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) is a member of the collectin subfamily of C-type lectins, pattern recognition proteins participating in the innate immune response. Gene-targeted mice deficient in SP-D develop abnormalities in surfactant homeostasis, hyperplasia of alveolar epithelial type II cells, and emphysema-like pathology. Granulocyte/macrophage colony-stimulating factor (GM-CSF) is required for terminal differentiation and subsequent activation of alveolar macrophages, including the expression of matrix metalloproteinases and reactive oxygen species, factors thought to contribute to lung remodeling. Type II cells also express the GM-CSF receptor. Thus we hypothesized GM-CSF might mediate some or all of the cellular and structural abnormalities in the lungs of SP-D-deficient mice. To test this, SP-D (DϪGϩ) and GM-CSF (DϩGϪ) single knockout mice as well as double knockout mice deficient for both SP-D and GM-CSF (DϪGϪ) were analyzed by design-based stereology. Compared with wild type, DϪGϩ as well as DϩGϪ mice showed decreased alveolar numbers, increased alveolar sizes, and decreased alveolar epithelial surface areas. These emphysema-like changes were present to a greater extent in DϪGϪ mice. DϪGϩ mice developed type II cell hyperplasia and hypertrophy with increased intracellular surfactant pools, whereas DϩGϪ mice had smaller type II cells with decreased intracellular surfactant pools. In contrast to the emphysematous changes, the type II cell alterations were mostly corrected in DϪGϪ mice. These results indicate that GM-CSF-dependent macrophage activity is not necessary for emphysema development in SP-D-deficient mice, but that type II cell metabolism and proliferation are, either directly or indirectly, regulated by GM-CSF in this model. (6), an appropriate stereological analysis quantifying alterations in the number and size of type II cells and lamellar bodies has not been performed. SP-D-deficient mice also develop emphysema-like lesions with increased expression of matrix metalloproteinases (MMPs) (41) and increased production of reactive oxygen species (ROS) (45) and reactive nitrogen species (RNS) (2), suggesting an ongoing inflammatory process probably mediated by alveolar macrophages leads to destructive lung remodeling.Granulocyte/macrophage colony-stimulating factor (GM-CSF) is a cytokine released by various cell types in response to inflammatory stimuli. Alveolar type II cells and alveolar macrophages express GM-CSF and both subunits of the GM-CSF receptor, and genetic experiments suggest a role for GM-CSF in the function of both these cell types (see Refs. 12,33,38, and 39 for review). Overexpression of GM-CSF in mice causes type II cell hyperplasia and an increase in the number of alveolar macrophages (20). Mice deficient in GM-CSF develop lung alterations reminiscent of pulmonary alveolar proteinosis with decreased surfactant clearance due to a block in surfactant degradation by alveolar macrophages (10,22,36,44), but specific changes in lung structure have not been described. GM-CSF-deficient mice show an increased sus...

ABSTRACT:The pathogenesis of congenital cystic adenomatoid malformation (CCAM) is unknown and its natural history is unpredictable. Fatty acid binding protein-7 (FABP-7) has been previously described in brain and breast development, but never before in the lung. We investigate gene expression in CCAM, and hypothesize that CCAM results from an aberration in the signaling pathway during lung development. Under IRB approval, tissue specimens of fetal CCAM, fetal control, postnatal CCAM, and postnatal control were examined and microarray analysis was performed. Candidate differentially expressed genes were selected with log-odds ratio (B) Ͼ0 and false discovery rate Ͻ0.05. Validation of differential expression was achieved at the RNA and protein levels. FABP-7 was underexpressed in fetal CCAM compared with fetal lung in both the microarray and by RT-PCR. Findings were duplicated by Western Blot analysis and immunohistochemistry. This is the first description of FABP-7 in the human lung. Decreased expression of FABP-7 in fetal CCAM compared with normal fetal lung at both the RNA and protein levels suggests FABP-7 may have a role in pulmonary development and in the pathogenesis of CCAM. (Pediatr Res 64: 11-16, 2008) C ongenital cystic adenomatoid malformation (CCAM) is a multicystic pulmonary mass characterized by an abnormal proliferation of tissue resembling terminal respiratory bronchioles. The relatively rare lesions usually occur unilaterally and involve only one lobe of the lung. Diagnosis is often made by prenatal ultrasonography.CCAM has a variable natural history. Some lesions regress in utero with no residual abnormality at birth (1-2), others are associated with fetal polyhydramnios, mediastinal shift, and nonimmune hydrops fetalis resulting in the risk of fetal demise (3). Mediastinal shift and hydrops fetalis are indications for fetal intervention.Stocker et al.'s original classification of CCAM included three subtypes based predominantly on the cyst size. Type I lesions are composed of single or multiple large cysts (Ͼ2 cm in diameter); type II lesions are multiple, smaller cysts (Ͻ1 cm in diameter); and type III are more solid, microcystic lesions. Two variants were later added to the original classification system: type 0, composed of bronchial-like histology and type IV, a more distal acinar lesion (4).The pathogenesis of CCAM is unclear. Its original description was that of a hamartomatous lesion. The five Stocker CCAM types have also been described as each being distinct malformations, with unique etiologies resulting from a localized obstruction or atresia (2). The parenchymal maldevelopment characterizing CCAM has been associated with bronchial atresia (5). The bronchial atresia may result from a localized arrest in the bronchial tree during the branching phase of lung development, the pseudoglandular phase.Lung development during the pseudoglandular phase involves extensive epithelial-mesenchymal interaction of growth factors, transcription factors, and signaling molecules. Previous studies evalu...

We predict that it may be possible to improve pig disease resistance to Salmonella infection by studying genes that control a piglet's initial immune response. The NRAMP1 gene controls susceptibility to multiple pathogens and acts within the macrophage. The BPI gene encodes a neutrophil protein with inhibitory/killing functions against multiple gram-negative bacteria. We investigated NRAMP1 and BPI as candidate genes for contributing to resistance in Salmonella choleraesuis (SC) challenge in pigs. Five NRAMP1 sequence differences (polymorphisms, SNPs) were found, while we cloned and sequenced the full-length BPI gene and identified four polymorphisms at BPI. The effects these polymorphisms have on resistance to infection were tested in two experimental disease studies. In study 1, results showed NRAMP1 and BPI genotypes were associated with decreased fecal bacterial load during infection (P values: < .0006 to < .06). Immune cell numbers were also associated with BPI genotypes. In the second study, many additional immune traits and spleen and liver bacterial counts were collected. The NRAMP1 genotypes were associated with bacterial count in liver (P < .05 and P < .0006) and with polymorphonuclear phagocytes (P values from < .003 to < .05). The BPI genotypes were significantly associated with bacteria uptake by immune cells and with bacterial counts in liver (P<.1) and lymphocyte response post-challenge (P<.0001). These data indicate NRAMP1 and/or BPI gene variation may control, in part, response to Salmonella infection in pigs, and that these differences could be used to identify resistant animals.

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