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Yin X, Wang B, Yan Z, Hu L, Zhang X. Association between SP-A rs1965708 gene polymorphism and allergic rhinitis risk in Chinese population. J Clin Lab Anal 2021; 35:e23828. [PMID: 34028080 PMCID: PMC8274983 DOI: 10.1002/jcla.23828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/24/2021] [Accepted: 05/03/2021] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Pulmonary surfactant protein A (SP-A) in the respiratory tract plays an important role in host. In the present, we assessed the association between SP-A gene polymorphism and allergic rhinitis. METHODS Using a case-control design, we compared the genotype frequencies of SP-A rs1965708 between allergic rhinitis patients and healthy control group. Genotyping was performed using real-time quantitative PCR-based molecular identification methods. Univariate and multivariate logistic regression were performed to quantitatively assess the association between rs1965708 polymorphism and allergic rhinitis, and the odds ratio (OR) and 95% confidence interval (CI) were also calculated. RESULTS 500 patients with allergic rhinitis and 500 healthy controls were included in the study. Compared with the CC genotype, we found that AA genotype of rs1965708 could increase the allergic rhinitis risk in the univariate analysis (OR = 2.63, 95% CI: 1.56-4.54, p = 0.000). For dominant model, we found no significant difference in the dominant model (OR = 1.14, 95% CI: 0.86-1.52, p = 0.367). In the recessive model, the CC genotype could elevate the risk of allergic rhinitis compared with CC + AA genotype (OR = 2.70, 95% CI: 1.61-4.54, p = 0.000). Similar results were also found in the allele model (OR = 1.28, 95% CI: 1.07-1.54, p = 0.008). Interactions between rs1965708 AA or AC and smoking increased the allergic rhinitis risk. CONCLUSIONS The rs1965708 variants of SP-A gene polymorphism are associated with allergic rhinitis, and the A allele could increase the allergic rhinitis risk. The AA SNP variants that interact with smoking may alter the susceptibility to allergic rhinitis.
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Affiliation(s)
- Xinghong Yin
- Department of Otolaryngology-Head & Neck Surgery, Fuyang People's Hospital, Fuyang, China
| | - Bo Wang
- Department of Otolaryngology-Head & Neck Surgery, Fuyang People's Hospital, Fuyang, China
| | - Zhiqiang Yan
- Department of Otolaryngology-Head & Neck Surgery, Fuyang People's Hospital, Fuyang, China
| | - Lulu Hu
- Department of Otolaryngology-Head & Neck Surgery, Fuyang People's Hospital, Fuyang, China
| | - Xinhai Zhang
- Department of Otolaryngology-Head & Neck Surgery, Fuyang People's Hospital, Fuyang, China
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Thorenoor N, Kawasawa YI, Gandhi CK, Zhang X, Floros J. Differential Impact of Co-expressed SP-A1/SP-A2 Protein on AM miRNome; Sex Differences. Front Immunol 2019; 10:1960. [PMID: 31475015 PMCID: PMC6707024 DOI: 10.3389/fimmu.2019.01960] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 08/02/2019] [Indexed: 12/04/2022] Open
Abstract
In humans there are two surfactant protein A (SP-A) functional genes SFTPA1 and SFTPA2 encoding innate immune molecules, SP-A1 and SP-A2, respectively, with numerous genetic variants each. SP-A interacts and regulates many of the functions of alveolar macrophages (AM). It is shown that SP-A variants differ in their ability to regulate the AM miRNome in response to oxidative stress (OxS). Because humans have both SP-A gene products, we were interested to determine the combined effect of co-expressed SP-A1/SP-A2 (co-ex) in response to ozone (O3) induced OxS on AM miRNome. Human transgenic (hTG) mice, carrying both SP-A1/SP-A2 (6A2/1A0, co-ex) and SP-A- KO were utilized. The hTG and KO mice were exposed to filtered air (FA) or O3 and miRNA levels were measured after AM isolation with or without normalization to KO. We found: (i) The AM miRNome of co-ex males and females in response to OxS to be largely downregulated after normalization to KO, but after Bonferroni multiple comparison analysis only in females the AM miRNome remained significantly different compared to control (FA); (ii) The targets of the significantly changed miRNAs were downregulated in females and upregulated in males; (iii) Several of the validated mRNA targets were involved in pro-inflammatory response, anti-apoptosis, cell cycle, cellular growth and proliferation; (iv) The AM of SP-A2 male, shown, previously to have major effect on the male AM miRNome in response to OxS, shared similarities with the co-ex, namely in pathways involved in the pro-inflammatory response and anti-apoptosis but also exhibited differences with the cell-cycle, growth, and proliferation pathway being involved in co-ex and ROS homeostasis in SP-A2 male. We speculate that the presence of both gene products vs. single gene products differentially impact the AM responses in males and females in response to OxS.
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Affiliation(s)
- Nithyananda Thorenoor
- Department of Pediatrics, Center for Host Defense, Inflammation, and Lung Disease Research, The Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Yuka Imamura Kawasawa
- Departments of Pharmacology and Biochemistry and Molecular Biology, Institute for Personalized Medicine, The Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Chintan K Gandhi
- Department of Pediatrics, Center for Host Defense, Inflammation, and Lung Disease Research, The Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Xuesheng Zhang
- Department of Pediatrics, Center for Host Defense, Inflammation, and Lung Disease Research, The Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Joanna Floros
- Department of Pediatrics, Center for Host Defense, Inflammation, and Lung Disease Research, The Pennsylvania State University College of Medicine, Hershey, PA, United States.,Department of Obstetrics and Gynecology, The Pennsylvania State University College of Medicine, Hershey, PA, United States
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3
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Wang G, Umstead TM, Hu S, Mikerov AN, Phelps DS, Floros J. Differential Effects of Human SP-A1 and SP-A2 on the BAL Proteome and Signaling Pathways in Response to Klebsiella pneumoniae and Ozone Exposure. Front Immunol 2019; 10:561. [PMID: 30972061 PMCID: PMC6443908 DOI: 10.3389/fimmu.2019.00561] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Accepted: 03/04/2019] [Indexed: 12/29/2022] Open
Abstract
Surfactant protein A (SP-A) plays critical roles in host defense, regulation of inflammation and surfactant metabolism in the lung. The human SP-A locus consists of two functional genes, SFTPA1 and SFTPA2 encoding surfactant proteins SP-A1 and SP-A2, respectively. Structural and functional differences exist between SP-A1 and SP-A2 in vitro and in vivo. Ozone is a major air pollutant with a negative impact on many biological processes. In this study we used humanized transgenic (hTG) SP-A1 and SP-A2 mice, and SP-A KO mice to study in vivo effects of SP-A1 and SP-A2 on the bronchoalveolar lavage (BAL) proteomic profile and associated signaling pathways in response to ozone or filtered air (FA) exposure and Klebsiella pneumoniae infection. The BAL samples were harvested 24 h after ozone (2 ppm for 3 h) or FA exposure and infection and analyzed by two-dimensional difference gel electrophoresis (2D-DIGE) and MALDI-ToF/ToF. We found: that (1) Ozone exposure, but not infection, is a major factor for increases in total BAL protein content. (2) A total of 36 proteins were identified, accounting for 89.62% of the BAL proteins resolved by the 2D-DIGE system. (3) The number of proteins in which levels were altered more than 25% following infection and FA exposure was: SP-A2 > SP-A1 > KO for male mice, and SP-A2 ≈ SP-A1 > KO for female mice. (4) The number of proteins with more than 25% increase/decrease after ozone exposure and infection was: SP-A2 > SP-A1 ≈ KO, with the majority being increases in male mice and decreases in female mice. (5) Eleven out of the 36 proteins, including annexin A5, glutathione S-transferase A4, SP-A1/SP-A2, and 14-3-3 zeta protein, exhibited significant differences among SP-A genotypes. The acute phase response (APR) that includes the NF-kB signaling pathway plays a critical role, followed by Nrf2-mediated oxidative response, and others. These associated with SP-A genotype, sex, and ozone-induced oxidative stress in response to infection. We concluded that human SP-A2 and SP-A1 exhibit differential genotype-and sex-dependent innate immune responses to microbial pathogens and/or ozone-induced oxidative stress by modulating proteomic patterns and signaling pathways in the lung.
