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A dural lymphatic vascular system that drains brain interstitial fluid and macromolecules.

Aspelund A, Antila S, Proulx ST, Karlsen TV, Karaman S, Detmar M, Wiig H, Alitalo K - J. Exp. Med. (2015)

Bottom Line: Surprisingly, brain ISF pressure and water content were unaffected.Overall, these findings indicate that the mechanism of CSF flow into the dcLNs is directly via an adjacent dural lymphatic network, which may be important for the clearance of macromolecules from the brain.Importantly, these results call for a reexamination of the role of the lymphatic system in CNS physiology and disease.

View Article: PubMed Central - HTML - PubMed

Affiliation: Wihuri Research Institute and Translational Cancer Biology Program, Biomedicum Helsinki, University of Helsinki, 00014 Helsinki, Finland Wihuri Research Institute and Translational Cancer Biology Program, Biomedicum Helsinki, University of Helsinki, 00014 Helsinki, Finland.

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Absence of dural lymphatic vasculature in K14-VEGFR3-Ig TG mice. (A–F) Analysis of dura mater lymphatic vasculature in K14-VEGFR3-Ig TG and WT littermate control mice. (A–C) Immunofluorescence of the superior sagittal lymphatic vessels (arrowheads) for PECAM1, PROX1, and CCL21 (A and B) and quantification of PROX1+/CCL21+ lymphatic ECs (LECs)/grid (C). (D–F) Immunofluorescence of the pterygopalatine and middle meningeal lymphatic vessels (arrowheads) for PECAM1 and PROX1 (D and E) and quantification of PROX1+ LECs/grid (F). (G–I) Stereomicroscopic photographs showing the absence of the scLNs (arrows) in the TG mice (G and H) and quantification of the (mean left/right) scLN and dcLN surface areas (I). Micrographs of the dcLNs are shown in Fig. 4 C. (A–F) n = 3 (TG) and 4 (WT). (G and H) n = 4/group. Data are representative of two independent experiments. Bars: (A, B, D, and E) 100 µm; (G and H) 2 mm. Error bars indicate SD. Statistical analysis: two-tailed Student’s t test (C and F) and two-way ANOVA followed by Šídák’s post-hoc test (I). ***, P < 0.001; ****, P < 0.0001.
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fig3: Absence of dural lymphatic vasculature in K14-VEGFR3-Ig TG mice. (A–F) Analysis of dura mater lymphatic vasculature in K14-VEGFR3-Ig TG and WT littermate control mice. (A–C) Immunofluorescence of the superior sagittal lymphatic vessels (arrowheads) for PECAM1, PROX1, and CCL21 (A and B) and quantification of PROX1+/CCL21+ lymphatic ECs (LECs)/grid (C). (D–F) Immunofluorescence of the pterygopalatine and middle meningeal lymphatic vessels (arrowheads) for PECAM1 and PROX1 (D and E) and quantification of PROX1+ LECs/grid (F). (G–I) Stereomicroscopic photographs showing the absence of the scLNs (arrows) in the TG mice (G and H) and quantification of the (mean left/right) scLN and dcLN surface areas (I). Micrographs of the dcLNs are shown in Fig. 4 C. (A–F) n = 3 (TG) and 4 (WT). (G and H) n = 4/group. Data are representative of two independent experiments. Bars: (A, B, D, and E) 100 µm; (G and H) 2 mm. Error bars indicate SD. Statistical analysis: two-tailed Student’s t test (C and F) and two-way ANOVA followed by Šídák’s post-hoc test (I). ***, P < 0.001; ****, P < 0.0001.

Mentions: VEGF-C/D signaling via VEGFR3 is a critical regulator of lymphangiogenesis (Secker and Harvey, 2015). To (a) study whether dura mater lymphatic vessels are regulated by VEGFC/D–VEGFR3 signaling and (b) characterize an animal model in which the functional consequences of dura mater lymphatic vessel aplasia can be examined, we investigated the K14-VEGFR3-Ig transgenic (TG) mouse, which has impaired VEGF-C/D–VEGFR3 signaling. These mice express a soluble VEGF-C/D trap protein consisting of the ligand-binding Ig homology domains 1–3 of VEGFR3 fused with the Fc domain of Igγ (Mäkinen et al., 2001). Although the VEGF-C/D trap transgene is expressed in keratinocytes, the circulating protein inhibits lymphangiogenesis in most tissues, and the mice display LN hypoplasia (Mäkinen et al., 2001; Alitalo et al., 2013). Lymphatic vessels were absent from both superior and basal parts of the skull in the TG mice compared with WT littermate mice (Fig. 3, A–F). Surprisingly, the mice displayed absence of only the scLNs but not dcLNs (Fig. 3, G–I; and Fig. 4 C). These data indicate that the dura mater lymphatic vessels are very sensitive to the inhibition of VEGF-C/D signaling and that the K14-VEGFR3-Ig TG mouse is a suitable model for studying the functional consequences of the absence of lymphatic drainage from the brain.


