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Deleted in Malignant Brain Tumors 1 (DMBT1) is present in hyaline membranes and modulates surface tension of surfactant.

Müller H, End C, Renner M, Helmke BM, Gassler N, Weiss C, Hartl D, Griese M, Hafner M, Poustka A, Mollenhauer J, Poeschl J - Respir. Res. (2007)

Bottom Line: The effect of human recombinant DMBT1 on the function of bovine and porcine surfactant was measured by a capillary surfactometer.In vitro addition of human recombinant DMBT1 to the surfactants increased surface tension in a dose-dependent manner.The DMBT1-mediated effect was reverted by the addition of calcium depending on the surfactant preparation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Neonatology, Department of Pediatrics, University of Heidelberg, Im Neuenheimer Feld 153, 69120 Heidelberg, Germany. Hanna.Mueller@med.uni-heidelberg.de

ABSTRACT

Background: Deleted in Malignant Brain Tumors 1 (DMBT1) is a secreted scavenger receptor cysteine-rich protein that binds various bacteria and is thought to participate in innate pulmonary host defense. We hypothesized that pulmonary DMBT1 could contribute to respiratory distress syndrome in neonates by modulating surfactant function.

Methods: DMBT1 expression was studied by immunohistochemistry and mRNA in situ hybridization in post-mortem lungs of preterm and full-term neonates with pulmonary hyaline membranes. The effect of human recombinant DMBT1 on the function of bovine and porcine surfactant was measured by a capillary surfactometer. DMBT1-levels in tracheal aspirates of ventilated preterm and term infants were determined by ELISA.

Results: Pulmonary DMBT1 was localized in hyaline membranes during respiratory distress syndrome. In vitro addition of human recombinant DMBT1 to the surfactants increased surface tension in a dose-dependent manner. The DMBT1-mediated effect was reverted by the addition of calcium depending on the surfactant preparation.

Conclusion: Our data showed pulmonary DMBT1 expression in hyaline membranes during respiratory distress syndrome and demonstrated that DMBT1 increases lung surface tension in vitro. This raises the possibility that DMBT1 could antagonize surfactant supplementation in respiratory distress syndrome and could represent a candidate target molecule for therapeutic intervention in neonatal lung disease.

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Effects of increasing hrDMBT1 (A) and calcium (B) concentrations on surface activity of surfactant preparations. (A) Surface activity (assessed as openness of a capillary) decreased with increasing human recombinant DMBT1 concentrations (final concentrations: 0 – 330 μg/ml) in both surfactant preparations (final phospholipid concentration 1 mg/ml). 2-way-ANOVA showed a significant influence on surface tension for surfactant preparation (P = 0.0243) and for hrDMBT1 concentration (P < 0.0001) as well as an interaction between surfactant preparation and hrDMBT1 concentration (P = 0.0363). (B) Calcium chloride antagonized the decrease of surface activity in the surfactant preparations (final phospholipid concentration 1 mg/ml) induced by hrDMBT1 (final concentration: 200 μg/ml). Analysis of variance analysis stated an influence of surfactant preparation (P = 0.0004), of hrDMBT concentration (P < 0.0001) and an interaction between surfactant preparation and hrDMBT1 concentration (P = 0.0037). Note that the surface activity of Alveofact® decreased at a lower hrDMBT1 concentration than that of Curosurf® (A) and that calcium antagonized the hrDMBT1 effect at 1 mM, whereas Alveofact® required a calcium concentration >3 mM (B). Data are expressed as mean ± SEM.
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Figure 3: Effects of increasing hrDMBT1 (A) and calcium (B) concentrations on surface activity of surfactant preparations. (A) Surface activity (assessed as openness of a capillary) decreased with increasing human recombinant DMBT1 concentrations (final concentrations: 0 – 330 μg/ml) in both surfactant preparations (final phospholipid concentration 1 mg/ml). 2-way-ANOVA showed a significant influence on surface tension for surfactant preparation (P = 0.0243) and for hrDMBT1 concentration (P < 0.0001) as well as an interaction between surfactant preparation and hrDMBT1 concentration (P = 0.0363). (B) Calcium chloride antagonized the decrease of surface activity in the surfactant preparations (final phospholipid concentration 1 mg/ml) induced by hrDMBT1 (final concentration: 200 μg/ml). Analysis of variance analysis stated an influence of surfactant preparation (P = 0.0004), of hrDMBT concentration (P < 0.0001) and an interaction between surfactant preparation and hrDMBT1 concentration (P = 0.0037). Note that the surface activity of Alveofact® decreased at a lower hrDMBT1 concentration than that of Curosurf® (A) and that calcium antagonized the hrDMBT1 effect at 1 mM, whereas Alveofact® required a calcium concentration >3 mM (B). Data are expressed as mean ± SEM.

