RESUMO
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.
Assuntos
Células de Kupffer , Fígado , Humanos , Fígado/imunologia , Fígado/patologia , Células de Kupffer/imunologia , Células de Kupffer/fisiologia , Animais , Macrófagos/imunologia , Macrófagos/fisiologia , Homeostase/imunologiaRESUMO
Introduction: Sepsis is a life-threatening inflammatory condition caused by dysregulated host responses to infection. Extracellular cold-inducible RNA-binding protein (eCIRP) is a recently discovered damage-associated molecular pattern that causes inflammation and organ injury in sepsis. Kupffer cells can be activated and polarized to the inflammatory M1 phenotype, contributing to tissue damage by producing proinflammatory mediators. We hypothesized that eCIRP promotes Kupffer cell M1 polarization in sepsis. Methods: We stimulated Kupffer cells isolated from wild-type (WT) and TLR4-/- mice with recombinant mouse (rm) CIRP (i.e., eCIRP) and assessed supernatant IL-6 and TNFα levels by ELISA. The mRNA expression of iNOS and CD206 for M1 and M2 markers, respectively, was assessed by qPCR. We induced sepsis in WT and CIRP-/- mice by cecal ligation and puncture (CLP) and assessed iNOS and CD206 expression in Kupffer cells by flow cytometry. Results: eCIRP dose- and time-dependently increased IL-6 and TNFα release from WT Kupffer cells. In TLR4-/- Kupffer cells, their increase after eCIRP stimulation was prevented. eCIRP significantly increased iNOS gene expression, while it did not alter CD206 expression in WT Kupffer cells. In TLR4-/- Kupffer cells, however, iNOS expression was significantly decreased compared with WT Kupffer cells after eCIRP stimulation. iNOS expression in Kupffer cells was significantly increased at 20 h after CLP in WT mice. In contrast, Kupffer cell iNOS expression in CIRP-/- mice was significantly decreased compared with WT mice after CLP. CD206 expression in Kupffer cells was not different across all groups. Kupffer cell M1/M2 ratio was significantly increased in WT septic mice, while it was significantly decreased in CIRP-/- mice compared to WT mice after CLP. Conclusion: Our data have clearly shown that eCIRP induces Kupffer cell M1 polarization via TLR4 pathway in sepsis, resulting in overproduction of inflammatory cytokines. eCIRP could be a promising therapeutic target to attenuate inflammation by preventing Kupffer cell M1 polarization in sepsis.
Assuntos
Células de Kupffer , Camundongos Knockout , Proteínas de Ligação a RNA , Sepse , Animais , Células de Kupffer/imunologia , Células de Kupffer/metabolismo , Sepse/imunologia , Sepse/metabolismo , Camundongos , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Camundongos Endogâmicos C57BL , Receptor 4 Toll-Like/metabolismo , Receptor 4 Toll-Like/genética , Masculino , Óxido Nítrico Sintase Tipo II/metabolismo , Óxido Nítrico Sintase Tipo II/genética , Modelos Animais de Doenças , Inflamação/imunologia , Inflamação/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Receptor de Manose , Interleucina-6/metabolismoRESUMO
Miyamoto et al. report that Marco expression demarcates a population of IL-10-expressing immunosuppressive Kupffer cells (KCs) that are preferentially peri-portally located in the mouse liver, and which limit bacterial dissemination and liver inflammation.
Assuntos
Interleucina-10 , Células de Kupffer , Fígado , Animais , Células de Kupffer/imunologia , Camundongos , Fígado/imunologia , Fígado/patologia , Interleucina-10/metabolismo , Interleucina-10/imunologia , Humanos , Macrófagos/imunologia , Inflamação/imunologia , Receptores Imunológicos/metabolismo , Receptores Imunológicos/imunologiaRESUMO
Obesity-induced chronic low-grade inflammation, also known as metaflammation, results from alterations of the immune response in metabolic organs and contributes to the development of fatty liver diseases and type 2 diabetes. The diversity of tissue-resident leukocytes involved in these metabolic dysfunctions warrants an in-depth immunophenotyping in order to elucidate disease etiology. Here, we present a 30-color, full spectrum flow cytometry panel, designed to (i) identify the major innate and adaptive immune cell subsets in murine liver and white adipose tissues and (ii) discriminate various tissue-specific myeloid subsets known to contribute to the development of metabolic dysfunctions. This panel notably allows for distinguishing embryonically-derived liver-resident Kupffer cells from newly recruited monocyte-derived macrophages and KCs. Furthermore, several adipose tissue macrophage (ATM) subsets, including perivascular macrophages, lipid-associated macrophages, and pro-inflammatory CD11c+ ATMs, can also be identified. Finally, the panel includes cell-surface markers that have been associated with metabolic activation of different macrophage and dendritic cell subsets. Altogether, our spectral flow cytometry panel allows for an extensive immunophenotyping of murine metabolic tissues, with a particular focus on metabolically-relevant myeloid cell subsets, and can easily be adjusted to include various new markers if needed.
