C-X-C motif chemokine 10 in non-alcoholic steatohepatitis: role as a pro-inflammatory factor and clinical implication

Inflammation in liver fibrosis and atrial fibrillation: A prospective population-based proteomic study

Background & Aims

Elevated liver stiffness has been associated with atrial fibrillation (AFib) in the general population. The mechanism underlying this association is unclear.

Methods

Participants were recruited from the general population and prospectively enrolled with follow-up for 5 years. The fibrosis-4 (FIB-4) index was used as a surrogate marker for liver fibrosis. Proteomics analysis was performed using the 92-target Olink inflammation panel. Validation was performed using the NAFLD fibrosis score (NFS), aspartate aminotransferase to platelet index (APRI), and repeat confirmation proteomics.

Results

A sample of 11,509 participants with a mean age of 54.0 ± 11.1 years, 51.3% women, and a median FIB-4 index of 0.85 (0.65/1.12), was used. The FIB-4 index was predictive for prevalent (FIB-4 index adjusted odds ratio (aOR) per SD: 1.100 with 95% CI 1.011-1.196; p = 0.026), but not incident AFib (log[FIB-4 index]) adjusted hazard ratio: 1.125 with 95% CI 0.943-1.342, p = 0.19). Elastic net regularized regression identified CCL20, DNER, and CXCL10 for prevalent AFib, and AXIN1, CXCL10, and Flt3L for the log(FIB-4 index) (per SD) as most important in common regulated proteins. The relationship between the FIB-4 index, the identified proteins, and AFib was relevant and reproduced at the 5-year follow-up for CXCL10 after adjusting for confounders (log[FIB-4 index] per SD - CXCL10 [per SD] adjusted β 0.160 with 95% CI 0.127-0.194, p <0.0001; CXCL10 [per SD] - AFib aOR 1.455 with 95% CI 1.217-1.741, p <0.0001), reproduced using the NFS and APRI, and corresponding to increased serum levels.

Conclusions

CXCL10 is linked to liver fibrosis, as determined by the FIB-4 index, and to prevalent AFib.

Impact and implications

How elevated liver stiffness relates to atrial fibrillation in the general population remains to be clarified. We hypothesized that systemic inflammation against a background of liver fibrosis produced from metabolic dysfunction-associated steatotic liver disease (MASLD), is involved in the pathophysiology of atrial fibrillation. Using large-scale targeted proteomics, we found that CXCL10 is related to both liver fibrosis, as defined by the fibrosis-4 index, and to atrial fibrillation. These results can aid evidence-based drug development for patients with atrial fibrillation and MASLD-related liver fibrosis.

Role of the type 3 cytokines IL-17 and IL-22 in modulating metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) comprises a spectrum of liver diseases that span simple steatosis, metabolic dysfunction-associated steatohepatitis (MASH) and fibrosis and may progress to cirrhosis and cancer. The pathogenesis of MASLD is multifactorial and is driven by environmental, genetic, metabolic and immune factors. This review will focus on the role of the type 3 cytokines IL-17 and IL-22 in MASLD pathogenesis and progression. IL-17 and IL-22 are produced by similar adaptive and innate immune cells such as Th17 and innate lymphoid cells, respectively. IL-17-related signaling is upregulated during MASLD resulting in increased chemokines and proinflammatory cytokines in the liver microenvironment, enhanced recruitment of myeloid cells and T cells leading to exacerbation of inflammation and liver disease progression. IL-17 may also act directly by activating hepatic stellate cells resulting in increased fibrosis. In contrast, IL-22 is a pleiotropic cytokine with a dominantly protective signature in MASLD and is currently being tested as a therapeutic strategy. IL-22 also exhibits beneficial metabolic effects and abrogates MASH-related inflammation and fibrosis development via inducing the production of anti-oxidants and anti-apoptotic factors. A sex-dependent effect has been attributed to both cytokines, most importantly to IL-22 in MASLD or related conditions. Altogether, IL-17 and IL-22 are key effectors in MASLD pathogenesis and progression. We will review the role of these two cytokines and cells that produce them in the development of MASLD, their interaction with host factors driving MASLD including sexual dimorphism, and their potential therapeutic benefits.

Lauric acid attenuates hepato-metabolic complications and molecular alterations in high-fat diet-induced nonalcoholic fatty liver disease in rats

Nonalcoholic fatty liver disease (NAFLD) has emerged as a major chronic liver illness characterized by increase of lipid content in the liver. This study investigated the role of lauric acid to treat NAFLD in male adult Sprague Dawley rats. In this study, to induce NAFLD in the rats, a high-fat diet (HFD) was administered for eight consecutive weeks. Lauric acid groups received lauric acid (250 and 500 mg/kg; orally), concurrently with HFD for eight consecutive weeks. Lauric acid could ameliorate the serum levels of TG, TC, ALT, AST, blood glucose, and insulin. Moreover, lauric acid significantly elevated the levels of SOD, GSH, catalase, and IL-10. Additionally, it lowered the hepatic levels of MDA, ROS, MPO, 4-HNE, interleukin (IL)-1β, and tumor necrosis factor (TNF-α). Furthermore, lauric acid significantly up-regulated the hepatic expression of IRS1, AMPK, PI3K, and SIRT1 genes. In parallel, lauric acid could improve the histopathological picture of the liver and reduce the liver apoptosis via decreasing the expression of annexin V (Anx V). Finally, our data proposed that lauric acid could be an effective candidate for the NAFLD treatment.

