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1.
Sci Rep ; 14(1): 10864, 2024 05 13.
Article in English | MEDLINE | ID: mdl-38740815

ABSTRACT

Lysyl oxidase-like 2 (LOXL2) mediates the crosslinking of extracellular collagen, reflecting qualitative changes in liver fibrosis. This study aimed to validate the utility of serum LOXL2 levels as a predictive biomarker for the development of hepatocellular carcinoma (HCC) in patients with hepatitis C virus (HCV) infection who achieved a sustained virological response (SVR). This retrospective study included 137 patients with chronic HCV infection without history of HCC development and who achieved SVR via direct-acting antiviral therapy. Median LOXL2 levels decreased significantly after SVR achievement (pre-Tx, 2.33 ng/mL; post-Tx, 1.31 ng/mL, p < 0.001). Post-Tx LOXL2 levels, fibrosis-4 index, platelet counts, Wisteria floribunda agglutinin-positive human Mac-2 binding protein levels, and alpha-fetoprotein (AFP) levels were identified as independent predictive factors for post-SVR HCC development in the univariate analysis. The incidence of post-SVR HCC development was significantly higher in patients with post-Tx LOXL2 levels ≥ 2.08 ng/mL and AFP levels ≥ 5.0 ng/mL than in patients with elevated levels of either marker or with lower marker levels. Serum LOXL2 levels can serve as a predictive biomarker for HCC development after achieving SVR. The combination of serum LOXL2 and AFP levels provides robust risk stratification for HCC development after SVR, suggesting an enhanced surveillance strategy.


Subject(s)
Amino Acid Oxidoreductases , Antiviral Agents , Carcinoma, Hepatocellular , Hepatitis C, Chronic , Liver Neoplasms , Sustained Virologic Response , Humans , Carcinoma, Hepatocellular/blood , Carcinoma, Hepatocellular/virology , Liver Neoplasms/blood , Liver Neoplasms/virology , Male , Female , Middle Aged , Amino Acid Oxidoreductases/blood , Retrospective Studies , Hepatitis C, Chronic/complications , Hepatitis C, Chronic/drug therapy , Hepatitis C, Chronic/blood , Hepatitis C, Chronic/virology , Aged , Antiviral Agents/therapeutic use , Hepacivirus , Biomarkers, Tumor/blood , alpha-Fetoproteins/metabolism , alpha-Fetoproteins/analysis , Adult
2.
Free Radic Biol Med ; 212: 199-206, 2024 02 20.
Article in English | MEDLINE | ID: mdl-38103659

ABSTRACT

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease, leading to liver steatosis, fibrosis, and hepatocellular carcinoma (HCC). Despite the accumulation of clinical data showing the impact of amino acid substitutions at positions 70 (R70Q/H) and/or 91 (L91M) in the HCV core protein in progressive liver diseases, including HCC, the underlying mechanisms have not been elucidated. We analyzed 72 liver biopsy specimens from patients with chronic HCV genotype 1b (HCV-1b) infection prior to antiviral treatment. Levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and nuclear factor erythroid 2-related factor 2 (NRF2) in the nucleus were quantified using liver tissue immunohistochemistry. The effects of amino acid substitutions in the HCV core region on hepatocellular oxidative stress were investigated using wild-type or double-mutant (R70Q/H+L91M) HCV-1b core transfection and stable expression in human hepatoma HuH-7 cells. Overall, 24, 19, 11, and 18 patients had the wild-type, R70Q/H, L91M, and R70Q/H+L91M genotypes, respectively, in the HCV core. A significantly higher accumulation of hepatocellular 8-OHdG and a lower NRF2/8-OHdG ratio were observed in patients with R70Q/H+L91M than in those with the wild-type disease. Increased levels of intracellular superoxide and hydrogen peroxide in the cytoplasm and mitochondria, mRNA expression of enzymes generating oxidative stress, and nuclear expression of nicotinamide adenine dinucleotide phosphate oxidase 4 were augmented in cells treated with R70Q+L91M. HCV core proteins harboring either or both substitutions of R70Q/H or L91M enhanced hepatocellular oxidative stress in vivo and in vitro. These amino acid substitutions may affect HCC development by enhancing hepatic oxidative stress in patients with chronic HCV-1b infection.


