Mouse Model Of Biliary Atresia Research Articles

Polymeric immunoglobulin receptor promotes Th2 immune response in the liver by increasing cholangiocytes derived IL-33: a diagnostic and therapeutic biomarker of biliary atresia

Biliary atresia (BA) is a devastating neonatal cholangiopathy with an unclear pathogenesis, and prompt diagnosis of BA is currently challenging. Proteomic and immunoassay analyses were performed with serum samples from 250 patients to find potential BA biomarkers. The expression features of polymeric immunoglobulin receptor (PIGR) were investigated using human biopsy samples, three different experimental mouse models, and cultured human biliary epithelial cells (BECs). Chemically modified small interfering RNA and adenovirus expression vector were applied for invivo silencing and overexpressing PIGR in a rotavirus-induced BA mouse model. Luminex-based multiplex cytokine assays and RNA sequencing were used to explore the molecular mechanism of PIGR involvement in the BA pathogenesis. Serum levels of PIGR, poliovirus receptor (PVR), and aldolase B (ALDOB) were increased in BA patients and accurately distinguished BA from infantile hepatitis syndrome (IHS). Combined PIGR and PVR analysis distinguished BA from IHS with an area under the receiver operating characteristic curve of 0.968 and an accuracy of 0.935. PIGR expression was upregulated in the biliary epithelium of BA patients; Th1 cytokines TNF-α and IFN-γ induced PIGR expression in BECs via activating NF-κB pathway. Silencing PIGR alleviated symptoms, reduced IL-33 expression, and restrained hepatic Th2 inflammation in BA mouse model; while overexpressing PIGR increased liver fibrosis and IL-33 expression, and boosted hepatic Th2 inflammation in BA mouse model. PIGR expression promotes the proliferation and epithelial-mesenchymal transition, and reduced the apoptosis of BECs. PIGR participated in BA pathogenesis by promoting hepatic Th2 inflammation via increasing cholangiocytes derived IL-33; PIGR has the value as a diagnostic and therapeutic biomarker of BA. This study was financially supported by the National Natural Science Foundation of China (82170529), the National Key R&D Program (2021YFC2701003), and the National Natural Science Foundation of China (82272022).

Long non-coding RNA growth arrest-specific 5 inhibits liver fibrogenesis in biliary atresia by interacting with microRNA-222 and repressing IGF1/AKT signaling.

Long non-coding RNA growth arrest-specific 5 (lncRNA GAS5) has been shown to inhibit liver fibrosis through serving as a competing endogenous RNA for microRNA-222 (miR-222). Progressive liver fibrosis is a typical characteristic of biliary atresia (BA). However, the role of GAS5/miR-222 and its underlying mechanisms remain largely unknown in BA. The expression of GAS5 was determined in the liver and primary hepatic stellate cells (HSCs) of BA patients. Then, the effects of GAS5 on the activation and proliferation of HSCs were evaluated. Furthermore, the interaction between GAS5 and miR-222 was investigated by a luciferase gene report assay. Next, the effects of IGF1/AKT signaling were determined to clarify the downstream mechanism of GAS5. Finally, GAS5 administration was performed to explore its role in an experimental BA mouse model. GAS5 expression was decreased in liver tissues and HSCs of BA patients, and was inversely correlated with liver fibrosis in BA. Up-regulation of GAS5 in LX-2 cells significantly reduced smooth muscle α-actin (α-SMA) and collagen 1a1 (COL1A1) expression, inhibited cell proliferation and clone formation ability, induced S phase increase, and promoted cell apoptosis. Moreover, GAS5 was negatively regulated by miR-222, which promoted HSCs activation and proliferation, and was positively correlated with liver fibrosis in BA. Additionally, the expressions of IGF1, p-PI3K, and p-AKT were decreased when LX-2 cells over-expressed GAS5, whereas knockdown of IGF1 or AKT significantly decreased α-SMA and COL1A1 expression, suppressed cell proliferation, and enhanced cell apoptosis in LX-2 cells. Furthermore, GAS5 administration significantly increased apoptosis and reduced liver fibrosis, α-SMA and COL1A1 expressions in liver tissues of BA mice. GAS5 inhibited liver fibrosis in BA by interacting with miR-222 and regulating IGF1/AKT signaling, which may be a therapeutic target to alleviate liver fibrosis in BA.

