磷酸二酯酶4抑制剂对阿尔茨海默病、抑郁症及二者共病的潜在治疗作用及其机制研究进展

磷酸二酯酶4(PDE4)作为PDE家族中数量最多的一类成员,特异性水解细胞内第二信使环磷酸腺苷（cAMP）,并参与多种生理功能的调节,在中枢神经系统疾病的发生发展中发挥重要作用。近年研究表明,PDE4是治疗抑郁症及记忆和认知障碍等神经精神疾患的重要靶点。通过调控PDE4的活性和表达使脑内cAMP表达水平及cAMP介导的信号通路恢复正常,将为阿尔茨海默病、抑郁症及二者共病等神经精神疾病提供重要的治疗策略。本文对PDE4与这些疾病之间关系的最新研究进展进行综述和讨论,为阿尔茨海默病、抑郁症及二者共病的预防和治疗提供新的思路及对策。     

磷酸二酯酶在慢性疼痛与阿尔茨海默病共病中的作用研究进展

慢性疼痛与阿尔茨海默病（AD）是困扰人类的两大疾病。流行病学调查显示,慢性疼痛患者常伴有情感和认知功能异常,而AD患者也常伴有慢性疼痛,这提示慢性疼痛与AD可能存在相似或共同的病理生理机制,但其详细机制尚不明确。磷酸二酯酶（PDE）具有特异性水解细胞内第二信使环磷酸腺苷（cAMP）和（或）环磷酸鸟苷（cGMP）的功能。最新研究报道,PDE家族中PDE2,4,5或7亚型可通过激活cAMP/蛋白激酶A和（或）cGMP/蛋白激酶G,促进其下游信号通路磷酸腺苷反应元件结合蛋白的磷酸化和脑源性神经营养因子的表达,从而不同程度地改善AD小鼠的认知功能障碍,缓解慢性疼痛小鼠的痛觉异常。本文综述PDE在慢性疼痛和AD共病中的作用及相关机制。     

磷酸二酯酶4抑制剂治疗银屑病的研究进展

银屑病是一种遗传和环境共同作用诱发的、免疫介导的慢性炎症性皮肤病.环磷酸腺苷(cAMP)/蛋白激酶A(PKA)通路与银屑病的发病机制密切相关,而磷酸二酯酶4是可以专一水解cAMP的酶,因此磷酸二酯酶4成为银屑病治疗的期望小分子靶点.磷酸二酯酶4抑制剂类药物通过竞争性阻断磷酸二酯酶4对cAMP的降解作用,使T辅助细胞1(...     

磷酸二酯酶参与认知与情绪调节的研究进展

磷酸二酯酶(PDE)催化水解cAMP和cGMP,是细胞内降解cAMP和cGMP的唯一途径。PDE是一个多基因大家族酶,包含11型不同家族,它们的结构,分布以及调节方式对抑制剂的敏感性都不同。PDE选择性抑制剂可通过抑制cAMP或cGMP水解来调节学习记忆障碍等中枢神经系统疾病。因此,PDE被认为在中枢神经系统疾病的治疗上具有重要地位。本综述介绍目前PDE参与学习记忆障碍这一中枢神经系统疾病调节的研究进展,而且PDE作为中枢神经系统疾病的治疗靶点,研究其选择性抑制剂具有重要的意义。     

磷酸二酯酶4抑制剂临床及安全性研究进展

磷酸二酯酶4 (phosphodiesterase 4, PDE4)是磷酸二酯酶家族中重要成员之一,可特异性水解环磷酸腺苷(cyclic adenosine monophosphate, cAMP),通过改变cAMP浓度引发下游磷酸化级联反应,与多种疾病密切相关。靶向PDE4的抑制剂临床研究包括呼吸系统疾病、自身免疫性疾病、中枢神经系统疾病及皮肤病等多种疾病领域。但是在已上市的PDE4抑制剂临床研究中发现,大多数药物的恶心、呕吐等胃肠道不良反应发生率较高,限制了其临床应用。因此本综述总结了已上市PDE4抑制剂的临床进展及安全性问题,结合PDE4蛋白结构分析、PDE4抑制剂的作用机制及相关不良反应机制研究,阐述了PDE4抑制剂产生不良反应的主要原因,旨在为开发安全有效的PDE4抑制剂提供参考。     

