BACKGROUND: Hepatic inflammatory cell accumulation and the subsequent systematic inflammation drive acute-on-chronic liver failure (ACLF) development. Previous studies showed that the vagus nerve exerts anti-inflammatory activity in many inflammatory diseases. Here, we aimed to identify the key molecule mediating the inflammatory process in ACLF and reveal the neuroimmune communication arising from the vagus nerve and immunological disorders of ACLF. METHODS: Proteomic analysis was performed and validated in ACLF model mice or patients, and intervention animal experiments were conducted using neutralizing antibodies. PNU-282987 (acetylcholine receptor agonist) and vagotomy were applied for perturbing vagus nerve activity. Single-cell RNA sequencing (scRNA-seq), flow cytometry, immunohistochemical and immunofluorescence staining, and clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) technology were used for in vivo or in vitro mechanistic studies. RESULTS: The unbiased proteomics identified C-X-C motif chemokine ligand 9 (CXCL9) as the greatest differential protein in the livers of mice with ACLF and its relation to the systematic inflammation and mortality were confirmed in patients with ACLF. Interventions on CXCL9 and its receptor C-X-C chemokine receptor 3 (CXCR3) improved liver injury and decreased mortality of ACLF mice, which were related to the suppressing of hepatic immune cells' accumulation and activation. Vagus nerve stimulation attenuated while vagotomy aggravated the expression of CXCL9 and the severity of ACLF. Blocking CXCL9 and CXCR3 ameliorated liver inflammation and increased ACLF-associated mortality in ACLF mice with vagotomy. scRNA-seq revealed that hepatic macrophages served as the major source of CXCL9 in ACLF and were validated by immunofluorescence staining and flow cytometry analysis. Notably, the expression of CXCL9 in macrophages was modulated by vagus nerve-mediated cholinergic signaling. CONCLUSIONS Our novel findings highlighted that the neuroimmune communication of the vagus nerve-macrophage-CXCL9 axis contributed to ACLF development. These results provided evidence for neuromodulation as a promising approach for preventing and treating ACLF.
Animals ; Mice ; Chemokine CXCL9/metabolism* ; Vagus Nerve/physiology* ; Acute-On-Chronic Liver Failure/metabolism* ; Humans ; Male ; Mice, Inbred C57BL ; Proteomics ; Flow Cytometry ; Receptors, CXCR3/metabolism*

BACKGROUND: Peripheral helper T (T PH ) cells are uniquely positioned within pathologically inflamed non-lymphoid tissues to stimulate B-cell responses and antibody production. However, the phenotype, function, and clinical relevance of T PH cells in hepatocellular carcinoma (HCC) are currently unknown. METHODS: Blood, tumor, and peritumoral liver tissue samples from 39 HCC patients (Sep 2016-Aug 2017) and 101 HCC patients (Sep 2011-Dec 2012) at the Third Affiliated Hospital of Sun Yat-sen University were used. Flow cytometry was used to quantify the expression, phenotype, and function of T PH cells. Log-rank tests were performed to evaluate disease-free survival and overall survival in samples from 39 patients and 101 patients with HCC. T PH cells, CD19 + B cells, and T follicular helper (T FH ) cells were cultured separately in vitro or isolated from C57/B6L mice in vivo for functional assays. RESULTS: T PH cells highly infiltrated tumor tissues, which was correlated with tumor size, early recurrence, and shorter survival time. The tumor-infiltrated T PH cells showed a unique ICOS hi CXCL13 + IL-21 - MAF + BCL-6 - phenotype and triggered naïve B-cell differentiation into regulatory B cells. Triggering programmed cell death protein 1 (PD-1) induced the production of C-X-C motif chemokine ligand 13 (CXCL13) by T PH cells, which then suppressed tumor-specific immunity and promoted disease progression. CONCLUSION Our study reveals a novel regulatory mechanism of T PH cell-regulatory B-cell-mediated immunosuppression and provides an important perspective for determining the balance between the differentiation of protumorigenic T PH cells and that of antitumorigenic T FH cells in the HCC microenvironment.
Carcinoma, Hepatocellular/metabolism* ; Liver Neoplasms/metabolism* ; Humans ; T-Lymphocytes, Helper-Inducer/metabolism* ; Animals ; Mice ; Male ; Female ; Mice, Inbred C57BL ; Middle Aged ; B-Lymphocytes, Regulatory/metabolism* ; Flow Cytometry ; Interleukin-21 ; Aged ; Chemokine CXCL13/metabolism*

