Human type 2 myeloid dendritic cells produce interferon-lambda and amplify interferon-alpha in response to hepatitis C virus infection
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 cells (mDCs), which are blood DC antigen (BDCA)+ (also called mDC2 cells), were the major source of IL-28 and IL-29 production in response to HCVcc/Huh7.5 cells. Plasmacytoid DCs produced IFN-alpha, whereas natural killer and natural killer T cells were the main source of IFN-gamma production in co-culture experiments. Of the endosomal Toll-like receptors (TLRs)3, 7, 8, and 9, only TLR3 or double-stranded HCV RNA induced production of IL-28 and IL-29 by mDC2s; endosomal maturation was required. Production of IFN-alpha and IFN-lambda were linked-IFN-lambda increased production of IFN-alpha by plasmacytoid DCs and IFN-alpha significantly increased production of IFN-lambda.
CONCLUSIONS: mDC2s are a major source of IFN-lambda production by PBMCs in response to HCVcc/Huh7.5 cells. mDC2s are activated through the TLR3 pathway, indicating that human DCs efficiently can initiate an immune response against HCV infection. IFN-lambda therefore has an important role in HCV infection.
Binge consumption of alcohol is an alarming global health problem. Binge (acute) ethanol (EtOH) is implicated in the pathophysiology of alcoholic liver disease (ALD). New studies from experimental animals and from humans indicate that binge EtOH has profound effects on immunological, signaling, and epigenetic parameters of the liver. This is in addition to the known metabolic effects of acute EtOH. Binge EtOH alters the levels of several cellular components and dramatically amplifies liver injury in chronically EtOH exposed liver. These studies highlight the importance of molecular investigations into binge effects of EtOH for a better understanding of ALD and also to develop therapeutic strategies to control it. This review summarizes these recent developments.
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. Further studies are needed to dissect the emerging differences in pathogenesis of these two conditions. Publishing Asia Pty Ltd.
STING-IRF3 pathway links endoplasmic reticulum stress with hepatocyte apoptosis in early alcoholic liver disease
Emerging evidence suggests that innate immunity drives alcoholic liver disease (ALD) and that the interferon regulatory factor 3 (IRF3),a transcription factor regulating innate immune responses, is indispensable for the development of ALD. Here we report that IRF3 mediates ALD via linking endoplasmic reticulum (ER) stress with apoptotic signaling in hepatocytes. We found that ethanol induced ER stress and triggered the association of IRF3 with the ER adaptor, stimulator of interferon genes (STING), as well as subsequent phosphorylation of IRF3. Activated IRF3 associated with the proapoptotic molecule Bax [B-cell lymphoma 2 (Bcl2)-associated X protein] and contributed to hepatocyte apoptosis. Deficiency of STING prevented IRF3 phosphorylation by ethanol or ER stress, and absence of IRF3 prevented hepatocyte apoptosis. The pathogenic role of IRF3 in ALD was independent of inflammation or Type-I interferons. Thus, STING and IRF3 are key determinants of ALD, linking ER stress signaling with the mitochondrial pathway of hepatocyte apoptosis.
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, real-time quantitative polymerase chain reaction, western blot, and fluorescent microscopy analysis, we found that proteins of the EMR family differentially regulate HCV infection in the J6/JFH-1/Huh7.5 cell system. Moesin and radixin, but not ezrin, expression were significantly decreased in chronic HCV J6/JFH-1-infected Huh7.5 cells and HCV-infected patient liver biopsies compared to controls. The decreases in moesin and radixin in HCV J6/JFH-1-infected Huh7.5 cells were associated with a significant increase in stable microtubules. Ezrin knockdown inhibited immediate postentry events in HCV infection. Overexpression of moesin or radixin significantly reduced HCV protein expression. In contrast, transient knockdown of moesin or radixin augmented HCV infection. Making use of the Con1 HCV replicon system, we tested the effect of EMR proteins on HCV replication. We found that transient knockdown of moesin increased HCV RNA expression while overexpression of EMR showed no significant effect on HCV replication.
