The group has a long standing interest in elucidating the biology of TNF ligands including development of tumor targeted death ligands, receptor selective agonists and antagonists for clinical use. Current projects focus on (neuro-) degenerative diseases and mesenchymal stem cell (MSC) propagation and differentiation for regenerative medicine. Experimental work is supported by mathematical modeling through joint research with systems scientists of the Stuttgart Research Center Systems Biology (SRCSB).
Improving cancer therapy through genetic engineering of death ligands
The concept of targeted TNF ligands:
Targeting dependent membrane presentation of death ligands induces efficient
receptor activation and prevents off-target systemic toxicity.
TNFR1 targeting to combat inflammation
Unraveling the anti-inflammatory and immune regulatory mode of action of ATROSAB (SELECT)
The project is placed in the field of inflammatory diseases, for which cytokines, TNF and other family members in particular, have been recognized as the driving pathological mediators. The development and use of antagonists of TNF has proven over the past ten years to be a great clinical and commercial success. There are presently five anti-TNF biologics on the market, with annual class sales of over US$16 billion. Remarkably, anti-TNFs will soon become the top-selling drug of any class (including small molecules), and have undoubtedly revolutionized the treatment of autoimmune diseases. However, the current anti-TNFs are first-generation drugs and their limitations have become apparent over years of clinical use. Aside from being effective in only a fraction of patients, their limitations most notably include a universal "black box" warning regarding increased risk of tuberculosis reactivation and other infections, as well as warnings regarding increased susceptibility to demyelinating disorders and lymphomas. The first generation of anti-TNF biologics were developed based on our limited understanding of TNF biology in the 1980s and early 1990s; for example, all approved anti-TNF biologics are essentially "me-too" drugs with respect to target specificity and selectivity. That is, they bind to both membrane and soluble forms of TNF, though notably, etanercept (a TNFR2 receptor), also binds to LT (Kaymakcalan et al. (2009) Clin Immunol 131, 308-316). Knowledge of the importance of TNF in both health and disease has grown in the last 20 years, leading to an understanding of what could constitute an optimal therapeutic profile for a TNF inhibitor, i.e. with improved safety and efficacy compared to the approved nonselective anti-TNFs. As a solution, selective inhibition of specific aspects of TNF signaling is the prevailing concept. Presently, different receptor-selective and nonfunctional mutants of TNF are exploited in preclinical models (Tansey, M.G. and Szymkowski, D.E. (2009) Drug Discov Today doi:10.1016/j.drudis.2009.10.002). As an alternative strategy, receptor-specific antagonistic antibodies suitable for clinical application are developed, based on earlier findings of the applicants that a monoclonal antibody, H398, serves as a universal inhibitor of TNFR1-mediated TNF responses (Thoma et al,., 1990, PMID: 2170559; Moosmayer et al,., 1995, PMID: 7553069). More recently, the humanization of H398 (Kontermann et al, 2008) and the subsequent generation of a humanized IgG1 of this human TNFR1-specific reagent (Zettlitz et al, 2010) in the applicants’ laboratory form the basis of this project.
The objective of this preclinical subproject is to support and complement the parallel clinical study (Phase 1), which exploits utility of selective TNFR1 targeting as an alternative to global inhibition of TNF. The aim of the subproject is a mechanistic understanding of the anti-inflammatory action of ATROSAB. In addition to an apparent direct beneficial effect on systemic inflammation through blockade of TNFR signaling of cells of the innate immune system, we will focus on the adaptive immune response and the T cell compartment, because here differences between global TNF blockers and receptor-selective interventions are to be expected. It is known from our earlier work that TNF acts as a costimulator during T cell activation, however, the specific role of TNF for individual T cell subsets, and the role of the two TNFRs in these responses, are barely understood. Our preliminary data suggest that in the presence of ATROSAB the in vitro generation of FoxP3+/CD4+ T cells increases in some patients with Morbus Crohn. Although the functional activity of these cells has not been studied so far, these data point to a positive role of ATROSAB in balancing the immune response. Therefore, with the studies outlined below, we will gain deeper knowledge about the cellular target of ATROSAB in the T cell compartment and its immunoregulatory potential with respect to modulation of T cell activation and its potential impact on the Treg system. Analyses of peripheral blood T cells from untreated, healthy donors as well as from participants of the phase 1 clinical trial before and after ATROSAB treatment will reveal immediate impacts on the T cell system with respect to subset distribution and functional activities. Further, through analyses of a specific transgenic mouse model, a huTNFR1 k/i line generated in a previous collaborative work of the PIs with U. Eisel, Groningen, in the context of the EU-FP6 “Neuropromise” consortium, we will learn about the in vivo efficacy of ATROSAB in models of chronic inflammatory diseases such as collagen-induced arthritis and EAE. Keeping in mind that a potential clinical target for selective TNFR intervention are neurodegenerative disorders, we will also use the transgenic mouse model to assess the activity of ATROSAB on different cell types of the brain, using in vitro treatment of primary cell cultures of neurons, astrocytes, microglia, and oligodendrocytes.
This is a joint project of the groups of Pfizenmaier, Scheurich and Kontermann of IZI with Baliopharm/Basel, funded by BMBF (innovative medicine program) (2012-2015).
MSC proliferation and differentiation
Controlled mesenchymal stem cell propagation and differentiation is an important goal in regenerative medicine. The interdisciplinary project aims at understanding the concerted action of mechanical, physical and biochemical signals through integration of
- quantitative experimental (HTS) methods
- material sciences
- advanced tissue engineering technologies
- mathematical modelling of signal networks
- continuum biomechanics
Generated knowledge will aid develop of biomimetic matrices and tissue engineering protocols for use in regenerative medicine