茶碱、咯利普兰和acetamide—45对GL62酵母细胞表达的人磷酸二酯酶4A的抑制作用

目的:研究GL62 酵母细胞中磷酸二酯酶4A(PDE4A)的诱导表达和茶碱、咯利普兰、N-对氟苄基-3-[(N-4-吡啶)-乙酰胺]-吲哚45(acetamide-45)对GL62酵母细胞诱导提取物中PDE4A活性的抑制作用.方法:克隆了人PDE4A基因的GL62酵母细胞在CuSO_4 150μmol/L条件下诱导表达PDE4A并提取,用高效液相色谱法测定PDE4A的活性.结果:GL62酵母细胞在CuSO_4诱导下的表达产物蛋白分子在62 kDa和83 kDa之间,表达产物的PDE4A的活性在3 h达到最大为(188±23)μmol·g~(-1)·min~(-1),其米氏常数 K_m为(17.7±2.6)μmol·L~(-1).茶碱,咯利普兰和acetamide-45对诱导提取物PDE4A活性的IC_(50)(95 ％可信限)分别为1642(989-2727),4.58(3.45-6.08)和275(170-444)μmol·L~(-1).结论:GL62酵母细胞经CuSO_4诱导可表达PDE4A,茶碱、咯利普兰和 acetamide-45能抑制其活性,GL62酵母细胞的诱导表达提取物可用来研究PDE4A及其抑制剂.     

磷酸二酯酶及其抑制剂的研究进展

磷酸二酯酶(PDEs)是一类可水解细胞内第二信使环磷酸腺苷(cyclic adenosine monophosphate,cAMP)和环磷酸鸟苷(cyclic guanosine monophosphate,cGMP)的酶类,可调节细胞内的多种信号传递和生理活动。PDEs由11种不同的家族组成,且各家族包含不同的亚型,各个亚型在细胞内分布、表达、调节方式以及对抑制剂的敏感性均不同,参与了炎症、哮喘、抑郁、勃起功能障碍等多种病理过程的发生发展,这些特点使得PDE作为新的药物靶点得到了越来越多的关注。该文将从PDE各家族生物学特点、生理病理学意义及其抑制剂的应用作一简单综述。     

磷酸二酯酶2对抑郁焦虑及认知障碍等中枢神经疾病的调节作用

磷酸二酯酶（Phosphodiesterase,PDE）水解细胞内第二信使-环磷酸腺苷和环磷酸鸟苷,降低细胞内第二信使的含量,进而影响下游信号转导,调节细胞内的生命活动。磷酸二酯酶2（PDE2）是磷酸二酯酶大家族的成员之一,在中枢神经系统中分布广泛,尤其在海马和杏仁核部分密集,近年来越来越多的研究表明PDE2可能参与中枢神经系统疾病的调节,而相应的PDE2抑制剂可能具有治疗抑郁、焦虑和学习记忆障碍等中枢神经系统疾病前景。本文综述了PDE2在中枢神经系统疾病调节中的作用及其抑制剂在治疗相关疾病的应用。     

磷酸二酯酶5抑制剂改善阿尔茨海默病认知功能的研究进展

近年研究发现磷酸二酯酶5(Phosphodiesterase-5,PDE5)在阿尔茨海默病(Alzheimer’s disease,AD)发生发展过程的作用倍受关注,其抑制剂可明显增强动物和人的认知功能,其机制与干预AD发病过程如改善血管功能紊乱、促进神经递质释放、促进神经再生及抗凋亡等作用有关。因此,PDE5抑制剂可能为AD的治疗提供新方向。本文中,笔者结合国内外相关研究进展,重点阐述PDE5抑制剂对AD的保护作用及其相关作用机制。     

PDE4 as a target for cognition enhancement

Introduction: The second messengers cAMP and cGMP mediate fundamental aspects of brain function relevant to memory, learning, and cognitive functions. Consequently, cyclic nucleotide phosphodiesterases (PDEs), the enzymes that inactivate the cyclic nucleotides, are promising targets for the development of cognition-enhancing drugs.

Areas covered: PDE4 is the largest of the 11 mammalian PDE families. This review covers the properties and functions of the PDE4 family, highlighting procognitive and memory-enhancing effects associated with their inactivation.

