A differential role of macrophage TRPM2 channels in Ca2+ signaling and cell death in early responses to H2O2

2013 ◽  
Vol 305 (1) ◽  
pp. C61-C69 ◽  
Author(s):  
Jie Zou ◽  
Justin F. Ainscough ◽  
Wei Yang ◽  
Alicia Sedo ◽  
Shu-Ping Yu ◽  
...  
Keyword(s):  
Cell Death ◽  
Transient Receptor Potential ◽  
Parp Inhibitor ◽  
Dependent Manner ◽  
Release Channel ◽  
Permeable Channel ◽  
Macrophage Cells ◽  
Transient Receptor Potential Melastatin ◽  
Trpm2 Channel ◽  
Trpm2 Channels

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+]c were completely abolished in macrophage cells isolated from trpm2 −/− mice. H2O2 reduced macrophage cell viability in a duration- and concentration-dependent manner. H2O2-induced cell death was significantly attenuated by pretreatment with PJ-34 and TRPM2 channel deficiency but remained significant and persistent. Taken together, these results show that the TRPM2 channel in macrophage cells functions as a cell surface Ca2+-permeable channel that mediates Ca2+ influx and constitutes the principal Ca2+ signaling mechanism but has a limited, albeit significant, role in cell death during early exposure to H2O2.

scholarly journals Glia and TRPM2 Channels in Plasticity of Central Nervous System and Alzheimer’s Diseases

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Jing Wang ◽  
Michael F. Jackson ◽  
Yu-Feng Xie
Keyword(s):  
Oxidative Stress ◽  
Synaptic Plasticity ◽  
Glial Cells ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Synaptic Efficacy ◽  
Transient Receptor Potential Melastatin ◽  
Trpm2 Channel ◽  
Trpm2 Channels ◽  
Transient Receptor

Synaptic plasticity refers to the ability of neurons to strengthen or weaken synaptic efficacy in response to activity and is the basis for learning and memory. Glial cells communicate with neurons and in this way contribute in part to plasticity in the CNS and to the pathology of Alzheimer’s disease (AD), a neurodegenerative disease in which impaired synaptic plasticity is causally implicated. The transient receptor potential melastatin member 2 (TRPM2) channel is a nonselective Ca2+-permeable channel expressed in both glial cells (microglia and astrocytes) and neurons. Recent studies indicated that TRPM2 regulates synaptic plasticity as well as the activation of glial cells. TRPM2 also modulates oxidative stress and inflammation through interaction with glial cells. As both oxidative stress and inflammation have been implicated in AD pathology, this suggests a possible contribution of TRPM2 to disease processes. Through modulating the homeostasis of glutathione, TRPM2 is involved in the process of aging which is a risk factor of AD. These results potentially point TRPM2 channel to be involved in AD through glial cells. This review summarizes recent advances in studying the contribution of TRPM2 in health and in AD pathology, with a focus on contributions via glia cells.

scholarly journals A Role for H2O2 and TRPM2 in the Induction of Cell Death: Studies in KGN Cells

Antioxidants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 518 ◽  
Author(s):  
Carsten Theo Hack ◽  
Theresa Buck ◽  
Konstantin Bagnjuk ◽  
Katja Eubler ◽  
Lars Kunz ◽  
...  
Keyword(s):  
Cell Death ◽  
Transient Receptor Potential ◽  
Therapeutic Potential ◽  
Apoptotic Cell ◽  
Receptor Potential ◽  
Granulosa Cell Tumor ◽  
Nadph Oxidase 4 ◽  
Transient Receptor Potential Melastatin ◽  
Trpm2 Channel

Recent studies showed that KGN cells, derived from a human granulosa cell tumor (GCT), express NADPH oxidase 4 (NOX4), an important source of H2O2. Transient receptor potential melastatin 2 (TRPM2) channel is a Ca2+ permeable cation channel that can be activated by H2O2 and plays an important role in cellular functions. It is also able to promote susceptibility to cell death. We studied expression and functionality of TRPM2 in KGN cells and examined GCT tissue microarrays (TMAs) to explore in vivo relevance. We employed live cell, calcium and mitochondrial imaging, viability assays, fluorescence activated cell sorting (FACS) analysis, Western blotting and immunohistochemistry. We confirmed that KGN cells produce H2O2 and found that they express functional TRPM2. H2O2 increased intracellular Ca2+ levels and N-(p-Amylcinnamoyl)anthranilic acid (ACA), a TRPM2 inhibitor, blocked this action. H2O2 caused mitochondrial fragmentation and apoptotic cell death, which could be attenuated by a scavenger (Trolox). Immunohistochemistry showed parallel expression of NOX4 and TRPM2 in all 73 tumor samples examined. The results suggest that GCTs can be endowed with a system that may convey susceptibility to cell death. If so, induction of oxidative stress may be beneficial in GCT therapy. Our results also imply a therapeutic potential for TRPM2 as a drug target in GCTs.

