posted on 2019-05-16, 13:00authored byS Dimeloe, LV Rice, H Chen, C Cheadle, J Raynes, P Pfeffer, P Lavender, DF Richards, MP Nyon, JM McDonnell, C Kemper, B Gooptu, CM Hawrylowicz
Studies to identify novel immune-regulatory functions of active vitamin D (1,25(OH)2D3) in human CD4+ T cells revealed that 1,25(OH)2D3 potently induced expression of the gene SERPINA1, encoding the anti-protease α-1-antitrypsin. We confirmed α-1-antitrypsin protein expression by 1,25(OH)2D3-treated CD4+ T cells, but not in CD8+ T cells or monocytes. α-1-Antitrypsin promotes anti-inflammatory IL-10 synthesis in other immune cell populations. We therefore investigated its immune-regulatory effects in CD4+ T cells. Plasma-derived α-1-antitrypsin drove IL-10 synthesis by CD4+ T cells, which was not dependent on anti-protease activity, but appeared to require a serum-binding factor, since this could not be achieved with recombinant protein. α-1-Antitrypsin is reported to bind complement components, which regulate T cell function. A role for this interaction was therefore probed. Plasma-derived, but not recombinant α-1-antitrypsin contained C3a. Surface Plasmon Resonance and Microscale Thermophoresis demonstrated α-1-antitrypsin binding to C3a. Addition of C3a to CD4+ T cells cultured with recombinant α-1-antitrypsin restored induction of IL-10, whereas neutralisation of C3a abrogated IL-10 induced by plasma-derived α-1-antitrypsin. To interrogate an endogenous role for the α-1-antitrypsin-C3a axis in 1,25(OH)2D3-driven CD4+ T cell IL-10 synthesis, we treated cells from healthy or α-1-antitrypsin-deficient individuals (which transcribe SERPINA1 but do not secrete protein) with 1,25(OH)2D3. A significant correlation was identified between SERPINA1 and IL10 gene expression in healthy donor CD4+ T cells, which was absent in cells from α-1-antitrypsin-deficient individuals. Therefore, α-1-antitrypsin is required for 1,25(OH)2D3-induced IL-10 expression in CD4+ T cells, interacting with C3a to drive IL-10 expression.
Funding
SD and LR were recipients of Medical Research Council (MRC) funded PhD Studentships through the MRC & Asthma UK Centre for Allergic Mechanisms of Asthma. CK was supported by an MRC Research Grant (Grant no. G1002165) and the Medical Research Council Centre for Transplantation, KCL. CH with LR, HC and CC, as well as MPN were supported by grants from the Alpha-1 Foundation. CMH, CK and PEP are supported by the Department of Health, National Institute for Health Research comprehensive Biomedical Research Centre award to Guy’s & St. Thomas’ NHS Foundation Trust in partnership with King’s College London and King’s College Hospital NHS Foundation Trust. We gratefully acknowledge the work undertaken to provide reagents by Marie Pang (KCL, London), Doris Quay (Birkbeck College, London) and Professor Joerg Koehl (Lubeck University, Germany) and the assistance of Professor David Lomas (UCL) and the Cambridge Institute of Medical Research (CIMR, University of Cambridge) for use of laboratory facilities. Microscale thermophoresis assays were conducted with the kind assistance of Dr Tina Daviter (ISMB Biophysics facility), Dr Mark Pfuhl (Randall Division, KCL) and Dr James Wilkinson (Nanotemper Technologies). We acknowledge support from our research nurse, Kheem Jones.
History
Citation
Journal of Steroid Biochemistry and Molecular Biology, 2019, 189, pp. 1-9
Author affiliation
/Organisation/COLLEGE OF LIFE SCIENCES/School of Medicine/Department of Infection, Immunity and Inflammation
Version
VoR (Version of Record)
Published in
Journal of Steroid Biochemistry and Molecular Biology