Antigen-presenting cell function in the tolerogenic liver environment. Nat Rev Immunol. 2010;10:753-766. [PMID: 20972472 DOI: 10.1038/nri2858]

The Critical Role of Regulatory T Cells in Immune Tolerance and Rejection Following Liver Transplantation: Interactions With the Gut Microbiome

Liver transplantation (LT) is the ultimate treatment for patients with end-stage liver disease or early hepatocellular carcinoma. In the context of LT, because of the unique immunological characteristics of human liver allograft, 5%-20% of selected LT recipients can achieve operational tolerance. Nonetheless, there remains a risk of rejection in LT patients. Maintaining immune homeostasis is thus crucial for improving clinical outcomes in these patients. In mechanism, several immune cells, including dendritic cells, Kupffer cells, myeloid-derived suppressor cells, hepatic stellate cells, regulatory B cells, and CD4 + regulatory T cells (Treg), contribute to achieving tolerance following LT. In terms of Treg, it plays a role in successfully minimizing immunosuppression or achieving tolerance post-LT while also reducing the risk of rejection. Furthermore, the gut microbiome modulates systemic immune functions along the gut-liver axis. Recent studies have explored changes in the microbiome and its metabolites under various conditions, including post-LT, acute rejection, and tolerance. Certain functional microbiomes and metabolites exhibit immunomodulatory functions, such as the augmentation of Treg, influencing immune homeostasis. Therefore, understanding the mechanisms of tolerance in LT, the role of Treg in tolerance and rejection, as well as their interactions with gut microbiome, is vital for the management of LT patients.

Harnessing Kupffer Cell Metabolic Rewiring: Rapamycin-Gliadin Nanoparticle as a Pivotal Strategy for Immune Tolerance in Celiac Disease

Celiac disease (CeD), triggered by gliadin exposure, necessitates therapeutic strategies that establish an antigen-specific immune tolerance. This study explores the therapeutic efficacy and mechanism of rapamycin-gliadin composite nanoparticles (PLN-GR) for CeD treatment. In vivo analyses demonstrated the efficient uptake of PLN-GR by antigen-presenting cells (APCs), particularly Kupffer cells and splenic dendritic cells (DCs), driving their tolerogenic phenotypic transformation. In a murine CeD model, PLN-GR administration significantly enhanced gluten tolerance and mitigated intestinal inflammation, as indicated by reduced paw edema and improved histopathological parameters. Mechanistically, PLN-GR induced macrophage metabolic reprogramming from glycolysis to oxidative phosphorylation, concomitant with elevated serum itaconate levels. This metabolic shift potentiated interorgan immunoregulatory crosstalk, expanding PD-L1+ tolerogenic splenic DCs while suppressing pathogenic Th1 cell populations. Bone marrow-derived macrophages (BMDMs) from Acod1-/- mice (deficient in itaconate synthesis) failed to induce DC tolerance upon PLN-GR treatment. However, supplementation with the itaconate derivative 4-octyl itaconate (4-OI) restored PD-L1 expression in DC2.4 cells in vitro, revealing that itaconate induces and stabilizes the tolerant DC phenotype. These findings underscore PLN-GR as a novel nanotherapeutic platform for CeD, achieving gliadin-specific tolerance through hepatic-splenic immunometabolic reprogramming and itaconate-dependent PD-L1 regulation, thereby offering a translatable strategy for autoimmune disease management.

Tumor-derived erythropoietin acts as an immunosuppressive switch in cancer immunity

Successful cancer immunotherapy requires a patient to mount an effective immune response against tumors; however, many cancers evade the body's immune system. To investigate the basis for treatment failure, we examined spontaneous mouse models of hepatocellular carcinoma (HCC) with either an inflamed T cell-rich or a noninflamed T cell-deprived tumor microenvironment (TME). Our studies reveal that erythropoietin (EPO) secreted by tumor cells determines tumor immunotype. Tumor-derived EPO autonomously generates a noninflamed TME by interacting with its cognate receptor EPOR on tumor-associated macrophages (TAMs). EPO signaling prompts TAMs to become immunoregulatory through NRF2-mediated heme depletion. Removing either tumor-derived EPO or EPOR on TAMs leads to an inflamed TME and tumor regression independent of genotype, owing to augmented antitumor T cell immunity. Thus, the EPO/EPOR axis functions as an immunosuppressive switch for antitumor immunity.

Tolerogenic nanovaccines for the treatment of type I allergic diseases

The high prevalence of type I allergic diseases such as allergic rhinitis, allergic asthma, food allergies, allergic conjunctivitis, and atopic dermatitis has emerged as a significant public health concern globally. Failure of immune tolerance to ordinarily harmless substances or stimulation, and subsequent induction of T helper 2 cells by antigen-presenting cells evokes the allergic immune response, which results in persistent inflammation, tissue damage, and organ function impairment. Current therapeutic approaches for allergic diseases include avoiding allergen exposure, corticosteroids, biologics, etc. However, these strategies only relieve allergic symptoms but hardly prevent the deteriorative progression and may have adverse effects on patients. With the rapid development of nanotechnology and immunology, emerging tolerogenic nanovaccines represent novel approaches with the potential to cure type I allergic diseases rather than merely alleviate symptoms. In this review, we expound the burgeoning field of tolerogenic nanovaccines against type I allergic diseases, highlight various types of antigens employed in constructing allergen extracts, protein/peptide and nucleic acid-based tolerogenic nanovaccines, and discuss their application in allergic rhinitis, allergic asthma, food allergies, allergic conjunctivitis, and atopic dermatitis.

Role of liver-resident NK cells in liver immunity

The tolerogenic immune microenvironment of the liver (the immune system avoids attacking harmless antigens, such as antigens derived from food and gut microbiota) has garnered significant attention in recent years. Inherent immune cells in the liver play a unique role in regulating this microenvironment. Liver-resident natural killer (LrNK) cells, also known as liver type 1 innate lymphoid cells (ILC1s), are a recently discovered subset of immune cells that possess properties distinct from those of conventional NK (cNK) cells. Accumulating evidence suggests that there are significant differences between LrNK and cNK cells, with LrNK cells potentially exhibiting immunosuppressive functions in the liver. This review summarizes the latest findings on LrNK cells, focusing on their phenotype, heterogeneity, plasticity, origin, development, and the required transcription factors. In addition, immune functions of LrNK cells in various liver diseases, including liver cancer, viral infections, liver injury, and cirrhosis, were analyzed. By elucidating the role of LrNK cells in liver immunity, this review aims to enhance our understanding of the mechanisms underlying liver immunity and contribute to the improvement of liver disease treatment.

Integrated analysis reveals an immune evasion prognostic signature for predicting the overall survival in patients with hepatocellular carcinoma

BACKGROUND

The development of immunotherapy has enriched the treatment of hepatocellular carcinoma (HCC), but the efficacy is not as expected, which may be due to immune evasion. Immune evasion is related to the immune microenvironment of HCC, but there is little research on it.

METHODS

We employed unsupervised clustering analysis to categorize patients from TCGA based on 182 immune evasion-related genes (IEGs). We utilized single-sample gene set enrichment analysis (ssGSEA) and CIBERSORT to calculate differences in immune cell infiltration between clusters. The differences in immune cells and immune-related pathways were assessed using GSEA. We constructed an immune escape prognosis signature (IEPS) using univariate Cox and LASSO Cox algorithms and evaluated the predictive performance of IEPS with receiver operating characteristic (ROC) curves and survival curves. Additionally, we established a nomogram for clinical application based on IEPS. IHC validated the expression of Carbamoyl phosphate synthetase 2, Aspartate transcarbamylase, and Dihydroorotase (CAD) and Phosphatidylinositol Glycan Anchor Biosynthesis Class U (PIGU) in HCC. We transfected liver cancer cell lines with siRNA and overexpression plasmids, and confirmed the relationship between CAD, PIGU, and the potential downstream TGF-β1 in HCC using qRT-PCR and Western blot. Finally, we validated the tumor response of CAD overexpression using an animal model.

