Increased host ATP efflux and its conversion to extracellular adenosine is crucial for establishing Leishmania infection

Abstract

Intracellular survival of Leishmania donovani demands rapid production of host ATP for its sustenance. However, a gradual decrease in intracellular ATP in spite of increased glycolysis suggests ATP efflux during infection. Accordingly, upon infection, we show here that ATP is exported and the major exporter was pannexin-1, leading to raised extracellular ATP levels. Extracellular ATP shows a gradual decrease after the initial increase, and analysis of cell surface ATP-degrading enzymes revealed induction of the ectonucleotidases CD39 and CD73. Ectonucleotidasemediated ATP degradation leads to increased extracellular adenosine (eADO), and inhibition of CD39 and CD73 in infected cells decreased adenosine concentration and parasite survival, documenting the importance of adenosine in infection. Inhibiting adenosine uptake by cells did not affect parasite survival, suggesting that eADO exerts its effect through receptor-mediated signalling. We also show that Leishmania induces the expression of adenosine receptors A 2A R and A 2B R, both of which are important for anti-inflammatory responses. Treating infected BALB/c mice with CD39 and CD73 inhibitors resulted in decreased parasite burden and increased host-favourable cytokine production. Collectively, these observations indicate that infection-induced ATP is exported, and after conversion into adenosine, propagates infection via receptor-mediated signalling.

The Ecto‐5 ′nucleotidase/CD73 Mediates Leishmania amazonensis Survival in Macrophages

“…The expression of CD73 in resident peritoneal macrophages has been described in the previous studies [40,41]; however, to the best of our knowledge, no previous study has evaluated the expression of this enzyme after an extended period of incubation such as the one used in the present study. During infection, macrophages secrete ATP via pannexin channels [42][43][44] or P2X7 receptors [45]. Accumulation of Resident macrophages were obtained from naïve mice by injecting 10 ml of ice-cold PBS into the peritoneal cavity and rested for 72 h at 37 °C.…”

Peptidylarginine Deiminase 2 in Host Immunity: Current Insights and Perspectives

“…A previous study demonstrated that ATP induces PAD2 activity via P2X7 receptors (25). While ATP is required for almost all biological reactions as the universal energy source (115), once host cells are damaged, stressed, or infected by pathogens, intracellular ATP can be released to become extracellular ATP which serves as a key "danger" signaling molecule (116)(117)(118). Additionally, certain pathogens can also produce and secrete extracellular ATP (119,120).…”

Immunometabolism of Leishmania granulomas

“…15,76 How AMPK is activated in Leishmania-infected macrophages remains unclear. Leishmania infection can lead to the efflux of ATP, 77 which would alter intracellular pools of AMP/adenosine diphosphate/ATP and potentially activate AMPK in the host cell. The released ATP is converted to adenosine by the surfaceexpressed ectonucleotidases, CD39/CD73 and adenosine deaminase (ADA2), leading to the activation of G-protein receptors, A 2A R and A 2B R, which have also been shown to promote M2 polarization.…”

“…The released ATP is converted to adenosine by the surfaceexpressed ectonucleotidases, CD39/CD73 and adenosine deaminase (ADA2), leading to the activation of G-protein receptors, A 2A R and A 2B R, which have also been shown to promote M2 polarization. 77 AMPK can also be activated by cytoplasmic galectins that detect lysosomal damage, 78 although whether Leishmania amastigotes activate this pathway is unknown. More broadly, it remains unclear whether visceralizing Leishmania species simultaneously activate both AMPK and mTORC1 signaling pathways to their advantage.…”

“…Leishmania infection can lead to the efflux of ATP, 77 which would alter intracellular pools of AMP/adenosine diphosphate/ATP and potentially activate AMPK in the host cell. The released ATP is converted to adenosine by the surface‐expressed ectonucleotidases, CD39/CD73 and adenosine deaminase (ADA2), leading to the activation of G‐protein receptors, A 2A R and A 2B R, which have also been shown to promote M2 polarization 77 . AMPK can also be activated by cytoplasmic galectins that detect lysosomal damage, 78 although whether Leishmania amastigotes activate this pathway is unknown.…”