Critical roles of conventional dendritic cells in autoimmune hepatitis via autophagy regulation

Immune cell traits and causal relationships with cholecystitis: a mendelian randomization analysis

Cholecystitis, characterized by inflammation of the gallbladder, is intricately linked to immune cells and the cytokines they produce. Despite this association, the specific contributions of immune cells to the onset and progression of cholecystitis remain to be fully understood. To delineate this relationship, we utilized the Mendelian randomization (MR) method to scrutinize the causal connections between 731 immune cell phenotypes and cholecystitis. By conducting MR analysis on 731 immune cell markers from public datasets, this study seeks to understand their potential impact on the risk of cholecystitis. It aims to elucidate the interactions between immune phenotypes and the disease, aiming to lay the groundwork for advancing precision medicine and developing effective treatment strategies for cholecystitis. Taking immune cell phenotypes as the exposure factor and cholecystitis as the outcome event, this study used single nucleotide polymorphisms (SNPs) closely associated with both immune cell phenotypes and cholecystitis as genetic instrumental variables. We conducted a two-sample MR analysis on genome-wide association studies (GWAS) data. Our research thoroughly examined 731 immune cell markers, to determine potential causal relationships with susceptibility to cholecystitis. Sensitivity analyses were performed to ensure the robustness of our findings, excluding the potential impacts of heterogeneity and pleiotropy. To avoid reverse causality, we conducted reverse MR analyses with cholecystitis as the exposure factor and immune cell phenotypes as the outcome event. Among the 731 immune phenotypes, our study identified 21 phenotypes with a causal relationship to cholecystitis (P < 0.05). Of these, eight immune phenotypes exhibited a protective effect against cholecystitis (odds ratio (OR) < 1), while the other 13 immune phenotypes were associated with an increased risk of developing cholecystitis (OR > 1). Additionally, employing the false discovery rate (FDR) method at a significance level of 0.2, no significant causal relationship was found between cholecystitis and immune phenotypes. Our research has uncovered a significant causal relationship between immune cell phenotypes and cholecystitis. This discovery not only enhances our understanding of the role of immune cells in the onset and progression of cholecystitis but also establishes a foundation for developing more precise biomarkers and targeted therapeutic strategies. It provides a scientific basis for more effective and personalized treatments in the future. These findings are expected to substantially improve the quality of life for patients with cholecystitis and mitigate the impact of the disease on patients and their families.

Causal Association Between Circulating Inflammatory Proteins and Autoimmune Liver Disease: a Bidirectional Two-Sample Mendelian Randomization Study

Introduction

To investigate whether there is a direct causal relationship between circulating inflammatory proteins and autoimmune liver disease (AILD).

Materials and Methods

We collected genetic data for various AILD from the Genome Wide Association Studies (GWAS) dataset. The latest research provides GWAS data for 91 proteins associated with inflammation. Perform bidirectional two sample Mendelian randomization (MR) analysis using inverse variance weighted (IVW) to determine the causal relationship between inflammatory proteins and AILD, and use Mendelian randomization Egger method (MR Egger), weighted median (WM), and weighted mode as supplementary evaluations. In addition, we conducted sensitivity analysis.

Results

Positive MR analysis showed that CDCP1 (OR=1.363, p=0.0465) and IL-18 (OR=1.416, p=0.0477) were associated with higher including autoimmune hepatitis (AIH) risk. Higher CXCL11 (OR=1.574, p=9.23×10-5) were associated with an increased risk of primary biliary cholangitis (PBC). Lower levels of three inflammatory proteins were associated with increased risk of PBC. TNFSF12 (OR=1.827, p=0.0001, p_adj_fdr=0.0063), CD6 isoform (OR=1.126, p=0.0389), CCL20 (OR=1.880, p=0.0395) are associated with increased risk of primary sclerosing cholangitis (PSC). Reverse MR imaging showed that PBC may promote the expression levels of CCL4 (OR=1.023, p=0.0201) and OSM (OR=1.022, p=0.0236). PSC may promote the expression of five inflammatory proteins. Sensitivity analysis further excluded the effects of heterogeneity and horizontal pleiotropy.

Conclusion

This study indicates a potential association between circulating inflammatory proteins and AILD, which may become a new diagnostic indicator or drug target for clinical application in the prevention and treatment of AILD. However, further investigation is needed.

Sulforaphane regulation autophagy-mediated pyroptosis in autoimmune hepatitis via AMPK/mTOR pathway

Autoimmune hepatitis (AIH) is a liver disease marked by inflammation of unknown origin. If untreated, it can progress to cirrhosis or liver failure, posing a significant health risk. Currently, effective drug therapies are lacking in clinical practice. Sulforaphane (SFN), a natural anti-inflammatory and antioxidant compound found in various cruciferous vegetables, alleviate pyroptosis and improve impaired autophagic flux, both of which contribute to AIH progression. However, whether SFN modulates autophagic flux and pyroptosis in S100-induced EAH through the AMPK/mTOR pathway remains unclear. Therefore, this study aims to investigate whether SFN can regulate AIH and elucidate its potential mechanisms of action. In this study, experimental AIH (EAH) was induced in male C57BL/6 J mice through intraperitoneal (i.p.) injection of S100. SFN was administered intraperitoneally every other day. After 28 days, the mice were euthanized, and their livers and serum were collected for histological and biochemical analyses. AML12 cells were used for the in vitro studies. The results showed that SFN mitigated pyroptosis by inhibiting the NLRP3 inflammasome and improving autophagic flux, which alleviates S100-induced EAH. Conversely, the autophagy inhibitor 3-MA negated the protective effects of SFN against inflammasome-mediated pyroptosis. Furthermore, SFN activated the AMPK/mTOR signaling pathway, offering protection against S100-induced EAH. Selective inhibition of AMPK suppressed the improvement in autophagic flux and protected against SFN-induced pyroptosis. Overall, SFN significantly ameliorates S100-induced EAH by enhancing autophagic flux and mitigating pyroptosis through activation of the AMPK/mTOR signaling pathway.

