下丘脑转录组分析揭示GK大鼠致糖尿病过程中的基因调控网络

发布时间：2018-10-16 13:32

【摘要】：2型糖尿病(type 2 diabetes,T2D)是一种具有高血糖症、外周靶标器官胰岛素抵抗以及胰岛β细胞功能紊乱或者胰岛素释放不足等特征的流行性疾病。在2015年的国际糖尿病联盟报告中指出,糖尿病困扰了全球超过4.15亿的人口,其中大约1/4的糖尿病病例发生在中国。相对于欧美地区的人群,在中国以至东亚地区人群的糖尿病患者在很大程度上具有相对较低的BMI值(身体质量指数)。2015年因糖尿病及相关疾病的致死人数已达500万,因此,找到一种合适的T2D动物模型研究非肥胖T2D机制非常有必要。GK(Goto Kakizaki)大鼠是一种自发非肥胖的T2D动物模型,其除了具有相对较低的BMI以外,还伴随有高血糖症、β细胞缺陷以及外周组织胰岛素抵抗等特征。下丘脑控制着机体的摄食行为并且在保持全身能量平衡的过程中起到关键作用。下丘脑能够感受外周组织释放的激素以及体液循环中的营养物质,从而调控着外周组织的能量消耗度,并控制机体的摄食行为。下丘脑的功能障碍可导致一系列的代谢紊乱症状,在前期肥胖与食物诱导的T2D研究报道中显示,下丘脑可能在T2D的发生和发展过程中中起着关键的作用。为了研究非肥胖的GK大鼠下丘脑在糖尿病发病过程中的分子机制,本研究对第4、8和12周龄的GK大鼠下丘脑进行了转录组测序(RNA-seq),通过GK大鼠下丘脑4-12周的转录组差异表达基因分析、GK大鼠种群的特异性突变和表达谱与突变整合的模块分析,得到主要结果如下:(1)在Wistar和GK大鼠中,大约有13600个基因在下丘脑中被检测到具有表达,其中1119、1381和1702个GK大鼠基因分别在第4、8和12周中具有显著差异。基因的差异表达分析表明了GK大鼠下丘脑的黑皮质素系统具有功能紊乱和下丘脑葡萄糖感受途径受损的现象,这影响了GK大鼠的摄食行为并可能对GK大鼠的能量平衡产生影响。(2)在Wistar和GK大鼠的基因中分别检测到22783和25582个突变(相对于参考的挪威大鼠),其中包含了5831个Wistar大鼠特异性突变和8630个GK大鼠特异性突变。在这些突变基因中,有767个Wistar大鼠特异性基因和1316个GK大鼠特异性基因。基因突变的结果显示GK大鼠的基因突变数目比对照组的Wistar大鼠的要显著增多,表明了GK大鼠在具有选择性的不断重复自交过程中有很多新的突变被固定并遗传了下来。(3)通过蛋白质相互作用网络和下丘脑转录组共表达网络,结合Wistar和GK大鼠的基因突变整合了一系列的基因网络模块。这些模块的基因之间具有高共表达和相互作用的关系,而且富集了GK大鼠的突变基因,为揭示GK大鼠下丘脑的调控网络提供了重要依据。在这些模块中的GK大鼠特异性基因,例如Bad,Map2k2,Adcy3,Adcy2和Gstm6等基因参与了多条重要的信号通路调控,可能在GK大鼠的下丘脑调控中扮演着重要角色。本研究通过高通量转录组测序全面揭示了GK大鼠下丘脑的基因表达规律和基因变异情况,为揭示T2D发病进程中的分子机制提供了新的理论依据,同时也为中枢神经性系统下丘脑在T2D发病进程中的作用机制提供了新的证据。本研究的主要创新点有:(1)利用GK大鼠糖尿病发病进程中下丘脑的转录组表达规律揭示了GK大鼠下丘脑葡萄糖感受途径受损的机制以及黑皮质素系统紊乱与GK大鼠摄食过多的关系,阐释了GK大鼠下丘脑在能量平衡中的调控对T2D形成的影响。(2)整合GK大鼠糖尿病发病进程中下丘脑的转录组表达与GK大鼠基因突变,通过基因网络模块分析,揭示GK大鼠特异性基因对下丘脑调控作用的影响。
[Abstract]:Type 2 diabetes mellitus (T2D) is an epidemic disease characterized by hyperglycemia, peripheral target organ insulin resistance, pancreatic islet cell function disorder or insufficient insulin release. Diabetes has plagued more than 41.5 billion people worldwide, according to the 2015 International Diabetes Federation report, with about 1/ 4 of the diabetes cases occurring in China. Diabetes patients in China and East Asia have a relatively low BMI (body mass index) to a large extent relative to populations in Europe and the East Asian region. The number of deaths caused by diabetes and related diseases in 2015 has reached 5 million, and therefore, It is necessary to find a suitable T2D animal model to study the non-obese T2D mechanism. GK (Goto Kakizaki) rat is a spontaneous, non-obese, T2D animal model, in addition to having a relatively low BMI, accompanied by features such as hyperglycemia, impaired cellular defects, and peripheral tissue insulin resistance. The hypothalamus controls the food consumption behavior of the body and plays a key role in maintaining systemic energy balance. the hypothalamus is capable of sensing the hormones released by the peripheral tissues as well as nutrient substances in the body fluid circulation, thereby regulating the energy consumption of the peripheral tissues and controlling the food consumption behavior of the organism. The dysfunction of the hypothalamus can lead to a series of metabolic disorders that show that the hypothalamus may play a key role in the occurrence and progression of T2D in the early obesity and food-induced T2D