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

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.

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.

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.

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.

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.

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.

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.

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.

Flow Cytometry Assessment of Lymphocyte Populations Infiltrating Liver Tumors

Tissue-resident and recruited immune cells are essential mediators of natural and therapy-induced immunosurveillance of liver neoplasia. This idea has been recently reinforced by the clinical approval of immune checkpoint inhibitors for the immunotherapy of hepatocellular carcinoma and cholangiocarcinoma. Such research progress relies on the in-depth characterization of the immune populations that are present in pre-neoplastic and neoplastic hepatic lesions. A convenient technology for advancing along this path is high-dimensional cytometry.In this chapter, we present a protocol to assess the subtype and differentiation state of hepatic lymphocyte populations by multicolor immunofluorescence staining and flow cytometry. We detail the steps required for viability assessment and immune cell phenotyping of single-cell suspensions of liver cells by means of surface and intracellular staining of more than a dozen markers of interest. This protocol does not require prior removal of debris and dead cells and allows to process multiple samples in parallel. The procedure includes the use of a fixative-resistant viability dye that allows cell fixation and permeabilization after cell surface staining and before intracellular staining and data acquisition on a flow cytometer. Moreover, we provide a panel of fluorochrome-labeled antibodies designed for the characterization of lymphocytic subsets that can be adapted to distinct experimental settings. Finally, we present an overview of the post-staining pipeline, including data acquisition on a flow cytometer and tools for post-acquisition analyses.

Immune checkpoint inhibitors in hepatocellular carcinoma: A review of current clinical trials

Hepatocellular carcinoma (HCC) is the most common primary liver cancer with a poor prognosis due to advanced disease presentation or recurrence despite curative-intent resection. Since the approval of sorafenib in 2007, few systemic therapies offered a significant improvement in treatment outcomes. Over the last 3 years, however, rapid advancements in the field of immunotherapy have led to approval of checkpoint inhibitors in 2020 for use in advanced HCC. Since then, a few other clinical trials have shown promising results in the adjuvant and neoadjuvant setting. The objective of this review is to summarize data from existing clinical trials evaluating the use of systemic immune checkpoint inhibitors in HCC and to follow the natural evolution of this development across the metastatic, adjuvant, and neoadjuvant landscapes.

Liver-Targeting Nanoplatforms for the Induction of Immune Tolerance

Liver-targeting nanoparticles have emerged as a promising platform for the induction of immune tolerance by taking advantage of the liver's unique tolerogenic properties and nanoparticles' physicochemical flexibility. Such an approach provides a versatile solution to the treatment of a diversity of immunologic diseases. In this review, we begin by assessing the design parameters integral to cell-specific targeting and the tolerogenic induction of nanoplatforms engineered to target the four critical immunogenic hepatic cells, including liver sinusoidal epithelial cells (LSECs), Kupffer cells (KCs), hepatic stellate cells (HSCs), and hepatocytes. We also include an overview of multiple therapeutic strategies in which nanoparticles are being studied to treat many allergies and autoimmune disorders. Finally, we explore the challenges of using nanoparticles in this field while highlighting future avenues to expand the therapeutic utility of liver-targeting nanoparticles in autoimmune processes.

AAV Immunotoxicity: Implications in Anti-HBV Gene Therapy

Hepatitis B virus (HBV) has afflicted humankind for decades and there is still no treatment that can clear the infection. The development of recombinant adeno-associated virus (rAAV)-based gene therapy for HBV infection has become important in recent years and research has made exciting leaps. Initial studies, mainly using mouse models, showed that rAAVs are non-toxic and induce minimal immune responses. However, several later studies demonstrated rAAV toxicity, which is inextricably associated with immunogenicity. This is a major setback for the progression of rAAV-based therapies toward clinical application. Research aimed at understanding the mechanisms behind rAAV immunity and toxicity has contributed significantly to the inception of approaches to overcoming these challenges. The target tissue, the features of the vector, and the vector dose are some of the determinants of AAV toxicity, with the latter being associated with the most severe adverse events. This review discusses our current understanding of rAAV immunogenicity, toxicity, and approaches to overcoming these hurdles. How this information and current knowledge about HBV biology and immunity can be harnessed in the efforts to design safe and effective anti-HBV rAAVs is discussed.

