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1.
Br J Haematol ; 2024 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-38981737

RESUMEN

There are limited data on the optimal choice of anticoagulation in multiple myeloma (MM) patients receiving immunomodulatory drugs (IMiDs). We conducted a propensity score-matched cohort study using the TriNetX database to compare the efficacy and safety of factor Xa inhibitors and warfarin in this patient population. Compared to warfarin, factor Xa inhibitors had a similar risk of deep vein thrombosis (hazard ratio [HR]: 1.11 [95% CI: 0.50-2.46]) or pulmonary embolism (HR: 1.08 [95% CI: 0.59-2.00]). There were no differences in the risk of gastrointestinal or intracranial bleeding. Factor Xa inhibitor-treated patients had lower all-cause mortality (HR: 0.56 [95% CI: 0.36-0.86]) compared with warfarin. These data suggest that factor Xa inhibitors had similar safety and efficacy compared with warfarin for MM patients on IMiDs.

2.
Oncology ; 102(6): 510-514, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38104536

RESUMEN

INTRODUCTION: Breast cancer is the most common cancer in women with a 5-year survival over 90%. However, anthracycline-based chemotherapy causes significant cardiotoxicity often requiring discontinuation of chemotherapeutic regimen among breast cancer survivors. We conducted a systematic review and meta-analysis to evaluate the efficacy of exercise training in mitigating anthracycline-related cardiotoxicity among women with breast cancer. METHODS: We searched PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, and Scopus databases. The outcomes of interest were left ventricular ejection fraction (LVEF), global longitudinal strain (GLS), early to atrial filling velocity (E/A) ratio, maximal oxygen consumption (VO2 max), and cardiac output (CO). We used the Cochrane risk-of-bias tool for randomized trials (RoB 2) to assess the risk of bias in individual studies. RESULTS: We identified a total of 596 articles with 5 trials included in the final analysis. Exercise training was associated with an increase in VO2 max compared with no exercise training (mean difference, 3.95 [95% CI, 0.63-7.26]; I2 = 99.68%). Other cardiovascular outcomes such as LVEF (mean difference, 1.76 [95% CI, -1.95 to 5.46]; I2 = 99.44%), GLS (mean difference, 0.30 [95% CI, -0.49 to 1.10]; I2 = 96.63%), E/A ratio (mean difference, 0.05 [95% CI, -0.05 to 0.15]; I2 = 94.16%), and CO (mean difference, 0.38 [95% CI, -0.91 to 1.66]; I2 = 99.73%) are similar between patients who underwent exercise training and those who did not. CONCLUSIONS: Exercise was associated with an improvement in maximal oxygen uptake among women with breast cancer receiving anthracycline-based chemotherapy.


Asunto(s)
Antraciclinas , Neoplasias de la Mama , Cardiotoxicidad , Humanos , Neoplasias de la Mama/tratamiento farmacológico , Femenino , Cardiotoxicidad/etiología , Cardiotoxicidad/prevención & control , Antraciclinas/efectos adversos , Ejercicio Físico , Consumo de Oxígeno/efectos de los fármacos , Volumen Sistólico/efectos de los fármacos , Terapia por Ejercicio/métodos
3.
J Gastroenterol Hepatol ; 39(5): 902-907, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38296226

RESUMEN

BACKGROUND AND AIM: Patients with type 2 diabetes mellitus (T2DM) have a higher risk of colorectal cancer (CRC), and those with diagnosed CRC have a poorer prognosis compared with individuals with normal glucose levels. The inhibition of sodium-glucose cotransporter 2 (SGLT2) channels has been associated with a reduction in tumor proliferation in preclinical studies. We aimed to investigate the impact of sodium-glucose cotransporter 2 inhibitors (SGLT2i) on the outcome of T2DM patients with colorectal cancer. METHODS: We performed a retrospective cohort study comprising adult patients with T2DM and colorectal adenocarcinoma. SGLT2i recipients were matched to non-SGLT2i recipients in a 1:1 ratio based on age, sex, and cancer stage. The primary outcome was overall survival (OS) and progression-free survival (PFS), and the secondary outcomes were previously reported serious adverse events associated with SGLT2i. RESULTS: We identified 1347 patients with T2DM and colorectal adenocarcinoma, from which 92 patients in the SGLT2i cohort were matched to the non-SGLT2i cohort. Compared to non-SGLT2i recipients, SGLT2i recipients had a higher rate of 5-year OS (86.2% [95% CI: 72.0-93.5] vs 62.3% [95% CI: 50.9-71.8], P = 0.013) and 5-year PFS (76.6% [95% CI: 60.7-86.7] vs 57.0% [95% CI: 46.2-66.4], P = 0.021). In Cox proportional hazard analyses, SGLT2i were associated with a 50-70% reduction in all-cause mortality and disease progression. SGLT2i were not associated with an increased risk of serious adverse events. CONCLUSION: SGLT2i were associated with a higher rate of survival in T2DM patients with colorectal cancer.


