Role of TREM2 receptor during the progression of liver disease; from acute liver injury, to chronic liver disease and the development of hepatocellular carcinoma (HCC).

181 p.La lesión e inflamación hepática y el desarrollo del carcinoma hepatocelular (HCC) se modulan en parte a través de la señalización de los receptores de tipo Toll (TLR). El receptor TREM2 (triggering receptor expressed on myeloid cells 2) modula la señalización derivada de TLR4 en macrófagos derivados de la médula ósea. Sin embargo, su papel en el hígado es desconocido. En este estudio, se investigó el papel del receptor TREM2 en la lesión hepática, en la regeneración hepática y en la hepatocarcinogénesis. Para ello, la expresión de TREM2 se analizó en tejido hepático humano cirrótico y en HCC en comparación con tejido hepático control. Además, se realizaron modelos experimentales de daño hepático aguda y crónico, de regeneración hepática y de HCC en ratones salvajes y Trem2-/-. Así, pudimos observar que la expresión de TREM2 se encontraba inducida tanto en tejido cirrótico como en HCC comparado con tejido hepático control y que TREM2 se expresaba en células hepáticas no parenquimales y se inducía tras la lesión hepática, la regeneración hepática y en el HCC en ratones. Además, Los ratones Trem2-/- desarrollan un mayor daño hepático, inflamación, peroxidación lipídica y reclutamiento de macrófagos tras la intoxicación con CCl4 o paracetamol. Por otro lado, los hígados Trem2-/- regeneran más rápido, ya que muestran una aumento de la proliferación hepatocitaria asociada a un incremento en la inflamación en estadios tempranos tras hepatectomía parcial. Finalmente, los ratones Trem2-/- desarrollan más tumores hepáticos tras la administración del hepatocarcinógeno dietilnitrosamina, asociado a un aumento en el daño hepático, inflamación, niveles de estrés oxidativo y proliferación hepatocitaria. En conclusión, TREM2 se presenta como una nueva diana terapéutica en el tratamiento de diversas enfermedades hepáticas, ya que actúa como un freno natural en la inflamación tras la lesión hepatocelular, siendo un regulador crítico en diversos tipos de lesión hepatotóxica y hepatocarcinogénica.BioDonostia: osasun ikerketa institutua, Instituto de investigación sanitaria EASL: the Home of Hepatolog

Role of TREM2 receptor during the progression of liver disease; from acute liver injury, to chronic liver disease and the development of hepatocellular carcinoma (HCC).

181 p.La lesión e inflamación hepática y el desarrollo del carcinoma hepatocelular (HCC) se modulan en parte a través de la señalización de los receptores de tipo Toll (TLR). El receptor TREM2 (triggering receptor expressed on myeloid cells 2) modula la señalización derivada de TLR4 en macrófagos derivados de la médula ósea. Sin embargo, su papel en el hígado es desconocido. En este estudio, se investigó el papel del receptor TREM2 en la lesión hepática, en la regeneración hepática y en la hepatocarcinogénesis. Para ello, la expresión de TREM2 se analizó en tejido hepático humano cirrótico y en HCC en comparación con tejido hepático control. Además, se realizaron modelos experimentales de daño hepático aguda y crónico, de regeneración hepática y de HCC en ratones salvajes y Trem2-/-. Así, pudimos observar que la expresión de TREM2 se encontraba inducida tanto en tejido cirrótico como en HCC comparado con tejido hepático control y que TREM2 se expresaba en células hepáticas no parenquimales y se inducía tras la lesión hepática, la regeneración hepática y en el HCC en ratones. Además, Los ratones Trem2-/- desarrollan un mayor daño hepático, inflamación, peroxidación lipídica y reclutamiento de macrófagos tras la intoxicación con CCl4 o paracetamol. Por otro lado, los hígados Trem2-/- regeneran más rápido, ya que muestran una aumento de la proliferación hepatocitaria asociada a un incremento en la inflamación en estadios tempranos tras hepatectomía parcial. Finalmente, los ratones Trem2-/- desarrollan más tumores hepáticos tras la administración del hepatocarcinógeno dietilnitrosamina, asociado a un aumento en el daño hepático, inflamación, niveles de estrés oxidativo y proliferación hepatocitaria. En conclusión, TREM2 se presenta como una nueva diana terapéutica en el tratamiento de diversas enfermedades hepáticas, ya que actúa como un freno natural en la inflamación tras la lesión hepatocelular, siendo un regulador crítico en diversos tipos de lesión hepatotóxica y hepatocarcinogénica.BioDonostia: osasun ikerketa institutua, Instituto de investigación sanitaria EASL: the Home of Hepatolog

