Research > Research Programs > Molecular Therapy of Genetic Dermatoses

Research program for molecular therapy of genetic dermatoses

Epidermolysis bullosa (EB) is a genetic dermatosis which is caused by mutations in the genes coding the structural proteins of the skin. If these structural proteins are affected qualitatively or quantitatively or are completely absent, the lightest mechanical loads lead to blistering on the skin and sometimes also on the mucous membranes.

Depending on the level of fissure formation, different sub-forms are distinguished. In the mildest form – EB simplex – it comes to a cytolysis of the basal keratinocytes caused by mutations in, for example, KRT5, KRT14 or PLEC. The junctional form – EB junctionalis – is characterised by the formation of a fissure in the area of lamina lucida and is caused mainly by mutations in COL17A1 or in the coding sequences for LAM-332. The dystrophic EB is characterised by the formation of a fissure in the area of lamina densa and is caused by mutations in COL7A1.

Photos (6): R. Hametner

Mission

Epidermolysis bullosa (EB) is a rare genetic skin disease characaterised by an inherent instability of the dermo-epidermal junction (DEJ, a.k.a basement membrane zone or BMZ), a complex multi-protein scaffold that maintains the adherence of the upper layer of the skin, the epidermis, to the underlying dermis. The instability is caused by mutations in the genes that encode various proteins key to this function of the DEJ. To date mutations in 21 genes have been associated with the different subtypes of EB. For patients, the result is tissue fragility, leading to blisters and erosions following even minor pressure, friction, or trauma that accompanies normal daily life.

Our research aims to deliver effective, evidence-based clinical strategies that will enhance the quality of life of our patients. These include therapies designed to target key pathobiological processes in EB and molecular diagnostic assays that will enable accurate assessment of disease status and facilitate informed decisions on treatment.

Foremost among our goals, is a cure. Ultimately, this entails the correction of the genetic defect responsible for the disease at the level of the genome and in every cell of the patient’s body. This represents a tremendous challenge. Nevertheless, we continue to make significant strides towards this goal with the implementation of current state-of-the art gene editing technologies and their continual optimization to our patients’ needs.

Additionally, while EB mainly manifests itself as an inherent fragility of the skin, the consequences for the patient can be systemic and far-reaching. For the most severe recessive dystrophic subtype of the disease (RDEB), the biggest complications are the non-healing wounds that are associated with itch and pain, and that represent a burden to both patient and caregiver, massively impacting their quality of life. Furthermore, chronic wounds subsequently develop into life-threatening squamous cell carcinoma, which represents the primary cause of premature death in these patients. We address this multifaceted challenge of wound healing and cancer by engaging in research aimed at uncovering underappreciated factors that contribute to wound chronicity, malignant transformation, and tumour progression, with the aim of leveraging this knowledge for diagnosis and therapy.

AG Koller

Designer nucleases as gene therapy tools for the future

Gene therapy represents the only option to correct the underlying genetic cause of monogenic hereditary diseases like epidermolysis bullosa (EB). Easy access to the skin additionally makes it an ideal target for gene therapeutic applications. Gene correction can be performed either outside (ex vivo) or inside (in vivo) the body. The former is favoured for safety reasons. In an ex vivo treatment, stem cells are isolated from skin biopsies obtained from the patient and the mutated gene is repaired in the laboratory. The corrected cells are then expanded to skin sheets, which are then transplanted onto affected areas of the patient’s body (see Figure). The classical gene replacement therapy, in which the mutated gene is not corrected but an exogenous healthy copy is provided, has already been successfully applied to 3 patients suffering from the junctional form of EB.

 

Adapted according to Koller U, JATROS Dermatologie & Plastische Chirurgie, 2020; 1: 20-1.


The discovery of bacterial nucleases capable of binding and cleaving distinct genomic sequences, has served as a springboard for the development of powerful gene editing technologies. The list of genetic disorders for which nuclease-based gene editing tools have been applied is rapidly growing. The first designer nucleases, the zinc-finger nucleases, were discovered in the 1990s. These were later replaced by TALENs („transcription activator-like effector nuclease“) and in 2012 by CRISPR („clustered regularly interspaced short palindromic repeats“) / Cas9 („CRISPR associated protein 9“), both of which exhibit higher specificity and efficiency. The fundamental strategy employed to correct disease-associated genetic mutations by these nucleases requires specific binding and cleavage of the DNA in close proximity to the mutation, subsequently triggering different cell-endogenous repair mechanisms that can be harnessed for gene correction. These include homology-recombination to achieve traceless gene repair, end-joining-mediated reframing of frameshift mutations, or disruption of dominant negative mutations as necessary to achieve expression of functional protein. Our group focuses on the continuous development of the CRISPR/Cas9 technology for the correction of various EB-associated genes, aimed at the establishment of ex vivo gene therapies for patients suffering from different EB subtypes.

