选择性磷酸二酯酶抑制剂罗氟司特在慢性阻塞性肺疾病抗炎作用的研究进展

磷酸二酯酶4(Phosphodiesterase 4,PDE4)、特异性水解环磷酸腺苷(cyclic adenosine monophosphate,cAMP),广泛存在于多种炎症细胞及结构细胞中.选择性抑制PDE4使细胞内cAMP浓度增加,呈现抗炎作用.第二代PDE4抑制剂罗氟司特(roflumilast)具有抑制中性粒细胞、T细胞、巨噬细胞等多种炎症细胞及TNF-α、LTB4、活性氧、IFN-γ等多种炎症介质的抗炎作用,成为第一个应用于慢性阻塞性肺疾病临床治疗的PDE4抑制剂.罗氟司特的抗炎效果可能与炎症类型、药物剂量、免疫形式等影响因素有关.     

磷酸二酯酶抑制剂在哮喘治疗中的新进展

1PDE的结构与功能环磷酸腺苷(cAMP)和环磷酸鸟苷(cGMP)是细胞内重要的第二信使,介导许多生理过程。高浓度的cAMP与特异性蛋白激酶结合,进一步活化这些激酶,导致各种底物磷酸化,调节细胞反应cAMP的水平由合成和降解的比例来调节。合成由腺苷环化酶和鸟苷环化酶,通过G蛋白受体耦联活化后水解ATP,GTP形成;降解则由磷酸二酯酶(PDE)负责。PDE是个蛋白酶超家族,至今已鉴定出PDE有11个家族成员[1],它们的原始序列、底物特异性、辅助因子及对抑制剂敏感性不同,其中PDE3、PDE4、PDE5、PDE7主要分布于炎症和免疫细胞中,与人类炎症反…     

选择性磷酸二酯酶抑制剂罗氟司特在慢性阻塞性肺疾病抗炎作用的研究进展

磷酸二酯酶4(Phosphodiesterase 4,PDE4)、特异性水解环磷酸腺苷(cyclic adenosine monophosphate,cAMP),广泛存在于多种炎症细胞及结构细胞中。选择性抑制PDE4使细胞内cAMP浓度增加,呈现抗炎作用。第二代PDE4抑制剂罗氟司特(roflumilast)具有抑制中性粒细胞、T细胞、巨噬细胞等多种炎症细胞及TNF-α、LTB4、活性氧、IFN-γ等多种炎症介质的抗炎作用,成为第一个应用于慢性阻塞性肺疾病临床治疗的PDE4抑制剂。罗氟司特的抗炎效果可能与炎症类型、药物剂量、免疫形式等影响因素有关。     

磷酸二酯酶4抑制剂在肺疾病治疗中的前景

磷酸二酯酶 (PDE)是催化水解细胞内第二信使分子环核苷酸 [环磷酸腺苷 (cAMP)及环磷酸鸟苷 (cGMP) ]的超级酶家族。根据特殊激动剂和抑制剂的特异性、敏感性、酶动力学特性及一级氨基酸序列的不同进行分类 ,目前已认定了PDE的 11个家族成员 ,而且还会不断扩大[1];每一成员均存在编码 2个或 2个以上亚型的基因 ,各亚型基因又有 2个或更多的变异体 ,构成复杂的PDE蓝图。cAMP特异性同工酶即磷酸二酯酶 4(PDE4)几乎在所有免疫和炎性细胞中广泛表达 ,选择性抑制PDE4 能调节免疫和炎性细胞活性 ,呈现抗炎作用 ,在炎性疾病治疗中渐受重视…     

选择性磷酸二酯酶抑制剂在气道炎症性疾病中的作用

磷酸二酯酶 4 (PDE4 )对于调节细胞内cAMP和cGMP的浓度有重要作用。早期的PDE4抑制剂在体内、体外试验中均有明确的抗炎和支气管扩张作用。但由于它的胃肠道副作用 ,临床使用受到了限制。现已研制出新一代的选择性PDE4抑制剂 ,如cilomilast和roflumilast。它们保留了早期PDE4抑制剂的抗炎和支气管扩张作用 ,又减少了副作用。现在已经公布了用于哮喘和慢性阻塞性肺疾病 (COPD)的临床试验结果。     

