Immune surveillance by the liver

The restoration of immunity characterized by the recovery of myeloid dendritic cells represent a favorable response to methylprednisolone therapy for HBV-ACLF patients: A prospective cohort study

BACKGROUND

The use of methylprednisolone (MP) is still controversial for hepatitis B virus related acute-on-chronic liver failure (HBV-ACLF). We aimed to explore the change in dendritic cells (DCs) during MP treatment in HBV-ACLF to guide the use of MP to improve patient's prognosis.

METHODS

Patients with HBV-ACLF were prospectively allocated to groups given methylprednisolone intravenously (1.5 mg/kg/day for the first 3 days, 1 mg/kg/day for the second 2 days, and 0.5 mg/kg/day for the last 2 days, MP group, n = 36) plus standard treatment or standard treatment only (CM group, n = 34). The phenotype [myeloid and plasmacytoid DCs (mDCs, pDCs)] and function of DCs (IL-12 and IFN-α production) were measured at baseline (0d), 3d, 7d, 10d, 14d, 28d, and then monthly until 3 months. Patients' survival was assessed until day 90.

RESULTS

The 3-month survival rate was significantly higher in the MP group than the control (72.0 % vs. 35.5 %，P < 0.01). The phenotype and function of DCs were suppressed in the MP group. The mDCs counts was lower in non-survivors compared to survivors at baseline. Patients with a decline in mDCs counts at the 7th day and a continuous increase in mDCs counts from the 10th day presented a better outcome for patients with MP treatment. Bilirubin was the only relative factor for the restoration of mDCs in the MP group (odds ratio, 0.991; 95 % confidence interval, 0.984-0.999; P = 0.023).

CONCLUSIONS

Methylprednisolone could improve the outcome of HBV-ACLF by inhibiting the circulating mDCs counts. And the recovery of mDCs counts after methylprednisolone treatment could represent a favorable response. We can consider monitoring the circulating DCs counts to guide the use of MP in HBV-ACLF in order to improve patient outcomes.

The heterogeneity of cirrhosis - systemically assessed endotypes described by fibrosis, apoptosis, and immunoregulatory-related biomarkers

BACKGROUND

Given the heterogeneity of advanced chronic liver disease, assessing disease activity-related biomarkers could aid in classifying cirrhosis endotypes for better patient monitoring and treatment selection.

AIM

To investigate cirrhosis endotypes described by disease activity biomarkers related to fibrogenesis, immune cell activity, apoptosis, and systemic inflammation.

METHODS

The study included plasma EDTA samples from 106 participants with mild, moderate, and severe liver cirrhosis undergoing hepatic venous pressure gradient (HVPG) measurements and 39 healthy control participants. The biomarkers nordicPROC3™ (fibrogenesis), GDF-15, CK18 M30 (apoptosis), CRP (systemic inflammation), nordicCPa9-HNE™ (neutrophil activity), and nordicVICM™ (macrophage activity) were measured.

RESULTS

PROC3, GDF-15, CK18 M30, and CRP increased with cirrhosis severity (p < 0.05-p < 0.0001) and the degree of portal hypertension (p < 0.05-p < 0.01). CPa9-HNE decreased from mild to moderate and mild to severe cirrhosis (p < 0.01-0.0001) and correlated with HVPG (r=-0.53, p < 0.0001). VICM decreased from mild to severe cirrhosis (p < 0.01). A heatmap clustered analysis revealed four potential cirrhosis endotypes, reflecting underlying biological processes.

CONCLUSION

Assessing markers related to active fibrogenesis, apoptosis, immune cell activity, and systemic inflammation revealed distinct molecular patterns among patients with cirrhosis. These findings suggest the presence of potential disease endotypes that could inform future strategies for patient monitoring, treatment selection, and prognostic assessment in cirrhosis management.

A combined "eat me/don't eat me" strategy based on exosome for acute liver injury treatment

Drug-induced liver injury (DILI) involves multifaceted pathogenesis, necessitating effective therapeutic strategies. Wnt2, secreted by liver sinusoidal endothelial cell (LSEC), activates the Wnt/β-catenin signaling pathway to promote hepatocyte proliferation after injury. To address the dual challenges of targeted delivery and phagocytosis evasion, we develop a combined "eat me/don't eat me" strategy. RLTRKRGLK (RLTR) peptide-functionalized exosomes are engineered by inserting DMPE-PEG2000-CRLTRKRGLK into the lipid membrane of exosome derived from bEnd.3 cell. Surface-displayed RLTR mediates exosomal enrichment in LSEC, while CD47 engineering reduces macrophage clearance via "don't eat me" signaling. Then, lentiviral transfection enables stable encapsulation of functional Wnt2 mRNA into ExoCD47 (designated Wnt2@ExoCD47). In both acetaminophen (APAP) and dimethylnitrosamine (DMN)-induced murine liver injury models, RLTR-Wnt2@ExoCD47 demonstrates LSEC-specific targeting and significant hepatoprotection. This engineered exosome platform provides a therapeutic strategy for DILI.

Hepatocellular carcinoma: pathogenesis, molecular mechanisms, and treatment advances

Hepatocellular Carcinoma (HCC), a highly prevalent malignancy, poses a significant global health challenge. Its pathogenesis is intricate and multifactorial, involving a complex interplay of environmental and genetic factors. Viral hepatitis, excessive alcohol consumption, and cirrhosis are known to significantly elevate the risk of developing HCC. The underlying biological processes driving HCC are equally complex, encompassing aberrant activation of molecular signaling pathways, dysregulation of hepatocellular differentiation and angiogenesis, and immune dysfunction. This review delves into the multifaceted nature of HCC, exploring its etiology and the intricate molecular signaling pathways involved in its development. We examine the role of immune dysregulation in HCC progression and discuss the potential of emerging therapeutic strategies, including immune-targeted therapy and tumor-associated macrophage interventions. Additionally, we explore the potential of traditional Chinese medicine (TCM) monomers in inhibiting tumor growth. By elucidating the complex interplay of factors contributing to HCC, this review aims to provide a comprehensive understanding of the disease and highlight promising avenues for future research and therapeutic development.

Establishment and characterization of liver-specific Apoa4-Cre and Cyp2c11-Cre rat models in juvenile and adult stages

BACKGROUND

Liver diseases are a major contributor to both morbidity and mortality. Conditional knockout animals are always produced through crossing floxed animals with a tissue-specific Cre animal. The use of floxed rat resource has rapidly increased, but the liver-specific Cre rat lines for studying liver diseases and interested genes are limited, especially in a spatially and temporally restricted manner.

METHODS

RNA sequencing and real-time polymerase chain reaction (PCR) were used to screen and confirm the presence of liver-specific genes. Apoa4-Cre rats and Cyp2c11-Cre rats were produced by CRISPR/Cas9 knockin. Rosa26-imCherry rats were employed to hybridize with the Cre rats to obtain the Apoa4-Cre/Rosa26-imCherry and Cyp2c11-Cre/Rosa26-imCherry rats. The temporal and spatial patterns of Cre expression were determined by the observation of red fluorescence on tissue sections. Hematoxylin-eosin stain was used to evaluate the liver histopathologic changes. The blood biochemical analysis of several liver enzymes and liver lipid profile was performed to evaluate the liver function of Cre rats.

RESULTS

Apoa4 and Cyp2c11 were identified as two liver-specific genes. Apoa4-Cre and Cyp2c11-Cre rats were produced and hybridized with Rosa26-imCherry rats. The red fluorescence indicated that the Cre recombinases were specially expressed in the juvenile and adult liver and not in other organs of two hybridized rats. All the blood biochemical parameters except low-density lipoprotein (LDL) did not change significantly in the Cre rats. No histological alterations were detected in the livers of the Cre rats.

CONCLUSIONS

Liver-specific Apoa4-Cre and Cyp2c11-Cre rats have been established successfully and could be used to study gene knockout, specifically in juvenile and adult liver.

Myeloid cell path to malignancy: insights into liver cancer

Clinically approved treatments for advanced liver cancer often lack potency because of the heterogeneous characteristics of hepatocellular carcinoma (HCC). This complexity is largely driven by context-dependent inflammatory responses brought on by diverse etiologies, such as metabolic dysfunction-associated steatohepatitis (MASH), the genetic makeup of cancer cells, and the versatile adaptability of immune cells, such as myeloid cells. In this review, we discuss the evolutionary dynamics of the immune landscape, particularly that of liver-resident Kupffer cells (KCs), TREM2+, and SPP1+ macrophages with an active role during liver disease progression, which eventually fuels hepatocarcinogenesis. We highlight exploitable immunomodulatory avenues amenable to mitigate both the inherent pathological characteristics of liver cancers and the associated external factors that favor malignancy, paving a roadmap toward improving the management and therapeutic outcome for patients with HCC.