Mentions: We next aimed at exploring the effect of DMBT1 on two different surfactant preparations which are used in supplementation therapies for preterm infants. Upon ELISA measurements, there were neither detectable levels of DMBT1-homologues in bovine Alveofact® nor porcine Curosurf®. Surfactometer measurements demonstrated that the addition of hrDMBT1 to the surfactant preparations decreased the surface activity (i.e. increased the surface tension) of both Curosurf® and Alveofact® in a dose-dependent manner (Fig. 3). However, the hrDMBT1 concentration needed to reduce the surface activity by 50% was about 2.5 fold higher for Curosurf® (110 μg/ml hrDMBT1) than for Alveofact® (45 μg/ml hrDMBT1) indicating that Alveofact® is less resistant to the presence of DMBT1 (Fig. 3A). Analysis by 2-way-ANOVA showed a significant influence on surface tension depending on the surfactant preparation (P = 0.0243) and on the hrDMBT1 concentration (P < 0.0001) as well as an interaction between surfactant preparation and hrDMBT1 concentration (P = 0.0363), which confirmed that the concentration influence is different in the two surfactant preparations. Therefore, each surfactant preparation was investigated by a 1-way-ANOVA. For Alveofact® and Curosurf®, a highly significant influence of hrDMBT1 on the surface tension could be shown (P < 0.0001 or P = 0.0001, respectively).


Deleted in Malignant Brain Tumors 1 (DMBT1) is present in hyaline membranes and modulates surface tension of surfactant.

Müller H, End C, Renner M, Helmke BM, Gassler N, Weiss C, Hartl D, Griese M, Hafner M, Poustka A, Mollenhauer J, Poeschl J - Respir. Res. (2007)

Effects of increasing hrDMBT1 (A) and calcium (B) concentrations on surface activity of surfactant preparations. (A) Surface activity (assessed as openness of a capillary) decreased with increasing human recombinant DMBT1 concentrations (final concentrations: 0 – 330 μg/ml) in both surfactant preparations (final phospholipid concentration 1 mg/ml). 2-way-ANOVA showed a significant influence on surface tension for surfactant preparation (P = 0.0243) and for hrDMBT1 concentration (P < 0.0001) as well as an interaction between surfactant preparation and hrDMBT1 concentration (P = 0.0363). (B) Calcium chloride antagonized the decrease of surface activity in the surfactant preparations (final phospholipid concentration 1 mg/ml) induced by hrDMBT1 (final concentration: 200 μg/ml). Analysis of variance analysis stated an influence of surfactant preparation (P = 0.0004), of hrDMBT concentration (P < 0.0001) and an interaction between surfactant preparation and hrDMBT1 concentration (P = 0.0037). Note that the surface activity of Alveofact® decreased at a lower hrDMBT1 concentration than that of Curosurf® (A) and that calcium antagonized the hrDMBT1 effect at 1 mM, whereas Alveofact® required a calcium concentration >3 mM (B). Data are expressed as mean ± SEM.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2164949&req=5

