Alteration of surfactant proteins A and D in bronchoalveolar lavage fluid of pneumocystis carinii pneumonia

Objective To understand the interaction between surfactant proteins and pneumocystis carinii pneumonia (PCP),and the impact of corticosteriods on surfactant proteins.Methods We established rat models of PCP and bacterial pneumonia induced by subcutaneous injection of 25mg cortisone acetate.At 8- 12 wk,the bronchoalveolar lavage fluid(BALF)of rats was collected.Total nucleated cells of BALF were counted and differentiated,and the concentrations of surfactant protein A(SP-A)and surfactant protein D(SP-D)were measured by immunoblotting assay.The rats were divided into three immunosuppressive groups and a normal control group.Group I,normal control(n = 6),consisted of healthy SD rats;group Ⅱ,negative control(n = 6),consisted of rats with cortisone acetate injection for over 8 wk without lung infection;group Ⅲ,bacterial pneumonia(n = 11),rats were injected with cortisone acetate over 8 wk that resulted in bacterial pneumonia without other pathogens isolated;and group Ⅳ,PCP(n = 14),rats with injected cortisone acetate for 8 - 12 wk and developed PCP without other pathogens isolated.Results Our results indicated that the total cell count in BALF in the negative control group was lower than that in the normal control group(P ＜ 0.001).During PCP infection,the total cell count and the percentage of polymorphonuclearcytes(PMNs)in BALF were significantly increased(P ＜ 0.01),but were lower than those in the bacterial pneumonia group.The concentration of SP-A of BALF in PCP(45.1 ± 22.1 μg/ml)was significantly increased in comparison with that in the negative control(16.2 ± 9.9 μg/ml,P ＜ 0.05)and bacterial pneumonia groups(6.2 ± 5.6 μg/ml,P ＜ 0.001).We also found that the relative content of SP-D was significantly higher in PCP(24249 ±4780 grey values)than that in the negative control (13 384 ± 2887 grey values,P ＜ 0.001)and that in bacterial pneumonia(11 989 ± 2750 grey values,P＜0.001).SP-A and SP-D were also higher in the moderate to heavy group of PCP than those seen in the mild group(P ＜ 0.01,P ＜ 0.001).SP-A and SP-D were higher in the negative control group than those in the normal control group,but there was no significant difference between the 2 groups.Conclusion These results suggest that the concentrations of SP-A and SP-D in BALF are increased by pneumocystis carinii specific stimulation,but the alteration is not related to the corticosteriod usage.

Early expression of surfactant proteins D in Fusarium solani infected rat cornea

AIM: To investigate the early expression of surfactant proteins D(SP-D) in Fusarium solani infected rat cornea. METHODS: Wistar rats were divided into group A, B and C randomly. The right eyes were chosen as the experiment one. Group A was control group. Group B was not inoculated with Fusarium solani. Group C was taken as fusarium solani keratitis model. Five rats in group B and C were executed randomly at 6, 12, 24, 48 and 96 hours respectively after the experimental model being established. The expression of SP-D was assessed through immunohistochemistry and reverse transcription polyrnerase chain reaction(RT-PCR). RESULTS: RT-PCR detected that the SP-D mRNA expression was low in the corneal of normal rats and group B. The expression of fungal infected cornea increased gradually and reached the peak at 24 hours in group C. The synchronous expression of group B and C were in significant difference (P<0.01). Immunohistochemisty discovered the protein of SP-D expression was increased gradually from 12 hours and reached the peak at 48 hours in group C. The synchronous expression of group B and C were also in significant difference (P<0.01). CONCLUSION: There exists SP-D in rat corneal tissue and the expression is significantly increased at the early period of fusarium solani infected cornea. SP-D may play a role in the early innate immunity response of the corneal resistance to Fusarium solani infection.