Assuntos
Citometria de Fluxo , Imunofenotipagem , Fígado , Macrófagos , Animais , Citometria de Fluxo/métodos , Camundongos , Macrófagos/imunologia , Macrófagos/metabolismo , Imunofenotipagem/métodos , Fígado/imunologia , Fígado/metabolismo , Camundongos Endogâmicos C57BL , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Células Dendríticas/citologia , Células de Kupffer/imunologia , Células de Kupffer/metabolismo , Inflamação/imunologia , Inflamação/patologia , Tecido Adiposo Branco/metabolismo , Tecido Adiposo Branco/imunologia , MasculinoRESUMO
Macrophage activation is controlled by a balance between activating and inhibitory receptors1-7, which protect normal tissues from excessive damage during infection8,9 but promote tumour growth and metastasis in cancer7,10. Here we report that the Kupffer cell lineage-determining factor ID3 controls this balance and selectively endows Kupffer cells with the ability to phagocytose live tumour cells and orchestrate the recruitment, proliferation and activation of natural killer and CD8 T lymphoid effector cells in the liver to restrict the growth of a variety of tumours. ID3 shifts the macrophage inhibitory/activating receptor balance to promote the phagocytic and lymphoid response, at least in part by buffering the binding of the transcription factors ELK1 and E2A at the SIRPA locus. Furthermore, loss- and gain-of-function experiments demonstrate that ID3 is sufficient to confer this potent anti-tumour activity to mouse bone-marrow-derived macrophages and human induced pluripotent stem-cell-derived macrophages. Expression of ID3 is therefore necessary and sufficient to endow macrophages with the ability to form an efficient anti-tumour niche, which could be harnessed for cell therapy in cancer.
Assuntos
Proteínas Inibidoras de Diferenciação , Células de Kupffer , Neoplasias , Animais , Humanos , Camundongos , Células da Medula Óssea/citologia , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , Linhagem da Célula , Células-Tronco Pluripotentes Induzidas/citologia , Proteínas Inibidoras de Diferenciação/deficiência , Proteínas Inibidoras de Diferenciação/genética , Proteínas Inibidoras de Diferenciação/metabolismo , Células Matadoras Naturais/citologia , Células Matadoras Naturais/imunologia , Células de Kupffer/citologia , Células de Kupffer/imunologia , Células de Kupffer/metabolismo , Fígado/imunologia , Fígado/patologia , Ativação de Macrófagos , Proteínas de Neoplasias , Neoplasias/imunologia , Neoplasias/patologia , Neoplasias/terapia , FagocitoseRESUMO
Macrophage aggregates step in to capture blood-borne pathogens in the injured liver.
Assuntos
Infecções Transmitidas por Sangue , Patógenos Transmitidos pelo Sangue , Células de Kupffer , Cirrose Hepática , Fígado , Animais , Camundongos , Infecções Transmitidas por Sangue/imunologia , Células de Kupffer/imunologia , Fígado/imunologia , Fígado/microbiologia , Cirrose Hepática/imunologia , Cirrose Hepática/microbiologia , Cirrose Hepática/patologia , HumanosRESUMO
Kupffer cells (KCs) are localized in liver sinusoids but extend pseudopods to parenchymal cells to maintain their identity and serve as the body's central bacterial filter. Liver cirrhosis drastically alters vascular architecture, but how KCs adapt is unclear. We used a mouse model of liver fibrosis and human tissue to examine immune adaptation. Fibrosis forced KCs to lose contact with parenchymal cells, down-regulating "KC identity," which rendered them incapable of clearing bacteria. Commensals stimulated the recruitment of monocytes through CD44 to a spatially distinct vascular compartment. There, recruited monocytes formed large aggregates of multinucleated cells (syncytia) that expressed phenotypical KC markers and displayed enhanced bacterial capture ability. Syncytia formed via CD36 and were observed in human cirrhosis as a possible antimicrobial defense that evolved with fibrosis.
