RESUMO
Nucleos(t)ide analogs (NAs) cannot completely suppress the risk of hepatocellular carcinoma (HCC) in patients with chronic hepatitis B (CHB). This study aimed to identify the risk factors for HCC development in naïve CHB patients treated with current NA. Patients receiving NA (n = 905) were recruited retrospectively from the 17 hospitals of the Japanese Red Cross Liver Study Group. All treatment-naïve patients had been receiving current NA continuously for more than 1 year until the end of the follow-up. We analyzed the accuracy of predictive risk score using the area under receiver operating characteristic curve. The albumin-bilirubin (ALBI) score was significantly improved by NA therapy (-0.171 ± 0.396; p < 0.001 at Week 48). A total of 72 (8.0%) patients developed HCC over a median follow-up of 6.2 (1.03-15.7) years. An independent predictive factor of HCC development was older age, cirrhosis, lower platelet counts at baseline and ALBI score, and alpha-fetoprotein (AFP) at 1 year after NA therapy according to multivariate analysis. The accuracy was assessed using the PAGE-B, mPAGE-B, aMAP, APA-B, and REAL-B scores that included these factors. Discrimination was generally acceptable for these models. aMAP and REAL-B demonstrated high discrimination with 0.866/0.862 and 0.833/0.859 for 3- and 5-year prediction from the status of 1 year after NA therapy, respectively. Baseline age and platelet count, as well as ALBI and AFP one year after NA, were useful for stratifying carcinogenesis risk. The aMAP and REAL-B scores were validated with high accuracy in Japanese CHB patients.
Assuntos
Carcinoma Hepatocelular , Hepatite B Crônica , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/epidemiologia , Carcinoma Hepatocelular/etiologia , Carcinoma Hepatocelular/tratamento farmacológico , alfa-Fetoproteínas , Neoplasias Hepáticas/epidemiologia , Neoplasias Hepáticas/etiologia , Hepatite B Crônica/complicações , Hepatite B Crônica/tratamento farmacológico , Hepatite B Crônica/patologia , Antivirais/uso terapêutico , Estudos Retrospectivos , Fatores de Risco , AlbuminasRESUMO
BACKGROUND: It is unclear whether the fibrosis 4 index (FIB-4), a marker of liver fibrosis, at baseline and change in FIB-4 after sustained virological response (SVR) is associated with incident hepatocellular carcinoma (HCC) risk. In this study, we examined the association of incident HCC risk with baseline FIB-4 and sustained high FIB-4 (>3.25) at any time point after SVR. METHODS: A total of 3823 patients who received direct-acting antiviral treatment and achieved SVR were enrolled. The FIB-4 was measured 24 weeks after the end of direct-acting antiviral treatment and achievement of SVR (SVR24), and 1, 2, and 3 years after SVR24, after which subsequent HCC development was investigated. RESULTS: In patients with an FIB-4 >3.25 at SVR24 and 1, 2, and 3 years after SVR24, subsequent HCC development was significantly higher than in those with an FIB-4 ≤3.25 at each point. The rates of HCC development 1, 2, 3, and 4 years after SVR24 were significantly higher in patients with sustained FIB-4 >3.25 than in those whose FIB-4 decreased to ≤3.25 (5.4%, 9.2%, 11.7%, and 16.0%, respectively, vs 2.2%, 3.1%, 3.7%, and 4.4%; Pâ <â .001). The adjusted hazard ratios (95% confidence intervals) for an FIB-4 >3.25 at SVR24 and 1, 2, and 3 years later were 3.38 (2.4-4.8), 2.95 (1.9-4.7), 2.62 (1.3-5.1), and 3.37 (1.4-9.8), respectively. CONCLUSIONS: The FIB-4 could be used to assess HCC development risk at any time after SVR, and changes in FIB-4 were associated with changes in the HCC development risk. Repeated assessments of FIB-4 could serve as a prognostic indicator of a high-risk HCC cohort that may require more intensive HCC surveillance strategy.
