12-Lipoxygenase as a key pharmacological target in the pathogenesis of diabetic nephropathy

The characteristic features of diabetic nephropathy include thickening of the glomerular basement membranes, expansion of mesangium, and appearance of albumin in the urine (microalbuminuria and macroalbuminuria). Experimental studies have documented that 12-lipoxygenase (12-LOX) and its metabolite 12(S)-hydroxyeicosatetraenoic acid (HETE) play an important role in the pathogenesis of diabetic nephropathy. 12(S)-HETE may work in association with angiotensin II and transforming growth factor- β (TGF-β) reciprocally to induce fibrotic changes in the diabetic kidneys. The fibrotic actions of angiotensin II on the kidneys are mediated indirectly through an increase in the synthesis of 12(S)-HETE. Conversely, 12(S)-HETE may also enhance the actions of angiotensin II by upregulating the expression of AT₁ receptors on the glomerulus, mesangium, and podocytes. 12(S)-HETE may also cross-talk with TGF-β in a reciprocal manner to induce the fibrotic changes in the diabetic kidney. 12(S)-HETE-triggered signaling pathways may involve activation of p38 mitogen-activated protein (p38MAP) kinase, increase in cAMP-responsive element-binding protein (CREB) transcriptional activity, epigenetic changes involving histone methylation through an increase in histone methyltransferase activity along with an upregulation of cyclin-kinase inhibitors including, p16, p21, and p27. The present review discusses the role of 12-LOX in the pathogenesis of diabetic nephropathy along with the possible mechanisms.