Targeting KIT prevents brain arteriovenous malformations driven by ALK1-deficient angiogenic endothelial cells
Elise Drapé, Lauranne Carrier, Gael Cagnone, Atik Rohmana Maftuhatul Fuad, Mathilde Bizou, Damian Sanchez, Typhaine Anquetil, Jack Wang, Halima Drissi Touzani Walali, Adnan Gopinadhan, Patrick Piet van Vliet, Joel P. Howard, Mysha Ibnat, Gregor Andelfinger, Ethan Winkler, Bruno Larrivée, Alexandre Dubrac
Elise Drapé, Lauranne Carrier, Gael Cagnone, Atik Rohmana Maftuhatul Fuad, Mathilde Bizou, Damian Sanchez, Typhaine Anquetil, Jack Wang, Halima Drissi Touzani Walali, Adnan Gopinadhan, Patrick Piet van Vliet, Joel P. Howard, Mysha Ibnat, Gregor Andelfinger, Ethan Winkler, Bruno Larrivée, Alexandre Dubrac
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Research Article Cell biology Vascular biology

Targeting KIT prevents brain arteriovenous malformations driven by ALK1-deficient angiogenic endothelial cells

Abstract

Hereditary hemorrhagic telangiectasia type 2 (HHT2), caused by mutations in ACVRL1 (also known as ALK1), is characterized by brain arteriovenous malformations (bAVMs), abnormal artery–vein connections for which treatment options remain limited. Despite evidence of endothelial cell (EC) heterogeneity, its role in bAVM pathogenesis remains poorly defined. Using EC-specific inducible Alk1-knockout mice (Alk1iECKO) and regionally resolved single-cell RNA sequencing, we showed that loss of ALK1 signaling induces bAVMs predominantly in the perineural vascular plexus. This process is driven by the emergence of a KIT+ angiogenic EC population with human AVM-like transcriptional features, including tip cell markers and activation of PI3K and KRAS signaling pathways. Cross-species analyses and validation in human samples demonstrated that KIT expression is conserved in ECs from both sporadic and HHT2 bAVMs. Drug-repurposing analysis identified KIT as a top actionable target, and we showed that Kit is directly repressed by BMP9/ALK1/SMAD4 signaling. Pharmacological inhibition of KIT reduced angiogenic reprogramming and vascular malformations in vivo without affecting normal vasculature. These findings identify a pathogenic angiogenic EC state and position KIT signaling as a therapeutically actionable pathway in bAVMs.

Authors

Elise Drapé, Lauranne Carrier, Gael Cagnone, Atik Rohmana Maftuhatul Fuad, Mathilde Bizou, Damian Sanchez, Typhaine Anquetil, Jack Wang, Halima Drissi Touzani Walali, Adnan Gopinadhan, Patrick Piet van Vliet, Joel P. Howard, Mysha Ibnat, Gregor Andelfinger, Ethan Winkler, Bruno Larrivée, Alexandre Dubrac

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Figure 6

Pharmacological KIT inhibition prevents EC proliferation and brain vascular malformations in Alk1iECKO mice.

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Pharmacological KIT inhibition prevents EC proliferation and brain vascu...
(A) Experimental timeline of tamoxifen and KIT inhibitor administration in Alk1iECKO and control mice. (B) CD31 immunostaining of the PNVP of P8 Alk1iECKO mice injected with KIT-blocking antibody or control (CT). (C and D) Vascular area (C) and vessel diameter (D) quantifications in the PNVP of P8 Alk1iECKO mice (n = 5). (E) EdU incorporation and ERG123 immunostaining in the PNVP of control and KIT-blocking antibody–treated Alk1iECKO mice. (F) EdU+/ERG+ EC quantification in control (n = 4) and KIT-blocking antibody– (n = 6) treated Alk1iECKO mice. (G) Survival curve of Alk1iECKO mice treated with KIT-blocking antibody (n = 6) or control (n = 4). (H) Heatmap showing scaled gene expression of angiogenic markers assessed by RNA-seq in mouse brain endothelial cells (mBECs) from Alk1iECKO and control mice treated with KIT-blocking antibody or control (n = 3). (I) RNAscope detection of Stc1 mRNA with CD31 immunostaining in the PNVP of Alk1iECKO mice treated with KIT-blocking antibody or control. (J) Drug-repurposing analysis applied to the Alk1iECKO angiogenic 2 EC cluster. Left: Network-based inhibition weight of angiogenic 2 cluster compared with all control EC clusters. Right: Top candidate drugs ranked by predicted drug score. (K) CD31 immunostaining of the PNVP of P8 Alk1iECKO mice injected with imatinib or control. (L) Vascular area quantification in the PNVP of P8 Alk1iECKO mice treated with imatinib (n = 8) or control (n = 10). (M) Vessel diameter quantification in the PNVP of P8 Alk1iECKO mice treated with imatinib (n = 8) or control (n = 10). (N) Survival curve of Alk1iECKO mice treated with imatinib or control. Data represent means ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001. Unpaired t test (C, D, L, and M), Welch’s t test (M), ordinary 1-way ANOVA (F), and limma-voom moderated t test (H) were performed. Each dot represents 1 mouse. For survival curves Kaplan-Meier methods were performed, using log-rank test. For the heatmap batch-corrected limma-voom test was performed, and non-significant values correspond to comparison between Alk1iECKO KIT-blocking antibody vs. CT mice.