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

Objective To explore the effect of miR-582-5p on Mycobacterium tuberculosis (Mtb)-infected macrophages by regulating dual specificity phosphatase 1 (DUSP1). Methods THP-1 macrophages were divided into six groups: control group, Mtb group, inhibitor-NC group, miR-582-5p inhibitor group, miR-582-5p inhibitor+si-NC group, and miR-582-5p inhibitor+si-DUSP1 group. QRT-PCR was applied to detect the gene expression of miR-582-5p and DUSP1 in cells. ELISA kit was used to detect the levels of interferon γ (IFN-γ), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), and interleukin 1β (IL-1β). CCK-8 method was applied to detect cell proliferation. Flow cytometry was applied to detect cell apoptosis rate. Western blot analysis was used to measure the protein expression levels of B-cell lymphoma 2 (Bcl2), Bcl2-associated X (BAX), and cleaved-caspase 3 (c-caspase-3) in cells. In addition, the target relationship between miR-582-5p and DUSP1 was verified. Results Compared with the control group, the expression of miR-582-5p, levels of IFN-γ, IL-6, TNF-α, IL-1β, bacterial load and OD450 values (24 h, 48 h), and the protein expression of Bcl2 in macrophages were higher in the Mtb group, while the mRNA expression of DUSP1, apoptosis rate, and the protein expression levels of c-caspase-3, BAX and DUSP1 were lower. Compared with the Mtb group and the inhibitor-NC group, the above-mentioned indicators in the miR-582-5p inhibitor group were partially reversed. Down-regulation of DUSP1 expression partially reversed the inhibitory effect of down-regulation of miR-582-5p expression on Mtb-infected macrophages. Conclusion Inhibiting the expression of miR-582-5p can up-regulate DUSP1, thereby inhibiting the proliferation and inflammatory response of Mtb-infected macrophages and promoting cell apoptosis.
Humans ; Macrophages/metabolism* ; Dual Specificity Phosphatase 1/metabolism* ; MicroRNAs/metabolism* ; Mycobacterium tuberculosis/physiology* ; Tuberculosis/microbiology* ; Apoptosis/genetics* ; THP-1 Cells ; Cell Proliferation/genetics* ; Interferon-gamma/genetics* ; Tumor Necrosis Factor-alpha/genetics* ; Interleukin-1beta/genetics*

Objective To investigate the effects of hyaluronic acid and proteoglycan-linked protein 1 (HAPLN1) secreted by synovial fibroblasts (FLS) on the polarization of macrophages (Mϕ) in rheumatoid arthritis (RA). Methods Human monocytic leukemia cells (THP-1) were differentiated into Mϕ, which were subsequently exposed to recombinant HAPLN1 (rHAPLN1). RA-FLS were transfected separately with HAPLN1 overexpression plasmid (HAPLN1^OE) or small interfering RNA targeting HAPLN1 (si-HAPLN1), and then co-cultured with Mϕ to establish a co-culture model. The viability of Mϕ was assessed using the CCK-8 assay, and the proportions of pro-inflammatory M1-type and anti-inflammatory M2-type Mϕ were analyzed by flow cytometry. Additionally, the expression levels of inflammatory markers, including interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α), and inducible nitric oxide synthase (iNOS), were quantified using quantitative real-time PCR and Western blot analysis. Results The viability of Mϕ was increased in the rHAPLN1 group compared to the control group. Furthermore, both the M1/Mϕ ratio and inflammatory factor levels were elevated in the rHAPLN1 and HAPLN1^OE groups. In contrast, the si-HAPLN1 group exhibited a decrease in the M1/Mϕ ratio and inflammatory factor expression. Notably, the introduction of rHAPLN1 in rescue experiments further promoted Mϕ polarization towards the M1 phenotype. Conclusion HAPLN1, secreted by RA fibroblast-like synoviocytes (RA-FLS), enhances Mϕ polarization towards the M1 phenotype.