Assuntos
Carcinoma Hepatocelular , Hepatite C Crônica , Neoplasias Hepáticas , Antivirais/uso terapêutico , Carcinoma Hepatocelular/epidemiologia , Hepacivirus , Hepatite C Crônica/complicações , Hepatite C Crônica/tratamento farmacológico , Humanos , Cirrose Hepática/tratamento farmacológico , Cirrose Hepática/epidemiologia , Neoplasias Hepáticas/epidemiologia , Fatores de Risco , Resposta Viral SustentadaRESUMO
The real-world virological efficacy and safety of interferon-free direct-acting antiviral (DAA) therapy with sofosbuvir (SOF) and velpatasvir (VEL) were assessed in hepatitis C virus (HCV) genotype 1- and 2-infected patients with decompensated cirrhosis. A total of 65 patients with HCV-related decompensated cirrhosis (Child-Pugh score of 7 points or more) who were treated with the SOF/VEL regimen were enrolled. The sustained virological response (SVR) rate and safety profile were analyzed. SVR was defined as undetectable serum HCV RNA at 12 weeks after the end of treatment (SVR12). The percentages of patients with undetectable HCV RNA at 4, 8, and 12 weeks after the start of therapy were 81.2% (95% confidence interval [CI], 69.5-89.9) (52/64), 98.4% (95% CI, 91.2-100.0) (60/61), and 98.5% (95% CI, 91.7-100.0) (64/65), respectively. The overall SVR rate was 92.3% (95% CI, 83.0-97.5) (60/65). Albumin-bilirubin (ALBI) scores decreased during and after treatment (p < 0.001), and there were significant differences between baseline and end of treatment and between baseline and SVR12. Subgroup analyses showed no significant differences in SVR rates according to patient age, sex, HCV genotype (subtype), Child-Pugh classification, modified ALBI grade, presence of ascites, presence of hepatic coma, or history of hepatocellular carcinoma. In all subpopulations, the SVR rates were higher than 80%. There were no severe adverse events associated with the treatment. The SOF/VEL regimen showed good virological efficacy and acceptable safety even in patients with HCV-related decompensated cirrhosis.
Assuntos
Antivirais/uso terapêutico , Carbamatos/uso terapêutico , Hepacivirus/efeitos dos fármacos , Hepatite C Crônica/tratamento farmacológico , Compostos Heterocíclicos de 4 ou mais Anéis/uso terapêutico , Cirrose Hepática/virologia , Sofosbuvir/uso terapêutico , Idoso , Combinação de Medicamentos , Feminino , Genótipo , Hepacivirus/genética , Hepatite C Crônica/complicações , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Resposta Viral SustentadaRESUMO
AIM: The present study aimed to determine the real-world efficacy and safety of the non-structural protein (NS)5A inhibitor elbasvir (EBR) combined with the NS3/4A protease inhibitor grazoprevir (GZR) in patients with hepatitis C virus (HCV) genotype 1 (GT1) infection. METHODS: This study retrospectively evaluated the rate of sustained virologic response at 12 weeks post-treatment (SVR12) and the safety of EBR/GZR treatment in 159 men and 194 women with a median age of 72 years, and it assessed factors associated with the SVR12 rate. The attending physicians were responsible for selecting candidate patients for EBR/GZR in this retrospective study. RESULTS: Treatment outcomes for EBR/GZR were good in direct-acting antiviral (DAA)-naïve patients, of whom 99.4% achieved SVR. Of 353 patients, 10 (2.9%) had treatment failure. Of these patients, eight previously underwent DAA therapy, and the remaining two had NS5A-L31/Y93 double mutation. The SVR rate was 50% (8/16 patients) in patients who previously underwent DAA therapy, and 18.2% (2/11 patients) in patients with NS5A-L31/Y93 double mutation. On multivariate logistic regression analysis, NS5A-Y31/Y93 double mutation (odds ratio 356.3; 95% confidence interval, 23.91-16 940; P < 0.0001) was identified as an independent predictor of treatment failure. No serious adverse events were observed with EBR/GZR therapy. CONCLUSIONS: The SVR rate of EBR/GZR would have been 100% in patients without either a history of DAA therapy or double mutation. This combination of drugs could be safely given and is, thus, considered a highly useful first-line treatment for DAA-naïve patients with HCV.
RESUMO
AIM: To evaluate the virologic responses and clinical course of daclatasvir plus asunaprevir treatment in non-hemodialysis (non-HD) and hemodialysis (HD) patients infected with genotype 1 hepatitis C virus (HCV). METHODS: A total of 1113 non-HD patients and 67 HD patients were assessed. To evaluate pretreatment factors contributing to sustained virological response at 12 weeks (SVR12), univariate and multivariate analyses were carried out. To adjust for differences in patient background, propensity score matching was undertaken. RESULTS: The overall SVR12 rates were 91.6% in non-HD patients and 95.5% in HD patients. Compared with non-HD patients, HD patients were younger, were more likely to be male, were less likely to have received interferon-based pretreatment, had a lower viral load, and had lower levels of alanine transaminase, hemoglobin, and α-fetoprotein. Multivariate analysis revealed that viral load, α-fetoprotein, L31 substitution negative, and Y93 substitution negative were independent predictive factors for SVR12 in non-HD patients. The proportion of patients with undetectable HCV-RNA during the initial 4 weeks was significantly higher in HD patients than in non-HD patients. The SVR12 rate was clearly higher in HD patients than in non-HD patients, although the difference was not statistically significant. After propensity score matching to adjust for viral load, α-fetoprotein, L31 substitution, and Y93 substitution, these trends disappeared. CONCLUSIONS: For treatment of HCV genotype 1 infection, daclatasvir plus asunaprevir is useful not only in non-HD patients but also in HD patients. Viral load, α-fetoprotein levels, L31 substitution, and Y93 substitution influence treatment course and outcome.
