Hepatitis C virus core protein induces hepatic steatosis via Sirt1-dependent pathway

Beyond genotype-4: Direct-acting antiviral agents in patients with chronic hepatitis C infection from the Eastern Province of Saudi Arabia

Background and Aims

Direct-acting antiviral agents (DAAs) have revolutionized the treatment of patients with chronic hepatitis C virus (HCV) infection, resulting in a high sustained virologic response (SVR) rate. However, the published data from the Eastern Province of Saudi Arabia are limited to small patient groups and specific DAAs used for patients with genotype-4.(GT-4). This study aimed to investigate the effectiveness and safety of DAAs for treating HCV infection in Saudi Arabia in a real-life setting.

Methods

This retrospective study from January 2015 to December 2019 included all HCV-infected patients who received DAAs at a tertiary university hospital in Saudi Arabia. Baseline characteristics and laboratory data were collected from health records, including HCV RNA level, genotype, and presence of liver cirrhosis or steatosis. The primary outcome was undetectable HCV RNA at 12 weeks posttreatment (SVR12). Results were stratified based on different DAAs and HCV genotypes. Treatment-related adverse events were recorded. Statistical analyses were performed using SPSS version 25.0.

Results

Of the 117 patients included, 43.2% had advanced fibrosis or cirrhosis, and the majority (90.6%) were treatment-naïve. The mean age was 50.1 ± 15.5 years, with 57.3% females. The most common genotype was GT-4 (44.4%), followed by GT-1 (40.2%). Most patients (64.3%) received sofosbuvir and daclatasvir ± ribavirin, while the remaining patients received various DAAs. Overall, 98.3% of the patients achieved SVR12. The therapy was well tolerated, with fatigue and headache being the most common side effects.

Conclusions

Treatment with DAAs is highly effective across different genotypes and various DDA regimens in the real world for treating HCV infection in the Eastern Province of Saudi Arabia, contributing to improved patient outcomes and the overall goal of HCV elimination.

NAFLD is associated with less severe liver fibrosis in chronic hepatitis B: A multi-center, retrospective study

INTRODUCTION AND OBJECTIVES

Chronic hepatitis B (CHB) may progress to more serious liver diseases and it is often accompanied by non-alcoholic fatty liver disease (NAFLD). NAFLD and CHB share risk factors for liver fibrosis and cirrhosis, but the influence of NAFLD on fibrosis progression is controversial. This retrospective study evaluated the prevalence of NAFLD in patients with CHB and investigated associations between NAFLD and liver fibrosis in a large multi-center cohort of hepatitis B patients submitted to liver biopsy.

PATIENTS AND METHODS

Treatment-naïve patients with CHB who underwent liver biopsy were analyzed. Propensity score matching (PSM) was performed to adjust the confounders between patients with and without NAFLD.

RESULTS

A total of 1496 CHB patients were included. Two hundred and ninety (19.4%) patients were diagnosed with NAFLD by liver biopsy. The proportions of significant liver fibrosis (52.8% vs. 63.9%, P<0.001), advanced liver fibrosis (27.2% vs. 36.5%, P=0.003), and cirrhosis (13.4% vs. 19.7%, P=0.013) was considerably lower in CHB patients with NAFLD compared to those without NAFLD. 273 patients were included in each group after PSM adjusted for age, sex, hepatitis B envelope antigen status, and hepatitis B virus DNA. Liver fibrosis remained less severe in CHB patients with NAFLD than those without NAFLD (P<0.05) after PSM. The presence of NAFLD was considered an independent negative factor of significant liver fibrosis (odds ratio (OR) 0.692, P=0.013) and advanced liver fibrosis (OR 0.533, P = 0.002) in CHB patients.

CONCLUSIONS

NAFLD is not uncommon in CHB patients with the prevalence of 19.4%. The presence of NAFLD is associated with less severe liver fibrosis in CHB patients.

REGISTRATION NO

OF THE STUDY/TRIAL

NCT03097952.

Sirtuins: Key pieces in the host response to pathogens' puzzle

Global warming is changing the distribution of different pathogens around the globe, and humans are more susceptible to new or re-emerging infections. The human response to microbes is complex and involves different mechanisms of the immune system. Regulation of gene expression of immunity genes and of metabolism of immune cells are essential in this process. Both mechanisms could be regulated by protein lysine acetylation that will control chromatin structure affecting gene expression or key enzyme activity involved in cellular processes. Protein acetylation is crucial for the immunity and involves two families of enzymes: lysine acetyltransferases (KATs), which will promote protein acetylation, and lysine deacetylases (KDACs) that will reduce this modification. Lysine deacetylases are divided into Zinc-dependent or HDACs and NAD⁺ -dependent, or Sirtuins. These enzymes are in the nucleus, cytosol, and mitochondria of mammalian cells affecting different cellular pathways, such as metabolism, gene expression, DNA repair, cell proliferation, and apoptosis, opening the opportunity to explore these proteins as drug targets in different diseases, including cancer and neurodegenerative illness. Although widely explored in chronic diseases, very little is known about the role of Sirtuins during host response against microbes' infection. In this review we aim to explore the most recent literature evidencing a role for these enzymes during host responses to viruses, bacterial and protozoan infections, pointing out how these proteins can be manipulated by these pathogens to progress in the infection. Moreover, we will uncover the potential of host KDACs as therapeutic targets to prevent infections by activating effector immune functions.

