Laboratory of Molecular Biology

Team:

Gene Therapy of Genodermatoses; Head: Dr. habil. Julia Reichelt

Our research group is using designer nucleases to develop gene therapies for inherited keratinopathies. Currently, the focus is on heterozygous mutations in the keratin genes KRT10 causing epidermolytic ichthyosis (EI), KRT9 causing palmoplantar keratoderma (PPK), KRT5 and KRT14 both causing epidermolysis bullosa simplex (EBS).

Keratins are the most abundant proteins in the epidermis and essential for skin integrity. The molecules polymerise yia their central rod-shaped domains into filaments forming a cytoskeleton that spans the entire cytoplasm and provides cell stability. Mutant keratins integrate into the cytoskeleton and reduce its resilience towards stress. In the skin, this causes blister formation upon mild friction in patients with EBS and, after initial blistering in the first months of life, progressive hyperkeratosis in patients with EI (generalized) or PPK (restricted to palms and soles).

Until recently, inherited diseases were seen as incurable. With the invention of designer nuclease technology, that allows specific targeting and traceless repair of genetic mutations, effective treatments for genetic disorders such as genodermatoses becomes feasible.

Our gene therapy approach for keratinopathies aims to delete expression of the dominant-negative mutant keratin allele while leaving the wild-type allele intact. The latter is sufficient to form stable filaments and restore skin resilience. To this end, we are using CRISPR/Cas9 and TALEN to target and delete the mutant keratin genes in keratinocytes isolated from patients. Correctly targeted keratinocytes are expanded and further investigated. The goal is to identify keratinocyte clones which build resilient keratin filaments, lack any off-target effects from the nuclease treatment, and are capable of forming and sustaining regeneration of a functional epidermis over a life time when grafted onto the skin.

Team: o.Univ.Prof. Dr. med Matthias Schmuth, Thomas Trafoier, Dr. med, PhD student.

Dendritic cells and their role in allergy; Head: ao.Prof. Dr phil. Christine Heufler

Allergic immune reactions are mediated by T helper (Th)2 cells characterized by the production of specific cytokines like Interleukin 4 and Interleukin 13. Th2 cells arise from naïve Th0 cells in conditions still under investigation. There is ample evidence that DC are required to direct immune responses toward allergic Th2 differentiation after interaction with allergens. Specific mechanisms, however, are not known. With an in vitro system consisting of human monocyte derived dendritic cells and allogeneic naïve CD4+ Th0 cells we test the impact of allergenic and non-allergenic homologous proteins of the lipocalin family on the differentiation of helper T cells. Lipocalins include most major mammalian respiratory allergens. We identified the formyl peptide receptor (FPR) 3, located in endosomes of dendritic cells, to interact with break down products of allergenic lipocalins but not of their non-allergenic homologous. The consequence of this binding is a shut-off of IL12 production by dendritic cells and, thus, the induction of allergy-mediating Th2 cells. We are now testing the characteristics of the peptides capable of interaction with FPR3 and their effect on dendritic cells. Knowing the specific conditions of peptides interaction with FPR3 may open therapeutic options.

Team (April 2020): Dominik Klaver, MSc., PhD student; Susanne Neyer, technical assistance; Angela Romani, technical assistance