选择性磷酸二酯酶抑制剂在气道炎症性疾病中的作用

磷酸二酯酶4(PDE4)对于调节细胞内cAMP和cGMP的浓度有重要作用。早期的PDE4抑制剂在体内、体外试验中均有明确的抗炎和支气管扩张作用。但由于它的胃肠道副作用，临床使用受到了限制。现已研制出新一代的选择性PDE4抑制剂，如cilomilast和roflumilast。它们保留了早期PDE4抑制剂的抗炎和支气管扩张作用，又减少了副作用。现在已经公布了用于哮喘和慢性阻塞性肺疾病(COPD)的临床试验结果。     

罗氟司特治疗慢性阻塞性肺疾病的研究进展

<正>治疗慢性阻塞性肺疾病(COPD)主要以糖皮质激素及支气管舒张剂(如β2受体激动剂、抗胆碱药及甲基黄嘌呤类)为主,但仍有频发加重,因此要探求新的治疗方法。磷酸二酯酶-4(PDE4)抑制剂可通过抑制细胞内环磷酸腺苷降解来减轻炎症,2010年4月欧洲人用药品委员会推荐批准罗氟司特(一种选择性PDE4抑制剂),可用于伴慢性支气管炎且有频繁加重史的重度COPD患者附加于支气管舒张剂治疗上的维持治     

内分泌腺体中磷酸二酯酶的分布及作用研究进展

磷酸二酯酶(PDEs)是细胞内的一类水解酶家族,可催化细胞内环磷酸腺苷(cAMP)和环磷酸鸟苷(cGMP)的水解,分别产生5′-单磷酸腺苷(5′-AMP)和5′-单磷酸鸟苷(5′-GMP),它们作为cAMP及cGMP细胞内浓度及生物学效应的关键调控因子,在多分子信号/调控复合物信号体的形成和功能中起着重要作用。因此,P...     

环氧化酶及前列腺素D2、E2在支气管哮喘发病机制中的作用研究进展

支气管哮喘是最常见的慢性呼吸道疾病之一,是由嗜酸粒细胞、肥大细胞和T细胞等多种炎症细胞参与的气道慢性非特异性炎症.目前哮喘的病因和发病机制尚未完全阐明,近年来研究发现,环氧化酶( COX)和前列腺素(PGs)家族中的PGE2、PGD2在支气管哮喘发病机制中发挥重要作用.现综述如下.     

磷酸二酯酶4D SNP与缺血性脑卒中的相关性

磷酸二酯酶(PDEs)是一个多基因家族。PDEs催化环腺苷酸(cAMP)和环鸟苷酸(cGMP)分别生成AMP和GMP,这是细胞内降解cAMP和cGMP的唯一途径。PDEs可以分为11个家族,分别为1～11,其中PDE4能特异性地水解cAMP。PDE4又可以分为A、B、C和D 4个亚家族。关于PDE4D基因与缺血性脑卒中相关性的研究结果不一致。本文将就PDE4D和缺血性脑卒中的研究进展做一综述。     

Phosphodiesterase inhibition in heart failure

Drugs that inhibit cyclic nucleotide phosphodiesterase activity act to increase intracellular cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) content. In total, 11 families of these enzymes—which differ with respect to affinity for cAMP and cGMP, cellular expression, intracellular localization, and mechanisms of regulation—have been identified. Inhibitors of enzymes in the PDE3 family of cyclic nucleotide phosphodiesterases raise intracellular cAMP content in cardiac and vascular smooth muscle, with inotropic and, to a lesser extent, vasodilatory actions. These drugs have been used for many years in the treatment of patients with heart failure, but their long-term use has generally been shown to increase mortality through mechanisms that remain unclear. More recently, inhibitors of PDE5 cyclic nucleotide phosphodiesterases have been used as cGMP-raising agents in vascular smooth muscle. With respect to cardiovascular disease, there is evidence that these drugs are more efficacious in the pulmonary than in the systemic vasculature, for which reason they are used principally in patients with pulmonary hypertension. Effects attributable to inhibition of myocardial PDE5 activity are less well characterized. New information indicating that enzymes from the PDE1 family of cyclic nucleotide phosphodiesterases constitute the majority of cAMP- and cGMP-hydrolytic activity in human myocardium raises questions as to their role in regulating these signaling pathways in heart failure.     