The sirtuin family in health and disease

Sirtuins (SIRTs) are nicotine adenine dinucleotide(+)-dependent histone deacetylases regulating critical signaling pathways in prokaryotes and eukaryotes, and are involved in numerous biological processes. Currently, seven mammalian homologs of yeast Sir2 named SIRT1 to SIRT7 have been identified. Increasing evidence has suggested the vital roles of seven members of the SIRT family in health and disease conditions. Notably, this protein family plays a variety of important roles in cellular biology such as inflammation, metabolism, oxidative stress, and apoptosis, etc., thus, it is considered a potential therapeutic target for different kinds of pathologies including cancer, cardiovascular disease, respiratory disease, and other conditions. Moreover, identification of SIRT modulators and exploring the functions of these different modulators have prompted increased efforts to discover new small molecules, which can modify SIRT activity. Furthermore, several randomized controlled trials have indicated that different interventions might affect the expression of SIRT protein in human samples, and supplementation of SIRT modulators might have diverse impact on physiological function in different participants. In this review, we introduce the history and structure of the SIRT protein family, discuss the molecular mechanisms and biological functions of seven members of the SIRT protein family, elaborate on the regulatory roles of SIRTs in human disease, summarize SIRT inhibitors and activators, and review related clinical studies.

Tenovin-1 inhibited dengue virus replication through SIRT2

Dengue fever is a common arbovirus disease, which has been spread to the entire tropical world. At present, effective drugs for the treatment of dengue fever have not yet appeared, and the dengue vaccines studied in various countries have also experienced severe adverse reactions. Thus it is urgent to find new chemicals against dengue virus. Now we found Sirtuins (SIRTs) were increased during dengue virus infection and tenovin-1, a SIRT1/2 inhibitor, showed an impressive antiviral ability in vitro. In BHK-21 cells, tenovin-1 inhibited the replication of DENV2 with an EC50 at 3.41 ± 1.10 μM, also inhibited other three types of dengue viruses with EC50 at 0.97 ± 1.11 μM, 1.81 ± 1.08 μM, 3.81 ± 1.34 μM respectively. Moreover, the cytopathic effect-induced DENV2 was largely improved by tenovin-1 treatment and the release of progeny viruses was inhibited by tenovin-1 treatment. At the same time, the viral protein level and mRNA level were decreased with tenovin-1 treatment after dengue virus infection. From the drug-addition assay, the tenovin-1 played its antiviral after viral infection, which indicated tenovin-1 was not a microbicide. Apart from its antiviral effect, tenovin-1 inhibited the inflammatory response caused by DENV2, reducing the release of inflammatory factors during viral infection. The antiviral effect of tenovin-1 was abrogated with SIRT agonist or SIRT2 knockdown treatment, which indicated the effect of tenovin-1 was on-target. In conclusion, tenovin-1 was proved to be a promising compound against flavivirus infection through SIRT2, which should be pay more attention for further study.

NAD+ Degrading Enzymes, Evidence for Roles During Infection

Declines in cellular nicotinamide adenine dinucleotide (NAD) contribute to metabolic dysfunction, increase susceptibility to disease, and occur as a result of pathogenic infection. The enzymatic cleavage of NAD⁺ transfers ADP-ribose (ADPr) to substrate proteins generating mono-ADP-ribose (MAR), poly-ADP-ribose (PAR) or O-acetyl-ADP-ribose (OAADPr). These important post-translational modifications have roles in both immune response activation and the advancement of infection. In particular, emergent data show viral infection stimulates activation of poly (ADP-ribose) polymerase (PARP) mediated NAD⁺ depletion and stimulates hydrolysis of existing ADP-ribosylation modifications. These studies are important for us to better understand the value of NAD⁺ maintenance upon the biology of infection. This review focuses specifically upon the NAD⁺ utilising enzymes, discusses existing knowledge surrounding their roles in infection, their NAD⁺ depletion capability and their influence within pathogenic infection.