Inflammatory Protein Signatures as Predictive Disease-Specific Markers for Non-Alcoholic Steatohepatitis (NASH)

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic disease worldwide, consisting of a broad spectrum of diseases such as simple steatosis (NAFL), non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and hepatocellular carcinoma. Hepatic inflammation plays a key role in the pathophysiology of NAFLD. Inflammatory mediators such as cytokines and chemokines are considered as contributing factors to NAFLD development and progression. In the present study, we aimed to investigate the inflammatory protein signatures as predictive disease-specific markers for non-alcoholic fatty liver disease (NAFLD). This cross-sectional study included healthy control (n = 64), NAFL (n = 109), and NASH (n = 60) human subjects. Serum concentrations of various cytokines and chemokines were evaluated using sensitive multiplex assays. We used principal component analysis (PCoA) to reveal distinct differences in the levels of cytokines and chemokines between each of the study groups. Further, a random forest classification model was developed to identify the panel of markers that could predict diseases. The protein-protein network analysis was performed to determine the various signaling pathways associated with the disease-specific panel of markers. Serum concentrations of TNF-α, IL-1β, IL-1ra, G-CSF, PDGF-BB, MCP-1, MIP-1a, MIP-1b, RANTES, eotaxin, IL-8 and IP-10 were significantly increased in NASH group as compared to control group. Furthermore, serum concentrations of IL-9 and IL-13 were significantly lower in the NASH group, whereas IL-2 levels were significantly decreased in the NAFL group when compared to the control group. PCoA results demonstrated statistically significant differences in cytokines and chemokines between each of the study groups (PERMANOVA p = 0.001; R2 = 0.102). RANTES, IL-1ra, MIP-1b, IL-2, and G-CSF could differentiate the NAFL group from the controls; G-CSF, IL-1ra, TNF-α, RANTES, and IL-9 could differentiate the NASH group from the controls; and G-CSF, IL-9, IL-13, eotaxin, and TNF- α could differentiate the NASH group from the NAFL group. Our protein-protein network revealed that these markers are involved in cytokine-cytokine receptor interaction, Th1 and Th2 cell differentiation, TNF, chemokine, JAK/STAT, P13K/Akt, TLR, NOD-like receptor, NF-kB, and adipocytokine signaling pathways which might be responsible for disease pathogenesis. Our study findings revealed a set of distinct cytokine and chemokine markers and they might be considered as biomarkers in distinguishing NASH from NAFL. Future multicentre studies with larger sample size are recommended to determine the potential utility of these panels of markers.

Inflammatory liver diseases and susceptibility to sepsis

Patients with inflammatory liver diseases, particularly alcohol-associated liver disease and metabolic dysfunction-associated fatty liver disease (MAFLD), have higher incidence of infections and mortality rate due to sepsis. The current focus in the development of drugs for MAFLD is the resolution of non-alcoholic steatohepatitis and prevention of progression to cirrhosis. In patients with cirrhosis or alcoholic hepatitis, sepsis is a major cause of death. As the metabolic center and a key immune tissue, liver is the guardian, modifier, and target of sepsis. Septic patients with liver dysfunction have the highest mortality rate compared with other organ dysfunctions. In addition to maintaining metabolic homeostasis, the liver produces and secretes hepatokines and acute phase proteins (APPs) essential in tissue protection, immunomodulation, and coagulation. Inflammatory liver diseases cause profound metabolic disorder and impairment of energy metabolism, liver regeneration, and production/secretion of APPs and hepatokines. Herein, the author reviews the roles of (1) disorders in the metabolism of glucose, fatty acids, ketone bodies, and amino acids as well as the clearance of ammonia and lactate in the pathogenesis of inflammatory liver diseases and sepsis; (2) cytokines/chemokines in inflammatory liver diseases and sepsis; (3) APPs and hepatokines in the protection against tissue injury and infections; and (4) major nuclear receptors/signaling pathways underlying the metabolic disorders and tissue injuries as well as the major drug targets for inflammatory liver diseases and sepsis. Approaches that focus on the liver dysfunction and regeneration will not only treat inflammatory liver diseases but also prevent the development of severe infections and sepsis.

Immune Features of Disparate Liver Transplant Outcomes in Female Hispanics With Nonalcoholic Steatohepatitis

Background

Nonalcoholic steatohepatitis (NASH) is a severe immune-mediated stage of nonalcoholic fatty liver disease that is rapidly becoming the most common etiology requiring liver transplantation (LT), with Hispanics bearing a disproportionate burden. This study aimed to uncover the underlying immune mechanisms of the disparities experienced by Hispanic patients undergoing LT for NASH.

Methods

We enrolled 164 LT recipients in our institutional review board-approved study, 33 of whom presented with NASH as the primary etiology of LT (20%), with 16 self-reported as Hispanic (48%). We investigated the histopathology of prereperfusion and postreperfusion biopsies, clinical liver function tests, longitudinal soluble cytokines via 38-plex Luminex, and immune cell phenotypes generated by prereperfusion and postreperfusion blood using 14-color flow cytometry and enzyme-linked immunosorbent assay.

Results

Hispanic LT recipients transplanted for NASH were disproportionately female (81%) and disproportionately suffered poor outcomes in the first year posttransplant, including rejection (26%) and death (38%). Clinically, we observed increased pro-inflammatory and apoptotic histopathological features in biopsies, increased AST/international normalized ratio early posttransplantation, and a higher incidence of presensitization to mismatched HLA antigens expressed by the donor allograft. Experimental investigations revealed that blood from female Hispanic NASH patients showed significantly increased levels of leukocyte-attracting chemokines, innate-to-adaptive switching cytokines and growth factors, HMGB1 release, and TLR4/TLR8/TLR9/NOD1 activation, and produced a pro-inflammatory, pro-apoptotic macrophage phenotype with reduced CD14/CD68/CD66a/TIM-3 and increased CD16/CD11b/HLA-DR/CD80.

Conclusions

A personalized approach to reducing immunological risk factors is urgently needed for this endotype in Hispanics with NASH requiring LT, particularly in females.

