Dexamethasone enhances glucose uptake by SGLT1 and GLUT1 and boosts ATP generation through the PPP-TCA cycle in bovine neutrophils.

BACKGROUND

Clinical dexamethasone (DEX) treatment or stress in bovines results in extensive physiological changes with prominent hyperglycemia and neutrophils dysfunction.

OBJECTIVES

To elucidate the effects of DEX treatment in vivo on cellular energy status and the underlying mechanism in circulating neutrophils.

METHODS

We selected eight-month-old male bovines and injected DEX for 3 consecutive days (1 time/d). The levels of glucose, total protein (TP), total cholesterol (TC), and the proinflammatory cytokines interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α in blood were examined, and we then detected glycogen and adenosine triphosphate (ATP) content, phosphofructosekinase-1 (PFK1) and glucose-6-phosphate dehydrogenase (G6PDH) activity, glucose transporter (GLUT)1, GLUT4, sodium/glucose cotransporter (SGLT)1 and citrate synthase (CS) protein expression and autophagy levels in circulating neutrophils.

RESULTS

DEX injection markedly increased blood glucose, TP and TC levels, the Ca2+/P5+ ratio and the neutrophil/lymphocyte ratio and significantly decreased blood IL-1β, IL-6 and TNF-α levels. Particularly in neutrophils, DEX injection inhibited p65-NFκB activation and elevated glycogen and ATP contents and SGLT1, GLUT1 and GR expression while inhibiting PFK1 activity, enhancing G6PDH activity and CS expression and lowering cell autophagy levels.

CONCLUSIONS

DEX induced neutrophils glucose uptake by enhancing SGLT1 and GLUT1 expression and the transformation of energy metabolism from glycolysis to pentose phosphate pathway (PPP)-tricarboxylic acid (TCA) cycle. This finding gives us a new perspective on deeper understanding of clinical anti-inflammatory effects of DEX on bovine.