Project description:We use the Plasmodium berghei rodent model to characterize the proteome of the final phase of liver stage development, the merosomes, packets of hepatic merozoites that bud from the host hepatocyte to initiate the blood stage of malaria. Plasmodium berghei WT ANKA strain was used to infect HepG2 hepatoma cells. Samples were fractionated by strong cation exchange, and nano-LC Orbitrap mass spectrometry was used to perform untargeted proteomic profiling of 3 biological replicates. Data was processed using MaxQuant and LFQ. Additional searches were performed to identify peptides from cleaved acetylated PEXELs (protein export elements) to identify proteins putatively exported to the host hepatocyte during liver stage development.
Project description:The liver stage of the etiological agent of malaria, Plasmodium, is obligatory for successful infection of its various mammalian hosts. Differentiation of the rod-shaped sporozoites of Plasmodium into spherical exoerythrocytic forms (EEFs) via bulbous expansion is essential for parasite development in the liver. However, little is known about the host factors regulating the morphological transformation of Plasmodium sporozoites in this organ. Here, we show that sporozoite differentiation into EEFs in the liver involves protein kinase Cζ-mediated NF-κB activation, which robustly induces the expression of C-X-C chemokine receptor type 4 (CXCR4) in hepatocytes and subsequently elevates intracellular Ca2+ levels, thereby triggering sporozoite transformation into EEFs. Blocking CXCR4 expression by genetic or pharmacological intervention profoundly inhibited the liver stage development of the P. berghei rodent malaria parasite and the human P. falciparum parasite also. Collectively, our experiments show that CXCR4 is a key host factor for Plasmodium development in the liver, and CXCR4 warrants further investigation for malaria prophylaxis.
Project description:Plasmodium falciparum (Pf) parasite development in liver represents the initial step of the life-cycle in the human host after a Pf-infected mosquito bite. While an attractive stage for life-cycle interruption, understanding of parasite-hepatocyte interaction is inadequate due to limitations of existing in vitro models. We explore the suitability of hepatocyte organoids (HepOrgs) for Pf-development and show that these cells permitted parasite invasion, differentiation and maturation of different Pf strains. Single-cell messenger RNA sequencing (scRNAseq) of Pf-infected HepOrg cells has identified more than 80 Pf-transcripts upregulated on day 5 post-infection. Transcriptional profile changes are found involving distinct metabolic pathways in hepatocytes with Scavenger Receptor B1 (SR-B1) transcripts highly upregulated. A novel functional involvement in schizont maturation is confirmed in fresh primary hepatocytes. Thus, HepOrgs provide a strong foundation for a versatile in vitro model for Pf liver-stages accommodating basic biological studies and accelerated clinical development of novel tools for malaria control.
Project description:Liver stage of malaria parasite exports SLTRiP and PB268 to the cytosol of parasite infected host cell. To know the host genes perturbed by WT-PBANKA, SLTRiP-KO and PB268-KO parasite growth, we did transcriptomic sequencing of infected host cells. We did mRNA sequencing of four samples for comparative analysis of WT and PB-knockout parasites infected host cells at 22 hours of post sporozoites infection.
Project description:Though the liver plays central roles in metabolism, the pivotal biological events throughout its aging are still unknown, resulting in ambiguity as to whether liver senescence could be reversed. To establish a criterion for liver-aging evaluation, dynamic hepatic biological features, including liver function, histology, transcriptional profile and protein expression, were screened in a cohort of Lewis rats at sequential chronological ages from 3 months to 24 months.
