TRP通道在内脏痛中的研究进展

瞬时受体电位离子通道(transient receptor potential ion channel,TRP)在内脏痛疾病模型研究中的广泛报道与其配体在临床上有限范围的应用形成鲜明对比。TRPV1就是这种不平衡最典型的例子,它是目前临床上针对膀胱感觉功能障碍治疗的重要TRP蛋白靶标。我们至今仍不清楚为什么存在这种差异,也可能是由于TRP作为外界机械刺激和化学刺激的感受器和传感器的多功能性造成的。这篇综述阐述了内脏感受的不同感觉通路,以及这些通路中表达TRP通道的伤害性感受和非伤害性感受神经元。TRP通道不仅可作为内脏感觉传入中机械和化学刺激的感受器,还在激活GPCR和细胞因子受体后形成一种细胞活化的效应机制。在病理状态下TRP通道的作用可能会发生明显改变,如慢性痛或炎症反应。TRP通道在疼痛的进一步发展、治疗和干预措施中已展现出明显的潜力,而且逐渐显示出炎症反应的发生也有可能受益于此。因此,尽管已进行了大量的基础研究,但我们对TRP通道参与内脏感受通路的潜在机制的探索仍然处于开始阶段。     

炎症介质及瞬时受体电位通道对神经性疼痛的研究进展

神经性疼痛是由中枢敏化和外周敏化综合作用导致的慢性疼痛,较多疾病均可以引起神经性疼痛,如带状疱疹后神经痛、偏头痛、腰椎间盘突出症等,其中炎症介质、神经肽、通道蛋白等发挥了重要的作用。基于此,本文从6种主要的炎症介质和3种瞬时受体电位(TRP)离子通道论述其对神经性疼痛的影响,为神经性疼痛的机制及治疗靶点研究提供参考。     

瞬时受体电位家族在肠易激综合征中的作用机制研究进展

瞬时受体电位(transient receptor potential, TRP)家族是一类位于细胞膜和胞内细胞器膜的阳离子配体门控通道蛋白。TRP通道广泛分布于哺乳动物的神经元和非神经细胞,在温度、pH值、机械力等多种物理因素和各种内、外源性的化学介质刺激下,参与躯体和内脏伤害性信号的感觉及传导,对肠易激综合征(irritable bowel syndrome, IBS)患者内脏高敏感性的产生有重要的作用。IBS患者结直肠中TRP通道的表达水平和功能发生明显改变,以TRP通道作为治疗IBS新的药物靶点在研究中取得了初步的成效,为治疗IBS提供了新的依据。     

血清淀粉样蛋白A与肾脏相关疾病的研究进展

血清淀粉样蛋白A(Serum amyloid A Protein,SAA)是主要的急性时相反应蛋白,能非常敏感的反应炎症[1]。而在肾移植排斥反应和2型糖尿病肾病等肾脏相关疾病的发病过程中均有炎症反应的存在,SAA作为机体主要的急性时相反应蛋白在这些疾病的诊疗中发挥特殊作用。现就在肾脏相     

脑梗死患者血清IDO及KAT比活性测定

目的 探讨吲哚氨2,3-双加氧酶(IDO)及犬尿氨酸氨基转移酶(KAT)活性在脑梗死患者中的变化情况及病理作用.方法 正常对照组35例和脑梗死组81例,采用免疫透射比浊法测定血清超敏C反应蛋白(hsCRP)、载脂蛋白A1(APOA1)、载脂蛋白B(APOB)浓度,采用酶法分析甘油三酯(TG)、总胆固醇(CHO)、高密度脂蛋白(HDL)、低密度脂蛋白(LDL)、游离脂肪酸(NEFA)浓度,采用HPLC-荧光衍生法测定血液色氨酸(TRP)、犬尿氨酸(KYN)及犬尿喹啉酸(KYNA)浓度,计算IDO及KAT比活性,并进行对照分析.结果 脑梗死组TRP、KYNA、HDL、KAT比活性明显低于对照组(P均＜0.05).脑梗死组hsCRP、IDO比活性明显高于对照组(P均＜0.01).脑梗死患者IDO比活性与hsCRP呈正相关(r=0.425,P=0.027).结论 脑梗死患者体内存在炎症反应,炎症应答上调IDO的活性表达,进而影响KYN代谢途径,可能与脑梗死患者的病理生理密切相关.     

