HHEX基因rs1111875G/A多态性与妊娠糖尿病的关系

目的研究山东济宁地区造血干细胞表达同源盒(HHEX)基因rs1111875单核苷酸多态性(SNP)的等位基因、基因型频率分布,探讨其与妊娠糖尿病(GDM)及相关代谢指标的关系。方法选取24～28周妊娠期妇女(451例)为研究对象,进行75 g口服葡萄糖耐量试验(OGTT),其中203例诊断为妊娠糖尿病(GDM组),248例诊断为妊娠糖耐量正常(NGT组),应用聚合酶链反应—限制性片段长度多态性(PCR-RFLP)方法检测HHEX基因rs1111875G/A多态性,并进行生化指标检测,分别用胰岛β细胞分泌功能指数(HOMA-B)和稳态模型胰岛素抵抗指数(HOMA-IR)评估胰岛β细胞功能及胰岛素抵抗。结果 GDM组GG、GA、AA三种基因型频率分别为9.9%、42.4%、47.8%,NGT组分别为4.0%、40.7%、55.2%,两组比较,P均<0.05。GDM组G、A等位基因频率分别为31.0%、69.0%,NGT组分别为24.4%、75.6%,两组比较,P<0.05。G等位基因携带者患GDM风险是A等位基因的1.40倍(OR=1.395,95%CI为1.040～1.871,P=0.026)。GG基因型患GDM的风险是AA基因型的4.13倍(OR=4.129,95%CI为1.589～10.731,P=0.004)。GG与AA基因型相比,1 h PG显著升高(P<0.01),FINS、HO-MA-B显著降低(P均<0.01)。结论 HHEX基因rs1111875G/A多态性与山东济宁地区GDM有关,G等位基因可能是其风险等位基因,HHEX基因可能是该地区GDM易感基因之一。

HHEX基因多态性与中国北方汉族人群精神分裂症及合并2型糖尿病发病的遗传学研究

目的探讨2型糖尿病易感基因HHEX与中国汉族人群2型糖尿病、精神分裂症以及精神分裂症合并2型糖尿病发病的关系。方法采用群体遗传学研究策略,以中国北方汉族人群331例精神分裂症患者、166例精神分裂症合并2型糖尿病患者、229例单纯2型糖尿病患者和389例健康对照个体为研究对象,采用TaqMan探针方法检测HHEX基因rs1111875位点基因型。结果拟合优度χ^2检验分析显示rs1111875基因型频数分布在上述4个群体中均符合Hardy-Weinberg平衡定律（P〉0.05）;Pearsonχ^2检验显示HHEX基因rs1111875位点等位基因、基因型频率在上述4组中差异显著（χ-2=14.770,df=3,P=0.002;χ^2=15.102,df=6,P=0.019）。遗传学关联分析发现,与健康对照组比较,单纯2型糖尿病组rs1111875位点等位基因频率差异显著（χ^2=3.905,P=0.048）,单纯精神分裂症组或精神分裂症合并2型糖尿病组,rs1111875位点等位基因、基因型频率均无显著差异（P〉0.05）,结论 HHEX基因rs1111875位点与中国北方汉族人群2型糖尿病发病相关联,而与精神分裂症以及精神分裂症合并2型糖尿病发病无关联。

小鼠HHEX基因和蛋白的生物信息学分析

目的:分析HHEX基因序列及蛋白质的结构特点,研究其在发育过程中的作用。方法:采用生物信息学方法分析预测HHEX基因序列、蛋白质结构,以及与其他蛋白质的相互作用。结果:小鼠HHEX基因cDNA全长1771 bp,CDS区全长816 bp,其编码的HHEX蛋白含271个氨基酸残基,相对分子质量为30×103,为不稳定蛋白,具有α螺旋、无规卷曲、延伸链与β转角;功能分析表明HHEX蛋白是参与调控关键发育过程的转录调控因子,并与EOMES、FOXA2、KDR、WNT7A、HEXB、TG、SLC30A8、IGF2BP2及CDKAL1蛋白有相互作用。结论:HHEX基因及蛋白生物信息学分析为HHEX基因及蛋白的相关研究提供了重要的信息基础。

Zebrafish hhex-null mutant develops an intrahepatic intestinal tube due to de-repression of cdx1b and pdx1

The hepatopancreatic duct (HPD) system links the liver and pancreas to the intestinal tube and is composed of the extrahepatic biliary duct, gallbladder, and pancreatic duct. Haematopoietically expressed-homeobox (Hhex) protein plays an essential role in the establishment of HPD;however, the molecular mechanism remains elusive. Here, we show that zebrafish hhex-null mutants fail to develop the HPD system characterized by lacking the biliary marker Annexin A4 and the HPD marker sox9b. The hepatobiliary duct part of the mutant HPD system is replaced by an intrahepatic intestinal tube characterized by expressing the intestinal marker fatty acid-binding protein 2a (fabp2a). Cell lineage analysis showed that this intrahepatic intestinal tube is not originated from hepatocytes or cholangiocytes. Further analysis revealed that cdx1b and pdx1 are expressed ectopically in the intrahepatic intestinal tube and knockdown of cdx1b and pdx1 could restore the expression of sox9b in the mutant. Chromatin-immunoprecipitation analysis showed that Hhex binds to the promoters of pdx1 and cdx1b genes to repress their expression. We therefore propose that Hhex, Cdx1b, Pdx1, and Sox9b form a genetic network governing the patterning and morphogenesis of the HPD and digestive tract systems in zebrafish.

