cAMP/PKA/CREB信号通路调控组织器官细胞纤维化及中医药干预作用的研究进展

环磷酸腺苷（cAMP）通过活化cAMP依赖的蛋白激酶A（PKA）,使cAMP反元件结合蛋白（CREB）磷酸化,从而调节基因转录,广泛参与神经系统的学习记忆过程,而近年来研究显示cAMP/PKA/CREB信号通路参与组织器官细胞的纤维化过程。机体损伤后在其组织器官细胞修复过程中,细胞外基质异常增生谓之纤维化,纤维化可使肝、肺、肾及心等脏器组织功能下降。中医药在治疗纤维化等慢性复杂疾病过程中有独特的优势,而调节cAMP/PKA/CREB信号通路是其防治组织器官细胞纤维化的机制之一。     

nNOS基因在慢性吗啡作用的SK-N-SH细胞的表达及调控

cAMP和转录因子CREB磷酸化水平升高是慢性吗啡依赖及耐受形成的基础.对于CREB与其调控的下游基因在其中的表达变化研究较少.首次研究了在慢性吗啡诱导的SK-N-SH细胞CREB的DNA结合活性及nNOS基因表达变化.该细胞株以1.5∶1的比例表达μ及δ受体,故实验结果更可靠.     

cAMP反应元件结合蛋白与神经退行性疾病

cAMP反应元件结合蛋白(cAMP response elem ent b ind-ing prote in,CREB)是位于细胞核内的转录因子。CREB的活性受到信号通路中许多因子的调控。CREB活化后与真核生物靶基因CRE序列结合并调节其转录,发挥多种生物学效应。在中枢神经系统,CREB调节着神经细胞生长发育,参与神经细胞突触可塑性、长时程记忆的形成过程。CREB参与阿尔采末病、血管性痴呆、亨廷顿舞蹈病及H IV-相关痴呆等神经退行性疾病的病理生理机制研究也取得了进展,成为以CREB作为靶点控制神经退行性疾病病程的理论基础。     

在脑缺血过程中CREB和cAMP反应元件介导的基因表达

环腺苷酸(cAMP)反应元件结合蛋白(CREB)是所有细胞生长、增值、分化、存活所必须的,在所有器官中均有表达。在脑中,CREB和cAMP反应元件(CRE)介导的信号系统参     

磷酸二酯酶抑制剂与学习记忆相关信号转导通路研究进展

大量的研究表明,环磷酸腺苷反应元件结合蛋白(cAMP response element binding protein,CREB)直接或间接激活相关基因转录,进而表达c-fos、c-jun、BDNF等,在神经元应激损伤后的再生、存活及修复以及学习记忆等方面发挥重要作用。磷酸二酯酶可以水解环磷酸腺苷(cyclic AMP,cAMP)及环磷酸鸟苷(cyclic GMP,cGMP),进而影响其下游信号转导,发挥对CREB的调节作用。该文从磷酸二酯酶抑制剂与学习记忆相关信号通路的关系及在学习记忆障碍中发挥的作用予以综述,并由该通路入手对发现治疗神经退行性变疾病药物作用新靶点的可能性予以展望。     

CREB在血管新生、抗凋亡以及肺癌中的研究进展

cAMP反应元件结合蛋白（CREB）作为一种转录因子在长期记忆形成和多种恶性肿瘤的发生及治疗领域 已被广泛研究,本文就 CREB基因在血管新生、细胞增殖及抗凋亡、与尼古丁致癌过程的关联以及在肿瘤（尤其是肺 癌）中的研究进展进行综述,以期为今后 CREB家族蛋白的研究提供参考。     

慢性吗啡处理对大鼠交感神经节pCREB和CREB mRNA表达的影响

目的观察慢性吗啡(Mor)处理对大鼠交感神经节-颈上神经节(SCG)环腺苷酸反应元件结合蛋白(cAMP responseelement binding protein,CREB)磷酸化和mRNA表达的影响。方法 Wistar大鼠随机分成4组(正常对照组、吗啡急性给药组、吗啡依赖组、吗啡戒断组),免疫组织化学方法及RT-PCR法分别检测磷酸化的CREB(phosphorylated CREB,pCREB)和CREB mRNA在SCG中的表达。结果 (1)与正常对照组相比,吗啡急性给药组大鼠SCG中pCREB含量明显降低(P<0.05);(2)吗啡依赖组大鼠SCG中pCREB含量回到正常对照组水平,并有增高趋势(与正常对照组比较,P>0.05;与吗啡急性给药组比较,P<0.01);(3)吗啡戒断组大鼠SCG中pCREB含量明显高于正常对照组(P<0.01);(4)各组大鼠SCG的CREBmRNA表达无差异(P>0.05)。结论慢性吗啡处理大鼠交感神经节CREB磷酸化水平存在适应性上调现象。     