Subject(s)
Carcinoma, Hepatocellular , Hepatitis C, Chronic , Hepatitis C , Liver Neoplasms , Humans , Carcinoma, Hepatocellular/pathology , Hepacivirus/genetics , Liver Neoplasms/pathology , Amino Acid Substitution , NF-E2-Related Factor 2/genetics , Hepatitis C/genetics , Hepatitis C, Chronic/genetics , Oxidative Stress/genetics , 8-Hydroxy-2'-Deoxyguanosine , Viral Core Proteins/genetics , Viral Core Proteins/pharmacology , Viral Core Proteins/therapeutic use , Genotype
3.
Mol Cell Biochem ; 2023 Oct 30.
Article in English | MEDLINE | ID: mdl-37902885

ABSTRACT

BACKGROUND & AIMS: Hepatic stellate cells (HSCs) play an essential role in liver fibrogenesis. The induction of cellular senescence has been reported to inhibit HSC activation. Previously, we demonstrated that CWHM12, a small molecule arginine-glycine-aspartic acid (RGD) peptidomimetic compound, inhibits HSC activation. This study investigated whether the inhibitory effects of CWHM12 on HSCs affected cellular senescence. METHODS: The immortalized human HSC lines, LX-2 and TWNT-1, were used to evaluate the effects of CWHM12 on cellular senescence via the disruption of RGD-mediated binding to integrins. RESULTS: CWHM12 induces cell cycle arrest, senescence-associated beta-galactosidase activity, acquisition of senescence-associated secretory phenotype (SASP), and expression of senescence-associated proteins in HSCs. Further experiments revealed that the phosphorylation of AKT and murine double minute 2 (MDM2) was involved in the effects of CWHM12, and the inhibition of AKT phosphorylation reversed these effects of CWHM12 on HSCs. CONCLUSIONS: Pharmacological inhibition of RGD-mediated integrin binding induces senescence in activated HSCs.

4.
PLoS Pathog ; 19(8): e1011591, 2023 08.
Article in English | MEDLINE | ID: mdl-37585449

ABSTRACT

Hepatitis C virus (HCV) is a pathogen characterized not only by its persistent infection leading to the development of cirrhosis and hepatocellular carcinoma (HCC), but also by metabolic disorders such as lipid and iron dysregulation. Elevated iron load is commonly observed in the livers of patients with chronic hepatitis C, and hepatic iron overload is a highly profibrogenic and carcinogenic factor that increases the risk of HCC. However, the underlying mechanisms of elevated iron accumulation in HCV-infected livers remain to be fully elucidated. Here, we observed iron accumulation in cells and liver tissues under HCV infection and in mice expressing viral proteins from recombinant adenoviruses. We established two molecular mechanisms that contribute to increased iron load in cells caused by HCV infection. One is the transcriptional induction of hepcidin, the key hormone for modulating iron homeostasis. The transcription factor cAMP-responsive element-binding protein hepatocyte specific (CREBH), which was activated by HCV infection, not only directly recognizes the hepcidin promoter but also induces bone morphogenetic protein 6 (BMP6) expression, resulting in an activated BMP-SMAD pathway that enhances hepcidin promoter activity. The other is post-translational regulation of the iron-exporting membrane protein ferroportin 1 (FPN1), which is cleaved between residues Cys284 and Ala285 in the intracytoplasmic loop region of the central portion mediated by HCV NS3-4A serine protease. We propose that host transcriptional activation triggered by endoplasmic reticulum stress and FPN1 cleavage by viral protease work in concert to impair iron efflux, leading to iron accumulation in HCV-infected cells.


Subject(s)
Carcinoma, Hepatocellular , Hepatitis C , Liver Neoplasms , Animals , Mice , Hepacivirus/physiology , Hepatitis C/metabolism , Hepcidins/genetics , Hepcidins/metabolism , Iron/metabolism , Transcriptional Activation , Up-Regulation
5.
Biochim Biophys Acta Mol Basis Dis ; 1869(7): 166750, 2023 10.
Article in English | MEDLINE | ID: mdl-37268254

ABSTRACT

BACKGROUND & AIMS: Ferroptosis is a form of regulated cell death and its promotion in hepatic stellate cells (HSCs) attenuates liver fibrosis. Statins, which are 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, may induce ferroptosis via the downregulation of glutathione peroxidase 4 (GPX4) by inhibiting the mevalonate pathway. However, little evidence is available regarding the association between statins and ferroptosis. Therefore, we investigated the association between statins and ferroptosis in HSCs. METHODS: Two human HSC cell lines, LX-2 and TWNT-1, were treated with simvastatin, an HMG-CoA reductase inhibitor. Mevalonic acid (MVA), farnesyl pyrophosphate (FPP), and geranylgeranyl pyrophosphate (GGPP) were used to determine the involvement of the mevalonate pathway. We performed a detailed analysis of the ferroptosis signaling pathway. We also investigated human liver tissue samples from patients with nonalcoholic steatohepatitis to clarify the effect of statins on GPX4 expression. RESULTS: Simvastatin reduced cell mortality and inhibited HSCs activation, accompanied by iron accumulation, oxidative stress, lipid peroxidation, and reduced GPX4 protein expression. These results indicate that simvastatin inhibits HSCs activation by promoting ferroptosis. Furthermore, treatment with MVA, FPP, or GGPP attenuated simvastatin-induced ferroptosis. These results suggest that simvastatin promotes ferroptosis in HSCs by inhibiting the mevalonate pathway. In human liver tissue samples, statins downregulated the expression of GPX4 in HSCs without affecting hepatocytes. CONCLUSIONS: Simvastatin inhibits the activation of HSCs by regulating the ferroptosis signaling pathway.