Expert opinion: PAN-selective PDE4 inhibitors exert a number of memory- and cognition-enhancing effects and have neuroprotective and neuroregenerative properties in preclinical models. The major hurdle for their clinical application is to target inhibitors to specific PDE4 isoforms relevant to particular cognitive disorders to realize the therapeutic potential while avoiding side effects, in particular emesis and nausea. The PDE4 family comprises four genes, PDE4A-D, each expressed as multiple variants. Progress to date stems from characterization of rodent models with selective ablation of individual PDE4 subtypes, revealing that individual subtypes exert unique and non-redundant functions in the brain. Thus, targeting specific PDE4 subtypes, as well as splicing variants or conformational states, represents a promising strategy to separate the therapeutic benefits from the side effects of PAN-PDE4 inhibitors.     

磷酸二酯酶9及其抑制剂的研究进展

目的为磷酸二酯酶9(phosphodiesterase 9,PDE 9)的研究与开发提供参考。方法查阅PDE 9及其抑制剂的研究开发现状的多篇相关文献,进行整理和归纳。结果大多数PDE9抑制剂都能选择性地在体外和体内抑制PDE 9,并取得较好的药理活性。结论PDE 9将成为药物治疗的新一代靶点,其抑制剂的研究与开发具有广阔的发展前景。     

Benzofuran and quinoline carboxamides and quinoline sulfonamides as TNF inhibitors and as PDE4 inhibitors

In these three patent applications, Chiroscience describes inhibitors of phosphodiesterase Type 4 (PDE4), an enzyme responsible for degrading levels of cAMP in cells. Increased levels of cellular cAMP limit the production of the proinflammatory cytokine TNFα. Therefore, agents that block the effects of PDE4 would maintain elevated cAMP levels and the synthesis of TNFα would be attenuated. This effect could have a beneficial impact on the treatment of inflammatory diseases such as arthritis and asthma. The compounds that are claimed have sought to replace the dialkoxyphenyl ring of rolipram-based inhibitors with other heterocycles in an effort to discover the optimum pharmacophore and lead to improved properties for this class of compounds.     

GEBR-7b, a novel PDE4D selective inhibitor that improves memory in rodents at non-emetic doses

BACKGROUND AND PURPOSE

Strategies designed to enhance cerebral cAMP have been proposed as symptomatic treatments to counteract cognitive deficits. However, pharmacological therapies aimed at reducing PDE4, the main class of cAMP catabolizing enzymes in the brain, produce severe emetic side effects. We have recently synthesized a 3-cyclopentyloxy-4-methoxybenzaldehyde derivative, structurally related to rolipram, and endowed with selective PDE4D inhibitory activity. The aim of the present study was to investigate the effect of the new drug, namely GEBR-7b, on memory performance, nausea, hippocampal cAMP and amyloid-β (Aβ) levels.

EXPERIMENTAL APPROACH

To measure memory performance, we performed object recognition tests on rats and mice treated with GEBR-7b or rolipram. The emetic potential of the drug, again compared with rolipram, was evaluated in rats using the taste reactivity test and in mice using the xylazine/ketamine anaesthesia test. Extracellular hippocampal cAMP was evaluated by intracerebral microdialysis in freely moving rats. Levels of soluble Aβ peptides were measured in hippocampal tissues and cultured N2a cells by elisa.

KEY RESULTS

GEBR-7b increased hippocampal cAMP, did not influence Aβ levels and improved spatial, as well as object memory performance in the object recognition tests. The effect of GEBR-7b on memory was 3 to 10 times more potent than that of rolipram, and its effective doses had no effect on surrogate measures of emesis in rodents.

CONCLUSION AND IMPLICATIONS

Our results demonstrate that GEBR-7b enhances memory functions at doses that do not cause emesis-like behaviour in rodents, thus offering a promising pharmacological perspective for the treatment of memory impairment.     

