Plasmodium Perforin-Like Protein Pores on the Host Cell Membrane Contribute in Its Multistage Growth and Erythrocyte Senescence

Swati Garg,Agam P Singh,Soumya Pati,Chandramohan Bathula,Rajagopal Ayana,Subhabrata Sen,Rahul S Hada,Inderjeet Kalia,Abhishek Shivappagowdar,Shailja Singh

doi:10.3389/fcimb.2020.00121

Abstract

The pore forming Plasmodium Perforin Like Proteins (PPLP), expressed in all stages of the parasite life cycle are critical for completion of the parasite life cycle. The high sequence similarity in the central Membrane Attack Complex/ Perforin (MACPF) domain among PLPs and their distinct functional overlaps define them as lucrative target for developing multi-stage antimalarial therapeutics. Herein, we evaluated the mechanism of Pan-active MACPF Domain (PMD), a centrally located and highly conserved region of PPLPs, and deciphered the inhibitory potential of specifically designed PMD inhibitors. The E. coli expressed rPMD interacts with erythrocyte membrane and form pores of ~10.5 nm height and ~24.3 nm diameter leading to hemoglobin release and dextran uptake. The treatment with PMD induced erythrocytes senescence which can be hypothesized to account for the physiological effect of disseminated PLPs in loss of circulating erythrocytes inducing malaria anemia. The anti-PMD inhibitors effectively blocked intraerythrocytic growth by suppressing invasion and egress processes and protected erythrocytes against rPMD induced senescence. Moreover, these inhibitors also blocked the hepatic stage and transmission stage parasite development suggesting multi-stage, transmission-blocking potential of these inhibitors. Concievably, our study has introduced a novel set of anti-PMD inhibitors with pan-inhibitory activity against all the PPLPs members which can be developed into potent cross-stage antimalarial therapeutics along with erythrocyte senescence protective potential to occlude PPLPs mediated anemia in severe malaria.

Highlights

Malaria remains a serious global health challenge and major roadblock for the economic growth of the poor and developing economies
To investigate whether the conservation of sequence is reflected in structural conservation, we in silico modeled the structure of Pan-active MACPF Domain (PMD) based on the Membrane Attack Complex/ Perforin (MACPF) domain of a closely related apicomplexan parasite T. gondii, TgPLP1
Despite abundant evidence that Plasmodium Perforin Like Proteins (PPLP) are crucial for the life cycle progression of malaria parasites, the development of chemotherapeutic interventions against them has not been explored

Summary

Introduction

Malaria remains a serious global health challenge and major roadblock for the economic growth of the poor and developing economies. The rapid emergence of drug-resistant malaria parasites has exceeded the rate at which anti-malarial therapies are presently being introduced. Though currently available antimalarial therapies target blood-stage to reduce the disease burden, the PfPLPs Form Pores on Erythrocytes next-generation therapeutics demands development of drugs with potent cross-stage protection, for complete prevention (WHO, 2018). In lieu of the same, molecular players performing multiple roles across the life cycle of the malaria parasite would serve as ideal targets for developing pan-active therapeutic interventions. In this regard, Plasmodium Perforin like proteins (PPLPs) are excellent candidates in this regard and need to be further characterized

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