Caspase-8 modulates physiological and pathological angiogenesis during retina development
Nathalie Tisch, … , Hellmut G. Augustin, Carmen Ruiz de Almodovar
Nathalie Tisch, … , Hellmut G. Augustin, Carmen Ruiz de Almodovar
Published December 2, 2019; First published August 27, 2019
Citation Information: J Clin Invest. 2019;129(12):5092-5107. https://doi.org/10.1172/JCI122767.
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Categories: Research Article Angiogenesis

Caspase-8 modulates physiological and pathological angiogenesis during retina development

Abstract

During developmental angiogenesis, blood vessels grow and remodel to ultimately build a hierarchical vascular network. Whether, how, cell death signaling molecules contribute to blood vessel formation is still not well understood. Caspase-8 (Casp-8), a key protease in the extrinsic cell death–signaling pathway, regulates cell death via both apoptosis and necroptosis. Here, we show that expression of Casp-8 in endothelial cells (ECs) is required for proper postnatal retina angiogenesis. EC-specific Casp-8–KO pups (Casp-8ECKO) showed reduced retina angiogenesis, as the loss of Casp-8 reduced EC proliferation, sprouting, and migration independently of its cell death function. Instead, the loss of Casp-8 caused hyperactivation of p38 MAPK downstream of receptor-interacting serine/threonine protein kinase 3 (RIPK3) and destabilization of vascular endothelial cadherin (VE-cadherin) at EC junctions. In a mouse model of oxygen-induced retinopathy (OIR) resembling retinopathy of prematurity (ROP), loss of Casp-8 in ECs was beneficial, as pathological neovascularization was reduced in Casp-8ECKO pups. Taking these data together, we show that Casp-8 acts in a cell death–independent manner in ECs to regulate the formation of the retina vasculature and that Casp-8 in ECs is mechanistically involved in the pathophysiology of ROP.

Authors

Nathalie Tisch, Aida Freire-Valls, Rosario Yerbes, Isidora Paredes, Silvia La Porta, Xiaohong Wang, Rosa Martín-Pérez, Laura Castro, Wendy Wei-Lynn Wong, Leigh Coultas, Boris Strilic, Hermann-Josef Gröne, Thomas Hielscher, Carolin Mogler, Ralf H. Adams, Peter Heiduschka, Lena Claesson-Welsh, Massimiliano Mazzone, Abelardo López-Rivas, Thomas Schmidt, Hellmut G. Augustin, Carmen Ruiz de Almodovar

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Figure 6

Loss of Casp-8 results in basal activation of p38 MAPK, VE-cadherin instability, and defects in angiogenesis in vitro.

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Loss of Casp-8 results in basal activation of p38 MAPK, VE-cadherin inst...
(A)Western blots showing increased p-p38 under basal conditions in Casp-8KD (shCasp-8) ECs compared with control. (B) Quantification of p-p38 as in A. n = 5. (C) Quantification of p-p38 of HUVECs treated with ZIETD (10 μM, 16 hours) under basal conditions, showing that blocking Casp-8 activity also induces increased basal p-p38. n = 3. (D) Images of VE-cadherin staining in shCtrl and shCasp-8–infected HUVECs treated with or without p38 inhibitor (SB203580, 1 μM, 16 hours). Yellow arrows point to empty VE-cadherin spots. (E) Quantification of VE-cadherin average patch length from cells as in H. (F) Quantification of the total amount of VE-cadherin per cell perimeter reveals that inhibition of p38 (SB203580) in Casp-8KD ECs restores VE-cadherin to control levels. At least 15 cells per condition were quantified. n = 3. (G) Quantification of total tube length of HUVECs treated as in E showing that blocking p38 in Casp-8KD ECs restores VEGF-induced tube formation. 3 fields per condition were quantified. n = 4. (H) Quantitative analysis of total sprout length showing that inhibition of p38 rescues VEGF-induced EC sprouting in Casp-8KD ECs. Approximately 20 beads per condition were quantified. n = 3. For B, C, and E–H, data represent mean ± SEM. *P < 0.05, 1-sample t test (B and C); *P < 0.05; **P < 0.01; ***P < 0.001, 2-way ANOVA with Bonferroni’s multiple comparisons test (E–H). Scale bars: 20 μm (D).