A narrative review: CXC chemokines influence immune surveillance in obesity and obesity-related diseases: Type 2 diabetes and nonalcoholic fatty liver disease

Adipose tissue develops lipids, aberrant adipokines, chemokines, and pro-inflammatory cytokines as a consequence of the low-grade systemic inflammation that characterizes obesity. This low-grade systemic inflammation can lead to insulin resistance (IR) and metabolic complications, such as type 2 diabetes (T2D) and nonalcoholic fatty liver disease (NAFLD). Although the CXC chemokines consists of numerous regulators of inflammation, cellular function, and cellular migration, it is still unknown that how CXC chemokines and chemokine receptors contribute to the development of metabolic diseases (such as T2D and NAFLD) during obesity. In light of recent research, the objective of this review is to provide an update on the linkage between the CXC chemokine, obesity, and obesity-related metabolic diseases (T2D and NAFLD). We explore the differential migratory and immunomodulatory potential of CXC chemokines and their mechanisms of action to better understand their role in clinical and laboratory contexts. Besides that, because CXC chemokine profiling is strongly linked to leukocyte recruitment, macrophage recruitment, and immunomodulatory potential, we hypothesize that it could be used to predict the therapeutic potential for obesity and obesity-related diseases (T2D and NAFLD).

FABP4 in LSECs promotes CXCL10-mediated macrophage recruitment and M1 polarization during NAFLD progression

BACKGROUND AND AIMS

Non-alcoholic liver disease (NAFLD) is emerging as the leading cause of end-stage liver disease with a serious threat to global health burden. Fatty acid-binding protein 4 (FABP4) is closely associated with metabolic syndromes. We aimed to explore the potential mechanisms of FABP4 in NAFLD progression.

MATERIALS AND METHODS

For NAFLD mice, animals were fed with high fat diet (HFD) for 20 weeks. The assays of hematoxylin and eosin, Sirius Red, oil red O staining and immunohistology were performed to evaluate hepatic pathology. Flow cytometric analysis was used to distinguish macrophage subtypes.

RESULTS

Serum FABP4 level was positively correlate with the severity of hepatic steatosis in NAFLD patients. FABP4 expression was mainly distributed in liver sinusoidal endothelial cells (LSECs), which was significantly increased in HFD mice. The level of CXCL10 was positively correlated with FABP4 at mRNA and serum level. FABP4 inhibition resulted in decreased expression of CXCL10. The percentage of M1 macrophage and CXCR3⁺ cells in infiltrated macrophage was increased in liver of HFD mice. Inhibition of FABP4 ameliorated HFD-induced M1 macrophage polarization as well as CXCR3⁺ macrophages recruitment. Recombinant CXCL10 and co-culturing with TMNK-1 stimulated macrophage toward M1 polarization, which could be reversed by CXCR3 inhibitor. Palmitic acid treatment resulted in increased nuclear P65 expression, which could be reversed by inhibiting FABP4. Cxcl10 expression was dramatically suppressed by NF-κB inhibitor.

CONCLUSIONS

FABP4 in LSECs may play a pathogenic role in NAFLD course by promoting CXCL10-mediated macrophage M1 polarization and CXCR3⁺ macrophage infiltration via activating NF-κB/p65 signaling.

Identification of Hub Genes and Biological Mechanisms Associated with Non-Alcoholic Fatty Liver Disease and Triple-Negative Breast Cancer

The relationship between non-alcoholic fatty liver disease (NAFLD) and triple-negative breast cancer (TNBC) has been widely recognized, but the underlying mechanisms are still unknown. The objective of this study was to identify the hub genes associated with NAFLD and TNBC, and to explore the potential co-pathogenesis and prognostic linkage of these two diseases. We used GEO, TCGA, STRING, ssGSEA, and Rstudio to investigate the common differentially expressed genes (DEGs), conduct functional and signaling pathway enrichment analyses, and determine prognostic value between TNBC and NAFLD. GO and KEGG enrichment analyses of the common DEGs showed that they were enriched in leukocyte aggregation, migration and adhesion, apoptosis regulation, and the PPAR signaling pathway. Fourteen candidate hub genes most likely to mediate NAFLD and TNBC occurrence were identified and validation results in a new cohort showed that ITGB2, RAC2, ITGAM, and CYBA were upregulated in both diseases. A univariate Cox analysis suggested that high expression levels of ITGB2, RAC2, ITGAM, and CXCL10 were associated with a good prognosis in TNBC. Immune infiltration analysis of TNBC samples showed that NCF2, ICAM1, and CXCL10 were significantly associated with activated CD8 T cells and activated CD4 T cells. NCF2, CXCL10, and CYBB were correlated with regulatory T cells and myeloid-derived suppressor cells. This study demonstrated that the redox reactions regulated by the NADPH oxidase (NOX) subunit genes and the transport and activation of immune cells regulated by integrins may play a central role in the co-occurrence trend of NAFLD and TNBC. Additionally, ITGB2, RAC2, and ITGAM were upregulated in both diseases and were prognostic protective factors of TNBC; they may be potential therapeutic targets for treatment of TNBC patients with NAFLD, but further experimental studies are still needed.

Transcriptome changes in stages of non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the United States and globally. The currently understood model of pathogenesis consists of a ‘multiple hit’ hypothesis in which environmental and genetic factors contribute to hepatic inflammation and injury.

AIM

To examine the genetic expression of NAFLD and non-alcoholic steatohepatitis (NASH) tissue samples to identify common pathways that contribute to NAFLD and NASH pathogenesis.

METHODS

We employed the Search Tag Analyze Resource for Gene Expression Omnibus platform to search the The National Center for Biotechnology Information Gene Expression Omnibus to elucidate NAFLD and NASH pathology. For NAFLD, we conducted meta-analysis of data from 58 NAFLD liver biopsies and 60 healthy liver biopsies; for NASH, we analyzed 187 NASH liver biopsies and 154 healthy liver biopsies.