Inhibition of eotaxin-mediated human eosinophil activation and migration by the selective cyclic nucleotide phosphodiesterase type 4 inhibitor rolipram

1. The effect of the selective type 4 phosphodiesterase (PDE 4) inhibitor rolipram on human eosinophil activation and migration mediated by eotaxin was investigated.
2. Studies were performed with human freshly isolated eosinophils from peripheral blood of healthy donors by a magnetic cell separation (MACS) technique to a purity>99%. To test the effect of rolipram, eosinophils were stimulated with recombinant human eotaxin and the cell surface activation markers CD11b and L-selectin were analysed by flow cytometry. Furthermore, eotaxin mediated eosinophil migration was measured in a transendothelial chemotaxis assay.
3. Our results indicate that rolipram inhibited eotaxin-induced CD11b up-regulation up to 60.6±7.6% at the highest tested dose (10 μM), whereas transendothelial chemotaxis was partially inhibited reaching a plateau of approx. 30% at a rolipram concentration of 0.1 μM.
4. We conclude that the selective PDE 4 inhibitor rolipram decreases eotaxin mediated eosinophil activation, an observation that may contribute to elucidate the mechanism by which PDE 4 inhibitors reduce antigen-induced eosinophil infiltration in different animal models of allergic inflammation.

     

Type 4 cAMP phosphodiesterase (PDE4) inhibitors augment glucocorticoid-mediated apoptosis in B cell chronic lymphocytic leukemia (B-CLL) in the absence of exogenous adenylyl cyclase stimulation

cAMP-mediated signaling potentiates glucocorticoid-mediated apoptosis in lymphoid cells, but an effective means by which to take advantage of this observation in the treatment of lymphoid malignancies has not been identified. The primary objective of the current study was to determine whether PDE4 inhibitors, a class of compounds in late clinical development that raise intracellular cAMP levels by inhibiting type 4 cyclic nucleotide phosphodiesterases (PDE4), increase the efficacy of glucocorticoid-mediated apoptosis in leukemic cells from patients with B cell chronic lymphocytic leukemia (B-CLL). Rolipram, a prototypic PDE4 inhibitor, synergized with glucocorticoids in inducing B-CLL but not T cell apoptosis. Rolipram also augmented glucocorticoid receptor element (GRE) transactivation in B-CLL cells. In contrast, inhibition of protein kinase A (PKA) with the cAMP antagonist Rp-8Br-cAMPS reversed both glucocorticoid-induced apoptosis and GRE transactivation. CCRF-CEM cells, a well-studied model of glucocorticoid and cAMP-induced apoptosis, differed from B-CLL cells in that stimulation of adenylyl cyclase with the diterpene forskolin was required to increase both glucocorticoid-mediated apoptosis and GRE activation, while PDE4 inhibition had no effect. Consistent with these results, inhibition of PDE4 induced cAMP elevation in B-CLL but not CCRF-CEM cells, while forskolin augmented cAMP levels in CCRF-CEM but not B-CLL cells. While rolipram treatment up-regulated PDE4B in B-CLL, forskolin treatment up-regulated PDE4D in CCRF-CEM cells. These studies suggest that PKA is required for and enhances glucocorticoid-induced apoptosis in B-CLL by modulating glucocorticoid receptor signal transduction. Clinical trials that examine whether PDE4 inhibitors enhance the efficacy of glucocorticoid-containing chemotherapy regimens in B-CLL are indicated.     

cAMP-specific phosphodiesterase inhibitors: promising drugs for inflammatory and neurological diseases

Introduction: PDEs are key enzymes in the adenosine and guanosine cyclic nucleotides (cAMP and cGMP) signaling cascade. Their inhibition increases cyclic nucleotide levels inside the cell. Thus, pharmacological modulation of PDE activity can have profound effects on the function of cells and organ systems throughout the body.

Areas covered: Among the large PDE families, only PDE4, PDE7 and PDE8 are cAMP-specific hydrolyzing enzymes. cAMP is an important second messenger not only by its involvement in a vast number of physiological processes but also by activation of protein kinase A, exchange protein activated by cAMP (Epac) and cAMP response element-binding (CREB) or cyclic nucleotide-gated channels. Clearly, such enzymes represent ideal drug targets for the pharmacological treatment of many pathologies. The discovery and development of small molecules targeting cAMP-specific PDEs reported in the last 5 years is the focus of the present review.

