|099P London, UK
Does the bone hormone osteocalcin suppress inflammation within human aortic endothelial cells
Introduction: The bone hormone osteocalcin (OCN) has been recently connected to a number of extra-osseous functions, particular its undercarboxylated (ucOCN) form. Research into the effects of both ucOCN and the carboxylated (cOCN) form in the vasculature has resulted in a number of revelations including increased Akt phosphorylation and nitric oxide production in Human Aortic Endothelial Cells (HAoECs) and improved endothelial function in ApoE-/- mice when treated with OCN (1, 2). We hypothesised that OCN may therefore have a protective role in the vasculature and in atherosclerosis and may suppress inflammation.
Methods: HAoECs were grown until confluent in 24-well cell culture plates at passages ≤6. Cells were treated with or without 10ng/ml of ucOCN or cOCN. A 24 hour inflammatory protocol was followed in which cells were treated with IFN-γ and TNF-α (10ng/ml) or vehicle (n=8 for all conditions). Following the protocol cell media and lysates were collected appropriately. The inflammatory protocol was characterized by assessing phosphorylation status of VCAM-1, JNK, p38, IL-6 and IL-8.
Results: Treatment of HAoECs with ucOCN and cOCN did not affect any measured markers of inflammation, including the anti-inflammatory marker IL-10 (Figure 1).
Conclusions: Osteocalcin does not affect inflammation in HAoECs thus any potential protective role of OCN in atherosclerosis remains elusive. OCN may produce a different response in other vascular cells such as human aortic smooth muscle cells.
1. Jung CH, et al. (2013). Metabolism 62(9): 1250-7.
2. Dou J, et al. (2014). Cardiovasc Diabetol 13: 74.
Figure 1. Mean % change of measured markers of inflammation relative to the control and standard error of the mean (SEM) following different treatment conditions. *p<0.05 **p<0.01 ***p<0.001 ****p<0.0001. Abbreviations: ucOCN, undercarboxylated osteocalcin; cOCN carboxylated osteocalcin; inflm, inflammation.