Neuronal Death Caused by HMGB1-Evoked via Inflammasomes from Thrombin-Activated Microglia Cells.

Microglial cells are a macrophage-like cell type residing within the CNS. These cells evoke pro-inflammatory responses following thrombin-induced brain damage. Inflammasomes, which are large caspase-1-activating protein complexes, play a critical role in mediating the extracellular release of HMGB1 in activated immune cells. The exact role of inflammasomes in microglia activated by thrombin remains unclear, particularly as it relates to the downstream functions of HMGB1. After receiving microinjections of thrombin, Sprague Dawley rats of 200 to 250 gm were studied in terms of behaviors and immunohistochemical staining. Primary culture of microglia cells and BV-2 cells were used for the assessment of signal pathways. In a water maze test and novel object recognition analysis, microinjections of thrombin impaired rats' short-term and long-term memory, and such detrimental effects were alleviated by injecting anti-HMGB-1 antibodies. After thrombin microinjections, the increased oxidative stress of neurons was aggravated by HMGB1 injections but attenuated by anti-HMGB-1 antibodies. Such responses occurred in parallel with the volume of activated microglia cells, as well as their expressions of HMGB-1, IL-1ß, IL-18, and caspase-I. In primary microglia cells and BV-2 cell lines, thrombin also induced NO release and mRNA expressions of iNOS, IL-1ß, IL-18, and activated caspase-I. HMGB-1 aggravated these responses, which were abolished by anti-HMGB-1 antibodies. In conclusion, thrombin induced microglia activation through triggering inflammasomes to release HMGB1, contributing to neuronal death. Such an action was counteracted by the anti-HMGB-1 antibodies. The refinement of HMGB-1 modulated the neuro-inflammatory response, which was attenuated in thrombin-associated neurodegenerative disorder.

Downregulation of miR-26b attenuates early brain injury induced by subarachnoid hemorrhage via mediating the KLF4/STAT3/HMGB1 axis.

BACKGROUND: Early brain injury (EBI) refers to early-onset secondary complications that occur after subarachnoid hemorrhage (SAH), and associated with high rate of disability and mortality. Recent investigations have indicated microRNA-26b (miR-26b) as a biomarker in the progression of SAH. Accordingly, the present study was designed to elucidate the role of miR-26b in influencing EBI following SAH and the downstream mechanisms. METHODS: Firstly, SAH rat models and neuron injury models were developed to assess the effect of miR-26b on EBI-like symptoms and subsequent inflammation. Dual-luciferase reporter gene assay was further implemented to evaluate the binding of miR-26b to its putative target gene STAT3. Loss-of-function and rescue experiments were performed to assess the functionality of miR-26b-mediated STAT3 in both models. RESULTS: miR-26b was found to target KLF4 and negative-modulate its expression, whereby aggravating EBI and inflammatory response in SAH rat models and stimulating hemoglobin-induced apoptosis in astrocytes. On the other hand, silencing of miR-26b reversed these changes in SAH rat models and hemoglobin (Hb)-induced astrocytes. miR-26b could further activate STAT3 via down-regulation of KLF4. Furthermore, KLF4 knockdown up-regulated HMGB1 to aggravate EBI following SAH. CONCLUSIONS: Collectively, our findings highlighted the ameliorative effect of miR-26b inhibition on EBI in SAH and the possible mechanism associated with the KLF4/STAT3/HMGB1 axis.

Down-regulated HDAC1 and up-regulated microRNA-124-5p recover myocardial damage of septic mice.

Studies have revealed the relationship between histone deacetylases (HDACs)/microRNAs (miRNAs) and sepsis, but little has ever investigated the mechanism of HDAC1/miR-124-5p in sepsis. Herein, we studied the impacts of HDAC1/miR-124-5p on myocardial damage of septic mice via regulating high-mobility group box chromosomal protein 1 (HMGB1). Septic mice were induced by cecal ligation and puncture. HDAC1, miR-124-5p and HMGB1 expression in myocardial tissues of septic mice were detected. Septic mice were injected with HDAC1 low expression-, miR-124-5p high expression- or HMGB1 low expression-related structures to observe cardiac function, inflammatory response, oxidative stress response, myocardial pathological changes and apoptosis in myocardial tissues of septic mice. The relationship of HDAC1/miR-124-5p/HMGB1 was verified. HDAC1 and HMGB1 expression were upregulated while miR-124-5p expression was decreased in myocardial tissues of septic mice. Restored miR-124-5p/depleted HDAC1 or HMGB1 recovered the cardiac function, improved cardiac function, inflammatory response, oxidative stress response, myocardial pathological changes and inhibit ed cardiomyocyte apoptosis in septic mice. HDAC1 bound to miR-124-5p which directly targeted HMGB1. This study suggests that down-regulated HDAC1 or up-regulated miR-124-5p recovers myocardial damage of septic mice via decreasing HMGB1.