Subject(s)
Ferroptosis , Hydroxymethylglutaryl-CoA Reductase Inhibitors , Humans , Simvastatin/pharmacology , Hydroxymethylglutaryl-CoA Reductase Inhibitors/pharmacology , Hepatic Stellate Cells/metabolism , Mevalonic Acid/metabolism , Mevalonic Acid/pharmacology , Signal Transduction
6.
J Autoimmun ; 136: 103027, 2023 04.
Article in English | MEDLINE | ID: mdl-36996700

ABSTRACT

Primary biliary cholangitis (PBC) is a classic autoimmune disease due to the loss of tolerance to self-antigens. Bile acids (BA) reportedly play a major role in biliary inflammation and/or in the modulation of dysregulated immune responses in PBC. Several murine models have indicated that molecular mimicry plays a role in autoimmune cholangitis; however, they have all been limited by the relative failure to develop hepatic fibrosis. We hypothesized that species-specific differences in the BA composition between mice and humans were the primary reason for this limited pathology. Here, we aimed to study the impact of human-like hydrophobic BA composition on the development of autoimmune cholangitis and hepatic fibrosis. We took advantage of a unique construct, Cyp2c70/Cyp2a12 double knockout (DKO) mice, which have human-like BA composition, and immunized them with a well-defined mimic of the major mitochondrial autoantigen of PBC, namely 2-octynoic acid (2OA). 2OA-treated DKO mice were significantly exacerbated portal inflammation and bile duct damage with increased Th1 cytokines/chemokines at 8 weeks post-initial immunization. Most importantly, there was clear progression of hepatic fibrosis and increased expression of hepatic fibrosis-related genes. Interestingly, these mice demonstrated increased serum BA concentrations and decreased biliary BA concentrations; hepatic BA levels did not increase because of the upregulation of transporters responsible for the basolateral efflux of BA. Furthermore, cholangitis and hepatic fibrosis were more advanced at 24 weeks post-initial immunization. These results indicate that both the loss of tolerance and the effect of hydrophobic BA are essential for the progression of PBC.


Subject(s)
Autoimmune Diseases , Cholangitis , Liver Cirrhosis, Biliary , Humans , Animals , Mice , Bile Acids and Salts , Liver Cirrhosis , Inflammation , Autoantigens , Disease Models, Animal
7.
J Clin Med ; 12(6)2023 Mar 13.
Article in English | MEDLINE | ID: mdl-36983211

ABSTRACT

Rifaximin, a non-absorbable antibiotic, has been demonstrated to be effective against hepatic encephalopathy (HE); however, its efficacy on liver functional reserve remains unknown. Here, we evaluated the efficacy of rifaximin on the liver functional reserve and serological inflammation-based markers in patients with cirrhosis. A retrospective study was conducted on patients who received rifaximin for more than three months at our hospital between November 2016 and October 2021. The recurrence and grade of HE, serological ammonia levels, Child-Pugh score (CPS), and serological inflammation-based markers such as the neutrophil-lymphocyte ratio (NLR), lymphocyte-monocyte ratio (LMR), platelet-lymphocyte ratio (PLR), C-reactive protein (CRP), and CRP to albumin ratio (CAR) were evaluated. The correlations between serological inflammation-based markers and liver functional reserve were evaluated. HE grades, serum ammonia levels, and inflammation-based markers significantly improved at three months compared with those at baseline. Patients with improved albumin levels showed significantly higher CRP improvement rates at both 3 and 12 months. Patients with an improvement in CAR at 3 months demonstrated a significant improvement in CPS at 12 months. Rifaximin improved the liver functional reserve in patients with cirrhosis. Improvements in inflammation-based markers, particularly CRP and albumin, may be involved in this process.

8.
Intern Med ; 62(8): 1157-1166, 2023 Apr 15.
Article in English | MEDLINE | ID: mdl-36070948

ABSTRACT

A 59-year-old woman presented to our hospital with liver dysfunction. Imaging revealed multiple lesions in the liver. The patient was diagnosed with peliosis hepatis using percutaneous and laparoscopic biopsies. However, her condition worsened with the appearance of new, obvious mass-forming lesions. Therefore, she underwent a second percutaneous biopsy of these lesions and was diagnosed with hepatic angiosarcoma. Her condition progressed rapidly, and she died two weeks after the diagnosis. Diagnosis of hepatic angiosarcoma in the early stages is difficult. It should be noted that hepatic angiosarcoma may be associated with the development of peliosis hepatis.


