Abstract 141: Endothelial TRPA1 Channel is Protective Against Ischemia and Hemorrhagic Strokes in Mice

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Paulo W Pires ◽  
Michelle N Sullivan ◽  
Scott Earley
Keyword(s):  
Transient Receptor Potential ◽  
Cerebral Arteries ◽  
Receptor Potential ◽  
Artery Occlusion ◽  
Ros Generation ◽  
Normal Behavior ◽  
Transient Receptor ◽  
Cerebral Artery Occlusion ◽  
And Oxidative Stress ◽  
Specific Deletion

The transient receptor potential ankyrin 1 (TRPA1) cation channel is more selective for Ca 2+ versus Na + ions (∼8:1). We showed that TRPA1 is located in the endothelium of cerebral arteries (eTRPA1) and that reactive oxygen species (ROS)-induced channel activity generates localized Ca 2+ signals (TRPA1 sparklets) that initiate endothelium-dependent hyperpolarization and vasorelaxation. Cerebrovascular disease is associated with increased ROS generation and oxidative stress. Thus, we hypothesized that eTRPA1 activity is protective against stroke. Tissue-specific deletion of eTRPA1 in mice was achieved using the Cre -recombinase (Tie2 promoter) / loxP system. Ischemic strokes were induced by permanent middle cerebral artery occlusion (pMCAO). Neurological function after pMCAO was assessed by a modified neurological severity scale, ranging from 0 to 4 (0: normal behavior; 1: failure to extend contralateral paw; 2: circling; 3: rolling to one side; 4: stupor). Deletion of eTRPA1 increased post-stroke (24 hours) neurological damage in eTRPA1 -/- versus WT mice, as shown by a higher severity score (2.6±0.4 vs 3.8±0.2, p<0.05), and larger infarct size (%hemisphere infarcted: 45±7 vs 62±4%, p0.05, N=8), eTRPA1 -/- mice were significantly more susceptible to hemorrhagic strokes compared to WT. Kaplan-Meyer survival plots showed a higher survival rate for WT vs eTRPA1 -/- at day 10 (61 vs 54%), day 15 (44 vs 21%) and day 20 (22 vs 8%) (p<0.05, N=25). All of the eTRPA1 -/- mice suffered hemorrhagic strokes by day 22, whereas some of the WT mice survived until day 52. Further, eTRPA1 -/- mice showed a higher number of hemorrhagic lesions in the cerebral cortex when compared to WT (12±4 vs 23±4 lesions per animal, p<0.05, N=25 mice per group). These data suggest that eTRPA1 protects against major cerebrovascular accidents and may be considered as a therapeutic target for reducing cerebral infarct after ischemia and as a preventive agent against hemorrhagic strokes.

scholarly journals Cerebral ischemia induces TRPC6 via HIF1α/ZEB2 axis in the glomerular podocytes and contributes to proteinuria

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Krishnamurthy Nakuluri ◽  
Rajkishor Nishad ◽  
Dhanunjay Mukhi ◽  
Sireesh Kumar ◽  
Venkata P. Nakka ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Calcium Influx ◽  
Receptor Potential ◽  
Artery Occlusion ◽  
Ischemic Hypoxia ◽  
Elevated Expression ◽  
Filtration Apparatus ◽  
Transient Receptor ◽  
And Function ◽  
Cerebral Artery Occlusion

AbstractPodocytes are specialized cells of the glomerulus and key component of the glomerular filtration apparatus (GFA). GFA regulates the permselectivity and ultrafiltration of blood. The mechanism by which the integrity of the GFA is compromised and manifest in proteinuria during ischemic stroke remains enigmatic. We investigated the mechanism of ischemic hypoxia-induced proteinuria in a middle cerebral artery occlusion (MCAO) model. Ischemic hypoxia resulted in the accumulation of HIF1α in the podocytes that resulted in the increased expression of ZEB2 (Zinc finger E-box-binding homeobox 2). ZEB2, in turn, induced TRPC6 (transient receptor potential cation channel, subfamily C, member 6), which has increased selectivity for calcium. Elevated expression of TRPC6 elicited increased calcium influx and aberrant activation of focal adhesion kinase (FAK) in podocytes. FAK activation resulted in the stress fibers reorganization and podocyte foot process effacement. Our study suggests overactive HIF1α/ZEB2 axis during ischemic-hypoxia raises intracellular calcium levels via TRPC6 and consequently altered podocyte structure and function thus contributes to proteinuria.

scholarly journals Cerebral ischemia induces TRPC6 in the glomerular podocytes: A novel role for HIF1α/ZEB2 axis in the pathogenesis of stroke-induced proteinuria

