Dataset Information

Interactome analysis of Adenylyl cyclase-associated protein 1

ABSTRACT: The direct inflammatory action of proprotein convertase subtilisin/kexin type 9 (PCSK9) is examined in vitro in monocytes and endothelial cells, as well as via an in vivo atherosclerosis animal model. PCSK9 exacerbates atherosclerosis in low-density lipoprotein receptor (LDLR)-/- mice, indicating an inflammatory effect mediated independently of the LDLR pathway. Here we show that Adenylyl cyclase-associated protein 1 (CAP1) is the main binding partner of PCSK9, serving a crucial role in the pro-inflammatory cascade of PCSK9 by enabling the induction of cytokines, the activation of Toll-like receptor 4 (TLR4), and the upregulation of scavenger receptors. We also present spleen tyrosine kinase (Syk) and protein kinase C delta (PKCδ) as pivotal mediators in the inflammatory cascade subsequent to PCSK9-CAP1 binding. In human peripheral blood mononuclear cells (PBMCs), serum PCSK9 levels are positively correlated with Syk, PKCδ, and p65 phosphorylation. Notably, the CAP1-fragment crystallizable region (CAP1-Fc) shows superior efficacy in mitigating PCSK9-mediated inflammatory signal transduction when compared with the PCSK9 inhibitor, evolocumab.

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ORGANISM(S): Homo Sapiens (human)

SUBMITTER: Dohyun Han

LAB HEAD: Dohyun Han

PROVIDER: PXD047058 | Pride | 2024-06-16

REPOSITORIES: Pride

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Publications

PCSK9 stimulates Syk, PKCδ, and NF-κB, leading to atherosclerosis progression independently of LDL receptor.

Shin Dasom D Kim Soungchan S Lee Hwan H Lee Hyun-Chae HC Lee Jaewon J Park Hyun-Woo HW Fukai Mina M Choi EunByule E Choi Subin S Koo Bon-Jun BJ Yu Ji-Hoon JH No Gyurae G Cho Sungyoon S Kim Chan Woo CW Han Dohyun D Jang Hyun-Duk HD Kim Hyo-Soo HS

Nature communications 20240330 1

Proprotein convertase subtilisin/kexin type-9 (PCSK9) binds to and degrades low-density lipoprotein (LDL) receptor, leading to increase of LDL cholesterol in blood. Its blockers have emerged as promising therapeutics for cardiovascular diseases. Here we show that PCSK9 itself directly induces inflammation and aggravates atherosclerosis independently of the LDL receptor. PCSK9 exacerbates atherosclerosis in LDL receptor knockout mice. Adenylyl cyclase-associated protein 1 (CAP1) is the main bindi ...[more]

PMID: 38555386

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Project description:Background: The low-density lipoprotein receptor (LDLR) in the liver plays a crucial role in clearing low-density lipoprotein cholesterol (LDL-C) from the bloodstream. This process takes place mainly in the liver. Under atherogenic conditions, Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9), secreted by the liver, binds to LDLR on hepatocytes, preventing its recycling and enhancing its lysosomal degradation. This process reduces LDL-C clearance, promoting hypercholesterolemia. Epsins, a family of ubiquitin-binding endocytic adaptors, are key regulators of atherogenesis in lesional cells, including endothelial cells and macrophages. Given epsins' canonical role in regulating endocytosis of cell surface receptors, we aimed to determine whether and how liver epsins contribute to PCSK9-mediated LDLR endocytosis and degradation, thereby impairing LDL-C clearance and accelerating atherosclerosis. Methods: Liver-specific epsin knockout (Liver-DKO) atherosclerotic models were generated in ApoE-/- and PCSK9-AAV8-induced atheroprone mice fed on a Western diet. We utilized single-cell RNA sequencing, along with molecular, cellular, and biochemical analyses, to investigate the physiological role of liver epsins in PCSK9-mediated LDLR degradation. Additionally, we explored the therapeutic potential of nanoparticle-encapsulated siRNAs targeting epsins 1 and 2 in ApoE-/- mice with established atherosclerosis. Results: Western diet (WD)-induced atherosclerosis was significantly attenuated in ApoE-/-/Liver-DKO mice compared with ApoE-/- controls, as well as in PCSK9-AAV8-induced Liver-DKO mice compared with PCSK9-AAV8-induced wild-type (WT) mice accompanied by reductions in blood cholesterol and triglyceride levels. Mechanistically, single-cell RNA sequencing of hepatocytes and aortas isolated from atherosclerotic ApoE-/- and ApoE-/-/Liver-DKO mice revealed epsin-deficient Ldlrhi hepatocytes with diminished lipogenic potential. Notably, pathway analysis of hepatocytes showed increased LDL particle clearance and enhanced LDLR-cholesterol interactions under WD treatment in ApoE-/-/Liver-DKO mice compared with ApoE-/- controls, correlating with decreased plasma LDL-C levels. Furthermore, pathway analysis of the aortas showed attenuated inflammation and endothelial activation, coupled with reduced lipid uptake, and enhanced cholesterol efflux under WD treatment in ApoE-/-/Liver-DKO mice compared with ApoE-/- controls. Moreover, the absence of liver epsins led to an upregulation of LDLR protein expression in hepatocytes. We further demonstrated that epsins bind LDLR via the ubiquitin-interacting motif (UIM), enabling PCSK9-mediated LDLR degradation. Depleting epsins abolished this degradation, thereby preventing atheroma progression. Lastly, targeting liver epsins with nanoparticle-encapsulated epsins siRNAs effectively ameliorates dyslipidemia and inhibits atherosclerosis progression. These results are consistent with findings showing an increased epsin1 and epsin2 expression in atherosclerotic cardiovascular disease patients. Conclusions: Liver epsins drive atherogenesis by promoting PCSK9-mediated LDLR degradation, thereby elevating circulating LDL-C levels and heightening lesional inflammation. As such, targeting epsins in the liver represents a promising therapeutic strategy to mitigate atherosclerosis by preserving LDLR and enhancing LDL-C clearance in the liver.

			Action	DRS
	201712017_HEP_CAP1_1.raw	Raw
	201712017_HEP_CAP1_2.raw	Raw
	201712017_HEP_mFC_1.raw	Raw
	201712017_HEP_mFC_2.raw	Raw
	201712017_THP_CAP1_1.raw	Raw