The roles of surfactant protein D during Aspergillus fumigatus infection in human corneal epithelial cells

AIM: To investigate roles of surfactant protein D (SP-D) and relative cytokines in human corneal epithelial (HCE) cells Exposed to aspergillus fumigatus (AF) antigens. METHODS: HCE cells cultured 47 in vitro with AF antigens and sampled at 0, 0.5, 1 hour, 2, 4, 6 and 8 hours. The Expression of SP-D mRNA was evaluated by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR).The expression of SP-D protein was shown by ELISA and immunocytochemistry SP methods. The expression of NF-kappa B and relative downstream cytokines such as TNF-alpha, IL-1 beta, IL-8 and IL-10 in supernatant fluid were measured by ELISA. RESULTS: SP-D mRNA and protein were detected in untreated HCE cells. The expression of SP-D and the relative downstream cytokines rose after being stimulated with AF antigens. SP-D mRNA began to rise at 0.5 hour and the most significantly peak was in 2 hours. The protein of SP-D in supernatant fluid had the same trend with mRNA. Immunocytochemistry of SP-D showed positive expression and gradually increased to 6 hours, and then the expression began to decline. NF-kappa B was activated after treated by AF antigens and the changes had correlation with SP-D. TNF-alpha, IL-1 beta, IL-8 and IL-10 began to rise after given AF antigens 1 hour and were 1.82, 1.43, 1.12 and 1.28 times higher than the untreated HCE cells separately. The expression of TNF-alpha and IL-1 beta reached the peak at 2 hours, separately 2.80 and 2.86 times than the untreated. The expression of IL-8 and IL-10 gradually increased with a time-dependent manner. ' CONCLUSION: HCE cells exists SP-D and it may play a significant role in pathogenesis of keratomycosis. AF may induce human corneal epithelial cells to express inflammatory cytokines via SP-D and NF-kappa B pathway. SP-D possibly mediates the recognition to AF mycelium.

Surfactant Protein B 1580 Polymorphism Is Associated with Susceptibility to Chronic Obstructive Pulmonary Disease in Chinese Han Population

Summary: Whether surfactant protein B (SP-B)-18A/C and 1580C/T polymorphism were associated with susceptibility to chronic obstructive pulmonary disease (COPD) in Chinese Han population was investigated. After genomic DNA was isolated from blood of COPD smokers and control smokers, the genotypes of SP-B-18A/C and SP-B1580C/T polymorphism loci were determined by polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP) respectively. The results showed that there was significant difference in genotypes distribution frequency of SP-B1580C/T polymorphism locus between COPD smokers and control smokers. C→T mutation rate (including TT homozygote and CT heterozygote) in COPD smokers was higher than in control smokers (57.9 % vs 41.7 %, χ2=4.93, P<0.05), whereas there was no significant difference in genotypes distribution frequency of SP-B1580-18A/C locus between COPD smokers and control smokers. The allele frequency (29.1 %) of SP-B1580-18A/C locus is lower than T allele (70.9 %) in Chinese Han Population, and the distribution was different from that in Mexican, in which, the A and T allele frequencies were 85 % and 15 % respectively. It was concluded that SP-B1580 T allele was probably associated with increased susceptibility to COPD in Chinese Han population; The polymorphism of SP-B-18A/C locus maybe varied with race.

Expression of Peroxiredoxins and Pulmonary Surfactant Protein A Induced by Silica in Rat Lung Tissue

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.

Association of Surfactant Protein B Gene Polymorphisms (C/A-18, C/T1580, Intron 4 and A/G9306) and Haplotypes with Bronchopulmonary Dysplasia in Chinese Han Population

Summary： This study aimed to investigate the association between surfactant protein B （SP-B） pol- ymorphisms and bronchopulmonary dysplasia （BPD） in Chinese Han infants. We performed a case- control study including 86 infants with BPD and 156 matched controls. Genotyping was performed by sequence specific primer-polymerase chain reaction （PCR） and haplotypes were reconstructed by the fastPHASE software. The results showed that significant differences were detected in the geno- type distribution of C/A-18 and intron 4 polymorphisms of SP-B gene between cases and controls. No significant differences were detected in fhe genotype distribution of C/T1580 or A/G9306 be- tween the two groups. Haplotype analysis revealed that the frequency of A-del-C-A haplotype was higher in case group （0.12 to 0.05, P=0.003）, whereas the frequency of C-inv-C-A haplotype was higher in control group （0.19 to 0.05, P=0.000）. In addition, a significant difference was observed in the frequency of C-inv-T-A haplotype between the two groups. It was concluded that the polymor- phisms of SP-B intron 4 and C/A-18 could be associated with BPD in Chinese Han infants, and the del allele of intron 4 and A allele of C/A-18 might be used as markers of susceptibility in the disease. Haplotype analysis indicated that the gene-gene interactions would play an important part in deter- mining susceptibility to BPD.

