The TLR4 adaptor TRAM controls the phagocytosis of Gram-negative bacteria by interacting with the Rab11-family interacting protein 2
Fig 3
Silencing of TRAM, but not MyD88, inhibits phagocytosis of E. coli in human macrophages.
Human primary macrophages (Mϕ) were treated with NS RNA, TRAM siRNA or MyD88 siRNA and stimulated with E. coli or S. aureus bioparticles for 15 min or 15+15 min. Phagocytosis was monitored by 3-D confocal microscopy and presented as mean bacterial count per cell (A) E. coli phagocytosis in Mϕ stimulated for 15 min or 15+15 min. (B) S. aureus phagocytosis in Mϕ stimulated for 15 min or 15+15 min. (C) Phagosome maturation of E. coli- and S. aureus phagosomes in the Mϕ stimulated for 15+15 from Fig 3A and 3B. (D) Phagocytosis of live E. coli and S. aureus in TRAM siRNA treated THP-1 cells. (E) Phagocytosis of live E. coli or S. aureus in MyD88 siRNA treated THP-1 cells. n = number of cells monitored. One-way ANOVA Kruskal-Wallis test (A-C) or Holm-Sidak´s test (D-E) with adj. P values, ** (p < 0.0027), *** (p = 0.0006), **** (p < 0.0001). Red bars: mean ± SD. Data are representative of three independent experiments.