Concentration Of HMGB1 Research Articles

Changes in pro-inflammatory markers and leucine concentrations in response to Nordic Walking training combined with vitamin D supplementation in elderly women

Mechanisms underpinning age-related decreases in muscle strength and muscle mass relate to chronic inflammation. Physical activity induces an anti-inflammatory effect, but it is modulated by additional factors. We hypothesized that vitamin D, which has also anti-inflammatory activity will modify adaptation to exercise and reduce inflammation in elderly women. Twenty-seven women aged 67 ± 8 years were included and divided into groups with baseline vitamin D concentration more than 20 ng mL−1 (MVD) and less than 20 ng mL−1 (LVD). Both groups performed 1 h Nordic Walking (NW) training combined with vitamin D supplementation for 12 weeks. Serum concentrations of inflammation markers, branched amino acids, vitamin D, muscle strength and balance were assessed at the baseline and three days after intervention. The training caused the significant decrease in concentration of pro-inflammatory proteins HMGB1 (30 ± 156%; 90% CI) and IL-6 (−10 ± 66%; 90% CI) in MVD group. This effects in group MVD were moderate, indicating vitamin D as one of the modifiers of these exercise-induced changes. Rise of myokine irisin induced by exercise correlated inversely with HMGB1 and the correlation was more pronounced at the baseline as well as after training among MVD participants. Although the intervention caused the leucine level to rise, a comparison of the recorded response between groups and the adjusted effect indicated that the effect was 20% lower in the LVD group. Overall the applied training program was effective in reducing HMGB1 concentration. This drop was accompanied by the rise of myokine irisin and better uptake of leucine among women with higher baseline vitamin D.

HMGB1: a novel protein that induced platelets active and aggregation via Toll-like receptor-4, NF-κB and cGMP dependent mechanisms.

BackgroundThrombotic diseases are a group of prevalent and life-threatening diseases. Selective inhibition of pathological thrombosis holds the key to treat variety of thrombotic diseases. The pathological thrombosis can be induced by either tissue necrosis and deregulated inflammation. HMGB1, as an important proinflammatory cytokine and a late mediator, also involves on thrombosis disease. However, the underlying mechanisms are not fully understood.MethodsImmunofluorescence, ELISA assay, Platelet Aggregation, Thromboelastogram (TEG) analyzes. Flow cytometric analysis and Western blot analysis were used to investigated the role of HMGB1 in platelet aggregation and obtained following observations.ResultsBy doing so, we obtained the following observations: i) Highly purified HMGB1 recombinant protein induces platelet aggregation and secretion in a dose-dependent manner in the presence of serum. ii) Low concentration of extracellular HMGB1 could synergistically promote subthreshold concentration of collagen or thrombin induced platelet aggregation. iii) Extracellular HMGB1 promoted platelet aggregation in a platelet-expressed GPIIb/IIIa-dependent manner. iv) We proposed that extracellular HMGB1 seems to promote the phosphorylation of GPIIb/IIIa and subsequent platelet aggregation via TLR4/NF-κB and cGMP pathway.ConclusionsIn this study, we provide evidence for the hypothesis that HMGB1 interact with platelet might play an important role in the haemostasis and thrombotic diseases. Our research might be provide an interesting avenue for the treatment of thrombotic diseases in the future.

High-mobility group box-1 protein in adenine-induced chronic renal failure and the influence of gum arabic thereon.

Pathogenesis of adenine-induced chronic renal failure may involve inflammatory, immunological and/or oxidant mechanisms. Gum arabic (GA) is a complex polysaccharide that acts as an anti-oxidant which can modulate inflammatory and/or immunological processes. Therefore, we tested here the effect of GA treatment (15 % in the drinking water for 4 weeks) in plasma and urine of rats, on a novel cytokine that has been shown to be pro-inflammatory, viz, DNA-binding high-mobility group box-1 protein (HMGB1). Adenine (0.75 % in the feed, 4 weeks) significantly increased indoxyl sulphate, urea and creatinine concentrations in plasma, and significantly decreased the creatinine clearance. GA significantly abated these effects. The concentrations of HMGB1 in urine before the start of the experiment were similar in all four groups. However, 24 h after the last treatment, adenine treatment increased significantly the concentration of HMGB1 when compared with the control. GA treatment did not affect the HMGB1 concentration in urine. Moreover, the concentration of HMGB1 in plasma obtained 24 h after the last treatment in rats treated with adenine was drastically reduced compared with the control group. This may explain its significant rise in urine. In conclusion, HMGB1 can be considered a potentially useful biomarker in adenine induced CRF and its treatment.