2019 ◽  
Author(s):  
Krishnamurthy Nakuluri ◽  
Rajkishor Nishad ◽  
Dhanunjay Mukhi ◽  
Sireesh Kumar ◽  
Venkata P Nakka ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Calcium Influx ◽  
Receptor Potential ◽  
Artery Occlusion ◽  
Ischemic Hypoxia ◽  
Elevated Expression ◽  
Filtration Apparatus ◽  
Foot Process ◽  
Transient Receptor ◽  
Cerebral Artery Occlusion

AbstractGlomerular filtration apparatus (GFA) regulates the glomerular permselectivity and ultrafiltration of urine. Podocytes are specialized cells and a key component of the GFA. The mechanism by which the integrity of the GFA is compromised and manifest in proteinuria during ischemic stroke remains enigmatic. Hypoxia is a determining factor in the pathophysiology of ischemia. We investigated the mechanism of ischemic-hypoxia induced proteinuria in a middle cerebral artery occlusion (MCAO) model. Ischemic hypoxia resulted in the accumulation of HIF1α in the glomerular podocytes that resulted in the increased expression of ZEB2. ZEB2, in turn, induced TRPC6 (transient receptor potential cation channel, subfamily C, member 6), which has increased selectivity for calcium. Elevated expression of TRPC6 elicited increased calcium influx and aberrant activation of focal adhesion kinase (FAK) in podocytes. FAK activation resulted in the stress fibers reorganization and podocyte foot process effacement. Our study suggests overactive HIF1α/ZEB2 axis during ischemic-hypoxia induces intracellular calcium levels via TRPC6 and consequently altered podocyte integrity and permselectivity.

scholarly journals Ischemic Neuroprotection by TRPV1 Receptor-Induced Hypothermia

2012 ◽  
Vol 32 (6) ◽  
pp. 978-982 ◽  
Author(s):  
Mirko Muzzi ◽  
Roberta Felici ◽  
Leonardo Cavone ◽  
Elisabetta Gerace ◽  
Alberto Minassi ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Mild Hypothermia ◽  
Unmet Need ◽  
Receptor Potential ◽  
Artery Occlusion ◽  
Transient Receptor Potential Vanilloid ◽  
Trpv1 Receptor ◽  
Promising Therapeutic Approach ◽  
Transient Receptor ◽  
Cerebral Artery Occlusion

Although treatment of stroke patients with mild hypothermia is a promising therapeutic approach, chemicals inducing prompt and safe reduction of body temperature are an unmet need. We measured the effects of the transient receptor potential vanilloid-1 (TRPV1) agonist rinvanil on thermoregulation and ischemic brain injury in mice. Intraperitoneal or intracerebroventricular injection of rinvanil induces mild hypothermia that is prevented by the receptor antagonist capsazepine. Both intraischemic and postischemic treatments provide permanent neuroprotection in animals subjected to transient middle cerebral artery occlusion (MCAo), an effect lost in mice artificially kept normothermic. Data indicate that TRPV1 receptor agonists are promising candidates for hypothermic treatment of stroke.

PLA2 and TRPV4 channels regulate endothelial calcium in cerebral arteries

2007 ◽  
Vol 292 (3) ◽  
pp. H1390-H1397 ◽  
Author(s):  
Sean P. Marrelli ◽  
Roger G. O'Neil ◽  
Rachel C. Brown ◽  
Robert M. Bryan
Keyword(s):  
Transient Receptor Potential ◽  
Cerebral Arteries ◽  
Receptor Potential ◽  
Ruthenium Red ◽  
Transient Receptor Potential Vanilloid ◽  
Middle Cerebral Arteries ◽  
Trpv Channels ◽  
Intracellular Ca ◽  
Transient Receptor ◽  
Trpv4 Channel

We previously demonstrated that endothelium-derived hyperpolarizing factor (EDHF)-mediated dilations in cerebral arteries are significantly reduced by inhibitors of PLA2. In this study we examined possible mechanisms by which PLA2 regulates endothelium-dependent dilation, specifically whether PLA2 is involved in endothelial Ca2+ regulation through stimulation of TRPV4 channels. Studies were carried out with middle cerebral arteries (MCA) or freshly isolated MCA endothelial cells (EC) of male Long-Evans rats. Nitro-l-arginine methyl ester (l-NAME) and indomethacin were present throughout. In pressurized MCA, luminally delivered UTP produced increased EC intracellular Ca2+ concentration ([Ca2+]i) and MCA dilation. Incubation with PACOCF3, a PLA2 inhibitor, significantly reduced both EC [Ca2+]i and dilation responses to UTP. EC [Ca2+]i was also partially reduced by a transient receptor potential vanilloid (TRPV) channel blocker, ruthenium red. Manganese quenching experiments demonstrated Ca2+ influx across the luminal and abluminal face of the endothelium in response to UTP. Interestingly, PLA2-sensitive Ca2+ influx occurred primarily across the abluminal face. Luminal application of arachidonic acid, the primary product of PLA2 and a demonstrated activator of certain TRPV channels, increased both EC [Ca2+]i and MCA diameter. TRPV4 mRNA and protein was demonstrated in the endothelium by RT-PCR and immunofluorescence, respectively. Finally, application of 4α-phorbol 12,13-didecanoate (4αPDD), a TRPV4 channel activator, produced an increase in EC [Ca2+]i that was significantly reduced in the presence of ruthenium red. We conclude that PLA2 is involved in EC Ca2+ regulation through its regulation of TRPV4 channels. Furthermore, the PLA2-sensitive component of Ca2+ influx may be polarized to the abluminal face of the endothelium.