Platelet cyclic adenosine monophosphate phosphodiesterases: targets for regulating platelet-related thrombosis

Platelets contain two cyclic adenosine monophosphate (cAMP) phosphodiesterases (PDEs) that regulate the level of cAMP, the major inhibitor of platelet activation pathways. PDE3A hydrolyzes cAMP to 5' AMP with a low K (m). PDE3A is inhibited by cyclic guanosine monophosphate (cGMP), which provides a feedback control and controls basal levels of cAMP. In contrast, PDE2A hydrolyzes both cAMP and cGMP with a high K (m), is allosterically stimulated by cGMP at moderate levels, and may control the stimulated levels of cAMP. Using affinity labeling, chemical modification, and site-directed mutagenesis of highly conserved amino acids, the amino acids required for catalytic activity and/or metal binding are H752 and H756. The singular binding sites for cAMP include N845, E971, and F972, whereas the unique amino acids interacting with cGMP are Y751, H836, H849, and D950. Residues E866 and F1004 are present in both the overlapping cGMP and cAMP sites. Two inhibitors of PDE3A are used in clinical medicine: milrinone and cilostazol. Three amino acids, Y751, D950, and F1004, show decreased sensitivity to both inhibitors (increased K (i)). These inhibitors mimic cGMP as an inhibitor of PDE3A rather than compete for cAMP binding. New nonhydrolyzable affinity labels inactivate PDE3A and are protected by Sp-cAMPS, a nonhydrolyzable substrate of the enzyme. These compounds have the potential to identify amino acids that are unique for PDE3A. An inhibitor of platelet PDE2A increases cAMP more than inhibitors of PDE3A but has much less effect on platelet activation, suggesting that these enzymes are present in different compartments of the cell.     

Phosphodiesterase‐4 inhibition as a therapeutic strategy for metabolic disorders

Phosphodiesterase‐4 (PDE4) hydrolyses cyclic adenosine monophosphate (cAMP), a crucial secondary messenger for cellular adaptation to diverse external stimuli. The activity of PDE4 is tightly controlled by post‐translational regulation, structure‐based auto‐regulation and locus specific ‘compartmentalization’ of PDE4 with its interactive proteins (signalsomes). Through these mechanisms, PDE4 regulates cAMP levels and shapes the cAMP signalling, directing signals from the diverse external stimuli to distinct microenvironments exquisitely. Derangement of the PDE4‐cAMP signalling represents a pathophysiologically relevant pathway in metabolic disorders as demonstrated through a critical role in the processes including inflammation, disordered glucose and lipid metabolism, hepatic steatosis, abnormal lipolysis, suppressed thermogenic function and deranged neuroendocrine functions. A limited number of PDE4 inhibitors are currently undergoing clinical evaluation for treating disorders such as type 2 diabetes and non‐alcoholic steatohepatitis. The discovery of novel PDE4 allosteric inhibitors and signalsome‐based strategies targeting individual PDE4 variants may allow PDE4 isoform selective inhibition, which may offer safer strategies for chronic treatment of metabolic disorders. © 2016 World Obesity     