Impact of perioperative high mobility group box chromosomal protein 1 expression on long-term outcomes in patients with esophageal squamous cell carcinoma.

BACKGROUND AND AIM: High mobility group box chromosomal protein-1 (HMGB-1) is a potential late mediator of sepsis and a possible risk factor for postoperative pulmonary complications after esophagectomy. This study aimed to determine the relationship between HMGB-1 and clinicopathological factors and long-term prognosis after esophagectomy for esophageal cancer. METHODS: We measured perioperative serum HMGB-1 levels using ELISA and HMGB-1 protein by immunohistochemistry expression in resected specimens. RESULTS: Postoperative serum HMGB-1 levels were significantly higher than preoperative levels. Preoperative serum HMGB-1 levels were significantly higher in patients with more intraoperative bleeding, longer intensive care unit stays, and postoperative pneumonia. Postoperative serum HMGB-1 levels were significantly higher in older patients and those with longer operation time and more intraoperative bleeding. There were significant differences in long-term outcomes according to postoperative but not preoperative serum HMGB-1 levels. Multivariate analysis demonstrated that advanced pathological stage, postoperative pulmonary complications, and higher postoperative serum HMGB-1 levels were independently associated with relapse-free survival and overall survival. Preoperative serum HMGB-1 levels were significantly higher in patients with high HMGB-1 expression than those with low HMGB-1 expression by immunohistochemistry, whereas such statistical differences were not observed in postoperative serum HMGB-1. There were no differences in relapse-free survival and overall survival according to HMGB-1 expression by immunohistochemistry. Serum HMGB-1 levels were significantly increased after esophagectomy for esophageal cancer. CONCLUSION: Elevated postoperative serum HMGB-1, which was associated not only with poor long-term but also short-term outcomes such as postoperative complications, might serve as a potential marker for prognosis in esophageal cancer.

Association of chemokine expression in anterior cruciate ligament deficient knee with patient characteristics: Implications for post-traumatic osteoarthritis.

BACKGROUND: Stromal cell-derived factor-1a (SDF-1α) and high mobility group box chromosomal protein 1 (HMGB1) are chemokines that can drive post-traumatic osteoarthritis (PTOA) induced by anterior cruciate ligament (ACL) injury. However, the influence of patient characteristics on expression of those chemokines remains unclear. Our aim was to determine the relationship between chemokine expression in synovial fluid (SF) of the ACL-deficient (ACL-D) knee and patient characteristics including time from injury, sex, and age. METHODS: SF samples were collected immediately prior to the first-time ACL reconstruction (ACLR) from 82 patients. Expression of SDF-1α and HMGB1 was measured with human-specific solid phase sandwich enzyme-linked immunosorbent assays. The expression levels between groups divided by time from injury, or age, or sex was compared using Student's t-test. The association of SDF-1α or HMGB1 levels with those variables was determined using regression analysis and Pearson product-moment correlation coefficient. RESULTS: Regression and correlation analysis indicated significant correlation between SDF-1α expression and time from injury in the cohort (r = -0.266, P = 0.016, n = 82) and in females (r = -0.386, P = 0.024, n = 34). Significant correlation was also observed between SDF-1α expression and age in the cohort (r = -0.224, P = 0.043, n = 82) and in males (r = -0.289, P = 0.046, n = 48). No significant correlation between HMGB1 expression and patient characteristics was detected. CONCLUSIONS: SDF-1α rather than HMGB1 might serve as a protein marker for monitoring the development of PTOA in the ACL-D knee, especially in female patients.