Asunto(s)
Neoplasias Colorrectales , Diabetes Mellitus Tipo 2 , Inhibidores del Cotransportador de Sodio-Glucosa 2 , Humanos , Inhibidores del Cotransportador de Sodio-Glucosa 2/uso terapéutico , Inhibidores del Cotransportador de Sodio-Glucosa 2/efectos adversos , Neoplasias Colorrectales/mortalidad , Neoplasias Colorrectales/tratamiento farmacológico , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/complicaciones , Masculino , Femenino , Estudios Retrospectivos , Persona de Mediana Edad , Anciano , Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/mortalidad , Resultado del Tratamiento , Tasa de Supervivencia , Estudios de Cohortes
4.
J Thromb Thrombolysis ; 57(5): 784-787, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38671166

RESUMEN

Patients with COVID-19 develop an increased risk of thromboembolism. Thromboprophylaxis is recommended for hospitalized COVID-19 patients, but the role of thromboprophylaxis in outpatients with COVID-19 is less well defined. We conducted a systematic review and meta-analysis to evaluate the safety and efficacy of thromboprophylaxis among outpatients with COVID-19. We searched PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, and Scopus from inception to August 2023. The outcomes of interest were venous thromboembolic events including deep venous thrombosis and pulmonary embolism, all-cause mortality, cardiovascular events, hospitalization, major bleeding events, and non-major bleeding events. We included 6 trials comprising 3352 patients. Patients who received thromboprophylaxis had an approximately 70% reduction in venous thromboembolism (RR, 0.28 [95% CI, 0.08 to 0.93]) compared to patients who did not receive thromboprophylaxis. The risk of mortality (RR, 0.79 [95% CI, 0.35 to 1.77]), cardiovascular events (RR, 0.91 [95% CI, 0.30 to 2.73]), and hospitalization (RR, 1.09 [95% CI, 0.81 to 1.47]) were similar between the two groups. Patients who received thromboprophylaxis had a higher risk of non-major bleeding (RR, 3.48 [95% CI, 1.72 to 7.05) compared to patients who did not receive thromboprophylaxis. Thromboprophylaxis reduced the risk of venous thromboembolism but not mortality, cardiovascular events, or hospitalization among outpatients with COVID-19.


Asunto(s)
COVID-19 , Tromboembolia Venosa , Humanos , COVID-19/complicaciones , COVID-19/mortalidad , Tromboembolia Venosa/prevención & control , Tromboembolia Venosa/etiología , Hemorragia/inducido químicamente , Pacientes Ambulatorios , Hospitalización , Anticoagulantes/uso terapéutico , Anticoagulantes/efectos adversos , SARS-CoV-2 , Embolia Pulmonar/prevención & control , Embolia Pulmonar/etiología , Atención Ambulatoria
5.
Cancer Immunol Immunother ; 72(6): 1951-1956, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36651967