Obeticholic acid ameliorates obesity and hepatic steatosis by activating brown fat

Obeticholic acid (OCA) is exemplified as a potent drug for treating primary biliary cirrhosis and nonalcoholic fatty liver disease by inhibiting bile acid synthesis. However, it remains unclear whether the effect of OCA is mediated by the function of brown adipose tissue (BAT). In the present study, brown adipogenesis differentiation in vitro and db/db mouse model treated with OCA were used to assess the anti-obesity function by body weight tracking, O₂ consumption, food intake, physical activity, glucose tolerance tests. In addition, uncoupling protein 1 (Ucp1) protein expression in brown adipose tissue was measured by western blotting, morphometry of brown adipose tissue was analyzed by hematoxylin and eosin staining. Hepatic steatosis was detected by Oil-Red O staining and serological analysis was performed to assess the effect of OCA on hyperlipidemia. OCA treatment enhanced brown adipocyte cell differentiation and upregulated the expression of the BAT-specific gene Ucp1) in C3H10T1/2 cells in vitro. Consistent with these findings, OCA increased whole-body energy metabolism and glucose homeostasis by enhancing BAT activity in vivo, and ultimately decreased body weight gain in db/db mice. In addition, the results demonstrated that spontaneous hepatic steatosis in db/db mice was ameliorated following OCA treatment. In summary, OCA functioned as a BAT activator to help ameliorate obesity and maintain glucose homeostasis in db/db mice. The present results may provide a novel potential therapeutic approach to activate brown fat in patients with obesity and other metabolic disorders.

Reduced hepatic steatosis is associated with higher risk of hepatocellular carcinoma in chronic hepatitis B infection

BACKGROUND

Concomitant chronic hepatitis B infection (CHB) and non-alcoholic fatty liver disease (NAFLD) is common, but the implications of NAFLD on clinical outcomes of CHB, including hepatocellular carcinoma (HCC), are not well-investigated.

METHODS

CHB patients were recruited for transient elastography assessment for liver stiffness (LS), and controlled attenuation parameter (CAP), a non-invasive quantification of hepatic steatosis, and were prospectively followed up for development of HCC. Steatosis and severe steatosis were diagnosed by CAP ≥ 248 dB/m and ≥ 280 dB/m respectively, and advanced fibrosis/cirrhosis was diagnosed by LS ≥ 9 kPa. The independent effect of hepatic steatosis on HCC was examined via propensity score matching (PSM) of LS and other significant clinical variables.

RESULTS

Forty-eight patients developed HCC among 2403 CHB patients (55.6% male, median age 55.6 years, 57.1% antiviral-treated, median ALT 26 U/L) during a median follow-up of 46.4 months. Multivariate Cox regression analysis showed age (HR 1.063), male (HR 2.032), Albumin-Bilirubin score (HR 2.393) and CAP (HR 0.993) were associated with HCC development. The cumulative probability of HCC was 2.88%, 1.56% and 0.71%, respectively for patients with no steatosis, mild-to-moderate steatosis, and severe steatosis, respectively (p = 0.01). The risk of HCC increased from 1.56 to 8.89% in patients without severe steatosis if advanced fibrosis/cirrhosis was present (p < 0.001). PSM yielded 957 pairs of CHB patients and hepatic steatosis was independently associated with HCC (HR 0.41).

CONCLUSION

Reduced hepatic steatosis was significantly associated with a higher risk of incident HCC in CHB infection. Routine CAP and LS measurements are important for risk stratification.

Allicin Regulates Energy Homeostasis through Brown Adipose Tissue

Brown adipose tissue (BAT) is a promising potential therapeutic target for the treatment of obesity and related metabolic diseases. Allicin, a natural product in garlic, has multiple biological and pharmacological functions. However, the role of allicin in the regulation of metabolic organs, particularly BAT activation, has not been well studied. Here, we show that allicin imparts a significant effect by inhibiting body weight gain, decreasing adiposity, maintaining glucose homeostasis, improving insulin resistance, and ameliorating hepatic steatosis in obese mice. These observations strongly correlate with the activation of BAT. Notably, allicin plays a role in BAT activation, which may partly contribute to the Sirt1-PGC1α-Tfam pathway. In addition, allicin can significantly increase the succinylation levels of UCP1 in BAT by inhibiting sirt5, whereas excess allicin induces autophagy/mitophagy and mitochondrial dysfunction. Thus, our findings point to allicin as a promising therapeutic approach for the treatment of obesity and metabolic disorders.

