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

Silicosis is one of the most serious occupational diseases in China and dates back to centuries ago. In this study, we successfully established a rat model of silicosis by intratracheal silica injection for 28 days and determined hydroxyproline levels to evaluate collagen metabolism in lung homogenates. Oxidative stress status was evaluated by detecting catalase and glutathione peroxidase activities. Expression levels of peroxiredoxins (Prx I and Prx VI) were detected by Western blotting. Pulmonary surfactant protein A (SP-A) levels in rat serum and lung tissue were analyzed by ELISA, and SP-A and Prx expression levels in lung tissues were detected by immunohistochemistry. The results suggest that Prx proteins may be involved in pulmonary fibrosis induced by silica. Downregulation of SP-A expression caused due to silica is an important factor in the occurrence and development of silicosis.
Animals ; Disease Models, Animal ; Humans ; Lung ; enzymology ; metabolism ; Male ; Oxidative Stress ; Peroxiredoxin VI ; genetics ; metabolism ; Peroxiredoxins ; genetics ; metabolism ; Pulmonary Surfactant-Associated Protein A ; genetics ; metabolism ; Rats ; Silicon Dioxide ; toxicity ; Silicosis ; genetics ; metabolism

Alveolar epithelial type II (AT II) cells are essential for lung development and remodeling, as they are precursors for type I cells and also produce other non-repair cells (fibroblasts). Progenitor cells are believed to possess capability of multi-potent transdifferentiation, which is closely related to the niche, suggesting the importance of establishment of a lung progenitor cell niche model. We hypothesized that pulmonary surfactant-associated protein A (SPA) suicide gene system would cause AT II cell to kill itself through apoptosis and leave its niche. In vitro, the recombinant adeno-associated virus vectors-SPA-thymidine kinase (rAAV-SPA-TK) system was established to get targeted apoptotic AT II cells. The apoptosis of AT II cells was detected by using MTT. The results showed that cloned SPA gene promoter had specific transcriptional activity in SPA high expression cells, and SPA high expression cells (H441) transfected with TK gene had higher sensitivity to ganciclovir (GCV) than SPA low expression cells (A549). In vivo, increased apoptosis of AT II cells induced by GCV in rAAV-SPA-TK system was observed by TUNEL. Finally, the successful packaging and application of rAAV-SPA-TK system provide experimental basis to get specific lung progenitor cell (AT II) niche in vitro and in vivo.
Antiviral Agents ; pharmacology ; Apoptosis ; drug effects ; Cell Line, Tumor ; Cell Survival ; drug effects ; Cells, Cultured ; Dependovirus ; genetics ; Dose-Response Relationship, Drug ; Electrophoresis, Polyacrylamide Gel ; Epithelial Cells ; cytology ; drug effects ; metabolism ; Ganciclovir ; pharmacology ; Gene Expression Regulation, Neoplastic ; Genes, Transgenic, Suicide ; genetics ; Genetic Vectors ; genetics ; Humans ; In Situ Nick-End Labeling ; Luciferases ; genetics ; metabolism ; Promoter Regions, Genetic ; genetics ; Pulmonary Alveoli ; cytology ; metabolism ; Pulmonary Surfactant-Associated Protein A ; genetics ; metabolism ; Thymidine Kinase ; genetics ; metabolism

Cell Line ; Clustered Regularly Interspaced Short Palindromic Repeats ; genetics ; DNA ; metabolism ; Deoxyribonuclease I ; metabolism ; Embryonic Stem Cells ; cytology ; metabolism ; Homologous Recombination ; Humans ; Pulmonary Surfactant-Associated Protein C ; genetics

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

PURPOSE: Recently, Forkhead box M1 (FoxM1) was reported to be correlated with lung maturation and expression of surfactant proteins (SPs) in mice models. However, no study has been conducted in rabbit lungs despite their high homology with human lungs. Thus, we attempted to investigate serial changes in the expressions of FoxM1 and SP-A/B throughout lung maturation in rabbit fetuses. MATERIALS AND METHODS: Pregnant New Zealand White rabbits were grouped according to gestational age from 5 days before to 2 days after the day of expected full term delivery (F5, F4, F3, F2, F1, F0, P1, and P2). A total of 64 fetuses were enrolled after Cesarean sections. The expressions of mRNA and proteins of FoxM1 and SP-A/B in fetal lung tissue were tested by quantitative reverse-transcriptase real-time PCR and Western blot. Furthermore, their correlations were analyzed. RESULTS: The mRNA expression of SP-A/B showed an increasing tendency positively correlated with gestational age, while the expression of FoxM1 mRNA and protein decreased from F5 to F0. A significant negative correlation was found between the expression levels of FoxM1 and SP-A/B (SP-A: R=-0.517, p=0.001; SP-B: R=-0.615, p<0.001). CONCLUSION: Preterm rabbits demonstrated high expression of FoxM1 mRNA and protein in the lungs compared to full term rabbits. Also, the expression of SP-A/B was inversely related with serial changes in FoxM1 expression. This is the first report to suggest an association between FoxM1 and expression of SP-A/B and lung maturation in preterm rabbits.
Animals ; Blotting, Western ; Female ; Fetus/*metabolism ; Forkhead Transcription Factors/*metabolism ; Lung/*metabolism ; Pregnancy ; Pulmonary Surfactant-Associated Protein A/genetics/*metabolism ; Rabbits

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

OBJECTIVEThis study examined the effects of maternal deficiency of folic acid during pregnancy on pulmonary development and protein A (SP-A) expression in newborn rats in order to explore the possible mechanism of lung developmental disorders.