Humans ; Arthritis, Rheumatoid/genetics* ; Macrophages/immunology* ; Fibroblasts/metabolism* ; Phenotype ; Extracellular Matrix Proteins/genetics* ; Proteoglycans/genetics* ; Synovial Membrane/cytology* ; Tumor Necrosis Factor-alpha/genetics* ; Interleukin-1beta/genetics* ; Nitric Oxide Synthase Type II/genetics* ; Cell Differentiation ; Coculture Techniques ; THP-1 Cells

Objectives To investigate interleukin 36γ (IL-36γ) expression, and analyze the influence of IL-36γ to CD8⁺ T cell activity in chronic obstructive pulmonary diseases (COPD) patients with secondary fungal pneumonia. Methods Peripheral blood was collected from 47 COPD patients, 39 COPD patients with secondary fungal pneumonia, and 20 controls. Bronchial alveolar lavage fluid (BALF) was isolated from 27 COPD patients with secondary fungal pneumonia. CD8⁺ T cells were purified. The levels of four IL-36 isoforms in plasma and BALF were measured by enzyme linked immunosorbent assay (ELISA). CD8⁺ T cells were stimulated with recombinant human IL-36γ. The levels of interferon γ(IFN-γ), tumor necrosis factor α(TNF-α), perforin and granzyme B in the cultured supernatants were measured by ELISA. Recombinant human IL-36γ-stimulated CD8⁺ T cells were co-cultured with NCI-H1882 cells in either direct cell-to-cell contact or Transwell^TM manner. The levels of IFN-γ, TNF-α, and lactate dehydrogenase in the cultured supernatants were assessed. The percentage of target cell death was calculated. Results Plasma IL-36α, IL-36β, and IL-36γ levels were significantly elevated in both COPD group and COPD with secondary fungal pneumonia group compared with those in control group. However, only plasma IL-36γ level was higher in COPD with secondary fungal pneumonia group than that in COPD group [(200.11±99.95)pg/mL vs (53.03±87.18)pg/mL, P=0.023]. There was no remarkable difference in plasma IL-36 receptor antagonist level among three groups. IL-36γ level in BALF from infectious site was higher than that from non-infectious site in COPD with secondary fungal pneumonia group [(305.82±59.60)pg/mL vs (251.93±76.01)pg/mL, P=0.011]. IL-36γ stimulation enhanced IFN-γ, TNF-α, perforin and granzyme B secreted by CD8⁺ T cells. When IL-36γ-stimulated CD8⁺ T cells were directly mixed with NCI-H1882 cells for co-culture, the percentage of cell death was increased [(16.06±3.67)% vs (11.47±2.36)%, P=0.002]. When using Transwell^TM plate for non-contact co-culture, IL-36γ-stimulated CD8⁺ T cell-mediated death of NCI-H1882 cells showed no significant difference compared to that without stimulation [(4.77±0.78)% vs (4.99±0.92)%, P=0.554]. Conclusion IL-36γ level in plasma and infectious site is elevated in COPD patients with secondary fungal pneumonia, which enhances the cytotoxicity of CD8⁺ T cells in peripheral blood and infectious microenviroment.
Humans ; Pulmonary Disease, Chronic Obstructive/complications* ; CD8-Positive T-Lymphocytes/metabolism* ; Male ; Female ; Aged ; Middle Aged ; Interferon-gamma/metabolism* ; Interleukin-1/metabolism* ; Tumor Necrosis Factor-alpha/metabolism* ; Lung Diseases, Fungal/complications* ; Bronchoalveolar Lavage Fluid/chemistry* ; Perforin/metabolism* ; Pneumonia/immunology* ; Granzymes/metabolism*

OBJECTIVES: To investigate the effect of Shenge powder (SGP) on myocardial fibrosis in rats with heart failure after myocardial infarction and its relation with lysyl oxidase like protein 2 (LOXL2)/transforming growth factor-β1 (TGF-β1)/IL-11 signaling pathway. METHODS: Seventy-two SPF male SD rats were divided into blank control group, model control group, SGP small dose group, SGP large dose group, positive control group, SGP large dose+LOXL2 activator group, with 12 rats in each group. Except for the blank control group, post-myocardial infarction heart failure was induced by coronary constriction. Corresponding treatments were given immediately after successful modeling, once a day for 4 weeks. Left ventricular fractional shortening (LVFS) and left ventricular ejection fraction (LVEF) in rats were detected by color Doppler ultrasound imaging. Levels of IL-1β and IL-6 in serum were analyzed by ELISA method. Myocardial