RESUMEN

BACKGROUND: Immune checkpoint inhibitors have transformed the treatment landscape of cancer treatment, but only a fraction of patients responds to treatment, leading to an increasing effort to repurpose clinically approved medications to augment ICI therapy. Metformin has been associated with improved survival outcomes in patients undergoing conventional chemotherapy. However, whether metformin provides survival benefits in patients receiving immune checkpoint inhibitors (ICIs) is unknown. METHODS: We performed a retrospective cohort study at two tertiary referral centers in Taiwan. All adult diabetes mellitus patients who were treated with ICIs between January 2015 and December 2021 were included. The primary and secondary outcomes were overall survival (OS) and progression-free survival (PFS), respectively. RESULTS: In total, 878 patients were enrolled in our study, of which 86 patients used metformin and 78 patients used non-metformin diabetes medications. Compared with non-users, metformin users had a longer median OS (15.4 [IQR 5.6-not reached] vs. 6.1 [IQR, 0.8-21.0] months, P = 0.003) and PFS (5.1 [IQR 2.0-14.3] vs. 1.9 [IQR 0.7-8.6] months, P = 0.041). In a univariate Cox proportional hazard analysis, the use of metformin was associated with a reduction in the risk of mortality (HR: 0.53 [95% confidence interval: 0.35-0.81], P = 0.004) and disease progression (HR: 0.69 [95% CI 0.49-0.99], P = 0.042). The use of metformin remained associated with a lower risk of mortality after adjusting for baseline variables such as age, cancer stage, and underlying comorbidities (OS, HR: 0.55 [95% CI 0.34-0.87], P = 0.011). Similarly, the use of metformin was associated with a lower risk of disease progression. Importantly, the use of metformin before ICI initiation was not associated with a reduction in mortality (HR: 0.61 [95% CI 0.27-1.42], P = 0.25) or disease progression (HR: 0.69 [95% CI 0.33-1.43], P = 0.32). CONCLUSION: The use of metformin is associated with survival benefits in patients undergoing immunotherapy. Prospective clinical trials are warranted to define the role of metformin in augmenting immunotherapy.


Asunto(s)
Metformina , Adulto , Humanos , Metformina/uso terapéutico , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Estudios Retrospectivos , Estudios Prospectivos , Progresión de la Enfermedad
6.
J Virol ; 96(7): e0010722, 2022 04 13.
Artículo en Inglés | MEDLINE | ID: mdl-35293767

RESUMEN

The propagation of the hepatitis C virus (HCV) is regulated in part by the phosphorylation of its nonstructural protein NS5A that undergoes sequential phosphorylation on several highly conserved serine residues and switches from a hypo- to a hyperphosphorylated state. Previous studies have shown that NS5A sequential phosphorylation requires NS3 encoded on the same NS3-NS4A-NS4B-NS5A polyprotein. Subtle mutations in NS3 without affecting its protease activity could affect NS5A phosphorylation. Given the ATPase domain in the NS3 COOH terminus, we tested whether NS3 participates in NS5A phosphorylation similarly to the nucleoside diphosphate kinase-like activity of the rotavirus NSP2 nucleoside triphosphatase (NTPase). Mutations in the NS3 ATP-binding motifs blunted NS5A hyperphosphorylation and phosphorylation at serines 225, 232, and 235, whereas a mutation in the RNA-binding domain did not. The phosphorylation events were not rescued with wild-type NS3 provided in trans. When provided with an NS3 ATPase-compatible ATP analog, N6-benzyl-ATP-γ-S, thiophosphorylated NS5A was detected in the cells expressing the wild-type NS3-NS5B polyprotein. The thiophosphorylation level was lower in the cells expressing NS3-NS5B with a mutation in the NS3 ATP-binding domain. In vitro assays with a synthetic peptide and purified wild-type NS3 followed by dot blotting and mass spectrometry found weak NS5A phosphorylation at serines 222 and 225 that was sensitive to an inhibitor of casein kinase Iα but not helicase. When casein kinase Iα was included in the assay, much stronger phosphorylation was observed at serines 225, 232, and 235. We concluded that NS5A sequential phosphorylation requires the ATP-binding domain of the NS3 helicase and that casein kinase Iα is a potent NS5A kinase. IMPORTANCE For more than 20 years, NS3 was known to participate in NS5A sequential phosphorylation. In the present study, we show for the first time that the ATP-binding domain of NS3 is involved in NS5A phosphorylation. In vitro assays showed that casein kinase Iα is a very potent kinase responsible for NS5A phosphorylation at serines 225, 232, and 235. Our data suggest that ATP binding by NS3 probably results in conformational changes that recruit casein kinase Iα to phosphorylate NS5A, initially at S225 and subsequently at S232 and S235. Our discovery reveals intricate requirements of the structural integrity of NS3 for NS5A hyperphosphorylation and HCV replication.


