High levels of M2 macrophages often correlate with poor prognosis. Endoglin (ENG) is a potential target for anti-angiogenesis therapy in various cancers, but the link between M2 macrophages and metabolism-related genes (MRGs) in hepatocellular carcinoma (HCC) is unclear. We employed cibersort analysis to identify genes associated with M2 macrophages and metabolic reprogramming in HCC, utilizing data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. TCGA data were stratified basis on ENG expression levels, and the relationships between ENG and relevant genes were assessed alongside clinical features. Furthermore, we validated ENG expression in HCC tissues and its correlation with M2 macrophages via qRT-PCR, Western blotting (WB), and immunohistochemistry (IHC). Patients with high ENG expression presented superior overall survival (OS) and longer progression-free survival (PFS). Univariate and multivariate regression analyses identified ENG as an independent prognostic predictor. Moreover, GSEA, GO, and KEGG analyses suggested a correlation between ENG-related gene expression and immunity, particularly TAMs. Additionally, ENG was found to reshape the tumor microenvironment (TME) of HCC and influence the response to immunotherapy. Single-cell analysis revealed the differential expression and distribution of ENG in the TME. In vitro experiments demonstrated lower ENG expression in HCC tissues than in paracancerous tissues, with a concomitant correlation with M2 macrophages. ENG emerges as a novel predictive marker for HCC, could reshap the TME and impacts the response to immunotherapy and provides a fresh perspective for investigating combined immunotherapy targeting MRGs in HCC.

Liver disease that progresses to cirrhosis is an enormous health problem worldwide. The extracellular matrix protein Mindin is known to have immune functions, but its role in liver homeostasis remains largely unexplored. We aimed to characterize the role of Mindin in the regulation of liver fibrosis.

Mindin was upregulated in mice with carbon tetrachloride (CCl4) or thioacetamide (TAA)-induced liver fibrosis, and was primarily expressed in hepatocytes. Global Mindin knockout mice were generated, which were susceptible to liver fibrosis. Notably, Mindin failed to activate hepatic stellate cells directly; however, it played a role in promoting the recruitment and phagocytosis of macrophages, and caused a phenotypic switch toward restorative macrophages during liver fibrosis. Furthermore, Mindin was found to bind to the αM-I domain of CD11b/CD18 heterodimeric receptors. To further explore this mechanism, we created Mindin and CD11b double-knockout (DKO) mice. In DKO mice, phagocytosis was further reduced, and liver fibrosis was markedly exacerbated.

Mindin promotes the resolution of liver fibrosis and the Mindin/CD11b axis might represent a novel target for the macrophage-mediated regression of liver fibrosis.

Alcoholic liver disease (ALD) is a common liver condition caused by long-term alcohol consumption, and its specific molecular mechanism remains unclear. It may be influenced to some extent by ferroptosis and Porphyromonas gingivalis (P.g), which is an important pathogen of periodontitis.

C57BL/6 J mice and AML12 cells were selected as the study subjects. The periodontitis model was induced using P.g, and the alcoholic liver model was created. Pathological analysis was performed on the liver, intestine, and periodontal tissues. 16S rRNA sequencing was used to analyze changes in the intestinal flora and intestinal gap junction protein (zonula occludens-1 (ZO-1) and occludin) levels in each group. Ferroptosis indices were detected in the liver tissues and AML12 cells.

Oral exposure to P.g induced mice periodontitis and exacerbated alcohol-related liver injury. Both alcohol and P.g caused intestinal flora disturbance, damage to the intestinal epithelial barrier, increased permeability, and activation of mouse hepatocyte ferroptosis. Furthermore, P.g aggravated such alcohol-induced liver damage.

Both alcohol and P.g can lead to intestinal flora disturbance, damage to the intestinal epithelial barrier, increased permeability, and the activation of mouse hepatocyte ferroptosis, and P.g can aggravate such alcohol-induced liver damage. Acyl-CoA synthetase long-chain family member 4 (ACSL4) and heme oxygenase-1 (HO-1) play important roles in the exacerbation of alcoholic liver injury by P.g.

In murine models of visceral leishmaniasis (VL), the parasitization of resident Kupffer cells (resKCs) drives early Leishmania infantum growth in the liver, leading to granuloma formation and subsequent parasite control. Using the chronic VL model, we demonstrate that polyclonal resKCs redistributed to form granulomas outside the sinusoids, creating an open sinusoidal niche that was gradually repopulated by monocyte-derived KCs (moKCs) acquiring a tissue specific, homeostatic profile. Early-stage granulomas predominantly consisted of CLEC4F+KCs. In contrast, late-stage granulomas led to remodeling of the sinusoidal network and contained monocyte-derived macrophages (momacs) along with KCs that downregulated CLEC4F, with both populations expressing iNOS and pro-inflammatory chemokines. During late-stage infection, parasites were largely confined to CLEC4F-KCs. Reduced monocyte recruitment and increased resKCs proliferation in infected Ccr2-/- mice impaired parasite control. These findings show that the ontogenic heterogeneity of granuloma macrophages is closely linked to granuloma maturation and the development of hepatic immunity in VL.

The main challenge for cancer therapy lies in immuno-suppressive tumor micro-environment. Reprogramming tumor-associated macrophages (TAMs) into an anti-tumor phenotype is a promising strategy.

A comprehensive analysis by combing multi-regional single-cell, bulk and spatial transcriptome profiling with radiomics characterization was conducted to dissect the heterogeneity of TAMs and resolve the landscape of the CXCL9:SPP1 (CS) macrophage polarity in HCC.

TAMs were particularly increased in HCC. SPP1+ TAMs and CXCL9+ TAMs were identified as the dominant subtypes with different evolutionary trajectories. SPP1+ TAMs, located in the tumor core, co-localized with cancer-associated fibroblasts to promote tumor growth and further contributed to worse prognosis. In contrast, CXCL9+ TAMs, located in the peritumoral region, synergized with CD8+ T cells to create an immunostimulatory micro-environment. For the first time, we explored the applicability of CS polarity in HCC tumors and revealed several key transcription factors involved in shaping this polarity. Moreover, CS polarity could serve as a potential indicator of prognostic and micro-environmental status for HCC patients. Based on medical imaging data, we developed a radiomics tool, RCSP (Radiogenomics-based CXCL9/SPP1 Polarity), to assist in non-invasively predicting the CS polarity in HCC patients.