Effect of infiltrating immune cells in tumor microenvironment on metastasis of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most lethal and prevalent human malignancies, leading to poor prognosis due to its high recurrence and metastasis rates. In recent years it has become increasingly evident that the tumor microenvironment (TME) plays an important role in tumor progression and metastasis. Tumor microenvironment (TME) refers to the complex tissue environment of tumor occurrence and development. Here, we summarize the development of HCC and the role of cellular and non-cellular components of the TME in the metastasis HCC, with particular reference to tumor-infiltrating immune cells. We also discuss some of the possible therapeutic targets for the TME and the future prospectives of this evolving field. SIGNIFICANCE: This review provides a comprehensive analysis of the role of the infiltrating immune cells in TME in the metastasis of HCC and highlights the future outlook for targeted therapy of the TME in the context of recent experiments revealing a number of therapeutic targets targeting the TME.

The bidirectional immune crosstalk in metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) is an unabated risk factor for end-stage liver diseases with no available therapies. Dysregulated immune responses are critical culprits of MASLD pathogenesis. Independent contributions from either the innate or adaptive arms of the immune system or their unidirectional interplay are commonly studied in MASLD. However, the bidirectional communication between innate and adaptive immune systems and its impact on MASLD remain insufficiently understood. Given that both innate and adaptive immune cells are indispensable for the development and progression of inflammation in MASLD, elucidating pathogenic contributions stemming from the bidirectional interplay between these two arms holds potential for development of novel therapeutics for MASLD. Here, we review the immune cell types and bidirectional pathways that influence the pathogenesis of MASLD and highlight potential pharmacologic approaches to combat MASLD based on current knowledge of this bidirectional crosstalk.

Deciphering the tumour immune microenvironment of hepatocellular carcinoma

Current treatments for hepatocellular carcinoma (HCC) are less effective and prone to recurrence after surgery, so it's needed to seek new ideas for its therapy. Tumour immune microenvironment (TME) is crucial for the pathogenesis, development and metastasis of HCC. Interactions between immune cells and tumour cells significantly impact responses to immunotherapies and patient prognosis. In recent years, immunotherapies for HCC have shown promising potential, but the response rate is still unsatisfactory. Understanding their cross-talks is helpful for selecting potential therapeutic targets, predicting immunotherapy responses, determining immunotherapy efficacy, identifying prognostic markers and selecting individualized treatment options. In this paper, we reviewed the research advances on the roles of immune cells and multi-omic research associated with HCC pathogenesis and therapy, and future perspectives on TME.

Modulatory effects of bisphenol A on the hepatic immune response

The liver is a primary line of defense for protection from external substances next to the intestinal barrier. As a result, the hepatic immune system plays a central role in liver pathophysiology. Bisphenol A (BPA) is one of the most common endocrine disrupting chemicals and is primarily metabolized in the liver. Due to its ability to bind to estrogen receptors, BPA is well known to possess estrogenic activity and disrupt reproductive functions. The phase I and Phase II metabolism reactions of BPA mainly occur in the liver with the help of enzymes including cytochrome P450 (CYP), uridine 5'-diphospho-glucuronosyltransferase-glucuronosyltransferases, sulfotransferases, and glutathione-S-transferases. Although the majority of BPA is excreted after conjugation by these enzymes, untransformed BPA induces the production of reactive oxygen species through disruption of the enzymatic complex CYP, lipid accumulation, mitochondrial dysfunction, endoplasmic reticulum stress and inflammatory injury in the liver. Moreover, it has been proposed to possess a potential immunomodulatory effect. Indeed, several in vivo and in vitro studies have reported that low doses of BPA increase the population of T cells with type 1 T helper (Th1), Th2, and Th17 cells. Although the current literature lacks clear evidence on the mechanisms by which BPA is involved in T cell mediated immune responses, recent multi-omics studies suggest that it may directly interact with the antigen processing and presentation pathways. In this review, we first discuss the metabolism of BPA in the liver, before exploring currently available data on its effects on liver injury. Finally, we review its modulatory effects on the hepatic immune response, as well as potential mechanisms. By conducting this review, we aim to improve understanding on the relationship between BPA exposure and immune-related liver injury, with a focus on the antigen processing and presentation pathway and T cell-mediated response in the liver.

