Induction of autophagy by a different TLR7 ligand, Loxoribine. (A) The observation of autophagosomes in the cytoplasm of Loxoribine (LOX)-treated
NLG 919 at 1 mM (340 μg/ml) concentration, compared to 0.04 mM (10 μg/ml) of IMQ. Caco-2 cells were seeded at 2 × 105 cells in 6-well culture plates and allowed to attach to plates for 2 days, after which LOX (340 μg/ml, 1 mM) or IMQ (10 μg/ml, 0.04 mM) was added for 1 days. The cellular morphology was observed under phase-contrast microscopy. Shown are representative images of autophagosomes. (B) Increased number of autophagic vesicles in 1 mM (340 μg/ml) of LOX- and 0.04 mM (10 μg/ml) of IMQ-treated Caco-2 cells. Autophagic vesicles in cytoplasm were counted in 50
cells per treatment. The mean numbers of autophagosomes ± SE per cells were shown. (C) The inhibition of survival via TLR7 activation either LOX or IMQ. One day of administration of 1 mM (340 μg/ml) LOX slightly suppressed the survival fraction compared to 0.04 mM (10 μg/ml) IMQ, as determined via a colorimetric cytotoxicity assay. Cells were seeded on 96-well plates at 5 × 103 cells and colorimetric cytotoxicity assays were performed. The results are presented as the mean percentages of triplicate measurements ± SE, subtracted from the surviving controls, with three independent experiments.
