Molecular biology and pathology of type VII collagen*

Uitto, Jouni; Chung-Honet, Linda C.; Christiano, Angela M.

doi:10.1111/j.1600-0625.1992.tb00065.x

Cited by 66 publications

(45 citation statements)

References 29 publications

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“…12,16 Previous studies have indicated that epidermal keratinocytes are the primary source of COL7 in developing human skin. 5,6 Thus, epidermal keratinocytes have been the main focus in the development of corrective gene therapies for DEB caused by COL7A1 mutations.…”

Section: Discussionmentioning

confidence: 99%

Keratinocyte-/Fibroblast-Targeted Rescue of Col7a1-Disrupted Mice and Generation of an Exact Dystrophic Epidermolysis Bullosa Model Using a Human COL7A1 Mutation

Ito

Sawamura

Goto

et al. 2009

The American Journal of Pathology

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Recessive dystrophic epidermolysis bullosa (RDEB) is a severe hereditary bullous disease caused by mutations in COL7A1, which encodes type VII collagen (COL7). Col7a1 knockout mice (COL7 m؊/؊ ) exhibit a severe RDEB phenotype and die within a few days after birth. Toward developing novel approaches for treating patients with RDEB, we attempted to rescue COL7 m؊/؊ mice by introducing human COL7A1 cDNA. We first generated transgenic mice that express human COL7A1 cDNA specifically in either epidermal keratinocytes or dermal fibroblasts. We then performed transgenic rescue experiments by crossing these transgenic mice with COL7 m؉/؊ heterozygous mice. Surprisingly, human COL7 expressed by keratinocytes or by fibroblasts was able to rescue all of the abnormal phenotypic manifestations of the COL7 m؊/؊ mice, indicating that fibroblasts as well as keratinocytes are potential targets for RDEB gene therapy. Furthermore, we generated transgenic mice with a premature termination codon expressing truncated COL7 protein and performed the same rescue experiments. Notably, the COL7 m؊/؊ mice rescued with the human COL7A1 allele were able to survive despite demonstrating clinical manifestations very similar to those of human RDEB, indicating that we were able to generate surviving animal models of RDEB with a mutated human COL7A1 gene. This model has great potential for future research into the pathomechanisms of dystrophic epidermolysis bullosa and the development of gene therapies for patients with dystrophic epidermolysis bullosa. Dystrophic epidermolysis bullosa (DEB) is clinically characterized by mucocutaneous blistering in response to minor trauma, followed by scarring and nail dystrophy. The blistering occurs along the epidermal basement membrane zone (BMZ) just beneath the lamina densa at the level of the anchoring fibrils. The inheritance of DEB can be autosomal dominant (DDEB) or autosomal recessive (RDEB), each comprising subtypes of different clinical presentations and severities.1 Both DDEB and RDEB are known to be caused by mutations in the COL7A1 gene encoding type VII collagen (COL7), the major component of anchoring fibrils.2 The most severe RDEB subtype, the Hallopeau-Siemens subtype, shows a complete lack of expression of type VII collagen, whereas a less severe RDEB subtype, the non-Hallopeau-Siemens subtype, shows some collagen expression. The clinical fea-

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Section: Discussionmentioning

confidence: 99%

Keratinocyte-/Fibroblast-Targeted Rescue of Col7a1-Disrupted Mice and Generation of an Exact Dystrophic Epidermolysis Bullosa Model Using a Human COL7A1 Mutation

Ito

Sawamura

Goto

et al. 2009

The American Journal of Pathology

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“…DEB has an autosomal dominant or recessive (RDEB) inheritance, the recessive forms being more severe. [1][2][3][4][5][6][7] Clinical RDEB ranges in severity from mild localized forms with limited blistering to the particularly severe, generalized form (RDEB-sev gen). Individuals with RDEB-sev gen suffer from lifelong severe skin and mucosal blistering followed by scarring, caused by lossof-adhesion between the epidermis and the dermis.…”

Section: Introductionmentioning

confidence: 99%

Immune reactivity to type VII collagen: implications for gene therapy of recessive dystrophic epidermolysis bullosa

et al. 2010

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Recessive dystrophic epidermolysis bullosa (RDEB) is a severe genodermatosis caused by loss-of-function mutations in COL7A1 encoding type VII collagen, the component of anchoring fibrils. As exogenous type VII collagen may elicit a deleterious immune response in RDEB patients during upcoming clinical trials of gene therapies or protein replacement therapies, we developed enzyme-linked immunosorbent assay (ELISA) and enzyme-linked immunosorbent spot (ELISPOT) assays to analyze B-and T-cell responses, to the full-length type VII collagen. The ELISA was highly sensitive and specific when tested against sera from 41 patients with epidermolysis bullosa acquisita (EBA), and the IFN-g ELI-SPOT detected a cellular response that correlated with ongoing EBA manifestations. Both tests were next applied to assess the risk of an immune response to type VII collagen in seven RDEB patients with a range of type VII collagen expression profiles. Immune responses against type VII collagen were dependent on the expression of type VII collagen protein, and consequently on the nature and position of the respective COL7A1 mutations. These immunologic tests will be helpful for the selection of RDEB patients for future clinical trials aiming at restoring type VII collagen expression, and in monitoring their immune response to type VII collagen after treatment.