The association of immune-related genes and the potential role of IL10 with biliary atresia.

Biliary atresia (BA) is a severe immune-related disease that is characterized by biliary obstruction and cholestasis. The etiology of BA is unclear, our aim was to explore the relationship between biliary tract inflammation and immune-related genes. We selected 14 SNPs in 13 immune-related genes and investigated their associations with BA by using a large case‒control cohort with a total of 503 cases and 1473 controls from southern China. SNP rs1518111 in interleukin10 (IL10) was identified as associated with BA (P = 5.79E-03; OR: 0.80; 95% CI: 0.68-0.94). The epistatic effects of the following pairwise interactions among these SNPs were associated with BA: signal transducer and activator of transcription 4 (STAT4) and chemokine (C-X-C motif) ligand 3 (CXCL3); STAT4 and damage-regulated autophagy modulator1 (DRAM1); CXCL3 and RAD51 paralog B (RAD51B); and interferon gamma (IFNG) and interleukin26 (IL26). Furthermore, we explored the potential role of IL-10 in the pathogenesis of the neonatal mouse model of BA. IL-10 effectively prevented biliary epithelial cell injury and biliary obstruction in murine BA as well as inhibit the activation of BA-related immune cells. In conclusion, this study provided strong evidence implicating IL10 as a susceptibility gene for BA in the southern Chinese population. This study provided strong evidence implicating IL10 as a susceptibility gene for BA in the southern Chinese population. This study could infer that IL-10 may play a protective role in BA mouse model. We found that four SNPs (rs7574865, rs352038, rs4622329, and rs4902562) have genetic interactions.

A Mouse Model of Chronic Liver Fibrosis for the Study of Biliary Atresia.

Biliary atresia (BA) is a fatal disease involving obstructive jaundice, and it is the most common indication for liver transplantation in children. Due to the complex etiology and unknown pathogenesis, there are still no effective drug treatments. At present, the classic BA mouse model induced by rhesus rotavirus (RRV) is the most commonly used model for studying the pathogenesis of BA. This model is characterized by growth retardation, jaundice of the skin and mucosa, clay stools, and dark yellow urine. The histopathology shows severe liver inflammation and obstruction of the intrahepatic and extrahepatic bile ducts, which are similar to the symptoms of human BA. However, the livers of end-stage mice in this model lack fibrosis and cannot fully simulate the characteristics of liver fibrosis in clinical BA. The presented study developed a novel BA mouse model of chronic liver fibrosis by injecting 5-10 µg of anti-Ly6G antibody four times, with gaps of 2 days after each injection. The results showed that some of the mice successfully formed chronic BA with typical fibrosis after the time lapse, meaning these mice represent a suitable animal model for the virus-induced liver fibrosis mechanistic study of BA and a platform for developing future BA treatments.

TWEAK/FN14 promotes profibrogenic pathway activation in Prominin-1-expressing hepatic progenitor cells in biliary atresia.

