Liver homeostasis is coordinated by crosstalk between resident and infiltrating inflammatory cells. Liver disease creates a dynamic inflammatory microenvironment characterized by aberrant metabolism and continuous hepatic regeneration, making it an important risk factor for hepatocellular carcinoma (HCC) as well as liver failure. Recent studies have revealed a critical heterogeneous population of myeloid-derived suppressor cells (MDSCs), which influence liver disease progression and malignancy by dynamically regulating the immune microenvironment. MDSCs play an important role in preventing excessive immune responses in the liver. However, MDSCs are also associated with the promotion of liver injury and liver cancer progression. The plasticity of MDSCs in liver disease is a unique challenge for therapeutic intervention strategies and requires a deeper understanding of the underlying mechanisms. Here, we review the role of MDSCs in the establishment and progression of liver disease and highlight the evidence for MDSCs as a priority target for current and future therapeutic strategies. We explore the fate of MDSCs from hepatitis to liver cancer, providing recent insights into potential targets for clinical intervention.

The mucosal immune system plays a critical role in defending the body against external pathogens and preserving homeostasis. The polymeric immunoglobulin receptor (PIGR) is a critical component of this system, responsible for facilitating the transport and secretion of soluble polymeric immunoglobulins across epithelial cells, thereby contributing to immune defense. In zebrafish, a pIgR-like (pIgRL) family exists, among which pIgRL4.2 is highly expressed in multiple immune organs, suggesting its potential role in immunity. In this study, spring viremia of carp virus (SVCV) infection significantly downregulates pIgRL4.2 expression. Conversely, overexpression of pIgRL4.2 in EPC cells markedly delays SVCV-induced cytopathic effects and effectively suppresses SVCV replication. Additionally, overexpression of pIgRL4.2 enhances IFN activation induced by both poly(I:C) treatment and SVCV infection. Furthermore, CRISPR/Cas9 was used to generate pIgRL4.2-null zebrafish, and disruption of pIgRL4.2 in zebrafish has been demonstrated to result in a reduction in survival rates following SVCV challenge. This is accompanied by a consistent downregulation of antiviral responsive genes, concomitant with an increase in SVCV replication in pIgRL4.2-deficient zebrafish. Therefore, this study demonstrates that pIgRL4.2 inhibits viral replication by positively regulating the IFN signaling pathway.

Genetic predisposition is a necessary but not sufficient requirement for the development of a pathological immune response in systemic lupus erythematosus (SLE). Various environmental factors and nutrition in particular also play a key role in the pathogenesis of SLE. In the present study, we evaluated the effect of a specific diet containing additional amounts of methyl donors on the development of pathological changes in the liver of lupus-prone MRL/lpr mice. The results showed that long-term administration of the diet reduced the level of inflammation and the number of inflammatory cells in the liver of the treated mice compared to the control group. These data point to methyl-containing micronutrients as a potential immunomodulatory tool and suggest the application of a methyl-supplemented diet as a novel approach to manipulate the course of liver disease in SLE.

Lampranthus glaucus and Lampranthus glaucoides are only reported to have significant cytotoxic activity against certain cancer cell lines with phytochemical investigation of their petroleum ether and the ethyl acetate extracts. Further investigation was suggested concerning their hepatoprotective activity and relating it to the metabolic profile of their defatted methanol extracts using LC-ESI/MS analysis. Hepatoprotective activity was evaluated through assessment of three liver parameters as well as liver histopathological examination in thioacetamide-induced hepatotoxicity model. Sixty-eight and 26 phytochemicals were tentatively identified in L. glaucoides and L. glaucus, respectively, with phenolic compounds as the major class. Both plants showed significant inhibition of serum GPT and GOT levels, inhibition of tissue IL-1β and TNF-α levels and inhibition of tissue NF-κβ and caspase-3 gene expression proving hepatoprotective action. Liver treated with L. glaucoides showed lesion scoring range between negative to mild, whereas L. glaucus showed a range between mild to moderate.

The remarkable impact of RNA nanomedicine during the COVID-19 pandemic has demonstrated the expansive therapeutic potential of this field in diverse disease contexts. In recent years, RNA nanomedicine targeting the liver has been paradigm-shifting in the management of metabolic diseases such as hyperoxaluria and amyloidosis. RNA nanomedicine has significant potential in the management of liver diseases, where optimal management would benefit from targeted delivery, doses titrated to liver metabolism, and personalized therapy based on the specific site of interest. In this review, we discuss in-depth the different types of RNA and nanocarriers used for liver targeting along with their specific applications in metabolic dysfunction-associated steatotic liver disease, liver fibrosis, and liver cancers. We further highlight the strategies for cell-specific delivery and future perspectives in this field of research with the emergence of small activating RNA, circular RNA, and RNA base editing approaches.

Spontaneous clearance of hepatitis B virus (HBV) is frequent in adults (95%) but rare in infants (5%), emphasizing the critical role of age-related hepatic immunocompetence. However, the underlying mechanisms of hepatocyte-specific immunosurveillance and age-dependent HBV clearance remain unclear. Here, we identified PGLYRP2 as a hepatocyte-specific pattern recognition receptor with age-dependent expression, and demonstrated that phase separation of PGLYRP2 was a critical driver of spontaneous HBV clearance in hepatocytes. Mechanistically, PGLYRP2 recognized and potentially eliminated covalently closed circular DNA via phase separation, coordinated by its intrinsically disordered region and HBV DNA-binding domain (PGLYRP2IDR/209-377) in the nucleus. Additionally, PGLYRP2 suppressed HBV capsid assembly by directly interacting with the viral capsid, mediated by its PGRP domain. This interaction promoted the nucleocytoplasmic translocation of PGLYRP2 and subsequent secretion of the PGLYRP2/HBV capsid complex, thereby bolstering the hepatic antiviral response. Pathogenic variants or deletions in PGLYRP2 impaired its ability to inhibit HBV replication, highlighting its essential role in hepatocyte-intrinsic immunity. These findings suggest that targeting the PGLYRP2-mediated host-virus interaction may offer a potential therapeutic strategy for the development of anti-HBV treatments, representing a promising avenue for achieving a functional cure for HBV infection.

