Time-ordered-expression mRNA (TOE mRNA) for melanoma RNA vaccines

Area of Science:

• Biotechnology
• Immunology
• Molecular Biology

Background:

• Modified messenger RNA (mRNA) technology has revolutionized vaccine development.
• Adjuvants can boost innate immune activation and vaccine efficacy.
• Suboptimal vaccine kinetics can impair mRNA translation and vaccine potency via mTORC1 inhibition.

Purpose of the Study:

• To develop a novel mRNA platform for improved vaccine kinetics and efficacy.
• To overcome limitations of current mRNA vaccine designs related to immune activation timing.
• To enhance antitumor immune responses using a precisely controlled expression system.

Main Methods:

• Development of time-ordered-expression mRNA (TOE mRNA) utilizing ADAR-mediated A-to-I base editing.
• Engineering mRNA to express antigen immediately and adjuvant with a 12-hour delay.
• Utilizing TOE mRNA encoding a tumor neoantigen and an IL-12 adjuvant in preclinical models.

Main Results:

• TOE mRNA ensures immediate antigen translation followed by delayed adjuvant expression.
• Delayed adjuvant release sustains the mTORC1 pathway activation and robust antigen expression.
• Vaccines employing TOE mRNA demonstrated significantly enhanced antitumor immune responses.

Conclusions:

• TOE mRNA technology offers a strategy to optimize mRNA vaccine kinetics.
• This approach overcomes limitations associated with premature innate immune over-activation.
• TOE mRNA represents a promising platform for next-generation, highly effective mRNA vaccines.