Phosphoproteome and transcription factor activity profiling identify actions of the anti-inflammatory agent UTL-5g in LPS stimulated RAW 264.7 cells including disrupting actin remodeling and STAT-3 activation

UTL-5g is a novel small-molecule TNF-alpha modulator. It reduces cisplatin-induced side effects by protecting kidney, liver, and platelets, thereby increasing tolerance for cisplatin. UTL-5g also reduces radiation-induced acute liver toxicity. The mechanism of action for UTL-5g is not clear at the present time. A phosphoproteomic analysis to a depth of 4943 phosphopeptides and a luminescence-based transcription factor activity assay were used to provide complementary analyses of signaling events that were disrupted by UTL-5g in RAW 264.7 cells. Transcriptional activity downstream of the interferon gamma, IL-6, type 1 Interferon, TGF-β, PKC/Ca²⁺ and the Glucocorticoid Receptor pathways were disrupted by UTL-5g. Phosphoproteomic analysis indicated that hyperphosphorylation of proteins involved in actin remodeling was suppressed by UTL-5g (gene set analysis, FDR < 1%) as was phosphorylation of STAT3, consistent with the IL-6 results in the transcription factor assay. Neither analysis indicated that LPS-induced activation of the NF-kB, cAMP/PKA and JNK signaling pathways were affected by UTL-5g. This global characterization of UTL-5g activity in a macrophage cell line discovered that it disrupts selected aspects of LPS signaling including STAT3 activation and actin remodeling providing new insight on how UTL-5g acts to reduce cisplatin-induced side effects.