内源性气体信号分子硫化氢与炎症反应

硫化氢(H2S)是继NO、CO后的第三种气体信使,在哺乳动物中发挥了重要的生理和病理作用.H2S可刺激ATP敏感性钾通道(ATP-sensitive potassium channels,KATP)产生一系列生理效应,是人炎症反应中的介质.体内试验的结果表明,H2S可能既有促炎症效应也同时具有抗炎症效应.研究显示,H2S不仅在全身炎症反应中过量产生,更多的是在局部炎症中产生.在脓毒性/内毒素性休克、失血性休克大鼠动物模型中,都有H2S的合成增加.H2S本身也可诱导神经源性炎症.在这些疾病状态下,减少H2S的生成具有治疗作用.     

胰岛素泵治疗对不同病程2型糖尿病患者8-异前列腺素F2α的影响

8-异前列腺素F2α是细胞膜上脂化的花生四烯酸受自由基攻击后裂解而形成的前列腺素衍生物,其产生与机体氧化应激损伤关系极为密切,是评价氧化应激和脂质过氧化反应最有效的生物指标之一[1].其可以促进胰岛素抵抗及胰岛β细胞功能凋亡.2型糖尿病被证实与氧化应激及炎症密切相关,C-反应蛋白是反应炎症的重要因子.胰岛素泵强化治疗可在短期内获得理想的血糖控制,逆转高血糖的某些毒性作用,使胰岛β细胞功能得到恢复,胰岛素分泌增加,改善机体胰岛素抵抗[2].目前国内外对胰岛素泵干预对8-异前列腺素F2α及C反应蛋白的影响尚未见相关报道,本试验通过对不同病程的2型糖尿病患者胰岛素泵强化治疗,测定8-异前列腺素F2α及C反应蛋白的变化情况,探讨胰岛素泵在氧化应激及炎症中的作用.     

高血压左心室肥厚患者QT离散度与高敏C反应蛋白的关系

QT离散度(QTd)是近年来提出的预测心血管事件及心源性猝死的新指标.国内外有研究证实QTd与左心室肥厚(LVH)有关,并随左心室质量增加而增大,'[1-2]>.最近有研究认为炎症标志物高敏C反应蛋白(hsCRP)是高血压患者合并LVH的独立预测指标,而国内外对此研究尚少[3].本研究旨在探讨炎症在高血压LVH患者左心室重构中的作用及与QT离散度的关系.     

TRPM8的研究进展

瞬时受体电位通道(transient receptor potential,TRP)是位于细胞膜上的一类重要的阳离子通道超家族。TRP通道分布广泛,调节机制各异,通过感受细胞内外环境的各种刺激,参与痛觉、机械感觉、味觉的发生和维持细胞内外环境的离子稳态等众多生命活动,具有调节肌肉收缩、递质释放、细胞增殖、细胞分化、基因转录、细胞凋亡及细胞死亡等作用。TRP通道亚型TRPM8是一种非选择性阳离子通道,最初作为一种前列腺特异性蛋白被克隆出来,现发现在结肠癌、肺癌、乳腺癌以及皮肤来源的恶性肿瘤中均有表达。TRPM8可以被冷刺激和薄荷醇激活,TRPM8参与温度觉和疼痛觉调控,并可调节血管收缩和扩张,尤其是TRPM8在调节细胞生长和死亡方面具有重要的作用,为我们研究肿瘤的发生发展提供了重要的研究线索。     

C反应蛋白及其单个核苷酸多态性与冠心病的相关性

冠心病(CAD)发病是遗传因素和环境因素共同作用的结果.冠状动脉粥样硬化是一种慢性炎症反应,是CAD病理过程的基础,炎症反应贯穿了冠状动脉粥样硬化的整个过程.血清C反应蛋白(CRP)是炎症反应的标志物,不仅可预测CAD发病和发生的风险[1-2],还可对CAD预后进行评估[3-5].     

TRP channel and cardiovascular disease

The transient receptor potential (TRP) channel superfamily consists of 28 mammalian cation channels and is expressed in almost every tissue, including the heart and vasculature; most TRP channels are permeable to Ca(2+) and are prime molecular candidates for store-operated channels (SOCs), receptor-operated channels (ROCs), ligand-gated channels (LGCs) and stretch-activated channels (SACs). As these channels act as multifunctional cellular sensors and are involved in several fundamental cell functions such as contraction, proliferation and cell death, investigation of their roles in human disease is very important. This review presents an overview of current knowledge about the pathological role of TRP channels in cardiovascular diseases and highlights some TRP channels for which a role in the diseases can be anticipated. Evidences suggest that up-regulation of TRPC channels is involved in the development of cardiac hypertrophy and heart failure; TRPM4 participates in some features of cardiac arrhythmias; increased expression of TRPC channels is associated with vascular remodeling and pulmonary hypertension; reduced expression or activity of TRPV4 impairs endothelium-dependent vasorelaxation; TRPC3/C4 and TRPM2 act as endothelial redox sensors; and TRPC1, -C4, -C6, -V4, and -M2, have been implicated in endothelial barrier dysfunction. Ultimately, TRP channels will become important novel pharmacological targets for the treatment of human cardiovascular diseases.     

