Hydrogen sulfide modulates IL-6/STAT3 pathway and inhibits oxidative stress, inflammation, and apoptosis in rat model of methotrexate hepatotoxicity

2019 ◽  
Vol 39 (1) ◽  
pp. 77-85 ◽  
Author(s):  
AA Fouad ◽  
HM Hafez ◽  
AAH Hamouda

Methotrexate (MTX) is a commonly used anticancer and immunosuppressive agent. However, MTX can induce hepatotoxicity due to oxidative stress, inflammation, and apoptosis. Hydrogen sulfide (H2S), the endogenous gaseous molecule, has antioxidant, anti-inflammatory, and anti-apoptotic effects. The present work explored the probable protective effect of H2S against MTX hepatotoxicity in rats and also the possible mechanisms underlying this effect. MTX was given at a single intraperitoneal (i.p.) dose of 20 mg/kg. Sodium H2S (56 µmol /kg/day, i.p.), as H2S donor, was given for 10 days, starting 6 days before MTX administration. H2S significantly reduced serum alanine aminotransferase, hepatic malondialdehyde, interleukin 6, nuclear factor κB p65, cytosolic cytochrome c, phosphorylated signal transducer and activator of transcription 3, and Bax/Bcl-2 ratio and significantly increased hepatic total antioxidant capacity and endothelial nitric oxide synthase (eNOS) in rats received MTX. In addition, H2S minimized the histopathological injury and significantly decreased the expression of STAT3 in liver tissue of MTX-challenged rats. The effects of H2S were significantly antagonized by administration of glibenclamide as KATP channel blocker, Nω-nitro-l-arginine, as eNOS inhibitor, or ruthenium red, as transient receptor potential vanilloid 1 (TRPV1) antagonist. It was concluded that H2S provided significant hepatoprotection in MTX-challenged rats through its antioxidant, anti-inflammatory, anti-apoptotic effects. These effects are most probably mediated by the ability of H2S to act as IL-6/STAT3 pathway modulator, KATP channel opener, eNOS activator, and TRPV1 agonist.

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Igor Blaha ◽  
María Elvira López-Oliva ◽  
María Pilar Martínez ◽  
Paz Recio ◽  
Ángel Agis-Torres ◽  
...  

Purpose. This study investigates whether functionality and/or expression changes of transient receptor potential vanilloid 1 (TRPV1) and transient receptor potential ankyrin 1 (TRPA1) channels, oxidative stress, and hydrogen sulfide (H2S) are involved in the bladder dysfunction from an insulin-resistant obese Zucker rat (OZR). Materials and Methods. Detrusor smooth muscle (DSM) samples from the OZR and their respective controls, a lean Zucker rat (LZR), were processed for immunohistochemistry for studying the expression of TRPA1 and TRPV1 and the H2S synthase cystathionine beta-synthase (CBS) and cysthathionine-γ-lyase (CSE). Isometric force recordings to assess the effects of TRPA1 agonists and antagonists on DSM contractility and measurement of oxidative stress and H2S production were also performed. Results. Neuronal TRPA1 expression was increased in the OZR bladder. Electrical field stimulation- (EFS-) elicited contraction was reduced in the OZR bladder. In both LZR and OZR, TRPA1 activation failed to modify DSM basal tension but enhanced EFS contraction; this response is inhibited by the TRPA1 blockade. In the OZR bladder, reactive oxygen species, malondialdehyde, and protein carbonyl contents were increased and antioxidant enzyme activities (superoxide dismutase, catalase, GR, and GPx) were diminished. CSE expression and CSE-generated H2S production were also reduced in the OZR. Both TRPV1 and CBS expressions were not changed in the OZR. Conclusions. These results suggest that an increased expression and functionality of TRPA1, an augmented oxidative stress, and a downregulation of the CSE/H2S pathway are involved in the impairment of nerve-evoked DSM contraction from the OZR.


2018 ◽  
Vol 19 (11) ◽  
pp. 3543 ◽  
Author(s):  
Jeong Baek ◽  
Jae Jeong ◽  
Kyoung Kim ◽  
So-Yoon Won ◽  
Young Chung ◽  
...  

We demonstrated that capsaicin (CAP), an agonist of transient receptor potential vanilloid subtype 1 (TRPV1), inhibits microglia activation and microglia-derived oxidative stress in the substantia nigra (SN) of MPP+-lesioned rat. However, the detailed mechanisms how microglia-derived oxidative stress is regulated by CAP remain to be determined. Here we report that ciliary neurotrophic factor (CNTF) endogenously produced by CAP-activated astrocytes through TRPV1, but not microglia, inhibits microglial activation and microglia-derived oxidative stress, as assessed by OX-6 and OX-42 immunostaining and hydroethidine staining, respectively, resulting in neuroprotection. The significant increase in levels of CNTF receptor alpha (CNTFRα) expression was evident on microglia in the MPP+-lesioned rat SN and the observed beneficial effects of CNTF was abolished by treatment with CNTF receptor neutralizing antibody. It is therefore likely that CNTF can exert its effect via CNTFRα on microglia, which rescues dopamine neurons in the SN of MPP+-lesioned rats and ameliorates amphetamine-induced rotations. Immunohistochemical analysis revealed also a significantly increased expression of CNTFRα on microglia in the SN from human Parkinson’s disease patients compared with age-matched controls, indicating that these findings may have relevance to the disease. These data suggest that CNTF originated from TRPV1 activated astrocytes may be beneficial to treat neurodegenerative disease associated with neuro-inflammation such as Parkinson’s disease.