Gut-liver crosstalk plays an important role in alcohol-associated liver disease (ALD) pathogenesis; but underlying mechanisms remain obscure.

We examined the regulation of intestinal and intrahepatic CD8+ T lymphocytes and their contribution to ALD.

ALD patients were recruited for evaluation of intestinal and liver T cells. Single-cell RNA sequencing (scRNA seq) was performed to analyse intrahepatic and peripheral T cells in ALD. Wildtype, CD8-specific Bcl2 transgenic (Cd8 Bcl-2), and Cd8 -/- mice were subjected to chronic-plus-binge ethanol feeding.

In ALD patients, duodenal CD8+ T cells were selectively reduced and negatively correlated with liver injury and bacterial translocation markers, while intrahepatic CD8+ T cells were markedly increased. ScRNA seq analysis of ALD patient livers revealed several populations of CD8+ T cells expressing activation and survival genes (eg, Bcl2). Transcriptomics and functional studies revealed a key role of prosurvival BCL2 in this opposite regulation of CD8+ T cells. Mechanistically, chronic-plus-binge ethanol feeding reduced CD8+ T cells specifically in the duodenum where ethanol levels are high. Inducing BCL2 in CD8+ T cells reversed ethanol-induced loss of duodenal CD8+ T cells, improved gut barrier function and ameliorated ALD, while CD8 deficiency was linked to enhanced neutrophil and macrophage infiltration in the liver, exacerbating ALD in mice.

ALD is associated with loss of duodenal CD8+ T cells but elevation of intrahepatic CD8+ T cells, which aggravates and ameliorates ALD, respectively. Restoration of survival and functions of intestinal and intrahepatic CD8+ T cells may represent a novel therapeutic strategy for ALD patients.

The purpose of this review is to describe the immune function of the liver, guiding the reader from the homeostatic tolerogenic status to the aberrant activation demonstrated in chronic liver disease. An extensive description of the pathways behind the inflammatory modulation of the healthy liver will be provided focusing on the complex immune cell network residing within the liver. The limit of tolerance will be presented in the context of organ transplantation, seizing the limits of homeostatic mechanisms that fail in accepting the graft, progressing eventually toward rejection. The triggers and mechanisms behind chronic activation in metabolic liver conditions and viral hepatitis will be discussed. The last part of the review will be dedicated to one of the greatest paradoxes for a tolerogenic organ, developing autoimmunity. Through the description of the three most common autoimmune liver diseases, the autoimmune reaction against hepatocytes and biliary epithelial cells will be dissected.

Portal hypertension (PH) resulting from static and dynamic intrahepatic changes drives liver-related complications even after removing the underlying aetiological factor.

We investigated the impact of inflammation on the dynamic component of PH during disease regression in animal models of toxin-induced cirrhosis and patients with alcohol-related cirrhosis.

In mice, cirrhosis was induced via toxin application for 12 weeks followed by toxin-withdrawal allowing for one or 2 weeks of regression. Furthermore, 128 patients with alcohol-related cirrhosis and alcohol abstinence undergoing same-day hepatic venous pressure gradient (HVPG) and liver stiffness measurement (LSM) were included. The influence of inflammation on the dynamic PH component was assessed using linear models. Specifically, we explored proinflammatory changes in mice/patients in whom the measured portal pressure (PP)/HVPG was significantly higher than the PP/HVPG expected from the static PH component (histological collagen proportionate area [CPA; %] in mice, LSM in patients).

In mice, toxin discontinuation induced a significant decrease in PP, CPA, histological hepatic inflammation and hepatic expression of proinflammatory genes (Tnfa, Il6, Cxcl1, Mcp1; all p < 0.05 for one/2 week regression vs. peak disease). Similarly, prolonged abstinence in alcohol-related cirrhosis was linked to lower HVPG/LSM and longer abstinence was correlated to lower C-reactive protein (CRP), IL-6, immunoglobulin A (IgA) and IgG levels (all p < 0.05). Nevertheless, the persistence of a low-grade proinflammatory state during regression was linked to a higher PP/HVPG than expected from static PH components. In regressive mice, higher hepatic proinflammatory gene expression (Tnfa, Il6, Il1b; all p < 0.05) was linked to higher-than-expected PP. Similarly, higher CRP, IL-6, IgA and IgG and lower complement factor C3c (all p < 0.05) were associated with higher-than-expected HVPG in abstinent patients with alcohol-related cirrhosis.

Although removing the underlying aetiological factor resulted in significant improvements, a persistent hepatic proinflammatory environment remained a key driver of the dynamic PH component in regressive liver disease.

NCT03267615.

Populations of Black African (BA) ancestry are disproportionately affected by cardiometabolic diseases, possibly due to dysregulation of the complement system. This study aimed to determine relationships between fasting complement markers and cardiometabolic risk in BA and White European (WE) men, and whether postprandial complement response differs by ethnicity. Eighty-eight BA and 97 WE men [age = 44.4 (42.0-47.6) yr, body mass index (BMI) = 29.2 ± 4.5 kg·m-2] were assessed for fasting plasma complement markers and cardiometabolic risk factors. A second cohort (n = 20 men, 10 BA) [age = 31.0 ± 1.1 yr, BMI = 27.1 (26.0-28.6) kg·m-2] men underwent a moderate-to-high-fat feeding protocol to measure postprandial plasma complement, serum insulin, plasma glucose, triacylglycerol (TAG), and nonesterified fatty acids. C4 and Factor D were lower, and iC3b was higher in BA compared with WE men. C3 and C4 were strongly associated with all adiposity markers in both ethnicities, but the WE cohort showed stronger associations between C3 and subcutaneous adipose tissue, C5 and WC, and iC3b and visceral adipose tissue compared with BA. C3 was associated with all cardiometabolic risk factors in both ethnicities. Associations between C5 and cholesterol, C4 and TAG, and terminal complement complex and (both total and LDL)-cholesterol were only observed in the WE cohort. There was a trend toward ethnic differences in postprandial Factor D (P = 0.097) and iC3b (P = 0.085). The weaker associations between the complement system markers with adiposity and lipid profiles in BA compared with WE men suggest ethnic differences in the determinants of complement production and activation, whereby adipose tissue may play a less important role in BA men.NEW & NOTEWORTHY The present study found that markers of the complement system were less strongly associated with adiposity and lipid profiles in Black African men compared with White European men, suggesting ethnic differences in the determinants of complement production and activation. In Black African men, adipose tissue may play a less important role in complement production and activation and also in the link with traditional cardiometabolic risk factors.