Assuntos
Infecções Transmitidas por Sangue , Células Gigantes , Células de Kupffer , Cirrose Hepática , Animais , Humanos , Camundongos , Células Gigantes/imunologia , Células Gigantes/microbiologia , Células de Kupffer/imunologia , Células de Kupffer/microbiologia , Cirrose Hepática/imunologia , Cirrose Hepática/microbiologia , Cirrose Hepática/patologia , Infecções Transmitidas por Sangue/imunologia , Modelos Animais de DoençasRESUMO
Due to a combination of rapid disease progression and the lack of curative treatment options, hepatocellular carcinoma (HCC) is one of the deadliest cancers worldwide. Infiltrated, monocyte-derived, tumor-associated macrophages are known to play a role in HCC pathogenesis, but the involvement of Kupffer cells (KCs) remains elusive. Here, we used the Clec4F-diphteria toxin receptor transgenic mouse model to specifically investigate the effect of KC depletion on HCC initiation, progression and neoplastic growth following liver resection. For this purpose, several HCC mouse models with varying underlying etiologies were used and partial hepatectomy was performed. Our results show that in HCC, developed on a fibrotic or non-alcoholic steatohepatitis background, depletion of embryonic KCs at the onset of HCC induction and the subsequent replacement by monocyte-derived KCs does not affect the tumor burden, tumor microenvironment or the phenotype of isolated KCs at end-stage disease. In non-chronic liver disease-associated diethylnitrosamine-induced HCC, ablation of Clec4F+ KCs did not alter tumor progression or neoplastic growth following liver resection. Our results show that temporal ablation of resident KCs does not impact HCC pathogenesis, neither in the induction phase nor in advanced disease, and indicate that bone marrow-derived KCs are able to swiftly repopulate the available KC niche and adopt their phenotype.
Assuntos
Carcinogênese , Carcinoma Hepatocelular , Células de Kupffer , Neoplasias Hepáticas Experimentais , Neoplasias Hepáticas , Macrófagos Associados a Tumor , Células de Kupffer/imunologia , Progressão da Doença , Carcinoma Hepatocelular/imunologia , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/imunologia , Neoplasias Hepáticas/patologia , Macrófagos Associados a Tumor/imunologia , Macrófagos Associados a Tumor/patologia , Animais , Camundongos , Neoplasias Hepáticas Experimentais/imunologia , Neoplasias Hepáticas Experimentais/patologia , Células Precursoras de Monócitos e Macrófagos/imunologia , Carcinogênese/imunologia , Carcinogênese/patologia , Camundongos Endogâmicos C57BL , MasculinoRESUMO
Kupffer cells (KCs), the largest tissue-resident macrophage population in the body, play a central role in maintaining a delicate balance between immune tolerance and immunity in the liver. However, the underlying molecular mechanism remains elusive. In this study, we show that KCs express high levels of miR-146a, which is under control of the PU.1 transcription factor. miR-146a deficiency promoted KCs differentiation toward a proinflammatory phenotype; conversely, miR-146a overexpression suppressed this phenotypic differentiation. We found that hepatitis B virus (HBV) persistence or HBV surface Ag treatment significantly upregulated miR-146a expression and thereby impaired polarization of KCs toward a proinflammatory phenotype. Furthermore, in an HBV carrier mouse model, KCs depletion by clodronate liposomes dramatically promoted HBV clearance and enhanced an HBV-specific hepatic CD8+ T cell and CD4+ T cell response. Consistent with this finding, miR-146a knockout mice cleared HBV faster and elicited a stronger adaptive antiviral immunity than wild-type mice. In vivo IL-12 blockade promoted HBV persistence and tempered the HBV-specific CTL response in the liver of miR-146a knockout mice. Taken together, our results identified miR-146a as a critical intrinsic regulator of an immunosuppressive phenotype in KCs under inflammatory stimuli, which may be beneficial in maintenance of liver homeostasis under physiological condition. Meanwhile, during HBV infection, miR-146a contributed to viral persistence by inhibiting KCs proinflammatory polarization, highlighting its potential as a therapeutic target in HBV infection.
