- Identifying Novel signaling pathways regulating phagosome biogenesis
- Delineating the molecular mechanisms of phagosome maturation arrest induced by airborne fungi
- Exploring the mechanisms of intracellular persistence of certain fungal pathogens
- Exploring the role of NETosis and other specialized innate effector mechanisms in antifungal host defense
- Dissect molecular mechanisms of sepsis induced immunosuppression
- Define common defects in signaling pathways regulating phagosome biogenesis in acquired human immunodeficiencies
- Explore mechanisms of nutritional immunity in antifungal host defense
- Develop immunomodulatory strategies harnessing phagosome biogenesis to improve the outcome of infectious and inflammatory diseases
Developing A Systems Medicine approach to identify novel pathways regulating phagosome biogenesis with physiological role in fungal disease pathogenesis
Patients developing IMIs typically possess an array of complex, epigenetically-mediated immune defects related to the receipt of immunosuppressive therapies and other medical interventions, co-morbidities, underlying disease, and co-infections, coupled with incompletely characterized genetic predisposition to the disease. At the cellular level, all these acquired immune defects in diverse molecular pathways lead to impaired phagocyte effector function and the development of IMI. Because phagosome is the central regulator of phagocyte effector function, there is an unmet need of dissecting the molecular pathways of fungal phagosome biogenesis in order to gain insight in critical aspects of disease pathogenesis. As a proof of this concept, we have recently identified common defects in Aspergillus phagosome biogenesis in monocytes of patients with primary (chronic granulomatous disease) and secondary immunodeficiencies (receipt of high doses of corticosteroids, sepsis), uniquely predisposing for development of invasive aspergillosis.
In view of the complexity and diversity of immunosuppressive conditions leading to development of IMI a Systems Medicine approach is required to dissect the master regulatory pathways regulating fungal phagosome biogenesis that determine phagocyte dysfunction and development of disease. High throughput genomic studies in patients with acquired immunodeficiencies will lead in the identification of novel molecular targets associated with phagosome biogenesis defects.
Establishment of a high throughput assay in Drosophila melanogaster larvae for functional validation of novel candidate genes regulating phagosome biogenesis. In order to explore and validate the role of identified novel genes/targets identified in the proteomics approach we will perform an in vivo forward genetic screen in Drosophila. Phagocytosis and phagosome biogenesis is an evolutionarily conserved mechanism for pathogen elimination that relies on circulating phagocytic blood cells. Extensive functional characterization of the role of novel candidate genes in phagosome biogenesis will be performed ex vivo with the use of Drosophila S2 phagocytic cell line and in vivo
Validation of master regulatory pathways in human and murine models of invasive fungal infection. Importantly, the complexity of mammalian immune system relies on cross-talk and functional specialization of different immune cell subsets. In particular, among professional phagocytic cells, including monocytes/macrophages, dendritic cells and neutrophils, there are major differences in immune responses and signaling pathways following interaction of a particular PRR (e.g., Dectin-1) with its ligand (e.g. β-glucan). Therefore, priority will be given on in vivo validation of the relevant gene-targets in murine models of IMI. Our lab has acquired significant experience over the past 10 years on physiologically relevant models of fungal infections and conditional inactivation of genes in myeloid cells with the use of Cre LoxP system. Methods for assessment of primary murine phagocyte effector function ex vivo, including different source of macrophages and neutrophils, and in vivo following Broncho alveolar lavage (BAL) have been widely utilized in our lab.