Low-density lipoprotein cholesterol metabolism pathway

The **low-density lipoprotein cholesterol metabolism pathway** refers to the series of biochemical processes responsible for the synthesis, transport, cellular uptake, storage, and elimination of low-density lipoprotein-associated cholesterol in the body. This system involves multiple classes of lipoproteins—chylomicrons carry dietary fats from the intestine; very-low-density lipoproteins are synthesized by the liver and deliver triglycerides/cholesterol; intermediate-density lipoproteins are VLDL remnants processed further into low-density lipoproteins. **Low-density lipoproteins** are rich in cholesteryl esters and serve as the primary vehicle for delivering endogenous cholesterol from the liver to peripheral tissues via circulation. Uptake into cells occurs through receptor-mediated endocytosis involving cell surface LDL receptors. Regulation occurs at several levels—transcriptional control via SREBP2 increases both HMG-CoA reductase activity for de novo synthesis and upregulates LDL receptor expression when intracellular stores are low. Excess cellular or systemic LDL leads to down-regulation or degradation pathways mediated by proteins like PCSK9. Disruption or dysregulation results in elevated circulating LDL ("bad" cholesterol), which promotes foam cell formation within arterial walls—a key event in **atherosclerosis** development[1][2][3][4]. Therapeutic interventions focus on reducing circulating LDL-C through inhibition of its synthesis/absorption or increasing its clearance via upregulated receptor activity. Note on correctness: The "low-density lipoprotein cholesterol metabolism pathway" is **not itself a molecular target**, but rather describes an interconnected set of processes involving many molecules/proteins/enzymes/receptors such as HMG-CoA reductase (**HMGCR**), low-density lipoprotein receptor (**LDLR**), apolipoprotein B100 (**apoB100**), proprotein convertase subtilisin/kexin type 9 (**PCSK9**) among others[3]. For structured data purposes focused on drug targets/receptors/enzymes/etc., it would be more appropriate to specify one such component—for example "Low-density lipoprotein receptor"—rather than referring broadly to an entire metabolic network/pathway. If you need information about specific molecular targets within this pathway—such as "Low-density lipoprotein receptor," "HMG-CoA reductase," etc.—please specify which one so that detailed structured information can be provided accordingly.

Other names

LDL cholesterol metabolismLDL-C pathwayCholesterol transport and metabolism (LDL-related)Cholesterol homeostasis (LDL-mediated)

Drugs targeting this pathway act by various mechanisms including: - Inhibition of HMG-CoA reductase to reduce endogenous cholesterol synthesis (statins) - Inhibition of intestinal cholesterol absorption (ezetimibe) - Upregulation of LDL receptor expression to increase hepatic clearance of LDL from plasma (statins, PCSK9 inhibitors) - Binding bile acids in the intestine to promote excretion and upregulate hepatic conversion of cholesterol into bile acids (bile acid sequestrants)