Lipid nanoparticles (LNPs) are currently in the spotlight as delivery systems for mRNA therapeutics and have been used in the Pfizer/BioNTech and Moderna COVID-19 vaccines. mRNA-LNP formulations have been indicated to require strict control, including maintenance at fairly low temperatures during their transport and storage. Since it is a new pharmaceutical modality, there is a lack of information on the systematic investigation of how storage and handling conditions affect the physicochemical properties of mRNA-LNPs and their protein expression ability. In this study, using the mRNA-LNPs with standard composition, we evaluated the effects of temperature, cryoprotectants, vibration, light exposure, and syringe aspiration from the vials on the physicochemical properties of nanoparticles in relation to their in vitro/in vivo protein expression ability. Among these factors, storage at −80 °C without a cryoprotectant caused a decrease in protein expression, which may be attributed to particle aggregation. Exposure to vibration and light also caused similar changes under certain conditions. Exposure to these factors can occur during laboratory and hospital handling. It is essential to have sufficient knowledge of the stability of mRNA-LNPs in terms of their physical properties and protein expression ability at an early stage to ensure reproducible research and development and medical care.

No abstract

The H3K4 methyltransferase SETD1A plays a crucial role in leukemia cell survival through its noncatalytic FLOS domain‐mediated recruitment of cyclin K and regulation of DNA damage response genes. In this study, we identify a functional nuclear localization signal in and interaction partners of the FLOS domain. Our screen for FLOS domain‐binding partners reveals that the SETD1A FLOS domain binds mitosis‐associated proteins BuGZ/BUB3. Inhibition of both cyclin K and BuGZ/BUB3‐binding motifs in SETD1A shows synergistic antileukemic effects. BuGZ/BUB3 localize to SETD1A‐bound promoter‐TSS regions and SETD1A‐negative H3K4me1‐positive enhancer regions adjacent to SETD1A target genes. The GLEBS motif and intrinsically disordered region of BuGZ are required for both SETD1A‐binding and leukemia cell proliferation. Cell‐cycle‐specific SETD1A restoration assays indicate that SETD1A expression at the G1/S phase of the cell cycle promotes both the expression of DNA damage response genes and cell cycle progression in leukemia cells.