Related Experiment Video
Updated: Jan 7, 2026
In Vitro Three-Dimensional Sprouting Assay of Angiogenesis Using Mouse Embryonic Stem Cells for Vascular Disease Modeling and Drug Testing
Published on: May 11, 2021
Modulating ACVRL1 Expression in HMEC1 Cells as a Simplified In Vitro Model for Hereditary Hemorrhagic Telangiectasia
Johanna R Rusche1, Michael Bette2, Boris A Stuck1
1VASCERN HHT Reference Center and Interdisciplinary Center for Vascular Anomalies, Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Giessen and Marburg, Campus Marburg, and Philipps-Universität Marburg, Marburg, Germany.
Background/Aim:
Hereditary hemorrhagic telangiectasia (HHT) is a rare disease with an incidence of 1:5,000. HHT is inherited in an autosomal dominant manner and is associated with vascular malformations. It particularly affects the genes ENG (HHT1) and ACVRL1 (HHT2). Clinically, patients typically exhibit pronounced recurrent epistaxis. The aim of this study was to evaluate if ACVRL1 knockdown in HMEC-1 endothelial cells could induce a HHT2-like phenotype which could be deployed as a model for HHT2.
Materials And Methods:
The human immortalized endothelial cell line HMEC-1 was used for the experiments. RNAi knockdown was performed using a pool of four siRNAs targeting the ACVRL1 gene. The gene knockdown was verified using RT-qPCR and Western blot analysis. The effects of ACVRL1 knockdown on angiogenesis were compared to a non-target (NT) small RNA control using a tube formation assay. The expression of 84 endothelia-associated genes was analyzed with RT-qPCR.
Results:
Tube formation ability was significantly affected by ACVRL1 knockdown. In particular, the parameters total tube length, total segment length, total master segment length, total branching length, total mesh area and branching interval were significantly increased whereas total isolated branch length, number of master junctions, number of branches and the number of isolated segments decreased after ACVRL1 knockdown. Significant changes in the expression of angiogenesis related genes were detected by qPCR analysis and discussed.
Conclusion:
Knockdown of ACVRL1 in HMEC-1 endothelial cells leads to pathological angiogenesis with enhanced tube formation capacity, which is similar to the angiogenesis in vivo in patients with HHT2. The presented HMEC-1 cell-based system therefore has the potential to be deployed as an in vitro model for HHT2 studies.
