What are the key molecular differences in the endolysosomal pathway between professional and non-professional phagocytic cells?

Although multiple cell types are equipped with the ability to perform phagocytosis in invertebrates, in vertebrates, this indispensable task is delegated to the professional phagocytes, including microglia and macrophages. Indeed, it has been shown that circulating monocytes, the progenitors of tissue-resident macrophages, have limited phagocytic capacity, thus indicating that the ability to phagocytose is acquired during development and through differentiation. We are fascinated by multiple open-ended questions in the field of phagocytosis: Are there molecular signals that are necessary and sufficient to endow phagocytic capacity to cells? Is the endolysosomal cascade conserved between phagocytic and non-phagocytic cell populations? Do non-professional phagocytes, such as epithelial cells, lose their phagocytic potential as development progresses? What are the “find-me”, “eat-me”, and “don’t-eat-me signals” in play during “phagoptosis” (cell death by phagocytosis), and how is this delicate process regulated?

Through a combination of in vivo cell and developmental biology approaches, such as lineage tracing using live imaging, and in vitro molecular biology techniques, including lysosomal profiling, we will contribute to the knowledge of phagocytic machinery, capacity, and plasticity.