Article

Expression and Localization of Lung Surfactant Protein A in Human Tissues

Department of Immunology and Microbiology, Institute of Medical Biology, University of Southern Denmark, Winsløwparken 21.1, DK-5000 Odense C, Denmark.
American Journal of Respiratory Cell and Molecular Biology (Impact Factor: 4.11). 12/2003; 29(5):591-7. DOI: 10.1165/rcmb.2002-0274OC
Source: PubMed

ABSTRACT Lung surfactant protein A (SP-A) is a collectin produced by alveolar type II cells and Clara cells. It binds to carbohydrate structures on microorganisms, initiating effector mechanisms of innate immunity and modulating the inflammatory response in the lung. Reverse transcriptase-polymerase chain reaction was performed on a panel of RNAs from human tissues for SP-A mRNA expression. The lung was the main site of synthesis, but transcripts were readily amplified from the trachea, prostate, pancreas, and thymus. Weak expression was observed in the colon and salivary gland. SP-A sequences derived from lung and thymus mRNA revealed the presence of both SP-A1 and SP-A2, whereas only SP-A2 expression was found in the trachea and prostate. Monoclonal antibodies were raised against SP-A and characterized. One of these (HYB 238-4) reacted in Western blotting with both reduced and unreduced SP-A, with N-deglycosylated and collagenase-treated SP-A, and with both recombinant SP-A1 and SP-A2. This antibody was used to demonstrate SP-A in immunohistochemistry of human tissues. Strong SP-A immunoreactivity was seen in alveolar type-II cells, Clara cells, and on and within alveolar macrophages, but no extrapulmonary SP-A immunoreactivity was observed. In contrast to lung surfactant protein D (SP-D), which is generally expressed on mucosal surfaces, SP-A seems to be restricted to the respiratory system.

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    • "Please cite this article as: Kaisani, A., et al., Branching morphogenesis of immortalized human bronchial epithelial cells in threedimensional culture. Differentiation (2014), http://dx.doi.org/10.1016/j.diff.2014.02.003i which is expressed in both Type II pneumocytes and Clara cells (Madsen et al., 2003). Although SP-A is expressed in HBEC3 KTs in 2D culture, expression of SP-A in 3D is more representative of its expression and secretion in vivo. "
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    ABSTRACT: While mouse models have contributed in our understanding of lung development, repair and regeneration, inherent differences between the murine and human airways requires the development of new models using human airway epithelial cells. In this study, we describe a three-dimensional model system using human bronchial epithelial cells (HBECs) cultured on reconstituted basement membrane. HBECs form complex budding and branching structures on reconstituted basement membrane when co-cultured with human lung fetal fibroblasts. These structures are reminiscent of the branching epithelia during lung development. The HBECs also retain markers indicative of epithelial cell types from both the central and distal airways suggesting their multipotent potential. In addition, we illustrate how the model can be utilized to understand respiratory diseases such as lung cancer. The 3D novel cell culture system recapitulates stromal-epithelial interactions in vitro that can be utilized to understand important aspects of lung development and diseases.
    Differentiation 05/2014; 87(3-4). DOI:10.1016/j.diff.2014.02.003 · 2.84 Impact Factor
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    • "Please cite this article as: Kaisani, A., et al., Branching morphogenesis of immortalized human bronchial epithelial cells in threedimensional culture. Differentiation (2014), http://dx.doi.org/10.1016/j.diff.2014.02.003i which is expressed in both Type II pneumocytes and Clara cells (Madsen et al., 2003). Although SP-A is expressed in HBEC3 KTs in 2D culture, expression of SP-A in 3D is more representative of its expression and secretion in vivo. "
    Differentiation 01/2014; · 2.84 Impact Factor
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    • "Although the bands for SP-A (33 kDa) in the kidney extracts were detected by Kankavi [21], SP-A mRNA was never detected in the renal tissues of mice [22,23] and humans. The current study presented the exact expressions of SP-A mRNA and protein in human renal tissues. "
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    ABSTRACT: Background Surfactant protein A (SP-A), encoded by two functional genes, SP-A1 and SP-A2, is essential for the inflammatory process and host defence in the lungs. Recent studies have demonstrated the extrapulmonary expression of SP-A. Similar to the lungs, the kidneys are organs exposed to external pathogens. The present study evaluated the expression and location of SP-A in the kidneys. The effect of lipopolysaccharide (LPS) on the expression of SP-A subtypes was also studied in renal tubular epithelial (HK-2) cells. Methods Immunohistochemical staining was performed using polyclonal antibody against SP-A. RT-PCR was also performed using mRNA from normal human renal tissues and HK-2 cells. The expressions of the SP-A1 and SP-A2 genes were determined by PCR-based RFLP analysis, gene-specific amplification, and direct sequencing of RT-PCR products. Western blot was conducted to analyse the SP-A protein. HK-2 cells were treated with LPS at various concentrations (0, 0.1, 1, 2, 5, and 10 μg/mL) for 8 h and at 5 μg/mL at various time points (0, 2, 4, 8, 16, and 24 h). The LPS-induced expressions of SP-A1 and SP-A2 mRNA and protein were analysed by RT-PCR and Western blot. Results SP-A was localised in the renal tubular epithelial cells in the proximal and distal convoluted tubules. SP-A1 and SP-A2 mRNA and protein were expressed in HK-2 cells and human renal tissues, which were significantly increased in time- and dose-dependent manners after LPS treatment (P < 0.05). Conclusions Human renal tubular epithelial cells can express both SP-A1 and SP-A2 genes, which may play important roles in the inflammatory modulation of the kidney.
    Journal of Inflammation 01/2013; 10(1):2. DOI:10.1186/1476-9255-10-2 · 2.22 Impact Factor
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