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. Author manuscript; available in PMC: 2022 Sep 23.
Published in final edited form as: Curr Atheroscler Rep. 2021 May 10;23(7):33. doi: 10.1007/s11883-021-00934-3

Figure 1. miRNAs and circRNAs regulation of lipoprotein metabolism.

Figure 1.

miRNAs have been described to regulate the expression of genes involved in HDL biogenesis and maturation, cholesterol efflux and RCT from peripheral tissues to the liver; as well as genes that regulate triglyceride synthesis for incorporation into VLDLs and genes involved in LDL clearance from the circulation. The major transporter that regulates HDL biogenesis and efflux from the liver, ABCA1, is regulated by miR-33 and several other miRNAs in liver and macrophages. Moreover, miR-33 regulates a broad spectrum of genes that participate in liver and macrophages function, regulating HDL and lipid metabolism, RCT, autophagy and inflammation. Other miRNAs participate in RCT through the regulation of SR-B1 the liver receptor responsible of HDL uptake from the circulation. Finally, VLDL/LDL formation and uptake can be regulated by different miRNAs that regulate MTP expression in the liver and LDLR expression both in liver and macrophages. LDLR can be also indirectly regulated by miRNAS targeting PCSK9, which induces LDLR degradation. Besides miRNAs, circRNAs are arising as potential regulators of lipid metabolism, usually through the regulation of miRNAs. However, not many circRNAs have been proved for a relevant role in lipoprotein metabolism being merely suggested or potentially identified (illustrated as dashed line) based on target prediction. HDL: high-density lipoprotein; RCT: reverse cholesterol transport; VLDL: very low-density lipoprotein; LDL: low-density lipoprotein; ABCA1: ATP-binding cassette A1; ABCG1: ATP-binding cassette subfamily G member 1; SR-B1: scavenger receptor class B type 1; MTP: microsomal triglyceride transfer protein; LDLR: low-density lipoprotein receptor; PCSK9: proprotein convertase subtilisin/kexin type 9; circRNAs: circular RNAs; CYP7A1: cholesterol 7α-hydroxylase; CircFASN: Fatty acid synthase; PDE3B: phosphodiesterase 3B; CPT1: carnitine palmitoyltransferase 1a; CROT: carnitine O-octanoyltransferase; HADHB: hydroxyacyl-CoA dehydrogenase trifunctional multienzyme complex subunit beta; PGC1: peroxisome proliferator-activated receptor gamma coactivator 1-alpha; AMPK: AMP-activated protein kinase; ATG5: autophagy related 5; ATG7: autophagy related 7; LAMP1/2: lysosomal membrane proteins 1 and/or 2. This figure was created using Servier Medical Art illustration resources.