Neuraminidases 1 and 3 Trigger Atherosclerosis by Desialylating Low‐Density Lipoproteins and Increasing Their Uptake by Macrophages

Demina, E. P.; Smutova, Victoria; Pan, Xuefang; Fougerat, Anne; Guo, Tianlin; Zou, Chunxia; Chakraberty, Radhika; Snarr, Brendan D.; Shiao, Tze Chieh; Roy, René; Orekhov, Alexander N.; Miyagi, Taeko; Laffargue, Muriel; Sheppard, Donald C.; Cairo, Christopher W.; Pshezhetsky, Alexey V.

doi:10.1161/jaha.120.018756

Cited by 45 publications

(39 citation statements)

References 80 publications

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“…This suggested that the atheroprotective effects of ASGR1 LOF extended beyond reduction of serum LDLc and could implicate extrahepatic functions of ASGR1, e.g. , in macrophages ( 36 ).…”

Section: Discussionmentioning

confidence: 99%

Asialoglycoprotein receptor 1 is a novel PCSK9-independent ligand of liver LDLR cleaved by furin

Susan‐Resiga

Girard

Essalmani

et al. 2021

Journal of Biological Chemistry

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The hepatic carbohydrate-recognizing asialoglycoprotein receptor (ASGR1) mediates the endocytosis/lysosomal degradation of desialylated glycoproteins following binding to terminal galactose/N-acetylgalactosamine. Human heterozygote carriers of ASGR1 deletions exhibit ∼34% lower risk of coronary artery disease and ∼10% to 14% reduction of non-HDL cholesterol. Since the proprotein convertase PCSK9 is a major degrader of the low-density lipoprotein receptor (LDLR), we investigated the degradation and functionality of LDLR and/or PCSK9 by endogenous/overexpressed ASGR1 using Western blot and immunofluorescence in HepG2-naïve and HepG2-PCSK9-knockout cells. ASGR1, like PCSK9, targets LDLR, and both independently interact with/enhance the degradation of the receptor. This lack of cooperativity between PCSK9 and ASGR1 was confirmed in livers of wildtype (WT) and Pcsk9 −/− mice. ASGR1 knockdown in HepG2-naïve cells significantly increased total (∼1.2-fold) and cell-surface (∼4-fold) LDLR protein. In HepG2-PCSK9-knockout cells, ASGR1 silencing led to ∼2-fold higher levels of LDLR protein and DiI (1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate)-LDL uptake associated with ∼9-fold increased cell-surface LDLR. Overexpression of WT-ASGR1/2 primarily reduced levels of immature non-O-glycosylated LDLR (∼110 kDa), whereas the triple Ala-mutant of Gln240/Trp244/Glu253 (characterized by loss of carbohydrate binding) reduced expression of the mature form of LDLR (∼150 kDa), suggesting that ASGR1 binds the LDLR in both a sugar-dependent and -independent fashion. The protease furin cleaves ASGR1 at the R KM K 103 ↓ motif into a secreted form, likely resulting in a loss of function on LDLR. Altogether, we demonstrate that LDLR is the first example of a liver-receptor ligand of ASGR1. We conclude that silencing of ASGR1 and PCSK9 may lead to higher LDL uptake by hepatocytes, thereby providing a novel approach to further reduce LDL cholesterol levels.

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“…This suggested that the atheroprotective effects of ASGR1 LOF extended beyond reduction of serum LDLc and could implicate extrahepatic functions of ASGR1, e.g. , in macrophages ( 36 ).…”

Section: Discussionmentioning

confidence: 99%

Asialoglycoprotein receptor 1 is a novel PCSK9-independent ligand of liver LDLR cleaved by furin

Susan‐Resiga

Girard

Essalmani

et al. 2021

Journal of Biological Chemistry

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“…There is growing recognition that native NEU enzymes may play important roles in inflammation and immune cells. (22,30,86,87) We propose that further investigation of the role of these enzymes in B cell regulation is needed. 90) Bacterially-produced enzymes may also be contaminated with LPS, which we observed could alter CD22 clustering.…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

“…Exogenous NEU reagents have helped establish the importance of CD22-sialoside interactions; however, there has been very little work to investigate the role of native NEU enzymes on this system. There are four human NEU isoenzymes (hNEU): NEU1, NEU2, NEU3, and NEU4 and they have important cellular functions and roles in health and disease, (21) including atherosclerosis, (22) malignancy, (23)(24)(25) and neurodegenerative diseases. (26)(27)(28)(29) Together with glycosyl transferase enzymes (GTs), NEU regulate sialic acid content in cells.…”

