Cell death mechanisms in Drosophila: Responses to infectious challenges

Cell death, a highly conserved and regulated process, plays a key role in development of an organism, immune responses, and tissue homeostasis. Often viewed in a negative light, it tightly regulates the proper balance of cell numbers and this fine balance carries the weight of life. In Drosophila melanogaster, a well-established genetic model, several forms of cell death including autophagy, apoptosis, and necrosis-like pathways are observed in response to the diverse bodily signals and infections. These distinct cell deaths are triggered through specific signaling pathways such as the Jun N-terminal kinase (JNK) pathway, the Toll and Imd immune pathways, and mitochondrial reactive oxygen species (ROS) mediated responses. This chapter explores the molecular regulation of these cell death pathways, emphasizing tissue-specific responses in Drosophila during bacterial and fungal infections. By understanding how various tissues, including the brain, gut, fat body, and muscles, differentially regulate cell death, we gain valuable insights into evolutionarily conserved strategies for host defense. Understanding these mechanisms helps reveal key biological principles relevant to immunity, pathology, and therapeutic development.