Hepatic CD4 Research Articles

PDIA3 epitope-driven immune autoreactivity contributes to hepatic damage in type 2 diabetes.

A diet rich in saturated fat and carbohydrates causes low-grade chronic inflammation in several organs, including the liver, ultimately driving nonalcoholic steatohepatitis. In this setting, environment-driven lipotoxicity and glucotoxicity induce liver damage, which promotes dendritic cell activation and generates a major histocompatibility complex class II (MHC-II) immunopeptidome enriched with peptides derived from proteins involved in cellular metabolism, oxidative phosphorylation, and the stress responses. Here, we demonstrated that lipotoxicity and glucotoxicity, as driven by a high-fat and high-fructose (HFHF) diet, promoted MHC-II presentation of nested T and B cell epitopes from protein disulfide isomerase family A member 3 (PDIA3), which is involved in immunogenic cell death. Increased MHC-II presentation of PDIA3 peptides was associated with antigen-specific proliferation of hepatic CD4+ immune infiltrates and isotype switch of anti-PDIA3 antibodies from IgM to IgG3, indicative of cellular and humoral PDIA3 autoreactivity. Passive transfer of PDIA3-specific T cells or PDIA3-specific antibodies also exacerbated hepatocyte death, as determined by increased hepatic transaminases detected in the sera of mice subjected to an HFHF but not control diet. Increased humoral responses to PDIA3 were also observed in patients with chronic inflammatory liver conditions, including autoimmune hepatitis, primary biliary cholangitis, and type 2 diabetes. Together, our data indicated that metabolic insults caused by an HFHF diet elicited liver damage and promoted pathogenic immune autoreactivity driven by T and B cell PDIA3 epitopes.

From the Editor’s Desk…

From the Editor’s Desk…

MiR-146a Maintains Immune Tolerance of Kupffer Cells and Facilitates Hepatitis B Virus Persistence in Mice.

Kupffer cells (KCs), the largest tissue-resident macrophage population in the body, play a central role in maintaining a delicate balance between immune tolerance and immunity in the liver. However, the underlying molecular mechanism remains elusive. In this study, we show that KCs express high levels of miR-146a, which is under control of the PU.1 transcription factor. miR-146a deficiency promoted KCs differentiation toward a proinflammatory phenotype; conversely, miR-146a overexpression suppressed this phenotypic differentiation. We found that hepatitis B virus (HBV) persistence or HBV surface Ag treatment significantly upregulated miR-146a expression and thereby impaired polarization of KCs toward a proinflammatory phenotype. Furthermore, in an HBV carrier mouse model, KCs depletion by clodronate liposomes dramatically promoted HBV clearance and enhanced an HBV-specific hepatic CD8+ T cell and CD4+ T cell response. Consistent with this finding, miR-146a knockout mice cleared HBV faster and elicited a stronger adaptive antiviral immunity than wild-type mice. In vivo IL-12 blockade promoted HBV persistence and tempered the HBV-specific CTL response in the liver of miR-146a knockout mice. Taken together, our results identified miR-146a as a critical intrinsic regulator of an immunosuppressive phenotype in KCs under inflammatory stimuli, which may be beneficial in maintenance of liver homeostasis under physiological condition. Meanwhile, during HBV infection, miR-146a contributed to viral persistence by inhibiting KCs proinflammatory polarization, highlighting its potential as a therapeutic target in HBV infection.

Primary infection by E. multilocularis induces distinct patterns of hepatic crosstalk between natural killer T and regulatory T cells in mice