Surfactant Protein A Polymorphism Is Associated with Susceptibility to Chronic Obstructive Pulmonary Disease (COPD) in Chinese Uighur Population

This study investigatedexamined the correlation between surfactant protein-A (SP-A) polymorphism and the susceptibility of cvhronic obstructive pulmonary disease (COPD) in Xinjiang Uighurs. Genomic DNA was extracted from peripheral blood of 194 COPD smokers and 201 healthy smokers of Uighur who were hospitalized in or paid a visit to one of the four Xingjiang-based hospi-tals involved in the study, betweenfrom March 2009 to December 2010. Single nucleotide polymor-phisms (SNPs) were studied on A/G atwithin amino acid aa62 (CCA/CCG rs1136451) and C/T within aa219 (CGG/TGG, rs4253527) in SP-A. Genotypes were determined by using the TaqMan polymerase chain reaction (PCR). Our results showed that genotype frequencies were different be-tween the COPD and normal smokers infor aa62 (χx2=6.852, P=0.033). There were also significant differences in allele genotype frequencies between the COPD and the control and allele G might de-crease the risk COPD (χx2=6.545, P=0.011; OR=0.663; 95% CI: 0.484–0.909). The result suggested We were led to conclude that polymorphism of aa62 (CCA/CCG, rs1136451) of SP-A may be asso-ciated with the susceptibility to COPD in Xingjiang Uighurs.

Fetal lung surfactant and development alterations in intrahepatic cholestasis of pregnancy

AIM: To investigate the association between total bile acid(TBA) level during intrahepatic cholestasis of pregnancy(ICP) and fetal lung surfactant alteration. METHODS: We recruited 42 ICP and 32 normal pregnancy women in this study. The maternal blood, fetal blood and amniotic fluid TBA level were detected using a circulating enzymatic method. Umbilical blood pulmonary surfactant protein A(SP-A) was evaluated with enzyme-linked immunosorbent assay. High performance liquid chromatography was used for the determination of phosphatidyl choline(PC), phosphatidyl inositol(PI), lysolecithin(LPC) and sphingomyelin(SM). Amniotic fluid lamellar body was counted with a fully automatic blood cell counter. Fetal lung area and fetal body weight were calculated from data obtained with an iu22 color supersonic diagnostic set. Clinical information of a nonstress test, amniotic fluid properties and neonatal Apgar score, and birth weight were recorded for review. RESULTS: The TBA level in maternal blood, fetal blood and amniotic fluid in the ICP group were significantly higher than that in the control group(maternal blood: 34.11 ± 6.75 mmol/L vs 4.55 ± 1.72 mmol/L, P < 0.05; fetal blood: 11.9 ± 2.23 mmol/L vs 3.52 ± 1.56 mmol/L, P < 0.05; amniotic fluid: 3.89 ± 1.99 mmol/L vs 1.43 ± 1.14 mmol/L, P < 0.05). Amniotic fluid PC and PI in the ICP group were significantly lower than that in the control group(PC: 65.71 ± 7.23 μg/m L vs 69.70 ± 6.68 μg/m L, P < 0.05; PI: 3.87 ± 0.65 μg/m L vs 4.28 ± 0.74 μg/m L, P < 0.05). PC/LPC ratio of the ICP group was lower than that of the control group(14.40 ± 3.14 vs 16.90 ± 2.52, P < 0.05). Amniotic LB in the ICP group was significantly lower than that of the control group((74.13 ± 4.37) × 109/L vs(103.0 ± 26.82) × 109/L, P < 0.05). Fetal umbilical blood SP-A level in the ICP group was significantly higher than that of the control group(30.26 ± 7.01 ng/m L vs 22.63 ± 7.42 ng/m L, P < 0.05). Fetal lung area/body weight ratio of the ICP group was significantly lower than that of the control group(5.76 ± 0.63 cm2/kg vs 6.89 ± 0.48 cm2/kg, P < 0.05). In the ICP group, umbilical cord blood TBA concentration was positively correlated to the maternal blood TBA concentration(r = 0.746, P < 0.05) and umbilical blood SP-A(r = 0.422, P < 0.05), but it was negatively correlated to the amniotic fluid lamellar corpuscle(r = 0.810, P < 0.05) and fetal lung area/body weight ratio(r = 0.769, P < 0.05). Furthermore, umbilical blood TBA showed a negative correlation to PC, SM and PI(r pc = 0.536, r sm = 0.438, r pi = 0.387 respectively, P < 0.05). The neonatal asphyxia, neonatal respiratory distress syndrome, fetal distress and perinatal death rates in the ICP group are higher than that of theCONCLUSION: ICP has higher TBA in maternal and fetal blood and amniotic fluid. The high concentration of TBA may affect fetal pulmonary surfactant production and fetal lung maturation.