cAMP反应元件结合蛋白在LPS致肺微血管内皮细胞损伤过程中的作用

目的探讨cAMP反应元件结合蛋白(cAMP response element binding protein,CREB)在脂多糖(lipopolysaccharide,LPS)致大鼠肺微血管内皮细胞(rat pulmonary microvascular endothelial cell,RPMVEC)炎症损伤过程中的作用。方法体外分离、培养RPMVEC基础上,Western blot法检测CREB磷酸化CREB水平,伊文思蓝-白蛋白法检测RPMVEC通透性。结果 LPS刺激RPMVEC后,CREB中Ser133位点磷酸化水平呈时间依赖性地增加,30 min时达到峰值,120 min仍未降至正常水平,加入10μmol·L-1V5681(PKA通路特异性抑制剂)共孵育后,CREB磷酸化几乎被完全抑制,RPMVEC单层通透性明显增加。结论 LPS能诱导RPMVEC中CREB快速磷酸化,PKA通路介导上述过程,CREB在LPS致RPMVEC炎症损伤过程中可能起到保护作用。     

羟甲芬太尼立体异构体对培养的海马神经元cAMP-反应元件结合蛋白磷酸化的影响

AIM: To define the effects and signal pathways of ohmefentanyl stereoisomers [(-)-cis-(3R,4S,2'R) OMF (F9202),( )-cis-(3R,4S,2'S) OMF (F9204), and (-)-cis-(3S,4S,2'R) OMF (F9203)] on the phosphorylation of cAMP-re-sponse element binding protein (CREB) in cultured rat hippocampal neurons. METHODS: The effects of the three OMF stereoisomers and morphine (Mor) on cAMP accumulation and CREB phosphorylation were monitored by radioimmunoassay and Western blot analysis, respectively. RESULTS: The three OMF stereoisomers and Mor could all partially inhibit forskolin-stimulated (25μmol/L, 15min) cAMP accumulation in a dose-dependent manner and this effect could be reversed by naloxone. F9202, F9204, and Mor could significantly increase CREB phosphorylation from 2.88 to 3.59 folds over control levels after 30-min exposure. This effect was reversed by naloxone,but F9203 failed to increase CREB phosphorylation. KN-62 and staurosporine significantly blocked the opioidsinduced CREB phosphorylation, while H-89 and PD 98059 had no effect on the actions. CONCLUSION: Mor,F9202, and F9204, which could induce psychological dependence affected via the μ-opioid receptor, stimulated intracellular signal pathways involving Ca^2 /calmodulin-dependent protein kinases (CCDPK) and protein kinase C(PKC) pathways, which in turn initiated CREB phosphorylation. F9203, which could not induce dependence, had no effect on CREB phosphorylation in hippocampal neurons. The increased CREB phosphorylation in hippocampal neurons may play a role in opioids dependence.     

抑郁症信号转导通路研究

长期给予抗抑郁剂可以增加脑内cAMP依赖性PKA的表达水平,继而激活cAMP反应元件结合蛋白。CREB可以调节脑源性神经生长因子的表达。大量的研究表明cAMP和BDNF是多种抗抑郁剂的共同通路,现就此进行综述,探讨其与抗抑郁剂之间的关系,为精神药理和新药研发提供依据。     

The mechanisms of morphine dependence and it's withdrawal syndrome: study in mutant mice

To investigate the involvement of catecholamines and/or the cyclic AMP (cAMP) systems in the development of drug dependence, we examined whether morphine dependence was developed in tyrosine hydroxylase (TH) heterozygous (TH+/-) and cAMP response element binding protein (CREB) binding protein (CBP) heterozygous (CBP+/-) mice. Morphine (10 mg/kg) induced place preference in the wild-type mice. In the TH+/- and CBP+/- mice, however, we could not find any morphine-induced place preference. When the wild-type mice pretreated with morphine (10 mg/kg) twice a day for 5 days were challenged with naloxone (5 mg/kg), they showed increased numbers of jumping, rearing and forepaw tremor as a sign of withdrawal symptom and increased level of cAMP in the thalamus/hypothalamus, but not in the striatum. However, increased numbers of jumping and forepaw tremor in the TH+/- and CBP+/- mice and increased level of cAMP in the thalamus/hypothalamus of TH+/- mice were not observed. These results suggest that catecholamines and CBP are involved in the development of morphine dependence, and that some changes in the catecholaminergic and/or cAMP system induced by repeated morphine treatment play an important role in the addiction of morphine.     

