Inflammatory Immune Cytokine TNF-α Modulates Ezrin Protein Activation via FAK/RhoA Signaling Pathway in PMVECs Hyperpermeability

Scutellaria barbata D.Don extract regulates Ezrin-mediated triple negative breast cancer progress via suppressing the RhoA /ROCK1 signaling

Background

Triple-negative breast cancer (TNBC) lacks effective therapeutic targets. Scutellaria barbata D.Don (SB) has been revealed to have anti-breast cancer (BC) effect, but the effect of SB extract in TNBC is still unclear. Herein, this research delves into the underlying mechanism.

Methods

SB was extracted by solvent extraction, and the main components were identified using an Agilent 6,520 HPLC-Chip/Q-TOF (Chip/Q-TOF) MS system. In vitro cell experiments were conducted. The effects of SB extract alone, SB extract plus EGF, GSK alone, GSK plus Ezrin overexpression, or SB extract plus Ezrin overexpression on cell viability, invasion, migration, and apoptosis were examined by cell function experiments. The apoptosis- and RhoA/ROCK1 pathway-related protein levels were analyzed by western blot assay.

Results

Mass spectrometry analysis exhibited that SB extract mainly contains long-chain fatty acids and ursolic acid. SB extract mitigated TNBC cell biological phenotypes, apoptosis- and RhoA/ROCK1 pathway-related marker expressions, which were reversed by EGF. The further results found that GSK obviously weakens TNBC cell biological behaviors, apoptosis- and RhoA/ROCK1 signaling-related protein levels, while oe-Ezrin treatment reverses the effect of GSK on TNBC cells. Moreover, SB extract regulated Ezrin-mediated function of TNBC cells by impeding the RhoA/ROCK1 pathway.

Conclusion

Our findings demonstrated that SB extract regulated Ezrin-mediated proliferation, migration, invasion, and apoptosis of TNBC cells via suppressing the RhoA /ROCK1 signaling. Our results offer the experimental foundation for further investigation of the anti-cancer role of SB in TNBC cells.

Highlights

SB extract inhibits the biological phenotypes of TNBC cells.SB extract inhibits the biological behaviors of TNBC cells through the RhoA/ROCK1 pathway.SB extract modulates Ezrin-mediated TNBC cell proliferation, migration, invasion, and apoptosis via restraining the RhoA/ROCK1 signaling.

The ROCK-ezrin signaling pathway mediates LPS-induced cytokine production in pulmonary alveolar epithelial cells

BACKGROUND

Ezrin/radixin/moesin (ERM) proteins are members of the protein 4.1 superfamily and function as linkers that connect the actin cytoskeleton to the plasma membrane of cells. ERM also play critical role in the Lipopolysaccharide (LPS)-induced inflammatory response. However, the signaling mechanisms involved in this process remain unclear. In this study, we aimed to investigate the potential role of the rho-associated coiled-coil containing protein kinase (ROCK) pathway in LPS-induced ezrin phosphorylation and cytokine production in pulmonary alveolar epithelial cells.

METHODS

Cultured A549 and HPAEpiC cells were treated with LPS. The expression and localization of ezrin in A549 and HPAEpiC cells were then analyzed by western blotting and immunoflurescence. Activation of RhoA/ROCK was assessed by western blotting and RhoA activity assays. The interaction of ezrin with Syk and myeloid differentiation factor 88 (MyD88)/IL-1R-associated kinase 1 (IRAK-1) was investigated by co-immunoprecipitation. The activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) was measured with electrophoretic mobility shift assays and by western blotting. ELISA and western blotting were performed to detect the levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and high mobility group box 1 protein (HMGB1) release into the culture supernatant, and cellular HMGB1 levels.

RESULTS

LPS induced ezrin phosphorylation in a concentration- and time-dependent manner. The blockade of RhoA/ROCK inhibited LPS-induced ezrin phosphorylation and its translocation from the cytoplasm to the cell membrane. Co-immunoprecipitation assays further revealed that ezrin associated with Syk constitutively, but only associated with MyD88/IRAK-1 upon LPS challenge. Moreover, LPS-induced p38 and nuclear NF-κB activation was found to be ezrin dependent. The suppression of ezrin by siRNA or the blockade of ROCK activation with Y-27632 reduced the production of TNF-α, IL-1β, and HMGB1 in response to LPS.

CONCLUSIONS

Our findings reveal a novel regulatory mechanism involving ezrin in the LPS-induced production of pro-inflammatory cytokines, and highlight the importance of the RhoA/ROCK-ezrin/Syk-MyD88/IRAK1 axis. Data presented in this manuscript provide novel insights into the signaling pathways activated in pulmonary alveolar epithelial cells by LPS. Video Abstract.