scholarly journals Chemosensitization of doxorubicin against lung cancer by nature borneol, involvement of TRPM8-regulated calcium mobilization

2020 ◽  
Author(s):  
Haoqiang Lai ◽  
Chang Liu ◽  
Wenwei Lin ◽  
tf Chen ◽  
An Hong
Keyword(s):  
Lung Cancer ◽  
Therapeutic Target ◽  
Transient Receptor Potential ◽  
A549 Cells ◽  
Receptor Potential ◽  
Calcium Mobilization ◽  
Ros Generation ◽  
Transient Receptor Potential Melastatin ◽  
Transient Receptor

Abstract Background Lung cancer possesses high mortality rate and tolerances to multiple chemotherapeutics. Natural Borneol (NB) is a monoterpenoid compound that found to facilitate the bioavailability of drugs. In this study, we attempted to investigate effects of NB on the chemosensitivity in A549 cells and try to elucidate its therapeutic target. Methods The effects of NB on chemosensitivity in A549 cells was examined by MTT assay. The mechanism studies were evaluated by flow cytometry and western blotting assay. Surface plasmon resonance (SPR) and LC-MS combined analysis (MS-SPRi) was performed to elucidate the candidate target of NB contributes to this synergism. The chemosensitizing capacity of NB in vivo was conducted in nude mice bearing A549 tumors. Results NB pretreatment sensitizes A549 cells to low dosage of DOX, leading to a 15.7% to 41.5% increase in apoptosis, which is corelated with ERK and AKT inactivation but activation of phosphor-p38MAPK, -JNK and p53. Furthermore, this synergism depends on reactive oxygen species (ROS) generation. The MS-SPRi analysis reveals that the transient receptor potential melastatin-8 (TRPM8) is the interaction target of NB in potentiating DOX killing potency. Genetically knock down of TRPM8 significantly suppress the chemosensitizing effects of NB with the involvement of inhibiting ROS generation through restraining calcium mobilization. Moreover, pretreatment of NB synergistically enhanced the anticancer effects of DOX to delay tumor progression in vivo. Conclusions These results suggest that TRPM8 may be a valid therapeutic target in the potential application of NB serves as a chemosensitizer for lung cancer treatment.

scholarly journals TRPC3 mediates pyrimidine receptor-induced depolarization of cerebral arteries

2005 ◽  
Vol 288 (5) ◽  
pp. H2055-H2061 ◽  
Author(s):  
S. A. Reading ◽  
S. Earley ◽  
B. J. Waldron ◽  
D. G. Welsh ◽  
J. E. Brayden
Keyword(s):  
Transient Receptor Potential ◽  
Cerebral Arteries ◽  
Receptor Potential ◽  
Receptor Activation ◽  
Antisense Oligodeoxynucleotides ◽  
Canonical Transient Receptor Potential ◽  
Cell Current ◽  
Arterial Smooth Muscle Cells ◽  
Transient Receptor ◽  
Intravascular Pressure

We tested the hypothesis that TRPC3, a member of the canonical transient receptor potential (TRP) family of channels, mediates agonist-induced depolarization of arterial smooth muscle cells (SMCs). In support of this hypothesis, we observed that suppression of arterial SMC TRPC3 expression with antisense oligodeoxynucleotides significantly decreased the depolarization and constriction of intact cerebral arteries in response to UTP. In contrast, depolarization and contraction of SMCs induced by increased intravascular pressure, i.e., myogenic responses, were not altered by TRPC3 suppression. Interestingly, UTP-evoked responses were not affected by suppression of a related TRP channel, TRPC6, which was previously found to be involved in myogenic depolarization and vasoconstriction. In patch-clamp experiments, UTP activated a whole cell current that was greatly reduced or absent in TRPC3 antisense-treated SMCs. These results indicate that TRPC3 mediates UTP-induced depolarization of arterial SMCs and that TRPC3 and TRPC6 may be differentially regulated by receptor activation and mechanical stimulation, respectively.

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