scholarly journals Ruling out pyridine dinucleotides as true TRPM2 channel activators reveals novel direct agonist ADP-ribose-2′-phosphate

2015 ◽  
Vol 145 (5) ◽  
pp. 419-430 ◽  
Author(s):  
Balázs Tóth ◽  
Iordan Iordanov ◽  
László Csanády
Keyword(s):  
Transient Receptor Potential ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Receptor Potential ◽  
Transient Receptor Potential Melastatin ◽  
Trpm2 Channel ◽  
Biological Interest ◽  
Trpm2 Channels ◽  
Transient Receptor ◽  
First Time

Transient receptor potential melastatin 2 (TRPM2), a Ca2+-permeable cation channel implicated in postischemic neuronal cell death, leukocyte activation, and insulin secretion, is activated by intracellular ADP ribose (ADPR). In addition, the pyridine dinucleotides nicotinamide-adenine-dinucleotide (NAD), nicotinic acid–adenine-dinucleotide (NAAD), and NAAD-2′-phosphate (NAADP) have been shown to activate TRPM2, or to enhance its activation by ADPR, when dialyzed into cells. The precise subset of nucleotides that act directly on the TRPM2 protein, however, is unknown. Here, we use a heterologously expressed, affinity-purified–specific ADPR hydrolase to purify commercial preparations of pyridine dinucleotides from substantial contaminations by ADPR or ADPR-2′-phosphate (ADPRP). Direct application of purified NAD, NAAD, or NAADP to the cytosolic face of TRPM2 channels in inside-out patches demonstrated that none of them stimulates gating, or affects channel activation by ADPR, indicating that none of these dinucleotides directly binds to TRPM2. Instead, our experiments identify for the first time ADPRP as a true direct TRPM2 agonist of potential biological interest.

scholarly journals Selective profiling of N- and C-terminal nucleotide-binding sites in a TRPM2 channel

2020 ◽  
Vol 152 (5) ◽  
Author(s):  
Balázs Tóth ◽  
Iordan Iordanov ◽  
László Csanády
Keyword(s):  
Transient Receptor Potential ◽  
Channel Gating ◽  
Functional Independence ◽  
Site Directed Mutagenesis ◽  
Amino Acid Side Chain ◽  
Channel Activation ◽  
Transient Receptor Potential Melastatin ◽  
Trpm2 Channel ◽  
Trpm2 Channels ◽  
Terminal Site

Transient receptor potential melastatin 2 (TRPM2) is a homotetrameric Ca2+-permeable cation channel important for the immune response, body temperature regulation, and insulin secretion, and is activated by cytosolic Ca2+ and ADP ribose (ADPR). ADPR binds to two distinct locations, formed by large N- and C-terminal cytosolic domains, respectively, of the channel protein. In invertebrate TRPM2 channels, the C-terminal site is not required for channel activity but acts as an active ADPR phosphohydrolase that cleaves the activating ligand. In vertebrate TRPM2 channels, the C-terminal site is catalytically inactive but cooperates with the N-terminal site in channel activation. The precise functional contributions to channel gating and the nucleotide selectivities of the two sites in various species have not yet been deciphered. For TRPM2 of the sea anemone Nematostella vectensis (nvTRPM2), catalytic activity is solely attributable to the C-terminal site. Here, we show that nvTRPM2 channel gating properties remain unaltered upon deletion of the C-terminal domain, indicating that the N-terminal site is single-handedly responsible for channel gating. Exploiting such functional independence of the N- and C-terminal sites, we selectively measure their affinity profiles for a series of ADPR analogues, as reflected by apparent affinities for channel activation and catalysis, respectively. Using site-directed mutagenesis, we confirm that the same N-terminal site observed in vertebrate TRPM2 channels was already present in ancient cnidarians. Finally, by characterizing the functional effects of six amino acid side chain truncations in the N-terminal site, we provide first insights into the mechanistic contributions of those side chains to TRPM2 channel gating.

scholarly journals Ethanol Induces Microglial Cell Death via the NOX/ROS/PARP/TRPM2 Signalling Pathway

