Chronic exposure of sensory neurones to increased levels of nerve growth factor modulates CB1/TRPV1 receptor crosstalk

BACKGROUND: Anandamide (AEA) activates both cannabinoid CB(1) and TRPV1 receptors, which are expressed on cultured dorsal root ganglion neurones. Increased levels of nerve growth factor (NGF) are associated with chronic pain states. EXPERIMENTAL APPROACH: The aim of this study was to compare of the effects of AEA on CB(1) receptor signalling and TRPV1-CB(1) crosstalk in low and high concentrations of NGF, using voltage-clamp electrophysiology and Fura-2 calcium imaging. KEY RESULTS: Chronic exposure to high NGF (200 ng ml(-1)) as compared to low NGF (20 ng ml(-1)) increases the proportion of neurones that exhibit an inward current in response to AEA (1 microM), from 7 to 29%. In contrast, inhibition of voltage-gated calcium currents by AEA is not significantly different in low NGF (33+/-9%, compared to high NGF 28+/-6%). Crosstalk between CB and TRPV1 receptors is modulated by exposure to high NGF. In low NGF, exposure to the CB(1) receptor antagonist, SR141716A, (100 nM) increases the percentage of neurones in which AEA elicits an increase in [Ca(2+)](i), from 10 to 23%. In high NGF, the antagonist does not alter the percentage of responders (33 to 30%). In low NGF, exposure to the CB receptor agonist, WIN55 (1 microM) reduces capsaicin-mediated increases in [Ca(2+)](i) to 28+/-8% of control as compared to an enhancement to 172+/-26% of control observed in high NGF. CONCLUSIONS AND IMPLICATIONS: We conclude that cannabinoid-mediated modulation of TRPV1 receptor activation is altered after exposure to high NGF.     

TRPV1和TRPV4通道参与缺血/氧处理心血管保护的研究进展

TRPV通道属于瞬时受体电位(transient receptor potential,TRP)通道,含有TRPV1、TRPV2、TRPV3、TR-PV4、TRPV5和TRPV6等多种亚型,它们参与机体痛觉、味觉、体温等多种生理机能的调控.近期研究发现TRPV1和TRPV4通道可能参与缺血/氧处理诱导的心肌与血管保护.TRPV1通道的作用机制可能与降钙素基因相关肽(CGRP)及P物质的释放、花生四烯酸脂氧合酶(ALOX)的表达增多有关;TRPV4通道介导的血管保护机制可能与NO和EDHF介导的内皮源性舒张有关.本文将对TRPV1和TRPV4通道在不同形式缺血/氧处理诱导下的心血管保护机制进行综述,以期为心肌缺血的治疗提供新方向.     

2-Aminoethoxydiphenyl borate as a common activator of TRPV1, TRPV2, and TRPV3 channels

2-Aminoethoxydiphenyl borate (2APB) had been depicted as a universal blocker of transient receptor potential (TRP) channels. While evidence has accumulated showing that some TRP channels are indeed inhibited by 2APB, especially in heterologous expression systems, there are other TRP channels that are unaffected or affected very little by this compound. More interestingly, the thermosensitive TRPV1, TRPV2, and TRPV3 channels are activated by 2APB. This has been demonstrated both in heterologous systems and in native tissues that express these channels. A number of 2APB analogs have been examined for their effects on native store-operated channels and heterologously expressed TRPV3. These studies revealed a complex mechanism of action for 2APB and its analogs on ion channels. In this review, we have summarized the current results on 2APB-induced activation of TRPV1-3 and discussed the potential mechanisms by which 2APB may regulate TRP channels.     

脊髓损伤大鼠膀胱顺应性与神经生长因子表达的相关性研究

目的探讨大鼠脊髓不同部位损伤后膀胱顺应性与膀胱神经生长因子(NGF)表达的关系。方法180只雌性SD大鼠按随机数字表分成3组,胸腰段损伤组60只,骶段损伤组60只,正常对照组60只。使用标准化脊髓损伤动物模型实验装置制备背侧脊髓损伤动物模型,胸腰段损伤组损伤部位为T10~L1,骶段损伤组损伤部位为S2-S4,对照组大鼠仅咬除棘突和椎板,不损伤脊髓。4周后作膀胱测压检测后,取出膀胱制备组织匀浆,酶联免疫吸附试验(ELISA)法测定NGF的表达量。结果 1胸腰段损伤组以低顺应性膀胱为特征,骶段损伤组表现为高顺应性膀胱。2膀胱组织ELISA检测结果表明:胸腰段损伤组膀胱组织NGF表达量增加,骶段损伤组膀胱组织NGF表达量降低。3胸腰段脊髓损伤后膀胱顺应性和膀胱组织中NGF表达量呈负相关(r=-0.655,P<0.05);骶段脊髓损伤后膀胱顺应性和膀胱组织中NGF表达量呈负相关(r=-0.783,P<0.05)。结论脊髓高位损伤后膀胱顺应性降低,膀胱组织NGF表达量升高;脊髓低位损伤后膀胱顺应性升高,膀胱组织NGF表达量降低;脊髓损伤后膀胱顺应性的改变与NGF的表达量呈负相关。     