Subject(s)
Hemangiosarcoma , Liver Neoplasms , Peliosis Hepatis , Female , Humans , Middle Aged , Peliosis Hepatis/diagnosis , Peliosis Hepatis/diagnostic imaging , Hemangiosarcoma/diagnostic imaging , Liver/pathology , Liver Neoplasms/diagnosis , Liver Neoplasms/diagnostic imaging
9.
Cell Signal ; 99: 110437, 2022 11.
Article in English | MEDLINE | ID: mdl-35970425

ABSTRACT

BACKGROUND & AIMS: Liver fibrosis characterizes advanced chronic liver disease, and persistent activation of hepatic stellate cells (HSCs) is the primary cause of excessive hepatic fibrogenesis. CWHM12, an analog of the arginine-glycine-aspartic acid (RGD) amino acid sequence found in specific integrins, improves liver fibrosis; however, the detailed mechanisms remain unclear. This study aimed to clarify the cell signaling mechanisms of CWHM12 in activated HSCs. METHODS: Immortalized human HSC lines, LX-2 and TWNT-1, were used to evaluate the effects of CWHM12 on intracellular signaling via the disruption of RGD-binding integrins. RESULTS: CWHM12 strongly promoted phosphorylation and inhibited the nuclear accumulation of Yes-associated protein (YAP), which is a critical effector of the Hippo signaling pathway, leading to the inhibition of proliferation, suppression of viability, promotion of apoptosis, and induction of cell cycle arrest at the G1 phase in activated HSCs. Further investigations revealed that inhibition of TGF-ß was involved in the consequences of CWHM12. Moreover, CWHM12 suppressed focal adhesion kinase (FAK) phosphorylation; consequently, Src, phosphatidylinositol 3-kinase, pyruvate dehydrogenase kinase 1, and serine-threonine kinase phosphorylation led to the translocation of YAP. These favorable effects of CWHM12 on activated HSCs were reversed by inhibiting FAK. CONCLUSIONS: These results indicate that pharmacological inhibition of RGD-binding integrins suppresses activated HSCs by blocking the Hippo signaling pathway, a cellular response which may be valuable in the treatment of hepatic fibrosis.


Subject(s)
Hepatic Stellate Cells , Hippo Signaling Pathway , Arginine/metabolism , Aspartic Acid/metabolism , Aspartic Acid/pharmacology , Aspartic Acid/therapeutic use , Focal Adhesion Protein-Tyrosine Kinases/metabolism , Glycine/metabolism , Hepatic Stellate Cells/metabolism , Humans , Integrins/metabolism , Liver Cirrhosis/metabolism , Oligopeptides/metabolism , Oligopeptides/pharmacology , Oligopeptides/therapeutic use , Phosphatidylinositols/metabolism , Phosphatidylinositols/pharmacology , Phosphatidylinositols/therapeutic use , Protein Serine-Threonine Kinases , Pyruvate Dehydrogenase Acetyl-Transferring Kinase , Transforming Growth Factor beta/metabolism , YAP-Signaling Proteins
10.
Hepatol Commun ; 6(8): 1855-1869, 2022 08.
Article in English | MEDLINE | ID: mdl-35344290

ABSTRACT

Despite reports of hepatocellular carcinoma (HCC) in patients with chronic hepatitis C virus (HCV) infection after achieving sustained virological response (SVR), only few studies have demonstrated the incidence of other (non-HCC) malignancies. This study aimed to clarify the incidence, survival probability, and factors associated with malignancy, especially non-HCC malignancies, in patients with chronic HCV infection after achieving SVR. In this retrospective study, records of 3580 patients with chronic HCV infection who achieved SVR following direct-acting antiviral (DAA) treatment were analyzed. The cumulative post-SVR incidence of non-HCC malignancies was 0.9%, 3.1%, and 6.8% at 1, 3, and 5 years, respectively. The survival probability for patients with non-HCC malignancies was 99.1%, 78.8%, and 60.2% at 1, 3, and 5 years, respectively, and the rate was significantly lower than that for patients with HCC. The Cox proportional hazards regression model identified Mac-2-binding protein glycan isomer (M2BPGi) cutoff index (COI) ≥ 1.90 at baseline and ≥ 1.50 at 12 weeks following DAA treatment as significant and independent factors associated with the post-SVR incidence of non-HCC malignancies. Furthermore, patients with either M2BPGi COI ≥ 1.90 at baseline or M2BPGi COI ≥ 1.50 at SVR12 had a significantly higher risk of post-SVR incidence of non-HCC malignancies than of HCC. Conclusion: M2BPGi measurements at baseline and SVR12 may help predict the post-SVR incidence of non-HCC malignancies in patients with chronic HCV infection who achieved SVR following DAA treatment. Early identification of these patients is critical to prolong patient survival.