Our research sheds light on the regulatory roles of SPP1+ TAMs and CXCL9+ TAMs in the micro-environment and provides new therapeutic targets or insights for the reprogramming of targeted macrophages in HCC.

Macrophages play an important role in disease progression of pediatric cholestatic liver disease, particularly biliary atresia (BA); however, the restorative versus pathogenic role for precise macrophage subsets remains poorly defined. We aimed to distinguish the transcriptional profiles and roles of defined macrophage subset(s) in murine BA.

We used multiparameter flow cytometry and RNA-sequencing analysis to profile recruited CD11bhiCD64+ hepatic macrophages by cell surface expression of MHCII and Ly6c in the Rhesus rotavirus (RRV)-induced murine model of BA versus saline controls. Modulation of macrophage numbers via intra-peritoneal injections of clodronate-loaded liposomes was performed to determine the association between macrophage numbers and histologic injury (Ishak score).

Ly6c+ macrophages demonstrated the greatest increase in numbers and percent of total macrophages in murine BA versus saline controls whereas MHCII+ macrophages decreased. Transcriptional changes in murine BA MHCII+ macrophages included reduced expression of the Kupffer cell gene signature, lower expression of genes involved in homeostatic processes, and increased expression of genes involved in inflammatory processes. Ly6c+ macrophages in murine BA showed increased expression for Hif1a and other genes involved in the cellular response to hypoxia. Among all subsets, the number of Ly6c+ macrophages exhibited the strongest correlation with severity of histologic liver injury by Ishak score.

Our data identify specific pathways upregulated in Ly6c vs MHCII+ macrophage subsets in murine BA. Transcriptional similarities between murine BA and human cholestatic macrophages may enable translation of future mechanistic studies to new macrophage subset-specific therapies.

Chronic liver diseases are highly linked with mitochondrial dysfunction and macrophage infiltration. Mallory-Denk bodies (MDBs) are protein aggregates associated with hepatic inflammation, and MDBs pathogenesis could be induced in mice by feeding 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC). Here, we investigate the macrophage heterogeneity and the role of macrophage during MDBs pathogenesis on DDC-induced MDBs mouse model by single-nucleus RNA sequencing (snRNA-seq). We defined liver macrophages into four distinct subsets including monocyte-derived macrophages (MDMs) subset and three Kupffer cells (KCs) subsets (Gpnmbhigh KCs, Peam1high KCs, and Gpnmblow Pecam1low KCs). Particularly, we identified a novel Gpnmbhigh KCs subset as lipid-associated macrophage (LAM) with high expression of Trem2, CD63, and CD9. Interestingly, LAM showed a potential immunosuppressive characteristic by expressing anti-inflammatory genes IL-7R during the MDBs formation. Using contact and transwell co-culture systems, the released mtDNA from hepatocytes was found to induce the activation of inflammasome in macrophages. Furthermore, we revealed the damaged DNA could activate the NOD-like receptor family pyrin domain containing-3 (NLRP3) inflammasome and subsequently form apoptosis-associated speck-like protein containing a caspase recruit domain (ASC) specks of liver macrophages. Collectively, our results firstly revealed macrophage heterogeneity and inflammasome activation by mtDNA from injured liver during MDBs pathogenesis, providing crucial understanding of pathogenesis of chronic liver disease.

The liver sinusoid, mainly composed of liver sinusoidal endothelial cells, hepatic macrophages and hepatic stellate cells, shapes the hepatic vasculature and is key to maintaining liver homeostasis and function. During chronic liver disease (CLD), the function of sinusoidal cells is impaired, being directly involved in the progression of liver fibrosis, cirrhosis, and main clinical complications including portal hypertension and hepatocellular carcinoma. In addition to their roles in liver diseases pathobiology, sinusoidal cells' paracrine communication or cross-talk is being studied as a mechanism of disease but also as a remarkable target for treatment. The aim of this review is to gather current knowledge of intercellular signalling in the hepatic sinusoid during the progression of liver disease. We summarise studies developed in pre-clinical models of CLD, especially emphasizing those pathways characterized in human-based clinically relevant models. Finally, we describe pharmacological treatments targeting sinusoidal communication as promising options to treat CLD and its clinical complications.

Liver fibrosis is a pathological change characterized by excessive deposition of extracellular matrix caused by chronic liver injury, and the mechanisms underlying its development are associated with endothelial cell injury, inflammatory immune cell activation, and HSC activation. Furthermore, hepatic macrophages exhibit remarkable heterogeneity and hold central functions in the evolution of liver fibrosis, with different subgroups exerting dual effects of promotion and regression. Currently, targeted macrophage therapy for reversing hepatic fibrosis has been extensively studied and has shown promising prospects. In this review, we will discuss the dual role of macrophages in liver fibrosis and provide new insights into reversing liver fibrosis based on macrophages.

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer and one of the leading causes of cancer-related deaths worldwide due to limited treatment options. The tumor microenvironment (TME), which is usually immunosuppressive in HCC, appears to be a decisive factor for response to immunotherapy and strategies aimed at inducing a more inflamed TME hold promise to overcome resistance to immunotherapy. Within the TME, the interplay of various cell types determines whether immunotherapy is successful. Liver macrophages, in particular tumor associated macrophages (TAMs), are known to play a crucial role in tumor progression and represent potential future therapeutic targets. The presence of C-C motif chemokine receptor 2 (CCR2) expressing macrophages is known to be associated with pathogenic angiogenesis and bad prognosis for HCC patients. A recent study published in Cancer Research describes how immunosuppressive macrophages in the TME can be repolarized through targeting Signaling Lymphocyte Activation Molecule Family member 7 (SLAMF7)-regulated CC-chemokine ligand 2 (CCL2) signaling, which sensitizes HCC tumors to immunotherapy in a mouse model. This mini-review gives a brief overview about the current knowledge on SLAMF7 in the context of anti-cancer immunity and how the recent findings could be integrated into new therapeutic strategies for HCC.

