Immune mechanisms of Concanavalin A model of autoimmune hepatitis

Targeting GPR84 to alleviate acute immune-mediated liver injury

BACKGROUND

GPR84 is a Gi-coupled G-protein-coupled receptor (GPCR) predominantly expressed in immune cells, with its expression upregulated during inflammatory conditions. However, its specific role in immune-mediated liver injury remains unclear.

METHODS

We utilized a concanavalin A (Con A)-induced mouse model to simulate immune-mediated liver injury. The expression of GPR84 was assessed by quantitative RT-PCR and western blotting. GPR84 gene knockout mice were employed to evaluate the receptor's functional role. Bone marrow chimeric mice were created to determine the involvement of hematopoietic cells. Infiltrating liver inflammatory cells were analyzed by flow cytometry. The activation of key signaling pathways in hepatic tissues was assessed by western blotting. The GPR84 antagonist GLPG1205 was tested in this model to evaluate its therapeutic potential.

RESULTS

GPR84 expression was significantly upregulated in the mouse liver following Con A injection. Mice lacking GPR84 exhibited reduced serum ALT and AST levels, diminished liver damage, and decreased apoptosis. Additionally, the expression levels of inflammatory cytokines MCP-1 and TNF-α were significantly lower in Gpr84-/- mice compared to wild-type (WT) mice after Con A injection. Flow cytometry analysis revealed a notable reduction in the proportion of Kupffer cells and infiltrating monocytes (CD11b⁺Ly6ClowLy6G⁻) in Gpr84-/- mice. Using bone marrow chimeric mice, we demonstrated that GPR84-deficient bone marrow-derived cells mitigate Con A-induced liver injury. Furthermore, GPR84 deficiency was associated with reduced hepatic apoptosis and lower phosphorylation levels of STAT3, ERK, JNK, p38, and p65, effectively inhibiting key inflammatory signaling pathways. Importantly, treatment with the GPR84 antagonist GLPG1205 significantly lowered serum ALT and AST levels, reduced the expression of inflammatory cytokines, and alleviated liver damage.

CONCLUSIONS

Our findings suggest that GPR84 plays a pivotal role in immune-mediated liver injury, primarily through its expression on hematopoietic cells. Targeting GPR84, particularly with the antagonist GLPG1205, offers a promising therapeutic strategy for treating immune-related liver diseases.

Macrophage expression of constitutively active TβRI alleviates hepatic injury in a mouse model of concanavalin A-induced autoimmune hepatitis

Transforming growth factor-β (Tgf-β) contributes to the development of liver diseases through its regulation of various cell types. While Tgf-β signaling to hepatic stellate cells (HSCs) and hepatocytes was shown to mediate hepatic damage, the effect of Tgf-β on other cells in liver is yet to be clearly defined. Herein we identified a regulatory function of macrophage Tgf-β signaling in liver injury. We found that transgenic mice expressing constitutively active Tgf-β receptor type I (TβRI CA ) under the control of Fsp1-Cre (TβRI CA /Fsp1-Cre mice) were less susceptible to concanavalin A (conA)-induced autoimmune hepatitis. Liver tissue examination showed a decrease of necrotic area in conA-treated TβRI CA /Fsp1-Cre liver compared to those of wild-type mice. Blood test revealed that serum aminotransferases were significantly reduced in conA-treated TβRI CA /Fsp1-Cre mice as compared to those of wild-type mice. Immunohistochemistry for CD3 and myeloperoxidase demonstrated that there was a decreased accumulation of T cells and neutrophils, respectively, whereas ELISA showed that IL-4, IL-5, IL-10, IL-12 and IFN-γ was increased in livers of conA-treated TβRI CA /Fsp1-Cre mice. Alternatively activated macrophage (M2) polarization was significantly elevated in livers of conA-treated TβRI CA /Fsp1-Cre mice as indicated by enhanced hepatic expression of CCR2 and CD206 as well as increased numbers of liver macrophages expressing M2 subtype marker, CD163. qPCR analysis indicated an increased expression of TβRI CA , Arg1, Ym1, CD206, Snail1, Foxo1 and IRF4 as well as a decreased expression of MHC class II and CD1d in liver macrophages that were isolated from TβRI CA /Fsp1-Cre mice. Moreover, flow cytometry analysis showed a lower number of NKT cells in livers of conA-treated TβRI CA /Fsp1-Cre mice when compared to those of wild-type mice. In conclusion, Fsp1-Cre-mediated expression of TβRI CA lead to a decreased conA-induced liver injury that was associated with enhanced M2 macrophage polarization and reduced NKT cell recruitment.

Hepatoprotective Effect of Camel Thorn Polyphenols in Concanavalin A-Induced Hepatitis in Mice

OBJECTIVES

To explore the prophylactic and therapeutic effects of Alhagi maurorum ethanolic extract (AME) in concanavalin A (Con A)-induced hepatitis (CIH) as well as possible underlying mechanisms.

METHODS

Polyphenols in AME were characterized using high performance liquid chromatography (HPLC). Swiss albino mice were divided into 4 groups. Normal group received intravenous phosphate-buffered saline (PBS); Con A group received 40 mg/kg intravenous Con A. Prophylaxis group administered 300 mg/(kg·d) AME orally for 5 days before Con A intervention. Treatment group received intravenous Con A then administered 300 mg/kg AME at 30 min and 3 h after Con A intervention. After 24 h of Con A injection, hepatic injury, oxidative stress, and inflammatory mediators were assessed. Histopathological examination and markers of apoptosis, inflammation, and CD4+ cell infiltration were also investigated.

RESULTS

HPLC analysis revealed that AME contains abundant polyphenols with pharmacological constituents, such as ellagic acid, gallic acid, ferulic acid, methylgallate, and naringenin. AME alleviated Con A-induced hepatic injury, as manifested by a significant reduction in alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase (P<0.01). Additionally, the antioxidant effect of AME was revealed by a significant reduction in oxidative stress markers (nitric oxide and malondialdehyde) and restored glutathione (P<0.01). The levels of proinflammatory cytokines (tumor necrosis factor-α, interferon-γ, and interleukin-6) and c-Jun N-terminal kinase (JNK) activity were reduced (P<0.01). Histopathological examination of liver tissue showed that AME significantly ameliorated necrotic and inflammatory lesions induced by Con A (P<0.01). Moreover, AME reduced the expression of nuclear factor kappa B, pro-apoptotic protein (Bax), caspase-3, and CD4+ T cell hepatic infiltration (P<0.01). The expression of anti-apoptotic protein Bcl-2 was increased (P<0.01).

CONCLUSION

AME has hepatoprotective and ameliorative effects in CIH mice. These beneficial effects are likely due to the anti-inflammatory, antioxidant, and anti-apoptotic effects of the clinically important polyphenolic content. AME could be a novel and promising hepatoprotective agent for managing immune-mediated hepatitis.

Succinic Acid Ameliorates Concanavalin A-Induced Hepatitis by Altering the Inflammatory Microenvironment and Expression of BCL-2 Family Proteins

Autoimmune hepatitis (AIH) is a severe immune-mediated inflammatory liver disease that currently lacks feasible drug treatment methods. Our study aimed to evaluate the protective effect of succinic acid against AIH and provide a reliable method for the clinical treatment of AIH. We performed an in vivo study of the effects of succinic acid on concanavalin A (ConA)-induced liver injury in mice. We examined liver transaminase levels, performed hematoxylin and eosin (HE) staining, and observed apoptotic phenotypes in mice. We performed flow cytometry to detect changes in the number of neutrophils and monocytes, and used liposomes to eliminate the liver Kupffer cells and evaluate their role. We performed bioinformatics analysis, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and western blotting to detect mitochondrial apoptosis-induced changes in proteins from the B-cell lymphoma 2(Bcl-2) family. Succinic acid ameliorated ConA-induced AIH in a concentration-dependent manner, as reflected in the survival curve. HE and TUNEL staining and terminal deoxynucleotidyl transferase dUTP nick end labeling revealed decreased alanine transaminase and aspartate aminotransferase levels, and reduced liver inflammation and apoptosis. RT-qPCR and enzyme-linked immunosorbent assay revealed that succinic acid significantly reduced liver pro-inflammatory cytokine levels. Flow cytometry revealed significantly decreased levels of liver neutrophils. Moreover, the protective effect of succinic acid disappeared after the Kupffer cells were eliminated, confirming their important role in the effect. Bioinformatics analysis, RT-qPCR, and western blotting showed that succinic acid-induced changes in proteins from the Bcl-2 family involved mitochondrial apoptosis, indicating the molecular mechanism underlying the protective effect of succinic acid. Succinic acid ameliorated ConA-induced liver injury by regulating immune balance, inhibiting pro-inflammatory factors, and promoting anti-apoptotic proteins in the liver. This study provides novel insights into the biological functions and therapeutic potential of succinic acid in the treatment of autoimmune liver injury.