RESULTS

Unsupervised clustering analysis based on IEGs divided HCC patients from TCGA into two groups. There were significant differences in prognosis and immune characteristics between the two groups of patients. Scoring of TCGA patients using IEPS revealed that higher scores were associated with poorer overall survival (OS). Validation was performed using the ICGC database. TIME analysis indicated that patients in the high-IEPS group were in an immunosuppressive state, possibly due to a significant increase in Treg infiltration. Compared to normal liver cells, HCC cells expressed higher levels of CAD and PIGU. Cellular experimental results showed a positive correlation between CAD, PIGU and the potential downstream TGF-β1 expression. Animal experiments demonstrated that CAD significantly promoted tumor progression, with an increase in Treg infiltration.

CONCLUSION

IEPS has strong prognostic value for HCC patients, and CAD and PIGU provide perspectives on new biomarkers and therapeutic targets for HCC.

mRNA-LNP vaccine strategies: Effects of adjuvants on non-parenchymal liver cells and tolerance

The liver, which plays pivotal roles in metabolism and immunity, often confers tolerance, suppressing immune responses to pathogens. Adjuvanted, lipid nanoparticle-encapsulated mRNA vaccines (mRNA-LNPs) offer a promising approach to overcome immune tolerance. In this study, the immunostimulatory activity of well-documented adjuvants, i.e., 2'3'-cyclic guanosine monophosphate-adenosine monophosphate (cGAMP), resiquimod (R848), and polyinosinic:polycytidylic acid (Poly I:C), on non-parenchymal liver cells was determined. When co-applied with mRNA-loaded LNPs, these adjuvants enhanced immune responses at variable extents. Moreover, the efficiency of mRNA translation in the presence of cGAMP was comparable with the non-adjuvanted control. Repetitive co-application of adjuvants with mRNA-LNPs showed improvement in cellular responses when R848 or R848/cGAMP treatments were used. These findings emphasize the need to delineate the delicate balance between immunomodulatory properties and the efficiency of mRNA translation when selecting adjuvants for mRNA-LNP vaccines and offer insights on how to enhance immunity to infectious diseases and cancers that affect the liver.

Reprogramming the Tolerogenic Immune Response Against Pancreatic Cancer Metastases by Lipid Nanoparticles Delivering a STING Agonist Plus Mutant KRAS mRNA

We demonstrate reprogramming of the tolerogenic immune environment in the liver for mounting an effective immune response against often-fatal pancreatic cancer metastases. This was achieved by engineering a lipid nanoparticle (LNP) to deliver mRNA encoding the KRAS G12D neoantigenic epitope along with cGAMP, a dinucleotide agonist of the stimulator of the interferon genes (STING) pathway, capable of activating a type I interferon response. cGAMP/mKRAS/LNP were synthesized by a microfluidics approach involving nanoprecipitation of mRNA and cGAMP by an ionizable lipid, MC3. Controls included nanoparticles delivering individual components or a wild-type RAS sequence. The dual delivery carrier successfully activated the type I interferon pathway in vitro as well as in vivo, with reprogramming of costimulatory receptor (CD80 and CD86) and MHC-I expression on liver antigen-presenting cells (APC). This allowed the generation of IFN-γ producing cytotoxic T cells, capable of mounting an effective immune response in the metastatic KRAS pancreatic cancer (KPC) mouse model. Noteworthy, intravenous injection of cGAMP/mKRAS/LNP suppressed metastatic growth significantly and prolonged animal survival, both prophylactically and during treatment of established metastases. The protective immune response was mediated by the generation of perforin-releasing CD8+ cytotoxic T cells, engaged in pancreatic cancer cell killing. Importantly, the immune response could also be adoptively transferred by injecting splenocytes (containing memory T cells) from treated into nontreated recipient mice. This study demonstrates that reprogramming the immune-protective niche for metastatic pancreatic cancer can be achieved by the delivery of a STING agonist and mutant KRAS mRNA via ionizable LNPs, offering both prophylactic and therapeutic advantages.

Clinical Guidelines of the Russian Society for the Study of the Liver, Russian Gastroenterological Association, Russian Society for the Prevention of Non-Communicable Diseases, Russian Association of Endocrinologists, Russian Scientific Medical Society of Therapists, National Society of Preventive Cardiology, Russian Association of Gerontologists and Geriatricians on Non-Alcoholic Fatty Liver Disease

Aim. The clinical guidelines are intended to provide information support for making decisions by gastroenterologists, general practitioners and internists that will improve the quality of medical care for patients with non-alcoholic fatty liver disease, taking into account the latest clinical data and principles of evidence-based medicine. Key points. Clinical guidelines contain information about current views on etiology, risk factors and pathogenesis of nonalcoholic fatty liver disease, peculiarities of its clinical course. Also given recommendations provide information on current methods of laboratory and instrumental diagnostics, invasive and non-invasive tools for nonalcoholic fatty liver disease and its clinical phenotypes assessment, approaches to its treatment, considering the presence of comorbidities, features of dispensary monitoring and prophylaxis. The information is illustrated with algorithms of differential diagnosis and physician's actions. In addition, there is information for the patient and criteria for assessing the quality of medical care. Conclusion. Awareness of specialists in the issues of diagnosis, treatment and follow-up of patients with nonalcoholic fatty liver disease contributes to the timely diagnosis and initiation of treatment, which in the long term will significantly affect their prognosis and quality of life.

High‑intensity focused ultrasound thermal ablation boosts the efficacy of immune checkpoint inhibitors in advanced cancers with liver metastases: A single‑center retrospective cohort study

High-intensity focused ultrasound thermal ablation (HIFU) is a novel non-invasive technique in the treatment of liver metastases (LIM) that allows focal destruction and is not affected by dose limits. This retrospective study aimed to explore the efficacy of HIFU in improving survival and the safety of the method in newly diagnosed patients with cancer with LIM who received first-line immune checkpoint inhibitor (ICI) therapy. Between January 2018 and December 2023, data from 438 newly diagnosed patients with cancer and LIM who were treated at Mianyang Central Hospital (Mianyang, China) were reviewed. A total of 94 patients were enrolled in this study, of whom 28 were diagnosed with lung carcinoma, 36 with gastric carcinoma, 11 with esophageal carcinoma, 7 with cholangiocarcinoma and 12 with other malignancies. The patients were divided into groups depending on whether they underwent HIFU. Progression-free survival (PFS), overall survival (OS) and adverse events (AEs) were compared. Clinicopathological features were analyzed using the chi-squared test. Of the 94 patients, 28 received ICI + HIFU as first-line treatment. After a median follow-up of 13.8 months, the median PFS and OS in the HIFU group were 2.38 times [10.95 vs. 4.60 months, 95% confidence interval (CI): 1.087-3.106, P<0.0001] and 1.84 times (19.6 vs. 10.67 months, 95% CI: 1.087-3.106, P=0.0418), respectively, higher than in the group without HIFU. All-cause AEs and immune-mediated AEs were similar between the groups with and without HIFU. However, the incidence of grade 1-2 immune-mediated AEs, troponin elevation, hepatotoxicity and renal dysfunction were more common in the current patients with LIM than those reported previously for the entire population. No immune-mediated AEs of grade ≥3 occurred in either group. HIFU prolonged the PFS and OS of first-line ICI in newly diagnosed patients with advanced cancer with LIM, with manageable safety and tolerability. The efficacy of HIFU in patients with LIM who plan to undergo ICI treatment warrants further prospective clinical investigation.