Transient receptor potential (TRP) channels as drug targets for diseases of the digestive system

Approximately 20 of the 30 mammalian transient receptor potential (TRP) channel subunits are expressed by specific neurons and cells within the alimentary canal. They subserve important roles in taste, chemesthesis, mechanosensation, pain and hyperalgesia and contribute to the regulation of gastrointestinal motility, absorptive and secretory processes, blood flow, and mucosal homeostasis. In a cellular perspective, TRP channels operate either as primary detectors of chemical and physical stimuli, as secondary transducers of ionotropic or metabotropic receptors, or as ion transport channels. The polymodal sensory function of TRPA1, TRPM5, TRPM8, TRPP2, TRPV1, TRPV3 and TRPV4 enables the digestive system to survey its physical and chemical environment, which is relevant to all processes of digestion. TRPV5 and TRPV6 as well as TRPM6 and TRPM7 contribute to the absorption of Ca²⁺ and Mg²⁺, respectively. TRPM7 participates in intestinal pacemaker activity, and TRPC4 transduces muscarinic acetylcholine receptor activation to smooth muscle contraction. Changes in TRP channel expression or function are associated with a variety of diseases/disorders of the digestive system, notably gastro-esophageal reflux disease, inflammatory bowel disease, pain and hyperalgesia in heartburn, functional dyspepsia and irritable bowel syndrome, cholera, hypomagnesemia with secondary hypocalcemia, infantile hypertrophic pyloric stenosis, esophageal, gastrointestinal and pancreatic cancer, and polycystic liver disease. These implications identify TRP channels as promising drug targets for the management of a number of gastrointestinal pathologies. As a result, major efforts are put into the development of selective TRP channel agonists and antagonists and the assessment of their therapeutic potential.     

Human odontoblasts express functional thermo-sensitive TRP channels: implications for dentin sensitivity

Odontoblasts form the outermost cellular layer of the dental pulp where they have been proposed to act as sensory receptor cells. Despite this suggestion, evidence supporting their direct role in mediating thermo-sensation and nociception is lacking. Transient receptor potential (TRP) ion channels directly mediate nociceptive functions, but their functional expression in human odontoblasts has yet to be elucidated. In the present study, we have examined the molecular and functional expression of thermo-sensitive TRP channels in cultured odontoblast-like cells and in native human odontoblasts obtained from healthy wisdom teeth. PCR and western blotting confirmed gene and protein expression of TRPV1, TRPA1 and TRPM8 channels. Immunohistochemistry revealed that these channels were localised to odontoblast-like cells as determined by double staining with dentin sialoprotein (DSP) antibody. In functional assays, agonists of TRPV1, TRPA1 and TRPM8 channels elicited [Ca²⁺]_i transients that could be blocked by relevant antagonists. Application of hot and cold stimuli to the cells also evoked rises in [Ca²⁺]_i which could be blocked by TRP-channel antagonists. Using a gene silencing approached we further confirmed a role for TRPA1 in mediating noxious cold responses in odontoblasts. We conclude that human odontoblasts express functional TRP channels that may play a crucial role in mediating thermal sensation in teeth.     

Adenovirus-transduced dendritic cells stimulate cellular immunity to melanoma via a CD4(+) T cell-dependent mechanism

We previously showed that genetic immunization of C57BL/6 mice with recombinant adenovirus encoding human TRP2 (Ad-hTRP2) was able to circumvent tolerance and induce cellular and humoral immune responses to murine TRP2 associated with protection against metastatic growth of B16 melanoma. In the present study we compared delivery of Ad-hTRP2 with cultured dendritic cells (DC) and direct injections of Ad-hTRP2. We show that application of Ad-hTRP2 with cultured DC enhanced protective immunity to B16 melanoma cells. Most importantly, delivery of recombinant adenovirus with DC alters the character of the immune response resulting in preferential stimulation of strong cellular immunity in the absence of significant humoral immunity to the encoded antigen. Adoptive transfer of lymphocytes from mice immunized with Ad-hTRP2-transduced DC confirmed that cellular components of the immune response were responsible for rejection of B16 melanoma. The protective efficacy of Ad-hTRP2-transduced DC clearly depended on the presence of CD4(+) T helper cells. Furthermore, AD-hTRP2-transduced DC, but not direct injection of Ad-hTRP2, were effective in the presence of neutralizing anti-adenoviral antibodies. These preclinical studies demonstrate the superiority of melanoma vaccines consisting of cultured DC transduced with recombinant adenoviruses encoding melanoma antigens.     

