tRNA modification enzyme- dependent redox homeostasis regulates synapse formation and memory

• 成果类型: Article
• 署名作者: Madhwani, Kimberly R.; Sayied, Shanzeh; Ogata, Carlson H.; Hogan, Caley A.; Lentini, Jenna M.; Mallik, Moushami; Dumouchel, Jennifer L.; Storkebaum, Erik; Fu, Dragony; O'Connor -Giles, Kate M.
• 署名单位: Brown University; Brown University; Brown University; University of Wisconsin System; University of Wisconsin Madison; University of Rochester; Radboud University Nijmegen; Brown University; Brown University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-8561
• DOI: 10.1073/pnas.2317864121
• 发表日期: 2024-11-12
• 关键词: neuronal gene-expression; oxidative stress; drosophila-melanogaster; selenium metabolism; wobble position; taste memory; ii receptor; selenoprotein; methyltransferase; protein

摘要

Post- transcriptional modification of RNA regulates gene expression at multiple levels. ALKBH8 is a tRNA- modifying enzyme that methylates wobble uridines in a subset of tRNAs to modulate translation. Through methylation of tRNA- selenocysteine, ALKBH8 promotes selenoprotein synthesis and regulates redox homeostasis. Pathogenic variants in ALKBH8 have been linked to intellectual disability disorders in the human population, but the role of ALKBH8 in the nervous system is unknown. Through in vivo studies in Drosophila, we show that ALKBH8 controls oxidative stress in the brain to restrain synaptic growth and support learning and memory. ALKBH8 null animals lack wobble uridine methylation and exhibit reduced protein synthesis in the nervous system, including a specific decrease in selenoprotein levels. Either loss of ALKBH8 or independent disruption of selenoprotein synthesis results in ectopic synapse formation. Genetic expression of antioxidant enzymes fully suppresses synaptic overgrowth in ALKBH8 null animals, confirming oxidative stress as the underlying cause of dysregulation. ALKBH8 null animals also exhibit associative memory impairments that are reversed by pharmacological antioxidant treatment. Together, these findings demonstrate the critical role of tRNA wobble uridine modification in redox homeostasis in the developing nervous system and reveal antioxidants as a potential therapy for ALKBH8- associated intellectual disability.