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 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.

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.

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.

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.