ABSTRACT
Lymphatic vessels grow through active sprouting and mature into a vascular complex that includes lymphatic capillaries and collecting vessels that ensure fluid transport. However, the signaling cues that direct lymphatic sprouting and patterning remain unclear. In this study, we demonstrate that chemokine signaling, specifically through CXCL12 and CXCR4, plays crucial roles in regulating lymphatic development. We show that LEC-specific Cxcr4-deficient mouse embryos and CXCL12 mutant embryos exhibit severe defects in lymphatic sprouting, migration and lymphatic valve formation. We also discovered that CXCL12, originating from peripheral nerves, directs the migration of dermal lymphatic vessels to align with nerves in developing skin. Deletion of Cxcr4 or blockage of CXCL12 and CXCR4 activity results in reduced VEGFR3 levels on the LEC surface. This, in turn, impairs VEGFC-mediated VEGFR3 signaling and downstream PI3K and AKT activities. Taken together, these data identify previously unknown chemokine signaling originating from peripheral nerves that guides dermal lymphatic sprouting and patterning. Our work identifies for the first time a neuro-lymphatics communication during mouse development and reveals a previously unreported mechanism by which CXCR4 modulates VEGFC, VEGFR3 and AKT signaling.
Footnotes
Author contributions
Conceptualization: L.N.H.D., S.M., H.C., M.V.A., X.L.; Methodology: L.N.H.D., E.D., C.G.L., M.B., A.M.P., S.K., Y.H., M.O., X.L.; Software: L.N.H.D.; Validation: L.N.H.D.; Formal analysis: L.N.H.D.; Investigation: L.N.H.D., C.G.L., M.B., S.K., X.L.; Resources: L.N.H.D., S.K., X.L.; Data curation: L.N.H.D., X.L.; Writing - original draft: L.N.H.D., X.L.; Writing - review & editing: L.N.H.D., E.D., C.G.L., M.B., A.M.P., Y.H., M.O., S.M., H.C., M.V.A., S.K., X.L.; Visualization: X.L.; Supervision: X.L.; Project administration: X.L.; Funding acquisition: S.M., H.C., M.V.A., X.L.
Funding
This work was supported by the National Institutes of Health (R01HL163269 to X.L.; R01HL141108 and R01HL117724 to M.V.A.; R01HL133216, R01HL130845 and R01HL141858 to H.C.; R01HL137850 to S.M.; R01NS133694 to S.K.), by a Institutional National Research Service Award T32 training grant (T32HL091804 to E.D.) and by a W. W. Smith Charitable Trust Award (H2204 to X.L.). Deposited in PMC for release after 12 months.
Data availability
All relevant data can be found within the article and its supplementary information.
