The pathogenesis of Alport syndrome involves type IV collagen molecules containing the α3(IV) chain: Evidence from anti-GBM nephritis after renal transplantation

The incubation of lens capsules with glucose in vitro resulted in changes in the mechanical and thermal properties of type-IV collagen consistent with increased cross-linking. Differential scanning calorimetry (d.s.c.) of fresh lens capsules showed two major peaks at melting temperatures Tm 1 and Tm 2 at approx. 54 degrees C and 90 degrees C, which can be attributed to the denaturation of the triple helix and 7S domains respectively. Glycosylation of lens capsules in vitro for 24 weeks caused an increase in Tm 1 from 54 degrees C to 61 degrees C, while non-glycosylated, control incubated capsules increased to a Tm 1 of 57 degrees C. The higher temperature required to denature the type-IV collagen after incubation in vitro suggested increased intermolecular cross-linking. Glycosylated lens capsules were more brittle than fresh samples, breaking at a maximum strain of 36.8 +/- 1.8% compared with 75.6 +/- 6.3% for the fresh samples. The stress at maximum strain (or ‘strength’) was dramatically reduced from 12.0 to 4.7 N.mm.mg-1 after glycosylation in vitro. The increased constraints within the system leading to loss of strength and increased brittleness suggested not only the presence of more cross-links but a difference in the location of these cross-links compared with the natural lysyl-aldehyde-derived cross-links. The chemical nature of the fluorescent glucose-derived cross-link following glycosylation was determined as pentosidine, at a concentration of 1 pentosidine molecule per 600 collagen molecules after 24 weeks incubation. Pentosidine was also determined in the lens capsules obtained from uncontrolled diabetics at a level of about 1 per 100 collagen molecules. The concentration of these pentosidine cross-links is far too small to account for the observed changes in the thermal and mechanical properties following incubation in vitro, clearly indicating that another as yet undefined, but apparently more important cross-linking mechanism mediated by glucose is taking place.

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Inhibition of laminin self-assembly and interaction with type IV collagen by antibodies to the terminal domain of the long arm.

The Journal of Cell Biology ◽

10.1083/jcb.103.5.1689 ◽

1986 ◽

Vol 103 (5) ◽

pp. 1689-1697 ◽

Cited By ~ 44

Author(s):

A S Charonis ◽

E C Tsilibary ◽

T Saku ◽

H Furthmayr

Keyword(s):

Self Assembly ◽

Binding Sites ◽

Type Iv Collagen ◽

Specific Interaction ◽

Basement Membranes ◽

Complex Domain ◽

Peptide Fragment ◽

Type Iv ◽

Collagen Molecules

Laminin is a major glycoprotein of the basement membrane. Although its precise localization and orientation within this structure is unknown, it is presumably anchored to other macromolecules such as type IV collagen or proteoheparan sulfate. In vitro, laminin has the ability to self-assemble and to bind to type IV collagen molecules at distinct sites. To identify more precisely the domains of the complex, cross-shaped laminin molecule that are involved in these interactions, images of laminin-laminin dimers and laminin-type IV collagen complexes obtained by the rotary shadowing method were analyzed. We observed that the complex domain at the end of the long arm of laminin is predominantly involved in these interactions. By using Fab fragments of antibodies specific for a peptide fragment derived from this complex domain, it is shown that laminin self-assembly is inhibited in their presence, as measured by turbidity and by electron microscopy. In addition, these antibodies inhibit the specific interaction of laminin with type IV collagen. These data suggest that the complex domain at the end of the long arm of laminin contains binding sites of potential importance for the assembly of basement membranes.

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Quantitative analysis of type IV collagen subchains in the glomerular basement membrane of patients with Alport syndrome with confocal microscopy

Nephrology Dialysis Transplantation ◽

10.1093/ndt/gfl090 ◽

2006 ◽

Vol 21 (7) ◽

pp. 1838-1847 ◽

Cited By ~ 3

Author(s):

Jian Su ◽

Zhi-Hong Liu ◽

Cai-Hong Zeng ◽

Wei-Gong ◽

Hui-Ping Chen ◽

...

Keyword(s):

Quantitative Analysis ◽

Confocal Microscopy ◽

Basement Membrane ◽

Glomerular Basement Membrane ◽

Alport Syndrome ◽

Type Iv Collagen ◽

Type Iv

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Distribution of Type IV Collagen in the Cochlea in Alport Syndrome

Archives of Otolaryngology - Head and Neck Surgery ◽

10.1001/archotol.131.11.1007 ◽

2005 ◽

Vol 131 (11) ◽

pp. 1007 ◽

Cited By ~ 38

Author(s):

Andreas F. Zehnder ◽

Joe C. Adams ◽

Peter A. Santi ◽

Arthur G. Kristiansen ◽

Chitsuda Wacharasindhu ◽

...

Keyword(s):

Alport Syndrome ◽

Type Iv Collagen ◽

Type Iv

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Creation of X-linked Alport Syndrome Rat Model with Col4a5 Deficiency

10.1101/2021.04.13.439726 ◽

2021 ◽

Author(s):

Masumi Namba ◽

Tomoe Kobayashi ◽

Mayumi Kohno ◽

Takayuki Koyano ◽

Takuo Hirose ◽

...

Keyword(s):

Rat Model ◽

Alport Syndrome ◽

Type Iv Collagen ◽

Interstitial Fibrosis ◽

Human Kidney ◽

Pharmacological Therapy ◽

Renal Diseases ◽

Cell Hyperplasia ◽

Type Iv ◽

Mutant Rat

Alport syndrome is an inherited chronic human kidney disease, characterized by glomerular basement membrane abnormalities. This disease is caused by mutations in COL4A3, COL4A4, or COL4A5 gene. The knockout mice for Col4α3, Col4α4, and Col4α5 are developed and well characterized for the study of Alport syndrome. However, disease progression and effects of pharmacological therapy depend on the genetic variability. This model is reliable only to mice. Therefore in this study, we created a novel Alport syndrome rat model utilizing rGONAD technology. Col4α5 deficient rats showed hematuria, proteinuria, high levels of BUN, Cre, and then died at 18 to 28 weeks of age (Hemizygous mutant males). Histological and ultrastructural analyses displayed the abnormalities including parietal cell hyperplasia, mesangial sclerosis, and interstitial fibrosis. Then, we demonstrated that α3/α4/α5 (IV) and α5/α5/α6 (IV) chains of type IV collagen disrupted in the Col4α5 deficient rats. Moreover, immunofluorescence analyses revealed that some glomeruli of Col4α5 mutant rats were found to be disrupted from postnatal day 0. Thus, Col4α5 mutant rat is a reliable candidate for Alport syndrome model for underlying the mechanism of renal diseases and further identifying potential therapeutic targets for human renal diseases.

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