Subject(s)
Carcinoma, Hepatocellular , Hepatitis C, Chronic , Liver Neoplasms , Antiviral Agents/therapeutic use , Carcinoma, Hepatocellular/epidemiology , Hepatitis C, Chronic/drug therapy , Humans , Liver Neoplasms/epidemiology , Polysaccharides/therapeutic use , Retrospective Studies
11.
Clin Case Rep ; 9(8): e04696, 2021 Aug.
Article in English | MEDLINE | ID: mdl-34466252

ABSTRACT

This report highlights azathioprine-induced severe myelosuppression in the patient with NUDT15 minor variant. This case report is particularly instructive because several typical symptoms are the clues to this critical adverse drug reaction.

12.
Eur J Immunol ; 51(6): 1519-1530, 2021 06.
Article in English | MEDLINE | ID: mdl-33710617

ABSTRACT

Ursodeoxycholic acid (UDCA) is the primary treatment for primary biliary cholangitis (PBC), but its mechanism of action remains unclear. Studies suggest that UDCA enhances NF erythroid 2-related factor 2 (NFE2L2) expression and that the interaction between IFN-γ and C-X3-C motif chemokine ligand 1 (CX3CL1) facilitates biliary inflammation in PBC. Therefore, we examined the effects of UDCA on the expression of IFN-γ and CX3CL1 in in vitro and in vivo PBC models such as human liver tissue, a murine model, cell lines, and isolated human intrahepatic biliary epithelial cells (IHBECs). We observed a significant decrease in IFN-γ mRNA levels and positive correlations between IFN-γ and CX3CL1 mRNA levels post-UDCA treatment in PBC livers. NFE2L2-mediated transcriptional activation was significantly enhanced in UDCA-treated Jurkat cells. In 2-octynoic acid-immunized mice, IFN-γ production by liver-infiltrating T cells was dependent on NFE2L2 activation. IFN-γ significantly and dose-dependentlyinduced CX3CL1 expression, which was significantly decreased in HuCC-T1 cells and IHBECs upon UDCA treatment. These results suggest that UDCA-induced suppression of IFN-γ and CX3CL1 production attenuates the chemotactic and adhesive abilities of liver-infiltrating T cells in PBC.


Subject(s)
Chemokine CX3CL1/metabolism , Cholagogues and Choleretics/therapeutic use , Epithelial Cells/physiology , Interferon-gamma/metabolism , Liver Cirrhosis, Biliary/drug therapy , Liver/immunology , T-Lymphocytes/immunology , Ursodeoxycholic Acid/therapeutic use , Adult , Aged , Aged, 80 and over , Chemotaxis , Female , Humans , Immunosuppression Therapy , Interferon-gamma/genetics , Jurkat Cells , Liver/pathology , Liver Cirrhosis, Biliary/immunology , Male , Middle Aged
13.
Hepatol Res ; 51(1): 80-89, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33080094

ABSTRACT

AIM: The ursodeoxycholic acid response score (URS) can predict the biochemical response to 12 months of ursodeoxycholic acid (UDCA) treatment in patients with primary biliary cholangitis (PBC). We investigated the relationship between the URS and the histopathological features before and after UDCA treatment. METHODS: Patients with PBC (n = 126) were examined for the association between the probability of response (POR) to UDCA based on the URS formulas and clinicopathological features. Furthermore, 30 patients were examined for the association between the POR and pathological changes. RESULTS: The POR area under the receiver operating characteristic curve (AUROC) for predicting the biochemical response to UDCA was 0.861. The PORs of stage 1 in the Nakanuma system and grade 0 in the CK7 grading in hepatocytes were significantly higher than those of stage 3 and grade 3, respectively. The AUROCs for the prediction of stage ≥2, stage ≥3 and stage 4 in the Nakanuma system at pretreatment were 0.592, 0.710 and 0.817, respectively. The AUROCs for the prediction of grade ≥1, grade ≥2 and grade 3 in the CK7 hepatocyte grading were 0.741, 0.824 and 0.970, respectively. Furthermore, the AUROC for predicting the histological stage progression after UDCA treatment in the Scheuer classification and the Nakanuma system were 0.712 and 0.799, respectively. CONCLUSIONS: The URS not only predicts the biochemical response, but also reflects the Nakanuma system and the CK7 hepatocyte grading at pretreatment. This scoring system can identify an inadequate histological response to UDCA treatment in the Scheuer classification and the Nakanuma system.