RESUMO
Diacylglycerol kinase (DGK) plays an important role in phosphoinositide signaling cascade by regulating the intracellular level of diacylglycerol and phosphatidic acid. The DGK family is involved in various pathophysiological responses that are mediated through unique binding partners in different tissues and cells. In this study, we identified a small GTPase effector protein, IQGAP1, as a novel DGKζ-associated complex protein. A bacterial endotoxin, lipopolysaccharide (LPS), facilitated the complex formation in macrophages. Both proteins co-localized at the edge and phagocytic cup of the cell. Furthermore, RNA interference-mediated knockdown of DGKζ or IQGAP1 impaired LPS-induced Rac1 activation. Primary macrophages derived from DGKζ(-/-) mice attenuated LPS-induced phagocytosis of bacteria. These results suggest that DGKζ is involved in IQGAP1/Rac1-mediated phagocytosis upon LPS stimulation in macrophages.
Assuntos
Diacilglicerol Quinase/metabolismo , Macrófagos/imunologia , Neuropeptídeos/metabolismo , Fagocitose , Proteínas rac de Ligação ao GTP/metabolismo , Proteínas Ativadoras de ras GTPase/metabolismo , Animais , Células Cultivadas , Diacilglicerol Quinase/genética , Humanos , Lipopolissacarídeos/imunologia , Ativação de Macrófagos , Camundongos , Camundongos Endogâmicos C57BL , Proteínas rac1 de Ligação ao GTPRESUMO
Diacylglycerol kinase (DGK) is involved in the regulation of lipid-mediated signal transduction through the metabolism of a second messenger diacylglycerol. Of the DGK family, DGKζ, which contains a nuclear localization signal, localizes mainly to the nucleus but translocates to the cytoplasm under pathological conditions. However, the detailed mechanism of translocation and its functional significance remain unclear. To elucidate these issues, we used a proteomic approach to search for protein targets that interact with DGKζ. Results show that nucleosome assembly protein (NAP) 1-like 1 (NAP1L1) and NAP1-like 4 (NAP1L4) are identified as novel DGKζ binding partners. NAP1Ls constitutively shuttle between the nucleus and the cytoplasm in transfected HEK293 cells. The molecular interaction of DGKζ and NAP1Ls prohibits nuclear import of DGKζ because binding of NAP1Ls to DGKζ blocks import carrier proteins, Qip1 and NPI1, to interact with DGKζ, leading to cytoplasmic tethering of DGKζ. In addition, overexpression of NAP1Ls exerts a protective effect against doxorubicin-induced cytotoxicity. These findings suggest that NAP1Ls are involved in a novel molecular basis for the regulation of nucleocytoplasmic shuttling of DGKζ and provide a clue to examine functional significance of its translocation under pathological conditions.
Assuntos
Diacilglicerol Quinase/metabolismo , Carioferinas/metabolismo , Proteínas Nucleares/metabolismo , Proteína 1 de Modelagem do Nucleossomo/metabolismo , Nucleossomos/metabolismo , Animais , Células COS , Células Cultivadas , Chlorocebus aethiops , Citoplasma/genética , Citoplasma/metabolismo , Células HEK293 , Células HeLa , Humanos , Proteínas Nucleares/genética , Proteína 1 de Modelagem do Nucleossomo/genética , Nucleossomos/genética , Ligação Proteica/genética , Ligação Proteica/fisiologia , Transporte Proteico , Proteômica/métodos , Transdução de Sinais , Células Tumorais Cultivadas , alfa Carioferinas/metabolismoRESUMO
The identification of patients with advanced fibrosis who do not need any further hepatocellular carcinoma (HCC) surveillance after the eradication of hepatitis C is pivotal. In this study, we developed a simple serum-based risk model that could identify patients with low-risk HCC. This was a nationwide multicenter study involving 16 Hospitals in Japan. Patients with advanced fibrosis (1,325 in a derivation cohort and 508 in a validation cohort) who achieved sustained virological responses at 24 weeks after treatment (SVR24) were enrolled. The HCC risk model at any point after SVR24 and its change were evaluated, and subsequent HCC development was analyzed. Based on the multivariable analysis, patients fulfilling all of the factors (GAF4 criteria: gamma-glutamyl transferase < 28 IU/L, alpha-fetoprotein < 4.0 ng/mL, and Fibrosis-4 Index < 4.28) were classified as low-risk and others were classified as high-risk. When patients were stratified at the SVR24, and 1 year, and 2 years after SVR24, subsequent HCC development was significantly lower in low-risk patients (0.5-1.1 per 100 person-years in the derivation cohort and 0.9-1.1 per 100 person-years in the validation cohort) than in high-risk patients at each point. HCC risk from 1 year after SVR24 decreased in patients whose risk improved from high-risk to low-risk (HCC incidence: 0.6 per 100 person-years [hazard ratio (HR) = 0.163 in the derivation cohort] and 1.3 per 100 person-years [HR = 0.239 in the validation cohort]) than in those with sustained high risk. Conclusion: The HCC risk model based on simple serum markers at any point after SVR and its change can identify patients with advanced fibrosis who are at low HCC risk, and these patients may be able to reduce HCC surveillance.