Abstract Objective The larval stage of the helminthic cestode Echinococcus multilocularis can inflict tumor-like hepatic lesions that cause the parasitic disease alveolar echinococcosis (AE) in humans. Recently, opportunistic properties of the disease have been proposed based on the increased incidence in immunocompromised patients as well as on mouse models, indicating that an appropriate adaptive immune response is required for the control of the disease. However, little is known about how the local hepatic immune responses modulate the infection with E. multilocularis. Methods In a mouse model of oral infection that mimics the normal infection route in human patients, the adaptive immune response in the liver was assessed using single cell RNA sequencing of isolated hepatic CD3+ T cells at different infection stages. Results Single-cell RNA sequencing revealed specific temporal changes of natural killer T (NKT) cells and regulatory T (Treg) cells, indicating that these two cell types expand in the early phase and are subsequently inhibited in the late phase of infection. Receptor-ligand complex analysis via CellPhoneDB, consistently revealed high number of interactions between Tregs and NKT mainly at day 10 post infection. Relevant interactions between NKT and Treg cells at early phases include regulation of cell adhesion molecules such as integrins and selectins and TNF-dependent signalling. Immune suppressing interactions that include the checkpoint inhibitors (PD-1 and PD-L1), purinergic (ENTPD1, ADORA2A) and TGF-beta signalling are down regulated at early time points. String analysis supported these findings. Conclusion The data indicate that early interactions between NKT and Tregs potentially promote the formation of hepatic lesions and later also contribute to immunological suppression of the resolution of parasite-induced pathology. The obtained data provide a fresh insight on the adaptive immune responses and local regulatory pathways at different infection stages of E. multilocularis in mice.

The gut microbiome contributes to splenomegaly and tissue inflammation in a murine model of primary biliary cholangitis

BackgroundSplenomegaly is not just a consequence of numerous chronic and acute conditions but may also contribute to their severity, due to the interaction of the spleen with the gut microbiome. This study aimed to explore the effect of the gut microbiome on splenomegaly.MethodsWe used p40−/−IL-2Rα−/− mice as a murine model of primary biliary cholangitis (PBC) as per our previous study. Splenomegaly was evaluated by spleen weight. Severity of liver inflammation was evaluated by hepatic mononuclear cell (MNCs) number and pathological score. Changes of immune cells in the spleen and liver were detected by flow cytometry. The effects of the gut microbiome on splenomegaly and liver inflammation were observed by combined antibiotic treatment in p40−/−IL-2Rα−/− mice.ResultsA proportion of p40−/−IL-2Rα−/− mice developed splenomegaly. The results revealed that liver mononuclear cells infiltration, histological scores of hepatic inflammation, and bile duct damage were positively correlated with the degree of splenomegaly. Hepatic CD4+ and CD8+ T cells numbers were significantly higher in mice with splenomegaly, and this was particularly observed in activated effector memory CD4+ T and CD8+ T cells. A proportion of some other immune cells including granulocytes, B, natural killer (NK), and CD8+ T effector memory cells were also altered in the enlarged spleen. More importantly, administration of quadruple antibiotics to deplete gut microbiota relieved the splenomegaly of p40−/−IL-2Rα−/− mice, significantly alleviated liver inflammation, and caused a significant reduction of liver and spleen T cell accumulation and activation; however, single antibiotics did not induce these changes.ConclusionsSplenomegaly was associated with more severe liver inflammation in our PBC murine model, and this effect was reversed by quadruple antibiotic treatment.

Type I Interferon remodels intrahepatocytic signaling to promote T cell dysfunction during liver stage Plasmodium infection

Abstract Malaria is caused by Plasmodium parasites and accounted for 627,000 deaths in 2021. Upon deposition into the dermis, Plasmodium parasites traffic to, infect, and develop within hepatocytes before egressing to cause symptomatic erythrocytic infection. We recently reported that liver stage Plasmodium replication induces type I Interferon (IFN-I) signaling that compromises anti-malaria T cells. We now show that this IFN-I-mediated, inferior T cell response is mostly limited to hepatic CD8 T cells and is characterized by diminished cytokine production, impaired homeostatic CD8 T cell survival, and the expression of receptors and transcription factors associated with T cell exhaustion. We set out to identify the cells and molecular events involved in the induction of T cell exhaustion during the transient and non-persistent liver stage Plasmodium infection and observed that infected mice lacking IFNAR expression solely on hepatocytes do not generate significant frequencies of exhausted T cells. Furthermore, transcriptomic analyses of hepatocytes isolated during infection indicate that IFN-I signaling coincides with a remodeling of the hepatocyte transcriptome such that antigen processing and presentation, chemokine transcripts and immunoregulatory receptors and soluble factors are upregulated. We hypothesize that IFN-I signaling reshapes the hepatocyte transcriptome to promote an immunosuppressive liver microenvironment that impairs anti-malaria T cells. Together, our studies represent the first description of a negative role for liver stage IFN-I signaling on anti-malaria adaptive immunity and may necessitate a paradigm shift in the rational design of efficacious anti-malaria whole parasite vaccines. Supported by 1U01AI42001

