Together is Better: mRNA Co-Encapsulation in Lipoplexes is Required to Obtain Ratiometric Co-Delivery and Protein Expression on the Single Cell Level.
Adv Sci (Weinh). 2021 Dec 16:e2102072. doi: 10.1002/advs.202102072. Epub ahead of print. PMID: 34913603.
|Authors/Editors:||Zhang H, Bussmann J, Huhnke FH, Devoldere J, Minnaert AK, Jiskoot W, Serwane F, Spatz J, Röding M, De Smedt SC, Braeckmans K, Remaut K.|
Liposomes can efficiently deliver messenger RNA (mRNA) into cells. When mRNA cocktails encoding different proteins are needed, a considerable challenge is to efficiently deliver all mRNAs into the cytosol of each individual cell. In this work, two methods are explored to co-deliver varying ratiometric doses of mRNA encoding red (R) or green (G) fluorescent proteins and it is found that packaging mRNAs into the same lipoplexes (mingle-lipoplexes) is crucial to efficiently deliver multiple mRNA types into the cytosol of individual cells according to the pre-defined ratio. A mixture of lipoplexes containing only one mRNA type (single-lipoplexes), however, seem to follow the “first come – first serve” principle, resulting in a large variation of R/G uptake and expression levels for individual cells leading to ratiometric dosing only on the population level, but rarely on the single-cell level. These experimental observations are quantitatively explained by a theoretical framework based on the stochasticity of mRNA uptake in cells and endosomal escape of mingle- and single-lipoplexes, respectively. Furthermore, the findings are confirmed in 3D retinal organoids and zebrafish embryos, where mingle-lipoplexes outperformed single-lipoplexes to reliably bring both mRNA types into single cells. This benefits applications that require a strict control of protein expression in individual cells.