Assuntos
Carcinoma Hepatocelular , Hepatite C Crônica , Hepatite C , Neoplasias Hepáticas , Antivirais/uso terapêutico , Carcinoma Hepatocelular/diagnóstico , Hepacivirus , Hepatite C/complicações , Hepatite C Crônica/complicações , Humanos , Cirrose Hepática/complicações , Neoplasias Hepáticas/diagnóstico , Medição de Risco , Fatores de RiscoRESUMO
BACKGROUND AND AIM: The pathogenic process underlying the development of hepatocellular carcinoma (HCC) is not yet clear in patients with hepatitis C virus (HCV) who have received direct-acting antiviral (DAA) therapy and achieved sustained virological response (SVR). This study validated a composite predictive model for HCC in these patients. METHODS: This study included 3058 patients in whom HCV was eradicated with DAA therapy. After DAAs recommendation for surveillance (ADRES) score, which is based on sex, FIB-4 index, and α-fetoprotein, was used as a composite predictive model for HCC development. RESULTS: The 1-, 3-, and 5-year cumulative incidence rates of HCC were 0.9, 4.5, and 15.2%, respectively. Multivariate analysis with Cox proportional hazards models showed that male sex (hazard ratio [HR], 2.646; 95% confidence interval [CI], 1.790-3.911), FIB-4 index >3.25 (HR, 2.891; 95% CI, 1.947-4.293), and α-fetoprotein >5 ng/mL (HR, 2.835; 95% CI, 1.914-4.200) are independently associated with HCC development. The incidence of HCC differed significantly by ADRES score (P < 0.001). Cox proportional hazards models showed that compared to the ADRES score 0 group, the HR for HCC development was 2.947 (95% CI, 1.367-6.354) in the ADRES score 1 group, 9.171 (95% CI, 4.339-19.380) in the ADRES score 2 group, and 20.630 (95% CI, 8.641-49.230) in the ADRES score 3 group. ADRES score had superior predictive power for HCC development compared with the FIB-4 index and α-fetoprotein according to time-dependent receiver operating characteristic analysis. CONCLUSION: The ADRES score is useful for predicting HCC development after SVR.
RESUMO
The effects of geometric properties of membranes on the structure of the phospholipase C-delta1 (PLC-delta1) pleckstrin homology (PH) domain were investigated using solid state (13)C NMR spectroscopy. Conformations of the PLC-delta1 PH domain at the surfaces of multilamellar vesicles (MLV), small unilamellar vesicles (SUV), and micelles were examined to evaluate the effects of membrane curvature on the PH domain. An increase in curvature of the water-hydrophobic layer interface hinders membrane-penetration of the amphipathic alpha2-helix of the PH domain that assists the membrane-association of the PH domain dominated by the phosphatidylinositol 4,5-bisphosphate (PIP(2)) specific lipid binding site. The solid state (13)C NMR signal of Ala88 located at the alpha2-helix indicates that the conformation of the alpha2-helix at the micelle surface is similar to the solution conformation and significantly different from those at the MLV and SUV surfaces which were characterized by membrane-penetration and re-orientation. The signal of Ala112 which flanks the C-terminus of the beta5/beta6 loop that includes the alpha2-helix, showed downfield displacement with decrease in the interface curvature of the micelles, SUV and MLV. This reveals that the conformation of the C-terminus of the beta5/beta6 loop connecting the beta-sandwich core containing the PIP(2) binding site and the amphipathic alpha2-helix is sensitive to alterations of the curvature of lipid bilayer surface. It is likely that these alterations in the conformation of the PLC-delta1 PH domain contribute to the regulatory mechanisms of the intracellular localization of PLC-delta1 in a manner dependent upon the structure of the molecular complex containing PIP(2).