Metastases arise from disseminated cancer cells (DCCs) that detach from the primary tumor and seed distant organs. There, quiescent DCCs can survive for an extended time, a state referred to as metastatic dormancy. The mechanisms governing the induction, maintenance, and awakening from metastatic dormancy are unclear. We show that the differentiation of dormancy-inducing CD8+ T cells requires CD4+ T cell help and that interferon (IFN)γ directly induces dormancy in DCCs. The maintenance of metastatic dormancy, however, is independent of T cells. Instead, awakening from dormancy requires an inflammatory signal, and we identified CD4+ T cell-derived interleukin (IL)-17A as an essential wake-up signal for dormant DCCs in the lungs. Thus, the induction of and awakening from metastatic dormancy require an external stimulus, while the maintenance of dormancy does not rely on continuous surveillance by lymphocytes.

Metabolic dysfunction-associated steatohepatitis (MASH) has become a serious public health problem, posing an increasingly dangerous threat to human health owing to its increasing prevalence and accompanying intra- and extrahepatic adverse outcomes. Rifaximin is considered to have therapeutic potential for MASH; however, its efficacy remains controversial. Our study aimed to observe the ameliorative effects of rifaximin and explore its possible mechanisms at the cellular level. 1. 42 male C57BL/6J mice were divided into 3 groups, the CON group and MCD group were fed with normal feed and MCD feed for 12 weeks respectively, and the MCD + RFX group was treated with rifaximin by gavage for 4 weeks on the basis of MCD feed. Hematoxylin-eosin staining, Sirius red staining and immunohistochemical staining were used to observe the histopathological changes of liver and intestine. Differences in liver transaminases, inflammatory factors, fibrosis indexes and intestinal tight junction proteins were compared among the 3 groups of mice. 2. A MASH cell model was constructed by inducing HepG2 cells with free fatty acids to observe the effects of rifaximin on MASH in vitro. In addition, the effects of rifaximin on TLR4/NF-κB signaling pathway were explored by applying TLR4 agonist LPS and TLR4 inhibitor TAK-242. Hepatic histopathology was significantly improved in MASH mice after rifaximin treatment, and their serum alanine aminotransferase and aspartate aminotransferase levels were (72.72 ± 5.68) U/L and (222.8 ± 11.22) U/L, respectively, which were significantly lower than those in the MCD group [(293.3 ± 10.69) U/L and (414.1 ± 36.29) U/L, P < 0.05], and the levels of inflammatory factors and fibrosis indicators were reduced. Rifaximin ameliorated intestinal barrier injury with increased expression of intestinal tight junction protein ZO-1 in the MCD + RFX group of mice, and the concentration of LPS-binding proteins (4.92 ± 0.55 vs. 15.82 ± 1.71, P < 0.05) was lower than that in the MCD group. In the NASH cell model, rifaximin similarly exerted inhibitory effects on its inflammatory factors and TLR4/NF-κB signaling pathway. Application of TLR4 inhibitors weakened the inhibitory effect of rifaximin on MASH. Our study supports rifaximin as a potential treatment for MASH, with potential mechanisms related to improving intestinal barrier integrity and downregulating the TLR4/NF-κB signaling pathway.

γδT cells, a distinct group of T lymphocytes, serve as a link between innate and adaptive immune responses. They are pivotal in the pathogenesis of various liver disorders, such as viral hepatitis, nonalcoholic fatty liver disease (NAFLD), alcoholic liver disease (ALD), liver fibrosis, autoimmune liver diseases, and hepatocellular carcinoma (HCC). Despite their importance, the functional diversity and regulatory mechanisms of γδT cells remain incompletely understood. Recent advances in high-throughput single-cell sequencing and spatial transcriptomics have revealed significant heterogeneity among γδT cell subsets, particularly Vδ1+ and Vδ2+, which exhibit distinct immunological roles. Vδ1+ T cells are mainly tissue-resident and contribute to tumor immunity and chronic inflammation, while Vδ2+ T cells, predominantly found in peripheral blood, play roles in systemic immune surveillance but may undergo dysfunction in chronic liver diseases. Additionally, γδT17 cells exacerbate inflammation in NAFLD and ALD, whereas IFN-γ-secreting γδT cells contribute to antiviral and antifibrotic responses. These discoveries have laid the foundation for the creation of innovative solutions. γδT cell-based immunotherapeutic approaches, such as adoptive cell transfer, immune checkpoint inhibition, and strategies targeting metabolic pathways. Future research should focus on harnessing γδT cells' therapeutic potential through targeted interventions, offering promising prospects for precision immunotherapy in liver diseases.

Drug-induced liver injury (DILI) presents a major challenge not only in new drug development but also in post-marketing withdrawals and the safety of food, cosmetics, and chemicals. Experimental model organisms such as the rodents have been widely used for preclinical toxicological testing. However, the tension exists associated with the ethical and sustainable use of animals in part because animals do not necessarily inform the human-specific ADME (adsorption, dynamics, metabolism and elimination) profiling. To establish alternative models in humans, in vitro hepatic tissue models have been proposed, ranging from primary hepatocytes, immortal hepatocytes, to the development of new cell resources such as stem cell-derived hepatocytes. Given the evolving number of novel alternative methods, understanding possible combinations of cell sources and culture methods will be crucial to develop the context-of-use assays. This review primarily focuses on 3D liver organoid models for conducting. We will review the relevant cell sources, bioengineering methods, selection of training compounds, and biomarkers towards the rationale design of in vitro toxicology testing.

To explore the causal relationship between serum albumin and venous thromboembolism (VTE) comprises deep vein thrombosis (DVT) and its consequential condition, pulmonary embolism (PE), through Mendelian randomization (MR) design, seeking to clarify the protective roles of albumin in the development of venous thrombosis.

