Project Details
Projekt
Deciphering the oxidation status of biomolecules in synovial fluids and tissues acting as damage associated molecular patterns (DAMPs) in rheumatoid arthritis
Subject Area
Rheumatology
Analytical Chemistry
Analytical Chemistry
Term
from 2014 to 2019
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 264172152
Arthritis, which can be due to degeneration or autoimmunity, is a major cause of disability and early retirement in the industrialized countries. For instance, more than 2 million German citizens were diagnosed to be markedly affected by cartilage degradation and/or loss of function of one or more joints. Thus, the socio-economic consequences and costs for health care are immense. Even worse, the incidence of the disease is continuously increasing.The excessive production of reactive oxygen species (ROS), such as hypochorus acid (HOCl) and hydroxyl radicals, is an important hallmark of inflammatory diseases, especially for rheumatoid arthritis (RA). These highly reactive species have the potential to modify nearly all biomolecules: effects towards proteins, glycosaminoglycans (the prime carbohydrates of the extracellular matrix of cartilage) and the (poly)unsaturated fatty acyl residues within phospholipids could be unequivocally substantiated. However, there is a considerable lack of knowledge about the products that are formed, for example, by oxidatively modified lipids (with reactive aldehyde groups) reacting with the amino groups of abundant proteins or glycosaminoglycans. Additionally, it is increasingly recognized that endogenous molecules modified by ROS (damage-associated molecular patterns; DAMPs) activate cellular receptors that are accompanied by increased inflammation. We hypothesize that these known but "non-studied" substances are particularly relevant for the pathogenesis of inflammatory diseases, i.e. that oxidized compounds are particularly relevant for the pathogenesis of inflammatory rheumatic diseases and are thus of diagnostic and therapeutic importance. We deal with these aspects on different levels of complexity. First, we will synthesize oxidized and chlorinated fatty acids and phospholipids. The detailed characterization of these products by high resolution chromatography, mass spectrometry and NMR spectroscopy is a very challenging task, as methods have to be first adapted to these molecules. Even more challenging will be the analysis of reaction products formed between oxidized fatty acids/lipids and glycosaminoglycans or peptides mimicking the active sites of proteins (lubricin, aggrecan) involved in rheumatic diseases. Second, oxidized molecule classes identified in the first aim will be investigated both in synovial fluid and extracts from the synovial membranes from patients suffering from rheumatic diseases in relation to the severity of the disease. Third, we will judge the relevance of identified oxidized PL, GAG, and proteins as oxidative DAMPs on the cellular immune response. For this task, their effects on T cells, antigen presenting cells and monocytes from the rheumatoid synovium will be studied in vitro by measuring typical inflammation markers such as interferon-gamma and selected cytokines that are released by the cells.
DFG Programme
Research Grants
