Long non-coding RNA GATA6-AS1 is mediated by N6-methyladenosine methylation and inhibits the proliferation and metastasis of gastric cancer

BACKGROUND Through experimental research on the biological function of GATA6-AS1,it was confirmed that GATA6-AS1 can inhibit the proliferation,invasion,and migration of gastric cancer cells,suggesting that GATA6-AS1 plays a role as an anti-oncogene in the occurrence and development of gastric cancer.Further experi-ments confirmed that the overexpression of fat mass and obesity-associated protein(FTO)inhibited the expression of GATA6-AS1,thereby promoting the occurrence and development of gastric cancer.AIM To investigate the effects of GATA6-AS1 on the proliferation,invasion and migration of gastric cancer cells and its mechanism of action.METHODS We used bioinformatics methods to analyze the Cancer Genome Atlas(https://portal.gdc.cancer.gov/.The Cancer Genome Atlas)and download expression data for GATA6-AS1 in gastric cancer tissue and normal tissue.We also constructed a GATA6-AS1 lentivirus overexpression vector which was transfected into gastric cancer cells to investigate its effects on proliferation,migration and invasion,and thereby clarify the expression of GATA6-AS1 in gastric cancer and its biological role in the genesis and development of gastric cancer.Next,we used a database(http://starbase.sysu.edu.cn/starbase2/)to analysis GATA6-AS1 whether by m6A methylation modify regulation and predict the methyltransferases that may methylate GATA6-AS1.Furthermore,RNA immunoprecipitation experiments confirmed that GATA6-AS1 was able to bind to the m6A methylation modification enzyme.These data allowed us to clarify the ability of m6A methylase to influence the action of GATA6-AS1 and its role in the occurrence and development of gastric cancer.RESULTS Low expression levels of GATA6-AS1 were detected in gastric cancer.We also determined the effects of GATA6-AS1 overexpression on the biological function of gastric cancer cells.GATA6-AS1 had strong binding ability with the m6A demethylase FTO,which was expressed at high levels in gastric cancer and negatively correlated with the expression of GATA6-AS1.Following transfection with siRNA to knock down the expression of FTO,the expression levels of GATA6-AS1 were up-regulated.Finally,the proliferation,migration and invasion of gastric cancer cells were all inhibited following the knockdown of FTO expression.CONCLUSION During the occurrence and development of gastric cancer,the overexpression of FTO may inhibit the expression of GATA6-AS1,thus promoting the proliferation and metastasis of gastric cancer.

Expression and significance of fat mass and obesity associated gene and forkhead transcription factor O1 in non-alcoholic fatty liver disease

Background Non-alcoholic fatty liver disease （NAFLD） is a complex disorder and has been closely linked to obesity.The fat mass and obesity-associated （FTO） gene is a newly discovered gene related to obesity,which enhances oxidative stress and tipogenesis in NAFLD.The forkhead transcription factor O1 （FoxO1） is another important gene involved in NAFLD,which causes lipid disorders when insulin resistance appears in the liver.However,the interactions between FTO and FoxO1 during the pathogenesis of NAFLD have not been fully elucidated.This study was designed to identify the relationship between these two factors that are involved in the development of NAFLD.Methods This study includes two parts referred to as animal and cell experiments.Twelve female SPF C57BL/6 mice were fed a high-fat diet to serve as an NAFLD animal model.Aspartate aminotransferase （AST）,alanine aminotransferase （ALT）,total triglyceride （TG）,total cholesterol （TC）,alkaline phosphatase （ALP）,high-density lipoprotein （HDL）,and low-density lipoprotein （LDL） were measured.Immunohistochemical analysis was used to detect the expression and histological localization of FTO,FoxO1,and adenosine monophosphate （AMP）-activated protein kinase （AMPK）.The L02 cells were exposed to high fat for 24,48,or 72 hours.Oil red O staining was used to detect intracellular lipid droplets.Reverse transcription-polymerase chain reaction was used for analyzing the levels of FTO and FoxO1 mRNA.Results At the end of 10 weeks,ALP,ALT,AST,and LDL were significantly increased （P ＜0.01）,while TC and TG were also significantly higher （P ＜0.05）.In addition,HDL was significantly decreased （P ＜0.05）.The FTO and FoxO1 proteins were weakly expressed in the control group,but both FTO and FoxO1 were expressed significantly higher （P ＜0.01） in the experimental group,and the expression of the two factors was significantly correlated.AMPK in the high-fat group showed a low level of correlation with FTO,but not with FoxO1.Oil Red O staining results showed that the cells cultured in 50％ fetal bovine serum for 24,48,or 72 hours exhibited steatosis.FTO and FoxO1 mRNA were increased in the high-fat group compared with the normal group （P ＜0.01）.The expression levels of FTO and FoxO1 mRNA were the highest at 48 hours （P ＜0.05）.Conclusions A high-fat diet leads to higher expression of FTO,phosphorylation of FoxO1,and decreased phosphorylation of AMPK.These results suggest that the interactions between FTO and FoxO1 are closely related to the pathogenesis of NAFLD.

