No description available.

No description available.

No description available.

Abstract Laminins are basement membrane glycoproteins consisting of three polypeptide chains α, β and γ. Until now 12 members of the protein family have been characterized and all isoforms have an αβγ chain composition, but they assemble in varying combinations of chain variants. The functional properties of laminins include cell adhesion, proliferation, differentiation, growth and migration. Laminin-5 has a chain composition of α3β3γ2 with the distribution mainly restricted to epithelial basement membranes, where its biological functions involve anchorage and locomotion of cells. The importance of this protein for the attachment of basal keratinocytes is clearly demonstrated by the fact that all genes encoding its chains have been shown to be mutated in the severe skin blistering disease Epidermolysis bullosa junctionalis. The present study focused on investigations of the role of the laminin-5 isoform and particularly its γ2 chain in cell adhesion and migration. The role of the short arm of the laminin γ2 chain in the process of epithelial cell attachment is to serve as a kind of a bridging molecule to the extracellular environment, because it does not have any cell binding activity by itself. It was also shown that the newly synthesized γ2 chain participates in the complex process of cell migration, probably as one of the first attachment components for moving cells. Thus, as a migration and differentiation-associated molecule, laminin-5 was considered a potential marker for detection of malignant processes where cell movement plays a role. Subsequently it was shown that the γ2 chain is expressed not only in a restricted manner in human epithelial tissues, but also in a number of human epithelium-derived cancers. In some carcinomas, expression of the γ2 chain appeared to be a characteristic of cancer cells with invasive properties. Examination of over 50 dysplasias and cervical tumors revealed that γ2 chain antibodies were able to distinguish between lesions with or without invasive capacity. This is the first systematic study of epithelial cancers where γ2 chain antibodies have been shown to be a useful marker in the histopathological diagnostics. In addition, this study showed in a mouse tumor model that the γ2 chain of laminin-5 has a potential for being of use for in vivo tumor imaging.

Abstract Type IV collagen is only found in basement membranes, where it is the major structural component, providing a framework for the binding of other basement membrane components and a substratum for cells. The type IV collagen molecule is triple-helical and composed of three a chains which exist as six distinct forms (α1 - α6). Abnormalities in this basement membrane collagen structure and function are connected to both inherited and acquired diseases. Alport syndrome is a hereditary kidney disease associated with extrarenal complications, such as sensorineural deafness and eye abnormalities. The disease is caused by mutations in the COL4A3, COL4A4 and COL4A5 genes, coding for the type IV collagen α3, α4 and α5 chain genes, respectively. About 85% of the Alport syndrome cases are X-linked dominant, caused by mutations in the COL4A5 gene. In order to develop a basis for automated mutation analysis of the COL4A5 gene, previously unknown intron sequences flanking exons 2 and 37 were determined. Intron sequences flanking the other 49 exons were expanded from 35 to 190, and additionally, two novel 9 bp exons (exons 41A and 41B) were characterized in the large intron 41. In addition to optimization of the PCR amplification and sequencing conditions for all 51 exons and exon flanking sequences, optimization for the 820 bp promoter region and for the two novel exons was performed as well. Mutations were found in 79 unrelated patients of the 107 studied. This gives a high mutation detection rate of almost 75% in comparison with 50%, at its best, in other extensive mutation analyses of the COL4A5 gene using SSCP analysis. None of the mutations involved the promoter region or exons 41A and 41B. Circulating antibodies against basement membrane components have been recognized in some autoimmune diseases. Goodpasture syndrome is a rare autoimmune disease characterized by progressive glomerulonephritis and pulmonary hemorrhage. The target of the antibodies in this disease has been shown to be the noncollagenous NC1 domain of type IV collagen α3 chain. For unknown reasons, a minority of Alport syndrome patients also develops antibodies against α3 and α5 chains after renal transplantation with manifestation of severe anti-GBM disease. In order to investigate the antibodies both in Goodpasture and Alport syndrome, the NC1 domains of all six type IV collagen chains were produced as recombinant proteins in bacterial and mammalian expression systems, and an ELISA method was developed for antibody detection. Antibodies were found in both syndromes, interestingly also in Alport syndrome patients without the anti-GBM disease. The results of this work have a significant clinical value by providing for the first time complete, effective DNA-based analysis of all exon/intron and promoter regions of the COL4A5 gene in Alport syndrome.

