Project description:The pathological progression of nonalcoholic fatty liver disease (NAFLD) is driven by multiple factors, and nonalcoholic steatohepatitis (NASH) represents its progressive form. In our previous studies, we found that bicyclol had beneficial effects on NAFLD/NASH. Here we aim to investigate the underlying molecular mechanisms of the bicyclol effect on NAFLD/NASH induced by high-fat diet (HFD) feeding. A mice model of NAFLD/NASH induced by HFD-feeding for 8 weeks was used. As a pretreatment, bicyclol (200 mg/kg) was given to mice by oral gavage twice daily. Hematoxylin and eosin (H&E) stains were processed to evaluate hepatic steatosis, and hepatic fibrous hyperplasia was assessed by Masson staining. Biochemistry analyses were used to measure serum aminotransferase, serum lipids, and lipids in liver tissues. Proteomics and bioinformatics analyses were performed to identify the signaling pathways and target proteins. The real-time RT-PCR and Western blot analyses were performed to verify the proteomics data. As a result, bicyclol had a markedly protective effect against NAFLD/NASH by suppressing the increase of serum aminotransferase, hepatic lipid accumulation and alleviating histopathological changes in liver tissues. Proteomics analyses showed that bicyclol remarkably restored major pathways related to immunological responses and metabolic processes altered by HFD feeding. Consistent with our previous results, bicyclol significantly inhibited inflammation and oxidative stress pathway related indexes (SAA1, GSTM1 and RDH11). Furthermore, the beneficial effects of bicyclol were closely associated with the signaling pathways of bile acid metabolism (NPC1, SLCOLA4 and UGT1A1), cytochrome P450-mediated metabolism (CYP2C54, CYP2C70 and CYP3A25), biological processes such as metal ion metabolism (Ceruloplasmin and Metallothionein-1), angiogenesis (ALDH1A1) and immunological responses (IFI204 and IFIT3). These findings suggested that bicyclol is a potential preventive agent for NAFLD/NASH by targeting multiple mechanisms in future clinical investigations.

Project description:Background & Aims: Overnutrition is one of the major causes of non-alcoholic fatty liver disease (NAFLD) and its advanced form non-alcoholic steatohepatitis (NASH). Besides the quantity of consumed calories, distinct dietary components are increasingly recognized as important contributor to the pathogenesis of NASH. We aimed to develop and characterize a hitherto missing murine model which resembles both the pathology and nutritional situation of NASH-patients in Western societies. Methods: We developed a NASH-inducing diet (ND) enriched with sucrose, cholesterol and a high concentration of fats rich in saturated fatty acids in a composition which mimics Western food. C57Bl6/N mice were fed with the ND or control chow for 12 weeks. Biochemical, real-time polymerase chain reaction, Western Blot and immunohistochemical analyses were performed to characterize systemic and hepatic changes induced by ND-feeding. Immunohistochemistry was used to assess c-Jun levels and activation in 110 human NAFLD and control liver specimens applying tissue micro array technology. Results: ND-fed mice showed significant body weight gain, impaired glucose tolerance, elevated fasting blood glucose levels as well as decreased adiponectin and increased leptin serum levels compared to control mice. In the liver, ND-feeding led to marked steatosis, enhanced cholesterol levels, distinct signs of oxidative stress, hepatocellular damage, inflammation, activation of hepatic stellate cells, and beginning fibrosis. Transcriptome-wide hepatic gene expression analysis comparing ND-fed mice and control mice indicated main alterations in lipid metabolism and inflammatory processes. Search for over-represented transcription factor target sites among the differentially expressed genes identified AP-1 as the most likely factor to cause the transcriptional changes in ND-livers. Combining differentially expressed gene and protein-protein interaction network analysis identified c-Jun (a component of the AP-1 complex) as hub in the largest connected deregulated sub-network in ND-livers. In accordance, ND-livers revealed c-Jun-phosphorylation and nuclear translocation. Moreover, hepatic c-Jun RNA and protein expression was enhanced in ND-fed compared to control mice. Also NAFLD-patients showed enhanced hepatic c-Jun levels, which correlated with inflammation, and notably, with the degree of hepatic steatosis. Conclusions: The new dietary mouse-model shows important pathological changes also found in human NASH and indicates c-jun/AP-1 activation as critical regulator of hepatic alterations. Abundance of c-jun in NAFLD likely facilitates development and progression of NASH, and thus, c-jun appears as attractive prognostic and therapeutic target of NAFLD progression. 14-weeks old male C57BL/6N mice were fed with either regular diet or a newly designed NASH-inducing diet for 12 weeks. Hepatic gene expression levels were measured thereafter.

