BACKGROUND: G protein-coupled receptor kinase 2 (GRK2) could participate in the regulation of diverse cells via interacting with non-G-protein-coupled receptors. In the present work, we explored how paroxetine, a GRK2 inhibitor, modulates the differentiation and activation of immune cells in rheumatoid arthritis (RA). METHODS: The blood samples of healthy individuals and RA patients were collected between July 2021 and March 2022 from the First Affiliated Hospital of Anhui Medical University. C57BL/6 mice were used to induce the collagen-induced arthritis (CIA) model. Flow cytometry analysis was used to characterize the differentiation and function of dendritic cells (DCs)/T cells. Co-immunoprecipitation was used to explore the specific molecular mechanism. RESULTS: In patients with RA, high expression of GRK2 in peripheral blood lymphocytes, accompanied by the increases of phosphatidylinositol 3 kinase (PI3K), protein kinase B (AKT), and mammalian target of rapamycin (mTOR). In animal model, a decrease in regulatory T cells (T regs ), an increase in the cluster of differentiation 8 positive (CD8 + ) T cells, and maturation of DCs were observed. Paroxetine, when used in vitro and in CIA mice, restrained the maturation of DCs and the differentiation of CD8 + T cells, and induced the proportion of T regs . Paroxetine inhibited the secretion of pro-inflammatory cytokines, the expression of C-C motif chemokine receptor 7 in DCs and T cells. Simultaneously, paroxetine upregulated the expression of programmed death ligand 1, and anti-inflammatory cytokines. Additionally, paroxetine inhibited the PI3K-AKT-mTOR metabolic pathway in both DCs and T cells. This was associated with a reduction in mitochondrial membrane potential and changes in the utilization of glucose and lipids, particularly in DCs. Paroxetine reversed PI3K-AKT pathway activation induced by 740 Y-P (a PI3K agonist) through inhibiting the interaction between GRK2 and PI3K in DCs and T cells. CONCLUSION Paroxetine exerts an immunosuppressive effect by targeting GRK2, which subsequently inhibits the metabolism-related PI3K-AKT-mTOR pathway of DCs and T cells in RA.
G-Protein-Coupled Receptor Kinase 2/metabolism* ; Arthritis, Rheumatoid/immunology* ; Animals ; Dendritic Cells/metabolism* ; Paroxetine/therapeutic use* ; Proto-Oncogene Proteins c-akt/metabolism* ; Mice ; Humans ; Mice, Inbred C57BL ; Signal Transduction/drug effects* ; Male ; Phosphatidylinositol 3-Kinases/metabolism* ; Lymphocyte Activation/drug effects* ; Female ; T-Lymphocytes/metabolism* ; Middle Aged