CONCLUSION: Our findings demonstrate the important role of EMR proteins during HCV infection at the postentry level and highlight possible novel targets for HCV treatment.
Immune and inflammatory pathways have a central role in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Both the innate and adaptive immune systems contribute to the development of NAFLD. Pathogen-associated molecular patterns and danger-associated molecular patterns are known to activate a variety of pattern-recognition receptors that result in inflammation. The key features of the immune system and inflammatory pathways in the development of NAFLD are discussed in this review.
Binge drinking, the most common form of alcohol consumption, is associated with increased mortality and morbidity; yet, its biological consequences are poorly defined. Previous studies demonstrated that chronic alcohol use results in increased gut permeability and increased serum endotoxin levels that contribute to many of the biological effects of chronic alcohol, including alcoholic liver disease. In this study, we evaluated the effects of acute binge drinking in healthy adults on serum endotoxin levels. We found that acute alcohol binge resulted in a rapid increase in serum endotoxin and 16S rDNA, a marker of bacterial translocation from the gut. Compared to men, women had higher blood alcohol and circulating endotoxin levels. In addition, alcohol binge caused a prolonged increase in acute phase protein levels in the systemic circulation. The biological significance of the in vivo endotoxin elevation was underscored by increased levels of inflammatory cytokines, TNFalpha and IL-6, and chemokine, MCP-1, measured in total blood after in vitro lipopolysaccharide stimulation. Our findings indicate that even a single alcohol binge results in increased serum endotoxin levels likely due to translocation of gut bacterial products and disturbs innate immune responses that can contribute to the deleterious effects of binge drinking.
Chronic excessive alcohol consumption results in inflammation in multiple organs, including the brain. While the contribution of neuroinflammation to alcohol-related cognitive dysfunction and behavioral alterations is established, the mechanisms by which alcohol triggers inflammation in the brain are only partially understood. There are acute and long-term alterations in brain function due to intercellular and intracellular changes of different cell types as a result of alcohol consumption. This review focuses on the alcohol-induced proinflammatory cellular and molecular changes in the central nervous system. Alcohol passes through the blood-brain barrier and alters neurotransmission. Alcohol use activates microglia and astrocyte, contributing to neurodegeneration and impaired regeneration. Alcohol-induced cell injury in the brain results in release of damage-associated molecular patterns, such as high mobility group box 1, that trigger inflammatory changes through activation of pattern recognition receptors. In addition, alcohol consumption increases intestinal permeability and results in increased levels of pathogen-associated molecular pattern such as endotoxin in the systemic circulation that triggers PRRs and inflammation. The Toll-like receptor-4 pathway that activates nuclear factor-kappaB and secretion of proinflammatory cytokines, tumor necrosis factor-alpha, interleukin-1-beta, and chemokines, including monocyte chemotactic protein-1, has been suggested to contribute to alcohol-induced neuroinflammation. Alcohol-induced IL-1beta secretion also requires Nod-like receptor-mediated inflammasome and caspase-1 activation, and, consistent with this, disruption of IL-1/IL-1-receptor signaling prevents alcohol-induced neuroinflammation. Delicate regulators of inflammatory gene expressions are micro-RNAs (miRs) that have recently been identified in alcohol-related neuroinflammation. Alcohol induces miR155, a regulator of inflammation in the brain, and deficiency in miR-155 in mice was protective from neuroinflammatory changes. These observations suggest that manipulation of miR pathways and cytokine induction may reduce alcohol-induced proinflammatory processes.
Both bone marrow-derived and non-bone marrow-derived cells contribute to AIM2 and NLRP3 inflammasome activation in a MyD88-dependent manner in dietary steatohepatitis
BACKGROUND and AIMS: Inflammation promotes the progression of non-alcoholic steatohepatitis (NASH). Toll-like receptor 4 (TLR4) and TLR9 activation through myeloid differentiation primary response gene 88 (MyD88) and production of mature interleukin-1beta (IL-1beta) via inflammasome activation contribute to steatohepatitis. Here, we investigated the inter-relationship between TLR signalling and inflammasome activation in dietary steatohepatitis.