15.
mSphere ; 5(1)2020 01 15.
Article in English | MEDLINE | ID: mdl-31941812

ABSTRACT

The pathogenic fungus Aspergillus fumigatus contains galactomannans localized on the surface layer of its cell walls, which are involved in various biological processes. Galactomannans comprise α-(1→2)-/α-(1→6)-mannan and ß-(1→5)-/ß-(1→6)-galactofuranosyl chains. We previously revealed that GfsA is a ß-galactofuranoside ß-(1→5)-galactofuranosyltransferase involved in the biosynthesis of ß-(1→5)-galactofuranosyl chains. In this study, we clarified the biosynthesis of ß-(1→5)-galactofuranosyl chains in A. fumigatus Two paralogs exist within A. fumigatus: GfsB and GfsC. We show that GfsB and GfsC, in addition to GfsA, are ß-galactofuranoside ß-(1→5)-galactofuranosyltransferases by biochemical and genetic analyses. GfsA, GfsB, and GfsC can synthesize ß-(1→5)-galactofuranosyl oligomers at up to lengths of 7, 3, and 5 galactofuranoses within an established in vitro highly efficient assay of galactofuranosyltransferase activity. Structural analyses of galactomannans extracted from ΔgfsB, ΔgfsC, ΔgfsAC, and ΔgfsABC strains revealed that GfsA and GfsC synthesized all ß-(1→5)-galactofuranosyl residues of fungal-type and O-mannose-type galactomannans and that GfsB exhibited limited function in A. fumigatus The loss of ß-(1→5)-galactofuranosyl residues decreased the hyphal growth rate and conidium formation ability and increased the abnormal hyphal branching structure and cell surface hydrophobicity, but this loss is dispensable for sensitivity to antifungal agents and virulence toward immunocompromised mice.IMPORTANCE ß-(1→5)-Galactofuranosyl residues are widely distributed in the subphylum Pezizomycotina of the phylum Ascomycota. Pezizomycotina includes many plant and animal pathogens. Although the structure of ß-(1→5)-galactofuranosyl residues of galactomannans in filamentous fungi was discovered long ago, it remains unclear which enzyme is responsible for biosynthesis of this glycan. Fungal cell wall formation processes are complicated, and information concerning glycosyltransferases is essential for understanding them. In this study, we showed that GfsA and GfsC are responsible for the biosynthesis of all ß-(1→5)-galactofuranosyl residues of fungal-type and O-mannose-type galactomannans. The data presented here indicate that ß-(1→5)-galactofuranosyl residues are involved in cell growth, conidiation, polarity, and cell surface hydrophobicity. Our new understanding of ß-(1→5)-galactofuranosyl residue biosynthesis provides important novel insights into the formation of the complex cell wall structure and the virulence of the members of the subphylum Pezizomycotina.


Subject(s)
Aspergillus fumigatus/enzymology , Mannans/biosynthesis , Mannans/chemistry , Mannose/chemistry , Animals , Aspergillus fumigatus/genetics , Cell Wall/chemistry , Cell Wall/metabolism , Galactose/analogs & derivatives , Glycosyltransferases/metabolism , Hyphae , Mannose/biosynthesis , Mice , Virulence
16.
Sci Rep ; 8(1): 16918, 2018 11 16.
Article in English | MEDLINE | ID: mdl-30446686

ABSTRACT

Fungal-type galactomannan (FTGM) is a polysaccharide composed of α-(1 → 2)-/α-(1 → 6)-mannosyl and ß-(1 → 5)-/ß-(1 → 6)-galactofuranosyl residues located at the outer cell wall of the human pathogenic fungus Aspergillus fumigatus. FTGM contains a linear α-mannan structure called core-mannan composed of 9 or 10 α-(1 → 2)-mannotetraose units jointed by α-(1 → 6)-linkages. However, the enzymes involved in core-mannan biosynthesis remain unknown. We speculated that two putative α-1,2-mannosyltransferase genes in A. fumigatus, Afu5g02740/AFUB_051270 (here termed core-mannan synthase A [CmsA]) and Afu5g12160/AFUB_059750 (CmsB) are involved in FTGM core-mannan biosynthesis. We constructed recombinant proteins for CmsA and detected robust mannosyltransferase activity using the chemically synthesized substrate p-nitrophenyl α-D-mannopyranoside as an acceptor. Analyses of CmsA enzymatic product revealed that CmsA possesses the capacity to transfer a mannopyranoside to the C-2 position of α-mannose. CmsA could also transfer a mannose residue to α-(1 → 2)-mannobiose and α-(1 → 6)-mannobiose and showed a 31-fold higher specific activity toward α-(1 → 6)-mannobiose than toward α-(1 → 2)-mannobiose. Proton nuclear magnetic resonance (1H-NMR) spectroscopy and gel filtration chromatography of isolated FTGM revealed that core-mannan structures were drastically altered and shortened in disruptant A. fumigatus strains ∆cmsA, ∆cmsB, and ∆cmsA∆cmsB. Disruption of cmsA or cmsB resulted in severely repressed hyphal extension, abnormal branching hyphae, formation of a balloon structure in hyphae, and decreased conidia formation. The normal wild type core-mannan structure and developmental phenotype were restored by the complementation of cmsA and cmsB in the corresponding disruptant strains. These findings indicate that both CmsA, an α-1,2-mannosyltransferase, and CmsB, a putative mannosyltransferase, are involved in FTGM biosynthesis.