Inhibitory effects of ginseng total saponin on up-regulation of cAMP pathway induced by repeated administration of morphine

We have reported that ginseng total saponin (GTS) inhibited the development of physical and psychological dependence on morphine. However, the possible molecular mechanisms of GTS are unclear. Therefore, this study was undertaken to understand the possible molecular mechanism of GTS on the inhibitory effects of morphine-induced dependence. It has been reported that the up-regulated cAMP pathway in the LC of the mouse brain after repeated administration of morphine contributes to the feature of withdrawals. GTS inhibited up-regulation of cAMP pathway in the LC after repeated administration of morphine in this experiment. GTS inhibited cAMP levels and protein expression of protein kinase A (PKA). In addition, GTS inhibited the increase of cAMP response element binding protein (CREB) phosphorylation. Therefore, we conclude that the inhibitory effects of GTS on morphine-induced dependence might be mediated by the inhibition of cAMP pathway.     

Role of catecholaminergic and cyclic AMP systems in psychological dependence on phencyclidine: a study in mutant mice

Catecholaminergic and/or cyclic AMP (cAMP) systems have been demonstrated to be involved in the development of drug dependence. We investigated the involvement of both systems in psychological dependence on phencyclidine (PCP) by using tyrosine hydroxylase (TH) heterozygous (TH+/-) and cAMP response element binding protein (CREB) binding protein (CBP) heterozygous (CBP+/-) mice. PCP (8 mg/kg) induced place preference in wild-type mice pretreated with PCP (10 mg/kg once a day for 28 days). In these mice, the level of cAMP in the striatum, but not in the thalamus, was increased one day after the last injection of PCP (10 mg/kg). In TH+/- and CBP+/- mice pretreated with PCP (10 mg/kg per day for 28 days), however, no PCP (8 mg/kg)-induced place preference was observed. The level of cAMP in the striatum was increased in CBP+/- mice, but not TH+/- mice. Furthermore, we have demonstrated that the place preference induced by PCP is attenuated by 6-hydroxydopamine, a dopaminergic neurotoxin, and (+) SCH-23390, a dopamine-D1 receptor antagonist, but not by DSP-4, a noradrenergic neurotoxin, and (-) sulpiride, a dopamine-D2 receptor antagonist. These findings suggest that catecholamines and CBP are involved in the development of psychological dependence on PCP and that changes in dopaminergic and/or cAMP systems induced by repeated PCP treatment play an important role in the addiction to PCP.     

Transcriptional regulation of mu opioid receptor gene by cAMP pathway

The utility of morphine for the treatment of chronic pain is hindered by the development of tolerance. Fentanyl has been shown to be a potent analgesic with a lower propensity to produce tolerance and physical dependence in the clinical setting. Previous finding has shown that fentanyl induces mu opioid receptor gene expression in PC-12 cells (Brain Res 859:217-223, 2000). In this report, we aim to identify the molecular mechanism of mu-opioid receptor (MOR) gene regulation by fentanyl. We demonstrated that the 4.7-kilobase MOR promoter could be induced by fentanyl in PC-12 cells, and we defined a partial cAMP response element (CRE) located at -106/-111 in 5'-untranslated region of the MOR gene. In electrophoretic mobility shift assay, cAMP response element-binding protein (CREB) was found in the protein-DNA complex formed on the CRE box. CREB was phosphorylated after forskolin induction, and both CREB and CREB-binding protein (CBP) binding to the endogenous MOR promoter was increased by forskolin in chromatin immunoprecipitation assay. The functional role of CREB in the induction of MOR gene was further elucidated by an experiment in which a dominant-negative mutant CREB, CREB-S133A, abolished the forskolin-mediated MOR induction. Moreover, we found that this CRE box is conserved in mouse, rat, and human MOR gene, implying physiological relevance in different species. Collectively, this study demonstrated that fentanyl-triggered MOR gene induction was mediated by the sequential activation of CREB and the binding of CREB and CBP to MOR promoter, thus provides direct evidence for lower propensity of fentanyl to produce tolerance.     

Learning/memory and drug dependence

We investigated the possible mechanisms of development of latent learning and morphine dependence by the methods of behavioral pharmacology and confirmed them by using mutant mice. The heterozygous mice for the tyrosine hydroxylase (TH) gene and for the cyclic AMP (cAMP) response element binding protein (CREB) binding protein (CBP) gene showed the impairment of latent learning in the water finding task, and these mice did not develop morphine dependence. The spatial learning and hippocampal long-term potentiation (LTP) were normal in the both mutants. TH heterozygous mice showed a reduction of high K(+)-evoked noradrenaline release in the frontal cortex measured by the microdialysis technique and of cAMP content in the brain. In conclusion, the results of mutant mice suggest that the alternation of catecholamine biosynthesis and cAMP signal pathways may play a key role in development of latent learning and morphine dependence, and they furthermore show that the expression of genes mediated by phosphorylated CREB may be involved in the development of latent learning and morphine dependence.