Piezo1 incorporates mechanical force signals into the genetic program that governs lymphatic valve development and maintenance
Dongwon Choi, … , Il-Taeg Cho, Young-Kwon Hong
Dongwon Choi, … , Il-Taeg Cho, Young-Kwon Hong
Published January 24, 2019
Citation Information: JCI Insight. 2019;4(5):e125068. https://doi.org/10.1172/jci.insight.125068.
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Research Article Vascular biology

Piezo1 incorporates mechanical force signals into the genetic program that governs lymphatic valve development and maintenance

Abstract

The lymphatic system plays crucial roles in tissue homeostasis, lipid absorption, and immune cell trafficking. Although lymphatic valves ensure unidirectional lymph flows, the flow itself controls lymphatic valve formation. Here, we demonstrate that a mechanically activated ion channel Piezo1 senses oscillating shear stress (OSS) and incorporates the signal into the genetic program controlling lymphatic valve development and maintenance. Time-controlled deletion of Piezo1 using a pan-endothelial Cre driver (Cdh5[PAC]-CreERT2) or lymphatic-specific Cre driver (Prox1-CreERT2) equally inhibited lymphatic valve formation in newborn mice. Furthermore, Piezo1 deletion in adult lymphatics caused substantial lymphatic valve degeneration. Piezo1 knockdown in cultured lymphatic endothelial cells (LECs) largely abrogated the OSS-induced upregulation of the lymphatic valve signature genes. Conversely, ectopic Piezo1 overexpression upregulated the lymphatic valve genes in the absence of OSS. Remarkably, activation of Piezo1 using chemical agonist Yoda1 not only accelerated lymphatic valve formation in animals, but also triggered upregulation of some lymphatic valve genes in cultured LECs without exposure to OSS. In summary, our studies together demonstrate that Piezo1 is the force sensor in the mechanotransduction pathway controlling lymphatic valve development and maintenance, and Piezo1 activation is a potentially novel therapeutic strategy for congenital and surgery-associated lymphedema.

Authors

Dongwon Choi, Eunkyung Park, Eunson Jung, Boksik Cha, Somin Lee, James Yu, Paul M. Kim, Sunju Lee, Yeo Jin Hong, Chester J. Koh, Chang-Won Cho, Yifan Wu, Noo Li Jeon, Alex K. Wong, Laura Shin, S. Ram Kumar, Ivan Bermejo-Moreno, R. Sathish Srinivasan, Il-Taeg Cho, Young-Kwon Hong

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Figure 1

Piezo1 is essential for lymphatic valve development.

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Piezo1 is essential for lymphatic valve development. (A–S) Effect of lym...
(A–S) Effect of lymphatic deletion of Piezo1 on lymphatic valve development. (A) Experimental design. Control pups (CTR) harbor Prox1-tdTomato and Prox1-CreERT2, but lack the Piezo1fl/fl allele, while lymphatic Piezo1-KO pups (Piezo1ΔLEC) have all Prox1-tdTomato, Prox1-CreERT2, and Piezo1fl/fl. Tamoxifen (75 mg/kg) was s.c. injected into pups at P1, and tissues were harvested and analyzed at P7. (B–I) Mesenteric lymphatics in the (B–E) jejunum or (F–I) colon are shown in the (B, D, F, and H) CTR or (C, E, G, and I) lymphatic Piezo1-KO pups. High-magnification images of mesenteric lymphatic valves of (J and K) CTR and (L and M) Piezo1-KO pups are also shown. (N–Q) Dermal lymphatic valve development was impaired in the tail skin of the lymphatic Piezo1-KO pups. (R and S) Box-and-whisker plots showing lymphatic valve number (R) per lymphatic vessel length or (S) per branching point in the jejunum, colon, and tail. The box plots depict the minimum and maximum values (whiskers), the upper and lower quartiles, and the median. The length of the box represents the interquartile range. (T–V) Impact of endothelial deletion of Piezo1 using a Cdh5(PAC)-CreERT2 driver of lymphatic valve development. (T) Experimental design: Peizo1 deletion was induced in pups [Prox1-tdTomato, Cdh5(PAC)-CreERT2, and/or Piezo1fl/fl] at P3 by i.p. tamoxifen injection (75 mg/kg), and the mesenteric lymphatic valves in the jejunum were analyzed at P10. (U and V) Endothelial Piezo1 deletion significantly inhibited lymphatic valve formation. All images of lymphatic vessels and valves were captured based on the tdTomato signal and shown in inverted grayscales. Boxed areas were enlarged in panels below, respectively. Arrows mark matured Prox1hi lymphatic valves. Scale bars: 1 mm (B, C, F, and G); 500 μm (D, E, H, and I); 50 μm (J–M); 200 μm (N–Q); and 100 μm (U and V). ***P < 0.001, unpaired, 2-tailed t test compared with the valve of the controls. More than 5 pups were used for each group. A representative of >10 images was chosen for each panel.