Assuntos
Hepatite B , Tolerância Imunológica , Células de Kupffer , MicroRNAs , Animais , Hepatite B/imunologia , Vírus da Hepatite B , Células de Kupffer/imunologia , Camundongos , Camundongos Knockout , MicroRNAs/genéticaRESUMO
The role of non-parenchymal liver cells as part of the hepatic, innate immune system in the defense against hepatotropic viruses is not well understood. Here, primary human Kupffer cells, liver sinusoidal endothelial cells and hepatic stellate cells were isolated from liver tissue obtained after tumor resections or liver transplantations. Cells were stimulated with Toll-like receptor 1-9 ligands for 6-24 h. Non-parenchymal liver cells expressed and secreted inflammatory cytokines (IL6, TNF and IL10). Toll-like receptor- and cell type-specific downstream signals included the phosphorylation of NF-κB, AKT, JNK, p38 and ERK1/2. However, only supernatants of TLR3-activated Kupffer cells, liver sinusoidal endothelial cells and hepatic stellate cells contained type I and type III interferons and mediated an antiviral activity in the interferon-sensitive subgenomic hepatitis C virus replicon system. The antiviral effect could not be neutralized by antibodies against IFNA, IFNB nor IFNL, but could be abrogated using an interferon alpha receptor 2-specific neutralization. Interestingly, TLR3 responsiveness was enhanced in liver sinusoidal endothelial cells isolated from hepatitis C virus-positive donors, compared to uninfected controls. In conclusion, non-parenchymal liver cells are potent activators of the hepatic immune system by mediating inflammatory responses. Furthermore, liver sinusoidal endothelial cells were identified to be hyperresponsive to viral stimuli in chronic hepatitis C virus infection.
Assuntos
Hepacivirus/fisiologia , Hepatite C Crônica/imunologia , Receptor 3 Toll-Like/imunologia , Animais , Células Endoteliais/imunologia , Células Endoteliais/virologia , Hepacivirus/genética , Hepacivirus/imunologia , Células Estreladas do Fígado/imunologia , Células Estreladas do Fígado/virologia , Hepatite C Crônica/genética , Hepatite C Crônica/virologia , Humanos , Interferons/genética , Interferons/imunologia , Interleucina-10/genética , Interleucina-10/imunologia , Interleucina-6/genética , Interleucina-6/imunologia , Células de Kupffer/imunologia , Células de Kupffer/virologia , Fígado/imunologia , Fígado/virologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Receptor 3 Toll-Like/genética , Receptores Toll-Like/genética , Receptores Toll-Like/imunologiaRESUMO
BACKGROUND & AIMS: Hepatocellular carcinoma (HCC) is characterized by intratumoral accumulation of regulatory T cells (Tregs), which suppresses antitumor immunity. This study was designed to investigate how microRNAs regulate immunosuppression in HCC. METHODS: FVB/NJ mice were hydrodynamically injected with AKT/Ras or c-Myc and Sleeping Beauty transposon to induce HCC. The Sleeping Beauty system was used to deliver microRNA-15a/16-1 into livers of mice. Flow cytometry and immunostaining were used to determine changes in the immune system. RESULTS: Hydrodynamic injection of AKT/Ras or c-Myc into mice resulted in hepatic enrichment of Tregs and reduced cytotoxic T cells (CTLs) and HCC development. HCC impaired microRNA-15a/16-1 biogenesis in Kupffer cells (KCs) of AKT/Ras and c-Myc mice. Hydrodynamic injection of microRNA-15a/16-1 fully prevented HCC in AKT/Ras and c-Myc mice, while 100% of control mice died of HCC. Therapeutically, microRNA-15a/16-1 promoted a regression of HCC in both mouse models, impaired hepatic enrichment of Tregs, and increased hepatic CTLs. Mechanistically, a significant increase was observed in serum C-C motif chemokine 22 (CCL22) and transcription of Ccl22 in KCs of AKT/Ras and c-Myc mice. MicroRNA-15a/16-1 prevented KCs from overproducing CCL22 by inhibiting nuclear factor-κB that activates transcription of Ccl22. By reducing CCL22 binding to C-C chemokine receptor type 4 on Tregs, microRNA-15a/16-1 impaired Treg chemotaxis. Disrupting the interaction between microRNA-15a/16-1 and nuclear factor-κB impaired the ability of microRNA-15a/16-1 to prevent hepatic Treg accumulation and HCC. Depletion of cluster of differentiation 8+ T cells and additional treatment of CCL22 recovered growth of HCC that was fully prevented by microRNA-15a/16. CONCLUSIONS: MicroRNA-15a/16-1 attenuates immunosuppression by disrupting CCL22-mediated communication between KCs and Tregs. MicroRNA-15a/16-1 represents a potential immunotherapy against HCC.