Targeting HMGB1 Increased the Sensitivity of MM Cells to Chemotherapy

Background ：Multiple myeloma (MM) is an malignant disease of clonal plasma cell hyperplasia, which incidence is increasing in recent years. Chemotherapy is the main method to treat MM, but because of drug resistance, MM is still an incrurable disease. High-mobility group box 1 protein (HMGB1) is a chromatin associated nuclear protein, which participated in DNA damage repair , rearrangement, and it also as an extracellular damage associated molecular pattern molecule(DAMP) involved in inflammation, neoplastic progression, angiogenesis, invasion and metastasiss and drug resistance of kinds of tumor cells. There’s no research about the role of HMGB1 in multiple myeloma before.Methods: First, We detected HMGB1 mRNA and protein expression level in MM cell lines and primary MM cells by semiquantitative real time-polymerase chain (qRT-PCR)and western blot respectively. The concentration of HMGB1 in the culture supernatants of MM cell lines and primary MM cells was detected by ELISA. Second, we constructed Lentivirus vector with HMGB1 shRNA, infected the lentivirus to MM cells to knockdown HMGB1 expression. Then Chemo-drugs (ADM, quercetin and bortezomib) were added to MM cells, flow cytometry was used for the detection of cell apoptosis.Results:MM cell line and primary MM cell all express HMGB1 with high level. The concentration of HMGB1 in the MM cell supernatants was significantly elevated after chemotherapy treatment compared with untreated cells(p<0.05), and HMGB1 in MM patients’ bone marrow supernatants was very high. Knockdown of HMGB1 increased 8226 and ARP-1 cell apoptosis induced by ADM and quercetin (NC shRNA VS HMGB1 shRNA, p<0.05), but there’s no significant difference induced by bortezomib.Conclusions: Our study showed that the concentration of HMGB1 in the MM cell supernatants was significantly elevated after chemotherapy treatment. Further more, knockdown of HMGB1 by shRNA increased the sensitivity of MM cells to chemotherapy. DisclosuresNo relevant conflicts of interest to declare.

The protective effect of interleukin-10 on lipopolysaccharide-induced acute lung injury in rats by attenuating the release of extracellular high mobility group protein 1

Objective This study aimed to investigate the effect of interleukin (IL)-10 on extracellular release of high mobility group protein 1 (HMGB1) in lipopolysaccharide (LPS)-induced acute lung injury in rats and its possible mechanism.Methods LPS (5 mg/kg,ip) induced acute lung injury model was used in our experiment,the healthy male Sprague-Dawley rats,weighed 180 g-220 g,were randomly divided into four groups:control group only used phosphate buffered solution (PBS) (group P,n=6),PBS+IL-10 group (group PI,n=6),acute lung injury group also LPS group (group L,n=30),LPS+interleukin-10 group(group LI,n=30).In the group L and LI,4,8,16,24 h and 48 h after the injection of LPS,the lung wet/dry weight ratio(W/D) and the concentration of the total protein in bronchoalveolar lavage fluid (BALF) were analyzed.The cytokines [tumor necrosis factor-α(TNF-α) and IL-6] in bronchoalveolar lavage fluid were detected by enzyme-linked immunosorbent assay.Hitophathological changes in lung tissue were observed by hematoxylin-eosin staining,and the expression of HMGB1 was analyzed by Western Blot.Results After using of LPS,the W/D and the concentration of the total protein in BALF in group L were (5.68±0.12) mg/L and (254± 105)mg/L,which were increased by 12％ and 297％(P＜0.05),compared with the group P,the concentration of TNF-α and IL-6 in BALF,HE staining of the lung tissue infiltration and the expression of HMGB1 in the lung tissue were all increased (P＜0.05).However after the intratracheal spray of IL-10,the W/D and the concentration of the total protein in BALF in group LI were (5.28±0.14) mg/L and (109±48) mg/L,which were decreased by 7％ and 57％(P＜0.05),compared with the group L,the level of inflammatory factors,lung tissue infiltration and the concentration of HMGB1 were all decreased (P<0.05).Conclusions IL-10 can attenuate the injury induced by LPS in acute lung injury.The mechanism may be due to the effect of decreasing the proinflammatory cytokines and down-regulating the expression of HMGB1. Key words: Interleukin-10; Lipopolysaccharide; Acute lung injury; High mobility group protein 1

Human Resistin Promotes Neutrophil Proinflammatory Activation and Neutrophil Extracellular Trap Formation and Increases Severity of Acute Lung Injury