Assuntos
Bicamadas Lipídicas/química , Fosfatidilinositol 4,5-Difosfato/química , Fosfolipase C delta/química , Animais , Sítios de Ligação/fisiologia , Proteínas Sanguíneas , Fosfoproteínas , Estrutura Secundária de Proteína/fisiologia , Estrutura Terciária de Proteína/fisiologia , Ratos , Homologia Estrutural de ProteínaRESUMO
There is a class of GTPase activating proteins for the Rho family GTPases (RhoGAPs) that contain the steroidogenic acute regulatory protein (STAR)-related lipid transfer (START) domain. In mammals three genes encode such proteins and they are designated START-GAP1-3 or deleted in liver cancer 1-3 (DLC1-3). In this study, we examined the intracellular localization and roles of START-GAP1/DLC1 in cell motility. Immunofluorescence microscopic analysis of NRK cells and HeLa cells revealed that START-GAP1 was localized in focal adhesions. Amino acid residues 265-459 of START-GAP1 were found to be necessary for focal adhesion targeting and we name the region "the focal adhesion-targeting (FAT) domain." It was previously known that ectopic expression of START-GAP1 induced cell rounding. We demonstrated that the FAT domain of START-GAP1 was partially required for this morphological change. Furthermore, expression of this domain in HeLa cells resulted in dissociation of endogenous START-GAP1 from focal adhesions as a dominant negative modulator, reducing cell migration and spreading. Taken together, START-GAP1 is targeted to focal adhesions via the FAT domain and regulates actin rearrangement through down-regulation of active RhoA and Cdc42. Its absence from focal adhesions could, therefore, cause abnormal cell motility and spreading.
Assuntos
Movimento Celular , Forma Celular , Adesões Focais/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Proteínas Supressoras de Tumor/fisiologia , Movimento Celular/fisiologia , Forma Celular/fisiologia , Células Cultivadas , Adesões Focais/fisiologia , Proteínas Ativadoras de GTPase , Células HeLa , Humanos , Modelos Biológicos , Estrutura Terciária de Proteína/genética , Estrutura Terciária de Proteína/fisiologia , Distribuição Tecidual , Transfecção , Proteínas Supressoras de Tumor/química , Proteínas Supressoras de Tumor/genética , Proteína cdc42 de Ligação ao GTP/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismoRESUMO
Gastroepiploic artery aneurysm (GEAA) is very rare.1 Furthermore, most GEAA cases are diagnosed after their rupture. We report a case of asymptomatic GEAA. The patient was a 61-year-old man. Sonography (US) revealed a 2-cm anechoic mass in the epigastrium near the anterior abdominal wall. Color Doppler US and contrast-enhanced US showed arterial flow within the mass leading to the diagnosisof visceral artery aneurysm. CT and angiography confirmed the diagnosis of right GEAA, and the aneurysm was treated successfully with embolization. Follow-up US 6 months later confirmed the absence of blood flow within the lesion.
Assuntos
Aneurisma/diagnóstico por imagem , Artéria Gastroepiploica/diagnóstico por imagem , Dor Abdominal/etiologia , Aneurisma/complicações , Meios de Contraste , Diagnóstico Diferencial , Seguimentos , Humanos , Aumento da Imagem/métodos , Masculino , Pessoa de Meia-Idade , Ultrassonografia Doppler em Cores/métodosRESUMO
Hepatic hemangiomas are usually asymptomatic and very rarely produce abdominal symptoms. We report a painful 10 × 9 cm hemangioma situated at the hepatic surface of segment 6. The lesion showed a heterogeneous internal structure, composed irregularly of hyperechoic and hypoechoic areas, and it also showed weak posterior echo enhancement. Contrast-enhanced US showed the so-called fill-in pattern, leading to the diagnosis of hepatic hemangioma. The patient's abdomen showed no other abnormal findings, which stressed the relationship between the hemangioma and the patient's symptoms. When the diagnosis of hepatic hemangioma is conclusive, surgical therapy is indicated only in patients with severe symptoms. Our patient was considered to be a candidate for enucleation of the lesion. Histopathologically, the lesion included no areas of hemorrhage or necrosis, and the patient's abdominal pain was likely due to distension of the liver capsule. After surgery, the patient was completely free of symptoms, and enucleation was considered to be appropriate.
