Fig. 6. Administration of VEGFC mRNA-LNPs stimulates active lymphatic function.
a Monitoring active lymphatic function in the ears of Prox1GFP mice after intradermal injection of 1 µg of Poly(C) or VEGFC mRNA-LNPs. Twenty-two days after treatment, 70 kDa Rhodamine dextran (Rh-D) was injected into the ear and the transport of the molecule was monitored by fluorescent microscopy 60 min post Rh-D administration. Representative images are shown of 10 injected mouse ears per group (bars, 1000 µm). Arrows indicate Prox1-GFP positive and Rh-D positive lymphatic vessels. b Monitoring active lymphatic function in the paws of mice after intradermal injection of 1 µg of Poly(C) or VEGFC mRNA-LNPs. Seventy-five days after treatment, 70 kDa Rh-D was injected into the paws and the transport of the molecule was monitored by fluorescent microscopy 90 min post Rh-D administration. Representative images are shown of 2 mouse hind limbs in each group (bars, 1000 µm). Green rectangles show the magnified area which represent the area of popliteal lymph nodes. c Analysis of lymphatic morphology in the ear of mice injected with 1 µg of Poly(C) or VEGFC mRNA-LNPs. Representative images 22 days after the treatment of 3 mouse ears per group are shown by anti-LYVE1 and anti-α-SMA immunostaining of slides processed by paraffin-based histology (bars, 50 µm). Arrows indicate LYVE1 low lymphatics surrounded by α-SMA positive cells. d–e Assessment of lymphatic proliferation 5 days after intradermal injection with 1 µg of Poly(C) or VEGFC mRNA-LNPs. Representative images of 3 mouse ears are shown in each group with EdU staining and anti-α-SMA immunostaining of slides processed by paraffin-based histology (bars, 50 µm) and shown by widefield (d) and confocal imaging (e). Arrows indicate EdU positive cells surrounded by α-SMA positive cells. All cell nuclei are labeled with DAPI (blue) in paraffin-embedded tissues.