RESULTS

Our results from the NAFLD analysis reinforce the role of altered metabolism, inflammation, and cell survival in pathogenesis and support recently described contributors to disease activity, such as altered androgen and long non-coding RNA activity. The top upstream regulator was found to be sterol regulatory element binding transcription factor 1 (SREBF1), a transcription factor involved in lipid homeostasis. Downstream of SREBF1, we observed upregulation in CXCL10, HMGCR, HMGCS1, fatty acid binding protein 5, paternally expressed imprinted gene 10, and downregulation of sex hormone-binding globulin and insulin-like growth factor 1. These molecular changes reflect low-grade inflammation secondary to accumulation of fatty acids in the liver. Our results from the NASH analysis emphasized the role of cholesterol in pathogenesis. Top canonical pathways, disease networks, and disease functions were related to cholesterol synthesis, lipid metabolism, adipogenesis, and metabolic disease. Top upstream regulators included pro-inflammatory cytokines tumor necrosis factor and IL1B, PDGF BB, and beta-estradiol. Inhibition of beta-estradiol was shown to be related to derangement of several cellular downstream processes including metabolism, extracellular matrix deposition, and tumor suppression. Lastly, we found riciribine (an AKT inhibitor) and ZSTK-474 (a PI3K inhibitor) as potential drugs that targeted the differential gene expression in our dataset.

CONCLUSION

In this study we describe several molecular processes that may correlate with NAFLD disease and progression. We also identified ricirbine and ZSTK-474 as potential therapy.

Advance of Serum Biomarkers and Combined Diagnostic Panels in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) affects approximately 25-30% population worldwide, which progresses from simple steatosis to nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and hepatocellular carcinoma, and has complications such as cardiovascular events. Liver biopsy is still the gold standard for the diagnosis of NAFLD, with some limitations, such as invasive, sampling deviation, and empirical judgment. Therefore, it is urgent to develop noninvasive diagnostic biomarkers. Currently, a large number of NAFLD-related serum biomarkers have been identified, including apoptosis, inflammation, fibrosis, adipokines, hepatokines, and omics biomarkers, which could effectively diagnose NASH and exclude patients with progressive fibrosis. We summarized serum biomarkers and combined diagnostic panels of NAFLD, to provide some guidance for the noninvasive diagnosis and further clinical studies.

Protective Effects and Mechanisms of Yinchen Linggui Zhugan Decoction in HFD-Induced Nonalcoholic Fatty Liver Disease Rats Based on Network Pharmacology and Experimental Verification

Nonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease, characterized by excessive accumulation of hepatocyte fat. However, there is no exact and effective pharmacotherapy for NAFLD. Yinchen linggui zhugan decoction (YLZD) has been widely used to treat NAFLD. Nevertheless, its pharmacological and molecular mechanisms have not been clearly elucidated. This study was carried out to investigate the active components of YLZD and explore its potential mechanisms for treating NAFLD by network pharmacology and experimental verification. The results showed that a total of 120 active components of YLZD and 365 targets were retrieved through databases, and the main active ingredients of YLZD consisted of chlorogenic acid, emodin, aloe-emodin, rhein, and geniposide. KEGG enrichment analysis revealed fundamental roles of TNF, PI3K/AKT, HIF-1α, and insulin resistance signaling pathways in the treatment of NAFLD by YLZD. Moreover, our experimental verification results showed that YLZD improved the liver pathological and cholesterol level, and reduced the expressions of TNF-α, IL-1β, IL-6, NF-κB, CCL2, and CXCL10 in NAFLD rats, which all belonged to TNF signaling pathway. The molecular docking confirmed the correlation between the four core components (chlorogenic acid, emodin, rhein, and geniposide) and key factors (TNF-α, IL-6, and NF-κB) in TNF signaling pathway. In conclusion, the present study systematically clarified the protective mechanisms of YLZD against NAFLD through targeting the TNF signaling pathway, and provided new ideas for the drug research of this disease.

Hepatoprotective effects of gemigliptin and empagliflozin in a murine model of diet-induced non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) includes a broad spectrum of liver diseases characterized by steatosis, inflammation, and fibrosis. This study aimed to investigate the potential of dipeptidyl peptidase-4 inhibitors and sodium-glucose cotransporter 2 inhibitors in alleviating the progression of NAFLD. The NAFLD model was generated by feeding male C57BL/6J mice a choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD) for 7 weeks. After 2 weeks of CDAHFD feeding, the NAFLD model mice were assigned to four groups, namely (ⅰ) VEHICLE, (ⅱ) gemigliptin (GEMI), (ⅲ) empagliflozin (EMPA), and (ⅳ) GEMI + EMPA. For the next 5 weeks, mice received the vehicle or the drug based upon the group to which they belonged. Thereafter, the triglyceride concentration, extent of fibrosis, and the expression of genes encoding inflammatory cytokines, chemokines, and antioxidant enzymes were analyzed in the livers of mice. The NAFLD activity score and hepatic fibrosis grade were assessed via hematoxylin and eosin and Sirius Red staining of the liver tissue samples. All mice belonging to the GEMI, EMPA, and GEMI + EMPA groups showed improvements in the accumulation of liver triglycerides and the expression of inflammatory cytokines and chemokines. Additionally, the oxidative stress was reduced due to inhibition of the c-Jun N-terminal kinase pathway and upregulation of the antioxidant enzymes. Furthermore, in these three groups, the galectin-3 and interleukin 33-induced activity of tumor necrosis factor-α was inhibited, thereby preventing the progression of liver fibrosis. These findings suggest that the GEMI, EMPA, and GEMI + EMPA treatments ameliorate hepatic steatosis, inflammation, oxidative stress, and fibrosis in CDAHFD-induced NAFLD mouse models.

