Defining the Inflammation and Immunity Transcriptome in Severe Malarial Anemia for Immunotherapeutic Discovery

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PROJECT SUMMARY Despite advances in global health, malaria infects 212M and kills 429,000 people annually. Lack of effective vaccines and emergence of drug-resistant strains makes new therapeutic approaches essential. Childhood mortality rates in children <36 months remain exceedingly high in holoendemic Plasmodium falciparum transmission regions such as Siaya, Kenya, due to severe malarial anemia [SMA, hemoglobin (Hb)<5.0 g/dL]. Over the last 14 years, at our state-of-the-art clinical research facilities in Siaya, we focused on how innate immunity and co-morbidities influence clinical outcomes in childhood malaria. Over a three-year follow-up period, we found that 93% of the children had malaria, and 22.7% developed SMA. To identify the most significant pathways that discriminate SMA from milder forms of disease, we spent the last several years using a combination of global genomic approaches to create a convergent model for identification of disease signatures. These studies demonstrated that immune response genes are the strongest predictors for SMA, thus, narrowing the search from the entire genome to pathways involved in the host-immune response. Based on these findings and recent preliminary data, we propose to use targeted RNAseq with a platform that contains of 500 immune response genes (innate and adaptive immunity) which have not been concomitantly explored in malaria. Since our findings demonstrate that the immune response to P. falciparum drives adverse clinical outcomes for several weeks, even after clearance of the parasite, malarial anemia is an ideal candidate for immunotherapy. Thus, the overall goal of the project is to identify critical gene pathways within the transcriptome that mediate disease severity and then target these specific genes with compounds that elicit expression profiles witnessed in children with milder forms of disease. To achieve this goal, we will complete the following specific aims: 1) Determine how changing temporal dynamics of gene pathways in the Malarial Immunity Transcriptome promote SMA during acute disease; 2) Determine how changes in gene pathways in the Malarial Immunity Transcriptome mediate malarial severity throughout the development of naturally- acquired immunity; and 3) Identify immunotherapeutic targets in the Malarial Immunity Transcriptome that can be used to reduce malaria disease severity and improve clinical outcomes in future trials. To successfully complete these aims, we will determine how host and parasitic expression profiles impact on acute disease over 14 days (cohort 1) and validate these findings in a longitudinal birth cohort (cohort 2) during the child's 1st episode of acute malaria. We will also determine the impact of changing host and parasite temporal expression profiles on the development of naturally-acquired immunity over 36 months (cohort 2). Ex vivo samples from the two cohorts will be used to test the effect of immunotherapeutic compounds on host expression profiles. Accomplishing these goals will have broad reaching translational implications for: (1) identifying at-risk groups, and (2) prioritizing compounds that can be used to improve clinical outcomes in future immunotherapy trials.