Biliary atresia (BA), a congenital cholestatic liver disease, commonly culminates in end-stage liver disease. We previously demonstrated in BA that Prominin-1 ( Prom1 )-expressing hepatic progenitor cells (HPCs) expand within regions of developing fibrosis, giving rise to cholangiocytes within biliary ductular reactions. Null mutation of Prom1 or ablation of cells expressing Prom1 significantly diminishes fibrogenesis. FN14, the receptor for TNF-like weak inducer of apoptosis (TWEAK), is expressed by HPCs. TWEAK/FN14 signaling promotes fibrosis in multiple organ systems. Therefore, we hypothesized that TWEAK/FN14 signaling mediates Prom1 -expressing HPC proliferation leading to profibrogenic ductular reactions in BA. The experimental mouse model of BA mediated by perinatal rhesus rotavirus (RRV) infection resulted in increased co-expression of Fn14 in Prom1 -expressing HPCs within regions of ductular reactions. FN14 antagonist L524-0366 decreased ductular reactions, biliary fibrosis and periportal fibroblast activation in RRV injury. L524-0366 inhibition also demonstrated loss of downstream noncanonical NF-kB signaling expression in RRV injury. Murine HPC organoids demonstrated accelerated organoid growth and proliferation when treated with recombinant TWEAK. Increased organoid proliferation with recombinant TWEAK was lost when also treated with L524-0366. Analysis of a large publicly available RNA sequencing database of BA and normal control patients revealed significant increases in expression of PROM1 , FN14 , and genes downstream of TNF signaling and noncanonical NF-κB signaling pathways in BA infants. Infants who failed to achieve bile drainage after hepatoportoenterostomy had higher relative levels of FN14 expression. TWEAK/FN14 signaling activation in Prom1 -expressing HPCs contributes to proliferation of profibrogenic ductular reactions in BA.

Human poliovirus receptor contributes to biliary atresia pathogenesis by exacerbating natural-killer-cell-mediated bile duct injury.

Natural killer (NK) cells play an important role in biliary atresia (BA) pathogenesis; human poliovirus receptor (PVR) is an important NK-cell modulator. Here, we explored the role of PVR in BA pathogenesis. Poliovirus receptor expression and NK cell-associated genes were detected in human BA samples and a rotavirus-induced BA mouse model using quantitative PCR and immunofluorescence staining. Chemically modified small interfering RNA silenced PVR expression in the BA model, and its effects on the population and function of intrahepatic NK cells were investigated using flow cytometry (FCM). The effects of PVR overexpression and knockdown on proliferation, apoptosis and NK-cell-mediated lysis of cultured human cholangiocytes were analysed using FCM and cell viability assays. Serum PVR, high-mobility group box 1 (HMGB1), and interleukin-1beta (IL-1beta) levels were measured in a cohort of 50 patients using ELISA. Poliovirus receptor expression was upregulated in the biliary epithelium of BA patients and BA model and was positively correlated with the population and activation of intrahepatic NK cells. Silencing of PVR expression impaired the cytotoxicity of NK cells, reduced inflammation and protected mice from rotavirus-induced BA. Activation of the TLR3-IRF3 signalling pathway induced PVR expression in cultured cholangiocytes. PVR overexpression promoted proliferation and inhibited the apoptosis of cholangiocytes but exacerbated NK cell-mediated cholangiocyte lysis. Serum PVR levels were elevated in BA patients and were positively correlated with HMGB1 and IL-1beta levels. Poliovirus receptor contributes to BA pathogenesis by regulating NK cell-mediated bile duct injury; PVR has the value as a biomarker of BA.

Regulatory T Cell (Treg) Cytotoxic T Lymphocyte-associated Antigen-4 Deficits in Biliary Atresia (BA) and Disease Rescue With Treg Augmentation in Murine BA.

Biliary atresia (BA) entails an inflammatory injury of the biliary tree, leading to fibrosis of the extrahepatic and intrahepatic bile ducts. The chronic inflammatory biliary injury may be due to lack of appropriate regulatory T cell (Treg) suppression of inflammation. The aims of the study were to characterize Treg deficits in human BA and to determine if Treg augmentation therapy improved outcomes in the rhesus rotavirus (RRV)-induced mouse model of BA. Immunophenotyping of human peripheral blood and liver Tregs was performed with flow cytometry, Vectra-6 multicolor immunohistochemistry (IHC), and real-time polymerase chain reaction. Measured outcomes of Treg augmentation with the interleukin-2 monoclonal antibody JES6-1/interleukin-2 in the RRV-induced mouse model of BA included survival, direct bilirubin, IHC, and liver flow cytometry. Patients with BA had decreased peripheral blood Treg frequency and lack of cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) upregulation despite a highly activated, effector Treg phenotype. IHC revealed decreased liver Treg frequency and Treg CTLA-4 expression. Treg augmentation in the murine model led to increased survival, decreased direct bilirubin levels and liver inflammation, and expansion of resident macrophages. In addition to the M2 phenotype of resident macrophages, these cells adopted an inflammatory M1 phenotype in response to RRV infection, which was inhibited with Treg augmentation. Patients with BA have Treg deficiencies associated with lack of sufficient CTLA-4 expression that is necessary for cell-cell contact inhibition of inflammatory responses. Treg augmentation therapy in murine BA protected from disease. Future treatment trials for BA should include agents that enhance Treg number or function, mimic CTLA-4 function, and promote anti-inflammatory M2 macrophage phenotypes.