Sterile liver inflammation and T cell-intrinsic T-bet expression drive the formation of Tissue Resident Memory CD4 T cells that protect against systemic Salmonella infection

Abstract Infection with Salmonella enterica serovar Typhimurium (ST) can cause invasive Non-Typhoidal Salmonellosis (iNTS), a systemic disease which kills about 150,000 people annually. In a mouse model of systemic salmonellosis, hepatic tissue resident memory (TRM) CD4 T cells provided protection against subsequent infection. However, the signals required to generate these protective CD4 T cells remain poorly defined. To interrogate the process of hepatic CD4 TRM formation we developed a simple Salmonella-specific transfer system. ST-specific (SM1) TCR transgenic CD4 T cells were activated in vitro and adoptively transferred into C57BL/6 mice undergoing acetaminophen overdose. Sterile liver inflammation enhanced the formation of hepatic TRM SM1 T cells which expressed increased levels of T-bet compared to circulating memory cells. Subsequent mixed bone marrow chimera experiments substantiated the requirement for T-bet in hepatic TRM formation as T-bet-deficient CD4 T cells were deficient in resident memory. Bulk RNAseq analysis of hepatic CD4 TRMs uncovered a variety of cytokine and chemokine receptors that correlated with hepatic tissue residency. Using a combination of gene-deficiency and in vivo neutralization approaches, efforts are ongoing to uncover key components of sterile hepatic inflammation that drive CD4 TRM development. Understanding this process is critical to understanding the process of CD4 TRM development and will be foundational for the development of an effective vaccine against iNTS. Supported by NIAID R01AI139410, NIH T32 Animal Models of Infectious Diseases

Single-Cell Characterization of Hepatic CD8+ T Cells in a Murine Model of Primary Biliary Cholangitis.

Primary biliary cholangitis (PBC), an organ-specific autoimmune disease, is characterized by injury to small bile ducts, inflammatory cell infiltrates within the liver, progressive cholestasis, and in some cases, cirrhosis with unclear pathogenesis. We aimed to clarify the importance role of hepatic immunce cells in the pathogenesis of human and experimental PBC.The dominant-negative TGFβ receptor type II transgenic (dnTGFβRII) mice, a well-studied and established murine model of PBC were used to identify changes of immune cells, especially the pathogenic CD8+ T cells. The high-throughput single-cell RNA sequencing technology were applied and found functional heterogeneity among the hepatic CD8+ T cells subsets in dnTGFβRII mice. CD8+ T cells were confirmed the key cells leading to the pathogenesis of PBC in dnTGFβRII mice, and identified the terminally differentiated CD8αα T cells and CD8αβ T cell subsets in the liver of dnTGFβRII mice. While terminally differentiated CD8αα T cells have higher cytokine production ability and cytotoxicity, the terminally differentiated CD8αβ T cells retain their proliferative profile. Our work suggests that there are developmental and differentiated trajectories of pathogenic CD8+ T cell subsets in the pathogenesis of PBC. A further clarification of their roles would be helpful to our understanding of the pathogenesis of PBC and may potentially lead to identifying novel therapeutic modalities.

Dietary Inclusion of Seabuckthorn (Hippophae rhamnoides) Mitigates Foodborne Enteritis in Zebrafish Through the Gut-Liver Immune Axis.

