Aptamers and tolerogenic protein complexes

The »Aptamers/Tolerogenic Protein Complexes« platform aims to create cross-institutional structures and networks for the research and further development of MHCII-glycopeptide complexes for the treatment of rheumatoid arthritis (RA) and of aptamers for use in the early detection of glycosylation defects in autoimmune diseases or their precursors.

Treatment options needed for durable disease control

For (auto)immune-mediated diseases such as RA, there is a great need for new treatment options. Available treatment options such as cytokine blockers rarely achieve remission or even cure of the disease. At the same time, these diseases are often diagnosed only after manifestation of sometimes irreversible damage. There is therefore a great need for new methods of early detection and treatment options to permanently control the disease-sustaining autoimmunity.

Preliminary work

In extensive preliminary work, a recombinant complex consisting of the MHC II (DRA / DRB1 * 0401) molecule and a galactosylated collagen II peptide has already been developed as an antirheumatic active substance and its immunoregulatory potential has been demonstrated in a large number of preclinical data. At the same time, methods for glycan isolation and the synthesis of biotinylated glycan structures were established, which can be used for the selection of aptamers.

Optimization of the formulation and glycosylation of MHC-II complexes

The main objectives of the project are to optimize the formulation and glycosylation of the MHC-II glycopeptide complexes, to study them in a humanized mouse model of RA, and to identify aptamers for the development of a detection system for glycosylation changes.

© Fraunhofer ITMP | Harald Burkhardt - modified from: Yang et al, Mol TherNucleic Acids. 2018; 13: Nucleic Acids 13:164-174 using SMART Medical images https://smart.servier.com
Oligonucleoitides can form a large variety of 3-dimensional structures in a sequence-dependent manner as potential ligands of functionally relevant biomolecules such as messengers of cell communication in the extracellular space or receptors on the surface of immune cells. From large oligonucleotide banks, these so-called apatamers can be specifically selected for high binding affinities for distinct biologically relevant target structures with the aim of developing diagnostic test methods but also identifying lead structures for therapeutic drug development.

Improving the treatment of rheumatoid arthritis

The development of a completely new class of compounds to reconstitute immunological self-tolerance by inducing regulatory lymphocyte populations can significantly improve the treatment of patients with RA. The work in the therapeutic platform provides the basis for preclinical demonstration of the efficacy of these molecules in a humanized mouse model. An aptamer-based detection system for the identification and quantification of glycosylation defects could lay the foundation for novel diagnostics for the early detection and tracking of immune diseases.

Bringing together complementary competencies

The platform »Aptamers/Tolerogenic Protein Complexes« combines the expertise of the Fraunhofer ITMP in the field of rheumatological diseases and their preclinical models with the experience of the Fraunhofer IGB and the Fraunhofer ITEM-R in the characterization of immune cells by means of bulk or single cell RNA sequence analysis, the expertise of the IZI-BB in the generation, synthesis and functionalization of aptamers, established procedures at the Fraunhofer IAP for the isolation as well as for the synthetic and semi-synthetic production of glycan targets

Outlook

After completion of the preclinical studies demonstrating the efficacy of the prototypical recombinant immunomodulatory HLADR4/CII peptide complex in the established humanized murine arthritis model of collagen II (CII) induced arthritis (CIA), the establishment of a GMP-compliant manufacturing process as well as the preclinical toxicity studies in preparation for the clinical phase 1b studies of the innovative compound for the therapy of rheumatoid arthritis are pending. The CII T cell receptor specific aptamers selected through collaboration on the project platform will be further developed into assays for the immune monitorinjg of cellular CII autoimmunity in peripheral blood for clinical applications. Similarly, following the successful identification of apatamers with specificity for post-translationally modified immunoglobulin structures as well as for metabolites of congenital glycosylation defects will be developed into optimized analytical assay systems in the service of improved clinical laboratory diagnostics.

The experience gained in the ongoing projects will be used to open up new applications of aptamer technology, in particular for the selective modulation of receptors of the immune system. To this end, further research is needed in target identification and drug design, particularly in the area of optimization of pharmacokinetic properties.