Fine mapping by genetic association implicates the chromosome 1q23.3 gene UHMK1, encoding a serine/threonine protein kinase, as a novel schizophrenia susceptibility gene.

BACKGROUND: Linkage studies by us and others have confirmed that chromosome 1q23.3 is a susceptibility locus for schizophrenia. Based on this information, several research groups have published evidence that markers within both the RGS4 and CAPON genes, which are 700 kb apart, independently showed allelic association with schizophrenia. Tests of allelic association with both of these genes in our case control sample were negative. Therefore, we carried out further fine mapping between the RGS4 and CAPON genes. METHODS: Twenty-nine SNP and microsatellite markers in the 1q23.3 region were genotyped in the United Kingdom based sample of 450 cases and 450 supernormal control subjects. RESULTS: We detected positive allelic association after the eighth marker was genotyped and found that three microsatellite markers (p = .011, p = .014, p = .049) and two SNPs (p = .004, p = .043) localized in the 700 kb region between the RGS4 and CAPON genes, within the UHMK1 gene, were associated with schizophrenia. Tests of significance for marker rs10494370 remained significant following Bonferroni correction (alpha = .006) for multiple tests. Tests of haplotypic association were also significant for UHMK1 (p = .009) using empirical permutation tests, which make it unnecessary to further correct for both multiple alleles and multiple markers. CONCLUSIONS: These results provide preliminary evidence that the UHMK1 gene increases susceptibility to schizophrenia. Further confirmation in adequately powered samples is needed. UHMK1 is a serine threonine kinase nuclear protein and is highly expressed in regions of the brain implicated in schizophrenia.     

nNOS磷酸化在大鼠神经病理性疼痛发病中的作用及其机制

目的:探索神经结扎(spinal nerve ligation,SNL)模型大鼠脊髓内神经元型一氧化氮合酶(neuronal nitric oxide synthase,nNOS)的磷酸化是否对神经病理性疼痛具有调节作用,研究nNOS磷酸化在神经病理性疼痛中的作用机制?方法:选用雄性SPF级SD大鼠60只,随机分为4组?假手术组:只暴露脊神经,不结扎;实验组:制作SNL模型,鞘内注射钙依赖性蛋白激酶Ⅱ(phosphorylated calcium/calmodulin dependent kinaseⅡ,p-CaMKⅡ)抑制剂KN93;阴性对照组:制作SNL模型,鞘内注射DMSO;模型组:制作SNL模型,不给药?于术前1 d?术后1~5 d以及鞘内给药后1~4 h测定机械痛阈值?采用Western blot检测腰段脊髓组织p-CaMKⅡ?nNOS与p-nNOS的表达水平,利用免疫共沉淀以及免疫荧光实验检测nNOS与其接头蛋白CAPON是否具有相互作用?结果:SNL可导致大鼠机械疼痛阈值降低(P < 0.01),脊髓组织p-CaMKⅡ的表达增加(P < 0.05),p-nNOS的表达下降(P < 0.05),髓鞘内注射KN93可反转神经结扎所致的上述趋势;nNOS与其接头蛋白CAPON在大鼠体内存在相互作用,nNOS的磷酸化能降低其与CAPON的相互作用强度?结论:nNOS的磷酸化参与了SNL诱导的神经病理性疼痛的维持,p-CaMKⅡ通过对nNOS的磷酸化,降低nNOS与其接头蛋白CAPON在体内的相互作用强度,针对nNOS的磷酸化信号途径的治疗可为神经病理性疼痛的治疗提供新的视野?     

CAPON及其相关分子在大鼠创伤性脑损伤后的表达变化

目的:探讨创伤性脑损伤(TBI)后神经型一氧化氮合酶羧基末端PDZ配体(CAPON)及其相关分子的表达变化及定位。方法:利用实时荧光定量PCR及蛋白免疫印迹技术研究大鼠脑损伤后CAPON及其相关分子Daxras1、nNOS的mRNA及蛋白水平表达变化,利用免疫荧光双标技术检测脑损伤后CAPON分子的细胞定位情况。结果:大鼠TBI后1 d-3 d,CAPON分子mRNA和蛋白表达增加;Dexras1及nNOS的表达变化趋势与CAPON的相一致。在损伤区CAPON主要表达于NeuN阳性的神经元;在损伤周边皮质中,CAPON与星型胶质细胞的标记物GFAP有少量共定位;此外,CAPON在OX-42阳性的小胶质细胞中也有少量的表达。结论:创伤性脑损伤后,CAPON及其相关分子(Daxras1、nNOS)可被诱导表达,损伤神经细胞内的CAPON及其相关分子可能参与了TBI的病理进程。     