Assuntos
Carcinoma Hepatocelular/imunologia , Células de Kupffer/imunologia , Neoplasias Hepáticas Experimentais/imunologia , MicroRNAs/genética , Linfócitos T Reguladores/imunologia , Evasão Tumoral/imunologia , Animais , Carcinoma Hepatocelular/genética , Células de Kupffer/metabolismo , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/imunologia , Neoplasias Hepáticas Experimentais/genética , Camundongos , Proteínas Proto-Oncogênicas c-akt , Proteínas Proto-Oncogênicas c-myc , Linfócitos T Reguladores/metabolismo , Evasão Tumoral/genética , Proteínas rasRESUMO
Many of the effector functions of antibodies rely on the binding of antibodies/immune complexes to cellular Fcγ receptors (FcγRs). Since the majority of innate immune effector cells express both activating and inhibitory Fc receptors, the outcome of the binding of immune complexes to cells of a given population is influenced by the relative affinities of the respective IgG subclasses to these receptors, as well as by the numbers of activating and inhibitory FcγRs on the cell surface. A group of immune cells that has come into focus more recently is the various subsets of tissue-resident macrophages. The central functions of FcγRs on tissue macrophages include the clearance of opsonized pathogens, the removal of small immune complexes from the circulation and the depletion of antibody-opsonized cells in the therapy of autoimmunity and cancer. Despite these essential functions of FcγRs on tissue-resident macrophages, an in-depth quantification of FcγRs is lacking. Thus, the aim of our current study was to quantify the various Fcγ receptors on macrophages in murine liver, lung, kidney, brain, skin and spleen. Our study identified a pronounced heterogeneity between FcγR expression patterns of the different tissue macrophages, which may reflect their specialized functions within their unique niches in different organ environments.
Assuntos
Macrófagos/imunologia , Macrófagos/metabolismo , Receptores de IgG/imunologia , Receptores de IgG/metabolismo , Animais , Biomarcadores/metabolismo , Feminino , Rim/imunologia , Rim/metabolismo , Células de Kupffer/imunologia , Células de Kupffer/metabolismo , Pulmão/imunologia , Pulmão/metabolismo , Camundongos , Microglia/imunologia , Microglia/metabolismo , Receptores de IgG/análise , Pele/imunologia , Pele/metabolismo , Baço/imunologia , Baço/metabolismoRESUMO
This study is to investigate the effect of microRNA-1338 (miR-1338) on the activity of Kupffer cells (KCs) and its mechanism regulated by ophiopogon polysaccharide liposome (OPL). KCs was treated with different OPL after transfected with miR-1338 mimic and miR-1338 inhibitor. The secretion of NO and iNOS, the expression of catalase (CAT) and peroxidase (POD), the phagocytic activity, the expression of CD14 and MHC II, the apoptosis and the secretion of ROS were measured. In addition, the expressions of key signal factors TLR4, IKKß, MyD88 and NF-κB in NF-κB signaling pathway were measured by real-time PCR and Western blot (WB). The results showed that OPL could promote the secretion of iNOS, the expression of POD, the phagocytosis, the mRNA expression of TLR4, MyD88, IKKß and NF-κB, the protein expression of TLR4 and NF-κB, and inhibit the cell apoptosis and ROS secretion after transfected with miR-1338 mimic. After transfected with miR-1338 inhibitor, OPL could promote the secretion of NO and iNOS, the expression of POD, cell migration, phagocytosis, and inhibit cell apoptosis. Meanwhile, the mRNA expression of TLR4, MyD88, IKKß and NF-κB and the protein expression of TLR4, MyD88 and NF-κB were promoted. These results suggested that OPL could activate TLR4-NF-κB signaling pathway and thereby improve the activity of KCs by regulating miR-1338.