Interaction between cecal microbiota and liver genes of laying ducks with different residual feed intake

BACKGROUND

The gut microbiota exerts a critical influence on energy metabolism homeostasis and productive performance in avian species. Given the diminishing availability of arable land and intensifying competition for finite resources between livestock production and human populations, the agricultural sector faces dual imperatives to enhance productive efficiency while mitigating ecological footprints. Within this paradigm, optimizing nutrient assimilation efficiency in commercial waterfowl operations emerges as a strategic priority. This investigation employs an integrated multi-omics approach framework (metagenomic, metabolomic, and transcriptomic analyses) to elucidate the mechanistic relationships between cecal microbial consortia and feed conversion ratios in Shan Partridge ducks.

RESULTS

Based on the analysis of metagenome data, a total of 34 phyla, 1033 genera and 3262 species of bacteria were identified by metagenomic sequencing analysis. At the phylum level, 31 phylums had higher mean abundance in the low residual feed intake ( LRFI) group than in the high residual feed intake (HRFI) group. Among them, the expression of microbiome Elusimicrobiota was significantly higher in the LRFI group than in the HRFI group (P < 0.05). And we also found a significant differences in secondary metabolites biosynthesis, transport, and catabolism pathways between the two groups in microbial function (P < 0.05). Based on metabolomic analysis, 17 different metabolites were found. Among them, Lipids and lipid molecules accounted for the highest proportion. Whereas the liver is very closely related to lipid metabolism, we are close to understanding whether an individual's energy utilization efficiency is related to gene expression in the liver. We selected six ducks from each group of six ducks each for liver transcriptome analysis. A total of 322 differential genes were identified in the transcriptome analysis results, and 319 genes were significantly down-regulated. Among them, we found that prostaglandin endoperoxide synthase 2 (PTGS2) might be a key hub gene regulating RFI by co-occurrence network analysis. Interestingly, the differential gene PTGS2 was enriched in the arachidonic acid pathway at the same time as the differential metabolite 15-deoxy-delta12,14-prostaglandin J2 (15d-PGJ2). In addition, the results of the association analysis of differential metabolites with microorganisms also revealed a significant negative correlation between 15d-PGJ2 and Elusimicrobiota.

CONCLUSION

Based on comprehensive analysis of the research results, we speculate that the Elusimicrobiota may affect the feed utilization efficiency in ducks by regulating the expression of the PTGS2 gene.

The role of immune regulation in HBV infection and hepatocellular carcinogenesis

Hepatitis B virus (HBV) infection is a well-documented independent risk factor for developing hepatocellular carcinoma (HCC). Consequently, extensive research has focused on elucidating the mechanisms by which HBV induces hepatocarcinogenesis. The majority of studies are dedicated to understanding how HBV DNA integration into the host genome, viral RNA expression, and the resulting protein transcripts affect cellular processes and promote the malignant transformation of hepatocytes. However, considering that most acute HBV infections are curable, immune suppression potentially contributes to the critical challenges in the treatment of chronic infections. Regulatory T cells (Tregs) are crucial in immune tolerance. Understanding the interplay of Tregs within the liver microenvironment following HBV infection could offer novel therapeutic approaches for treating HBV infections and preventing HBV-related HCC. Two viewpoints to targeting Tregs in the liver microenvironment include means of reducing their inhibitory function and decreasing Treg frequency. As these strategies may disrupt the immune balance and lead to autoimmune responses, careful and comprehensive profiling of the patient's immunological status and genetic factors is required to successfully employ this promising therapeutic approach.

Single-Cell Analysis Reveals Tissue-Specific T Cell Adaptation and Clonal Distribution Across the Human Gut-Liver-Blood Axis

Understanding T cell clonal relationships and tissue-specific adaptations is crucial for deciphering human immune responses, particularly within the gut-liver axis. We performed paired single-cell RNA and T cell receptor sequencing on matched colon (epithelium, lamina propria), liver, and blood T cells from the same human donors. This approach tracked clones across sites and assessed microenvironmental impacts on T cell phenotype. While some clones were shared between blood and tissues, colonic intraepithelial lymphocytes (IELs) exhibited limited overlap with lamina propria T cells, suggesting a largely resident population. Furthermore, tissue-resident memory T cells (TRM) in the colon and liver displayed distinct transcriptional profiles. Notably, our analysis suggested that factors enriched in the liver microenvironment may influence the phenotype of colon lamina propria TRM. This integrated single-cell analysis maps T cell clonal distribution and adaptation across the gut-liver-blood axis, highlighting a potential liver role in shaping colonic immunity.

Splenic red pulp macrophages eliminate the liver-resistant Streptococcus pneumoniae from the blood circulation of mice

Invasive infections by encapsulated bacteria are the major cause of human morbidity and mortality. The liver resident macrophages, Kupffer cells, form the hepatic firewall to clear many encapsulated bacteria in the blood circulation but fail to control certain high-virulence capsule types. Here we report that the spleen is the backup immune organ to clear the liver-resistant serotypes of Streptococcus pneumoniae (pneumococcus), a leading human pathogen. Asplenic mice failed to control the growth of the liver-resistant pneumococci in the blood circulation. Immunologic and genetic analyses identified splenic red pulp (RP) macrophages as the major phagocytes for bacterial clearance. Furthermore, the plasma natural antibodies against the cell wall phosphocholine and the complement system were necessary for RP macrophage-mediated immunity. These findings have provided a conceptual framework for the innate defense against blood bacterial infections, a mechanistic explanation for the hyper-susceptibility of asplenic individuals to S. pneumoniae, and a proof of concept for developing vaccines and therapeutic antibodies against encapsulated pathogens.

Neutrophil plasticity in liver diseases

The liver has critical digestive, metabolic, and immunosurveillance roles, which get disrupted during liver diseases such as viral hepatitis, fatty liver disease, and hepatocellular carcinoma. While previous research on the pathological development of these diseases has focused on liver-resident immune populations, such as Kupffer cells, infiltrating immune cells responding to pathogens and disease also play crucial roles. Neutrophils are one such key population contributing to hepatic inflammation and disease progression. Belonging to the initial waves of immune response to threats, neutrophils suppress bacterial and viral spread during acute infections and have homeostasis-restoring functions, whereas during chronic insults, they display their plastic nature by responding to the inflammatory environment and develop new phenotypes alongside longer life spans. This review summarizes the diversity in neutrophil function and subpopulations present at steady state, during liver disease, and during liver cancer.

Engineered extracellular vesicles promote the repair of acute kidney injury by modulating regulatory T cells and the immune microenvironment

BACKGROUND

Acute kidney injury (AKI) is a common and severe clinical condition. However, the underlying mechanisms of AKI have not been fully elucidated, and effective treatment options remain limited. Studies have shown that immune cells play a critical role in AKI, with regulatory T cells (Tregs) being one of the most important immunosuppressive lymphocytes. Tregs proliferation can attenuate AKI, whereas depletion exacerbates kidney injury. Given that endothelial cells (ECs) are the initial cells that interact with immune cells when they invade the tissue parenchyma, ECs are closely associated with immune reactions.

METHODS AND RESULTS

In this study, P-selectin binding peptide-extracellular vesicles (PBP-EVs) that target and repair ECs are engineered. Transcriptome sequencing reveals that PBP-EVs reduce the expression of inflammatory genes in AKI mice. Using high-resolution intravital two-photon microscopy (TPM), an increased recruitment of Tregs in the kidneys of AKI Foxp3-EGFP transgenic mice following PBP-EVs treatment is observed, as well as significant Lgr5+ renal stem cell proliferation in AKI Lgr5-CreERT2; R26mTmG mice. Additionally, PBP-EVs treatment result in reduced infiltration of inflammatory cells, pathological damage and fibrosis of AKI mice. Upon depletion of Tregs in Foxp3-DTR transgenic mice, we observe diminished therapeutic effect of PBP-EVs on AKI.

CONCLUSIONS

The experimental results indicate that PBP-EVs can promote the repair and regeneration of AKI by mitigating endothelial cell damage and subsequently modulating Tregs and the immune microenvironment. These findings provide novel insights and strategies for the treatment of AKI.

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.