Asunto(s)
Hepacivirus , Hepatitis C , ARN Polimerasa Dependiente del ARN , Proteínas no Estructurales Virales , Adenosina Trifosfatasas/genética , Adenosina Trifosfatasas/metabolismo , Caseína Quinasa Ialfa/metabolismo , Hepacivirus/enzimología , Hepacivirus/genética , Hepatitis C/virología , Humanos , Fosforilación , Poliproteínas/metabolismo , Dominios Proteicos/genética , ARN Polimerasa Dependiente del ARN/metabolismo , Proteínas no Estructurales Virales/genética , Proteínas no Estructurales Virales/metabolismo
7.
Oncology ; 101(9): 537-541, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37245500

RESUMEN

BACKGROUND: Statins are associated with improved survival outcomes in patients receiving immune checkpoint inhibitors (ICIs), but the impact of lipophilic and hydrophilic statin properties on patient outcomes is unknown. OBJECTIVES: We aim to investigate if statins with lipophilic properties are associated with clinical outcomes in patients receiving ICIs. METHOD: We conducted a retrospective cohort study at two tertiary referral centers in Taiwan comprising patients receiving ICIs between January 2015 and December 2021. We compared the comparative effect of lipophilic and hydrophilic statins on patient outcomes. The primary outcome was overall survival (OS) and the secondary outcome was progression-free survival (PFS). RESULTS: Among 734 patients receiving ICIs, there were 51 lipophilic statin users, 25 hydrophilic statin users, and 658 nonusers. Lipophilic statin users had a longer median OS (38.0 [IQR, 16.7-not reached] vs. 15.2 [IQR, 8.2-not reached] months vs. 18.9 [IQR, 5.4 51.6] months) and PFS (13.0 [IQR, 4.7-41.5] vs. 8.2 [IQR, 2.2-14.7] months vs. 5.6 [2.3-18.7] months) than hydrophilic statin users and non-statin users. In Cox proportional hazard analyses, the use of lipophilic statins was associated with a 40-50% lower risk of mortality and disease progression compared with hydrophilic statin or non-statin users. CONCLUSIONS: The use of lipophilic statins seems to be associated with survival benefits in patients undergoing immunotherapy.


Asunto(s)
Inhibidores de Hidroximetilglutaril-CoA Reductasas , Inhibidores de Puntos de Control Inmunológico , Humanos , Estudios Retrospectivos , Inhibidores de Hidroximetilglutaril-CoA Reductasas/efectos adversos , Progresión de la Enfermedad
8.
Ann Intern Med ; 175(1): 101-113, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34807719

RESUMEN

BACKGROUND: The 2020 European Society of Cardiology (ESC) guidelines recommend using the 0/1-hour and 0/2-hour algorithms over the 0/3-hour algorithm as the first and second choices of high-sensitivity cardiac troponin (hs-cTn)-based strategies for triage of patients with suspected acute myocardial infarction (AMI). PURPOSE: To evaluate the diagnostic accuracies of the ESC 0/1-hour, 0/2-hour, and 0/3-hour algorithms. DATA SOURCES: PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, and Scopus from 1 January 2011 to 31 December 2020. (PROSPERO: CRD42020216479). STUDY SELECTION: Prospective studies that evaluated the ESC 0/1-hour, 0/2-hour, or 0/3-hour algorithms in adult patients presenting with suspected AMI. DATA EXTRACTION: The primary outcome was index AMI. Twenty unique cohorts were identified. Primary data were obtained from investigators of 16 cohorts and aggregate data were extracted from 4 cohorts. Two independent authors assessed each study for methodological quality. DATA SYNTHESIS: A total of 32 studies (20 cohorts) with 30 066 patients were analyzed. The 0/1-hour algorithm had a pooled sensitivity of 99.1% (95% CI, 98.5% to 99.5%) and negative predictive value (NPV) of 99.8% (CI, 99.6% to 99.9%) for ruling out AMI. The 0/2-hour algorithm had a pooled sensitivity of 98.6% (CI, 97.2% to 99.3%) and NPV of 99.6% (CI, 99.4% to 99.8%). The 0/3-hour algorithm had a pooled sensitivity of 93.7% (CI, 87.4% to 97.0%) and NPV of 98.7% (CI, 97.7% to 99.3%). Sensitivity of the 0/3-hour algorithm was attenuated in studies that did not use clinical criteria (GRACE score <140 and pain-free) compared with studies that used clinical criteria (90.2% [CI, 82.9 to 94.6] vs. 98.4% [CI, 88.6 to 99.8]). All 3 algorithms had similar specificities and positive predictive values for ruling in AMI, but heterogeneity across studies was substantial. Diagnostic performance was similar across the hs-cTnT (Elecsys; Roche), hs-cTnI (Architect; Abbott), and hs-cTnI (Centaur/Atellica; Siemens) assays. LIMITATION: Diagnostic accuracy, inclusion and exclusion criteria, and cardiac troponin sampling time varied among studies. CONCLUSION: The ESC 0/1-hour and 0/2-hour algorithms have higher sensitivities and NPVs than the 0/3-hour algorithm for index AMI. PRIMARY FUNDING SOURCE: National Taiwan University Hospital.