Fibrosis, an excessive self-repair response, is an age-related pathological process that universally affects various major organs such as the heart, liver, kidney, and lungs. Continuous accumulation of pathological tissue fibrosis destroys structural integrity and causes loss of function, with consequent organ failure and increased mortality. Although some differences exist in the triggering mechanisms and pathophysiologic manifestations of organ-specific fibrosis, they usually share similar cascading responses and features, including chronic inflammatory stimulation, parenchymal cell injury, and macrophage recruitment. Macrophages, due to their high plasticity, can polarize into different phenotypes in response to varied microenvironments and play a crucial role in the development of organ fibrosis. This review examined the relationship between macrophages and the pathogenesis of organ fibrosis. Moreover, it analyzed how fibrosis can be modulated by targeting macrophages, which may become a novel and promising therapeutic strategy for fibrosis.

Liver injury releases danger-associated molecular patterns, which trigger the immune response. CD24 negatively regulates the immune response by binding with danger-associated molecular patterns, but the specific role of CD24 in modulating macrophage-related inflammation during liver injury remains largely unexplored. Here, we aimed to investigate the mechanisms of macrophage CD24 in the development of liver injury. Our results show that CD24 expression is upregulated primarily in hepatic macrophages (HMs) during acute liver injury. CD24-deficient mice exhibited more severe liver injury and showed a significantly higher frequency and number of HMs, particularly Ly6Chi monocyte-derived macrophages. Mechanistically, the CD24-Siglec-G interaction plays a vital role in mitigating acute liver injury. CD24-mediated inhibitory signaling in HMs primarily limits downstream NF-κB and p38 MAPK activation through the recruitment of SHP1. Our work unveils the critical role of macrophage CD24 in negatively regulating innate immune responses and protecting against acute liver injury, thus providing potential therapeutic targets for liver-associated diseases.

The liver is the predominant metastatic site for diverse cancers, including pancreatic and colorectal cancers (CRC), etc. The high incidence of hepatic metastasis of pancreatic cancer is an important reason for its refractory and high mortality. Therefore, it is important to understand how metastatic pancreatic cancer affects the hepatic tumor immune microenvironment (TME) in patients. Here, we characterized the TME of liver metastases unique to pancreatic cancer by comparing them with CRC liver metastases. We integrated two single-cell RNA-seq (scRNA-seq) datasets including tumor samples of pancreatic cancer liver metastasis (P-LM), colorectal cancer liver metastasis (C-LM), primary pancreatic cancer (PP), primary colorectal cancer (PC), as well as samples of peripheral blood mono-nuclear cells (PBMC), adjacent normal pancreatic tissues (NPT), to better characterize the heterogeneities of the microenvironment of two kinds of liver metastases. We next performed comparative analysis on cellular compositions between P-LM and C-LM, found that Mph_SPP1, a subset of macrophages associated with angiogenesis and tumor invasion, was more enriched in the P-LM group, indicating this kind of macrophages provide a TME niche more vulnerable for pancreatic cancers. Analysis of the developmental trajectory implied that Mph_SPP1 may progressively be furnished with increased expression of genes regulating endothelium. Cell-cell communications analysis revealed that Mph_SPP1 potentially interacts with endothelial cells in P-LM via FN1/SPP1-ITGAV/ITGB1, implying this macrophage subset may construct an immunosuppressive TME for pancreatic cancer by regulating endothelial cells. We also found that Mph_SPP1 has a prognostic value in pancreatic adenocarcinoma that is not present in colon adenocarcinoma or rectum adenocarcinoma. This study provides a new perspective for understanding the characteristics of the hepatic TME in patients with liver metastatic cancer. And it provides a subset of macrophages specifically associated with the liver metastasis of pancreatic cancer, and its detection and intervention have potential value for preventing the metastasis of pancreatic cancer to the liver.

The inflammatory macrophage response contributes to severe Ebola virus disease, with liver and lung injury in humans.

We sought to further define the activation status of hepatic and pulmonary macrophage populations in Ebola virus disease.

We compared liver and lung tissue from terminal Ebola virus (EBOV)-infected and uninfected control cynomolgus macaques challenged via the conjunctival route. Gene and protein expression was quantified using the nCounter and GeoMx Digital Spatial Profiling platforms. Macrophage phenotypes were further quantified by digital pathology analysis.

Hepatic macrophages in the EBOV-infected group demonstrated a mixed inflammatory/non-inflammatory profile, with upregulation of CD163 protein expression, associated with macrophage activation syndrome. Hepatic macrophages also showed differential expression of gene sets related to monocyte/macrophage differentiation, antigen presentation, and T cell activation, which were associated with decreased MHC-II allele expression. Moreover, hepatic macrophages had enriched expression of genes and proteins targetable with known immunomodulatory therapeutics, including S100A9, IDO1, and CTLA-4. No statistically significant differences in M1/M2 gene expression were observed in hepatic macrophages compared to controls. The significant changes that occurred in both the liver and lung were more pronounced in the liver.

These data demonstrate that hepatic macrophages in terminal conjunctivally challenged cynomolgus macaques may express a unique inflammatory profile compared to other macaque models and that macrophage-related pharmacologically druggable targets are expressed in both the liver and the lung in Ebola virus disease.

Overdose of acetaminophen (APAP), a commonly used antipyretic analgesic, can lead to severe liver injury and failure. Current treatments are only effective in the early stages of APAP-induced acute liver injury (ALI). Therefore, a detailed examination of the mechanisms involved in liver repair following APAP-induced ALI could provide valuable insights for clinical interventions.

4D-label-free proteomics analysis was used to identify dysregulated proteins in the liver of APAP-treated mice. RNA-Seq, hematoxylin-eosin staining, immunohistochemical staining, immunofluorescence staining, quantitative PCR, western blotting, transwell were used to explore the underlying mechanisms.

