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 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.

scholarly journals Carvacrol Attenuates Hippocampal Neuronal Death after Global Cerebral Ischemia via Inhibition of Transient Receptor Potential Melastatin 7

Cells ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 231 ◽  
Author(s):  
Dae Hong ◽  
Bo Choi ◽  
A Kho ◽  
Song Lee ◽  
Jeong Jeong ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Neuronal Death ◽  
Transient Receptor Potential ◽  
Therapeutic Potential ◽  
Receptor Potential ◽  
Global Cerebral Ischemia ◽  
Neuroprotective Effects ◽  
Transient Receptor Potential Melastatin ◽  
Transient Receptor ◽  
Zinc Translocation

Over the last two decades, evidence supporting the concept of zinc-induced neuronal death has been introduced, and several intervention strategies have been investigated. Vesicular zinc is released into the synaptic cleft, where it then translocates to the cytoplasm, which leads to the production of reactive oxygen species and neurodegeneration. Carvacrol inhibits transient receptor potential melastatin 7 (TRPM7), which regulates the homeostasis of extracellular metal ions, such as calcium and zinc. In the present study, we test whether carvacrol displays any neuroprotective effects after global cerebral ischemia (GCI), via a blockade of zinc influx. To test our hypothesis, we used eight-week-old male Sprague–Dawley rats, and a GCI model was induced by bilateral common carotid artery occlusion (CCAO), accompanied by blood withdrawal from the femoral artery. Ischemic duration was defined as a seven-minute electroencephalographic (EEG) isoelectric period. Carvacrol (50 mg/kg) was injected into the intraperitoneal space once per day for three days after the onset of GCI. The present study found that administration of carvacrol significantly decreased the number of degenerating neurons, microglial activation, oxidative damage, and zinc translocation after GCI, via downregulation of TRPM7 channels. These findings suggest that carvacrol, a TRPM7 inhibitor, may have therapeutic potential after GCI by reducing intracellular zinc translocation.

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.

scholarly journals Circulating uromodulin inhibits systemic oxidative stress by inactivating the TRPM2 channel

2019 ◽  
Vol 11 (512) ◽  
pp. eaaw3639 ◽  
Author(s):  
Kaice A. LaFavers ◽  
Etienne Macedo ◽  
Pranav S. Garimella ◽  
Camila Lima ◽  
Shehnaz Khan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Transient Receptor Potential ◽  
Kidney Injury ◽  
Receptor Potential ◽  
Underlying Mechanism ◽  
High Serum ◽  
Systemic Oxidative Stress ◽  
Trpm2 Channel ◽  
Poor Outcomes

High serum concentrations of kidney-derived protein uromodulin [Tamm-Horsfall protein (THP)] have recently been shown to be independently associated with low mortality in both older adults and cardiac patients, but the underlying mechanism remains unclear. Here, we show that THP inhibits the generation of reactive oxygen species (ROS) both in the kidney and systemically. Consistent with this experimental data, the concentration of circulating THP in patients with surgery-induced acute kidney injury (AKI) correlated with systemic oxidative damage. THP in the serum dropped after AKI and was associated with an increase in systemic ROS. The increase in oxidant injury correlated with postsurgical mortality and need for dialysis. Mechanistically, THP inhibited the activation of the transient receptor potential cation channel, subfamily M, member 2 (TRPM2) channel. Furthermore, inhibition of TRPM2 in vivo in a mouse model mitigated the systemic increase in ROS during AKI and THP deficiency. Our results suggest that THP is a key regulator of systemic oxidative stress by suppressing TRPM2 activity, and our findings might help explain how circulating THP deficiency is linked with poor outcomes and increased mortality.