Antioxidants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1253
Author(s):  
Muhammad Syahreel Azhad Sha’fie ◽  
Sharani Rathakrishnan ◽  
Iffa Nadhira Hazanol ◽  
Mohd Haziq Izzazuddin Dali ◽  
Mohd Ezuan Khayat ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Microglial Cell ◽  
Transient Receptor Potential ◽  
Immune Cell ◽  
Critical Role ◽  
Microglial Cells ◽  
Transient Receptor Potential Melastatin ◽  
Trpm2 Channel

Microglial cells are the primary immune cell resident in the brain. Growing evidence indicates that microglial cells play a prominent role in alcohol-induced brain pathologies. However, alcohol-induced effects on microglial cells and the underlying mechanisms are not fully understood, and evidence exists to support generation of oxidative stress due to NADPH oxidases (NOX_-mediated production of reactive oxygen species (ROS). Here, we investigated the role of the oxidative stress-sensitive Ca2+-permeable transient receptor potential melastatin-related 2 (TRPM2) channel in ethanol (EtOH)-induced microglial cell death using BV2 microglial cells. Like H2O2, exposure to EtOH induced concentration-dependent cell death, assessed using a propidium iodide assay. H2O2/EtOH-induced cell death was inhibited by treatment with TRPM2 channel inhibitors and also treatment with poly(ADP-ribose) polymerase (PARP) inhibitors, demonstrating the critical role of PARP and the TRPM2 channel in EtOH-induced cell death. Exposure to EtOH, as expected, led to an increase in ROS production, shown using imaging of 2’,7’-dichlorofluorescein fluorescence. Consistently, EtOH-induced microglial cell death was suppressed by inhibition of NADPH oxidase (NOX) as well as inhibition of protein kinase C. Taken together, our results suggest that exposure to high doses of ethanol can induce microglial cell death via the NOX/ROS/PARP/TRPM2 signaling pathway, providing novel and potentially important insights into alcohol-induced brain pathologies.

scholarly journals TRPM2-mediated intracellular Zn2+ release triggers pancreatic β-cell death

2015 ◽  
Vol 466 (3) ◽  
pp. 537-546 ◽  
Author(s):  
Paul T. Manna ◽  
Tim S. Munsey ◽  
Nada Abuarab ◽  
Fangfang Li ◽  
Aruna Asipu ◽  
...  
Keyword(s):  
Cell Death ◽  
Transient Receptor Potential ◽  
Apoptotic Cell ◽  
Receptor Potential ◽  
Primary Role ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Hek 293 ◽  
Transient Receptor Potential Melastatin ◽  
Trpm2 Channels

Reactive oxygen species (ROS) can cause pancreatic β-cell death by activating transient receptor potential (melastatin) 2 (TRPM2) channels. Cell death has been attributed to the ability of these channels to raise cytosolic Ca2+. Recent studies however revealed that TRPM2 channels can also conduct Zn2+, but the physiological relevance of this property is enigmatic. Given that Zn2+ is cytotoxic, we asked whether TRPM2 channels can permeate sufficient Zn2+ to affect cell viability. To address this, we used the insulin secreting (INS1) β-cell line, human embryonic kidney (HEK)-293 cells transfected with TRPM2 and pancreatic islets. H2O2 activation of TRPM2 channels increases the cytosolic levels of both Ca2+ and Zn2+ and causes apoptotic cell death. Interestingly, chelation of Zn2+ alone was sufficient to prevent β-cell death. The source of the cytotoxic Zn2+ is intracellular, found largely sequestered in lysosomes. Lysosomes express TRPM2 channels, providing a potential route for Zn2+ release. Zn2+ release is potentiated by extracellular Ca2+ entry, indicating that Ca2+-induced Zn2+ release leads to apoptosis. Knockout of TRPM2 channels protects mice from β-cell death and hyperglycaemia induced by multiple low-dose streptozotocin (STZ; MLDS) administration. These results argue that TRPM2-mediated, Ca2+-potentiated Zn2+ release underlies ROS-induced β-cell death and Zn2+, rather than Ca2+, plays a primary role in apoptosis.

Pharmacological Inhibition of Transient Receptor Potential Melastatin 2 (TRPM2) Channels Attenuates Diabetes-induced Cognitive Deficits in Rats: A Mechanistic Study

2020 ◽  
Vol 17 (3) ◽  
pp. 249-258 ◽  
Author(s):  
Pavan Thapak ◽  
Mahendra Bishnoi ◽  
Shyam S. Sharma
Keyword(s):  
Cognitive Impairment ◽  
Cognitive Deficits ◽  
Ache Activity ◽  
Transient Receptor Potential ◽  
Mrna Level ◽  
Receptor Potential ◽  
Transient Receptor Potential Melastatin ◽  
Trpm2 Channels ◽  
Transient Receptor ◽  
Gsk 3Β