BACKGROUND: Regulatory dendritic cell (DCreg) subset exhibits a unique capacity for inducing immune tolerance among the variety subsets of dendritic cells (DCs) within gut-associated lymphoid tissues (GALTs). Fms-like tyrosine kinase 3 ligand (FLT3L) is involved in the differentiation of DCregs and the subsequent expansion of regulatory T-cells (Tregs) mediated by DCregs, though the precise mechanism remains poorly understood. This study aimed to explore the expansion mechanism of Treg induced by DCreg and the role of FLT3L in this process. METHODS: DCregs were distinguished from other DC subsets isolated from GALTs of BALB/c mice through a mixed lymphocyte reaction assay. The functions and mechanisms by which FLT3L promoted Treg expansion via DCregs were investigated in vitro through co-culture experiments involving DCregs and either CD4 + CD25 - T-cells or CD4 + CD25 + T-cells. Additionally, an in vivo experiment was conducted using a dextran sulfate sodium (DSS)-induced colitis model in mice. RESULTS: CD103 + CD11b + DC exhibited DCreg-like functionality and was identified as DCreg for subsequent investigation. Analysis of Foxp3 + Treg percentages within a co-culture system of CD4 + CD25 - T-cells and DCregs, with or without FLT3L, demonstrated the involvement of the FLT3/FLT3L axis in driving the differentiation of precursor T-cells into Foxp3 + Tregs induced by DCregs. Cell migration and co-culture assays revealed that the FLT3/FLT3L axis enhanced DCreg migration toward Tregs via the Rho pathway. Additionally, it was observed that DCregs could promote Treg proliferation through the Notch pathway, as inhibition of Notch signaling by DAPT (N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester) suppressed Treg expansion within the co-culture system of DCregs and CD4 + T-cells or CD4 + CD25 + T-cells. Furthermore, the FLT3/FLT3L axis influenced JAG1 expression in DCregs, indirectly modulating Treg expansion. In vivo experiments further established that FLT3L promoted DCreg expansion and restored Treg balance in DSS-induced colitis models, thereby ameliorating colitis symptoms in mice. CONCLUSION The FLT3/FLT3L axis is integral to the maintenance of DCreg function in Treg expansion.
Animals ; T-Lymphocytes, Regulatory/immunology* ; Dendritic Cells/immunology* ; Mice ; Mice, Inbred BALB C ; Membrane Proteins/metabolism* ; Receptors, Notch/metabolism* ; Lymphoid Tissue/metabolism* ; Signal Transduction/physiology* ; Coculture Techniques ; Flow Cytometry

Objective This study investigated the regulatory effect of high mobility group protein B1 (HMGB1) in the peripheral blood of patients with primary immune thrombocytopenia (ITP) on myeloid dendritic cells (mDC) and Th17/regulatory T cells (Treg) balance. Methods The study enrolled 30 newly diagnosed ITP patients and 30 healthy controls.Flow cytometry was used to measure the proportion of mDC, Th17, and Treg cells in the peripheral blood of ITP patients and healthy controls. ELISA was conducted to quantify the serum levels of HMGB1, interleukin 6 (IL-6), IL-23, IL-17, and transforming growth factor β(TGF-β). The mRNA levels of retinoic acid-related orphan receptor γt(RORγt) and forehead box P3(FOXP3) were detected by real-time PCR. The correlation between the abovementioned cells, cytokines, and platelet count was assessed using Pearson linear correlation analysis. Results The proportion of Th17 cells and the expression levels of HMGB1, IL-6, IL-23, IL-17 and the level of RORγt mRNA in the peripheral blood of ITP patients were higher than those in healthy controls. However, the Treg cell proportion and TGF-β level were lower in ITP patients than those in healthy controls. In patients with ITP, the proportion of mDC and the level of FOXP3 mRNA did not show significant changes. The proportion of mDC cells was significantly correlated with the expression of IL-6 and IL-23. Moreover, the expression of HMGB1 showed a significant correlation with the expression of mDC, IL-6, IL-23, RORγt mRNA, and IL-17. Notably, both the proportion of mDC cells and the expression of HMGB1 were negatively correlated with platelet count. Conclusion The high expression of HMGB1 in peripheral blood of ITP patients may induce Th17/Treg imbalance by promoting the maturation of mDC and affecting the secretion of cytokines, thereby potentially playing a role in the immunological mechanism of ITP.
Humans ; Th17 Cells/cytology* ; HMGB1 Protein/genetics* ; T-Lymphocytes, Regulatory/cytology* ; Female ; Male ; Dendritic Cells/metabolism* ; Adult ; Middle Aged ; Purpura, Thrombocytopenic, Idiopathic/genetics* ; Nuclear Receptor Subfamily 1, Group F, Member 3/genetics* ; Young Adult ; Interleukin-23/blood* ; Interleukin-17/blood* ; Interleukin-6/blood* ; Forkhead Transcription Factors/genetics* ; Myeloid Cells/cytology* ; Aged

