JAK/STAT inhibition protects glucocorticoid receptor knockout mice from lethal malaria-induced hypoglycemia and hyperinflammation

Abstract Disease tolerance is a key defense mechanism that limits damage to the host without directly reducing pathogen levels. In malaria, these mechanisms are essential for preventing severe disease and death but remain poorly understood. In this study, we show that glucocorticoid receptor (GR)-mediated processes play a vital role in disease tolerance during Plasmodium chabaudi AS infection. GR deletion in infected mice resulted in lethal hypoglycemia and a cytokine storm. Hypoglycemia was driven by severe metabolic dysfunction in the liver and spleen, characterized by increased glucose uptake, glycogen depletion, a dominant glycolytic profile and reduced gluconeogenic gene expression. Importantly, this hypoglycemic state was strongly associated with overactivation of the JAK/STAT pathway and excessive cytokine expression. Treatment with the JAK1/2 inhibitor ruxolitinib significantly improved survival by preventing lethal hypoglycemia and suppressing hyperinflammation. Our findings reveal a novel link between GR signaling, STAT3 activation, cytokine expression and glucose metabolism during severe malaria. This underscores the critical role of GR-mediated processes in disease tolerance and highlights ruxolitinib as a promising adjuvant therapy for managing life-threatening metabolic complications in malaria.