Neutrophils in MASLD and MASH

Metabolic Dysfunction Associated Steatotic Liver Disease (MASLD) and its progressive form, Metabolic Dysfunction Associated Steatohepatitis (MASH), represent significant health concerns associated with the metabolic syndrome. These conditions are characterized by excessive hepatic fat accumulation, inflammation, and potential progression to cirrhosis and hepatocellular carcinoma. Neutrophils are innate immune cells that play a pivotal role in the development of MASLD and MASH. They can infiltrate the hepatic microenvironment in response to inflammatory cytokines and damage associated molecular patterns (DAMPs) derived from the liver and exacerbate tissue damage by releasing of reactive oxygen species (ROS), cytokines, and neutrophil extracellular traps (NETs). Moreover, neutrophils can disrupt the metabolism of hepatocytes through key factors such as neutrophil elastase (NE) and human neutrophil peptides-1 (HNP-1), leading to inflammation and fibrosis, while myeloperoxidase (MPO) and lipocalin (LCN2) are involved in inflammatory and fibrotic processes. In contrast, neutrophils contribute to liver protection and repair through mechanisms involving microRNA-223 and matrix metalloproteinase 9 (MMP9). This dual role of neutrophils highlights their significance in the pathogenesis of MASLD and MASH. This review summarizes current understanding from recent studies on the involvement of neutrophils in MASLD and MASH. Understanding complex roles of neutrophils within the liver's unique microenvironment offers insights into novel therapeutic strategies, emphasizing the need for further research to explore neutrophil-targeted interventions for managing MASLD and MASH. [BMB Reports 2025; 58(3): 116-123].

Defining an NK Cell-enriched Rejection-like Phenotype in Liver Transplant Biopsies From the INTERLIVER Study

BACKGROUND

Initial analysis of liver transplant biopsies in the INTERLIVER study (ClinicalTrials.gov; unique identifier NCT03193151) using rejection-associated transcripts failed to find an antibody-mediated rejection state (ie, rich in natural killer [NK] cells and with interferon-gamma effects). We recently developed an optimization strategy in lung transplants that isolated an NK cell-enriched rejection-like (NKRL) state that was molecularly distinct from T cell-mediated rejection (TCMR). Here we apply the same strategy to a liver transplant biopsy population.

METHODS

We used this strategy to search for a molecular NKRL state in 765 consented liver transplant biopsies collected at participating international centers for gold-standard histology and molecular assessment by genome-wide microarrays. Validation through a training set-test set approach of an optimized selection of variables as inputs into unsupervised rejection classification identified an NKRL state in livers.

RESULTS

The full model classified 765 biopsies into the following molecular phenotypes, characterized by their gene expression: no-rejection 54%, TCMR 16%, NKRL 13%, and injury 16%. Top TCMR transcripts were expressed in effector T cells; top NKRL transcripts were almost exclusively expressed in NK cells; and both had increased interferon-γ-inducible transcripts, which were more pronounced in TCMR. Most TCMR biopsies had significant parenchymal injury, molecular fibrosis, and abnormal biochemistry. NKRL biopsies had no excess of injury, fibrosis, or biochemistry abnormalities.

CONCLUSIONS

Optimized rejection algorithms indicate that some liver transplants manifest an NKRL state that is well tolerated in the short term postbiopsy and with minimal injury and relatively normal biochemistry, while also underscoring the potential of TCMR to produce extensive parenchymal injury.

The renaissance of oral tolerance: merging tradition and new insights

Oral tolerance is the process by which feeding of soluble proteins induces antigen-specific systemic immune unresponsiveness. Oral tolerance is thought to have a central role in suppressing immune responses to 'harmless' food antigens, and its failure can lead to development of pathologies such as food allergies or coeliac disease. However, on the basis of long-standing experimental observations, the relevance of oral tolerance in human health has achieved new prominence recently following the discovery that oral administration of peanut proteins prevents the development of peanut allergy in at-risk human infants. In this Review, we summarize the new mechanistic insights into three key processes necessary for the induction of tolerance to oral antigens: antigen uptake and transport across the small intestinal epithelial barrier to the underlying immune cells; the processing, transport and presentation of fed antigen by different populations of antigen-presenting cells; and the development of immunosuppressive T cell populations that mediate antigen-specific tolerance. In addition, we consider how related but distinct processes maintain tolerance to bacterial antigens in the large intestine. Finally, we outline the molecular mechanisms and functional consequences of failure of oral tolerance and how these may be modulated to enhance clinical outcomes and prevent disease.

Periodontal disease and cirrhosis: current concepts and future prospects

Periodontal diseases are prevalent among the general population and are associated with several systemic conditions, such as chronic kidney disease and type 2 diabetes mellitus. Chronic liver disease and cirrhosis have also been linked with periodontal disease, an association with complex underlying mechanisms, and with potential prognostic implications. Multiple factors can explain this relevant association, including nutritional factors, alcohol consumption, disruption of the oral-gut-liver axis and associated dysbiosis. Additionally, patients with liver disease have been observed to exhibit poorer oral hygiene practices compared with the general population, potentially predisposing them to the development of periodontal disease. Therefore, it is recommended that all patients with liver disease undergo screening and subsequent treatment for periodontal disease. Treatment of periodontal disease in patients with cirrhosis may help reduce liver-derived inflammatory damage, with recent research indicating a potential benefit in terms of reduced mortality. However, further studies on periodontal disease treatment in patients with liver disease are still warranted to determine optimal management strategies. This narrative review describes current concepts on the association between periodontal disease and chronic liver disease.

Tissue Determinants of Antiviral Immunity in the Liver

The liver is an organ bearing important metabolic and immune functions. Hepatocytes are the main metabolically active cells of the liver and are the target of infection by hepatotropic viruses. Virus-specific CD8 T cells are essential for the control of hepatocyte infection with hepatotropic viruses but may be subject to local regulation of their effector function. Here, we review our current knowledge of the tissue determinants of antiviral immunity in the liver. Liver Sinusoidal Endothelial Cells (LSECs) not only allow through their fenestrations the access of circulating virus-specific CD8 T cells to engage in direct contact with infected hepatocytes without the need for extravasation but also cross-present viral antigens released from infected hepatocytes to these CD8 T cells. Two important features of LSECs and hepatocytes contribute to antiviral immune surveillance and liver failure. First, CD8 T cell immunity targeting LSECs leads to widespread endothelial cell death and results in sinusoidal microcirculation failure, causing fulminant viral hepatitis, whereas immune-mediated loss of hepatocytes is rapidly compensated by the regenerative capacity of the liver. Second, virus-infected hepatocytes support clearance of infection by responding to TNF, which is released from virus-specific CD8 T cells, with the selective induction of apoptosis. This increased sensitivity for TNF-induced death is caused by reduced mitochondrial resilience in virus-infected hepatocytes and may assist antiviral immunity in preferential targeting of virus-infected hepatocytes. Thus, hepatocytes and LSECs actively contribute to the outcome of antiviral CD8 T cell immunity in the liver. The knowledge of the mechanisms determining CD8 T cell control of hepatotropic viral infection will help to improve strategies to increase antiviral immune surveillance.

The immunological interface: dendritic cells as key regulators in metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) refers to a broad spectrum of conditions associating fat accumulation in the liver (steatosis) with varying degrees of inflammation (hepatitis) and fibrosis, which can progress to cirrhosis and potentially cancer (hepatocellular carcinoma). The first stages of these diseases are reversible and the immune system, together with metabolic factors (obesity, insulin resistance, Western diet, etc.), can influence the disease trajectory leading to progression or regression. Dendritic cells are professional antigen-presenting cells that constantly sense environmental stimuli and orchestrate immune responses. Herein, we discuss the existing literature on the heterogeneity of dendritic cell lineages, states, and functions, to provide a comprehensive overview of how liver dendritic cells influence the onset and evolution of MASLD.

Simultaneous combined transplantation: Intricacies in immunosuppression management

Simultaneous combined transplantation (SCT), i.e. the transplantation of two solid organs within the same procedure, can be required when the patients develop more than one end-stage organ failure. The development of SCT over the last 20 years could only be possible thanks to progress in the surgical techniques and in the perioperative management of patients in an ageing population. Performing such major transplant surgeries from the same donor, in a short amount of time, and in critical pathophysiological conditions, is often considered to be counterbalanced by the immune benefits expected from these interventions. However, SCT includes a wide array of different transplant combinations, with each time a different immunological constellation. Recent research offers new insights into the immune mechanisms involved in these different settings. Progress in the understanding of these immunological intricacies help to address the optimal induction and maintenance immunosuppressive treatment strategies. In this review, we summarize the different immunological benefits according to the type of SCT performed. We also incorporate the main outcomes according to the immunological risk at transplantation, and the deleterious impact of preformed or de novo donor-specific antibodies (DSA) in the different types of SCT. Finally, we propose comprehensive and evidence-based induction and maintenance immunosuppression strategies guided by the type of SCT.