We performed a bidirectional two-sample Mendelian randomization analysis utilizing albumin genome-wide association study (GWAS) data alongside VTE datasets from various sources. Additionally, to minimize heterogeneity across different datasets, a meta-analysis of the Mendelian randomization results was conducted. Furthermore, genes associated with such exposures were identified to unravel how exposure impacts outcomes. This was followed by applying bioinformatics techniques for gene enrichment analysis and employing the Cytoscape software to pinpoint the hub genes.

The findings from the meta-analysis of the Mendelian randomization indicate that reduced levels of albumin are associated with an elevated risk of VTE (OR = 0.739, 95% CI: 0.695 to 0.787, P = 1.82e-9), DVT (OR = 0.700, 95% CI: 0.646 to 0.772, P = 2.96e-15), and PE (OR = 0.717, 95% CI: 0.647 to 0.793, P = 1.74e-10). Bioinformatics analysis revealed that serum albumin primarily protects against VTE by influencing inflammation and cytokines.

Our bidirectional MR analysis confirmed a substantial causal association linking serum albumin to VTE. Bioinformatics analysis revealed that this causal link is mediated by the immune response through inflammation and cytokines.

Hepatic organoids (HOs), primarily composed of hepatobiliary cells, do not represent the pathogenesis of liver diseases due to the lack of non-parenchymal cells. Multi-lineage liver organoids (mLOs) containing various cell types found in the liver offer a promising in vitro disease model. However, their structural complexity remains challenging to achieve due to the difficulty in optimizing culture conditions that meet the growth need of all component cell types. Here, we demonstrate that cystic HOs generated from hPSCs can be expanded long-term and serve as a continuous source for generating complex mLOs. Assembling cystic HOs with hPSC-derived endothelial and hepatic stellate cell-like cells under conventional HO culture conditions failed to support the development of multiple cell types within mLOs, resulting in biased differentiation towards specific cell types. In contrast, modulating the cAMP/Wnt/Hippo signaling pathways with small molecules during assembly and differentiation phases efficiently generate mLOs containing both hepatic parenchymal and non-parenchymal cells. These mLOs exhibited structural complexity and functional maturity, including vascular network formation between parenchymal lobular structures, cell polarity for bile secretion, and the capacity to respond to fibrotic stimuli. Our study underscores the importance of modulating signaling pathways to enhance mLO structural complexity for applications in modeling liver pathologies.

This study aimed to evaluate the effects of dietary geniposide supplementation on growth performance, lipid metabolism, health status, and ammonia stress resistance in turbot (Scophthalmus maximus). Four hundred fifty fish were randomly allocated into 5 treatments with triplicate tanks (30 fish per tank). They were hand-fed to apparent satiety for 56 d with a basal diet (GP0) or diets containing 100, 200, 400, and 800 mg/kg geniposide (termed as GP100, GP200, GP400, GP800, respectively). After the conclusion of the feeding trial, the fish were exposed to ammonia stress for 96 h. The results showed that the growth performance were not affected by geniposide (P > 0.05). Dietary supplementation with geniposide decreased crude lipid in viscera without liver, subcutaneous adipose tissue (SAT), and the liver, as well as triglyceride concentrations in plasma, the liver and SAT (P < 0.05). Dietary supplementation with 400 and 800 mg/kg geniposide significantly down-regulated lipogenesis-related gene expression, as well as fatty acid uptake-related gene expression, while significantly up-regulated triglyceride secretion-related gene expression in the liver compared with the control group (P < 0.05). The GP800 group exhibited a significant reduction in plasma malondialdehyde contents compared with the control group, while both the GP200 and GP800 groups showed a significant increase in plasma complement C3 activities (P < 0.05). Furthermore, there was a notable enhancement in plasma lysozyme and total superoxide dismutase levels in the geniposide supplemented groups compared to the control group (P < 0.05). Additionally, a significant decrease in the mRNA level of pro-inflammatory cytokine and a remarkable increase in the mRNA expression of anti-inflammatory cytokines were discovered in geniposide supplemented groups relative to the control group (P < 0.05). Cumulative survival rates after ammonia stress in the GP400 and GP800 groups were statistically higher than that in the control group (P < 0.05). In conclusion, dietary geniposide supplementation could reduce lipid deposition in turbot by regulating lipid metabolism and transportation, and remarkably enhance immunity, antioxidant ability, and resistance to ammonia stress in turbot. Based on the quadratic regression analyses, the optimal concentrations of geniposide were estimated to be 545.21 to 668.41 mg/kg feed.

Over the past several years, the therapeutic landscape for patients with advanced, unresectable, or metastatic hepatocellular carcinoma has been transformed by the incorporation of checkpoint inhibitor immunotherapy into the treatment paradigm. Frontline systemic treatment options have expanded beyond anti-angiogenic tyrosine kinase inhibitors, such as sorafenib, to a combination of immunotherapy approaches, including atezolizumab plus bevacizumab and durvalumab plus tremelimumab, both of which have demonstrated superior response and survival to sorafenib. Additionally, combination treatments with checkpoint inhibitors and tyrosine kinase inhibitors have been investigated with variable success. In this review, we discuss these advances in systemic treatment with immunotherapy, with a focus on understanding both the underlying biology and mechanism of these strategies and their efficacy outcomes in clinical trials. We also review challenges in identifying predictive biomarkers of treatments and discuss future directions with novel immunotherapy targets.

Cirrhosis is associated with a proinflammatory environment.

To analyse aetiology-specific inflammation patterns in compensated cirrhosis in animal models and patients.

Portal pressure (PP), fibrosis (collagen proportionate area [CPA]) and hepatic inflammation were measured in cirrhotic rat models (thioacetamide [TAA;n = 12]; choline-deficient high-fat diet [CDHFD;n = 12]; bile duct ligation [BDL;n = 16]). Compensated cirrhotic patients (alcohol-related liver disease [ALD;n = 67]; metabolic dysfunction-associated steatohepatitis [MASH;n = 50]; cholestatic liver disease [primary biliary cholangitis [PBC]/primary sclerosing cholangitis [PSC];n = 22]) undergoing hepatic venous pressure gradient (HVPG) measurement were included.

