Life Sciences Commons^™

Alcohol And Hcv: Implications For Liver Cancer, Gyongyi Szabo, Banishree Saha, Terence Bukong

Gyongyi Szabo

Liver cancers are one of the deadliest known malignancies which are increasingly becoming a major public health problem in both developed and developing countries. Overwhelming evidence suggests a strong role of infection with hepatitis B and C virus (HBV and HCV), alcohol abuse, as well as metabolic diseases such as obesity and diabetes either individually or synergistically to cause or exacerbate the development of liver cancers. Although numerous etiologic mechanisms for liver cancer development have been advanced and well characterized, the lack of definite curative treatments means that gaps in knowledge still exist in identifying key molecular mechanisms and pathways …

The Genetics Of Hepatitis C Virus Underlie Its Ability To Escape Humoral Immunity, Jay Kolls, Gyongyi Szabo

Gyongyi Szabo

Hepatitis C virus (HCV) is a leading cause of chronic liver disease, and efforts to develop therapeutic vaccine strategies have been limited by immune escape due to HCV variants that are resistant to current vaccines or HCV variants that rapidly acquire new resistance-conferring mutations. Recently, the crystal structure of the viral envelope protein E2 region was resolved as well as how E2 docks to the host CD81 protein; therefore, antibodies that block this interaction should prevent viral entry into host cells. In this issue of the JCI, Bailey and colleagues show that immune escape of HCV can occur by naturally …

Prepubertal Organochlorine Pesticide Concentrations And Age Of Pubertal Onset Among Russian Boys, Thuy Lam, Paige Williams, Mary Lee, Susan Korrick, Linda Birnbaum, Jane Burns, Oleg Sergeyev, Boris Revich, Larisa Altshul, Donald Patterson, Wayman Turner, Russ Hauser

Mary M. Lee

BACKGROUND: In animal studies, organochlorine pesticide (OCP) exposure alters pubertal development; however, epidemiological data are limited and inconsistent. OBJECTIVE: To evaluate the associations of serum OCP concentrations [hexachlorobenzene (HCB), beta-hexachlorocyclohexane (beta-HCH), and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE)] with male pubertal onset. METHODS: In Chapaevsk, Russia, a town environmentally contaminated with OCPs, 350 8-9 year old boys with measured OCPs were enrolled during 2003-2005 and were followed annually for eight years. We evaluated three measures of pubertal onset: testicular volume (TV) > 3 mL in either testis, or stage 2 or greater for genitalia (G2+), or pubic hair (P2+). We used multivariable interval-censored models to …

Association Between Chlorinated Pesticides In The Serum Of Prepubertal Russian Boys And Longitudinal Biomarkers Of Metabolic Function, Jane Burns, Paige Williams, Susan Korrick, Russ Hauser, Oleg Sergeyev, Boris Revich, Thuy Lam, Mary Lee

Mary M. Lee

Organochlorine pesticides (OCPs) have been linked to adult metabolic disorders; however, few studies have examined these associations in childhood. We prospectively evaluated the associations of baseline serum OCPs (hexachlorobenzene, beta-hexachlorocyclohexane, and p,p'-dichlorodiphenyldichloroethylene) in Russian boys with subsequent repeated measurements of serum glucose, insulin, lipids, leptin, and calculated homeostatic model assessment of insulin resistance (IR). During 2003-2005, we enrolled 499 boys aged 8-9 years in a prospective cohort; 318 had baseline serum OCPs and serum biomarkers measured at ages 10-13 years. Multivariable generalized estimating equation and mediation regression models were used to examine associations and direct and indirect (via body mass …

Interview With Celia Schiffer, Celia Schiffer

Celia A. Schiffer

Celia Schiffer, a Professor in Biochemistry and Molecular Pharmacology; a former Director of UMass Center for AIDS Research; and a Founder and Co-Director for the Institute for Drug Resistance (University of Massachusetts Medical School, MA, USA). Schiffer has an undergraduate degree in physics from the University of Chicago, with a PhD in biophysics from University of California, San Francisco (CA, USA). She was a postdoctoral associate first at the ETH in Zurich and then at Genentech in San Francisco. Schiffer has published more than 100 peer reviewed journal articles. Her laboratory primarily uses structural biology, biophysical and chemistry techniques to …

Xk Aprosencephaly And Anencephaly In Sibs, Phillip Townes, Karen Reuter, E. Rosquete, B. Magee

B. Dale Magee

Recent studies have suggested a causal and pathogenetic relationship between holoprosencephaly and anencephaly. In support of the proposed relationship we report a sibship that includes anencephalic male twins and a female infant with a severe form of alobar holoprosencephaly, radial aplasia, and oligodactyly. The upper limb and brain malformations are considered to represent aprosencephaly syndrome. The coexistence of anencephaly and aprosencephaly within a sibship suggests that XK aprosencephaly syndrome may be an autosomal recessive disorder.