Treating COPD with PDE 4 inhibitors

While the pathogenesis of chronic obstructive pulmonary disease (COPD) is incompletely understood, chronic inflammation is a major factor. In fact, the inflammatory response is abnormal, with CD8⁺ T-cells, CD68⁺ macrophages, and neutrophils predominating in the conducting airways, lung parenchyma, and pulmonary vasculature. Elevated levels of the second messenger cAMP can inhibit some inflammatory processes. Theophylline has long been used in treating asthma; it causes bronchodilation by inhibiting cyclic nucleotide phosphodiesterase (PDE), which inactivates cAMP. By inhibiting PDE, theophylline increases cAMP, inhibiting inflammation and relaxing airway smooth muscle. Rather than one PDE, there are now known to be more than 50, with differing activities, substrate preferences, and tissue distributions. Thus, the possibility exists of selectively inhibiting only the enzyme(s) in the tissue(s) of interest. PDE 4 is the primary cAMP-hydrolyzing enzyme in inflammatory and immune cells (macrophages, eosinophils, neutrophils). Inhibiting PDE 4 in these cells leads to increased cAMP levels, down-regulating the inflammatory response. Because PDE 4 is also expressed in airway smooth muscle and, in vitro, PDE 4 inhibitors relax lung smooth muscle, selective PDE 4 inhibitors are being developed for treating COPD. Clinical studies have been conducted with PDE 4 inhibitors; this review concerns those reported to date.     

Elevated cyclic AMP and PDE4 inhibition induce chemokine expression in human monocyte-derived macrophages

Macrophages are central mediators of the innate immune system that can be differentiated from monocytes upon exposure to cytokines. While increased cyclic adenosine monophosphate (cAMP) levels are known to inhibit many lipopolysaccharide-elicited macrophage inflammatory responses, the effects of elevated cAMP on monocyte/macrophage differentiation are not as well understood. We show here that during differentiation, cAMP agonists can cause a large increase in the mRNA and protein levels of several of the pro-inflammatory CXCL and CCL chemokines. The cAMP mediator-exchange protein activated by cAMP (Epac) contributes substantially to the increase in these chemokines. These chemokines are known to play an important role in the regulation of immune responses, particularly regarding the pathogenesis of asthma and chronic obstructive pulmonary disorder. We also found that a selective cAMP-degrading phosphodiesterase (PDE) 4 inhibitor can potentiate the chemokine expression elicited by low-dose forskolin or Prostaglandin E2 (PGE₂). These data suggest that chemokine receptor antagonists administered in conjunction with a PDE4 inhibitor may improve both the efficacy and safety of PDE4-inhibitor therapy for chronic inflammatory disorders.     

PDE3 cyclic nucleotide phosphodiesterases and the compartmentation of cyclic nucleotide-mediated signalling in cardiac myocytes

PDE3 cyclic nucleotide phosphodiesterase inhibitors raise cAMP and cGMP content in cardiac and vascular myocytes. Their administration to patients with dilated cardiomyopathy leads to improvements in hemodynamic parameters in the short term but reduces survival with chronic administration. The reasons for this 'biphasic' response have not been elucidated, but it is likely that beneficial and harmful effects of PDE3 inhibition reflect the phosphorylation of different substrates of cAMP- and cGMP-dependent protein kinases (PK-A and PK-G). It is now apparent that cardiac and vascular myocytes contain several isoforms of PDE3 that differ in their intracellular distribution and thus regulate cAMP and cGMP levels in different subcellular compartments. These isoforms also differ in their regulation by extracellular signals that may be important in the pathophysiology of dilated cardiomyopathy. An intriguing possibility is that the beneficial and harmful effects of PDE3 inhibition may be attributable to the inhibition of different isoforms of these enzymes.     