Dendritic cells in liver transplantation immune response

Dendritic cells (DCs) are the most powerful antigen presenting cells (APCs), they are considered one of the key regulatory factors in the liver immune system. There is currently much interest in modulating DC function to improve transplant immune response. In liver transplantation, DCs participate in both the promotion and inhibition of the alloreponse by adopting different phenotypes and function. Thus, in this review, we discussed the origin, maturation, migration and pathological effects of several DC subsets, including the conventional DC (cDC), plasmacytoid DC (pDC) and monocyte-derived DC (Mo-DC) in liver transplantation, and we summarized the roles of these DC subsets in liver transplant rejection and tolerance. In addition, we also outlined the latest progress in DC-based related treatment regimens. Overall, our discussion provides a beneficial resource for better understanding the biology of DCs and their manipulation to improve the immune adaptability of patients in transplant status.

Spleen-targeted neoantigen DNA vaccine for personalized immunotherapy of hepatocellular carcinoma

Neoantigens are emerging as attractive targets to develop personalized cancer vaccines, but their immunization efficacy is severely hampered by their restricted accessibility to lymphoid tissues where immune responses are initiated. Leveraging the capability of red blood cells (RBCs) to capture and present pathogens in peripheral blood to the antigen-presenting cells (APCs) in spleen, we developed a RBC-driven spleen targeting strategy to deliver DNA vaccine encoding hepatocellular carcinoma (HCC) neoantigen. The DNA vaccine-encapsulating polymeric nanoparticles that were intentionally hitchhiked on the preisolated RBCs could preferentially accumulate in the spleen to promote the neoantigen expression by APCs, resulting in the burst of neoantigen-specific T-cell immunity to prevent tumorigenesis in a personalized manner, and slow down tumor growth in the established aggressively growing HCC. Remarkably, when combined with anti-PD-1, the vaccine achieved complete tumor regression and generated a robust systemic immune response with long-term tumor-specific immunological memory, which thoroughly prevented tumor recurrence and spontaneous lung metastasis. This study offers a prospective strategy to develop personalized neoantigen vaccines for augmenting cancer immunotherapy efficiency in immune "cold" HCC.

CD4+ T-cell subsets in autoimmune hepatitis: A review

Autoimmune hepatitis (AIH) is a chronic autoimmune liver disease that can lead to hepatocyte destruction, inflammation, liver fibrosis, cirrhosis, and liver failure. The diagnosis of AIH requires the identification of lymphoblast cell interface hepatitis and serum biochemical abnormalities, as well as the exclusion of related diseases. According to different specific autoantibodies, AIH can be divided into AIH-1 and AIH-2. The first-line treatment for AIH is a corticosteroid and azathioprine regimen, and patients with liver failure require liver transplantation. However, the long-term use of corticosteroids has obvious side effects, and patients are prone to relapse after drug withdrawal. Autoimmune diseases are characterized by an imbalance in immune tolerance of self-antigens, activation of autoreactive T cells, overactivity of B cells, and increased production of autoantibodies. CD4+ T cells are key players in adaptive immunity and can secrete cytokines, activate B cells to produce antibodies, and influence the cytotoxicity of CD8+ T cells. According to their characteristics, CD4+ T cells can be divided into different subsets. In this review, we discuss the changes in T helper (Th)1, Th2, Th17, Th9, Th22, regulatory T cell, T follicular helper, and T peripheral helper cells and their related factors in AIH and discuss the therapeutic potential of targeting CD4+ T-cell subsets in AIH.

Phenotypic and Functional Heterogeneity of Monocytes and Macrophages

Macrophages are likely to be the first immune cells to have appeared during the evolution of multicellular organisms [...].

Oral administration of ovalbumin protects mice from concanavalin A-induced hepatitis through suppression of interferon-gamma responses