RESUMO
Nucleos(t)ide analogs (NA) suppress hepatitis B virus (HBV) replication and reduce the risk of hepatocellular carcinoma (HCC). However, NA cannot suppress carcinogenesis completely in patients with chronic hepatitis B. The aims of this study were to identify risk factors for HCC and develop a refined carcinogenesis prediction model. Patients receiving NA therapy (n = 1,183) were recruited retrospectively from the 16 hospitals. All patients had been receiving NA continuously for more than 1 year until the end of the follow-up. During a median follow-up of 4.9 (1.0-12.9) years, 52 (4.4%) patients developed HCC. A multivariate analysis revealed that male gender, older age, lower platelet counts at the baseline, and detectable HBV DNA during NA therapy were independent predictive factors of HCC development. The PAGE-B score was calculated by using these factors. 240 (20.3%), 661 (55.9%), and 282 (23.8%) patients were classified into low-, intermediate-, and high-risk groups, respectively. In the intermediate- and high-risk group, detectable HBV DNA was significantly associated with a higher risk of HCC development compared with continuously undetectable HBV DNA, respectively (HR 3.338; 95% CI 1.045-10.66/HR 3.191; 95% CI 1.543-6.597). PAGE-B-DNA, which is the combined PAGE-B and HBV DNA status, was valuable for a more refined stratification of PAGE-B.
Assuntos
Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/virologia , DNA Viral/análise , Vírus da Hepatite B/genética , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/virologia , Nucleotídeos/uso terapêutico , Carcinoma Hepatocelular/diagnóstico , Carcinoma Hepatocelular/epidemiologia , Feminino , Humanos , Incidência , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/epidemiologia , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Análise de Regressão , Fatores de RiscoRESUMO
Phosphorylation of phospholipase C-delta(1) (PLC-delta(1)) in vitro and in vivo was investigated. Of the serine/threonine kinases tested, protein kinase C (PKC) phosphorylated the serine residue(s) of bacterially expressed PLC-delta(1) most potently. It was also demonstrated that PLC-delta(1) directly bound PKC-alpha via its pleckstrin homology (PH) domain. Using deletion mutants of PLC-delta(1) and synthetic peptides, Ser35 in the PH domain was defined as the PKC mediated in vitro phosphorylation site of PLC-delta(1). In vitro phosphorylation of PLC-delta(1) by PKC stimulated [(3)H]PtdIns(4,5)P(2) hydrolyzing activity and [(3)H]Ins(1,4,5)P(3)-binding of the PLC-delta(1). On the other hand, endogenous PLC-delta(1) was constitutively phosphorylated and phosphoamino acid analysis revealed that major phosphorylation sites were threonine residues in quiescent cells. The phosphorylation level and the species of phosphoamino acid were not changed by various stimuli such as PMA, EGF, NGF, and forskolin. Using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, we determined that Thr209 of PLC-delta(1) is one of the constitutively phosphorylated sites in quiescent cells. The PLC activity was potentiated when constitutively phosphorylated PLC-delta(1) was dephosphorylated by endogenous phosphatase(s) in vitro. Additionally, coexpression with PKC-alpha reduced serine phosphorylation of PLC-delta(1) detected by an anti-phosphoserine antibody and PLC-delta(1)-dependent basal production of inositol phosphates in NIH-3T3 cells, suggesting PKC-alpha activates phosphatase or inactivates another kinase involved in PLC-delta(1) serine phosphorylation to modulate the PLC-delta(1) activity in vivo. Taken together, these results suggest that PLC-delta(1) has multiple phosphorylation sites and phosphorylation status of PLC-delta(1) regulates its activity positively or negatively depends on the phosphorylation sites.
Assuntos
Fosfolipase C delta/metabolismo , Sequência de Aminoácidos , Animais , Células COS , Chlorocebus aethiops , Inositol 1,4,5-Trifosfato/metabolismo , Camundongos , Dados de Sequência Molecular , Proteínas Mutantes/química , Proteínas Mutantes/metabolismo , Células NIH 3T3 , Peptídeos/química , Peptídeos/metabolismo , Fosfolipase C delta/química , Fosforilação , Fosfosserina/metabolismo , Ligação Proteica , Proteína Quinase C-alfa/metabolismo , Estrutura Terciária de Proteína , Ratos , Proteínas Recombinantes de Fusão/metabolismoRESUMO
Dynamin 2 has been reported to be implicated in phagocytosis. However, the mode of action of dynamin is poorly understood. In this study, we examined whether dynamin 2 participates in actin assembly during phagocytosis in Sertoli cells. In the presence of dynasore, a dynamin inhibitor, phagocytosis was reduced by 60-70% in Sertoli cells and macrophages. Scanning electron microscopy revealed that Sertoli cells treated with dynasore were unable to form phagocytic cups. In addition, dysfunction of dynamin 2 reduced both actin polymerization and recruitment of actin and dynamin 2 to phosphatidylinositol (4,5) bisphosphate [PI(4,5)P(2)]-containing liposomes. The formation of dynamin 2-positive ruffles of Sertoli cells was decreased by 60-70% by sequestering PI(4,5)P(2) either by expression of PH domain of PLCdelta or treatment with neomycin. These results strongly suggest that dynamin 2 is involved in actin dynamics and the formation of dynamin 2-positive ruffles during phagocytosis.