Asunto(s)
Algoritmos , Biomarcadores/sangre , Infarto del Miocardio/diagnóstico , Guías de Práctica Clínica como Asunto , Triaje/métodos , Troponina/sangre , Diagnóstico Diferencial , Europa (Continente) , Humanos , Valor Predictivo de las Pruebas , Reproducibilidad de los Resultados , Factores de Riesgo , Sociedades Médicas , Factores de Tiempo
9.
Jpn J Clin Oncol ; 52(12): 1389-1398, 2022 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-36208180

RESUMEN

OBJECTIVES: Immune checkpoint inhibitors are associated with adverse cardiovascular events. However, there are no data characterizing cardiovascular events among Asians on immune checkpoint inhibitors. We aim to determine the incidence and risk of cardiac events associated with immune checkpoint inhibitors in an Asian population. METHODS: We performed a retrospective, propensity score-matched cohort study at two tertiary referral centers in Taiwan. Immune checkpoint inhibitor users were matched with non-immune checkpoint inhibitor users based on predetermined clinical variables. The primary outcome was major adverse cardiovascular events, defined as a composite of myocardial infarction, ischemic stroke, acute peripheral occlusive disease, pulmonary embolism, deep venous thrombosis, heart failure, pericardial disease, myocarditis, cardiac arrhythmias and conduction block. RESULTS: Between January 2010 and November 2021, 868 immune checkpoint inhibitor users were matched 1:1 with non-immune checkpoint inhibitor users. Among immune checkpoint inhibitor users, 67 (7.7%) patients developed major adverse cardiovascular events. During a median follow-up period of 188 days, the incidence rate of major adverse cardiovascular events for immune checkpoint inhibitor and non-immune checkpoint inhibitor users was 94.8 and 46.2 per 1000 patient-years, respectively, resulting in an incidence rate ratio of 2.1 [95% confidence interval: 1.5-2.9]. In multivariate Cox proportional hazard models, immune checkpoint inhibitor users had a 60% increased risk for major adverse cardiovascular events [hazard ratio, 1.6 (95% confidence interval: 1.1-2.3)]. Immune checkpoint inhibitors use was independently associated with increased risk of ischemic stroke [hazard ratio, 3.0 (95% confidence interval: 1.0-9.0)] and pulmonary embolism [hazard ratio, 5.5 (95% confidence interval: 1.4-21.3)]. In multivariate logistic regression analysis, age > 65, metastatic disease, hypertension and baseline platelet-to-lymphocyte ratio < 180 were risk factors for major adverse cardiovascular events. CONCLUSIONS: Among Asians, immune checkpoint inhibitors were associated with an increased risk of major adverse cardiovascular events, particularly ischemic stroke and pulmonary embolism.