慈溪地区2型糖尿病易感基因分析

目的探讨HHEX基因rs1111875、CDKAL1基因rs7756992、TCF7L2基因rs12255372和rs7903146的多态性与慈溪地区2型糖尿病（T2DM）的相关性。方法应用pyromark Q96 ID 焦磷酸测序仪对543例正常人群和310例T2DM患者HHEX基因rs1111875、CDKAL1基因rs7756992、TCF7L2基因rs12255372和rs7903146的多态性分析。结果 TCF7L2基因rs7903146位点的基因型和等位基因分布糖尿病组和健康人群组之间差异有统计学意义（P〈0.05），但rs12255372位点的基因型和等位基因分布两组差异无统计学意义，HHEX基因rs1111875位点和CDKAL1基因rs7756992位点的基因型和等位基因分布两组差异也无统计学意义。结论慈溪地区的人群中，TCF7L2基因可能是2型糖尿病的易感基因之一，其SNP位点rs7903146变异可能与2型糖尿病发病密切相关。

Future of liver transplantation: Non-human primates for patient-specific organs from induced pluripotent stem cells

Strategies to fill the huge gap in supply versus demand of human organs include bioartificial organs, growing humanized organs in animals, cell therapy, and implantable bioengineered constructs. Reproducing the complex relations between different cell types, generation of adequate vasculature, and immunological complications are road blocks in generation of bioengineered organs, while immunological complications limit the use of humanized organs produced in animals. Recent developments in induced pluripotent stem cell (iPSC) biology offer a possibility of generating human, patient-specific organs in non-human primates (NHP) using patient-derived iPSC and NHP-derived iPSC lacking the critical developmental genes for the organ of interest complementing a NHP tetraploid embryo. The organ derived in this way will have the same human leukocyte antigen (HLA) profile as the patient. This approach can be curative in genetic disorders as this offers the possibility of gene manipulation and correction of the patient's genome at the iPSC stage before tetraploid complementation. The process of generation of patient-specific organs such as the liver in this way has the great advantage of making use of the natural signaling cascades in the natural milieu probably resulting in organs of great quality for transplantation. However, the inexorable scientific developments in this direction involve several social issues and hence we need to educate and prepare society in advance to accept the revolutionary consequences, good, bad and ugly.

Genetic variants at 10q 23.33 are associated with plasma lipid levels in a Chinese population

Plasma lipid abnormalities are implicated in the pathogenic process of type 2 diabetes. The IDE-KIFII-HHEX gene cluster on chromosome 10q23.33 has been identified as a susceptibility locus for type 2 diabetes. We hy- pothesized that genetic variants at 10q23.33 may be associated with plasma lipid concentrations. Seven tagging single nucleotide polymorphisms （SNPs： rs7923837, rs2488075, rs947591, rs11187146, rs5015480, rs4646957 and rs1111875） at 10q23.33 were genotyped in 3,281 subjects from a Han Chinese population, using the Taq- Man OpenArray and Sequenom MassARRAY platforms. Multiple linear regression analyses showed that SNP rs7923837 in the 3＂-flanking region of HHEX was significantly associated with triglyceride levels （P = 0.019, 0.031 mmol/L average decrease per minor G allele） and that rs2488075 and rs947591 in the downstream region of HHEX were significantly associated with total cholesterol levels （P = 0.041, 0.058 mmol/L average decrease per minor C allele and P = 0.018, 0.063 mmol/L average decrease per minor A allele, respectively）. However, the other four SNPs （rs11187146, rs5015480, rs4646957 and rs1111875） were not significantly associated with any plasma lipid concentrations in this Chinese population. Our data suggest that genetic variants in the IDE-KIF11- HHEX gene cluster at 10q23.33 may partially explain the variation of plasma lipid levels in the Hart Chinese pop- ulation. Further studies are required to confirm these findings in other populations.

Cdx1b protects intestinal cell fate by repressing signaling networks for liver specification

In mammals,the expression of the homeobox family member Cdx2/CDX2 is restricted within the intestine.Conditional ablation of the mouse Cdx2 in the endodermal cells causes a homeotic transformation of the intestine towards the esophagus or gastric fate.In this report,we show that null mutants of zebrafish cdx1b,encoding the counterpart of mammalian CDX2,could survive more than 10 days post fertilization,a stage when the zebrafish digestive system has been well developed.Through RNA sequencing(RNA-seq)and single-cell sequencing(sc RNA-seq)of the dissected intestine from the mutant embryos,we demonstrate that the loss-of-function of the zebrafish cdx1b yields hepatocyte-like intestinal cells,a phenotype never observed in the mouse model.Further RNA-seq data analysis,and genetic double mutants and signaling inhibitor studies reveal that Cdx1b functions to guard the intestinal fate by repressing,directly or indirectly,a range of transcriptional factors and signaling pathways for liver specification.Finally,we demonstrate that heat shock-induced overexpression of cdx1b in a transgenic fish abolishes the liver formation.Therefore,we demonstrate that Cdx1b is a key repressor of hepatic fate during the intestine specification in zebrafish.