Unveiling the interplay between hepatocyte SATB1 and innate immunity in autoimmune hepatitis

BACKGROUND

Investigating the function of SATB1 in hepatocytes is essential for developing therapeutic strategies for autoimmune hepatitis (AIH). Although SATB1 has been extensively studied in immune cells, its specific activity in hepatocytes within the context of AIH remains unclear.

METHODS

SATB1 expression in AIH hepatocytes was assessed by qRT-PCR, Western blotting, flow cytometry, and immunohistochemistry. In vivo modulation used RNA interference viruses and overexpression plasmids. SATB1's proinflammatory effects were analyzed with protein microarray, immunohistochemistry, and flow cytometry. Chemotactic effects on RAW264.7 macrophages were tested in vitro, with mechanisms explored by dual-luciferase assays and CUT&RUN qPCR. Liver injury was evaluated by histopathology and serum biochemistry.

RESULTS

SATB1 was significantly upregulated in hepatocytes of AIH patients and models, showing a stronger increase in hepatocytes than in CD45+ cells, and positively correlated with liver injury severity. In vivo RNAi-mediated SATB1 inhibition reduced liver inflammation, while SATB1 overexpression aggravated AIH progression. Both interference and overexpression experiments confirmed that SATB1 promotes liver injury by facilitating the infiltration of proinflammatory (Ly6Chigh) macrophage. In vitro, supernatant from SATB1-overexpressing hepatocytes enriched chemokine signaling pathways, leading to increased CCL2 expression and release, which attracted macrophages and drove their proinflammatory polarization. Mechanistically, SATB1 promoted CCL2 transcription by binding to its DNA and recruiting p300/CBP.

CONCLUSIONS

This study reveals that SATB1 is upregulated in hepatocytes in AIH. Elevated SATB1 levels in liver cells contribute to autoimmune hepatitis by increasing CCL2 expression, promoting the recruitment of inflammatory monocyte-derived macrophage, and reshaping the composition of the liver immune microenvironment.

1,25(OH)2D3-treated mouse bone marrow-derived dendritic cells alleviate autoimmune hepatitis in mice by improving TFR/TFH imbalance

OBJECTIVE

Autoimmune hepatitis (AIH) is a chronic progressive autoimmune disease with unclear etiology. As a bioactive metabolite of Vitamin D, 1,25(OH)2D3 can stimulate the production of tolerogenic dendritic cells (DCs) that overexpress programmed cell death ligand 1 (PD-L1). Although these cells have been shown to play a part in autoimmune diseases, their role in AIH remains unclear.

METHODS

This study aimed to investigate the potential effect of 1,25(OH)2D3-modulated DCs (PD-L1high VD3-DCs) in a murine model of experimental autoimmune hepatitis (EAH).

RESULTS

Our results showed that intravenous injection of PD-L1high VD3-DCs significantly attenuated liver injury and EAH severity in mice. In addition, PD-L1high VD3-DC infusion improved the imbalance between splenic regulatory T cells (TFR) and follicular helper T (TFH) cells in EAH mice by increasing the number of TFR cells and restoring TFR/TFH ratio. Also, PD-L1high VD3-DC infusion selectively promoted TFR expansion and inhibited TFH differentiation. Furthermore, PD-L1high VD3-DC infusion increased TGF-β and IL-10 production, inhibited IL-21 secretion, upregulated key TFH transcriptional factors, and reduced the levels of serum immunoglobulins in EAH mice.

CONCLUSIONS

To sum up, PD-L1high VD3-DC infusion could control EAH progression in mice by regulating TFR/TFH imbalance, indicating PD-L1high VD3-DC infusion might be a promising therapeutic approach for AIH treatment.

Berberine sensitizes immune checkpoint blockade therapy in melanoma by NQO1 inhibition and ROS activation

Unprecedented progress in immune checkpoint blockade (ICB) therapy has been made in cancer treatment. However, the response to ICB therapy is limited to a small subset of patients. The development of ICB sensitizers to improve cancer immunotherapy outcomes is urgently needed. Berberine (BBR), a well-known phytochemical compound isolated from many kinds of medicinal plants such as Berberis aristata, Coptis chinensis, and Phellondendron chinense Schneid, has shown the ability to inhibit the proliferation, invasion and metastasis of cancer cells. In this study, we investigated whether BBR can enhance the therapeutic benefit of ICB for melanoma, and explored the underlying mechanisms involved. The results showed that BBR could sensitize ICB to inhibit tumor growth and increased the survival rate of mice. Moreover, BBR stimulated intracellular ROS production partially by inhibiting NQO1 activity, which induced immunogenic cell death (ICD) in melanoma, elevated the levels of damage-associated molecular patterns (DAMPs), and subsequently activated DC cells and CD8 + T cells in vitro and in vivo. In conclusion, BBR is a novel ICD inducer. BBR could enhance the therapeutic benefit of ICB for melanoma. These effects were partially mediated through the inhibition of NQO1 and ROS activation.

Identification and experimental validation of genes associated with programmed cell death in dendritic cells of the thyroid tissue in Hashimoto's thyroiditis

INTRODUCTION

Hashimoto's thyroiditis (HT) is a chronic autoimmune disorder. As antigen-presenting cells, dendritic cells(DCs) play a pivotal role in inducing programmed cell death (PCD) types, contributing to immune disorders. This study aimed to identify genes associated with multiple PCD pathways in dendritic cells within the thyroid tissue of patients with HT.