Another Armed Cd4(+) T Cell Ready To Battle Hepatocellular Carcinoma, Roniel Cabrera, Gyongyi Szabo

Gyongyi Szabo

No abstract provided.

Human Ezrin-Moesin-Radixin Proteins Modulate Hepatitis C Virus Infection, Terence Bukong, Karen Kodys, Gyongyi Szabo

Gyongyi Szabo

Host cytoskeletal proteins of the ezrin-moesin-radixin (EMR) family have been shown to modulate single-stranded RNA virus infection through regulating stable microtubule formation. Antibody engagement of CD81, a key receptor for hepatitis C virus (HCV) entry, induces ezrin phosphorylation. Here we tested the role of EMR proteins in regulating HCV infection and explored potential therapeutic targets. We show that HCV E2 protein induces rapid ezrin phosphorylation and its cellular redistribution with F-actin by way of spleen tyrosine kinase (SYK). Therapeutically blocking the functional roles of SYK or F-actin reorganization significantly reduced Huh7.5 cell susceptibility to HCV J6/JFH-1 infection. Using gene regulation, …

Differences In Innate Immune Signaling Between Alcoholic And Non-Alcoholic Steatohepatitis, Jan Petrasek, Timea Csak, Michal Ganz, Gyongyi Szabo

Gyongyi Szabo

The similar histopathological characteristics of alcoholic steatohepatitis (ASH) and non-alcoholic steatohepatitis (NASH), and the crucial role of the innate immune response in both conditions may lead to the assumption that ASH and NASH represent the same pathophysiological entities caused by different risk factors. In this review paper, we elaborate on the pathophysiological differences between these two entities and highlight the disease-specific involvement of signaling molecules downstream of the Toll-like receptor 4, and the differential mechanism by which the inflammasome contributes to ASH versus NASH. Our findings emphasize that ASH and NASH have disease-specific mechanisms and therefore represent distinct biological entities. …

Human Type 2 Myeloid Dendritic Cells Produce Interferon-Lambda And Amplify Interferon-Alpha In Response To Hepatitis C Virus Infection, Shuye Zhang, Karen Kodys, Kui Li, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND and AIMS: The type III interferons (IFN-lambdas: interleukin [IL]-28a, IL-28b, and IL-29) have important roles in hepatitis C virus (HCV) infection, but little is understood about what cells produce these cytokines or how production is activated. We investigated whether human immune cells recognize HCV-infected cells and respond by producing IFN-lambda. METHODS: We cultured healthy human peripheral blood mononuclear cells (PBMCs) with different populations of immune cells and Japanese fulminant hepatitis-1 (JFH-1) HCV-infected Huh7.5 (cell culture-derived HCV particles [HCVcc]/Huh7.5) cells. RESULTS: Human PBMCs recognized HCVcc/Huh7.5 cells and responded by producing IFN-alpha, IFN-gamma, and IFN-lambda. A rare subset of myeloid dendritic …

Toll-Like Receptors In Liver Disease, Jan Petrasek, Timea Csak, Gyongyi Szabo

Gyongyi Szabo

Activation of inflammatory signaling pathways is of central importance in the pathogenesis of alcoholic liver disease (ALD) and nonalcoholic steatohepatitis (NASH). Recent studies demonstrated that Toll-like receptors, the sensors of microbial and endogenous danger signals, are expressed and activated in innate immune cells as well as in parenchymal cells in the liver and thereby contribute to ALD and NASH. In this review, we emphasize the importance of gut-derived endotoxin and its recognition by TLR4 in the liver. The significance of TLR-induced intracellular signaling pathways and cytokine production as well as the contribution of individual cell types to the inflammation is …

Structural And Thermodynamic Basis Of Amprenavir/Darunavir And Atazanavir Resistance In Hiv-1 Protease With Mutations At Residue 50, Seema Mittal, Rajintha Bandaranayake, Nancy King, Moses Prabu-Jeyabalan, Madhavi Nalam, Ellen Nalivaika, Nese Yilmaz, Celia Schiffer

Celia A. Schiffer

Drug resistance occurs through a series of subtle changes that maintain substrate recognition but no longer permit inhibitor binding. In HIV-1 protease, mutations at I50 are associated with such subtle changes that confer differential resistance to specific inhibitors. Residue I50 is located at the protease flap tips, closing the active site upon ligand binding. Under selective drug pressure, I50V/L substitutions emerge in patients, compromising drug susceptibility and leading to treatment failure. The I50V substitution is often associated with amprenavir (APV) and darunavir (DRV) resistance, while the I50L substitution is observed in patients failing atazanavir (ATV) therapy. To explain how APV, …

