Dystrophic epidermolysis bullosa: quantitative proteomics approach to molecular mechanisms

• Applicants: Professor Dr. Jörn Dengjel; Privatdozent Dr. Alexander Nyström
• Subject Area: Dermatology ; Biochemistry
• Term: from 2012 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 219062131

• Final Report Year: 2020

Final Report Abstract

Dystrophic epidermolysis bullosa (DEB) is manifested by chronically fragile skin that becomes heavily fibrotic at exposed sites and establishes a microenvironment supportive of progression of metastatic cutaneous squamous cell carcinomas (cSCCs). DEB is caused by deficiency of the extracellular protein collagen VII, which assembles into large anchoring fibrils that are critical for firm epidermal-dermal cohesion. The genotype to phenotype correlation in DEB is weak, with affected individuals with the same mutation combinations showing disparate phenotypes. This indicates that factors outside the status of collagen VII heavily influence disease presentation and progression. Knowledge of such factors and mechanisms can be therapeutically exploited to provide symptom relief and decrease the severity of the disease. The aim of this collaborative project was to generate new knowledge about the molecular mechanisms dysregulated in DEB by identifying hitherto unknown proteins and genes involved in disease pathogenesis and phenotypic variability. We focused our work on cell-cell crosstalk, perturbed signal transduction and the role of inflammation in disease progression. By using complementary approaches from global to targeted analyses, in vitro as well as in vivo, our aim was to better understand clinical phenotypes in DEB and to link these phenotypes to molecular pathways, thus to establish an important prerequisite for the design of novel, causal molecular therapies. Using primary cells, we shed light onto dysregulated molecular mechanism in DEB, focusing on TGF-β signaling. Primary DEB keratinocytes facilitated fibrosis in DEB. Loss of collagen VII had extra- and intracellular consequences, resulting in keratinocyte-supported inflammatory processes and tissue destabilization. Mechanistic analysis of DEB fibroblasts demonstrated that latent TGF-β activation in DEB occurred through several mechanisms, including thrombospondin-1, RGD-binding integrins, matrix metalloproteinases and reactive oxygen species, which acted in concert, in a self-perpetuating feedback loop to progress fibrosis. We also identified several links between loss of collagen VII and altered immunity. Microenvironmental alterations increased bacterial challenges in DEB skin. Importantly, we identified collagen VII as member of the lymphoid extracellular matrix, its loss leading to an intrinsic innate immune dysfunction and perturbed defense against bacteria. Finally, we performed a detailed analysis of disease progression in DEB using a mouse model and highlighted that targeting of inflammatory immunity and stimulation of the renin-angiotensin system might be novel therapeutic approaches for treatment of injury- and inflammationinduced fibrosis.

Publications

• Analysis of the functional consequences of targeted exon deletion in COL7A1 reveals prospects for dystrophic epidermolysis bullosa therapy. Mol. Ther. 2016;24(7):1302–11
  Bornert O, Kühl T, Bremer J, van den Akker PC, Pasmooij AM, Nyström A.
  
• Collagen VII Half-Life at the Dermal-Epidermal Junction Zone: Implications for Mechanisms and Therapy of Genodermatoses. J. Invest. Dermatol. 2016;136(6):1116–23
  Kühl T, Mezger M, Hausser I, Guey LT, Handgretinger R, Bruckner-Tuderman L, et al.
  
• Combinatorial Omics Analysis Reveals Perturbed Lysosomal Homeostasis in Collagen VII-deficient Keratinocytes. Mol Cell Proteomics. 2018 Apr;17(4):565-579
  Thriene K, Grüning BA, Bornert O, Erxleben A, Leppert J, Athanasiou I, Weber E, Kiritsi D, Nyström A, Reinheckel T, Backofen R, Has C, Bruckner-Tuderman L, Dengjel J
  
• Identification of tissue damage, extracellular matrix remodeling and bacterial challenge as common mechanisms associated with high-risk cutaneous squamous cell carcinomas. Matrix Biol. 2018;66:1–21
  Föll MC, Fahrner M, Gretzmeier C, Thoma K, Biniossek ML, Kiritsi D, et al.
  
• Impaired lymphoid extracellular matrix impedes antibacterial immunity in epidermolysis bullosa. Proc. Natl. Acad. Sci. U.S.A. 2018;115(4):E705–14
  Nyström A, Bornert O, Kühl T, Gretzmeier C, Thriene K, Dengjel J, et al.
  
• Generation of rabbit polyclonal human and murine collagen VII monospecific antibodies: A useful tool for dystrophic epidermolysis bullosa therapy studies. Matrix Biology Plus. 2019;4:100017
  Bornert O, Kocher T, Gretzmeier C, Liemberger B, Hainzl S, Koller U, et al.
  
• Proteomic profiling of fibroblasts isolated from chronic wounds identifies disease-relevant signaling pathways. J. Invest. Dermatol. 2020; 140(11):2280-2290
  Berberich B, Thriene K, Gretzmeier C, Kühl T, Bayer H, Athanasiou I, Rafei-Shamsabadi DA, Bruckner-Tuderman L, Nyström A, Kiritsi D, Dengjel J
  
• F-β Activation in Recessive Dystrophic Epidermolysis Bullosa. J. Invest. Dermatol. 2021
  Akasaka E, Kleiser S, Sengle G, Bruckner-Tuderman L, Nyström A.
  
• QR-313, an antisense oligonucleotide, shows therapeutic efficacy for treatment of dominant and recessive dystrophic epidermolysis bullosa: a preclinical study. J. Invest. Dermatol. 2021
  Bornert O, Hogervorst M, Nauroy P, Bischof J, Swildens J, Athanasiou I, Tufa SF, Keene DR, Kiritsi D, Hainzl S, Murauer EM, Marinkovich MP, Platenburg G, Hausser I, Wally V, Ritsema T, Koller U, Haisma EM, Nyström A