OBJECTIVE: To explore the effect and mechanism of DNA methyltransferase 1 (DNMT1) knockout on the inhibition of acute myeloid leukemia (AML) by natural killer (NK) cells. METHODS: The peripheral blood NK cells of AML patients and controls were collected, and the mRNA and protein level of DNMT1 were measured by PCR and Western blot, respectively. The DNMT1 knockout mice were constructed to obtain NK^DNMT1-/- cells. The NK cells were stimulated with interleukin (IL)-12, IL-15, and IL-18 to construct memory NK cells, and then the interferon-γ (IFN-γ) levels were measured by ELISA. After co-culturing with memory NK cells and HL60 cells, the killing effect of NK^DNMT1-/- cells on HL60 cells was detected by LDH assay. Then, the HL60 cell apoptosis and NK cell NKG2D level were measured by flow cytometry. The perforin and granzyme B protein levels of NK cells were measured by Western blot. The AML model mice were constructed by injecting HL60 cells into the tail vein, meanwhile, memory NK cells were also injected, and then the mouse weights, CD33 positive rates, and survival time were detected. RESULTS: The mRNA and protein levels of DNMT1 in NK cells of AML patients were significantly higher than those in the control group (both P < 0.01), while the IFN-γ level induced by interleukin was significantly lower than that in the control group (P < 0.05). Compared with NK^DNMT1+/+ cells, the ability of NK^DNMT1-/- cells to secrete IFN-γ after interleukin stimulation was significantly increased (P < 0.05). The killing and apoptosis-inducing effects of NK^DNMT1-/- cells on HL60 cells were significantly stronger than those of NK^DNMT1+/+ cells (both P < 0.05). The NKG2D level and expression of perforin and granzyme B of NK^DNMT1-/- cells were significantly increased compared with NK^DNMT1+/+ cells (all P < 0.05). Compared with AML mice injected with NK^DNMT1+/+ cells, AML mice injected with NK^DNMT1-/- cells showed significantly increased body weight, decreased CD33 positive rate, and prolonged survival time (all P < 0.05). CONCLUSION Knocking out DNMT1 can enhance the inhibitory effect of NK cells on AML, which may be related to enhancing NK cell memory function.
Killer Cells, Natural/metabolism* ; Animals ; Leukemia, Myeloid, Acute ; Humans ; DNA (Cytosine-5-)-Methyltransferase 1 ; Mice ; Mice, Knockout ; HL-60 Cells ; Apoptosis ; Interferon-gamma/metabolism* ; Granzymes/metabolism* ; Perforin/metabolism* ; NK Cell Lectin-Like Receptor Subfamily K/metabolism*

OBJECTIVE: To investigate the mechanism of circular RNA RAD18 (CircRAD18 ) in regulating daunorubicin (DNR) resistance in acute myeloid leukemia (AML) cells through the miR-185-5p/hepatoma-derived growth factor ( HDGF) axis. METHODS: Real-time fluorescence quantitative PCR and immunoblotting were applied to detect the expression of CircRAD18 , miR-185-5p, and HDGF in human AML cell lines HL-60, U937, and human AML drug-resistant cell line KG1a. KG1a cells were cultured in vitro and randomly divided into control group, DNR group, DNR+negative control group, DNR+CircRAD18 knockdown group, and DNR+CircRAD18 knockdown+miR-185-5p inhibitor group. After transfection, real-time fluorescence quantitative PCR and immunoblotting were applied to detect the expression of CircRAD18 , miR-185-5p, and HDGF of cells, CCK-8 method and Ki-67 immunofluorescence staining were applied to detect cell proliferation, flow cytometry was applied to detect cell apoptosis, and immunoblotting was applied to detect the expression of cell proliferation, apoptosis and drug resistance related proteins in each group. The double luciferase reporter gene experiment was applied to detect the targeting regulation of CircRAD18 on miR-185-5p, and miR-185-5p on HDGF in KG1a cells. RESULTS: Compared with HL-60 and U937 cells, the expression of CircRAD18 , and HDGF mRNA and protein in KG1a cells increased (all P <0.05), while miR-185-5p decreased ( P <0.05). Compared with the control group, the CircRAD18 expression, HDGF mRNA and protein expression, cell viability, proliferation rate, and PCNA, Bcl-2, BCRP, and P-gp protein expression in the DNR+CircRAD18 knockdown group decreased (all P <0.05), while miR-185-5p expression, apoptosis rate, and Bax protein expression increased (all P <0.05). There were no obvious changes in all indicators of cells in the DNR group compared with control group ( P >0.05). Compared with the DNR group, the CircRAD18 expression, HDGF mRNA and protein expression, cell viability, proliferation rate, PCNA, Bcl-2, BCRP, and P-gp protein expression in the DNR+CircRAD18 knockdown group decreased (all P < 0.05), while miR-185-5p expression, apoptosis rate, and Bax protein expression increased (all P < 0.05). There were no obvious changes in all indicators of cells in the DNR+negative control group compared with DNR group (P >0.05). Compared with the DNR+CircRAD18 knockdown group, the HDGF mRNA and protein expression, cell viability, proliferation rate, PCNA, Bcl-2, BCRP, and P-gp protein expression in the DNR+CircRAD18 knockdown+miR-185-5p inhibitor group increased (all P < 0.05), while miR-185-5p expression, apoptosis rate, and Bax protein expression decreased (all P < 0.05). CircRAD18 was able to target and down-regulate the expression of miR-185-5p in KG1a cells, and miR-185-5p was able to target and down-regulate the HDGF expression. CONCLUSION Knocking down CircRAD18 can reduce HDGF expression by up-regulating miR-185-5p, thereby weakening DNR resistance in AML cells, inhibiting KG1a cell proliferation under DNR treatment, and promoting apoptosis.
Humans ; MicroRNAs/metabolism* ; Leukemia, Myeloid, Acute ; Daunorubicin/pharmacology* ; Drug Resistance, Neoplasm ; Apoptosis ; RNA, Circular ; Intercellular Signaling Peptides and Proteins/metabolism* ; Cell Proliferation ; HL-60 Cells ; Cell Line, Tumor

