Studies on the Regulation of Host Copper ATPase in Macrophage-Leishmania Interaction

Chakrabarty, Adrija (2023) Studies on the Regulation of Host Copper ATPase in Macrophage-Leishmania Interaction. Masters thesis, Indian Institute of Science Education and Research Kolkata.

Text (MS dissertation of Adrija Chakrabarty (18MS136)) Thesis_18MS136.pdf - Submitted Version Restricted to Repository staff only Download (3MB)

Abstract

Copper is an essential micronutrient for virtually all organisms. However excess free copper in a cell is toxic. These toxic properties of copper are known to be used as host defense response by many host species against pathogen invasions. Previous studies have shown host copper transporter ATP7A localizes to the Leishmania amastigote containing phagolysosomal compartments upon infection and pumps copper into these compartments to exert copper toxicity. Pathogen combats this toxicity by upregulating the expression of their own copper exporter LmATP7. Since LmATP7 is modulated upon infection and plays a key role in pathogenesis of Leishmania, and there is differential trafficking of host ATP7A, we speculated that ATP7A might also have an important role in the pathogenesis of Leishmania. So, we set out to determine the regulation and modification of ATP7A and its regulators upon L. major infection in macrophages. We show that L. major infection causes degradation and deglycosylation of ATP7A. We found that the deglycosylation is possibly mediated by host N-glycanase which shows an increase in transcript and protein levels upon infection. Chaperones of ATP7A, COMMD1 and Clusterin, which target ATP7A for degradation also show an increase in transcript levels. Both COMMD1 and Clusterin interact with ATP7A upon infection. We see that infection causes degradation of Clusterin but not COMMD1, primarily via the lysosomal pathway. Interestingly, we see that COMMD1 traffics from the cytoplasm to Leishmania compartments and also colocalizes with ATP7A, while we observe no change in the localization of Clusterin upon infection. These data establish that ATP7A and its regulators are highly modulated by the host and Leishmania upon infection and play a key role in the pathogenesis of Leishmania in macrophages.

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