Utilizing high throughput 4D-label-free proteomics analysis, we observed a notable increase in proteins related to the "focal adhesion" pathway in the livers of APAP-treated mice. Inhibiting focal adhesion kinase (FAK) activation with a specific inhibitor, 1,2,4,5-Benzenetetraamine tetrahydrochloride (also called Y15), resulted in reduced macrophage numbers, delayed necrotic cell clearance, and inhibited liver cell proliferation in the necrotic regions of APAP-treated mice. RNA-Seq analysis demonstrated that Y15 downregulated genes associated with "cell cycle" and "phagosome" pathways in the livers of APAP-treated mice. Furthermore, blocking extracellular matrix (ECM)-integrin activation with a competitive peptide inhibitor, Gly-Arg-Gly-Asp-Ser (GRGDS), suppressed FAK activation and liver cell proliferation without affecting macrophage recruitment to necrotic areas. Mechanistically, ECM-induced FAK activation upregulated growth-promoting cell cycle genes, leading to hepatocyte proliferation, while CCL2 enhanced FAK activation and subsequent macrophage recruitment via F-actin rearrangement.

Overall, these findings underscore the pivotal role of FAK activation in liver repair post-APAP overdose by promoting liver cell proliferation and macrophage recruitment.

HCC, the most common type of primary liver cancer, is a leading cause of cancer-related mortality worldwide. Although the advancement of immunotherapies by immune checkpoint inhibitors (ICIs) that target programmed cell death 1 or programmed cell death 1-ligand 1 has revolutionized the treatment for HCC, the majority is still not beneficial. Accumulating evidence has pointed out that the potent immunosuppressive tumor microenvironment in HCC poses a great challenge to ICI therapeutic efficacy. As a key component in tumor microenvironment, tumor-associated macrophages (TAMs) play vital roles in HCC development, progression, and ICI low responsiveness. Mechanistically, TAM can promote cancer invasion and metastasis, angiogenesis, epithelial-mesenchymal transition, maintenance of stemness, and most importantly, immunosuppression. Targeting TAMs, therefore, represents an opportunity to enhance the ICI therapeutic efficacy in patients with HCC. While previous research has primarily focused on biochemical cues influencing macrophages, emerging evidence highlights the critical role of biophysical signals, such as substrate stiffness, topography, and external forces. In this review, we summarize the influence of biophysical characteristics within the tumor microenvironment that regulate the phenotype and function of TAMs in HCC pathogenesis and progression. We also explore the possible mechanisms and discuss the potential of manipulating biophysical cues in regulating TAM for HCC therapy. By gaining a deeper understanding of how macrophages sense and respond to mechanical forces, we may potentially usher in a path toward a curative approach for combinatory cancer immunotherapies.

Metabolic reprogramming is a pivotal biological process in which cellular metabolic patterns change to meet the energy demands of increased cell growth and proliferation. In this review, we explore metabolic reprogramming and its impact on fibrotic diseases, providing a detailed overview of the key processes involved in the metabolic reprogramming of renal fibrosis, including fatty acid decomposition and synthesis, glycolysis, and amino acid catabolism. In addition, we report that Chinese medicine ameliorates renal inflammation, oxidative stress, and apoptosis in chronic kidney disease by regulating metabolic processes, thereby inhibiting renal fibrosis. Furthermore, we reveal that multiple targets and signaling pathways contribute to the metabolic regulatory effects of Chinese medicine. In summary, this review aims to elucidate the mechanisms by which Chinese medicine inhibits renal fibrosis through the remodeling of renal cell metabolic processes, with the goal of discovering new therapeutic drugs for treating renal fibrosis.

Apical papilla stem cells (SCAPs) exhibit significant potential for tissue repair, characterized by their anti-inflammatory and pro-angiogenic properties. Exosomes derived from stem cells have emerged as safer alternatives that retain comparable physiological functions. This study explores the therapeutic potential of exosomes sourced from SCAPs in the treatment of non-alcoholic steatohepatitis (NASH).

A NASH mouse model was established through the administration of a high-fat diet (HFD), and SCAPs were subsequently isolated for experimental purposes. A cell model of NASH was established in vitro by treating hepatocellular carcinoma cells with oleic acid (OA) and palmitic acid (PA). Exosomes were isolated via differential centrifugation. The mice were treated with exosomes injected into the tail vein, and the hepatocytes were incubated with exosomes in vitro. After the experiment, physiological and biochemical markers were analyzed to assess the effects of exosomes derived from SCAPs on the progression of NASH in both NASH mouse models and NASH cell models.

After exosomes treatment, the weight gain and liver damage induced by HFD were significantly reduced. Additionally, hepatic fat accumulation was markedly alleviated. Mechanistically, exosomes treatment promoted the expression of genes involved in hepatic fatty acid oxidation and transport, while simultaneously suppressing genes associated with fatty acid synthesis. Furthermore, the levels of serum inflammatory cytokines and the mRNA expression of inflammatory markers in liver tissue were significantly decreased. In vitro cell experiments produced similar results.

Mesenchymal stem cells (MSCs) are highly effective in the treatment of acute liver failure (ALF). The efficacy of MSCs is closely related to the inflammatory environment. Therefore, we investigated the functional changes of MSCs in response to interleukin-33 (IL-33) stimulation. The results showed that bone marrow mesenchymal stem cells (BMSCs) pretreated with IL-33 had increased CCR2 expression, targeted CCL2 in the injured liver tissue, and improved the migration ability. Under LPS stimulation, the NF-κB pathway of BMDM was activated, and its phenotype polarized to the M1-type, while BMSCs pretreated with IL-33 inhibited the NF-κB pathway and enhanced M2 macrophage polarization. The M2-type macrophages could further inhibit hepatocytes inflammation, reduce hepatocytes apoptosis, and promote hepatocytes repair. These results suggest that IL-33 can enhance the efficacy of BMSCs in ALF and provide a new strategy for cell therapy of liver diseases.

Kidney inflammation plays a crucial role in the pathogenesis of IgA nephropathy (IgAN), yet the specific phenotypes of immune cells involved in disease progression remain incompletely understood. Utilizing joint profiling through longitudinal single-cell RNA-sequencing (scRNAseq) and single-cell assay for transposase-accessible chromatin sequencing (scATACseq) can provide a comprehensive framework for elucidating the development of cell subset diversity and how chromatin accessibility regulates transcription.

We aimed to characterize the dynamic immune cellular landscape at a high resolution in an early IgAN mouse model with acute kidney injury (AKI).