In rats, hepatic proinflammatory gene expression was highest in CDHFD and lowest in TAA, despite comparable PP levels. Across all animal models, Tnfa/Il6 correlated positively with CPA, and Mcp1 with elevated PP. Mcp1 was also associated with increased CPA in TAA/CDHFD. Mcp1/Cxcl1 showed a model-independent positive correlation to transaminases. Il1b correlated positively with CPA/PP in BDL and with transaminases in CDHFD. In patients, CRP/IL-6 were lower in MASH compared to ALD or PBC/PSC, regardless of hepatic function. IgA/IgG were highest and complement factors lowest in ALD. More pronounced systemic inflammation was linked to higher HVPG primarily in ALD/MASH.

Proinflammatory pathways are upregulated across all liver disease aetiologies, yet their association with fibrosis and portal hypertension can vary.

Clarias dussumieri, an air breathing catfish endemic to the Western Ghats in India, is categorized as 'Near Threatened' by the IUCN. This species is of high regional consumer demand and is one of the prioritized candidate species for aquaculture diversification and conservation. Despite its ecological and commercial significance, comprehensive studies on its immune system are lacking. This study elucidates the ontogenetic development and tissue-specific (brain, anterior kidney, gill, spleen, muscle, liver, hindgut and skin) expression profiles of key immune-related genes in C. dussumieri. Larvae were sampled at various developmental stages post-fertilization, and tissues from adult fish were analyzed for expression patterns of genes associated with inflammation (IL-1β, TNF-α, iNOS), antimicrobial defense (LYS, HAMP), stress response (HSP70), complement system (C3), cell-mediated immunity (MHC-IIβ, CD4-1), and adaptive immunity (IgM). The expression of IL-1β was highest at 60 days post-fertilization (60D), while TNF-α expression peaked at 25D before dropping notably by 60D. iNOS showed a peak at 7D, underscoring its importance in early immune defence. LYS exhibited a high expression at 10D, while HAMP peaked at 60D, highlighting their roles in antimicrobial defence. Stress marker HSP70 increased from 15D onwards and complement component C3 was consistently expressed at low levels throughout development. MHC-IIβ and CD4-1 showed significant increase since 10D and 7D respectively, suggesting the establishment of cell-mediated immunity. IgM expression increased notably from 15 days, indicating the development of adaptive immunity. In adult fish tissues, IL-1β, TNF-α, LYS and HSP70 showed highest expression in the hindgut, while C3 was predominantly expressed in the liver. MHC-IIβ and CD4-1 were highly expressed in the spleen and anterior kidney respectively. IgM was abundant in the anterior kidney and spleen. This study provides crucial baseline data on the immune competence of different developmental stages of C. dussumieri, informing strategies for effective vaccination and disease management in aquaculture, and enhancing our understanding of fish immunology for conservation efforts.

Kupffer cells are pivotal in initiating hepatocyte proliferation and establishing connections between different cell types during liver regeneration following partial hepatectomy. As resident macrophages within the liver, Kupffer cells collaborate with hepatocytes and non-parenchymal cells to release various inflammatory mediators that promote hepatocyte proliferation through induction signals like STAT3 phosphorylation. Additionally, the regeneration and replenishment of Kupffer cells themselves are integral components of liver regeneration. The supplementation of the Kupffer cell pool primarily occurs through two pathways: one involves local proliferation of Kupffer cells in their original location, while the other entails infiltration of circulating monocytes into the liver, followed by acquiring Kupffer cell phenotypes under the combined influence of multiple inducing factors. Extensive research has focused on intercellular crosstalk among various types of liver cells during liver regeneration, highlighting the crucial role played by Kupffer cells. This article aims to introduce Kupffer cells and their involvement in liver regeneration, as well as discuss the steady-state balance of Kupffer cell pools during this process.

Sulfatides or 3-O-sulfogalactosylceramide are negatively charged sulfated glycosphingolipids abundant in the brain and kidneys and play crucial roles in nerve impulse conduction and urinary pH regulation. Sulfatides are present in the liver, specifically in the biliary tract. Sulfatides are self-lipid antigens presented by cholangiocytes to activate cluster of differentiation 1d (CD1d)-restricted type II natural killer T (NKT) cells. These cells are involved in alcohol-related liver disease (ArLD) and ischemic liver injury and exert anti-inflammatory effects by regulating the activity of pro-inflammatory type I NKT cells. Loss of sulfatides has been implicated in the chronic inflammatory disorder of the liver known as primary sclerosing cholangitis (PSC); bile ducts deficient in sulfatides increase their permeability, resulting in the spread of bile into the liver parenchyma. Previous studies have shown elevated levels of sulfatides in hepatocellular carcinoma (HCC), where sulfatides could act as adhesive molecules that contribute to cancer metastasis. We have recently demonstrated how loss of function of GAL3ST1, a limiting enzyme involved in sulfatide synthesis, reduces tumorigenic capacity in cholangiocarcinoma (CCA) cells. The biological function of sulfatides in the liver is still unclear; however, this review aims to summarize the existing findings on the topic.

Interleukin-6 (IL-6) plays a central role in sepsis-induced cytokine storm involving immune hyperactivation and early neutrophil activation. Programmed death protein-1 (PD-1) is associated with sepsis-induced immunosuppression and lymphocyte apoptosis. However, the effects of simultaneous blockade of IL-6 and PD-1 in a murine sepsis model are not well understood.

In this study, sepsis was induced in male C57BL/6 mice through cecal ligation and puncture (CLP). IL-6 blockade, PD-1 blockade, or combination of both was administered 24 h after CLP. Peripheral blood count, cytokine level, lymphocyte apoptosis in the spleen, neutrophil infiltration in the lungs and liver, and survival rate were measured. The mortality rate of the IL-6/PD-1 group was lower, though not statistically significant (p = 0.164), than that of CLP mice (75.0% vs. 91.7%). The IL-6/PD-1 group had lower neutrophil percentage and platelet count compared with the CLP group; no significant difference was observed in other cytokine levels. The IL-6/PD-1 group also showed reduced T lymphocyte apoptosis in the spleen and decreased neutrophil infiltration in the liver and lungs.

IL-6/PD-1 dual blockade reduces neutrophil infiltration, lymphocyte apoptosis, and bacterial burden while preserving tissue integrity in sepsis. Although the improvement in survival was not statistically significant, these findings highlight its potential as a therapeutic approach in sepsis.

