TIMP1 and rheumatoid arthritis: Single-cell RNA sequencing of RA-FLS suggests an escalated glycolytic program, with many cells expressing higher levels of glycolytic pathway enzymes, including hexokinase 2 (HK2), glucose transporter 1 (GLUT1), tissue inhibitor of matrix metalloproteinase 1 (TIMP1), and hypoxia-inducible factor 1 alpha (HIF1α) (7).