High Efficiency Removal of Cytokines and HMGB-1 by Continuous Hemofiltration With a Dual Layered Polyethersulfone Membrane: An Ex Vivo Study.

Cytokines and high mobility group box chromosomal protein-1 (HMGB-1) play key roles in inflammatory conditions. While hemofiltration has been shown to remove cytokines, removal of cytokines and HMGB-1 by hemofiltration using a polyethersulfone membrane has not been reported. This study aimed to test the hypothesis that the polyethersulfone membrane will achieve higher removal performance for substances including inflammatory cytokines compared to other hemofilters, while retaining low albumin removal capacity. Subjects were eight healthy volunteers. We collected 400 mL each of blood samples into containers with heparin and added 30 mg of lipopolysaccharide to spike cytokines and HMGB-1. After incubation at 39ºC for 12 h, each blood sample was circulated through a hemofiltration circuit with a polyethersulfone hemofilter (2.1 m2 or 1.1 m2 ) at a filtration flow rate of 2 L/h. Measurement samples were collected from arterial, venous, and ultrafiltrate sampling points. Concentrations of cytokines (IL-1ß, IL-4, IL-6, IL-8, IL- 10, and tumor necrosis factor [TNF-a]), HMGB-1, and albumin were determined at each time point (1, 4, 8, 12, and 24h). High sieving coefficients (SCs) above 0.8 were obtained for all cytokines except for TNF-a as well as HMGB-1, whereas the SC for albumin was less than 0.04 with both hemofilters. The hemofilter with a larger membrane area achieved significantly higher clearances for TNF-a and HMGB-1, and slower decreases in SCs over time for IL-1ß, IL-6, IL-8, TNF-a, and albumin. Continuous hemofiltration with a polyethersulfone membrane achieved high efficiency removal of cytokines and HMGB-1, without excessive removal of albumin.

Chrysin protects human osteoarthritis chondrocytes by inhibiting inflammatory mediator expression via HMGB1 suppression.

High­mobility group box chromosomal protein (HMGB­1) contributes to osteoarthritis (OA) by modulating various oxidative, inflammatory and apoptotic signaling pathways. The effect of chrysin (CH), a natural plant flavonoid, and its functional interaction with HMGB­1, was investigated in a chondrocyte model of OA. Human chondrocytes were pre­treated with CH, and then subsequently treated with IL­1ß to induce the formation of chondrocytes similar to those found in OA joints. Next, the expression level of HMGB­1 was determined by immunofluorescence and western blot analysis. Additionally, inflammatory factor expression was measured by ELISA, and cell apoptosis was analyzed with flow cytometry. To further explore the effects of CH, HMGB­1 expression was silenced following CH treatment with small interfering (si)RNA. The results demonstrated that CH inhibited cell apoptosis, dose­dependently reduced matrix metalloproteinase (MMP) 13, collagenase and IL­6 expression, and increased collagen α­1 (II) chain (COL2A1) expression in human osteoarthritis chondrocytes. These effects of CH were accompanied by decreased HMGB­1 expression. Additionally, the expression of MMP13, collagenase, IL­6 and COL2A1, as well as apoptosis, was significantly reduced by HMGB­1 siRNA. These results demonstrated that HMGB­1 is critical for the protective effect of CH on human osteoarthritis chondrocytes, including cell apoptosis and inflammatory factor inhibition, which suggests that CH may have potential therapeutic effect in treating OA by protecting human osteoarthritis chondrocytes via HMGB1 suppression.

Glycyrrhizin Treatment Facilitates Extinction of Conditioned Fear Responses After a Single Prolonged Stress Exposure in Rats.