Healthy livers contain a large number of resident macrophages named Kupffer cells (KCs), which are partially replaced by infiltrating monocyte-derived macrophages (MoMFs) during acute or chronic liver injury. Despite extensive research, understanding macrophage heterogeneity, spatial distribution and interactions with other cells within the liver remains challenging.

This study employs sequential multiplex immunofluorescence staining, advanced image analysis and single-cell RNA sequencing (scRNA-seq) analysis to characterise macrophages in both healthy and diseased livers in mice.

Our data revealed that liver KCs made up more than 80% of total immune cells in healthy mouse livers, while massive amounts of MoMFs infiltrated into the livers after acute and chronic liver injury. KCs were more abundant and larger in Zones 1 and 2 compared with Zone 3 in healthy livers. Zone 1 KCs exhibited higher phagocytic activity than Zone 2/3 KCs and MoMFs. We simultaneously evaluated cell proliferation and apoptosis on one slide and found that proliferation and apoptosis of KCs and MoMFs significantly increased in acutely injured livers. We also performed scRNA-seq to investigate liver macrophage gene expression in naïve and concanavalin A (ConA)-treated mice. MoMF clusters expanded following ConA treatment, while KCs remained stable. Macrophages were divided into distinct subtypes, including C1q+ MoMFs, with differential expression of genes like Trem2, Spp1, Fabp5 and Gpnmb. Newly recruited C1q- MoMFs expressed high levels of Lyz and Ccr2, while Itgax (Cd11c)+ MoMFs expressed endothelin converting enzyme 1 (Ece1), a gene encoding ECE1 enzyme that activates endothelin to promote hepatic stellate cell contraction and necrotic lesion resolution. By immunostaining analysis of the proteins encoded by these signature genes, we identified several populations of MoMFs that were mainly located surrounding the necrotic lesion area and expressed various proteins that are involved in dead cell debris clearance.

We developed a robust framework for studying liver macrophages in vivo, offering insights into their roles in host defence and liver injury/repair. We identified several populations of MoMFs that surround necrotic lesion areas and express proteins that promote dead cell debris clearance. These necrotic lesion-associated macrophages likely play key roles in promoting necrotic lesion resolution.

Aeromonas hydrophila causes motile Aeromonas septicemia (MAS) in freshwater fish. In recent years, MAS outbreaks due to virulent Aeromonas hydrophila (vAh) have been responsible for large-scale losses within commercial catfish farms in Mississippi and Alabama. The aim of this study was to evaluate immune gene expression in catfish immune-competent tissues during infection with vAh strain ML09-119. Specific pathogen-free catfish fingerlings were intraperitoneally infected with vAh strain ML09-119, and relative expression of thirteen immune-related genes was evaluated from head kidney, spleen, and liver. Our results revealed that vAh was detected 2 h post-infection (hpi) in the head kidney, liver, and spleen. The highest concentration of vAh was detected at 12 hpi, from which point concentrations decreased until clearance at 5 days post-infection (dpi). Gene expression analysis revealed upregulation of pro-inflammatory cytokines and innate immune response (TLR 4 and 5) in the first 24 hpi. Adaptive immune-related genes were upregulated at 7 dpi in the spleen and 14 dpi in the head kidney. Furthermore, immunoglobulin M showed significant upregulation at 14 dpi in the head kidney and 21 dpi in the spleen. In summary, vAh ML09-119 infection induced a strong inflammatory response involving multiple innate immunity genes, proinflammatory cytokines, and chemokines. Surviving catfish were able to clear the infection and produce antibodies and memory cells. Assessment of the immunological response to vAh infection is critical for understanding the pathogen's mechanisms of pathogenesis and developing means for MAS control, including vaccine development and improved treatments.

Prolonged immunosuppressive therapy in liver transplantation (LT) is associated with significant adverse effects, such as nephrotoxicity, metabolic complications, and heightened risk of infection or malignancy. Regulatory T cells (Tregs) represent a promising target for inducing immune tolerance in LT, with the potential to reduce or eliminate the need for life-long immunosuppression. This review summarizes current knowledge on the roles of Tregs in LT, highlighting their mechanisms and the impact of various immunosuppressive agents on Treg stability and function. The liver's distinct immunological microenvironment, characterized by tolerogenic antigen-presenting cells and high levels of interleukin (IL)-10 and transforming growth factor-β, positions this organ as an ideal setting for Treg-mediated tolerance. We discuss Treg dynamics in LT, their association with rejection risk, and their utility as biomarkers of transplant outcomes. Emerging strategies, including the use of low-dose calcineurin inhibitors with mammalian target of rapamycin inhibitors, adoptive Treg therapy, and low-dose IL-2, aim to enhance Treg function while providing sufficient immunosuppression. Thus, the future of LT involves precision medicine approaches that integrate Treg monitoring with tailored immunosuppressive protocols to optimize long-term outcomes for LT recipients.

Non-alcoholic fatty liver disease (NAFLD), which is a significant liver condition associated with metabolic syndrome, is the leading cause of liver diseases globally and its prevalence is on the rise in most nations. The protective impact of vitamin D on NAFLD and its specific mechanism remains unclear.

To examine the role of vitamin D in NAFLD and how vitamin D affects the polarization of hepatic macrophages in NAFLD through the vitamin D receptor (VDR)-peroxisome proliferator activated receptor (PPAR)γ pathway.

Wild-type C57BL/6 mice were provided with a high-fat diet to trigger NAFLD model and administered 1,25-dihydroxy-vitamin D [1,25(OH)2D3] supplementation. 1,25(OH)2D3 was given to RAW264.7 macrophages that had been treated with lipid, and a co-culture with AML12 hepatocytes was set up. Lipid accumulation, lipid metabolism enzymes, M1/M2 phenotype markers, proinflammatory cytokines and VDR-PPARγ pathway were determined.

Supplementation with 1,25(OH)2D3 relieved hepatic steatosis and decreased the proinflammatory M1 polarization of hepatic macrophages in NAFLD. Administration of 1,25(OH)2D3 suppressed the proinflammatory M1 polarization of macrophages induced by fatty acids, thereby directly relieving lipid accumulation and metabolism in hepatocytes. The VDR-PPARγ pathway had a notable impact on reversing lipid-induced proinflammatory M1 polarization of macrophages regulated by the administration of 1,25(OH)2D3.