A murine model was utilized to mimic 3 immunological states -"immune stability (IS), immune activation (IA) and immune remission (IR)" in early human IgAN-associated glomerulopathy during AKI, achieved through lipopolysaccharide (LPS) injection. Urinary albumin to creatinine ratio (UACR) was measured to further validate the exacerbation and resolution of kidney inflammation during this course. Paired scRNAseq and scATACseq analysis was performed on CD45+ immune cells isolated from kidney tissues obtained from CTRL (healthy vehicle), IS, IA and IR (4 or 5 mice each). The analyses revealed 7 major cell types and 24 clusters based on 72304 single-cell transcriptomes, allowing for the identification and characterization of various immune cell types within each cluster. Our data offer an impartial depiction of the immunological characteristics, as the proportions of immune cell types fluctuated throughout different stages of the disease. Specifically, these analyses also revealed novel subpopulations, such as a macrophage subset (Nlrp1b Mac) with distinct epigenetic features and a unique transcription factor motif profile, potentially exerting immunoregulatory effects, as well as an early subset of Tex distinguished by their effector and cytolytic potential (CX3CR1-transTeff). Furthermore, in order to investigate the potential interaction between immune cells and renal resident cells, we conducted single-cell RNA sequencing on kidney cells obtained from a separate cohort of IS and IA mice without isolating immune cells. These findings underscored the diverse roles played by macrophages and CD8+ T cells in maintaining homeostasis of endothelial cells (ECs) under stress.

This study presents a comprehensive analysis of the dynamic changes in immune cell profiles in a model of IgAN, identifying key cell types and their roles and interactions. These findings significantly contribute to the understanding of the pathogenesis of IgAN and may provide potential targets for therapeutic intervention.

The tumor microenvironment (TME) is a dynamic system orchestrated by intricate cell-to-cell crosstalk. Specifically, macrophages within the TME play a crucial role in driving tumor progression. Exosomes are key mediators of communication between tumor cells and the TME. However, the mechanisms underlying exosome-driven crosstalk between tumor cells and macrophages during colorectal cancer (CRC) progression remain incompletely elucidated.

Single-cell RNA sequencing were analyzed using the Seurat package. Exosomes were isolated using ultracentrifugation and characterized by transmission electron microscopy, nanoparticle tracking analysis, and western blot. miRNAs differentially expressed in exosomes were analyzed using the limma package. CD206 expression in CRC tissues, exosomes tracing, and exosomal miR-106a-5p transport were observed through immunofluorescence. Macrophage polarization was assessed via qRT-PCR, ELISA, and flow cytometry. The interactions between miR-106a-5p, hnRNPA1, and SOCS6 were evaluated using miRNA pull-down, RIP, and dual-luciferase reporter assays. Transwell assays and liver metastasis model explored the role of exosomal miR-106a-5p-induced M2 macrophages in promoting CRC liver metastasis.

The proportion of M2 macrophages is increased in CRC with liver metastasis compared to those without. Highly metastatic CRC cells release exosomes enriched with miR-106a-5p, which promote macrophages M2 polarization by suppressing SOCS6 and activating JAK2/STAT3 pathway. These M2 macrophages reciprocally enhance CRC liver metastasis. hnRNPA1 regulate the transport of miR-106a-5p into exosomes. Clinically, elevated miR-106a-5p in plasma exosomes correlated with liver metastasis and poor prognosis.

CRC-derived exosomal miR-106a-5p plays a critical role in promoting liver metastasis and is a potential biomarker for the prevention and treatment of CRC liver metastasis.

The hepatic sinusoids are composed of liver sinusoidal endothelial cells (LSECs), which are surrounded by hepatic stellate cells (HSCs) and contain liver-resident macrophages called Kupffer cells, and other patrolling immune cells. All these cells communicate with each other and with hepatocytes to maintain sinusoidal homeostasis and a spectrum of hepatic functions under healthy conditions. Sinusoidal homeostasis is disrupted by metabolites, toxins, viruses, and other pathological factors, leading to liver injury, chronic liver diseases, and cirrhosis. Alterations in hepatic sinusoids are linked to fibrosis progression and portal hypertension. LSECs are crucial regulators of cellular crosstalk within their microenvironment via angiocrine signaling. This review discusses the mechanisms by which angiocrine signaling orchestrates sinusoidal homeostasis, as well as the development of liver diseases. Here, we summarise the crosstalk between LSECs, HSCs, hepatocytes, cholangiocytes, and immune cells in health and disease and comment on potential novel therapeutic methods for treating liver diseases.

Metabolic dysfunction-associated steatotic liver disease (MASLD) encompasses metabolic dysfunction-associated fatty liver (MASL) and metabolic dysfunction-associated steatohepatitis (MASH), with MASH posing a risk of progression to cirrhosis and hepatocellular carcinoma (HCC). The global prevalence of MASLD is estimated at approximately a quarter of the population, with significant healthcare costs and implications for liver transplantation. The pathogenesis of MASLD involves intrahepatic liver cells, extrahepatic components, and immunological aspects, particularly the involvement of macrophages. Hepatic macrophages are a crucial cellular component of the liver and play important roles in liver function, contributing significantly to tissue homeostasis and swift responses during pathophysiological conditions. Recent advancements in technology have revealed the remarkable heterogeneity and plasticity of hepatic macrophage populations and their activation states in MASLD, challenging traditional classification methods like the M1/M2 paradigm and highlighting the coexistence of harmful and beneficial macrophage phenotypes that are dynamically regulated during MASLD progression. This complexity underscores the importance of considering macrophage heterogeneity in therapeutic targeting strategies, including their distinct ontogeny and functional phenotypes. This review provides an overview of macrophage involvement in MASLD progression, combining traditional paradigms with recent insights from single-cell analysis and spatial dynamics. It also addresses unresolved questions and challenges in this area.