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Allicin reduces adiposity and maintains glucose homeostasis

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Allicin activates the brown adipocytes and increases the energy expenditure

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Allicin enhances BAT activity partly through SIRT1-PGC1a-Tfam signaling pathway

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Allicin regulates mitophagy via suppressed sirt5-mediated succinylation accumulation

XTP8 promotes hepatocellular carcinoma growth by forming a positive feedback loop with FOXM1 oncogene

Hepatocellular carcinoma (HCC) is one of the most common cancer in the world and the main cause of cancer death. Chronic hepatitis B virus (HBV) infection is the major cause of HCC. HBx, as a transactivator, plays an important role in the occurrence and development process of HCC leading by HBV infection. XTP8, related to HBx, however, there are no studies on the function of XTP8 in HCC. In our research, we demonstrated that XTP8 was significantly up-regulated in HCC tissues compared with non-cancerous tissues in Oncomine, TCGA and GEO database. Moreover, Kaplan-Meier Plotter analysis indicated that patients with higher XTP8 expression had significantly lower overall survival. Our immunohistochemical results suggested that XTP8 protein expression in HCC tissues was dramatically higher compared with control normal tissues. In vivo xenograft experiments on nude mice, the overexpression of XTP8 promoted the tumorigenic ability of HepG2 cells. In HepG2 and Huh7 cells, XTP8 upregulated FOXM1 expression to promote cell proliferation and inhibited cell apoptosis. FOXM1 knockdown reduced promoter activity of XTP8 to downregulate XTP8 expression. Thiostrepton, an inhibitor of FOXM1, decreased XTP8 expression. Therefore, our study demonstrates that XTP8 is a valuable prognostic predictor for HCC and there is a novel positive regulatory feedback loop between XTP8 and FOXM1 promoting the development of HCC.

Fluvastatin Sodium Ameliorates Obesity through Brown Fat Activation

Brown adipose tissue (BAT), an organ that burns energy through uncoupling thermogenesis, is a promising therapeutic target for obesity. However, there are still no safe anti-obesity drugs that target BAT in the market. In the current study, we performed large scale screening of 636 compounds which were approved by Food and Drug Administration (FDA) to find drugs that could significantly increase uncoupling protein 1 (UCP1) mRNA expression by real-time PCR. Among those UCP1 activators, most of them were antibiotics or carcinogenic compounds. We paid particular attention to fluvastatin sodium (FS), because as an inhibitor of the cellular hydroxymethyl glutaryl coenzyme A (HMG-CoA) reductase, FS has already been approved for treatment of hypercholesteremia. We found that in the cellular levels, FS treatment significantly increased UCP1 expression and BAT activity in human brown adipocytes. Consistently, the expression of oxidative phosphorylation-related genes was significantly increased upon FS treatment without differences in adipogenic gene expression. Furthermore, FS treatment resisted to high-fat diet (HFD)-induced body weight gain by activating BAT in the mice model. In addition, administration of FS significantly increased energy expenditure, improved glucose homeostasis and ameliorated hepatic steatosis. Furthermore, we reveal that FS induced browning in subcutaneous white adipose tissue (sWAT) known to have a beneficial effect on energy metabolism. Taken together, our results clearly demonstrate that as an effective BAT activator, FS may have great potential for treatment of obesity and related metabolic disorders.

Hepatitis B virus infection and risk of non-alcoholic fatty liver disease: A population-based cohort study

BACKGROUND & AIMS

Although non-alcoholic fatty liver disease (NAFLD) has been studied extensively, the potential risk factors for NAFLD among chronic hepatitis B (CHB) patients have not been fully known.

METHODS

A population-based cohort of adult CHB patients without a history of alcohol drinking or NAFLD were recruited and followed up from October 2012 to January 2015 in Jiangsu province, China. Using Cox proportional hazards regression model, potential risk factors including viral and metabolic factors for NAFLD were evaluated.

RESULTS

Two thousand three hundred and ninety-three adult CHB patients (mean age 50.7 ± 13.2 years) were included in the cohort. With 4429 person-years of follow-up, 283 individuals progressed to NAFLD with an incidence rate of 63.89/1000 person-years. Overweight and obese CHB patients had an increased risk of NAFLD (overweight adjusted hazard ratio [HR], 3.10; 95% CI, 2.29-4.18; obese HR, 8.52; 95%CI, 5.93-12.25) compared to normal weight carriers. The incidence of NAFLD was associated with concurrent type 2 diabetes mellitus (DM) (HR, 1.88; 95%CI, 1.15-3.08). However, no associations between viral factors with NAFLD incidence rate were identified. In a subgroup of participants with concurrent type 2 DM, detectable HBV DNA levels were negatively associated with the development of NAFLD (HR, 0.37; 95%CI, 0.14-0.98). There was super-multiplicative interaction between BMI and gender with respect to incidence of NAFLD, with an ROR of 2.08 (95%CI, 1.02-4.23).

CONCLUSION

Metabolic factors play an important role in the presence of NAFLD among Chinese CHB patients. However, viral replication factors are not related to NAFLD except among those with concurrent type 2 DM.