Nr4a1 As a Regulator of Monocyte Subsets in a Mouse Model of Biliary Atresia

Nr4a1 As a Regulator of Monocyte Subsets in a Mouse Model of Biliary Atresia

YAP Activation and Implications in Patients and a Mouse Model of Biliary Atresia.

Background and Aim: Biliary atresia (BA), an inflammatory destruction of the bile ducts, leads to liver fibrosis in infants and accounts for half of cases undergoing pediatric liver transplantation. Yes-associated protein (YAP), an effector of the Hippo signaling pathway, is critical in maintaining identities of bile ductal cells. Here, we evaluated the expression of YAP and YAP target genes in BA livers and a rhesus rotavirus (RRV)-induced BA mice model.Methods: Liver specimens collected from 200 BA patients were compared with those of 30 non-BA patients. Model mice liver tissues were also collected. The expression of YAP and YAP target genes were measured by transfection, RNA-seq, immunohistochemistry, immunoblot, and quantitative PCR. Masson's trichrome staining and the Biliary Atresia Research Consortium (BARC) system were utilized to score liver fibrosis status.Results: The expression of YAP is elevated and positively correlated with fibrosis in BA livers. Moreover, ANKRD1, which is identified as the target gene of YAP, is also highly expressed in BA livers. Consistent with clinical data, YAP and ANKRD1 are significantly upregulated in RRV-induced BA mouse model.Conclusions: YAP expression is closely correlated with the bile duct hyperplasia and liver fibrosis, and may serve as an indicator for liver fibrosis and BA progression. This study indicates an involvement of the Hippo signaling pathway in the development of BA, and the YAP induced ANKRD1 expression may also be related to bile duct hyperplasia in BA. This provides a new direction for more in-depth exploration of the etiology and pathogenesis of biliary atresia.

From the Editor's Desk…

From the Editor's Desk…

Synthetic retinoid AM80 inhibits IL‐17 production of gamma delta T cells and ameliorates biliary atresia in mice