Sappanone A Ameliorates Concanavalin A-induced Immune-Mediated Liver Injury by Regulating M1 Macrophage Polarization

Sappanone A (SAP), a high-isoflavone compound derived from the traditional Chinese medicine Sumu, exhibits various pharmacological activities, including anti-inflammatory and anti-oxidant effects. However, its protective effects on the liver have rarely been reported. The aim of this study was to investigate the effects of SAP on immune-mediated liver injury induced by concanavalin A (Con A) in mice and to explore the underlying molecular mechanisms. Mice were administered SAP intraperitoneally (50 mg/kg body weight). Three hours later, Con A (18 mg/kg) was injected via the tail vein to induce liver damage. Livers and blood were collected 12 h after Con A challenge. Liver cell apoptosis, oxidative stress, and M1 macrophage activation in vivo were investigated. Bone marrow-derived macrophages were used to confirm the effects of SAP on M1 polarization in vitro. The results indicated that SAP decreased transaminase levels, inhibited apoptosis, and improved oxidative stress in mouse livers. Furthermore, SAP significantly reduced the proportion of macrophages, inhibited the expression of CD86, and downregulated the expression of M1 macrophage-related inflammatory cytokines. Moreover, SAP-treated macrophages alleviated liver damage caused by Con A compared to non-SAP-treated macrophages. Mechanistically, SAP inhibited the phosphorylation of key molecules in the MAPK and NF-κB signaling pathways in macrophages, resulting in an inhibitory effect on M1 macrophage activation. Taken together, SAP alleviates immune-mediated liver injury induced by Con A by suppressing M1 macrophage polarization, which is partially associated with NF-κB and MAPK signaling pathways.

Rhoifolin Attenuates Concanavalin A-Induced Autoimmune Hepatitis in Mice via JAKs/STATs Mediated Immune and Apoptotic Processes

Rhoifolin (ROF) exhibits a diverse range of biological activities, encompassing anticancer, hepatoprotective, antidiabetic, antirheumatic, and antiviral properties. However, the specific protective effects and possible mechanisms of the compound against T-cell-mediated autoimmune hepatitis have not been previously elucidated. In the present study, adult male mice were administered Con A (20 mg/kg, intravenously) for 8 h. In the treated groups, mice were pretreated with ROF daily (20 mg/kg and 40 mg/kg, orally) for 7 days before Con A intoxication. The results showed that ROF significantly decreased serum biochemical indices (ALT, AST, ALP, and LDH) and regulated related oxidative stress indicators (MDA, SOD, and GSH), reduced hepatic necrosis areas and immune cells infiltration, inhibited the release of various inflammatory factors (TNF-α, IFN-γ, IL-2, and IL-17), and improved hepatic tissue apoptosis, thereby alleviating hepatic damage induced by Con A. Additionally, we have also confirmed that ROF efficiently inhibited Th1/Th17 cells polarization via modulation of the JAK2/JAK3/STAT1/STAT3 signaling pathways both in vivo and in vitro. Moreover, the molecular mechanism examination also demonstrated that ROF regulated apoptotic cascade signaling through IL-6/JAK2/STAT1/STAT3 controlling BNIP3 activity in primary hepatocytes. These effects were in good agreement with the bioinformatics analysis of ROF treatment for AIH. In conclusion, our findings provide new insights into the potential use of ROF for AIH therapy, which may result from the specific regulation of the T cell subtype polarization and the apoptosis of liver cells via modulation of the JAKs/STATs signaling pathways.

Intracellular osteopontin potentiates the immunosuppressive activity of mesenchymal stromal cells

INTRODUCTION

Mesenchymal stromal cell (MSC)-based cell therapy is a promising approach for various inflammatory disorders based on their immunosuppressive capacity. Osteopontin (OPN) regulates several cellular functions including tissue repair, bone metabolism and immune reaction. However, the biological function of OPN in regulating the immunosuppressive capacity of MSCs remains elusive.

OBJECTIVES

This study aims to highlight the underlying mechanism of the proinflammatory cytokines affect the therapeutic ability of MSCs through OPN.

METHODS

MSCs in response to the proinflammatory cytokines were collected to determine the expression profile of OPN. In vitro T-cell proliferation assays and gene editing were performed to check the role and mechanisms of OPN in regulating the immunosuppressive capacity of MSCs. Inflammatory disease mouse models were established to evaluate the effect of OPN on improving MSC-based immunotherapy.

RESULTS

We observed that OPN, including its two isoforms iOPN and sOPN, was downregulated in MSCs upon proinflammatory cytokine stimulation. Interestingly, iOPN, but not sOPN, greatly enhanced the immunosuppressive activity of MSCs on T-cell proliferation and thus alleviated the inflammatory pathologies of hepatitis and colitis. Mechanistically, iOPN interacted with STAT1 and mediated its deubiquitination, thereby inducing the master immunosuppressive mediator inducible nitric oxide synthase (iNOS) in MSCs. In addition, iOPN expression was directly downregulated by activated STAT1, which formed a negative feedback loop to restrain MSC immunosuppressive capacity.

CONCLUSION

Our findings demonstrated that iOPN expression modulation in MSCs is a novel strategy to improve MSC-based immunotherapy.

GPR124 promotes trophoblast proliferation, migration, and invasion and inhibits trophoblast cell apoptosis and inflammation via JNK and P38 MAPK pathways

Early-onset preeclampsia, which occurrs before 34 weeks of gestation, is the most dangerous classification of preeclampsia, which is a pregnancy-specific disease that causes 1% of maternal deaths. G protein-coupled receptor 124 (GPR124) is significantly expressed at various stages of the human reproductive process, particularly during embryogenesis and angiogenesis. Our prior investigation demonstrated a notable decrease in GPR124 expression in the placentas of patients with early-onset preeclampsia compared to that in normal pregnancy placentas. However, there is a lack of extensive investigation into the molecular processes that contribute to the role of GPR124 in placenta development. This study aimed to examine the mechanisms by which GPR124 affects the occurrence of early-onset preeclampsia and its function in trophoblast. Proliferative, invasive, migratory, apoptotic, and inflammatory processes were identified in GPR124 knockdown, GPR124 overexpression, and normal HTR8/SVneo cells. The mechanism of GPR124-mediated cell function in GPR124 knockdown HTR8/SVneo cells was examined using inhibitors of the JNK or P38 MAPK pathway. Downregulation of GPR124 was found to significantly inhibit proliferation, invasion and migration, and promote apoptosis of HTR8/SVneo cells when compared to the control and GPR124 overexpression groups. This observation is consistent with the pathological characteristics of preeclampsia. In addition, GPR124 overexpression inhibits the secretion of pro-inflammatory cytokines interleukin (IL)-8 and interferon-γ (IFN-γ) while enhancing the secretion of the anti-inflammatory cytokine interleukin (IL)-4. Furthermore, GPR124 suppresses the activation of P-JNK and P-P38 within the JNK/P38 MAPK pathway. The invasion, apoptosis, and inflammation mediated by GPR124 were partially restored by suppressing the JNK and P38 MAPK pathways in HTR8/SVneo cells. GPR124 plays a crucial role in regulating trophoblast proliferation, invasion, migration, apoptosis, and inflammation via the JNK and P38 MAPK pathways. Furthermore, the effect of GPR124 on trophoblast suggests its involvement in the pathogenesis of early-onset preeclampsia.

Therapeutic potential of oleanolic acid in liver diseases

Liver-associated diseases affect millions of individuals worldwide. In developed countries, the incidence of viral hepatitis is reducing due to advancements in disease prevention, diagnosis, and treatment. However, with improvements in living standards, the prevalence of metabolic liver diseases, such as non-alcoholic fatty liver disease and alcohol-related liver disease, is expected to increase; notably, this rise in the prevalence of metabolic liver disease can lead to the development of more severe liver diseases, including liver failure, cirrhosis, and liver cancer. The growing demand for natural alternative therapies for chronic diseases has highlighted the importance of studying the pharmacology of bioactive compounds in plants. One such compound is oleanolic acid (OA), a pentacyclic triterpenoid known for its antioxidant, anti-inflammatory, anti-ulcer, antibacterial, antiviral, antihypertensive, anti-obesity, anticancer, anti-diabetic, cardioprotective, hepatoprotective, and anti-neurodegenerative properties. Recent studies have demonstrated that OA treatment can reduce the risk of pathological liver damage, ultimately alleviating liver dysregulation and restoring overall liver function. This review aims to explore the latest research on the biological effects of OA and its derivatives. Notably, it explores the mechanisms of action of these compounds in both in vitro and in vivo research models and, ultimately, highlights OA as a promising candidate for alternative therapies in the treatment and management of chronic liver disease.

Controlling autoimmune diabetes onset by targeting Protease-Activated Receptor 2

BACKGROUND

Type 1 diabetes (T1D) is a challenging autoimmune disease, characterized by an immune system assault on insulin-producing β-cells. As insulin facilitates glucose absorption into cells and tissues, β-cell deficiency leads to elevated blood glucose levels on one hand and target-tissues starvation on the other. Despite efforts to halt β-cell destruction and stimulate recovery, success has been limited. Our recent investigations identified Protease-Activated Receptor 2 (Par2) as a promising target in the battle against autoimmunity. We discovered that Par2 activation's effects depend on its initial activation site: exacerbating the disease within the immune system but fostering regeneration in affected tissue.

METHODS

We utilized tissue-specific Par2 knockout mice strains with targeted Par2 mutations in β-cells, lymphocytes, and the eye retina (as a control) in the NOD autoimmune diabetes model, examining T1D onset and β-cell survival.