Expert opinion: The first PDE4 inhibitors recently reached the market, having avoided, by different strategies, their dose-limiting side effects (after more than two decades of drug development). Meanwhile, new cAMP-specific PDE7 and PDE8 inhibitors emerged as effective and safe drugs for severe unmet diseases. The therapeutic potential of these inhibitors will be tested in the near future, as many of these drug candidates are ready to start clinical trials.     

新型磷酸二酯酶4抑制剂氯比普兰改善老年小鼠的认知功能障碍

目的探讨新型磷酸二酯酶4抑制剂氯比普兰(chlorbipram)对老年小鼠学习记忆功能障碍的影响。方法 20月龄和6月龄昆明雄性小鼠,分别随机分为溶剂对照组和氯比普兰给药组(0.5 mg·kg-1),连续给药21 d。旷场实验检测穿越格子数、直立次数和粪便粒数;新物体识别实验(NOR)检测识别指数(RI);水迷宫实验检测逃避潜伏期、穿越平台时间、目标象限停留时间及路程和游泳速度。ELISA法测定海马环磷酸腺苷(c AMP)的含量,Western蛋白印迹法检测磷酸化蛋白激酶A(p-PKA)和磷酸化c AMP反应元件结合蛋白(p-CREB)的水平;逆转录PCR(RT-PCR)检测脑源性神经营养因子(BDNF)mRNA的表达。结果旷场实验结果显示,20月龄正常组小鼠粪便粒数明显多于6月龄正常组小鼠(P<0.05),给予氯比普兰后粪便粒数明显减少。NOR实验结果表明,20月龄正常组小鼠RI明显低于6月龄正常组小鼠(P<0.01),给予氯比普兰后RI明显升高(P<0.05),达到6月龄正常组小鼠水平。水迷宫实验结果显示,与6月龄正常组小鼠相比,20月龄正常组小鼠穿越平台次数明显减少(P<0.01),第一次到达平台时间明显延长(P<0.05),目标象限的探索时间和路程显著性下降(P<0.01);给予氯比普兰明显增加穿越平台次数(P<0.01),缩短第一次到达平台时间(P<0.05),延长在目标象限探索的时间和路程(P<0.01)。ELISA分析结果显示,20月龄正常组小鼠海马c AMP水平明显低于6月龄正常组小鼠(P<0.01),氯比普兰能显著增加海马c AMP含量(P<0.01)。Western蛋白印迹结果显示,20月龄正常组小鼠海马内p-PKA和p-CREB的蛋白表达明显低于6月龄正常组小鼠(P<0.01),氯比普兰能够增强p-PKA和p-CREB表达(P<0.01)。RTPCR结果表明,20月龄正常组小鼠海马内BDNF mRNA水平明显低于6月龄正常组小鼠(P<0.01),给予氯比普兰能显著提高BDNF mRNA水平(P<0.01)。结论氯比普兰可以通过影响c AMP水平,上调p-PKA和p-CREB蛋白表达,促进BDNF的转录,从而改善老年小鼠的认知功能障碍。     

磷酸二酯酶4研究进展

环腺苷酸(cAMP)和环鸟苷酸(cGMP)对于细胞的许多功能有重要作用。磷酸二酯酶(PDEs)催化cAMP和cGMP水解开环分别生成AMP和GMP,这是细胞内降解cAMP和cGMP的唯一途径。PDEs可分为11个家族,其中有8个家族可以水解cAMP,包括能专一性地水解cAMP的PDE家族(如PDE4),和既可水解cAMP又可水解cGMP的PDE家族。PDE4同工酶主要存于在炎症细胞中。PDE4可分为A、B、C、D 4个亚家族,根据其N端的特殊结构,有长、短和超短三种形式。PDE4催化区三维结构的阐明有助于它们功能的研究和相关药物的设计。PDE4通过与其它蛋白如抑制蛋白、A激-酶锚定蛋白(AKAP)以及活化的C激酶1受体(RACK1)等相互作用使cAMP浓度区域化,选择性地调节各种细胞功能。PDE4作为一个治疗靶点,研究其选择性抑制剂具有重要的意义,可以用于治疗由炎症引起的疾病,如哮喘、慢性阻塞性肺疾病(COPD)、阿尔采末病(AD)、帕金森病(PD)和中风等由潜在的炎症引起神经元受损造成的中枢神经系统疾病。