David Launay
Axes de recherche
Humoral Immunity and Systemic Sclerosis : role of B cells
Systemic sclerosis (SSc) is a severe chronic immune-mediated inflammatory disease characterized by widespread fibrosis of the skin and organs in a context of immune alterations and vascular dysfunction. Chronic inflammation and immune cell dysfunction are thought to have a central role in the pathophysiology of the disease. Among the various immune cel s, B lymphocytes are key players in SSc (as recently reviewed by our group), in view of altered B cell homeostasis and function both in patients and in murine models, the presence of specific autoantibodies, the possi- ble direct profibrotic role of B cells, and the efficacy of anti-B targeted therapy. Our project is to
(i) establish how B cells influence the aberrant fibrogenesis observed in SSc and (ii) characterize the interaction between memory T cells and B cells, with a focus on autoantibodies and T follicular helper (TFH) cells. We will rely on the unique opportunities for the recruitment of patients with SSc in the national and European reference center in Lille (http://reconnet.ern-net.eu/, http://www.fai2r.org/les-centres-fai 2r/centres-de-reference-fai2r/crmr-nord-nord-ouest-site-coordonnateur).
(ii). assess the mechanisms and consequences of interaction between B cells and fibroblasts. B cells will be counted in the skin of patients with SSc and animal models. Transcriptomic and proteomic approaches will be used to assess phenotypic and functional modifications of circulating and skin B cells in patients and in animal models of SSc. Fibroblasts (ATCC cell line and primary cultures, both in patients a d in murine models of HOCl-induced SSc 30 and cGvHD) will be co-cultured with resting or activated B cells isolated from the blood and skin of patients and controls. Two dimensional (2D) co-cultures will be primarily studied. Spheroids (collaboration with S Le Gac at the University of Twente) and organoids (WP1) are also planned for 3D co-culture of B cells and fibroblasts in the presence or absence of epitelial or endothelial cells. Proteomic and transcriptomic ap- proaches will assess the biological consequences of co-culture on fibroblasts and B cells, especially with regard to signaling pathways (a collaboration with C Rolando at USR 3290 36. Cytokine-blocking strategies (targeting IL-1, IL-6, TGFß and TNF-a), the role of BAFF and integrin/GARP, the presence or absence of contact (Transwell assays), and epithelial/endothelial mesenchymal transition will be evaluated in order to understand the interactions between B cells and fibroblasts. We shall focus on pro-inflammatory and pro-fibrotic profiles of B cells and fibroblasts.
Origin and role of autoantibodies
We will focus on autoantibodies against known autoantigens (mainly topoisomerase 1 and TIF1g) and suspected new antigenic targets detected with an immunoproteomics approach. We will identify possible pathogenic roles of these autoantibodies via co-cultures with fibroblasts. By way of an example, the antibodies against TIF1g observed in patients with paraneoplastic SSc will be extensively studied (I-SITE ULNE Expand, grant obtained). We will determine whether (i) the accumulation of unfolded or misfolded TIF1g proteins leads to cell stress and immunogenic death, (ii) the adaptive immune response is directed against both the misfolded part of TIF1g or the whole native TIF1g(using immunoediting), (iii) there are specific T cells against TIF1g (by using a previously described sorting method 39), and (iv) whether anti-TIF1g are pathogenic (in co-culture with fibrobladts and by immunizing mice against TIF1g