RESULTS

We discovered that Par2 expression within the immune system accelerates autoimmune processes, while its presence in β-cells offers protection against β-cell destruction and T1D onset. This suggests a dual-strategy treatment for T1D: inhibiting Par2 in the immune system while activating it in β-cells, offering a promising strategy for T1D.

CONCLUSIONS

This study highlights Par2's potential as a drug target for autoimmune diseases, particularly T1D. Our results pave the way for precision medicine approaches in treating autoimmune conditions through targeted Par2 modulation.

Par2-mediated responses in inflammation and regeneration: choosing between repair and damage

The protease activated receptor 2 (Par2) plays a pivotal role in various damage models, influencing injury, proliferation, inflammation, and regeneration. Despite extensive studies, its binary roles- EITHER aggravating injury or promoting recovery-make a conclusive translational decision on its modulation strategy elusive. Analyzing two liver regeneration models, autoimmune hepatitis and direct hepatic damage, we discovered Par2's outcome depends on the injury's nature. In immune-mediated injury, Par2 exacerbates damage, while in direct tissue injury, it promotes regeneration. Subsequently, we evaluated the clinical significance of this finding by investigating Par2's expression in the context of autoimmune diabetes. We found that the absence of Par2 in all lymphocytes provided full protection against the autoimmune destruction of insulin-producing β-cells in mice, whereas the introduction of a β-cell-specific Par2 null mutation accelerated the onset of autoimmune diabetes. This pattern led us to hypothesize whether these observations are universal. A comprehensive review of recent Par2 publications across tissues and systems confirms the claim drafted above: Par2's initial activation in the immune system aggravates inflammation, hindering recovery, whereas its primary activation in the damaged tissue fosters regeneration. As a membrane-anchored receptor, Par2 emerges as an attractive drug target. Our findings highlight a crucial translational modulation strategy in regenerative medicine based on injury type.

Curdlan-Decorated Fullerenes Mitigate Immune-Mediated Hepatic Injury for Autoimmune Hepatitis Therapeutics via Reducing Macrophage Infiltration

Autoimmune hepatitis (AIH) is a severe immune-mediated inflammatory liver disease whose standard of care is immunosuppressive treatment with inevitable undesired outcomes. Macrophage is acknowledged to aggravate liver damage, providing a promising AIH therapeutic target. Accordingly, in this study, a kind of curdlan-decorated fullerene nanoparticle (Cur-F) is fabricated to alleviate immune-mediated hepatic injury for treating AIH via reducing macrophage infiltration in a concanavalin A (Con A)-induced AIH mouse model. After intravenous administration, Cur-F primarily distributes in liver tissues, efficiently eliminates the excessive reactive oxygen species, significantly attenuates oxidative stress, and subsequently suppresses the nuclear factor kappa-B-gene binding (NF-κB) signal pathway, resulting in the lowered production of pro-inflammatory cytokines and the balancing of the immune homeostasis with the prevention of macrophage infiltration in the liver. The regulation of hepatic inflammation contributes to inhibiting inflammatory cytokines-induced hepatocyte apoptosis, decreasing the serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) contents and thus ameliorating immune-mediated hepatic injury. Notably, there is no detectable toxicity to the body. Our findings may open up novel avenues for AIH based on curdlan and fullerene materials.

Nuezhenoside G13 from Osmanthus fragrans fruit ameliorates Concanavalin A-induced autoimmune hepatitis by regulating the NF-κB/MAPK pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Osmanthus fragrans fruit (OFF) exhibits hepatoprotective function, and it is consumed as food and used in traditional medicine in China. Nuezhenoside G13 (G13) is present in the highest levels in OFF. Autoimmune hepatitis (AIH) is a manifestation of liver disease and seriously endangers health. However, it remains unclear whether G13 affects AIH.

AIM OF THE STUDY

To clarify the effect of G13 on AIH and its exact underlying mechanism from a new perspective.

MATERIALS AND METHODS

We used a Concanavalin A-induced AIH mouse model and lipopolysaccharide-treated Raw264.7 cells to quantify serum biochemical indicators and confirm whether G13 exhibited protective effects in the AIH mice. Furthermore, we evaluated the effect of G13 via hematoxylin and eosin and immunohistochemical staining. We used enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction to quantify the inflammatory factors. We confirmed that G13 inhibited apoptosis via terminal deoxynucleotidyl transferase dUTP nick end labeling staining. Molecular docking, immunofluorescence, and western blotting experiments of G13 and key proteins of the NF-κB/MAPK pathway revealed that G13 alleviated inflammation. In addition, Cell Counting Kit-8, ELISA, NO detection, and western blotting assays were performed. Finally, we used an inhibitor of the p38 MAPK to verify that G13 reduced inflammation through the NF-κB/MAPK pathway in Raw264.7 cells.

RESULTS

The in vivo experiments revealed that G13 improved oxidative stress and apoptosis. In addition, G13 decreased the expression levels of CD4+, CD8+, F4/80+, and Ly6G and the secretion of inflammatory factors. Interestingly, G13 reduced the phosphorylation levels of IκBα, NF-κB, JNK, ERK1/2, and p38. Additionally, the in vitro experiments revealed that G13 alleviated inflammation through the NF-κB/MAPK pathway in lipopolysaccharide-treated Raw264.7 cells. Furthermore, molecular docking demonstrated that the binding fraction of G13 with these proteins was high.

CONCLUSION

G13 suppressed oxidative stress, apoptosis, and inflammation in a Concanavalin A-induced AIH mouse model. Furthermore, G13 exerted its effect through the NF-κB/MAPK pathway.

Enhancing Liver Delivery of Gold Nanoclusters via Human Serum Albumin Encapsulation for Autoimmune Hepatitis Alleviation

Peptide-protected gold nanoclusters (AuNCs), possessing exceptional biocompatibility and remarkable physicochemical properties, have demonstrated intrinsic pharmaceutical activity in immunomodulation, making them a highly attractive frontier in the field of nanomedicine exploration. Autoimmune hepatitis (AIH) is a serious autoimmune liver disease caused by the disruption of immune balance, for which effective treatment options are still lacking. In this study, we initially identified glutathione (GSH)-protected AuNCs as a promising nanodrug candidate for AIH alleviating in a Concanavalin A (Con A)-induced mice model. However, to enhance treatment efficiency, liver-targeted delivery needs to be improved. Therefore, human serum albumin (HSA)-encapsulated AuNCs were constructed to achieve enhanced liver targeting and more potent mitigation of Con A-induced elevations in plasma aspartate transaminase (AST), alanine transaminase (ALT), and liver injury in mice. In vivo and in vitro mechanism studies indicated that AuNCs could suppress the secretion of IFN-γ by Con A-stimulated T cells and subsequently inhibit the activation of the JAK2/STAT1 pathway and eventual hepatocyte apoptosis induced by IFN-γ. These actions ultimately protect the liver from immune cell infiltration and damage caused by Con A. These findings suggest that bio-protected AuNCs hold promise as nanodrugs for AIH therapy, with their liver targeting capabilities and therapeutic efficiency being further improved via rational surface ligand engineering.

Pemetrexed ameliorates Con A-induced hepatic injury by restricting M1 macrophage activation

Autoimmune hepatitis (AIH), characterized by immune-driven liver destruction and cytokine production, is a progressive inflammatory liver condition that may progress to hepatic cirrhosis or tumors. However, the underlying mechanism is not well understood, and the treatment options for this disease are limited. Pemetrexed (PEM), a clinically used anti-folate drug for treating various tumors, was found to inhibit the nuclear factor (NF)-κB signaling pathways that exert an important role in the development of AIH. Here, we investigated the impact of PEM on immune-mediated hepatic injuries using a murine model of Concanavalin A (Con A)-induced hepatitis, a well-established model for AIH. Mice received intraperitoneal PEM injections 3 times at 12-hour intervals, and two hours later, they were challenged with Con A. Liver samples and serum were collected after 10 h. The results indicate that PEM significantly improved mouse survival rates and lowered serum transaminase levels. Moreover, PEM effectively alleviated oxidative stress, reduced histopathological liver damage, and mitigated hepatocyte apoptosis. Notably, it reduced the activation of M1-type macrophages in the liver. The expression of proinflammatory cytokines and genes associated with M1 macrophages, such as tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, IL-12, IL-1β, and inducible nitric oxide synthase (iNOS), was also decreased. Finally, the results indicated that PEM regulates M1 macrophage activation by modulating the NF-κB signaling pathways. Overall, these results demonstrate that PEM effectively guards against immune-mediated hepatic injuries induced by Con A by inhibiting M1 macrophage activation through the NF-κB signaling pathways and indicate the potential of PEM as a practical treatment option for AIH in clinical settings.