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Affiliation(s)
- Guirong Wang
- Department of Pediatrics, Center for Host defense, Inflammation, and Lung Disease (CHILD) Research, The Pennsylvania State University College of Medicine, Hershey, PA, United States.,Department of Surgery, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Todd M Umstead
- Department of Pediatrics, Center for Host defense, Inflammation, and Lung Disease (CHILD) Research, The Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Sanmei Hu
- Department of Pediatrics, Center for Host defense, Inflammation, and Lung Disease (CHILD) Research, The Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Anatoly N Mikerov
- Department of Pediatrics, Center for Host defense, Inflammation, and Lung Disease (CHILD) Research, The Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - David S Phelps
- Department of Pediatrics, Center for Host defense, Inflammation, and Lung Disease (CHILD) Research, The Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Joanna Floros
- Department of Pediatrics, Center for Host defense, Inflammation, and Lung Disease (CHILD) Research, The Pennsylvania State University College of Medicine, Hershey, PA, United States.,Department of Obstetrics and Gynecology, The Pennsylvania State University College of Medicine, Hershey, PA, United States
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Stoeckelhuber M, Feuerhake F, Schmitz C, Wolff KD, Kesting MR. Immunolocalization of Surfactant Proteins SP-A, SP-B, SP-C, and SP-D in Infantile Labial Glands and Mucosa. J Histochem Cytochem 2018; 66:531-538. [PMID: 29601229 PMCID: PMC6055263 DOI: 10.1369/0022155418766063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 02/16/2018] [Indexed: 11/22/2022] Open
Abstract
Surfactant proteins in different glandular structures of the oral cavity display antimicrobial activity for protection of invading microorganisms. Moreover, they are involved in lowering liquid tension in fluids and facilitate secretion flows. Numerous investigations for studying the occurrence of surfactant proteins in glandular tissues were performed using different methods. In the oral cavity, minor salivary glands secrete saliva continuously for the maintenance of a healthy oral environment. For the first time, we could show that infantile labial glands show expression of the surfactant proteins (SP) SP-A, SP-B, SP-C, and SP-D in acinar cells and the duct system in different intensities. The stratified squamous epithelium of the oral mucosa revealed positive staining for SPs in various cell layers.
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Affiliation(s)
- Mechthild Stoeckelhuber
- Department of Oral and Maxillofacial Surgery, Technical University of Munich, Munich, Germany
| | - Friedrich Feuerhake
- Department of Neuropathology, Institute of Pathology, Hannover Medical School, Hannover, Germany
| | - Christoph Schmitz
- Chair of Neuroanatomy, Institute of Anatomy, Faculty of Medicine, Ludwig Maximilians University of Munich, Munich, Germany
| | - Klaus-Dietrich Wolff
- Department of Oral and Maxillofacial Surgery, Technical University of Munich, Munich, Germany
| | - Marco R. Kesting
- Department of Oral and Maxillofacial Surgery, Technical University of Munich, Munich, Germany
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Bassorgun CI, Sayar EC, Baykara M, Kankavi O. Alteration of surfactant protein A expression in renal cell carcinoma. Biotech Histochem 2018; 93:519-525. [PMID: 29932013 DOI: 10.1080/10520295.2018.1472296] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Surfactant protein-A (SP-A) belongs to a family of collagen-containing C-type lectins called collectins. SP-A is expressed by renal tubule epithelial cells. We investigated the distribution of SP-A in renal cell carcinomas (RCC) using immunohistochemical techniques and western blotting. We used 35 formalin fixed, paraffin embedded (FFPE) RCC tissue samples. We compared results with clinico-pathological parameters of RCC including age, sex, Fuhrman grade, tumor volume, tumor node metastasis (TNM) and clinical stage. SP-A was localized in the glomerulus and renal tubule epithelium in nontumor tissue and strong SP-A immunoreactivity was observed in tumor tissue. SP-A was expressed in the RCC tumor cells (64%) and nontumor cells (34%) in males and RCC tumor cells (90%) and nontumor cells (30%) in females. There was a significant correlation between SP-A immunoreactivity in tumor cells and gender, age, tumor diameter, Fuhrman grade and tumor diameter. Western blot analysis supported the immunohistochemical findings. We present evidence for involvement of SP-A in RCC and suggest that increased SP-A expression in RCC is associated with favorable prognosis.
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Affiliation(s)
- C I Bassorgun
- a Departments of Pathology, Faculty of Medicine , University of Akdeniz , Antalya , Turkey
| | - E C Sayar
- a Departments of Pathology, Faculty of Medicine , University of Akdeniz , Antalya , Turkey
| | - M Baykara
- b Department of Urology, Faculty of Medicine , University of Akdeniz , Antalya , Turkey
| | - O Kankavi
- c Department of Biochemistry, Faculty of Veterinary Medicine , The University of Mehmet Akif Ersoy , Burdur , Turkey
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Abstract
Submucosal glands contribute to airway surface liquid (ASL), a film that protects all airway surfaces. Glandular mucus comprises electrolytes, water, the gel-forming mucin MUC5B, and hundreds of different proteins with diverse protective functions. Gland volume per unit area of mucosal surface correlates positively with impaction rate of inhaled particles. In human main bronchi, the volume of the glands is ∼ 50 times that of surface goblet cells, but the glands diminish in size and frequency distally. ASL and its trapped particles are removed from the airways by mucociliary transport. Airway glands have a tubuloacinar structure, with a single terminal duct, a nonciliated collecting duct, then branching secretory tubules lined with mucous cells and ending in serous acini. They allow for a massive increase in numbers of mucus-producing cells without replacing surface ciliated cells. Active secretion of Cl(-) and HCO3 (-) by serous cells produces most of the fluid of gland secretions. Glands are densely innervated by tonically active, mutually excitatory airway intrinsic neurons. Most gland mucus is secreted constitutively in vivo, with large, transient increases produced by emergency reflex drive from the vagus. Elevations of [cAMP]i and [Ca(2+)]i coordinate electrolyte and macromolecular secretion and probably occur together for baseline activity in vivo, with cholinergic elevation of [Ca(2+)]i being mainly responsive for transient increases in secretion. Altered submucosal gland function contributes to the pathology of all obstructive diseases, but is an early stage of pathogenesis only in cystic fibrosis.
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Affiliation(s)
- Jonathan H Widdicombe
- Department of Physiology and Membrane Biology, University of California-Davis, Davis, California; and Department of Psychology and Cystic Fibrosis Research Laboratory, Stanford University, Stanford, California
| | - Jeffrey J Wine
- Department of Physiology and Membrane Biology, University of California-Davis, Davis, California; and Department of Psychology and Cystic Fibrosis Research Laboratory, Stanford University, Stanford, California
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7
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Understanding Idiopathic Interstitial Pneumonia: A Gene-Based Review of Stressed Lungs. BIOMED RESEARCH INTERNATIONAL 2015; 2015:304186. [PMID: 26539479 PMCID: PMC4619788 DOI: 10.1155/2015/304186] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 08/26/2015] [Indexed: 12/17/2022]
Abstract
Pulmonary fibrosis is the main cause of severe morbidity and mortality in idiopathic interstitial pneumonias (IIP). In the past years, there has been major progress in the discovery of genetic factors that contribute to disease. Genes with highly penetrant mutations or strongly predisposing common risk alleles have been identified in familial and sporadic IIP. This review summarizes genes harbouring causative rare mutations and replicated common predisposing alleles. To date, rare mutations in nine different genes and five risk alleles fulfil this criterion. Mutated genes represent three genes involved in surfactant homeostasis and six genes involved in telomere maintenance. We summarize gene function, gene expressing cells, and pathological consequences of genetic alterations associated with disease. Consequences of the genetic alteration include dysfunctional surfactant processing, ER stress, immune dysregulation, and maintenance of telomere length. Biological evidence shows that these processes point towards a central role for alveolar epithelial type II cell dysfunction. However, tabulation also shows that function and consequence of most common risk alleles are not known. Most importantly, the predisposition of the MUC5B risk allele to disease is not understood. We propose a mechanism whereby MUC5B decreases surface tension lowering capacity of alveolar surfactant at areas with maximal mechanical stress.
