TRPM2 Channel-Mediated ROS-Sensitive Ca(2+) Signaling Mechanisms in Immune Cells (original) (raw)
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The transient receptor potential melastatin-2 (TRPM2) channel and inflammation
Inflammation is an early mechanism of the immune system to eliminate pathogens and to repair damaged tissue. However, unregulated and persistent inflammation can lead to chronic inflammatory diseases. The transient receptor potential melastatin-2 (TRPM2) channel, a calcium (Ca2+)-permeable channel containing intracellular adenosine diphosphate ribose (ADPR) pyrohydrolase activity, has recently been identified as a critical molecular mechanism in reactive oxygen species (ROS)-induced inflammatory process, and thereby, emerged as a potential target for therapeutic intervention. ADPR biding to TRPM2 Nudix-like domain (or NUDT9 homology domain) results in the channel pore opening allowing lysosomal Ca2+ release and Ca2+ influx into the cells. Ca2+ influx via TRPM2 controls ROS-induced nuclear translocation of NF-κB and CXCL2 production in monocytes during inflammation in a chronic experimental colitis mouse model. Moreover, TRPM2 deficient-dendritic cells show defective Ca2+ signals and...
TRPM2: a multifunctional ion channel for calcium signalling
Journal of Physiology-London, 2011
The transient potential receptor melastatin-2 (TRPM2) channel has emerged as an important Ca 2+ signalling mechanism in a variety of cells, contributing to cellular functions that include cytokine production, insulin release, cell motility and cell death. Its ability to respond to reactive oxygen species has made TRPM2 a potential therapeutic target for chronic inflammation, neurodegenerative diseases, and oxidative stress-related pathologies. TRPM2 is a non-selective, calcium (Ca 2+)-permeable cation channel of the melastatin-related transient receptor potential (TRPM) ion channel subfamily. It is activated by intracellular adenosine diphosphate ribose (ADPR) through a diphosphoribose hydrolase domain in its C-terminus and regulated through a variety of factors, including synergistic facilitation by [Ca 2+ ] i , cyclic ADPR, H 2 O 2 , NAADP, and negative feedback regulation by AMP and permeating protons (pH). In addition to its role mediating Ca 2+ influx into the cells, TRPM2 can also function as a lysosomal Ca 2+ release channel, contributing to cell death. The physiological and pathophysiological context of ROS-mediated events makes TRPM2 a promising target for the development of therapeutic tools of inflammatory and degenerative diseases.
The redox-sensitive cation channel TRPM2 modulates phagocyte ROS production and inflammation
Nature Immunology, 2011
The NADPH oxidase activity of phagocytes and its generation of reactive oxygen species (ROS) is critical for host-defense, but ROS overproduction can also lead to inflammation and tissue injury. Here we report that TRPM2, a non-selective and redox-sensitive cation channel, inhibits ROS production in phagocytic cells and prevents endotoxin-induced lung inflammation in mice. TRPM2-deficient mice challenged with endotoxin (lipopolysaccharide) showed an increased inflammatory signature and decreased survival compared to controls. TRPM2 functions by dampening NADPH oxidase-mediated ROS production through depolarization of the plasma membrane in phagocytes. Since ROS also activates TRPM2, our findings establish a negative feedback mechanism inactivating ROS production through inhibition of the membrane potentialsensitive NADPH oxidase.
TRPM channels as potential therapeutic targets against pro-inflammatory diseases
Cell calcium, 2017
The immune system protects our body against foreign pathogens. However, if it overshoots or turns against itself, pro-inflammatory diseases, such as rheumatoid arthritis, inflammatory bowel disease, or diabetes develop. Ions, the most basic signaling molecules, shape intracellular signaling cascades resulting in immune cell activation and subsequent immune responses. Mutations in ion channels required for calcium signaling result in human immunodeficiencies and highlight those ion channels as valued targets for therapies against pro-inflammatory diseases. Signaling pathways regulated by melastatin-like transient receptor potential (TRPM) cation channels also play crucial roles in calcium signaling and leukocyte physiology, affecting phagocytosis, degranulation, chemokine and cytokine expression, chemotaxis and invasion, as well as lymphocyte development and proliferation. Therefore, this review discusses their regulation, possible interactions and whether they can be exploited as ta...
FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 2018
Neutrophil extracellular trap (NET) formation constitutes an important extracellular antimicrobial function of neutrophils that plays a protective role in bacterial pneumonia. Formation of reactive oxygen species (ROS) such as highly diffusible hydrogen peroxide (HO) is a hallmark of oxidative stress during inflammatory lung conditions including pneumonia. However, the impact of exogenous ROS on NET formation and the signaling pathway involved in the process is not completely understood. Here we demonstrate that the ROS-sensing, nonselective, calcium-permeable channel transient receptor potential melastatin 2 (TRPM2) is required for NET formation in response to exogenous HO. This TRPM2-dependent HO-mediated NET formation involved components of autophagy and activation of AMPK and p38 MAPK, but not PI3K and AKT. Primary neutrophils from Trpm2 mice fail to activate this pathway with a block in NET release and a concomitant decrease in their antimicrobial capacity. Consequently, Trpm2 ...