Background: Diabetes is a chronic metabolic disorder affecting the central nervous system. A growing body of evidence has depicted that high glucose level leads to the activation of the transient receptor potential melastatin 2 (TRPM2) channels. However, there are no studies targeting TRPM2 channels in diabetes-induced cognitive decline using a pharmacological approach. Objective: The present study intended to investigate the effects of 2-aminoethoxydiphenyl borate (2-APB), a TRPM2 inhibitor, in diabetes-induced cognitive impairment. Methods: Streptozotocin (STZ, 50 mg/kg, i.p.) was used to induce diabetes in rats. Animals were randomly divided into the treatment group, model group and age-matched control and pre se group. 2-APB treatment was given for three weeks to the animals. After 10 days of behavioural treatment, parameters were performed. Animals were sacrificed at 10th week of diabetic induction and the hippocampus and cortex were isolated. After that, protein and mRNA expression study was performed in the hippocampus. Acetylcholinesterase (AchE) activity was done in the cortex. Results: : Our study showed the 10th week diabetic animals developed cognitive impairment, which was evident from the behavioural parameters. Diabetic animals depicted an increase in the TRPM2 mRNA and protein expression in the hippocampus as well as increased AchE activity in the cortex. However, memory associated proteins were down-regulated, namely Ca2+/calmodulin-dependent protein kinase II (CaMKII-Thr286), glycogen synthase kinase 3 beta (GSK-3β-Ser9), cAMP response element-binding protein (CREB-Ser133), and postsynaptic density protein 95 (PSD-95). Gene expression of parvalbumin, calsequestrin and brain-derived neurotrophic factor (BDNF) were down-regulated while mRNA level of calcineurin A/ protein phosphatase 3 catalytic subunit alpha (PPP3CA) was upregulated in the hippocampus of diabetic animals. A three-week treatment with 2-APB significantly ameliorated the alteration in behavioural cognitive parameters in diabetic rats. Moreover, 2-APB also down-regulated the expression of TRPM2 mRNA and protein in the hippocampus as well as AchE activity in the cortex of diabetic animals as compared to diabetic animals. Moreover, the 2-APB treatment also upregulated the CaMKII (Thr-286), GSK-3β (Ser9), CREB (Ser133), and PSD-95 expression and mRNA levels of parvalbumin, calsequestrin, and BDNF while mRNA level of calcineurin A was down-regulated in the hippocampus of diabetic animals. Conclusion: : This study confirms the ameliorative effect of TRPM2 channel inhibitor in the diabetes- induced cognitive deficits. Inhibition of TRPM2 channels reduced the calcium associated downstream signaling and showed a neuroprotective effect of TRPM2 channels in diabetesinduced cognitive impairment.

scholarly journals The proposed channel-enzyme transient receptor potential melastatin 2 does not possess ADP ribose hydrolase activity

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Iordan Iordanov ◽  
Csaba Mihályi ◽  
Balázs Tóth ◽  
László Csanády
Keyword(s):  
Cell Death ◽  
Insulin Secretion ◽  
Transient Receptor Potential ◽  
Channel Gating ◽  
Receptor Potential ◽  
Cation Channel ◽  
Chimeric Proteins ◽  
Transient Receptor Potential Melastatin ◽  
Biochemical Studies ◽  
Transient Receptor

Transient Receptor Potential Melastatin 2 (TRPM2) is a Ca2+-permeable cation channel essential for immunocyte activation, insulin secretion, and postischemic cell death. TRPM2 is activated by ADP ribose (ADPR) binding to its C-terminal cytosolic NUDT9-homology (NUDT9H) domain, homologous to the soluble mitochondrial ADPR pyrophosphatase (ADPRase) NUDT9. Reported ADPR hydrolysis classified TRPM2 as a channel-enzyme, but insolubility of isolated NUDT9H hampered further investigations. Here we developed a soluble NUDT9H model using chimeric proteins built from complementary polypeptide fragments of NUDT9H and NUDT9. When expressed in E.coli, chimeras containing up to ~90% NUDT9H sequence remained soluble and were affinity-purified. In ADPRase assays the conserved Nudix-box sequence of NUDT9 proved essential for activity (kcat~4-9s-1), that of NUDT9H did not support catalysis. Replacing NUDT9H in full-length TRPM2 with soluble chimeras retained ADPR-dependent channel gating (K1/2~1-5 μM), confirming functionality of chimeric domains. Thus, TRPM2 is not a 'chanzyme'. Chimeras provide convenient soluble NUDT9H models for structural/biochemical studies.

Sign in / Sign up

Export Citation Format

Share Document