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8
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Singh SP, Gundavarapu S, Smith KR, Chand HS, Saeed AI, Mishra NC, Hutt J, Barrett EG, Husain M, Harrod KS, Langley RJ, Sopori ML. Gestational exposure of mice to secondhand cigarette smoke causes bronchopulmonary dysplasia blocked by the nicotinic receptor antagonist mecamylamine. ENVIRONMENTAL HEALTH PERSPECTIVES 2013; 121:957-64. [PMID: 23757602 PMCID: PMC3734504 DOI: 10.1289/ehp.1306611] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 06/07/2013] [Indexed: 05/10/2023]
Abstract
BACKGROUND Cigarette smoke (CS) exposure during gestation may increase the risk of bronchopulmonary dysplasia (BPD)-a developmental lung condition primarily seen in neonates that is characterized by hypoalveolarization, decreased angiogenesis, and diminished surfactant protein production and may increase the risk of chronic obstructive pulmonary disease. OBJECTIVE We investigated whether gestational exposure to secondhand CS (SS) induced BPD and sought to ascertain the role of nicotinic acetylcholine receptors (nAChRs) in this response. METHODS We exposed BALB/c and C57BL/6 mice to filtered air (control) or SS throughout the gestation period or postnatally up to 10 weeks. Lungs were examined at 7 days, 10 weeks, and 8 months after birth. RESULTS Gestational but not postnatal exposure to SS caused a typical BPD-like condition: suppressed angiogenesis [decreased vascular endothelial growth factor (VEGF), VEGF receptor, and CD34/CD31 (hematopoietic progenitor cell marker/endothelial cell marker)], irreversible hypoalveolarization, and significantly decreased levels of Clara cells, Clara cell secretory protein, and surfactant proteins B and C, without affecting airway ciliated cells. Importantly, concomitant exposure to SS and the nAChR antagonist mecamylamine during gestation blocked the development of BPD. CONCLUSIONS Gestational exposure to SS irreversibly disrupts lung development leading to a BPD-like condition with hypoalveolarization, decreased angiogenesis, and diminished lung secretory function. Nicotinic receptors are critical in the induction of gestational SS-induced BPD, and the use of nAChR antagonists during pregnancy may block CS-induced BPD.
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Affiliation(s)
- Shashi P Singh
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico, USA
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9
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Lipopolysaccharide-induced expression of surfactant proteins A1 and A2 in human renal tubular epithelial cells. JOURNAL OF INFLAMMATION-LONDON 2013; 10:2. [PMID: 23311887 PMCID: PMC3691655 DOI: 10.1186/1476-9255-10-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 12/31/2012] [Indexed: 11/10/2022]
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.
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Silveyra P, Floros J. Genetic variant associations of human SP-A and SP-D with acute and chronic lung injury. Front Biosci (Landmark Ed) 2012; 17:407-29. [PMID: 22201752 DOI: 10.2741/3935] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Pulmonary surfactant, a lipoprotein complex, maintains alveolar integrity and plays an important role in lung host defense, and control of inflammation. Altered inflammatory processes and surfactant dysfunction are well described events that occur in patients with acute or chronic lung disease that can develop secondary to a variety of insults. Genetic variants of surfactant proteins, including single nucleotide polymorphisms, haplotypes, and other genetic variations have been associated with acute and chronic lung disease throughout life in several populations and study groups. The hydrophilic surfactant proteins SP-A and SP-D, also known as collectins, in addition to their surfactant-related functions, are important innate immunity molecules as these, among others, exhibit the ability to bind and enhance clearance of a wide range of pathogens and allergens. This review focuses on published association studies of human surfactant proteins A and D genetic polymorphisms with respiratory, and non-respiratory diseases in adults, children, and newborns. The potential role of genetic variations in pulmonary disease or pathogenesis is discussed following an evaluation, and comparison of the available literature.
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Affiliation(s)
- Patricia Silveyra
- Center for Host Defense, Inflammation, and Lung Disease Research, Department of Pediatrics, Pennsylvania State University College of Medicine, Pennsylvania, USA
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11
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Relationship between surfactant protein A polymorphisms and allergic rhinitis in a Chinese Han population. Mol Biol Rep 2010; 38:1475-82. [DOI: 10.1007/s11033-010-0254-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Accepted: 09/02/2010] [Indexed: 12/29/2022]
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12
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Maitra M, Wang Y, Gerard RD, Mendelson CR, Garcia CK. Surfactant protein A2 mutations associated with pulmonary fibrosis lead to protein instability and endoplasmic reticulum stress. J Biol Chem 2010; 285:22103-13. [PMID: 20466729 PMCID: PMC2903395 DOI: 10.1074/jbc.m110.121467] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Revised: 05/11/2010] [Indexed: 12/25/2022] Open
Abstract
Rare heterozygous mutations in the gene encoding surfactant protein A2 (SP-A2, SFTPA2) are associated with adult-onset pulmonary fibrosis and adenocarcinoma of the lung. We have previously shown that two recombinant SP-A2 mutant proteins (G231V and F198S) remain within the endoplasmic reticulum (ER) of A549 cells and are not secreted into the culture medium. The pathogenic mechanism of the mutant proteins is unknown. Here we analyze all common and rare variants of the surfactant protein A2, SP-A2, in both A549 cells and in primary type II alveolar epithelial cells. We show that, in contrast with all other SP-A2 variants, the mutant proteins are not secreted into the medium with wild-type SP-A isoforms, form fewer intracellular dimer and trimer oligomers, are partially insoluble in 0.5% Nonidet P-40 lysates of transfected A549 cells, and demonstrate greater protein instability in chymotrypsin proteolytic digestions. Both the G231V and F198S mutant SP-A2 proteins are destroyed via the ER-association degradation pathway. Expression of the mutant proteins increases the transcription of a BiP-reporter construct, expression of BiP protein, and production of an ER stress-induced XBP-1 spliced product. Human bronchoalveolar wash samples from individuals who are heterozygous for the G231V mutation have similar levels of total SP-A as normal family members, which suggests that the mechanism of disease does not involve an overt lack of secreted SP-A but instead involves an increase in ER stress of resident type II alveolar epithelial cells.
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Affiliation(s)
- Meenakshi Maitra
- From the Eugene McDermott Center for Human Growth and Development and
| | - Yongyu Wang
- From the Eugene McDermott Center for Human Growth and Development and
| | | | - Carole R. Mendelson
- Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390
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van Rozendaal BAWM, van Golde LMG, Haagsman HP. Localization and Functions of SP-A and SP-D at Mucosal Surfaces. ACTA ACUST UNITED AC 2010. [DOI: 10.1080/15513810109168824] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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14
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Khubchandani KR, Goss KL, Engelhardt JF, Snyder JM. In Situ Hybridization of SP-A mRNA in Adult Human Conducting Airways. ACTA ACUST UNITED AC 2010. [DOI: 10.1080/15513810109168620] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Wang G, Guo X, Diangelo S, Thomas NJ, Floros J. Humanized SFTPA1 and SFTPA2 transgenic mice reveal functional divergence of SP-A1 and SP-A2: formation of tubular myelin in vivo requires both gene products. J Biol Chem 2010; 285:11998-2010. [PMID: 20048345 DOI: 10.1074/jbc.m109.046243] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Surfactant protein A (SP-A) plays a role in lung innate immunity and surfactant-related functions. Two functional genes, SP-A1 (SFTPA1) and SP-A2 (SFTPA2), are present in humans and primates (rodents have one gene). Single gene SP-A1 or SP-A2 proteins expressed in vitro are functional. To study their role in vivo, we generated humanized transgenic (hTG) C57BL/6 mice, SP-A1(6A(4)) and SP-A2(1A(3)). The SP-A cDNA in experimental constructs was driven by the 3.7-kb SP-C promoter. Positive hTG mice were bred with SP-A knock-out mice to generate F8 offspring for study. Epithelial alveolar type II cells were SP-A-positive, and Clara cells were negative by immunohistochemistry in hTG mice. The levels of SP-A in lungs of two hTG lines used were comparable with those in human lungs. Southern blot analysis indicated that two cDNA copies of either SP-A1(6A(4)) or SP-A2(1A(3)) were integrated as a concatemer into the genome of each of the two hTG lines. Electron microscopy analysis revealed that hTG mice with a single SP-A1(6A(4)) or SP-A2(1A(3)) gene product lacked tubular myelin (TM), but hTG mice carrying both had TM. Furthermore, TM was observed in human bronchoalveolar lavage fluid only if both SP-A1 and SP-A2 gene products were present and not in those containing primarily (>99.7%) either SP-A1 or SP-A2 gene products. In vivo rescue study confirmed that TM can only be restored after administering exogenous SP-A containing both SP-A1 and SP-A2 into the lungs of SP-A knock-out mice. These observations indicate that SP-A1 and SP-A2 diverged functionally at least in terms of TM formation.