METHODS

The single-cell RNA-sequencing dataset HRA001684 was obtained from the National Genomics Data Center (NGDC) to calculate the area under the curve (AUC) scores for PCD-related genes. Additionally, mRNA sequencing datasets GSE138198 and HRA001684 were sourced from the Gene Expression Omnibus(GEO) and NGDC, respectively. Differentially expressed genes (DEGs) were identified by comparing normal and HT groups in GSE138198 and HRA001684. The intersection of these DEGs with PCD-related genes led to the identification of 17 PCD-related DEGs(PCDDEGs).

RESULTS

AUC scores revealed that DCs in HT exhibited significantly elevated levels of necroptosis, ferroptosis, pyroptosis, autophagy, and PANoptosis, expressing six key PCDDEGs: TNFAIP3, CYBB, PTPN6, STAT1, TGFB1, and NLRP3. These genes displayed an AUC>0.8 for HT in the GSE29315, GSE138198, and HRA001684 datasets, confirming their diagnostic accuracy. Moreover, their expression was positively correlated with the serum levels of thyroid peroxidase and thyroglobulin antibodies, while the expression of all PCDDEGs was negatively correlated with the abundance of thyroid follicular epithelial cells. qRT-PCR, WB, IHC, and IF experiments further confirmed the differences in PCDDEGs gene and protein levels in HT patients.

DISCUSSION

These findings highlight the crucial role of DCs in mediating PCD within the thyroid tissues of HT patients. The identified PCDDEGs-TNFAIP3, CYBB, PTPN6, STAT1, TGFB1, and NLRP3-may significantly contribute to HT pathogenesis through PCD pathways.

New insight in treating autoimmune diseases by targeting autophagy

Autophagy is a highly conserved biological process in eukaryotes, which degrades cellular misfolded proteins, damaged organelles and invasive pathogens in the lysosome-dependent manner. Autoimmune diseases caused by genetic elements, environments and aberrant immune responses severely impact patients' living quality and even threaten life. Recently, numerous studies have reported autophagy can regulate immune responses, and play an important role in autoimmune diseases. In this review, we summarised the features of autophagy and autophagy-related genes, enumerated some autophagy-related genes involved in autoimmune diseases, and further overviewed how to treat autoimmune diseases through targeting autophagy. Finally, we outlooked the prospect of relieving and curing autoimmune diseases by targeting autophagy pathway.

Metabolic Reprogramming of CD4+ T Cells by Mesenchymal Stem Cell-Derived Extracellular Vesicles Attenuates Autoimmune Hepatitis Through Mitochondrial Protein Transfer

Background

Autoimmune hepatitis (AIH) is a serious liver disease characterized by immune disorders, particularly effector T-cell overactivation. This study aimed to explore the therapeutic effect and underlying mechanism of mesenchymal stem cell-derived extracellular vesicle (MSC-EV) treatment on CD4+ T-cell overactivation and liver injury in AIH.

Methods

The metabolic changes of CD4+ T cells were assayed in human AIH and mouse hepatitis models. The liver protective effect of MSC-EVs was evaluated by transaminase levels, liver histopathology and inflammation. The effect of MSC-EVs on the metabolic state of CD4+ T cells was also explored.

Results

Enhanced glycolysis (eg, ~1.5-fold increase in hexokinase 2 levels) was detected in the CD4+ T cells of AIH patient samples and mouse hepatitis models, whereas the inhibition of glycolysis decreased CD4+ T-cell activation (~1.8-fold decrease in CD69 levels) and AIH liver injury (~6-fold decrease in aminotransferase levels). MSC-EV treatment reduced CD4+ T-cell activation (~1.5-fold decrease in CD69 levels) and cytokine release (~5-fold decrease in IFN-γ levels) by reducing glycolysis (~3-fold decrease) while enhancing mitochondrial oxidative phosphorylation (~2-fold increase in maximal respiration) in such cells. The degree of liver damage in AIH mice was ameliorated after MSC-EV treatment (~5-fold decrease in aminotransferase levels). MSC-EVs carried abundant mitochondrial proteins and might transfer them to metabolically reprogram CD4+ T cells, whereas disrupting mitochondrial transfer impaired the therapeutic potency of MSC-EVs in activated CD4+ T cells.

Conclusion

Disordered glucose metabolism promotes CD4+ T-cell activation and associated inflammatory liver injury in AIH models, which can be reversed by MSC-EV therapy, and this effect is at least partially dependent on EV-mediated mitochondrial protein transfer between cells. This study highlights that MSC-EV therapy may represent a new avenue for treating autoimmune diseases such as AIH.

Conventional type 1 dendritic cells are essential for the development of primary biliary cholangitis

BACKGROUND & AIMS

Primary biliary cholangitis (PBC) is a progressive-cholestatic autoimmune liver disease. Dendritic cells (DC) are professional antigen-presenting cells and their prominent presence around damaged bile ducts of PBC patients are documented. cDC1 is a rare subset of DC known for its cross-presentation abilities and interleukin 12 production. Our aim was to assess the role of cDC1 in the pathogenesis of PBC.

METHODS

We utilized an inducible murine model of PBC and took advantage of the DC reporter mice Zbtb46gfp and the Batf3-/- mice that specifically lack the cDC1 subset. cDC1 cells were sorted from blood of PBC patients and healthy individuals and subjected to Bulk-MARS-seq transcriptome analysis.

RESULTS

Histopathology assessment demonstrated peri-portal inflammation in wild type (WT) mice, whereas only minor abnormalities were observed in Batf3-/- mice. Flow cytometry analysis revealed a two-fold reduction in hepatic CD8/CD4 T cells ratio in Batf3-/- mice, suggesting reduced intrahepatic CD8 T cells expansion. Histological evidence of portal fibrosis was detected only in the WT but not in Batf3-/- mice. This finding was supported by decreased expression levels of pro-fibrotic genes in the livers of Batf3-/- mice. Transcriptome analysis of human cDC1, revealed 78 differentially expressed genes between PBC patients and controls. Genes related to antigen presentation, TNF and IFN signalling and mitochondrial dysfunction were significantly increased in cDC1 isolated from PBC patients.