AbstractBackground & AimsRecent evidence suggests that Interleukin (IL)‐17‐producing gamma delta () T cells are the dominant pathogenic cellular component in designated autoimmune or inflammatory diseases, including biliary atresia (BA). We have previously demonstrated that retinoids effectively suppress T‐helper cell (Th) 17 differentiation.MethodsHere, we established an in vitro system, enabling investigations of the effect of AM80 on the IL‐17 production of T cells. Additionally, we tested the therapeutic effect of AM80 in the Rotavirus‐induced mouse model of BA. Co‐incubation of T cells with IL‐23 and anti‐CD28 mAb proved most effective in inducing an IL‐17 response in vitro. The effect of AM80 on human CCR6+CD26+ V2 cells was assessed by flow cytometry.ResultsAM80 efficiently reduced IL‐17 production by murine T cells and the expression of the master transcription factor Retinoid‐Orphan‐Receptor‐t (ROR) in a dose‐dependent manner. The fraction of human CCR6+CD26+ V2 cells was significantly reduced by co‐incubation with AM80. Moreover, AM80 also inhibited IL‐17 production by liver‐infiltrating T cells isolated from animals suffering from BA. Intraperitoneal treatment with AM80 ameliorated BA‐associated inflammation. However, AM80 treatment was not sufficient to control disease progression in the murine model, despite reduced inflammatory activity in the animals.ConclusionsRetinoids are very efficient in down‐regulating IL‐17 production by T cells in vitro and, to a lesser extent, in the BA mouse model. However, retinoids do not suffice for the control of disease progression. Thus, our data suggest that IL‐17 is not the only factor contributing to the pathogenesis of BA.Lay summaryBiliary atresia (BA) is a rare disease which affects infants, causing progressive liver failure in most children, and is the most common indication for paediatric liver transplantation. We have previously demonstrated that IL‐17, produced by T cells, contributes to hepatic inflammation in the murine model of BA and is increased in the livers of infants suffering from the disease. In the study at hand, we demonstrate that treatment with AM80, a synthetic retinoid with superior pharmacological properties, effectively inhibits the IL‐17 production of gamma delta T cells without generating systemic immunosuppression. Although all‐trans retinoic acid (ATRA) has been demonstrated to suppress differentiation of IL‐17‐producing conventional T‐helper cells (Th17) in vitro, the therapeutic application of ATRA in vivo is limited by the compound's potential side effects caused by its instability and lack of receptor specificity. Our study is the first to show that AM80 suppresses the IL‐17 production of T cells in a very efficient manner and that hepatic inflammation is ameliorated in mice suffering from BA. However, AM80 treatment does not suffice to block the disease progression. We conclude that factors other than IL‐17 drive the progressive inflammation in BA. The addition of retinoids to the treatment regime of children suffering from BA might decrease the disease burden; however, further research is needed to clarify the pathomechanism and possible therapeutic interventions in humans.

Beta-amyloid deposition around hepatic bile ducts is a novel pathobiological and diagnostic feature of biliary atresia

Biliary atresia (BA) is a poorly understood and devastating obstructive bile duct disease of newborns. It is often diagnosed late, is incurable and frequently requires liver transplantation. In this study, we aimed to investigate the underlying pathogenesis and molecular signatures associated with BA. We combined organoid and transcriptomic analysis to gain new insights into BA pathobiology using patient samples and a mouse model of BA. Liver organoids derived from patients with BA and a rhesus rotavirus A-infected mouse model of BA, exhibited aberrant morphology and disturbed apical-basal organization. Transcriptomic analysis of BA organoids revealed a shift from cholangiocyte to hepatocyte transcriptional signatures and altered beta-amyloid-related gene expression. Beta-amyloid accumulation was observed around the bile ducts in BA livers and exposure to beta-amyloid induced the aberrant morphology in control organoids. The novel observation that beta-amyloid accumulates around bile ducts in the livers of patients with BA has important pathobiological implications, as well as diagnostic potential. Biliary atresia is a poorly understood and devastating obstructive bile duct disease of newborns. It is often diagnosed late, is incurable and frequently requires liver transplantation. Using human and mouse 'liver mini-organs in the dish', weunexpectedly identified beta-amyloid deposition - the main pathological feature of Alzheimer's disease and cerebral amyloid angiopathy - around bile ducts in livers from patients with biliary atresia. This finding reveals a novel pathogenic mechanism that could have important diagnostic and therapeutic implications.

A Silver Nanoparticle Method for Ameliorating Biliary Atresia Syndrome in Mice.

Biliary atresia (BA) is a severe type of cholangitis with high mortality in children of which the etiology is still not fully understood. Viral infections may be one possible cause. The typical animal model used for studying BA is established by inoculating a neonatal mouse with a rhesus rotavirus. Silver nanoparticles have been shown to exert antibacterial and antiviral effects; their function in the BA mouse model is evaluated in this study. Currently, in BA animal experiments, the methods used to improve the symptoms of BA mice are generally symptomatic treatments given via food or other drugs. The aim of this study is to demonstrate a new method for ameliorating BA syndrome in mice by the intraperitoneal injection of silver nanoparticles and to provide detailed methods for preparing the silver nanoparticle gel formulation. This method is simple and widely applicable and can be used to research the mechanism of BA, as well as in clinical treatments. Based on the BA mouse model, when the mice exhibit jaundice, the prepared silver nanoparticle gel is injected intraperitoneally to the surface of the lower liver. The survival status is observed, and biochemical indicators and liver histopathology are examined. This method allows a more intuitive understanding of both the establishment of the BA model and novel BA treatments.

