Communication is fundamental to life. Even within a single cell, intricate interactions among macromolecules ensure its survival. In multicellular organisms, the cells collaborate to maintain tissue and, in turn, the entire organism's homeostasis. Besides the well-established short-range interactions, there are an underappreciated realm of long-distance connections, facilitated by organ-to-organ communications.

Our lab delves into the intriguing world of these organ-to-organ connections, with a particular focus on the intricate interplay between brain chemosensation, immunity, and hematopoiesis. Previous studies (Shim et al., 2012; Shim et al., 2013; Cho et al., 2018) conducted within our lab have unveiled how environmental factors, such as odors, nutrients, and oxygen levels, are sensed by chemical receptors within sensory neurons. These sensory signals travel to the brain, triggering a cascade of events that ultimately influence physiological homeostasis, including the selective differentiation of myeloid blood cells.

We are now exploring the possibility of hemocytes and the hematopoietic organ, the lymph gland, engaging in dynamic interactions with various tissues to collectively maintain animal physiology at an optimum state.

Due to their simplicity, Drosophila chemoreceptors and their downstream circuits serve as an excellent model for exploring evolutionarily conserved characteristics of sensory neurons. While chemosensation typically elicits behavioral responses in animals, recent transcriptome analyses have unveiled the existence of chemosensory receptors in non-neuronal tissues. This observation, although not entirely surprising, provides a novel perspective for advancing our understanding of chemosensory receptor biology. For example, in vertebrates, the carotid body chemoreceptor, which monitors arterial blood oxygen levels, exemplifies a non-neuronal chemoreceptor. It associates its activity with carbon dioxide-sensing neurons in the brainstem called retrotrapezoid neurons (RTN). This discovery broadens the horizons of chemosensory receptor research

Drosophila blood cells, akin to myeloid blood cells in vertebrates, have a fundamental role in cellular immunity. Beyond their traditional functions, studies in our lab have unearthed their involvement in metabolism and physiology (Shin et al., 2020). These discoveries enhance our comprehension of the shared significance of myeloid blood cells across both vertebrates and invertebrates.