Bidirectional regulation of the cyclic guanosine monophosphate-adenosine monophosphate synthase-stimulator of interferon gene pathway and its impact on hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) ranks as the fourth leading cause of cancer-related deaths in China, and the treatment options are limited. The cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS) activates the stimulator of interferon gene (STING) signaling pathway as a crucial immune response pathway in the cytoplasm, which detects cytoplasmic DNA to regulate innate and adaptive immune responses. As a potential therapeutic target, cGAS-STING pathway markedly inhibits tumor cell proliferation and metastasis, with its activation being particularly relevant in HCC. However, prolonged pathway activation may lead to an immunosuppressive tumor microenvironment, which fostering the invasion or metastasis of liver tumor cells.

AIM

To investigate the dual-regulation mechanism of cGAS-STING in HCC.

METHODS

This review was conducted according to the PRISMA guidelines. The study conducted a comprehensive search for articles related to HCC on PubMed and Web of Science databases. Through rigorous screening and meticulous analysis of the retrieved literature, the research aimed to summarize and elucidate the impact of the cGAS-STING pathway on HCC tumors.

RESULTS

All authors collaboratively selected studies for inclusion, extracted data, and the initial search of online databases yielded 1445 studies. After removing duplicates, the remaining 964 records were screened. Ultimately, 55 articles met the inclusion criteria and were included in this review.

CONCLUSION

Acute inflammation can have a few inhibitory effects on cancer, while chronic inflammation generally promotes its progression. Extended cGAS-STING pathway activation will result in a suppressive tumor microenvironment.

Natural antibodies to polysaccharide capsules enable Kupffer cells to capture invading bacteria in the liver sinusoids

The interception of blood-borne bacteria in the liver defines the outcomes of invasive bacterial infections, but the mechanisms of this antibacterial immunity are not fully understood. This study shows that natural antibodies (nAbs) to capsules enable liver macrophage Kupffer cells (KCs) to rapidly capture and kill blood-borne encapsulated bacteria in mice. Affinity pulldown with serotype-10A capsular polysaccharides (CPS10A) of Streptococcus pneumoniae (Spn10A) led to the identification of CPS10A-binding nAbs in serum. The CPS10A-antibody interaction enabled KCs to capture Spn10A bacteria from the bloodstream, in part through complement receptors on KCs. The nAbs were found to recognize the β1-6-linked galactose branch of CPS10A and similar moieties of serotype-39 S. pneumoniae and serotype-K50 Klebsiella pneumoniae capsules. More importantly, the nAbs empowered KCs to capture serotype-39 S. pneumoniae and serotype-K50 K. pneumoniae in the liver. Collectively, our data have revealed a highly effective immune function of nAb against encapsulated bacteria and emphasize the concept of treating septic encapsulated bacterial diseases with monoclonal antibodies.

Physiological accumulation of lipid droplets in the newborn liver during breastfeeding is driven by TLR4 ligands

The liver plays a central role in fat storage, but little is known about physiological fat accumulation during early development. Here we investigated a transient surge in hepatic lipid droplets observed in newborn mice immediately after birth. We developed a novel model to quantify liver fat content without tissue processing. Using high-resolution microscopy assessed the spatial distribution of lipid droplets within hepatocytes. Lugol's iodine staining determined the timing weaning period, and milk deprivation experiments investigated the relationship between milk intake and fat accumulation. Lipidomic analysis revealed changes in the metabolic profile of the developing liver. Finally, we investigated the role of Toll-like receptor 4 (TLR4) signaling in fat storage using knockout mice and cell-specific deletion strategies. Newborn mice displayed a dramatic accumulation of hepatic lipid droplets within the first 12 h after birth, persisting for the initial two weeks of life. This pattern coincided with exclusive milk feeding and completely abated by the third week, aligning with weaning. Importantly, the observed fat accumulation shared characteristics with established models of pathological steatosis, suggesting potential biological relevance. Lipid droplets were primarily localized within the cytoplasm of hepatocytes. Milk deprivation experiments demonstrated that milk intake is the primary driver of this transient fat accumulation. Lipidomic analysis revealed significant changes in the metabolic profile of newborn livers compared to adults. Interestingly, several highly abundant lipids in newborns were identified as putative ligands for TLR4. Subsequent studies using TLR4-deficient mice and cell-specific deletion revealed that TLR4 signaling, particularly within hepatocytes, plays a critical role in driving fat storage within the newborn liver. Additionally, a potential collaboration between metabolic and immune systems was suggested by the observed effects of myeloid cell-specific TLR4 ablation. This study demonstrates a unique phenomenon of transient hepatic fat accumulation in newborn mice driven by milk intake and potentially regulated by TLR4 signaling, particularly within hepatocytes.

Maternal milk cell components are uptaken by infant liver macrophages via extracellular vesicle mediated transport

Milk is a multifaceted biofluid that is essential for infant nutrition and development, yet its cellular and bioactive components, particularly maternal milk cells, remain understudied. Early research on milk cells indicated that they cross the infant's intestinal barrier and accumulate within systemic organs. However, due to the absence of modern analytical techniques, these studies were limited in scope and mechanistic analysis. To overcome this knowledge gap, we have investigated the transintestinal transport of milk cells and components in pups over a 21-day period. Studies employed a mT/mG foster nursing model in which milk cells express a membrane-bound fluorophore, tdTomato. Using flow cytometry, we tracked the transport of milk cell-derived components across local and systemic tissues, including the intestines, blood, thymus, mesenteric lymph nodes, and liver. These experiments identified milk-derived fluorescent signals in intestinal epithelial and immune cells as well as liver macrophages in 7-day-old pups. However, the minute numbers of macrophages in mouse milk suggest that maternal cells are not systemically accumulating in the infant; instead, pup macrophages are consuming milk cell membrane components, such as apoptotic bodies or extracellular vesicles (EVs). Ex vivo experiments using primary macrophages support this hypothesis, showing that immune cells preferentially consumed EVs over milk cells. Together, these data suggest a more complex interplay between milk cells and the infant's immune and digestive systems than previously recognized and highlight the need for future research on the role of milk cells in infant health.

T-cell Receptor Repertoire Analysis in the Context of Transarterial Chemoembolization Synergy with Systemic Therapy for Hepatocellular Carcinoma

T-cell receptor (TCR) sequencing provides a novel platform for insight into and characterization of intricate T-cell profiles, advancing the understanding of tumor immune heterogeneity. Recently, transarterial chemoembolization (TACE) combined with systemic therapy has become the recommended regimen for advanced hepatocellular carcinoma. The regulation of the immune microenvironment after TACE and its impact on tumor progression and recurrence has been a focus of research. By examining and tracking fluctuations in the TCR repertoire following combination treatment, novel perspectives on the modulation of the tumor microenvironment post-TACE and the underlying mechanisms governing tumor progression and recurrence can be gained. Clarifying the distinctive metrics and dynamic alterations of the TCR repertoire within the context of combination therapy is imperative for understanding the mechanisms of anti-tumor immunity, assessing efficacy, exploiting novel treatments, and further advancing precision oncology in the treatment of hepatocellular carcinoma. In this review, we initially summarized the fundamental characteristics of TCR repertoire and depicted immune microenvironment remodeling after TACE. Ultimately, we illustrated the prospective applications of TCR repertoires in TACE combined with systemic therapy.

The liver's dilemma: sensing real danger in a sea of PAMPs: the (arterial) sinusoidal segment theory

The liver is susceptible to viruses and bacterial infections, tumors, and sterile tissue damage, but immunological danger recognition in the liver is highly unconventional. When analyzing innate and adaptive immunity in the organ, the valid concepts that guide danger recognition and immune response in the periphery should be put aside. In the liver, the vascular anatomy is a game changer, as about 80% of the blood that percolates the organ arrives from the hepatic portal vein, draining blood rich in molecules from the intestinal flora. This 24/7 exposure to high amounts of pathogen-associated molecular pattern (PAMPs) molecules results in hepatic immunological tolerance. In the liver, dendritic, Kupffer (KC), liver sinusoidal endothelial cells (LSECs), and even hepatocytes express PD-L1, a T lymphocyte downregulatory molecule. Most cells express Fas-L, IL-10, TGF-β, low levels of co-stimulatory molecules, lack of or have low levels of MHC-I and/or MHC-II expression. Moreover, other negative regulators such as CTLA-4, IDO-1, and prostaglandin E2 (PGE2) are regularly expressed. Then, how can real danger be discerned and recognized in this sea of PAMPs? This is an open question. Here, we hypothesize that conventional immunological danger recognition can occur in the liver but in specific and minor arterial sinusoidal segments,. Then, in the portal triad, where the hepatic artery ramificates into the stroma and carries arterial blood with no gut-derived PAMPs, there is no evolutive or environmental pressure for immunosuppressive pathways, and conventional immunological danger recognition could occur. Therefore, in arterial sinusoidal segments with no sea of PAMPs, the liver could recognize real danger and support innate and adaptive immunity.

