scholarly journals TRPV4-induced Müller cell gliosis and TNF-α elevation-mediated retinal ganglion cell apoptosis in glaucomatous rats via JAK2/STAT3/NF-κB pathway

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Qian Li ◽  
Yun Cheng ◽  
Shenghai Zhang ◽  
Xinghuai Sun ◽  
Jihong Wu
Keyword(s):  
Transient Receptor Potential ◽  
Müller Cell ◽  
Male Rats ◽  
Photopic Negative Response ◽  
Transient Receptor Potential Vanilloid ◽  
Retinal Ganglion ◽  
Tnf Α ◽  
Mechanistic Investigation ◽  
Glaucoma Treatment ◽  
Muller Cell

Abstract Background Glaucoma, the leading cause of irreversible blindness worldwide, is a type of retinal disease characterized by the selective death of retinal ganglion cells (RGCs). However, the pathogenesis of glaucoma has not been fully elucidated. Transient receptor potential vanilloid 4 (TRPV4) is a pressure-sensitive and calcium-permeable cation channel. TRPV4 is widely distributed in the retina and its sustained activation leads to RGC death; indicating that TRPV4 may be a possible target for glaucoma treatment. Here, we investigated the effects of TRPV4 on RGC apoptosis in a rat model of chronic ocular hypertension (COH), then examined the mechanism underlying these effects. Methods The COH model was established by injection of micro-magnetic beads into the anterior chamber of adult male rats. The expression levels of TRPV4, glial fibrillary acidic protein, and inflammatory factors were assessed by immunohistochemistry and immunoblotting. RGC apoptosis and visual dysfunction were evaluated by TUNEL assay and photopic negative response. Functional expression of TRPV4 was examined by electrophysiology and calcium imaging. Real-time polymerase chain reaction and immunoblotting were employed to investigate the molecular mechanism underlying the effects of TRPV4 on tumor necrosis factor-α (TNF-α) release. Results We found that TRPV4 played an essential role in glaucoma, such that high levels of TRPV4 expression were associated with elevated intraocular pressure. Furthermore, TRPV4 activation was involved in glaucoma-induced RGC apoptosis and RGC-related reductions in visual function. Mechanistic investigation demonstrated that TRPV4 activation led to enhanced Müller cell gliosis and TNF-α release via the JAK2/STAT3/NF-kB pathway, while TRPV4 inhibition could reverse these effects. Finally, TRPV4 activation could lead to elevated expression of TNF receptor 1 in RGCs, while inhibition of TNF-α could reduce TRPV4-mediated RGC apoptosis. Conclusions TRPV4 activation induces Müller cell gliosis and TNF-α elevation via the JAK2/STAT3/NF-κB pathway, which may exacerbate RGC apoptosis in glaucoma; these results suggest that TRPV4 can serve as a therapeutic target in glaucoma treatment.

scholarly journals TRPV1 Blocker HCRG21 Suppresses TNF-α Production and Prevents the Development of Edema and Hypersensitivity in Carrageenan-Induced Acute Local Inflammation

Biomedicines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 716
Author(s):  
Oksana Sintsova ◽  
Irina Gladkikh ◽  
Anna Klimovich ◽  
Yulia Palikova ◽  
Viktor Palikov ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Thermal Hyperalgesia ◽  
Control Group ◽  
Transient Receptor Potential Vanilloid ◽  
Paw Edema ◽  
Mice Model ◽  
Edema Formation ◽  
Sensitivity Experiment ◽  
Tnf Α ◽  
Anti Inflammatory

Currently the TRPV1 (transient receptor potential vanilloid type 1) channel is considered to be one of the main targets for pro-inflammatory mediators including TNF-α. Similarly, the inhibition of TRPV1 activity in the peripheral nervous system affects pro-inflammatory mediator production and enhances analgesia in total. In this study, the analgesic and anti-inflammatory effects of HCRG21, the first peptide blocker of TRPV1, were demonstrated in a mice model of carrageenan-induced paw edema. HCRG21 in doses of 0.1 and 1 mg/kg inhibited edema formation compared to the control, demonstrated complete edema disappearance in 24 h in a dose of 1 mg/kg, and effectively reduced the productionof TNF-α in both doses examined. ELISA analysis of blood taken 24 h after carrageenan administration showed a dramatic cytokine value decrease to 25 pg/mL by HCRG21 versus 100 pg/mL in the negative control group, which was less than the TNF-α level in the intact group (40 pg/mL). The HCRG21 demonstrated potent analgesic effects on the models of mechanical and thermal hyperalgesia in carrageenan-induced paw edema. The HCRG21 relief effect was comparable to that of indomethacin taken orally in a dose of 5 mg/kg, but was superior to this nonsteroidal anti-inflammatory drug (NSAID) in duration (which lasted 24 h) in the mechanical sensitivity experiment. The results confirm the existence of a close relationship between TRPV1 activity and TNF-α production once again, and prove the superior pharmacological potential of TRPV1 blockers and the HCRG21 peptide in particular.