 

Group leader:
PD Ulrich Koller, PhD

Team members:
Thomas Kocher, PhD
Stefan Hainzl, PhD
Johannes Bischof, PhD
Bernadette Liemberger, PhD

 

Team AG Koller

AG Pinon / Gruber

Tumors have been described as wounds that do not heal. This is particularly pertinent for patients suffering from the severe recessive dystrophic form of epidermolysis bullosa (RDEB), whose chronic wounds are highly prone to malignant transformation into life-threatening skin tumors.

Our research group strives to understand the stepwise process in the malignant transformation of chronic wounds in the context of RDEB, with the overarching aim of developing strategies that will enhance the quality of life of our patients. We have shown reduced microbial diversity in RDEB wounds concurrent with an increase in pathogenic bacterial species, with direct consequences on the induction of cell-endogenous mutagenic processes that contribute to tumorigenesis. The data underscore that effective wound management should include an antimicrobial component and is critically important if we want to lower cancer risk in patients. Therefore, we investigate substances with known wound healing and anti-neoplastic properties, which enables a rapid translation to clinical trials for patients, combine molecular and cell profiling techniques with functional assays in clinically relevant models to identify markers that can be leveraged for diagnosis and therapy, and develop strategies based on harnessing the immune system to fight cancer.

 

Group leaders:
Josefina Piñón Hofbauer, PhD
Christina Guttmann-Gruber, PhD

Team members:
Anna Kaufmann, MSc
Victoria Leb-Reichl, PhD
Birgit Tockner, PhD
Tobias Welponer, MD

AG Wally

Our group has a long-standing interest in the development of small molecule-based therapies that specifically target the biology of the disease. This necessitates understanding the relevant pathomechanisms underlying EB. While significant progress is being made in the genotypic characterization of epidermolysis bullosa (EB), there are gaps in terms of identifying non-genetic determinants of the highly variable clinical phenotypes observed. Importantly, such disease-modifying traits may also serve as therapeutic targets.

Bench-to-bedside research for EB simplex:

In the course of investigating the underlying signalling events that contribute to dominantly inherited EB simplex disease expression, we were able to develop an instructive model of the JNK stress pathway in EBS, and identified IL-1ß as a potential linchpin in the pathway that could be targeted by therapeutic interference. Based on pre-clinical data, wherein we confirmed the positive effect of IL-1ß inhibition on keratinocytes in vitro, we were able to repurpose and develop a new formulation of the small molecule diacerein for clinical use in EBS. Our topical diacerein ointment was confirmed to be effective in reducing blister numbers in a pilot and a phase II/III clinical study, and has now entered a worldwide multi-center phase III clinical trial.

miRNAs shaping recessive-dystrophic EB:

Currently, we focus on the role of epigenetics, particularly miRNAs, in EB pathophysiology and disease progression, with a special interest in understanding mechanisms associated with the highly aggressive nature of squamous cell carcinomas that develop in recessive-dystrophic EB patients. A long-term goal is the ability to modulate disease-relevant miRNA-mediated pathways, by either inhibiting or substituting distinct miRNAs, or regulating their expression levels, and thereby impacting tumor development and / or progression.



Development of an early-diagnostics tool for RDEB-SCCs:

Cutaneous squamous cell carcinomas (SCC) associated with the rare genodermatoses recessive dystrophic epidermolysis bullosa (RDEB) are the primary cause of early death in these patients. They usually arise within characteristic, long-standing and often strongly infected wounds by the third decade of life. Frequently, the detection of SCCs at an early stage is hindered by the fact that they are hardly distinguishable from the wound surrounding, however, early detection is a pre-requisite to prevent these SCCs from quick and uncontrolled spreading. We therefore aim at developing a novel early-diagnostics method to identify SCCs based on deregulated expression of miRNAs in RDEB patients.

Group leaders:
PD Verena Wally, PhD

Team members:
Thomas Lettner, PhD
Michael Ablinger, MSc
Monika Wimmer, MSc
Roland Zauner, MSc
Julia Illmer, Bakk. biol.
Matthias Brandlmaier, MD

Immunology

Induction of immunological tolerance

Dr. Iris Gratz (leave of absence), Dr. Victoria Reichl (on leave of absence since autumn 2013), Dr. Ana Sancho (on leave of absence since autumn 2013), Sophie Kitzmüller, MA

This project is important for persons who can not produce at all a certain protein in their skin due to null mutations of a single gene (e.g. missing Type 17 collagen in the case of junctional Epidermolysis bullosa, JEB). If gene therapy is performed on an affected person, as a result a new protein (Type 17 collagen) is produced in the skin of this patient. Thereby it can happen that the immune defence system of the affected person considers the new protein as a foreign body and as a danger. In this case, all cells that that successfully underwent gene-therapy are rejected and thus the gene therapy remains without any effect.

Objective:

The goal of this project is to prepare the immune system of the EB patient in such a way that after the successfully performed ex-vivo gene therapy the newly introduced, foreign protein is accepted and no defence reaction (rejection of the transplant) takes place.