collagen volume fraction (CVF) was evaluated by Masson staining. Expressions of collagen Ⅰ and α-smooth muscle actin (α-SMA) in myocardial tissue were detected by immunohistochemical staining. The mRNA expressions of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1) in myocardial tissue were detected by qRT-PCR. Expression of LOXL2, TGF-β1, and IL-11 proteins in myocardial tissue were detected by Western blotting. RESULTS: Compared with the blank control group, the LVFS and LVEF of the model control group decreased, the levels of serum IL-6 and IL-1β elevated, and the CVF value, the expressions of collagen Ⅰ and α-SMA in myocardial tissue, MMP-9 and TIMP-1 mRNA, and LOXL2, TGF-β1, IL-11 proteins increased (all P<0.05). Compared with the model control group, the LVFS and LVEF of SGP small dose group, SGP large dose group and positive control group increased, the levels of serum IL-6 and IL-1β decreased, and the CVF value, the expressions of collagen Ⅰ and α-SMA in myocardial tissue, MMP-9 and TIMP-1 mRNA, and LOXL2, TGF-β1, IL-11 proteins decreased (all P<0.05); while LOXL2 activator reversed the improvement effect of high-dose SGP on myocardial fibrosis in heart failure rats after myocardial infarction. CONCLUSIONS Shenge powder may inhibit myocardial fibrosis in heart failure rats after myocardial infarction by inhibiting the LOXL2/TGF-β1/IL-11 pathway.
Animals ; Male ; Rats, Sprague-Dawley ; Myocardial Infarction/complications* ; Transforming Growth Factor beta1/metabolism* ; Signal Transduction/drug effects* ; Drugs, Chinese Herbal/therapeutic use* ; Rats ; Heart Failure/pathology* ; Myocardium/metabolism* ; Fibrosis ; Amino Acid Oxidoreductases/metabolism* ; Interleukin-11/metabolism* ; Tissue Inhibitor of Metalloproteinase-1/metabolism* ; Matrix Metalloproteinase 9/metabolism*

OBJECTIVES: To explore the protective effect of vitexin-4 ″-O-glucoside (VOG) against acetaminophen-induced acute liver injury in mice and its underlying mechanism. METHODS: C57BL/6 mice were randomly divided into 4 groups: normal control group, model control group, low-dose group of VOG (30 mg/kg), and high-dose group of VOG (60 mg/kg). Acute liver injury was induced by intraperitoneal injection of acetaminophen (500 mg/kg). VOG was administrated by gavage 2 h before acetaminophen treatment in VOG groups. The protective effect of VOG against acute liver injury was evaluated by detecting alanine transaminase (ALT), aspartate transaminase (AST) levels and hematoxylin and eosin staining. The malondialdehyde (MDA) content, superoxide dismutase (SOD) and catalase (CAT) activity in liver were detected to evaluate the hepatic oxidative stress. The expression levels of tumor necrosis factor (TNF)-α, Il-1β, and Il-6 in liver were detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR). The expression levels of phosphorylated c-jun N-terminal kinase (JNK)/JNK, phosphorylated p38/p38, inositol-requiring enzyme 1 alpha (IRE-1α), X-box binding protein 1s (XBP1s), and glucose-regulated protein 78 (GRP78) in liver were detected by Western blotting. An endoplasmic reticulum stress model was established in AML-12 cells using tunicamycin. Cell viability was assessed using the CCK-8 assay, and the degree of cell damage was detected by lactate dehydrogenase (LDH) assay. The gene expression levels of Ire-1α, Xbp1s, and Grp78 in the cells were detected using qRT-PCR. RESULTS: In the animal experiments, compared with the model control group, VOG significantly improved plasma ALT and AST levels, liver MDA content, as well as SOD and CAT activities. VOG also reduced the expression levels of Tnf-α, Il-1β, and Il-6 in the liver, and improved protein phosphorylation levels of JNK and p38, as well as the protein expression levels of IRE-1α, XBP1s, and GRP78. In cell experiments, VOG pretreatment enhanced cell viability, reduced LDH release and decreased the mRNA expression of Ire-1α, Xbp1s, and Grp78. CONCLUSIONS VOG can suppress inflammation and oxidative stress, and alleviate acetaminophen-induced acute liver injury in mice by suppressing endoplasmic reticulum stress and modulating the MAPK signaling pathway.
