PhD Scientific Days 2025

Molecular Medicine V.

Characterization of the Role of the Lymphatic Vasculature in Organ-specific Responses Induced by Nucleoside-modified mRNA-based Platforms

Name of the presenter

Molnár Kornél

Institute/workplace of the presenter

Semmelweis University, Department of Physiology

Authors

Kornél Molnár¹, Gábor Kovács¹, Stella Sági Márta¹, Éva Kemecsei¹, Zoltán Lipinszki², Babak J. Mehrara³, Raghu P. Kataru³, Norbert Pardi⁴, Zoltán Jakus¹

1: Semmelweis University, Department of Physiology
2: Biological Research Centre, Szeged, Hungary
3: Sloan Kettering Cancer Center, New York, NY, USA
4: University of Pennsylvania, Philadelphia, PA, USA

Text of the abstract

Introduction:Nucleoside-modified lipid nanoparticle encapsulated messenger RNAs (mRNA-LNPs) have gained major scientific interest. The mRNA-LNP vaccines can induce significant humoral immune response, although the mechanisms involved in this process are still not fully known. The lymphatics plays a key role in various immune processes, but its involvement in the mRNA-LNP vaccine-induced immune response requires further investigation.
Aim:We aimed to characterize the role of the local lymphatics in nucleoside-modified mRNA-LNP induced organ-specific responses in mouse models.
Method:We injected Dil-fluorophore labeled LNPs or eGFP-encoding mRNA-LNPs into the hind limbs of wild-type mice, then tissue samples were collected from the injection site and the regional lymph node. Thereafter, paraffin-based histology followed by fluorescent immunostaining or flow cytometry analysis were performed. Transgenic mice were injected with influenza hemagglutinin (HA) encoding mRNA-LNPs in lymphatic-deficient skin regions, and anti-HA antibody levels in peripheral blood were measured by ELISA and hemagglutination inhibition assay.
Result:We detected eGFP-expressing cells at the injection site and observed eGFP expression in some lymphatic endothelial cells. Following mRNA-LNP injection, certain immune cells infiltrated the regional lymph node. In the popliteal lymph node, the LNP accumulating cells were mostly neutrophils and macrophages, whereas amongst GFP-expressing cells, dendritic cells (DCs) and subcapsular sinus macrophages (SSMs) were the most numerous. Mice with impaired lymphatics showed reduced antibody responses to HA mRNA-LNP vaccination.
Conclusion:Our results suggest that at least four lymphatic-dependent processes are involved in the mechanism of action of nucleoside-modified mRNA-LNPs. A part of lymphatic endothelial cells take up and express mRNA-LNPs. mRNA-LNPs dissolved in the lymph enter the lymph nodes. Dendritic cells take up and transport the LNPs and express the mRNAs. Neutrophils and macrophages take up and transport mRNA-LNPs but barely express them. Our findings indicate that the local lymphatic vasculature is essential for generating an adequate immune response to mRNA-LNP vaccines.
Funding:K139165, TKP2021-EGA-29, TKP2021-EGA-24VEKOP-2.3.2-16-2016-00002, VEKOP-2.3.3-15-2016-00006, EFOP-3.6.3-VEKOP-16-2017-00009BO/00898/22, EKÖP-2024-64, NASE