The liver is a tolerogenic organ that exhibits hypo-responsiveness to antigens circulating in the portal vein. Antigens that are orally administered at high doses reach the liver. In our previous study, we demonstrated that administering ovalbumin (OVA) orally at high doses generates unique CD4+ T cells and tolerogenic dendritic cells, both of which can suppress T helper type 1 (Th1) responses, in the livers of two groups of mice: DO11.10 mice with transgenic CD4+ T cell receptors for OVA and BALB/c mice that received OVA-specific CD4+ T cells through adoptive transfer. This study aimed to investigate whether oral administration of OVA at high doses inhibits the development of hepatitis in the presence of OVA-specific CD4+ T cells. Oral administration of OVA at high doses inhibited the development of OVA-specific and concanavalin A (Con A)-induced hepatitis in DO11.10 mice, and these effects were associated with the downregulation of Th1 responses. Furthermore, the adoptive transfer of CD4+ T cells from the liver of OVA-fed DO11.10 mice inhibited the development of Con A-induced hepatitis in recipient BALB/c mice through the downregulation of Th1 responses. Finally, oral administration of OVA at high doses inhibited the development of Con A-induced hepatitis in BALB/c mice bearing naïve OVA-specific CD4+ T cells. These results suggest that the oral administration of antigens at high doses suppresses Th1-mediated hepatitis in an antigen-non-specific manner in the presence of antigen-specific CD4+ T cells.

IFNγ and CTLA-4 Drive Hepatic CD4 T-Cell Tolerance and Protection From Autoimmunity in Mice

BACKGROUND & AIMS

The liver has a distinct capacity to induce immune tolerance to hepatic antigens. Although liver tolerance can be advantageous for preventing autoimmune and inflammatory diseases, it also can be detrimental by preventing immune surveillance of infected or malignant cells. Here, we investigated the immune mechanisms that establish hepatic tolerance.

METHODS

Tolerance was investigated in C-reactive protein (CRP)-myelin basic protein (MBP) mice expressing the neuroantigen MBP in hepatocytes, providing profound resistance to MBP-induced neuroinflammation. Tolerance induction was studied after transfer of MBP-specific CD4 T cells into CRP-MBP mice, and tolerance mechanisms were tested using depleting or blocking antibodies.

RESULTS

Although tolerant CRP-MBP mice display increased numbers of forkhead box P3+ regulatory T cells, we here found them not essential for the maintenance of hepatic tolerance. Instead, upon MBP recognition in the liver, MBP-specific T cells became activated to produce interferon (IFN)γ, which, in turn, induced local up-regulation of recruitment molecules, including Chemokine (C-X-C motif) ligand9 and its receptor C-X-C motif chemokine receptor3, facilitating endothelial translocation and redirection of MBP-specific T cells into the hepatic parenchyma. There, the translocated MBP-specific CD4 T cells partly converted into interleukin 10-producing type 1 regulatory T cells, and significantly up-regulated the expression of immune checkpoint molecules, notably cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). Intriguingly, although liver tolerance was not affected by impairment of interleukin 10 signaling, concomitant blockade of IFNγ and CTLA-4 abrogated hepatic tolerance induction to MBP, resulting in neuroinflammatory autoimmune disease in these mice.

CONCLUSIONS

IFNγ-mediated redirection of autoreactive CD4 T cells into the liver and up-regulation of checkpoint molecules, including CTLA-4, were essential for tolerance induction in the liver, hence representing a potential treatment target for boosting or preventing liver tolerance.

Recent updates on the role of the gut-liver axis in the pathogenesis of NAFLD/NASH, HCC, and beyond

The gut and the liver are anatomically and physiologically connected, and this connection is called the "gut-liver axis," which exerts various influences on liver physiology and pathology. The gut microbiota has been recognized to trigger innate immunity and modulate the liver immune microenvironment. Gut microbiota influences the physiological processes in the host, such as metabolism, by acting on various signaling receptors and transcription factors through their metabolites and related molecules. The gut microbiota has also been increasingly recognized to modulate the efficacy of immune checkpoint inhibitors. In this review, we discuss recent updates on gut microbiota-associated mechanisms in the pathogenesis of chronic liver diseases such as NAFLD and NASH, as well as liver cancer, in light of the gut-liver axis. We particularly focus on gut microbial metabolites and components that are associated with these liver diseases. We also discuss the role of gut microbiota in modulating the response to immunotherapy in liver diseases.

Stimulating Antitumoral Immunity by Percutaneous Cryoablation and Combination Immunoadjuvant Therapy in a Murine Model of Hepatocellular Carcinoma

PURPOSE

To test the hypothesis that antitumoral immunity can be induced after cryoablation (cryo) of hepatocellular carcinoma (HCC) through coadministration of the immunostimulant CpG and an immune checkpoint (programmed cell death 1 [PD-1]) inhibitor.