Prostanoid-dependent bladder pain caused by proteinase-activated receptor-2 activation in mice: Involvement of TRPV1 and T-type Ca2+ channels

We studied the pronociceptive role of proteinase-activated receptor-2 (PAR2) in mouse bladder. In female mice, intravesical infusion of the PAR2-activating peptide, SLIGRL-amide (SL), caused delayed mechanical hypersensitivity in the lower abdomen, namely ‘referred hyperalgesia’, 6–24 h after the administration. The PAR2-triggered referred hyperalgesia was prevented by indomethacin or a selective TRPV1 blocker, and restored by a T-type Ca²⁺ channel blocker. In human urothelial T24 cells, SL caused delayed prostaglandin E₂ production and COX-2 upregulation. Our data suggest that luminal PAR2 stimulation in the bladder causes prostanoid-dependent referred hyperalgesia in mice, which involves the activation of TRPV1 and T-type Ca²⁺ channels.     

柴胡疏肝散对糖尿病周围神经病变大鼠瞬时受体电位香草酸亚型1/降钙素基因相关肽通路及坐骨神经电生理变化的影响

目的 探究柴胡疏肝散对糖尿病周围神经病变（DPN）大鼠瞬时受体电位香草酸亚型1(TRPV1)/降钙素基因相关肽（CGRP）通路及坐骨神经电生理变化的影响。方法 2019年12月至2020年9月,从北京生命科学研究所动物实验中心购入SD大鼠,采用高脂饲料+小剂量链脲佐菌素（STZ）腹腔注射法建立DPN大鼠模型,分为对照组、模型组、弥可保组（175μg/kg）、低中高剂量柴胡疏肝散（3.15、6.30、12.60 g/kg）,每组5只,造模成功后,连续给药8周。8周末检测各组大鼠摆尾温度阈值,肌电图仪检测大鼠运动神经传导速度（MNCV）及其支配肌复合运动动作电位的波幅（AMP）、潜伏期（LAT）的变化。实时荧光定量PCR(qRT-PCR)法检测血清TRPV1、CGRP、肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)mRNA的水平;苏木精-伊红（HE）染色观察坐骨神经组织病理变化;蛋白质印迹法检测坐骨神经组织中TRPV1、CGRP、TNF-α、IL-1β蛋白水平。结果 与对照组[（33.15±1.28）s、（1.37±0.06）ms、（41.48±5.36）m/s、（12.3...     

Modulation of urinary bladder innervation: TRPV1 and botulinum toxin A

The persisting interest around neurotoxins such as vanilloids and botulinum toxin (BoNT) derives from their marked effect on detrusor overactivity refractory to conventional antimuscarinic treatments. In addition, both are administered by intravesical route. This offers three potential advantages. First, intravesical therapy is an easy way to provide high concentrations of pharmacological agents in the bladder tissue without causing unsuitable levels in other organs. Second, drugs effective on the bladder, but inappropriate for systemic administration, can be safely used as it is the case of vanilloids and BoNT. Third, the effects of one single treatment might be extremely longlasting, contributing to render these therapies highly attractive to patients despite the fact that the reasons to the prolonged effect are still incompletely understood. Attractive as it may be, intravesical pharmacological therapy should still be considered as a second-line treatment in patients refractory to conventional oral antimuscarinic therapy or who do not tolerate its systemic side effects. However, the increasing off-label use of these neurotoxins justifies a reappraisal of their pharmacological properties.     