Subject(s)
Aspergillus fumigatus/physiology , Mannans/metabolism , Mannosyltransferases/metabolism , Fungal Proteins/genetics , Fungal Proteins/metabolism , Galactose/analogs & derivatives , Gene Deletion , Phenotype
17.
Nihon Shokakibyo Gakkai Zasshi ; 115(10): 914-922, 2018.
Article in Japanese | MEDLINE | ID: mdl-30305573

ABSTRACT

A 51-year-old Brazilian female who had IgD-lambda type multiple myeloma presented with epigastralgia and obstructive jaundice during her follow-up. Contrast-enhanced computed tomography (CT) showed an enhanced mass of 25mm in the pancreatic head, and endoscopic retrograde cholangiopancreatography revealed smooth stenoses in the lower bile duct and main pancreatic duct (MPD) of the head. We diagnosed the patient with extramedullary pancreatic metastasis of multiple myelomas. Plastic stents were endoscopically placed into both the common bile duct and MPD. One week later, she suffered a repeat episode of epigastralgia. A subsequent CT scan showed obstructive pancreatitis due to another mass, 30mm in size, emerging rapidly in the pancreatic body. Pancreatitis improved after we replaced the plastic stent with a longer one so that the distal end reached beyond the stenosis at the MPD of the body. Although both the tumors were treated with radiotherapy and showed temporary reduction, the patient died 1 month later due to progression of the disease. While cases involving obstructive pancreatitis induced by extramedullary pancreatic metastasis of multiple myelomas are very rare, it is crucial that such patients are rapidly diagnosed and treated.


Subject(s)
Immunoglobulin D/metabolism , Multiple Myeloma/diagnosis , Pancreatic Neoplasms/secondary , Pancreatitis/pathology , Cholangiopancreatography, Endoscopic Retrograde , Female , Humans , Middle Aged , Pancreatic Ducts , Pancreatic Neoplasms/diagnosis , Stents
18.
Gut Liver ; 12(2): 201-207, 2018 Mar 15.
Article in English | MEDLINE | ID: mdl-29212314

ABSTRACT

BACKGROUND/AIMS: Changes in lipid profiles in patients infected with hepatitis C virus (HCV) during direct-acting antiviral therapy have been reported in recent years. However, the clinical aspects of disturbed lipid metabolism in chronic HCV infection have not been fully elucidated. METHODS: Dynamic changes in serum total, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol and apolipoprotein levels in patients infected with HCV genotype 1b were examined during combination therapy with daclatasvir (DCV) and asunaprevir (ASV). RESULTS: Total, LDL-, and HDL-cholesterol levels increased rapidly and persistently after week 4. Apolipoprotein (apo) A-I, apo B, apo C-II, and apo C-III levels were significantly higher at week 4 than at week 0. In contrast, apo A-II and apo E levels were significantly lower. The differences in LDL- and HDL-cholesterol levels were positively correlated with those of apo B and apo A-I, respectively. Interestingly, in patients with non-sustained virological response, these cholesterol levels decreased rapidly after viral breakthrough or viral relapse. Furthermore, similar changes were observed for apo A-I, apo B and apo C-III levels. CONCLUSIONS: Clearance of HCV using combination therapy with DCV and ASV results in rapid changes in serum lipid profiles, suggesting an influence of HCV infection on disturbed lipid metabolism.