耐力训练对大鼠FTO基因表达影响及与摄食量关系研究

目的:研究耐力训练对大鼠FTO基因表达的影响以及与摄食量的关系。方法:以SD大鼠为研究对象,将大鼠分为对照组(C组)和运动训练组(E组),以12周无负重游泳为运动手段,测定肝脏、骨骼肌、脂肪组织和下丘脑组织中FTO基因mRNA表达、大鼠体重、肾周与附睾周围脂肪重量及脂肪重量与体重百分比、大鼠每天摄食量。结果:FTO基因mRAN在骨骼肌、脂肪组织和下丘脑中表达均显著高于肝脏组织,下丘脑显著高于骨骼肌和脂肪组织,脂肪组织与骨骼肌未见显著性差异,耐力训练对肝脏、骨骼肌和脂肪组织中FTO基因mRNA表达未见显著性影响,而脑组织表达显著升高;大鼠体重在不同的对应时间点,运动训练组与对照组未见显著性差异;大鼠摄食量在不同对应时间点,运动训练组显著高于对照组;肾周及附睾周围脂肪组织重量及脂肪重与体重百分比运动训练组显著低于对照组。结论:耐力训练可以提高下丘脑中FTO基因表达,从而刺激大鼠提高摄食量,而运动能量的消耗抵消了因摄食增加引起的体重增加。

单肥胖基因MC4R及FTO危险等位基因型分布与儿童肥胖的相关性研究

目的了解单肥胖基因MC4R常见SNP位点、FTO危险等位基因型与儿童单纯性肥胖的相关性。方法纳入伊犁地区7~13岁超重肥胖学龄儿童150例,年龄、性别匹配的202例正常体重儿童为对照组,电离飞行时间质谱(MALDI-TOF MS)法检测两组儿童的MC4R基因rsl7782313以及FTO基因危险等位基因位点rs9939609、rsl421085、rs8050136、“17817449的基因型分布,同时完善生化指标(空腹血糖、胰岛素浓度、血脂等)的检测。结果两组FTO基因rsl421085的等位基因频数差异具有统计学意义(P V0.05),“17782313、rs9939609、rsl421085、rs8050136、rsl7817449的基因型分布差异无统计学意义(P>0.05),两组rs9939609、“1421085、rs8050136、rsl7817449组成的单体型TTCT,CTCT分布差异具有统计学意义(P<0.05)o rs9939609的AA基因型较AT、TT基因型患儿的收缩压更高,腰围更大,空腹胰岛素及胰岛素抵抗因子更高。结论FTO基因单体型TTCT.CTCT与儿童肥胖相关,携带FTO基因rs9939609位点AA基因型的儿童更容易出现血压、腰围及胰岛素代谢异常。

