Neuregulin-1 (NRG-1) mRNA and protein in the adult human brain

Neuregulin-1 (NRG-1) plays important roles in the development and plasticity of the brain, and it has recently been identified as a susceptibility gene for schizophrenia. Though there are rodent data, little is known about its distribution in the human brain. The aim of this study was to ascertain the localization of NRG-1 and its mRNA in multiple regions of the normal adult human brain. We investigated NRG-1 mRNA in 11 subjects using in situ hybridization and northern analysis, and NRG-1 protein in six subjects using immunohistochemistry and Western blotting. NRG-1 mRNA was present as bands of approximately 2, 3 and 6 kb. It was clearly detected in the prefrontal cortex (middle laminae), hippocampal formation (except CA1), cerebellum, oculomotor nucleus, superior colliculus, red nucleus and substantia nigra pars compacta. At the cellular level, NRG1 mRNA was abundant in hippocampal and cortical pyramidal neurons and some interneurons, and in cerebellar Purkinje cells and Golgi cells. NRG-1 protein was detected as bands of approximately 140, 110, 95 and 60 kD. Immunohistochemistry revealed NRG-1 in many cell populations, consistent with the mRNA data, being prominent in pyramidal neurons, Purkinje cells, several brainstem nuclei, and white matter neurons. Moderate NRG-1 immunoreactivity was also observed in cerebellar and dentate gyrus granule cells, and some glia. Within neurons, NRG-1 staining was primarily somatodendritic; in the cell body staining was granular, with clustering close to the plasma and nuclear membranes. There was also labeling of some fiber tracts, and local areas of neuropil (e.g. in the dentate nucleus) suggestive of a pre-synaptic location of NRG-1. The data show a widespread expression of NRG-1 in the adult human brain, including, but not limited to, brain areas and cell populations implicated in schizophrenia. Using these normative data, future studies can ascertain whether the role of NRG-1 in the disease is mediated, or accompanied, via alterations in its expression.     

Dysbindin-1 is a synaptic and microtubular protein that binds brain snapin

Variations in the gene encoding the novel protein dysbindin-1 (DTNBP1) are among the most commonly reported genetic variations associated with schizophrenia. Recent studies show that those variations are also associated with cognitive functioning in carriers with and without psychiatric diagnoses, suggesting a general role for dysbindin-1 in cognition. Such a role could stem from the protein's known ability to affect neuronal glutamate release. How dysbindin-1 might affect glutamate release nevertheless remains unknown without the discovery of the protein's neuronal binding partners and its subcellular locus of action. We demonstrate here that snapin is a binding partner of dysbindin-1 in vitro and in the brain. Tissue fractionation of whole mouse brains and human hippocampal formations revealed that both dysbindin-1 and snapin are concentrated in tissue enriched in synaptic vesicle membranes and less commonly in postsynaptic densities. It is not detected in presynaptic tissue fractions lacking synaptic vesicles. Consistent with that finding, immunoelectron microscopy showed that dysbindin-1 is located in (i) synaptic vesicles of axospinous terminals in the dentate gyrus inner molecular layer and CA1 stratum radiatum and in (ii) postsynaptic densities and microtubules of dentate hilus neurons and CA1 pyramidal cells. The labeled synapses are often asymmetric with thick postsynaptic densities suggestive of glutamatergic synapses, which are likely to be derived from dentate mossy cells and CA3 pyramidal cells. The function of dysbindin-1 in presynaptic, postsynaptic and microtubule locations may all be related to known functions of snapin.     