To help prevent foodborne enteritis in aquaculture, several feed additives, such as herbal medicine, have been added to fish diets. Predictions of effective herb medicines for treating fish foodborne enteritis from key regulated DEGs (differentially expressed genes) in transcriptomic data can aid in the development of feed additives using the Traditional Chinese Medicine Integrated Database. Seabuckthorn has been assessed as a promising candidate for treating grass carp soybean-induced enteritis (SBMIE). In the present study, the SBMIE zebrafish model was used to assess seabuckthorn’s therapeutic or preventative effects. The results showed that intestinal and hepatic inflammation was reduced when seabuckthorn was added, either pathologically (improved intestinal villi morphology, less oil-drops) or growth-related (body fat deposition). Moreover, seabuckthorn may block the intestinal p53 signaling pathway, while activating the PPAR signaling pathway and fatty acid metabolism in the liver. 16S rRNA gene sequencing results also indicated a significant increase in OTU numbers and skewed overlapping with the fish meal group following the addition of seabuckthorn. Additionally, there were signs of altered gut microbiota taxa composition, particularly for reduced TM7, Sphingomonas, and Shigella, following the addition of seabuckthorn. Hindgut imaging of fluorescent immune cells in SBMIE larvae revealed the immune regulatory mechanisms at the cellular level. Seabuckthorn may significantly inhibit the inflammatory gathering of neutrophils, macrophages, and mature T cells, as well as cellular protrusions’ formation. On the other hand, in larvae, seabuckthorn inhibited the inflammatory aggregation of lck+ T cells but not immature lymphocytes, indicating that it affected intestinal adaptive immunity. Although seabuckthorn did not affect the distribution of intestinal CD4+ cells, the number of hepatic CD4+ cells were reduced in fish from the seabuckthorn supplementation group. Thus, the current data indicate that seabuckthorn may alleviate foodborne gut-liver symptoms by enhancing intestinal mucosal immunity and microbiota while simultaneously inhibiting hepatic adipose disposition, making it a potential additive for preventing fish foodborne gut-liver symptoms.

Effects of caloric restriction on the gut microbiome are linked with immune senescence

BackgroundCaloric restriction can delay the development of metabolic diseases ranging from insulin resistance to type 2 diabetes and is linked to both changes in the composition and metabolic function of the gut microbiota and immunological consequences. However, the interaction between dietary intake, the microbiome, and the immune system remains poorly described.ResultsWe transplanted the gut microbiota from an obese female before (AdLib) and after (CalRes) an 8-week very-low-calorie diet (800 kcal/day) into germ-free mice. We used 16S rRNA sequencing to evaluate taxa with differential abundance between the AdLib- and CalRes-microbiota recipients and single-cell multidimensional mass cytometry to define immune signatures in murine colon, liver, and spleen. Recipients of the CalRes sample exhibited overall higher alpha diversity and restructuring of the gut microbiota with decreased abundance of several microbial taxa (e.g., Clostridium ramosum, Hungatella hathewayi, Alistipi obesi). Transplantation of CalRes-microbiota into mice decreased their body fat accumulation and improved glucose tolerance compared to AdLib-microbiota recipients. Finally, the CalRes-associated microbiota reduced the levels of intestinal effector memory CD8+ T cells, intestinal memory B cells, and hepatic effector memory CD4+ and CD8+ T cells.ConclusionCaloric restriction shapes the gut microbiome which can improve metabolic health and may induce a shift towards the naïve T and B cell compartment and, thus, delay immune senescence. Understanding the role of the gut microbiome as mediator of beneficial effects of low calorie diets on inflammation and metabolism may enhance the development of new therapeutic treatment options for metabolic diseases.Trial registrationNCT01105143, “Effects of negative energy balance on muscle mass regulation,” registered 16 April 2010.5rgGJcWAo76KA7q12F4J9PVideo

The transcription factor Eomes promotes expression of inhibitory receptors on hepatic CD8+ T cells during HBV persistence.

Persistent infection with the hepatitis B virus (HBV) can aggravate the state of immune tolerance, inhibit the function of immune cells, and even lead to immune cell exhaustion in the liver microenvironment. The dysfunction of immune cells causes HBV to escape immune surveillance and eradication. Increasing evidence has revealed the molecular and cellular mechanisms of the induction of T-cell exhaustion during chronic viral persistence. However, the exact mechanisms of T cell exhaustion during chronic persistence of HBV infection are not fully understood. In this study, we analyzed the expression of inhibitory receptors and the exhausted status of liver T cells in a murine model with persistent HBV. We observed higher expression of the inhibitory receptors PD-1, LAG-3, and CD160 on liver CD8+ T cells accompanied by lower production of IFN-γ and TNF-α in HBV persistence mice. T cell-specific deficiency of the transcription factor Eomes significantly decreased the expression of the inhibitory receptors, restored the cytokine production of hepatic CD8+ T cells, and promoted HBV clearance. Similar phenomena were observed in peripheral blood CD8+ T cells from CHB patients. Mechanistically, Eomes not only directly promoted CD160 expression but also indirectly facilitated the coexpression of inhibitory receptors (PD-1, LAG-3, CD160) and T cell exhaustion by enhancing the transcription capacity of other key transcription factors (NFATc1, Blimp1, and FoxO1). These findings provide insight into the transcriptional regulation mechanisms of T cell exhaustion during chronic persistence of HBV and suggest novel therapeutic targets to reverse T cell exhaustion and eradicate HBV persistence.

