Dendritic cells (DCs) are multi-potent regulators of the immune system. Many critical DC functions involve calcium (Ca2+) signaling. Ca2+ is the most versatile eukaryotic intracellular messenger that mediates regulation of many processes important to cell life. Ca2+ levels in DCs and many other immune cell types are tightly regulated through multiple mechanisms during the resting state as well as during activation. Chemokine receptor stimulation increases intracellular Ca2+ concentration ([Ca2+]i) and chemotaxis in DCs. Despite important advances in our understanding of Ca2+ signaling in lymphocytes, the molecular players involved in shaping intracellular Ca2+ in DCs remain to be characterized. The current paradigm states that increases in DC cytosolic Ca2+ levels are caused by release from endoplasmic reticulum (ER) Ca2+ stores and/or via influx of extracellular Ca2+ by opening of store-operated Ca2+ channels at the plasma membrane. We propose a novel Ca2+ release mechanism in DCs, which operates via a Ca2+ channel expressed on lysosomal compartments and, we postulate this pathway is essential for Ca2+-dependent DC functions. Preliminary data that support our proposal show: i) Exclusive localization of functional Ca2+-permeant melastatin-related transient receptor potential channel (TRPM2) in endolysosomal compartments of DCs. ii) Both adenosine diphosphoribose (ADPR) and chemokines induce TRPM2 mediated Ca2+ signals in DCs, iii) TRPM2 channel acts as a Ca2+ release channel in DCs. iv) TRPM2-deficient DCs exhibit impaired chemotactic responses to chemokines. v) TRPM2-deficient mice elicit reduced inflammatory recruitment upon infection. Based upon these data, we hypothesize that: TRPM2 functions as an intracellular lysosome- associated calcium release channel that regulates Ca2+-dependent processes in DCs. To critically test our hypothesis, we propose the following specific aims:
Aim 1. Identify mechanisms of activation of Ca2+ release via TRPM2 channel, and elucidate how this pathway impacts on DC Ca2+-dependent functions.
Aim 2. Define the specific roles for TRPM2-mediated Ca2+ signaling in DCs during inflammation, immunization and cellular inflammatory infiltration to the mucosa using a mouse model of urinary tract infection. The findings from this proposal will provide insights into how the intracellular function of TRPM2 channel affects Ca2+-mediated signal transduction pathways that play a central regulatory role during DC responses. The completion of these studies will unveil the utility of new pharmacological targets (ADPR and/or TRPM2) for manipulation of DCs'Ca2+responses and functions, and will further facilitate the design of new therapeutic strategies for chronic inflammatory or infectious diseases, where DCs may play important pathogenic roles.
Dendritic cells play a critical role in initiating and regulating immunity. This grant proposes to elucidate a novel calcium release mechanism that regulates calcium homeostasis and therefore, calcium-dependent functions in dendritic cells. The successful completion of the experiments proposed here will provide insights into a signaling pathway in dendritic cells, which has strong potential to uncover novel therapeutic targets, and unappreciated approaches for chronic inflammatory diseases.
|Beceiro, S; Radin, J N; Chatuvedi, R et al. (2016) TRPM2 ion channels regulate macrophage polarization and gastric inflammation during Helicobacter pylori infection. Mucosal Immunol :|
|Ruiz-Rosado, Juan de Dios; OlguÃn, Jonadab E; JuÃ¡rez-Avelar, Imelda et al. (2016) MIF Promotes Classical Activation and Conversion of Inflammatory Ly6C(high) Monocytes into TipDCs during Murine Toxoplasmosis. Mediators Inflamm 2016:9101762|
|Li, Birong; Haridas, Babitha; Jackson, Ashley R et al. (2016) Inflammation Drives Renal Scarring in Experimental Pyelonephritis. Am J Physiol Renal Physiol :ajprenal.00471.2016|
|Lee, Yong-Ung; de Dios Ruiz-Rosado, Juan; Mahler, Nathan et al. (2016) TGF-Î² receptor 1 inhibition prevents stenosis of tissue-engineered vascular grafts by reducing host mononuclear phagocyte activation. FASEB J 30:2627-36|
|Becknell, Brian; Eichler, Tad E; Beceiro, Susana et al. (2015) Ribonucleases 6 and 7 have antimicrobial function in the human and murine urinary tract. Kidney Int 87:151-61|
|Petrovic-Djergovic, D; Popovic, M; Chittiprol, S et al. (2015) CXCL10 induces the recruitment of monocyte-derived macrophages into kidney, which aggravate puromycin aminonucleoside nephrosis. Clin Exp Immunol 180:305-15|
|Tara, Shuhei; Kurobe, Hirotsugu; de Dios Ruiz Rosado, Juan et al. (2015) Cilostazol, Not Aspirin, Prevents Stenosis of Bioresorbable Vascular Grafts in a Venous Model. Arterioscler Thromb Vasc Biol 35:2003-10|
|Jablonski, Kyle A; Amici, Stephanie A; Webb, Lindsay M et al. (2015) Novel Markers to Delineate Murine M1 and M2 Macrophages. PLoS One 10:e0145342|
|Bolton, Michael; Horvath Jr, Dennis J; Li, Birong et al. (2012) Intrauterine growth restriction is a direct consequence of localized maternal uropathogenic Escherichia coli cystitis. PLoS One 7:e33897|
|McNally, Beth; Willette, Meredith; Ye, Fang et al. (2012) Intranasal administration of dsRNA analog poly(I:C) induces interferon-Î± receptor-dependent accumulation of antigen experienced T cells in the airways. PLoS One 7:e51351|
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