17-AAG-Induced Activation of the Autophagic Pathway in Leishmania Is Associated with Parasite Death

• Published in: Microorganisms (Basel) 2021-05, Vol.9 (5), p.1089
• Main Authors: Petersen, Antonio Luis de O A, Cull, Benjamin, Dias, Beatriz R S, Palma, Luana C, Luz, Yasmin da S, de Menezes, Juliana P B, Mottram, Jeremy C, Veras, Patrícia S T
• Format: Article
• Language: English
• Subjects: Autophagy; Cell death; chemotherapy; Cutaneous leishmaniasis; Glycosomes; Heat shock proteins; Hsp90; Hsp90 inhibitors; Hsp90 protein; Leishmania; leishmaniasis; Lysosomes; Microscopy; Mortality; Parasites; Parasitic diseases; Phagocytosis; Phagosomes; Plasmids; Proteasomes; Proteins; Therapeutic targets; Tropical diseases; ubiquitin; Vector-borne diseases
• ISSN: 2076-2607; 2076-2607
• DOI: 10.3390/microorganisms9051089

The heat shock protein 90 (Hsp90) is thought to be an excellent drug target against parasitic diseases. The leishmanicidal effect of an Hsp90 inhibitor, 17-N-allylamino-17-demethoxygeldanamycin (17-AAG), was previously demonstrated in both in vitro and in vivo models of cutaneous leishmaniasis. Parasite death was shown to occur in association with severe ultrastructural alterations in , suggestive of autophagic activation. We hypothesized that 17-AAG treatment results in the abnormal activation of the autophagic pathway, leading to parasite death. To elucidate this process, experiments were performed using transgenic parasites with GFP-ATG8-labelled autophagosomes. Mutant parasites treated with 17-AAG exhibited autophagosomes that did not entrap cargo, such as glycosomes, or fuse with lysosomes. ATG5-knockout (Δ ) parasites, which are incapable of forming autophagosomes, demonstrated lower sensitivity to 17-AAG-induced cell death when compared to wild-type (WT) , further supporting the role of autophagy in 17-AAG-induced cell death. In addition, Hsp90 inhibition resulted in greater accumulation of ubiquitylated proteins in both WT- and Δ -treated parasites compared to controls, in the absence of proteasome overload. In conjunction with previously described ultrastructural alterations, herein we present evidence that treatment with 17-AAG causes abnormal activation of the autophagic pathway, resulting in the formation of immature autophagosomes and, consequently, incidental parasite death.