Pyocyanin induces systemic oxidative stress,inflammation and behavioral changes in vivo

Pyocyanin (PCN) is a virulence factor secreted by Pseudomonas aeruginosa (P. aeruginosa) that has been shown to have numerous toxic effects in both in vitro and in vivo studies. Such toxicities include pro-inflammatory and pro-oxidant mediated responses. It is hypothesized that PCN can cross biological membranes and reach the systemic circulation, but no previous studies have investigated this. The aim of this study was, therefore, to quantify PCN in plasma and assess if systemic responses were occurring after localized intranasal administration in C57BL/6?J mice. This was achieved through the plasma quantification of PCN and assessment of changes to behavior using two commonly used tests, the forced swimming test and the open field test. Furthermore, evidence of systemic oxidative stress and inflammation was measured using malondialdehyde (MDA) and TNF-α post PCN exposure. PCN was found to cross into systemic circulation but in a variable manner. Furthermore, significant increases in plasma TNF-α and MDA (both p?相似文献   

周围神经缺血后相关神经元凋亡及神经生长因子动态变化的研究

目的探讨大鼠坐骨神经缺血后相关脊髓节段和背根节神经元的凋亡及神经生长因子（NGF）表达的变化,以期为周围神经缺血性神经病的机制及临床治疗提供理论依据。方法结扎大鼠单侧髂总动脉制作坐骨神经缺血模型,分别于术后3、5、7、14、21、28d用4%多聚甲醛灌流固定,取腰髓L4～6节段和双侧第4～6腰脊神经节固定,分别进行免疫组织化学及TUNEL染色检测神经元的NGF和凋亡表达,同体对照。结果坐骨神经缺血的不同时间段L4～6脊髓前角运动神经元及背根节神经元可见凋亡神经元细胞,背根节神经元凋亡率术后3d时显著性升高,术后7d时达到峰值后缓慢下降,后期接近对照侧水平。腰髓前角运动神经元在术后5d时开始有显著性提高,14d时达到最大值后逐渐下降,后期较对照侧仍显著性增高。腰髓前角运动神经元及背根节神经元NGF的表达5d时阳性率较对照侧开始显著降低,7d时达到最低点后逐渐复原,至术后28d时与对照侧无明显差异。结论周围神经缺血性损伤导致相关神经元胞体中NGF含量减少,与神经元凋亡相关。缺血性损伤对背根节感觉神经元的影响较脊髓运动神经明显。     

Disease-related changes in TRPV1 expression and its implications for drug development

The transient receptor potential vanilloid 1 (TRPV1) channel has been a topic of great interest, since its discovery in 1997. It is a homotetrameric non-selective cation channel predominantly expressed in a population of sensory neurons and its involvement in different modalities of pain has been extensively studied. However, TRPV1 has also been shown to be expressed in non-sensory neurons and non-neuronal cells. TRPV1 is considered as a potential target for drug development, based on its tissue distribution and its role in physiological functions. Here, we summarize the evidences for disease-related alterations in TRPV1 expression and function and review the current perspectives for the therapeutic potential of TRPV1 agonists and antagonists in the treatment of a wide range of diseases.     

Nerve growth factor and its receptors in asthma and inflammation

Nerve growth factor (NGF) is a high molecular weight peptide that belongs to the neurotrophin family. It is synthesized by various structural and inflammatory cells and activates two types of receptors, the TrkA (tropomyosin-receptor kinase A) receptor and the p75^NTR receptor, in the death receptor family. NGF was first studied for its essential role in neuronal growth and survival. Recent reports indicate that it may also help mediate inflammation, especially in the airways. Several studies in animals have reported that NGF may induce bronchial hyperresponsiveness, an important feature of asthma, by increasing sensory innervation. It may also induce migration and activation of inflammatory cells, which infiltrate the bronchial mucosa, and of structural cells, including epithelial, smooth muscle cells and pulmonary fibroblasts. Increased NGF expression and release is observed in asthma patients after bronchial provocation with allergen. Taken together, the data from the literature suggest that NGF may play a role in inflammation, bronchial hyperresponsiveness and airway remodelling in asthma and may help us to understand the neuro-immune cross-talk involved in chronic inflammatory airway diseases.     

Cytotoxic effects of acrylamide in nerve growth factor or fibroblast growth factor 1-induced neurite outgrowth in PC12 cells

