腺苷A1受体拮抗剂DPCPX对低氧复氧脑星形胶质细胞影响的实验研究

目的:观察腺苷A1受体拮抗剂1,3-二丙基-环戊黄嘌呤(8-cyclopentyl-1,3-dipropylxanthine, DPCPX)对体外培养低氧复氧(hypoxia and reoxygenation, H/R)大鼠脑星形胶质细胞促红细胞生成素(erythropoietin, EPO)释放量、谷氨酰胺合成酶(glutamine synthase, GS)、超氧化物歧化酶(superoxide dimutase, SOD)和谷胱甘肽过氧化物酶(glutathione peroxidase, GSH-PX)活性的影响,探讨腺苷A1受体在H/R星形胶质细胞神经保护中的作用.方法:对大鼠大脑皮层星形胶质细胞进行体外培养并建立H/R模型,在低氧同时加入终浓度为100 nmol/L DPCPX 12 h后复氧1,6,12,24 h,检测EPO释放量,GS,SOD和GSH-PX活性的变化.结果:与对照组比较,DPCPX组H/R星形胶质细胞的EPO释放量显著减少;GS,SOD和GSH-PX的活性降低.结论:腺苷A1受体参与H/R星形胶质细胞的神经保护作用.     

Hypoxia induces T-cell apoptosis by inhibiting chemokine C receptor 7 expression: the role of adenosine receptor A2

Hypoxia is a major characteristic of the tumor microenvironment, and its effects on immune cells are proposed to be important factors for the process of tumor immune escape. It has been reported that hypoxia affects the function of dendritic cells and the antitumor function of T cells. Here we discuss the effects of hypoxia on T-cell survival. Our results showed that hypoxia induced apoptosis of T cells. Adenosine and adenosine receptors (AR) are important to the hypoxia-related signaling pathway. Using AR agonists and antagonists, we demonstrated that hypoxia-induced apoptosis of T cells was mediated by A_2a and A_2b receptors. Furthermore, we are the first, to our knowledge, to report that hypoxia significantly inhibited the expression of chemokine C receptor 7 (CCR7) of T cells via the A₂R signal pathway, perhaps representing a mechanism of hypoxia-induced apoptosis of T cells. Collectively, our research demonstrated that hypoxia induces T-cell apoptosis by the A₂R signaling pathway partly by suppressing CCR7. Blocking the A₂R signaling pathway and/or activation of CCR7 can increase the anti-apoptosis function of T cells and may become a new strategy to improve antitumor potential.     

腺苷A2a受体在炎症反应中的作用

腺苷广泛分布于全身各组织器官,可通过与细胞表面相应G-蛋白偶联受体结合发挥抑制炎症反应,对抗缺血／缺氧和免疫调节等生物学作用。目前发现腺苷受体有4种亚型,即A1R、A2aR、A2bR和A3R。其中A2a腺苷受体（A2aR）广泛分布于神经胶质细胞,巨噬细胞,树突状细胞,肥大细胞,自然杀伤细胞等免疫细胞及内皮细胞和上皮细胞中,在相应的腺苷配体作用下,可通过腺苷-腺苷受体系统介导炎症反应和发挥免疫调节作用。     

腺苷A2A受体激动剂CGS21680对脂多糖诱导的小鼠急性肺损伤的保护作用

 目的：探讨腺苷A2A受体激动剂对脂多糖(LPS)诱导的急性肺损伤（ALI）小鼠的作用。方法：采用LPS（10 mg/kg）气管内注射6 h后的ALI小鼠模型。实验动物随机分为生理盐水对照组、ALI组、CGS21680治疗组和CGS21680对照组。测定各组6 h后肺湿重/干重比值（W/D）。比色法测定各组肺组织中髓过氧化物酶(MPO)活性。Western blotting分析各组肺组织中细胞间黏附分子1（ICAM-1）和血管细胞黏附分子1（VCAM-1）的表达。酶联免疫吸附法（ELISA）检测各组小鼠血清中单核细胞趋化蛋白1（MCP-1）的浓度。观察各组肺组织病理改变。结果：ALI组肺W/D、MPO活性、ICAM-1及VCAM-1表达和MCP-1浓度均较对照组显著升高。CGS21680治疗组前述各项指标较ALI组有显著下降。CGS21680组较对照组各项指标无显著差异。肺组织病理显示,ALI组可见肺间质明显充血水肿,大量炎症细胞浸润,部分肺泡腔内可见红细胞。CGS21680治疗组可显著改善肺组织的病理变化。结论：腺苷A2A受体激动剂CGS21680可明显减轻LPS诱导的ALI小鼠肺组织的炎症反应及肺组织水肿,提示腺苷A2A受体激动剂在急性肺损伤中具有保护作用。     