Section: Introductionmentioning

confidence: 99%

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NEU1 and NEU3 enzymes alter CD22 organization on B cells

Tran

Chakraberty

et al. 2021

Preprint

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The B cell membrane expresses sialic acid binding Immunoglobulin-like lectins, also called Siglecs, that are important for modulating immune response. Siglecs have interactions with sialoglycoproteins found on the same membrane (cis ligands) that result in homotypic and heterotypic receptor clusters. The regulation and organization of these clusters, and their effect on cell activation, is not clearly understood. We investigated the role of human neuraminidase enzymes, NEU1 and NEU3, on the clustering of CD22 on B cells using confocal microscopy. We observed that native NEU1 and NEU3 activity influence the cluster size of CD22. Using single-particle tracking, we observed that NEU3 activity increased the lateral mobility of CD22, which was in contrast to the effect of exogenous bacterial NEU enzymes. Moreover, we show that native NEU1 and NEU3 activity influenced cellular Ca2+ levels, supporting a role for these enzymes in regulating B cell activation. Our results establish a role for native NEU activity in modulating CD22 organization and function on B cells.

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“…reported that two human ASGR1 -deletion variants found in Iceland, resulting in truncated proteins, likely inactive, are associated with a modest ∼10-14% reduction in LDLc, yet with a significant ∼34% reduced risk of coronary artery disease (12). This suggested that the atheroprotective effects of ASGR1 LOF extended beyond reduction of serum LDLc and could implicate, extrahepatic functions of ASGR1, e.g., in macrophages (36).…”

Section: Discussionmentioning

confidence: 99%

Asialoglycoprotein receptor 1 is a novel PCSK9-independent ligand of liver LDLR that is shed by Furin

Susan‐Resiga

Girard

Essalmani

et al. 2021

Preprint

View full text Add to dashboard Cite

The hepatic carbohydrate-recognizing asialoglycoprotein receptor (ASGR1) mediates the endocytosis/lysosomal degradation of desialylated glycoproteins following binding to terminal galactose/N-acetylgalactosamine. Human heterozygote-carriers of ASGR1-deletions exhibited ~34% lower risk of coronary artery disease and ~10-14% non-HDL-cholesterol reduction. Since PCSK9 is a major degrader of LDLR, we examined the regulation of LDLR and/or PCSK9 by ASGR1. We investigated the role of endogenous/overexpressed ASGR1 on LDLR degradation and functionality in nave HepG2 and HepG2-PCSK9-knockout cells by Western-blot and immunofluorescence. ASGR1, like PCSK9, targets LDLR and both interact with/enhance the degradation of the receptor independently. The lack of cooperativity between PCSK9 and ASGR1 on LDLR expression was confirmed in livers of wild-type (WT) versus Pcsk9-/- mice. ASGR1-knockdown in nave HepG2 cells significantly increased total (~1.2-fold) and cell-surface (~4-fold) LDLR protein. In HepG2-PCSK9-knockout cells ASGR1-silencing led to ~2-fold higher levels of LDLR protein and DiI-LDL uptake associated with ~4-fold increased cell-surface LDLR. Overexpression of WT-ASGR1 reduced primarily the immature non-O-glycosylated LDLR (~110 kDa), whereas the triple Gln240/Trp244/Glu253 Ala-mutant (loss of carbohydrate-binding) reduced the mature form of the LDLR (~150 kDa), suggesting that ASGR1 binds the LDLR in sugar-dependent and -independent fashion. Furin sheds ASGR1 at RKMK103 into a secreted form, likely resulting in a loss-of-function on LDLR. LDLR is the first example of a liver-receptor ligand of ASGR1. Additionally, we demonstrate that lack of ASGR1 enhances LDLR levels and DiI-LDL incorporation, independently of PCSK9. Overall, silencing of ASGR1 and PCSK9 may lead to higher LDL-uptake by hepatocytes, thereby providing a novel approach to further reduce LDL-cholesterol.

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Neuraminidases 1 and 3 Trigger Atherosclerosis by Desialylating Low‐Density Lipoproteins and Increasing Their Uptake by Macrophages

Cited by 45 publications

References 80 publications

Asialoglycoprotein receptor 1 is a novel PCSK9-independent ligand of liver LDLR cleaved by furin

Asialoglycoprotein receptor 1 is a novel PCSK9-independent ligand of liver LDLR cleaved by furin

NEU1 and NEU3 enzymes alter CD22 organization on B cells

Asialoglycoprotein receptor 1 is a novel PCSK9-independent ligand of liver LDLR that is shed by Furin

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