Supplementation with 1,25(OH)2D3 improved hepatic steatosis and lipid metabolism in NAFLD, linked to its capacity to reverse the proinflammatory M1 polarization of hepatic macrophages, partially by regulating the VDR-PPARγ pathway. The involvement of 1,25(OH)2D3 in inhibiting fatty-acid-induced proinflammatory M1 polarization of macrophages played a direct role in relieving lipid accumulation and metabolism in hepatocytes.

Hepatocellular carcinoma (HCC), a major subtype of liver cancer, poses significant therapeutic challenges due to its late diagnosis and rapid progression. The evolving landscape of immunotherapy offers a beacon of hope, with natural killer (NK) cells emerging as pivotal players in combating HCC. NK cells are unique cytotoxic lymphocytes that are essential in the fight against infections and malignancies. Phenotypic and functional NK cell abnormalities have been shown in HCC patients, indicating their significance as a component of the innate immune system against cancer. This review elucidates the critical role of NK cells in combating HCC, focusing on their interaction with the tumor microenvironment, the development of NK cell-based therapies, and the innovative strategies to enhance their efficacy in the immunosuppressive milieu of HCC. The review delves into the various therapeutic strategies, including autologous and allogeneic NK cell therapies, genetic engineering to improve NK cell resilience and targeting, and the integration of NK cells with other immunotherapeutic approaches like checkpoint inhibitors and oncolytic virotherapy. By highlighting recent advancements and the ongoing challenges in the field, this review sets the stage for future research directions that could unlock the full potential of NK cell-based immunotherapy for HCC, offering a beacon of hope for patients battling this formidable cancer.

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.

Liver disease has emerged as a significant health concern, characterized by high rates of morbidity and mortality. Circulating exosomes have garnered attention as important mediators of intercellular communication, harboring protein and stable mRNAs, microRNAs, and long non-coding RNAs (lncRNA). This review highlights the involvement of exosomal lncRNA in the pathogenesis and diagnosis of various liver diseases. Notably, exosomal lncRNAs exhibit therapeutic potential as targets for conditions including hepatic carcinoma, hepatic fibrosis, and hepatic viral infections.

An online screening process was employed to identify studies investigating the association between exosomal lncRNA and various liver diseases.

Our study revealed a diverse array of lncRNAs carried by exosomes, including H19, Linc-ROR, VLDLR, MALAT1, DANCR, HEIH, ENSG00000248932.1, ENST00000457302.2, ZSCAN16-AS1, and others, exhibiting varied levels across different liver diseases compared to normal liver tissue. These exosomal-derived lncRNAs are increasingly recognized as pivotal biomarkers for diagnosing and prognosticating liver diseases, supported by emerging evidence. However, the precise mechanisms underlying the involvement of certain exosomal lncRNAs remain incompletely understood. Furthermore, the combined analysis of serum exosomes using ENSG00000258332.1, LINC00635, and serum AFP may serve as novel and valuable biomarker for HCC. Clinically, exosomal ATB expression is upregulated in HCC, while exosomal HEIH and RP11-513I15.6 have shown potential for distinguishing HCC related to HCV infection.

The lack of reliable biomarkers for liver diseases, coupled with the high specificity and sensitivity of exosomal lncRNA and its non-invasive detection, promotes exploring their role in pathogenesis and biomarker for diagnosis, prognosis, and response to treatment liver diseases.

Cancer cells evolve under unique functional adaptations that unlock transcriptional programs embedded in adult stem and progenitor-like cells for progression, metastasis, and therapeutic resistance. However, it remains challenging to quantify the stemness-aware cell state of a tumor based on its gene expression profile.

We develop a developmental-status-aware transcriptional decomposition strategy using single-cell RNA-sequencing-derived tissue-specific fetal and adult cell signatures as anchors. We apply our method to various biological contexts, including developing human organs, adult human tissues, experimentally induced differentiation cultures, and bulk human tumors, to benchmark its performance and to reveal novel biology of entangled developmental signaling in oncogenic processes.

Our strategy successfully captures complex dynamics in developmental tissue bulks, reveals remarkable cellular heterogeneity in adult tissues, and resolves the ambiguity of cell identities in in vitro transformations. Applying it to large patient cohorts of bulk RNA-seq, we identify clinically relevant cell-of-origin patterns and observe that decomposed fetal cell signals significantly increase in tumors versus normal tissues and metastases versus primary tumors. Across cancer types, the inferred fetal-state strength outperforms published stemness indices in predicting patient survival and confers substantially improved predictive power for therapeutic responses.

Our study not only provides a general approach to quantifying developmental-status-aware cell states of bulk samples but also constructs an information-rich, biologically interpretable, cell-state panorama of human cancers, enabling diverse translational applications.

Increasing attention is being paid to the toxic physiological effects of nanoplastics (NPs) on aquatic organisms. However, few studies have systematically evaluated the regulatory mechanisms of NPs on immune response in crustaceans. In this study, a 28-day chronic exposure experiment was conducted in which shrimps were exposed to various 80-nm polystyrene NPs concentrations (0, 0.1, 1, 5 and 10 mg/L). Transcriptomic analysis was used to investigate the regulatory mechanisms of NPs in immune response of Litopenaeus vannamei. With increasing NPs concentration, the total hemocyte count (THC) content decreased, while phagocytosis rate (PR) and respiratory burst (RB) showed trends of first rising and then falling. High concentration (10 mg/L) of NPs caused the destruction of hepatopancreas tissue structure, the shedding of microvilli, the increase number of hepatocyte apoptosis and autophagy structure. With increasing NPs concentration, the lysozyme (Lys), superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities first increased and then decrease, while contents of lipid peroxidation and malondialdehyde increased; the expression levels of Toll, MyD88, GPx, SOD, proPO, Lys, and ALF generally increased at first and then decreased. Transcriptional sequencing analysis showed that the pathway of differentially expressed genes in KEGG enrichment mainly included lysosome (ko04142), apoptosis (ko04210) pathways, indicating that the NPs mainly affected the immune regulatory mechanism. Further analysis by Gene Set Enrichment Analysis (GSEA) showed that the up-regulation pathways of NPs activation mainly included immune response-related pathways such as mitochondrial autophagy, DNA repair, autophagosomes signaling pathway. Our results indicated that NPs exposure induced oxidative stress, apoptosis and autophagy in shrimps. This study provides a basis for further understanding of the mechanisms of antioxidant immune regulation by NPs in shrimp and may serve as a reference for healthy ecological culture of shrimp.