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

BACKGROUND: Immunosuppression is closely related to the pathogenesis of sepsis, but the underlying mechanisms have not yet been fully elucidated. In this study, we aimed to examine the role of the Sterile Alpha Motif, Src Homology 3 domain and nuclear localization signal 1 (SAMSN1) in sepsis and elucidate its potential molecular mechanism in sepsis induced immunosuppression. METHODS: RNA sequencing databases were used to validate SAMSN1 expression in sepsis. The impact of SAMSN1 on sepsis was verified using gene knockout mice. Flow cytometry was employed to delineate how SAMSN1 affects immunity in sepsis, focusing on immune cell types and T cell functions. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9)-mediated gene editing in RAW264.7 macrophages enabled interrogation of SAMSN1 's regulatory effects on essential macrophage functions, including cell proliferation and phagocytic capacity. The mechanism of SAMSN1 in the interaction between macrophages and T cells was investigated using the RAW264.7 cell line and primary cell lines. RESULTS: SAMSN1 expression was significantly increased in patients with sepsis and was positively correlated with sepsis mortality. Genetic deletion of Samsn1 in murine sepsis model improved T cell survival, elevated T cell cytolytic activity, and activated T cell signaling transduction. Concurrently, Samsn1 knockout augmented macrophage proliferation capacity and phagocytic efficiency. In macrophage, SAMSN1 binds to Kelch-like epichlorohydrin-associated protein 1 (KEAP1), causing nuclear factor erythroid 2-related factor 2 (NRF2) to dissociate from the KEAP1-NRF2 complex and translocate into the nucleus. This promotes the transcription of the coinhibitory molecules CD48/CD86/carcinoembryonic antigen related cell adhesion molecule 1 (CEACAM1), which bind to their corresponding receptors natural killer cell receptor 2B4/CD152/T cell immunoglobulin and mucin domain-containing protein 3 (TIM3) on the surface of T cells, inducing T-cell exhaustion. CONCLUSIONS SAMSN1 deletion augmented adaptive T cell immunity and macrophage phagocytic-proliferative dual function. Furthermore, it mediates the KEAP1-NRF2 axis, which affects the expression of coinhibitory molecules on macrophages, leading to T-cell exhaustion. This novel immunosuppression mechanism potentially provides a candidate molecular target for sepsis immunotherapy.
Animals ; NF-E2-Related Factor 2/metabolism* ; Mice ; Macrophages/immunology* ; Sepsis/metabolism* ; Kelch-Like ECH-Associated Protein 1/genetics* ; T-Lymphocytes/immunology* ; Humans ; Signal Transduction/physiology* ; RAW 264.7 Cells ; Mice, Knockout ; Mice, Inbred C57BL ; Male ; Flow Cytometry ; T-Cell Exhaustion

BACKGROUND: Macrophage polarization anomalies and dysfunction play a crucial role in the pathogenesis of immune thrombocytopenia (ITP). Itaconate is a Krebs cycle-derived immunometabolite synthesized by myeloid cells to modulate cellular metabolism and inflammatory responses. This study aimed to evaluate the immunoregulatory effects of an itaconate derivative on macrophages in patients with ITP. METHODS: Peripheral blood-derived macrophages from patients with ITP and healthy controls were treated with 4-octyl itaconate (4-OI), a derivative of itaconate that can penetrate the cell membrane. Macrophage polarization, antigen-presenting functions, and phagocytic capability were measured via flow cytometry and enzyme-linked immunosorbent assay (ELISA). Macrophage glycolysis in patients with ITP and the metabolic regulatory effect of 4-OI were detected using a Seahorse XFe96 Analyzer. An active murine model of ITP was used to evaluate the therapeutic effects of 4-OI in vivo . RESULTS: 4-OI reduced the levels of CD80 and CD86 in M1 macrophages and suppressed the release of tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 pro-inflammatory cytokines, suggesting that 4-OI could hinder the polarization of macrophages toward an M1 phenotype. We found that 4-OI pretreated M1 macrophages reduced the proliferation of CD4 + T cells and promoted the differentiation of regulatory T cells. In addition, after 4-OI treatment, the phagocytic capacity of M1 macrophages toward antibody-coated platelets decreased significantly in patients with ITP. In addition, the glycolytic function of M1 macrophages was elevated in individuals with ITP compared to those in healthy controls. 4-OI treatment downregulated glycolysis in M1 macrophages. The glycolysis inhibitor 2-deoxy-d-glucose (2-DG) also inhibited the polarization of M1 macrophages and restored their functions. In vivo , 4-OI treatment significantly increased platelet counts in the active ITP murine model. CONCLUSIONS Itaconate derivative 4-OI inhibited M1 macrophage polarization and restored impaired functions through metabolic reprogramming. This study provides a novel therapeutic option for ITP.
Macrophages/metabolism* ; Humans ; Animals ; Succinates/pharmacology* ; Mice ; Male ; Female ; Adult ; Middle Aged ; Flow Cytometry ; Tumor Necrosis Factor-alpha/metabolism* ; Enzyme-Linked Immunosorbent Assay ; Purpura, Thrombocytopenic, Idiopathic/metabolism* ; Glycolysis/drug effects* ; Metabolic Reprogramming

