Metabolic Shift During Tgf- Beta-Induced Collagen Synthesis

Introduction :Idiopathic pulmonary fibrosis (IPF) is a life-threatening disease characterised by excessive collagen-rich matrix formation in the lung. The role of myofibroblast metabolism in driving fibroproliferative pathomechanisms is becoming increasingly recognised and the aim of this study was to examine whether myofibroblasts increase their glucose uptake and glycolytic metabolism to support collagen synthesis. Methods: Primary human fibroblasts were stimulated with TGF-β (1ng/ml) for up to 48 hours. [ 3 H]2DG uptake was measured in control and TGF-β-stimulated fibroblasts. Levels of mRNA and protein expression for glucose transporters and key genes involved in glycolysis were also compared. Lactate levels were also measured. The effects of glucose deprivation and glycolytic inhibition (2DG) on collagen were measured under macromolecular crowding conditions. Results: Glucose uptake was significantly higher with TGF-β stimulation compared to control fibroblasts. Over the course of 48 hours, mRNA and protein levels of GLUT1 were significantly increased in TGFβ-treated cells. LDHa, PFKFB3 and HIF1α mRNA levels were also significantly higher. There was also significantly more lactate produced. Glucose starvation and inhibition of glucose metabolism significantly reduced TGF-β-stimulated collagen production. Conclusion: We have demonstrated that increased glucose uptake and glucose metabolism is a characteristic as well as a requirement for TGF-β induced collagen synthesis.