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 The Transient Receptor Potential Melastatin 7 (TRPM7) Inhibitors Suppress Seizure-Induced Neuron Death by Inhibiting Zinc Neurotoxicity

2020 ◽  
Vol 21 (21) ◽  
pp. 7897
Author(s):  
Jeong Hyun Jeong ◽  
Song Hee Lee ◽  
A Ra Kho ◽  
Dae Ki Hong ◽  
Dong Hyeon Kang ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Therapeutic Potential ◽  
Divalent Cations ◽  
Neurological Diseases ◽  
Receptor Potential ◽  
Neuron Death ◽  
Intracellular Zinc ◽  
Transient Receptor Potential Melastatin ◽  
Transient Receptor ◽  
Induced Neuron

Transient receptor potential melastatin 7 (TRPM7) is an ion channel that mediates monovalent cations out of cells, as well as the entry of divalent cations, such as zinc, magnesium, and calcium, into the cell. It has been reported that inhibitors of TRPM7 are neuroprotective in various neurological diseases. Previous studies in our lab suggested that seizure-induced neuronal death may be caused by the excessive release of vesicular zinc and the subsequent accumulation of zinc in the neurons. However, no studies have evaluated the effects of carvacrol and 2-aminoethoxydiphenyl borate (2-APB), both inhibitors of TRPM7, on the accumulation of intracellular zinc in dying neurons following seizure. Here, we investigated the therapeutic efficacy of carvacrol and 2-APB against pilocarpine-induced seizure. Carvacrol (50 mg/kg) was injected once per day for 3 or 7 days after seizure. 2-APB (2 mg/kg) was also injected once per day for 3 days after seizure. We found that inhibitors of TRPM7 reduced seizure-induced TRPM7 overexpression, intracellular zinc accumulation, and reactive oxygen species production. Moreover, there was a suppression of oxidative stress, glial activation, and the blood–brain barrier breakdown. In addition, inhibitors of TRPM7 remarkably decreased apoptotic neuron death following seizure. Taken together, the present study demonstrates that TRPM7-mediated zinc translocation is involved in neuron death after seizure. The present study suggests that inhibitors of TRPM7 may have high therapeutic potential to reduce seizure-induced neuron death.

scholarly journals Genetic background influences expression and function of the cation channel TRPM4 in the mouse heart

2020 ◽  
Vol 115 (6) ◽  
Author(s):  
Rebekka Medert ◽  
Andy Pironet ◽  
Lucas Bacmeister ◽  
Sebastian Segin ◽  
Juan E. Camacho Londoño ◽  
...  
Keyword(s):  
Genetic Background ◽  
Transient Receptor Potential ◽  
Cardiac Contractility ◽  
Receptor Potential ◽  
Disease Status ◽  
Mouse Strains ◽  
Mouse Heart ◽  
Transient Receptor Potential Melastatin ◽  
Different Genetic Background

AbstractTransient receptor potential melastatin 4 (TRPM4) cation channels act in cardiomyocytes as a negative modulator of the L-type Ca2+ current. Ubiquitous Trpm4 deletion in mice leads to an increased β-adrenergic inotropy in healthy mice as well as after myocardial infarction. In this study, we set out to investigate cardiac inotropy in mice with cardiomyocyte-specific Trpm4 deletion. The results guided us to investigate the relevance of TRPM4 for catecholamine-evoked Ca2+ signaling in cardiomyocytes and inotropy in vivo in TRPM4-deficient mouse models of different genetic background. Cardiac hemodynamics were investigated using pressure–volume analysis. Surprisingly, an increased β-adrenergic inotropy was observed in global TRPM4-deficient mice on a 129SvJ genetic background, but the inotropic response was unaltered in mice with global and cardiomyocyte-specific TRPM4 deletion on the C57Bl/6N background. We found that the expression of TRPM4 proteins is about 78 ± 10% higher in wild-type mice on the 129SvJ versus C57Bl/6N background. In accordance with contractility measurements, our analysis of the intracellular Ca2+ transients revealed an increase in ISO-evoked Ca2+ rise in Trpm4-deficient cardiomyocytes of the 129SvJ strain, but not of the C57Bl/6N strain. No significant differences were observed between the two mouse strains in the expression of other regulators of cardiomyocyte Ca2+ homeostasis. We conclude that the relevance of TRPM4 for cardiac contractility depends on homeostatic TRPM4 expression levels or the genetic endowment in different mouse strains as well as on the health/disease status. Therefore, the concept of inhibiting TRPM4 channels to improve cardiac contractility needs to be carefully explored in specific strains and species and prospectively in different genetically diverse populations of patients.

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.

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