Early induction of c-Myc is associated with neuronal cell death

Neuronal cell cycle activation has been implicated in neurodegenerative diseases such as Alzheimer's disease, while the initiating mechanism of cell cycle activation remains to be determined. Interestingly, our previous studies have shown that cell cycle activation by c-Myc (Myc) leads to neuronal cell death which suggests Myc might be a key regulator of cell cycle re-entry mediated neuronal cell death. However, the pattern of Myc expression in the process of neuronal cell death has not been addressed. To this end, we examined Myc induction by the neurotoxic agents camptothecin and amyloid-β peptide in a differentiated SH-SY5Y neuronal cell culture model. Myc expression was found to be significantly increased following either treatment and importantly, the induction of Myc preceded neuronal cell death suggesting it is an early event of neuronal cell death. Since ectopic expression of Myc in neurons causes the cell cycle activation and neurodegeneration in vivo, the current data suggest that induction of Myc by neurotoxic agents or other disease factors might be a key mediator in cell cycle activation and consequent cell death that is a feature of neurodegenerative diseases.     

The effects of A1 and A2A adenosine receptor agonists on kainic acid excitotoxicity in the guinea pig cochlea

The present study aimed to clarify the protective effect of adenosine receptors against the excitotoxicity of cochlear afferent dendrites. The effects of 2-chloro-N6-cyclopentyladenosine (CCPA), an A1 adenosine receptor agonist, and 5′-N-cyclopropyl-carboxamidoadenosine (CPCA), an A2A adenosine receptor agonist, on cochlear excitotoxicity induced by kainic acid (KA) were examined using guinea pigs. KA was applied to the round window membrane at a concentration of 10 mM for 30 min. CCPA or CPCA was given at the onset of KA application. KA morphologically induced the swelling of cochlear afferent dendrites and significantly elevated the threshold of the compound action potential (CAP) of the cochlea. CCPA inhibited the KA-induced CAP threshold shift and swelling of the cochlear afferent dendrites. However, CPCA did not affect cochlear excitotoxicity induced by KA. The results suggest that adenosine A1 receptor activation could prevent the excitotoxicity of cochlear afferent dendrites.     

畸胎瘤相关性抗NMDA受体脑炎文献复习--附1例报告

目的：探讨畸胎瘤相关性抗N-甲基-D天冬氨酸(N-methyl-D-aspartate,NMDA)受体脑炎的临床病理特征、发病机制及诊断要点。方法：收集2014年北京市海淀医院病理科卵巢畸胎瘤相关性抗NMDA受体脑炎1例,结合HE形态及免疫组织化学染色,分析畸胎瘤内组织成分,复习国内相关文献,收集其中有全面临床病理资料的畸胎瘤相关性抗NMDA受体脑炎共11例,研究所有12例的临床病理学共性。结果：12例病人均为女性,11例为青年,临床表现均出现精神行为异常及癫痫发作,6例畸胎瘤中含有神经成分,11例脑脊液或血清中检测到抗NMDA受体抗体,脑电图及头颅MRI检测均无特异性,11例病人实施肿瘤切除术并免疫治疗后9人预后良好、1人好转、1人死亡。结论：畸胎瘤相关性抗NMDA受体脑炎是畸胎瘤诱导的自身免疫性脑炎,可能与肿瘤中含有神经成分有关;脑脊液及血清中抗NMDA受体抗体检测阳性可确诊;尽早发现并切除肿瘤有助于病人治愈。     

Eliminating the antilipolytic adenosine A1 receptor does not lead to compensatory changes in the antilipolytic actions of PGE2 and nicotinic acid