CONCLUSION

Our data illustrated the contribution the cDC1 subset in the pathogenesis of PBC and provides a novel direction for immune based cell-specific targeted therapeutic approach in PBC.

Deficiency of purinergic P2X4 receptor alleviates experimental autoimmune hepatitis in mice

Purinergic P2X4 receptor (P2X4R) has been shown to have immunomodulatory properties in infection, inflammation, and organ damage including liver regeneration and fibrosis. However, the mechanisms and pathophysiology associated with P2X4R during acute liver injury remain unknown. We used P2X4R-/- mice to explore the role of P2X4R in three different models of acute liver injury caused by concanavalin A (ConA), carbon tetrachloride, and acetaminophen. ConA treatment results in an increased expression of P2X4R in the liver of mice, which was positively correlated with higher levels of aspartate aminotransferase and alanine aminotransferase in the serum. However, P2X4R gene ablation significantly reduced the severity of acute hepatitis in mice caused by ConA, but not by carbon tetrachloride or acetaminophen. The protective benefits against immune-mediated acute hepatitis were achieved via modulating inflammation (Interleukin (IL)-1β, IL-6, IL-17A, interferon-γ, tumor necrosis factor-α), oxidative stress (malondialdehyde, superoxide dismutase, glutathione peroxidase, and catalase), apoptosis markers (Bax, Bcl-2, and Caspase-3), autophagy biomarkers (LC3, Beclin-1, and p62), and nucleotide oligomerization domain-likereceptorprotein 3(NLRP3) inflammasome-activated pyroptosis markers (NLRP3, Gasdermin D, Caspase-1, ASC, IL-1β). Additionally, administration of P2X4R antagonist (5-BDBD) or agonist (cytidine 5'-triphosphate) either improved or worsened ConA-induced autoimmune hepatitis, respectively. This study is the first to reveal that the absence of the P2X4 receptor may mitigate immune-mediated liver damage, potentially by restraining inflammation, oxidation, and programmed cell death mechanisms. And highlight P2X4 receptor is essential for ConA-induced acute hepatitis.

Autoimmune Hepatitis: Pathophysiology

Genome-wide association analyses suggest that HLA genes including HLA-DRB*0301, HLA-DRB*0401, and HLA-B*3501 as well as non-HLA genes including CD28/CTLA4/ICOS and SYNPR increased AIH susceptibility. The destruction of hepatocytes is the result of the imbalance between proinflammatory cells and immunosuppressive cells, especially the imbalance between Tregs and Th17 cells. The microbiome in patients with AIH is decreased in diversity with a specific decline in Bifidobacterium and enrichment in Veillonella and Faecalibacterium. Recent evidence has demonstrated the pathogenic role of E. gallinarum and L.reuteri in inducing autoimmunity in the liver.

Yiqi Jiedu decoction attenuates radiation injury of spermatogenic cells via suppressing IκBα/NF-κB pathway-induced excessive autophagy and apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

The prescription of Yiqi Jiedu decoction (YQJD) originated from the classic Chinese herbal prescriptions of Danggui Buxue Decoction and Wuzi Yanzong Pill. A previous study has shown that 4 Gy irradiation induced the apoptosis of spermatocytes and revealed autophagosomes in cells exposed to radiation. YQJD decoction has the effect of preventing radiation injury.

AIM OF THE STUDY

We used spermatocytes (GC-2spd cell line) to investigate the relationship between autophagy and apoptosis of spermatogenic cells after radiation, and the mechanisms of YQJD decoction.

MATERIALS AND METHODS

Establish an in vitro radiation injury model by irradiating GC-2spd cells with 60Co γ-rays (4 Gy or 8 Gy). Autophagy agonists, autophagy inhibitors and YQJD were used to intervene cells. Cell apoptosis and inflammatory factors were measured. NF-κB localization was observed by immunofluorescence. Autophagy and apoptosis-related proteins and IκBα/NF-κB pathway factors were detected.

RESULTS

Ionizing radiation promoted the growth of spermatogenic autophagosomes. After radiation, NF-κB was translocated to the nucleus, inflammatory factors were secreted, and IκBα/NF-κB pathway was activated, which promoted autophagy and apoptosis. YQJD decoction can inhibit the phosphorylation of IκBα/NF-κB pathway related factors, regulate the expression of Beclin-1 and Bcl-2 proteins, and inhibit the occurrence of autophagy and apoptosis of irradiated spermatocyte.

CONCLUSIONS

The research results indicate that ionizing radiation can activate the IκBα/NF-κB signaling pathway in spermatocytes, promote cell autophagy and apoptosis by regulating the expression of Beclin-1 and Bcl-2 factors. The YQJD decoction inhibits the IκBα/NF-κB signaling pathway so as to regulate Beclin-1 and Bcl-2.

