Craig Wheelock

Helminths are multicellular parasites with potent regulatory effects on immune responses in infection and inflammation. We have recently identified an immune regulatory protein of the helminth Heligmosomoides polygyrus bakeri (Hpb), glutamate dehydrogenase (GDH), which modulates macrophage activation and allergic airway inflammation when administered in a murine asthma model. Here, we aim to characterize the mechanisms of action and immune regulatory effects of Hpb GDH in models of infection and vaccination. In part A of the project, we intent to identify the cellular interaction partners of Hpb GDH by co-immunoprecipitation and pull-down experiments using Strep-tagged Hpb GDH followed by mass spectrometry-based proteomics. By determining the structure of Hpb GDH and its identified interaction partners using X-ray crystallography and cryo-EM, we aim to gain further insights into the structural particularities of Hpb GDH compared to its mammalian homologues and into the molecular interactions with its cellular targets. Based on our recent findings, suggesting histone 3 lysine 27 acetylation (H3K27ac) as a mechanism mediating the Hpb GDH-driven modulation of macrophage gene expression, we will perform ChIP sequencing to identify loci that are epigenetically targeted by Hpb GDH. These structural and mechanistic insights will be instrumental for further developing Hpb GDH as a new biotherapeutic against airway disease. In part B of the project, we aim to identify the relevance of Hpb GDH-driven cytokine production for the protein’s effects on host defense and vaccine responses. Our RNA sequencing data indicate that Hpb GDH induces a strong type I interferon (IFN) and IL-12 cytokine signature. We will study effects of Hpb GDH in mice lacking IFN signaling in the hematopoietic or myeloid compartment (Ifnar fl/fl x Vav1Cre/ Lyz2Cre/ Cx3cr1Cre) or with global deficiencies in IL-12 family members (Il12b-/-, Ebi3-/-) in established mouse models of helminth infection. Effects of Hpb GDH on vaccination efficacy against major human pathogens as well as roles of IL-12 family cytokines in the regulation of vaccine-induced T-cell responses will be elucidated in mouse models of BCG and influenza vaccination. In summary, our work will contribute to a better understanding of the regulation of host defense, inflammation and vaccine responses by helminth molecules. The proposed studies may foster the translation of Hpb GDH into a novel biotherapeutic for the treatment of infectious and inflammatory diseases.

Asthma ranks among the most common chronic diseases of industrialized countries. Upwards of 20% of asthmatics present with difficult to control conditions that often respond poorly to current therapies, creating a significant unmet need to optimize individual patient treatment. Asthma is a general term used for a broad spectrum of loosely defined clinical conditions for which there is no defined biochemical description. Metabolomics provides a real-time indicator of biological status, reflecting the integrated result of genetic and environmental interactions, as well as treatment responses, making it ideally suited for molecular characterization of asthma. This project will use metabolomics to identify molecular phenotypes of severe airway disease. We will perform the largest meta-analysis of metabolomics to date consisting of tens-of-thousands of individuals, which will be complemented with metabolomics and lipid mediator analysis of treatment interventional studies. These data will be integrated using novel bioinformatics approaches to identify key metabolites that discriminate phenotypes and treatable endotypes. This information will be used to develop a targeted assay for asthma molecular phenotyping. The assay will be tested in validation cohorts to determine accuracy in stratifying individuals for treatment. The development of a high-throughput targeted molecular phenotyping panel will enable clinical translation and actualize precision medicine treatment for asthma.