The Role of Neonatal Gr-1+ Myeloid Cells in a Murine Model of Rhesus-Rotavirus–Induced Biliary Atresia

Activation of innate immunity together with cholangiocyte damage occurs in biliary atresia (BA). However, detailed information on the inflammatory cells involved is lacking. This study investigates both the pathophysiology of CD11b+Gr-1+ cells in a mouse model of BA and their presence in BA patients. CD11b+Gr-1+ cells were targeted by an anti-Ly6G antibody in murine BA induced by inoculation with rhesus rotavirus. Expression of the Ly6G homolog CD177+ was examined in biopsies from BA patients. The symptoms of BA were ameliorated, and survival was prolonged in those mice receiving 5 to 10 μg of antibody per mouse every 3 days for four times compared with the mice treated with virus alone. However, the mice later developed chronic BA with persistent low body weight and jaundice. Hepatic inflammatory cells were reduced compared with acute BA. Blockade of extrahepatic bile ducts occurred, whereas intrahepatic ductules were partially preserved, and a progressive increase in liver fibrosis was observed. High levels of CD11b+Gr-1+ cells were present in these mice. The administration of an anti-Ly6G antibody again in those chronic BA mice reduced jaundice and restored body weight. InBA patients CD177+ cells were highly expressed in the liver. Our data suggest that the chronic mouse BA model shares key characteristics with clinical BA and indicates the importance of CD11b+Gr-1+ cells in the initiation and progression of BA.

Antifibrotic potential of bone marrow‑derived mesenchymal stem cells in biliary atresia mice

Biliary atresia (BA) is a rare and severe disease that affects infants where a fibroinflammatory process destroys the bile ducts, leading to fibrosis and biliary cirrhosis, and mortality if untreated. Bone marrow‑derived mesenchymal stem cells (BMMSCs) have been considered as a promising therapy in fibrotic diseases. The aim of the present was to investigate the anti‑fibrotic roles of BMMSC transplantation in a BA mouse model. Mouse BA models were established by Rhesus rotavirus administration to neonatal mice. The results revealed that the liver enzyme and bilirubin metabolism levels, and the levels of the oxidative stress marker malondialdehyde (MDA) and the fibrosis marker were all increased in the BA model, while the liver tissue levels of superoxide dismutase and glutathione peroxidase were reduced. The hematoxylin and eosin and Masson's trichrome staining revealed severe liver fibrosis and collagen accumulation in BA livers. However, these indicators were all reversed once the BA mice were administered the BMMSC inoculation. In conclusion, the present study demonstrated the anti‑fibrotic potential of BMMSCs in BA mice, which may provide a novel approach to ameliorate the fibrotic response in BA patients.

Cytokine-Producing B Cells Promote Immune-Mediated Bile Duct Injury in Murine Biliary Atresia.

Biliary atresia (BA) is a neonatal T cell-mediated, inflammatory, sclerosing cholangiopathy. In the rhesus rotavirus (RRV)-induced neonatal mouse model of BA (murine BA), mice lacking B cells do not develop BA, and the lack of B cells is associated with loss of T-cell and macrophage activation. The aim of this study was to determine the mechanism of B cell-mediated immune activation (antigen presentation versus cytokine production) in murine BA. Normal neonatal B cells in the liver are predominantly at pro-B and pre-B cellular development. However, BA mice exhibit a significant increase in the number and activation status of mature liver B cells. Adoptively transferred B cells into RRV-infected, B cell-deficient mice were able to reinstate T-cell and macrophage infiltration and biliary injury. Nonetheless, neonatal liver B cells were incompetent at antigen presentation to T cells. Moreover, 3-83 immunoglobulin transgenic mice, in which B cells only present an irrelevant antigen, developed BA, indicating a B-cell antigen-independent mechanism. B cells from BA mice produced a variety of innate and adaptive immune cytokines associated with immune activation. In vitro trans-well studies revealed that BA B cells secreted cytokines that activated T cells based on increased expression of T-cell activation marker cluster of differentiation 69. Conclusion: Neonatal liver B cells are highly activated in murine BA and contribute to immune activation through production of numerous cytokines involved in innate and adaptive immunity; this work provides increased knowledge on the capacity of neonatal B cells to contribute to an inflammatory disease through cytokine-mediated mechanisms, and future studies should focus on targeting B cells as a therapeutic intervention in human BA.