Stand:

We have established a mouse model for the simulation of ex-vivo skin gene therapy in order to test the effectiveness of our approach for tolerance induction. The used transplant donors can produce the human Type 17 collagen in their skin. The recipient mice are treated correspondingly before the transplantation in order to prevent the rejection reaction to Type 17 collagen. On the basis of the pre-treatment, it is possible for us to increase the acceptance of the transplant also with respect to the new skin protein human collagen 17 from 0 per cent to 80 per cent.

Overview:

The results of this project serve as a base for the development of a specific pre-treatment of persons with Epidermolysis bullosa prior to performing ex-vivo skin gene therapy (targeted induction of immunological tolerance), in order to slow down very much or to prevent completely the action of the defence mechanisms of the body against the now functional protein.

Team and contact

Univ.-Prof. Dr. Johann Bauer, MBA
Research Program in Molecular Therapy of Genodermatose
Interim head

Phone: +43 57255-57838
Tel.: +43 57255-24600

Mail: joh.bauer@salk.at
Publications
Dr. Elisabeth Mayr
Research Program in Molecular Therapy of Genodermatose
Research Coordinator

Phone: +43 (0) 57255-82413
Mail: el.mayr@salk.at
Publications
Dr. Sigrid Arming
Research Program in Molecular Therapy of Genodermatose
Quality management

Phone: +43 (0) 57255-82414
Mail: s.arming@salk.at
Dr. Pamina Schlager
Research Program in Molecular Therapy of Genodermatose
Quality management

Phone: +43 (0) 57255-82414
Mail: p.schlager@salk.at
Publications
Mag. Alfred Klausegger
Research Program in Molecular Therapy of Genodermatose

Phone: +43 (0) 57255-58294
Mail: a.klausegger@salk.at
Publications
Michael Ablinger, MSc
Research Program in Molecular Therapy of Genodermatose
Research Associate

Phone: +43 (0)57255-82407
Mail: m.ablinger@salk.at
Publications
Dr. Christina Gruber
Research Program in Molecular Therapy of Genodermatose
Research Associate

Phone: +43 (0) 57255-82412
Mail: c.gruber@salk.at
Publications
Dr. Stefan Hainzl
Research Program in Molecular Therapy of Genodermatose
Research Associate

Phone: +43 (0) 57255-80932
Mail: s.hainzl@salk.at
Publications
Dr. Thomas Kocher
Research Program in Molecular Therapy of Genodermatose
Research Associate

Phone: +43 (0) 57255-80932
Mail: t.kocher@salk.at
Publications
Dr. Ulrich Koller
Research Program in Molecular Therapy of Genodermatose
Research Associate

Phone: +43 (0) 57255-80930
Mail: u.koller@salk.at
Publications
Dr. Eva Murauer
Research Program in Molecular Therapy of Genodermatose
Research Associate

Mail: e.murauer@salk.at
Publications
Dr. Josefina Pinon-Hofbauer
Research Program in Molecular Therapy of Genodermatose
Research Associate

Phone: +43 (0) 57255-82412
Mail: j.d.pinon@salk.at
Publications
Dr. Victoria Reichl
Research Program in Molecular Therapy of Genodermatose
Research Associate

Phone: +43 (0) 57255-82414
Mail: v.reichl@salk.at
Publications
Dr. Birgit Tockner
Research Program in Molecular Therapy of Genodermatose
Research Associate

Phone: +43 (0) 57255-82412
Mail: b.tockner@salk.at
Publications
Dr. Bernadette Liemberger
Research Program in Molecular Therapy of Genodermatose
Research Associate

Phone: +43 (0) 57255-80933
Mail: b.liemberger@salk.at
Publications
Dr. med. univ. Tobias Welponer Fries
Research Program in Molecular Therapy of Genodermatose
Ph.D. student

Phone: +43 (0) 57255-82412
Mail: tobias.welponer@alumni.pmu.ac.at
Publications
Dr. Johannes Bischof
Research Program in Molecular Therapy of Genodermatose
Research Associate

Phone: +43 (0) 57255-80931
Mail: j.bischof@salk.at
Roland Zauner, MSc
Research Program in Molecular Therapy of Genodermatose
Research Associate

Phone: +43 (0) 57255-82412
Mail: rolan.zauner@salk.at
Publications
Anna Kaufmann, MSc
Research Program in Molecular Therapy of Genodermatose
Research Associate

Phone: +43 (0) 57255-82412
Mail: an.kaufmann@salk.at
Publications
Monika Wimmer, MSc
Research Program in Molecular Therapy of Genodermatose
Research Associate

Phone: +43 (0) 57255-82412
Mail: mo.wimmer@salk.at
Publications
Dr. Thomas Lettner
Research Program in Molecular Therapy of Genodermatose
Research Associate

Phone: +43 (0) 57255-82414
Mail: t.lettner@salk.at
Publications
Dr. Verena Wally, Ph.D.
Research Program in Molecular Therapy of Genodermatose
Research Associate

Phone: +43 (0) 57255-82405
Mail: v.wally@salk.at
Publications