Evaluation of muscarinic acetylcholine receptors type 3 in the pathogenesis of chronic inflammatory cholangiopathies
Final Report Abstract
Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are rare, chronic inflammatory diseases of the bile ducts whose pathogenesis involves genetic, environmental and autoimmune factors. Both diseases are serious autoimmune diseases that cause inflammation of the bile ducts and can ultimately lead to liver cirrhosis. Autoantibodies against the muscarinic acetylcholine receptor type 3 (mAChR3) may play a role in the pathogenesis. In cholangiocytes, mAChR3 regulates bicarbonate secretion into the bile ducts, which protects the bile duct cells from bile acid toxicity. Blockade of this mechanism by autoantibodies could contribute to chronic inflammation by reducing the protective alkaline environment. The aim of the project was to investigate the role of mAChR3 in the pathogenesis of these diseases. Functional mAChR3 autoantibodies were detected in the serum of patients with both diseases. PBC patients with mAChR3-inhibiting (mAChR3inh+) autoantibodies showed significantly higher levels of alkaline phosphatase and bilirubin, clinical markers for risk stratification associated with severe disease. In PSC patients, differences in the prevalence of mAChR3 autoantibodies were found in relation to the site of bile duct damage. Another focus of the work was the isolation of mAChR3-binding memory B cells from the peripheral blood of PBC and PSC patients. Using fluorescently labeled mAChR3 peptides, these specific B cells could be detected and isolated as single cells. Patients with PBC showed a significantly higher number of mAChR3-binding memory B cells compared to PSC patients. This indicates differences in the immune responses of the two diseases, which should be investigated further. The isolation of memory B cells as single cells allowed the antibody repertoire to be characterized at the molecular level by single cell sequencing. The V(D)J recombination of the antibody genes was analyzed in order to draw conclusions about the somatic hypermutation and affinity maturation of the antibodies. The results show that the majority of mAChR3-binding antibodies have germline-like properties, indicating an early maturation state. However, some antibodies also showed strong mutations indicating longlasting antigen exposure. To evaluate the functional effects of the autoantibodies, the mAChR3-binding antibodies were recombinantly monoclonally expressed in vitro. A total of 34 functional monoclonal antibodies were produced, of which one showed inhibitory and four activating effects on mAChR3 function. The functionality of mAChR3 antibodies and their influence on immune cells was also investigated. Overall, a reduced production of proinflammatory cytokines by mAChR3 was found. These results underline the importance of autoantibodies in the signal modulation of the muscarinic receptor and could provide information about possible therapeutic target structures.
Publications
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Evaluation of muscarinic acetylcholine receptor type 3 gene polymorphisms in patients with primary biliary cholangitis and primary sclerosing cholangitis. Hepatology Research, 50(3), 321-329.
Greverath, Lena Maria; Leicht, Elise; Wald de Chamorro, Nina; Wilde, Anne‐Christin Beatrice; Steinhagen, Lara Marleen; Lieb, Charlotte; Schmelzle, Moritz; Chopra, Sascha; Shibolet, Oren; Fischer, Janett; Berg, Thomas; Tacke, Frank & Müller, Tobias
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Antibodies to the Muscarinic Acetylcholine Receptor M3 in Primary Biliary Cholangitis Inhibit Receptor Function on Cholangiocytes. Frontiers in Immunology, 11.
Mayer, Christian; Preuss, Beate; Grottenthaler, Julia; Berg, Christoph & Klein, Reinhild
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Real-World Clinical Management of Patients with Primary Biliary Cholangitis—A Retrospective Multicenter Study from Germany. Journal of Clinical Medicine, 10(5), 1061.
Wilde, Anne-Christin Beatrice; Lieb, Charlotte; Leicht, Elise; Greverath, Lena Maria; Steinhagen, Lara Marleen; Wald de Chamorro, Nina; Petersen, Jörg; Hofmann, Wolf Peter; Hinrichsen, Holger; Heyne, Renate; Berg, Thomas; Naumann, Uwe; Schwenzer, Jeannette; Vermehren, Johannes; Geier, Andreas; Tacke, Frank & Müller, Tobias
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Evaluation of Inhibitory Antibodies against the Muscarinic Acetylcholine Receptor Type 3 in Patients with Primary Biliary Cholangitis and Primary Sclerosing Cholangitis. Journal of Clinical Medicine, 11(3), 681.
Wilde, Anne-Christin Beatrice; Greverath, Lena Maria; Steinhagen, Lara Marleen; de Chamorro, Nina Wald; Leicht, Elise; Fischer, Janett; Herta, Toni; Berg, Thomas; Preuss, Beate; Klein, Reinhild; Tacke, Frank & Müller, Tobias
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AASLD Foundation Abstract Award category “Early carreer investigator award in basic science” “Characterization of the antibody repertoire against mAChR3 in patients with PBC and PSC”
Anne Olbrich, Asis Mousa, Madlen Oelsner, Danilo Deichsel, Toni Herta, Madlen Matz-Soja, Ulrike Preuß, Reinhild Klein, Tobias Müller, Barbara Malik, Julia Benckert & Thomas Berg
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Sub-optimal therapy of patients with primary biliary cholangitis (PBC) in the real-life stetting of the German PBC cohort. Zeitschrift für Gastroenterologie, 62(11), 1931-1942.
Wiegand, Johannes; Franke, Annegret; Müller, Tobias; Stein, Kerstin; Bantel, Heike; Günther, Rainer; Denk, Gerald; Reuken, Philipp A.; Schattenberg, Jörn M.; Naumann, Uwe; Böttler, Tobias; Weber, Andreas; Zeuzem, Stefan; Hinz, Matthias; Greinert, Robin; Berg, Christoph; Wissniowski, Thaddäus Till; Simon, Karl-Georg; Trebicka, Jonel ... & Berg, Thomas