HCC Model Induced by P53 and Pten Knockout in HBV-Transgenic Mice Mirrors Human HCC at the Transcriptome Level

With a multitude of HCC mouse models available, choosing the one that most closely resembles human HCC can be challenging. This study addresses this gap by conducting a comprehensive transcriptomic similarity analysis of widely used HCC mouse models. In this study, RNA-seq was performed on a model induced by double knockout of P53 and Pten via CRISPR/Cas9 in HBV-transgenic mice. Additionally, RNA-seq data from 2345 various other models induced by different methods were collected from GEO databases. The gene expression profiles, immune microenvironments, and metabolic pathways of these models were compared with those of human HCC. The analysis revealed distinct transcriptomic features among the different models. The HBV + P53&Pten KO model demonstrated the highest overall similarity to human HCC across various parameters. It shared a high degree of overlap in differentially expression genes (DEGs) between tumor and non-tumor tissues with human HCC, exhibited a transcriptome profile and immune cell infiltration pattern closely resembling human HCC, and showed metabolic alterations similar to those in human HCC. Conversely the DEN + CCl4-induced model showed the lowest similarity to human HCC in transcriptome profiles and DEGs and exhibited a distinct immune microenvironment with high NK cell infiltration, with minimal metabolic differences between tumor and non-tumor tissues. This study highlights the importance of selecting appropriate HCC mouse models for research. The HBV + p53&Pten KO model emerged as the most promising due to its remarkable similarity to human HCC across various aspects.

Evolving understanding of autoimmune mechanisms and new therapeutic strategies of autoimmune disorders

Autoimmune disorders are characterized by aberrant T cell and B cell reactivity to the body's own components, resulting in tissue destruction and organ dysfunction. Autoimmune diseases affect a wide range of people in many parts of the world and have become one of the major concerns in public health. In recent years, there have been substantial progress in our understanding of the epidemiology, risk factors, pathogenesis and mechanisms of autoimmune diseases. Current approved therapeutic interventions for autoimmune diseases are mainly non-specific immunomodulators and may cause broad immunosuppression that leads to serious adverse effects. To overcome the limitations of immunosuppressive drugs in treating autoimmune diseases, precise and target-specific strategies are urgently needed. To date, significant advances have been made in our understanding of the mechanisms of immune tolerance, offering a new avenue for developing antigen-specific immunotherapies for autoimmune diseases. These antigen-specific approaches have shown great potential in various preclinical animal models and recently been evaluated in clinical trials. This review describes the common epidemiology, clinical manifestation and mechanisms of autoimmune diseases, with a focus on typical autoimmune diseases including multiple sclerosis, type 1 diabetes, rheumatoid arthritis, systemic lupus erythematosus, and sjögren's syndrome. We discuss the current therapeutics developed in this field, highlight the recent advances in the use of nanomaterials and mRNA vaccine techniques to induce antigen-specific immune tolerance.

Gastric cancer liver metastasis will reduce the efficacy of immunotherapy

Immune checkpoint inhibitors augment the antitumor activity of T cells by inhibiting the negative regulatory pathway of T cells, leading to notable efficacy in patients with non-small cell lung cancer, melanoma, and other malignancies through immunotherapy utilization. However, secondary malignant liver tumors not only lower the liver's sensitivity to immunotherapy but also trigger systemic immune suppression, resulting in reduced overall effectiveness of immune therapy. Patients receiving immunotherapy for non-small cell lung cancer and melanoma experience reduced response rates, progression-free survival, and overall survival when secondary malignant tumors develop in the liver. Through Liu's retrospective analysis, valuable insights are provided for the future clinical management of these patients. Therefore, in patients with gastric cancer (GC), the occurrence of liver metastasis might be indicative of reduced efficacy of immunotherapy. Overcoming liver immune tolerance mechanisms and their negative impacts allows for the potential benefits of immunotherapy in patients with GC and liver metastasis.

Photocatalytic Carbon Dots-Triggered Pyroptosis for Whole Cancer Cell Vaccines

Manufacturing whole cancer cell vaccines (WCCV) with both biosafety and efficacy is crucial for tumor immunotherapy. Pyroptotic cancer cells, due to their highly immunogenic properties, present a promising avenue for the development of WCCV. However, the successful development of WCCV based on pyroptotic cancer cells is yet to be accomplished. Here, a facile strategy that utilized photocatalytic carbon dots (CDs) to induce pyroptosis of cancer cells for fabricating WCCV is reported. Photocatalytic CDs are capable of generating substantial amounts of hydroxyl radicals and can effectively decrease cytoplasmic pH values under white light irradiation. This process efficiently triggers cancer cell pyroptosis through the reactive oxygen species (ROS)-mitochondria-caspase 3-gasdermin E pathway and the proton motive force-driven mitochondrial ATP synthesis pathway. Moreover, in vitro, these photocatalytic CDs-induced pyroptotic cancer cells (PCIP) can hyperactivate macrophage (M0-M1) with upregulation of major histocompatibility complex class II expression. In vivo, PCIP induced specific immune-preventive effects in melanoma and breast cancer mouse models through anticancer immune memory, demonstrating effective WCCV. This work provides novel insights for inducing cancer cell pyroptosis and bridges the gap in the fabrication of WCCV based on pyroptotic cancer cells.

Consideration on immunotherapy of liver metastases of malignant tumors

In this editorial, we comment on the article "Analysis of the impact of immunotherapy efficacy and safety in patients with gastric cancer and liver metastasis" by Liu et al that was published in the recent issue of the World Journal of Gastrointestinal Surgery. It has prompted us to think and summarize some thoughts on immunotherapy for malignant tumor liver metastasis. Immunotherapy plays a crucial role in the treatment of malignant tumors; however, the presence of liver metastases in advanced tumors may impact its efficacy. Although patients with liver metastases can still benefit from immunotherapy, multiple clinical studies have indicated that, compared to other sites of metastasis, liver metastases may diminish the effectiveness of immunotherapy. The efficacy of immune checkpoint inhibitors in patients with liver metastases often fails to reach the ideal level, primarily due to the liver metastases exploiting the host's peripheral immune tolerance mechanisms to promote systemic CD8(+) T cell exhaustion, resulting in a systemic immune-tolerant environment. This article aims to summarize the reasons for the decreased efficacy of immunotherapy following liver metastasis in various malignant tumors and propose potential clinical strategies for management.

FLT3+ DC inhibits immune rejection via interaction with Treg in liver transplantation

Fms-like tyrosine kinase 3 (FLT3) is a receptor tyrosine kinase (RTK) primarily expressed in hematopoietic stem cells and dendritic cells (DCs). While FLT3 plays a critical role in the proliferation, development and maintenance of DCs, thus influencing immune responses under both normal and pathological conditions, there also exists some evidence that FLT3+DC may be involved with immune responses in liver transplantation (LT). In this study, results from single-cell sequencing data analysis revealed a clear relationship between FLT3+DCs and Regulatory T cells (Tregs) in liver tissue of LT recipients. In peripheral blood samples of LT patients, levels of FLT3+DCs were decreased post-LT-surgery, while Tregs were increased. In a LT mouse model, levels of FLT3+DCs in the liver and bone marrow exhibited an initial time-dependent decrease followed by an increase after LT surgery. Results as obtained with co-culture experiments using mature BMDCs and CD4+ T cells revealed fluctuations in Tregs in response to FLT3 inhibitors and the FLT3 ligand. These findings suggest that FLT3+DCs could emerge as a novel target for mitigating immune rejection in LT.

