Hepatocyte-Specific Knockout of YAP Protects Against Atherosclerosis via Inhibition of ANGPTL3 in Mice.

Lipid-lowering therapy is a cornerstone in the treatment of atherosclerotic cardiovascular diseases. Although some lipid-lowering drugs have demonstrated positive effects in patients with atherosclerotic cardiovascular diseases, their effects are limited in those with homozygous familial hypercholesterolemia. It is essential to seek new lipid-lowering targets. YAP (Yes-associated protein) may be involved in lipid metabolism in the liver; therefore, we investigated the function of hepatocyte YAP in hyperlipidemia and atherosclerosis. Hyperlipidemia models were generated in apoE knockout (apoE-/-) mice or mice injected with adeno-associated virus 8-D377Y-mPCSK9, which degrades and deletes LDLR (low-density lipoprotein receptor), by being fed a high-cholesterol diet for 12 weeks. We measured the expression level of hepatic YAP in these apoE-/- mice. Next, we created YAPΔHep (hepatocyte-specific deletion of Yes-associated protein) apoE-/- mice to further determine the role of YAP in hyperlipidemia and atherosclerosis. AML12 (alpha mouse liver 12) cells and mice injected with AAV8-D377-mPCSK9 (adeno-associated virus 8 carrying the D377Y mutant of mouse proprotein convertase subtilisin/kexin type 9) or YAPΔHepapoE-/- mice were used to elucidate its mechanism. Finally, apoE-/- or LDLR knockout (LDLR-/-) mice were used to observe the therapeutic efficacy of adeno-associated virus 8-Alb (albumin)-shYAP (short hairpin RNA targeting for YAP) for hyperlipidemia and atherosclerosis. High-cholesterol diet-fed apoE-/- mice showed increased levels of YAP in the liver. Further investigation indicated that YAPΔHepapoE-/- mice exhibited lighter hyperlipidemia and atherosclerosis than YAPflox/floxapoE-/- mice fed with a high-cholesterol diet. Conversely, hepatocyte-specific overexpression of YAP (5S) deteriorated hyperlipidemia and atherosclerosis in high-cholesterol diet-fed apoE-/- mice. Furthermore, the lipid-lowering effect of YAP deficiency in hepatocytes was independent of LDLR. Hepatocyte-specific overexpression of ANGPTL3 (angiopoietin-like 3) aggravated hyperlipidemia and atherosclerosis in YAPΔHepapoE-/- mice, indicating that ANGPTL3 is responsible for the function of YAP in hyperlipidemia. Mechanistically, YAP upregulated ANGPTL3 via TEAD (TEA domain family member) 4 in hepatocytes independent of LDLR. Notably, adeno-associated virus 8-Alb-shYAP lowered lipid levels in apoE-/- or LDLR-/- mice. Taken together, our findings revealed a novel role for the YAP-TEAD4-ANGPTL3 axis in lipid metabolism independent of LDLR. Inhibition of hepatocyte YAP may be an effective lipid-lowering strategy for homozygous familial hypercholesterolemia.