Project description:A major obstacle in deciphering the hepatic stage of the malaria parasite has been the challenges associated with culturing the infected hepatocytes through the entire liver stage cycle, including that of the dormant form known as hypnozoites. Primary hepatocytes lose their specialized functions in long-term in vitro culture. Hepatocyte infection represents the first step for clinically silent infection and development of malaria parasite Plasmodium in the liver. Thus this liver stage is an ideal target for development of novel antimalarial drugs and vaccine. However, drug discovery against Plasmodium liver stage is severely hampered by the poor understanding of host-cell and parasites interactions during the liver stage infection and development. In this study, we have performed tandem mass tags (TMT) labelling based quantitative proteomic analysis in simian primary hepatocytes cultured in three different systems of susceptibility to plasmodium infection. Our results represent the first documentation of potentially essential molecular markers including asialoglycoprotein receptor (ASGPR), apolipoproteins, squalene synthase and scavenger receptor B1 (SR-BI) required for productive infection and full development in relapsing Plasmodium species. The identification of these candidate proteins for constructive infection and development of Plasmodium in malaria paves the way to explore them as therapeutic targets.
Project description:Malaria, caused by Plasmodium parasites is responsible for the illness of millions of individuals each year. Plasmodium sporozoites inoculated by mosquitoes migrate to the liver and infect hepatocytes prior to release of merozoites that initiate symptomatic blood-stage malaria. Parasites are thought to be restricted to hepatocytes throughout this obligate liver-stage of replication and differentiation. In contrast to this notion, we found that a subset of hepatic dendritic CD11c+ cells co-expressing F4/80, CD103, CD207 and CSF1R, acquired a substantial parasite burden during the liver-stage of malaria, but only after initial hepatocyte infection. These CD11c+ cells found in the infected liver and liver-draining lymph nodes exhibited transcriptionally and phenotypically enhanced antigen-presentation functions; and primed protective CD8 T cell responses against Plasmodium liver-stage restricted antigens. Our findings uncover a novel aspect of Plasmodium biology as well as the fundamental mechanism by which CD8 T cell responses are primed against liver-stage malaria.
Project description:Increasing evidence suggests the liver as to be an effector against blood-stage malaria. Vaccination induces changes in the liver and survival of otherwise lethal blood-stage malaria of Plasmodium chabaudi which is associated with changes in the liver. Here, the time-course of expression of erythroid genes is investigated during infections with P. chabaudi in the liver of vaccination-protected and unprotected non-vaccinated mice.
Project description:Malaria-causing Plasmodium vivax parasites can linger in the human liver for weeks to years, and then reactivate to cause recurrent blood-stage infection. While an important target for malaria eradication, little is known about the molecular features of the replicative and non-replicative states of intracellular P. vivax parasites, or their human host-cell dependencies and the host responses to them. Here, we leverage a bioengineered human microliver platform to culture patient-derived P. vivax parasites in primary human hepatocytes and conduct transcriptional profiling. By coupling enrichment strategies with bulk and single-cell analyses, we captured both parasite and host transcripts in individual hepatocytes throughout the infection course. We define host- and state-dependent transcriptional signatures and identify previously unappreciated populations of replicative and non-replicative parasites, sharing features with sexual transmissive forms. We find that infection suppresses transcription of key hepatocyte function genes, and that P. vivax elicits an innate immune response that can be manipulated to control infection. Our work provides an extendible framework and resource for understanding host-parasite interactions and reveals new insights into the biology of P. vivax dormancy and transmission.
Project description:Malaria-causing Plasmodium vivax parasites can linger in the human liver for weeks to years, and then reactivate to cause recurrent blood-stage infection. While an important target for malaria eradication, little is known about the molecular features of the replicative and non-replicative states of intracellular P. vivax parasites, or their human host-cell dependencies and the host responses to them. Here, we leverage a bioengineered human microliver platform to culture patient-derived P. vivax parasites in primary human hepatocytes and conduct transcriptional profiling. By coupling enrichment strategies with bulk and single-cell analyses, we captured both parasite and host transcripts in individual hepatocytes throughout the infection course. We define host- and state-dependent transcriptional signatures and identify previously unappreciated populations of replicative and non-replicative parasites, sharing features with sexual transmissive forms. We find that infection suppresses transcription of key hepatocyte function genes, and that P. vivax elicits an innate immune response that can be manipulated to control infection. Our work provides an extendible framework and resource for understanding host-parasite interactions and reveals new insights into the biology of P. vivax dormancy and transmission.