METHODS: Wild type (WT), TLR4- and MyD88-deficient (KO) mice received methionine-choline-deficient (MCD) or -supplemented (MCS) diets for 5 weeks and a subset was challenged with TLR9 ligand CpG-DNA.
RESULTS: TLR4, TLR9, AIM2 (absent in melanoma 2) and NLRP3 (NLR family pyrin domain containing 3) inflammasome mRNA, and mature IL-1beta protein levels were increased in MCD diet-induced steatohepatitis compared to MCS controls. TLR9 stimulation resulted in greater up-regulation of the DNA-sensing AIM2 expression and IL-1beta production in livers of MCD compared to MCS diet-fed mice. High mobility group box 1 (HMGB1), a TLR9-activating danger molecule and phospho-HMGB1 protein levels were also increased in livers of MCD diet-fed mice. MyD88- but not TLR4-deficiency prevented up-regulation of AIM2, NLRP3 mRNA and IL-1beta protein production in dietary steatohepatitis. Selective MyD88 deficiency either in bone marrow (BM)-derived or non-BM-derived cells attenuated hepatic up-regulation of inflammasome mRNA, caspase-1 activation and IL-1beta protein production, but only BM-derived cell-specific MyD88-deficiency attenuated liver injury.
CONCLUSIONS: Our data demonstrate that both bone marrow-derived and non-BM-derived cells contribute to inflammasome activation in a MyD88-dependent manner in dietary steatohepatitis. We show that AIM2 inflammasome expression and activation are further augmented by TLR9 ligands in dietary steatohepatitis.
Exosomes, membranous nanovesicles, naturally carry bio-macromolecules and play pivotal roles in both physiological intercellular crosstalk and disease pathogenesis. Here, we showed that B cell-derived exosomes can function as vehicles to deliver exogenous miRNA-155 mimic or inhibitor into hepatocytes or macrophages, respectively. Stimulation of B cells significantly increased exosome production. Unlike in parental cells, baseline level of miRNA-155 was very low in exosomes derived from stimulated B cells. Exosomes loaded with a miRNA-155 mimic significantly increased miRNA-155 levels in primary mouse hepatocytes and the liver of miRNA-155 knockout mice. Treatment of RAW macrophages with miRNA-155 inhibitor loaded exosomes resulted in statistically significant reduction in LPS-induced TNFalpha production and partially prevented LPS-induced decrease in SOCS1 mRNA levels. Furthermore, exosome-mediated miRNA-155 inhibitor delivery resulted in functionally more efficient inhibition and less cellular toxicity compared to conventional transfection methods. Similar approaches could be useful in modification of target biomolecules in vitro and in vivo.
Persistent viral infection, such as HCV infection, is the result of the inability of the host immune system to mount a successful antiviral response, as well as the escape strategies devised by the virus. Although each individual component of the host immune system plays important roles in antiviral immunity, the interactive network of immune cells as a whole acts against the virus. The innate immune system forms the first line of host defense against viral infection, and thus, virus elimination or chronic HCV infection is linked to the direct outcome of the interactions between the various innate immune cells and HCV. By understanding how the distinct components of the innate immune system function both individually and collectively during HCV infection, potential therapeutic targets can be identified to overcome immune dysfunction and control chronic viral infection.
microRNA-122 regulates hypoxia-inducible factor-1 and vimentin in hepatocytes and correlates with fibrosis in diet-induced steatohepatitis
BACKGROUND and AIMS: miR-122 is the most abundant miRNA in the liver particularly in hepatocytes where it targets cholesterol metabolism. Steatosis, a key component of non-alcoholic fatty liver disease, is regulated by hypoxia-inducible factor-1alpha (HIF-1alpha). Here, we hypothesized that reduced miR-122 has a pathogenic role in steatohepatitis.