ERG mediates the differentiation of hepatic progenitor cells towards immunosuppressive PDGFRα+ cancer-associated fibroblasts during hepatocarcinogenesis

Cancer-associated fibroblasts (CAFs) play important roles in the occurrence and development of hepatocellular carcinoma (HCC) and are a key component of the immunosuppressive microenvironment. However, the origin of CAFs has not been fully elucidated. We employed single-cell sequencing technology to identify the dynamic changes in different subsets of fibroblasts at different time points in rat primary HCC model. Inflammation-associated CAFs (Pdgfrα+ CAFs) were subsequently identified, which demonstrated a significant correlation with the survival duration of HCC patients and a dual role in the tumour microenvironment (TME). On the one hand, they secrete the chemokines CCL3 and CXCL12, which recruit macrophages to the tumour site. On the other hand, they produce TGFβ, inducing the polarization of these macrophages towards an immunosuppressive phenotype. According to the in vitro and in vivo results, hepatic progenitor cells (HPCs) can aberrantly differentiate into PDGFRα+ CAFs upon stimulation with inflammatory cytokine. This differentiation is mediated by the activation of the MAPK signaling pathway and the downstream transcription factor ERG via the TLR4 receptor. Downregulating the expression of ERG in HPCs significantly reduces the number of PDGFRα+ CAFs and the infiltration of tumour-associated macrophages in HCC, thereby suppressing hepatocarcinogenesis. Collectively, our findings elucidate the distinct biological functions of PDGFRα+ cancer-associated fibroblasts (PDGFRα+ CAFs) within the TME. These insights contribute to our understanding of the mechanisms underlying the establishment of an immunosuppressive microenvironment in HCC, paving the way for the exploration of novel immunotherapeutic strategies tailored for HCC treatment.

Laparoscopic versus open liver resection for intrahepatic cholangiocarcinoma: Stratified analysis based on tumor burden score

The role of laparoscopic liver resection (LLR) for intrahepatic cholangiocarcinoma (ICC) remains debated. This study aimed to evaluate the short- and long-term outcomes of LLR vs. open liver resection (OLR) in ICC stratified by tumor burden score (TBS). ICC patients who underwent LLR or OLR were included from a multicenter database between July 2009 and October 2022. Patients were stratified into two cohorts based on whether the TBS was > 5.3. A 1:3 propensity score matching (PSM) analysis was performed between LLR and OLR in each cohort. Cox regression analysis was used to identify prognostic factors for ICC. A total of 626 patients were included in this study, 304 and 322 patients were classified into the low- and high-TBS groups, respectively. In the low-TBS group, after PSM, LLR was associated with less blood loss, lower CCI, fewer complications and shorter hospital stay (all p < 0.05). Kaplan-Meier curves revealed that LLR had better OS (p = 0.032). Multivariate Cox regression analysis showed that surgical procedure was an independent prognostic factor for ICC (HR: 0.445; 95% CI: 0.235-0.843; p = 0.013). In the high-TBS group, after PSM, LLR were associated with reduced blood loss, lower CCI, fewer complications and shorter hospital stay (all p < 0.05), while OS (p = 0.98) and DFS (p = 0.24) were similar between the two groups. TBS is an important prognostic factor for ICC. LLR is a safe and feasible option for ICC and leads to faster postoperative recovery. LLR can offer ICC a comparable and even better long-term prognosis than OLR.

From gingiva to multiple organs in mice: The trace of Porphyromonas gingivalis via in vivo imaging

Background/purpose

Periodontitis is associated with systemic health. One of the underlying mechanisms is the translocation of periodontal pathogens, among which Porphyromonas gingivalis (Pg) is the most common. Here, we aimed to illustrate the biodistribution and dynamics of Pg from gingiva to multiple organs through blood circulation.

Materials and methods

Pg tagged by Cyanine 7 (Cy7-Pg) was injected into the gingiva of healthy and periodontitis mice. In vivo imaging system (IVIS) was applied to monitor the distribution of Cy7-Pg in multiple organs which were isolated at serial timepoints. Polymerase chain reaction (PCR) was conducted to determine the Pg DNA copies in the gingiva, blood and organs. Cy7-Pg in the gingiva and organs was also confirmed by frozen section staining. Furthermore, to figure out whether the bacteremia derived from oral-gut axis, mice received gavage of Cy7-Pg. Then the blood and organ samples were detected in the similar way as above.

Results

Intra-gingival injection induced larger amounts of Cy7-Pg accumulating in the gingiva of periodontitis mice (P < 0.05) as confirmed by above three methods. Twenty minutes after injection, Pg DNA copies in the blood of periodontitis group were 36.3-fold higher than healthy group (P < 0.05). IVIS results, combined with PCR and frozen sections, demonstrated periodontitis induced longer retention with higher amounts of Cy7-Pg in the periodontitis group. Pg was enriched more significantly in the liver for the longer duration than the kidney and pancreas.

Conclusion

Our study showed Pg, which accumulated in the gingiva, could translocate through blood circulation to multiple organs with varied duration and amounts.

RegⅢγ promotes the proliferation, and inhibits inflammation response of macrophages by Akt, STAT3 and NF-κB pathways

As an inflammatory regulator, intestinal regenerating islet-derived 3 gamma (RegⅢγ) contributes to alleviating liver injury in liver diseases and colitis. However, it is unclear whether hepatic RegⅢγ exerts a vital impact on liver regeneration (LR). In this study, the expression profile and localization of RegⅢγ in LR were demonstrated by microarray analysis, qRT-PCR and immunofluorescence staining. Then, RAW264.7 cells with RegⅢγ deficiency and overexpression were obtained by the CRISPR/Cas9 system and lentivirus infection, respectively. MTT, flow cytometry, EdU, transwell, neutral red phagocytosis, and NO assays were performed to detect the functions of RegⅢγ in RAW264.7 cell proliferation and inflammation. Finally, the regulatory mechanism of RegⅢγ was explored by co-immunoprecipitation and Western blot assays. According to our findings, RegⅢγ showed significant expression changes in Kupffer cells during LR, and RegⅢγ overexpression stimulated the viability, proliferation, phagocytosis and migration of RAW264.7 cells, whereas RegⅢγ deficiency reversed these effects. Similarly, RegⅢγ overexpression facilitated the expression of HO-1 and IL-10, while RegⅢγ deficiency promoted NO production and p-Akt, p-STAT3, p-p65 and TNF-α expression. In conclusion, RegⅢγ may facilitate LR by promoting the proliferation of macrophages and inhibiting their inflammatory response through Akt, STAT3 and NF-κB pathways in the priming stage of LR.

Pinpointing the integration of artificial intelligence in liver cancer immune microenvironment

Liver cancer remains one of the most formidable challenges in modern medicine, characterized by its high incidence and mortality rate. Emerging evidence underscores the critical roles of the immune microenvironment in tumor initiation, development, prognosis, and therapeutic responsiveness. However, the composition of the immune microenvironment of liver cancer (LC-IME) and its association with clinicopathological significance remain unelucidated. In this review, we present the recent developments related to the use of artificial intelligence (AI) for studying the immune microenvironment of liver cancer, focusing on the deciphering of complex high-throughput data. Additionally, we discussed the current challenges of data harmonization and algorithm interpretability for studying LC-IME.

Maresin1 Inhibits Ferroptosis via the Nrf2/SLC7A11/GPX4 Pathway to Protect Against Sepsis-Induced Acute Liver Injury

Purpose

Maresin 1 (MaR1) is a specialized pro-resolving mediator with anti-inflammatory properties that promotes tissue repair. This study aims to investigate the molecular involvement of MaR1 in protecting against sepsis-induced acute liver injury (SI-ALI).

Methods

In vivo, a murine SI-ALI model was established using the cecal ligation and puncture (CLP) paradigm, providing a system in which the mechanistic functions of MaR1 could be tested. These analyses were supplemented through in vitro assays in which Alpha mouse liver 12 (AML12) hepatocytes and RAW264.7 macrophages were co-cultured in a Transwell system, with lipopolysaccharide (LPS) stimulation being used to establish a sepsis model. These cells were treated with MaR1 and/or nuclear factor erythroid 2-related factor 2 (Nrf2)inhibitor, while lentiviral transduction was used to knock down Nrf2 within AML12 cells. Hepatic pathological damage was assessed through hematoxylin and eosin staining. Lipid peroxidation-related analyses were conducted through the use of thiobarbituric acid, ferrous ions, glutathione, and appropriate fluorescent probes for reactive oxygen species detection. Liver enzymes and inflammatory mediators were quantified using appropriate Enzyme-Linked Immunosorbent Assays (ELISAs). Protein concentrations were evaluated via Western blot analysis.