Acrylamide is a neurological and reproductive toxicant in humans and laboratory animals; however, the neuron developmental toxicity of acrylamide remains unclear. The aims of this study are to investigate the cytotoxicity and neurite outgrowth inhibition of acrylamide in nerve growth factor (NGF)- or fibroblast growth factor 1 (FGF1)-mediated neural development of PC12 cells. MTS assay showed that acrylamide treatment suppresses NGF- or FGF1-induced PC12 cell proliferation in a time- and dose-dependent manner. Quantification of neurite outgrowth demonstrated that 0.5 mM acrylamide treatment resulted in significant decrease in differentiation of NGF- or FGF1-stimulated PC12 cells. This decrease is accompanied with the reduced expression of growth-associated protein-43, a neuronal marker. Moreover, relative levels of pERK, pAKT, pSTAT3 and pCREB were increased within 5–10 min when PC12 cells were treated with NGF or FGF1. Acrylamide (0.5 mM) decreases the NGF-induced activation of AKT–CREB but not ERK–STAT3 within 20 min. Similarly, acrylamide (0.5 mM) decreases the FGF1-induced activation of AKT–CREB within 20 min. In contrast to the NGF treatment, the ERK–STAT3 activation that was induced by FGF1 was slightly reduced by 0.5 mM acrylamide. We further showed that PI3K inhibitor (LY294002), but not MEK inhibitor (U0126), could synergize with acrylamide (0.5 mM) to reduce the cell viability and neurite outgrowth in NGF- or FGF1-stimulated PC12 cells. Moreover, acrylamide (0.5 mM) increased reactive oxygen species (ROS) activities in NGF- or FGF1-stimulated PC12 cells. This increase was reversed by Trolox (an ROS scavenging agent) co-treatment. Together, our findings reveal that NGF- or FGF1-stimulation of the neuronal differentiation of PC12 cells is attenuated by acrylamide through the inhibition of PI3K–AKT–CREB signaling, along with the production of ROS.     

Oral administration of idebenone induces nerve growth factor in the brain and improves learning and memory in basal forebrain-lesioned rats

Nerve growth factor plays an important role in the survival and maintenance of cholinergic neurons in the central neuronal system. In senile dementia of the Alzheimer type, learning and memory are impaired by the loss of neurons in the magnocellular cholinergic neuronal system. It is, therefore, of interest to investigate the role of nerve growth factor in this degenerative disorder. Since nerve growth factor does not cross the blood-brain barrier and is easily metabolized by peptidases when administered peripherally, it can be used for medical treatment only when directly injected into the brain.We demonstrate here that the oral administration of idebenone, a potent in vitro nerve growth factors synthesis stimulator, induced an increase in nerve growth factor protein and mRNA, and in choline acetyltransferase activity, in basal forebrain lesioned rats, but not in intact rats. Idebenone also ameliorated the behaviroral deficits in habituation, water maze, and passive avoidance tasks in these animals.These results suggest that idebenone stimulated nerve growth factor synthesis in vivo and ameliorates the behavioral defitics which were accompanied with the recovery of the reduced choline acetyltransferase activity in the basal forebrain-lesioned rats. Correspondence to. T. Nabeshima at the above address     

HMGA2与DNMT1在膀胱尿路上皮癌中的表达及临床意义

目的探讨HMGA2与DNMTl在膀胱尿路上皮癌中的表达变化及临床意义。方法利用免疫组化方法,以膀胱尿路上皮患者的癌组织及正常人的膀胱组织为研究对象,比较两组患者膀胱组织HMGA2与DNMTl的蛋白的表达水平变化。结果HMGA2与DNMTl在膀胱尿路上皮癌组织中的阳性表达率分别为65．00％和60．00％,与相对应的对照的正常膀胱组织相比较,HMGA2与DNMTl的表达增高显著,具有显著的统计学差异（P〈0．05）。结论HMGA2与DNMTl基因在膀胱尿路上皮癌的组织当中的过量表达,通过检测和干扰HM-GA2与DNMTl基因可能为膀胱尿路上皮的早期诊断和制定治疗方案提供新依据。     

Sulodexide induces hepatocyte growth factor release in humans

Heparin influences numerous pleiotropic growth factors, including hepatocyte growth factor (HGF), partially by their release from endothelial and extracellular matrix stores. The effects of sulodexide, a heparin-like glycosaminoglycan medication of growing importance in medicine, on HGF liberation are not known. We performed a 2-week open-label sulodexide trial in healthy male volunteers. The drug was initially administered intravenously (i.v.) in a single dose of 1200 Lipoprotein Lipase Releasing Units (LRU), then -- orally for 12 days (500 LRU twice a day), and -- again by i.v. route (1200 LRU) on day 14. Intravenous sulodexide injections were repeatedly found to induce marked and reproducible increases in immunoreactive plasma HGF levels (more than 3500% vs baseline after 10 min, and more than 1200% after 120 min), and remained unchanged when measured 120 min following oral sulodexide administration. The percentage increments in plasma HGF evoked by i.v. sulodexide at both time points and on both days inversely correlated with baseline levels of the growth factor. On day 14, the HGF levels after 120 min and their percentage increase vs baseline were strongly and directly dependent on i.v. sulodexide dose per kg of body weight. This study shows that sulodexide has a novel, remarkable and plausibly biologically important stimulating effect on the release of pleiotropic hepatocyte growth factor in humans.     