TREM-2 plays a protective role in cholestasis by acting as a negative regulator of inflammation

Background & Aims: Inflammation, particularly that mediated by bacterial components translocating from the gut to the liver and binding to toll-like receptors (TLRs), is central to cholestatic liver injury. The triggering receptor expressed on myeloid cells-2 (TREM-2) inhibits TLR-mediated signaling and exerts a protective role in hepatocellular injury and carcinogenesis. This study aims to evaluate the role of TREM-2 in cholestasis.Methods: TREM-2 expression was analyzed in the livers of pa-tients with primary biliary cholangitis (PBC) or primary scle-rosing cholangitis (PSC), and in mouse models of cholestasis. Wild-type (WT) and Trem-2 deficient (Trem-2-/-) mice were subjected to experimental cholestasis and gut sterilization. Pri-mary cultured Kupffer cells were incubated with lipopolysac-charide and/or ursodeoxycholic acid (UDCA) and inflammatory responses were analyzed.Results: TREM-2 expression was upregulated in the livers of patients with PBC or PSC, and in murine models of cholestasis. Compared to WT, the response to bile duct ligation (BDL)-induced obstructive cholestasis or alpha-naphtylisothiocyanate (ANIT)-induced cholestasis was exacerbated in Trem-2-/-mice. This was characterized by enhanced necroptotic cell death, in-flammatory responses and biliary expansion. Antibiotic treat-ment partially abrogated the effects observed in Trem-2-/-mice after BDL. Experimental overexpression of TREM-2 in the liver of WT mice downregulated ANIT-induced IL-33 expression and neutrophil recruitment. UDCA regulated Trem-1 and Trem-2 expression in primary cultured mouse Kupffer cells and damp-ened inflammatory gene transcription via a TREM-2-dependent mechanism.Conclusions: TREM-2 acts as a negative regulator of inflamma-tion during cholestasis, representing a novel potential thera-peutic target.Lay summary: Cholestasis (the reduction or cessation of bile flow) causes liver injury. This injury is exacerbated when gut-derived bacterial components interact with receptors (spe-cifically Toll-like receptors or TLRs) on liver-resident immune cells, promoting inflammation. Herein, we show that the anti-inflammatory receptor TREM-2 dampens TLR-mediated signaling and hence protects against cholestasis-induced liver injury. Thus, TREM-2 could be a potential therapeutic target in cholestasis.Spanish Carlos III Health Institute (ISCIII) [J.M. Banales (FIS PI18/01075, PI21/00922 and Miguel Servet Program CPII19/00008); M.J. Perugorria (FIS PI14/00399, PI17/00022 and PI20/00186); J.J.G. Marin (FIS PI16/00598 and PI19/00819); P.M. Rodrigues (Sara Borrell CD19/00254)] cofinanced by “Fondo Europeo de Desarrollo Regional” (FEDER); “Instituto de Salud Carlos III” [CIBERehd: M.J. Monte, J.J.G. Marin, J.M. Banales, M.J. Perugorria, P. Aspichueta, P.M. Rodrigues and L. Bujanda], Spain; “Diputación Foral de Gipuzkoa” (M.J. Perugorria: DFG18/114), Department of Health of the Basque Country (M.J. Perugorria: 2019111024, 2015111100 and J.M. Banales: 2021111021), “Euskadi RIS3” (J.M. Banales: 2019222054, 2020333010, 2021333003), and Department of Industry of the Basque Country (J.M. Banales: Elkartek: KK-2020/00008); “Junta de Castilla y Leon” (J.J.G. Marin: SA063P17). La Caixa Scientific Foundation (J.M. Banales: HR17-00601). “Fundación Científica de la Asociación Española Contra el Cáncer” (AECC Scientific Foundation, to J.M. Banales and J.J.G. Marin); “Centro Internacional sobre el Envejecimiento” (J.J.G. Marin: OLD-HEPAMARKER, 0348_CIE_6_E); Fundació Marato TV3 (J.J.G. Marin: Ref. 201916-31). O Sharif was funded by the Austrian Science Fund (FWF-P35168). Work in the lab of T. Luedde was funded by the European Research Council (ERC) (Grant Agreement 771083), the German Research Foundation (DFG – LU 1360/3-2 (279874820), LU 1360/4-(1461704932) and SFB-CRC 1382-Project A01) and the German Ministry of Health (BMG – DEEP LIVER 2520DAT111). Contributions of M. Marzioni were funded by the Università Politecnica delle Marche PSA2017_UNIVPM grant. Contributions of DAM were supported by programme grants from CRUK (C18342/A23390) and MRC (MR/K0019494/1 and MR/R023026/1). MJ Perugorria was funded by the Spanish Ministry of Economy and Competitiveness (MINECO: “Ramón y Cajal” Programme RYC-2015-17755), I. Labiano, A. Agirre-Lizaso, P. Olaizola, A. Echebarria and F. González-Romero by the Basque Government (PRE_2016_1_0152, PRE_2018_1_0184, PRE_2016_1_0269 PRE_2020_1_0080, PRE_2018_1_0120, respectively), I. Olaizola by the Ministry of Universities (FPU 19/03327) and A. Esparza-Baquer by the University of the Basque Country (PIF2014/11). The funding sources had no involvement in study design, data collection and analysis, decision to publish, or preparation of the article