Insulin increases cyclic nucleotide content in human vascular smooth muscle cells: a mechanism potentially involved in insulin-induced modulation of vascular tone

Summary It has been suggested that insulin exerts a vasodilating effect, but the mechanisms involved are not completely understood. Since cyclic nucleotides mediate the vasodilation induced by endogenous substances, such as prostacyclin and nitric oxide, we aimed to investigate the influence of insulin (concentration range 240–960 pmol/l) on both cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) content in human vascular smooth muscle cells. Insulin dose-dependently increased both nucleotides (cAMP: from 0.7±0.1 to 2.6±0.4 pmol/10⁶ cells, p=0.0001; cGMP: from 1.3±0.2 to 3.4±0.7 pmol/10⁶ cells, p=0.033). This increase is receptor-mediated, since it was blunted when cells were preincubated with the tyrosine kinase inhibitor genistein. The effect of insulin remained significant (p=0.0001) when preincubation with the phosphodiesterase inhibitor theophylline prevented cyclic nucleotide catabolism. The increase of cGMP was blunted when the cells were preincubated with the guanylate cyclase inhibitor methylene blue, and with the nitric oxide-synthase inhibitor N^G-monomethyl-l-arginine. At all the concentrations tested, insulin potentiated the increase of cAMP induced by the stable prostacyclin analogue Iloprost (p=0.0001), whereas only at 1920 pmol/l did it potentiate the cGMP increase induced by glyceryltrinitrate (p=0.05). This study demonstrates that the vasodilating effects exerted by insulin may at least in part be attributable to an increase of both cGMP and cAMP via a receptor-mediated activation of adenylate and guanylate cyclases in human vascular smooth muscle cells and that the insulin effect on cGMP is mediated by nitric oxide.Abbreviations cAMP cyclic adenosine monophosphate - cGMP cyclic guanosine monophosphate - PDE phosphodiesterases - NO nitric oxide - hVSMC human vascular smooth muscle cells - l-NMMA N^G-monomethyl-l-arginine - GTN glyceryltrinitrate - BSA bovine serum albumin - NIDDM non-insulin-dependent diabetes mellitus - MEM minimal essential medium - RIA radioimmunoassay     

Control of renin secretion from rat juxtaglomerular cells by cAMP-specific phosphodiesterases

We tested the hypothesis that cGMP stimulates renin release through inhibition of the cAMP-specific phosphodiesterase 3 (PDE3) in isolated rat juxtaglomerular (JG) cells. In addition, we assessed the involvement of PDE4 in JG-cell function. JG cells expressed PDE3A and PDE3B, and the PDE3 inhibitor trequinsin increased cellular cAMP content, enhanced forskolin-induced cAMP formation, and stimulated renin release from incubated and superfused JG cells. Trequinsin-mediated stimulation of renin release was inhibited by the permeable protein kinase A antagonist Rp-8-CPT-cAMPS. PDE4C was also expressed, and the PDE4 inhibitor rolipram enhanced cellular cAMP content. Dialysis of single JG cells with cAMP in whole-cell patch-clamp experiments led to concentration-dependent, biphasic changes in cell membrane capacitance (C(m)) with a marked increase in C(m) at 1 micromol/L, no net change at 10 micromol/L, and a decrease at 100 micromol/L cAMP. cGMP also had a dual effect on C(m) at 10-fold higher concentration compared with cAMP. Trequinsin, milrinone, and rolipram mimicked the effect of cAMP on C(m). Trequinsin, cAMP, and cGMP enhanced outward current 2- to 3-fold at positive membrane potentials. The effects of cAMP, cGMP, and trequinsin on C(m) and cell currents were abolished by inhibition of protein kinase A with Rp-cAMPs. We conclude that degradation of cAMP by PDE3 and PDE4 contributes to regulation of renin release from JG cells. Our data provide evidence at the cellular level that stimulation of renin release by cGMP involves inhibition of PDE3 resulting in enhanced cAMP formation and activation of the cAMP sensitive protein kinase.     

