Deficiency of the purine metabolic gene HPRT dysregulates microRNA-17 family cluster and guanine-based cellular functions: a role for EPAC in Lesch-Nyhan syndrome
Deficiency of the purine metabolic gene HPRT dysregulates microRNA-17 family cluster and guanine-based cellular functions: a role for EPAC in Lesch-Nyhan syndrome
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DOI：
10.1093/hmg/ddt298
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发表时间：
2013-11-15
影响因子：
3.5
通讯作者：
Hrustanovic, Gorjan
中科院分区：
文献类型：
--
作者：
Guibinga, Ghiabe-Henri;Murray, Fiona;Hrustanovic, Gorjan
莱施-尼汉综合征（LNS）是一种由编码嘌呤代谢酶次黄嘌呤-鸟嘌呤磷酸核糖基转移酶（HPRT）的基因突变引起的神经发育障碍。一系列的运动，认知和神经行为异常的特点，这种疾病的表型，这仍然是知之甚少。这种综合征的临床表现被认为是神经发育途径缺陷导致脑功能紊乱的后果。我们已经使用microRNA阵列和基因本体分析来评估分化HPRT缺陷的人神经元样细胞系的基因表达。我们着手确定与嘌呤为基础的细胞功能有关的失调基因。我们的方法是基于这样的前提，即HPRT缺陷会显著影响嘌呤基分子复合物的表达和功能，如鸟嘌呤核苷酸交换因子（GEFs）和小GTP酶。我们发现，来自miR-17家族簇的几种microRNA和编码GEF的基因在HPRT缺陷中失调。最值得注意的是，我们的数据显示，由cAMP激活的交换蛋白（EPAC）的表达在HPRT缺陷的人神经元样细胞系和LNS患者的成纤维细胞中是钝化的，并且在HPRT敲除小鼠的皮质、纹状体和中脑中是改变的。我们还显示了一个显着的损伤，在HPRT缺陷的细胞中的小GTP酶RAP 1的激活，以及细胞骨架动力学的差异，导致HPRT缺陷的神经元样细胞系相对于控制的运动性增加。我们认为HPRT缺乏时EPAC/RAP 1信号传导和细胞迁移的改变对于可能导致LNS神经功能障碍的神经发育事件至关重要。
Lesch-Nyhan syndrome (LNS) is a neurodevelopmental disorder caused by mutations in the gene encoding the purine metabolic enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT). A series of motor, cognitive and neurobehavioral anomalies characterize this disease phenotype, which is still poorly understood. The clinical manifestations of this syndrome are believed to be the consequences of deficiencies in neurodevelopmental pathways that lead to disordered brain function. We have used microRNA array and gene ontology analysis to evaluate the gene expression of differentiating HPRT-deficient human neuron-like cell lines. We set out to identify dysregulated genes implicated in purine-based cellular functions. Our approach was based on the premise that HPRT deficiency affects preeminently the expression and the function of purine-based molecular complexes, such as guanine nucleotide exchange factors (GEFs) and small GTPases. We found that several microRNAs from the miR-17 family cluster and genes encoding GEF are dysregulated in HPRT deficiency. Most notably, our data show that the expression of the exchange protein activated by cAMP (EPAC) is blunted in HPRT-deficient human neuron-like cell lines and fibroblast cells from LNS patients, and is altered in the cortex, striatum and midbrain of HPRT knockout mouse. We also show a marked impairment in the activation of small GTPase RAP1 in the HPRT-deficient cells, as well as differences in cytoskeleton dynamics that lead to increased motility for HPRT-deficient neuron-like cell lines relative to control. We propose that the alterations in EPAC/RAP1 signaling and cell migration in HPRT deficiency are crucial for neuro-developmental events that may contribute to the neurological dysfunctions in LNS.