Expression of DISC1 binding partners is reduced in schizophrenia and associated with DISC1 SNPs

DISC1 has been identified as a schizophrenia susceptibility gene based on linkage and SNP association studies and clinical data suggesting that risk SNPs impact on hippocampal structure and function. In cell and animal models, C-terminus-truncated DISC1 disrupts intracellular transport, neural architecture and migration, perhaps because it fails to interact with binding partners involved in neuronal differentiation such as fasciculation and elongation protein zeta-1 (FEZ1), platelet-activating factor acetylhydrolase, isoform Ib, PAFAH1B1 or lissencephaly 1 protein (LIS1) and nuclear distribution element-like (NUDEL). We hypothesized that altered expression of DISC1 and/or its molecular partners may underlie its pathogenic role in schizophrenia and explain its genetic association. We examined the expression of DISC1 and these selected binding partners as well as reelin, a protein in a related signaling pathway, in the hippocampus and dorsolateral prefrontal cortex of postmortem human brain patients with schizophrenia and controls. We found no difference in the expression of DISC1 or reelin mRNA in schizophrenia and no association with previously identified risk DISC1 SNPs. However, the expression of NUDEL, FEZ1 and LIS1 was each significantly reduced in the brain tissue from patients with schizophrenia and expression of each showed association with high-risk DISC1 polymorphisms. Although, many other DISC1 binding partners still need to be investigated, these data implicate genetically linked abnormalities in the DISC1 molecular pathway in the pathophysiology of schizophrenia.     

小鼠精子发生过程中dysbindin-1的表达

目的 探讨精子发生过程中dysbindin-1的表达及dysbindin-1对精子顶体形态的影响。 方法 取生后7d、14d、21d、28d、35d和3月龄的雄性小鼠各3只,用免疫印迹法检测睾丸组织dysbindin-1的表达;以dysbindin-1缺失突变的sdy小鼠为研究对象,收集附睾尾部精子,一部分制备精子涂片,HE染色显示精子形态,用异硫氰酸荧光素-豌豆凝集素（FITC-PSA）和抗精子蛋白56（sp56）单克隆抗体进行荧光染色显示顶体的结构;另一部分采用免疫印迹法检测精子中dysbindin-1的表达。 结果 不同发育阶段小鼠睾丸组织及精子中均只有dysbindin-1A,无dysbindin-1C的表达;sdy小鼠的精子及顶体的形态未见明显异常。 结论 Dysbindin-1A表达于小鼠精子发生的不同时期,dysbindin-1A对精子形态维持不起关键作用。     

Neuregulin-1β对压力超负荷心肌肥大大鼠治疗作用及机制的研究

 目的：研究神经调节蛋白 1β（NRG-1β）对压力超负荷所致大鼠心肌肥大的治疗作用并探讨其机制。方法：Wistar雄性大鼠采用腹主动脉缩窄的方法复制心肌肥大模型。术后8周,将模型动物随机分成模型（model）组、NRG-1β治疗组（尾静脉注射NRG-1β,10 μg·kg-1·d-1）和NRG-1β+赫赛汀(Herceptin, HERCE)治疗组（尾静脉注射NRG-1β的同时给予注射HERCE 10 μg·kg-1·d-1）。假手术（sham）组除不以银夹缩窄腹主动脉外,其余操作同腹主动脉缩窄组。7　d后分别采用心动超声、血流动力学评价心功能;Masson染色观察心肌组织的超微结构;放射免疫法检测心肌组织中血管紧张素II（Ang II）,酶联免疫吸附法测定心肌组织中肿瘤坏死因子 α（TNF-α）的变化;RT-PCR法检测心肌中bcl-2和bax mRMA表达的改变。结果：（1）心动超声显示,和模型组比较,NRG-1β组左室射血分数(LVEF)及短轴缩短率(LVFS)升高,左室收缩末内径(LVESD)及舒张末内径(LVEDD)减小（P<0.01）。（2）血流动力学检测显示,NRG-1β治疗组左室收缩末压(LVESP)和左室内压最大上升和下降速率(±dp/dtmax)均明显高于模型组（P<0.01）;左室舒张末压(LVEDP)低于模型组（P<0.01）。（3）与模型组比较,NRG-1β组心肌胶原容积分数（CVF）下降,心肌中Ang II和TNF-α明显减少,bcl-2 mRNA表达显著升高,而bax mRNA表达下降（P<0.01）。（4）NRG-1β+ HERCE治疗组与模型组相比各项指标无明显改变（P>0.05）。结论：NRG-1可以减少压力超负荷大鼠心肌Ang II和TNF-α的生成,从而减轻Ang II和TNF-α介导的心肌间质重构; NRG-1可通过上调bcl-2 mRNA表达、下调bax mRNA表达,抑制心肌细胞的凋亡,改善压力超负荷大鼠的心功能,进而在心肌肥大的过程中发挥作用。     