Aim: We examined whether compensatory changes after adenosine A₁ receptor knockout [A₁R (−/−)] eliminate the antilipolytic actions mediated by this receptor. Methods: Lipolysis experiments were performed on adipocytes prepared from the wild type A₁R (+/+), A₁R (−/−) and heterozygous mice. Gene expression was assayed with cDNA microarray technique and real‐time PCR; protein expression with immunoblotting. Results: The A₁R was the only adenosine receptor involved in lipolysis. The effects of adenosine deaminase and 2‐chloroadenosine were abolished in A₁R (−/−) mice. The IC₅₀ value of 2‐chloroadenosine doubled from 16.6 to 33.6 nm when half of the A₁Rs were eliminated. Adrenergic α₂ agonists had no effects on lipolysis. Prostaglandin E₂ (PGE₂) inhibited lipolysis with an IC₅₀ value of 5.8 nm (4.7–7.2 nm ) in the A₁R (+/+) mice and 10.6 nm (9.0–12.6 nm ) in the A₁R (−/−) mice. Nicotinic acid inhibited lipolysis with an IC₅₀ value of 0.30 μm (0.19–0.46 μm ) in the A₁R (+/+) mice and 0.24 μm (0.16–0.37 μm ) in the A₁R (−/−) mice. G_iα₁ mRNA was significantly up‐regulated in adipose tissue from A₁R (−/−) mice. However, immunoblotting showed that G_iα1 was not up‐regulated at the protein level. Conclusion: The A₁R mediates the antilipolytic actions of adenosine. Deletion of the A₁R in mice does not result in compensatory increases in G‐protein‐mediated antilipolytic actions of PGE₂ or nicotinic acid.     

Metabotropic glutamate mGlu2 receptor is necessary for the pharmacological and behavioral effects induced by hallucinogenic 5-HT2A receptor agonists

Hallucinogenic drugs, including mescaline, psilocybin and lysergic acid diethylamide (LSD), act at serotonin 5-HT2A receptors (5-HT2ARs). Metabotropic glutamate receptor 2/3 (mGluR2/3) ligands show efficacy in modulating the responses induced by activation of 5-HT2ARs. The formation of a 5-HT2AR-mGluR2 complex suggests a functional interaction that affects the hallucinogen-regulated cellular signaling pathways. Here, we tested the cellular and behavioral effects of hallucinogenic 5-HT2AR agonists in mGluR2 knockout (mGluR2-KO) mice. Mice were intraperitoneally injected with the hallucinogens DOI (2 mg/kg) and LSD (0.24 mg/kg), or vehicle. Head-twitch behavioral response, expression of c-fos, which is induced by all 5-HT2AR agonists, and expression of egr-2, which is hallucinogen-specific, were determined in wild type and mGluR2-KO mice. [(3)H]Ketanserin binding displacement curves by DOI were performed in mouse frontal cortex membrane preparations. Head twitch behavior was abolished in mGluR2-KO mice. The high-affinity binding site of DOI was undetected in mGluR2-KO mice. The hallucinogen DOI induced c-fos in both wild type and mGluR2-KO mice. However, the induction of egr-2 by DOI was eliminated in mGlu2-KO mice. These findings suggest that the 5-HT2AR-mGluR2 complex is necessary for the neuropsychological responses induced by hallucinogens.     

A polymorphism in the growth hormone receptor is associated with height in children with Prader-Willi syndrome

The exon‐3 deletion polymorphism (d3, Database of Genomic Variants ID: Variation_64191) in the growth hormone receptor (GHR) gene is associated with increased growth response to growth hormone (GH) therapy in GH‐deficient patients. However, an association of the GHR genotype with height has not yet been reported in Prader–Willi syndrome (PWS). The aim of this study was to assess the association of GHR alleles with height before starting GH therapy in patients with PWS. Seventy‐four patients with PWS were genotyped and their medical records were retrospectively reviewed (45 males and 29 females, median age 8.7 years). One hundred normal controls, with known final height, were also genotyped. The GH‐exon 3 locus was genotyped using a PCR multiplex assay. The distribution of alleles in the patients with PWS was not different from controls [(fl/fl n = 53 (72%), fl/d3 n = 21 (28%)) in PWS vs. (fl/fl n = 72(72%), fl/d3 n = 26(26%), and d3/d3 n = 2(2%)]. However, patients with PWS carrying a d3 allele had significantly greater height standard deviation scores (SDS) (P = 0.025) and higher insulin‐like growth factor I (IGF‐I) level (P = 0.041), although the age at the start of GH therapy, weight, BMI, and body fat were not different. The d3 allele was associated with height and IGF‐I levels before GH therapy and suggests that even before GH therapy, d3 allele may influence height through GH secretion. © 2011 Wiley Periodicals, Inc.     

Whole gene duplication of SCN2A and SCN3A is associated with neonatal seizures and a normal intellectual development

Duplications at 2q24.3 encompassing the voltage‐gated sodium channel gene cluster are associated with early onset epilepsy. All cases described in the literature have presented in addition with different degrees of intellectual disability, and have involved neighbouring genes in addition to the sodium channel gene cluster. Here, we report eight new cases with overlapping duplications at 2q24 ranging from 0.05 to 7.63 Mb in size. Taken together with the previously reported cases, our study suggests that having an extra copy of SCN2A has an effect on epilepsy pathogenesis, causing benign familial infantile seizures which eventually disappear at the age of 1–2 years. However, the number of copies of SCN2A does not appear to have an effect on cognitive outcome.     

