Investigation of the therapeutic potential of recombinant BMP10 in an adult mouse model of HHT1 and the crosstalk between BMP and VEGF signalling

Introduction: Type I Hereditary Haemorrhagic Telangiectasia (HHT) is caused by mutations in ENG, encoding endoglin protein which is a coreceptor for BMP9 and BMP10. Endothelial-specific, homozygous deletion of Eng in adult mice (Eng-iKOe) has been shown to model the HHT phenotype, with the development of arteriovenous malformations (AVMs) in the pubic symphysis, associated high-output heart failure, via dysregulated BMP and VEGF signalling pathways. We hypothesised that treatment with recombinant BMP10 protein would restore BMP signalling and rescue disease phenotype. Methods: Human prodomain-bound BMP10 (pBMP10) was generated in-house. The mouse colony was transferred from Newcastle to Cambridge for rederivation. Adult Tg(Cdh5- cre/ERT2)1Rha; Engfl/fl mice were injected with tamoxifen to induce Eng knockout in endothelial cells, followed by either pBMP10 or PBS intraperitoneal administration. Tamoxifen-treated Engfl/fl mice were used as pseudo-wild-type controls. AVM formation was evaluated using latex blue perfusion. Heart hypertrophy was evaluated by measuring heart weight over body weight, or heart weight over tibia length ratios, and histochemistry. Heart function was evaluated using echocardiography. Heart and lung tissues were analysed for protein and mRNA levels of various targets. The crosstalk between BMP and VEGF signalling was investigated using in vitro cell biological studies in human endothelial cells. Results: Eng-iKOe mice developed AVMs in the pubic symphysis from day 10, and their formation was prevented by daily pBMP10 treatment. The pBMP10 treatment reduced ventricular hypertrophy in Eng-iKOe mice. Enlarged cardiomyocytes and elevated Acta1 mRNA levels were partially rescued following pBMP10 treatment. Eng-iKOe mice showed reduced collagen coverage of the cardiac blood vessels, which was fully restored after pBMP10 treatment. The echocardiography studies showed partial restoration in ejection fraction and fractional shortening following pBMP10 treatment. There was no change in the collagen coverage of pulmonary vessels, but reduced Akt and Erk1,2 activation was observed in the Eng-iKOe lungs. Additionally, reduced Alk1 and Bmpr2 mRNA expression was fully rescued after pBMP10 treatment. In the in vitro analysis of human endothelial cells, BMP and VEGF ligands modulated common target genes such as FOS, ESM1, PlGF, and ET1, they will be further investigated in the mouse tissues. Conclusion: Treatment with pBMP10 can prevent arteriovenous malformations in adult female mice and it can partially rescue the heart dysfunction phenotype in adult male mice.

Name dc:type.qualificationname

Doctor of Philosophy (PhD)

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

University of Cambridge

Year dc:date.issued

2024

Author dc:creator

• Kostrzyńska, Karolina

Advisor dc:contributor.advisor

• Li, Wei

• BMP10
• HHT

Licence

• https://www.repository.cam.ac.uk/bitstreams/c441a829-db6f-454d-b355-0a51e30a6fad/download
• http://purl.org/NET/rdflicense/allrightsreserved

Language dc:language

eng

DOI dc:identifier.doi

https://doi.org/10.17863/CAM.117262

OAI identifier oai:identifier

oai:www.repository.cam.ac.uk:1810/382467