Pulmonary Immunohistochemical Detection of Surfactant Protein A (SP-A) in Fatal Drowning

Drowning still remains one of the most difficult diagnoses in forensic pathology because macroscopic and microscopic autopsy findings are unspecific. An ideal diagnostic marker for drowning still needs to be developed, but some authors have recently studied SP-A as a marker of asphyxiation and drowning. The aim of this study is to compare the histopathological features and the SP-A immunohistochemical expression in lung tissue in the case of drowning with those determined by other causes to discriminate between cadaver submersion and drowning.

Surfactant Protein D for Pathological Evaluation of Infant Acute Respiratory Distress Syndrome Caused by Respiratory Syncytial Virus Infection

Pediatric respiratory syncytial viral infection (RS) usually shows relatively good outcome;however, when it accompanies acute respiratory distress syndrome (ARDS), this becomes fatal. We experienced three pediatric patients with RS + ARDS, with all showing good outcome with steroid pulse therapy. We wish to emphasize;1) steroid pulse therapy may become an option for this condition, and 2) plasma KL-6 and surfactant protein D levels may become a biomarker reflecting the disease progression/condition. Patients were, aged 1 month, 1 year 5 months, and 1 year 11 months. In all three, the respiratory condition deteriorated rapidly, requiring invasive ventilator management. Although the effectiveness of steroid treatment for ARDS is controversial, very severe condition prompted us to employ steroid pulse therapy, after which, oxygenation rapidly improved without adverse events. Plasma KL-6 and surfactant protein D levels were measured during exacerbations of ARDS, steroid pulse therapy, and recovery. Surfactant protein D levels were closely associated with oxygenation, suggesting this substance level might be a biomarker of ARDS caused by the disruption of the alveolar epithelial lining and to understand oxygenation without time lag.

Clinical-pathological and molecular characterization of long-term survivors with advanced non-small cell lung cancer

Objective:Long-term survivors(LS)of non-small cell lung cancer(NSCLC)without driver alterations,displaying an overall survival(OS)of more than 3 years,comprise around 10%of cases in several series treated with chemotherapy.There are classical prognosis factors for these cases[stage,Eastern Cooperative Oncology Group(ECOG),etc.],but more data are required in the literature.In this multi-center study,we focused on LS of advanced NSCLC with OS above 36 months to perform a clinical-pathological and molecular characterization.Methods:In the first step,we conducted a clinical-pathological characterization of the patients.Afterwards,we carried out a genetic analysis by comparing LS to a sample of short-term survivors(SS)(with an OS less than 9 months).We initially used whole-genome RNA-seq to identify differentiating profiles of LS and SS,and later confirmed these with reverse transcription-polymerase chain reaction(RT-PCR)for the rest of the samples.Results:A total of 94 patients were included,who were mainly men,former smokers,having adenocarcinoma(AC)-type NSCLC with an ECOG of 0-1.We obtained an initial differential transcriptome expression,displaying 5 over-and 33 under-expressed genes involved in different pathways:namely,the secretin receptor,surfactant protein,trefoil factor 1(T FF1),serpin,Ca-channels,and Tolllike receptor(TLRs)families.Finally,RT-PCR analysis of 40(20 LS/20 SS)samples confirmed that four genes(surfactant proteins and SFTP)were significantly down-regulated in SS compared to LS by using an analysis of covariance(ANCOVA)model:SFTPA1(P=0.023),SFTPA2(P=0.027),SFTPB{P=0.02),and SFT PC(P=0.047).Conclusions:We present a sequential genetic analysis of a sample of NSCLCLS with no driver alterations,obtaining a differential RNA-seq/RT-PCR profile showing an abnormal expression of SF genes.