TREM-2 defends the liver against hepatocellular carcinoma through multifactorial protective mechanisms

[EN] Objective Hepatocellular carcinoma (HCC) is a prevalent and aggressive cancer usually arising on a background of chronic liver injury involving inflammatory and hepatic regenerative processes. The triggering receptor expressed on myeloid cells 2 (TREM-2) is predominantly expressed in hepatic non-parenchymal cells and inhibits Toll-like receptor signalling, protecting the liver from various hepatotoxic injuries, yet its role in liver cancer is poorly defined. Here, we investigated the impact of TREM-2 on liver regeneration and hepatocarcinogenesis. Design TREM-2 expression was analysed in liver tissues of two independent cohorts of patients with HCC and compared with control liver samples. Experimental HCC and liver regeneration models in wild type and Trem-2-/- mice, and in vitro studies with hepatic stellate cells (HSCs) and HCC spheroids were conducted. Results TREM-2 expression was upregulated in human HCC tissue, in mouse models of liver regeneration and HCC. Trem-2-/- mice developed more liver tumours irrespective of size after diethylnitrosamine (DEN) administration, displayed exacerbated liver damage, inflammation, oxidative stress and hepatocyte proliferation. Administering an antioxidant diet blocked DEN-induced hepatocarcinogenesis in both genotypes. Similarly, Trem-2-/- animals developed more and larger tumours in fibrosis-associated HCC models. Trem-2-/- livers showed increased hepatocyte proliferation and inflammation after partial hepatectomy. Conditioned media from human HSCs overexpressing TREM-2 inhibited human HCC spheroid growth in vitro through attenuated Wnt ligand secretion. Conclusion TREM-2 plays a protective role in hepatocarcinogenesis via different pleiotropic effects, suggesting that TREM-2 agonism should be investigated as it might beneficially impact HCC pathogenesis in a multifactorial manner.Spanish Ministry of Economy and Competitiveness and ’Instituto de Salud Carlos III’ grants (MJP (PI14/00399, PI17/00022 and Ramon y Cajal Programme RYC-2015–17755); JMB (PI12/00380, PI15/01132, PI18/01075, Miguel Servet Programme CON14/00129 and CPII19/00008) cofinanced by ’Fondo Europeo de Desarrollo Regional’ (FEDER); CIBERehd: MJP, JMB and LB), Spain; IKERBASQUE, Basque foundation for Science (MJP and JMB), Spain; ’Diputación Foral de Gipuzkoa’ (MJP: DFG18/114, DFG19/081; JMB: DFG15/010, DFG16/004); BIOEF (Basque Foundation for Innovation and Health Research: EiTB Maratoia BIO15/CA/016/ BD to JMB); Department of Health of the Basque Country (MJP: 2015111100 and 2019111024; JMB: 2017111010), Euskadi RIS3 (JMB: 2016222001, 2017222014, 2018222029, 2019222054, 2020333010) Department of Industry of the Basque Country (JMB: Elkartek: KK-2020/00008) and AECC Scientific Foundation (JMB). AE-B was funded by the University of the Basque Country (UPV/EHU) (PIF2014/11) and by the short-term training fellowship Andrew K Burroughs (European Association for the Study of the Liver, EASL). IL and AA-L were funded by the Department of Education, Language Policy and Culture of the Basque Government (PRE_2016_1_0152 and PRE_2018_1_0184). OS and SK were funded by the Austrian Science Fund (FWF25801-B22, FWF-P35168 to OS and L-Mac: F 6104-B21 to SK). FO and DAM were funded by a UK Medical Research Council programme Grant MR/R023026/1. DAM was also funded by the CRUK programme grant C18342/A23390, CRUK/AECC/AIRC Accelerator Award A26813 and the MRC MICA programme grant MR/R023026/1. JBA is supported by the Danish Medical Research Council, Danish Cancer Society, Nordisk Foundation, and APM Foundation. CJO’R and PM-G are supported by Marie Sklodowska-Curie Programme and EASL Sheila Sherlock postdoctoral fellowships