studies. In order to study the molecular mechanism of the hypothalamus of non-obese GK rats in the pathogenesis of diabetes mellitus, this study carried out transcriptome sequencing (RNA-seq) on the hypothalamus of GK rats aged 4, 8 and 12, The results are as follows: (1) In Wistar and GK rats, some 13600 genes were detected in the hypothalamus. Of these, 1119, 1381 and 1702 GK rat genes had significant differences in Weeks 4, 8 and 12, respectively. Differential expression of genes indicated that the black skin quality system in the hypothalamus of GK rats had functional disorder and impaired glucose sensing pathway in hypothalamus, which affected the feeding behavior of GK rats and may have an effect on the energy balance of GK rats. (2) 22783 and 25582 mutations (relative to the reference Norwegian rat) were detected in the genes of Wistar and GK rats, which contained 5831 Wistar rat-specific mutations and 8630 GK rat-specific mutations. Among these mutant genes, 767 Wistar rat-specific genes and 1316 GK rat-specific genes were found. The results showed that the number of gene mutations in GK rats was significantly higher than that in Wistar rats in the control group, indicating that many new mutations were fixed and inherited in GK rats during repeated selfing. (3) Through the co-expression network of protein interaction network and hypothalamus transcription group, a series of gene network modules were integrated in combination with the gene mutation of Wistar and GK rats. The genes of these modules have high coexpression and interaction, but also enrich the mutation gene of GK rats, and provide an important basis for revealing the regulation network of the hypothalamus of GK rats. GK rat specific genes in these modules, such as Bad, Map2k2, Adcy3, Adcy2 and Gstm6, have been involved in many important signaling pathways, which may play an important role in the hypothalamus regulation of GK rats. In order to reveal the molecular mechanism in the pathogenesis of T2D, the gene expression and genetic variation of the hypothalamus of GK rats were comprehensively revealed by high-flux transcription group sequencing. It also provides new evidence for the mechanism of the central nervous system hypothalamus in the pathogenesis of T2D. The main innovation points of this study are: (1) The mechanism of impaired glucose sensing pathway in the hypothalamus of GK rats and the relationship between the disturbance of the black skin quality system and the food consumption of GK rats were studied by using the expression of the transcription group of the hypothalamus in the pathogenesis of diabetes mellitus in GK rats. The effect of the regulation of the hypothalamus in the energy balance on the formation of T2D in GK rats is explained. (2) The expression of the transcription group and the gene mutation of GK rats in the pathogenesis of diabetes in GK rats were analyzed, and the effects of the specific genes of GK rats on the regulation of hypothalamus were revealed through the analysis of gene network module.
【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：R587.1

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