◽  
...  
Keyword(s):  
Superoxide Anion ◽  
Protein A ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Alveolar Type ◽  
Type Ii ◽  
Superoxide Anion Production ◽  
Anion Production

This study focused on the question of whether exposure of surfactant protein A (SP-A) to ozone affected properties of this protein that may be involved in regulating alveolar type II cell and alveolar macrophage functions. In vitro exposure of human or canine SP-A to ozone reduced the ability of this protein to inhibit phorbol-ester induced secretion of [3H]phosphatidylcholine by alveolar type II cells in culture. Ozone-exposed human SP-A showed a decreased ability to enhance phagocytosis of herpes simplex virus and to stimulate superoxide anion production by alveolar macrophages. Experiments with elastase showed that ozone-exposed canine SP-A was more susceptible to proteolysis. A conformational change of the protein could underlie this phenomenon. Surfactant isolated from ozone-exposed rats (0.4 ppm ozone for 12 h) was also less able to stimulate superoxide anion production by alveolar macrophages than surfactant from control rats, which suggested that SP-A in vivo was also susceptible to ozone. The results of this study suggest that SP-A-alveolar cell interactions can be inhibited by ozone exposure, which may contribute to the toxicity of ozone in the lungs.

Identification and characterization of p63 (CKAP4/ERGIC-63/CLIMP-63), a surfactant protein A binding protein, on type II pneumocytes

2006 ◽  
Vol 291 (3) ◽  
pp. L436-L446 ◽  
Author(s):  
Nisha Gupta ◽  
Yefim Manevich ◽  
Altaf S. Kazi ◽  
Jian-Qin Tao ◽  
Aron B. Fisher ◽  
...  
Keyword(s):  
Binding Protein ◽  
Protein A ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Type Ii Cells ◽  
Receptor Complex ◽  
Type Ii ◽  
Surface Binding ◽  
Intact Mouse ◽  
The Cross

Surfactant protein A (SP-A) binds to alveolar type II cells through a specific high-affinity cell membrane receptor, although the molecular nature of this receptor is unclear. In the present study, we have identified and characterized an SP-A cell surface binding protein by utilizing two chemical cross-linkers: profound sulfo-SBED protein-protein interaction reagent and dithiobis(succinimidylpropionate) (DSP). Sulfo-SBED-biotinylated SP-A was cross-linked to the plasma membranes isolated from rat type II cells, and the biotin label was transferred from SP-A to its receptor by reduction. The biotinylated SP-A-binding protein was identified on blots by using streptavidin-labeled horseradish peroxidase. By using DSP, we cross-linked SP-A to intact mouse type II cells and immunoprecipitated the SP-A-receptor complex using anti-SP-A antibody. Both of the cross-linking approaches showed a major band of 63 kDa under reduced conditions that was identified as the rat homolog of the human type II transmembrane protein p63 (CKAP4/ERGIC-63/CLIMP-63) by matrix-assisted laser desorption ionization and nanoelectrospray tandem mass spectrometry of tryptic fragments. Thereafter, we confirmed the presence of p63 protein in the cross-linked SP-A-receptor complex by immunoprobing with p63 antibody. Coimmunoprecipitation experiments and functional assays confirmed specific interaction between SP-A and p63. Antibody to p63 could block SP-A-mediated inhibition of ATP-stimulated phospholipid secretion. Both intracellular and membrane localized pools of p63 were detected on type II cells by immunofluorescence and immunobloting. p63 colocalized with SP-A in early endosomes. Thus p63 closely interacts with SP-A and may play a role in the trafficking or the biological function of the surfactant protein.