Effect of SP-A/B in lipoic acid on acute paraquat poisoning

BACKGROUND: This study was undertaken to observe the concentration of SP-A/B and the pulmonary surfactant in the lung tissue of rats with acute lung injury/acute respiratory distress syndrome caused by paraquat poisoning after the treatment of metabolic antioxidant-lipoic acid and whether its influence was related to TNF-α.METHODS: Sixty-six male Sprage-Dawley rats were randomly divided into three groups: normal control group(NS group), 6 rats; paraquat poisoning group(PQ group), 30 rats; and paraquat+lipoic acid treatment group(LA group), 30 rats. The rats in the PQ and LA groups were subdivided into 3-, 6-, 12-, 24-, 48-hour subgroups, with 6 rats in each group. After the rats were sacrificed, lung tissue from the same part was taken from the rats. After HE staining, histological changes were observed in the tissue under a light microscope. Lung tissue was also taken to test the levels of superoxide dismutase(SOD) and malondialdehyde(MDA). Whole blood(0.8 mL) without anticoagulant was drawn from the tail vein of rats for the determination of the TNF-α level. The total RNA of the lung tissue was collected, and the Rt-PCR method was used to measure the levels of SP-A and SP-B mRNA.RESULTS: HE staining showed that histopathological changes were milder in the LA group than in the PQ group. There were significant differences in MDA and SOD levels between different intervals both in intergroups and intragroups except the 3-hour subgroup(P<0.01). Likewise, the significant differences in the levels of TNF-α were also present between the three groups and between different intervals(P<0.01). The significant differences in SP-A mRNA and SP-B mRNA amplification ratio were seen between the three groups at the same intervals(P<0.01), but the differences between different intervals in the PQ group were statistically significant(P<0.05). The differences between different intervals in the LA group were statistically significant(P<0.01).CONCLUSION: Lipoic acid in acute paraquat poisoning could diminish lung tissue damage by regulating directly tumor necrosis factor and indirectly the content of pulmonary surfactant so as to reduce pulmonary edema, improve lung compliance, and finally protect lung tissues.

A study of histogenesis of pulmonary sclerosing hemangioma

Objective： To investigate the histogenesis and differential diagnosis of pulmonary sclerosing hemangioma （PSH）. Methods： Thyroid transcription factor-1 （TTF-1）, surfactant proteins A, B （SP-A, SP-B）, epithelial membrane antigen （EMA）, vimentin, pancytokeratin, cytokeratin7 （CK7）, CK5/6, calretinin, S-100, neurospecific enolase （NSE）, synaptophysin （Syn）, chromogranin A （CgA）, CD34, factor-Ⅷ-related antigen （F-Ⅷ） and smooth muscle actin （SMA）in 55 patients with PSH were examined with immunohistochemistry, while samples from 19 patients were also observed by electron microscope. Follow-up information were reviewed. Results： Pathologically, PSH mainly consisted of both surface lining cuboidal cells and pale polygonal cells. Immunohistochemitry revealed that coexpression of TTF-1, EMA and vimentin in both cuboidal and polygonal cells was 94.5 % （52/55）, 90.5% （50/55） and 58.2% （32/55）, respectively. In cuboidal cells, the expression of SP-A and SP-B was 92.7% （51/55） and 81.8 % （45/55）, respectively. Whereas pancytokeratin and CK7 immunostained the cuboidal cells in all cases. The polygonal cells were difussed immunostained with Syn in 13 PSHs （24%） and NSE in 8 PSHs （15%）, while immunoreactions with S-100 and CgA were separated detected in 7 PSHs （13%）. There was no significant difference of TTF-1 and EMA expression between these two cells （χ^2 value was 1.371 and 3.352, respectively. P 〉 0.05）. In contrast, there was a significant difference of vimentin between them （χ^2 value was 17.720, P 〈 0.001）. Electron microcopy observation showed that ultrastructure may not differ from each other sometime. The follow-up was obtained for 49 cases ranged from 3 months to 14 years. 48 of them had no recurrence or metastasis except one case had recurrence. Conclusion： PSH may origin from the primitive respiratory epithelial. Polygonal and cuboidal cells are all parenchymal neoplasm cells. The concomitant examination of TTF-1, SPA, SP-B, EMA, virnentin and pancytokeratin may favor the diagnosis and differential diagnosis of PSH.