Fasciola hepatica and Dicrocoelium dendriticum are parasitic trematodes residing in the bile ducts of mammalian hosts, causing, in some cases, impairment of liver function and hepatic fibrosis. Previous studies have shown that extracellular vesicles released by F. hepatica (FhEVs) and D. dendriticum (DdEVs) induce a distinct phenotype in human macrophages, but there is limited information on the effect of parasitic EVs on liver cells, which interact directly with the worms in natural infections. In this study, we isolated FhEVs and DdEVs by size exclusion chromatography and labeled them with a lipophilic fluorescent dye to analyze their uptake by human hepatic stellate cells (HSC) and hepatocytes, important cell types in liver pathology, using synthetic liposomes as internal labeling and uptake control. We analyzed EV uptake and the proteome profiles after the treatment with EVs for both cell types. Our results reveal that EVs establish unique and specific interactions with stellate cells and hepatocytes, suggesting a different role of EVs derived from each parasite, depending on the migration route to reach their final niche. FhEVs have a cytostatic effect on HSCs, but induce the extracellular matrix secretion and elicit anti-inflammatory responses in hepatocytes. DdEVs have a more potent anti-proliferative effect than FhEVs and trigger a global inflammatory response, increasing the levels of NF-κB and other inflammatory mediators in both cell types. These interactions may have a major influence on the progression of the disease, serving to generate conditions that may favor the establishment of the helminths in the host.

Systemic inflammation and immunodeficiency are important components of cirrhosis-associated immune dysfunction (CAID), the severity of which is dynamic, progressive, and associated with the greater deterioration of liver function. Two inflammation phenotypes have been described: low-grade and high-grade systemic inflammation. Both of these phenotypes are related to liver cirrhosis function; thus, high-grade inflammation is correlated with the severity of hepatic insufficiency, bacterial translocation, and organic insufficiency, with which the risk of infections increases and the prognosis worsens. Bacterial translocation (BT) plays a relevant role in persistent systemic inflammation in patients with cirrhosis, and the prophylactic employment of antibiotics is useful for reducing events of infection and mortality.

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.

Arginine (ARG)/Citrulline (CIT) deficiency is associated with increased sepsis severity after infection. Supplementation of CIT to susceptible patients with ARG/CIT deficiency such as preterm newborns with suspected infection might prevent sepsis, via maintaining immune and vascular function. Caesarean-delivered, parenterally nourished preterm pigs were treated with CIT (1g/kg bodyweight) via oral or continuous intravenous supplementation, then inoculated with live Staphylococcus epidermidis and clinically monitored for 14 h. Blood, liver, and spleen samples were collected for analysis. In vitro cord blood stimulation was performed to explore how CIT and ARG affect premature blood cell responses. After infection, oral CIT supplementation led to higher mortality, increased blood bacterial load, and systemic and hepatic inflammation. Intravenous CIT administration showed increased inflammation and bacterial burdens without significantly affecting mortality. Liver transcriptomics and data from in vitro blood stimulation indicated that CIT induces systemic immunosuppression in preterm newborns, which may impair resistance response to bacteria at the early stage of infection, subsequently causing later uncontrollable inflammation and tissue damage. The early stage of CIT supplementation exacerbates sepsis severity in infected preterm pigs, likely via inducing systemic immunosuppression.

Differentiation of multipotential progenitor cells is a key process in the development of any multi-cellular organism and often continues throughout its life. It is often assumed that a bi-potential progenitor develops along a (relatively) straight trajectory until it reaches a decision point where the trajectory bifurcates. At this point one of two directions is chosen, each direction representing the unfolding of a new transcriptional programme. However, we have lacked quantitative means for testing this model. Accordingly, we have developed the R package TrajectoryGeometry. Applying this to published data we find several examples where, rather than bifurcate, developmental pathways branch. That is, the bipotential progenitor develops along a relatively straight trajectory leading to one of its potential fates. A second relatively straight trajectory branches off from this towards the other potential fate. In this sense only cells that branch off to follow the second trajectory make a 'decision'. Our methods give precise descriptions of the genes and cellular pathways involved in these trajectories. We speculate that branching may be the more common behaviour and may have advantages from a control-theoretic viewpoint.

Hepatocytes synthesize a vast number of glycoproteins found in their membranes and secretions, many of which contain O-glycans linked to Ser/Thr residues. As the functions and distribution of O-glycans on hepatocyte-derived membrane glycoproteins and blood glycoproteins are not well understood, we generated mice with a targeted deletion of Cosmc (C1Galt1c1) in hepatocytes. Liver glycoproteins in WT mice express typical sialylated core 1 O-glycans (T antigen/CD176) (Galβ1-3GalNAcα1-O-Ser/Thr), whereas the Cosmc knockout hepatocytes (HEP-Cosmc-KO) lack extended O-glycans and express the Tn antigen (CD175) (GalNAcα1-O-Ser/Thr). Tn-containing glycoproteins occur in the sera of HEP-Cosmc-KO mice but not in WT mice. The LDL-receptor (LDLR), a well-studied O-glycosylated glycoprotein in hepatocytes, behaves as a ∼145kD glycoprotein in WT liver lysates, whereas it is reduced to ∼120 kDa in lysates from HEP-Cosmc-KO mice. Interestingly, the expression of the LDLR, as well as HMG-CoA reductase, which is typically altered in response to dysregulated cholesterol metabolism, are similar between WT and HEP-Cosmc-KO mice, indicating no significant effect by Cosmc deletion on either LDLR stability or cholesterol metabolism. Consistent with this, we observed no detectable phenotype in the HEP-Cosmc-KO mice regarding development, appearance or aging compared to WT. These results provide surprising, novel information about the pathway of O-glycosylation in the liver.