MATERIALS AND METHODS

Sixty-three immunocompetent C57BL/6J mice were generated with 2 orthotopic HCC tumor foci: 1 for treatment and 1 to observe for antitumoral immunity. Tumors were treated with incomplete cryo alone or intratumoral CpG and/or a PD-1 inhibitor. The primary endpoint was death or when the following criteria for sacrifice were met: tumor > 1 cm (determined using ultrasound) or moribund state. Antitumoral immunity was assessed using flow cytometry and histology (tumor and liver) as well as enzyme-linked immunosorbent assay (serum). Analysis of variance was used for statistical comparisons.

RESULTS

At 1 week, the nonablated satellite tumor growth was reduced by 1.9-fold (P = .047) in the cryo + CpG group and by 2.8-fold (P = .007) in the cryo + CpG + PD-1 group compared with that in the cryo group. Compared with cryo alone, the time to tumor progression to endpoints was also prolonged for cryo + CpG + PD-1 and cryo + CpG mice, with log-rank hazard ratios of 0.42 (P = .031) and 0.27 (P < .001), respectively. Flow cytometry and histology showed increased cytotoxic T-cell infiltration (P = .002) and serum levels of the proinflammatory cytokine interferon-γ (P = .015) in tumors and serum of cryo + CpG mice compared with those in tumors and serum of mice treated with cryo alone. High serum levels of the anti-inflammatory cytokine tumor growth factor-β and the proangiogenesis chemokine C-X-C motif chemokine ligand 1 were correlated with a shorter time to endpoints and faster tumor growth.

CONCLUSIONS

Cryo combined with the immunostimulant CpG promoted cytotoxic T-cell infiltration into tumors, slowed tumor growth, and prolonged the time to progression to endpoints in an aggressive murine HCC model.

Sterile inflammation in liver transplantation

Sterile inflammation is the immune response to damage-associated molecular patterns (DAMPs) released during cell death in the absence of foreign pathogens. In the setting of solid organ transplantation, ischemia-reperfusion injury results in mitochondria-mediated production of reactive oxygen and nitrogen species that are a major cause of uncontrolled cell death and release of various DAMPs from the graft tissue. When properly regulated, the immune response initiated by DAMP-sensing serves as means of damage control and is necessary for initiation of recovery pathways and re-establishment of homeostasis. In contrast, a dysregulated or overt sterile inflammatory response can inadvertently lead to further injury through recruitment of immune cells, innate immune cell activation, and sensitization of the adaptive immune system. In liver transplantation, sterile inflammation may manifest as early graft dysfunction, acute graft failure, or increased risk of immunosuppression-resistant rejection. Understanding the mechanisms of the development of sterile inflammation in the setting of liver transplantation is crucial for finding reliable biomarkers that predict graft function, and for development of therapeutic approaches to improve long-term transplant outcomes. Here, we discuss the recent advances that have been made to elucidate the early signs of sterile inflammation and extent of damage from it. We also discuss new therapeutics that may be effective in quelling the detrimental effects of sterile inflammation.

Role of Kupffer cells in tolerance induction after liver transplantation

Currently, liver transplantation has reached a level of maturity where it is considered an effective treatment for end-stage liver disease and can significantly prolong the survival time of patients. However, acute and chronic rejection remain major obstacles to its efficacy. Although long-term use of immunosuppressants can prevent rejection, it is associated with serious side effects and significant economic burden for patients. Therefore, the investigation of induced immune tolerance holds crucial theoretical significance and socio-economic value. In fact, the establishment of immune tolerance in liver transplantation is intricately linked to the unique innate immune system of the liver. Kupffer cells, as a crucial component of this system, play a pivotal role in maintaining the delicate balance between inflammatory response and immune tolerance following liver transplantation. The important roles of different functions of Kupffer cells, such as phagocytosis, cell polarization, antigen presentation and cell membrane proteins, in the establishment of immune tolerance after transplantation is comprehensively summarized in this paper. Providing theoretical basis for further study and clinical application of Kupffer cells in liver transplantation.

Engineered anti-PDL1 with IFNα targets both immunoinhibitory and activating signals in the liver to break HBV immune tolerance

OBJECTIVE

The purpose of this study is to develop an anti-PDL1-based interferon (IFN) fusion protein to overcome the chronic hepatitis B virus (HBV)-induced immune tolerance, and combine this immunotherapy with a HBV vaccine to achieve the functional cure of chronic hepatitis B (CHB) infection.