Surfactant protein D inhibits lipid-laden foamy macrophages and lung inflammation in chronic obstructive pulmonary disease

Increased levels of surfactant protein D (SP-D) and lipid-laden foamy macrophages (FMs) are frequently found under oxidative stress conditions and/or in patients with chronic obstructive pulmonary disease (COPD) who are also chronically exposed to cigarette smoke (CS). However, the roles and molecular mechanisms of SP-D and FMs in COPD have not yet been determined. In this study, increased levels of SP-D were found in the bronchoalveolar lavage fluid (BALF) and sera of ozone- and CS-exposed mice. Furthermore, SP-D-knockout mice showed increased lipid-laden FMs and airway inflammation caused by ozone and CS exposure, similar to that exhibited by our study cohort of chronic smokers and COPD patients. We also showed that an exogenous recombinant fragment of human SP-D (rfhSP-D) prevented the formation of oxidized low-density lipoprotein (oxLDL)-induced FMs in vitro and reversed the airway inflammation and emphysematous changes caused by oxidative stress and CS exposure in vivo. SP-D upregulated bone marrow-derived macrophage (BMDM) expression of genes involved in countering the oxidative stress and lipid metabolism perturbations induced by CS and oxLDL. Our study demonstrates the crucial roles of SP-D in the lipid homeostasis of dysfunctional alveolar macrophages caused by ozone and CS exposure in experimental mouse emphysema, which may provide a novel opportunity for the clinical application of SP-D in patients with COPD.

Effect of surfactant protein A on lipopolysaccharide-induced tumor necrosis factor-α expression in human proximal tubular epithelial cells

Background Surfactant protein A （SP-A） contributes to the regulation of sepsis-induced acute lung injury.In a previous study,we demonstrated the expression and localization of SP-A in the kidneys.The present study evaluated the effect of SP-A on lipopolysaccharide （LPS）-induced tumor necrosis factor-α （TNF-α） expression and its underlying mechanisms in the human renal tubular epithelial （HK-2） cells.Methods Indirect immunofiuorescence assay was used to detect SP-A distribution and expression in HK-2 cells.HK-2 cells were treated with various concentrations of LPS （0,0.1,1,2,5,and 10 mg/L） for 8 hours and with 5 mg/L LPS for different times （0,2,4,8,16,and 24 hours） to determine the effects of LPS on SP-A and TNF-α expression.Then,HK-2 cells were transfected with SP-A siRNA to analyze nuclear factor κB （NF-κB） P65 and TNF-α expression of HK-2 cells after LPS-treatment.Results Indirect immunofluorescence assay revealed that SP-A is localized to the membrane and cytoplasm of HK-2 cells.Interestingly,SP-A1/SP-A2 and TNF-α expression were found to be significantly increased in HK-2 cells upon LPS treatment.Transfection of LPS-treated HK-2 cells with SP-A siRNA resulted in significant increases in the levels of NF-κB P65 protein and TNF-α mRNA and protein compared to those in non-transfected LPS-treated HK-2 cells.Conclusion SP-A plays an important role in protecting cells against sepsis-induced acute kidney injury by inhibiting NF-κB activity to modulate LPS-induced increase in TNF-α expression.

GM130 regulates pulmonary surfactant protein secretion in alveolar typeⅡcells

Pulmonary surfactant is a lipid-protein complex secreted by alveolar typeⅡepithelial cells and is essential for the maintenance of the delicate structure of mammalian alveoli to promote efficient gas exchange across the air-liquid barrier.The Golgi apparatus plays an important role in pulmonary surfactant modification and secretory trafficking.However,the physiological function of the Golgi apparatus in the transport of pulmonary surfactants is unclear.In the present study,deletion of GM130,which encodes for a matrix protein of the cis-Golgi cisternae,was shown to induce the disruption of the Golgi structure leading to impaired secretion of lung surfactant proteins and lipids.Specifically,the results of in vitro and in vivo analysis indicated that the loss of GM130 resulted in trapping of Sftpa in the endoplasmic reticulum,Sftpb and Sftpc accumulation in the Golgi apparatus,and an increase in the compensatory secretion of Sftpd.Moreover,global and epithelial-specific GM130 knockout in mice resulted in an enlargement of alveolar airspace and an increase in alveolar epithelial autophagy;however,surfactant repletion partially rescued the enlarged airspace defects in GM130-deficient mice.Therefore,our results demonstrate that GM130 and the mammalian Golgi apparatus play a critical role in the control of surfactant protein secretion in pulmonary epithelial cells.