Responses of thoracic spinal neurons to activation and desensitization of cardiac TRPV1-containing afferents in rats

2006 ◽  
Vol 291 (6) ◽  
pp. R1700-R1707 ◽  
Author(s):  
Chao Qin ◽  
Jay P. Farber ◽  
Kenneth E. Miller ◽  
Robert D. Foreman
Keyword(s):  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Male Rats ◽  
Transient Receptor Potential Vanilloid ◽  
Spinal Neurons ◽  
Thoracic Spinal ◽  
Afferent Fibers ◽  
Study Results ◽  
Transient Receptor ◽  
Excitatory Responses

The purpose of this study was to examine how upper thoracic spinal neurons responded to activation and desensitization of cardiac transient receptor potential vanilloid-1 (TRPV1)-containing afferent fibers. Extracellular potentials of single T3 spinal neurons were recorded in pentobarbital-anesthetized, paralyzed, and ventilated male rats. To activate cardiac nociceptive receptors, a catheter was placed in the pericardial sac to administer various chemicals: bradykinin (BK; 10 μg/ml, 0.2 ml), capsaicin (CAP, 10 μg/ml, 0.2 ml), or a mixture of algesic chemicals (AC; 0.2 ml) containing adenosine 10−3 M, BK, serotonin, histamine, and PGE2, 10−5 M for each. Spinal neurons that responded to intrapericardial BK and/or CAP were used in this study. Results showed that 81% (35/43) of the neurons had excitatory responses to both intrapericardial BK and CAP, and the remainder responded to either BK or CAP. Intrapericardial resiniferatoxin (RTX) (0.2 μg/ml, 0.2 ml, 1 min), which desensitizes TRPV1-containing nerve endings, abolished excitatory responses to both BK ( n = 8) and CAP ( n = 7), and to AC ( n = 5) but not to somatic stimuli. Intrapericardial capsazepine (1 mg/ml, 0.2 ml, 3 min), a specific antagonist of TRPV1, sharply attenuated excitatory responses to CAP in 5/5 neurons, but responses to BK in 5/5 neurons was maintained. Additionally, intrapericardial capsazepine had no significant effect on excitatory responses to AC in 3/3 neurons. These data indicated that intrapericardial BK-initiated spinal neuronal responses were linked to cardiac TRPV1-containing afferent fibers, but were not dependent on TRPV1. Intraspinal signaling for cardiac nociception was mediated through CAP-sensitive afferent fibers innervating the heart.

scholarly journals Calcium and TRPV4 promote metastasis by regulating cytoskeleton through the RhoA/ROCK1 pathway in endometrial cancer

2020 ◽  
Vol 11 (11) ◽  
Author(s):  
Xingchen Li ◽  
Yuan Cheng ◽  
Zhiqi Wang ◽  
Jingyi Zhou ◽  
Yuanyuan Jia ◽  
...  
Keyword(s):  
Endometrial Cancer ◽  
Cancer Progression ◽  
Transient Receptor Potential ◽  
Calcium Influx ◽  
Biological Significance ◽  
Receptor Potential ◽  
Transient Receptor Potential Vanilloid ◽  
Mechanistic Investigation

AbstractTransient receptor potential vanilloid 4 (TRPV4) is a calcium-permeable cation channel that has been associated with several types of cancer. However, its biological significance, as well as its related mechanism in endometrial cancer (EC) still remains elusive. In this study, we examined the function of calcium in EC, with a specific focus on TRPV4 and its downstream pathway. We reported here on the findings that a high level of serum ionized calcium was significantly correlated with advanced EC progression, and among all the calcium channels, TRPV4 played an essential role, with high levels of TRPV4 expression associated with cancer progression both in vitro and in vivo. Proteomic and bioinformatics analysis revealed that TRPV4 was involved in cytoskeleton regulation and Rho protein pathway, which regulated EC cell migration. Mechanistic investigation demonstrated that TRPV4 and calcium influx acted on the cytoskeleton via the RhoA/ROCK1 pathway, ending with LIMK/cofilin activation, which had an impact on F-actin and paxillin (PXN) levels. Overall, our findings indicated that ionized serum calcium level was significantly associated with poor outcomes and calcium channel TRPV4 should be targeted to improve therapeutic and preventive strategies in EC.

scholarly journals Antinociceptive Effects of Emodin on CFA-Induced Inflammatory Pain in Rats

2020 ◽  
Vol 15 (7) ◽  
pp. 1934578X2094200
Author(s):  
Wan Ni ◽  
Nianyun Wang ◽  
Shenglan Tian ◽  
Qingbang Xu
Keyword(s):  
Mrna Expression ◽  
Inflammatory Pain ◽  
Transient Receptor Potential ◽  
Interleukin 1 ◽  
Receptor Potential ◽  
Enzyme Linked Immunosorbent Assay ◽  
Control Group ◽  
Transient Receptor Potential Vanilloid ◽  
Tnf Α ◽  
Transient Receptor