Effects of morphine on oedema and tissue concentration of nerve growth factor in experimental inflammation of the rat paw

Injection of carrageenan (1 mg) into the rat hind paw caused a time-dependent increase in paw volume that was maximal 3 h after injection. At this time, the concentration of nerve growth factor (NGF) in the skin of the inflamed paw was more than twofold higher than in the contralateral, non-inflamed paw. Treatment of rats with indomethacin reduced inflammatory oedema by 57%, morphine treatment attenuated oedema by 62%. While indomethacin had no statistically significant effect on the concentration of NGF in the skin of inflamed paws, morphine attenuated the NGF response by 24.2% in a naloxone reversible manner. These data suggest that drug-induced inhibition of inflammatory oedema is not predictive of its effect on an inflammation-induced rise in tissue NGF. Furthermore, our results confirm and extend previous observations suggesting an anti-inflammatory activity of morphine.     

胶质瘤中间质细胞衍生因子-1及神经生长因子的表达及临床意义

目的 探讨间质细胞衍生因子-1(SDF-1)及神经生长因子(NGF)在胶质瘤中的表达及临床意义.方法 收集手术切除的人脑胶质瘤病理标本86例为观察组,其中观察组按不同病理级别分为Ⅰ级15例为Ⅰ组,Ⅱ级24例为Ⅱ组,Ⅲ级26例为Ⅲ组,Ⅳ级21例为Ⅳ组,同期随机选择颅脑外伤患者正常脑组织标本84例为对照组,2组组织均使用实时荧光定量聚合酶链式反应(RT-PCR)技术检测SDF-1与NGF mRNA,同时采用免疫组化法检测2组组织中SDF-1与NGF蛋白的表达情况.比较2组组织中SDF-1与NGF mRNA及蛋白表达情况.结果 观察组SDF-1与NGF mRNA基因表达量及蛋白阳性率均高于对照组(P<0.05);Ⅳ组SDF-1与NGF mRNA基因表达量及蛋白阳性率均高于Ⅲ组;Ⅲ组SDF-1与NGF mRNA基因表达量及蛋白阳性率均高于Ⅱ组;Ⅱ组SDF-1与NGF mRNA基因表达量及蛋白阳性率均高于Ⅰ组,胶质瘤组织中SDF-1与NGF mRNA基因表达量及蛋白阳性率随病理级别的增高而增高(P<0.05);胶质瘤组织中SDF-1 mRNA表达量及蛋白阳性率呈正相关(r=0.95,P<0.05),NGF mRNA表达量及蛋白阳性率呈正相关(r=0.96,P<0.05);SDF-1和NGF高表达均是预测胶质瘤预后不良的独立因素(P<0.01),SDF-1和NGF的高表达与胶质瘤患者整体不良预后显著相关.结论 胶质瘤中SDF-1与NGF高表达对病变进展有一定促进作用,二者与肿瘤的病理级别密切相关,两者相互作用,SDF-1与NGF在胶质瘤的发生发展中扮演重要的角色,有望为胶质瘤的临床检测及治疗提供新思路.     

Shape changes induced by biologically active peptides and nerve growth factor in blood platelets of rabbits.

1 Nerve growth factor (NGF), substance P (SP) and thymopoietin all caused shape change reactions of rapid onset in rabbit platelets. NGF had the highest maximal effect, and SP the lowest EC50 (concentration causing half maximal shape change). The action of SP was reversible within 5 min, whereas that of NGF lasted for at least 1 h. A series of other peptides were inactive. 2 After preincubation of platelets with SP, a second application of SP no longer caused a shape change reaction, whereas the effect of NGF was not influenced. 3 An oxidized NGF-derivative without biological activity did not cause a shape change reaction, neither did epidermal growth factor. 4 Prostaglandin E1 (PGE1) and pretreatment of the platelets with 3% butanol, which counteract the shape changes caused by 5-hydroxytryptamine (5-HT) and adenosine 3',5'-diphosphate, also antagonized those induced by NGF and SP. Neither heparin nor methysergide, an antagonist of 5-HT-receptors, influenced the shape change induced by NGF or SP. The action of NGF was also antagonized by a specific antibody to NGF. 5 Thymopoietin, like the basic polypeptide polyornithine (mol. wt. 40,000) was not antagonized by PGE1 and butanol. Heparin, which counteracted the effect of polyornithine, did not influence that of thymopoietin. 6 In conclusion, different modes of action are involved in the shape change of blood platelets induced by polypeptides and proteins. SP and NGF may act by stimulating specific membrane receptors.