DESIGN

We designed an anti-PDL1-IFNα heterodimeric fusion protein, in which one arm was derived from anti-PDL1 antibody and the other arm was IFNα, to allow targeted delivery of IFNα into the liver by anti-PDL1 antibody. The effect of the anti-PDL1-IFNα heterodimer on overcoming hepatitis B surface antigen (HBsAg) vaccine resistance was evaluated in chronic HBV carrier mice.

RESULTS

The anti-PDL1-IFNα heterodimer preferentially targeted the liver and resulted in viral suppression, the PD1/PDL1 immune checkpoint blockade and dendritic cell activation/antigen presentation to activate HBsAg-specific T cells, thus breaking immune tolerance in chronic HBV carrier mice. When an HBsAg vaccine was administered soon after anti-PDL1-IFNα heterodimer treatment, we observed strong anti-HBsAg antibody and HBsAg-specific T cell responses for efficient HBsAg clearance in chronic HBV carrier mice that received the combination treatment but not in those that received either single treatment.

CONCLUSIONS

Targeting the liver with an engineered anti-PDL1-IFNα heterodimer can break HBV-induced immune tolerance to an HBsAg vaccine, offering a promising translatable therapeutic strategy for the functional cure of CHB.

Avasimibe can cooperate with a DC-targeting and integration-deficient lentivector to induce stronger HBV specific T cytotoxic response by regulating cholesterol metabolism

We have reported a lentivector which could effectively induce HBV-specific cytotoxic T lymphocytes (CTLs). Avasimibe is an inhibitor of acetyl-CoA acetyltransferase-1 (ACAT1), and has been shown to enhance T lymphocyte cytotoxicity on tumor cells. However, the role of avasimibe in lentivector-induced HBV-specific T cytotoxic response remains unknown. Based on previous study, we constructed an integration-deficient lentivector LVDC-ID-HBV (harboring HBcAg expression), and the in vitro experiments showed that the combination of avasimibe exhibited better efficacy in inducing HBV-specific CTL responses including cell proliferation, production of cytokines, as well as CTL killing activities. Mechanism experiments showed that increasing cell membrane cholesterol levels by MβCD-coated cholesterol or ACAT1 inhibition efficiently promoted TCR clustering, signaling transduction and immunological synapse formation, thereby mediating augmented CTL responses. Nevertheless, the depletion of plasma membrane cholesterol with MβCD led to obviously decreased CTL responses. The avasimibe-mediated strengthened immune effects were also determined in animal experiments and the results were in agreement with those from the in vitro research. In particular, the in vivo CTL killing activities were identified by the CFSE or BV-labeled splenocyte lysis assay. Moreover, the experiments in HBV transgenic mice showed that the LVDC-ID-HBV plus avasimibe group demonstrated the lowest serum HBsAg and HBV DNA levels, as well as the lowest expression of HBsAg and HBcAg in liver tissues. We concluded that the HBV-specific CTL immune responses could be potentiated by avasimibe through regulating plasma membrane cholesterol levels. Avasimibe may be a potential adjuvant for lentivector vaccine against HBV infection.

Harnessing Nanomaterials for Cancer Sonodynamic Immunotherapy

Immunotherapy has made remarkable strides in cancer therapy over the past decade. However, such emerging therapy still suffers from the low response rates and immune-related adverse events. Various strategies have been developed to overcome these serious challenges. Therein, sonodynamic therapy (SDT), as a non-invasive treatment, has received ever-increasing attention especially in the treatment of deep-seated tumors. Significantly, SDT can effectively induce immunogenic cell death to trigger systemic anti-tumor immune response, termed sonodynamic immunotherapy. The rapid development of nanotechnology has revolutionized SDT effects with robust immune response induction. As a result, more and more innovative nanosonosensitizers and synergistic treatment modalities are established with superior efficacy and safe profile. In this review, the recent advances in cancer sonodynamic immunotherapy are summarized with a particular emphasis on how nanotechnology can be explored to harness SDT for amplifying anti-tumor immune response. Moreover, the current challenges in this field and the prospects for its clinical translation are also presented. It is anticipated that this review can provide rational guidance and facilitate the development of nanomaterials-assisted sonodynamic immunotherapy, helping to pave the way for next-generation cancer therapy and eventually achieve a durable response in patients.