METHODS: miR-122 and its target genes were evaluated in mouse livers and/or isolated hepatocytes after methionine-choline-deficient (MCD) or methionine-choline-supplemented (MCS) diet.
RESULTS: Liver and hepatocyte miR-122 expression was significantly decreased in steatohepatitis. A maximum reduction in miR-122 occurred at the fibrosis stage (8 weeks of MCD diet). MAP3K3, a miR-122 target gene, was induced at all stages of non-alcoholic steatohepatitis (NASH; 3-8 weeks) only at the mRNA level. Increased NF-kappaB activation was found in MCD diet-fed mice and MAP3K3 regulated the NF-kappaB DNA binding in naive hepatocytes. HIF-1alpha mRNA and DNA binding and expression of the HIF-1alpha target gene, profibrotic lysyl oxidase, was increased in advanced steatohepatitis (8 weeks). In addition, increase in vimentin and Sirius red staining (liver fibrosis) was found at 8 weeks of MCD diet. Using miR-122 overexpression and inhibition approaches, we confirmed that HIF-1alpha, vimentin and MAP3K3 are novel miR-122 targets in hepatocytes. We report transcriptional repression of miR-122 in NASH. Decreased liver miR-122 was associated with elevated circulating miR-122 in both exosome-rich and protein-rich serum fractions.
CONCLUSIONS: Our novel data suggest that decreased liver miR-122 contributes to upregulation of modulators of tissue remodelling (HIF-1alpha, vimentin and MAP3K3) and might play a role in NASH-induced liver fibrosis.
AIM: To develop an animal model that encompasses the different facets of non-alcoholic steatohepatitis (NASH), which has been a challenge.
METHODS: In this study, we used a high fat diet (HFD) feeding supplemented with fructose and sucrose in the water mimicking the high-fructose corn syrup that is abundant in the diet in the United States. We used C57Bl/6 wild-type mice for short and long-term feedings of 6 and 16 wk respectively, and evaluated the extent of liver damage, steatosis, and inflammasome activation. Our methods included histopathological analysis to assess liver damage and steatosis, which involved H and E and oil-red-o staining; biochemical studies to look at ALT and triglyceride levels; RNA analysis using quantitative polymerase chain reaction; and cytokine analysis, which included the enzyme-linked immunosorbent assay method to look at interleukin (IL)-1beta and tumor necrosis factor-alpha (TNFalpha) levels. Furthermore, at each length of feeding we also looked at insulin resistance and glucose tolerance using insulin tolerance tests (ITT) and glucose tolerance tests.
RESULTS: There was no insulin resistance, steatosis, or inflammasome activation at 6 wk. In contrast, at 16 wk we found significant insulin resistance demonstrated by impaired glucose and ITT in male, but not female mice. In males, elevated alanine aminotransferase and triglyceride levels, indicated liver damage and steatosis, respectively. Increased liver TNFalpha and monocyte chemoattractant protein-1 mRNA and protein, correlated with steatohepatitis. The inflammasome components, adaptor molecule, Aim2, and NOD-like receptor 4, increased at the mRNA level, and functional inflammasome activation was indicated by increased caspase-1 activity and IL-1beta protein levels in male mice fed a long-term HFD. Male mice on HFD had increased alpha-smooth muscle actin and pro-collagen-1 mRNA indicating evolving fibrosis. In contrast, female mice displayed only elevated triglyceride levels, steatosis, and no fibrosis.
CONCLUSION: Our data indicate gender differences in NASH. Male mice fed a long-term HFD display steatohepatitis and inflammasome activation, whereas female mice have steatosis without inflammation.
