OBJECTIVE: Recent studies have overturned the traditional concept of the lung as a "sterile organ" revealing that pulmonary microbiota dysbiosis and abnormal surfactant proteins (SPs) expression are involved in the progression of silicosis. This study aimed to investigate the relationship between abnormal SPs expression and dysbiosis of lung microbiota in silica-induced lung fibrosis, providing insights into mechanisms of silicosis. METHODS: Lung pathology, SPs expression, and microbiota composition were evaluated in silica-exposed mice. A mouse model of antibiotic-induced microbiota depletion was established, and alveolar structure and SPs expression were assessed. The roles of the lung microbiota and SPs in silicosis progression were further evaluated in mice with antibiotic-induced microbiota depletion, both with and without silica exposure. RESULTS: Silica exposure induced lung inflammation and fibrosis, along with increased expression of SP-A expression. Antibiotics (Abx)-induced microbiota depletion elevated SP-A and SP-D expression. Furthermore, silica exposure altered lung microbiota composition, enriching potentially pathogenic taxa. However, antibiotic-induced microbiota depletion prior to silica exposure reduced silica-mediated lung fibrosis and inflammation. CONCLUSION Lung microbiota is associated with silica-induced lung injury. Overproduction of SP-A and SP-D, induced by Abx-induced microbiota depletion, may enhance the resistance of mouse lung tissue to silica-induced injury.
Animals ; Silicosis/prevention & control* ; Lung/metabolism* ; Mice ; Anti-Bacterial Agents/pharmacology* ; Microbiota/drug effects* ; Silicon Dioxide/toxicity* ; Mice, Inbred C57BL ; Male ; Pulmonary Surfactant-Associated Proteins/genetics*

Pulmonary surfactant (PS) is synthesized and secreted by alveolar epithelial type II (AEII) cells, which is a complex compound formed by proteins and lipids. Surfactant participates in a range of physiological processes such as reducing the surface tension, keeping the balance of alveolar fluid, maintaining normal alveolar morphology and conducting host defense. Genetic disorders of the surfactant homeostasis genes may result in lack of surfactant or cytotoxicity, and lead to multiple lung diseases in neonates, children and adults, including neonatal respiratory distress syndrome, interstitial pneumonia, pulmonary alveolar proteinosis, and pulmonary fibrosis. This paper has provided a review for the functions and processes of pulmonary surfactant metabolism, as well as the connection between disorders of surfactant homeostasis genes and lung diseases.
ATP-Binding Cassette Transporters ; genetics ; DNA-Binding Proteins ; genetics ; Homeostasis ; Humans ; Lung Diseases ; genetics ; Pulmonary Surfactant-Associated Protein C ; genetics ; Pulmonary Surfactants ; metabolism ; Transcription Factors

ATP-Binding Cassette Transporters ; genetics ; metabolism ; Animals ; Biological Transport ; Child ; DNA Mutational Analysis ; Humans ; Hypertension, Pulmonary ; genetics ; metabolism ; Lung Diseases, Interstitial ; genetics ; metabolism ; Molecular Sequence Data ; Mutation ; Polymerase Chain Reaction ; Protein Conformation ; Pulmonary Surfactant-Associated Proteins ; genetics ; metabolism ; Respiratory Distress Syndrome, Newborn ; genetics ; metabolism

OBJECTIVETo explore the prevalence of pulmonary surfactant associated pathway genes functional variants in Chinese population.

METHODUsing a cohort of 258 mixed ethnic population of Han and Zhuang, we pooled DNA samples from 146 term male infants and 112 term female infants and then used an Ill umina next generation sequencing platform to perform the complete exonic resequencing in 6 target genes:surfactant protein-B (SFTPB), surfactant protein-C (SFTPC), ATP-binding cassette transporter A3 (ABCA3), lysophospholipid acyltransferase 1 (LPCAT1), choline phosphotransferase 1 (CHPT1), phosphate cytidylyltransferase 1, choline, beta (PCYT1B). Collapsing methods was used to determine the functional allele frequency.