An herbal formula Shenlian decoction upregulates M1/M2 macrophage proportion in hepatocellular carcinoma by suppressing complement cascade

The immunosuppressive microenvironment is a vital factor for the hepatocellular carcinoma (HCC) progression. However, effective treatment is lacking at current. Shenlian decoction (SLD) is a registered herbal therapy for the HCC treatment, but the underlying mechanism of SLD remains largely elusive. Here, we aimed to explore the anti-tumor effect of SLD in the treatment of HCC. SLD was intragastrically given after the tumor initiation in β-catenin/C-Met or DEN and CCl4 induced HCC mouse model. The tumor growth levels were evaluated by liver weight and histological staining. The tumor-infiltrating immune cells were detected by immunological staining and flow cytometry. The mechanism of the SLD was detected by non-targeted proteomics and verified by a cell co-culture system. The result showed that SLD significantly attenuated HCC progression. SLD promoted macrophage infiltration and increased the M1/M2 macrophage ratio within the tumor tissues. Non-targeted proteomics showed the inhibition of complement C5/C5a signaling is the key mechanism of SLD. Immunological staining showed SLD inhibited C5/C5a expression and C5aR1+ macrophage infiltration. The suggested mechanism was demonstrated by application of C5aR1 inhibitor, PMX-53 in mouse HCC model. Hepatoma cell-macrophage co-culture showed SLD targeted hepatoma cells and inhibited the supernatant-induced macrophage M2 polarization. SLD inhibited AMPK/p38 signaling which is an upstream mechanism of C5 transcription. In conclusion, we found SLD relieved immune-suppressive environment by inhibiting C5 expression. SLD could suppress the C5 secretion in hepatoma cells via inhibition of AMPK/p38 signaling. We suggested that SLD is a potential herbal therapy for the treatment of HCC by alleviating immune-suppressive status.

Neuroimmune modulation in liver pathophysiology

The liver, the largest organ in the human body, plays a multifaceted role in digestion, coagulation, synthesis, metabolism, detoxification, and immune defense. Changes in liver function often coincide with disruptions in both the central and peripheral nervous systems. The intricate interplay between the nervous and immune systems is vital for maintaining tissue balance and combating diseases. Signaling molecules and pathways, including cytokines, inflammatory mediators, neuropeptides, neurotransmitters, chemoreceptors, and neural pathways, facilitate this complex communication. They establish feedback loops among diverse immune cell populations and the central, peripheral, sympathetic, parasympathetic, and enteric nervous systems within the liver. In this concise review, we provide an overview of the structural and compositional aspects of the hepatic neural and immune systems. We further explore the molecular mechanisms and pathways that govern neuroimmune communication, highlighting their significance in liver pathology. Finally, we summarize the current clinical implications of therapeutic approaches targeting neuroimmune interactions and present prospects for future research in this area.

Viral Vector Based Immunotherapy for Peanut Allergy

Food allergy (FA) is estimated to impact up to 10% of the population and is a growing health concern. FA results from a failure in the mucosal immune system to establish or maintain immunological tolerance to innocuous dietary antigens, IgE production, and the release of histamine and other mediators upon exposure to a food allergen. Of the different FAs, peanut allergy has the highest incidence of severe allergic responses, including systemic anaphylaxis. Despite the recent FDA approval of peanut oral immunotherapy and other investigational immunotherapies, a loss of protection following cessation of therapy can occur, suggesting that these therapies do not address the underlying immune response driving FA. Our lab has shown that liver-directed gene therapy with an adeno-associated virus (AAV) vector induces transgene product-specific regulatory T cells (Tregs), eradicates pre-existing pathogenic antibodies, and protects against anaphylaxis in several models, including ovalbumin induced FA. In an epicutaneous peanut allergy mouse model, the hepatic AAV co-expression of four peanut antigens Ara h1, Ara h2, Ara h3, and Ara h6 together or the single expression of Ara h3 prevented the development of a peanut allergy. Since FA patients show a reduction in Treg numbers and/or function, we believe our approach may address this unmet need.

Biomaterial-enhanced treg cell immunotherapy: A promising approach for transplant medicine and autoimmune disease treatment

Regulatory T cells (Tregs) are crucial for preserving tolerance in the body, rendering Treg immunotherapy a promising treatment option for both organ transplants and autoimmune diseases. Presently, organ transplant recipients must undergo lifelong immunosuppression to prevent allograft rejection, while autoimmune disorders lack definitive cures. In the last years, there has been notable advancement in comprehending the biology of both antigen-specific and polyclonal Tregs. Clinical trials involving Tregs have demonstrated their safety and effectiveness. To maximize the efficacy of Treg immunotherapy, it is essential for these cells to migrate to specific target tissues, maintain stability within local organs, bolster their suppressive capabilities, and ensure their intended function's longevity. In pursuit of these goals, the utilization of biomaterials emerges as an attractive supportive strategy for Treg immunotherapy in addressing these challenges. As a result, the prospect of employing biomaterial-enhanced Treg immunotherapy holds tremendous promise as a treatment option for organ transplant recipients and individuals grappling with autoimmune diseases in the near future. This paper introduces strategies based on biomaterial-assisted Treg immunotherapy to enhance transplant medicine and autoimmune treatments.

Immune landscape of hepatocellular carcinoma: From dysregulation of the immune responses to the potential immunotherapies

Hepatocellular carcinoma (HCC) presents a considerable global health burden due to its late diagnosis and high morbidity. The liver's specific anatomical and physiological features expose it to various antigens, requiring precise immune regulation. To the best of our knowledge, this is the first time that a comprehensive overview of the interactions between the immune system and gut microbiota in the development of HCC, as well as the relevant therapeutic approaches are discussed. Dysregulation of immune compartments within the liver microenvironment drives HCC pathogenesis, characterized by elevated regulatory cells such as regulatory T cells (Tregs), myeloid-derived suppressor cells, and M2 macrophages as well as suppressive molecules, alongside reduced number of effector cells like T cells, natural killer cells, and M1 macrophages. Dysbiosis of gut microbiota also contributes to HCC by disrupting intestinal barrier integrity and triggering overactivated immune responses. Immunotherapy approaches, particularly immune checkpoint inhibitors, have exhibited promise in HCC management, yet adoptive cell therapy and cancer vaccination research are in the early steps with relatively less favorable outcomes. Further understanding of immune dysregulation, gut microbiota involvement, and therapeutic combination strategies are essential for advancing precision immunotherapy in HCC.

Role of FoxP3+ Regulatory T Cells in Modulating Immune Responses to Adeno-Associated Virus Gene Therapy

Adeno-associated virus (AAV) gene therapy is making rapid strides owing to its wide range of therapeutic applications. However, development of serious immune responses to the capsid antigen or the therapeutic transgene product hinders its full clinical impact. Immune suppressive (IS) drug treatments have been used in various clinical trials to prevent the deleterious effects of cytotoxic T cells to the viral vector or transgene, although there is no consensus on the best treatment regimen, dosage, or schedule. Regulatory T cells (Tregs) are crucial for maintaining tolerance against self or nonself antigens. Of importance, Tregs also play an important role in dampening immune responses to AAV gene therapy, including tolerance induction to the transgene product. Approaches to harness the tolerogenic effect of Tregs include the use of selective IS drugs that expand existing Tregs, and skew activated conventional T cells into antigen-specific peripherally induced Tregs. In addition, Tregs can be expanded ex vivo and delivered as cellular therapy. Furthermore, receptor engineering can be used to increase the potency and specificity of Tregs allowing for suppression at lower doses and reducing the risk of disrupting protective immunity. Because immune-mediated toxicities to AAV vectors are a concern in the clinic, strategies that can enhance or preserve Treg function should be considered to improve both the safety and efficacy of AAV gene therapy.

Major open questions in the hepatitis B and D field - Proceedings of the inaugural International emerging hepatitis B and hepatitis D researchers workshop

The early and mid-career researchers (EMCRs) of scientific communities represent the forefront of research and the future direction in which a field takes. The opinions of this key demographic are not commonly aggregated to audit fields and precisely demonstrate where challenges lie for the future. To address this, we initiated the inaugural International Emerging Researchers Workshop for the global Hepatitis B and Hepatitis D scientific community (75 individuals). The cohort was split into small discussion groups and the significant problems, challenges, and future directions were assessed. Here, we summarise the outcome of these discussions and outline the future directions suggested by the EMCR community. We show an effective approach to gauging and accumulating the ideas of EMCRs and provide a succinct summary of the significant gaps remaining in the Hepatitis B and Hepatitis D field.