Micro-RNA-155 Deficiency Prevents Alcohol-Induced Serum Endotoxin Increase and Small Bowel Inflammation in Mice
BACKGROUND: Chronic alcohol impairs gut barrier function and induces inflammatory cytokines. The effects of acute alcohol binge on the gut are partially understood. Micro-RNA-155 (miR-155), a modulator of cytokine and T-cell immune response in the gut, stabilizes tumor necrosis factor-alpha (TNFalpha) mRNA. Here, we investigated the role of the inflammation modulator miR-155 as well as the effects of acute binge and chronic alcohol feeding in the small bowel (SB) in mice.
METHODS: For the acute alcohol binge, wild-type (WT) mice received 5 g/kg 50% alcohol/d or equal amount of water oral gavage for 3 days. WT and miR-155-deficient (miR-155-knockout [KO]) mice received ethanol containing Lieber-DeCarli or isocaloric control diet for 5 weeks. MiR-155, antimicrobial peptide, regenerating islet-derived 3-beta (Reg3b), inflammation markers, Src homology 2-containing inositol phosphatase-1 (SHIP1), TNFalpha, and nuclear factor-kappaB (NF-kappaB) were measured in proximal intestinal tissue. Endotoxin was measured in the serum.
RESULTS: Acute alcohol binge enhanced, whereas chronic alcohol feeding decreased, Reg3b mRNA and protein levels in the SB. Both acute binge and chronic alcohol feeding increased serum endotoxin levels, intestinal NF-kappaB activation and TNFalpha mRNA levels. However, TNFalpha protein and miR-155 were increased only after chronic alcohol feeding in the SB. Furthermore, miR-155-KO mice were protected from chronic alcohol-induced increase in serum endotoxin, intestinal TNFalpha, and NF-kappaB activation. Also, alcohol-fed miR-155-KO mice had no decrease of Reg3b and SHIP1 levels.
CONCLUSIONS: These results demonstrate that both acute binge and chronic ethanol administration result in increased serum-endotoxin levels. Our study identifies a novel role for miR-155 in chronic alcohol-induced intestinal inflammation and barrier dysfunction.
An electronic health record-based intervention to increase follow-up office visits and decrease rehospitalization in older adults
OBJECTIVES: To assess the effect of an electronic health record-based transitional care intervention involving automated alerts to primary care providers and staff when older adults were discharged from the hospital.
DESIGN: Randomized controlled trial.
SETTING: Large multispecialty group practice.
PARTICIPANTS: Individuals aged 65 and older discharged from hospital to home.
INTERVENTION: In addition to notifying primary care providers about the individual's recent discharge, the system provided information about new drugs added during the inpatient stay, warnings about drug-drug interactions, recommendations for dose changes and laboratory monitoring of high-risk medications, and alerts to the primary care provider's support staff to schedule a posthospitalization office visit.
MEASUREMENTS: An outpatient office visit with a primary care provider after discharge and rehospitalization within 30 days after discharge.
RESULTS: Of the 1,870 discharges in the intervention group, 27.7% had an office visit with a primary care provider within 7 days of discharge. Of the 1,791 discharges in the control group, 28.3% had an office visit with a primary care provider within 7 days of discharge. In the intervention group, 18.8% experienced a rehospitalization within the 30-day period after discharge, compared with 19.9% in the control group. The hazard ratio for an office visit with a primary care physician did not significantly differ between the intervention and control groups. The hazard ratio for rehospitalization in the 30-day period after hospital discharge in the intervention versus the control group was 0.94 (95% confidence interval = 0.81-1.1).
CONCLUSION: This electronic health record-based intervention did not have a significant effect on the timeliness of office visits to primary care providers after hospitalization or risk of rehospitalization. Geriatrics Society.
Rates of insurance for injured patients before and after health care reform in Massachusetts: a possible case of double jeopardy
OBJECTIVES: We determined how preinjury insurance status and injury-related outcomes among able-bodied, community-dwelling adults treated at a Level I Trauma Center in central Massachusetts changed after health care reform.