CpG-C ODN M362 as an immunoadjuvant for HBV therapeutic vaccine reverses the systemic tolerance against HBV

Chronic Hepatitis B virus (CHB) infection is a global public health problem. Oligodeoxynucleotides (ODNs) containing class C unmethylated cytosine-guanine dinucleotide (CpG-C) motifs may provide potential adjuvants for the immunotherapeutic strategy against CHB, since CpG-C ODNs stimulate both B cell and dendritic cell (DC) activation. However, the efficacy of CpG-C ODN as an anti-HBV vaccine adjuvant remains unclear. In this study, we demonstrated that CpG M362 (CpG-C ODN) as an adjuvant in anti-HBV vaccine (cHBV-vaccine) successfully and safely eliminated the virus in HBV-carrier mice. The cHBV-vaccine enhanced DC maturation both in vivo and in vitro, overcame immune tolerance, and recovered exhausted T cells in HBV-carrier mice. Furthermore, the cHBV-vaccine elicited robust hepatic HBV-specific CD8+ and CD4+ T cell responses, with increased cellular proliferation and IFN-γ secretion. Additionally, the cHBV-vaccine invoked a long-lasting follicular CXCR5+ CD8+ T cell response following HBV re-challenge. Taken together, CpG M362 in combination with rHBVvac cleared persistent HBV and achieved long-term virological control, making it a promising candidate for treating CHB.

Malaria parasite liver stages

Malaria parasite liver stages

The human liver microenvironment shapes the homing and function of CD4+ T-cell populations

ObjectiveTissue-resident memory T cells (TRM) are vital immune sentinels that provide protective immunity. While hepatic CD8+ TRM have been well described, little is known about the location, phenotype and function...

Antigen-specific response of CD4+ T cells and hepatic lymph node cells to Fasciola hepatica-derived molecules at the early and late stage of the infection in sheep

The immunomodulatory capacity of F. hepatica antigens is probably one of the main reasons for the development of a driven non-protective Th2 immune response. In this study, we analysed the cellular response of hepatic lymph node cells and CD4+ T cells in terms of proliferative response, efficiency of antigen presentation and cytokine production, to F. hepatica-derived molecules, at early and late stages of the infection. Thirty-one sheep were allocated into five groups and were slaughtered at 16 dpi and 23 wpi. In order to analyse antigen-specific response, the following F. hepatica recombinant molecules were used: rFhCL1, rFhCL2, rFhCL3, rFhCB1, rFhCB2, rFhCB3, rFhStf-1, rFhStf-2, rFhStf-3 and rFhKT1. A cell proliferation assay using hepatic lymph node cells and an antigen presentation cell assay using CD4+ T cells were performed. At 16 dpi, all molecules but rFhStf-2 and rFhKT1 elicited a significant cell proliferative response on hepatic lymph node cells of infected animals. At both early and late stage of the infection, antigen presentation of rFhCB3 and rFhCL2 resulted in higher stimulation index of CD4+ T cells which was IL-2 mediated, although no statistically significant when compared to uninfected animals. Significant cytokine production (IL-4, IL-10 and IFN-γ) was conditioned by the antigen-specific cell stimulation. No CD4+ T cell exhaustion was detected in infected sheep at the chronic stage of the infection. This study addressed antigen-specific response to F. hepatica-derived molecules that are involved in key aspects of the parasite survival within the host.

The Clinical Significance of Hepatic CD69+ CD103+ CD8+ Resident-Memory T Cells in Autoimmune Hepatitis.

