N1-Methylpseudouridine as a Molecular Regulator of mRNA Vaccine Immunogenicity and Translation Efficiency
DOI:
https://doi.org/10.64229/v8t8pk92Keywords:
N1-methylpseudouridine, mRNA vaccines, Innate immune recognition, Translation efficiency, RNA stability, Nucleoside modificationAbstract
The messenger RNA (mRNA) vaccine platform has enabled rapid development of preventive and therapeutic immunotherapies, yet unmodified mRNA inherently activates innate immune sensors, triggering interferon responses that destabilize mRNA and impair protein translation. This review critically examines the chemical and structural characteristics of N1-methylpseudouridine (m1Ψ) and evaluates its impacts on innate immune recognition, mRNA stability, and translational efficiency. Incorporation of m1Ψ alters base-pairing and stacking interactions, reducing recognition by pattern-recognition receptors including Toll-like receptors and RIG-I-like receptors. Recent mechanistic studies have revealed that m1Ψ evades immune detection through impaired endolysosomal processing by RNase T2 and phospholipase D enzymes, providing a molecular basis for its reduced immunogenicity. Compared with other modified nucleosides such as pseudouridine (Ψ) and 5-methylcytidine (m5C), m1Ψ demonstrates superior suppression of innate immune activation and enhanced protein expression. However, emerging evidence suggests context-dependent effects, including potential concerns regarding 100% m1Ψ substitution in cancer applications that warrant careful consideration. Recent advances in understanding m1Ψ-mediated translation dynamics__including ribosome profiling and cryo-electron microscopy studies__have revealed that this modification directly modulates elongation kinetics and initiation efficiency in a sequence-dependent manner, challenging earlier assumptions that its effects are solely immune-mediated. Despite these advances, critical knowledge gaps remain regarding dose-dependent effects, long-term adaptive immune outcomes, and optimization for self-amplifying RNA platforms. This review synthesizes current mechanistic understanding of m1Ψ as a molecular regulator, evaluates competing hypotheses in the field, and identifies priority areas for future investigation that address the translational potential and limitations of this modification.
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Copyright (c) 2026 Shoaib Manzoor, Sidra Haseen, Umar Javaid, Rutab Rizwan (Author)
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