OPN ELISA Kit, Human

OPN was initially identified in osteoblasts as a mineralization-modulatory matrix protein. Now OPN has been studied as a multifunctional protein that is upregulated in a variety of acute and chronic inflammatory conditions, such as wound healing, fibrosis, autoimmune disease, and atherosclerosis. OPN is highly expressed at sites with atherosclerotic plaques, especially those associated with macrophages and foam cells. In the context of atherosclerosis, OPN is generally regarded as a proinflammatory and proatherogenic molecule. However, the role of OPN in vascular calcification (VC), which is closely related to chronic and active inflammation, is that of a negative regulator because it is an inhibitor of calcification and an active inducer of decalcification. In addition to being produced by cells of osteoblastic lineage, OPN has been shown to play important roles in chemotaxis, adhesion, and proliferation, all of which allow it to mediate inflammation and immunity to infectious diseases. For example, granulomatous responses are associated with high levels of OPN expression and OPN can function as a Th1 cell cytokine, enhancing IL-12 while inhibiting expression of the Th2 cell cytokine IL-10. Furthermore, OPN can alter the sensitivity of hematopoietic cells to other cytokine stimuli.⁴