Abstract
The development of next-generation mucosal mRNA vaccines is promising but extremely challenging. Major efforts have been focused on optimizing delivery systems, whereas it is still unknown whether the intrinsic quality of IVT mRNA significantly impacts the potency of airway inoculated mRNA vaccines. Here, we systematically demonstrate the mucosal mRNA vaccine requires a higher standard of purification and tailor-designed sequence to fulfil its potency compared to the parenteral route inoculated counterpart. We found double strand RNA (dsRNA) contaminants are prone to trigger innate immunoreaction in the airway that activates the mRNA degradation mechanism, thereby diminishing the mRNA expression and subsequent antigen-specific immune responses. To address these challenges, we developed a strategy that combines optimized untranslated regions (UTRs) screened from endogenous genes of pulmonary cells with affinity chromatography-based purification which removes almost all the dsRNA contaminants. The optimized mRNA administered via the airway route not only demonstrates superior protein expression (30-fold increase) and reduces inflammation in the lung, but also promotes robust immunity comprising significantly elevated systemic, cellular, and mucosal immune responses, which is in stark contrast to intramuscular injected counterpart that displays less pronounced benefits. Our findings offer new insight into the development of mucosal mRNA therapeutics from an overlooked but crucial perspective of optimizing mRNA components.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
We have found many typos and errors in previous uploaded version.e.g. the zip code of institution 5 was missing, the schematic of Fig 6g is not consistant with the description in the text. We have thouroughly conrrected these errors in order to avoid miss leading the readers. Thank you for helping replace the old version preprint.
