HK2 and rheumatoid arthritis: Elevated HIF-1α not only increases the transcription of genes related to the macrophage glycolysis pathway (GLUT1) but also regulates enzymes necessary for macrophage glycolysis, such as lactate dehydrogenase A (LDHA), hexokinase type II (HKII), and pyruvate kinase isozyme typeM2 (PKM2), which promote macrophage polarization towards the M1-type and thus exacerbate RA [31].