bioRxiv Science⌕ Search

Biology subjects

Schieke, S. M.

Publications and source records attributed to Schieke, S. M..

2 recordsLinked to original sources

The pyruvate branch point controls lymphoid cancer cell dissemination

Cancer cell dissemination critically determines clinical prognosis, yet metabolic dependencies and corresponding therapeutic targets during spread of lymphoid malignancies remain poorly understood. Here we show that the pyruvate branch point operates as a metabolic checkpoint for lymphoid cancer cell migration and disease dissemination through mitochondrial ROS (mROS)/HIF-1a signaling. Isolation of highly migratory mROShi cells led us to identify selective metabolic requirements of malignant lymphocyte migration and disease dissemination. Highly migratory cells show a reprogrammed metabolic profile characterized by increased glucose uptake and reduced glucose-carbon entry into the TCA cycle. Reprogramming of the TCA cycle with downregulation of citrate synthase provide the mechanistic basis for decreased pyruvate oxidation leading to increased migration and disease dissemination through mROS/HIF-1a signaling. Our findings connect central carbon metabolism and migratory capacity of lymphoid cancer cells and identify the pyruvate branch point as a metabolic switch and potential therapeutic target in lymphoid cancer cell dissemination.

cancer biology↗

Activation-induced shift in nutrient preference and function-specific nutrient dependence in human neutrophils

Neutrophils - the first responders in innate immunity - perform a variety of effector functions associated with specific metabolic demand. To maintain fitness and support functions, neutrophils have been found to utilize extracellular glucose, intracellular glycogen, and other alternative substrates. However, the quantitative contribution of these nutrients under specific conditions and the relative dependence of various cell functions on specific nutrients remain unclear. Here, using ex vivo and in vivo isotopic tracing, we reveal that under resting condition, human peripheral blood neutrophils, in contrast to in vitro cultured human neutrophil-like cell lines, rely on glycogen as a major direct source of glycolysis and pentose phosphate pathway. Upon activation with a diversity of stimuli, neutrophils undergo a significant and often rapid nutrient preference shift, with glucose becoming the dominant metabolic source thanks to a multi-fold increase in glucose uptake mechanistically mediated by the phosphorylation and translocation of GLUT1. At the same time, cycling between gross glycogenesis and glycogenolysis is also substantially increased, while the net flux favors sustained or increased glycogen storage. The shift in nutrient utilization impacts neutrophil functions in a function-specific manner. The activation of oxidative burst specifically depends on the utilization of extracellular glucose rather than glycogen. In contrast, the release of neutrophil traps can be flexibly supported by either glucose or glycogen. Neutrophil migration and fungal control is promoted by the shift away from glycogen utilization. Together, these results quantitatively characterize fundamental features of neutrophil metabolism and elucidate how metabolic remodeling shapes neutrophil functions upon activation.

biochemistry↗