RESULT(1) Altogether, 128 variants were found, including 44 synonymous variants, 66 nonsynonymous variants and 18 insertions-deletions. Of these, 28 variants were predicted to alter protein function. Two of these variants were seen twice, the rest variants were only seen once, for a total of 30 functional alleles; (2) ABCA3 had the most functional variants in both male and female groups with the minor allele frequencies of 0.014 (1.4%) and 0.04 (4%), respectively. The total functional allele frequencies of 6 genes were 0.041 (4.1%) and 0.08 (8%) in the two groups, respectively (P = 0.06).

CONCLUSION(1) Functional variants in pulmonary surfactant associated pathway genes are present in the mixed Han-Zhuang population. (2) ABCA3 contained the most functional variants suggesting that ABCA3 could contribute significantly to neonatal respiratory distress syndrome and other lung disease.

1-Acylglycerophosphocholine O-Acyltransferase ; genetics ; metabolism ; ATP-Binding Cassette Transporters ; genetics ; Asian Continental Ancestry Group ; ethnology ; genetics ; China ; ethnology ; Female ; Gene Frequency ; Genetic Association Studies ; Genetic Predisposition to Disease ; Genetic Variation ; Genotype ; Humans ; Infant, Newborn ; Male ; Pulmonary Surfactant-Associated Protein C ; genetics ; Pulmonary Surfactant-Associated Proteins ; genetics ; Respiratory Distress Syndrome, Newborn ; ethnology ; genetics

Dendritic-cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN; CD209) has an important role in mediating adherence of Mycobacteria species, including M. tuberculosis and M. bovis BCG to human dendritic cells and macrophages, in which these bacteria can survive intracellularly. DC-SIGN is a C-type lectin, and interactions with mycobacterial cells are believed to occur via mannosylated structures on the mycobacterial surface. Recent studies suggest more varied modes of binding to multiple mycobacterial ligands. Here we identify, by affinity chromatography and mass-spectrometry, four novel ligands of M. bovis BCG that bind to DC-SIGN. The novel ligands are chaperone protein DnaK, 60 kDa chaperonin-1 (Cpn60.1), glyceraldehyde-3 phosphate dehydrogenase (GAPDH) and lipoprotein lprG. Other published work strongly suggests that these are on the cell surface. Of these ligands, lprG appears to bind DC-SIGN via typical proteinglycan interactions, but DnaK and Cpn60.1 binding do not show evidence of carbohydrate-dependent interactions. LprG was also identified as a ligand for DC-SIGNR (L-SIGN; CD299) and the M. tuberculosis orthologue of lprG has been found previously to interact with human toll-like receptor 2. Collectively, these findings offer new targets for combating mycobacterial adhesion and within-host survival, and reinforce the role of DCSIGN as an important host ligand in mycobacterial infection.
Amino Acid Sequence ; Bacterial Adhesion ; physiology ; Bacterial Proteins ; genetics ; metabolism ; Cell Adhesion Molecules ; genetics ; metabolism ; Chromatography, Affinity ; Dendritic Cells ; metabolism ; microbiology ; Host-Pathogen Interactions ; genetics ; physiology ; Humans ; In Vitro Techniques ; Lectins, C-Type ; genetics ; metabolism ; Ligands ; Macrophages ; metabolism ; microbiology ; Mass Spectrometry ; Membrane Proteins ; genetics ; metabolism ; Models, Biological ; Molecular Chaperones ; genetics ; metabolism ; Molecular Sequence Data ; Mycobacterium bovis ; genetics ; metabolism ; Mycobacterium tuberculosis ; genetics ; metabolism ; pathogenicity ; Pulmonary Surfactant-Associated Protein A ; metabolism ; Receptors, Cell Surface ; genetics ; metabolism

OBJECTIVEAlveolar epithelium impairment is one of pathological changes associated with chronic lung disease (CLD). Hoxb5 is one of the few homeobox genes strongly expressed in the developing lung. This study investigated the expression of HoxB5, SPC and AQP5 in rats with CLD in order to explore the role of Hoxb-5 in impairment and reparation of alveolar epithelium.