BACKGROUND/AIMS: Impaired fear memory extinction is widely considered a key mechanism of post-traumatic stress disorder (PTSD). Recent studies have suggested that neuroinflammation after a single prolonged stress (SPS) exposure may play a critical role in the impaired fear memory extinction. Studies have shown that high mobility group box chromosomal protein 1 (HMGB-1) is critically involved in neuroinflammation. However, the role of HMGB-1 underlying the development of impairment of fear memory extinction is still not known. METHODS: Thus, we examined the levels of HMGB-1 in the basolateral amygdala (BLA) following SPS using Western blot and evaluated the levels of microglia and astrocytes activation in the BLA after SPS using immunohistochemical staining. We then examined the effects of pre-SPS intra-BLA administration of glycyrrhizin, an HMGB1 inhibitor, or LPS-RS, a competitive TLR4 antagonist, on subsequent post-SPS fear extinction. RESULTS: We found that SPS treatment prolonged the extinction of contextual fear memory after the SPS. The impairment of SPS-induced extinction of contextual fear memory was associated with increased HMGB1 and Toll-like receptor 4 (TLR4) levels in the BLA. Additionally, the impairment of SPS-induced extinction of contextual fear memory was associated with increased activation of microglia and astrocyte in the BLA. Intra-BLA administrations of glycyrrhizin (HMGB-1 inhibitor) or LPS-RS (TLR4 antagonist) can prevent the development of SPS-induced fear extinction impairment. CONCLUSION: Taken together, these results suggested that SPS treatment may not only produce short term effects on the HMGB1/TLR4-mediated pro-inflammation, but alter the response of microglia and astrocytes to the exposure to fear associated contextual stimuli.

Effects of bone marrow MSCs transfected with sRAGE on the intervention of HMGB1 induced immuno-inflammatory reaction.

BACKGROUND: High mobility group box chromosomal protein 1 (HMGB1) is an important proinflammatory molecule in many inflammatory disorders, but little is known about its role in acute liver failure (ALF). In this study, we determined the plasma and hepatic tissue levels of HMGB1 in a d-galactosamine-induced rat ALF model and investigated the effect of soluble receptor for advanced glycation end products (sRAGE) on ALF successfully. METHODS: Male Sprague-Dawley rats were divided into five groups randomly. Group A (Control group, n=20) received administrated saline via peritoneal cavity. Group B (ALF group, n=20) induced by d-galactosamine (0.6 g/kg) via peritoneal cavity. Group C (HMGB1 group, n=20) were treated with HMGB1 recombination protein (200 µg/kg) via penile vein after ALF model induced. Group D (sRAGE group, n=20) received administrated sRAGE recombination protein (400 µg/kg) via penile vein after ALF model induced. Group E (sRAGE-MSC group, n=20) received 3 × 10(6) MSC transplantation which could maintain a stable expression of sRAGE via penile vein after ALF model induced. Liver function, level of cytokines and liver pathological changes were measured. RESULTS: We determined that the plasma levels and hepatic tissue levels of HMGB1 were significant increased in ALF model (P<0.05). SRAGE group and sRAGE-MSC group could significantly prolong ALF rat survival time, as well as improve its liver functions, inflammatory cytokines level and hepatocytes necrosis. CONCLUSION: SRAGE as a ligand decoy has illustrated largely beneficial effects on reducing immuno-inflammatory response, which holds promise for the identification of potential therapeutic targets and/or biomarkers of RAGE activity in ALF.

Effect of shHMGB1 knockdown on renal function improvement and cell proliferation of glomeruli in lupus nephritis mice / 中华肾脏病杂志

Objective To investigate the effect of high mobility group box chromosomal protein 1 (HMGB1) knockdown on improving renal function and decreasing cell proliferation of glomeruli in lupus nephritis (LN) MRL/Faslpr mice.Methods Twenty-four MRL/Faslpr mice were randomly divided into 3 groups:LN model group,shHMGB1 group and empty plasmid group.Besides,eight MRL/MpJ mice,age and mass matched to the MRL/Faslpr mice,were chosen as normal control group (shNC group).Electroporation technology was used for in vivo transfection in treatment group.shHMGB1 group and empty plasmid group were transfected by electroporation technology for shHMGB1 plasmids and empty plasmid,LN model group and normal control group were transfected only with saline.Automatic biochemical analyzer was used to detect serum urea nitrogen (BUN) and creatinine (Scr) levels and 24 h urinary protein (UP) was tested.HE staining was used to detect the pathological change of renal tissues; real-time PCR,immunofluorence staining and Western blotting were used to detect the mRNA and protein expression of HMGB1 and PCNA.Results (1) The HMGB1 mRNA and protein expression in LN group increased compared with those in control group,HMGB1 mRNA and protein expression in shHMGB1 group reduced compared with those in LN model group (all P ＜ 0.05).(2) 24 h UP of MRL/Faslpr mice in shHMGB1 group significantly reduced compared with those in LN group (P ＜ 0.05).(3) Immunofluorence and Western blotting showed that positive signal of proliferating cell nuclear antigen (PCNA) was mainly located in nuclei,PCNA mRNA and protein in glomeruli of LN model group increased compared with those of control mice (P ＜ 0.05).Interestingly,PCNA expression in glomeruli of shHMGB1 group remarkably reduced (P ＜ 0.05).Conclusions shHMGB1 significantly improves renal function and decreases cell proliferation of glomeruli in LN MRL/Faslpr mice.