Autoantigen-selected B cells are bystanders in spontaneous T cell-driven experimental autoimmune hepatitis

Autoreactive B cells are considered pathogenic drivers in many autoimmune diseases; however, it is not clear whether autoimmune B cells are invariably pathogenic or whether they can also arise as bystanders of T cell-driven autoimmune pathology. Here, we studied the B cell response in an autoantigen- and CD4+ T cell-driven model of autoimmune hepatitis (AIH), the Alb-iGP_Smarta mouse in which expression of a viral model antigen (GP) in hepatocytes and its recognition by GP-specific CD4+ T cells causes spontaneous AIH-like disease. T cell-driven AIH in Alb-iGP_Smarta mice was marked by autoantibodies and hepatic infiltration of plasma cells and B cells, particularly of isotype-switched memory B cells, indicating antigen-driven selection and activation. Immunosequencing of B cell receptor repertoires confirmed B cell expansion selectively in the liver, which was most likely driven by the hepatic GP model antigen, as indicated by branched networks of connected sequences and elevated levels of IgG antibodies to GP. However, intrahepatic B cells did not produce increased levels of cytokines and their depletion with anti-CD20 antibody did not alter the CD4+ T cell response in Alb-iGP_Smarta mice. Moreover, B cell depletion did not prevent spontaneous liver inflammation and AIH-like disease in Alb-iGP_Smarta mice. In conclusion, selection and isotype-switch of liver-infiltrating B cells was dependent on the presence of CD4+ T cells recognizing liver antigen. However, recognition of hepatic antigen by CD4+ T cells and CD4+ T cell-mediated hepatitis was not dependent on B cells. Thus, autoreactive B cells can be bystanders and need not be drivers of liver inflammation in AIH.

A DNA vaccine (EG95-PT1/2/3-IL2) encoding multi-epitope antigen and IL-2 provokes efficient and long-term immunity to echinococcosis

Echinococcosis is a highly prevalent global zoonosis, and vaccines are required. The commercial vaccine based on a protein-based subunit (EG95), however, is limited by its insufficient cellular immunity, a short protection period, and limited prevention against novel mutant strains. Herein, we applied bioinformatics to develop a DNA vaccine (pEG95-IL2) expressing both multi-epitope-based antigens (EG95-PT1/2/3) and an IL-2 adjuvant to regulate T cell differentiation and memory cell response. EG95-PT1/2/3 was screened with hierarchical structure prediction from the epitope conformation of B cells with high confidence across various species to guarantee immunogenicity. Importantly, cationic arginine-rich lipid nanoparticles (RNP) were utilized as a delivery vehicle to form lipoplexes that had a transfection efficiency of nearly two orders of magnitude greater than that of commercial reagents (Lipofectamine 2000 and polyethyleneimine) with both immune and nonimmune cells (DC2.4 and L929 cells, respectively). RNP/pEG95-IL2 lipoplexes displayed a robust and long-term antigen expression, as well as adjuvant effects during the immunization. Consequently, intramuscular injection of RNP/pEG95-IL2 elicited similar humoral immune responses and significantly greater cellular responses in mice when compared with those of the commercial vaccine. In addition, the inoculation protocol of RNP/pEG95-IL2 with sequential booster further strengthens cellular immunity in comparison with the homologous booster. Those findings provide a promising strategy for improving plasmid vaccine efficacy.

Itaconate attenuates autoimmune hepatitis via PI3K/AKT/mTOR pathway-mediated inhibition of dendritic cell maturation and autophagy

Autoimmune hepatitis (AIH) results from an autoimmune-mediated chronic inflammatory response against liver cells. Defective self-tolerance and dysfunctional dendritic cells (DCs) play a regulatory role in AIH. Itaconate has recently attracted attention in the field of immunometabolism because of its crucial role as an anti-inflammatory metabolite that negatively regulates the inflammatory response. However, the underlying mechanism of itaconate mediation of DCs in AIH remains unclear. In this study, we found that itaconate acts as an anti-inflammatory factor in the liver. Endogenous itaconate levels were significantly increased in mice with S100-induced AIH model and correlated with upregulation of the immune-responsive gene 1 expression. However, the anti-inflammatory response from endogenously itaconate may not represent the effects exogenously-produced itaconate. We investigated the anti-inflammatory response from exogenous itaconate in S100-induced AIH, and our results showed that itaconate treatment attenuated liver histopathological damage, hepatocyte apoptosis, aminotransferase elevation, and IL-6 production in the S100-induced AIH model. In addition, Itaconate decreased glycolysis to suppress the maturation of DCs in the liver and spleen of AIH models, thereby directly regulating differentiation of Th17 and Tregs in vivo. The percentage of Th17 cells among the CD4⁺ population were decreased and Tregs were increased (P < 0.05). Furthermore, Itaconate-induced bone marrow-derived monocytes suppressed CD4⁺cells proliferation. In vitro and in vivo, we found that itaconate suppressed autophagy via activating the PI3K/AKT/mTOR signalling pathway in bone marrow-derived DCs and liver tissues. We further investigated the function of Itaconate on DC-specific mTOR-deficient mice. mTOR-deficient DCs augmented inflammatory reactions in mTOR^DC-/- AIH mice and induced autophagy. MHY1485 (an agonist of mTOR) and itaconate significantly alleviated the inflammatory reaction and autophagy signalling. In conclusion, itaconate ameliorate liver inflammation in S100-induced AIH mice by regulating the PI3K/AKT/mTOR pathway to decrease DCs autophagy and maturation. These results provide insight useful for treating AIH.

Novel potential therapeutic targets of alopecia areata

Alopecia areata (AA) is a non-scarring hair loss disorder caused by autoimmunity. The immune collapse of the hair follicle, where interferon-gamma (IFN-γ) and CD8+ T cells accumulate, is a key factor in AA. However, the exact functional mechanism remains unclear. Therefore, AA treatment has poor efficacy maintenance and high relapse rate after drug withdrawal. Recent studies show that immune-related cells and molecules affect AA. These cells communicate through autocrine and paracrine signals. Various cytokines, chemokines and growth factors mediate this crosstalk. In addition, adipose-derived stem cells (ADSCs), gut microbiota, hair follicle melanocytes, non-coding RNAs and specific regulatory factors have crucial roles in intercellular communication without a clear cause, suggesting potential new targets for AA therapy. This review discusses the latest research on the possible pathogenesis and therapeutic targets of AA.