TPN10475 alleviates concanavalin A-induced autoimmune hepatitis by limiting T cell development and function through inhibition of PI3K-AKT pathway

Autoimmune hepatitis (AIH) is an inflammatory liver disease in which the autoimmune system instigates an attack on the liver, causing inflammation and liver injury, and its incidence has increased worldwide in recent years. The mouse model of acute hepatitis established by concanavalin A (Con A) is a typical and recognized mouse model for the study of T-cell-dependent liver injury. In this study, we aimed to investigate whether the artemisinin derivative TPN10475 could alleviate AIH and its possible mechanisms. TPN10475 effectively inhibited lymphocyte proliferation and IFN-γ+ T cells production in vitro, alleviated liver injury by decreasing infiltrating inflammatory T cells producing IFN-γ in the liver and peripheral immune tissues, and demonstrated that TPN10475 weakened the activation and function of T cells by inhibiting PI3K-AKT signaling pathway. These results suggested that TPN10475 may be a potential drug for the treatment of AIH, and the inhibition of PI3K-AKT signaling pathway may provide new ideas for the study of the pathogenesis of AIH.

Prenyllongnols A-D, New Prenylated Acylphloroglucinols that Fight Concanavalin A-Induced Autoimmune Hepatitis

Autoimmune hepatitis is a serious hepatic disorder with unknown nosogenesis, and natural products have been deemed to be one of the most significant sources of new drugs against this disease. Prenyllongnols A-D (1-4), four undescribed prenylated acylphloroglucinols, were isolated from Hypericum longistylum. Compounds 1-4 exhibited remarkable immunosuppressive activities in murine splenocyte proliferation under the induction of concanavalin A (Con A), and IC50 values ranged from 2.98 ± 0.21 to 6.34 ± 0.72 μM. Furthermore, in a Con A-challenged autoimmune hepatitis mouse model, the mice in the group that were pretreated with isolate 2 significantly ameliorated liver injury and decreased proinflammatory cytokine production. Notably, natural product 2 was the first prenylated acylphloroglucinol to protect against concanavalin A-induced autoimmune hepatitis. This finding underscores the potential of prenylated acylphloroglucinol-type metabolites as promising candidates for designing novel immunosuppressors in the quest for new antiautoimmune hepatitis drugs.

Nitric oxide-dependent immunosuppressive function of thymus-derived mesenchymal stromal/stem cells

BACKGROUND

The thymus is required for T cell development and the formation of the adaptive immunity. Stromal cells, which include thymic epithelial cells (TECs) and mesenchymal stromal cells (MSCs), are essential for thymic function. However, the immunomodulatory function of thymus-derived MSCs (T-MSCs) has not been fully explored.

METHODS

MSCs were isolated from mouse thymus and their general characteristics including surface markers and multi-differentiation potential were characterized. The immunomodulatory function of T-MSCs stimulated by IFN-γ and TNF-α was evaluated in vitro and in vivo. Furthermore, the spatial distribution of MSCs in the thymus was interrogated by using tdTomato-flox mice corssed to various MSC lineage Cre recombinase lines.

RESULTS

A subset of T-MSCs express Nestin, and are mainly distributed in the thymic medulla region and cortical-medulla junction, but not in the capsule. The Nestin-positive T-MSCs exhibit typical immunophenotypic characteristics and differentiation potential. Additionally, when stimulated with IFN-γ and TNF-α, they can inhibit activated T lymphocytes as efficiently as BM-MSCs, and this function is dependent on the production of nitric oxide (NO). Additionally, the T-MSCs exhibit a remarkable therapeutic efficacy in acute liver injury and inflammatory bowel disease (IBD).

CONCLUSIONS

Nestin-positive MSCs are mainly distributed in medulla and cortical-medulla junction in thymus and possess immunosuppressive ability upon stimulation by inflammatory cytokines. The findings have implications in understanding the physiological function of MSCs in thymus.

Hippo Pathway Activation in Aged Mesenchymal Stem Cells Contributes to the Dysregulation of Hepatic Inflammation in Aged Mice

Aging is always accompanied by chronic diseases which probably attribute to long-term chronic inflammation in the aging body. Whereas, the mechanism of chronic inflammation in aging body is still obscure. Mesenchymal stem cells (MSCs) are capable of local chemotaxis to sites of inflammation and play a powerful role in immune regulation. Whether degeneration of MSCs in the aging body is associated with unbalanced inflammation is still not clear. In this study, immunosuppressive properties of aged MSCs are found to be repressed. The impaired immunosuppressive function of aged MSCs is associated with lower expression of the Hippo effector Yes-associated protein 1 (YAP1) and its target gene signal transducer and activator of transcription 1 (STAT1). YAP1 regulates the transcription of STAT1 through binding with its promoter. In conclusion, a novel YAP1/STAT1 axis maintaining immunosuppressive function of MSCs is revealed and impairment of this signal pathway in aged MSCs probably resulted in higher inflammation in aged mice liver.

Purinergic receptor P2Y12 boosts autoimmune hepatitis through hexokinase 2-dependent glycolysis in T cells

Increasing evidence suggests that immunometabolism has started to unveil the role of metabolism in shaping immune function and autoimmune diseases. In this study, our data show that purinergic receptor P2Y12 (P2RY12) is highly expressed in concanavalin A (ConA)-induced immune hepatitis mouse model and serves as a potential metabolic regulator in promoting metabolic reprogramming from oxidative phosphorylation to glycolysis in T cells. P2RY12 deficiency or inhibition of P2RY12 with P2RY12 inhibitors (clopidogrel and ticagrelor) are proved to reduce the expression of inflammatory mediators, cause CD4⁺ and CD8⁺ effector T cells hypofunction and protect the ConA-induced immune hepatitis. A combined proteomics and metabolomics analysis revealed that P2RY12 deficiency causes redox imbalance and leads to reduced aerobic glycolysis by downregulating the expression of hexokinase 2 (HK2), a rate-limiting enzyme of the glycolytic pathway, indicating that HK2 might be a promising candidate for the treatment of diseases associated with T cell activation. Further analysis showed that P2RY12 prevents HK2 degradation by activating the PI3K/Akt pathway and inhibiting lysosomal degradation. Our findings highlight the importance of the function of P2RY12 for HK2 stability and metabolism in the regulation of T cell activation and suggest that P2RY12 might be a pivotal regulator of T cell metabolism in ConA-induced immune hepatitis.

Meteorin-like protein overexpression ameliorates fulminant hepatitis in mice by inhibiting chemokine-dependent immune cell infiltration

Myokines, which are recently identified cytokines secreted by skeletal muscle in response to stimulation, are crucial for the maintenance of liver function. Fulminant hepatitis (FH) is a life-threatening pathological condition with severe hepatic dysfunction. In this study, we investigated the role of meteorin-like (METRNL), a new myokine, in the pathogenesis of FH. We compared serum samples and liver tissues from FH patients and healthy controls and found that hepatic and serum METRNL levels were significantly increased in FH patients, and serum METRNL levels were related to disease severity in FH patients. We then established a concanavalin A-induced FH model in METRNL-overexpressing and control mice. We found that hepatic METRNL levels in FH mice were significantly increased, and METRNL in the liver was mainly derived from macrophages. In the cultured mouse macrophage line (RAW264.7 cells) and mouse primary peritoneal macrophages (PMs), METRNL overexpression significantly inhibited the release of the proinflammatory cytokines TNF and IL-1β. In METRNL-overexpressing mice, concanavalin A-induced liver injury was significantly ameliorated. Moreover, METRNL overexpression significantly reduced chemokine-dependent inflammatory cell infiltration into the liver. METRNL overexpression also suppressed liver CD4+ T cell differentiation into Th 1 cells and inhibited the secretion of Th 1 cytokines. Taken together, these data suggest that METRNL overexpression effectively ameliorates FH. Therefore, METRNL may serve as a potential biomarker and therapeutic target for FH.

Celecoxib abrogates concanavalin A-induced hepatitis in mice: Possible involvement of Nrf2/HO-1, JNK signaling pathways and COX-2 expression

Concanavalin A (ConA) is an established model for inducing autoimmune hepatitis (AIH) in mice, mimicking clinical features in human. The aimof the current study is to explore the possible protective effect of celecoxib, a cyclooxygenase-2 inhibitor,on immunological responses elicited in the ConA model of acute hepatitis. ConA (20 mg/kg) was administered intravenously to adult male mice for 6 h. Prior to ConA intoxication, mice in the treatedgroups received daily doses of celecoxib (30 and 60 mg/kg in CMC) for 7 days. Results revealed that administration of celecoxib 60 mg/kg for 7 days significantly protected the liver from ConA-induced liver damage revealed by significant decrease in ALT and AST serum levels. Celecoxib 30 and 60 mg/kg pretreatment enhanced oxidant/antioxidant hemostasis by significantreduction of MDA and NO content and increase hepatic GSH contents and SOD activity. In addition, celecoxib 30 and 60 mg/kg caused significant increase in hepatic nuclear factor erythroid 2-related factor 2 (Nrf2) and the stress protein heme oxygenase-1 (HO-1) levels. Moreover, celecoxib 30 and 60 mg/kg inhibited the release of proinflammatory markers including IL-1β and TNF-α along with significant decrease in p-JNK, AKT phosphorylation ratio and caspase-3 expression. Besides, Con A was correlated to high expression of cyclooxygenase COX-2 and this increasing was improved by administration of celecoxib. These changes were in good agreement with improvement in histological deterioration. The protective effect of celecoxib was also associated with significant reduction of autophagy biomarkers (Beclin-1 and LC3II). In conclusion, celecoxib showed antioxidant, anti-inflammatory, anti-apoptotic and anti-autophagy activity against Con A-induced immune-mediated hepatitis. These effects could be produced by modulation of Nrf2/HO-1, IL-1B /p-JNK/p-AKT, JNK/caspase-3, and Beclin-1/LC3II signaling pathways.

