Fig. 5: Function of SLP76 in RAGE-mediated cytokine and chemokine expression.

a–f Inhibitory effect of AGER and SLP76 gene deficiency on the mRNA expression of proinflammatory cytokines and chemokines. BMDMs were isolated from WT, AGER^−/−, or SLP76^−/− mice and were then stimulated with or without AGEs for 3 h. The levels of mRNAs encoding cytokines and chemokines in BMDMs were quantitated by real-time PCR (n = 5). *P < 0.05, ***P < 0.001, ****P < 0.0001 compared with the WT group (two-way ANOVA with Tukey post hoc). g–l Effect of AGER and SLP76 gene deficiency on cytokine and chemokine production in BMDMs. BMDMs were isolated from WT, AGER^−/−, or SLP76^−/− mice and were then stimulated with or without AGEs (100 μg/ml) for 12 h. The cytokines and chemokines in culture media were quantitated by using a multiplex LiquiChip system (n = 3). *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001 compared with the WT group (two-way ANOVA with Tukey post hoc). m The blocking mechanism of the TAT-SAM peptide on RAGE-mediated cell signaling. After AGEs bind with the cell surface receptor RAGE, SLP76 is recruited to the cytosolic tail of RAGE as an adaptor protein to transduce signals from the extracellular environment into the cell. A peptide containing the SAM domain was delivered into cells via the TAT CPP, thus blocking the interaction between RAGE and endogenous SLP76 through competitive binding with the cytosolic tail of RAGE, which resulted in inhibition of the signaling process mediated by RAGE. n–s Effects of the synthetic TAT-SAM peptide on AGE-induced production of cytokines and chemokines. RAW264.7 cells were pretreated with the TAT-SAM peptide or with TAT alone for 1 h and were then subjected to stimulation with AGEs for 12 h. The levels of cytokines and chemokines in culture media were quantitated by using a multiplex LiquiChip system (n = 3). *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001 compared with the untreated group; ^#P < 0.05, ^##P < 0.01, ^###P < 0.001, ^####P < 0.0001 compared with the TAT group (one-way ANOVA with Tukey post hoc). Data are presented as mean ± SD in (a–i) and (n–s). Source data are provided as a Source data file.