Immune-interacting lymphatic endothelial subtype at capillary terminals drives lymphatic malformation.

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Petkova M, Kraft M, Stritt S, Martinez-Corral I, Ortsäter H, Vanlandewijck M, Jakic B, Baselga E, Castillo SD, Graupera M, Betsholtz C, Mäkinen T

J. Exp. Med. 220 (4) - [2023-04-03; online 2023-01-23]

Oncogenic mutations in PIK3CA, encoding p110α-PI3K, are a common cause of venous and lymphatic malformations. Vessel type-specific disease pathogenesis is poorly understood, hampering development of efficient therapies. Here, we reveal a new immune-interacting subtype of Ptx3-positive dermal lymphatic capillary endothelial cells (iLECs) that recruit pro-lymphangiogenic macrophages to promote progressive lymphatic overgrowth. Mouse model of Pik3caH1047R-driven vascular malformations showed that proliferation was induced in both venous and lymphatic ECs but sustained selectively in LECs of advanced lesions. Single-cell transcriptomics identified the iLEC population, residing at lymphatic capillary terminals of normal vasculature, that was expanded in Pik3caH1047R mice. Expression of pro-inflammatory genes, including monocyte/macrophage chemokine Ccl2, in Pik3caH1047R-iLECs was associated with recruitment of VEGF-C-producing macrophages. Macrophage depletion, CCL2 blockade, or anti-inflammatory COX-2 inhibition limited Pik3caH1047R-driven lymphangiogenesis. Thus, targeting the paracrine crosstalk involving iLECs and macrophages provides a new therapeutic opportunity for lymphatic malformations. Identification of iLECs further indicates that peripheral lymphatic vessels not only respond to but also actively orchestrate inflammatory processes.

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PubMed 36688917

DOI 10.1084/jem.20220741

Crossref 10.1084/jem.20220741

pmc: PMC9884640
pii: 213817