Involvement of CAPON and Nitric Oxide Synthases in Rat Muscle Regeneration After Peripheral Nerve Injury

Carboxy-terminal PDZ ligand of nNOS (CAPON) protein, as an adaptor, binds to nNOS via the PDZ domain helping regulate neuronal nitric oxide synthase (nNOS) activity at post-synaptic sites in neurons (Jaffrey et al., Neuron, 20, 115–124, 1998). Recently, it has been reported that CAPON is present in mouse muscle and may be involved in mouse muscle growth, injury, and repair possibly by regulating the stability, activity, or position of nNOS (Segalat et al., Experimental Cell Research, 302, 170–179, 2005). The present study was to explore the expression patterns and roles of CAPON as well as NOS in rat muscle regeneration after nerve injury. Normal Sprague–Dawley rats were subjected to right sciatic nerve crush injury. Walking track analysis, real time polymerase chain reaction, Western blotting, in situ hybridization, immunocytochemistry, and co-immunoprecipitation techniques were used. It revealed that CAPON mRNA increased, which peaked on days 1 and 28, whereas nNOS mRNA underwent a downregulation in the ipsilateral gastrocnemius muscles after sciatic nerve injury. Their proteins approximately paralleled the mRNA expression. CAPON and nNOS were identified in the activated satellite cells or myotubes and their in vivo interaction was verified. However, eNOS and iNOS proteins suffered an upregulation and were detected in activated satellite cells or myotubes. These data suggest that CAPON and all these three isoforms of NOS might be involved in muscle regeneration after nerve injury. Further study is necessary for a better understanding of the potential functional link between CAPON, NOS, and muscle regeneration, with possible application to therapy for skeletal muscle repair from nerve injury. M. Chen and C. Cheng contribute equally to this work.     

nNOS-mediated protein-protein interactions:promising targets for treating neurological and neuropsychiatric disorders

Neurological and neuropsychiatric disorders are one of the leading causes of disability worldwide and affect the health of billions of people.Nitric oxide(NO),a free gas with multitudinous bioactivities,is mainly produced from the oxidation of L-arginine by neuronal nitric oxide synthase(nNOS)in the brain.Inhibiting nNOS benefits a variety of neurological and neuropsychiatric disorders,including stroke,depression and anxiety disorders,posttraumatic stress disorder,Parkinson’s disease,Alzheimer’s disease,chronic pain,and drug addiction.Due to critical roles of nNOS in learning and memory and synaptic plasticity,direct inhibition of nNOS may cause severe side effects.Importantly,interactions of several proteins,including post-synaptic density 95(PSD-95),carboxyterminal PDZ ligand of nNOS(CAPON)and serotonin transporter(SERT),with the PSD/Disc-large/ZO-1 homologous(PDZ)domain of nNOS have been demonstrated to influence the subcellular distribution and activity of the enzyme in the brain.Therefore,it will be a preferable means to interfere with nNOS-mediated proteinprotein interactions(PPIs),which do not lead to undesirable effects.Herein,we summarize the current literatures on nNOS-mediated PPIs involved in neurological and neuropsychiatric disorders,and the discovery of drugs targeting the PPIs,which is expected to provide potential targets for developing novel drugs and new strategy for the treatment of neurological and neuropsychiatric disorders.     

