Uric acid induces caspase-1 activation, IL-1β secretion and P2X7 receptor dependent proliferation in primary human lymphocytes.

BACKGROUND Urate through Nacht Domain, Leucine-Rich Repeat, and pyrin domain-containing protein 3 (NALP3) dependent caspase-1 activation stimulates macrophages to secrete inteleukin-1β (IL-1β). Purinergic receptor P2X7 plays a role in the urate induced NALP3 activation. Urate also enhances adaptive immunity indirectly through its effect on antigen presenting cells. In this study, the direct effect of urate on primary human lymphocytes was evaluated. METHODS Lymphocytes were cultured with or without monosodium urate crystals in the presence or not of a P2X7 inhibitor. Caspase-1 activity was assessed colorimetrically in cell lysates and IL-1β was measured in supernatants with ELISA. Whole lymphocyte viability and proliferation, as well as T-cell proliferation were assessed by means of 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay and of flow cytometry respectively. RESULTS Urate induced caspase-1 activation and IL-1β release by lymphocytes. It also induced proliferation of whole lymphocytes and T-cells as well. P2X7 inhibitor abrogated lymphocyte proliferation. CONCLUSIONS Urate, a well defined danger signal, stimulates directly human lymphocytes in a P2X7 dependent way. The subsequent IL-1β secretion could enhance inflammation, whereas expansion of lymphocyte clones could facilitate a subsequent adaptive immune response.

[1]  D. Green,et al.  Armed response: how dying cells influence T‐cell functions , 2011, Immunological reviews.

[2]  Grace Y Chen,et al.  Sterile inflammation: sensing and reacting to damage , 2010, Nature Reviews Immunology.

[3]  J. Tschopp,et al.  Uric acid is a danger signal activating NALP3 inflammasome in lung injury inflammation and fibrosis , 2008 .

[4]  Xiao-Jun Ma,et al.  Uric acid enhances T cell immune responses to hepatitis B surface antigen-pulsed-dendritic cells in mice. , 2007, World journal of gastroenterology.

[5]  Yanping Huang,et al.  T Cell Receptor Signaling: Beyond Complex Complexes* , 2004, Journal of Biological Chemistry.

[6]  P. Sivaramakrishnan,et al.  Receptors and signaling mechanisms for B‐lymphocyte activation, proliferation and differentiation – Insights from both in vivo and in vitro approaches , 2010, FEBS letters.

[7]  H. Kita,et al.  Human Eosinophils Recognize Endogenous Danger Signal Crystalline Uric Acid and Produce Proinflammatory Cytokines Mediated by Autocrine ATP , 2010, The Journal of Immunology.

[8]  G. Dubyak,et al.  Isoquinolines as antagonists of the P2X7 nucleotide receptor: high selectivity for the human versus rat receptor homologues. , 1998, Molecular pharmacology.

[9]  T. Pawełczyk,et al.  High glucose concentration impairs ATP outflow and immunoglobulin production by human peripheral B lymphocytes: involvement of P2X7 receptor. , 2013, Immunobiology.

[10]  A. Surprenant,et al.  Pannexin‐1 mediates large pore formation and interleukin‐1β release by the ATP‐gated P2X7 receptor , 2006, The EMBO journal.

[11]  M. Bianchi.  DAMPs, PAMPs and alarmins: all we need to know about danger , 2007, Journal of leukocyte biology.

[12]  C. Gargett,et al.  The isoquinoline derivative KN‐62 a potent antagonist of the P2Z‐receptor of human lymphocytes , 1997, British journal of pharmacology.

[13]  J. Buer,et al.  Purinergic Control of T Cell Activation by ATP Released Through Pannexin-1 Hemichannels , 2008, Science Signaling.

[14]  Dirk E. Smith,et al.  The IL-1 family: regulators of immunity , 2010, Nature Reviews Immunology.

[15]  G. Dahl,et al.  Activation of pannexin 1 channels by ATP through P2Y receptors and by cytoplasmic calcium , 2006, FEBS letters.

[16]  W. Junger,et al.  Hypertonic stress regulates T cell function via pannexin‐1 hemichannels and P2X receptors , 2010, Journal of leukocyte biology.

[17]  F. Martinon,et al.  Gout-associated uric acid crystals activate the NALP3 inflammasome , 2006, Nature.

[18]  K. Riesbeck,et al.  Nucleotide‐binding and oligomerization domain‐like receptors and retinoic acid inducible gene‐like receptors in human tonsillar T lymphocytes , 2011, Immunology.

[19]  Fabio Grassi,et al.  ATP Inhibits the Generation and Function of Regulatory T Cells Through the Activation of Purinergic P2X Receptors , 2011, Science Signaling.

[20]  Henk C. Hoogsteden,et al.  Alum adjuvant boosts adaptive immunity by inducing uric acid and activating inflammatory dendritic cells , 2008, The Journal of experimental medicine.

[21]  W. Junger,et al.  Immune cell regulation by autocrine purinergic signalling , 2011, Nature Reviews Immunology.

[22]  K. Rock,et al.  Uric acid promotes an acute inflammatory response to sterile cell death in mice. , 2010, The Journal of clinical investigation.

[23]  P. Insel,et al.  Autocrine regulation of T‐cell activation by ATP release and P2X7 receptors , 2009, FASEB journal : official publication of the Federation of American Societies for Experimental Biology.

[24]  Kim M. Huffman,et al.  Uric acid is a danger signal of increasing risk for osteoarthritis through inflammasome activation , 2011, Proceedings of the National Academy of Sciences.

[25]  P. Preshaw,et al.  The expanding family of interleukin‐1 cytokines and their role in destructive inflammatory disorders , 2007, Clinical and experimental immunology.

[26]  Richard A. Flavell,et al.  The Nalp3 inflammasome is essential for the development of silicosis , 2008, Proceedings of the National Academy of Sciences.

[27]  M. Jeffries,et al.  Uric Acid Directly Promotes Human T-Cell Activation , 2009, The American journal of the medical sciences.

[28]  L. Thomsen,et al.  Uric Acid Promotes Tumor Immune Rejection , 2004, Cancer Research.

[29]  A. So,et al.  Expression and function of the NALP3 inflammasome in rheumatoid synovium , 2010, Immunology.

[30]  P. Insel,et al.  Pannexin-1 hemichannel-mediated ATP release together with P2X1 and P2X4 receptors regulate T-cell activation at the immune synapse. , 2010, Blood.

[31]  C. Gargett,et al.  Partial agonists and antagonists reveal a second permeability state of human lymphocyte P2Z/P2X7channel. , 1998, American journal of physiology. Cell physiology.

[32]  F. Martinon,et al.  Activation of the NALP3 inflammasome is triggered by low intracellular potassium concentration , 2007, Cell Death and Differentiation.

[33]  C. Gargett,et al.  Partial agonists and antagonists reveal a second permeability state of human lymphocyte P2Z/P2X7 channel. , 1998, The American journal of physiology.

[34]  James E. Evans,et al.  Molecular identification of a danger signal that alerts the immune system to dying cells , 2003, Nature.