Myeloid-derived cells (MDCs) are crucial in immune response and tissue homeostasis. They have high functional plasticity and can be polarized according to microenvironment signals. These cells, including macrophages, neutrophils, and dendritic cells (DCs), exhibit different functional polarization states in different pathological environments and are involved in the occurrence and development of diseases such as inflammation and tumors. Studies have shown that metabolic reprogramming plays a key role in the functional polarization of MDCs, affecting the cellular energy supply and regulating immune function. This paper reviews classification, function and polarization mechanism of MDCs and discusses metabolic reprogramming. In addition, the therapeutic strategies targeting MDC are summarized, which is expected to provide new targets for tumor immunotherapy.
Humans ; Tumor Microenvironment/immunology* ; Myeloid Cells/metabolism* ; Neoplasms/pathology* ; Animals ; Immunotherapy/methods* ; Dendritic Cells/immunology* ; Macrophages/immunology*

Objective To investigate how culture duration affects the expression of immune membrane proteins in human monocyte-derived dendritic cells (DCs) and their exosomes (DEXs). Methods Human monocytes were induced with recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin 4 (IL-4) to differentiate into DCs and were subsequently matured with tumor necrosis factor α(TNF-α). Exosomes were isolated by ultracentrifugation, and DEXs were identified by transmission electron microscopy and Amnis imaging flow cytometry, which were also used to quantify the expression of immune membrane proteins on DCs and DEXs. Results On the 10th day of culture, DCs displayed high surface expression of CD11c, CD80, CD86, major histocompatibility complex class I (MHC-I), and MHC-II. Expression peaked at day 18(CD11c: 78.66%±20.33%, CD80: 76.41%±10.02%, CD86: 96.43%±0.43%, MHC-I: 84.71%±2.96%, MHC-II: 80.01%±7.03%). After day 24, the overall expression showed a declining trend, with statistically significant differences observed for all markers except CD80 and MHC-II. By day 30, 80% of the DCs still expressed CD80, CD86, and MHC-II. The expression of immune membrane proteins on DEX surfaces also reached its peak on day 18, followed by an overall decline with prolonged culture time, with statistically significant differences observed for all markers except CD80. Correlation analysis revealed a significant positive relationship between the expression levels of immune membrane proteins on DC and DEX surfaces (CD11c: r=0.98; CD80: r=0.65; CD86: r=0.82; MHC-I: r=0.86; MHC-II: r=0.93). Conclusion Human monocyte-derived DCs in vitro express high expression of immune membrane proteins and maintain stable expression over a specific period. The exosomes secreted by these cells similarly demonstrate high surface expression of immune membrane proteins, with temporal trends aligned with those of the parent DCs.
Humans ; Dendritic Cells/immunology* ; Exosomes/immunology* ; Monocytes/metabolism* ; Cells, Cultured ; Time Factors ; B7-1 Antigen/metabolism* ; Membrane Proteins/immunology* ; Cell Culture Techniques/methods* ; B7-2 Antigen/metabolism* ; Cell Differentiation ; CD11c Antigen/metabolism* ; Granulocyte-Macrophage Colony-Stimulating Factor/pharmacology*

OBJECTIVE: To review the role of dendritic cells (DC) in immune metabolism of rheumatoid arthritis (RA). METHODS: Literature on the role of DC in the immune metabolism of RA was extensively reviewed in recent years, and the metabolic characteristics of RA, the role of DC in RA, the correlation between the immune metabolism of DC and pathogenesis of RA, and the treatment were summarized and analyzed. RESULTS: DC promotes the progression of RA under hypoxia, increased glycolysis, inhibition of oxidative phosphorylation, and decreased lipid metabolism. Moreover, many DCs (especially conventional DC and monocyte-derived DC) have different functions and phenotypic characteristics in RA, which are closely related to the occurrence and development of RA. CONCLUSION DC plays an important role in the immune metabolism of RA, and immunometabolism therapy based on DC can provide targeted therapy for the treatment of RA.
Dendritic Cells/immunology* ; Arthritis, Rheumatoid/immunology* ; Humans ; Glycolysis ; Oxidative Phosphorylation ; Lipid Metabolism ; Animals