OBJECTIVE: To investigate the regulatory effect of Wip1 phosphatase on hematopoietic function in the mouse spleen. METHODS: Wip1 knockout mice were bred, and the effect of Wip1 deletion on the proportion and number of hematopoietic stem/progenitor cells, as well as their mature subsets in mouse spleen was detected by flow cytometry. The Proteome Profiler^TM antibody array was used to analyze the role of Wip1 deletion on the expression of inflammatory cytokines in CD45^highCD11b⁺ myeloid cells sorted from mouse spleen. RESULTS: Wip1 deletion resulted in smaller size and significant reduction of cell number in the mouse spleen. The absolute numbers of hematopoietic stem/progenitor cells were decreased. Meanwhile, the absolute number of T and B lymphocytes also significantly declined. However, the proportion of erythroid progenitors and erythroid cells at various stage significantly increased, but the number of mature erythroid cells decreased. Furthermore, the myeloid cells and their subsets neutrophils, monocytes, CD45^highCD11b⁺ and CD45^lowCD11b⁺ were all reduced. CD45^highCD11b⁺ myeloid cells displayed proinflammatory phenotype in the spleen. CONCLUSION Wip1 gene deletion impairs normal hematopoietic function in the mouse spleen, leading to a significant reduction of mature hematopoietic cells of various lineages, and proinflammatory phenotype in CD45^highCD11b⁺ myeloid cells.
Animals ; Mice ; Spleen/cytology* ; Mice, Knockout ; Hematopoietic Stem Cells/cytology* ; Myeloid Cells/cytology* ; Protein Phosphatase 2C ; Hematopoiesis ; Flow Cytometry