Decreased serum platelet derived growth factor BB levels in acute and increased in chronic pancreatitis.

AIM: To examine circulating growth factor concentrations in patients with acute pancreatitis (AP) and chronic pancreatitis (CP), and walled-off pancreatic necrosis (WOPN). METHODS: Forty patients with mild AP, 40 patients with alcoholic CP, 33 patients with WOPN and 40 healthy subjects were examined. Serum concentrations of platelet derived growth factor BB (PDGF-BB), transforming growth factor ß-1 (TGFß-1), chemerin and high-mobility group box chromosomal protein 1 (HMBG1) were assayed by enzyme linked immunosorbent assay. RESULTS: Patients with mild AP and those with WOPN had significantly lower serum levels of PDGF-BB compared to healthy subjects (4.0 ± 0.61 ng/mL vs 6.2 ± 0.76 ng/mL, P = 0.027, and 1.60 ± 0.31 ng/mL vs 6.2 ± 0.76 ng/mL, P < 0.001, respectively), while CP was associated with higher serum levels of PDGF-BB (12 ± 1.3 ng/mL vs 6.2 ± 0.76 ng/mL, P < 0.001). Circulating TGFß-1 and chemerin levels were elevated in CP patients (57 ± 3.6 ng/mL vs 39 ± 3.6 ng/mL, P < 0.001 and 73 ± 7.2 ng/mL vs 48 ± 2.3 ng/mL, P < 0.001, respectively), but not in patients with AP and WOPN. No significant changes in serum HMBG1 levels were found either in patients with AP, WOPN or CP. CONCLUSION: The serum levels of some growth factors and cytokines differ significantly in AP, WOPN and CP. These data suggest that selected growth factors and cytokines may be considered as potential diagnostic biomarkers in patients with pancreatic diseases.

(Pro)renin receptor blocker improves survival of rats with sepsis.

BACKGROUND: The renin-angiotensin system (RAS) affects inflammatory responses during sepsis. Nonproteolytic activation of prorenin by the (pro)renin receptor has recently been shown to stimulate the tissue RAS. In the present study, the effect of (pro)renin receptor blocker (PRRB) pretreatment on sepsis in a rat cecal ligation and puncture (CLP) model was investigated. MATERIALS AND METHODS: Male Sprague-Dawley rats underwent CLP and were randomly divided into two groups: PRRB-treated group and control peptide-treated group. Survival was analyzed for 7 d after CLP. The serum concentrations of cytokines and high-mobility group box chromosomal protein 1 (HMGB1) were measured at three time points (0, 3, and 6 h after CLP). Hematoxylin-eosin staining and immunohistochemical staining for nonproteolytically activated prorenin and HMGB1 were performed on the cecum to assess pathologic changes found 6 h after CLP. RESULTS: Treatment with PRRB improved the survival rate of the post-CLP septic rats (P = 0.023). PRRB also significantly reduced serum tumor necrosis factor-α, interleukin-1ß, and HMGB1 levels 6 h after CLP. In CLP rats that were treated with control peptide, the expression of activated prorenin was elevated in peritoneal foam cells. Moreover, expression of HMGB1 was increased in peritoneal inflammatory cells. In contrast, both were markedly suppressed in CLP rats that were treated with PRRB. CONCLUSIONS: PRRB significantly improved the survival rate of rats with clinically relevant sepsis, possibly by attenuating a sepsis-induced systemic inflammatory response. We propose that overactivation of the RAS by activation of prorenin in foam cells may be a significant contributor to sepsis.

Increased of serum high-mobility group box chromosomal protein 1 correlated with intestinal mucosal barrier injury in patients with severe acute pancreatitis.