Liver fibrosis is the consequence of chronic liver injury in the presence of an inflammatory component. Although the main executors of this activation are known, the mechanisms that lead to the inflammatory process that mediates the production of pro-fibrotic factors are not well characterized. Epidermal growth factor receptor (EGFR) signaling in hepatocytes is essential for the regenerative processes of the liver; however, its potential role in regulating the fibrotic niche is not yet clear. Our group generated a mouse model that expresses an inactive truncated form of the EGFR specifically in hepatocytes (ΔEGFR mice). Here, we have analyzed the response of WT and ΔEGFR mice to chronic treatment with carbon tetrachloride (CCl4), which induces a pro-inflammatory and fibrotic process in the liver. The results indicated that the hallmarks of liver fibrosis were attenuated in CCl4-treated ΔEGFR mice when compared with CCl4-treated WT mice, coinciding with a faster resolution of the fibrotic process and ameliorated damage. The absence of EGFR activity in hepatocytes induced changes in the pattern of immune cells in the liver, with a notable increase in the population of M2 macrophages, more related to fibrosis resolution, as well as in the population of lymphocytes related to eradication of the damage. Transcriptome analysis of hepatocytes, and secretome studies of extracellular media from in vitro experiments, allowed us to elucidate the specific molecular mechanisms regulated by EGFR that mediate hepatocyte production of both pro-fibrotic and pro-inflammatory mediators; these have consequences for the deposition of extracellular matrix proteins, as well as for the immune microenvironment. Overall, our study uncovered novel mechanistic insights regarding EGFR kinase-dependent actions in hepatocytes that reveal its key role in chronic liver damage. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Persistent cholestasis has been associated with poor prognosis after orthotopic liver transplantation. In this study, we aimed to investigate how the accumulation of tauro-beta-muricholic acid (TβMCA), resulting from the reprogramming of bile acid (BA) metabolism during liver ischemia/reperfusion (IR) stress, attenuates liver inflammation.

Ingenuity Pathway Analysis was performed using transcriptome data from a murine hepatic IR model. Three different models of hepatic IR (liver warm IR, bile duct separation-IR, common bile duct ligation-IR) were employed. We generated adeno-associated virus-transfected mice and CD11b-DTR mice to assess the role of BAs in regulating the myeloid S1PR2-GSDMD axis. Hepatic BA levels were analyzed using targeted metabolomics. Finally, the correlation between the reprogramming of BA metabolism and hepatic S1PR2 levels was validated through RNA-seq of human liver transplant biopsies.

We found that BA metabolism underwent reprogramming in murine hepatocytes under IR stress, leading to increased synthesis of TβMCA, catalyzed by the enzyme CYP2C70. The levels of hepatic TβMCA were negatively correlated with the severity of hepatic inflammation, as indicated by the serum IL-1β levels. Inhibition of hepatic CYP2C70 resulted in reduced TβMCA production, which subsequently increased serum IL-1β levels and exacerbated IR injury. Moreover, our findings suggested that TβMCA could inhibit canonical inflammasome activation in macrophages and attenuate inflammatory responses in a myeloid-specific S1PR2-GSDMD-dependent manner. Additionally, Gly-βMCA, a derivative of TβMCA, could effectively attenuate inflammatory injury in vivo and inhibit human macrophage pyroptosis in vitro.

IR stress orchestrates hepatic BA metabolism to generate TβMCA, which attenuates hepatic inflammatory injury by inhibiting the myeloid S1PR2-GSDMD axis. Bile acids have immunomodulatory functions in liver reperfusion injury that may guide therapeutic strategies.

Our research reveals that liver ischemia-reperfusion stress triggers reprogramming of bile acid metabolism. This functions as an adaptive mechanism to mitigate inflammatory injury by regulating the S1PR2-GSDMD axis, thereby controlling the release of IL-1β from macrophages. Our results highlight the crucial role of bile acids in regulating hepatocyte-immune cell crosstalk, which demonstrates an immunomodulatory function in liver reperfusion injury that may guide therapeutic strategies targeting bile acids and their receptors.

Chronic liver diseases, primarily metabolic dysfunction-associated steatotic liver disease (MASLD), harmful use of alcohol, or viral hepatitis, may result in liver fibrosis, cirrhosis, and cancer. Hepatic fibrogenesis is a complex process with interactions between different resident and non-resident heterogeneous liver cell populations, ultimately leading to deposition of extracellular matrix and organ failure. Shifts in cell phenotypes and functions involve pronounced transcriptional and protein synthesis changes that require metabolic adaptations in cellular substrate metabolism, including glucose and lipid metabolism, resembling changes associated with the Warburg effect in cancer cells. Cell activation and metabolic changes are regulated by metabolic stress responses, including the unfolded protein response, endoplasmic reticulum stress, autophagy, ferroptosis, and nuclear receptor signaling. These metabolic adaptations are crucial for inflammatory and fibrogenic activation of macrophages, lymphoid cells, and hepatic stellate cells. Modulation of these pathways, therefore, offers opportunities for novel therapeutic approaches to halt or even reverse liver fibrosis progression.

The liver is a vital organ that continuously adapts to a wide and dynamic diversity of self-antigens and xenobiotics. This involves the active contribution of immune cells, particularly by the liver-resident macrophages, the Kupffer cells (KCs), which exert a variety of central functions in liver homeostasis and disease. As such, KCs interact with their microenvironment to shape the hepatic cellular landscape, control gut-derived signal integration, and modulate metabolism. On injury, the rapid recruitment of bone marrow monocyte-derived macrophages alters this status quo and, when unrestrained, drastically compromises liver homeostasis, immune surveillance, and tissue organization. Several factors determine the functional roles of liver macrophages in these processes, such as their ontogeny, activation/polarization profile and, importantly, spatial distribution within the liver. Loss of tolerance and adaptability of the hepatic immune environment may result in persistent inflammation, hepatic fibrosis, cirrhosis, and a tumorigenic niche promoting liver cancer. In this review, we aim at providing the most recent breakthroughs in our understanding of liver macrophage biology, particularly their diversity and adaptability in the hepatic spatiotemporal context, as well as on potential therapeutic interventions that may hold the key to tackling remaining clinical challenges of varying etiologies in hepatology.