Gene expression profiling reveals new pathways and genes associated with visna/maedi viral disease

Visna/Maedi virus (VMV) is a lentivirus that infects the cells of the monocyte/macrophage lineage in sheep, goats and wild ruminants. Infection with VMV causes a multisystemic inflammatory disorder, which includes pneumonia, encephalitis, mastitis or arthritis. The immune response to VMV infection is complex, and the infection and pathogenesis of this virus are not totally characterized yet. In this work, a gene expression microarray was used to identify the differentially ex-pressed genes in VMV infection and disease development by comparing sheep with different serologic status and with presence of VM-characteristic clinical lesions. The expression profile analysis has revealed many interesting genes that may be associated with the viral infection process. Among them, the OXT gene appeared significantly up-regulated, so the oxytocin-secreting system could play an essential role in VM disease. Moreover, some of the most significantly enriched functions in up-regulated genes appeared the complement pathway, which (in combination with the Toll-like receptor signaling network) could compose a mechanism in the VMV pathogenesis. Identifying the host genetic factors associated with VMV infection can be applied to develop strategies for preventing infection and develop effective vaccines that lead to therapeutic treatments.Financial support for this work was provided by the UPV/EHU (grants GIU14/23, UFI11/20 and PPGA18/11 to BMJugo) and a postdoctoral grant to Naiara Abendaño (ESP-DOC16/43)

Non-parenchymal TREM-2 protects the liver from immune-mediated hepatocellular damage

Objective: Liver injury impacts hepatic inflammation in part via Toll-like receptor (TLR) signalling. Triggering receptor expressed on myeloid cells 2 (TREM-2) modulates TLR4-mediated inflammation in bone marrow (BM)-derived macrophages but its function in liver injury is unknown. Here we hypothesised that the anti-inflammatory effects of TREM-2 on TLR signalling may limit hepatic injury. Design: TREM-2 expression was analysed in livers of humans with various forms of liver injury compared with control individuals. Acute and chronic liver injury models were performed in wild type and Trem-2-/- mice. Primary liver cells from both genotypes of mice were isolated for in vitro experiments. Results: TREM-2 was expressed on non-parenchymal hepatic cells and induced during liver injury in mice and man. Mice lacking TREM-2 exhibited heightened liver damage and inflammation during acute and repetitive carbon tetrachloride and acetaminophen (APAP) intoxication, the latter of which TREM-2 deficiency was remarkably associated with worsened survival. Liver damage in Trem-2-/- mice following chronic injury and APAP challenge was associated with elevated hepatic lipid peroxidation and macrophage content. BM transplantation experiments and cellular reactive oxygen species assays revealed effects of TREM-2 in the context of chronic injury depended on both immune and resident TREM-2 expression. Consistent with effects of TREM-2 on inflammation-associated injury, primary hepatic macrophages and hepatic stellate cells lacking TREM-2 exhibited augmented TLR4-driven proinflammatory responses. Conclusion: Our data indicate that by acting as a natural brake on inflammation during hepatocellular injury, TREM-2 is a critical regulator of diverse types of hepatotoxic injury