Glucose restriction inhibits glycolytic flux and limits proliferation in lung microvascular endothelial cells

Abstract

Pulmonary microvascular endothelial cells (PMVECs) exhibit increased glycolytic flux, which may contribute to their highly proliferative nature. We therefore sought to determine whether PMVECs rely on extracellular glucose to sustain glycolysis and growth under normoxic conditions. We performed growth curves and pH measurements using PMVECs and pulmonary artery endothelial cells (PAECs) in different glucose concentrations: High (22 mM), normal (11 mM) and low (5 mM). PMVEC proliferation was greatest in high glucose, and decreased progressively with lower glucose concentrations. In contrast, glucose concentration did not affect PAEC growth. Whereas PMVECs acidified the media in high glucose, they did not acidify the media at low glucose concentrations; PAECs did not acidify the media at any glucose concentration. QRT‐PCR analysis for glucose transporter‐1 (GLUT‐1), hexokinase‐2 (HK‐2), phosphofructokinase (PFK), and lactate dehydrogenase (LDH) revealed that media glucose did not influence upon the expression of these key glycolytic enzymes, suggesting genes responsible for increased glycolysis are constitutively upregulated in PMVECs. The constitutive upregulation of GLUT‐1, HK‐2, PFK, and LDH in PMVECs illustrate the intrinsic preference of these cells to use aerobic glycolysis during proliferation. Thus, glucose availability is a key determinant of growth and acidosis in PMVECs. HL66299.