Assuntos
Fatores Imunológicos , Células de Kupffer/imunologia , MicroRNAs/imunologia , Ophiopogon/química , Polissacarídeos , Animais , Fatores Imunológicos/química , Fatores Imunológicos/farmacologia , Lipossomos , Camundongos , Polissacarídeos/química , Polissacarídeos/farmacologiaRESUMO
HCV core protein is the first structural protein synthesized during hepatitis C virus (HCV) infection and replication. It is released from virus infected liver cells and mediates multiple functions to affect host cell response. The innate immune response is the first line of defense against viral infection. After HCV infection, Kupffer cells (KCs) which are liver macrophages play an important role in host innate immune response. Kupffer cells act as phagocytes and release different cytokines and chemokines to counter viral infection and regulate inflammation and fibrosis in liver. Earlier, we have demonstrated that HCV core protein interacts with gC1qR and activates MAPK, NF-κB and PI3K/AKT pathways in macrophages. In this study, we explored the effect of HCV core protein on CCL2 and CXCL10 expression in macrophages and the signaling pathways involved. Upon silencing of gC1qR, we observed a significant decrease expression of CCL2 and CXCL10 in macrophages in the presence of HCV core protein. Inhibiting NF-κB pathway, but not P38, JNK, ERK and AKT pathways greatly reduced the expression of CCL2 and CXCL10. Therefore, our results indicate that interaction of HCV core protein with gC1qR could induce CCL2 and CXCL10 secretion in macrophages via NF-κB signaling pathway. These findings may shed light on the understanding of how leukocytes migrate into the liver and exaggerate host-derived immune responses and may provide novel therapeutic targets in HCV chronic inflammation.
Assuntos
Quimiocina CCL2/imunologia , Quimiocina CXCL10/imunologia , Hepacivirus/imunologia , Macrófagos/imunologia , NF-kappa B/imunologia , Transdução de Sinais/imunologia , Proteínas do Core Viral/imunologia , Animais , Células Cultivadas , Quimiocina CCL2/genética , Quimiocina CCL2/metabolismo , Quimiocina CXCL10/genética , Quimiocina CXCL10/metabolismo , Expressão Gênica/imunologia , Hepacivirus/metabolismo , Hepacivirus/fisiologia , Hepatite C/imunologia , Hepatite C/metabolismo , Hepatite C/virologia , Interações Hospedeiro-Patógeno/imunologia , Humanos , Células de Kupffer/imunologia , Células de Kupffer/metabolismo , Células de Kupffer/virologia , Macrófagos/metabolismo , Macrófagos/virologia , Camundongos , Camundongos Endogâmicos BALB C , Células RAW 264.7 , Células THP-1 , Proteínas do Core Viral/metabolismoRESUMO
OBJECTIVES: The discrepancy between supply and demand of organ has led to an increased utilization of steatotic liver for liver transplantation (LT). Hepatic steatosis, however, is a major risk factor for graft failure due to increased susceptibility to ischaemia-reperfusion (I/R) injury during transplantation. MATERIALS AND METHODS: To assess the plasticity and phenotype of immune cells within the microenvironment of steatotic liver graft at single-cell level, single-cell RNA-sequencing (scRNA-Seq) was carried out on 23 675 cells from transplanted rat livers. Bioinformatic analyses and multiplex immunohistochemistry were performed to assess the functional properties, transcriptional regulation, phenotypic switching and cell-cell interactions of different cell subtypes. RESULTS: We have identified 11 different cell types in transplanted livers and found that the highly complex ecosystem was shaped by myeloid-derived cell subsets that transit between different states and interact mutually. Notably, a pro-inflammatory phenotype of Kupffer cells (KCs) with high expression of colony-stimulating factor 3 (CSF3) that was enriched in transplanted steatotic livers was potentially participated in fatty graft injury. We have also detected a subset of dendritic cells (DCs) with highly expressing XCR1 that was correlated with CD8+ T cells, mediating the severer steatotic liver damage by I/R injury. CONCLUSIONS: The findings of our study provide new insight into the mechanisms by which steatosis exacerbates liver damage from I/R injury. Interventions based on these observations create opportunities in attenuating fatty liver graft injury and expanding the donor pool.
