Communication is fundamental to life. Even within a single cell, intricate interactions among macromolecules ensure survival. In multicellular organisms, cells cooperate to maintain tissue — and, ultimately, organismal — homeostasis. Beyond well-characterized short-range interactions, an underappreciated realm of long-distance signaling is mediated by organ-to-organ communication.

Our lab investigates these long-range connections, with a particular focus on the interplay of blood cells with other tissues. Prior work from our group (Shim et al., 2012; Shim et al., 2013; Cho et al., 2018; Shin et al., 2024) showed that environmental cues such as odors, nutrients, and oxygen are detected by chemosensory receptors in sensory neurons; these signals are transmitted to the brain and trigger cascades that influence physiological homeostasis, including selective differentiation of myeloid blood cells.

We are now exploring how blood cells dynamically interact with other tissues to coordinate and maintain whole-animal physiology and development at an optimal state.

Drosophila blood cells (also known as hemocytes), analogous to vertebrate myeloid cells, are central players in cellular innate immunity. Beyond these canonical roles, our laboratory has shown that hemocytes also contribute to organismal metabolism and physiology (Shin et al., 2020), functioning as active participants in inter-organ communication rather than as isolated immune effectors. Moreover, recent work from our group demonstrates that crystal cells play a critical role in maintaining oxygen homeostasis through interactions with the tracheal system (Shin et al., 2024), providing the first evidence that insect hemocytes can perform functions analogous to vertebrate red blood cells. These studies imply that hemocyte subtypes—plasmatocytes, crystal cells, and lamellocytes—not only clear pathogens and debris but also exchange signals with metabolic tissues to modulate developmental and physiological programs. Together, these findings reveal conserved principles of myeloid-cell biology across vertebrates and invertebrates and motivate further study of the molecular mechanisms by which hemocytes coordinate systemic physiology beyond their conventional immune functions.