METHODSThirty-six adult Sprague-Dawley female rats were randomly assigned into two groups: control and study (n=18). The study and the control groups were fed with fodder containing folic acid or not respectively. Two weeks later, the female rats in the two groups copulated with normal male rats. Newborn rats were sacrificed at 1, 7 and 14 days after birth (8 pups at each time point). Lung sections were stained with hematoxylin and eosin for histological examination. SP-A expression of protein and mRNA were determined by immunohistochemistry and real-time quantitative RT-PCR, respectively.

RESULTSThe newborn rats from the study group showed damaged lung tissue structures. The mean optical density of type II cells with positive expression of SP-A decreased significantly from 1 to 14 days in newborn rats of the study group compared with the control newborn rats (P<0.05). The real-time quantitative RT-PCR showed that the expression of lung SP-A mRNA also decreased significantly from 1 to 14 days in newborn rats of the study group compared with control newborn rats (P<0.05).

CONCLUSIONSMaternal deficiency of folic acid during pregnancy can decrease the expression of SP-A in lung tissues of newborn rats, which might lead to the disorder of lung development maturation.

Animals ; Animals, Newborn ; Female ; Folic Acid Deficiency ; metabolism ; Immunohistochemistry ; Lung ; embryology ; Male ; Pregnancy ; Pregnancy Complications ; metabolism ; Pulmonary Surfactant-Associated Protein A ; analysis ; genetics ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo review the pathophysiology, evaluation, management, and outcomes of children with inherited disorders of surfactant metabolism due to mutations in the genes encoding surfactant proteins-B or -C (SFTPB, SFTPC), ATP binding cassette member A3 (ABCA3), and thyroid transcription factor (NKX2.1).

DATA SOURCESReview of the literature, previous work from the author's and collaborators' laboratories, St. Louis Children's Hospital Lung Transplant Database.

STUDY SELECTIONKey articles in the field, author's work.

RESULTSInherited disorders of surfactant metabolism present as acute, severe respiratory dysfunction in the neonatal period (SFTPB, ABCA3, NKX2.1) or as chronic respiratory insufficiency in later infancy and childhood which is of variable onset, severity, and course (SFTPC, ABCA3, NKX2.1). Diagnosis is established with sequencing the relevant genes; lung biopsy with electron microscopy is a useful adjunct. For surfactant protein-B and ABCA3 deficiency presenting with acute neonatal disease, treatment options are limited to lung transplantation or compassionate care. For the more chronic presentations of surfactant protein-C, ABCA3, and NKX2.1 associated disease, the natural history is variable and therefore individualized, supportive care is appropriate,

CONCLUSIONSInherited disorders of surfactant metabolism are rare, but informative diseases that provide unique opportunities for understanding mechanisms of respiratory disease in newborns and children.

ATP-Binding Cassette Transporters ; genetics ; Humans ; Infant, Newborn ; Lung Diseases ; diagnosis ; etiology ; therapy ; Lung Transplantation ; Mutation ; Pulmonary Surfactant-Associated Protein B ; deficiency ; genetics ; Pulmonary Surfactant-Associated Protein C ; genetics ; Pulmonary Surfactants ; metabolism

BACKGROUNDLiver fibrosis is the process through which numerous chronic liver diseases develop into liver cirrhosis. Leptin can activate hepatic stellate cells (HSCs) and play an important role in the formation of liver fibrosis. However, the process by which leptin activates HSCs is complicated, and research on this process is limited. The aim of this study was to explore the related changes in gene expression and the control mechanisms involved in leptin activated HSCs to understand the overall mechanism of liver fibrosis development.

METHODSWe cultivate rat HSCs, with and without stimulation by leptin, and extracted mRNA. Differentially expressed genes were detected by microarray analysis.

RESULTSThe differentially expressed genes identified included six upregulated genes and six downregulated genes. The representative upregulated genes included short chain dehydrogenase (CY5/CY3 = 2.265) and pulmonary surfactant protein A1 (CY5/CY3 = 2.036). The significant downregulated gene encoded hepatic stearoyl coenzyme A desaturase 1 (SCD-1) (CY5/CY3 = 0.351).

CONCLUSIONLeptin might mediate the molecular biological mechanisms of liver fibrosis.

Animals ; Cells, Cultured ; Gene Expression Profiling ; Hepatic Stellate Cells ; drug effects ; metabolism ; Leptin ; pharmacology ; Oligonucleotide Array Sequence Analysis ; methods ; Pulmonary Surfactant-Associated Protein A ; genetics ; Rats ; Stearoyl-CoA Desaturase ; genetics