Conclusion
The unfolded protein response is an essential cellular mechanism that promotes the survival of a cell during conditions of cellular stress, including intracellular parasitic infections. Pathogens are known to induce ER stress and UPR via interacting with the ER functions, while some are recognized to subvert the UPR to promote their survival and replication. Leishmania amozonensis activated the IRE1-XBP1 branch of the UPR to promote their growth in an IFN-1β depended manner, while activation of the PERK/eIF2α/ATF4 signaling cascade protected infected macrophages from oxidative stress. A mild ER stress response induced in Leishmania infantum infections may act as a possible adaptive mechanism for the cell to build up resistance to subsequent ER stress. Leishmania donovani infection induces the UPR in PERK dependent manner and has shown to delay apoptosis of infected macrophages. Thus, it is important to characterize the nature of the ER stress response to target the UPR pathway as a potential treatment option.
This review is intended to provide a comprehensive view of the available knowledge on the ER stress response markers and the UPR pathways characterized in intracellular parasitic infection by Trypanasomatids and particularly during infection Leishmania spp.infections.