Transient receptor potential 1 regulates capacitative Ca(2+) entry and Ca(2+) release from endoplasmic reticulum in B lymphocytes

Capacitative Ca(2+) entry (CCE) activated by release/depletion of Ca(2+) from internal stores represents a major Ca(2+) influx mechanism in lymphocytes and other nonexcitable cells. Despite the importance of CCE in antigen-mediated lymphocyte activation, molecular components constituting this mechanism remain elusive. Here we demonstrate that genetic disruption of transient receptor potential (TRP)1 significantly attenuates both Ca(2+) release-activated Ca(2+) currents and inositol 1,4,5-trisphosphate (IP(3))-mediated Ca(2+) release from endoplasmic reticulum (ER) in DT40 B cells. As a consequence, B cell antigen receptor-mediated Ca(2+) oscillations and NF-AT activation are reduced in TRP1-deficient cells. Thus, our results suggest that CCE channels, whose formation involves TRP1 as an important component, modulate IP(3) receptor function, thereby enhancing functional coupling between the ER and plasma membrane in transduction of intracellular Ca(2+) signaling in B lymphocytes.     

Postprandial apolipoprotein B100 and B48 metabolism in familial combined hyperlipidaemia before and after reduction of fasting plasma triglycerides*

Abstract Hepatic VLDL overproduction in familial combined hyperlipidaemia (FCH) may delay the clearance of atherogenic apolipoprotein (apo) B containing particles. We investigated if normalization of fasting plasma triglycerides (TG) by hypolipidaemic treatment results in improved metabolism of apo B48 and apo B100 in six male subjects with FCH and compared them to six normolipidaemic controls. The FCH patients were studied before (TG, 5·2±1·2 mmoll^-1; mean ± SEM) and after therapy (TG, 2·1±0·3 mmoll^-1) with either simvastatin (n= 4) or combined therapy with gemfibrozil (n= 2). The post-prandial changes of apo B100 and apo B48 were studied after a single oral fat meal (24h; 50 gram fatm^-2). Changes in triglyceride rich particles (TRP; d < 1·006 gml^-1) and remnant fractions (REM; d: 1·006–1·019g ml^-1) of apo B were quantitated by scanning silverstained SDS-PAGE (4–15%). Apo B48 in fasting TRP in untreated and treated FCH was 15% and 14% of total apo B, and 6% in controls (P < 0·05). In controls, postprandial B48 increased maximally at 4h by 81% in TRP and by 137% in REM compared to baseline. In treated FCH, the post-prandial apo B48 pattern normalized in TRP compared to the untreated state. Postprandial apo B100 in controls decreased in TRP and REM by 33% and 18% (P < 0·05). In untreated and treated FCH, postprandial apo B100 remained unchanged vs. baseline in TRP and in REM suggesting hypersecretion of VLDL. The elimination of B100—assessed as area under the curve—in TRP (32·5±3·6 au.h; mean±SEM) and REM fractions (33·2±3·1 au.h), improved significantly after treatment (21·0±2·8 and 20·4±3·3 au.h, respectively). The apo B48 clearance in TRP fractions was improved after treatment (4·3±1·4 au.h vs. 2·9±1·2 au.h; P= 0·06), but not in REM fractions (2·8±1·0 au.h vs. 1·8±0·5 au.h; NS). In conclusion, in FCH subjects with apo B100 hypersecretion and increased fasting plasma apo B48 levels, reduction of fasting plasma TG improved, but did not normalize, TRP apo B48 and B100 metabolism. However, therapy normalized postprandial apo B100 remnant metabolism. Impaired postprandial apo B metabolism may be instrumental in the development of premature atherosclerosis in FCH subjects.     