Results

The presence of ferroptosis in SI-ALI. MaR1 was found to proficiently suppress ferroptosis in SI-ALI. Mechanistically, MaR1 enhanced Nrf2 expression in AML12 hepatocytes, while the Nrf2 inhibitor ML-385 or Nrf2 siRNA mitigated MaR1's regulatory influence on ferroptosis. Meanwhile, the expressions of the downstream genes solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) diminished, suggesting that MaR1 has a protective function via activating the Nrf2/SLC7A11/GPX4 pathway to mitigate ferroptosis in septic liver injury.

Conclusion

The results indicate that MaR1 mitigates SI-ALI via stimulating the Nrf2/SLC7A11/GPX4 pathway to suppress ferroptosis. Moreover, it offers significant potential as a new agent for the prevention of SI-ALI.

Liver Cancer Neuroscience: Regulating Liver Tumors via Selective Hepatic Vagotomy

Both the prevalence and mortality of liver cancers continue to rise. Early surgical interventions, including liver transplantation or resection, remain the only curative treatment. Nerves in the periphery influence tumor growth within visceral organs. Emerging cancer neuroscience efforts linked parasympathetic vagus nerves with tumor pathology, underscoring the value of vagal nerve denervation methods within cancer mouse models. Here, we describe a selective hepatic vagotomy that largely maintains non-liver parasympathetic innervation in mice. To address vagal interactions in hepatic tumor pathology, we provide an adapted methodology utilizing an established liver metastatic model. We anticipate that this methodology will expand the burgeoning field of cancer neuroscience, enabling the study of the neuroimmune, neurometabolic, and/or nerve-microbiota interactions shaping liver cancer progression and treatment.

Hepatic immune regulation and sex disparities

Chronic liver disease is a major cause of morbidity and mortality worldwide. Epidemiology, clinical phenotype and response to therapies for gastrointestinal and liver diseases are commonly different between women and men due to sex-specific hormonal, genetic and immune-related factors. The hepatic immune system has unique regulatory functions that promote the induction of intrahepatic tolerance, which is key for maintaining liver health and homeostasis. In liver diseases, hepatic immune alterations are increasingly recognized as a main cofactor responsible for the development and progression of chronic liver injury and fibrosis. In this Review, we discuss the basic mechanisms of sex disparity in hepatic immune regulation and how these mechanisms influence and modify the development of autoimmune liver diseases, genetic liver diseases, portal hypertension and inflammation in chronic liver disease. Alterations in gut microbiota and their crosstalk with the hepatic immune system might affect the progression of liver disease in a sex-specific manner, creating potential opportunities for novel diagnostic and therapeutic approaches to be evaluated in clinical trials. Finally, we identify and propose areas for future basic, translational and clinical research that will advance our understanding of sex disparities in hepatic immunity and liver disease.

Capn3b-deficient zebrafish model reveals a key role of autoimmune response in LGMDR1

Mutations in calcium-dependent papain-like protease CALPAIN3 (CAPN3) cause Limb-Girdle Muscular Dystrophy Recessive Type 1 (LGMDR1), the most common limb-girdle muscular dystrophy in humans. In addition to progressive muscle weakness, persistent inflammatory infiltration is also a feature of LGMDR1. Despite the underlying mechanism remaining poorly understood, we consider that it may relate to the newly defined role of CAPN3/Capn3b in the nucleolus. Here, we report that the loss of function of zebrafish capn3b, the counterpart of human CAPN3, induces an autoimmune response akin to that in LGMDR1 patients. capn3b mutant larvae are more susceptible to Listeria monocytogenes injection, characterized by recruiting more macrophages. Under germ-free conditions, transcriptome analysis of the capn3b mutant muscle reveals a significant upregulation of the chemokine-production-related genes. Coincidently, more neutrophils are recruited to the injury site imposed by either muscle stabbing or tail fin amputation. Nucleolar proteomic analysis and enzymatic assays reveal NKAP, an activating factor of the NF-κB pathway, to be a target of CAPN3. We conclude that the accumulation of Nkap and other factors in the capn3b mutant may be involved in the over-activation of innate immunity. Our studies indicate that the zebrafish capn3b mutant is a powerful model for studying the immunity-related progression of human LGMDR1.

Klebsiella pneumoniae capsular polysaccharide: Mechanism in regulation of synthesis, virulence, and pathogenicity

Hypervirulent Klebsiella pneumoniae exhibits strong pathogenicity and can cause severe invasive infections but is historically recognized as antibiotic-susceptible. In recent years, the escalating global prevalence of antibiotic-resistant hypervirulent K. pneumoniae has raised substantial concerns and created an urgent demand for effective treatment options. Capsular polysaccharide (CPS) is one of the main virulence determinants contributing to the hypervirulent phenotype. The structure of CPS varies widely among strains, and both the structure and composition of CPS can influence the virulence of K. pneumoniae. CPS possesses various immune evasion mechanisms that promote the survival of K. pneumoniae, as well as its colonization and dissemination. Given the proven viability of therapies that target the capsule, improving our understanding of the CPS structure is critical to effectively directing treatment strategies. In this review, the structure and typing of CPS are addressed as well as genes related to synthesis and regulation, relationships with virulence, and pathogenic mechanisms. We aim to provide a reference for research on the pathogenesis of K. pneumoniae.

Application of nanotechnology in the treatment of hepatocellular carcinoma

Hepatocellular carcinoma is the predominant histologic variant of hepatic malignancy and has become a major challenge to global health. The increasing incidence and mortality of hepatocellular carcinoma has created an urgent need for effective prevention, diagnosis, and treatment strategies. This is despite the impressive results of multiple treatments in the clinic. However, the unique tumor immunosuppressive microenvironment of hepatocellular carcinoma increases the difficulty of treatment and immune tolerance. In recent years, the application of nanoparticles in the treatment of hepatocellular carcinoma has brought new hope for tumor patients. Nano agents target tumor-associated fibroblasts, regulatory T cells, myeloid suppressor cells, tumor-associated macrophages, tumor-associated neutrophils, and immature dendritic cells, reversed the immunosuppressive microenvironment of hepatocellular carcinoma. In addition, he purpose of this review is to summarize the advantages of nanotechnology in guiding surgical excision, local ablation, TACE, standard chemotherapy, and immunotherapy, application of nano-vaccines has also continuously enriched the treatment of liver cancer. This study aims to investigate the potential applications of nanotechnology in the management of hepatocellular carcinoma, with the ultimate goal of enhancing therapeutic outcomes and improving the prognosis for patients affected by this malignancy.

The neonatal liver hosts a spontaneously occurring neutrophil population, exhibiting distinct spatial and functional characteristics from adults

The elusive nature of the liver immune system in newborns remains an important challenge, casting a shadow over our understanding of how to effectively treat and prevent diseases in children. Therefore, deeper exploration into the intricacies of neonatal immunology might be crucial for improved pediatric healthcare. Using liver intravital microscopy, we unveiled a significant population of granulocytes in the hepatic parenchyma of fetuses and newborns. Utilizing high-dimensional immunophenotyping, we showed dynamic alterations predominantly in granulocytes during neonatal development. Liver intravital microscopy from birth through adulthood captures real-time dynamics, showing a substantial presence of Ly6G+ cells that persisted significantly up to 2 wk of age. Using time-of flight mass cytometry, we characterized neonatal Ly6G+ cells as neutrophils, confirmed by morphology and immunohistochemistry. Surprisingly, the embryonic liver hosts a distinct population of neutrophils established as early as the second gestational week, challenging conventional notions about their origin. Additionally, we observed that embryonic neutrophils occupy preferentially the extravascular space, indicating their early establishment within the liver. Hepatic neutrophils in embryos and neonates form unique cell clusters, persisting during the initial days of life, while reduced migratory capabilities in neonates are observed, potentially compensating with increased reactive oxygen species release in response to stimuli. Finally, in vivo imaging of acute neutrophil behavior in a newborn mouse, subjected to focal liver necrosis, unveils that neonatal neutrophils exhibit a reduced migratory response. The study provides unprecedented insights into the intricate interplay of neutrophils within the liver, shedding light on their functional and dynamic characteristics during development.