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Affiliation(s)
- Guirong Wang
- Penn State Center for Host Defense, Inflammation, and Lung Disease Research, Department of Pediatrics, Penn State HersheyCollege ofMedicine, Pennsylvania State University, Hershey, Pennsylvania 17033, USA
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Presence and subcellular localizations of surfactant proteins A and D in human spermatozoa. Fertil Steril 2008; 90:1904-9. [PMID: 18191856 DOI: 10.1016/j.fertnstert.2007.09.064] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Revised: 09/24/2007] [Accepted: 09/24/2007] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To investigate the presence of surfactant protein-A (SP-A); molecular weight 34 kDa and surfactant protein-D (SP-D); and molecular weight 43 kDa in human spermatozoa. DESIGN Prospective, research study. SETTING Two universities in Turkey. PATIENT(S) Semen specimens (n = 10) were obtained from normozoospermic donors. INTERVENTION(S) Human sperm were exposed to an anti-human SP-A polyclonal antibody, and monoclonal antibody, to human SP-D protein. MAIN OUTCOME MEASURE(S) Presence of SP-A and SP-D proteins in human beings. RESULT(S) Indirect immunofluorescence assays of human sperm indicated the presence of SP-A in the mid piece, the tail, and sometimes at the equatorial region of spermatozoa. A brilliant green light detected SP-D in the tails and acrosome of some sperm. The anti-SP-A antibody detected a single band corresponding to the molecular weight values of 34 kDa in spermatozoa, whereas no band was observed in the negative control. The anti-SP-D antibody showed the expected band at 43 kDa in spermatozoa. CONCLUSION(S) This is the first report and a novel finding of the presence of surfactant glycoproteins on human spermatozoa.
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Sánchez-Barbero F, Rivas G, Steinhilber W, Casals C. Structural and functional differences among human surfactant proteins SP-A1, SP-A2 and co-expressed SP-A1/SP-A2: role of supratrimeric oligomerization. Biochem J 2007; 406:479-89. [PMID: 17542781 PMCID: PMC2049033 DOI: 10.1042/bj20070275] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
SP-A (surfactant protein A) is a membrane-associated SP that helps to maintain the lung in a sterile and non-inflamed state. Unlike SP-As from other mammalian species, human SP-A consists of two functional gene products: SP-A1 and SP-A2. In all the functions examined, recombinant human SP-A1 invariably exhibits lower biological activity than SP-A2. The objective of the present study was to investigate why SP-A2 possesses greater biological activity than SP-A1 and what advantage accrues to having two polypeptide chains instead of one. We analysed structural and functional characteristics of recombinant baculovirus-derived SP-A1, SP-A2 and co-expressed SP-A1/SP-A2 using a wide array of experimental approaches such as analytical ultracentrifugation, DSC (differential scanning calorimetry) and fluorescence. We found that the extent of supratrimeric assembly is much lower in SP-A1 than SP-A2. However, the resistance to proteolysis is greater for SP-A1 than for SP-A2. Co-expressed SP-A1/SP-A2 had greater thermal stability than SP-A1 and SP-A2 and exhibited properties of each protein. On the one hand, SP-A1/SP-A2, like SP-A2, had a higher degree of oligomerization than SP-A1, and consequently had lower K(d) for binding to bacterial Re-LPS (rough lipopolysaccharide), higher self-association in the presence of calcium and greater capability to aggregate Re-LPS and phospholipids than SP-A1. On the other hand, SP-A1/SP-A2, like SP-A1, was more resistant to trypsin degradation than SP-A2. Finally, the importance of the supratrimeric assembly for SP-A immunomodulatory function is discussed.
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Affiliation(s)
- Fernando Sánchez-Barbero
- *Departamento de Bioquímica y Biología Molecular I and CIBER (Centro Investigación Biomédica en Red) Enfermedades Respiratorias, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Germán Rivas
- †Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Calle Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Wolfram Steinhilber
- ‡Department of Biotechnology, ALTANA Pharma AG, Byk-Gulden-Strasse 2, 78467 Konstanz, Federal Republic of Germany
| | - Cristina Casals
- *Departamento de Bioquímica y Biología Molecular I and CIBER (Centro Investigación Biomédica en Red) Enfermedades Respiratorias, Universidad Complutense de Madrid, 28040 Madrid, Spain
- To whom correspondence should be addressed (email )
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Mikerov AN, White M, Hartshorn K, Wang G, Floros J. Inhibition of hemagglutination activity of influenza A viruses by SP-A1 and SP-A2 variants expressed in CHO cells. Med Microbiol Immunol 2007; 197:9-12. [PMID: 17520282 PMCID: PMC2917902 DOI: 10.1007/s00430-007-0051-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Indexed: 10/23/2022]
Abstract
Surfactant protein A (SP-A) inhibits hemagglutination (HA) activity and infectivity of influenza A viruses (IAV). As we have showed before in different assays, SP-A2 gene products are more active than SP-A1. Here, we hypothesized that SP-A1 and SP-A2 mammalian CHO-cell-expressed proteins also differentially modulate HA inhibition of IAV. We found that both SP-A1 and SP-A2 equally displayed alpha(2,3)-linked sialic acids, and had similar activity against a strain (PR-8) that preferentially binds to alpha(2,3)-linked sialic acids. Based on these findings, we speculate that in human lung SP-A1 and SP-A2 will not be different in their activity against IAV that preferably bind to alpha(2,3)-linked sialic acids (like avian strains).
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Affiliation(s)
- Anatoly N. Mikerov
- Department of Cellular and Molecular Physiology, H166, The Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Mitch White
- Department of Medicine, Section of Hematology/Oncology, Boston University School of Medicine, Boston, MA USA
| | - Kevan Hartshorn
- Department of Medicine, Section of Hematology/Oncology, Boston University School of Medicine, Boston, MA USA
| | - Guirong Wang
- Department of Cellular and Molecular Physiology, H166, The Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Joanna Floros
- Department of Cellular and Molecular Physiology, H166, The Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA. Department of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA. Department of Obstetrics and Gynecology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
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19
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Sorensen GL, Husby S, Holmskov U. Surfactant protein A and surfactant protein D variation in pulmonary disease. Immunobiology 2007; 212:381-416. [PMID: 17544823 DOI: 10.1016/j.imbio.2007.01.003] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2006] [Accepted: 01/02/2007] [Indexed: 12/17/2022]
Abstract
Surfactant proteins A (SP-A) and D (SP-D) have been implicated in pulmonary innate immunity. The proteins are host defense lectins, belonging to the collectin family which also includes mannan-binding lectin (MBL). SP-A and SP-D are pattern-recognition molecules with the lectin domains binding preferentially to sugars on a broad spectrum of pathogen surfaces and thereby facilitating immune functions including viral neutralization, clearance of bacteria, fungi and apoptotic and necrotic cells, modulation of allergic reactions, and resolution of inflammation. SP-A and SP-D can interact with receptor molecules present on immune cells leading to enhanced microbial clearance and modulation of inflammation. SP-A and SP-D also modulate the functions of cells of the adaptive immune system including dendritic cells and T cells. Studies on SP-A and SP-D polymorphisms and protein levels in bronchoalveolar lavage and blood have indicated associations with a multitude of pulmonary inflammatory diseases. In addition, accumulating evidence in mouse models of infection and inflammation indicates that recombinant forms of the surfactant proteins are biologically active in vivo and may have therapeutic potential in controlling pulmonary inflammatory disease. The presence of the surfactant collectins, especially SP-D, in non-pulmonary tissues, such as the gastrointestinal tract and genital organs, suggest additional actions located to other mucosal surfaces. The aim of this review is to summarize studies on genetic polymorphisms, structural variants, and serum levels of human SP-A and SP-D and their associations with human pulmonary disease.