Myeloid-derived suppressor cells ameliorate liver mitochondrial damage to protect against autoimmune hepatitis by releasing small extracellular vesicles

BACKGROUND

Autoimmune hepatitis (AIH) is an inflammatory liver disease that is associated with impaired self-tolerance. Myeloid-derived supprfessor cells (MDSCs) have been considered to exert counterregulatory effects on AIH. However, the specific mechanism underlying these effects is unclear. Herein, we investigated the efficacy and safety of MDSCs in protecting against AIH and explored the underlying mechanism.

METHODS

Circulating and liver MDSC expression levels in 71 AIH patients and 47 healthy control (HC) individuals were detected by flow cytometry and immunohistochemistry. The adoptive transfer of induced bone marrow-derived MDSCs (BM MDSCs) to AIH mice was used to explore the function of MDSCs. Hepatic injury and mitochondrial damage were evaluated by transaminase levels, histopathology, immunohistochemistry, transmission electron microscopy and western blotting. MDSCs were pretreated with the small extracellular vesicle (sEV) generation inhibitor GW4869 to explore the mechanism. Importantly, sEVs derived from MDSCs and MDSCs-GW4869 were injected into model mice to monitor mitochondrial function and biogenesis.

RESULTS

Circulating and liver MDSCs were expanded in AIH patients and mouse model. Furthermore, the follow-up data of AIH patients showed that immunosuppressive therapy further promoted the expansion of MDSCs. More importantly, the adoptive transfer of BM MDSCs to AIH mice effectively ameliorated liver injury and regulated the imbalance of the immune microenvironment. Additionally, BM MDSCs reduced liver mitochondrial damage and improved mitochondrial biogenesis. Mechanistically, sEVs derived from BM MDSCs showed the same biological effects as cells, and blocking sEV production weakened the function of BM MDSCs. Finally, multiple long-term administrations of BM MDSCs were proven to be safe in general.

CONCLUSION

In conclusion, MDSCs ameliorate liver mitochondrial damage to protect against autoimmune hepatitis by releasing small extracellular vesicles.

Gastrodin ameliorates Concanavalin A-induced acute hepatitis via the IL6/JAK2/STAT3 pathway

AIMS

Gastrodin, the main active ingredient of Gastrodia elata Blume, has been shown to protect against many inflammatory diseases. Our study aimed to investigate the anti-inflammatory role of gastrodin in concanavalin A (ConA)-induced acute hepatitis in mice and to explore its precise mechanism.

METHODS

C57BL/6 mice were administered with gastrodin (50 or 100mg/kg) for 3 days prior to intravenous injection of ConA to induce acute autoimmune hepatitis (AIH). Serum aminotransferases levels and cytokine levels were measured. Liver tissue histology was conducted to assess the degree of liver injury. Splenocytes pretreated with gastrodin were stimulated with ConA to observe splenocyte proliferation.

RESULTS

Gastrodin greatly reduced the level of serum aminotransferases, inflammatory cytokine such as IL-6 and TNF-α and histopathological damage in ConA-induced hepatitis. Besides, gastrodin had an inhibitory effect on liver apoptosis, and autophagy. Furthermore, gastrodin inhibited the proliferation of splenocytes in vitro. The protein expression of p-JAK2 and p-STAT3 was markedly affected by gastrodin pretreatment.

CONCLUSIONS

The present study indicated that gastrodin pretreatment exerted protective effects against ConA-induced acute hepatitis, partly through the inhibition of the IL6/JAK2/STAT3 pathway. Further studies are recommended to determine the potential therapeutic role of gastrodin in acute AIH.

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.

Novel Synthetic Lipopeptides as Potential Mucosal Adjuvants Enhanced SARS-CoV-2 rRBD-Induced Immune Response

As TLR2 agonists, several lipopeptides had been proved to be candidate vaccine adjuvants. In our previous study, lipopeptides mimicking N-terminal structures of the bacterial lipoproteins were also able to promote antigen-specific immune response. However, the structure-activity relationship of lipopeptides as TLR2 agonists is still unclear. Here, 23 synthetic lipopeptides with the same lipid moiety but different peptide sequences were synthesized, and their TLR2 activities in vitro and mucosal adjuvant effects to OVA were evaluated. LP1-14, LP1-30, LP1-34 and LP2-2 exhibited significantly lower cytotoxicity and stronger TLR2 activity compared with Pam₂CSK₄, the latter being one of the most potent TLR2 agonists. LP1-34 and LP2-2 assisted OVA to induce more profound specific IgG in sera or sIgA in BALF than Pam₂CSK₄. Furthermore, the possibility of LP1-34, LP2-2 and Pam₂CSK₄ as the mucosal adjuvant for the SARS-CoV-2 recombinant RBD (rRBD) was investigated. Intranasally immunized with rRBD plus either the novel lipopeptide or Pam₂CSK₄ significantly increased the levels of specific serum and respiratory mucosal IgG and IgA, while rRBD alone failed to induce specific immune response due to its low immunogenicity. The novel lipopeptides, especially LP2-2, significantly increased levels of rRBD-induced SARS-CoV-2 neutralizing antibody in sera, BALF and nasal wash. Finally, Support vector machine (SVM) results suggested that charged residues in lipopeptides might be beneficial to the agonist activity, while lipophilic residues might adversely affect the agonistic activity. Figuring out the relationship between peptide sequence in the lipopeptide and its TLR2 activity may lay the foundation for the rational design of novel lipopeptide adjuvant for COVID-19 vaccine.

