Differential susceptibility of transgenic mice expressing human surfactant protein B genetic variants to Pseudomonas aeruginosa induced pneumonia

Surfactant protein B (SP-B) is a developmentally and hormonally regulated lung protein that is required for normal surfactant function. We generated transgenic mice carrying the human SP-B promoter (−1,039/+431 bp) linked to chloramphenicol acetyltransferase (CAT). CAT activity was high in lung and immunoreactive protein localized to alveolar type II and bronchiolar epithelial cells. In addition, thyroid, trachea, and intestine demonstrated CAT activity, and each of these tissues also expressed low levels of SP-B mRNA. Developmental expression of CAT activity and SP-B mRNA in fetal lung were similar and both increased during explant culture. SP-B mRNA but not CAT activity decreased during culture of adult lung, and both were reduced by transforming growth factor (TGF)-β1. Treatment of adult mice with intratracheal bleomycin caused similar time-dependent decreases in lung SP-B mRNA and CAT activity. These findings indicate that the human SP-B promoter fragment directs tissue- and lung cell-specific transgene expression and contains cis-acting elements involved in regulated expression during development, fetal lung explant culture, and responsiveness to TGF-β and bleomycin-induced lung injury.

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The carboxy-teminal domain of human surfactant protein B is not required for secretion in milk of transgenic mice

Frontiers in Bioscience ◽

10.2741/a155 ◽

1997 ◽

Vol 2 (1) ◽

pp. a1-8 ◽

Cited By ~ 2

Author(s):

S. Yarus

Keyword(s):

Transgenic Mice ◽

Surfactant Protein ◽

Surfactant Protein B ◽

Protein B

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Membrane Activity of (Cys48Ser) Lung Surfactant Protein B Increases with Dimerisation

Biological Chemistry ◽

10.1515/bc.2001.116 ◽

2001 ◽

Vol 382 (6) ◽

pp. 933-939 ◽

Cited By ~ 12

Author(s):

Shahparak Zaltash ◽

William J. Griffiths ◽

David Beck ◽

Chen-Xia Duan ◽

Timothy E. Weaver ◽

...

Keyword(s):

Mass Spectrometry ◽

Transgenic Mice ◽

Ion Pairs ◽

Lung Surfactant ◽

Surfactant Protein ◽

Cd Spectroscopy ◽

Surfactant Protein B ◽

Lung Surfactant Protein ◽

Protein B

Abstract One of the possible functions of lung surfactant protein B (SPB), an hydrophobic membraneassociated saposinlike protein, is to reduce the alveolar surface tension by promoting insertion of phospholipids into the air/liquid interface of the lung. SPB is a covalent homodimer; Cys48 of two polypeptides form an intermolecular disulphide bond. In order to test whether dimerisation of SPB is important for surfactant function, transgenic mice which express (Cys48Ser) human SPB in a mouse SPB null background were generated. In previous studies (Cys48Ser)SPB showed a concentrationdependent in vitro activity, suggesting that it may form noncovalent dimers. Here (Cys48Ser)SPB isolated from bronchoalveolar lavage of transgenic mice was studied at different concentrations by circular dichroism (CD) spectroscopy, pulsating bubble surfactometry, mass spectrometry and reversedphase HPLC. The results indicate that (Cys48Ser)SPB, both in a phospholipid environment and in organic solvents, is largely monomeric and exhibits low activity at concentrations lower than 1 2 M, while at higher concentrations it forms noncovalent dimers, which are nearly functionally equivalent to native SPB in vitro. Furthermore, electrospray mass spectrometry showed that more dimers were found relative to the monomer when the polarity of the solvent was decreased, and when the concentration of SPB increased. (Cys48Ser)SPB also eluted earlier than native SPB in reversedphase HPLC. Taken together, these results indicate that a polar surface is buried upon dimerisation, thereby promoting formation of interchain ion pairs between Glu51 Arg52 and Glu51Arg52.

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Cell-specific and developmental regulation of rabbit surfactant protein B promoter in transgenic mice

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.2001.280.4.l724 ◽

2001 ◽

Vol 280 (4) ◽

pp. L724-L731 ◽

Cited By ~ 9

Author(s):

Constantin C. Adams ◽

M. Nurul Alam ◽

Barry C. Starcher ◽

Vijayakumar Boggaram

Keyword(s):

Transgenic Mice ◽

Developmental Regulation ◽

Surfactant Protein ◽

Developmental Expression ◽

Alveolar Type ◽

Clara Cells ◽

Specific Expression ◽

Surfactant Protein B ◽

Dna Elements ◽

Protein B

Surfactant protein B (SP-B) is expressed tissue specifically in the lung and is developmentally regulated. To identify genomic regions that control SP-B expression, we analyzed SP-B promoter activity in transgenic mice containing rabbit SP-B 5′-flanking DNA fragments linked to the chloramphenicol acetyltransferase (CAT) reporter gene. Results showed that whereas the −2,176/+39-bp fragment failed to express CAT, shorter fragments of −730/+39 and −236/+39 bp expressed CAT tissue specifically in the lung. Further deletion of 5′-flanking DNA to −136 bp resulted in no expression of CAT. Immunostaining demonstrated that both −730/+39- and −236/+39-bp regions expressed CAT specifically in alveolar type II and Clara cells. The −236/+39-bp region expressed CAT at a significantly lower level than the −730/+39-bp region. CAT expression in mice containing the −730/+39-bp region was detected in embryonic day 14 lung and attained maximum levels in day 18 lung, indicating that the developmental expression of CAT was similar to that of SP-B. These data show that the DNA elements necessary for cell type-specific expression are located within −236/+39 bp of the SP-B gene. Additionally, these data suggest that the −2,176/−730- and −730/−236-bp regions contain the DNA elements that repress and enhance SP-B gene transcription, respectively.

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