Epac信号分子与哮喘关系研究进展

支气管哮喘是临床常见的气道慢性炎症性疾病,以气道高反应性、慢性气道炎症和气道重塑为病理生理特征,其发病机制目前尚未完全阐明。环磷酸腺苷(cAMP)是体内重要的第二信使,参与调控机体新陈代谢、细胞钙信号传导、细胞生长与分化、凋亡等多种病理生理过程。长期以来,蛋白激酶A (PKA)被认为是介导cAMP生物学效应的唯一下游信号分子。但新近发现的新型cAMP靶分子——cAMP直接激活的交换蛋白(Epac)的发现打破了这一说法。大量研究证实,Epac可单独或协同PKA介导cAMP的多种生物学效应。本文就Epac在支气管哮喘发病中的作用及其可能机制作一综述,为寻找哮喘治疗新靶点奠定基础。     

miR-483/CREB1轴介导桃叶珊瑚苷抑制髓核细胞胞外基质降解的研究

目的研究miR-483/CREB1轴在桃叶珊瑚苷(aucubin,AU)抑制人退行性髓核(nucleus pulposus,NP)细胞胞外基质(extracellular matrix,ECM)降解中的功能作用。方法AU处理人退行性NP细胞后,检测细胞活性、ECM相关蛋白及cAMP反应元件结合蛋白1(c AMP responsive element binding protein 1,CREB1)的表达。实时荧光定量PCR(quantitative real-time PCR,q PCR)和Western blot检测miR-483表达变化对CREB1丰度的影响;双荧光素酶报告实验(luciferase,LUC)检测miR-483和CREB1-3’-UTR的靶向结合;CREB1过表达载体和(或)miR-483 mimics共转染后,AU处理,检测CREB1及ECM相关蛋白的表达。结果AU可显著增强NP细胞活性(P=0.0004),抑制ECM降解酶基质金属蛋白酶-3(matrix metalloproteinase-3,MMP-3)、血小板反应蛋白解整合素金属肽酶-5(a disintegrin and metalloproteinase domain with thrombospondin motif-5,ADAMTS-5)与CREB1的表达,促进胶原蛋白Ⅱ型胶原α1(collagen type II alpha 1 chain,COL2A1)和miR-483的表达(P<0.001)。miR-483过表达可抑制CREB1的表达(P<0.0001),LUC实验表明miR-483可与CREB1-3’-UTR靶向结合。功能实验结果表明CREB1可削弱AU对NP细胞ECM的降解的抑制作用,而miR-483可部分逆转CREB1对AU的抑制作用。结论AU诱导NP细胞表达miR-483,进而抑制CREB1的表达,增强NP细胞的活性,抑制ECM的降解。     

海洋纤溶活性化合物FGFC1和FGFC2影响血小板聚集特性的研究

目的：研究新型海洋双吲哚纤溶活性化合物FGFC1对血小板聚集的影响,发现纤溶活性化合物FGFC1与血小板相关因子变化的关系,同时比较双吲哚化合物FGFC1和单吲哚化合物FGFC2作用于血小板的异同。方法：从新鲜兔血收集血小板,调整反应体系血小板密度,以乙酰水杨酸为阳性对照,采用微量比浊法分析FGFC1和FGFC2对血小板聚集率的影响,用酶联免疫法测定FGFC1和FGFC2对血小板生理因子含量的变化。结果：FGFC1对ADP和AA诱导的血小板聚集具有抑制作用,最大抑制率分别达到42.58%±1.7%和47.82%±2.18%;FGFC2对ADP、AA和胶原诱导的血小板聚集均具有抑制作用,最大抑制率分别为50.12%±1.02%、45.28%±1.09%和50.28%±2.12%。FGFC1与FGFC2均能提升血小板内环磷酸腺苷含量,且FGFC2能明显降低血小板内血栓素A2含量。结论：海洋双吲哚纤溶活性化合物显著抑制血小板聚集,FGFC1通过影响血小板环磷酸腺苷的含量实现抑制血小板聚集,FGFC2可能通过不止一种途径抑制血小板聚集。吲哚化合物抑制血小板聚集与分子结构密切相关。     

Tadalafil: 15 years' journey in male erectile dysfunction and beyond

Tadalafil, Cialis, Eli Lilly & Co./ICOS, (6R,12aR)-6-(1,3-benzodioxol-5-yl)-2-methyl-2,3,6,7,12,12a-hexahydropyrazino[1′,2′:1,6] pyrido[3,4-b]indole-1,4-dione, was first discovered in 2003. It was reported to have high diastereospecificity for phosphodiesterase 5 (PDE5) inhibitions. The cis-(6R, 12aR) enantiomer is the most active enantiomer. Tadalafil showed PDE5 inhibition with IC₅₀ = 5 nM. It possesses high selectivity for PDE5 versus PDE1-4 and PDE6. Tadalafil is more selective to PDE5 against PDE6 whereas sildenafil, another commercially available PDE5 inhibitor shows similar potencies to inhibit PDE5 and PDE6. Tadalafil is used for the treatment of male erectile dysfunction (MED), prostatic benign hyperplasia (PBH) signs and symptoms, and pulmonary arterial hypertension (PAH). Adcirca, another name for tadalafil, is used to treat PAH and improve exercise capacity. Recent clinical studies suggest the use of tadalafil for nonurological applications, including circulatory disorders (ischemia injury, myocardial infarction, cardiac hypertrophy, cardiomyopathy, heart failure, and stroke), neurodegenerative disorders, and cognitive impairment conditions. This review discusses tadalafil and its analogues reported in the past 15 years. It discusses synthetic pathways, structural activity relationships, existing and future pharmacological indications of tadalafil and its analogues. This work can help medicinal chemists developing novel PDE5 inhibitors with wider therapeutic indications.     