Tryptophan Metabolites in the Progression of Liver Diseases

The aim of this study was to investigate the levels of various tryptophan metabolites in patients with alcoholic liver disease (ALD) and metabolic-associated fatty liver disease (MAFLD) at different stages of the disease. The present study included 44 patients diagnosed with MAFLD, 40 patients diagnosed with ALD, and 14 healthy individuals in the control group. The levels of tryptophan and its 16 metabolites (3-OH anthranilic acid, 5-hydroxytryptophan, 5-methoxytryptamine, 6-hydroxymelatonin, indole-3-acetic acid, indole-3-butyric, indole-3-carboxaldehyde, indole-3-lactic acid, indole-3-propionic acid, kynurenic acid, kynurenine, melatonin, quinolinic acid, serotonin, tryptamine, and xanthurenic acid) in the serum were determined via high-performance liquid chromatography and tandem mass spectrometry. In patients with cirrhosis resulting from MAFLD and ALD, there are significant divergent changes in the serotonin and kynurenine pathways of tryptophan catabolism as the disease progresses. All patients with cirrhosis showed a decrease in serotonin levels (MAFLDp = 0.038; ALDp < 0.001) and an increase in kynurenine levels (MAFLDp = 0.032; ALDp = 0.010). A negative correlation has been established between serotonin levels and the FIB-4 index (p < 0.001). The decrease in serotonin pathway metabolites was associated with manifestations of portal hypertension (p = 0.026), the development of hepatocellular insufficiency (p = 0.008) (hypoalbuminemia; hypocoagulation), and jaundice (p < 0.001), while changes in the kynurenine pathway metabolite xanthurenic acid were associated with the development of hepatic encephalopathy (p = 0.044). Depending on the etiological factors of cirrhosis, disturbances in the metabolic profile may be involved in various pathogenetic pathways.

MRTO4 acts as an independent prognostic and immunological biomarker and is correlated with tumor microenvironment in hepatocellular carcinoma

Liver cancer is a malignant tumor found worldwide. mRNA turnover 4 homolog (MRTO4) is highly expressed in hepatocellular carcinoma (HCC) tissues, and we explored its relationship with HCC. All cancer data were downloaded from the Cancer Genome Atlas (TCGA), the Cancer Immune Atlas (TCIA), and the Human Protein Atlas (THPA). Stromal scores, immune scores, and ESTIMATE scores were calculated by "ESTIMATE" R package. Single sample gene set enrichment analysis and CIBERSORT were used to evaluate the immune status and infiltration of cancer tissues. pRRophetic R package was used to predict the half-maximal inhibitory concentration (IC50) of different drugs in each sample. MRTO4 overexpression was associated with poor prognosis in HCC, and positively correlated with the stage and grade of HCC patients. The average immunophenoscore (IPS) of the low MRTO4 group was significantly higher than that of the high MRTO4 group. Tumor microenvironment (TME) scores were significantly higher in the low MRTO4 group than in the high MRTO4 group in HCC. MRTO4 expression was positively correlated with tumor mutation burden (TMB) and was positively correlated with most immune checkpoint gene expressions in HCC. Drug sensitivity analysis showed significantly higher IC50 values for 5-fluorouracil, gemcitabine, and sorafenib in patients with low MRTO4 expression than in those with high MRTO4 expression. MRTO4 acts as an independent prognostic and immunological biomarker and is correlated with clinical stage, tumor grade, and drug sensitivity in HCC. It may serve as a putative therapeutic target and potential biomarker for prognosis of HCC.

Impact of liver metastasis on immunotherapy in gastric carcinoma

The editorial discusses the impact of liver metastasis on immunotherapy efficacy in gastric cancer (GC) patients. Liver metastasis can hinder the effectiveness of immunotherapy by altering the immune microenvironment, leading to systemic loss of T-cells and reduced treatment response. Studies suggest that liver metastases serve as a negative baseline factor for immunotherapy efficacy, resulting in poorer progression-free survival and objective response rates. Strategies such as liver-mediated radiotherapy may help improve treatment outcomes by reshaping the liver's immune microenvironment and reducing T-cell depletion. Understanding the complex interplay between liver metastasis and immunotherapy response is crucial for optimising patient care in GC.

IRG1/Itaconate inhibits proliferation and promotes apoptosis of CD69+CD103+CD8+ tissue-resident memory T cells in autoimmune hepatitis by regulating the JAK3/STAT3/P53 signalling pathway

To investigate the protective role of immune response gene 1 (IRG1) and exogenous itaconate in autoimmune hepatitis (AIH) and elucidate the underlying mechanisms. Wild-type and IRG1-/- AIH mouse models were established, and samples of liver tissue and ocular blood were collected from each group of mice to assess the effects of IRG1/itaconate on the expression of pro- and anti-inflammatory cytokines. The levels of liver enzymes and related inflammatory factors were determined using enzyme-linked immunosorbent assay and real-time quantitative polymerase chain reaction (PCR). Liver histomorphology was detected through hematoxylin and eosin staining and then scored for liver injury, and the infiltration levels of tissue-resident memory T (TRM) cells and related molecules in the liver tissue were detected through immunofluorescence staining in vitro. RNA sequencing and gene enrichment analysis were conducted to identify the corresponding molecules and pathways, and lentiviral transfection was used to generate TRM cell lines with IRG1, Jak3, Stat3, and p53 knockdown. Real-time quantitative PCR and western blot were performed to detect the expression levels of relevant mRNAs and proteins in the liver tissue and cells. The percentage of apoptotic cells was determined using flow cytometry. IRG1/itaconate effectively reduced the release of pro-inflammatory cytokines and the pathological damage to liver tissue, thereby maintaining normal liver function. At the same time, IRG1/itaconate inhibited the JAK3/STAT3 signaling pathway, regulated the expression of related downstream proteins, and inhibited the proliferation and promoted the apoptosis of CD69+CD103+CD8+ TRM cells. For the first time, P53 was found to act as a downstream molecule of the JAK3/STAT3 pathway and was regulated by IRG1/itaconate to promote the apoptosis of CD8+ TRM cells. IRG1/itaconate can alleviate concanavalin A-induced autoimmune hepatitis in mice by inhibiting the proliferation and promoting the apoptosis of CD69+CD103+CD8+ TRM cells via the JAK3/STAT3/P53 pathway.

Infections in decompensated cirrhosis: Pathophysiology, management, and research agenda

Bacterial infections in patients with cirrhosis lead to a 4-fold increase in mortality. Immune dysfunction in cirrhosis further increases the risk of bacterial infections, in addition to alterations in the gut microbiome, which increase the risk of pathogenic bacteria. High rates of empiric antibiotic use contribute to increased incidence of multidrug-resistant organisms and further increases in mortality. Despite continous advances in the field, major unknowns regarding interactions between the immune system and the gut microbiome and strategies to reduce infection risk and improve mortality deserve further investigation. Here, we highlight the unknowns in these major research areas and make a proposal for a research agenda to move toward improving disease progression and outcomes in patients with cirrhosis and infections.

TMEM16F Expressed in Kupffer Cells Regulates Liver Inflammation and Metabolism to Protect Against Listeria Monocytogenes

Infection by bacteria leads to tissue damage and inflammation, which need to be tightly controlled by host mechanisms to avoid deleterious consequences. It is previously reported that TMEM16F, a calcium-activated lipid scramblase expressed in various immune cell types including T cells and neutrophils, is critical for the control of infection by bacterium Listeria monocytogenes (Lm) in vivo. This function correlated with the capacity of TMEM16F to repair the plasma membrane (PM) damage induced in T cells in vitro, by the Lm toxin listeriolysin O (LLO). However, whether the protective effect of TMEM16F on Lm infection in vivo is mediated by an impact in T cells, or in other cell types, is not determined. Herein, the immune cell types and mechanisms implicated in the protective effect of TMEM16F against Lm in vivo are elucidated. Cellular protective effects of TMEM16F correlated with its capacity of lipid scrambling and augment PM fluidity. Using cell type-specific TMEM16F-deficient mice, the indication is obtained that TMEM16F expressed in liver Kupffer cells (KCs), but not in T cells or B cells, is key for protection against Listeria in vivo. In the absence of TMEM16F, Listeria induced PM rupture and fragmentation of KCs in vivo. KC death associated with greater liver damage, inflammatory changes, and dysregulated liver metabolism. Overall, the results uncovered that TMEM16F expressed in Kupffer cells is crucial to protect the host against Listeria infection. This influence is associated with the capacity of Kupffer cell-expressed TMEM16F to prevent excessive inflammation and abnormal liver metabolism.

