HIF1A and rheumatoid arthritis: Under hypoxic conditions, HIF-1α increases the expression of the glucose transporters GLUT1 and GLUT3 to enhance glucose uptake, and it regulates the expression of hexokinase II, glyceraldehyde 3-phosphate dehydrogenase, lactate dehydrogenase (LDH), and mitochondrial cytochrome oxidase to enhance glycolysis in the RA synovial tissue.