BACKGROUND: Secondary infections are the leading cause of death in patients with severe acute pancreatitis (SAP). The gut represents the main source of pancreatic contamination and related septic complications. High-mobility group box chromosomal protein 1 (HMGB1) was recently identified to play an important role in the SAP intestinal mucosal barrier dysfunction. OBJECTIVE: To investigate the correlation of high-mobility group box 1 (HMGB1) with intestinal barrier injury and infections in patients with severe acute pancreatitis (SAP). METHODS: The serum levels of HMGB1, amylase, lipase, and biochemical indicators were measured in 80 patients with SAP at the time of admission. Furthermore, relationship between their serum HMGB1 levels and intestinal barrier injury, infection and other clinical factors were analyzed. RESULTS: The mean value of serum HMGB1 levels was significantly higher in patients with SAP (6.02 ± 2.42 ng/mL) than that in healthy volunteers (1.87 ± 0.63 ng/mL). Serum HMGB1 levels were significantly positively correlated with the Ranson score. The HMGB1 levels were higher in patients with infection during the clinical course, the HMGB1 levels in non-survivors were higher than those in survivors, and positively correlated with DAO activity, L/M ratio, the concentration of endotoxin (R = 0.484, P <0.01). CONCLUSIONS: HMGBl level of patients with severe acute pancreatitis was significantly increased, and can be used as an important indicator to determine the intestinal barrier dysfunction and infection.

HMGB1 gene polymorphisms in patients with chronic hepatitis B virus infection.

AIM: To characterize high mobility group box chromosomal protein 1 (HMGB1) polymorphisms in patients infected with hepatitis B virus (HBV) and determine the different patterns in patient subgroups. METHODS: A total of 1495 unrelated Han Chinese HBV carriers were recruited in this hospital-based case-control study. The HMGB1 1176 G/C polymorphism was genotyped by polymerase chain reaction-restriction fragment length polymorphism assay. RESULTS: A significant association was observed between HMGB1 1176 G/C polymorphism and outcome of HBV infection. The subjects bearing 1176G/G genotype had an increased risk of susceptibility to chronic hepatitis B, liver cirrhosis and severe hepatitis B when compared with those bearing at least one 1176C allele. CONCLUSION: Patients with 1176G/G genotype of HMGB1 gene are more likely to have a progressive status in HBV infection.

High mobility group box chromosomal protein 1 promotes IL-18 production and IL-18 receptor expression in macrophages / 第二军医大学学报

Objective: To investigate whether high mobility group box chromosomal protein 1 (HMGB1) can activate macrophages to secrete IL-18. Methods: Mouse peritoneal macrophages were cultured with HMGB1 for indicated period, then the mRNA and protein expression of IL-18 and IL-18 receptors were examined by real-time PCR, ELISA, and flow cytometric analysis. Toll-like receptor (TLR) 2 and 4 agonists (1 μg/ml Pam3Cys or 100 ng/ml LPS) were used as parallel controls. Results: Two hours after culture with HMGB1(100 ng/ml), IL-18 mRNA expression was greatly increased. The expression of IL-18 protein was also greatly increased 24 h after culture with HMGB1, and the expression of IL-18R was slightly up-regulated. Pam3Cys (1 μg/ml) and LPS(100 ng/ml) could promote the expression of IL-18 at both mRNA and protein levels in the macrophages, and could up-regulate IL-18 receptors. Conclusion: HMGB1 can directly activate macrophages to secrete IL-18 and to express IL-18 receptor, suggesting that IL-18 may mediate the proinflammatory activity of HMGB1.

Role of high mobility group box chromosomal protein 1 in pathogenesis of ulcerative colitis in mice / 中华消化内镜杂志

Objective To establish ulcerative colitis(UC)model in BALB/c mice and to investigate the role of high mobility group box chromosomal protein 1(HMGBI)in pathogenesis of UC.Methods Thirty-two BALB/c mice were randomly divided into UC group(n=24,which were fed with 3%dextran sulfate 80dium solution)and control group(n=8,which were fed with water).The animals were sacrificed at 24.96 and 1 68 hours,respectively,to collect samples of colon and blood.The sernm level of HMGB1 was measured with ELISA and the expression of HMGB1 in colon was determined by Western blotting analysis.Results Histological scoring increased with the induction of the model,and manifestation of colon mucosa at 168h was similar with that of UC in human.The serum level of HMGB1 was slightly higer at 24 h than that of control(5.09±0.61 μg/L vs 4.49±0.53μg/L,P＞0.05),and reached a peak at 96 h (14.74±0.60 μg/L,P＜0.01),decreased at 168 h(9.03±0.78μg/L,P＜0.01).The expression 0.05).significandy increased at 96h(0.76±0.03,P＜0.05)and at 168 h(0.77±0.04,P＜0.05).Conclusion HMGB1 might be involved in pathologic changes of UC at a later stage.