Subject(s)
Hepacivirus/genetics , Hepatitis C, Chronic , Imidazoles/administration & dosage , Isoquinolines/administration & dosage , Lipoproteins/blood , Sulfonamides/administration & dosage , Aged , Antiviral Agents/administration & dosage , Carbamates , Cohort Studies , Drug Monitoring/methods , Drug Therapy, Combination/methods , Female , Hepatitis C, Chronic/blood , Hepatitis C, Chronic/drug therapy , Hepatitis C, Chronic/epidemiology , Hepatitis C, Chronic/virology , Humans , Japan/epidemiology , Lipid Metabolism/drug effects , Male , Middle Aged , Pyrrolidines , Retrospective Studies , Valine/analogs & derivatives
19.
Glycobiology ; 27(6): 568-581, 2017 06 01.
Article in English | MEDLINE | ID: mdl-28369326

ABSTRACT

Previously, we reported that GfsA is a novel galactofuranosyltransferase involved in the biosynthesis of O-glycan, the proper maintenance of fungal morphology, the formation of conidia and anti-fungal resistance in Aspergillus nidulans and A. fumigatus (Komachi Y et al., 2013. GfsA encodes a novel galactofuranosyltransferase involved in biosynthesis of galactofuranose antigen of O-glycan in Aspergillus nidulans and Aspergillus fumigatus. Mol. Microbiol. 90:1054-1073). In the present paper, to gain an in depth-understanding of the enzymatic functions of GfsA in A. fumigatus (AfGfsA), we established an in vitro assay to measure galactofuranosyltransferase activity using purified AfGfsA, UDP-α-d-galactofuranose as a sugar donor, and p-nitrophenyl-ß-d-galactofuranoside as an acceptor substrate. LC/MS, 1H-NMR and methylation analyses of the enzymatic products of AfGfsA revealed that this protein has the ability to transfer galactofuranose to the C-5 position of the ß-galactofuranose residue via a ß-linkage. AfGfsA requires a divalent cation of manganese for maximal activity and consumes UDP-α-d-galactofuranose as a sugar donor. Its optimal pH range is 6.5-7.5 and its optimal temperature range is 20-30°C. 1H-NMR, 13C-NMR and methylation analyses of fungal-type galactomannan extracted from the ∆AfgfsA strain revealed that AfGfsA is responsible for the biosynthesis of ß1,5-galactofuranose in the galactofuran side chain of fungal-type galactomannan. Based on these results, we conclude that AfGfsA acts as a UDP-α-d-galactofuranose: ß-d-galactofuranoside ß1,5-galactofuranosyltransferase in the biosynthetic pathway of galactomannans.


Subject(s)
Aspergillus fumigatus/enzymology , Fungal Polysaccharides/metabolism , Fungal Proteins/metabolism , Galactosyltransferases/metabolism , Fungal Polysaccharides/chemistry , Fungal Proteins/chemistry , Fungal Proteins/genetics , Furans/chemistry , Furans/metabolism , Galactose/analogs & derivatives , Galactosyltransferases/chemistry , Galactosyltransferases/genetics , Manganese/chemistry , Mannans/chemistry , Mannans/metabolism
20.
J Interferon Cytokine Res ; 35(12): 956-62, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26308703

ABSTRACT

The enhanced accumulation of hepatic progenitor cells (HPCs) is related to the risk of progression to hepatocellular carcinoma (HCC). Interferon (IFN) treatment reduces HCC risk in patients with chronic hepatitis C virus (HCV) infection. However, the underlying mechanisms remain unclear. The aim of this study was to examine the effects of IFN treatment on HPC activation in HCV patients. Immunohistochemical detection and computer-assisted quantitative image analyses of cytokeratin 7 (CK7) were performed to evaluate HPC activation in paired pre- and post-treatment liver biopsies from 18 HCV patients with sustained virological response (SVR) to IFN-based therapy and from 23 patients without SVR, as well as normal liver tissues obtained from surgical resection specimens of 10 patients. Pretreatment HCV livers showed increased CK7 immunoreactivity, compared with normal livers (HCV: median, 1.38%; normal: median, 0.69%, P=0.006). IFN treatment reduced hepatic CK7 immunoreactivity (median, 1.57% pre-IFN vs. 0.69% post-IFN, P=0.006) in SVR patients, but not in non-SVR patients. The development of HCC following IFN treatment was encountered in 3 non-SVR patients who showed high post-IFN treatment CK7 immunoreactivity (>4%). Successful IFN therapy can reverse enhanced HPC activation in HCV patients, which may contribute to the reduced risk of HCC development in these patients.


Subject(s)
Antiviral Agents/therapeutic use , Hepatitis C, Chronic/drug therapy , Hepatitis C, Chronic/metabolism , Interferons/therapeutic use , Stem Cells/drug effects , Stem Cells/metabolism , Adult , Aged , Animals , Antiviral Agents/pharmacology , Biomarkers , Biopsy , Carcinoma, Hepatocellular/etiology , Female , Hepatitis C, Chronic/diagnosis , Hepatitis C, Chronic/virology , Humans , Immunohistochemistry , Interferons/pharmacology , Keratin-7/metabolism , Liver Cirrhosis/etiology , Liver Cirrhosis/pathology , Liver Neoplasms/etiology , Male , Middle Aged , Retrospective Studies , Treatment Outcome
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