11TH NATIONAL CONGRESS WITH INTERNATIONAL PARTICIPATION AND 37TH ANNUAL SCIENTIFIC SESSION OF ROMANIAN SOCIETY FOR CELL BIOLOGY, June 20th-23rd, Constanta
Geanina Voicu1, Cristina Ana Constantinescu1,2, Daniela Rebleanu1, Agneta Simionescu3, Maya Simionescu1, Ileana Manduteanu1, Manuela Calin1
1Institute of Cellular Biology and Pathology “Nicolae Simionescu”, Bucharest, Romania; 2UASVM, Faculty of Veterinary Medicine, Bucharest, Romania; 3Department of Bioengineering, Clemson University, United States of America
Introduction. The pathological processes in the aortic valve (AV) disease associated with diabetes evolve from the early phase characterized by valvular endothelium inflammation and thickening of the basal lamina to the progressive phase, when the inflammatory processes may induce an osteogenic differentiation of valvular interstitial cells (VIC) leading to AV calcification.
Purpose. To investigate the effect of high glucose concentration on the osteodifferentiation of VIC.
Methods. Cultured VIC were exposed to media containing normal (NG, 5.5 mM) or high (HG, 25 mM) glucose concentrations in the absence or the presence (HGO) of factors known to induce osteodifferentiation (10 nM dexamethasone, 10 mM β-glycerophosphate, 50 µg/ml L-ascorbic acid). After different time intervals (2, 7, 14, 21 days), we analyzed (Western blot) the expression of proteins involved in VIC activation and osteodifferentiation (i.e. Runt-related transcription factor 2 (RUNX2), α-smooth muscle actin (SMA), bone sialoprotein (BSP), osteopontin (OSP), bone morphogenic protein 4 (BMP4) and alkaline phosphatase (ALP).
Results. Compared to normal glucose, high glucose concentrations potentiated the effect of osteogenic factors and determined an increased expression of RUNX2, a transcription factor involved in osteoblastic differentiation. The expression of key proteins involved in the phenotypic switch of quiescent VIC to myofibroblast and osteoblast phenotypes such as α-SMA, BSP, OSP, BMP4 and ALP were increased in VIC exposed to HG and HGO-cultured media in a time-dependent manner.
Conclusion. High glucose concentrations potentiate the effect of osteogenic factors and increase the expression of proteins involved in VIC activation and osteodifferentiation.
Acknowledgements. This work was supported by the THERAVALDIS Project: MySMIS: 104362, contract number 115/13.09.2016.
Key words. aortic valve, calcification, valvular interstitial cells, high glucose.