低氧刺激诱导体外培养的大鼠脑皮质星形胶质细胞内neuregulin-1表达上调

Neuregulin-1(NRG-1)是神经胶质及神经元产生的细胞间信号转导蛋白。该蛋白通过与ErbB受体结合,对神经系统的正常发育、成熟发挥重要作用,也在缺血性脑损伤时起神经保护作用。为探讨体外培养的星形胶质细胞受缺氧刺激后NRG-1的表达特点,本实验利用体外培养的大鼠脑皮质星形胶质细胞,采用免疫组织化学和Westernblot方法,比较了正常培养和低氧复氧条件下星形胶质细胞中NRG1的表达。结果显示:正常培养的星形胶质细胞中有NRG-1的表达,但含量不高;低氧复氧培养后星形胶质细胞NRG1的表达量随着复氧时间的延长缓慢增加,至复氧8h,其表达量陡然升高,达到峰值后又逐渐降低,甚至降至正常水平以下。本研究表明,在低氧缺血性脑损伤后,星形胶质细胞反应性大量产生NRG1的时间相对滞后。由此提示,低氧缺血性脑损伤后,立即使用外源性神经保护剂为宜。     

Brain isoforms of creatine kinase in health and mental diseases: Alzheimer's disease and schizophrenia

The paper analyzes the authors' own findings and the data available in the literature on the intensity, site, and possible causes of impairment of the creatine-creatine phosphate system of brain energy metabolism in mental diseases, such as Alzheimer's disease (AD) and schizophrenia. Examining the level of cytosolic BB creatine kinase in postmortem AD and schizophrenic's brain structures showed a significant decrease in BB creatine kinase as compared with the similar control brain structures. There was the maximum decline in AD cases. It was considerable as compared with both the control and schizophrenic groups (p < 0.01). The decrement was revealed by various techniques, including the determination of activity, immunological responsiveness and the analysis of two-dimensional protein maps. Immunocytochemical investigation indicated a decrease in responses to BB creatine kinase, mainly in astrocytes. The reduction in cytosolic BB creatine kinase levels is not a result of age, postmortem delay, or psychotic therapy. The causes of lower BB creatine kinase levels in the cell cytosol of the postmortem brain in mental pathology are discussed. The decrement in cytosolic BB creatine kinase in AD and schizophrenia occurs not only in the brain, but also in the peripheral tissues which contain BB creatine kinase. In all cases, it is greater in AD than in schizophrenia. Using immunosorbents with monoclonal antibodies to M-creatine kinase and to B-creatine kinase subunits makes it possible detect BB-creatine kinase in the extracts of human peripheral lymphocytes and platelets. A study of whether there is a relationship between the clinical data of mental patients and the level of BB creatine kinase in their blood elements is assumed to be useful in evaluating BB creatine kinase as a prognostic/diagnostic marker of mental diseases.     

Genetic variation in DTNBP1 influences general cognitive ability

Human intelligence is a trait that is known to be significantly influenced by genetic factors, and recent linkage data provide positional evidence to suggest that a region on chromosome 6p, previously associated with schizophrenia, may be linked to variation in intelligence. The gene for dysbindin-1 (DTNBP1) is located at 6p and has also been implicated in schizophrenia, a neuropsychiatric disorder characterized by cognitive dysfunction. We report an association between DTNBP1 genotype and general cognitive ability (g) in two independent cohorts, including 213 patients with schizophrenia or schizo-affective disorder and 126 healthy volunteers. These data suggest that DTNBP1 genetic variation influences human intelligence.     