METHODSEighty neonatal rats were randomly exposed to hyperoxia (model group) or to room air (control group) (n=40 each). The CLD model was induced by hyperoxia exposure. The expression of HoxB5, SPC and AQP5 protein and mRNA in the lung tissue was detected by immunohistochemistry and RT-PCR 1, 3, 7, 14 and 21 days after exposure.

RESULTSIn the model group HoxB5 expression significantly decreased 7, 14 and 21 days after hyperoxia exposure. SPC expression decreased 3 days after hyperoxia exposure but increased significantly 7, 14 and 21 days after hyperoxia exposure as compared to the control group. AQP5 expression was progressively reduced with prolonged hyperoxia exposure.

CONCLUSIONSHyperoxia exposure may lead to alveolar epithelial cell (AEC) damage in neonatal rats. The increased SPC expression and decreased AQP5 expression suggested that the ability of differentiation and transformation of AECII into AECI decreased in neonatal rats with CLD. The decreased HoxB5 expression following hyperoxia exposure might contribute to a decreased ability of differentiation of AECII.

Animals ; Animals, Newborn ; Aquaporin 5 ; analysis ; genetics ; Chronic Disease ; Female ; Homeodomain Proteins ; analysis ; genetics ; Hyperoxia ; complications ; Immunohistochemistry ; Lung ; pathology ; Lung Diseases ; etiology ; metabolism ; Male ; Pulmonary Surfactant-Associated Protein C ; analysis ; genetics ; RNA, Messenger ; analysis ; Rats ; Rats, Wistar ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVE: To investigate the distribution of pulmonary surfactant protein A (SP-A) like molecules and the bridge of frontier host defense and adaptive immune response cell of CD68 positive macrophages in inflammatory bowel disease (IBD). METHODS: Surgical specimens derived from involved areas and normal area of the colon with Crohn disease (CD) and ulcerative colitis (UC) were obtained from Department of Pathology, Rhode Island Hospital, Brown University Medical Center. The distribution of SP-A like molecule in intestine of IBD was detected by immunohistochemistry. RESULTS: SP-A like molecule located in epithelia of intestine, the surface of intestine villi, blood vessels of connective tissue, and some inflammatory cells. The number of macrophages with both SP-A like molecule and CD68 positive was dramatically increased in the inflammatory area than the normal area. Some CD68 positive macrophages expressed SP-A like immunoreactivity by immunofluorescence double labeling. CONCLUSION SP-A is an important host defense molecule in lung, and SP-A expression in large intestine may reflect a close relation between 2 organs in immune response towards inflammation.
Antigens, CD ; metabolism ; Antigens, Differentiation, Myelomonocytic ; metabolism ; Colitis, Ulcerative ; immunology ; metabolism ; Colon ; metabolism ; Crohn Disease ; immunology ; metabolism ; Humans ; Immunohistochemistry ; Inflammatory Bowel Diseases ; immunology ; metabolism ; Macrophages ; immunology ; metabolism ; Pulmonary Surfactant-Associated Proteins ; genetics ; metabolism

OBJECTIVETo investigate the effects of maternally administered dexamethasone and ambroxol on the mRNA levels of surfactant proteins (SP-A, SP-B and SP-C) expression in fetal rat lungs at gestational age day 19.