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“…Type VII collagen (C7) 3 resides within the basement membrane zone beneath stratified squamous epithelium (1,2). C7 is a major component of anchoring fibrils, structures that attach the epidermal basement membrane of the skin to the underlying papillary dermis (3,4).…”

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confidence: 99%

Characterization of Molecular Mechanisms Underlying Mutations in Dystrophic Epidermolysis Bullosa Using Site-directed Mutagenesis

Woodley

Hou

Martín

et al. 2008

Journal of Biological Chemistry

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Type VII collagen (C7) is a major component of anchoring fibrils, structures that mediate epidermal-dermal adherence. Mutations in gene COL7A1 encoding for C7 cause dystrophic epidermolysis bullosa (DEB), a genetic mechano-bullous disease. The biological consequences of specific COL7A1 mutations and the molecular mechanisms leading to DEB clinical phenotypes are unknown. In an attempt to establish genotype-phenotype relationships, we generated four individual substitution mutations that have been associated with recessive DEB, G2049E, R2063W, G2569R, and G2575R, and purified the recombinant mutant proteins. All mutant proteins were synthesized and secreted as a 290-kDa mutant C7 ␣ chain at levels similar to wild type C7. The G2569R and G2575R glycine substitution mutations resulted in mutant C7 with increased sensitivity to protease degradation and decreased ability to form trimers. Limited proteolytic digestion of mutant G2049E and R2063W proteins yielded aberrant fragments and a triple helix with reduced stability. These two mutations next to the 39-amino acid helical interruption hinge region caused local destabilization of the triple-helix that exposed an additional highly sensitive proteolytic site within the region of the mutation. Our functional studies demonstrated that C7 is a potent pro-motility matrix for skin human keratinocyte migration and that this activity resides within the triple helical domain. Furthermore, G2049E and R2063W mutations reduced the ability of C7 to support fibroblast adhesion and keratinocyte migration. We conclude that known recessive DEB C7 mutations perturb critical functions of the C7 molecule and likely contribute to the clinical phenotypes of DEB patients.Type VII collagen (C7) 3 resides within the basement membrane zone beneath stratified squamous epithelium (1, 2). C7 is a major component of anchoring fibrils, structures that attach the epidermal basement membrane of the skin to the underlying papillary dermis (3, 4). In hereditary dystrophic epidermolysis bullosa (DEB), anchoring fibrils are diminutive and/or reduced in number (5-7). DEB is caused by mutations in the COL7A1 gene encoding C7 (8 -11).C7 is a homotrimer composed of three identical ␣ chains. Each ␣ chain has a 145-kDa central collagenous triple-helical segment characterized by repeating Gly-X-Y amino acid sequences. The helical central domain is flanked by a large 145-kDa amino-terminal, noncollagenous domain (NC1) and a small 34-kDa carboxyl-terminal non-collagenous domain (NC2) (4, 12). Within the papillary dermis, C7 molecules form antiparallel, tail-to-tail dimers stabilized by disulfide bonding through a small carboxyl-terminal NC2 overlap between two C7 molecules. A portion of the NC2 domain is then proteolytically removed (13,14). The antiparallel dimers then aggregate laterally to form anchoring fibrils which interact with microfibrils, collagen fibrils, and micro-thread-like fibers within the papillary dermis. These interactions are thought to secure the epidermis and its underlying basement membra...

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Molecular biology and pathology of type VII collagen*

Cited by 66 publications

References 29 publications

Keratinocyte-/Fibroblast-Targeted Rescue of Col7a1-Disrupted Mice and Generation of an Exact Dystrophic Epidermolysis Bullosa Model Using a Human COL7A1 Mutation

Keratinocyte-/Fibroblast-Targeted Rescue of Col7a1-Disrupted Mice and Generation of an Exact Dystrophic Epidermolysis Bullosa Model Using a Human COL7A1 Mutation

Immune reactivity to type VII collagen: implications for gene therapy of recessive dystrophic epidermolysis bullosa

Characterization of Molecular Mechanisms Underlying Mutations in Dystrophic Epidermolysis Bullosa Using Site-directed Mutagenesis

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