Developmental expression of CAPON and Dexras1 in spinal cord of rats

To study the expression of the carboxy-terminal PSD-95/DLG/ZO-1 ligand of nNOS (CAPON) and Dexras1 mRNA during development in the spinal cord of rats, real-time polymerase chain reaction (Real-time PCR), as a quantitative method, was used to study the developmental expression of CAPOn and Dexras1 mRNA level in the spinal cord. The spatial expression of CAPON and Dexras1 mRNA was examined by a combination of in situ hybridization (ISH) and immunofluorescence. During the development of the spinal cord, CAPON mRNA was expressed in low levels from embryo day 14 to day 18. At postnatal day 1, it reached the peak and was expressed in the part which will become the dorsal horn when mature. It then decreased gradually until postnatal week 12, when it presented in the ventral horn. At embryo day 14, Dexras1 mRNA was expressed at low levels, increased during embryo day 16 to day 18 and peaked at postnatal day 1. Spatiotemporal expression of Dexras1 mRNA was similar to CAPOn as confirmed by correlation analysis and colocalization. CAPOn and neuronal nitric oxide synthase (nNOS) was expressed within the same cells of the dorsal horn at postnatal day 1 but had different subcellular localizations. Co-expression of CAPOn and Dexras1 mRNA in myeloid tissue during development process of rat indicates that the adaptor protein, CAPON may play a probable role in differentiation of neurons, synaptic plasticity and synaptogenesis by regulating nNOS to activate Dexras1. __________ Translated from Chinese Journal of Neuroanatomy, 2007, 23(4): 349–354 [译自: 神经解剖学杂志]     

Family-based association studies of CAPON and schizophrenia in the Chinese Han population

Although there is evidence pointing to CAPON as a susceptible gene for schizophrenia, the results of independent association studies have so far been inconsistent. A recent case-control study by Zheng et al. supported CAPON as a susceptible site for the disease in the Chinese Han population. In their study both the single polymorphism (rs348624) and individual haplotypes showed significant association with schizophrenia. Our study further investigates this relationship this time using a family-based association. We selected 5 SNPs including rs348624 and performed a Transmission Disequilibrium Test (TDT) in 319 Chinese Han trios. Our results identified no single marker nor haplotype associated with schizophrenia, which did not suggest that CAPON was a susceptible site in the Chinese Han population, or it appeared unlikely that the CAPON played a major role in the aetiology of schizophrenia. Since there is consistent evidence pointing to 1q21-22 as a positional candidate region for schizophrenia, we suggest that further research should focus on other genes located in this region.     

Failure to confirm allelic association between markers at the CAPON gene locus and schizophrenia in a British sample.

BACKGROUND: Linkage studies have confirmed that chromosome 1q23.3 is a susceptibility locus for schizophrenia. It was then claimed that markers at the carboxyl-terminal PDZ ligand of neuronal nitric oxide synthase (CAPON) gene showed allelic association with schizophrenia in Canadian families. A second Chinese study found a base pair polymorphism at the CAPON gene also associated with schizophrenia. METHODS: We attempted replication using eight markers from the Canadian study in a UK based sample of 450 cases and 450 supernormal controls. RESULTS: We found no evidence for allelic or haplotypic association with schizophrenia for any of the markers found to be associated in the Canadian sample. CONCLUSIONS: The negative results might reflect genetic heterogeneity between the Canadian, Chinese and UK samples or be due to methodological problems. The present finding weakens the evidence that mutations or variation in the CAPON gene are causing genetic susceptibility to schizophrenia in European populations.     

Expression of CAPON after Spinal Cord Injury in Rats

The adaptor protein, carboxy-terminal PDZ ligand of nNOS (CAPON), regulates the distribution of neuronal nitric oxide synthase (nNOS) that increased after spinal cord injury (SCI) and produces the key signaling molecule nitric oxide (NO). But little is known about the role of CAPON in the pathological process of SCI. The main objective of the present study was to investigate expression of CAPON and nNOS in a spinal cord contusion model in adult rats. Real time-polymerase chain reaction (PCR) and Western blot analysis revealed that mRNA and protein for CAPON increased at 2 h after SCI and reached the peak at 8 h, gradually recovered to the baseline level at 14 days. The expression of nNOS mRNA and protein was similar to that of CAPON. During the peak expression, CAPON mRNA was found in the ventral horn, mediate zone, dorsal horn, and white matter by in situ hybridization. Immunofluorescence showed that CAPON was colocalized with nNOS in neurons, oligodendrocytes, and some astrocytes of spinal cord tissues within 5 mm from the epicenter. Interaction between CAPON and nNOS was also detected by co-immunoprecipitation. Thus, the transient expression of high levels of CAPON may provide new insight into the secondary response after SCI. Chun Cheng and Xin Li contributed equally to this work.