Dendritic Cells In Hepatitis C Infection: Can They (Help) Win The Battle, Angela Dolganiuc, Gyongyi Szabo

Gyongyi Szabo

Infection with hepatitis C virus (HCV) is a public health problem; it establishes a chronic course in ~85% of infected patients and increases their risk for developing liver cirrhosis, hepatocellular carcinoma, and significant extrahepatic manifestations. The mechanisms of HCV persistence remain elusive and are largely related to inefficient clearance of the virus by the host immune system. Dendritic cells (DCs) are the most efficient inducers of immune responses; they are capable of triggering productive immunity and maintaining the state of tolerance to self- and non-self antigens. During the past decade, multiple research groups have focused on DCs, in hopes of …

Hypoxia And Hypoxia Inducible Factors: Diverse Roles In Liver Diseases, Bharath Nath, Gyongyi Szabo

Gyongyi Szabo

Hypoxia has been shown to have a role in the pathogenesis of several forms of liver disease. The hypoxia inducible factors (HIFs) are a family of evolutionarily conserved transcriptional regulators that affect a homeostatic response to low oxygen tension and have been identified as key mediators of angiogenesis, inflammation, and metabolism. In this review we summarize the evidence for a role of HIFs across a range of hepatic pathophysiology. We describe regulation of the HIFs and review investigations that demonstrate a role for HIFs in the development of liver fibrosis, activation of innate immune pathways, hepatocellular carcinoma, as well as …

Mitochondrial Antiviral Signaling Protein Defect Links Impaired Antiviral Response And Liver Injury In Steatohepatitis In Mice, Timea Csak, Angela Dolganiuc, Karen Kodys, Bharath Nath, Jan Petrasek, Shashi Bala, Dora Lippai, Gyongyi Szabo

Gyongyi Szabo

Mitochondrial dysfunction is a pathogenic feature of nonalcoholic steatohepatitis (NASH). NASH complicates hepatotropic viral disease. The mitochondrial antiviral signaling protein (MAVS) is the adapter of helicase receptors involved in sensing double-stranded RNA (dsRNA). We hypothesized that impaired MAVS function may contribute to insufficient antiviral response and liver damage in steatohepatitis. We identified reduced MAVS protein levels and increased MAVS association with the proteasome subunit alpha type 7 (PSMA7) in livers from mice given a methionine-choline-deficient (MCD) diet. Decreased association of MAVS with mitochondria and increased cytosolic cytochrome c indicated mitochondrial damage in steatohepatitis. In vivo administration of the synthetic dsRNA …

An Essential Role For Monocyte Chemoattractant Protein-1 In Alcoholic Liver Injury: Regulation Of Proinflammatory Cytokines And Hepatic Steatosis In Mice, Pranoti Mandrekar, Aditya Ambade, Arlene Lim, Gyongyi Szabo, Donna Catalano

Gyongyi Szabo

The importance of chemokines in alcoholic liver injury has been implicated. The role of the chemokine, monocyte chemoattractant protein-1 (MCP-1), elevated in patients with alcoholic liver disease is not yet understood. Here, we evaluated the pathophysiological significance of MCP-1 and its receptor, chemokine (C-C motif) receptor 2 (CCR2), in alcoholic liver injury. The Leiber-DeCarli diet containing alcohol or isocaloric control diets were fed to wild-type (WT) and MCP-1-deficient knockout (KO) mice for 6 weeks. In vivo and in vitro assays were performed to study the role of MCP-1 in alcoholic liver injury. MCP-1 was increased in Kupffer cells (KCs) as …

Novel Developmental Biology-Based Protocol Of Embryonic Stem Cell Differentiation To Morphologically Sound And Functional Yet Immature Hepatocytes, Terence Bukong, Tracie Lo, Gyongyi Szabo, Angela Dolganiuc

Gyongyi Szabo

BACKGROUND/AIMS: Liver diseases are common in the United States and often require liver transplantation; however, donated organs are limited and thus alternative sources for liver cells are in high demand. Embryonic stem cells (ESC) can provide a continuous and readily available source of liver cells. ESC differentiation to liver cells is yet to be fully understood and comprehensive differentiation protocols are yet to be defined. Here, we aimed to achieve human (h)ESC differentiation into mature hepatocytes using defined recombinant differentiation factors and metabolites. METHODS: Embryonic stem cell H1 line was sub-cultured on feeder layer. We induced hESCs into endodermal differentiation …

Immune Responses In Cystic Fibrosis: Are They Intrinsically Defective?, Dmitry Ratner, Christian Mueller

Christian Mueller

Cystic fibrosis (CF), the most common lethal single-gene disorder affecting Northern Europeans and North Americans, is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Cftr is a chloride channel and a regulator of other ion channels, and many aspects of the CF phenotype are directly related to ion channel abnormalities attributable to CFTR mutation. Lung disease is the most common limitation to the quantity and quality of life for patients with CF. One aspect that continues to be enigmatic is the observed alterations in innate and adaptive immune responses to certain pathogens. Altered responses to Pseudomonas …

