Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
Nat Commun. 2022 Aug 25;13(1):5003. doi: 10.1038/s41467-022-32766-3.
Oligodendrocytes are specialized cells that confer neuronal myelination in the central nervous system. Leukodystrophies associated with oligodendrocyte deficits and hypomyelination are known to result when a number of tRNA metabolism genes are mutated. Thus, for unknown reasons, oligodendrocytes may be hypersensitive to perturbations in tRNA biology. In this study, we survey the tRNA transcriptome in the murine oligodendrocyte cell lineage and find that specific tRNAs are hypomodified in oligodendrocytes within or near the anticodon compared to oligodendrocyte progenitor cells (OPCs). This hypomodified state may be the result of differential expression of key modification enzymes during oligodendrocyte differentiation. Moreover, we observe a concomitant relationship between tRNA hypomodification and tRNA decoding potential; observing oligodendrocyte specific alterations in codon optimality-mediated mRNA decay and ribosome transit. Our results reveal that oligodendrocytes naturally maintain a delicate, hypersensitized tRNA/mRNA axis. We suggest this axis is a potential mediator of pathology in leukodystrophies and white matter disease when further insult to tRNA metabolism is introduced.
少突胶质细胞是中枢神经系统中赋予神经元髓鞘形成的特化细胞。已知当许多 tRNA 代谢基因发生突变时,与少突胶质细胞缺陷和少突胶质细胞发育不良相关的白质营养不良会发生。因此,由于未知原因,少突胶质细胞可能对 tRNA 生物学的干扰高度敏感。在这项研究中,我们调查了小鼠少突胶质细胞谱系中的 tRNA 转录组,发现在与少突胶质前体细胞(OPC)相比,少突胶质细胞内或附近的反密码子中存在特定的 tRNA 低修饰。这种低修饰状态可能是少突胶质细胞分化过程中关键修饰酶表达差异的结果。此外,我们观察到 tRNA 低修饰与 tRNA 解码能力之间存在伴随关系;观察到密码子最优性介导的 mRNA 衰减和核糖体转运中存在少突胶质细胞特异性改变。我们的结果表明,少突胶质细胞自然维持着一个微妙的、高度敏感的 tRNA/mRNA 轴。当进一步引入 tRNA 代谢损伤时,我们认为该轴可能是白质营养不良和白质疾病病理的潜在介质。