Animals ; Endoplasmic Reticulum Chaperone BiP ; Mice ; Acetaminophen/adverse effects* ; Mice, Inbred C57BL ; Chemical and Drug Induced Liver Injury/prevention & control* ; Glucosides/therapeutic use* ; Oxidative Stress/drug effects* ; Male ; Apigenin/therapeutic use* ; Liver/drug effects* ; Tumor Necrosis Factor-alpha/metabolism* ; Endoplasmic Reticulum Stress/drug effects* ; X-Box Binding Protein 1 ; Endoribonucleases/metabolism* ; Interleukin-1beta/metabolism* ; Interleukin-6/metabolism* ; Protein Serine-Threonine Kinases

OBJECTIVE: To explore the expression and clinical significance of programmed death receptor 1 (PD-1), Th1, Th2, and Th17 cytokines in multiple myeloma (MM). METHODS: A total of 76 MM patients treated in the Tengzhou Central People's Hospital from May 2021 to May 2023 were collected as MM group, and 48 healthy individuals who underwent physical examination during the same period were included as control group. The expression of PD-1 on the surface of CD4⁺ and CD8⁺ T cells and the levels of serum Th1 cytokines ［interleukin (IL) -2, interferon γ (IFN-γ), tumor necrosis factor α (TNF-α)］, Th2 cytokines (IL-4, IL-6, IL-10) and Th17 cytokines (IL-17) were detected in the two groups. Spearman correlation was used to examine the relationship between PD-1, Th1, Th2 and Th17 cytokines and clinical stage and immune typing of MM patients. Multivariate logistic regression analysis was used to analyze the related factors affecting the efficacy of chemotherapy in MM patients, and the factors were tested for multicollinearity. Receiver operating characteristic (ROC) curve was drawn to analyze the predictive value of PD-1, Th1, Th2 and Th17 cytokines in chemotherapy efficacy of MM patients. RESULTS: The levels of CD4⁺T PD-1, CD8⁺T PD-1, IL-4, IL-6, IL-10, and IL-17 in the MM group were higher than those in the control group, while the levels of IL-2, IFN-γ, and TNF-α were lower (all P <0.001). The levels of CD4⁺T PD-1, CD8⁺T PD-1, IL-4, IL-6, IL-10, and IL-17 in R-ISS stage III patients were higher than those in stage II and I patients, and the levels in stage II patients were higher than those in stage I patients (all P <0.05). The IL-2 level in R-ISS stage III patients was lower than that in stage II and I patients, and IL-2 level in R-ISS stage II patients was lower than that in stage I patients (all P <0.05). The levels of CD4⁺T PD-1, CD8⁺T PD-1, IL-4, IL-6, IL-10, and IL-17 in IgG patients were higher than those in IgA, light chain, and non secretory patients, while the level of IL-2 was lower (all P <0.05). Correlation analysis showed that CD4⁺T PD-1, CD8⁺T PD-1, IL-4, IL-6, IL-10, and IL-17 were positively correlated with R-ISS staging in MM patients (r =0.623, 0.635, 0.728, 0.330, 0.742, 0.412), and negatively correlated with immune classification (r =-0.664, -0.756, -0.642, -0.479, -0.613, -0.323). IL-2 was negatively correlated with R-ISS staging in MM patients (r =-0.280), and positively correlated with immune classification (r =0.483). The levels of CD4⁺T PD-1, CD8⁺T PD-1, IL-4, IL-6, IL-10, and IL-17 in the non-remission group were higher than those in the remission group, while the level of IL-2 was lower (all P <0.001). Multivariate logistic regression analysis showed that the increased CD4⁺T PD-1, CD8⁺T PD-1, IL-4, IL-6, IL-10 and IL-17 were risk factors for the efficacy of chemotherapy in MM patients (OR >1, P <0.05), while the increased IL-2 was a protective factor (OR < 1, P <0.05). The results of multicollinearity test showed that the tolerance of the seven factors included was between 0.714-0.885, and the variance inflation factor was between 1.130-1.400. There was no multicollinearity. The ROC curve analysis results showed that the area under the curve for the combined prediction of chemotherapy efficacy in MM patients by the above 7 factors was 0.942, with specificity of 0.741 and sensitivity of 0.909. CONCLUSION The expression levels of PD-1 on the surface of CD4⁺ and CD8⁺ T cells and serum Th2 and Th17 cytokines in MM patients are high, while Th1 cytokines are low. PD-1, Th1, Th2, and Th17 cytokines are related to clinical stage and immune classification of MM patients. The combined detection of these indicators can help predict the chemotherapy efficacy of MM patients.