This study developed ferritin-based nanoparticles carrying the African swine fever virus (ASFV) p30 protein and evaluated their immunogenicity, aiming to provide an experimental basis for the research on nanoparticle vaccines against ASFV. Initially, the gene sequences encoding the p30 protein and SpyTag were fused and inserted into the pCold-I vector to create the pCold-p30 plasmid. The gene sequences encoding SpyCatcher and ferritin were fused and then inserted into the pET-28a(+) vector to produce the pET-F-np plasmid. Both plasmids were expressed in Escherichia coli upon induction. Subsequently, the affinity chromatography-purified p30 protein was conjugated with ferritin in vitro, and the p30-ferritin (F-p30) nanoparticles were purified by size-exclusion chromatography. The morphology and structural integrity of F-p30 nanoparticles were examined by a particle size analyzer and transmission electron microscopy. Mice were immunized with F-p30 nanoparticles, and the humoral and cellular immune responses were assessed. The results showed that F-p30 nanoparticles were successfully prepared, with the particle size of approximately 20 nm. F-p30 nanoparticles were efficiently internalized by bone marrow-derived dendritic cells (BMDCs) cells in vitro. Compared with the p30 protein alone, F-p30 nanoparticles induced elevated levels of specific antibodies and cytokines in mice and stimulated the proliferation of follicular helper T cell (T_FH) and germinal center B cell (GCB) in lymph nodes as well as CD4⁺ and CD8⁺ T cells in the spleen. In conclusion, we successfully prepared F-p30 nanoparticles which significantly enhanced the immunogenicity of p30 protein, giving insights into the development of vaccines against ASFV.
Animals ; Nanoparticles/chemistry* ; Mice ; African Swine Fever Virus/genetics* ; Ferritins/chemistry* ; Swine ; Viral Vaccines/genetics* ; African Swine Fever/immunology* ; Mice, Inbred BALB C ; Viral Proteins/genetics* ; Escherichia coli/metabolism* ; Dendritic Cells/immunology* ; Immunogenicity, Vaccine ; Antibodies, Viral/blood* ; Female ; Capsid Proteins/genetics*

Bone substitute material implantation has become an important treatment strategy for the repair of oral and maxillofacial bone defects. Recent studies have shown that appropriate inflammatory and immune cells are essential factors in the process of osteoinduction of bone substitute materials. Previous studies have mainly focused on innate immune cells such as macrophages. In our previous work, we found that T lymphocytes, as adaptive immune cells, are also essential in the osteoinduction procedure. As the most important antigen-presenting cell, whether dendritic cells (DCs) can recognize non-antigen biomaterials and participate in osteoinduction was still unclear. In this study, we found that surgical trauma associated with materials implantation induces necrocytosis, and this causes the release of high mobility group protein-1 (HMGB1), which is adsorbed on the surface of bone substitute materials. Subsequently, HMGB1-adsorbed materials were recognized by the TLR4-MYD88-NFκB signal axis of dendritic cells, and the inflammatory response was activated. Finally, activated DCs release regeneration-related chemokines, recruit mesenchymal stem cells, and initiate the osteoinduction process. This study sheds light on the immune-regeneration process after bone substitute materials implantation, points out a potential direction for the development of bone substitute materials, and provides guidance for the development of clinical surgical methods.
Biocompatible Materials/metabolism* ; HMGB1 Protein/metabolism* ; Myeloid Differentiation Factor 88/metabolism* ; Bone Substitutes/metabolism* ; Dendritic Cells/metabolism*