Magnesium Isoglycyrrhizinate Ameliorates Concanavalin A-Induced Liver Injury by Inhibiting Autophagy

Background and Aims: Acute liver failure (ALF) is a type of liver injury that is caused by multiple factors and leads to severe liver dysfunction; however, current treatments for ALF are insufficient. Magnesium isoglycyrrhizinate (MgIG), a novel glycyrrhizin extracted from the traditional Chinese medicine licorice, has a significant protective effect against concanavalin A (ConA)-induced liver injury, but its underlying therapeutic mechanism is unclear. Hence, this study aims to explore the potential therapeutic mechanism of MgIG against ConA-induced immune liver injury. Methods: ConA (20 mg/kg, i. v.) was administered for 12 h to construct an immune liver injury model, and the treatment group was given MgIG (30 mg/kg, i. p.) injection 1 h in advance. Lethality, liver injury, cytokine levels, and hepatocyte death were evaluated. The level of autophagy was evaluated by electron microscopy, RT-PCR and western blotting, and hepatocyte death was assessed in vitro by flow cytometry. Results: MgIG significantly increased the survival rate of mice and ameliorated severe liver injury mediated by ConA. The decrease in the number of autophagosomes, downregulation of LC3b expression and upregulation of p62 expression indicated that MgIG significantly inhibited ConA-induced autophagy in the liver. Reactivation of autophagy by rapamycin (RAPA) reversed the protective effect of MgIG against ConA-induced liver injury. Compared with MgIG treatment, activation of autophagy by RAPA also promoted the expression of liver inflammation markers (IL-1β, IL-6, TNF-α, CXCL-1, CXCL-2, CXCL-10, etc.) and hepatocyte death. In vitro experiments also showed that MgIG reduced ConA-induced hepatocyte death but did not decrease hepatocyte apoptosis by inhibiting autophagy. Conclusion: MgIG significantly ameliorated ConA-induced immune liver injury in mice by inhibiting autophagy. This study provides theoretical support for the ability of MgIG to protect against liver injury in clinical practice.

Patients with treated autoimmune hepatitis and persistent suppression of plasmacytoid dendritic cells: A different point of view

Objectives: Plasmacytoid dendritic cells (pDCs) have been shown to have a role in autoimmune diseases, but their role in Autoimmune Hepatitis (AIH) is not completely clear. In the present study, we assessed the frequency of pDCs in peripheral blood of AIH patients under long-term standard immunosuppressive therapy. Methods: This cross-sectional analysis enrolled 27 AIH patients and 27 healthy controls. We analyzed and compared their proportion of pDCs, CD4⁺, CD8⁺, γδ T cells, CD25⁺ regulatory T (Treg) cells, FoxP3⁺, Foxp3⁺CD39⁺ Treg cells, total B (CD19⁺) cells, and plasma cells (CD38⁺) in peripheral blood using flow cytometry immunophenotyping. Results: AIH patients had a lower percentage of pDCs (median frequencies of 0.2% vs. 0.4%; p = .002) and higher expression of CD8 T cells (32.5% vs 28.6%; p = 0.008) in peripheral blood, when compared to healthy controls. We did not find statistically significant differences between the groups regarding the other cell subtypes.Conclusion: Our data suggest a persistent suppression of pDCs in AIH patients, along with increased CD8 T cell activity, years after AIH diagnosis and despite of good clinical response to treatment, thus pointing to a role of pDCs in the AIH pathogenesis.

Long Noncoding RNA and Circular RNA Expression Profiles of Monocyte-Derived Dendritic Cells in Autoimmune Hepatitis

Autoimmune hepatitis (AIH) is a chronic liver disease caused by disruption of liver immune homeostasis. The effect of dendritic cells (DCs) on the pathogenesis of AIH is not fully understood. Long noncoding RNAs (lncRNAs), circular RNAs (circRNAs), and microRNAs (miRNAs) have been shown to play critical roles in the regulation of cell function. In this study, we analyzed the immunophenotypic characteristics of DCs in the peripheral blood. The percentage of mature DCs was higher in AIH patients than in healthy controls (HCs), and the proportion of mature DCs decreased after treatment. We isolated monocyte-derived DCs (moDCs) from the peripheral blood, obtained whole RNA-sequencing (RNA-seq) data for the moDCs from the two groups, and identified differentially expressed (DE) lncRNAs, circRNAs, miRNAs and mRNAs. In addition, we performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses for the DE mRNAs and constructed competing endogenous RNA (ceRNA) networks. ENST00000543334, hsa_circ_0000279, and hsa_circ_0005076 were selected and validated by RT-qPCR. These results provide a possible molecular mechanism of DCs in the pathogenesis of AIH and identify some potential therapeutic targets.

Extracellular IL-37 promotes osteogenic and odontogenic differentiation of human dental pulp stem cells via autophagy

The osteogenic and odontogenic differentiation of dental pulp stem cells (DPSCs) contribute to restoration and regeneration of dental tissue. Previous study indicated that interleukin-37 (IL-37) was an anti-inflammatory factor that affected other pro-inflammatory signals. The aim of this study was to explore the effects of IL-37 on the differentiation of DPSCs. DPSCs were cultured in growth medium with different concentrations of IL-37. We selected the optimal concentration for the following experiments by alkaline phosphatase (ALP) activity analysis, quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and Western blot. Cell counting kit assay (CCK-8) and 5-Ethynyl-2'-Deoxyuridine (EdU) assay were conducted to assess the effects of IL-37 on the proliferation of DPSCs. ALP activity assay and staining, alizarin red S (ARS) staining, qRT-PCR, Western blot as well as immunofluorescence staining were conducted to assess differentiation ability of DPSCs. Western blot, immunofluorescence staining and transmission electron microscopy (TEM) were utilized to examine cell autophagy. Results showed that IL-37 enhanced the osteogenic and odontogenic differentiation ability of DPSCs with no significant influence on the proliferation of DPSCs. Autophagy in DPSCs was activated by IL-37. Activation of autophagy enhanced osteogenesis and odontogenesis of DPSCs, whereas inhibition of autophagy suppressed DPSCs osteogenic and odontogenic differentiation. In conclusion, IL-37 increased osteogenic and odontogenic differentiation via autophagy.

