Mechanotransduction, PROX1, and FOXC2 Cooperate to Control Connexin37 and Calcineurin during Lymphatic-Valve Formation

Abstract

Lymphatic valves are essential for efficient lymphatic transport, but the mechanisms of early lymphatic-valve morphogenesis and the role of biomechanical forces are not well understood. We found that the transcription factors PROX1 and FOXC2, highly expressed from the onset of valve formation, mediate segregation of lymphatic-valve-forming cells and cell mechanosensory responses to shear stress in vitro. Mechanistically, PROX1, FOXC2, and flow coordinately control expression of the gap junction protein connexin37 and activation of calcineurin/NFAT signaling. Connexin37 and calcineurin are required for the assembly and delimitation of lymphatic valve territory during development and for its postnatal maintenance. We propose a model in which regionally increased levels/activation states of transcription factors cooperate with mechanotransduction to induce a discrete cell-signaling pattern and morphogenetic event, such as formation of lymphatic valves. Our results also provide molecular insights into the role of endothelial cell identity in the regulation of vascular mechanotransduction.

Syndecan 4 controls lymphatic vasculature remodeling during mouse embryonic development

“…In control mice, lymphatic valves start to develop in mesenteric lymphatic vessels at E16.5 (Sabine et al, 2012;Tatin et al, 2013). This is also the time when flow begins (Sabine et al, 2012). In agreement with previous reports (Sabine et al, 2012;Tatin et al, 2013), the development of lymphatic valves in control mice begins by the formation of clusters of Prox1 high lymphatic valve-forming ECs that are initially aligned along the longitudinal axis of lymphatic vessels (Fig.…”

“…Given these remodeling abnormalities, we set out to investigate the development of lymphatic valves, an important event during lymphatic vasculature remodeling. In control mice, lymphatic valves start to develop in mesenteric lymphatic vessels at E16.5 (Sabine et al, 2012;Tatin et al, 2013). This is also the time when flow begins (Sabine et al, 2012).…”

“…The effective unidirectional transport of the lymphatic fluid requires the formation of lymphatic intraluminal valves (hereafter referred to as lymphatic valves) that prevent backflow of lymph. A previous study has established that initiation of lymphatic fluid flow is required for the development of lymphatic valves, a process that involves the transcription factors Prox1 and FoxC2 (Sabine et al, 2012). Flow is also required for lymphatic fate maintenance (Chen et al, 2012), lymphatic collecting vessel maturation (Sweet et al, 2015) and lymphatic vessel stabilization (Sabine et al, 2015).…”

Sphingosine 1-phosphate receptor 1 regulates the directional migration of lymphatic endothelial cells in response to fluid shear stress

“…Lymphatic endothelial cells (LECs), which line lymphatic vessels, experience a wide range in wall shear stress (WSS), ranging from 0 to 12 dynes cm 22 in rat mesenteric prenodal lymphatics [13], and up to 40 dynes cm 22 in models of lymphedema [16]. Interestingly, the physical cue provided by WSS has been proposed to play an essential role in the development of lymphatic valves, which preferentially form at constrictions and vessel junctions, where both geometries feature spatial gradients in WSS [5,11].…”

“…Fluid flow is an important cue in the development and stabilization of the lymphatic system [5,[7][8][9][10][11][12][13][14][15]. Lymphatic endothelial cells (LECs), which line lymphatic vessels, experience a wide range in wall shear stress (WSS), ranging from 0 to 12 dynes cm 22 in rat mesenteric prenodal lymphatics [13], and up to 40 dynes cm 22 in models of lymphedema [16].…”