Arsenic trioxide inhibits proliferation of rat synoviocyte line stimulated with TNF-? and its mechanism / 基础医学与临床

Objective To investigate the effect and possible mechanism of arsenic trioxid(As2O3)on proliferation of RSC-364 synoviocyte lines stimulated with TNF-?.Methods RSC-364 synoviocytes were cultured with standard medium as control group or medium supplemented with 10 ?g/LTNF-? and different concentrations of As2O3 respectively. MTT assay were carried out to study cell proliferation. Proliferation index (PI) and cell cycle were detected by flow cytometry (FCM). RT-PCR was used to detect the mRNA expression of High mobility group box chromosomal protein (HMGB)1. HMGB-1 and proliferation cell nuclear antigen (PCNA) proteins were detected by immunocytochemistry and FCM. Results (1)As2O3 inhibited proliferation of cell lines stimulated by TNF-? time-dependently and dose-dependently. (2)Compared with normal group, TNF-? up-regulated HMGB-1 protein and mRNA as well as PCNA protein. HMGB-1 protein was not only in nuclear but also in cytoplasm by immunocy-tochemistry. As2O3 down-regulated mRNA and protein of HMGB-1 in a dose-dependent manner; so did PCNA proteins (P

Role of HMGB 1 in the pathogenesis of adjuvant-induced arthritis in rats / 中华风湿病学杂志

Objective To demonstrate high mobility group box chromosomal protein 1(HMGBI) expression in synovium and joint,and to identify the role of HMGB1 in the pathogenesis of synovitis and joint destruction in adjuvant-induced arthritis(AA).Methods AA of 15 male rats were induced in SD rats by intradermal injection of 100?l Freud's complete adjuvant in the foot pad of the left hind paw.All rats were killed at the 18th day.Synovium and joints were collected for histopathology studies and determining the expression of HMGB1 by immunohistochemistry,and serum was collected for determining the expression of HMGB1 by western blotting analysis.Results Immunostaining of specimens from normal rats showed that HMGB1 was primarily confined to the nucleus of synoviocytes with occasional cytoplasmic staining.In contrast, inflammatory synovial tissues from AA rats showed a distinctly different HMGB1 staining pattern.Nuclear HMGBI expression was accompanied by a cytoplasmic staining in many mononuclear cells.The cytoplasmic HMGB1 expression in synovium of AA rats is significantly higher than that of normal rats.Additionally,HMGBI was highly expressed in the nuclei and cytoplasm of the subchondral chondrocytes and inflammatory cells in bone erosion in AA rats(P＜0.01),while fewer positive cytoplasmic staining of HMGB1 was found in chondrocytes and fewer positive nuclear staining was found in bone cells in normal rats.HMGB1 concentration was significantly higher in serum of AA rats than that in normal rats(P＜0.001).Conclusion The cytoplasmic HMGBI expression in synovium and joints is greatly upregulated;the level of HMGB1 in serum is increased in AA rats which suggests a patbogenetic role of HMGB1 in synovitis and bone destruction of adjuvant-induced arthritis.

Structure and function of extracellular HMGB-1 / 医学研究生学报

HMGB-1, an ubiquitously expressed 25-KD nucleoprotein among mammals, belongs to the HMG family. Recent studies have identified that HMGB-1 is secreted by activated monocytes/macrophages via a non-classical ,vesicle-mediated secretory pathway. Extracellular HMGB-1 is an important proinflammatory cytokine. It participates in the pathogenesis of many diseases such as rheumatoid arthritis, sepsis , acute lung injury, and even leads animals death. Further studies of the mechanism and function of extracellular HMGB-1 may provide a novel strategy for the diagnosis and treatment of these diseases.