Assuntos
Fígado Gorduroso/imunologia , Fígado/imunologia , Traumatismo por Reperfusão/imunologia , Animais , Linfócitos T CD8-Positivos/imunologia , Comunicação Celular/imunologia , Modelos Animais de Doenças , Células de Kupffer/imunologia , Transplante de Fígado/métodos , Fenótipo , Ratos , Ratos Sprague-Dawley , Análise de Célula Única/métodos , Transcrição Gênica/imunologiaRESUMO
Kupffer cells (KCs) are highly abundant, intravascular, liver-resident macrophages known for their scavenger and phagocytic functions. KCs can also present antigens to CD8+ T cells and promote either tolerance or effector differentiation, but the mechanisms underlying these discrepant outcomes are poorly understood. Here, we used a mouse model of hepatitis B virus (HBV) infection, in which HBV-specific naive CD8+ T cells recognizing hepatocellular antigens are driven into a state of immune dysfunction, to identify a subset of KCs (referred to as KC2) that cross-presents hepatocellular antigens upon interleukin-2 (IL-2) administration, thus improving the antiviral function of T cells. Removing MHC-I from all KCs, including KC2, or selectively depleting KC2 impaired the capacity of IL-2 to revert the T cell dysfunction induced by intrahepatic priming. In summary, by sensing IL-2 and cross-presenting hepatocellular antigens, KC2 overcome the tolerogenic potential of the hepatic microenvironment, suggesting new strategies for boosting hepatic T cell immunity.
Assuntos
Apresentação de Antígeno/imunologia , Linfócitos T CD8-Positivos/imunologia , Apresentação Cruzada/imunologia , Interleucina-2/imunologia , Células de Kupffer/imunologia , Animais , Hepatite B/imunologia , Tolerância Imunológica/imunologia , Camundongos , Camundongos TransgênicosRESUMO
Considering that the heterogenic population of a hepatic progenitor cell line (HPCL) can play a vital role in autoimmune hepatitis (AIH), we decided to conduct pioneering retrospective evaluation of these cells in pediatric AIH by means of transmission electron microscopy (TEM). The aim of the study was to assess the ultrastructure of the HPCL in children with untreated AIH. Ultrastructural analysis of the HPCL population, preceded by immunohistochemical staining for cytokeratin 7 (CK7), was performed using pretreatment liver biopsies from 23 children with clinicopathologically diagnosed AIH. Immunohistochemical assessment for CK7 allowed detection of proliferating immature epithelial cells differentiating towards periportal and intralobular intermediate hepatocytes without marked formation of ductular reactions in AIH children. Using TEM, we distinguished three morphological types of HPCs: I-the most undifferentiated progenitor cells; III-intermediate hepatocyte-like cells; II-intermediate bile duct cells. Most frequent were the cells differentiating towards hepatocytes, most rare-those differentiating towards cholangiocytes. The results indicate that an HPCL may be an important source of hepatocyte regeneration. Ultrastructural analyses of the HPCL population, combined with immunohistochemistry for CK7, might be a useful tool to evaluate liver cell regeneration, including fibrogenesis, and may help better understand the morphological pattern of the disease, in pediatric AIH. Frequent appearance of an HPCL in the vicinity of fibrotic foci, often accompanied by hyperactive Kupffer cells and transitional hepatic stellate cells, may indicate their significant involvement in liver fibrogenesis.
Assuntos
Hepatite Autoimune/metabolismo , Imuno-Histoquímica , Queratina-7/metabolismo , Regeneração Hepática , Fígado/metabolismo , Microscopia Eletrônica de Transmissão , Células-Tronco/metabolismo , Adolescente , Fatores Etários , Biomarcadores/sangue , Diferenciação Celular , Linhagem Celular , Proliferação de Células , Criança , Pré-Escolar , Feminino , Hepatite Autoimune/imunologia , Hepatite Autoimune/patologia , Hepatócitos/imunologia , Hepatócitos/metabolismo , Hepatócitos/ultraestrutura , Humanos , Células de Kupffer/imunologia , Células de Kupffer/metabolismo , Células de Kupffer/ultraestrutura , Fígado/imunologia , Fígado/ultraestrutura , Masculino , Valor Preditivo dos Testes , Estudos Retrospectivos , Células-Tronco/imunologia , Células-Tronco/ultraestruturaRESUMO
Non-alcoholic fatty liver disease (NAFLD) is a leading cause of liver cirrhosis and hepatocellular carcinoma. NAFLD is associated with metabolic disorders such as obesity, insulin resistance, dyslipidemia, steatohepatitis, and liver fibrosis. Liver-resident (Kupffer cells) and recruited macrophages contribute to low-grade chronic inflammation in various tissues by modulating macrophage polarization, which is implicated in the pathogenesis of metabolic diseases. Abnormalities in the intestinal environment, such as the gut microbiota, metabolites, and immune system, are also involved in the pathogenesis and development of NAFLD. Hepatic macrophage activation is induced by the permeation of antigens, endotoxins, and other proinflammatory substances into the bloodstream as a result of increased intestinal permeability. Therefore, it is important to understand the role of the gut-liver axis in influencing macrophage activity, which is central to the pathogenesis of NAFLD and nonalcoholic steatohepatitis (NASH). Not only probiotics but also biogenics (heat-killed lactic acid bacteria) are effective in ameliorating the progression of NASH. Here we review the effect of hepatic macrophages/Kupffer cells, other immune cells, intestinal permeability, and immunity on NAFLD and NASH and the impact of probiotics, prebiotics, and biogenesis on those diseases.