Cation channels of the transient receptor potential superfamily: their role in physiological and pathophysiological processes of smooth muscle cells

Smooth muscle cells (SMC) are essential components of many tissues of the body. Ion channels regulate their membrane potential, the intracellular Ca(2+) concentration ([Ca(2+)](i)) and their contractility. Among the ion channels expressed in SMC cation channels of the transient receptor potential (TRP) superfamily allow the entry of Na(+), Ca(2+) and Mg(2+). Members of the TRP superfamily are essential constituents of tonically active channels (TAC), receptor-operated channels (ROC), store-operated channels (SOC) and stretch-activated channels (SAC). This review focusses on TRP channels (TRPC1, TRPC3, TRPC4, TRPC5, TRPC6, TRPC7, TRPV2, TRPV4, TRPM4, TRPM7, TRPP2) whose physiological functions in SMC were dissected by downregulating channel activity in isolated tissues or by the analysis of gene-deficient mouse models. Their possible functional role and physiological regulation as homomeric or heteromeric channels in SMC are discussed. Moreover, TRP channels may also be responsible for pathophysiological processes involving SMC-like airway hyperresponsiveness and pulmonary hypertension. Therefore, they present important drug targets for future pharmacological interventions.     

Alpha1-adrenergic receptors activate Ca(2+)-permeable cationic channels in prostate cancer epithelial cells

The prostate gland is a rich source of alpha1-adrenergic receptors (alpha1-ARs). alpha1-AR antagonists are commonly used in the treatment of benign prostatic hyperplasia symptoms, due to their action on smooth muscle cells. However, virtually nothing is known about the role of alpha1-ARs in epithelial cells. Here, by using two human prostate cancer epithelial (hPCE) cell models - primary cells from resection specimens (primary hPCE cells) and an LNCaP (lymph node carcinoma of the prostate) cell line - we identify an alpha1A subtype of adrenergic receptor (alpha1A-AR) and show its functional coupling to plasmalemmal cationic channels via direct diacylglycerol (DAG) gating. In both cell types, agonist-mediated stimulation of alpha1A-ARs and DAG analogues activated similar cationic membrane currents and Ca(2+) influx. These currents were sensitive to the alpha1A-AR antagonists, prazosin and WB4101, and to transient receptor potential (TRP) channel blockers, 2-aminophenyl borate and SK&F 96365. Chronic activation of alpha1A-ARs enhanced LNCaP cell proliferation, which could be antagonized by alpha1A-AR and TRP inhibitors. Collectively, our results suggest that alpha1-ARs play a role in promoting hPCE cell proliferation via TRP channels.     

Cytotoxic T lymphocytes responding to low dose TRP2 antigen are induced against B16 melanoma by liposome-encapsulated TRP2 peptide and CpG DNA adjuvant

The induction of a potent and specific T cell response is a major challenge in the development of efficacious cancer vaccine strategies. We applied a novel liposomal formulation (AVE3) for efficient delivery of antigenic peptides into APCs of the skin. These liposomes resulted in a long-lasting deposition of encapsulated compounds at the injection site and the draining lymph nodes. Using a peptide from the melanocyte differentiation antigen tyrosinase-related protein (TRP2) 2 we could show that vaccination with liposome-encapsulated peptide in combination with oligodeoxynucleotides containing unmethylated CpG motifs (CpG ODNs) as adjuvant leads to the induction of tumor cell-specific cytotoxic T cells. The most potent immune response was observed when both, TRP2 peptide and CpG ODNs, were encapsulated into AVE3. Importantly, in contrast to vaccination with free TRP2 liposomal TRP2 peptide generated T cells which respond to 1000-fold lower antigen concentration. Using the poorly immunogenic B16 melanoma model we could demonstrate that vaccination with liposomal TRP2 peptide plus CpG ODNs but not vaccination with free peptide or adjuvant alone resulted in tumor protection in subcutaneous and metastatic tumor models. In summary, vaccination with liposome-encapsulated peptide antigen and CpG ODN allows for the in vivo loading and activation of DC, thereby generating reactive CTL populations even against poorly immunogenic self-peptide presenting tumors resulting in a potent anti-tumor immune response.     

The TRP proteins, a rapidly expanding Ca2+ entry channel family and a new molecular target for drug development]

There is a rapidly expanding protein family which encompasses a broad repertoire of cation-selective channels serving as a continuous Ca2+ entry pathway into the cell. The transient receptor potential protein (TRP) and its relatives, which were originally thought to be Ca (2+)-permeable cation channels activated upon the stimulation of G-protein coupled and tyrosine kinase receptors, are now becoming promising candidates mediating a variety of cellular responses and functions such as mechano/chemo-transduction, oxidative stress, and cell survival/proliferation. This short paper briefly overviews the current knowledge about these proteins as a new target for drug discovery and development.