Liver metastasis from colorectal cancer: pathogenetic development, immune landscape of the tumour microenvironment and therapeutic approaches

Colorectal cancer liver metastasis (CRLM) is one of the leading causes of death among patients with colorectal cancer (CRC). Although immunotherapy has demonstrated encouraging outcomes in CRC, its benefits are minimal in CRLM. The complex immune landscape of the hepatic tumour microenvironment is essential for the development of a premetastatic niche and for the colonisation and metastasis of CRC cells; thus, an in-depth understanding of these mechanisms can provide effective immunotherapeutic targets for CRLM. This review summarises recent studies on the immune landscape of the tumour microenvironment of CRLM and highlights therapeutic prospects for targeting the suppressive immune microenvironment of CRLM.

Immune System and Hepatocellular Carcinoma (HCC): New Insights into HCC Progression

According to the WHO's recently released worldwide cancer data for 2020, liver cancer ranks sixth in morbidity and third in mortality among all malignancies. Hepatocellular carcinoma (HCC), the most common kind of liver cancer, accounts approximately for 80% of all primary liver malignancies and is one of the leading causes of death globally. The intractable tumor microenvironment plays an important role in the development and progression of HCC and is one of three major unresolved issues in clinical practice (cancer recurrence, fatal metastasis, and the refractory tumor microenvironment). Despite significant advances, improved molecular and cellular characterization of the tumor microenvironment is still required since it plays an important role in the genesis and progression of HCC. The purpose of this review is to present an overview of the HCC immune microenvironment, distinct cellular constituents, current therapies, and potential immunotherapy methods.

Liver in infections: a single-cell and spatial transcriptomics perspective

The liver is an immune organ that plays a vital role in the detection, capture, and clearance of pathogens and foreign antigens that invade the human body. During acute and chronic infections, the liver transforms from a tolerant to an active immune state. The defence mechanism of the liver mainly depends on a complicated network of intrahepatic and translocated immune cells and non-immune cells. Therefore, a comprehensive liver cell atlas in both healthy and diseased states is needed for new therapeutic target development and disease intervention improvement. With the development of high-throughput single-cell technology, we can now decipher heterogeneity, differentiation, and intercellular communication at the single-cell level in sophisticated organs and complicated diseases. In this concise review, we aimed to summarise the advancement of emerging high-throughput single-cell technologies and re-define our understanding of liver function towards infections, including hepatitis B virus, hepatitis C virus, Plasmodium, schistosomiasis, endotoxemia, and corona virus disease 2019 (COVID-19). We also unravel previously unknown pathogenic pathways and disease mechanisms for the development of new therapeutic targets. As high-throughput single-cell technologies mature, their integration into spatial transcriptomics, multiomics, and clinical data analysis will aid in patient stratification and in developing effective treatment plans for patients with or without liver injury due to infectious diseases.

AFP deletion leads to anti-tumorigenic but pro-metastatic roles in liver cancers with concomitant CTNNB1 mutations

HCC remains one of the most prevalent and deadliest cancers. Serum AFP level is a biomarker for clinical diagnosis of HCC, instead the contribution of AFP to HCC development is clearly highly complex. Here, we discussed the effect of AFP deletion in the tumorigenesis and progression of HCC. AFP deletion in HepG2 cells inhibited the cell proliferation by inactivating PI3K/AKT signaling. Surprisingly, AFP KO HepG2 cells appeared the increasing metastatic capacity and EMT phenotype, which was attributed to the activation of WNT5A/β-catenin signal. Further studies revealed that the activating mutations of CTNNB1 was closely related with the unconventional pro-metastatic roles of AFP deletion. Consistently, the results of DEN/CCl4-induced HCC mouse model also suggested that AFP knockout suppressed the growth of HCC primary tumors, but promoted lung metastasis. Despite the discordant effect of AFP deletion in HCC progression, a drug candidate named OA showed the potent suppression of HCC tumor growth by interrupting AFP-PTEN interaction and, importantly, reduced the lung metastasis of HCC via angiogenesis suppression. Thus, this study demonstrates an unconventional effect of AFP in HCC progression, and suggests a potent candidate strategy for HCC therapy.

Safety and tolerability of KAN-101, a liver-targeted immune tolerance therapy, in patients with coeliac disease (ACeD): a phase 1 trial

BACKGROUND

Coeliac disease management is limited to strict adherence to a gluten-free diet with no approved therapies. This first-in-human phase 1 study evaluated the safety and tolerability of KAN-101, a liver-targeting glycosylation signature conjugated to a deaminated gliadin peptide designed to induce immune tolerance to gliadin.

