中国科学院昆明动物研究所机构知识库

长链非编码RNA（Long noncoding RNA, lncRNA）是一类被定义为长度大于200nt且不具备蛋白编码潜能的转录本，在过去一直被认为是基因组中的“暗物质”。近些年来由于高通量技术的普及以及RNA分子研究技术水平的大幅度提高，越来越多的lncRNA被发现参与多种生物学过程并与多种人类疾病相关，因而受到了科学家们广泛的关注。世界性的人口老龄化问题的日益加重，如何缓解老年性疾病给老人带来的生理上的痛苦以及经济上的负担成为了整个世界亟需解决的问题，保持健康衰老即在衰老的同时保持身体健康或是缓解或解决这一问题的有效办法之一。在自然界中有一些神奇的长寿哺乳动物如裸鼹鼠、布氏鼠耳蝠、北极露脊鲸等，这些物种包括人类在内，均具有相对于近缘物种而言具有极长的寿命的特征，其中裸鼹鼠还具有抗癌特性，这些特征驱使着我们以这些物种为研究对象来探索其中的长寿“奥秘”。本研究以lncRNA为出发点，运用生物信息学方法比较分析lncRNA基因在长寿物种中的特性，试图了解lncRNA在不同长寿物种间的异同以及lncRNA与衰老、健康衰老以及长寿发生过程的潜在相关性。我们首次鉴定并报道裸鼹鼠、布氏鼠耳蝠以及北极露脊鲸的lncRNA的相关特征：与其他物种的lncRNA相似，三个长寿物种的lncRNA较mRNA而言具有表达量低、长度较短等特征，且物种间序列保守性非常低。基于K-mer方法的功能同源分析显示人类中已知与衰老或抗衰老的lncRNA在长寿物种基因组中有大量的功能同源lncRNA（r ≥ 0.9）。我们对裸鼹鼠lncRNA与其抗癌特性进行了相关性分析，结果表明裸鼹鼠lncRNA与人类已知致癌lncRNA的序列相似性极低，共表达结果显示约64%的裸鼹鼠lncRNA 与潜在抑癌基因有非常显著的共表达现象（共表达系数|r|> 0.8, cp value < 0.01），而这一比例在大鼠中仅为60%；我们还发现六条lncRNA与裸鼹鼠的高分子量透明质酸代谢有密切关系，而高分子量透明质酸通路是调控裸鼹鼠细胞不会癌变的强有力途径之一；与长寿蛋白家族sirtuin家族的共表达分析发现一共有337个lncRNA与sirtuin家族有显著正相关共表达关系（r > 0.7, cp value < 0.01）,有545个lncRNA呈现显著负相关共表达关系（r < -0.7, cp value < 0.01），这些结果表明裸鼹鼠lncRNA有极大的可能参与在其抗癌机制以及长寿发生过程。此外，以往的研究发现百岁老人及其后代是研究健康衰老及长寿特性的极有利的研究对象，因此本研究对171个来自百岁老人家庭成员血液样本进行了深度转录组特性，大规模的分析lncRNA的表达特性。通过一系列的分析过滤后，找到了一些潜在与衰老或抗衰老相关的候选lncRNA分子如TBLNC1、TBLNC2以及ARLNC等。通过多维度的实验验证，初步认定TBLNC1和TBLNC2是细胞抗衰老因子；而ARLNC敲除小鼠亦表现出了非常明显的早衰现象如皮肤褶皱、无毛或少毛、驼背、易感染、患白内障等，生化实验结果表明ARLNC通过与GRHL1互作从而影响调控小鼠的毛发生成以及皮肤免疫屏障功能。总的来说，本研究通过生物信息学的分析方法鉴定和探索长寿哺乳动物及百岁老人血液中lncRNA与长寿及衰老之间的潜在关系；同时运用分子、细生化以及转基因小鼠等实验手段来挖掘lncRNA在长寿发生过程中的潜在功能及作用机制，为了解和维系健康衰老进而改善世界人口老龄化现状提供分子基础。 

Long noncoding RNAs (LncRNAs) are broadly defined as transcripts that are longer than 200nt without coding potential that were regarded as “junk DNA” in the past decades. Due to the high popularity of next-sequencing methods and the fast development of RNA research techniques, more and more lncRNAs were found to act as impressive roles in a lot of biological process in recent years, especially in driving and/or inhibiting human diseases. Accelerated aged population has become a wordwide issue, it is estimated that by 2020, 22% of the world population will be aged ≥ 60 years and this number will reach to 29% in 2025, which will lead to a growing number of older people acquiring age-related diseases. Therefore, how to keep healthy for elder people is an urget problem to be solved. In the wonders of nature, some mammals like naked mole rat (Heterocephalus glaber), brandt's bat (Myotis brandtii), bowhead whale (Balaena mysticetus) and human (Homo sapiens) as well, exhibit extremely long lifesan compared with their close species, which attract our attention. To better understand how to maintain healthy ageing, we first identified lncRNAs in three longevous mammals and explore their potential association with ageing and longevity. Similar with other species, lncRNAs in those three species show lower expression，shorter length and significant lack of sequence conservation than mRNA. Prediction of potentially functional orthologous lncRNAs between species based on K-mer method show that plenty of lncRNAs in longevous mammals’ genome show high association with human ageing related lncRNAs (r ≥ 0.9). We also focused on analysis the relevance between lncRNAs and cancer-resistance in the naked mole rat (NMR), and found around 64% NMR-lncRNAs strikingly coexpressed ( |r|> 0.8, cp value < 0.01) with tumor suppressor genes (TSGs). In rat, a tumor prone rodent, only 60% lncRNAs exhibit the same coexpression level with TSGs. Coexpression anlysis indicates there are six NMR-lncRNAs may involve in high molecular weight hyaluronic acid (HMW-HA) pathway in naked mole rat which has been proved as the most powerful trigger of anti-cancer in this endorsed species. Also, a total of 337/545 NMR-lncRNAs show positive/negative correlated expression (r> 0.7 or r<-0.7, cp value < 0.01) with sirtuin protein family members – the most important role in mammals’ lifespan extension, suggesting that NMR-lncRNAs have possible effects on its longevity character. Centenarians and their offspring are good models to study healthy ageing. In this study, we additionally performed deep RNA-seq on 171 individuals from centenarians’ families and did a comprehensive analysis of lncRNA expression among those individuals. After stringent filtering, three lncRNAs named TBLNC1, TBLNC2 and ARLNC were selected as the candidate ageing or healthy ageing related lncRNAs. Silencing or overexpression of TBLNC1 and TBLNC2 respectively will result in altered senescence level in IMR90 and/or HEL1 cells, primarily suggesting that TBLNC1 and TBLNC2 are anti-ageing related factors. ARLNC knock out (KO) mice have a lot of pre-ageing phenotypes such as wrinkled skin at very young age, hairless, kyphosis, easy to get infection, and getting cataract disease. Further biochemistry assay found ARLNC will directly interact with GRHL1 protein in skin tissue and thus regulating hair growth and maintaining skin immune barrier. In this study, we intergrate bioinformatic analysis and multi-dimension experimental methods to elucidate the association between lncRNAs and ageing/anti-ageing process and the possible functions and mechanisms of lncRNAs in keeping healthy ageing, which will provide important molecular basis for reducing the physiological and economical effects that were caused by increasing aged population.