The diverse inflammatory response found in the liver of patients with autoimmune hepatitis (AIH) is well established, but identification of potentially pathogenic subpopulations has proven enigmatic. We report herein that CD69+ CD103+ CD8+ tissue-resident memory T cells (TRM ) are significantly increased in the liver of patients with AIH compared to chronic hepatitis B, NAFLD, and healthy control tissues. In addition, there was a significant statistical correlation between elevation of CD8+ TRM cells and AIH disease severity. Indeed, in patients with successful responses to immunosuppression, the frequencies of such hepatic CD8+ TRM cells decreased significantly. CD69+ CD8+ and CD69+ CD103+ CD8+ T cells, also known as CD8+ TRM cells, reflect tissue residency and are well known to provide intense immune antigenic responses. Hence, it was particularly interesting that patients with AIH also manifest an elevated expression of IL-15 and TGF-β on inflammatory cells, and extensive hepatic expression of E-cadherin; these factors likely contribute to the development and localization of CD8+ TRM cells. Based on these data and, in particular, the relationships between disease severity and CD8+ TRM cells, we studied the mechanisms involved with glucocorticoid (GC) modulation of CD8+ TRM cell expansion. Our data reflect that GCs in vitro inhibit the expansion of CD8+ TRM cells induced by IL-15 and TGF-β and with direct down-regulation of the nuclear factor Blimp1 of CD8+ TRM cells. Our data suggest that CD8+ TRM cells play a critical role in the pathogenesis of AIH, and GCs attenuate hepatic inflammation through direct inhibition of CD8+ TRM cell expansion.

Gut microbiome-host interactions in driving environmental pollutant trichloroethene-mediated autoimmunity

Trichloroethene (TCE), a widely used industrial solvent, is associated with the development of autoimmune diseases (ADs), including systemic lupus erythematosus and autoimmune hepatitis. Increasing evidence support a linkage between altered gut microbiome composition and the onset of ADs. However, it is not clear how gut microbiome contributes to TCE-mediated autoimmunity, and initial triggers for microbiome-host interactions leading to systemic autoimmune responses remain unknown. To achieve this, female MRL+/+ mice were treated with 0.5 mg/ml TCE for 52 weeks and fecal samples were subjected to 16S rRNA sequencing to determine the microbiome composition. TCE exposure resulted in distinct bacterial community revealed by β-diversity analysis. Notably, we observed reduction in Lactobacillaceae, Rikenellaceae and Bifidobacteriaceae families, and enrichment of Akkermansiaceae and Lachnospiraceae families after TCE exposure. We also observed significantly increased colonic oxidative stress and inflammatory markers (CD14 and IL-1β), and decreased tight junction proteins (ZO-2, occludin and claudin-3). These changes were associated with increases in serum antinuclear and anti-smooth muscle antibodies and cytokines (IL-6 and IL-12), together with increased PD1 + CD4+ T cells in TCE-exposed spleen and liver tissues. Importantly, fecal microbiota transplantation (FMT) using feces from TCE-treated mice to antibiotics-treated mice induced increased anti-dsDNA antibodies and hepatic CD4+ T cell infiltration in the recipient mice. Our studies thus delineate how imbalance in gut microbiome and mucosal redox status together with gut inflammatory response and permeability changes could be the key factors in contributing to TCE-mediated ADs. Furthermore, FMT studies provide a solid support to a causal role of microbiome in TCE-mediated autoimmunity.

MAPK regulates the immune responses in liver cirrhosis and hepatocellular carcinoma

Abstract Liver diseases causes approximately 2 million death per year worldwide. Aberrant apoptosis is associated with the progression of liver fibrosis and cirrhosis, even for hepatocellular carcinoma (HCC). HCC is one of major causes of cancer death worldwide due to high heterogeneity and recurrence. Immune scores could be used to link HCC disease-free survival and to identify several microenvironment-related genes. MAPK signaling plays an important role in liver fibrogenesis and HCC. ERK activation is associated with aggressive HCC, resulting in short overall survival. In this study, the immune responses of liver fibrosis and HCC mediated by ERK signaling were investigated. Both WT and Erk2 deficient mice were fed with choline-deficient diet to induce liver cirrhosis. Erk2 deficient livers have less degree of liver cirrhosis than WT livers. Our preliminary data suggested there was a significant increasement in the percentages of regulatory T cells in Erk2 deficient splenocytes. The percentages of follicular T cells were similar in WT and Erk2 deficient splenocytes. However, there was no significant differences in Erk2 deficient hepatic CD4 T cells for regulatory T cells and follicular T cells. In addition, Egr1 is one of ERK signaling downstream transcription factors. In HCC, there were about 10-fold differences in gene expression in the Egr1high and Egr1low group and the differential gene expression was identified. In hepatotoxicity, there was about more than 100 genes involved in HCC, 50~70 genes in liver cirrhosis, liver inflammation and liver necrosis/cell death. Therefore, MAPK signaling plays an important role in regulating the immune responses in the liver cirrhosis and HCC progression.

