Association of hepatitis C virus envelope proteins with exosomes

Masciopinto, Francesca; Giovani, Cinzia; Campagnoli, Susanna; Galli-Stampino, Luisa; Colombatto, P.; Brunetto, Maurizia Rossana; Yen, T. S. Benedict; Houghton, Michael; Pileri, Piero; Abrignani, Sergio

doi:10.1002/eji.200424887

Cited by 187 publications

(194 citation statements)

References 36 publications

Supporting

Mentioning

175

Contrasting

Unclassified

Order By: Relevance

“…In addition, several reports suggest the presence of MHCcontaining exosome-like structures in rat [34] or human [35,36] blood. However, these reports have relied on dot blotting or Western blotting combined with ultracentrifugation to demonstrate the presence of MHC in exosomal pellets prepared from blood.…”

Section: Discussionmentioning

confidence: 99%

Circulating, soluble forms of major histocompatability complex antigens are not exosome‐associated

et al. 2006

View full text Add to dashboard Cite

In vitro studies have shown that soluble MHC (sMHC) released by cell lines is bound to nano-vesicles termed exosomes. It is thought that exosomes may represent the major reservoir of sMHC class I and II molecules in biological fluids. However, most studies have been confined to in vitro assays performed with cell lines. We show here that sMHC in the serum or plasma differs from exosome-bound sMHC in five ways: In contrast to exosome-associated sMHC, circulating sMHC is of low density, has a low apparent molecular mass (40-300 kDa) and is not detergent-labile. Moreover, the majority of MHC class II isoforms and MHC class I in blood are not physically linked and circulating HLA-DR is accessible to an antibody specific for the HLA-DR a-chain intracellular epitope, which is masked by its association with cellular or exosomal membranes. Finally, utilizing transcriptional activator of murine MHC class II (C2ta) promotermutant mice, we showed that the release of sMHC class II into the circulation is dependent on the C2ta pI promoter, but not pIII or pIV. This suggests that myeloid dendritic cells and/or macrophages, which preferentially use promoter pI of the C2ta gene, produce most of the sMHC class II found in the circulation.

show abstract

Section: Discussionmentioning

confidence: 99%

Circulating, soluble forms of major histocompatability complex antigens are not exosome‐associated

et al. 2006

View full text Add to dashboard Cite

show abstract

“…34,35 Nevertheless, differences in phospholipid molecular species composition and higher neutral lipid content distinguish LVPs between specific TRLs defined by their density. Interestingly, most LVPs resemble empty, nucleocapsid-free subviral particles, similar to recombinant subviral envelope particles produced in vitro, whereas nucleocapsid-containing LVPs are only a subset of the whole LVP ensemble.…”

Section: Discussionmentioning

confidence: 99%

High plasma level of nucleocapsid-free envelope glycoprotein-positive lipoproteins in hepatitis C patients

