YAP and TAZ Negatively Regulate Prox1 During Developmental and Pathologic Lymphangiogenesis

Circ Res. 2019 Jan 18;124(2):225-242. doi: 10.1161/CIRCRESAHA.118.313707.


Rationale: The Hippo pathway governs cellular differentiation, morphogenesis, and homeostasis, but how it regulates these processes in lymphatic vessels is unknown.

Objective: We aimed to reveal the role of the final effectors of the Hippo pathway, YAP (Yes-associated protein) and TAZ (transcriptional coactivator with PDZ-binding motif), in lymphatic endothelial cell (LEC) differentiation, morphogenesis, and homeostasis.

Methods and results: During mouse embryonic development, LEC-specific depletion of Yap/Taz disturbed both plexus patterning and valve initiation with upregulated Prox1 (prospero homeobox 1). Conversely, LEC-specific YAP/TAZ hyperactivation impaired lymphatic specification and restricted lymphatic sprouting with profoundly downregulated Prox1. Notably, lymphatic YAP/TAZ depletion or hyperactivation aggravated or attenuated pathological lymphangiogenesis in mouse cornea. Mechanistically, VEGF (vascular endothelial growth factor)-C activated canonical Hippo signaling pathway in LECs. Indeed, repression of PROX1 transcription by YAP/TAZ hyperactivation was mediated by recruitment of NuRD (nucleosome remodeling and histone deacetylase) complex and endogenous binding activity of TEAD (TEA domain family members) to the PROX1 promoter. Furthermore, YAP/TAZ hyperactivation enhanced MYC signaling and inhibited CDKN1C, leading to cell cycle dysregulation and aberrant proliferation.

Conclusions: We find that YAP and TAZ play promoting roles in remodeling lymphatic plexus patterning and postnatal lymphatic valve maintenance by negatively regulating Prox1 expression. We further show that YAP and TAZ act as plastic regulators of lymphatic identity and define the Hippo signaling-mediated PROX1 transcriptional programing as a novel dynamic checkpoint underlying LEC plasticity and pathophysiology.

Keywords: developmental biology; endothelial cells; lymphatic vessels; vascular endothelial growth factor C; vascular remodeling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism*
  • Animals
  • Cell Cycle Proteins
  • Cell Differentiation
  • Cell Plasticity
  • Cell Proliferation
  • Cells, Cultured
  • Endothelial Cells / metabolism*
  • Endothelial Cells / pathology
  • Gene Expression Regulation, Developmental
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism*
  • Humans
  • Lymphangiogenesis*
  • Lymphatic Vessels / metabolism*
  • Lymphatic Vessels / pathology
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Morphogenesis
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism*
  • Signal Transduction
  • Trans-Activators
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism*
  • YAP-Signaling Proteins


  • Adaptor Proteins, Signal Transducing
  • Cell Cycle Proteins
  • Homeodomain Proteins
  • Phosphoproteins
  • Trans-Activators
  • Tumor Suppressor Proteins
  • Wwtr1 protein, mouse
  • YAP-Signaling Proteins
  • Yap1 protein, mouse
  • prospero-related homeobox 1 protein