Hepatic Macrophage activation and the LPS pathway in patients with different degrees of severity and histopathological patterns of drug induced liver injury.

Inflammatory activation of hepatic macrophages plays a primary role in drug-induced liver injury (DILI). However, the exact mechanism underlying DILI remains unclear. A total of 328 DILI patients and 80 healthy individuals were prospectively enrolled in this study. The DILI patients were categorized into subgroups based on either disease severity or histopathological patterns. Plasma soluble CD163 (sCD163) and hepatic CD163 were examined to determine hepatic macrophage activation, and CD8, CD20, and MUM-1 were assessed to determine cellular immunity using immunohistochemistry. The lipopolysaccharide (LPS) pathway proteins [e.g. LPS, soluble CD14 (sCD14), and LPS-binding protein (LBP)] were measured using enzyme-linked immunosorbent assay. Plasma sCD163 levels were nine-fold higher in DILI patients than in healthy controls at the baseline, but significantly decreased at the 4-week follow-up visit after treatment. The numbers of hepatic macrophages, B cells, and plasma cells were significantly higher in the liver tissues from DILI patients than those from healthy controls. Furthermore, the baseline levels of LPS pathway proteins in the DILI patients were significantly higher than those in the controls. Notably, these proteins significantly decreased at the 4-week follow-up visit but remained significantly higher than the levels for the controls. Hepatic inflammation in DILI involves the activation of hepatic macrophages and cellular immunity, in which the LPS pathway likely plays a role, at least in part. As such, this study has improved our understanding of the pathological mechanisms for DILI and may facilitate the development of better treatments for patients with DILI.

NASH limits anti-tumour surveillance in immunotherapy-treated HCC

Hepatocellular carcinoma (HCC) can have viral or non-viral causes1–5. Non-alcoholic steatohepatitis (NASH) is an important driver of HCC. Immunotherapy has been approved for treating HCC, but biomarker-based stratification of patients for optimal response to therapy is an unmet need6,7. Here we report the progressive accumulation of exhausted, unconventionally activated CD8+PD1+ T cells in NASH-affected livers. In preclinical models of NASH-induced HCC, therapeutic immunotherapy targeted at programmed death-1 (PD1) expanded activated CD8+PD1+ T cells within tumours but did not lead to tumour regression, which indicates that tumour immune surveillance was impaired. When given prophylactically, anti-PD1 treatment led to an increase in the incidence of NASH–HCC and in the number and size of tumour nodules, which correlated with increased hepatic CD8+PD1+CXCR6+, TOX+, and TNF+ T cells. The increase in HCC triggered by anti-PD1 treatment was prevented by depletion of CD8+ T cells or TNF neutralization, suggesting that CD8+ T cells help to induce NASH–HCC, rather than invigorating or executing immune surveillance. We found similar phenotypic and functional profiles in hepatic CD8+PD1+ T cells from humans with NAFLD or NASH. A meta-analysis of three randomized phase III clinical trials that tested inhibitors of PDL1 (programmed death-ligand 1) or PD1 in more than 1,600 patients with advanced HCC revealed that immune therapy did not improve survival in patients with non-viral HCC. In two additional cohorts, patients with NASH-driven HCC who received anti-PD1 or anti-PDL1 treatment showed reduced overall survival compared to patients with other aetiologies. Collectively, these data show that non-viral HCC, and particularly NASH–HCC, might be less responsive to immunotherapy, probably owing to NASH-related aberrant T cell activation causing tissue damage that leads to impaired immune surveillance. Our data provide a rationale for stratification of patients with HCC according to underlying aetiology in studies of immunotherapy as a primary or adjuvant treatment.