Figure 3: Effects of increasing hrDMBT1 (A) and calcium (B) concentrations on surface activity of surfactant preparations. (A) Surface activity (assessed as openness of a capillary) decreased with increasing human recombinant DMBT1 concentrations (final concentrations: 0 – 330 μg/ml) in both surfactant preparations (final phospholipid concentration 1 mg/ml). 2-way-ANOVA showed a significant influence on surface tension for surfactant preparation (P = 0.0243) and for hrDMBT1 concentration (P < 0.0001) as well as an interaction between surfactant preparation and hrDMBT1 concentration (P = 0.0363). (B) Calcium chloride antagonized the decrease of surface activity in the surfactant preparations (final phospholipid concentration 1 mg/ml) induced by hrDMBT1 (final concentration: 200 μg/ml). Analysis of variance analysis stated an influence of surfactant preparation (P = 0.0004), of hrDMBT concentration (P < 0.0001) and an interaction between surfactant preparation and hrDMBT1 concentration (P = 0.0037). Note that the surface activity of Alveofact® decreased at a lower hrDMBT1 concentration than that of Curosurf® (A) and that calcium antagonized the hrDMBT1 effect at 1 mM, whereas Alveofact® required a calcium concentration >3 mM (B). Data are expressed as mean ± SEM.
Mentions: We next aimed at exploring the effect of DMBT1 on two different surfactant preparations which are used in supplementation therapies for preterm infants. Upon ELISA measurements, there were neither detectable levels of DMBT1-homologues in bovine Alveofact® nor porcine Curosurf®. Surfactometer measurements demonstrated that the addition of hrDMBT1 to the surfactant preparations decreased the surface activity (i.e. increased the surface tension) of both Curosurf® and Alveofact® in a dose-dependent manner (Fig. 3). However, the hrDMBT1 concentration needed to reduce the surface activity by 50% was about 2.5 fold higher for Curosurf® (110 μg/ml hrDMBT1) than for Alveofact® (45 μg/ml hrDMBT1) indicating that Alveofact® is less resistant to the presence of DMBT1 (Fig. 3A). Analysis by 2-way-ANOVA showed a significant influence on surface tension depending on the surfactant preparation (P = 0.0243) and on the hrDMBT1 concentration (P < 0.0001) as well as an interaction between surfactant preparation and hrDMBT1 concentration (P = 0.0363), which confirmed that the concentration influence is different in the two surfactant preparations. Therefore, each surfactant preparation was investigated by a 1-way-ANOVA. For Alveofact® and Curosurf®, a highly significant influence of hrDMBT1 on the surface tension could be shown (P < 0.0001 or P = 0.0001, respectively).

Bottom Line: The effect of human recombinant DMBT1 on the function of bovine and porcine surfactant was measured by a capillary surfactometer.In vitro addition of human recombinant DMBT1 to the surfactants increased surface tension in a dose-dependent manner.The DMBT1-mediated effect was reverted by the addition of calcium depending on the surfactant preparation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Neonatology, Department of Pediatrics, University of Heidelberg, Im Neuenheimer Feld 153, 69120 Heidelberg, Germany. Hanna.Mueller@med.uni-heidelberg.de

ABSTRACT

Background: Deleted in Malignant Brain Tumors 1 (DMBT1) is a secreted scavenger receptor cysteine-rich protein that binds various bacteria and is thought to participate in innate pulmonary host defense. We hypothesized that pulmonary DMBT1 could contribute to respiratory distress syndrome in neonates by modulating surfactant function.

Methods: DMBT1 expression was studied by immunohistochemistry and mRNA in situ hybridization in post-mortem lungs of preterm and full-term neonates with pulmonary hyaline membranes. The effect of human recombinant DMBT1 on the function of bovine and porcine surfactant was measured by a capillary surfactometer. DMBT1-levels in tracheal aspirates of ventilated preterm and term infants were determined by ELISA.

Results: Pulmonary DMBT1 was localized in hyaline membranes during respiratory distress syndrome. In vitro addition of human recombinant DMBT1 to the surfactants increased surface tension in a dose-dependent manner. The DMBT1-mediated effect was reverted by the addition of calcium depending on the surfactant preparation.

Conclusion: Our data showed pulmonary DMBT1 expression in hyaline membranes during respiratory distress syndrome and demonstrated that DMBT1 increases lung surface tension in vitro. This raises the possibility that DMBT1 could antagonize surfactant supplementation in respiratory distress syndrome and could represent a candidate target molecule for therapeutic intervention in neonatal lung disease.

Show MeSH
Related in: MedlinePlus