OBJECTIVES: Acute lung injury (ALI) is an acute respiratory failure syndrome characterized by impaired gas exchange. Due to the lack of effective targeted drugs, it is associated with high mortality and poor prognosis. Tripterygium wilfordii (TW) has demonstrated anti-inflammatory activity in the treatment of various diseases. This study aims to investigate the effects and underlying mechanisms of TW on myeloid-derived suppressor cells (MDSCs) in ALI, providing experimental evidence for TW as a potential adjuvant therapy for ALI. METHODS: Eighteen specific pathogen-free (SPF) C57BL/6 mice were randomly divided into normal control (NC; intranasal saline), lipopolysaccharide (LPS; 5 mg/kg intranasally to induce ALI), and LPS+TW (50 mg/kg TW by gavage on the first day of modeling, followed by 5 mg/kg LPS intranasally to induce ALI) groups (n=6 each). Lung injury and edema were assessed by histopathological scoring and wet-to-dry weight ratio. Cytokine levels [interleukin (IL)-1β, IL-6, IL-18, tumor necrosis factor-α (TNF-α)] in lung tissue lavage fluid were measured by enzyme-linked immunosorbent assay (ELISA). Flow cytometry was used to assess the proportions of MDSCs, polymorphonuclear MDSCs (PMN-MDSCs), and monocytic MDSCs (M-MDSCs) in bone marrow, spleen, peripheral blood, and lung tissue, as well as reactive oxygen species (ROS) levels in lung tissues. Messenger RNA (mRNA) expression levels of inducible nitric oxide synthase (iNOS) and arginase-1 (ARG-1) in lung tissues were determined by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR). PMN-MDSCs sorted from the lungs of LPS-treated mice were co-cultured with splenic CD3⁺ T cells and divided into NC, triptolide (TPL)-L, and TPL-H groups, with bovine serum albumin, 25 nmol/L TPL, and 50 nmol/L TPL, respectively. Flow cytometry was used to detect the effect of PMN-MDSCs on T-cell proliferation, and RT-qPCR was used to measure iNOS and ARG-1 mRNA expression. RESULTS: Compared with the NC group, the LPS group showed marked lung pathology with significantly increased histopathological scores and wet-to-dry ratios (both P<0.001). TW treatment significantly alleviated lung injury and reduced both indices compared with the LPS group (both P<0.05). Cytokine levels were significantly decreased in the LPS+TW group compared with the LPS group (all P<0.001). The proportions of MDSCs in CD45⁺ cells from spleen, bone marrow, peripheral blood, and lung, as well as PMN-MDSCs from spleen, peripheral blood, and lung, were significantly reduced in the LPS+TW group compared with the LPS group (all P<0.05), accompanied by reduced ROS levels in lung tissues (P<0.001). iNOS and ARG-1 mRNA expression in lung tissues was significantly lower in the LPS+TW group than in the LPS group (both P<0.001). In vitro, compared with the TPL-L group, the TPL-H group showed significantly increased CD3⁺ T-cell proliferation (P<0.001), and decreased iNOS and ARG-1 mRNA expression (all P<0.05). CONCLUSIONS TW alleviates the progression of LPS-induced ALI in mice, potentially by reducing the proportion of MDSCs in lung tissues and attenuating the immunosuppressive function of PMN-MDSCs.
Animals ; Acute Lung Injury/chemically induced* ; Myeloid-Derived Suppressor Cells/cytology* ; Tripterygium/chemistry* ; Mice, Inbred C57BL ; Mice ; Cell Differentiation/drug effects* ; Male ; Lipopolysaccharides ; Nitric Oxide Synthase Type II/genetics* ; Cytokines/metabolism* ; Reactive Oxygen Species/metabolism* ; Diterpenes/pharmacology* ; Epoxy Compounds ; Phenanthrenes

OBJECTIVES: To investigate the role of METTL3 and FOXO3 in anthracycline resistance in acute myeloid leukemia (AML) cells. METHODS: Methylated RNA immunoprecipitation sequencing (MeRIP-seq) and transcriptome sequencing (RNA-seq) were performed in anthracycline-resistant and sensitive HL60 and K562 cells with lentivirus-mediated knockdown or overexpression of METTL3 and FOXO3. TCGA and GSE6891 datasets were used for analysis of the clinical and gene expression data of AMI patients. FOXO3 expressions at the mRNA and protein levels in the transfected cells were detected with RT-qPCR and Western blotting, and the changes in cell proliferation and apoptosis were evaluated using CCK8 assay and flow cytometry; the expression of m⁶A-modified mRNA and mRNA stability of FOXO3 was detected analyzed using MeRIP-qPCR and RT-qPCR. Functional enrichment analysis of the differential genes in the transfected cells was performed. RESULTS: Differential gene analysis in anthracycline-resistant versus sensitive AML cells and in cells with METTL3 knockdown revealed the enrichment in FoxO and autophagy pathways (P<0.05), and the anthracycline-resistant cells showed significantly increased m⁶A modification of FOXO3. FOXO3 expression was positively correlated with METTL3 expression. METTL3 knockdown significantly reduced FOXO3 mRNA stability and its protein levels in anthracycline-resistant AML cells, which exhibited higher m6A-modified FOXO3 expression levels than their sensitive counterparts. Database analysis, Kaplan-Meier analysis and RT-qPCR results suggested that a high FOXO3 expression was associated with a poor prognosis of AML patients. In anthracycline-resistant AML cells expressing higher FOXO3 levels than the sensitive cells, lentivirus-mediated overexpression of FOXO3 significantly enhanced cell proliferation and suppressed cell apoptosis. Inhibiting autophagy using an autophagy inhibitor (Baf.A1) obviously enhanced the inhibitory effect of adriamycin on resistant AMI cells and cells overexpressing FOXO3. CONCLUSIONS METTL3 promotes FOXO3 expression via m6A modification, and FOXO3-driven autophagy contributes to anthracycline resistance in AML cells by enhancing cell proliferation and suppressing cell apoptosis.
Humans ; Forkhead Box Protein O3/genetics* ; Leukemia, Myeloid, Acute/genetics* ; Drug Resistance, Neoplasm ; Methyltransferases/genetics* ; Autophagy ; Anthracyclines/pharmacology* ; HL-60 Cells ; Apoptosis ; Cell Proliferation ; K562 Cells