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20
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Oberley RE, George CLS, Snyder JM. A new tool to investigate differences between human SP-A1 and SP-A2. Am J Physiol Lung Cell Mol Physiol 2007; 292:L1050-1. [PMID: 17293378 DOI: 10.1152/ajplung.00039.2007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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21
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Tagaram HRS, Wang G, Umstead TM, Mikerov AN, Thomas NJ, Graff GR, Hess JC, Thomassen MJ, Kavuru MS, Phelps DS, Floros J. Characterization of a human surfactant protein A1 (SP-A1) gene-specific antibody; SP-A1 content variation among individuals of varying age and pulmonary health. Am J Physiol Lung Cell Mol Physiol 2006; 292:L1052-63. [PMID: 17189324 DOI: 10.1152/ajplung.00249.2006] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The human surfactant protein A (SP-A) locus consists of two functional genes (SP-A1, SP-A2) with gene-specific products exhibiting qualitative and quantitative differences. The aim here was twofold: 1) generate SP-A1 gene-specific antibody, and 2) use this to assess gene-specific SP-A content in the bronchoalveolar lavage fluid (BALF). An SP-A1-specific polyclonal antibody (hSP-A1_Ab(68-88)_Col) was raised in chicken, and its specificity was determined by immunoblot and ELISA using mammalian Chinese hamster ovary (CHO) cell-expressed SP-A1 and SP-A2 variants and by immunofluorescence with stably transfected CHO cell lines expressing SP-A1 or SP-A2 variants. SP-A1 content was evaluated according to age and lung status. A gradual decrease (P < 0.05) in SP-A1/SP-A ratio was observed in healthy subjects (HS) with increased age, although no significant change was observed in total SP-A content among age groups. Total SP-A and SP-A1 content differed significantly between alveolar proteinosis (AP) patients and HS, with no significant difference observed in SP-A1/SP-A ratio between AP and HS. The cystic fibrosis (CF) ratio was significantly higher compared with AP, HS, and noncystic fibrosis (NCF), even though SP-A1 and total SP-A were decreased in CF compared with most of the other groups. The ratio was higher in culture-positive vs. culture-negative samples from CF and NCF (P = 0.031). A trend of an increased ratio was observed in culture-positive CF (0.590 +/- 0.10) compared with culture-positive NCF (0.368 +/- 0.085). In summary, we developed and characterized an SP-A1 gene-specific antibody and used it to identify gene-specific SP-A content in BALFs as a function of age and lung health.
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Affiliation(s)
- Hephzibah Rani S Tagaram
- Departments of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
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22
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Woodworth BA, Lathers D, Neal JG, Skinner M, Richardson M, Young MR, Schlosser RJ. Immunolocalization of surfactant protein A and D in sinonasal mucosa. ACTA ACUST UNITED AC 2006; 20:461-5. [PMID: 16955780 DOI: 10.2500/ajr.2006.20.2892] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Surfactant-associated proteins (SP) A and D are in the family of collectin proteins that play an integral part in the innate defense system. SP-A and SP-D expression and function are altered in a variety of inflammatory and infectious diseases of the lungs, such as asthma, allergies, and cystic fibrosis. Our prior studies are the first to identify the presence of these proteins in the human sinonasal cavity. The objective of this study was to immunolocalize SP-A and SP-D in human sinonasal tissue. METHODS Sinonasal mucosal biopsies were performed in patients with various forms of chronic hyperplastic rhinosinusitis with nasal polyposis and nondiseased mucosa from patients undergoing transsphenoidal hypophysectomy. (n = 10) Immunolocalization of surfactant proteins was performed with antibodies to SP-A and SP-D using immunoperoxidase staining technique. Isotype-negative controls were performed on all specimens. RESULTS Analyses of mucosal biopsy specimens from human sinonasal tissue reveals staining within respiratory and intermediate (metaplastic)-type surface epithelium. In addition, staining was intense in the submucosal ductal epithelium of the seromucinous glands. These properties appear to be consistent regardless of disease state and location within the sinuses. CONCLUSION This is the first study to immunolocalize SP-A and SP-D in sinonasal human mucosa. These are secreted proteins that are intricately involved in innate immunity in the lungs. Their secretion in the upper airway indicates that future studies may allow manipulation of these proteins and development of novel treatments for sinonasal pathology.
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Affiliation(s)
- Bradford A Woodworth
- Department of Otolaryngology-Head and Neck Surgery, Medical University of South, Charleston 29425, USA.
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23
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Kankavi O, Ata A, Gungor O. Surfactant proteins A and D in the genital tract of mares. Anim Reprod Sci 2006; 98:259-70. [PMID: 16621351 DOI: 10.1016/j.anireprosci.2006.03.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2005] [Revised: 01/26/2006] [Accepted: 03/13/2006] [Indexed: 11/18/2022]
Abstract
The presence of surface-active material in the lung alveolus has been known for several decades as being essential for normal lung function. Surfactant is essential for reducing the surface tension at the alveolar air-liquid interface. Pulmonary surfactant is composed of 90% lipids and 10% proteins. There are four non-serum proteins surfactant protein-A (SP-A), surfactant protein-B (SP-B), surfactant protein-C (SP-C) and surfactant protein-D (SP-D) named in chronologic order of discovery. Lung SP-A and SP-D belong to a family of collagen-containing C-type lectin family called collectins. The host defence and controlling inflammatory processes of the lung are the major functions of SP-A and SP-D. SP-A and SP-D were originally demonstrated in alveolar type II cells, but recent studies have shown extrapulmonary expression of SP-A and SP-D indicating systemic roles of these proteins. Present study describes the presence of SP-A and SP-D in the mare genital tract, vulva, vagina, ovarium, uterus and tuba uterina using immunohistochemistry and Western blotting. The aim of this study was to characterize surfactant proteins in terms of: (i) whether surfactant proteins were present in the various structures of the mare genital system, (ii) if so, identifying and locating the surfactant proteins and finally (iii) determining the differences from those previously characterized for the lung. Although beyond the scope of this report, it is recognized that there are also some potential implications for better defining the reproductive defence mechanisms in mare. Therefore, genital system organs and tissues from mares were examined. We were able to show that proteins reactive with surfactant-specific antibodies were present in the mare genital tract. Thus, surfactant proteins are present not in just lamellar bodies associated with lung, but also genital system of mare.
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Affiliation(s)
- Orhan Kankavi
- Department of Biochemistry, Burdur Faculty of Veterinary Medicine, The University of Akdeniz, 15100 Burdur, Turkey.
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24
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Lee HM, Kang HJ, Woo JS, Chae SW, Lee SH, Hwang SJ. Upregulation of Surfactant Protein A in Chronic Rhinosinusitis. Laryngoscope 2006; 116:328-30. [PMID: 16467728 DOI: 10.1097/01.mlg.0000194223.22763.5f] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Surfactant protein A (SP-A) is protein that appears to play an important role in mammalian first-line host defense. However, the presence of SP-A in the human paranasal sinus mucosa is not well known. The purpose of this study was to investigate the expression of SP-A protein in human paranasal sinus mucosa and to compare the expression of SP-A mRNA between normal paranasal sinus mucosa and paranasal sinus mucosa with chronic rhinosinusitis. METHODS Paranasal sinus mucosa samples from 10 patients who underwent surgery for chronic rhinosinusitis without polyps and 10 normal control subjects were used. Reverse transcriptase polymerase chain reaction was done to detect SP-A mRNA. The expression level of SP-A transcripts was semiquantified with desitometry. Cellular localization of SP-A was sought by using immunohistochemistry. RESULTS SP-A mRNA and protein were expressed in the human paranasal sinus mucosa. SP-A/GAPDH mRNA ratio in the paranasal sinus mucosa with chronic rhinosinusitis was greater compared with that in normal paranasal sinus mucosa (P<.05). Immunohistochemical staining revealed SP-A immunoreactivity in the epithelial cells and submucosal glands of paranasal sinus mucosa in both control subjects and chronic sinusitis patients. Stronger immunoreactivity was observed in chronic rhinosinusitis mucosa as compared with normal paranasal sinus mucosa. CONCLUSION SP-A mRNA and protein are present in both normal and diseased human paranasal sinus mucosa. These results may provide potential targets for novel therapy of chronic rhinosinusitis.
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Affiliation(s)
- Heung-Man Lee
- Division of Brain Korea 21 Program for Biomedical Science, Korea University College of Medicine, Seoul, Korea.