Project description:Immunotherapy has opened hitherto unknown possibilities to treat cancer. Whereas some cancer types (e.g. melanoma) can be efficiently treated, others lack measurable positive effects (e.g. PDAC). Moreover, stratification of responders/non-responders is only possible in some cancer types (e.g. melanoma). Hepatocellular carcinoma (HCC) has a dismal prognosis, limited treatment options and survival benefit, and represents a potential cancer entity for successful immunotherapy. Here, we investigated NASH-triggered HCC in the context PD-1-targeted immunotherapy. Using flow cytometry, single cell RNA sequencing, immunohistochemistry and mass spectrometric analyses, we found a progressive increase of CD8+PD-1+ effector T-cells with a unique profile of exhaustion and activation markers rising with murine and human NASH severity. Notably, late-stage HCC treatment with PD-1-targeted immunotherapy enhanced hepatic carcinogenesis in mice. Dissecting potential mechanisms of action during tumor-initiation and -progression we analyzed the effects of PD-1-targeted immunotherapy at HCC initiation. PD-1-targeted immunotherapy induced a pro-tumorigenic environment, enhanced necro-inflammation and increased NAFLD-activation score (NAS), leading to increased liver cancer incidence, tumor number and nodule size. In contrast, anti-CD8 or anti-CD8/anti-NK1.1 treatment reduced NAS and abrogated the development of liver cancer, thus identifying CD8+PD-1+ T-cells as drivers of liver cancer in NASH-triggered HCC. Increased apoptotic signaling, STAT3 phosphorylation and hepatic proliferation were detected in intra-tumoral liver tissue upon PD-1-targeted immunotherapy. In line, PD-1-/- mice challenged with a NASH diet displayed early onset of hepatocarcinogenesis, corroborating the pro-tumorigenic role of absent or reduced PD-1. Mechanistically PD-1-targeted immunotherapy mainly affected hepatic abundance of CD8+PD-1+ T-cells, instead of altering the quality of Tox+CXCR6+ expressing CD8+PD-1+TNF+CD39+Gzmb+ T-cells found in NASH livers, leading to an aggressive, pro-tumorigenic liver environment. Single-cell mapping of human NASH-, borderline NASH- or unaffected livers corroborated our preclinical NASH results. Moreover, in human NASH livers a correlation of hepatic CD8+, PD-1+, TNF+ T-cells with fibrosis and NASH severity was observed. Accordingly, HCC patients with NASH etiology display a sharp increase in intra- and peri-tumoral CD8+ PD-1+ T-cells. In a cohort of 65 patients recruited across 6 centers in Germany and Austria, patients with NAFLD/NASH-driven HCC responded worse to PD-1-targeted immunotherapy by Nivolumab or Pembrolizumab compared to non-NAFLD patients. This resulted in significant reduced overall survival, in trends of faster disease progression and reduced progression free survival. Histological analysis of livers derived from HCC patients treated with PD-1-targeted immunotherapy displayed high levels of intra and peri-tumoral CD8+ PD-1+ T-cells and Ki67+ hepatocytes. Taken together, these data indicate that PD-1-targeted immunotherapy induces immune-related adverse effects in NAFLD/NASH-driven HCC through CD8+PD-1+ T-cells. Our data call for stratification of HCC patients subjected to PD-1-targeted immunotherapy, with NAFLD being a negative predictor.

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