G551D Cystic Fibrosis Mice Exhibit Abnormal Regulation of Inflammation in Lungs and Macrophages

Abstract

The major cause of death in cystic fibrosis (CF) is chronic lung disease associated with persistent infection by the bacterium, Pseudomonas aeruginosa. S100A8, an S-100 calcium-binding protein with chemotactic activity, is constitutively expressed in the lungs and serum of CF patients. Levels of S100A8 mRNA were found to be three to four times higher in the lungs of mice carrying the G551D mutation in CF transmembrane conductance regulator compared with littermate controls. Intravenous injection of bacterial LPS induced S100A8 mRNA in the lung to a greater extent in G551D mice than in wild-type littermates. Localization of S100A8 mRNA and protein in the lung indicate that it is a marker for neutrophil accumulation. Bone marrow-derived macrophages from G551D mice were shown to also exhibit hypersensitivity to LPS, measured by induction of TNF-α. These results provide evidence that the pathology of CF relates to abnormal regulation of the immune system.

Transcriptional Adaptation to Cystic Fibrosis Transmembrane Conductance Regulator Deficiency

“…This family of peptides is expressed by various cell types and share potent chemoattractant activities, stimulating inflammatory cell trafficking. Increased expression of S100A8 (calgranulin A) was previously demonstrated in alveolar macrophages from CFTR mutant mice, the authors suggesting that increased S100A8 may contribute to the enhanced inflammatory responses seen in the absence of CFTR (22). Expression of S100A8 by alveolar macrophages was induced by TNF-␣, interferon ␥ and IL-1␤, mediated at least in part by AP-1-dependent pathways (20).…”

Novel Intra- and Inter-molecular Sulfinamide Bonds in S100A8 Produced by Hypochlorite Oxidation

“…Reflectron TOF-MS of Asp-N digest products indicated intense ions with m/z 1457.61, 2287.98, 2448.30 (Fig. 2D), identical to the protonated peptides A8 Ϫ2-12 , A8 [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] , and Met(O)-A8 . No peptide corresponding to A8 32-57 was evident, although there was an additional ion at m/z 3802.7562.…”

“…A8 and the chemotactic hinge region peptide (A8 [42][43][44][45][46][47][48][49][50][51][52][53][54][55] ) elicit sustained leukocyte recruitment in vivo with an early infiltrate of PMN (16) followed by mixed mononuclear cells (17). Similar to human, mA8 is associated with a number of acute and chronic inflammatory conditions including acute inflammation (18), bacterial infection (19), atherogenesis (17), delayed type hypersensitivity, and cystic fibrosis (20). Murine A8 is up-regulated by LPS (21), interferon ␥, and tumor necrosis factor in macrophages (22) and by LPS and interleukin 1 in microvascular endothelial cells (23).…”

Animal models of chronic lung infection with Pseudomonas aeruginosa: useful tools for cystic fibrosis studies

“…These include excessive inflammation in CFTR tm1Hgu mice (Zahm et al 1997), abnormal mucociliary clearance in the CFTR tm1Hgu (Zahm et al 1997) and CFTR tm1Unc mice (Cowley et al 1997), an increase in goblet cells with a decreased in volume of ASL in the nasal epithelium of CFTR tm1Unc mice (Tarran et al 2001), a more distal extension of submucosal glands in CFTR tm1Hgu and CFTR tm1G551D mice (Borthwick et al 1999), hypersensitivity of bone marrow-derived macrophages from CFTR tm1G551D mice to bacterial LPS (Thomas et al 2000), and abnormalities in intracellular nitric oxide syntethase expression in CFTR tm1Unc and CFTR tm1Kth mice (Kelley & Drumm 1998, Steagall et al 2000. Pulmonary abnormalities have been described in CFTR tm1Unc mice bred to congenicity using the C57BL/6 strain (Kent et al 1997).…”