Sorafenib plus memory-like natural killer cell immunochemotherapy boosts treatment response in liver cancer

BACKGROUND

Heterogeneity of hepatocellular carcinoma (HCC) presents significant challenges for therapeutic strategies and necessitates combinatorial treatment approaches to counteract suppressive behavior of tumor microenvironment and achieve improved outcomes. Here, we employed cytokines to induce memory-like behavior in natural killer (NK) cells, thereby enhancing their cytotoxicity against HCC. Additionally, we evaluated the potential benefits of combining sorafenib with this newly developed memory-like NK cell (pNK) immunochemotherapy in a preclinical model.

METHODS

HCC tumors were grown in SD rats using subcapsular implantation. Interleukin 12/18 cytokines were supplemented to NK cells to enhance cytotoxicity through memory activation. Tumors were diagnosed using MRI, and animals were randomly assigned to control, pNK immunotherapy, sorafenib chemotherapy, or combination therapy groups. NK cells were delivered locally via the gastrointestinal tract, while sorafenib was administered systemically. Therapeutic responses were monitored with weekly multi-parametric MRI scans over three weeks. Afterward, tumor tissues were harvested for histopathological analysis. Structural and functional changes in tumors were evaluated by analyzing MRI and histopathology data using ANOVA and pairwise T-test analyses.

RESULTS

The tumors were allowed to grow for six days post-cell implantation before treatment commenced. At baseline, tumor diameter averaged 5.27 mm without significant difference between groups (p = 0.16). Both sorafenib and combination therapy imposed greater burden on tumor dimensions compared to immunotherapy alone in the first week. By the second week of treatment, combination therapy had markedly expanded its therapeutic efficacy, resulting in the most significant tumor regression observed (6.05 ± 1.99 vs. 13.99 ± 8.01 mm). Histological analysis demonstrated significantly improved cell destruction in the tumor microenvironment associated with combination treatment (63.79%). Interestingly, we observed fewer viable tumor regions in the sorafenib group (38.9%) compared to the immunotherapy group (45.6%). Notably, there was a significantly higher presence of NK cells in the tumor microenvironment with combination therapy (34.79%) compared to other groups (ranging from 2.21 to 26.50%). Although the tumor sizes in the monotherapy groups were similar, histological analysis revealed a stronger response in pNK cell immunotherapy group compared to the sorafenib group.

CONCLUSIONS

Experimental results indicated that combination therapy significantly enhanced treatment response, resulting in substantial tumor growth reduction in alignment with histological analysis.

Mechanism of mesenchymal stem cells in liver regeneration: Insights and future directions

Mesenchymal stem cells (MSCs) are a prevalent source for stem cell therapy and play a crucial role in modulating both innate and adaptive immune responses. Non-alcoholic fatty liver disease (NAFLD) is characterized by the accumulation of triglycerides in liver cells and involves immune system activation, leading to histological changes, tissue damage, and clinical symptoms. A recent publication by Jiang et al, highlighted the potential of MSCs to mitigate in NAFLD progression by targeting various molecular pathways, including glycolipid metabolism, inflammation, oxidative stress, endoplasmic reticulum stress, and fibrosis. In this editorial, we comment on their research and discuss the efficacy of MSC therapy in treating NAFLD.

Kupffer Cells and Hepatocytes: A Key Relation in the Context of Canine Leishmaniasis

Human zoonotic visceral leishmaniasis (ZVL) and canine leishmaniasis (CanL) constitute a major public and veterinary health concern and are both caused by the infection with the protozoan parasite Leishmania infantum. One of the main target organs in CanL is the liver. This complex organ, composed of various highly specialized cell types, has garnered significant attention from the scientific community as a crucial player in innate immune functions. In the context of CanL, liver infection by parasites and the host immune response generated strongly influence the disease outcome. Thus, taking advantage of a co-culture system involving canine hepatocytes and L. infantum-infected autologous Kupffer cells (KCs), allowing cell-to-cell interaction, the current report aims to shed light on the hepatocyte-KCs immune interaction. The co-culture of infected KCs with hepatocytes revealed a vital role of these cells in the activation of a local immune response against L. infantum parasites. Although KCs alone can be immunologically silenced by L. infantum infection, the cell-to-cell interaction with hepatocytes in co-culture can lead to local immune activation. In co-culture it was observed gene expression increased the number of innate immune receptors, specifically cell membrane TLR2 and cytoplasmatic NOD1 along with high TNF-α generation. Altogether, these results suggest that the immune response generated in co-culture could induce the recruitment of other circulating cells to contain and contribute to the resolution of the infection in the liver. This work also enhances our understanding of the liver as a vital organ in innate immunity within the context of CanL.

Spatial genomics: mapping human steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD, formerly known as non-alcoholic fatty liver disease) is a leading cause of chronic liver disease worldwide. MASLD can progress to metabolic dysfunction-associated steatohepatitis (MASH, formerly known as non-alcoholic steatohepatitis) with subsequent liver cirrhosis and hepatocellular carcinoma formation. The advent of current technologies such as single-cell and single-nuclei RNA sequencing have transformed our understanding of the liver in homeostasis and disease. The next frontier is contextualizing this single-cell information in its native spatial orientation. This understanding will markedly accelerate discovery science in hepatology, resulting in a further step-change in our knowledge of liver biology and pathobiology. In this Review, we discuss up-to-date knowledge of MASLD development and progression and how the burgeoning field of spatial genomics is driving exciting new developments in our understanding of human liver disease pathogenesis and therapeutic target identification.

Immune signature and therapeutic approach of natural killer cell in chronic liver disease and hepatocellular carcinoma

Natural killer (NK) cells are one of the key members of innate immunity that predominantly reside in the liver, potentiating immune responses against viral infections or malignant tumors. It has been reported that changes in cell numbers and function of NK cells are associated with the development and progression of chronic liver diseases (CLDs) including non-alcoholic fatty liver disease, alcoholic liver disease, and chronic viral hepatitis. Also, it is known that the crosstalk between NK cells and hepatic stellate cells plays an important role in liver fibrosis and cirrhosis. In particular, the impaired functions of NK cells observed in CLDs consequently contribute to occurrence and progression of hepatocellular carcinoma (HCC). Chronic infections by hepatitis B or C viruses counteract the anti-tumor immunity of the host by producing the sheddases. Soluble major histocompatibility complex class I polypeptide-related sequence A (sMICA), released from the cell surfaces by sheddases, disrupts the interaction and affects the function of NK cells. Recently, the MICA/B-NK stimulatory receptor NK group 2 member D (NKG2D) axis has been extensively studied in HCC. HCC patients with low membrane-bound MICA or high sMICA concentration have been associated with poor prognosis. Therefore, reversing the sMICA-mediated downregulation of NKG2D has been proposed as an attractive strategy to enhance both innate and adaptive immune responses against HCC. This review aims to summarize recent studies on NK cell immune signatures and its roles in CLD and hepatocellular carcinogenesis and discusses the therapeutic approaches of MICA/B-NKG2D-based or NK cell-based immunotherapy for HCC.

A Narrative Review: Immunometabolic Interactions of Host-Gut Microbiota and Botanical Active Ingredients in Gastrointestinal Cancers

The gastrointestinal tract is where the majority of gut microbiota settles; therefore, the composition of the gut microbiota and the changes in metabolites, as well as their modulatory effects on the immune system, have a very important impact on the development of gastrointestinal diseases. The purpose of this article was to review the role of the gut microbiota in the host environment and immunometabolic system and to summarize the beneficial effects of botanical active ingredients on gastrointestinal cancer, so as to provide prospective insights for the prevention and treatment of gastrointestinal diseases. A literature search was performed on the PubMed database with the keywords "gastrointestinal cancer", "gut microbiota", "immunometabolism", "SCFAs", "bile acids", "polyamines", "tryptophan", "bacteriocins", "immune cells", "energy metabolism", "polyphenols", "polysaccharides", "alkaloids", and "triterpenes". The changes in the composition of the gut microbiota influenced gastrointestinal disorders, whereas their metabolites, such as SCFAs, bacteriocins, and botanical metabolites, could impede gastrointestinal cancers and polyamine-, tryptophan-, and bile acid-induced carcinogenic mechanisms. GPRCs, HDACs, FXRs, and AHRs were important receptor signals for the gut microbial metabolites in influencing the development of gastrointestinal cancer. Botanical active ingredients exerted positive effects on gastrointestinal cancer by influencing the composition of gut microbes and modulating immune metabolism. Gastrointestinal cancer could be ameliorated by altering the gut microbial environment, administering botanical active ingredients for treatment, and stimulating or blocking the immune metabolism signaling molecules. Despite extensive and growing research on the microbiota, it appeared to represent more of an indicator of the gut health status associated with adequate fiber intake than an autonomous causative factor in the prevention of gastrointestinal diseases. This study detailed the pathogenesis of gastrointestinal cancers and the botanical active ingredients used for their treatment in the hope of providing inspiration for research into simpler, safer, and more effective treatment pathways or therapeutic agents in the field.