Crucial role of T cells in NAFLD-related disease: A review and prospect

Nonalcoholic fatty liver disease (NAFLD) includes a series of hepatic manifestations, starting with liver steatosis and potentially evolving towards nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis or even hepatocellular carcinoma (HCC). Its incidence is increasing worldwide. Several factors including metabolic dysfunction, oxidative stress, lipotoxicity contribute to the liver inflammation. Several immune cell-mediated inflammatory processes are involved in NAFLD in which T cells play a crucial part in the progression of the disease. In this review, we focus on the role of different subsets of both conventional and unconventional T cells in pathogenesis of NAFLD. Factors regarding inflammation and potential therapeutic approaches targeting immune cells in NASH are also discussed.

Sulforaphane Attenuates Nonalcoholic Fatty Liver Disease by Inhibiting Hepatic Steatosis and Apoptosis

Nonalcoholic fatty liver disease (NAFLD) is characterized by lipotoxicity and ectopic lipid deposition within hepatocytes. Sulforaphane (SFA), an active compound used for inhibiting tumors, was found to have the potency to improve lipid metabolism. However, its molecular mechanisms on ameliorating NAFLD are still incompletely understood. This research evaluated if SFA could inhibit hepatic steatosis and apoptosis. The effects of SFA on cell viability, lipid accumulation, triglyceride (TG) contents, apoptosis, ceramide contents, and reactive oxygen species (ROS) levels were analyzed in palmitic acid (PA)-treated HepG2 cells and high-fat diet (HFD)-fed mice. The related molecular mechanisms were further explored in hepatocytes. The results showed SFA alleviated lipid accumulation and regulated AMPK/SREBP1c/FAS signaling pathway in PA-stressed HepG2 cells. In addition, SFA alleviated PA-mediated apoptosis, downregulated the expressions of cleaved caspase 3, as well as reduced ceramide contents and ROS levels. Moreover, SFA treatment reduced HFD-induced body weight gain, alleviated insulin resistance, decreased serum TG, total cholesterol (TC), and alanine aminotransferase (ALT) levels, and prevented lipid deposition and apoptosis in the liver. This study showed SFA suppressed lipid deposition and apoptosis both in vitro and in vivo, indicating that SFA may be a potential candidate for preventing and treating NAFLD.

Human Genetics to Identify Therapeutic Targets for NAFLD: Challenges and Opportunities

Non-alcoholic fatty liver disease (NAFLD) is a continuous progression of pathophysiologic stages that is challenging to diagnose due to its inherent heterogeneity and poor standardization across a wide variety of diagnostic measures. NAFLD is heritable, and several loci have been robustly associated with various stages of disease. In the past few years, larger genetic association studies using new methodology have identified novel genes associated with NAFLD, some of which have shown therapeutic promise. This mini-review provides an overview of the heterogeneity in NAFLD phenotypes and diagnostic methods, discusses genetic associations in relation to the specific stages for which they were identified, and offers a perspective on the design of future genetic mapping studies to accelerate therapeutic target identification.

TA allele of rs2070673 in the CYP2E1 gene is associated with lobular inflammation and nonalcoholic steatohepatitis in patients with biopsy-proven nonalcoholic fatty liver disease

BACKGROUND AND AIM

Cytochrome P450 2E1 (CYP2E1) plays a role in lipid metabolism, and by increasing hepatic oxidative stress and inflammation, the upregulation of CYP2E1 is involved in development of nonalcoholic steatohepatitis (NASH). We aimed to explore the relationship between CYP2E1-333A>T (rs2070673) and the histological severity of nonalcoholic fatty liver disease (NAFLD).

METHODS

We studied 438 patients with biopsy-proven NAFLD. NASH was defined as NAFLD Activity Score ≥ 5 with existence of steatosis, ballooning, and lobular inflammation. CYP2E1-333A>T (rs2070673) was genotyped by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Serum cytokines related to inflammation were measured by the Bio-plex 200 system to investigate possible mediating factors involved in the process.

RESULTS

The TA genotype of rs2070673 had a higher prevalence of moderate/severe lobular inflammation (27.6% vs 20.3% vs 13.3%, P < 0.01) and NASH (55.7% vs 42.4% vs 40.5%, P < 0.01) compared with the AA and TT genotypes, respectively. In multivariable regression modeling, the heterozygote state TA was associated with moderate/severe lobular inflammation (adjusted odds ratio: 2.31, 95% confidence interval 1.41-3.78, P < 0.01) or NASH (adjusted odds ratio: 1.82, 95% confidence interval 1.22-2.69, P < 0.01), independently of age, sex, common metabolic risk factors, and presence of liver fibrosis. Compared with no-NASH, NASH patients had significantly higher levels of serum interleukin-1 receptor antagonist, interleukin-18, and interferon-inducible protein-10 (IP-10), whereas only IP-10 was increased with the rs2070673 TA variant (P = 0.01). Mediation analysis showed that IP-10 was responsible for ~60% of the association between the rs2070672 and NASH.

CONCLUSIONS

The TA allele of rs2070673 is strongly associated with lobular inflammation and NASH, and this effect appears to be largely mediated by serum IP-10 levels.

The role of Th17 cells in viral infections

The present review provides an overview of recent advances regarding the function of Th17 cells and their produced cytokines in the progression of viral diseases. Viral infections alone do not lead to virus-induced malignancies, as both genetic and host safety factors are also involved in the occurrence of malignancies. Acquired immune responses, through the differentiation of Th17 cells, form the novel components of the Th17 cell pathway when reacting with viral infections all the way from the beginning to its final stages. As a result, instead of inducing the right immune responses, these events lead to the suppression of the immune system. In fact, the responses from Th17 cells during persistent viral infections causes chronic inflammation through the production of IL-17 and other cytokines which provide a favorable environment for tumor growth and its development. Additionally, during the past decade, these cells have been understood to be involved in tumor progression and metastasis. However, further research is required to understand Th17 cells' immune mechanisms in the vast variety of viral diseases. This review aims to determine the roles and effects of the immune system, especially Th17 cells, in the progression of viral diseases; which can be highly beneficial for the diagnosis and treatment of these infections.