Dyslexia associated functional variants in Europeans are not associated with dyslexia in Chinese

Genome‐wide association studies (GWAS) of developmental dyslexia (DD) often used European samples and identified only a handful associations with moderate or weak effects. This study aims to identify DD functional variants by integrating the GWAS associations with tissue‐specific functional data and test the variants in a Chinese DD study cohort named READ. We colocalized associations from nine DD related GWAS with expression quantitative trait loci (eQTL) derived from brain tissues and identified two eSNPs rs349045 and rs201605. Both eSNPs had supportive evidence of chromatin interactions observed in human hippocampus tissues and their respective target genes ZNF45 and DNAH9 both had lower expression in brain tissues in schizophrenia patients than controls. In contrast, an eSNP rs4234898 previously identified based on eQTL from the lymphoblastic cell lines of dyslexic children had no chromatin interaction with its target gene SLC2A3 in hippocampus tissues and SLC2A3 expressed higher in the schizophrenia patients than controls. We genotyped the three eSNPs in the READ cohort of 372 cases and 354 controls and discovered only weak associations in rs201605 and rs4234898 with three DD symptoms (p < .05). The lack of associations could be due to low power in READ but could also implicate different etiology of DD in Chinese.     

Phenotypic spectrum of GNAO1 variants: epileptic encephalopathy to involuntary movements with severe developmental delay

De novo GNAO1 variants have been found in four patients including three patients with Ohtahara syndrome and one patient with childhood epilepsy. In addition, two patients showed involuntary movements, suggesting that GNAO1 variants can cause various neurological phenotypes. Here we report an additional four patients with de novo missense GNAO1 variants, one of which was identical to that of the previously reported. All the three novel variants were predicted to impair Gαo function by structural evaluation. Two patients showed early-onset epileptic encephalopathy, presenting with migrating or multifocal partial seizures in their clinical course, but the remaining two patients showed no or a few seizures. All the four patients showed severe intellectual disability, motor developmental delay, and involuntary movements. Progressive cerebral atrophy and thin corpus callosum were common features in brain images. Our study demonstrated that GNAO1 variants can cause involuntary movements and severe developmental delay with/without seizures, including various types of early-onset epileptic encephalopathy.     

A cross-laboratory comparison of expression profiling data from normal human postmortem brain

Expression profiling of post-mortem human brain tissue has been widely used to study molecular changes associated with neuropsychiatric diseases as well as normal processes such as aging. Changes in expression associated with factors such as age, gender or postmortem interval are often more pronounced than changes associated with disease. Therefore in addition to being of interest in their own right, careful consideration of these effects are important in the interpretation of disease studies. We performed a large meta-analysis of genome-wide expression studies of normal human cortex to more fully catalogue the effects of age, gender, postmortem interval and brain pH, yielding a “meta-signature” of gene expression changes for each factor. We validated our results by showing a significant overlap with independent gene lists extracted from the literature. Importantly, meta-analysis identifies genes which are not significant in any individual study. Finally, we show that many schizophrenia candidate genes appear in the meta-signatures, reinforcing the idea that studies must be carefully controlled for interactions between these factors and disease. In addition to the inherent value of the meta-signatures, our results provide critical information for future studies of disease effects in the human brain.     

Detailed DARPP-32 expression profiles in postmortem brains from patients with schizophrenia: an immunohistochemical study

The prevalence of dopamine and cAMP-regulated phosphoprotein 32kD (DARPP-32) is associated with the pathogenesis of schizophrenia. To date, the findings on DARPP-32 cellular expression and distribution in postmortem brains from patients with schizophrenia have been inconsistent. To clarify the detailed cellular expression of DARPP-32 in patients with schizophrenia, we immunohistochemically stained sections from postmortem brains using specific antibodies. We measured the density of immunopositive cells in various brain regions including the prefrontal cortex and compared the data from nine schizophrenia subjects with those of nine age- and sex-matched control subjects. The density of DARPP-32-immunoreactive (IR) neurons was significantly lower in layers II-V of the dorsolateral prefrontal cortex (DLPFC) from subjects with schizophrenia. In contrast, there were no marked differences in DARPP-32 expression in other brain regions. In addition, the density of threonine (Thr34)-phosphorylated DARPP-32-IR neurons was significantly higher in layer V of DLPFC from subjects with schizophrenia. These results suggest that the decrease in DARPP-32 in schizophrenia was more marked in neurons of DLPFC than in other cells or other brain regions, and that this decrease might be partly compensated for by an increase in expression of Thr34-phosphorylated DARPP-32 in DLPFC.     