Pulmonary surfactant protein A-mediated uptake of phosphatidylcholine by alveolar type II cells

1993 ◽  
Vol 265 (2) ◽  
pp. L193-L199 ◽  
Author(s):  
A. Tsuzuki ◽  
Y. Kuroki ◽  
T. Akino
Keyword(s):  
Pulmonary Surfactant ◽  
Protein A ◽  
Lamellar Body ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Alveolar Type ◽  
Type Ii Cells ◽  
Type Ii ◽  
Lamellar Bodies ◽  
Pulmonary Surfactant Protein

Pulmonary surfactant protein A (SP-A)-mediated uptake of phosphatidylcholine (PC) by alveolar type II cells was investigated. SP-A enhanced the uptake of liposomes containing dipalmitoylphosphatidylcholine (DPPC), 1-palmitoyl-2-linoleoyl phosphatidylcholine (PLPC), or 1,2-dihexadecyl-sn-glycero-3-phosphocholine (DPPC-ether), a diether analogue of DPPC, but about twice as much DPPC was taken up by type II cells as PLPC or DPPC-ether. When subcellular distribution was analyzed, 51.3 +/- 2.9% (mean +/- SD, n = 3) of cell-associated radiolabeled DPPC was recovered in the lamellar body-rich fraction in the presence of SP-A, whereas only 19.3 +/- 1.9% (mean +/- SD, n = 3) was found to this fraction in the absence of SP-A. When type II cells were incubated either with DPPC at 0 degree C or with DPPC-ether at 37 degrees C, or no cells were included, low proportions of the cell-associated lipids were present in the fractions corresponding to lamellar bodies even in the presence of SP-A. Anti-SP-A antibody significantly reduced the radioactivity incorporated into the lamellar body fraction. Phosphatidylcholine that had been incorporated into lamellar bodies remained largely intact when SP-A was present. Subcellular fractionations of type II cells with radiolabeled SP-A and DPPC revealed that the sedimentation characteristics of cell-associated SP-A are different from those of DPPC, although a small broad peak of radiolabeled SP-A was found in the lamellar body fraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Transcriptional activation and protein binding by two regions of the rat surfactant protein A promoter

1999 ◽  
Vol 277 (1) ◽  
pp. L134-L141
Author(s):  
Elizabeth Rosenberg ◽  
Feng Li ◽  
Candyce I. Smith ◽  
Samuel R. Reisher ◽  
Sheldon I. Feinstein
Keyword(s):  
Cell Line ◽  
Cell Lines ◽  
Promoter Activity ◽  
Protein A ◽  
Surfactant Protein ◽  
Clara Cell ◽  
Surfactant Protein A ◽  
Type Ii ◽  
Recognition Element ◽  
Type Ii Cell

Surfactant protein A (SP-A) is expressed in lung alveolar type II cells and bronchiolar Clara cells. We have identified two active regions in the promoter of the rat SP-A gene by deletion analysis of a plasmid containing 163 bp before the start of transcription (−163 bp), linked to a reporter gene. Constructs were transfected into lung cell lines derived from each of the cell types that produces SP-A. We found a novel region of promoter activity at ∼90 bp before the transcriptional start (SP-A−90). Mutation of four nucleotides in SP-A−90 that are highly conserved among species (−92 to −89 bp) decreased expression of the SP-A construct by ∼50% in both cell lines. Electrophoretic mobility shift analysis showed specific binding to SP-A−90 by nuclear proteins from the cell lines, as well as from rat lung and liver. The electrophoretic mobility of the bands shifted by lung nuclear proteins changed late in fetal development. Although in the Clara cell line no reduction of promoter activity was seen on deletion of the region upstream of SP-A−90, in the type II cell line, deletion of residues −163 to −133 did reduce activity by ∼50%. This region contains a recognition element for thyroid transcription factor-1 (TTF-1). Endogenous TTF-1 binding activity was substantially higher in the type II cell line than in the Clara cell line, but cotransfection of a TTF-1 expression plasmid enhanced expression of the SP-A construct better in the Clara cell line than in the type II cell line. These results suggest that the recognition element for TTF-1 has varying activity in the lung cell lines of different origin due to the availability of TTF-1.

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