Asunto(s)
Enfermedades Cardiovasculares , Diabetes Mellitus Tipo 2 , Accidente Cerebrovascular Isquémico , Infarto del Miocardio , Embolia Pulmonar , Humanos , Enfermedades Cardiovasculares/inducido químicamente , Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/complicaciones , Estudios de Cohortes , Diabetes Mellitus Tipo 2/complicaciones , Inhibidores de Puntos de Control Inmunológico/efectos adversos , Incidencia , Infarto del Miocardio/complicaciones , Infarto del Miocardio/epidemiología , Embolia Pulmonar/complicaciones , Estudios Retrospectivos , Pueblo Asiatico
10.
Surg Today ; 52(6): 896-903, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35034198

RESUMEN

BACKGROUND AND OBJECTIVES: Multiple-port robotic pancreaticoduodenectomy (RPD) has been increasingly used as an alternative to open pancreaticoduodenectomy (OPD) in pancreatic cancer. However, the comparative safety and efficacy of reduced-port RPD versus OPD are unknown. METHODS: This was a prospective cohort study comprising adult patients who underwent reduced-port RPD (single-port or single-site plus one port) or OPD for malignant tumors of the pancreas and periampullary region from July 2015 to October 2020 at a single center. We collected data on the patient demographics, perioperative results, oncologic outcomes, and one-year survival. RESULTS: Forty-five patients underwent reduced-port RPD, and 13 underwent OPD. There were no significant differences in the age, sex, body mass index, ASA score, tumor location, or occurrences of postoperative complications between the two groups. Compared with OPD, reduced-port RPD was associated with less blood loss (300 ml [95% confidence interval {CI} 155-700] vs. 650 ml [95% CI 300-850], p value = 0.11) but a longer operative time (325 min [95% CI 290-370] vs. 215 min [95% CI 180-270], p value < 0.001). Compared with patients who underwent OPD, patients who underwent reduced-port RPD had a higher 1-year survival rate (68% [95% CI 49-81] vs. 22% [95% CI 3-51], log-rank, p value = 0.007). CONCLUSIONS: Reduced-port RPD can be safely performed in experienced surgeons and is associated with better perioperative and oncologic outcomes than OPD.


Asunto(s)
Laparoscopía , Neoplasias Pancreáticas , Procedimientos Quirúrgicos Robotizados , Cirujanos , Adulto , Humanos , Tiempo de Internación , Neoplasias Pancreáticas/cirugía , Pancreaticoduodenectomía/métodos , Complicaciones Posoperatorias/etiología , Estudios Prospectivos , Estudios Retrospectivos , Procedimientos Quirúrgicos Robotizados/métodos
11.
J Virol ; 94(19)2020 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-32699091

RESUMEN

Replication of the genotype 2 hepatitis C virus (HCV) requires hyperphosphorylation of the nonstructural protein NS5A. It has been known that NS5A hyperphosphorylation results from the phosphorylation of a cluster of highly conserved serine residues (S2201, S2208, S2211, and S2214) in a sequential manner. It has also been known that NS5A hyperphosphorylation requires an NS3 protease encoded on one single NS3-5A polyprotein. It was unknown whether NS3 protease participates in this sequential phosphorylation process. Using an inventory of antibodies specific to S2201, S2208, S2211, and S2214 phosphorylation, we found that protease-dead S1169A mutation abrogated NS5A hyperphosphorylation and phosphorylation at all serine residues measured, consistent with the role of NS3 in NS5A sequential phosphorylation. These effects were not rescued by a wild-type NS3 protease provided in trans by another molecule. Mutations (T1661R, T1661Y, or T1661D) that prohibited proper cleavage at the NS3-4A junction also abolished NS5A hyperphosphorylation and phosphorylation at all serine residues, whereas mutations at the other cleavage sites, NS4A-4B (C1715S) or NS4B-5A (C1976F), did not. In fact, any combinatory mutations that prohibited NS3-4A cleavage (T1661Y/C1715S or T1661Y/C1976F) abrogated NS5A hyperphosphorylation and phosphorylation at all serine residues. In the C1715S/C1976F double mutant, which resulted in an NS4A-NS4B-NS5A fusion polyprotein, a hyperphosphorylated band was observed and was phosphorylated at all serine residues. We conclude that NS3-mediated autocleavage at the NS3-4A junction is critical to NS5A hyperphosphorylation at S2201, S2208, S2211, and S2214 and that NS5A hyperphosphorylation could occur in an NS4A-NS4B-NS5A polyprotein.IMPORTANCE For ca. 20 years, the HCV protease NS3 has been implicated in NS5A hyperphosphorylation. We now show that it is the NS3-mediated cis cleavage at the NS3-4A junction that permits NS5A phosphorylation at serines 2201, 2208, 2211, and 2214, leading to hyperphosphorylation, which is a necessary condition for genotype 2 HCV replication. We further show that NS5A may already be phosphorylated at these serine residues right after NS3-4A cleavage and before NS5A is released from the NS4A-5A polyprotein. Our data suggest that the dual-functional NS3, a protease and an ATP-binding RNA helicase, could have a direct or indirect role in NS5A hyperphosphorylation.