Chemokines in Non-alcoholic Fatty Liver Disease: A Systematic Review and Network Meta-Analysis

Background: Previous results on the relationship between non-alcoholic fatty liver disease (NAFLD) and chemokine concentrations were inconsistent. The purpose of this network meta-analysis was to evaluate the link between chemokine system and NAFLD.

Methods: Relevant data, published not later than June 31, 2019, were searched in the databases of PubMed, Embase, Cochrane Library, and Web of Science. A network meta-analysis was used to rank the chemokines by surface under the cumulative ranking (SUCRA) probabilities. In addition, standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated as group differences in the chemokine concentrations.

Results: The search in the databases identified 46 relevant studies that investigated the relationship between 15 different chemokines and NAFLD using 4,753 patients and 4,059 controls. Results from the network meta-analysis showed that the concentrations of CCL2 and CXCL8 in the non-alcoholic fatty liver (NAFL) group was significantly higher than that in the control group (SMDs of 1.51 and 1.95, respectively), and the concentrations of CCL3, CCL4, CCL20, CXCL8, and CXCL10 in the non-alcoholic steatohepatitis (NASH) group was significantly higher than that in the control group (SMDs of 0.90, 2.05, 2.16, 0.91, and 1.46, respectively). SUCRA probabilities showed that CXCL8 had the highest rank in NAFL for all chemokines and CCL20 had the highest rank in NASH for all chemokines.

Conclusion: Elevated concentrations of CCL2, CCL4, CCL20, CXCL8, and CXCL10 may be associated with NAFL or NASH. In this regard, more population-based studies are needed to ascertain this hypothesis.

Systematic Review Registration: PROSPERO: CRD42020139373.

Discovery of plasma biomarkers for predicting the severity of coronary artery atherosclerosis by quantitative proteomics

INTRODUCTION

Cardiovascular disease (CVD) in patients with diabetes is the leading cause of death. Finding early biomarkers for detecting asymptomatic patients with CVD can improve survival. Recently, plasma proteomics-targeted selected reaction monitoring/multiple reaction monitoring analyses (MRM)-has emerged as highly specific and sensitive tools compared with classic ELISA methods. The objective was to identify differentially regulated proteins according to the severity of the coronary artery atherosclerosis.

RESEARCH DESIGN AND METHODS

A discovery cohort, a verification cohort and a validation cohort consisted of 18, 53, and 228 subjects, respectively. The grade of coronary artery stenosis was defined as a percentage of luminal stenosis of the major coronary arteries. Participants were divided into six groups, depending on the presence of diabetes and the grade of coronary artery stenosis. Two mass spectrometric approaches were employed: (1) conventional shotgun liquid chromatography tandem mass spectrometry for a discovery and (2) quantitative MRM for verification and validation. An analysis of the covariance was used to examine the biomarkers' predictivity beyond conventional cardiovascular risks.

RESULTS

A total of 1349 different proteins were identified from a discovery cohort. We selected 52 proteins based on the tandem mass tag quantitative analysis then summarized as follows: chemokine (C-X-C motif) ligand 7 (CXCL7), apolipoprotein C-II (APOC2), human lipopolysaccharide-binding protein (LBP) and dedicator of cytokinesis 2 (DOCK2) in diabetes; CXCL7, APOC2, LBP, complement 4A (C4A), vitamin D-binding protein (VTDB) and laminin β1 subunit in non-diabetes. Analysis of covariance showed that APOC2, DOCK2, CXCL7 and VTDB were upregulated and C4A was downregulated in patients with diabetes showing severe coronary artery stenosis. LBP and VTDB were downregulated in patients without diabetes, showing severe coronary artery stenosis.

CONCLUSION

We identified significant associations between circulating APOC2, C4A, CXCL7, DOCK2, LBP and VTDB levels and the degree of coronary artery stenosis using the MRM technique.

Using evasins to target the chemokine network in inflammation

Inflammation, is driven by a network comprising cytokines, chemokines, their target receptors and leukocytes, and is a major pathologic mechanism that adversely affects organ function in diverse human diseases. Despite being supported by substantial target validation, no successful anti-chemokine therapeutic to treat inflammatory disease has yet been developed. This is in part because of the robustness of the chemokine network, which emerges from a large total chemokine load in disease, promiscuous expression of receptors on leukocytes, promiscuous and synergistic interactions between chemokines and receptors, and feedforward loops created by secretion of chemokines by leukocytes themselves. Many parasites, including viruses, helminths and ticks, evade the chemokine network by producing proteins that bind promiscuously to chemokines or their receptors. Evasins - three small glycoproteins identified in the saliva of the brown dog tick - bind multiple chemokines, and are active in several animal models of inflammatory disease. Over 50 evasin homologs have recently been identified from diverse tick species. Characterization of the chemokine binding patterns of evasins show that several have anti-chemokine activities that extend substantially beyond those previously described. These studies indicate that evasins function at the site of the tick bite by reducing total chemokine load. This not only reduces chemokine signaling to receptors, but also interrupts feedforward loops, thus disabling the chemokine network. Taking the lead from nature, a goal for the development of new anti-chemokine therapeutics would be to reduce the total chemokine load in disease. This could be achieved by administering appropriate evasin combinations or by smaller peptides that mimic evasin action.