Control of bone resorption in mice by Schnurri-3

Mice lacking the large zinc finger protein Schnurri-3 (Shn3) display increased bone mass, in part, attributable to augmented osteoblastic bone formation. Here, we show that in addition to regulating bone formation, Shn3 indirectly controls bone resorption by osteoclasts in vivo. Although Shn3 plays no cell-intrinsic role in osteoclasts, Shn3-deficient animals show decreased serum markers of bone turnover. Mesenchymal cells lacking Shn3 are defective in promoting osteoclastogenesis in response to selective stimuli, likely attributable to reduced expression of the key osteoclastogenic factor receptor activator of nuclear factor-κB ligand. The bone phenotype of Shn3-deficient mice becomes more pronounced with age, and mice lacking Shn3 are completely resistant to disuse osteopenia, a process that requires functional osteoclasts. Finally, selective deletion of Shn3 in the mesenchymal lineage recapitulates the high bone mass phenotype of global Shn3 KO mice, including reduced osteoclastic bone catabolism in vivo, indicating that Shn3 expression in mesenchymal cells directly controls osteoblastic bone formation and indirectly regulates osteoclastic bone resorption.     

Small molecule antagonist reveals seizure-induced mediation of neuronal injury by prostaglandin E2 receptor subtype EP2

With interest waning in the use of cyclooxygenase-2 (COX-2) inhibitors for inflammatory disease, prostaglandin receptors provide alternative targets for the treatment of COX-2-mediated pathological conditions in both the periphery and the central nervous system. Activation of prostaglandin E2 receptor (PGE(2)) subtype EP2 promotes inflammation and is just beginning to be explored as a therapeutic target. To better understand physiological and pathological functions of the prostaglandin EP2 receptor, we developed a suite of small molecules with a 3-aryl-acrylamide scaffold as selective EP2 antagonists. The 12 most potent compounds displayed competitive antagonism of the human EP2 receptor with K(B) 2-20 nM in Schild regression analysis and 268- to 4,730-fold selectivity over the prostaglandin EP4 receptor. A brain-permeant compound completely suppressed the up-regulation of COX-2 mRNA in rat cultured microglia by EP2 activation and significantly reduced neuronal injury in hippocampus when administered in mice beginning 1 h after termination of pilocarpine-induced status epilepticus. The salutary actions of this novel group of antagonists raise the possibility that selective block of EP2 signaling via small molecules can be an innovative therapeutic strategy for inflammation-related brain injury.     

Early pregnancy induced expression of prostaglandin E2 receptors EP2 and EP4 in the ovine endometrium and regulated by interferon tau through multiple cell signaling pathways

Prostaglandin E2 (PGE₂) plays pleiotropic roles at fetal-maternal interface during establishment of pregnancy. The objectives of the study were to: (i) determine regulation of PGE2 receptors EP1, EP2, EP3, and EP4 in the endometrium during the estrous cycle and early pregnancy; and (ii) understand endometrial epithelial and stromal cell-specific hormonal regulation of EP2 and EP4 in sheep. Results indicate that: (i) early pregnancy induces expression of EP2 and EP4 but not EP1 and EP3 proteins in the endometrium on days 12-16 compared to that of estrous cycle; (ii) intrauterine infusion of interferon tau (IFNT) increases expression of EP2 and EP4 proteins in endometrium; and (iii) IFNT activates distinct epithelial and stromal cell-specific JAK, EGFR, ERK1/2, AKT, or JNK signaling module to regulate expression of EP2 and EP4 proteins in the ovine endometrium. Our results indicate a role for EP2 and EP4-mediated PGE₂ signaling in endometrial functions and establishment of pregnancy in ruminants.     

Somatostatin receptors: From signaling to clinical practice

Somatostatin is a peptide with a potent and broad antisecretory action, which makes it an invaluable drug target for the pharmacological management of pituitary adenomas and neuroendocrine tumors. Somatostatin receptors (SSTR1, 2A and B, 3, 4 and 5) belong to the G protein coupled receptor family and have a wide expression pattern in both normal tissues and solid tumors. Investigating the function of each SSTR in several tumor types has provided a wealth of information about the common but also distinct signaling cascades that suppress tumor cell proliferation, survival and angiogenesis. This provided the rationale for developing multireceptor-targeted somatostatin analogs and combination therapies with signaling-targeted agents such as inhibitors of the mammalian (or mechanistic) target of rapamycin (mTOR). The ability of SSTR to internalize and the development of rabiolabeled somatostatin analogs have improved the diagnosis and treatment of neuroendocrine tumors.