2007 ◽  
Vol 292 (3) ◽  
pp. H1390-H1397 ◽  
Author(s):  
Sean P. Marrelli ◽  
Roger G. O'Neil ◽  
Rachel C. Brown ◽  
Robert M. Bryan

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.


2006 ◽  
Vol 291 (3) ◽  
pp. R541-R550 ◽  
Author(s):  
Dan Ni ◽  
Qihai Gu ◽  
Hong-Zhen Hu ◽  
Na Gao ◽  
Michael X. Zhu ◽  
...  

A recent study has demonstrated that increasing the intrathoracic temperature from 36°C to 41°C induced a distinct stimulatory and sensitizing effect on vagal pulmonary C-fiber afferents in anesthetized rats ( J Physiol 565: 295–308, 2005). We postulated that these responses are mediated through a direct activation of the temperature-sensitive transient receptor potential vanilloid (TRPV) receptors by hyperthermia. To test this hypothesis, we studied the effect of increasing temperature on pulmonary sensory neurons that were isolated from adult rat nodose/jugular ganglion and identified by retrograde labeling, using the whole cell perforated patch-clamping technique. Our results showed that increasing temperature from 23°C (or 35°C) to 41°C in a ramp pattern evoked an inward current, which began to emerge after exceeding a threshold of ∼34.4°C and then increased sharply in amplitude as the temperature was further increased, reaching a peak current of 173 ± 27 pA ( n = 75) at 41°C. The temperature coefficient, Q10, was 29.5 ± 6.4 over the range of 35–41°C. The peak inward current was only partially blocked by pretreatment with capsazepine (Δ I = 48.1 ± 4.7%, n = 11) or AMG 9810 (Δ I = 59.2 ± 7.8%, n = 8), selective antagonists of the TRPV1 channel, but almost completely abolished (Δ I = 96.3 ± 2.3%) by ruthenium red, an effective blocker of TRPV1–4 channels. Furthermore, positive expressions of TRPV1–4 transcripts and proteins in these neurons were demonstrated by RT-PCR and immunohistochemistry experiments, respectively. On the basis of these results, we conclude that increasing temperature within the normal physiological range can exert a direct stimulatory effect on pulmonary sensory neurons, and this effect is mediated through the activation of TRPV1, as well as other subtypes of TRPV channels.


2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Xiaoqian Gao ◽  
Sheryl Koch ◽  
Min Jiang ◽  
Nathan Robbins ◽  
Wenfeng Cai ◽  
...  

TRPV2 is a member of transient receptor potential vanilloid (TRPV) family. As a Ca 2+ channel, it can detect various stimuli such as noxious heat (>52°C), membrane stretching, as well as a number of exogenous chemicals, including probenecid, 2-aminoethoxydiphenyl borate, and lysophospholipids. TRPV2 has been found in many tissue types, including neuron and kidney, but the function of TRPV2 in the heart is poorly understood. Here we show TRPV2 is involved in the Ca 2+ cycling process and then regulates the function of the cardiomyocyte. We identified the mRNA expression of TRPV2 in the cardiac tissues of mice using real-time PCR. By performing echocardiography we found that administration of probenecid, a selective TRPV2 agonist, increased cardiac ejection fraction in mice. This positive inotropic effect of probenecid was also shown in Langendorff perfused mice hearts as increased peak +dP/dt. In isolated ventricular myocytes, we found that probenecid significantly increased myocyte fractional shortening in a dose-dependent manner, which was fully blocked by ruthenium red, a non-selective TRPV2 blocker. We also performed fluorescent studies to examine myocyte Ca 2+ cycling. We found that probenecid significantly increased Ca 2+ transient and resting-state Ca 2+ sparks and this effect was eliminated by ruthenium red. When Ca 2+ storage in sarcoplasmic reticulum (SR) was depleted with caffeine, and SR Ca 2+ reuptake was blocked by thapsigargin at the same time, probenecid did not show any effects in either Ca 2+ transient or Ca 2+ sparks. Our patch clamp experiments indicate that probenecid treatment does not trigger any significant transmembrane Ca 2+ influx. These results point to the important role of TRPV2 in regulating SR Ca 2+ release. In conclusion, TRPV2 activation may contribute to increased SR Ca 2+ release, leading to the enhancement of myocyte contractility. Thus, TRPV2 plays a potentially important role in controlling the cellular function of heart.


Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Beihua Zhong ◽  
Donna H Wang

Impairment of function and expression of the transient receptor potential vanilloid type 1 (TRPV1) occurs in obesity and diabetes, which may aggravate inflammation and tissue injury given that the TRPV1 mediated pathway has been shown to be anti-inflammatory. Glucagon-like peptide-1 (GLP-1), an incretin hormone released in response to food intake, is capable of protecting tissues from injury, but its mechanism largely unknown. We tested the hypothesis that exendin-4 (Ex4), a GLP-1 receptor agonist, suppresses hypoxia-induced cytokine release via a TRPV1 mediated pathway. Using gene-targeted TRPV1-null mutant (TRPV1 -/- ) or wild-type (WT, C57BL/6) mice, plasma creatinine or urine lactate dehydrogenase (LDH) levels were measured 40- min after ischemia plus 3-hr reperfusion (I/R). Renal I/R increased plasma creatinine and urine LDH levels with a greater magnitude in TRPV1-/- than WT mice (creatinine, uM: WT: 99.4 ± 4.4 to TRPV1: 129.7 ± 11.9, p < 0.05; LDH, mU: WT: 132.3± 39.8 to TRPV1-/-: 178.5 ± 44.4, p < 0.05). In vitro, cytokine or chemokine secretion from renal tissues incubated either with 95% O 2 -5% CO 2 or 99% nitrogen (hypoxia) was measured. TNFα, IL-6, or MCP-1 release in response to nitrogen (1 hr) was increased in both strains with a bigger magnitude in TRPV1-/- than WT mice (p<0.05). Blockade of receptors for calcitonin gene-related peptide (CGRP) with CGRP8-38 (10 -7 M) further increased hypoxia-induced MCP-1 release in WT mice (p<0.05). Ex4 suppressed nitrogen (0.5hr)-induced cytokine/chemokine release from the kidneys in WT but not TRPV1-/-mice (WT: IL-6: 0.74 ± 0.08 to 0.66 ± 0.03; TNF-a: 0.73 ± 0.07 to 0.66 ± 0.03; MCP-1: 16.1± 3.5 to 12.7 ± 1.3 pg/g/min, p < 0.05. TRPV1-/-: p>0.05 for all). Moreover, Ex4 increased CGRP release from the renal pelvis in WT ( p < 0.05) but not TRPV1 -/- mice, which can be inhibited by Ex9-39, an Ex4 antagonist. Thus, ablation of TRPV1 or blockade of CGRP receptors enhances hypoxia-induced inflammation and renal injury following I/R. Ex4 suppresses hypoxia-induced cytokine/chemokine release and enhances CGRP release from the kidney only when TRPV1 function and expression are intact, suggesting that TRPV1/CGRP may play a key role mediating Ex4-induced anti-inflammatory effects.


Cell Cycle ◽  
2012 ◽  
Vol 11 (2) ◽  
pp. 343-349 ◽  
Author(s):  
Samuel P. Wanner ◽  
Andras Garami ◽  
Eszter Pakai ◽  
Daniela L. Oliveira ◽  
Narender R. Gavva ◽  
...  

2014 ◽  
Vol 307 (6) ◽  
pp. F666-F672 ◽  
Author(s):  
Pablo D. Cabral ◽  
Jeffrey L. Garvin

Nitric oxide (NO) regulates renal function. Luminal flow stimulates NO production in the thick ascending limb (TAL). Transient receptor potential vanilloid 4 (TRPV4) is a mechano-sensitive channel activated by luminal flow in different types of cells. We hypothesized that TRPV4 mediates flow-induced NO production in the rat TAL. We measured NO production in isolated, perfused rat TALs using the fluorescent dye DAF FM. Increasing luminal flow from 0 to 20 nl/min stimulated NO from 8 ± 3 to 45 ± 12 arbitrary units (AU)/min ( n = 5; P < 0.05). The TRPV4 antagonists, ruthenium red (15 μmol/l) and RN 1734 (10 μmol/l), blocked flow-induced NO production. Also, luminal flow did not increase NO production in the absence of extracellular calcium. We also studied the effect of luminal flow on NO production in TALs transduced with a TRPV4shRNA. In nontransduced TALs luminal flow increased NO production by 47 ± 17 AU/min ( P < 0.05; n = 5). Similar to nontransduced TALs, luminal flow increased NO production by 39 ± 11 AU/min ( P < 0.03; n = 5) in TALs transduced with a control negative sequence-shRNA while in TRPV4shRNA-transduced TALs, luminal flow did not increase NO production (Δ10 ± 15 AU/min; n = 5). We then tested the effect of two different TRPV4 agonists on NO production in the absence of luminal flow. 4α-Phorbol 12,13-didecanoate (1 μmol/l) enhanced NO production by 60 ± 11 AU/min ( P < 0.002; n = 7) and GSK1016790A (10 ηmol/l) increased NO production by 52 ± 15 AU/min ( P < 0.03; n = 5). GSK1016790A (10 ηmol/l) did not stimulate NO production in TRPV4shRNA-transduced TALs. We conclude that activation of TRPV4 channels mediates flow-induced NO production in the rat TAL.


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