Regulation of Lactate dehydrogenase by STAT in the Differentiating Hemocytes of Drosophila

Abstract

Understanding the mechanism that maintains the homeostasis between stem cell progenitors and the differentiating cells is of prime importance in stem cell biology. While much attention has been given to the signaling cascades involved, recent studies have shed light on the role of cellular metabolism in modulating this balance. The larval lymph gland of Drosophila has come up as a wonderful model system to address these issues as they have the precursors, the differentiating hemocytes, and the niche cells that maintain homeostasis in close proximity. Previous reports demonstrated that the differentiating hemocytes are characterized by sporadic and less reticular mitochondria, a hallmark feature for cells relying primarily on glycolysis for their energy. Furthermore, it has also been documented that the differentiating cells communicate with the precursors in a STAT-dependent manner. As a part of a larger project trying to connect different signaling pathways to metabolic processes in the differentiating hemocytes, this study aims to understand whether JAK/STAT signaling regulates the expression of lactate dehydrogenase (ldh) in these cells. Our bioinformatic analyses revealed that ldh of Drosophila melanogaster has at least one Stat92e binding site, which is highly conserved in several other species of Drosophila. Furthermore, knocking down Stat92e in the differentiating hemocytes affects the expression of ldh. Finally, we are intrigued to check the physical binding of Stat92e to the regulatory region of the ldh gene.