Surfactant protein A (SP-A) binds to phosphatidylserine and competes with annexin V binding on late apoptotic cells

The role of surfactant protein A(SP-A)in the recognition and clearance of apoptotic cells is well established,but to date,it is still not clear which surface molecules of apoptotic cells are involved in the process.Here we present evidence that phosphatidylserine(PS)is a relevant binding molecule for human SP-A.The binding is Ca^(2+)-dependent and is not inhibited by mannose,suggesting that the sugar-binding site of the carbohydrate recognition domain(CRD)of SP-A is not involved.Flow cytometry studies on apoptotic Jurkat cells revealed apparent inhibition of annexin V binding by increasing concentrations of SP-A in late apoptotic but not early apoptotic cells,and this was consistent for Jurkat cells and neutrophils.Supporting these data,confocal microscopy results show a co-localisation of annexin V and SP-A in late apoptotic but not early apoptotic cells.However,we cannot conclude that this inhibition is exclusively due to the binding of SP-A to PS on the cell surface,as annexin V is not wholly specific for PS and SP-A also interacts with other phospholipids that might become exposed on the apoptotic cell surface.

Altered surfactant protein A gene expression and protein homeostasis in rats with emphysematous changes

Background The decrease of surfactant protein （SP） secreted by the alveolar type Ⅱ cell is one of the important causes of limiting air of pulmonary emphysema. However, the SP-A gene and protein changes in this disease are rarely studied. This study was undertaken to investigate alterations in SP-A gene activity and protein, and to explore their roles in the pathogenesis of emphysematous changes. Methods Twenty Wistar rats were divided randomly into a normal control group （n=10） and a cigarette smoking （CS） ＋ lipopolysaccharide （LPS） group （n=10）. Ultra-structural changes were observed under an electron microscope. The number of cells positive for SP-A was measured by immunohistochemistry. The mRNA expression and protein level of SP-A in the lung tissues were determined by quantitative polymerase chain reaction （qPCR） and Western blot separately. The protein level of SP-A in lavage fluid was determined by Western blot. Results The number of cells positive for SP-A of the CS＋LPS group （0.35±0.03） was lower than that of the blank control group （0.72±0.06, P 〈0.05）. The level of SP-A in the lung tissues of rats in the CS＋LPS group （0.2765±0.0890） was lower than that in the blank control group （0.6875±0.1578, P 〈0.05）. The level of SP-A in the lavage fluid of rats in the CS＋LPS group （0.8567±0.1458） was lower than that in the blank control group （1.3541±0.2475, P 〈0.05）. The lung tissues of rats in the CS＋LPS group showed an approximate increase （0.4-fold） in SP-A mRNA levels relative to β-actin mRNA （P 〈0.05）. Conclusions The changes of SP-A may be related to emphysematous changes in the lung. And cigarette smoke and LPS alter lung SP-A gene activity and protein homeostasis.

Aggravated pulmonary injury after subarachnoid hemorrhage in PDGF-B^ret/ret mice

Background:Recent advances in surgical and neuroprotective strategies could effectively manage the pathophysiological progression of subarachnoid hemorrhage(SAH).However,pulmonary dysfunction frequently occurs in SAH patients with an increased risk of unsatisfactory outcomes.Based on the similar microvascular structures in the blood-air barrier and blood-brain barrier and possible brain-lung crosstalks,we believe that pericytes may be involved in both neurological and pulmonary dysfunction after SAH.Methods:In our experiments,platelet-derived growth factor B(PDGF-B)retention motif knockout(PDGF-Bret/ret)mice and adeno-associated virus PDGF-B were employed to show the involvement of pericyte deficiency and PDGF-B expression.Neurological score,SAH grade,hematoxylin-eosin staining,and PaO2/FiO2 ratio analysis were performed to evaluate the neurological deficits and pulmonary functions in endovascular perforation SAH models at 24 h after surgery,as well as western blotting and immunofluorescence staining for underlying molecular expressions.Results:We found that neonatal PDGF-Bret/ret mice exhibited pulmonary atelectasis 12 h after birth.Further investigation showed a decrease in PaO2/FiO2 and lung-specific surfactant proteins in adult PDGF-Bret/ret mice.These dysfunctions were much worse than those in wild-type mice at 24 h after SAH.PDGF-B overexpression alleviated pulmonary dysfunction after SAH.Conclusions:These results suggested pulmonary dysfunction after SAH and the pivotal role of PDGF-B signaling for the pathophysiological process and future therapeutic targets of pulmonary injury treatment after SAH.Further studies are needed for pathophysiological investigations and translational studies on pulmonary injuries after SAH.