Fig. 1: MB2mP6 blocks Gα₁₃ interactions with β₂ integrins and inhibit adhesion-dependent macrophage cytokine expression.

a Representative immunoblots (from three independent experiments) of anti-β₂ antibody-co-immunoprecipitated integrin β₂ subunit and Gα₁₃ in macrophages differentiated from PMA-stimulated THP-1 cells. The macrophages were pretreated with MB2mP6 or control peptide HLPN (50 μM) for 20 min and then stimulated with LPS (100 ng mL⁻¹) for the indicated time prior to immunoprecipitation. Immunoprecipitates and total cell lysates were then immunoblotted with both anti-β₂-integrin and anti-Gα₁₃ antibodies. b–e Comparison between MB2mP6 HLPN and scrambled peptide control (Scra) in Il-1β (b), Il-6 (c), Il-12 p40 (d), and Tnfα (e) mRNA expression in THP-1-derived macrophages stimulated with 100 ng mL⁻¹ LPS. The mRNA expression was detected by qRT-PCR (all groups, n = 4, independent cultures). f–i Comparison between adherent and non-adherent THP-1-derived macrophages in the levels of cytokine IL-1β (f), IL-6 (g), IL-12 p40 (h), and TNFα (i) expression as detected by qRT-PCR (all groups, n = 3, independent cultures). j No effect of MB2mP6 pretreatment (20−100 μM) on adhesion of THP-1-derived macrophages onto hICAM-1 (10 μg mL⁻¹) precoated in 48-well plates (all groups, n = 4, independent cultures). All data are shown as mean ± SEM. Data in (b–j) were analyzed by two-way ANOVA with the post hoc Bonferroni’s multiple comparisons test (b–e) or Sidak’s multiple comparisons (f–i) or Tukey’s multiple comparisons tests (j).