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25
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Seifart C, Lin HM, Seifart U, Plagens A, DiAngelo S, von Wichert P, Floros J. Rare SP-A alleles and the SP-A1-6A4 allele associate with risk for lung carcinoma. Clin Genet 2005; 68:128-36. [PMID: 15996209 DOI: 10.1111/j.1399-0004.2005.00470.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Next to cigarette smoking, genetic factors may contribute to lung cancer risk. Pulmonary surfactant components may mediate response to inhaled carcinogenic substances and/or play a role in lung function and inflammation. We studied associations between surfactant protein (SP) genetic variants and risk in lung cancer subgroups. Samples (n=308) were genotyped for SP-A1, -A2, -B, and -D marker alleles. These included 99 patients with small cell lung carcinoma (SCLC, n=31), or non-SCLC (NSCLC, n=68) consisting of squamous cell carcinoma (SCC, n=35), and adenocarcinoma (AC) (n=23); controls (n=99) matched by age, sex, and smoking status (clinical control) to SCLC and NSCLC; and 110 healthy individuals (population control). We found (a) no significant marker associations with SCLC, (b) rare SP-A2 (1A9) and SP-A1 (6A11) alleles associate with NSCLC risk when compared with population control, (c) the same alleles (1A9, 6A11) associate with risk for AC when compared with population (6A11) or clinical control (1A9), and (d) the SP-A1-6A4 allele (found in approximately 10% of the population) associates with SCC, when compared with population or clinical control. A correlation between SP-A variants and lung cancer susceptibility appears to exist, indicating that SP-A alleles may be useful markers of lung cancer risk.
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Affiliation(s)
- C Seifart
- Department of Internal Medicine, Division of Respiratory Medicine, Philipps-University of Marburg, Marburg, Germany.
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Edwards JA, Groathouse NA, Boitano S. Bordetella bronchiseptica adherence to cilia is mediated by multiple adhesin factors and blocked by surfactant protein A. Infect Immun 2005; 73:3618-26. [PMID: 15908391 PMCID: PMC1111863 DOI: 10.1128/iai.73.6.3618-3626.2005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the virulent state (Bvg+), Bordetella bronchiseptica expresses adhesins and toxins that mediate adherence to the upper airway epithelium, an essential early step in pathogenesis. In this study, we used a rabbit tracheal epithelial cell binding assay to test how specific host or pathogen factors contribute to ciliary binding. The host antimicrobial agent surfactant protein A (SP-A) effectively reduced ciliary binding by Bvg+ B. bronchiseptica. To evaluate the relative contributions of bacterial adhesins and toxins to ciliary binding, we used mutant strains of B. bronchiseptica in the binding assay. When compared to Bvg+ or Bvg- phase-locked B. bronchiseptica strains, single-knockout strains lacking one of the known adhesins (filamentous hemagglutinin, pertactin, or fimbriae) displayed an intermediate ciliary binding capacity throughout the coincubation. A B. bronchiseptica strain deficient in adenylate cyclase-hemolysin toxin also displayed an intermediate level of adherence between Bvg+ and Bvg- strains and had the lowest ciliary affinity of any of the Bvg+ phase strains tested. A B. bronchiseptica strain that was missing dermonecrotic toxin also displayed intermediate binding; however, this strain displayed ciliary binding significantly higher than most of the adhesin knockouts tested. Taken together, these findings suggest that virulent-state B. bronchiseptica expresses multiple adhesins with overlapping contributions to ciliary adhesion and that host production of SP-A can provide innate immunity by blocking bacterial adherence to the ciliated epithelium.
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Affiliation(s)
- Jessica A Edwards
- Arizona Respiratory Center, Room 2338, AHSC Arizona Health Sciences Center, 1501 N. Campbell Avenue, Tucson, AZ 85724-5030, USA
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27
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Casals C, García-Verdugo I. Molecular and Functional Properties of Surfactant Protein A. LUNG BIOLOGY IN HEALTH AND DISEASE 2005. [DOI: 10.1201/b14169-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Wang G, Guo X, Floros J. Differences in the translation efficiency and mRNA stability mediated by 5'-UTR splice variants of human SP-A1 and SP-A2 genes. Am J Physiol Lung Cell Mol Physiol 2005; 289:L497-508. [PMID: 15894557 DOI: 10.1152/ajplung.00100.2005] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Surfactant protein A (SP-A) plays an important role in host defense, modulation of inflammatory processes, and surfactant-related functions of the lung. The human SP-A (hSP-A) locus consists of two functional genes, SP-A1 and SP-A2. Several hSP-A 5'-untranslated region (UTR) splice variants for each gene have been characterized and shown to be translated in vitro and in vivo. In this report, we investigated the role of hSP-A 5'-UTR splice variants on SP-A production and molecular mechanisms involved. We used in vitro transient expression of hSP-A 5'-UTR constructs containing luciferase as the reporter gene and quantitative real-time PCR to study hSP-A 5'-UTR-mediated gene expression. We found that 1) the four (A'D', ABD, AB'D', and A'CD') 5'-UTR splice variants under study enhanced gene expression, by increasing luciferase activity from 2.5- to 19.5-fold and luciferase mRNA from 4.3- to 8.8-fold compared with the control vector that lacked hSP-A 5'-UTR; 2) all four 5'-UTR splice variants studied regulated mRNA stability. The ABD variant exhibited the lowest rate of mRNA decay compared with the other three constructs (A'D', AB'D', and A'CD'). These three constructs also exhibited significantly lower rate of mRNA decay compared with the control vector; 3) based on the indexes of translational efficiency (luciferase activity/mRNA), ABD and AB'D' exhibited higher translational efficiency compared with the control vector, whereas the translational efficiency of each A'D' and A'CD' was lower than that of the control vector. These findings indicate that the hSP-A 5'-UTR splice variants play an important role in both SP-A translation and mRNA stability.
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Affiliation(s)
- Guirong Wang
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, 17033, USA
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Janic B, Umstead TM, Phelps DS, Floros J. Modulatory effects of ozone on THP-1 cells in response to SP-A stimulation. Am J Physiol Lung Cell Mol Physiol 2004; 288:L317-25. [PMID: 15466251 DOI: 10.1152/ajplung.00125.2004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Ozone (O(3)), a major component of air pollution and a strong oxidizing agent, can lead to lung injury associated with edema, inflammation, and epithelial cell damage. The effects of O(3) on pulmonary immune cells have been studied in various in vivo and in vitro systems. We have shown previously that O(3) exposure of surfactant protein (SP)-A decreases its ability to modulate proinflammatory cytokine production by cells of monocyte/macrophage lineage (THP-1 cells). In this report, we exposed THP-1 cells and/or native SP-A obtained from bronchoalveolar lavage of patients with alveolar proteinosis to O(3) and studied cytokine production and NF-kappaB signaling. The results showed 1) exposure of THP-1 cells to O(3) significantly decreased their ability to express TNF-alpha in response to SP-A; TNF-alpha production, under these conditions, was still significantly higher than basal (unstimulated) levels in filtered air-exposed THP-1 cells; 2) exposure of both THP-1 cells and SP-A to O(3) did not result in any significant differences in TNF-alpha expression compared with basal levels; 3) O(3) exposure of SP-A resulted in a decreased ability of SP-A to activate the NF-kappaB pathway, as assessed by the lack of significant increase and decrease of the nuclear p65 subunit of NF-kappaB and cytoplasmic IkappaBalpha, respectively; and 4) O(3) exposure of THP-1 cells resulted in a decrease in SP-A-mediated THP-1 cell responsiveness, which did not seem to be mediated via the classic NF-kappaB pathway. These findings indicate that O(3) exposure may mediate its effect on macrophage function both directly and indirectly (via SP-A oxidation) and by involving different mechanisms.