Corticotomy is a clinical procedure to accelerate orthodontic tooth movement characterized by the regional acceleratory phenomenon (RAP). Despite its therapeutic effects, the surgical risk and unclear mechanism hamper the clinical application. Numerous evidences support macrophages as the key immune cells during bone remodeling. Our study discovered that the monocyte-derived macrophages primarily exhibited a pro-inflammatory phenotype that dominated bone remodeling in corticotomy by CX3CR1^CreERT2; R26^GFP lineage tracing system. Fluorescence staining, flow cytometry analysis, and western blot determined the significantly enhanced expression of binding immunoglobulin protein (BiP) and emphasized the activation of sensor activating transcription factor 6 (ATF6) in macrophages. Then, we verified that macrophage specific ATF6 deletion (ATF6^f/f; CX3CR1^CreERT2 mice) decreased the proportion of pro-inflammatory macrophages and therefore blocked the acceleration effect of corticotomy. In contrast, macrophage ATF6 overexpression exaggerated the acceleration of orthodontic tooth movement. In vitro experiments also proved that higher proportion of pro-inflammatory macrophages was positively correlated with higher expression of ATF6. At the mechanism level, RNA-seq and CUT&Tag analysis demonstrated that ATF6 modulated the macrophage-orchestrated inflammation through interacting with Tnfα promotor and augmenting its transcription. Additionally, molecular docking simulation and dual-luciferase reporter system indicated the possible binding sites outside of the traditional endoplasmic reticulum-stress response element (ERSE). Taken together, ATF6 may aggravate orthodontic bone remodeling by promoting Tnfα transcription in macrophages, suggesting that ATF6 may represent a promising therapeutic target for non-invasive accelerated orthodontics.
Animals ; Mice ; Macrophages/metabolism* ; Tumor Necrosis Factor-alpha/genetics* ; Tooth Movement Techniques/methods* ; Activating Transcription Factor 6/metabolism* ; Bone Remodeling ; Flow Cytometry ; Blotting, Western

Protein liquid-liquid phase separation (LLPS), a pivotal phenomenon intricately linked to cellular processes, is regulated by various other proteins. However, there is still a lack of high-throughput methods for screening protein regulators of LLPS in target proteins. Here, we developed a CRISPR/Cas9-based screening method to identify protein phase separation regulators by integrating bimolecular fluorescence complementation (BiFC) and fluorescence-activated cell sorting (FACS). Using this newly developed method, we screened the RNA-binding proteins that regulate PABPN1 phase separation and identified the tumor suppressor QKI as a promoter of PABPN1 phase separation. Furthermore, QKI exhibits decreased expression levels and diminished nuclear localization in colorectal cancer cells, resulting in reduced PABPN1 phase separation, which, in turn, promotes alternative polyadenylation (APA), cell proliferation, and migration in colorectal cancer.
Humans ; Colorectal Neoplasms/genetics* ; RNA-Binding Proteins/genetics* ; Poly(A)-Binding Protein I/genetics* ; CRISPR-Cas Systems ; Flow Cytometry ; Cell Proliferation ; Cell Line, Tumor ; Cell Movement