Body Mass Index, Treatment Practices, And Mortality In Patients With Acute Heart Failure, Timothy Fitzgibbons, Olga Hardy, Darleen Lessard, Joel Gore, Jorge Yarzebski, Robert Goldberg

Jorge L. Yarzebski

OBJECTIVES: Obesity is associated with an increased risk of heart failure (HF). Among patients presenting with acute HF, however, differences in clinical characteristics, treatment regimens, and short-term prognosis of varying weights are largely unknown, particularly from a broader population-based perspective. METHODS: A total of 3722 patients admitted with acute HF to 11 greater Worcester (Massachusetts, USA) hospitals during 1995 and 2000 were categorized as being lean (n = 216), normal weight (n = 1465), overweight (n = 1007), or obese (n = 1034) at the time of hospitalization. RESULTS: Obese patients with decompensated HF were significantly younger (mean age = …

Multidecade-Long Trends (1986-2005) In The Utilization Of Coronary Reperfusion And Revascularization Treatment Strategies In Patients Hospitalized With Acute Myocardial Infarction: A Community-Wide Perspective, Jared Wasser, Robert Goldberg, Frederick Spencer, Jorge Yarzebski, Joel Gore

Jorge L. Yarzebski

OBJECTIVES: The objectives of our community-wide investigation were to describe multidecade-long trends (1986-2005) in the utilization of thrombolytic therapy, percutaneous coronary interventions, and coronary artery bypass graft surgery in patients hospitalized with acute myocardial infarction (AMI). METHODS: The study sample consisted of 9422 greater Worcester (MA) residents hospitalized with confirmed AMI at all metropolitan Worcester medical centers in 11 annual periods between 1986 and 2005. RESULTS: Increases in the utilization of percutaneous coronary interventions were observed between 1986 (2.0%) and 2005 (50.7%) with the most rapid increases beginning in the late 1990s. Utilization of coronary artery bypass graft surgery during …

Long-Term Trends In The Use Of Coronary Reperfusion Strategies In Acute Myocardial Infarction: A Community-Wide Perspective, Robert Goldberg, Frederick Spencer, Joseph Okolo, Darleen Lessard, Jorge Yarzebski, Joel Gore

Jorge L. Yarzebski

BACKGROUND: The objectives of our study were to examine long-term (1986-2003) trends in the use of percutaneous coronary interventions (PCI) and thrombolytic therapy in the management of patients hospitalized with acute myocardial infarction (AMI) while our secondary study goal was to examine factors associated with use of these coronary reperfusion strategies. While there have been considerable changes in the management of patients hospitalized with AMI over time, limited contemporary data are available about changing trends in the use of different coronary reperfusion strategies, particularly from the more generalizable perspective of a population-based investigation. METHODS: The study sample consisted of 9,422 …

Use Of Do-Not-Resuscitate Orders In Patients With Kidney Disease Hospitalized With Acute Myocardial Infarction, Joline Chen, Jonathan Sosnov, Darleen Lessard, Jorge Yarzebski, Joel Gore, Robert Goldberg

Jorge L. Yarzebski

BACKGROUND: Patients with kidney disease are at increased risk for adverse health outcomes in comparison to patients without kidney disease. Therefore, patients with kidney disease may have greater use of do-not-resuscitate (DNR) orders than patients without kidney disease in the setting of an acute illness. We examined the association between advanced kidney disease and use of DNR orders in patients admitted with an acute myocardial infarction (AMI) to all greater Worcester, MA, hospitals as part of an epidemiological study.

METHODS: Use of DNR orders in 4,033 Worcester residents hospitalized with AMI at 11 greater Worcester medical centers during 1997, 1999, …

Treatment Practices And Outcomes Of Patients With Established Peripheral Arterial Disease Hospitalized With Acute Myocardial Infarction In A Community Setting, Frederick Spencer, Darleen Lessard, Chyke Doubeni, Jorge Yarzebski, Joel Gore, Robert Goldberg

Jorge L. Yarzebski

BACKGROUND: There are little contemporary data available describing the hospital and long-term outcomes of patients with peripheral arterial disease (PAD) who are hospitalized with acute myocardial infarction (AMI). The objectives of our population-based study were to examine the hospital and long-term outcomes, as well as the use of different treatment practices, among patients with established PAD who were hospitalized with AMI. METHODS: The study sample consisted of 4480 patients hospitalized with AMI at all Worcester, Mass, medical centers in 4 alternate years between 1997 and 2003. RESULTS: Among the metropolitan Worcester residents hospitalized with AMI, 13.5% had a history of …