In a model of autosomally recessive Alport syndrome, mice that lack the ␣3 chain of collagen IV (Col4␣3 ؊/؊ ) develop progressive glomerular damage leading to renal failure. The proposed mechanism is that podocytes fail to synthesize normal glomerular basement membrane, so the collagen IV network is unstable and easily degraded. We used this model to study whether bone marrow (BM) transplantation can rectify this podocyte defect by correcting the deficiency in Col4␣3. Female C57BL/6 Col4␣3 ؊/؊ (-/-) mice were transplanted with whole BM from male wild-type (؉/؉) mice. Control female -/-mice received BM from male -/-littermates. Serum urea and creatinine levels were significantly lower in recipients of ؉/؉ BM compared with those of -/-BM 20 weeks post-transplant. Glomerular scarring and interstitial fibrosis were also significantly decreased. Donorderived cells were detected by in situ hybridization (ISH) for the Y chromosome, and fluorescence and confocal microscopy indicated that some showed an apparent podocyte phenotype in mice transplanted with ؉/؉ BM. Glomeruli of these mice showed small foci of staining for ␣3(IV) protein by immunofluorescence. ␣3(IV) mRNA was detectable by reverse transcription-polymerase chain reaction and ISH in some mice transplanted with ؉/؉ BM but not -/-BM. However, a single injection of mesenchymal stem cells from ؉/؉ mice to irradiated -/-recipients did not improve renal disease. Our data show that improved renal function in Col4␣3-/-mice results from BM transplantation from wildtype donors, and the mechanism by which this occurs may in part involve generation of podocytes without the gene defect.

Interstitial fibroblasts play a central role in kidney fibrosis. Their origin is debated, with recent data indicating a contribution of bone marrow (BM)-derived cells to the expanded population of interstitial cells after kidney damage in animals and humans. This study investigated whether these BM-derived cells would respond appropriately to a fibrotic drive by producing collagen. A transgenic mouse that expresses both luciferase and ␤-galactosidase reporter molecules under the control of a 17-kb promoter and enhancer element of the gene encoding the ␣2 chain of the collagen I was used. Male transgenic BM was transplanted into female wild-type C57BL/6 mice (n ‫؍‬ 14), and unilateral ureteric obstruction was performed later to induce renal fibrosis. In the obstructed kidney of the BM-chimeric female mice, a mean of 8.6% of smooth muscle actin-positive interstitial cells were Y chromosome positive. Increased collagen I mRNA in the obstructed kidney was detected by in situ hybridization. No luciferase activity was detected by enzyme assays in tissue homogenates of BM recipients, and very few luciferase mRNA transcripts were seen, mainly in tubular cells. ␤-Galactosidase activity was not a useful reporter molecule because it could not be distinguished from enhanced endogenous ␤-galactosidase activity in the obstructed kidney. These results indicate that BM-derived interstitial cells do not make a significant contribution to collagen I synthesis in the context of renal injury.

Experimental autoimmune glomerulonephritis (EAG), an animal model of Goodpasture's disease, can be induced in Wistar Kyoto (WKY) rats by immunization with either collagenase-solubilized rat glomerular basement membrane (GBM) or the recombinant NC1 domain of the ␣3 chain of type IV collagen [␣3(IV)NC1]. EAG is characterized by circulating and deposited anti-glomerular basement membrane antibodies, focal necrotizing glomerulonephritis with crescent formation, and glomerular infiltration by T cells and macrophages. Previous studies have demonstrated that oral administration of collagenasesolubilized GBM to WKY rats prevented the development of EAG. Nasal administration of specific autoantigens has been reported to be more effective than oral administration in other models of autoimmune disease. The main aim of this study was to investigate further the concept of mucosal tolerance in EAG by examining the effect of nasal administration of recombinant rat ␣3(IV)NC1. Groups of WKY rats with EAG, induced by immunization with recombinant rat ␣3(IV)NC1, were given ␣3(IV)NC1 nasally on 3 consecutive days before immunization, at total cumulative doses of 25, 100, or 250 g per rat. A dose-dependent effect was observed on the development of EAG. A dose of 25 g had no effect on disease; 100 g resulted in a moderate reduction in the severity of nephritis; and 250 g led to a marked reduction in circulating and deposited antibodies, albuminuria, severity of glomerular abnormalities, and numbers of glomerular CD8؉ T cells and macrophages. In addition, there was a reduction in the proliferative response of splenocytes from rats in the high dose group (250 g) to ␣3(IV)NC1 in vitro. The results from this study clearly demonstrate for the first time that mucosal tolerance in EAG can be induced by nasal administration of recombinant rat ␣3(IV)NC1 and that this approach is effective in the prevention of crescentic glomerulonephritis. Further work using new antigen-specific treatment strategies may provide a novel approach to the treatment of patients with anti-glomerular basement membrane disease.

Pulmonary fibrosis is a common feature of a large group of lung diseases. The molecular mechanisms underlying pulmonary fibrosis and the key macromolecules involved are not fully understood yet. In an effort to better understand aspects of pulmonary fibrosis, the established bleomycin injection model in mice was used and the focus of the present study was on integrin-linked kinase (ILK) expression. ILK is an intracellular protein involved in the regulation of integrin-mediated processes. In fibrosis, ILK has been examined in the kidney and in the liver where it mediates epithelial to mesenchymal transition (EMT) and hepatic stellate cell activation, respectively. However, information on ILK's involvement in lung fibrosis is missing. In order to examine ILK's role in pulmonary fibrosis, we used both an in vivo and an in vitro approach. In vivo, the bleomycin model was used in order to examine ILK's expression and localization in the fibrotic lung. In vitro, transforming growth factor-β1 was used to induce fibrotic characteristics and EMT in alveolar epithelial cells. ILK's role in alveolar EMT was studied by siRNA. Our results demonstrate that in the animal model used, ILK exhibits a decrease in expression at early stages of the fibrotic process and that a specific subset of fibroblasts is expressing ILK. The in vitro experiments suggested that ILK is not directly involved in E-cadherin downregulation and initiation of EMT (as is the case in renal fibrosis) but is involved in upregulation of vimentin. These results suggest that ILK is involved in lung fibrosis in a tissue-specific manner and raise the possibility to use it as a specific therapeutic target for lung fibrosis in the future.