New insights and therapeutic implication of gut microbiota in non-alcoholic fatty liver disease and its associated liver cancer

The gastrointestinal tract represents one of the largest interfaces between the host and environmental factors. It contains a vast and complex community of microbes, forming what is collectively known as the microbiota. This gut microbiota plays a pivotal role in the maintenance of health, and 'dysbiosis' of the gut microbiota, commonly considered as perturbation of microbiota diversity and composition, has been associated with intestinal and extra-intestinal diseases, including non-alcoholic fatty liver disease (NAFLD) and its associated hepatocellular carcinoma (NAFLD-HCC). In this review, we highlight microbiota dysbiosis and the microbiota-host interactions that link to the pathogenesis of NAFLD and NAFLD-HCC. We discuss the potential therapeutic implications of the gut microbiota in the progression of NAFLD-HCC.

Systemic inflammation contributes to impairment of quality of life in chronic pancreatitis

Chronic pancreatitis (CP) is a fibrotic disorder of the pancreas leading to clinical sequelae like pain and an excess of comorbidity including cardiovascular disease and cancers. The aim of this study was to determine the relationship between systemic inflammation and quality of life in patients with CP. Patients were prospectively recruited and underwent a quality of life assessment (EORTC QLQ-C30 and PAN 28). The serum inflammatory profile was assessed using an MSD 30-plex array. The relationship between clinical variables, inflammatory cytokines and quality of life was determined by a GLM-MANOVA and the individual impact of significant variables evaluated by a second ANOVA. In total, 211 patients with a median age of 53 years were recruited across 5 European centres. Gender, age, nicotine and alcohol abuse were clinical variables associated with altered quality of life. Systemic inflammation with high levels of pro-inflammatory cytokines (Eotaxin, IL-1β, IL-7, IL-8, IL-12/IL-23p40, IL-12p70, IL-13, IL-16, IP-10, MCP-1, MCP-4, MDC, MIP-1a, TARC, TNFß) was associated with diminished quality of life in general and specific domains including pain, physical and cognitive functioning. As conclusion, CP is associated with a systemic inflammatory response that has a negative impact on quality of life and accelerates aging.

The role of hepatic macrophages in nonalcoholic fatty liver disease and nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is becoming common chronic liver disease because of the increasing global prevalence of obesity and consequently Nonalcoholic fatty liver disease (NAFLD). However, the mechanism for progression of NAFLD to NASH and then cirrhosis is not completely understood, yet. The triggering of these hepatic diseases is thought from hepatocyte injury caused by over-accumulated lipid toxicity. Injured hepatocytes release damage-associated molecular patterns (DAMPs), which can stimulate the Kupffer cells (KCs), liver-resident macrophages, to release pro-inflammatory cytokines and chemokines, and recruit monocyte-derived macrophages (MDMs). The increased activation of KCs and recruitment of MDMs accelerate the progression of NAFLD to NASH and cirrhosis. Therefore, characterization for activation of hepatic macrophages, both KCs and MDMs, is a baseline to figure out the progression of hepatic diseases. The purpose of this review is to discuss the current understanding of mechanisms of NAFLD and NASH, mainly focusing on characterization and function of hepatic macrophages and suggests the regulators of hepatic macrophages as the therapeutic target in hepatic diseases.

Function and therapeutic advances of chemokine and its receptor in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) represents a spectrum of hepatic pathology, ranging from simple accumulation of fat in its most benign form, steatohepatitis, to cirrhosis in its most advanced form. The prevalence of NAFLD is 20-30% in adults, and 10-20% of patients with NAFLD progress to nonalcoholic steatohepatitis (NASH) which is predicted to be the leading cause of liver transplantation over the next 10 years. Therefore, it is essential to explore effective diagnostic and treatment strategies for NAFLD patients. Chemokines are a family of small and highly conserved proteins (molecular weight ranging from 8 to 12 kDa) involved in regulating the migration and activities of hepatocytes, Kupffer cells (KCs), hepatic stellate cells (HSCs), endothelial cells and circulating immune cells. Accumulating data show that chemokine and its receptor act vital roles in the pathogenesis of NAFLD. Herein, we summarize the involvement of the chemokine and its receptor in the pathogenesis of NAFLD and explore the novel pharmacotherapeutic avenues for patients with NAFLD.

BET Inhibition Improves NASH and Liver Fibrosis

Non-alcoholic fatty liver disease (NAFLD) is a leading form of chronic liver disease with large unmet need. Non-alcoholic steatohepatitis (NASH), a progressive variant of NAFLD, can lead to fibrosis, cirrhosis, and hepatocellular carcinoma. To identify potential new therapeutics for NASH, we used a computational approach based on Connectivity Map (CMAP) analysis, which pointed us to bromodomain and extra-terminal motif (BET) inhibitors for treating NASH. To experimentally validate this hypothesis, we tested a small-molecule inhibitor of the BET family of proteins, GSK1210151A (I-BET151), in the STAM mouse NASH model at two different dosing timepoints (onset of NASH and progression to fibrosis). I-BET151 decreased the non-alcoholic fatty liver disease activity score (NAS), a clinical endpoint for assessing the severity of NASH, as well as progression of liver fibrosis and interferon-γ expression. Transcriptional characterization of these mice through RNA-sequencing was consistent with predictions from the CMAP analysis of a human NASH signature and pointed to alterations in molecular mechanisms related to interferon signaling and cholesterol biosynthesis, as well as reversal of gene expression patterns linked to fibrotic markers. Altogether, these results suggest that inhibition of BET proteins may present a novel therapeutic opportunity in the treatment of NASH and liver fibrosis.