Post-mortem diagnosis of encephalitis in a 75-year-old man associated with human herpesvirus-6 variant A

An HHV-6 variant A infection is described in a 75 year-old man in association with meningoencephalitis identified at autopsy. The patient presented with fever and anorexia, then he developed altered consciousness, motor weakness, progressive lethargy, and coma, and died 21 days after hospital admission. Histopathological examination showed perivascular lymphocytic infiltrates in the central nervous system (CNS). Serum and cerebral spinal fluid (CSF) samples drawn from the patient were tested for viruses by a nested polymerase chain reaction (nPCR). HHV-6 primers A and C [Aubin et al., 1991: J Clin Microb 29: 367-372] and HS6AE and HS6AF from [Dewhurst et al. (1993): J Clin Microb 31: 416-418] disclosed a 750 bp genomic product of HHV-6 in both types of biological samples. Restricted site analysis showed that the HHV-6 DNA amplified belonged to the variant A of the virus. Short sequences of HHV-6 DNA could also be detected in the DNA extracted from formalin-fixed, paraffin-embedded sections of CNS tissues by use of one (GM5 and GM6) of three pairs of HHV-6 primers that were selected. Immunohistochemical examination of brain sections, employing a specific monoclonal antibody directed against the HHV-6 gp 102 protein, detected the viral antigen in neurons and glial cells.     

Sleep and its homeostatic regulation in mice lacking the adenosine A1 receptor

Sleep deprivation (SD) increases extracellular adenosine levels in the basal forebrain, and pharmacological manipulations that increase extracellular adenosine in the same area promote sleep. As pharmacological evidence indicates that the effect is mediated through adenosine A1 receptors (A1R), we expected A1R knockout (KO) mice to have reduced rebound sleep after SD. Male homozygous A1R KO mice, wild-type (WT) mice, and heterozygotes (HET) from a mixed 129/C57BL background were implanted during anesthesia with electrodes for electroencephalography (EEG) and electromyography (EMG). After 1 week of recovery, they were allowed to adapt to recording leads for 2 weeks. EEG and EMG were recorded continuously. All genotypes had a pronounced diurnal sleep/wake rhythm after 2 weeks of adaptation. We then analyzed 24 h of baseline recording, 6 h of SD starting at light onset, and 42 h of recovery recording. Neither rapid eye movement sleep (REM sleep) nor non-REM sleep (NREMS) amounts differed significantly between the groups. SD for 6 h induced a strong NREMS rebound in all three groups. NREMS time and accumulated EEG delta power were equal in WT, HET and KO. Systemic administration of the selective A1R antagonist 8-cyclopentyltheophylline (8-CPT) inhibited sleep for 30 min in WT, whereas saline and 8-CPT both inhibited sleep in KO. We conclude that constitutional lack of adenosine A1R does not prevent the homeostatic regulation of sleep.     

A functional genetic variation of the 5-HTR2A receptor affects age at onset in patients with temporal lobe epilepsy

The 1354C>T polymorphism of the 5-hydroxytryptamine receptor 2A gene (5-HTR2A) was implicated in human memory performance. We investigated the relationship between this polymorphism and cognitive function in patients with temporal lobe epilepsy (TLE). We also evaluated if this polymorphism could influence the phenotype. There were 138 patients with TLE: 25% (34/138) of them found to be cognitively impaired, while the remaining 104 of 138 (75%) were found to be cognitively preserved after a comprehensive neuropsychological evaluation. dHPLC followed by DNA sequencing was used to detect the genetic variation. The distribution of 1354C>T did not differ between these two TLE groups, both in the comparison of genotype distribution (P= 0.177) and allele frequencies (P = 0.065). Nonetheless, patients with the T allele had a significantly earlier age at onset of the disease (P= 0.006). This effect was even stronger in patients with impaired memory (P= 0.00015). A second independent sample of 86 individuals with TLE satisfactorily confirmed the relationship between T allele and age at epilepsy onset. The results of this study have demonstrated that the T variant of 5-HTR2A may influence an earlier age of onset of TLE, especially in those with impaired memory. Nonetheless, this polymorphism has no major impact on memory functions in such TLE patients.     