Macrophage inhibitory factor (MIF) is a multipotent cytokine, involved in the inflammatory response to infections or injuries. This study investigates the role of MIF in liver fibrosis and the modulating effect of betaine on MIF in thioacetamide (TAA)-induced liver fibrosis. The wild-type and knockout MIF-/- C57BL/6 mice were divided into the following groups: control; Bet group, which received betaine; MIF-/-; MIF-/-+Bet; TAA group, which received TAA; TAA+Bet; MIF-/-+TAA; and MIF-/-+TAA+Bet group. After eight weeks of treatment, liver tissue was collected for further analysis. The results revealed that TAA-treated MIF-deficient mice had elevated levels of hepatic TGF-β1 and PDGF-BB, as well as MMP-2, MMP-9, and TIMP-1 compared to TAA-treated wild-type mice. However, the administration of betaine to TAA-treated MIF-deficient mice reduced hepatic TGF-β1 and PDGF-BB levels and also the relative activities of MMP-2, MMP-9 and TIMP-1, albeit less effectively than in TAA-treated mice without MIF deficiency. Furthermore, the antifibrogenic effect of MIF was demonstrated by an increase in MMP2/TIMP1 and MMP9/TIMP1 ratios. The changes in the hepatic levels of fibrogenic factors were confirmed by a histological examination of liver tissue. Overall, the dual nature of MIF highlights its involvement in the progression of liver fibrosis. Its prooxidant and proinflammatory effects may exacerbate tissue damage and inflammation initially, but its antifibrogenic activity suggests a potential protective role against fibrosis development. The study showed that betaine modulates the antifibrogenic effects of MIF in TAA-induced liver fibrosis, by decreasing TGF-β1, PDGF-BB, MMP-2, MMP-9, TIMP-1, and the deposition of ECM (Coll1 and Coll3) in the liver.

Brain disorders represent a significant challenge in medical science due to the formidable blood-brain barrier (BBB), which severely limits the penetration of conventional therapeutics, hindering effective treatment strategies. This review delves into the innovative realm of biomimetic nanodelivery systems, including stem cell-derived nanoghosts, tumor cell membrane-coated nanoparticles, and erythrocyte membrane-based carriers, highlighting their potential to circumvent the BBB's restrictions. By mimicking native cell properties, these nanocarriers emerge as a promising solution for enhancing drug delivery to the brain, offering a strategic advantage in overcoming the barrier's selective permeability. The unique benefits of leveraging cell membranes from various sources is evaluated and advanced technologies for fabricating cell membrane-encapsulated nanoparticles capable of masquerading as endogenous cells are examined. This enables the targeted delivery of a broad spectrum of therapeutic agents, ranging from small molecule drugs to proteins, thereby providing an innovative approach to neurocare. Further, the review contrasts the capabilities and limitations of these biomimetic nanocarriers with traditional delivery methods, underlining their potential to enable targeted, sustained, and minimally invasive treatment modalities. This review is concluded with a perspective on the clinical translation of these biomimetic systems, underscoring their transformative impact on the therapeutic landscape for intractable brain diseases.

Non-alcoholic fatty liver disease (NAFLD) presents as a common liver disease characterized by an indistinct pathogenesis. Disulfidptosis is a recently identified mode of cell death. This study aimed to investigate the potential role of disulfidptosis-related genes (DRGs) in the pathogenesis of NAFLD.

Gene expression profiles were obtained from the bulk RNA dataset GSE126848 and the single-cell RNA dataset GSE136103, both associated with NAFLD. Our study assessed the expression of DRGs in NAFLD and normal tissues. Weighted gene co-expression network analysis (WGCNA) and differential expression analysis were employed to identify the key NAFLD-specific differentially expressed DRGs (DE-DRGs). To explore the biological functions and immune regulatory roles of these key DE-DRGs, we conducted immune infiltration analysis, functional enrichment analysis, consensus clustering analysis, and single-cell differential state analysis. Finally, we validated the expression and biological functions of DRGs in NAFLD patients using histology and RNA-sequencing transcriptomic assays with human liver tissue samples.

Through the intersection of WGCNA, differentially expressed genes, and DRGs, two key DE-DRGs (DSTN and MYL6) were identified. Immune infiltration analysis indicated a higher proportion of macrophages, T cells, and resting dendritic cells in NAFLD compared to control liver samples. Based on the key DE-DRGs, Two disulfidptosis clusters were defined in GSE126848. Cluster 1, with higher expression of the key DE-DRGs, exhibited increased immune infiltration abundance and was closely associated with oxidative stress and immune regulation compared to cluster 2. High-resolution analysis of mononuclear phagocytes highlighted the potential role of MYL6 in intrahepatic M1 phenotype Kupffer cells in NAFLD patients. Our transcriptome data revealed that the expression levels of the majority of DRGs were significantly increased in NAFLD patients. NAFLD patients exhibit elevated MYL6 correlating with inflammation, oxidative stress, and disease severity, offering promising diagnostic specificity.

This comprehensive study provides evidence for the association between NAFLD and disulfidptosis, identifying potential target genes and pathways in NAFLD. The identification of MYL6 as a possible treatment target for NAFLD provided a novel understanding of the disease's development.

Interleukin (IL)-1β is an apex proinflammatory cytokine produced in response to tissue injury and infection. The output of IL-1β from monocytes and macrophages is regulated not only by transcription and translation but also post-translationally. Release of the active cytokine requires activation of inflammasomes, which couple IL-1β post-translational proteolysis with pyroptosis. Among inflammasome platforms, NOD-like receptor pyrin domain-containing protein 3 (NLRP3) is implicated in the pathogenesis of numerous human disorders in which disease-specific danger-associated molecular patterns (DAMPS) are positioned to drive its activation. As a promising therapeutic target, numerous candidate NLRP3-targeting therapeutics have been described and demonstrated to provide benefits in the context of animal disease models. While showing benefits, published preclinical studies have not explored dose-response relationships within the context of the models. Here, the preclinical pharmacology of a new chemical entity, [(1,2,3,5,6,7-hexahydro-s-indacen-4-yl)carbamoyl][(1-methyl-1H-pyrazol-4-yl)({[(2S)-oxolan-2-yl]methyl})sulfamoyl]azanide (NT-0249), is detailed, establishing its potency and selectivity as an NLRP3 inhibitor. NT-0249 also is evaluated in two acute in vivo mouse challenge models where pharmacodynamic/pharmacokinetic relationships align well with in vitro blood potency assessments. The therapeutic utility of NT-0249 is established in a mouse model of cryopyrin-associated periodic syndrome (CAPS). In this model, mice express a human gain-of-function NLRP3 allele and develop chronic and progressive IL-1β-dependent autoinflammatory disease. NT-0249 dose-dependently reduced multiple inflammatory biomarkers in this model. Significantly, NT-0249 decreased mature IL-1β levels in tissue homogenates, confirming in vivo target engagement. Our findings highlight not only the pharmacological attributes of NT-0249 but also provide insight into the extent of target suppression that will be required to achieve clinical benefit.