Indiana University-Purdue University Indianapolis (IUPUI) / Elaborate vascularization of the retina is crucial for the development and functioning of the eye. The proper patterning of astrocytes is a key event preceding retinal angiogenesis by providing guidance cues for endothelial cells, yet how this is regulated still remains obscure. The dual function of proteoglycans in both extracellular matrix (ECM) composition and cell signal transduction suggests their potential in the regulation of astrocyte migration. The current study demonstrated that non-cell-autonomous regulation by neuroretina cell surface proteoglycan is crucial for PDGF-A regulated astrocyte migration. Ablation of glycosaminoglycan side chains of proteoglycans in neuroretina led to impaired astrocyte migration, incomplete retinal angiogenesis, and hyaloid vessel persistence. This is followed by severe photoreceptor degeneration as a result of reactive gliosis, which cannot be rescued by constitutively activated Kras signaling. Notably, inner limiting membrane (ILM), the basement membrane of the retina, was breached in proteoglycan-deficient retinae prior to the formation of astrocytic network. Herein we propose that cell surface proteoglycans are essential for the initial assembly of ILM, and this cannot be compensated by secreted ECM proteoglycans. In support of this, after removal of ILM in retinal explant by Collagenase digestion, establishment of a new ILM can be achieved by incubation with exogenous laminin-supplemented Matrigel. This basement membrane reconstitution failed, however, in proteoglycan-deficient retinae or in wild type samples digested with a combination of Heparinase and ChABC in addition to Collagenase. Taken together, our study reveals a novel function of neuroretinal cell surface proteoglycans in the initial assembly of basement membrane which subsequently serves as a permissive substratum necessary for astrocyte migration.

Metastatic cancer cells invade and spread to other locations by disrupting the basement membrane (BM). The membrane plays a major role during the normal development of an organism as well. In order to understand the invasion mechanism it is important to know about the interactions occurring between the proteins of the BM during normal development. This study concentrates on isolating and identifying the major factors associated with collagen IV, a major component of BM, during the third instar larval development of Drosophila. Western blot and mass spectrometry analysis revealed that collagen IV associates with various growth factors, signaling molecules, and proteins that may play a role during the development of Drosophila. Co-localization and knockdown studies performed on a single protein found through mass spectrometry suggested a possible role of this protein in the development of Drosophila. Further analysis of this proteins’ function will provide new insights into its developmental role and its potential role in collagen IV transport.

The domestic dog, Canis lupus familiaris, plays many roles in the lives of humans. Additionally, the dog is recognized for its potential as a model for many human hereditary diseases. Thus, the genetics and genomics of the dog are being studied extensively in order to facilitate its use as a model, as well as to help the dog for its own sake. As part of this research effort, our laboratory has added type I markers (i.e., the acidic and basic keratins, c-kit, type I and IV collagens, and the gene encoding uromodulin) to the emerging map of the canine genome. The mapping of genes, particularly those in large gene families such as the collagens, is valuable because it rapidly increases the density of gene loci on the map and provides insight regarding conservation of synteny between the dog and other mammals. The major focus of work reported here is the genetics of X-linked Alport syndrome (XLAS), a terminal renal disease that affects the human and the dog. The disease results from mutations in COL4A5, a type IV collagen gene. Reported here are the 1) sequencing and mapping of the canine cDNA encoding uromodulin, 2) mapping of the type I and type IV collagen genes, 3) sequencing of the full-length cDNA of canine COL4A5, 4) identification of a 10 bp deletion in COL4A5, causative for XLAS in our colony of mixed breed dogs, 5) development of a genetic test for identification of affected and carrier dogs in the colony and 6) assessment of gene expression in the kidneys of normal and XLAS-dogs. This assessment was performed using a canine-specific oligonucleotide microarray. XLAS dogs demonstrated up-regulation of many genes involved in extracellular matrix reorganization, cell structure, and immune response, as expected in a glomerulopathy with tubulointerstitial nephritis. Trends were verified by quantitative RT-PCR. A review of the current status of canine genetics research, and current understanding of hereditary diseases in the dog, concludes this dissertation.

No description available.

The domestic dog, Canis lupus familiaris, plays many roles in the lives of humans. Additionally, the dog is recognized for its potential as a model for many human hereditary diseases. Thus, the genetics and genomics of the dog are being studied extensively in order to facilitate its use as a model, as well as to help the dog for its own sake. As part of this research effort, our laboratory has added type I markers (i.e., the acidic and basic keratins, c-kit, type I and IV collagens, and the gene encoding uromodulin) to the emerging map of the canine genome. The mapping of genes, particularly those in large gene families such as the collagens, is valuable because it rapidly increases the density of gene loci on the map and provides insight regarding conservation of synteny between the dog and other mammals. The major focus of work reported here is the genetics of X-linked Alport syndrome (XLAS), a terminal renal disease that affects the human and the dog. The disease results from mutations in COL4A5, a type IV collagen gene. Reported here are the 1) sequencing and mapping of the canine cDNA encoding uromodulin, 2) mapping of the type I and type IV collagen genes, 3) sequencing of the full-length cDNA of canine COL4A5, 4) identification of a 10 bp deletion in COL4A5, causative for XLAS in our colony of mixed breed dogs, 5) development of a genetic test for identification of affected and carrier dogs in the colony and 6) assessment of gene expression in the kidneys of normal and XLAS-dogs. This assessment was performed using a canine-specific oligonucleotide microarray. XLAS dogs demonstrated up-regulation of many genes involved in extracellular matrix reorganization, cell structure, and immune response, as expected in a glomerulopathy with tubulointerstitial nephritis. Trends were verified by quantitative RT-PCR. A review of the current status of canine genetics research, and current understanding of hereditary diseases in the dog, concludes this dissertation.