Humans ; Programmed Cell Death 1 Receptor/metabolism* ; Multiple Myeloma/blood* ; Cytokines/metabolism* ; Th17 Cells/metabolism* ; Th1 Cells/metabolism* ; Th2 Cells/metabolism* ; Female ; Male ; Interleukin-10 ; Interferon-gamma ; Middle Aged ; Interleukin-17 ; Interleukin-2 ; Interleukin-4 ; Tumor Necrosis Factor-alpha ; Interleukin-6 ; Aged

OBJECTIVE: To investigate the role of MK2 inhibitor MMI-0100 on inflammatory response after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and related mechanisms. METHODS: An allo-HSCT mouse model was established. Recipient rats were randomly divided into BMT+NaCl group and BMT+MMI-0100 group, and were injected with NaCl and MMI-0100 every day after transplantation, respectively. Samples of the two groups were collected on d 7 and 14, femur paraffin sections were stained with HE, and pathological changes in the bone marrow cavity were observed under the light microscope. The gene and protein expression levels of pro-inflammatory cytokines IL-1β and IL-18 were detected by qPCR and Western blot. Macrophage typing was detected by flow cytometry. The expression levels of NLRP3 and Caspase-1 were detected by Western blot. RESULTS: Inflammatory cell infiltration in the bone marrow cavity was significantly reduced in the BMT+MMI-0100 group. Western blot results showed that the protein expression levels of IL-1β and IL-18 in the BMT+MMI-0100 group were decreased compared to the BMT+NaCl group on day 7 and day 14 (all P <0.01). The qPCR results showed that compared to the BMT+NaCl group, the IL-18 gene expression levels in the BMT+MMI-0100 group were significantly reduced on day 7 and day 14 (both P <0.01). In the BMT+MMI-0100 group, the expression level of IL-1β gene decreased on day 7 (P <0.05), but increased and was higher than that in the BMT+NaCl group on day 14 (P <0.05). Flow cytometry results showed that the expression of M1 macrophages and M1/M2 ratio decreased in the BMT+MMI-0100 group compared to BMT+NaCl group (all P <0.05). Western blot results showed that the protein expression levels of NLRP3 and Caspase-1 in the BMT+MMI-0100 group were lower than those in the BMT+NaCl group (all P <0.05). CONCLUSION MMI-0100 can ameliorate bone marrow inflammatory injury after allo-HSCT and may act by reducing NLRP3 expression to promote M2 polarization.
Animals ; Interleukin-1beta/metabolism* ; Rats ; Interleukin-18/metabolism* ; Hematopoietic Stem Cell Transplantation/adverse effects* ; Mice ; NLR Family, Pyrin Domain-Containing 3 Protein/metabolism* ; Inflammation ; Bone Marrow/pathology* ; Protein Serine-Threonine Kinases/metabolism* ; Intracellular Signaling Peptides and Proteins/antagonists & inhibitors* ; Caspase 1/metabolism* ; Macrophages ; Transplantation, Homologous

BACKGROUND: Asthma is a common chronic inflammatory airway disease and intermittent hypoxia is increasingly recognized as a factor that may impact disease progression. The present study investigated whether intermittent hypoxia (IH) could aggravate asthma by promoting hypoxia-inducible factor-1α (HIF-1α)/nucleotide-binding oligomerization domain (NOD)-like receptor pyrin domain-containing protein 3 (NLRP3)/interleukin (IL)-1β-dependent pyroptosis and the inflammatory response and further elucidated the underlying molecular mechanisms involved. METHODS: A total of 49 patients diagnosed with severe bronchial asthma and diagnosed by polysomnography were enrolled at Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, between January 2022 and December 2022, and their general data and induced sputum were collected. BEAS-2B cells were treated with IL-13 and subjected to IH. An ovalbumin (OVA)-treated mouse model was also used to assess the effects of chronic intermittent