Liver cancer is one of the leading causes of cancer-related mortality. Hepatocellular carcinoma and cholangiocarcinoma are the most common types, and despite numerous advances, therapeutic options still remain poor for these cancer patients. Tumor development and progression strictly depend on a supportive tumor microenvironment (TME). Tumor-associated macrophages (TAMs) are the most abundant immune cells population within a tumorigenic liver; they sustain cancer cells' growth and invasiveness, and their presence is correlated with a poor prognosis. Furthermore, TAM cross-talk with cells and components of the TME promotes immunosuppression, a desmoplastic response, and angiogenesis. In this review, we summarize the latest advances in understanding TAM heterogeneity and function, with a particular focus on TAM modulation of the TME. We also discuss the potential of targeting macrophage subpopulations and how this is now being exploited in current clinical trials for the treatment of liver cancer.

Chronic liver diseases, such as non-alcoholic steatohepatitis (NASH)-induced cirrhosis, are characterized by an increasing accumulation of stressed, damaged, or dying hepatocytes. Hepatocyte damage triggers the activation of resident immune cells, such as Kupffer cells (KC), as well as the recruitment of immune cells from the circulation toward areas of inflammation. After infiltration, monocytes differentiate into monocyte-derived macrophages (MoMF) which are functionally distinct from resident KC. We herein aim to compare the in vitro signatures of polarized macrophages and activated hepatic stellate cells (HSC) with ex vivo-derived disease signatures from human NASH. Furthermore, to shed more light on HSC activation and liver fibrosis progression, we investigate the effects of the secretome from primary human monocytes, macrophages, and NK cells on HSC activation. Interleukin (IL)-4 and IL-13 treatment induced transforming growth factor beta 1 (TGF-β1) secretion by macrophages. However, the supernatant transfer did not induce HSC activation. Interestingly, PMA-activated macrophages showed strong induction of the fibrosis response genes COL10A1 and CTGF, while the supernatant of IL-4/IL-13-treated monocytes induced the upregulation of COL3A1 in HSC. The supernatant of PMA-activated NK cells had the strongest effect on COL10A1 induction in HSC, while IL-15-stimulated NK cells reduced the expression of COL1A1 and CTGF. These data indicate that other factors, aside from the well-known cytokines and chemokines, might potentially be stronger contributors to the activation of HSCs and induction of a fibrotic response, indicating a more diverse and complex role of monocytes, macrophages, and NK cells in liver fibrosis progression.

Acute-on-chronic liver failure (ACLF) is a progressive disease that is associated with rapid worsening of clinical symptoms and high mortality. A multicentre prospective study from China demonstrated that patients with hepatitis B virus-related ACLF (HBV-ACLF) exhibited worse clinical characteristics and higher mortality rates compared to non-HBV-ACLF patients. Immune dysregulation is closely linked to the potential mechanisms of initiation and progression of ACLF. Innate immune response, which is represented by monocytes/macrophages, is up-regulated across ACLF development. This suggests that monocytes/macrophages play an essential role in maintaining the immune homeostasis of ACLF. Information that has been published in recent years shows that the immune status and function of monocytes/macrophages vary in ACLF precipitated by different chronic liver diseases. Monocytes/macrophages have an immune activation effect in hepatitis B-precipitated-ACLF, but they exhibit an immune suppression in cirrhosis-precipitated-ACLF. Therefore, this review aims to explain whether this difference affects the clinical outcome in HBV-ACLF patients as well as the mechanisms involved. We summarize the novel findings that highlight the dynamic polarization phenotype and functional status of hepatic macrophages from the stage of HBV infection to ACLF development. Moreover, we discuss how different HBV-related liver disease tissue microenvironments affect the phenotype and function of hepatic macrophages. In summary, increasing developments in understanding the differences in immune phenotype and functional status of hepatic macrophages in ACLF patients will provide new perspectives towards the effective restoration of ACLF immune homeostasis.

Macrophages play a critical role in innate immunity, with approximately 90% of the total macrophage population in the human body residing in the liver. This population encompasses both resident and infiltrating macrophages. Recent studies highlight the pivotal role of liver macrophages in various aspects such as liver inflammation, regeneration, and immune regulation. A novel pro-inflammatory programmed cell death, pyroptosis, initially identified in macrophages, has garnered substantial attention since its discovery. Studies investigating pyroptosis and inflammation progression have particularly centered around macrophages. In liver diseases, pyroptosis plays an important role in driving the inflammatory response, facilitating the fibrotic process, and promoting tumor progression. Notably, the role of macrophage pyroptosis cannot be understated. This review primarily focuses on the role of macrophage pyroptosis in liver diseases. Additionally, it underscores the therapeutic potential inherent in targeting macrophage pyroptosis.

Liver fibrosis, as an excess deposition of extracellular matrix (ECM) components, results from chronic liver injury as well as persistent activation of inflammatory response and of fibrogenesis. Liver fibrosis is a major determinant for chronic liver disease (CLD) progression and in the last two decades our understanding on the major molecular and cellular mechanisms underlying the fibrogenic progression of CLD has dramatically improved, boosting pre-clinical studies and clinical trials designed to find novel therapeutic approaches. From these studies several critical concepts have emerged, starting to reveal the complexity of the pro-fibrotic microenvironment which involves very complex, dynamic and interrelated interactions between different hepatic and extrahepatic cell populations. This review will offer first a recapitulation of established and novel pathophysiological basic principles and concepts by intentionally focus the attention on NAFLD/NASH, a metabolic-related form of CLD with a high impact on the general population and emerging as a leading cause of CLD worldwide. NAFLD/NASH-related pro-inflammatory and profibrogenic mechanisms will be analysed as well as novel information on cells, mediators and signalling pathways which have taken advantage from novel methodological approaches and techniques (single cell genomics, imaging mass cytometry, novel in vitro two- and three-dimensional models, etc.). We will next offer an overview on recent advancement in diagnostic and prognostic tools, including serum biomarkers and polygenic scores, to support the analysis of liver biopsies. Finally, this review will provide an analysis of current and emerging therapies for the treatment of NAFLD/NASH patients.