Dysregulation of miRNA 181b in the temporal cortex in schizophrenia

Analysis of global microRNA (miRNA) expression in postmortem cortical grey matter from the superior temporal gyrus, revealed significant up-regulation of miR-181b expression in schizophrenia. This finding was supported by quantitative real-time RT-PCR analysis of miRNA expression in a cohort of 21 matched pairs of schizophrenia and non-psychiatric controls. The implications of this finding are substantial, as this miRNA is predicted to regulate many target genes with potential significance to the development of schizophrenia. They include the calcium sensor gene visinin-like 1 (VSNL1) and the ionotropic AMPA glutamate receptor subunit (GRIA2), which were found to be down-regulated in the same cortical tissue from the schizophrenia group. Both of these genes were also suppressed in miR-181b transfected cells and shown to contain functional miR-181b miRNA recognition elements by reporter gene assay. This study suggests altered miRNA levels could be a significant factor in the dysregulation of cortical gene expression in schizophrenia.     

Neuregulin-1在糖尿病大鼠心肌组织中的表达变化

目的: 探讨neuregulin-1(NRG-1)在糖尿病大鼠心肌组织中的表达。方法: 45只雄性SD大鼠随机分为4周、8周和12周糖尿病组(4th、8th 和12th DM组),4周、8周和12周对照组(4th 、8th 和12th C组)。腹腔注射链脲佐菌素诱导糖尿病模型。在诱导糖尿病后第4、8和12周用超声诊断仪评估大鼠心功能,计算心肌胶原容积分数(CVF),免疫组化观察NRG-1在心肌的表达部位,RT-PCR和Western blotting检测NRG-1 mRNA及蛋白的表达水平。结果: 4th DM组大鼠心功能指标、心肌CVF、NRG-1 mRNA及蛋白的表达与4thC组相比,差异无统计学意义(P>0.05);与8th C组相比,8th DM组左室收缩末内径(LVESD)和心肌CVF均增高,但左室短轴缩短率(LVFS)、左室射血分数(LVEF)、心肌NRG-1 mRNA及蛋白的表达仍未见明显改变(P>0.05)。与12th C组比较,12th DM组LVESD和心肌CVF均显著增高,而LVFS和LVEF显著降低(均P<0.01)。12th DM组心肌NRG-1 mRNA及蛋白的表达较同期对照组显著下调(0.073±0.008 vs 0.156±0.010,0.171±0.054 vs 0.324±0.039,均P<0.01)。结论: NRG-1在糖尿病大鼠心肌组织中的表达显著下调,这可能参与了糖尿病心肌病的发生和发展。     

A decrease in interleukin-1 receptor antagonist expression in the prefrontal cortex of schizophrenic patients

Interleukin-1 (IL-1) mediates psychological stress responses by regulating monoamine metabolism and secretion of corticotropin-releasing factor, and is therefore, implicated in various psychiatric diseases. To evaluate the contribution of IL-1 signaling to the brain pathology of schizophrenia, we measured protein and/or mRNA levels for IL-1beta and endogenous IL-1 receptor antagonist (IL-1RA) in the postmortem brain tissues of prefrontal and parietal cortex, putamen, and hypothalamus. Both protein and mRNA levels of IL-1RA were specifically decreased in the prefrontal cortex of schizophrenic patients, whereas IL-1beta levels were not significantly altered in all the regions examined. The IL-1RA decrease was not correlated with the dose of antipsychotics given to patients. There was no influence of this illness on protein levels for IL-1 receptor type 1 in the prefrontal cortex, either. In contrast, IL-1RA serum levels were increased in schizophrenic patients, especially in drug-free patients, as reported previously. These findings suggest that chronic schizophrenia down-regulates IL-1RA production the prefrontal cortex, irrespective of its impact on the periphery. IL-1RA reduction might reflect an immunopathologic trait of the prefrontal region in schizophrenic patients.