METHODS: We compared insurance status at time of injury among non-Medicare-eligible adult Massachusetts residents before (2004-2005) and after (2009-2010) health care reform, adjusted for demographic and injury covariates, and modeled associations between insurance status and trauma outcomes.
RESULTS: Among 2148 patients before health care reform and 2477 patients after health care reform, insurance rates increased from 77% to 84% (P < .001). Younger patients, men, minorities, and penetrating trauma victims were less likely to be insured irrespective of time period. Uninsured patients were more likely to be discharged home without services (adjusted odds ratio = 3.46; 95% confidence interval = 2.65, 4.52) compared with insured patients.
CONCLUSIONS: Preinjury insurance rates increased for trauma patients after health care reform but remained lower than in the general population. Certain Americans may be in "double jeopardy" of both higher injury incidence and worse outcomes because socioeconomic factors placing them at risk for injury also present barriers to compliance with an individual insurance mandate.
BACKGROUND: Stroke is a major cause of morbidity and mortality. We describe trends in the incidence, outcomes, and risk factors for stroke in the US Medicare population from 1988 to 2008.
METHODS: We analyzed data from a 20% sample of hospitalized Medicare beneficiaries with a principal discharge diagnosis of ischemic (n = 918,124) or hemorrhagic stroke (n = 133,218). Stroke risk factors were determined from the National Health and Nutrition Examination Survey (years 1988-1994, 2001-2008) and medication uptake from the Medicare Current Beneficiary Survey (years 1992-2008). Primary outcomes were stroke incidence and 30-day mortality after stroke hospitalization.
RESULTS: Ischemic stroke incidence decreased from 927 per 100,000 in 1988 to 545 per 100,000 in 2008, and hemorrhagic stroke decreased from 112 per 100,000 to 94 per 100,000. Risk-adjusted 30-day mortality decreased from 15.9% in 1988 to 12.7% in 2008 for ischemic stroke and from 44.7% to 39.3% for hemorrhagic stroke. Although observed stroke rates decreased, the Framingham stroke model actually predicted increased stroke risk (mean stroke score 8.3% in 1988-1994, 8.8% in 2005-2008). Statin use in the general population increased (4.0% in 1992, 41.4% in 2008), as did antihypertensive use (53.0% in 1992, 73.5% in 2008).
CONCLUSIONS: Incident strokes in the Medicare population aged >/=65 years decreased by approximately 40% over the last 2 decades, a decline greater than expected on the basis of the population's stroke risk factors. Case fatality from stroke also declined. Although causality cannot be proven, declining stroke rates paralleled increased use of statins and antihypertensive medications.
Long-term survival for patients with acute decompensated heart failure according to ejection fraction findings
Limited data exist about the long-term prognosis of patients with acute decompensated heart failure (ADHF) further stratified according to ejection fraction (EF) findings. The primary objective of this population-based observational study was to characterize and compare trends in long-term prognosis after an episode of ADHF across 3 EF strata. Hospital medical records were reviewed for 3,604 residents of the Worcester, Massachusetts, metropolitan area who were discharged after ADHF from all 11 medical centers in central Massachusetts during 1995, 2000, 2002, and 2004 and had EF measurements during their index hospitalizations. The average age of this population was 75 years, most were white, and 44% were men. Approximately 49% of the population had heart failure (HF) with preserved EF (EF >/=50%), 37% had HF with reduced EF (EF
A review of the published literature found 60 congenital and acquired disorders with symptoms that include psychosis in youth. The prevalence, workup, genetics, and associated neuropsychiatric features of each disorder are described. Eighteen disorders (30%) have distinct phenotypes (doorway diagnoses); 18 disorders (30%) are associated with intellectual disability; and 43 disorders (72%) have prominent neurologic signs. Thirty-one disorders (52%) can present without such distinct characteristics, and are thus more easily overlooked. A systematic and cost-effective differential diagnostic approach based on estimated prevalence and most prominent associated signs is recommended.