Journal of Inflammation, 2013
Background Airway inflammation and asthma have been linked to oxidative stress and the melastatin-related transient receptor potential cation channel, member 2 (TRPM2), which can be activated by reactive oxygen species (ROS), has emerged as a potential therapeutic target for inflammatory diseases. Objective Using TRPM2 deficient (TRPM2-/-) mice, we investigated whether the TRPM2 ion channel, which mediates calcium (Ca2+) influx and lysosomal Ca2+ release, plays a role in the pathophysiology of severe allergic asthma in mouse. Methods Severe allergic asthma was initiated in wild type (WT) and TRPM2-/- mice by repeated sensitization with ovalbumin (OVA)/aluminum hydroxide on Days 0, 7 and 14, followed by intranasal challenge on Days 21, 22 and 23. Mice were investigated for the presence of airway responsiveness, airway inflammation, production of allergen-specific antibodies, cytokine response and lung pathology. Results The absence of TRPM2 channels has no obvious effect on major eti...
American Journal of Physiology-Cell Physiology, 2013
Reactive oxygen species such as H2O2 elevates the cytosolic Ca2+ concentration ([Ca2+]c) and causes cell death via poly(ADPR) polymerase (PARP) activation, which also represents the primary mechanism by which H2O2 activate the transient receptor potential melastatin-related 2 (TRPM2) channel as a Ca2+-permeable channel present in the plasma membrane or an intracellular Ca2+-release channel. The present study aimed to define the contribution and mechanisms of the TRPM2 channels in macrophage cells in mediating Ca2+ signaling and cell death during initial response to H2O2, using mouse peritoneal macrophage, RAW264.7, and differentiated THP-1 cells. H2O2 evoked robust increases in the [Ca2+]c, and such Ca2+ responses were significantly greater at body temperature than room temperature. H2O2-induced Ca2+ responses were strongly inhibited by pretreatment with PJ-34, a PARP inhibitor, and largely prevented by removal of extracellular Ca2+. Furthermore, H2O2-induced increases in the [Ca2+]...
Proceedings of the National Academy of Sciences, 2011
The generation of reactive oxygen species (ROS) is inherent to immune responses. ROS are crucially involved in host defense against pathogens by promoting bacterial killing, but also as signaling agents coordinating the production of cytokines. Transient Receptor Potential Melastatin 2 (TRPM2) is a Ca 2+ -permeable channel gated via binding of ADP-ribose, a metabolite formed under conditions of cellular exposure to ROS. Here, we show that TRPM2deficient mice are extremely susceptible to infection with Listeria monocytogenes (Lm), exhibiting an inefficient innate immune response. In a comparison with IFNγR-deficient mice, TRPM2 −/− mice shared similar features of uncontrolled bacterial replication and reduced levels of inducible (i)NOS-expressing monocytes, but had intact IFNγ responsiveness. In contrast, we found that levels of cytokines IL-12 and IFNγ were diminished in TRPM2 −/− mice following Lm infection, which correlated with their reduced innate activation. Moreover, TRPM2 −/− mice displayed a higher degree of susceptibility than IL-12-unresponsive mice, and supplementation with recombinant IFNγ was sufficient to reverse the unrestrained bacterial growth and ultimately the lethal phenotype of Lminfected TRPM2 −/− mice. The severity of listeriosis we observed in TRPM2 −/− mice has not been reported for any other ion channel. These findings establish an unsuspected role for ADP-ribose and ROS-mediated cation flux for innate immunity, opening up unique possibilities for immunomodulatory intervention through TRPM2. CXCL2 | IL-12Rβ2 −/− | NAD | pathogen-associated molecular pattern | NF-κB
Cell Communication and Signaling
The transient receptor potential melastatin subfamily member 2 (TRPM2), a thermo and reactive oxygen species (ROS) sensitive Ca2+-permeable cation channel has a vital role in surviving the cell as well as defending the adaptability of various cell groups during and after oxidative stress. It shows higher expression in several cancers involving breast, pancreatic, prostate, melanoma, leukemia, and neuroblastoma, indicating it raises the survivability of cancerous cells. In various cancers including gastric cancers, and neuroblastoma, TRPM2 is known to conserve viability, and several underlying mechanisms of action have been proposed. Transcription factors are thought to activate TRPM2 channels, which is essential for cell proliferation and survival. In normal physiological conditions with an optimal expression of TRPM2, mitochondrial ROS is produced in optimal amounts while regulation of antioxidant expression is carried on. Depletion of TRPM2 overexpression or activity has been show...
TRPM2 functions as a lysosomal Ca2+-release channel in beta cells
Science signaling, 2009
TRPM2 is a Ca2+-permeable cation channel that is specifically activated by adenosine diphosphoribose (ADPR). Channel activation in the plasma membrane leads to Ca2+ influx and has been linked to apoptotic mechanisms. The primary agonist, ADPR, is produced both extra- and intracellularly and causes increases in intracellular calcium concentration ([Ca2+]i), but the mechanisms involved are not understood. Using short interfering RNA and a knockout mouse, we report that TRPM2, in addition to its role as a plasma membrane channel, also functions as a Ca2+-release channel activated by intracellular ADPR in a lysosomal compartment. We show that both functions of TRPM2 are critically linked to hydrogen peroxide-induced beta cell death. Additionally, extracellular ADPR production by the ectoenzyme CD38 from its substrates NAD+ (nicotinamide adenine dinucleotide) or cADPR causes IP3-dependent Ca2+ release via P2Y and adenosine receptors. Thus, ADPR and TRPM2 represent multimodal signaling el...