Chemokines and Chemokine Receptors in the Development of NAFLD

Chemokines are chemo-attractants for leukocyte trafficking, growth, and activation in injured and inflammatory tissues. The chemokine system is comprised of 50 chemokine ligands and 20 cognate chemokine receptors. In the context of liver diseases, leukocytes, hepatocytes, hepatic stellate cells, endothelial cells, and vascular smooth muscle cells are capable of producing chemokines. Chemokine receptors are typically expressed in various leukocyte subsets. Given that inflammation is a critical factor for the transition from simple steatosis to non-alcoholic steatohepatitis (NASH), and fibrosis, the chemokine system may play a prominent role in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Indeed, accumulating evidence shows elevated expression of chemokines and their receptors in the livers of obese patients with advanced steatosis and NASH. This chapter will discuss the underlying molecular mechanisms and the therapeutic potential of the chemokine systems in the pathogenesis of NAFLD. Among chemokines, we will highlight CCL2, CCL5, CXCL8-10, CX3CL1, and CXCL16 as pivotal mediators in the development of steatosis, NASH, and fibrosis.

Resveratrol alleviates FFA and CCl4 induced apoptosis in HepG2 cells via restoring endoplasmic reticulum stress

Cell apoptosis often induces inflammation and injury in the liver, with endoplasmic reticulum (ER) stress as the most possible reason. Resveratrol (RSV) has been shown to prevent hepatic steatosis and alleviate apoptosis, however, the exact mechanisms underlying the effects still need to be explored. Here we co-cultured HepG2 cells with free fatty acid (FFA) solution (oleic acid: palmitic acid = 2:1) and then exposed to a carbon tetrachloride (CCl4) solution to induce apoptosis. To evaluate the therapeutic effects, RSV (2.5 μM, 5 μM, 10 μM) was added to the cells. Results showed that HepG2 cells co-cultured with FFA exhibited lipid infiltration and were susceptible to apoptosis upon exposure to the CCl4 solution. The expression of molecules related to apoptosis (Caspases, Bcl-2/Bax) and ER stress (GRP78, IRE1, ATF6, PERK, et al.) was all significantly decreased upon RSV treatment. We further inhibited GRP78 by siRNA, results showed that the anti-apoptotic effect of RSV still maintained under GRP78 siRNA condition. Our data demonstrated that lipid accumulated HepG2 cells were susceptible to injury, and RSV could improve apoptosis in FFA and CCl4 stressed cells, which partially via restoring ER function.

Immunity and Fibrogenesis: The Role of Th17/IL-17 Axis in HBV and HCV-induced Chronic Hepatitis and Progression to Cirrhosis

Cirrhosis is a common final pathway for most chronic liver diseases; representing an increasing burden worldwide and is associated with increased morbidity and mortality. Current evidence has shown that, after an initial injury, the immune response has a significant participation in the ongoing damage, and progression from chronic viral hepatitis (CVH) to cirrhosis, driving the activation and maintenance of main fibrogenic pathways. Among immune deregulations, those related to the subtype 17 of T helper lymphocytes (Th17)/interleukin-17 (IL-17) axis have been recognized as key immunopathological and prognostic elements in patients with CVH. The Th17/IL-17 axis has been found involved in several points of fibrogenesis chain from the activation of stellate cells, increased expression of profibrotic factors as TGF-β, promotion of the myofibroblastic or epithelial–mesenchymal transition, stimulation of the synthesis of collagen, and induction of imbalance between matrix metalloproteinases and tissue inhibitors of metalloproteinases (TIMPs). It also promotes the recruitment of inflammatory cells and increases the expression of proinflammatory cytokines such as IL-6 and IL-23. So, the Th17/IL-17 axis is simultaneously the fuel and the flame of a sustained proinflammatory and profibrotic environment. This work aims to present the immunopathologic and prognostic role of the Th17/IL-17 axis and related pathways in fibrogenesis and progression to cirrhosis in patients with liver disease due to hepatitis B virus (HBV) and hepatitis C virus (HCV).

C-X-C Motif Chemokine 10 Impairs Autophagy and Autolysosome Formation in Non-alcoholic Steatohepatitis

C-X-C motif chemokine 10 (CXCL10) is a crucial pro-inflammatory factor in chronic hepatitis. Autophagy dysregulation is known to contribute to hepatic inflammatory injury. Hence, we investigated the regulatory effect of CXCL10 on the autophagosome-lysosome system during non-alcoholic fatty liver disease (NAFLD) development. The effect of CXCL10 ablation by neutralizing monoclonal antibody (mAb) or genetic knockout on autophagic flux was evaluated in cultured hepatocytes and animal models of NAFLD. Results demonstrated that CXCL10 ablation protected against hepatocyte injury in vitro and steatohepatitis development in mice. Autophagic flux impairment was rectified by CXCL10 inhibition using anti-CXCL10 mAb in AML-12 and HepG2 liver cell lines and primary hepatocytes as evidenced by the attenuated accumulation of p62/SQSTM1 and LC3-II proteins and increased autophagic protein degradation. Impaired autophagic flux was significantly restored by CXCL10 knockout or anti-CXCL10 mAb in mice. Bafilomycin A1, an inhibitor of autolysosome formation, abolished the rectifying effect of anti-CXCL10 mAb or CXCL10 knockdown in AML-12 and primary hepatocytes, indicating CXCL10 impaired late-stage autophagy in NAFLD. Anti-CXCL10 mAb treatment also increased the fusion of LC3-positive autophagosomes with lysosomes in HepG2 cells challenged with palmitic acid, suggesting that CXCL10 ablation restored autolysosome formation. Consistently, the number of autolysosomes was significantly increased by CXCL10 knockout in mice as shown by electron microscopy. In conclusion, upregulated CXCL10 in steatohepatitis impairs autophagic flux by reducing autolysosome formation, thereby inhibiting autophagic protein degradation and the accumulation of ubiquitinated proteins, leading to the development of steatohepatitis.