Asunto(s)
Hepacivirus/metabolismo , Proteínas no Estructurales Virales/metabolismo , Línea Celular , Células HEK293 , Humanos , Mutación , Fosforilación , Poliproteínas/metabolismo , ARN Helicasas
12.
J Virol ; 93(23)2019 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-31511391

RESUMEN

The nonstructural protein NS5A of hepatitis C virus (HCV) is a phosphorylated protein that is indispensable for viral replication and assembly. We previously showed that NS5A undergoes sequential serine S232/S235/S238 phosphorylation resulting in NS5A transition from a hypo- to a hyperphosphorylated state. Here, we studied functions of S229 with a newly generated antibody specific to S229 phosphorylation. In contrast to S232, S235, or S238 phosphorylation detected only in the hyperphosphorylated NS5A, S229 phosphorylation was found in both hypo- and hyperphosphorylated NS5A, suggesting that S229 phosphorylation initiates NS5A sequential phosphorylation. Immunoblotting showed an inverse relationship between S229 phosphorylation and S235 phosphorylation. When S235 was phosphorylated as in the wild-type NS5A, the S229 phosphorylation level was low; when S235 could not be phosphorylated as in the S235A mutant NS5A, the S229 phosphorylation level was high. These results suggest an intrinsic feedback regulation between S229 phosphorylation and S235 phosphorylation. It has been known that NS5A distributes in large static and small dynamic intracellular structures and that both structures are required for the HCV life cycle. We found that S229A or S229D mutation was lethal to the virus and that both increased NS5A in large intracellular structures. Similarly, the lethal S235A mutation also increased NS5A in large structures. Likewise, the replication-compromised S235D mutation also increased NS5A in large structures, albeit to a lesser extent. Our data suggest that S229 probably cycles through phosphorylation and dephosphorylation to maintain a delicate balance of NS5A between hypo- and hyperphosphorylated states and the intracellular distribution necessary for the HCV life cycle.IMPORTANCE This study joins our previous efforts to elucidate how NS5A transits between hypo- and hyperphosphorylated states via phosphorylation on a series of highly conserved serine residues. Of the serine residues, serine 229 is the most interesting since phosphorylation-mimicking and phosphorylation-ablating mutations at this serine residue are both lethal. With a new high-quality antibody specific to serine 229 phosphorylation, we concluded that serine 229 must remain wild type so that it can dynamically cycle through phosphorylation and dephosphorylation that govern NS5A between hypo- and hyperphosphorylated states. Both are required for the HCV life cycle. When phosphorylated, serine 229 signals phosphorylation on serine 232 and 235 in a sequential manner, leading NS5A to the hyperphosphorylated state. As serine 235 phosphorylation is reached, serine 229 is dephosphorylated, stopping signal for hyperphosphorylation. This balances NS5A between two phosphorylation states and in intracellular structures that warrant a productive HCV life cycle.


Asunto(s)
Hepacivirus/metabolismo , Serina/metabolismo , Proteínas no Estructurales Virales/genética , Proteínas no Estructurales Virales/metabolismo , Secuencia de Aminoácidos , Animales , Línea Celular Tumoral , Células HEK293 , Hepatitis C/virología , Humanos , Fosforilación , Proteínas Quinasas/metabolismo , Proteómica , Renilla , Proteínas no Estructurales Virales/química , Replicación Viral/fisiología
17.
Emerg Med J ; 38(12): 900-940, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34819331
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