Glucose Metabolism Reprogramming of Regulatory T Cells in Concanavalin A-Induced Hepatitis

Autoimmune hepatitis (AIH) is an inflammatory liver disease caused by a dysregulated immune response. Although the pathogenesis of AIH remains unclear, impaired regulatory T cells (Tregs) have been considered a driver of AIH development. Unlike autoreactive T cells, Tregs mainly utilize oxidative phosphorylation (OXPHOS) as their energy supply. Elevated glycolysis has been reported to limit the suppressive functions of Tregs. However, whether glucose metabolism reprogramming in Tregs is involved in AIH etiology remains unknown. The aim of this study was to examine alternations in Treg numbers and functions in AIH patients and concanavalin A (Con A)-induced hepatitis, while exploring associations between impaired Tregs and glucose metabolism. The frequency of Tregs was decreased in the peripheral blood but increased in liver biopsies of AIH patients. Moreover, immunosuppressive therapy rescued circulating Tregs in AIH. In Con A-induced immune hepatitis, enhanced intrahepatic Treg accumulation was observed over time, accompanied by reduced splenic Treg numbers. To investigate whether functional impairment of Tregs occurs in AIH, Tregs were isolated from experimental AIH (EAH) model mice and normal controls and the former displayed downregulated mRNA levels of FOXP3, CTLA4, CD103, TIGIT, CD39, and CD73. EAH model-derived Tregs also produced fewer anti-inflammatory mediators (TGF-β and IL-35) than control Tregs. Moreover, enhanced glycolysis and reduced OXPHOS were found in Tregs from EAH model mice, as reflected by elevated levels of key glycolytic enzymes (HK2, PK-M2, and LDH-A) and a decreased ATP concentration. This study revealed a decreased peripheral Treg frequency and abnormal intrahepatic Treg infiltration in AIH. It is first reported that glucose metabolism reprogramming is associated with decreases and functional impairments in the Treg population, promoting AIH development. Targeting glucose metabolism may provide novel insights for the treatment of AIH.

Immunomodulatory Role and Therapeutic Potential of Non-Coding RNAs Mediated by Dendritic Cells in Autoimmune and Immune Tolerance-Related Diseases

Dendritic cells (DCs) are professional antigen-presenting cells that act as a bridge between innate immunity and adaptive immunity. After activation, DCs differentiate into subtypes with different functions, at which point they upregulate co-stimulatory molecules and produce various cytokines and chemokines. Activated DCs also process antigens for presentation to T cells and regulate the differentiation and function of T cells to modulate the immune state of the body. Non-coding RNAs, RNA transcripts that are unable to encode proteins, not only participate in the pathological mechanisms of autoimmune-related diseases but also regulate the function of immune cells in these diseases. Accumulating evidence suggests that dysregulation of non-coding RNAs contributes to DC differentiation, functions, and so on, consequently producing effects in various autoimmune diseases. In this review, we summarize the main non-coding RNAs (miRNAs, lncRNAs, circRNAs) that regulate DCs in pathological mechanisms and have tremendous potential to give rise to novel therapeutic targets and strategies for multiple autoimmune diseases and immune tolerance-related diseases.

Autophagy in liver diseases

Autophagy is the liver cell energy recycling system regulating a variety of homeostatic mechanisms. Damaged organelles, lipids and proteins are degraded in the lysosomes and their elements are re-used by the cell. Investigations on autophagy have led to the award of two Nobel Prizes and a health of important reports. In this review we describe the fundamental functions of autophagy in the liver including new data on the regulation of autophagy. Moreover we emphasize the fact that autophagy acts like a two edge sword in many occasions with the most prominent paradigm being its involvement in the initiation and progress of hepatocellular carcinoma. We also focused to the implication of autophagy and its specialized forms of lipophagy and mitophagy in the pathogenesis of various liver diseases. We analyzed autophagy not only in well studied diseases, like alcoholic and nonalcoholic fatty liver and liver fibrosis but also in viral hepatitis, biliary diseases, autoimmune hepatitis and rare diseases including inherited metabolic diseases and also acetaminophene hepatotoxicity. We also stressed the different consequences that activation or impairment of autophagy may have in hepatocytes as opposed to Kupffer cells, sinusoidal endothelial cells or hepatic stellate cells. Finally, we analyzed the limited clinical data compared to the extensive experimental evidence and the possible future therapeutic interventions based on autophagy manipulation.

Autophagy regulation is an effective strategy to improve the prognosis of chemically induced acute liver injury based on experimental studies

Acute liver injury (ALI) induced by chemicals in current experimental studies is characterized by inflammation, oxidative stress and necrosis, which can greatly influence the long-term outcome and lead to liver failure. In liver cells, different autophagy forms envelop cytoplasm components, including proteins, endoplasmic reticulum (ER), mitochondria and lipids, and they effectively participate in breaking down the cargo enclosed inside lysosomes to replenish cellular energy and contents. In general, autophagy serves as a cell survival mechanism in stressful microenvironments, but it also serves as a destructive mechanism that results in cell death in vitro and in vivo. In experimental animals, multiple chemicals are used to mimic ALI in patients to clarify the potential pathological mechanisms and develop effective strategies in the clinic. In this review, we summarize related publications about autophagy modulation to attenuate chemically induced ALI in vitro and in vivo. We also analysed the underlying mechanisms of autophagy regulators and genetic modifications to clarify how to control autophagy to protect against chemically induced ALI in animal models. We anticipate that selectively controlling the dual effects of hepatic autophagy will help to protect against ALI in various animals, but the detailed mechanisms and effects should be determined further in future studies. In this way, we are more confident that modulating autophagy in liver regeneration can improve the prognosis of ALI.