OBJECTIVES: To explore the key role of myeloid-derived suppressive cells (MDSCs) in pre-metastatic niche (PMN) and analyze their interrelationships with the main components in the microenvironment using a mathematical model. METHODS: Mathematical descriptions were used to systematically analyze the functions of MDSCs in tumor metastasis and elucidate their association with the major components (vascular endothelial cells, mesenchymal stromal cells, and cancer-associated macrophages) contributing to the formation of the pre-metastatic microenvironment. Based on the formation principle of the pre-metastatic microenvironment of tumors, the key biological processes were assumed to construct a coupled partial differential diffusion equation model. The existence and uniqueness of the model solutions were investigated using approximation methods, the qualitative theory of partial differential equations and Banach's immovable point theorem, and numerical simulations were carried out by differential numerical methods to verify the reliability and accuracy of the model. RESULTS: The existence and uniqueness of the local and overall solutions of the model were proved using the approximation method, the qualitative theory of partial differential equations and Banach's immovable point theorem in combination with the regularity estimation of the local solutions and the embedding inequality. Numerical simulation results further validated the reliability of the model and demonstrated the important role of MDSCs in the pre-metastatic microenvironment of tumors, especially in angiogenesis and immunosuppression. CONCLUSIONS This study reveals the important functions of MDSCs in the pre-metastatic microenvironment of tumors through mathematical modeling and numerical simulation, which provides an important theoretical basis for understanding the mechanism of tumor metastasis and devising cancer treatment strategies.
Tumor Microenvironment ; Myeloid-Derived Suppressor Cells ; Neoplasm Metastasis ; Humans ; Models, Biological ; Models, Theoretical ; Neoplasms/pathology*

OBJECTIVES: To investigate the effect of hypaphorine (HYP) on Crohn's disease (CD)‑like colitis in mice and its molecular mechanism. METHODS: Thirty male C57BL/6J mice were equally randomized into WT, TNBS, and HYP groups, and in the latter two groups, mouse models of CD-like colitis were established using TNBS with daily gavage of 15 mg/kg HYP or an equivalent volume of saline. The treatment efficacy was evaluated by assessing the disease activity index (DAI), body weight changes, colon length and histopathology. The effect of HYP was also tested in a LPS-stimulated Caco-2 cell model mimicking intestinal inflammation by evaluating inflammatory responses and barrier function of the cells using qRT-PCR and immunofluorescence staining. GO and KEGG analyses were conducted to explore the therapeutic mechanism of HYP, which was validated in both the cell and mouse models using Western blotting. RESULTS: In the mouse models of CD-like colitis, HYP intervention obviously alleviated colitis as shown by significantly reduced body weight loss, colon shortening, DAI and inflammation scores, and expressions of pro-inflammatory factors in the colon tissues. HYP treatment also significantly increased the TEER values, reduced bacterial translocation to the mesenteric lymph nodes, liver, and spleen, lowered serum levels of I-FABP and FITC-dextran, increased the number of colonic tissue cup cells, and upregulated colonic expressions of MUC2 and tight junction proteins (claudin-1 and ZO-1) in the mouse models. In LPS-stimulated Caco-2 cells, HYP treatment significantly inhibited the expressions of pro-inflammatory factors and increased the expressions of tight junction proteins. Western blotting showed that HYP downregulated the expressions of the key proteins in the TLR4/MyD88 signaling pathway in both the in vitro and in vivo models. CONCLUSIONS HYP alleviates CD-like colitis in mice possibly by suppressing intestinal epithelial inflammation and improving gut barrier function.
Animals ; Male ; Mice, Inbred C57BL ; Crohn Disease/drug therapy* ; Mice ; Humans ; Caco-2 Cells ; Intestinal Mucosa/metabolism* ; Colitis/drug therapy* ; Disease Models, Animal ; Inflammation ; Toll-Like Receptor 4/metabolism* ; Myeloid Differentiation Factor 88/metabolism* ; Intestinal Barrier Function

Cancer is the result of evolving crosstalk between neoplastic cell and its immune microenvironment. In recent years, immune therapeutics targeting T lymphocytes, such as immune checkpoint blockade (ICB) and CAR-T, have made significant progress in cancer treatment and validated targeting immune cells as a promising approach to fight human cancers. However, responsiveness to the current immune therapeutic agents is limited to only a small proportion of solid cancer patients. As major components of most solid tumors, myeloid cells played critical roles in regulating the initiation and sustentation of adaptive immunity, thus determining tumor progression as well as therapeutic responses. In this review, we discuss emerging data on the diverse functions of myeloid cells in tumor progression through their direct effects or interactions with other immune cells. We explain how different metabolic reprogramming impacts the characteristics and functions of tumor myeloid cells, and discuss recent progress in revealing different mechanisms-chemotaxis, proliferation, survival, and alternative sources-involved in the infiltration and accumulation of myeloid cells within tumors. Further understanding of the function and regulation of myeloid cells is important for the development of novel strategies for therapeutic exploitation in cancer.
Humans ; Tumor Microenvironment/immunology* ; Myeloid Cells/immunology* ; Neoplasms/therapy* ; Animals

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*