METHODS

Adults (aged 18-70 years) with biopsy-confirmed, HLA-DQ2.5 genotype coeliac disease were enrolled from clinical research units and hospitals in the USA. Part A of the trial was an open-label, single ascending dose study of intravenous KAN-101 using sentinel dosing in evaluation of the following cohorts: 0·15 mg/kg, 0·3 mg/kg, 0·6 mg/kg, 1·2 mg/kg, and 1·5 mg/kg. Following safety monitoring committee review of the 0·3 mg/kg dose level in part A, part B was initiated as a randomised, placebo-controlled, multiple ascending dose study. In part B, interactive response technology was used to randomly assign (5:1) patients to receive intravenous KAN-101 (0·15 mg/kg, 0·3 mg/kg, or 0·6 mg/kg) or placebo following a 1:1 assignment of the first two eligible patients in each cohort for sentinel dosing. Patients in part B received three administrations of KAN-101 or placebo followed by a 3-day oral gluten challenge (9 g per day) 1 week after completing dosing. Study personnel and patients were masked to treatment assignments in part B, and not in part A. The primary endpoint was the incidence and severity of adverse events with escalating doses of KAN-101, assessed in all patients who received any amount of study drug based on dose level received. The secondary endpoint was assessment of plasma concentrations and pharmacokinetic parameters of KAN-101 following single and multiple doses, assessed in all patients who received at least one dose and had one or more values for drug concentration. This study is registered with ClinicalTrials.gov, NCT04248855, and is completed.

FINDINGS

Between Feb 7, 2020, and Oct 8, 2021, 41 patients were enrolled at ten US sites. 14 patients were assigned to part A (four 0·15 mg/kg, three 0·3 mg/kg, three 0·6 mg/kg, three 1·2 mg/kg, one 1·5 mg/kg) and 27 patients to part B (six 0·15 mg/kg with two placebo, seven 0·3 mg/kg with two placebo, and eight 0·6 mg/kg with two placebo). Treatment-related adverse events were reported in 11 (79%) of 14 patients in part A and 18 (67%) of 27 in part B (placebo two [33%] of six patients; KAN-101 16 [76%] of 21 patients), were grade 2 or lower, and were mild to moderate in severity. The most commonly observed adverse events were nausea, diarrhoea, abdominal pain, and vomiting, consistent with symptoms had by patients with coeliac disease on gluten ingestion. No grade 3-4 adverse events, serious adverse events, dose-limiting toxicities, or deaths occurred. Pharmacokinetic analyses showed KAN-101 was cleared from systemic circulation within roughly 6 h with a geometric mean half-life of 3·72 min (CV% 6·5%) to 31·72 min (83·7%), and no accumulation with repeated dosing.

INTERPRETATION

KAN-101 has an acceptable safety profile in patients with coeliac disease with no dose-limiting toxicities and no maximum tolerated dose was observed. Rapid systemic clearance of KAN-101 was observed and no accumulation on repeated dosing. A future study will evaluate the safety and efficacy, including biomarker responses with a gluten challenge, of KAN-101 at doses 0·6 mg/kg and greater in patients with coeliac disease.

FUNDING

Kanyos Bio.

The role of myeloid-derived suppressor cells in liver cancer

MDSCs are immature myeloid immune cells, which accumulate in models of liver cancer to reduce effector immune cell activity, contribute to immune escape and treatment resistance. The accumulation of MDSCs suppresses the role of CTL and the killing effects of NK cells, induces the accumulation of Treg cells, and blocks the antigen presentation of DCs, thus promoting the progression of liver cancer. Recently, immunotherapy has emerged a valuable approach following chemoradiotherapy in the therapy of advanced liver cancer. A considerable increasing of researches had proved that targeting MDSCs has become one of the therapeutic targets to enhance tumor immunity. In preclinical study models, targeting MDSCs have shown encouraging results in both alone and in combination administration. In this paper, we elaborated immune microenvironment of the liver, function and regulatory mechanisms of MDSCs, and therapeutic approaches to target MDSCs. We also expect these strategies to supply new views for future immunotherapy for the treatment of liver cancer.