Regulation of epithelial injury and bile duct obstruction by NLRP3, IL-1R1 in experimental biliary atresia

Biliary atresia (BA) results from a neonatal inflammatory and fibrosing obstruction of bile ducts of unknown etiology. Although the innate immune system has been linked to the virally induced mechanism of disease, the role of inflammasome-mediated epithelial injury remains largely undefined. Here, we hypothesized that disruption of the inflammasome suppresses the neonatal proinflammatory response and prevents experimental BA. We determined the expression of key inflammasome-related genes in livers from infants at diagnosis of BA and in extrahepatic bile ducts (EHBDs) of neonatal mice after infection with rotavirus (RRV) immediately after birth. Then, we determined the impact of the wholesale inactivation of the genes encoding IL-1R1 (Il1r1-/-), NLRP3 (Nlrp3-/-) or caspase-1 (Casp1-/-) on epithelial injury and bile duct obstruction. IL1R1, NLRP3 and CASP1 mRNA increased significantly in human livers at the time of diagnosis, and in EHBDs of RRV-infected mice. In Il1r1-/- mice, the epithelial injury of EHBDs induced by RRV was suppressed, with dendritic cells unable to activate natural killer cells. A similar protection was observed in Nlrp3-/- mice, with decreased injury and inflammation of livers and EHBDs. Long-term survival was also improved. In contrast, the inactivation of the Casp1 gene had no impact on tissue injury, and all mice died. Tissue analyses in Il1r1-/- and Nlrp3-/- mice showed decreased populations of dendritic cells and natural killer cells and suppressed expression of type-1 cytokines and chemokines. Genes of the inflammasome are overexpressed at diagnosis of BA in humans and in the BA mouse model. In the experimental model, the targeted loss of IL-1R1 or NLRP3, but not of caspase-1, protected neonatal mice against RRV-induced bile duct obstruction. Biliary atresia is a severe inflammatory and obstructive disease of bile ducts occurring in infancy. Although the cause is unknown, activation of the innate and adaptive immune systems injures the bile duct epithelium. In this study we found that patients' livers had increased expression of inflammasome genes. Using mice engineered to inactivate individual inflammasome genes, the epithelial injury and bile duct obstruction were prevented by the loss of Il1r1 or Nlrp3, with a decreased activation of natural killer cells and expression of cytokines and chemokines. In contrast, the loss of Casp1 did not change the disease phenotype. Combined, the findings point to a differential role of inflammasome gene products in the pathogenic mechanisms of biliary atresia.

Inhibition of the Notch Signaling Pathway Reduces the Differentiation of Hepatic Progenitor Cells into Cholangiocytes in Biliary Atresia

