Cooperative ETS transcription factors are required for lymphatic endothelial cell integrity and resilience
Myung Jin Yang, Seok Kang, Seon Pyo Hong, Hokyung Jin, Jin-Hui Yoon, Cheolhwa Jin, Chae Min Yuk, Lydia Getachew Gebeyehu, Junho Jung, Sung-Hwan Yoon, Hyuek Jong Lee, Gou Young Koh
Myung Jin Yang, Seok Kang, Seon Pyo Hong, Hokyung Jin, Jin-Hui Yoon, Cheolhwa Jin, Chae Min Yuk, Lydia Getachew Gebeyehu, Junho Jung, Sung-Hwan Yoon, Hyuek Jong Lee, Gou Young Koh
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Research Article Cell biology Development Vascular biology

Cooperative ETS transcription factors are required for lymphatic endothelial cell integrity and resilience

Abstract

Lymphatics maintain fluid homeostasis, immune surveillance, and tissue integrity. Here, we identified the E26 transformation-specific transcription factors Erg and Fli1 as essential cooperative regulators of lymphatic integrity and function. Using inducible lymphatic endothelial cell–specific deletion in mice, we demonstrated that combined loss of Erg and Fli1 in adults results in fatal lymphatic failure, including chylothorax, chylous ascites, and impaired lymphatic drainage. Single-cell transcriptomic analysis revealed that loss of Erg and Fli1 causes disrupted lymphatic heterogeneity and dysregulation of key lymphatic genes, including valve-specific gene profiles. Erg and Fli1 coordinated lymphatic-immune crosstalk by transcriptionally regulating C-C motif chemokine ligand 21, which mediates DC trafficking. Erg or Fli1 loss also induced proinflammatory and prothrombotic gene expression, further contributing to lymphatic dysfunction. During embryonic development, the codeletion led to lymphatic mispatterning and loss of valve-initiating lymphatic endothelial cell clusters. The impact of loss of Erg and Fli1 function on lymphatic development in mice is consistent with FOXC2 mutations in lymphedema-distichiasis syndrome or ERG gene variants underlying primary lymphedema in humans. Moreover, Erg and Fli1 were required for regenerative lymphangiogenesis and lymphatic repair following injury in adults. Our findings establish Erg and Fli1 as core transcriptional regulators of lymphatic identity, integrity, and function.

Authors

Myung Jin Yang, Seok Kang, Seon Pyo Hong, Hokyung Jin, Jin-Hui Yoon, Cheolhwa Jin, Chae Min Yuk, Lydia Getachew Gebeyehu, Junho Jung, Sung-Hwan Yoon, Hyuek Jong Lee, Gou Young Koh

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Figure 9

Dual deletion of Erg and Fli1 attenuates regenerative lymphangiogenesis.

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Dual deletion of Erg and Fli1 attenuates regenerative lymphangiogenesis....
(A) Diagram depicting ear punch injury-induced lymphangiogenesis model, schedules for daily administrations of tamoxifen (Tmx) and ear punch injury, and sampling 2 weeks later. (B) Representative images of Prox1+/Lyve1+ dermal lymphatics after the ear punch injury in PG-WT and PG-Erg/Fli1iΔLEC mice. White dashed lines indicate the injury margin, yellow dashed boxes are magnified in right panels, and white arrowheads indicate lymphatic sprouts. Similar findings were observed from n = 5 mice/group from 2 independent experiments. Scale bars: 200 μm. (C) Comparison of number of lymphatic sprouts and Lyve1+ lymphatic density in PG-WT and PG-Erg/Fli1iΔLEC mice after the ear punch injury. Each dot indicates a value from 1 mouse, and n = 5 mice/group from 2 independent experiments. Data are shown as the mean ± SD; P value versus WT by 2-tailed Mann-Whitney U test. (D) Schematic diagram depicting i.p. administrations of Tmx, generation of tail or leg secondary lymphedema model, and analyses after 2 weeks of injury. (E) Representative images of mouse tails after 15 days of injury in WT or Erg/Fli1iΔLEC mice. Similar findings were observed from n = 5 mice/group from 2 independent experiments. Scale bars: 1 cm. (F) Representative images of mouse hind paws after 15 days of injury in WT or Erg/Fli1iΔLEC mice. Similar findings were observed from n = 3 mice/group from 2 independent experiments. Scale bars: 2 mm. (G and H) Comparison of tail diameter and footpad thickness in WT and Erg/Fli1iΔLEC mice after tail/leg injury models. Each dot indicates a value from 1 mouse, and n = 3–5 mice/group from 2 independent experiments. Data are shown as the mean ± SD; P value versus WT by 2-way ANOVA followed by Šidák’s post hoc test.