How do sex hormones regulate the function of arteries and valves?

Heart disease and strokes affect about one person in three and are in part caused by arteries and valves becoming stiffened with calcium deposits (1). However, how this occurs and why heart disease is more prevalent among men is not fully known. Recent studies by our research group (2,3) have shown that testosterone causes the muscle cells found normally in the walls of arteries to partially transform themselves into bone cells and lay down deposits of calcium salts similar to the substances found in the skeleton. The overall result is a thickening and stiffening of the artery wall and a higher risk for heart disease. This project will assess the influence of oestrogen and testosterone on artery and valve development and function. It will utilise in vitro culture models of vascular cells and develop new in vivo mouse models of arterial and valve calcification. Studies will involve the assessment of calcification in vitro and in vivo through the quantification of calcium and phosphate deposition using biochemical assays and fluorescent probes. This will include the development of novel in vivo imaging protocols using state-of-the-art PET/computed

tomography (CT) scanning, a technique currently used to assess calcification in patients. We will also use our models of vascular calcification to investigate the role of different pathways that may be regulated by sex hormones during the calcification process; for example Wnt signalling and autophagy. In addition, RNAseq with subsequent informatics analysis will be undertaken to identify novel underpinning mechanisms. Techniques used will include histology, qPCR, western blotting, immunofluorescent staining and siRNA knockdown. Training: The supervisory team of this project merges expertise in cardiovascular biology (VEM, PH), calcification biology (VEM) and chemistry (PH) and in vivo surgery and imaging (PH). Training will be primarily through practical application of research techniques, analytical methods and study skills in the supervisors' laboratories, as well as The Centre for Cardiovascular Science's core imaging facility, which is responsible for the PET/CT scanner. Skills that will be acquired include cell and molecular biology techniques, microscopy, cell culture and in vivo techniques. Students are also encouraged to attend monthly Research Workshops dedicated to student and post-doctoral presentations. Anticipated outputs: The student will be encouraged to present their work at International and European scientific conferences and will have the opportunity to undertake a scientific exchange visit with The University of Hawaii, USA. Past students of the supervisors' have typically published at least 3 scientific papers during their studentships, and have subsequently secured high profile post-doctoral research positions in the UK, Europe and USA.

References: 1. Zhu D, Mackenzie NC, Farquharson C, MacRae VE 2012 Mechanisms and clinical consequences of vascular calcification. Front Endocrinol. 3:95. 2. Zhu D, Hadoke PW, Wu J, Vesey AT, Lerman DA, Dweck MR, Newby DE, Smith LB, MacRae VE 2016 Ablation of the androgen receptor from vascular smooth muscle cells demonstrates a role for testosterone in vascular calcification. Sci Rep 6:24807. 3. www.thenakedscientists.com/articles/interviews/why-do-men-have-more-heart-attacks