hypoxia (CIH) on asthma. Pyroptosis, the inflammatory response, and related signalling pathways were assessed in vivo and in vitro . RESULTS: In this study, as the apnoea and hypopnea index (AHI) increased, the proportion of patients with uncontrolled asthma increased. The proportions of neutrophils and the levels of IL-6, IL-8, HIF-1α and NLRP3 in induced sputum were related to the AHI. NLRP3-mediated pyroptosis, which could be mediated by the HIF-1α signalling pathway, was activated in IL-13 plus IH-treated BEAS-2B cells and in the lungs of OVA/CIH mice. HIF-1α downregulation significantly reduced lung pyroptosis and ameliorated neutrophil inflammation by modulating the NLRP3/IL-1β pathway both in vitro and in vivo . Similarly, pretreatment with LW6, an inhibitor of HIF-1α, effectively blocked the generation of inflammatory cytokines in neutrophils. In addition, administration of the NLRP3 activator nigericin obviously increased lung neutrophil inflammation. CONCLUSIONS Obstructive sleep apnoea-hypopnea syndrome (OSAHS) is a risk factor for asthma exacerbation. IH aggravates neutrophil inflammation in asthma via NLRP3/IL-1β-dependent pyroptosis mediated by the HIF-1α signalling pathway, which should be considered a potential therapeutic target for the treatment of asthma with OSAHS.
NLR Family, Pyrin Domain-Containing 3 Protein/metabolism* ; Humans ; Asthma/metabolism* ; Animals ; Pyroptosis/physiology* ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism* ; Mice ; Signal Transduction/physiology* ; Male ; Hypoxia/metabolism* ; Female ; Interleukin-1beta/metabolism* ; Adult ; Inflammation/metabolism* ; Middle Aged ; Mice, Inbred C57BL

This study investigated the regulatory potential of salidroside (SAL), a primary active compound in Rhodiola rosea L., on osteoclast differentiation by modulating the hypoxia-inducible factor 1-alpha (HIF-1a) pathway in osteoblasts. Luciferase reporter assay and chromatin immunoprecipitation (ChIP) assay were employed to validate whether the receptor activator of nuclear factor-?B ligand (RANKL) is the downstream target gene of HIF-1a in osteoblasts. The study also utilized lipopolysaccharide (LPS)-induced mouse osteolysis to examine the impact of SAL on osteolysis in vivo. Furthermore, conditioned medium (CM) from SAL-pretreated osteoblasts was used to investigate the paracrine effects on osteoclastogenesis through the HIF-1a pathway. Hypoxic condition-induced overexpression of HIF-1a upregulated RANKL levels by binding to the RANKL promoter and enhancing transcription in osteoblastic cells. In vivo, SAL significantly alleviated bone tissue hypoxia and decreased the expression of HIF-1a by downregulating the expression of RANKL, vascular endothelial growth factor (VEGF), interleukin 6 (IL-6), and angiopoietin-like 4 (ANGPTL4). In the paracrine experiment, conditioned media from SAL-pretreated osteoblasts inhibited differentiation through the HIF-1a/RANKL, VEGF, IL-6, and ANGPTL4 pathways. RANKL emerges as the downstream target gene regulated by HIF-1a in osteoblasts. SAL significantly alleviates bone tissue hypoxia and bone loss in LPS-induced osteolysis through the HIF-1a/RANKL, VEGF, IL-6, and ANGPTL4 pathways. SAL inhibits osteoclast differentiation by regulating osteoblast paracrine secretion.
Animals ; Osteoblasts/cytology* ; Hypoxia-Inducible Factor 1, alpha Subunit/genetics* ; Glucosides/administration & dosage* ; Cell Differentiation/drug effects* ; Phenols/administration & dosage* ; Mice ; Osteoclasts/metabolism* ; RANK Ligand/genetics* ; Rhodiola/chemistry* ; Osteogenesis/drug effects* ; Signal Transduction/drug effects* ; Interleukin-6/genetics* ; Male ; RAW 264.7 Cells ; Osteolysis/genetics* ; Humans ; Mice, Inbred C57BL