Siglec-H-/- Plasmacytoid Dendritic Cells Protect Against Acute Liver Injury by Suppressing IFN-γ/Th1 Response and Promoting IL-21+ CD4 T Cells

BACKGROUND & AIMS

Siglec-H is a receptor specifically expressed in mouse plasmacytoid dendritic cells (pDCs), which functions as a negative regulator of interferon-α production and plays a critical role in pDC maturation to become antigen-presenting cells. The function of pDCs in autoimmune and inflammatory diseases has been reported. However, the effect of Siglec-H expression in pDCs in liver inflammation and diseases remains unclear.

METHODS

Using the model of concanavalin A-induced acute liver injury (ALI), we investigated the Siglec-H/pDCs axis during ALI in BDCA2 transgenic mice and Siglec-H-/- mice. Anti-BDCA2 antibody, anti-interleukin (IL)-21R antibody, and Stat3 inhibitor were used to specifically deplete pDCs, block IL21 receptor, and inhibit Stat3 signaling, respectively. Splenocytes and purified naive CD4 T cells and bone marrow FLT3L-derived pDCs were cocultured and stimulated with phorbol myristate acetate/ionomycin and CD3/CD28 beads, respectively.

RESULTS

Data showed that specific depletion of pDCs aggravated concanavalin A-induced ALI. Remarkably, alanine aminotransferase, hyaluronic acid, and proinflammatory cytokines IL6 and tumor necrosis factor-α levels were lower in the blood and liver of Siglec-H knockout mice. This was associated with attenuation of both interferon-γ/Th1 response and Stat1 signaling in the liver of Siglec-H knockout mice while intrahepatic IL21 and Stat3 signaling pathways were upregulated. Blocking IL21R or Stat3 signaling in Siglec-H knockout mice restored concanavalin A-induced ALI. Finally, we observed that the Siglec-H-null pDCs exhibited immature and immunosuppressive phenotypes (CCR9LowCD40Low), resulting in reduction of CD4 T-cell activation and promotion of IL21+CD4 T cells in the liver.

CONCLUSIONS

During T-cell-mediated ALI, Siglec-H-null pDCs enhance immune tolerance and promote IL21+CD4 T cells in the liver. Targeting Siglec-H/pDC axis may provide a novel approach to modulate liver inflammation and disease.

Dendritic Cells: A Bridge between Tolerance Induction and Cancer Development in Transplantation Setting

Dendritic cells (DCs) are a heterogeneous group of antigen-presenting cells crucial for fostering allograft tolerance while simultaneously supporting host defense against infections and cancer. Within the tumor microenvironment, DCs can either mount an immune response against cancer cells or foster immunotolerance, presenting a dual role. In immunocompromised individuals, posttransplant malignancies pose a significant health concern, with DCs serving as vital players in immune responses against cancer cells. Both recipient- and donor-derived DCs play a critical role in the rejection process, infiltrating the transplanted organ and sustaining T-cell responses. The use of immunosuppressive drugs represents the predominant approach to control this immunological barrier in transplanted organs. Evidence has shed light on the immunopharmacology of these drugs and novel strategies for manipulating DCs to promote allograft survival. Therefore, comprehending the mechanisms underlying this intricate microenvironment and the effects of immunosuppressive therapy on DCs is crucial for developing targeted therapies to reduce graft failure rates. This review will delve into the fundamental immunobiology of DCs and provide a detailed exploration of their clinical significance concerning alloimmune responses and posttransplant malignancies.

Hepatocytes and the art of killing Plasmodium softly

The Plasmodium parasites that cause malaria undergo asymptomatic development in the parenchymal cells of the liver, the hepatocytes, prior to infecting erythrocytes and causing clinical disease. Traditionally, hepatocytes have been perceived as passive bystanders that allow hepatotropic pathogens such as Plasmodium to develop relatively unchallenged. However, now there is emerging evidence suggesting that hepatocytes can mount robust cell-autonomous immune responses that target Plasmodium, limiting its progression to the blood and reducing the incidence and severity of clinical malaria. Here we discuss our current understanding of hepatocyte cell-intrinsic immune responses that target Plasmodium and how these pathways impact malaria.

How Future Pharmacologic Therapies for Celiac Disease Will Complement the Gluten-Free Diet

The only proven treatment for celiac disease is adherence to a strict, lifelong, gluten-free diet. However, complete dietary gluten avoidance is challenging and a substantial number of patients do not respond fully, clinically, or histologically, despite their best efforts. As celiac disease is common and its central pathophysiology is well elucidated, it has become attractive for drug development to address the limitations of dietary treatment. Most efforts address nonresponsive celiac disease, defined as continued symptoms and/or signs of disease activity despite a gluten-free diet, and the more severe forms of refractory celiac disease, types I and II. An increasing spectrum of therapeutic approaches target defined mechanisms in celiac disease pathogenesis and some have advanced to current phase 2 and 3 clinical studies. We discuss these approaches in terms of potential efficiency, practicability, safety, and need, as defined by patients, regulatory authorities, health care providers, and payors.

Evolving landscape of treatments targeting the microenvironment of liver metastases in non-small cell lung cancer

ABSTRACT

Liver metastases (LMs) are common in lung cancer. Despite substantial advances in diagnosis and treatment, the survival rate of patients with LM remains low as the immune-suppressive microenvironment of the liver allows tumor cells to evade the immune system. The impact of LMs on the outcomes of immune checkpoint inhibitors in patients with solid tumors has been the main focus of recent translational and clinical research. Growing evidence indicates that the hepatic microenvironment delivers paracrine and autocrine signals from non-parenchymal and parenchymal cells. Overall, these microenvironments create pre- and post-metastatic conditions for the progression of LMs. Herein, we reviewed the epidemiology, physiology, pathology and immunology, of LMs associated with non-small cell lung cancer and the role and potential targets of the liver microenvironment in LM in each phase of metastasis. Additionally, we reviewed the current treatment strategies and challenges that should be overcome in preclinical and clinical investigations. These approaches target liver elements as the basis for future clinical trials, including combinatorial interventions reported to resolve hepatic immune suppression, such as immunotherapy plus chemotherapy, immunotherapy plus radiotherapy, immunotherapy plus anti-angiogenesis therapy, and surgical resection.

Tolerance-inducing therapies in coeliac disease - mechanisms, progress and future directions

Coeliac disease is an autoinflammatory condition caused by immune reactions to cereal gluten proteins. Currently, the only available treatment for the condition is a lifelong avoidance of gluten proteins in the diet. There is an unmet need for alternative therapies. Coeliac disease has a strong association with certain HLA-DQ allotypes (DQ2.5, DQ2.2 and DQ8), and these disease-associated HLA-DQ molecules present deamidated gluten peptides to gluten-specific CD4+ T cells. The gluten-specific CD4+ T cells are the drivers of the immune reactions leading to coeliac disease. Once established, the clonotypes of gluten-specific CD4+ T cells persist for decades, explaining why patients must adhere to a gluten-free diet for life. Given the key pathogenic role of gluten-specific CD4+ T cells, tolerance-inducing therapies that target these T cells are attractive for treatment of the disorder. Lessons learned from coeliac disease might provide clues for treatment of other HLA-associated diseases for which the disease-driving antigens are unknown. Thus, intensive efforts have been and are currently implemented to bring an effective tolerance-inducing therapy for coeliac disease. This Review discusses mechanisms of the various approaches taken, summarizing the progress made, and highlights future directions in this field.

Based on the prognosis model of immunogenes, the prognosis model was constructed to predict the invasion of immune genes and immune cells related to primary liver cancer and its experimental validation

Background

Primary liver cancer (PLC) is a prevalent malignancy of the digestive system characterized by insidious symptom onset and a generally poor prognosis. Recent studies have highlighted a significant correlation between the initiation and prognosis of liver cancer and the immune function of PLC patients.