The effect of emodin on complete Freund’s adjuvant (CFA)-induced inflammatory pain in rats and its potential molecular mechanism was investigated. For this, a rat model of inflammatory pain induced by CFA was established and rats were treated with emodin by intraperitoneal injection. The pain threshold was evaluated by the von Frey, thermo hyperalgesia, and cold plate tests. The mRNA expression of transient receptor potential channel ankyrin type-1 ( Trpa1) and transient receptor potential vanilloid 1 ( Trpv1) was detected by quantitative reverse transcription polymerase chain reaction, and the level of inflammatory cytokines was determined by enzyme-linked immunosorbent assay. The mechanical and thermal pain thresholds of CFA-treated rats were significantly lower than those of the control rats, while the paw withdrawal responses in response to cold stimulation were higher than that of the control group. Emodin treatment significantly improved CFA-induced hyperalgesia. Further results showed that emodin inhibits the upregulation of Trpa1 and Trpv1 mRNA expression in the dorsal root ganglion (DRG) of rats with inflammatory pain compared with the control group. Emodin also significantly reduced the levels of tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), and interleukin 6 (IL-6) in the serum of rats with inflammatory pain. Thus, emodin may inhibit hyperalgesia induced by inflammatory stimulation by downregulating the mRNA expression of Trpa1 and Trpv1 in DRG neurons and reducing the levels of TNF-α, IL-1β, and IL-6.

scholarly journals Glia-Neuron Interactions in the Retina Can Be Studied in Cocultures of Müller Cells and Retinal Ganglion Cells

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
D. M. Skytt ◽  
A. K. Toft-Kehler ◽  
C. T. Brændstrup ◽  
S. Cejvanovic ◽  
I. S. Gurubaran ◽  
...  
Keyword(s):  
Cell Function ◽  
Ganglion Cells ◽  
Glutamate Uptake ◽  
Treatment Strategies ◽  
Müller Cells ◽  
Müller Cell ◽  
Retinal Ganglion ◽  
Muller Cells ◽  
Muller Cell ◽  
The Impact

Glia-neuron partnership is important for inner retinal homeostasis and any disturbances may result in retinal ganglion cell (RGC) death. Müller cells support RGCs with essential functions such as removing excess glutamate and providing energy sources. The aim was to explore the impact of Müller cells on RGC survival. To investigate the Müller cell/RGC interactions we developed a coculture model, in which primary Müller cells were grown in inserts on top of pure primary RGC cultures. The impact of starvation and mitochondrial inhibition on the Müller cell ability to protect RGCs was studied. Moreover, the ability of Müller cells to remove glutamate from the extracellular space was investigated. RGC survival was evaluated by cell viability assays and glutamate uptake was assessed by kinetic uptake assays. We demonstrated a significantly increased RGC survival in presence of untreated and prestarved Müller cells. Additionally, prestarved Müller cells significantly increased RGC survival after mitochondrial inhibition. Finally, we revealed a significantly increased ability to take up glutamate in starved Müller cells. Overall, our study confirms essential roles of Müller cells in RGC survival. We suggest that targeting Müller cell function could have potential for future treatment strategies to prevent blinding neurodegenerative retinal diseases.

scholarly journals Activated Müller Cells Involved in ATP-Induced Upregulation of P2X7Receptor Expression and Retinal Ganglion Cell Death

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Ying Xue ◽  
Yuting Xie ◽  
Bo Xue ◽  
Nan Hu ◽  
Guowei Zhang ◽  
...  
Keyword(s):  
Protein Expression ◽  
Ganglion Cell ◽  
Intravitreal Injection ◽  
Retinal Ganglion Cell ◽  
Cell Activation ◽  
Müller Cells ◽  
Müller Cell ◽  
Retinal Ganglion ◽  
Muller Cells ◽  
Muller Cell

P2X7receptor (P2X7R), an ATP-gated ion channel, plays an important role in glaucomatous retinal ganglion cell (RGC) apoptotic death, in which activated retinal Müller glial cells may be involved by releasing ATP. In the present study, we investigated whether and how activated Müller cells may induce changes in P2X7R expression in RGCs by using immunohistochemistry and Western blot techniques. Intravitreal injection of DHPG, a group I metabotropic glutamate receptor (mGluR I) agonist, induced upregulation of GFAP expression, suggestive of Müller cell activation (gliosis), as we previously reported. Accompanying Müller cell activation, P2X7R protein expression was upregulated, especially in the cells of ganglion cell layer (GCL), which was reversed by coinjection of brilliant blue G (BBG), a P2X7R blocker. In addition, intravitreal injection of ATP also induced upregulation of P2X7R protein expression. Similar results were observed in cultured retinal neurons by ATP treatment. Moreover, both DHPG and ATP intravitreal injection induced a reduction in the number of fluorogold retrogradely labeled RGCs, and the DHPG effect was partially rescued by coinjection of BBG. All these results suggest that activated Müller cells may release ATP and, in turn, induce upregulation of P2X7R expression in the cells of GCL, thus contributing to RGC death.

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