Objective To clarify the effect and mechanism of tumor antigen-loaded dendritic cells (Ag-DCs) combined with cytokine-induced killers (CIKs) on the killing of esophageal cancer tumor cells. Methods Peripheral blood DCs and CIKs were induced and cultured, and the DCs were loaded with tumor antigen to obtain Ag-DCs, and Ag-DCs were co-cultured with CIKs. The experiment was divided into CIK group, DC combined with CIK group, Ag-DC combined with CIK group. Flow cytometry was used to detect the phenotype of cells. MTT assay was employed to determine the killing activity against EC9706 cells. Annexin V-FITC/PI double staining was used to detect the apoptosis rate of cells, immunofluorescence staining to detect the expression of phosphorylated apoptotic signal-regulated kinase 1 (p-ASK1) and Western blot analysis to detect the expression of ASK1 pathway related proteins. A nude mouse model of esophageal cancer transplantation tumor was constructed and divided into control group, DC combined with CIK group and Ag-DC combined with CIK group. The corresponding immune cells were injected into the tail vein for treatment and the tumor volume was measured every 2 days. After 21 days, all nude mice were sacrificed with the tumors taken out. HE staining was used to observe the tumor pathological changes and immunohistochemical staining was performed to detect the expression of ki67 and ASK1 in the tumor tissue. Results Comparedwith the CIK group alone and the DC combined with CIK group, the ratio of CD3⁺ CD8⁺ and CD3⁺ CD56⁺ in the cells significantly increased after Ag-DCs and CIKs co-culture, along with the increased killing rate of EC9706 cells, increased apoptosis rate of EC9706 cells, and the improved activation level of ASK1. Compared with the CIK group and the DC combined with CIK group, the growth of the transplanted tumor in nude mice treated with Ag-DCs combined with CIKs was significantly inhibited, and after 21 days, it was observed that the tumor tissue mass in this group was relatively smaller, with sparsely arranged cells in the tumor tissue and a decline in the positive rate of ki67 in tumor tissue, while the positive rate of ASK1 was significantly increased. Conclusion Co-cultivation of tumor antigen-loaded DCs with CIKs can significantly increase the killing activity of esophageal cancer tumor cells. The mechanism of action may be related to the activation of the ASK1 pathway.
Animals ; Humans ; Mice ; Antigens, Neoplasm ; Cytokine-Induced Killer Cells ; Cytokines/metabolism* ; Cytotoxicity, Immunologic ; Dendritic Cells ; Esophageal Neoplasms/therapy* ; Ki-67 Antigen ; Mice, Nude

Immunoglobulin (IgG) glycosylation affects the effector functions of IgG in a myriad of biological processes and has been closely associated with numerous autoimmune diseases, including systemic lupus erythematosus (SLE), thus underlining the pathogenic role of glycosylation aberration in autoimmunity. This study aims to explore the relationship between IgG sialylation patterns and lupus pregnancy. Relative to that in serum samples from the control cohort, IgG sialylation level was aberrantly downregulated in serum samples from the SLE cohort at four stages (from preconception to the third trimester of pregnancy) and was significantly associated with lupus activity and fetal loss during lupus pregnancy. The type I interferon signature of pregnant patients with SLE was negatively correlated with the level of IgG sialylation. The lack of sialylation dampened the ability of IgG to suppress the functions of plasmacytoid dendritic cells (pDCs). RNA-seq analysis further revealed that the expression of genes associated with the spleen tyrosine kinase (SYK) signaling pathway significantly differed between IgG- and deSia-IgG-treated pDCs. This finding was confirmed by the attenuation of the ability to phosphorylate SYK and BLNK in deSia-IgG. Finally, the coculture of pDCs isolated from pregnant patients with SLE with IgG/deSia-IgG demonstrated the sialylation-dependent anti-inflammatory function of IgG. Our findings suggested that IgG influences lupus activity through regulating pDCs function via the modulation of the SYK pathway in a sialic acid-dependent manner.
Humans ; Pregnancy ; Female ; Lupus Erythematosus, Systemic/pathology* ; Signal Transduction ; N-Acetylneuraminic Acid/metabolism* ; Immunoglobulin G ; Dendritic Cells/pathology*