Purpose

Revealing the expression of PLC-related immune genes and the characteristics of immune cell infiltration provides assistance for the analysis of clinical pathological parameters and prognosis of PLC patients.

Methods

PLC-related differentially expressed genes (DEGs) with a median absolute deviation (MAD > 0.5) were identified from TCGA and GEO databases. These DEGs were intersected with immune-related genes (IRGs) from the ImmPort database to obtain PLC-related IRGs. The method of constructing a prognostic model through immune-related gene pairs (IRGPs) is used to obtain IRGPs and conduct the selection of central immune genes. The central immune genes obtained from the selection of IRGPs are validated in PLC. Subsequently, the relative proportions of 22 types of immune cells in different immune risk groups are evaluated, and the differential characteristics of PLC-related immune cells are verified through animal experiments.

Results

Through database screening and the construction of an IRGP prognosis model, 84 pairs of IRGPs (P < 0.001) were ultimately obtained. Analysis of these 84 IRGPs revealed 11 central immune genes related to PLC, showing differential expression in liver cancer tissues compared to normal liver tissues. Results from the CiberSort platform indicate differential expression of immune cells such as naive B cells, macrophages, and neutrophils in different immune risk groups. Animal experiments demonstrated altered immune cell proportions in H22 tumor-bearing mice, validating findings from peripheral blood and spleen homogenate analyses.

Conclusion

Our study successfully predicted and validated PLC-related IRGs and immune cells, suggesting their potential as prognostic indicators and therapeutic targets for PLC.

The role of dendritic cells in MASH: friends or foes?

Dendritic cells (DCs) are major antigen-presenting cells that connect innate and adaptive immunity. Hepatic DCs are less activated and contribute to maintain the tolerogenic environment of the liver under steady state. Several studies indicated DCs in metabolic dysfunction-associated steatohepatitis (MASH), representing a substantial burden on healthcare systems due to its association with liver-related morbidity and mortality. Studies highlighted the potential disease-promoting role of liver DCs in the development of MASH while other experimental systems suggested their protective role. This review discusses this controversy and the current understanding of how DCs affect the pathogenesis of MASH.

Cirrhosis-downregulated LSECtin can be retrieved by cytokines, shifts the TLR-induced LSECs secretome and correlates with the hepatic Th response

BACKGROUND AND AIMS

We evaluated tolerogenic C-type lectin LSECtin loss in cirrhosis and its potential regulation by cytokines.

METHODS

Liver tissue from patients with cirrhosis and healthy controls, immortalised and generated LSECtin-CRISPR immortalised LSECs, and murine primary LSECs from the CCl4 model were handled.

RESULTS

LSECtin expression was reduced in liver tissue from cirrhotic patients, and it decreased from compensated to decompensated disease. Increased phosphorylation of MAPK, Akt and NFkB was observed upon LSECtin stimulation in LSEC murine cell line, showing a pattern of inflammatory and chemotactic cytokines either restrained (IL-10, CCL4) or unrestrained (TNF-α, IL-1β, IL-6, CCL2). CD44 attenuated whereas LAG-3 increased all substrates phosphorylation in combination with TLR4 and TLR2 ligands except for NFkB. TNF-α, IL-1 β, IL-6 and CCL2 were restrained by LSECtin crosslinking on TLRs studied. Conversely, IL-10 and CCL4 were upregulated, suggesting a LSECtin-TLRs synergistic effect. Also, LSECtin was significantly induced after IL-13 stimulation or combined with anti-inflammatory cytokines in cirrhotic and immortalised LSECs. Th17 and regulatory T cells were progressively increased in the hepatic tissue from compensated to decompensated patients. A significant inverse correlation was present between gene expression levels of CLEC4G/LSECtin and RORγT and FOXP3 in liver tissues.

CONCLUSION

LSECtin restrains TLR proinflammatory secretome induced on LSECs by interfering immune response control, survival and MAPKs signalling pathways. The cytokine-dependent induction of LSECtin and the association between LSECtin loss and Th17 cell subset expansion in the liver, provides a solid background for exploring LSECtin retrieval as a mechanism to reprogram LSEC homeostatic function hampered during cirrhosis.

The "Domino effect" in MASLD: The inflammatory cascade of steatohepatitis

Metabolic dysfunction-associated steatotic liver disease (MASLD) is an increasingly common complication of obesity, affecting over a quarter of the global adult population. A key event in the pathophysiology of MASLD is the development of metabolic-associated steatohepatitis (MASH), which greatly increases the chances of developing cirrhosis and hepatocellular carcinoma. The underlying cause of MASH is multifactorial, but accumulating evidence indicates that the inflammatory process in the hepatic microenvironment typically follows a pattern that can be roughly divided into three stages: (1) Detection of hepatocyte stress by tissue-resident immune cells including γδ T cells and CD4-CD8- double-negative T cells, followed by their secretion of pro-inflammatory mediators, most notably IL-17A. (2) Recruitment of pro-inflammatory cells, mostly of the myeloid lineage, and initiation of inflammation through secretion of effector-type cytokines such as TNF, TGF-β, and IL-1β. (3) Escalation of the inflammatory response by recruitment of lymphocytes including Th17, CD8 T, and B cells leading to chronic inflammation, hepatic stellate cell activation, and fibrosis. Here we will discuss these three stages and how they are consecutively linked like falling domino tiles to the pathophysiology of MASH. Moreover, we will highlight the clinical potential of inflammation as a biomarker and therapeutic target for the treatment of MASLD.

The double roles of T cell-mediated immune response in the progression of MASLD

Metabolic dysfunction-associated steatotic liver disease(MASLD), formerly known as non-alcoholic fatty liver disease(NAFLD), has become a major cause of chronic liver disease and a significant risk factor for hepatocellular carcinoma, which poses a huge burden on global public health and economy. MASLD includes steatotic liver disease, steatohepatitis, and cirrhosis, and the latter two cause great harm to human health and life, even complicated with liver cancer. Immunologic mechanism plays a major role in promoting its development into hepatitis and cirrhosis. Now more and more evidences show that T cells play an important role in the progression of MASLD. In this review, we discuss the double roles of T cells in MASLD from the perspective of T cell response pathways, as well as new evidences regarding the possible application of immunomodulatory therapy in MASH.

Longterm Outcome of Therapeutic Vaccination with a Third Generation Pre-S/S HBV Vaccine (PreHevbrioR) of Chronically HBV Infected Patients

Several antiviral treatment regimens for chronic hepatitis B (CHB) virus infection have been shown to be effective in suppressing viral load and reducing the risk of hepatocellular injury and its complications. It has been hypothesized that high levels of circulating HBV surface antigen(s) may lead to immune tolerance against HBV and contribute to chronic carriership. Conversely, low-level HBsAg may create a window for the reconstitution of an HBV-specific immune response through vaccination and control of infection. Previous studies in non-responders to yeast-derived HBV vaccines, using a third-generation pre-S/S vaccine, have led to up to 95% anti-HBs seroconversion. This report evaluates the long-term outcome after experimental vaccination with a pre-S/S HBV vaccine intended as a therapeutic intervention in chronic HBV carriers. Four low-level HBsAg carriers (<500 IU/mL) were vaccinated three to seven times with 20 μg PreHevbrioR. Three out of four carriers eliminated HBsAg completely and seroconverted to anti-HBs. One patient seroconverted to anti-HBs but remained with a borderline HBsAg titer (10 IU/mL). Serum anti-HBs levels following repeated vaccination varied between 27 and >1000 IU/L, respectively. Long-term observation (>6 years) showed that after discontinuing NUC treatment for at least two years, HBsAg and HBV DNA remained negative with anti-HBs positive titers ranging between 80 and >1000 IU/L. Based on our preliminary observations, there is a rationale to further evaluate the role of this vaccine as a therapeutic agent.