Assuntos
Actinas/metabolismo , Dinamina II/fisiologia , Fagocitose , Células de Sertoli/imunologia , Actinas/efeitos dos fármacos , Animais , Dinamina II/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Masculino , Fagocitose/efeitos dos fármacos , Fosfatidilinositol 4,5-Difosfato/farmacologia , Ratos , Células de Sertoli/enzimologiaRESUMO
START-GAP2, also termed as DLC2, is a START domain-containing RhoGAP and a negative regulator of RhoA and Cdc42. Although it was reported as a tumor suppresser gene product, the molecular basis for function of START-GAP2 remains to be clarified. Here, we demonstrate that START-GAP2 is localized in focal adhesions through a "FAT (focal adhesion targeting)" region in the N-terminal half. START-GAP2 competes with START-GAP1/DLC1, another START domain-containing RhoGAP, in focal adhesion targeting. Moreover, the C-terminus of tensin2, one of focal adhesion components and reported to bind START-GAP1, also directly interacts with START-GAP2. These results suggest that START-GAP2 and START-GAP1 share the same molecular mechanism in targeting to focal adhesions.
Assuntos
Adesões Focais/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Animais , Células HeLa , Humanos , Camundongos , Proteínas dos Microfilamentos/genética , Proteínas dos Microfilamentos/metabolismo , Monoéster Fosfórico Hidrolases/genética , Monoéster Fosfórico Hidrolases/metabolismo , Estrutura Terciária de Proteína/genética , Tensinas , Proteínas Supressoras de Tumor/genéticaRESUMO
BACKGROUND: We aimed to describe the real-world efficacy and safety of combination therapy with ledipasvir and sofosbuvir (LDV/SOF) for chronic hepatitis C virus (HCV) genotype 1 (GT1) infection. METHODS: This retrospective analysis of a prospective, nationwide, multicenter registry included GT1-infected patients treated with LDV/SOF for 12 weeks. We assessed the rate of sustained virological response at 12 weeks post-treatment (SVR12), incidence of adverse events, and serum markers of hepatocellular carcinoma (HCC). RESULTS: Among the 1461 patients included (mean age, 69 years; 29.5% aged > 75 years; cirrhosis, 23.8%; history of treatment for HCC, 10.9%), the overall SVR12 rate was 98.4% (1438/1461). Factors associated with treatment failure were cirrhosis (odds ratio, 4.19; p = 0.014) and resistance-associated substitutions (RASs) in NS5A at baseline (odds ratio, 7.78; p = 0.0004). The SVR12 rate in patients with cirrhosis and NS5A RASs was 93.0% compared to 100% in patients without cirrhosis or NS5A RASs. In patients with SVR, the levels of alpha-fetoprotein (AFP), AFP-L3, and Mac-2 binding protein glycosylation isomer (M2BPGi) decreased from baseline to end of treatment (from 13.4 ± 37.6 to 6.0 ± 10.6 ng/mL, p < 0.0001; from 2.2 ± 4.9 to 1.5 ± 6.3%, p < 0.005; and from 3.6 ± 3.7 to 2.0 ± 3.5 cut-off index, p < 0.0001; respectively). Adverse events were rare and not associated with age. No decrease in estimated glomerular filtration rate was observed in patients with baseline chronic kidney disease stage 3. CONCLUSIONS: LDV/SOF therapy is highly effective and safe in elderly Japanese patients with HCV GT1, even in the presence of cirrhosis or NS5A RASs. Patients with SVR may have a lower risk of HCC.
