Autophagy induced by 2-deoxy-D-glucose suppresses intracellular multiplication ofLegionella pneumophilain A/J mouse macrophages

Abstract

Legionella pneumophila Philadelphia-1 (Lp-1) can grow intracellularly in A/J mouse peritoneal macrophages (A/J Mphi). We previously reported that 2-deoxy-D-glucose (2dG), when added in macrophage culture medium, inhibited the intracellular multiplication of Lp-1 in A/J Mphi. We found that 1 mM of 2dG causes LC3-II-conversion that reflects an induction of autophagy and that 1 and 10 mM of 2dG induced apoptosis associated with caspase-4 activation. We therefore investigated whether 2dG-induced autophagy or apoptosis suppresses the replication ofLp-1 in 2dG-treated A/J Mphi. When the autophagy-related (Atg)gene Atg5 was knocked down by RNA interference, the Atg5-siRNA-transfected cells revealed an enhanced replication of Lp-1 in A/J Mphi compared with the non-targetting siRNA-transfected cells. However, caspase-4 inhibitor did not affect the 2dG-induced inhibition of intracellular multiplication of Lp-1 in A/J Mphi. These findings suggested that autophagy, not apoptosis, suppressed the intracellular growth of Lp-1 in A/J Mphi when 1 or 10 mM of 2dG were added to the culture media.

Caloric Restriction Mimetic 2-Deoxyglucose Antagonizes Doxorubicin-induced Cardiomyocyte Death by Multiple Mechanisms

“…Indeed, we confirmed the ability of 2-DG to induce autophagy in cardiomyocytes (Fig. 6), consistent with findings in other cell types (63,64). Autophagy is the primary cellular pathway for lysosomal degradation and recycling of long lived proteins and organelles, which plays an extremely important role in cytoplasmic quality control and maintaining cellular homeostasis under both normal and path- ological conditions.…”

“…2C), two pathways that negatively regulate autophagy. Thus, it is very likely that 2-DG could induce autophagy in cardiomyocytes as it did in other cell types (63,64). To test if 2-DG can indeed trigger autophagy in cardiomyocytes, we infected NRC with AdGFP-LC3 and then treated cells with 500 M 2-DG.…”

Legionella pneumophila

“…When expression of the autophagy component ATG5 is silenced, L. pneumophila replication in A/J macrophages increases. Additionally, replication of L. pneumophila decreases slightly when autophagy is induced exogenously, suggesting that autophagy contributes to restriction of L. pneumophila replication (Matsuda et al, 2009). Under low MOI infection conditions where there is minimal induction of pyroptosis, it was revealed that the induction of autophagy dampens pyroptosis in response to L. pneumophila, and turnover of autophagosomes requires NAIP5, NLRC4, and caspase-1 (Byrne et al, 2013).…”

Master Manipulators: An Update on Legionella Pneumophila Icm/Dot Translocated Substrates and their Host targets

“…Proteins required for initiation of autophagosome formation, ATG7, and autophagosome maturation, ATG8, localize to the LCV during infection of these cells, suggesting that autophagy may play an antimicrobial role on the host response to Legionella [79]. Evidence in support of this hypothesis is provided by siRNA knockdown experiments in which the depletion of the critical autophagy factor ATG5 results in an increase in intracellular replication of Legionella during infection [76,80]. The manner in which this pathway is triggered, however, remains a mystery.…”