人脂肪与肥胖相关基因蛋白在结、直肠癌及肝癌组织中的表达及意义

目的:探讨人脂肪与肥胖相关(FTO)基因蛋白在结、直肠癌和肝癌组织中的表达及意义。方法:采用免疫组化染色方法检测61例结、直肠癌以及相应59例癌旁组织、68例肝癌以及相应67例癌旁组织中FTO基因蛋白的表达。结果:FTO在结、直肠癌与癌旁组织的表达阳性率分别为63.93%(39/61)、37.29%(22/59),结、直肠癌组织中的表达明显高于癌旁组织,差异有统计学意义(P<0.05);FTO在肝癌与癌旁组织的表达阳性率分别为63.24%(43/68),88.06%(59/67),两者比较差异无统计学意义(P>0.05)。结论:FTO基因蛋白在结、直肠癌组织中呈高表达,在结、直肠癌的发生中发挥作用。

Effect of demethyltransferase FTO on tumor progression

N6-methyladenosine(m6A)modification is the most widespread and conserved internal mRNA modification in mammalian cells.It greatly affects genetic regulation by enhancing the involvement of diverse cellular enzymes and thus,plays a significant role in basic life processes.Numerous studies on m6A modification identified FTO as a crucial demethylase that participates in various biological processes.Not only does FTO play a pivotal role in obesity-related conditions,but it also influences the occurrence,development,and prognosis of several cancers,such as acute myeloid leukemia,breast cancer,liver cancer,and lung cancer.Moreover,FTO also shows a close association with immunity and viral infections.This article summarized the molecular mechanism of FTO in tumorigenesis and tumor progression.

Advancement in genetic variants conferring obesity susceptibility from genome-wide association studies

Obesity prevalence has increased in recent years. Lifestyle change fuels obesity, but genetic factors cause more than 50% of average variations in obesity. The advent of genome-wide association studies （GWAS） has hastened the progress of polygenic obesity research. As of this writing, more than 73 obesity susceptibility loci have been identified in ethnic groups through GWAS. The identified loci explain only 2% to 4% of obesity heritability, thereby indicating that a large proportion of loci remain undiscovered. Thus, the next step is to identify and confirm novel loci, which may exhibit smaller effects and lower allele frequencies than established loci. However, achieving these tasks has been difficult for researchers. GWAS help researchers discover the causal loci. Moreover, numerous biological studies have been performed on the polygenic effects on obesity, such as studies on fat mass- and obesity-associated gene （FTO）, but the role of these polygenic effects in the mechanism of obesity remains unclear. Thus, obesity-causing variations should be identified, and insights into the biology of polygenic effects on obesity are needed.

FTO-mediated m6A modification alleviates autoimmune uveitis by regulating microglia phenotypes via the GPC4/TLR4/NF-κB signaling axis

Uveitis,a vision-threatening inflammatory disease worldwide,is closely related to resident microglia.Retinal microglia are the main immune effector cells with strong plasticity,but their role in uveitis remains unclear.N6-methyladenosine(m^(6)A)modification has been proven to be involved in the immune response.Therefore,we in this work aimed to identify the potentially crucial m^(6)A regulators of microglia in uveitis.Through the single-cell sequencing(scRNA-seq)analysis and experimental verification,we found a significant decrease in the expression of fat mass and obesity-associated protein(FTO)in retinal microglia of uveitis mice and human microglia clone 3(HMC3)cells with inflammation.Additionally,FTO knockdown was found to aggravate the secretion of inflammatory factors and the mobility/chemotaxis of microglia.Mechanistically,the RNA-seq data and rescue experiments showed that glypican 4(GPC4)was the target of FTO,which regulated microglial inflammation mediated by the TLR4/NF-κB pathway.Moreover,RNA stability assays indicated that GPC4 upregulation was mainly regulated by the downregulation of the m^(6)A“reader”YTH domain family protein 3(YTHDF3).Finally,the FTO inhibitor FB23-2 further exacerbated experimental autoimmune uveitis(EAU)inflammation by promoting the GPC4/TLR4/NF-κB signaling axis,and this could be attenuated by the TLR4 inhibitor TAK-242.Collectively,a decreased FTO could facilitate microglial inflammation in EAU,suggesting that the restoration or activation of FTO function may be a potential therapeutic strategy for uveitis.