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Affiliation(s)
- Branislava Janic
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
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Madsen J, Tornoe I, Nielsen O, Koch C, Steinhilber W, Holmskov U. Expression and localization of lung surfactant protein A in human tissues. Am J Respir Cell Mol Biol 2003; 29:591-7. [PMID: 12777246 DOI: 10.1165/rcmb.2002-0274oc] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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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Affiliation(s)
- Jens Madsen
- Department of Immunology and Microbiology, Institute of Medical Biology, University of Southern Denmark, Winsløwparken 21.1, DK-5000 Odense C, Denmark
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Oberley RE, Snyder JM. Recombinant human SP-A1 and SP-A2 proteins have different carbohydrate-binding characteristics. Am J Physiol Lung Cell Mol Physiol 2003; 284:L871-81. [PMID: 12505869 DOI: 10.1152/ajplung.00241.2002] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Surfactant protein (SP)-A is a member of the collectin family of proteins and plays a role in innate host defense of the lung. SP-A binds to the carbohydrates of lung pathogens via its calcium-dependant carbohydrate-binding domain. Native human alveolar SP-A consists of two distinct gene products: SP-A1 and SP-A2; however, only SP-A2 is expressed in the submucosal glands of the conducting airways. The function of the isolated SP-A2 protein is unknown. We hypothesized that SP-A1 and SP-A2 might have different carbohydrate-binding properties. In this study, we characterized the carbohydrate-binding specificities of native human alveolar SP-A and recombinant human SP-A1 and SP-A2 in the presence of either 1 or 5 mM Ca(2+). We found that all of the SP-A proteins bind carbohydrates but with different affinities. All of the SP-A proteins bind to fucose with the greatest affinity. SP-A2 binds with a higher affinity to a wider variety of sugars than SP-A1 at either 1 or 5 mM Ca(2+). These findings are suggestive that SP-A2 may interact with a greater variety of pathogens than native SP-A.
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Affiliation(s)
- Rebecca E Oberley
- Department of Anatomy and Cell Biology, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA
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García-Verdugo I, Wang G, Floros J, Casals C. Structural analysis and lipid-binding properties of recombinant human surfactant protein a derived from one or both genes. Biochemistry 2002; 41:14041-53. [PMID: 12437362 DOI: 10.1021/bi026540l] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Surfactant protein A (SP-A) constitutes an important part of the innate immune defense in the lung. In humans there are two functional genes (SP-A1 and SP-A2). The functional importance of having two distinct chain types in human SP-A is undefined. Amino acid substitutions in the primary structure of the protein may have effects on structural stability or on activity. To address this issue, SP-A1, SP-A2, and coexpressed SP-A1/SP-A2 variants were in vitro expressed in insect cells, purified, and used for study. We found the following: (1) Human SP-A variants expressed in insect cells, derived from one gene (SP-A1 or SP-A2) or both genes, differ in the relative extent and heterogeneity of oligomerization. SP-A1 and SP-A2 exist in small oligomeric forms, whereas coexpressed SP-A1/SP-A2 products favor the formation of larger oligomers. (2) Circular dichroic and fluorescence spectroscopic studies identified structural differences between SP-A variants in the collagen domain, with SP-A2 being more stable than SP-A1 but not in the calcium binding region. Recombinant human SP-A variants expressed in insect cells exhibit a lower melting temperature compared to native human SP-A. Oligomerization does not increase the thermal stability of the collagen domain of coexpressed SP-A1/SP-A2. (3) The ability of SP-A to undergo self-aggregation and induce phospholipid and bacterial lipopolysaccharide aggregation is greater for SP-A2 than for coexpressed SP-A1/SP-A2, which in turn is greater than that observed for SP-A1. The presence of SP-A1 polypeptide chains in coexpressed products modulates functional capabilities of SP-A, which depend on both the collagen and globular domains.
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Affiliation(s)
- I García-Verdugo
- Department of Biochemistry and Molecular Biology I, Complutense University of Madrid, 28040-Madrid, Spain
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Abstract
The lung collectins, SP-A and SP-D, are important components of the innate immune response to microbial challenge and participate in other aspects of immune and inflammatory regulation within the lung. Both proteins bind to surface structures expressed by a wide variety of microorganisms and have the capacity to modulate multiple leukocyte functions, including the enhanced internalization and killing of certain microorganisms in vitro. In addition, transgenic mice with deficiencies in SP-A and SP-D show defective or altered responses to challenge with bacterial, fungal, and viral microorganisms and to bacterial lipopolysaccharides in vivo. Thus collectins could play particularly important roles in settings of inadequate or impaired specific immunity, and acquired alterations in the levels of active collectins within the airspaces and distal airways may increase susceptibility to infection.
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Affiliation(s)
- E Crouch
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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Palaniyar N, Ikegami M, Korfhagen T, Whitsett J, McCormack FX. Domains of surfactant protein A that affect protein oligomerization, lipid structure and surface tension. Comp Biochem Physiol A Mol Integr Physiol 2001; 129:109-27. [PMID: 11369537 DOI: 10.1016/s1095-6433(01)00309-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Surfactant protein A (SP-A) is an abundant protein found in pulmonary surfactant which has been reported to have multiple functions. In this review, we focus on the structural importance of each domain of SP-A in the functions of protein oligomerization, the structural organization of lipids and the surface-active properties of surfactant, with an emphasis on ultrastructural analyses. The N-terminal domain of SP-A is required for disulfide-dependent protein oligomerization, and for binding and aggregation of phospholipids, but there is no evidence that this domain directly interacts with lipid membranes. The collagen-like domain is important for the stability and oligomerization of SP-A. It also contributes shape and dimension to the molecule, and appears to determine membrane spacing in lipid aggregates such as common myelin and tubular myelin. The neck domain of SP-A is primarily involved in protein trimerization, which is critical for many protein functions, but it does not appear to be directly involved in lipid interactions. The globular C-terminal domain of SP-A clearly plays a central role in lipid binding, and in more complex functions such as the formation and/or stabilization of curved membranes. In recent work, we have determined that the maintenance of low surface tension of surfactant in the presence of serum protein inhibitors requires cooperative interactions between the C-terminal and N-terminal domains of the molecule. This effect of SP-A requires a high degree of oligomeric assembly of the protein, and may be mediated by the activity of the protein to alter the form or physical state of surfactant lipid aggregates.
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Affiliation(s)
- N Palaniyar
- MRC Immunochemistry Unit, Department of Biochemistry, University of Oxford, South Parks Road, OX1 3QU, Oxford, UK.
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35
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Ferguson JS, Schlesinger LS. Pulmonary surfactant in innate immunity and the pathogenesis of tuberculosis. TUBERCLE AND LUNG DISEASE : THE OFFICIAL JOURNAL OF THE INTERNATIONAL UNION AGAINST TUBERCULOSIS AND LUNG DISEASE 2001; 80:173-84. [PMID: 11052906 DOI: 10.1054/tuld.2000.0242] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Components of the innate immune system serve to protect the host from invading pathogens prior to the generation of a directed immune response, and influence the manner in which the directed immune response develops. The pulmonary surfactant system consists of a complex array of proteins and lipids that reduce surface tension of the alveoli, and appears to play an essential role in innate immunity. Investigators have recently gained insight into the interactions between components of the surfactant system and the respiratory pathogen Mycobacterium tuberculosis. It is likely that pulmonary surfactant and other innate immune determinants play significant roles in the pathogenesis of tuberculosis.
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Affiliation(s)
- J S Ferguson
- Department of Internal Medicine, Iowa City Veterans Affairs Medical Center and the University of Iowa, Iowa City, IA, 52242, USA.
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Awasthi S, Coalson JJ, Yoder BA, Crouch E, King RJ. Deficiencies in lung surfactant proteins A and D are associated with lung infection in very premature neonatal baboons. Am J Respir Crit Care Med 2001; 163:389-97. [PMID: 11179112 DOI: 10.1164/ajrccm.163.2.2004168] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Surfactant proteins A (SP-A) and D (SP-D) are important in the innate host defense against pathogenic microorganisms. A deficit in these proteins in premature infants, either because of immaturity or as a consequence of superimposed chronic lung disease (CLD), could increase their susceptibility to infection. The study reported here examined infection in CLD in the premature newborn baboon, and correlated it with the amounts of SP-A and SP-D in lung tissue and lavage fluid. Two groups of baboons were delivered prematurely, at 125 d gestational age (g.a.), and differed principally in whether they developed naturally acquired pulmonary infections and sepsis. Group I animals were ventilated with clinically appropriate oxygen for 6 d and 14 d without clinical incident. Group II animals were ventilated for 5 to 71 d, but differed from those in Group I in that most developed pulmonary infection and/or sepsis. In Group I animals, tissue pools of both SP-A and SP-D were equal to or exceeded those in adults, and lavage pools of SP-A increased progressively with the time of ventilation to about 35% of adult levels after 14 d. In contrast, most Group II animals had concentrations of lavage SP-A that were less than 20% of that in adult animals. A low concentration of lavage SP-A correlated with the release of interleukin-8, and with a high "infection index" based on histopathology, microbiologic cultures, and clinical indications of sepsis. Our data suggest that the amounts of SP-A and SP-D in lavage fluid are indicators of the risk of infection in the evolution of neonatal CLD. Deficits in the amount of lavage SP-A, even after 60 d of ventilation, may have inhibited the resolution of infection and thereby contributed to the developing injury among our Group II animals.