Ecstasy-induced cell death in cortical neuronal cultures is serotonin 2A-receptor-dependent and potentiated under hyperthermia

Studies on 3,4-methylenedioxymethamphetamine ("ecstasy")-induced neurotoxicity mainly focus on damage of serotonergic terminals. Less attention has been given to neuronal cell death produced by 3,4-methylenedioxymethamphetamine and other amphetamines in areas including the cortex, striatum and thalamus. In the present study we investigated 3,4-methylenedioxymethamphetamine-induced neurotoxicity in neuronal serum free cultures from rat cortex. Since 3,4-methylenedioxymethamphetamine intake induces hyperthermia in both animals and humans, the experiments were performed under normal (36.5 degrees C) and hyperthermic conditions (40 degrees C). Our findings showed a dose-, time- and temperature-dependent apoptotic cell death induced by 3,4-methylenedioxymethamphetamine in cortical neurons. 3,4-Methylenedioxymethamphetamine-induced damage was potentiated under hyperthermia. The neurotoxicity was reduced by the serotonin 2A-receptor antagonists, ketanserin and (2R,4R)-5-[2-[2-[2-(3-methoxyphenyl)ethyl]phenoxy]ethyl]-1-methyl-3-pyrrolidinol hydrochloride, in both normothermic and hyperthermic conditions. (+/-)-2,5-Dimethoxy-4-iodoamphetamine hydrochloride, a model agonist for the serotonin 2A-receptor, also induced a dose- and time-dependent apoptotic cell death. Again, protection was provided by ketanserin and (2R,4R)-5-[2-[2-[2-(3-methoxyphenyl)ethyl]phenoxy]ethyl]-1-methyl-3-pyrrolidinol hydrochloride against (+/-)-2,5-dimethoxy-4-iodoamphetamine hydrochloride-induced neurotoxicity, thereby indicating that the 3,4-methylenedioxymethamphetamine stimulation of the serotonin 2A-receptor leads to neurotoxicity. This study provides for the first time evidence that direct 3,4-methylenedioxymethamphetamine serotonin 2A-receptor stimulation leads to neuronal cortical death. alpha-Phenyl-N-tert-butyl nitrone a free radical scavenger and the nitric oxide synthase inhibitor Nomega-nitro-L-arginine as well as the NMDA-receptor antagonist MK-801 provided protection under normothermia and hyperthermia, thereby suggesting the participation of free radicals in 3,4-methylenedioxymethamphetamine-induced cell death. Since 3,4-methylenedioxymethamphetamine serotonin 2A-receptor agonistic properties lead to neuronal death, clinically available atypical antipsychotic drugs with serotonin 2A-antagonistic properties could be a valuable therapeutic tool against 3,4-methylenedioxymethamphetamine-induced neurodegeneration.     

Distribution of adenosine A2 receptor mRNA in the human brain.

The distribution of the messenger RNA coding for the recently cloned adenosine A₂ receptor was studied in the human brain using in situ hybridization histochemistry. A₂ receptor mRNA is exclusively detected in the medium-sized neurons of the caudate, putamen and accumbens nuclei but not elsewhere in the brain. This highly selective distribution of adenosine A₂ receptor mRNA in human dorsal and ventral striatum, similar to that of adenosine A₂ binding sites reported in rodents, suggests a major role in the basal ganglia physiology.     

Microsatelite GT polymorphism in the toll-like receptor 2 is associated with colorectal cancer

Factors underlying genetic predisposition for development of sporadic colorectal cancer are largely unknown. The fact that this cancer is more common in patients suffering from inflammatory bowel disease raises the question of the relationship between chronic inflammation and cancer. Toll-like receptors 2 (TLR2) and 4 (TLR4) are critical in initiating innate immune response and inflammation toward various bacteria commonly found in the intestine. Recent evidence about the association of polymorphisms in these genes with ulcerative colitis and Crohn's disease, as well as other inflammatory conditions, was the basis for our investigation of their role in sporadic colorectal cancer. We assessed genotype and allele frequencies of TLR2 GT microsatelite polymorphism, TLR2 Arg753Gln, TLR4 Asp299Gly and TLR4 Thr399Ile polymorphisms in 89 colorectal cancer patients and 88 age- and sex-matched controls. The frequency of TLR2 GT microsatelite alleles with 20 and 21 GT repeats was decreased (p = 0.0044 and p = 0.001, respectively), while the frequency of the allele with 31 GT repeats was increased (p = 0.0147) in patients. The mutant allele Asp299Gly of TLR4 gene was slightly more frequent in colorectal cancer patients (p = 0.0269). In conclusion, we report an association of microsatelite GT polymorphisms of TLR2 gene and Asp299Gly polymorphism of the TLR4 gene with sporadic colorectal cancer among Croatians.