Assuntos
Antivirais/uso terapêutico , Benzimidazóis/uso terapêutico , Fluorenos/uso terapêutico , Hepacivirus/efeitos dos fármacos , Hepacivirus/genética , Hepatite C Crônica/tratamento farmacológico , Hepatite C Crônica/virologia , Sofosbuvir/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Antivirais/efeitos adversos , Benzimidazóis/efeitos adversos , Carcinoma Hepatocelular/sangue , Carcinoma Hepatocelular/etiologia , Quimioterapia Combinada , Feminino , Fluorenos/efeitos adversos , Hepatite C Crônica/sangue , Hepatite C Crônica/complicações , Humanos , Japão/epidemiologia , Cirrose Hepática/tratamento farmacológico , Cirrose Hepática/etiologia , Cirrose Hepática/patologia , Neoplasias Hepáticas/sangue , Neoplasias Hepáticas/etiologia , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Estudos Prospectivos , Cruz Vermelha , Estudos Retrospectivos , Risco , Sofosbuvir/efeitos adversos , Resposta Viral Sustentada , Falha de Tratamento , Proteínas não Estruturais Virais/análise , Adulto Jovem , alfa-Fetoproteínas/análiseRESUMO
The delta family phosphoinositide (PI)-specific phospholipase C (PLC) are most fundamental forms of eukaryotic PI-PLCs. Despite the presence of lipid targeting domains such as the PH domain and C2 domain, the isoforms are also found in the cytoplasm and nucleus as well as at the plasma membrane. The isoforms have sequences or regions that can serve as a nuclear localization signal (NLS) and a nuclear export signal (NES). Their intracellular localization differs from one isoform to another, presumably due to the difference in the transport equilibrium balanced by the strength of the two signals of each isoform. Even for a particular isoform, its intracellular localization seems to vary during the cell cycle. As an example, PLCdelta(1), which is generally found at the plasma membrane and in the cytoplasm of quiescent cells, localizes to discrete nuclear structures in the G(1)/S boundary of the cell cycle. This may be at least partly due to an increase in intracellular Ca(2+), since Ca(2+) facilitates the formation of a nuclear transport complex comprised of PLCdelta(1) and importin beta1, a carrier molecule for the nuclear import. PLCdelta(1) as well as PLCdelta(4) may play a pivotal role in controlling the initiation of DNA synthesis in S phase. Spatio-temporal changes in the levels of PtdIns(4,5)P(2) seem to be another major determinant for the localization and regulation of the delta isoforms. High nuclear PtdIns(4,5)P(2) levels are associated with the G(1)/S phases. After entering M phase, PtdIns(4,5)P(2) synthesis at sites of cell division occurs and PLCs seem to localize to the cleavage furrow during cytokinesis. Coordinated translocation of PLCs with the cell cycle or with stress responses may result in changes in intra-nuclear environments and local membrane architectures that modulate proliferation and differentiation. In this review, recent findings regarding the molecular machineries and mechanisms of the nucleocytoplasmic shuttling as well as roles in the cell cycle progression of the delta isoforms of PLC will be discussed.
Assuntos
Ciclo Celular/fisiologia , Núcleo Celular/metabolismo , Fosfatidilinositol Diacilglicerol-Liase/metabolismo , Fosfatidilinositóis/metabolismo , Diester Fosfórico Hidrolases/metabolismo , Transporte Proteico/fisiologia , Transdução de Sinais/fisiologia , Animais , Proteínas de Ciclo Celular/metabolismo , Humanos , Líquido Intracelular/metabolismo , Bicamadas Lipídicas/metabolismo , Fosfoinositídeo Fosfolipase C , Fosfolipase C deltaRESUMO
The membrane binding affinity of the pleckstrin homology (PH) domain of phospholipase C (PLC)-delta1 was investigated using a vesicle coprecipitation assay and the structure of the membrane-associated PH domain was probed using solid-state (13)C NMR spectroscopy. Twenty per cent phosphatidylserine (PS) in the membrane caused a moderate but significant reduction of the membrane binding affinity of the PH domain despite the predicted electrostatic attraction between the PH domain and the head groups of PS. Solid-state NMR spectra of the PH domain bound to the phosphatidylcholine (PC)/PS/phosphatidylinositol 4,5-bisphosphate (PIP(2)) (75 : 20 : 5) vesicle indicated loss of the interaction between the amphipathic alpha2-helix of the PH domain and the interface region of the membrane which was previously reported for the PH domain bound to PC/PIP(2) (95 : 5) vesicles. Characteristic local conformations in the vicinity of Ala88 and Ala112 induced by the hydrophobic interaction between the alpha2-helix and the membrane interface were lost in the structure of the PH domain at the surface of the PC/PS/PIP(2) vesicle, and consequently the structure becomes identical to the solution structure of the PH domain bound to d-myo-inositol 1,4,5-trisphosphate. These local structural changes reduce the membrane binding affinity of the PH domain. The effects of PS on the PH domain were reversed by NaCl and MgCl(2), suggesting that the effects are caused by electrostatic interaction between the protein and PS. These results generally suggest that the structure and function relationships among PLCs and other peripheral membrane proteins that have similar PH domains would be affected by the local lipid composition of membranes.