A dural lymphatic vascular system that drains brain interstitial fluid and macromolecules.

Aspelund A, Antila S, Proulx ST, Karlsen TV, Karaman S, Detmar M, Wiig H, Alitalo K - J. Exp. Med. (2015)

Absence of dural lymphatic vasculature in K14-VEGFR3-Ig TG mice. (A–F) Analysis of dura mater lymphatic vasculature in K14-VEGFR3-Ig TG and WT littermate control mice. (A–C) Immunofluorescence of the superior sagittal lymphatic vessels (arrowheads) for PECAM1, PROX1, and CCL21 (A and B) and quantification of PROX1+/CCL21+ lymphatic ECs (LECs)/grid (C). (D–F) Immunofluorescence of the pterygopalatine and middle meningeal lymphatic vessels (arrowheads) for PECAM1 and PROX1 (D and E) and quantification of PROX1+ LECs/grid (F). (G–I) Stereomicroscopic photographs showing the absence of the scLNs (arrows) in the TG mice (G and H) and quantification of the (mean left/right) scLN and dcLN surface areas (I). Micrographs of the dcLNs are shown in Fig. 4 C. (A–F) n = 3 (TG) and 4 (WT). (G and H) n = 4/group. Data are representative of two independent experiments. Bars: (A, B, D, and E) 100 µm; (G and H) 2 mm. Error bars indicate SD. Statistical analysis: two-tailed Student’s t test (C and F) and two-way ANOVA followed by Šídák’s post-hoc test (I). ***, P < 0.001; ****, P < 0.0001.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4493418&req=5

fig3: Absence of dural lymphatic vasculature in K14-VEGFR3-Ig TG mice. (A–F) Analysis of dura mater lymphatic vasculature in K14-VEGFR3-Ig TG and WT littermate control mice. (A–C) Immunofluorescence of the superior sagittal lymphatic vessels (arrowheads) for PECAM1, PROX1, and CCL21 (A and B) and quantification of PROX1+/CCL21+ lymphatic ECs (LECs)/grid (C). (D–F) Immunofluorescence of the pterygopalatine and middle meningeal lymphatic vessels (arrowheads) for PECAM1 and PROX1 (D and E) and quantification of PROX1+ LECs/grid (F). (G–I) Stereomicroscopic photographs showing the absence of the scLNs (arrows) in the TG mice (G and H) and quantification of the (mean left/right) scLN and dcLN surface areas (I). Micrographs of the dcLNs are shown in Fig. 4 C. (A–F) n = 3 (TG) and 4 (WT). (G and H) n = 4/group. Data are representative of two independent experiments. Bars: (A, B, D, and E) 100 µm; (G and H) 2 mm. Error bars indicate SD. Statistical analysis: two-tailed Student’s t test (C and F) and two-way ANOVA followed by Šídák’s post-hoc test (I). ***, P < 0.001; ****, P < 0.0001.
Mentions: VEGF-C/D signaling via VEGFR3 is a critical regulator of lymphangiogenesis (Secker and Harvey, 2015). To (a) study whether dura mater lymphatic vessels are regulated by VEGFC/D–VEGFR3 signaling and (b) characterize an animal model in which the functional consequences of dura mater lymphatic vessel aplasia can be examined, we investigated the K14-VEGFR3-Ig transgenic (TG) mouse, which has impaired VEGF-C/D–VEGFR3 signaling. These mice express a soluble VEGF-C/D trap protein consisting of the ligand-binding Ig homology domains 1–3 of VEGFR3 fused with the Fc domain of Igγ (Mäkinen et al., 2001). Although the VEGF-C/D trap transgene is expressed in keratinocytes, the circulating protein inhibits lymphangiogenesis in most tissues, and the mice display LN hypoplasia (Mäkinen et al., 2001; Alitalo et al., 2013). Lymphatic vessels were absent from both superior and basal parts of the skull in the TG mice compared with WT littermate mice (Fig. 3, A–F). Surprisingly, the mice displayed absence of only the scLNs but not dcLNs (Fig. 3, G–I; and Fig. 4 C). These data indicate that the dura mater lymphatic vessels are very sensitive to the inhibition of VEGF-C/D signaling and that the K14-VEGFR3-Ig TG mouse is a suitable model for studying the functional consequences of the absence of lymphatic drainage from the brain.

Bottom Line: Surprisingly, brain ISF pressure and water content were unaffected.Overall, these findings indicate that the mechanism of CSF flow into the dcLNs is directly via an adjacent dural lymphatic network, which may be important for the clearance of macromolecules from the brain.Importantly, these results call for a reexamination of the role of the lymphatic system in CNS physiology and disease.

View Article: PubMed Central - HTML - PubMed

Affiliation: Wihuri Research Institute and Translational Cancer Biology Program, Biomedicum Helsinki, University of Helsinki, 00014 Helsinki, Finland Wihuri Research Institute and Translational Cancer Biology Program, Biomedicum Helsinki, University of Helsinki, 00014 Helsinki, Finland.

Show MeSH
Related in: MedlinePlus