Damaged Keratin Filament Network Caused by KRT5 Mutations in Localized Recessive Epidermolysis Bullosa Simplex

Epidermolysis bullosa simplex (EBS) is a blistering dermatosis that is mostly caused by dominant mutations in KRT5 and KRT14. In this study, we investigated one patient with localized recessive EBS caused by novel homozygous c.1474T > C mutations in KRT5. Biochemical experiments showed a mutation-induced alteration in the keratin 5 structure, intraepidermal blisters, and collapsed keratin intermediate filaments, but no quantitative change at the protein levels and interaction between keratin 5 and keratin 14. Moreover, we found that MAPK signaling was inhibited, while desmosomal protein desmoglein 1 (DSG1) was upregulated upon KRT5 mutation. Inhibition of EGFR phosphorylation upregulated DSG1 levels in an in vitro model. Collectively, our findings suggest that this mutation leads to localized recessive EBS and that keratin 5 is involved in maintaining DSG1 via activating MAPK signaling.

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Functional analysis of keratin filament network formation indicates clinical severity of epidermolysis bullosa simplex

Journal of the European Academy of Dermatology and Venereology ◽

10.1111/jdv.16495 ◽

2020 ◽

Vol 34 (10) ◽

Author(s):

O. Ansai ◽

S. Shinkuma ◽

R. Hayashi ◽

K. Tomii ◽

T. Deguchi ◽

...

Keyword(s):

Functional Analysis ◽

Epidermolysis Bullosa ◽

Network Formation ◽

Clinical Severity ◽

Epidermolysis Bullosa Simplex ◽

Keratin Filament ◽

Filament Network

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Epidermolysis Bullosa Simplex (Dowling-Meara Type) Is a Genetic Disease Characterized by an Abnormal Keratin-Filament Network Involving Keratins K5 and K14

Journal of Investigative Dermatology ◽

10.1111/1523-1747.ep12491885 ◽

1991 ◽

Vol 97 (6) ◽

pp. 959-968 ◽

Cited By ~ 142

Author(s):

Akemi Ishida-Yamamoto ◽

John A McGrath ◽

Stephen J Chapman ◽

Iren M Leigh ◽

E Birgitte Lane ◽

...

Keyword(s):

Epidermolysis Bullosa ◽

Genetic Disease ◽

Epidermolysis Bullosa Simplex ◽

Keratin Filament ◽

Filament Network

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A function for keratins and a common thread among different types of epidermolysis bullosa simplex diseases.

The Journal of Cell Biology ◽

10.1083/jcb.115.6.1661 ◽

1991 ◽

Vol 115 (6) ◽

pp. 1661-1674 ◽

Cited By ~ 129

Author(s):

P A Coulombe ◽

M E Hutton ◽

R Vassar ◽

E Fuchs

Keyword(s):

Transgenic Mice ◽

Basal Cell ◽

Epidermolysis Bullosa ◽

Single Gene ◽

Basal Layer ◽

Structural Function ◽

Epidermolysis Bullosa Simplex ◽

Physical Trauma ◽

Keratin Filament ◽

Filament Network

Previously we demonstrated that transgenic mice expressing a mutant keratin in the basal layer of their stratified squamous epithelia exhibited a phenotype bearing resemblance to a subclass (Dowling Meara) of a heterogeneous group of human skin disorders known as epidermolysis bullosa simplex (EBS) (Vassar, R., P. A. Coulombe, L. Degenstein, K. Albers, E. Fuchs. 1991. Cell. 64:365-380.). The extent to which subtypes of EBS diseases might be genetically related is unknown, although they all exhibit skin blistering as a consequence of basal cell cytolysis. We have now examined transgenic mice expressing a range of keratin mutants which perturb keratin filament assembly to varying degrees. We have generated phenotypes which include most subtypes of EBS, demonstrating for the first time that at least in mice, these diseases can be generated by different mutations within a single gene. A strong correlation existed between the severity of the disease and the extent to which the keratin filament network was disrupted, implicating perturbations in keratin networks as an essential component of these diseases. Some keratin mutants elicited subtle perturbations, with no signs of the tonofilament clumping typical of Dowling-Meara EBS and our previous transgenic mice. Importantly, basal cell cytolysis still occurred, thereby uncoupling cytolysis from the generation of large, insoluble cytoplasmic protein aggregates. Moreover, cell rupture occurred in a narrowly defined subnuclear zone, and seemed to involve three factors: (a) filament perturbation, (b) the columnar shape of the basal cell, and (c) physical trauma. This work provides the best evidence to date for a structural function of a cytoplasmic intermediate filament network, namely to impart mechanical integrity to the cell in the context of its tissue.

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Silencing of Vangl2 attenuates the inflammation promoted by Wnt5a via MAPK and NF-κB pathway in chondrocytes

Journal of Orthopaedic Surgery and Research ◽

10.1186/s13018-021-02268-x ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Ke Zhang ◽

Zhuoying Li ◽

Yunyang Lu ◽

Linyi Xiang ◽

Jiadong Sun ◽

...

Keyword(s):

Western Blotting ◽

Planar Cell Polarity ◽

Type Ii Collagen ◽

Mapk Signaling ◽

Dependent Manner ◽

Inflammatory Microenvironment ◽

Functional Roles ◽

Protein Levels ◽

Oa Chondrocytes

Abstract Background The Wnt planar cell polarity (PCP) pathway is implicated in osteoarthritis (OA) both in animals and in humans. Van Gogh-like 2 (Vangl2) is a key PCP protein that is required for the orientation and alignment of chondrocytes in the growth plate. However, its functional roles in OA still remain undefined. Here, we explored the effects of Vangl2 on OA chondrocyte in vitro and further elucidated the molecular mechanism of silencing Vangl2 in Wnt5a-overexpressing OA chondrocytes. Methods Chondrocytes were treated with IL-1β (10 ng/mL) to simulate the inflammatory microenvironment of OA. The expression levels of Vangl2, Wnt5a, MMPs, and related proinflammatory cytokines were measured by RT-qPCR. Small interfering RNA (siRNA) of Vangl2 and the plasmid targeting Wnt5a were constructed and transfected into ATDC5 cells. Then, the functional roles of silencing Vangl2 in the OA chondrocytes were investigated by Western blotting, RT-qPCR, and immunocytochemistry (ICC). Transfected OA chondrocytes were subjected to Western blotting to analyze the relationship between Vangl2 and related signaling pathways. Results IL-1β induced the production of Vangl2, Wnt5a, and MMPs in a time-dependent manner and the significantly increased expression of Vangl2. Vangl2 silencing effectively suppressed the expression of MMP3, MMP9, MMP13, and IL-6 at both gene and protein levels and upregulated the expression of type II collagen and aggrecan. Moreover, knockdown of Vangl2 inhibited the phosphorylation of MAPK signaling molecules (P38, ERK, and JNK) and P65 in Wnt5a-overexpressing OA chondrocytes. Conclusions For the first time, we demonstrate that Vangl2 is involved in the OA process. Vangl2 silencing can notably alleviate OA progression in vitro by inhibiting the expression of MMPs and increasing the formation of the cartilage matrix and can inhibit the proinflammatory effects of Wnt5a via MAPK and NF-κB pathway. This study provides new insight into the mechanism of cartilage inflammation.

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