β-Arrestin1/2 are essential for embryonic lymphatic vessel development.

Area of Science:

• Molecular and Cellular Biology
• Developmental Biology
• Vascular Biology

Background:

• Beta-arrestins (β-arrestin1 and β-arrestin2) are key adaptor proteins regulating cellular signaling pathways.
• Their role in embryonic lymphatic vessel development and survival remains largely unexplored.

Purpose of the Study:

• To investigate the function of β-arrestin1 and β-arrestin2 in embryonic lymphatic development and survival.
• To elucidate the molecular mechanisms underlying β-arrestin-mediated regulation of lymphatic endothelial cells.

Main Methods:

• Generation and characterization of mice with lymphatic-specific, tamoxifen-inducible loss of β-arrestin1 and β-arrestin2 (Arrb1/2ΔiLEC).
• In vitro knockdown studies in primary lymphatic endothelial cells (LECs) and human LECs.
• Analysis of embryonic phenotypes, cell proliferation, signaling pathways (AKT, ERK, CREB), and cell-cell junction integrity (VE-Cadherin, β-catenin).

Main Results:

• Arrb1/2ΔiLEC embryos exhibited hydrops fetalis, increased embryonic mortality, growth restriction, and reduced LEC proliferation.
• β-arrestin1 knockdown increased LEC proliferation and AKT activation, while β-arrestin2 knockdown decreased proliferation and ERK/CREB activation.
• Loss of β-arrestins disrupted VE-Cadherin adherens junctions, decreasing membrane localization of VE-Cadherin and β-catenin, and preventing adrenomedullin-induced VE-cadherin linearization.

Conclusions:

• β-arrestin1 and β-arrestin2 are essential for embryonic lymphatic development and survival.
• Their absence leads to hydrops fetalis and embryonic lethality due to impaired LEC proliferation and disrupted endothelial cell-cell junctions.
• These findings highlight β-arrestins as critical regulators of lymphatic vascular integrity.