Human menstrual blood-derived stem cells alleviate autoimmune hepatitis via JNK/MAPK signaling pathway in vivo and in vitro

Autoimmune hepatitis (AIH) is a severe globally distributed liver disease that could occur at any age. Human menstrual blood-derived stem cells (MenSCs) have shown therapeutic effect in acute lung injury and liver failure. However, their role in the curative effect of AIH remains unclear. Here, a classic AIH mouse model was constructed through intravenous injection with concanavalin A (Con A). MenSCs were intravenously injected while Con A injection in the treatment groups. The results showed that the mortality by Con A injection was significantly decreased by MenSCs treatment and liver function tests and histological analysis were also ameliorated. The results of phosphoproteomic analysis and RNA-seq revealed that MenSCs improved AIH, mainly by apoptosis and c-Jun N-terminal kinase/mitogen-activated protein signaling pathways. Apoptosis analysis demonstrated that the protein expression of cleaved caspase 3 was increased by Con A injection and reduced by MenSCs transplantation, consistent with the TUNEL staining results. An AML12 co-culture system and JNK inhibitor (SP600125) were used to verify the JNK/MAPK and apoptosis signaling pathways. These findings suggested that MenSCs could be a promising strategy for AIH.

Toll-like receptor-7 signaling in Kupffer cells exacerbates concanavalin A-induced liver injury in mice

Concanavalin A (ConA) is a plant lectin that can induce immune-mediated liver damage. ConA induced liver damage animal model is a widely accepted model that can mimic clinical acute hepatitis and immune-mediated liver injury in humans. Toll-like receptor-7 (TLR7), a member of the TLR family, plays a key role in pathogen recognition and innate immune activation. The aim of this study was to examine the role of TLR7 in the pathogenesis of ConA-induced liver injury. Acute liver injury was induced by intravenous injection with ConA in WT (wild-type) and TLR7 knockout (KO) mice. Results showed that attenuated liver injury in TLR7-deficient mice, as indicated by increased survival rate, decreased aminotransferase levels, and reduced pathological lesions, was associated with decreased release of pro-inflammatory cytokines in livers. Consistently, significantly decreased proliferation of CD4⁺ T cell was detected in ConA-stimulated TLR7-deficient splenocytes, but not in CD3/CD28 stimulated TLR7-deficient CD4⁺ T cells. Moreover, TLR7 deficiency in KCs specifically suppressed the expression of TNF-α (tumor necrosis factor-α). Depletion of KCs abolished the detrimental role of TLR7 in ConA-induced liver injury. Taken together, these results demonstrate that TLR7 can regulate the expression of TNF-α in KCs, which is necessary for the full progression of ConA-induced liver injury.

Hepatocyte estrogen sulfotransferase inhibition protects female mice from concanavalin A-induced T cell-mediated hepatitis independent of estrogens

Autoimmune hepatitis (AIH) is a typical T cell-mediated chronic liver disease with a higher incidence in females. However, the molecular mechanism for the female predisposition is poorly understood. Estrogen sulfotransferase (Est) is a conjugating enzyme best known for its function in sulfonating and deactivating estrogens. The goal of this study is to investigate whether and how Est plays a role in the higher incidence of AIH in females. Concanavalin A (ConA) was used to induce T cell-mediated hepatitis in female mice. We first showed that Est was highly induced in the liver of ConA-treated mice. Systemic or hepatocyte-specific ablation of Est, or pharmacological inhibition of Est, protected female mice from ConA-induced hepatitis regardless of ovariectomy, suggesting the effect of Est inhibition was estrogen independent. In contrast, we found that hepatocyte-specific transgenic reconstitution of Est in the whole-body Est knockout (EstKO) mice abolished the protective phenotype. Upon the ConA challenge, EstKO mice exhibited a more robust inflammatory response with elevated production of proinflammatory cytokines and changed liver infiltration of immune cells. Mechanistically, we determined that ablation of Est led to the hepatic induction of lipocalin 2 (Lcn2), whereas ablation of Lcn2 abolished the protective phenotype of EstKO females. Our findings demonstrate that hepatocyte Est is required for the sensitivity of female mice to ConA-induced and T cell-mediated hepatitis in an estrogen-independent manner. Est ablation may have protected female mice from ConA-induced hepatitis by upregulating Lcn2. Pharmacological inhibition of Est might be a potential strategy for the treatment of AIH.

Potential of HMGB-inhibitory oligodeoxynucleotide ISM ODN to neutrophil recruitment in mouse model of hepatitis

High-mobility group box 1 (HMGB1) is a nucleotide-binding chromatin protein that has also been characterized as a prototypical damage-associate molecular pattern. It triggers inflammatory responses upon release from damaged or dying cells. In fact, HMGB1 has been linked to the induction of many inflammatory diseases through immune cell activation including neutrophil recruitment. In this study, we examined the impact of HMGB1-binding inhibitory oligodeoxynucleotide (ISM ODN) on the development of hepatitis using a murine model of the disease. Our results indicate that ISM ODN effectively suppresses pathological features of hepatitis, including neutrophil accumulation. This study therefore may offer clinical insight into the treatment of hepatitis and possibly other inflammatory diseases.

New Insight into the Concanavalin A-Induced Apoptosis in Hepatocyte of an Animal Model: Possible Involvement of Caspase-Independent Pathway

Concanavalin A (Con A) is known to be a T-cell mitogen and has been shown to induce hepatitis in mice through the triggering of conventional T cells and NKT cells. However, it remains unknown whether Con A itself can directly induce rapid hepatocyte death in the absence of a functional immune system. Here, by using an immunodeficient mouse model, we found Con A rapidly induced liver injury in vivo despite a lack of immunocyte involvement. We further observed in vitro that hepatocytes underwent a dose-dependent but caspase-independent apoptosis in response to Con A stimulation in vitro. Moreover, transcriptome RNA-sequencing analysis revealed that apoptosis pathways were activated in both our in vivo and in vitro models. We conclude that Con A can directly induce rapid but non-classical apoptosis in hepatocytes without the participation of immunocytes. These findings provide new insights into the mechanism of Con A-induced hepatitis.

Construction and function analysis of the LncRNA-miRNA-mRNA competing endogenous RNA network in autoimmune hepatitis

AIMS

To construct the lncRNA-miRNA-mRNA competing endogenous RNA (ceRNA) network based on our microarray chip data for providing new insights into the pathogenesis of autoimmune hepatitis.

METHODS

The ceRNA pairs were obtained by calculating the co-expression relationships among the differentially expressed lncRNAs (DELs), differentially expressed microRNAs (DEMis), and differentially expressed mRNAs (DEMs) with Pearson correlation analysis and hypergeometric distribution. The data of the differentially expressed genes were obtained from our previous studies in the concanavalin A-induced AIH mouse model. The biological functions of the ceRNA network were revealed by carrying out the GO and KEGG enrichment analysis. The expression of some differentially expressed genes constructed in the ceRNA pair was validated, and the correlation to liver injury was analyzed.

RESULTS

The mRNAs constructed in the ceRNA network were most significantly annotated in the GO terms of "inflammatory response" and enriched in "Cytokine-cytokine receptor interaction" and "MAPK signaling pathway". The differences in the expression of Gm38975, mmu-miR-125a-3p, and Map3k13 between the model group and control group were significant, and the expression of these genes at a transcriptional level was positively or negatively correlated to the activity of ALT and AST as well as the amount of MDA and NO.

CONCLUSION

Our work is the first in its kind to predict and illustrate the comprehensive lncRNA-miRNA-mRNA ceRNA network associated with the etiopathogenesis of AIH. This study indicates to lay the foundation for revealing the potential roles of ceRNAs in the occurrence of AIH and provide novel treatment targets for this disease.

Garcinone E Mitigates Oxidative Inflammatory Response and Protects against Experimental Autoimmune Hepatitis via Modulation of Nrf2/HO-1, NF-κB and TNF-α/JNK Axis

Garcinia mangostana L. (Clusiaceae), a popular tropical fruit for its juiciness and sweetness, is an opulent fountain of prenylated and oxygenated xanthones with a vast array of bio-activities. Garcinone E (GE), a xanthone derivative reported from G. mangostana, possesses cytotoxic and aromatase inhibitory activities. The present research endeavors to investigate the hepato-protection efficaciousness of GE on concanavalin-A (Con-A)-instigated hepatitis. Results showed that GE pretreating noticeably diminishes both the serum indices (transaminases, ALP, LDH, and γ-GT) and histopathological lesions of the liver. It counteracted neutrophil and CD4+ infiltration into the liver. GE furthered the Nrf2 genetic expression and its antioxidants' cascade, which resulted in amelioration of Con-A-caused oxidative stress (OS), lipid per-oxidative markers (4-HNE, MDA, PC) reduction, and intensified antioxidants (TAC, SOD, GSH) in the hepatic tissue. Additionally, GE prohibited NF-ĸB (nuclear factor kappa-B) activation and lessened the genetics and levels of downstream cytokines (IL1β and IL6). Moreover, the TNF-α/JNK axis was repressed in GE-treated mice, which was accompanied by attenuation of Con-A-induced apoptosis. These findings demonstrated the protective potential of GE in Con-A-induced hepatitis which may be associated with Nrf2/HO-1 signaling activation and OS suppression, as well as modulation of the NF-κB and TNF-α/JNK/apoptosis signaling pathway. These results suggest the potential use of GE as a novel hepato-protective agent against autoimmune hepatitis.