et al. 2012

View full text Add to dashboard Cite

Hepatitis C virus (HCV) particles associate viral and lipoprotein moieties to form hybrid lipoviral particles (LVPs). Cell culture-produced HCV (HCVcc) and ex vivo-characterized LVPs primarily differ by their apolipoprotein (apo) B content, which is low for HCVcc, but high for LVPs. Recombinant nucleocapsid-free subviral LVPs are assembled and secreted by apoB-producing cell lines. To determine whether such subviral particles circulate in HCV-infected individuals, LVPs complexed with immunoglobulin were precipitated with protein A from low-density plasma fractions of 36 hepatitis C patients, and their lipid content, apolipoprotein profile, and viral composition were determined. HCV RNA in LVPs was quantified and molar ratios of apoB and HCV genome copy number were calculated. LVPs lipidome from four patients was determined via electrospray ionization/tandem mass spectrometry. Protein A-purified LVPs contained at least the envelope glycoprotein E2 and E2-specific antibodies. LVPs were present in every patient and were characterized by high lipid content, presence of apolipoproteins characteristic of triglyceride-rich lipoproteins (TRLs), HCV RNA, and viral glycoprotein. Importantly, save for four patients, LVPs fractions contained large amounts of apoB, with on average more than 1 3 10 6 apoB molecules per HCV RNA genome. Because there is one apoB molecule per TRL, this ratio suggested that most LVPs are nucleocapsid-free, envelope glycoprotein-containing subviral particles. LVPs and TRLs had similar composition of triacylglycerol and phospholipid classes. Conclusion: LVPs are a mixed population of particles, comprising predominantly subviral particles that represent a distinct class of modified lipoproteins within the TRL family. (HEPATOLOGY 2012;56:39-48) H epatitis C virus (HCV) is a member of the Flaviviridae family and a major cause of chronic hepatitis often leading to liver cirrhosis and hepatocellular carcinoma. 1 Chronic hepatitis C is a complex disease associated with host metabolic modifications resulting in a unique metabolic syndrome including insulin resistance, liver steatosis, and hypobetalipoproteinemia. 2,3 The most striking link between HCV and lipids resides in the association of HCV particles with lipoproteins. 4,5 Indeed, HCV virions with a density <1.06 g/mL are associated with lipoproteins, thus forming hybrid particles known as lipoviral particles (LVPs). These low-density viral particles are globular, rich in triacylglycerol and total cholesterol (TChol) and contain the viral envelope glycoproteins and nucleocapsid (composed of HCV RNA and core protein). In addition, LVPs contain all the apolipoproteins (apo) that define the triacylglycerolrich lipoproteins (TRLs). Indeed, apolipoprotein (apo) B, apoE, apoCI, apoCII, and apoCIII, all of which characterize very low-density, intermediate-density, and low-density lipoproteins (VLDL, IDL, and LDL,

show abstract

Section: Isolation Of Cd81 From Serum and Plasmamentioning

confidence: 99%

“…Enrichment of exosomes was performed according to Masciopinto et al [25]. In this former study, the CD81 enriched exosomal fraction was identified by immunoblotting in the pellets from the fourth (p4) and -mainlythe fifth (p5) centrifugation fraction from plasma [25]. In the current study, differential centrifugation was performed at 200 g for 10 min (p1), at 500 g (p2), at 2000 g for 15 min (p3), at 10,000 g for 30 min (p4), and finally 100,000 g for 30 min (p5).…”

Section: Isolation Of Cd81 From Serum and Plasmamentioning

confidence: 99%

See 1 more Smart Citation

876 Soluble Serum Cd81 Is Elevated in Patients With Chronic Hepatitis C and Correlates With Alanine Aminotransferase Serum Activity

Welker¹,

Reichert²,

Susser³

et al. 2012

Journal of Hepatology

View full text Add to dashboard Cite

Aim: Cellular CD81 is a well characterized hepatitis C virus (HCV) entry factor, while the relevance of soluble exosomal CD81 in HCV pathogenesis is poorly defined. We performed a case-control study to investigate whether soluble CD81 in the exosomal serum fraction is associated with HCV replication and inflammatory activity.Patients and Methods: Four cohorts were investigated, patients with chronic hepatitis C (n = 37), patients with chronic HCV infection and persistently normal ALT levels (n = 24), patients with long term sustained virologic response (SVR, n = 7), and healthy volunteers (n = 23). Concentration of soluble CD81 was assessed semi-quantitatively after differential centrifugation ranging from 200 g to 100,000 g in the fifth centrifugation fraction by immunoblotting and densitometry.Results: Soluble CD81 was increased in patients with chronic hepatitis C compared to healthy subjects (p = 0.03) and cured patients (p = 0.017). Patients with chronic HCV infection and persistently normal ALT levels and patients with long term SVR had similar soluble CD81 levels as healthy controls (p.0.2). Overall, soluble CD81 levels were associated with ALT levels (r = 0.334, p = 0.016) and severe liver fibrosis (p = 0.027).Conclusion: CD81 is increased in the exosomal serum fraction in patients with chronic hepatitis C and appears to be associated with inflammatory activity and severity of fibrosis.

show abstract

Association of hepatitis C virus envelope proteins with exosomes

Cited by 187 publications

References 36 publications

Circulating, soluble forms of major histocompatability complex antigens are not exosome‐associated

Circulating, soluble forms of major histocompatability complex antigens are not exosome‐associated

High plasma level of nucleocapsid-free envelope glycoprotein-positive lipoproteins in hepatitis C patients

876 Soluble Serum Cd81 Is Elevated in Patients With Chronic Hepatitis C and Correlates With Alanine Aminotransferase Serum Activity

Contact Info

Product

Resources

About