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Affiliation(s)
- S Awasthi
- Department of Physiology, University of Texas Health Science Center, and Southwest Foundation for Biomedical Research, San Antonio, Texas 78229-3900, USA
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37
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Saitoh H, Masuda T, Shimura S, Fushimi T, Shirato K. Secretion and gene expression of secretory leukocyte protease inhibitor by human airway submucosal glands. Am J Physiol Lung Cell Mol Physiol 2001; 280:L79-87. [PMID: 11133497 DOI: 10.1152/ajplung.2001.280.1.l79] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Submucosal glands were isolated within 4 h of death from tracheae and bronchi obtained from autopsied lungs, and the secretory response of secretory leukocyte protease inhibitor (SLPI) was examined with ELISA and a secretory index. Although human neutrophil elastase (HNE) at low concentrations increased SLPI secretion above the control level (i.e., 149% of control level at 10(-11) M), HNE at high concentrations significantly decreased it below the control level (i.e., 16% of control level at 10(-7) M). The decrease in SLPI concentration was shown to result from the degradation of SLPI by excessive HNE. Methacholine induced significant secretion (i.e., 363% of control level at 10(-5) M) that was abolished by both M(1) and M(3) receptor antagonists. A semiquantitative analysis of SLPI mRNA by RT-PCR and Southern blot showed that compared with the superficial epithelium, submucosal glands had a 30-fold or higher level of SLPI mRNA. Both HNE and methacholine significantly increased the level of SLPI mRNA in submucosal glands in a dose-dependent manner (i.e., 357% of control level at 10(-7) M and 175% of control level at 10(-5) M, respectively). These findings indicate that human airway submucosal glands can transcribe 30-fold or more SLPI mRNA than the superficial epithelium and that SLPI mRNA transcription and secretion are regulated by both HNE and muscarinic receptors.
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Affiliation(s)
- H Saitoh
- First Department of Internal Medicine, Tohoku University School of Medicine, Sendai 980-8574, Japan
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38
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Abstract
Surfactant protein A (SP-A) is the major protein component of pulmonary surfactant, a material secreted by the alveolar type II cell that reduces surface tension at the alveolar air-liquid interface. The function of SP-A in the alveolus is to facilitate the surface tension-lowering properties of surfactant phospholipids, regulate surfactant phospholipid synthesis, secretion, and recycling, and counteract the inhibitory effects of plasma proteins released during lung injury on surfactant function. It has also been shown that SP-A modulates host response to microbes and particulates at the level of the alveolus. More recently, several investigators have reported that pulmonary surfactant phospholipids and SP-A are present in nonalveolar pulmonary sites as well as in other organs of the body. We describe the structure and possible functions of alveolar SP-A as well as the sites of extra-alveolar SP-A expression and the possible functions of SP-A in these sites.
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Affiliation(s)
- K R Khubchandani
- Department of Anatomy and Cell Biology, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA
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39
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Wang G, Phelps DS, Umstead TM, Floros J. Human SP-A protein variants derived from one or both genes stimulate TNF-alpha production in the THP-1 cell line. Am J Physiol Lung Cell Mol Physiol 2000; 278:L946-54. [PMID: 10781424 DOI: 10.1152/ajplung.2000.278.5.l946] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In humans, two functional genes of surfactant protein (SP) A, SP-A1 and SP-A2, and several alleles of each functional gene have been characterized. SP-A is a multimeric molecule consisting of six trimers. Each trimer contains two SP-A1 molecules and one SP-A2 molecule. Until now, it has been unclear whether a single SP-A gene product is functional or whether there are functional differences either among alleles or between single-gene SP-A products and SP-A products derived from both genes. We tested the ability of in vitro expressed SP-A variants to stimulate tumor necrosis factor (TNF)-alpha production by THP-1 cells. We observed that 1) single-gene products and products derived from both genes stimulate TNF-alpha production, 2) there are differences among SP-A1 and SP-A2 alleles in their ability to stimulate TNF-alpha production, and 3) the increases in TNF-alpha production are lower after treatment with the SP-A1 alleles than after treatment with the SP-A2 alleles. Furthermore, coexpressed SP-As from SP-A1 and SP-A2 genes have a higher activity compared with SP-As from individual alleles or mixed SP-As from SP-A1 and SP-A2 genes. These data suggest that the SP-A-induced increases in TNF-alpha levels differ among SP-A variants and appear to be affected by SP-A genotype and whether SP-A is derived from one or both genes.
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Affiliation(s)
- G Wang
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
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40
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Abstract
Bronchial glands, which consist of mucous and serous cells, are abundant in human airways, playing a major role in the airway secretion. Cl(-) secretion is accompanied by water transport to the lumen in the acinar cells of bronchial glands. Agonists that increase [Ca(2+)]i induce the Cl(-) secretion in bronchial glands. Ca(2+) release from a IP(3)-sensitive Ca(2+) pool at the apical portion stimulates and opens Ca(2+)-sensitive Cl(-) channels at the apical membrane, producing Cl(-) secretion in bronchial glands. K(+) channels at the basolateral membranes are Ca(2+)-sensitive and activated by Ca(2+) release from a cADPribose-sensitive Ca(2+) pool, maintaining the Cl(-) secretion in bronchial glands. Further, cADP ribose in concert with IP(3) induce [Ca(2+)]i oscillation, inducing Cl(-) secretion in bronchial glands. Some tyrosine kinases are involved in the Cl(-) secretion in bronchial glands. Mucous and serous cells in bronchial glands take part in mucin secretion and the secretion of defensive substances (glycoconjugates), respectively. [Ca(2+)]i oscillations are shown to play a central role in the exocytosis of secretory granules in serous cells of bronchial glands. Other signal transductions of mucin and glycoconjugates in airway gland cells remain to be studied, although agonists which increase [cAMP]i are also well known to induce mucin and glycoconjugate secretion from airway glands.
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Affiliation(s)
- S Shimura
- First Department of Internal Medicine, Tohoku University School of Medicine, Seiryo-machi, Aoba-ku, 980-8574, Sendai, Japan.
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Dutton JM, Goss K, Khubchandani KR, Shah CD, Smith RJ, Snyder JM. Surfactant protein A in rabbit sinus and middle ear mucosa. Ann Otol Rhinol Laryngol 1999; 108:915-24. [PMID: 10526845 DOI: 10.1177/000348949910801001] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In the present study, pulmonary surfactant protein A (SP-A) messenger RNA (mRNA) and protein were characterized in adult rabbit middle ear and maxillary sinus. Fifteen adult rabbits were used for the study: 6 with evidence of acute middle ear infections and maxillary sinusitis, 6 with infections that were successfully treated with tetracycline, and 3 that were pathogen-free. We detected SP-A mRNA in maxillary sinus and middle ear tissues by Northern blot analysis and reverse transcriptase-polymerase chain reaction (RT-PCR). The RT-PCR also revealed the presence of SP-B and SP-C mRNA in middle ear and sinus tissues. We detected SP-A protein, of molecular weight approximately 29 and 70 kd, in middle ear and sinus tissues by immunoblot analysis. Unlike the SP-A protein present in the lung, the molecular weight of the SP-A protein present in the middle ear and paranasal sinus was not altered by digestion with an enzyme that cleaves N-linked carbohydrates. Immunostaining and in situ hybridization showed that SP-A protein and mRNA, respectively, were present in surface epithelial cells of the middle ear and in epithelial cells of submucosal glands in sinus tissues. These data provide the first evidence of the presence of pulmonary surfactant proteins in the paranasal sinuses and confirm previous reports of SP-A in the middle ear epithelium.
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Affiliation(s)
- J M Dutton
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, USA
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Rosenberg E, Li F, Smith CI, Reisher SR, Feinstein SI. Transcriptional activation and protein binding by two regions of the rat surfactant protein A promoter. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:L134-41. [PMID: 10409240 DOI: 10.1152/ajplung.1999.277.1.l134] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
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 approximately 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 approximately 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 approximately 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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Affiliation(s)
- E Rosenberg
- Institute for Environmental Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 9104-6068, USA
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