Mitochondria: the gatekeepers between metabolism and immunity

Metabolism and immunity are crucial monitors of the whole-body homeodynamics. All cells require energy to perform their basic functions. One of the most important metabolic skills of the cell is the ability to optimally adapt metabolism according to demand or availability, known as metabolic flexibility. The immune cells, first line of host defense that circulate in the body and migrate between tissues, need to function also in environments in which nutrients are not always available. The resilience of immune cells consists precisely in their high adaptive capacity, a challenge that arises especially in the framework of sustained immune responses. Pubmed and Scopus databases were consulted to construct the extensive background explored in this review, from the Kennedy and Lehninger studies on mitochondrial biochemistry of the 1950s to the most recent findings on immunometabolism. In detail, we first focus on how metabolic reconfiguration influences the action steps of the immune system and modulates immune cell fate and function. Then, we highlighted the evidence for considering mitochondria, besides conventional cellular energy suppliers, as the powerhouses of immunometabolism. Finally, we explored the main immunometabolic hubs in the organism emphasizing in them the reciprocal impact between metabolic and immune components in both physiological and pathological conditions.

Endotoxin Inflammatory Action on Cells by Dysregulated-Immunological-Barrier-Linked ROS-Apoptosis Mechanisms in Gut-Liver Axis

Our study highlighted the immune changes by pro-inflammatory biomarkers in the gut-liver-axis-linked ROS-cell death mechanisms in chronic and acute inflammations when gut cells are exposed to endotoxins in patients with hepatic cirrhosis or steatosis. In duodenal tissue samples, gut immune barrier dysfunction was analyzed by pro-inflammatory biomarker expressions, oxidative stress, and cell death by flow cytometry methods. A significant innate and adaptative immune system reaction was observed as result of persistent endotoxin action in gut cells in chronic inflammation tissue samples recovered from hepatic cirrhosis with the A-B child stage. Instead, in patients with C child stage of HC, the endotoxin tolerance was installed in cells, characterized by T lymphocyte silent activation and increased Th1 cytokines expression. Interesting mechanisms of ROS-cell death were observed in chronic and acute inflammation samples when gut cells were exposed to endotoxins and immune changes in the gut-liver axis. Late apoptosis represents the chronic response to injury induction by the gut immune barrier dysfunction, oxidative stress, and liver-dysregulated barrier. Meanwhile, necrosis represents an acute and severe reply to endotoxin action on gut cells when the immune system reacts to pro-inflammatory Th1 and Th2 cytokines releasing, offering protection against PAMPs/DAMPs by monocytes and T lymphocyte activation. Flow cytometric analysis of pro-inflammatory biomarkers linked to oxidative stress-cell death mechanisms shown in our study recommends laboratory techniques in diagnostic fields.

The ABC of Immune-Mediated Hepatitis during Immunotherapy in Patients with Cancer: From Pathogenesis to Multidisciplinary Management

Immune-mediated hepatotoxicity (IMH) is not-so-rare complication during treatment with immune checkpoint inhibitors (ICIs). This narrative review aims to report the current knowledge on hepatic immune-related adverse events (irAEs) during immunotherapy from pathogenesis to multidisciplinary management. The majority of cases of IMH are asymptomatic and only a few patients may have clinical conditions. The severity of IMH is usually stratified according to Common Terminology for Clinical Adverse Events (CTCAE) criteria, but these scores may overestimate the clinical severity of IMH compared to the Drug-Induced Liver Injury Network (DILIN) scale. The differential diagnosis of IMH is challenging because the elevated liver enzymes can be due to a number of etiologies such as viral infection, autoimmune and metabolic diseases, liver metastases, biliary diseases, and other drugs. The cornerstones of IMH management are represented by withholding or delaying ICI administration and starting immunosuppressive therapy. A multidisciplinary team, including oncologists, hepatologists, internists, and emergency medicine physicians, is essential for the management of IMH.

MSCs-derived extracellular vesicles alleviate sepsis-associated liver dysfunction by inhibiting macrophage glycolysis-mediated inflammatory response

Sepsis-associated liver dysfunction (SALD) aggravates the disease progression and prognosis of patients. Macrophages in the liver play a crucial role in the occurrence and development of SALD. Human umbilical cord mesenchymal stem cells (MSCs), by secreting extracellular vesicles (EVs), show beneficial effects in various inflammatory diseases. However, whether MSC-derived EVs (MSC-EVs) could ameliorate the inflammatory response in liver macrophages and the underlying mechanisms remain unclear. In this study, a mouse model of sepsis induced by lipopolysaccharide (LPS) challenge was used to investigate the immunomodulatory functions of MSC-EVs in SALD. LPS-stimulated primary Kupffer cells (KCs) and Raw264.7 were used to further explore the potential mechanisms of MSC-EVs in regulating the inflammatory response of macrophages. The results showed that MSC-EVs alleviated liver tissue injury and facilitated the polarization of M1 to M2 macrophages. Further in vitro studies confirmed that MSC-EVs treatment significantly downregulated the expression of several enzymes related to glycolysis and reduced the glycolytic flux by inhibiting hypoxia-inducible factor 1α (HIF-1α) expression, thus effectively inhibiting the inflammatory responses of macrophages. These findings reveal that the application of MSC-EVs might be a potential therapeutic strategy for treating SALD.

Tolerogenic Nano-/Microparticle Vaccines for Immunotherapy

Autoimmune diseases, allergies, transplant rejections, generation of antidrug antibodies, and chronic inflammatory diseases have impacted a large group of people across the globe. Conventional treatments and therapies often use systemic or broad immunosuppression with serious efficacy and safety issues. Tolerogenic vaccines represent a concept that has been extended from their traditional immune-modulating function to induction of antigen-specific tolerance through the generation of regulatory T cells. Without impairing immune homeostasis, tolerogenic vaccines dampen inflammation and induce tolerogenic regulation. However, achieving the desired potency of tolerogenic vaccines as preventive and therapeutic modalities calls for precise manipulation of the immune microenvironment and control over the tolerogenic responses against the autoantigens, allergens, and/or alloantigens. Engineered nano-/microparticles possess desirable design features that can bolster targeted immune regulation and enhance the induction of antigen-specific tolerance. Thus, particle-based tolerogenic vaccines hold great promise in clinical translation for future treatment of aforementioned immune disorders. In this review, we highlight the main strategies to employ particles as exciting tolerogenic vaccines, with a focus on the particles' role in facilitating the induction of antigen-specific tolerance. We describe the particle design features that facilitate their usage and discuss the challenges and opportunities for designing next-generation particle-based tolerogenic vaccines with robust efficacy to promote antigen-specific tolerance for immunotherapy.

The novel mechanism facilitating chronic hepatitis B infection: immunometabolism and epigenetic modification reprogramming

Hepatitis B Virus (HBV) infections pose a global public health challenge. Despite extensive research on this disease, the intricate mechanisms underlying persistent HBV infection require further in-depth elucidation. Recent studies have revealed the pivotal roles of immunometabolism and epigenetic reprogramming in chronic HBV infection. Immunometabolism have identified as the process, which link cell metabolic status with innate immunity functions in response to HBV infection, ultimately contributing to the immune system's inability to resolve Chronic Hepatitis B (CHB). Within hepatocytes, HBV replication leads to a stable viral covalently closed circular DNA (cccDNA) minichromosome located in the nucleus, and epigenetic modifications in cccDNA enable persistence of infection. Additionally, the accumulation or depletion of metabolites not only directly affects the function and homeostasis of immune cells but also serves as a substrate for regulating epigenetic modifications, subsequently influencing the expression of antiviral immune genes and facilitating the occurrence of sustained HBV infection. The interaction between immunometabolism and epigenetic modifications has led to a new research field, known as metabolic epigenomics, which may form a mutually reinforcing relationship with CHB. Herein, we review the recent studies on immunometabolism and epigenetic reprogramming in CHB infection and discuss the potential mechanisms of persistent HBV infection. A deeper understanding of these mechanisms will offer novel insights and targets for intervention strategies against chronic HBV infection, thereby providing new hope for the treatment of related diseases.