METHODSA 19-day fetal rat lung model was employed. In situ hybridization was used to detect the expression of SP-B mRNA in alveolar type II cell, and the levels of SP-A, SP-B and SP-C mRNAs were detected by semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS(1) SP-B mRNA was detected in situ in alveolar type II cells in fetal rat lung of day 19 gestational age; (2) In the late developmental period of fetal rat lungs, alveolar type II cells were also found around bronchus; (3) Comparing to beta-actin mRNA, the relative values of SP-A, SP-B and SP-C mRNAs were 0.81 +/- 0.26, 0.97 +/- 0.20 and 0.88 +/- 0.11 in fetal lung in the control group. The relative values of mRNAs of SP-A, SP-B and SP-C to beta-actin were 1.04 +/- 0.16, 1.28 +/- 0.29, 1.09 +/- 0.25 in fetal lungs of the ambroxol injected rats, and were 1.08 +/- 0.25, 1.23 +/- 0.35, 1.21 +/- 0.25 in fetal lungs of the dexamethasone injected rats, respectively. Both ambroxol and dexamethasone-treated rats had significantly higher mRNA expression of surfactant proteins compared to the control saline injected animals (P < 0.05). (4) There were no significant differences between ambroxol and dexamethasone in the effects of increasing expressions of surfactant protein mRNAs (P > 0.05).

CONCLUSIONAntepartum administration of both ambroxol and dexamethasone can significantly increase fetal lung SP-A, SP-B and SP-C mRNAs expression.

Ambroxol ; pharmacology ; Animals ; Dexamethasone ; pharmacology ; Expectorants ; pharmacology ; Female ; Gene Expression Regulation, Developmental ; drug effects ; Glucocorticoids ; pharmacology ; Lung ; drug effects ; embryology ; metabolism ; Pregnancy ; Pulmonary Surfactant-Associated Protein A ; genetics ; Pulmonary Surfactant-Associated Protein B ; genetics ; Pulmonary Surfactant-Associated Protein C ; genetics ; Pulmonary Surfactant-Associated Proteins ; genetics ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Wistar ; Reverse Transcriptase Polymerase Chain Reaction

BACKGROUND: All organisms have developed an internal timing system capable of reacting to and anticipating environmental stimuli with a program of appropriately timed metabolic, physiologic and behavioral events. The alveolar epithelial type II cell of the mammalian lung synthesizes, stores, and secretes a lipoprotein pulmonary surfactant, which functions to stabilize alveoli at low lung volumes. METHODS: The authors investigated the diurnal variation of surfactant protein A, B and C mRNA accumulation. The diurnal variation on gene expression of surfactant protein A, B and C was analysed using filter hybridization at 9 a.m., 4 p.m. and 11 p.m. Lung SP-A protein content was determined by double sandwich ELISA assay using a polyclonal antiserum raised in rabbits against purified rat SP-A. RESULTS: 1. The accumulation of SP-A mRNA at 4 p.m. was significantly decreased by 23.5% compared to the value at 9 a.m. (p< 0.05). 2. The accumulation of SP-B mRNA at 4 p.m. and 11 p.m. was decreased by 15.1% and 5.7%, respectively, compared to the value at 9 a.m. (p=0.07, p=0.69). 3. The accumulation of SP-C mRNA at 4 p.m. and 11 p.m. was decreased by 6.8% and 7.7%, respectively, compared to the value at 9 a.m. (p=0.38, p=0.57). 4. Total lung SP-A content at 4 p.m. and 11 p.m. was increased by 5.3% and 15.9%, respectively, compared to the value at 9 a.m. (p=0.64, p=0.47). CONCLUSION: These findings represent the diurnal variation of surfactant proteins mRNA expression in vivo. These results indicated that the diurnal variation of significant gene expression is observed in hydrophilic surfactant protein rather than in hydrophobic surfactant proteins.
Animals ; *Circadian Rhythm ; Enzyme-Linked Immunosorbent Assay ; Gene Expression ; Pulmonary Surfactant-Associated Proteins/genetics/*metabolism ; RNA, Messenger/*metabolism ; Rats ; Rats, Sprague-Dawley