O. Nunez Lopez1, X. Wang1, F. J. Bohanon1, H. Tie1, G. Graham1, R. S. Radhakrishnan1 1University Of Texas Medical Branch,Surgery,Galveston, TX, USA
Introduction:
Activated hepatic stellate cells (HSCs) are the main extracellular matrix (ECM) producers in liver fibrosis and play an important role in hepatic inflammation. Their inactivation and induction of apoptosis have become an important therapeutic strategy. HSP70 inhibitors have been reported to exert anti-proliferative effects in cancerous cells. However, little is known about the effects of HSP70 inhibition on hepatic fibrosis. Previously, our group reported that Oridonin, a plant-derived compound, has anti-inflammatory properties in HSCs via the NF-kB signaling pathway. In the present study, we determined the role of HSP70 inhibition alone and in combination with oridonin on the LPS-induced hepatic fibrogenic response in HSCs.
Methods:
The human activated HSC line LX-2 was used for this study. Cytokines production was measured by ELISA. Cellular proteins were analyzed by Western immunoblotting and immunofluorescence staining.
Results:
PES-CI (HSP70 inhibitor) treatment decreased the production of the LPS-induced pro-inflammatory cytokines IL-6 and MCP-1 in a dose-dependent manner in LX-2 cells. Moreover, micromolar concentrations of PES-CI (2.5µM) and Oridonin (2.5 µM) synergistically suppressed LPS-induced IL-6 and MCP-1 secretion. Compared to treatment with either PES-CI or oridonin alone, combined treatment (PES-CI + oridonin) resulted in significantly lower LPS-induced IKKβ and IκBα phosphorylation and lower LPS-induced NF-kBp65 nuclear translocation and DNA binding.
Conclusion:
Oridonin acts synergistically with the HSP70 inhibitor PES-CI. Combined treatment has anti-inflammatory properties via the NF-kB signaling pathway.