β-arrestin1/2 are essential for embryonic lymphatic vessel development

Abstract

Lymphatic dysfunction can lead to fetal loss due to interstitial edema known as hydrops fetalis during development and lymphedema in adulthood. Lymphedema affects an estimated 250 million individuals worldwide, yet there is no effective treatment available. Numerous studies have established G protein-coupled receptors (GPCRs) as key lymphangiogenic signaling pathways and ideal druggable therapeutical targets. β-arrestins (β-arrestin 1 and 2) are ubiquitously expressed cytosolic adaptor proteins which perform a wide range of functions in GPCR pathways, such as promoting agonist-induced internalization and forming signaling scaffolds with internalized GPCRs in endosomes. However, the roles of β-arrestins in lymphatic vessel development and function remain undefined. We hypothesize that β-arrestin1/2 are essential in embryonic lymphatic vessel development. To test this hypothesis, I used an inducible β-arrestin1fl/fl (Arrb1 fl/fl), β-arrestin2fl/fl (Arrb2 fl/fl);Prox1 CreERT2 mouse line. β-arrestin1 and 2 were deleted by oral gavage of tamoxifen at embryonic day 10.5 (E10.5) and E12.5, critical points for developmental lymphangiogenesis. Compared to Arrb1/2fl/flembryos, the Arrb1/2fl/fl;Prox1CreERT2 embryos exhibit profound hydrops fetalis, subcutaneous hemorrhages, and increased embryonic lethality between E14.5 and E16.5. At E15.5, the Arrb1/2fl/fl;Prox1CreERT2 embryos with edema show decreased weight indicating growth restriction compared to controls. Jugular lymphatic sacs are enlarged and filled with blood in Arrb1/2fl/fl;Prox1CreERT2 embryos compared to controls. Dermal lymphatic vessel length in the Arrb1/2fl/fl;Prox1CreERT2 embryos is shorter than controls. Collectively, our results demonstrate that loss of β-arrestin1/2 expression in lymphatics causes mid-gestational arrest in lymphatic development and fetal growth restriction, indicating that β-arrestins are required for developmental lymphangiogenesis in mammals. American Physiological Society postdoctoral Fellowship (to YT) and NIH R01 HL129086 (to KMC). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.