Narciclasine ameliorated T cell mediated acute liver injury through activating AMPK pathway

Hepatitis is closely related to cirrhosis and liver cancer, and it is vital that we develop new drugs and identify new drug targets. Traditional Chinese medicine has demonstrated excellent curative effects on liver diseases. The ingredients from Chinese herbals are important source for drug development in the treatment of hepatitis. Here, we found that narciclasine (NCS), a major component extracted from narcissus bulbs, showed hepatoprotective effect against concanavalin A (Con A) induced hepatitis. NCS treatment significantly reduced hepatocyte death, hepatic inflammatory cells infiltration, and serum cytokine levels in Con A challenged mice. We further observed that NCS directly inhibited Con A induced splenocytes proliferation and cytokine production in vitro. RNA-seq results showed that genes related to immune response were upregulated in Con A treated CD4+ T cells, which were down-regulated in the presence of NCS. Moreover, the AMPK pathway had been found activated in response to NCS treatment, suggesting a potential target for NCS targets. In conclusion, our results reveal that NCS is a powerful immunosuppressor against T cell activation, thus leading to protection against Con A induced liver injury in mice. These findings provide new insights into the use of natural products in the treatment of autoimmune hepatitis.

Resolving the conflicts around Par2 opposing roles in regeneration by comparing immune-mediated and toxic-induced injuries

BACKGROUND

Different factors may lead to hepatitis. Among which are liver inflammation and poisoning. We chose two hepatitis models, typical for these two underlying causes. Thus, we aimed to characterize the role of protease-activated receptor 2 (Par2) in liver regeneration and inflammation to reconcile Par2 conflicting role in many damage models, which sometimes aggravates the induced damage and sometimes alleviates it.

METHODS

WT and knockout (Par2KO) mice were injected with concanavalin A (ConA) to induce immune-mediated hepatitis or with carbon tetrachloride (CCl₄) to elicit direct hepatic damage. To distinguish the immune component from the liver regenerative response, we conducted bone marrow (BM) replacements of WT and Par2KO mice and repeated the damage models.

RESULTS

ConA injection caused limited damage in Par2KO mice livers, while in the WT mice severe damage followed by leukocyte infiltration was evident. Reciprocal BM replacement of WT and Par2KO showed that WT BM-reconstituted Par2KO mice displayed marked liver damage, while in Par2KO BM-reconstituted WT mice, the tissue was generally protected. In the CCl₄ direct damage model, hepatocytes regenerated in WT mice, whereas Par2KO mice failed to recover. Reciprocal BM replacement did not show significant differences in hepatic regeneration. In Par2KO mice, hepatitis was more apparent, while WT recovered regardless of the BM origin.

CONCLUSIONS

We conclude that Par2 activation in the immune system aggravates hepatitis and that Par2 activation in the damaged tissue promotes liver regeneration. When we incorporate this finding and revisit the literature reports, we reconciled the conflicts surrounding Par2's role in injury, recovery, and inflammation.

Concanavalin A as a promising lectin-based anti-cancer agent: the molecular mechanisms and therapeutic potential

Concanavalin A (ConA), the most studied plant lectin, has been known as a potent anti-neoplastic agent for a long time. Since initial reports on its capacity to kill cancer cells, much attention has been devoted to unveiling the lectin's exact molecular mechanism. It has been revealed that ConA can bind to several receptors on cancerous and normal cells and modulate the related signaling cascades. The most studied host receptor for ConA is MT1-MMP, responsible for most of the lectin's modulations, ranging from activating immune cells to killing tumor cells. In this study, in addition to studying the effect of ConA on signaling and immune cell function, we will focus on the most up-to-date advancements that unraveled the molecular mechanisms by which ConA can induce autophagy and apoptosis in various cancer cell types, where it has been found that P73 and JAK/STAT3 are the leading players. Moreover, we further discuss the main signaling molecules causing liver injury as the most significant side effect of the lectin injection. Altogether, these findings may shed light on the complex signaling pathways controlling the diverse responses created via ConA treatment, thereby modulating these complex networks to create more potent lectin-based cancer therapy.

Comprehensive immune cell analysis of human menstrual-blood-derived stem cells therapy to concanavalin A hepatitis

Autoimmune hepatitis is an autoimmune disease with increasing occurrence worldwide. The most common and convenient mouse model is the concanavalin A (ConA) mouse model. Human menstrual-blood-derived stem cells (MenSCs) have shown great potential as a type of mesenchymal stem cell for treating various diseases. Time-of-flight mass cytometry was performed in phosphate-buffered saline control (NC) group and ConA injection with or without MenSCs treatment groups, and conventional flow cytometry was used for further validation. The serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels and H&E staining depicted that MenSCs treatment could significantly alleviate ConA-induced hepatitis. The t-distributed stochastic neighbor embedding (t-SNE) analysis of nine liver samples displayed favorable cell clustering, and the NC group was significantly different from the other two groups. The proportions of CD69⁺ T cells, NKT cells, and PD-L1⁺ macrophages were notably increased by ConA injection, while MenSCs could decrease ConA-induced macrophage percentage and M1 polarization in the liver tissue. The analysis of proinflammatory factors carried out by cytometric bead array demonstrated that tumor necrosis factor alpha (TNF-α), interleukin (IL)-17A, IL-12p70, IL-6, IL-2, IL-1b, and interferon gamma (IFN-γ) were upregulated after ConA injection and then rapidly decreased at 12 h. MenSCs also played an important role in downregulating these cytokines. Here, we described the comprehensive changes in leukocytes in the liver tissue of ConA-induced hepatitis at 12 h after ConA injection and found that MenSCs rescued ConA-induced hepatitis mostly by inhibiting macrophages and M1 polarization in mouse liver.

Berbamine and thymoquinone exert protective effects against immune-mediated liver injury via NF-κB dependent pathway

Background

Immune-mediated hepatitis is a severe impendence to human health, and no effective treatment is currently available. Therefore, new, safe, low-cost therapies are desperately required. Berbamine (BE), a natural substance obtained primarily from Berberis vulgaris L, is a traditional herbal medicine with several bioactivities, such as antimicrobial and anticancer activities. Thymoquinone (TQ), a phytochemical molecule derived from the Nigella sativa plant's black cumin seeds, has attracted interest owing to itsanti-inflammatory, antioxidant, and anticancer properties.

Aim

This current study's aims was to examine the protective impacts of BE and TQ in Concanavalin A (ConA)- induced acute liver injury and the action's underlying mechanism.

Methods

sixty mice of both sexes were used and divided into four groups (each group with six mice) as follows: Group I obtained distilled water (negative control group). Group II received distilled water with a single dose of 0.1 ml ConA (20 mg/kg) on day 4 by retro-orbital route (model group). Groups III and IV received BE (30 mg/kg/day) and TQ (25 mg/kg/day), respectively, by oral gavage for four successive days, with a single dose of ConA (20 mg/kg) on day 4, then all animals were sacrificed after 8 h and prepared for liver and blood collection.

Results

ConA administration increased the ALT, AST, TNF-α, INFγ, and NF-κB significantly (p < 0.001) in the model group. Both BE and TQ could reduce these parameters significantly (p < 0.001) in groups III and IV, respectively, compared to the model group.

Conclusion

Both BE and TQ prominently attenuated ConA immune-mediated liver injury. These findings give a remarkable insight into developing a new therapeutic agent for treating hepatitis and other autoimmune diseases.

Human Umbilical Cord Blood Mononuclear Cells Ameliorate CCl4-Induced Acute Liver Injury in Mice via Inhibiting Inflammatory Responses and Upregulating Peripheral Interleukin-22

Background: Human umbilical cord blood mononuclear cells (hUCBMNCs) show therapeutic effects on many inflammatory diseases. The deterioration of acute liver injury is attributed to excessive inflammatory responses triggered by damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs). Whether hUCBMNCs treatment is a promising strategy for acute liver injury/failure needs to be investigated.

Methods: Liver injury mice induced by PAMPs, DAMPs, or DAMPs plus PAMPs were developed. DAMPs included CCl4 (carbon tetrachloride), APAP (acetaminophen), and ConA (Concanavalin A). PAMPs included Klebsiella pneumoniae (K.P.) and Salmonella typhimurium (S. Typhimurium). DAMP plus PAMP-induced liver injury was developed by sequential CCl4 and K.P. administration. hUCBMNCs were injected intravenously.

Results: hUCBMNCs significantly prolonged mice survival time in DAMP plus PAMP-induced liver failure but had no benefit in bacteria-infected mice. hUCBMNCs significantly alleviated hepatic necrosis post CCl4/ConA insult. In CCl4-induced acute liver injury, peripheral levels of interleukin (IL)-22 were upregulated and liver regeneration was enhanced after treating with hUCBMNCs at 48h. The levels of p62 and LC3B-II, autophagy markers, were also upregulated in the hUCBMNC-treated group.

