ANCA-associated vasculitis and organ-on-chips disease model

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Ethelbert Hunter
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1 Vaskulitis-zentrum Süd Tübingen-Kirchheim ANCA-associated vasculitis and organ-on-chips disease model Elena Csernok Klinik für Innere Medizin, Rheumatologie und Immunologie Kreiskliniken Esslingen Klinik Kirchheim Akademisches Lehrkrankenhaus der Universität Tübingen

2 ANCA-associated-vasculitides necrotizing inflammation of the small vessels: vasculitis and granulomata Antineutrophil Cytoplasmic Antibodies

sinusitis, retroortbital mass otitis, swollen salivary glands bronchial stenosis pulmonary infiltrates, nodules glomerulonephritis myalgia, myositis arthralgia

(Germany) Prevalence 58/million (Germany) CHC -1992, 2012 -Definition granulomatous inflammation involving the respiratory tract necrotizing vasculitis affecting

3 sinusitis, retroortbital mass otitis, swollen salivary glands bronchial stenosis pulmonary infiltrates, nodules glomerulonephritis myalgia, myositis arthralgia leucocytoclastic vasculitis polyneuropathy intracerebral granulomas episcleritis subglottic stenosis Granulomatosis with polyangiitis Incidence 8-12 /million/year (Germany) Prevalence 58/million (Germany) CHC -1992, Definition granulomatous inflammation involving the respiratory tract necrotizing vasculitis affecting small to medium-sized vessels (e.g., capillaries, venules, arterioles, and arteries) necrotizing glomerulonephritis. C-/PR3-ANCA are closely associated with vasculitis

Pathogenesis of ANCA-associated vasculitis

initiating event, a final common pathway

4 Pathogenesis of ANCA-associated vasculitis complex interactions: Risk genes, enviromental factors, epigenetics, innate/adaptive immunity NETs Whatever the initiating event, a final common pathway of injury entails: leukocyte activation with degranulation, generation of toxic oxygen metabolites vascular necrosis with fibrinous insudation

5 Animal models of ANCA-associated vasculitis MPO-ANCA-associated vasculitis can be induced in various forms in susceptible rodents 1. these models have focused predominantly on kidney involvement 2. all models exhibit much milder disease than that seen in pts 3. the findings of experiments using MPO-ANCA can not be generalized to all AAV PR3-ANCA-associated disease in animals is much less advanced than MPO-ANCA-associated vasculitis: 1. differences between human and rodent PR3 (structure and expression) 2. pathogenesis of necrotizing granulomatous inflammation is not known

6 What is the value of human vs. animal models? The advantages of using the human organ-on-chip model include: 1. the ability to study different stages of the disease (vasculitis and granulomata) and the specific target organs (i.e., microvascular blood vessel endothelium- renal, lung) 2. to focus on the role of specific pathogenic factors (i.e., immune cells, ANCA, NETs) 3. to investigate the effect of disease specific drug targets by using molecular blocking agents

7 Pathogenesis of AAV: from NETs to disease networks Human model systems the mechanistic role of the diseaseassociated genes: HLA-gene variants, PR3 1-antitrypsin, and the contributions of environments factors (Staph.aureus, drugs) deciphering the role of autoantigens (PR3), ANCA and NETs autoimmune mechanisms that lead to generation of ANCA Schönemarck, Csernok, 2013, Nephrol Dial Transplant to develop novel therapeutic target: anti-nets therapy

CAP 18 LL37 LPS TLR4 activated platelets S.au, Str. pyog. Ps. aer., E. coli, Mycob. tbc., Candida alb.

8 Update on NETs (Neutrophil extracellular traps) NAPDH + 2O2 Granule content: HLE, BPI, PR3, MPO, LF Antimicrobial peptides: LL37 PTX3 Chromatin CGD catalases NADPH oxidases NAPD + + H + +2O 2 = H 2 O 2 Histones: hypercitrullinated PR3: 24kDa! CAP 18 LL37 LPS TLR4 activated platelets S.au, Str. pyog. Ps. aer., E. coli, Mycob. tbc., Candida alb. ANCA DNases PR3 Deposition in inflammed tissue Antimicrobial activity Entrapment of pathogens EC cell damage Kessenbrock et al., Nature Medicine, 2009

9 Deciphering the role of NETS in AAV microbe (S. aureus) Drugs (cocaine) ANCA NETs modified PR3 (citrullination?) cf DNA (ng/ml) WG gen (n=29) remission **p=0.007 active T cell polarisation T B cell activation Th1, Th2, Th17?, Treg PR3 ANCA? Lange, Csernok et al., 2015, submitted Kessenbrock et al., Nature Medicine, 2009

10 NETS as therapeutic target? Potential targets: extracellular DNA: degradation by nucleases PAD4: blocking by inhibitors NETs promote trombosis: DNAse treatment Fuchs et al., 2010, PNAS NADPH-oxidase: inhibition

11 Organ-on-chips disease model in AAV: promise and challenges Helps to dissect out the role of genetic/enviromental factors, the pathological basis of disease, and to understand the contribution of neutrophils (i.e., NETs), ANCA and their target antigens in mediating disease Offers the possibility to test the efficacy and efficiency of new drugs on pre-clinical trials on-chip Generation of human organ-on-chip that incorporates both PR3-ANCAassociated vasculitis and granuloma formation is the major challenge facing researchers over the next decade

Vasculitis local: systemic

Vasculitis local: systemic Vasculitis Inflammation of the vessel wall. Signs and symptoms: 1- local: according to the involved tissue 2- systemic:(fever, myalgia, arthralgias, and malaise) Pathogenesis 1- immune-mediated 2- infectious