Extended Data Fig. 7: CSF drainage through the hard palate lymphatic plexus to the submandibular lymph node.

a, Sequence of intracisternal (i.c.) infusion of 1.0 μl TMR-dextran or FluoSpheres over 1 min into Prox1-GFP mice followed by analysis of the distribution of the tracer in the hard palate lymphatic plexus at 60 min. b-d, Fluorescence images showing the distribution of TMR-dextran or FluoSpheres (red) in whole mounts of the hard palate and soft palate of Prox1-GFP mice (b,c). White dashed lines mark border between hard palate and soft palate (b). Tracer fluorescence (red) is strong in hard palate lymphatic plexus (red arrowheads) but not in soft palate lymphatic plexus (b,c white empty arrowheads). Orange arrowheads mark the faint TMR-dextran fluorescence in the nasopharyngeal lymphatic plexus (b). Hard palate lymphatic plexus of Prox1-GFP mouse stained for VEGFR3 (red) and LYVE1 (blue) (d). Lymphatic valves (d, white arrowheads). Initial lymphatics (d, blue arrowheads) are distributed in the medial and lateral sides of hard palate. Scale bars, 1 mm. Representative of n = 5 mice from three independent experiments. e,f, Images showing TMR-dextran fluorescence (red arrowheads) in the buccal (e) and mandibular (f) portions of superficial cervical lymphatic scLV-2 between the hard palate lymphatic plexus and submandibular lymph node. White dashed lines (e) outline border of hard palate, tongue, and buccal portion of scLV-2. Yellow arrows mark the direction of CSF outflow. Scale bars, 1 mm. Representative of n = 5 mice from three independent experiments. g, Drawing of downstream connection of hard palate plexus to submandibular lymph node (smLN) through buccal and mandibular portions of scLV-2 for CSF drainage. Locations of scLV-1 and scLV-3 are shown for comparison. Left (Lt.), Right (Rt.). Anatomical positions are indicated in the bottom left corner: A, anterior; P, posterior; M, medial; L, lateral.