The preclinical pharmacology of roflumilast – A selective,oral phosphodiesterase 4 inhibitor in development for chronic obstructive pulmonary disease

After more than two decades of research into phosphodiesterase 4 (PDE4) inhibitors, roflumilast (3-cyclopropylmethoxy-4-difluoromethoxy-N-[3,5-di-chloropyrid-4-yl]-benzamide) may become the first agent in this class to be approved for patient treatment worldwide. Within the PDE family of 11 known isoenzymes, roflumilast is selective for PDE4, showing balanced selectivity for subtypes A–D, and is of high subnanomolar potency. The active principle of roflumilast in man is its dichloropyridyl N-oxide metabolite, which has similar potency as a PDE4 inhibitor as the parent compound. The long half-life and high potency of this metabolite allows for once-daily, oral administration of a single, 500-μg tablet of roflumilast.The molecular mode of action of roflumilast – PDE4 inhibition and subsequent enhancement of cAMP levels – is well established. To further understand its functional mode of action in chronic obstructive pulmonary disease (COPD), for which roflumilast is being developed, a series of in vitro and in vivo preclinical studies has been performed.COPD is a progressive, devastating condition of the lung associated with an abnormal inflammatory response to noxious particles and gases, particularly tobacco smoke. In addition, according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD), significant extrapulmonary effects, including comorbidities, may add to the severity of the disease in individual patients, and which may be addressed preferentially by orally administered remedies. COPD shows an increasing prevalence and mortality, and its treatment remains a high, unmet medical need.In vivo, roflumilast mitigates key COPD-related disease mechanisms such as tobacco smoke-induced lung inflammation, mucociliary malfunction, lung fibrotic and emphysematous remodelling, oxidative stress, pulmonary vascular remodelling and pulmonary hypertension. In vitro, roflumilast N-oxide has been demonstrated to affect the functions of many cell types, including neutrophils, monocytes/macrophages, CD4+ and CD8+ T-cells, endothelial cells, epithelial cells, smooth muscle cells and fibroblasts. These cellular effects are thought to be responsible for the beneficial effects of roflumilast on the disease mechanisms of COPD, which translate into reduced exacerbations and improved lung function. As a multicomponent disease, COPD requires a broad therapeutic approach that might be achieved by PDE4 inhibition. However, as a PDE4 inhibitor, roflumilast is not a direct bronchodilator.In summary, roflumilast may be the first-in-class PDE4 inhibitor for COPD therapy. In addition to being a non-steroid, anti-inflammatory drug designed to target pulmonary inflammation, the preclinical pharmacology described in this review points to a broad functional mode of action of roflumilast that putatively addresses additional COPD mechanisms. This enables roflumilast to offer effective, oral maintenance treatment for COPD, with an acceptable tolerability profile and the potential to favourably affect the extrapulmonary effects of the disease.     

Sildenafil and vardenafil,types 5 and 6 phosphodiesterase inhibitors,induce caspase-dependent apoptosis of B-chronic lymphocytic leukemia cells

Type 4 phosphodiesterase (PDE4) inhibitors reportedly induce apoptosis in chronic lymphocytic leukemia (CLL) cells. Following clinical improvement of one previously untreated CLL patient with sildenafil therapy, we evaluated the in vitro induction of apoptosis in CLL cells by 4 PDE5/6 inhibitors, including sildenafil, vardenafil, zaprinast, and methoxyquinazoline (MQZ). After 24 hours of culture, the various PDE inhibitors differed in their ability to induce apoptosis, with zaprinast displaying no killing effect. Normal B cells isolated from control donors were totally resistant to PDE-induced apoptosis. Vardenafil was 3 and 30 times more potent an inducer of apoptosis than sildenafil and MQZ, respectively. Both vardenafil and sildenafil failed to elevate adenosine 3'5' cyclic monophosphate (cAMP) levels, largely excluding an inhibitory effect on cAMP-PDE3, -PDE4, and -PDE7. Vardenafil- or sildenafil-treated B-CLL cells displayed up to 30% intracellular active caspase 3. Drug-induced apoptosis was inhibited by the caspase inhibitor z-VAD.fmk, prevented by interleukin-4 (IL-4), and significantly reduced by stromal-derived factor1-alpha (SDF-1alpha). We conclude that vardenafil and sildenafil induce caspase-dependent apoptosis of B-CLL cells in vitro and thus might be considered in the treatment of CLL patients. However, further in vivo investigations should be warranted.