Background/Aims: Viral infections, especially with rotavirus, are often considered an initiator of the pathogenesis of biliary atresia (BA). However, the mechanism by which rotavirus induces BA is still unclear. Methods: A BA mouse model was induced in newborn mice by i.p. inoculation with rhesus rotavirus within 6 h of birth. The expression of Notch pathway-associated molecules (JAG1, JAG2, Notch1, Notch2, Notch3, Notch4, DII1, DII3, and DII4) was measured by quantitative PCR and western blot analysis. Bile duct obstruction was detected by hematoxylin and eosin staining and CK-19 immunohistochemical staining. DAPT was used to inhibit the Notch pathway in vivo and in vitro. Results: In the livers of patients with BA and rotavirus-induced BA mice, the expression of JAG1 and Notch2 was significantly increased. Inhibition of the Notch pathway by DAPT in vivo ameliorated bile duct obstruction and delayed BA-induced mortality. The serum levels of inflammation cytokines (TNF-α, IL-2, IL-8, and IL-18) were reduced by inhibiting the Notch pathway. The expression of CK19, Sox9, and EpCAM was significantly increased in BA liver, while DAPT treatment decreased the expression of CK19, Sox9, and EpCAM. Conclusion: Notch activation is involved in the pathogenesis of BA by promoting the differentiation of hepatic progenitor cells into cholangiocytes.

Silver nanoparticle treatment ameliorates biliary atresia syndrome in rhesus rotavirus inoculated mice

Biliary atresia (BA) is a neonatal biliary system disease closely associated with viral infection and bile duct inflammation. Silver nanoparticles (AgNps) have previously revealed antiviral and anti-inflammatory properties. In this study, we have investigated the effects of AgNps in the treatment of the Rhesus rotavirus inoculation induced BA in mice. The morphology, liver histopathology, clinical biochemistry examination, and inflammatory cells were analyzed in BA mice. Results indicated that AgNps could significantly increase the survival rate of BA mice, and reduce jaundice and weight lost and the liver enzymes and bilirubin metabolism clinical parameters were close to the normal levels. Diminished numbers of NK cells were observed by flow cytometry analysis and immunohistochemical staining. Furthermore, the viral load was reduced and transcripts for TGF-β mRNA were augmented after AgNps treatment. Collectively, our results suggest that AgNps treatment has beneficial effects on the BA mouse model partially through upregulation of TGF-β.

Interleukin 17, Produced by γδ T Cells, Contributes to Hepatic Inflammation in a Mouse Model of Biliary Atresia and Is Increased in Livers of Patients

Biliary atresia (BA) is a rare disease ininfants, with unknown mechanisms of pathogenesis. It is characterized by hepatobiliary inflammatory, progressive destruction of the biliary system leading to liver fibrosis, and deterioration of liver function. Interleukin (IL) 17A promotes inflammatory and autoimmune processes. We studied the role of IL17A and cells that produce this cytokine in a mouse model of BA and in hepatic biopsy samples from infants with BA. We obtained peripheral blood and liver tissue specimens from 20 patients with BA, collected at the time of Kasai portoenterostomy, along with liver biopsies from infants without BA (controls). The tissue samples were analyzed by reverse transcription quantitative polymerase chain reaction (PCR), in situ PCR, and flow cytometry analyses. BA was induced in balb/cAnNCrl mice by rhesus rotavirus infection; uninfected mice were used as controls. Liver tissues were collected from mice and analyzed histologically and by reverse transcriptase PCR; leukocytes were isolated, stimulated, and analyzed by flow cytometry and PCR analyses. Some mice were given 3 intraperitoneal injections of a monoclonal antibody against IL17 or an isotype antibody (control). Livers from rhesus rota virus-infected mice with BA had 7-fold more Il17a messenger RNA than control mice (P= .02). γδ T cells were the exclusive source of IL17; no T-helper 17 cells were detected in livers of mice with BA. The increased number of IL17a-positive γδ T cells liver tissues of mice with BA was associated with increased levels of IL17A, IL17F, retinoid-orphan-receptor C, C-C chemokine receptor 6, and the IL23 receptor. Mice that were developing BA and given antibodies against IL17 had lower levels of liver inflammation and mean serum levels of bilirubin than mice receiving control antibodies (191 μmol/L vs 78 μmol/L, P= .002). Liver tissues from patients with BA had 4.6-fold higher levels of IL17 messenger RNA than control liver tissues (P= .02). In livers ofmice with BA, γδ T cells produce IL17, which is required for inflammation and destruction of the biliary system. IL17 is up-regulated in liver tissues from patients with BA, compared with controls, and might serve as a therapeutic target.