This study aims to establish a method for counting the viral particles in adenovirus vector-based vaccines. Nano-flow cytometry was employed to analyze the viral particles in adenovirus-based vector vaccines at the single-particle level. Monodisperse silica nanoparticles with a refractive index close to that of the virus were selected as the particle size standard to calculate the viral particle size, which was then compared with the results obtained from transmission electron microscopy (TEM) to determine the gating strategy. Subsequently, a particle count standard was employed to calculate the viral particle concentration. The established method demonstrated good linearity, accuracy, precision, and specificity. The results of determined viral particle concentration showed a good correlation with the infectious titer. Compared with the conventional OD₂₆₀ method, nano-flow cytometry can directly measure the viral particle concentration and indicate whether the sample has been disassembled according to changes in viral particle concentration and size, thus more accurately reflecting the actual infectious potency of the sample. The novel quantification method established in this study is capable of indicating the efficacy of adenovirus vector-based vaccines and provides effective technical support for the quality control of such products.
Adenoviridae/genetics* ; Genetic Vectors ; Flow Cytometry/methods* ; Virion/isolation & purification* ; Particle Size ; Nanoparticles ; Viral Vaccines

Actinomycetes are important producers of high-value natural products, and the engineering of actinomycetes to enhance the biosynthesis of target natural products has long been a hot research topic in the scientific community. However, non-rational engineering methods suffer from low beneficial mutation rates, which limit the efficiency of mutant screening. The integration of high-throughput screening (HTS) technologies can effectively enhance the screening efficiency of elite mutants and significantly shorten the cycle of actinomycete strain engineering. This review comprehensively discusses various HTS technologies suitable for the engineering of actinomycete strains and compares them in terms of application scenarios, advantages, and disadvantages. HTS technologies include microplate-based screening, antimicrobial activity screening, antibiotic resistance screening, fluorescence-activated cell sorting (FACS), and fluorescence-activated droplet sorting (FADS). Additionally, this review summarizes the applications of these technologies in assisting actinomycete strain engineering and enhancing the yields of target compounds. The development and application of HTS technologies have not only facilitated the exploration of natural product resources in actinomycetes but also provided strong support for the rapid and efficient construction of high-performance engineered actinomycete strains.
Actinobacteria/metabolism* ; High-Throughput Screening Assays/methods* ; Genetic Engineering/methods* ; Biological Products/metabolism* ; Flow Cytometry ; Metabolic Engineering/methods*

OBJECTIVE: To explore the immunophenotypic characteristics of bone marrow granulocytes (G) and their clinical significance in patients with multiple myeloma (MM). METHODS: The granulocyte immunophenotypes of bone marrow in 70 MM patients (MM group) and 40 anemia patients (control group) were detected by flow cytometry, and its correlation with clinical characteristics was further analyzed. Univariate and multivariate regression analysis were used to screen factors that affected prognosis. RESULTS: The CD56⁺G%, CD13⁺G%, CD22⁺G% and CD117⁺G% in MM group were higher than those in the control group (all P <0.05). CD56⁺G% and CD117⁺G% in CR⁺VGPR group were significantly lower than those in PR+MR+PD group (both P <0.05). The CD10⁺G% in RISS Ⅲ stage and Ca²⁺ ≥2.65 mmol/L groups were increased (both P <0.05). The CD56⁺G% in elevated lactate dehydrogenase, β₂-microglobulin≥5.5 mg/L and hemoglobin <85 g/L groups were increased (all P <0.05), while the CD117⁺G% in high-risk cytogenetic positive group was decreased (P <0.05). The expression rate of CD molecules on granulocytes was divided into low (L) and high (H) groups according to the median value. The overall survival (OS) of the LCD56⁺G%, LCD13⁺G% and LCD22⁺G% groups was significantly prolonged (all P <0.05). CD13⁺G% and CD22⁺G% were independent risk factors for OS in MM patients (HR=0.443, 0.410, both P <0.05). CONCLUSION The CD56⁺G%, CD10⁺G% and CD117⁺G% are closely correlated with clinical features in MM patients, while CD13⁺G% and CD22⁺G% are closely correlated with prognosis. Detection of CD molecules expression on granulocytes may be used to evaluate prognosis and guide treatment.
Humans ; Multiple Myeloma/immunology* ; Granulocytes/immunology* ; Prognosis ; Immunophenotyping ; Male ; Bone Marrow ; Female ; Flow Cytometry ; Middle Aged ; Aged ; Clinical Relevance