Assuntos
Microbioma Gastrointestinal/imunologia , Hepatopatia Gordurosa não Alcoólica , Prebióticos , Probióticos , Animais , Carcinoma Hepatocelular/imunologia , Carcinoma Hepatocelular/microbiologia , Humanos , Células de Kupffer/imunologia , Neoplasias Hepáticas/imunologia , Neoplasias Hepáticas/microbiologia , Hepatopatia Gordurosa não Alcoólica/imunologia , Hepatopatia Gordurosa não Alcoólica/microbiologiaRESUMO
The biogenesis of high-density lipoprotein (HDL) requires apoA1 and the cholesterol transporter ABCA1. Although the liver generates most of the HDL in the blood, HDL synthesis also occurs in the small intestine. Here, we show that intestine-derived HDL traverses the portal vein in the HDL3 subspecies form, in complex with lipopolysaccharide (LPS)-binding protein (LBP). HDL3, but not HDL2 or low-density lipoprotein, prevented LPS binding to and inflammatory activation of liver macrophages and instead supported extracellular inactivation of LPS. In mouse models involving surgical, dietary, or alcoholic intestinal insult, loss of intestine-derived HDL worsened liver injury, whereas outcomes were improved by therapeutics that elevated and depended upon raising intestinal HDL. Thus, protection of the liver from injury in response to gut-derived LPS is a major function of intestinally synthesized HDL.
Assuntos
Intestino Delgado/metabolismo , Lipoproteínas HDL3/metabolismo , Hepatopatias/prevenção & controle , Fígado/metabolismo , Veia Porta/metabolismo , Proteínas de Fase Aguda/metabolismo , Adulto , Animais , Proteínas de Transporte/metabolismo , HDL-Colesterol/sangue , HDL-Colesterol/metabolismo , Enterócitos/metabolismo , Humanos , Intestino Delgado/cirurgia , Células de Kupffer/imunologia , Células de Kupffer/metabolismo , Receptores de Lipopolissacarídeos/metabolismo , Lipopolissacarídeos/metabolismo , Lipoproteínas HDL3/sangue , Fígado/patologia , Cirrose Hepática/patologia , Cirrose Hepática/prevenção & controle , Hepatopatias/patologia , Receptores X do Fígado/metabolismo , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Ligação Proteica , Transdução de Sinais , Receptor 4 Toll-Like/metabolismoRESUMO
In the murine liver, there are two major macrophage populations, namely resident Kupffer cells (resKCs) with phagocytic activity and recruited macrophages (recMφs) with cytokine-producing capacity. This study was performed to clarify the functional differences between these two populations, focusing on their susceptibility to radiation and response to stimulation via liver X receptors (LXRs), which are implicated in cholesterol metabolism and immune regulation. Liver mononuclear cells (MNCs) were obtained from C57BL/6 (WT) mice with or without 2 Gy irradiation, and the phagocytic activity against Escherichia coli (E. coli) as well as TNF-α production were compared between the two macrophage populations. To assess LXR functions, phagocytosis, TNF-α production, and endocytosis of acetylated low-density lipoprotein (LDL) were compared after synthetic LXR ligand stimulation. Furthermore, LXRα/ß knockout (KO) mice and LXRα KO mice were compared with WT mice. Irradiation decreased intracellular TNF-α production by recMφs but did not affect the phagocytic activity of resKCs. In vitro LXR stimulation enhanced E. coli phagocytosis by resKCs but decreased E. coli-stimulated TNF-α production by recMφs. Phagocytic activity and acetylated LDL endocytosis were decreased in both LXRα/ß KO mice and LXRα KO mice, with serum TNF-α levels after E. coli injection in the former being higher than those in WT mice. In conclusion, resKCs and recMφs exhibited different functional features in response to radiation and LXR stimulation, highlighting their distinct roles liver immunity and lipid metabolism.