Host-pathogen interactions in the Plasmodium-infected mouse liver at spatial and single-cell resolution

Upon infecting its vertebrate host, the malaria parasite initially invades the liver where it undergoes massive replication, whilst remaining clinically silent. The coordination of host responses across the complex liver tissue during malaria infection remains unexplored. Here, we perform spatial transcriptomics in combination with single-nuclei RNA sequencing over multiple time points to delineate host-pathogen interactions across Plasmodium berghei-infected liver tissues. Our data reveals significant changes in spatial gene expression in the malaria-infected tissues. These include changes related to lipid metabolism in the proximity to sites of Plasmodium infection, distinct inflammation programs between lobular zones, and regions with enrichment of different inflammatory cells, which we term 'inflammatory hotspots'. We also observe significant upregulation of genes involved in inflammation in the control liver tissues of mice injected with mosquito salivary gland components. However, this response is considerably delayed compared to that observed in P. berghei-infected mice. Our study establishes a benchmark for investigating transcriptome changes during host-parasite interactions in tissues, it provides informative insights regarding in vivo study design linked to infection and offers a useful tool for the discovery and validation of de novo intervention strategies aimed at malaria liver stage infection.

Exploring the role of the immune microenvironment in hepatocellular carcinoma: Implications for immunotherapy and drug resistance

Hepatocellular carcinoma (HCC), the most common type of liver tumor, is a leading cause of cancer-related deaths, and the incidence of liver cancer is still increasing worldwide. Curative hepatectomy or liver transplantation is only indicated for a small population of patients with early-stage HCC. However, most patients with HCC are not candidates for radical resection due to disease progression, leading to the choice of the conventional tyrosine kinase inhibitor drug sorafenib as first-line treatment. In the past few years, immunotherapy, mainly immune checkpoint inhibitors (ICIs), has revolutionized the clinical strategy for HCC. Combination therapy with ICIs has proven more effective than sorafenib, and clinical trials have been conducted to apply these therapies to patients. Despite significant progress in immunotherapy, the molecular mechanisms behind it remain unclear, and immune resistance is often challenging to overcome. Several studies have pointed out that the complex intercellular communication network in the immune microenvironment of HCC regulates tumor escape and drug resistance to immune response. This underscores the urgent need to analyze the immune microenvironment of HCC. This review describes the immunosuppressive cell populations in the immune microenvironment of HCC, as well as the related clinical trials, aiming to provide insights for the next generation of precision immunotherapy.

Crosstalk in extrahepatic and hepatic system in NAFLD/NASH

Non-alcoholic fatty liver disease (NAFLD) has emerged as the most prevalent chronic liver disease globally. Non-alcoholic steatohepatitis (NASH) represents an extremely progressive form of NAFLD, which, without timely intervention, may progress to cirrhosis or hepatocellular carcinoma. Presently, a definitive comprehension of the pathogenesis of NAFLD/NASH eludes us, and pharmacological interventions targeting NASH specifically remain constrained. The aetiology of NAFLD encompasses a myriad of external factors including environmental influences, dietary habits and gender disparities. More significantly, inter-organ and cellular interactions within the human body play a role in the development or regression of the disease. In this review, we categorize the influences affecting NAFLD both intra- and extrahepatically, elaborating meticulously on the mechanisms governing the onset and progression of NAFLD/NASH. This exploration delves into progress in aetiology and promising therapeutic targets. As a metabolic disorder, the development of NAFLD involves complexities related to nutrient metabolism, liver-gut axis interactions and insulin resistance, among other regulatory functions of extraneous organs. It further encompasses intra-hepatic interactions among hepatic cells, Kupffer cells (KCs) and hepatic stellate cells (HSCs). A comprehensive understanding of the pathogenesis of NAFLD/NASH from a macroscopic standpoint is instrumental in the formulation of future therapies for NASH.

Dissecting Acute Drug-Induced Hepatotoxicity and Therapeutic Responses of Steatotic Liver Disease Using Primary Mouse Liver and Blood Cells in a Liver-On-A-Chip Model

Metabolic dysfunction-associated steatotic liver disease (MASLD) is hallmarked by hepatic steatosis, cell injury, inflammation, and fibrosis. This study elaborates on a multicellular biochip-based liver sinusoid model to mimic MASLD pathomechanisms and investigate the therapeutic effects of drug candidates lanifibranor and resmetirom. Mouse liver primary hepatocytes, hepatic stellate cells, Kupffer cells, and endothelial cells are seeded in a dual-chamber biocompatible liver-on-a-chip (LoC). The LoC is then perfused with circulating immune cells (CICs). Acetaminophen (APAP) and free fatty acids (FFAs) treatment recapitulate acute drug-induced liver injury and MASLD, respectively. As a benchmark for the LoC, multiplex immunofluorescence on livers from APAP-injected and dietary MASLD-induced mice reveals characteristic changes on parenchymal and immune cell populations. APAP exposure induces cell death in the LoC, and increased inflammatory cytokine levels in the circulating perfusate. Under FFA stimulation, lipid accumulation, cellular damage, inflammatory secretome, and fibrogenesis are increased in the LoC, reflecting MASLD. Both injury conditions potentiate CIC migration from the perfusate to the LoC cellular layers. Lanifibranor prevents the onset of inflammation, while resmetirom decreases lipid accumulation in hepatocytes and increases the generation of FFA metabolites in the LoC. This study demonstrates the LoC potential for functional and molecular evaluation of liver disease drug candidates.

Systemic mechanisms of necrotic cell debris clearance

Necrosis is an overarching term that describes cell death modalities caused by (extreme) adverse conditions in which cells lose structural integrity. A guaranteed consequence of necrosis is the production of necrotic cell remnants, or debris. Necrotic cell debris is a strong trigger of inflammation, and although inflammatory responses are required for tissue healing, necrotic debris may lead to uncontrolled immune responses and collateral damage. Besides local phagocytosis by recruited leukocytes, there is accumulating evidence that extracellular mechanisms are also involved in necrotic debris clearance. In this review, we focused on systemic clearance mechanisms present in the bloodstream and vasculature that often cooperate to drive the clearance of cell debris. We reviewed the contribution and cooperation of extracellular DNases, the actin-scavenger system, the fibrinolytic system and reticuloendothelial cells in performing clearance of necrotic debris. Moreover, associations of the (mis)functioning of these clearance systems with a variety of diseases were provided, illustrating the importance of the mechanisms of clearance of dead cells in the organism.

Immune Response and Risk of Decompensation following SARS-CoV-2 Infection in Outpatients with Advanced Chronic Liver Disease

Advanced chronic liver disease (ACLD) is associated with a wide spectrum of immune dysfunction. The clinical impact of SARS-CoV-2 on the development of decompensation and immune response in unvaccinated outpatients has not as yet been clearly defined. This study aimed to evaluate the clinical and immunological impact of SARS-CoV-2 on outpatients with ACLD. This is an observational case-control study, in which ACLD outpatients were included prospectively and consecutively and classified into two groups: SARS-CoV-2 infected and non-infected. Patients' baseline characteristics and infection data were collected and analyzed. Immunoglobulin G (IgG) levels against Spike 1 were evaluated. The primary endpoint was risk of liver decompensation during follow-up, assessed after propensity score matching and adjusted by Cox regression. Between October 2020 and July 2021, ACLD outpatients (n = 580) were identified, and 174 patients with clinical follow-up were included. SARS-CoV-2 infection incidence was 7.6% (n = 44). Risk of liver decompensation was significantly higher after infection (HR = 2.43 [1.01-5.86], p = 0.048) vs. non-infection. The time of IgG evaluation was similar in all patients (n = 74); IgG concentrations were significantly higher in compensated vs. decompensated patients (1.02 ± 0.35 pg/mL vs. 0.34 ± 0.16 pg/mL, p < 0.0001) and correlated with hemoglobin levels. The dysregulation of the innate immune response in patients with decompensated liver disease increased the risk of further decompensation following SARS-CoV-2, mainly due to a worsening of ascites.