Conclusion: hUCBMNCs as a kind of cell therapeutic strategy could attenuate acute liver injury in mice, which is executed by enhancing autophagy and regeneration in the liver via inhibiting inflammatory responses and upregulating peripheral IL-22.

Cucurbitacin E glucoside alleviates concanavalin A-induced hepatitis through enhancing SIRT1/Nrf2/HO-1 and inhibiting NF-ĸB/NLRP3 signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Cucurbitacins are highly oxygenated tetracyclic triterpenoids, that represent the major metabolites reported from C. colocynthis (L.) Schrad.. Cucurbitacin E glucoside (CuE) is a tetracyclic triterpene glycoside separated from Cucurbitaceae plants. CuE has potent anti-inflammatory, immunomodulatory, and anti-tumor properties.

AIM OF THE STUDY

The current study aimed at examining the hepatoprotective effect of CuE against concanavalin A (Con A)-produced hepatitis.

MATERIALS AND METHODS

Mice were intravenously administered Con A (15 mg/kg) to induce AIH. CuE was orally administered at two different doses for five days preceding Con A injection.

RESULTS

The results revealed that CuE pretreatment markedly attenuated the serum indices of hepatotoxicity and the severity of hepatic lesions. CuE depressed Con A-provoked increment in CD4⁺ T-cells in hepatic tissue. The antioxidant activity of CuE was evident through its ability to decrease markers of Con A-induced oxidative stress (malondialdehyde, 4-hydroxyenonanal, and protein carbonyl) and intensified the antioxidants in the hepatic tissue (SOD, GSH, and TAC). CuE increased mRNA expression of SIRT1 and Nrf2 as well as its binding capacity. Subsequently, CuE augmented mRNA expression of Nrf2 targeted genes as NQO1, GCL, and HO-1 and recovered its normal level. CuE inhibited the activation of NF-κB/downstream pro-inflammatory mediators signaling. Furthermore, CuE attenuated the mRNA expression of NLRP3 and its associated genes.

CONCLUSION

Collectively, these results demonstrated the remarkable hepatoprotective potential of CuE towards Con A-induced AIH which was mediated via suppression of oxidative stress, enhancing SIRT1/Nrf2/HO-1, and prohibition of the NF-κB/NLRP3 signaling. CuE could be a candidate for hepatitis patients.

Hepatoprotective Polysaccharides from Geranium wilfordii: Purification, Structural Characterization, and Their Mechanism

Traditional Chinese Medicine is generally used as a decoction to guard health. Many active ingredients in the decoction are chemical ingredients that are not usually paid attention to in phytochemical research, such as polysaccharides, etc. Based on research interest in Chinese herbal decoction, crude polysaccharides from G. wilfordii (GCP) were purified to obtain two relatively homogeneous polysaccharides, a neutral polysaccharide (GNP), and an acid polysaccharide (GAP) by various chromatographic separation methods, which were initially characterized by GC-MS, NMR, IR, and methylation analysis. Studies on the hepatoprotective activity of GCP in vivo showed that GCP might be a potential agent for the prevention and treatment of acute liver injury by inhibiting the secretion levels of ALT, AST, IL-6, IL-1β, TNF-α, and MDA expression levels, increasing SOD, and the GSH-Px activity value. Further, in vitro assays, GNP and GAP, decrease the inflammatory response by inhibiting the secretion of IL-6 and TNF-α, involved in the STAT1/T-bet signaling pathway.

Targeting Glutamine Metabolism Ameliorates Autoimmune Hepatitis via Inhibiting T Cell Activation and Differentiation

BACKGROUND

Autoimmune hepatitis (AIH) is mediated by a cascade of T cell-mediated events directed at liver cells and persistent inflammation within the liver can eventually result in liver cirrhosis. Targeting glutamine metabolism has an impact on T cell activation and differentiation. However, the effect of glutamine metabolism blocking upon AIH remains unknown. We use glutaminase antagonist 6-diazo-5-oxo-L-norleucine (DON) for in vitro assays and its prodrug 2-(2-amino-4-methylpentanamido)-DON (JHU083) for in vivo assays to investigate the potential therapeutic effect and molecular mechanism of glutamine metabolism blocking in an AIH murine model.

METHODS

AIH mice were treated with JHU083 or vehicle before concanavalin A (ConA) administration, and disease severity was examined. Then activation and differentiation [including Th1/Th17 cells and cytotoxic T lymphocytes (CTL)] of T cells from Vehicle-WT, JHU083-AIH and Vehicle-AIH mice were tested. Furthermore, in vitro T cell activation and differentiation were measured using separated splenocytes stimulated with ConA with or without DON. The activation and differentiation of T cells were tested using flow cytometry, qRT-PCR and ELISA. Phosphorylation level of mammalian target of rapamycin (mTOR) and 70 kDa ribosomal protein S6 kinase (P70S6K) were examined by western blotting.

RESULTS

JHU083 and DON significantly suppressed the activation of T cells and inhibited the differentiation of Th1/Th17 cells and CTL in vivo and in vitro. Besides, we demonstrated that glutamine metabolism blocking inhibited T cells activation and differentiation through decreasing the mRNA expression of amino acid transporter solute carrier family 7 member 5 (SLC7A5) and mitigating the activation of mTOR signaling.

CONCLUSIONS

We proved that targeting glutamine metabolism represents a potential new treatment strategy for patients with AIH and other T cell-mediated disease. Mechanistically, we demonstrated that glutamine metabolism blocking inhibits T cells activation and suppresses the differentiation of Th1/Th17 cells and CTL.

Pharmacokinetic/Pharmacodynamic Evaluation of a New Purine-2,6-Dione Derivative in Rodents with Experimental Autoimmune Diseases

Current treatment strategies of autoimmune diseases (ADs) display a limited efficacy and cause numerous adverse effects. Phosphodiesterase (PDE)4 and PDE7 inhibitors have been studied recently as a potential treatment of a variety of ADs. In this study, a PK/PD disease progression modeling approach was employed to evaluate effects of a new theophylline derivative, compound 34, being a strong PDE4 and PDE7 inhibitor. Activity of the studied compound against PDE1 and PDE3 in vitro was investigated. Animal models of multiple sclerosis (MS), rheumatoid arthritis (RA), and autoimmune hepatitis were utilized to assess the efficacy of this compound, and its pharmacokinetics was investigated in mice and rats. A new PK/PD disease progression model of compound 34 was developed that satisfactorily predicted the clinical score-time courses in mice with experimental encephalomyelitis that is an animal model of MS. Compound 34 displayed a high efficacy in all three animal models of ADs. Simultaneous inhibition of PDE types located in immune cells may constitute an alternative treatment strategy of ADs. The PK/PD encephalomyelitis and arthritis progression models presented in this study may be used in future preclinical research, and, upon modifications, may enable translation of the results of preclinical investigations into the clinical settings.

Pharmacokinetic/Pharmacodynamic Assessment of Selective Phosphodiesterase Inhibitors in a Mouse Model of Autoimmune Hepatitis

Autoimmune hepatitis (AIH) is a life-threatening disorder currently treated with nonspecific immunosuppressive drugs. It is postulated that phosphodiesterase (PDE) inhibitors, as agents exerting anti-inflammatory and immunomodulatory activities, may constitute a possible treatment of autoimmune disorders. This study develops a pharmacokinetic/pharmacodynamic (PK/PD) model to assess the effects of PDE-selective inhibitors, namely, cilostazol (PDE3), rolipram (PDE4), and BRL-50481 (PDE7), in a mouse model of AIH. The pharmacokinetics of the PDE inhibitors (PDEi) were assessed in male BALB/c mice after intraperitoneal administration. In pharmacodynamic studies, mice received PDEi and AIH was induced in these animals by intravenous injection of concanavalin A (ConA). Serum drug concentrations, tumor necrosis factor α (TNFα), interleukin 17 (IL-17), and aminotransferase activities were quantified. The PK/PD analysis was performed using ADAPT5 software. The PK/PD model assumes inhibition of cAMP hydrolysis in T cells by PDEi, ConA-triggered formation of TNFα and IL-17, suppression of TNFα and IL-17 production by cAMP, and stimulatory effects of TNFα and IL-17 on the hepatic release of aminotransferases. Selective blockage of PDE4 leads to the highest inhibition of cAMP degradation in T cells and amelioration of disease outcomes. However, inhibition of both PDE3 and PDE7 also contribute to this effect. The proposed PK/PD model may be used to assess and predict the activities of novel PDEi and their combinations in ConA-induced hepatitis. A balanced suppression of different types of PDE appears to be a promising treatment option for AIH; however, this hypothesis warrants testing in humans based on translation of the PK/PD model into clinical settings. SIGNIFICANCE STATEMENT: A novel PK/PD model of PDE inhibitor effects in mice with ConA-induced autoimmune hepatitis was developed involving a mechanistic component describing changes in cAMP concentrations in mouse T cells. According to model predictions, inhibition of PDE4 in T cells causes the highest cAMP elevation in T cells, but suppression of PDE3 and PDE7 also contribute to this effect. A balanced inhibition of PDE3, PDE4, and PDE7 appears to be a promising treatment strategy for AIH.

