Fat body-specific reduction of CTPS alleviates HFD-induced obesity

High fat diet (HFD)-induced obesity is a multi-factorial disease including genetic, physiological, behavioral, and environmental components. Drosophila has emerged as a useful model of metabolic diseases. Cytidine 5'-triphosphate synthase (CTPS) is a key enzyme for the de novo synthesis of CTP, governing cellular level of CTP and phospholipid synthesis. We have demonstrated that CTPS show the capacity to assemble into large filaments termed cytoophidia, which are evolutionarily conserved in bacteria, archaea and eukaryotes. Here, we show that CTPS acts in fat body to regulate body weight and starvation resistant in Drosophila. HFD-induced obesity elevates CTPS transcription and elongates cytoophidia in larval adipocytes. Fat body-specific depletion of CTPS alleviated HFD-induced obesity including body weight gain, lipid storage and TAG level. Moreover, a dominant negative form of CTPS reduces lipid accumulation and down regulates lipogenic genes. Therefore, our data not only provide a functional link between CTPS and lipid homeostasis, but also highlight the potential application of manipulating CTPS in the treatment of HFD-induced obesity.