Deoxycholic Acid-Mediated Sphingosine-1-Phosphate Receptor 2 Signaling Exacerbates DSS-Induced Colitis through Promoting Cathepsin B Release

Figure 2

DCA activates ERK signaling and promotes cathepsin B release. (a) Immunoblot analysis of phospho-ERK, total ERK, phospho-AKT, and total AKT of LPS-primed J774A.1 macrophages treated with or without DCA (100 μM) for different time courses. β-Actin was regarded as a loading control. The relative intensity of the bands was quantitated. (b) LPS-primed J774A.1 macrophages were treated with DCA (100 μM) in the presence or absence of JTE-013 or U0126. The cells were incubated with cathepsin B substrate which emits a red signal upon cleavage by cathepsin B, followed by Hoechst staining (blue). (c–d) LPS-primed J774A.1 macrophages were treated with DCA (100 μM) in the presence or absence of JTE-013 or U0126, and cytosolic protein was extracted for the immunoblot analysis of mature cathepsin B (c) as well as fluorometric assay of cathepsin B activity (d). , , and . Error bars indicate s.e.m. The data shown are from 3 independent experiments.

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