Hepatoprotective Role of 4-Octyl Itaconate in Concanavalin A-Induced Autoimmune Hepatitis

4-Octyl itaconate (OI) is a novel anti-inflammatory metabolite that exerts protective effects in many various disease models. However, its function in autoimmune hepatitis- (AIH-) associated hepatic injury has not been investigated. In this study, we successfully used concanavalin A (Con A) to establish an AIH-associated liver injury model. Furthermore, we investigated the effect of OI in Con A-induced liver injury and found that OI mitigated Con A-induced histopathological damage. OI administration reduced serum levels of alanine transaminase and aspartate transaminase in Con A-treated mice and attenuated the infiltration of macrophages induced by Con A. Moreover, OI effectively inhibited the expression of proinflammatory cytokines including interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ), and IL-1β induced by Con A. Furthermore, OI decreased hepatocyte apoptosis and malondialdehyde levels and increased the reduced glutathione/oxidized glutathione ratio in the Con A-induced liver injury model. In addition, we found that OI inhibited Con A-induced hepatocyte apoptosis in vitro, while Nrf2 deletion eliminated this effect. Furthermore, we administrated the Nrf2 inhibitor ML385 in OI+Con A-treated mice and found that ML385 eliminated the protective effect of OI in vivo. In addition, OI inhibited Con A-induced activation of nuclear factor-kappa B (NF-𝜅B) and the expression of proinflammatory cytokines in macrophages. Therefore, OI protected mice from Con A-induced liver damage and may be associated with Nrf2 activation and NF-𝜅B inhibition. Finally, our study revealed that OI inhibited TNF-α, or supernatants from Con A-treated RAW264.7 cells induced hepatocyte apoptosis. In conclusion, our study indicated that OI alleviated Con A-induced hepatic damage by reducing inflammatory response, oxidative stress, and apoptosis.

Concanavalin A-induced autoimmune hepatitis model in mice: Mechanisms and future outlook

The concanavalin A (Con A)-induced liver injury mouse model is a typical animal model focusing on T cell-dependent hepatic damage in the field of autoimmune hepatitis (AIH). However, the underlying mechanism of hepatic dysfunction due to cell activation or signaling pathways triggered by Con A has not been fully clarified. Therefore, the controversy on this model remains in the academic community. In this article, we first summarized the merit and demerit of this contentious model from the perspectives of cell dysfunction, microcirculation disturbance, involved signaling pathways, as well as the properties of Con A. Then, we summed up the scientific implications of the model in elucidating the pathogenesis of AIH, and the shortcomings of this model were also summarized to elucidate the pathogenesis and application prospect of this classical liver injury mouse model in the study of AIH.

Corilagin Ameliorates Con A-Induced Hepatic Injury by Restricting M1 Macrophage Polarization

Immune-mediated hepatic injury plays a key role in the initiation and pathogenesis of diverse liver diseases. However, treatment choice for immune-mediated hepatic injury remains limited. Corilagin, a natural ellagitannin extracted from various traditional Chinese medicines, has been demonstrated to exhibit multiple pharmacological activities, such as anti-inflammatory, anti-tumor, and hepatoprotective properties. The present study aimed to investigate the effects of corilagin on immune-mediated hepatic injury using a murine model of concanavalin A (Con A)-induced hepatitis, which is well-characterized to study acute immune-mediated hepatitis. Herein, mice were administered corilagin (25 mg/kg) intraperitoneally twice at 12 h intervals, and 1 h later, the mice were challenged with Con A (20 mg/kg body weight); serum and liver samples were collected after 12 h. The results showed that corilagin significantly increased the survival of mice and reduced serum alanine transaminase (ALT) and aspartate aminotransferase (AST) levels. In addition, corilagin markedly improved histopathological damage, hepatocyte apoptosis, and oxidative stress in the liver. The activation of M1 macrophages in the hepatic mononuclear cells was also significantly reduced compared with that in the control group. The expression of M1 macrophage-associated proinflammatory cytokines and genes, including interleukin (IL)-6, IL-12, and inducible nitric oxide synthase (iNOS), was also decreased after corilagin treatment. Finally, the results demonstrated that corilagin regulated macrophage polarization by modulating the mitogen-activated protein kinases (MAPK), nuclear factor (NF)-κB, and interferon regulatory factor (IRF) signaling pathways. Thus, the findings indicate that corilagin protects mice from Con A-induced immune-mediated hepatic injury by limiting M1 macrophage activation via the MAPK, NF-κB, and IRF signaling pathways, suggesting corilagin as a possible treatment choice for immune-mediated hepatic injury.

Liposomal Formulations Enhance the Anti-Inflammatory Effect of Eicosapentaenoic Acid in HL60 Cells

Dietary omega 3 polyunsaturated fatty acids (PUFAs), including docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), have been reported to be beneficial for cardiovascular diseases and cancer. Such diseases share a common pathophysiological feature of inflammation responses, such as unbalanced oxidative stress and increased cytokine release. PUFAs show anti-inflammatory effects, and thus, they are potential therapeutics to treat inflammatory disorders. Here, we proposed a novel liposomal formulation of EPA (EPA-liposomes), and the liposome was PEGylated to increase their stability. In the study, we measured the physicochemical characteristics of EPA-liposomes and their anti-inflammatory effects in neutrophil-like cells (HL 60 cells). The results showed that EPA-liposomes dramatically decreased the production of NO, ROS, and cytokines compared to EPA alone, and the molecular mechanism is associated with biosynthesis of RvE1 from EPA, and RvE1 binds to GPCRs to mediate the anti-inflammatory effects.

Functional characterization of a novel tumor necrosis factor gene (TNF-New) in rock bream (Oplegnathus fasciatus)

The novel tumor necrosis factor (TNF-New or TNFN) gene has been identified only in teleost such as zebrafish, medaka (Oryzias latipes), fugu (Takifugu rubripes), and rainbow trout (Oncorhynchus mykiss). In this study, a putative TNFN gene in rock bream (named RB-TNFN) was cloned and its functional expression in the immune system was analyzed. Although it was previously reported to share a high degree of homology with mammalian lymphotoxin (LT)-β, in silico analysis revealed that RB-TNFN differed slightly from mammalian LT-β in its genomic structure, phylogenetic relationship, and predicted protein tertiary structure, whereas the genomic location of TNFN (immediately behind TNF-α) was the same as that of LT-β. In healthy rock bream, RB-TNFN gene expression was the highest in the liver and the lowest in the head kidney. In vitro, it was significantly upregulated in head kidney cells following polyinosinic:polycytidylic acid, concanavalin A, phytohemagglutinin, or calcium ionophore (CI) stimulation and in spleen cells by lipopolysaccharide (LPS), CI, and rock bream iridovirus (RBIV). In vivo, it was upregulated in the spleen, liver, and gut on day 1 and in the blood on day 3 following LPS injection, and in the blood, head kidney, and liver following RBIV vaccination. Post-RBIV infection, the vaccinated group showed a significantly higher TNFN gene expression in the head kidney and blood than the unvaccinated group. Treatment with recombinant TNFN protein (RB-rTNFN) resulted in significantly upregulated interleukin-1β expression in the head kidney, spleen, blood, liver, and peritoneal cells. It also enhanced IL-8 gene expression in the head kidney, blood, and peritoneal cells, and interferon γ gene expression in the gut and gills on day 1. TNFN and cyclo-oxygenase-2 gene expression was upregulated in peritoneal cells on day 3. Flow cytometry analysis revealed a significant increase in the peritoneal lymphocyte population after the intraperitoneal (i.p.) injection of RB-rTNFN. These results suggest that RB-TNFN mediated innate and adaptive immunity in rock bream.

Berberine and its derivatives represent as the promising therapeutic agents for inflammatory disorders

Berberine, with the skeleton of quaternary ammonium, has been considered as the well-defined natural product in treating multiple diseases, including inflammation, acute and chronic infection, autoimmune diseases, and diabetes. However, due to the low bioavailability and systemic exposure, broad clinical applications of berberine have been largely impeded. Numerous studies have been conducted to further explore the therapeutic capacities of berberine in preclinical and clinical trials. Over the past, berberine and its derivatives have been shown to possess numerous pharmacological activities, as evidenced in intestinal, pulmonary, skin, and bone inflammatory disorders. In the present review, the pharmacological impact of berberine on inflammatory diseases are fully discussed, with indication that berberine and its potential derivatives represent promising natural therapeutic agents with anti-inflammatory properties.

Synthesis and biological evaluation of novel schisanhenol derivatives as potential hepatoprotective agents

Twenty-one new schisanhenol derivatives were synthesized, and their hepatoprotective effects against liver injury induced by concanavalin A (Con A) were evaluated in vitro using an MTT assay. The data indicated that most derivatives exhibited equivalent or better protective activity than the positive control (dimethyl dicarboxylate biphenyl, DDB) under the same conditions. Among them, compound 1b showed the most potent hepatoprotective activity against Con A-induced immunological injury. Mechanistic studies in vitro revealed that 1b inhibited cell apoptosis and inflammatory responses caused by Con A treatment via IL-6/JAK2/STAT3 signaling pathway. Consistently, it also exhibited significant hepatoprotective activity in mice with Con A-induced immunological liver injury. These results clearly indicated that 1b might be a highly potent hepatoprotective agent targeting IL-6/STAT3 signaling pathway.