Although resistin was recently found to modulate insulin resistance in preclinical models of type II diabetes and obesity, recent studies also suggested that resistin has proinflammatory properties. We examined whether the human-specific variant of resistin affects neutrophil activation and the severity of LPS-induced acute lung injury. Because human and mouse resistin have distinct patterns of tissue distribution, experiments were performed using humanized resistin mice that exclusively express human resistin (hRTN(+/-)(/-)) but are deficient in mouse resistin. Enhanced production of TNF-α or MIP-2 was found in LPS-treated hRtn(+/-/-) neutrophils compared with control Rtn(-/-/-) neutrophils. Expression of human resistin inhibited the activation of AMP-activated protein kinase, a major sensor and regulator of cellular bioenergetics that also is implicated in inhibiting inflammatory activity of neutrophils and macrophages. In addition to the ability of resistin to sensitize neutrophils to LPS stimulation, human resistin enhanced neutrophil extracellular trap formation. In LPS-induced acute lung injury, humanized resistin mice demonstrated enhanced production of proinflammatory cytokines, more severe pulmonary edema, increased neutrophil extracellular trap formation, and elevated concentration of the alarmins HMGB1 and histone 3 in the lungs. Our results suggest that human resistin may play an important contributory role in enhancing TLR4-induced inflammatory responses, and it may be a target for future therapies aimed at reducing the severity of acute lung injury and other inflammatory situations in which neutrophils play a major role.

Evaluation of High-Mobility Group Box 1 Protein Concentration in Serum of Patients with M. tuberculosis Infection

Infection with Mycobacterium tuberculosis is accompanied by an intense inflammatory response. Recently, a new mediator of inflammation, HMGB1 protein has been identified that contributes to acute lung injury. However, its role in the systemic inflammatory response in tuberculosis has not been thoroughly investigated. We investigated the systemic levels of HMGB1 and TNF-α in patients with active and latent lung tuberculosis as a prognostic marker of disease activity. The study was performed to 70 patients with confirmed Mycobacterium tuberculosis infection and other than tuberculosis lung diseases and in 20 healthy persons. Serum HMGB1 and TNF-α concentrations were measured by ELISA. The highest concentration of HMGB1 was detected in the bloodstream of people with Mtb infection (latent and active). Its concentration increased significantly in sera of patients with active tuberculosis (47.5 ng/ml), compared to patients with other lung diseases (36.87 ng/ml). TNF-α had significantly higher concentration in a patients group compared to healthy controls, with the highest concentration in the LTBI group of patients (0.136 ng/ml). We observed a strong positive correlation between TNF-α and HMGB1 concentrations in patients with tuberculosis infections. We conclude that HMGB1 is secreted during active and latent tuberculosis in the highest amounts compared to other lung diseases.

PP125. High mobility group box 1 protein (HMGB1): A pathogenic role in preeclampsia?

A central pathogenic mechanism of preeclampsia is believed to be the production by the hypoxic placenta of various mediators which promote inflammation and oxidative stress when released into the maternal circulation. The high mobility group box 1 protein (HMGB1) is a ubiquitous nuclear protein. In conditions of hypoxic cellular stress or necrosis, HMGB1 is released into the extracellular milieu. Extracellular HMGB1 has proinflammatory effects, due to the engagement of various cell membrane receptors, notably the receptor for advanced glycation products (RAGE). In preeclampsia, there is evidence for activation of RAGE, and enhanced amounts of HMGB1 have also been demonstrated in the placenta and amniotic fluid, but not, so far, in maternal blood. We hypothesize therefore that, in preeclampsia, the concentration of HMGB1 is abnormally high in maternal blood. We enrolled 16 women in third trimester pregnancy and suffering from preeclampsia (blood pressure > 140/90mmHg with significant proteinuria), 16 women with normal pregnancies who were matched pairwise with the former for BMI and gestation week, and 16 non pregnant healthy women, matched for age with the other two groups. HMGB1 was assessed in peripheral blood with a commercial ELISA kit. The variance between the three groups was appreciated using an ANOVA analysis. Significance was considered for a probability value of < 0.5. The median [interquartile range] HMGB1 concentrations (in ng/mL) were 2.1 [1.1-3.2] in preeclamptic pregnancies, 1.1 [1.0-1.2] in normal pregnancies (p<0.05 vs preeclamptic group), and 0.6 [0.5-0.8] in non pregnant women (p<0.01 vs both other groups). In third trimester pregnancy, the presence of preeclampsia is associated with an approximately two-fold increase of HMGB1 concentration in maternal peripheral blood. Considering its known proinflammatory effects, HMGB1 could be one mediator responsible for the maternal manifestations of preeclampsia.

Circulating high-mobility group box 1 and cardiovascular mortality in unstable angina and non-ST-segment elevation myocardial infarction

ObjectiveHigh-mobility group box 1 (HMGB1) is a damage-associated molecular pattern molecule, which suggests a potential role of this protein in the pathophysiology of acute coronary syndrome (ACS). Circulating HMGB1 has been shown to be independently associated with cardiac mortality in ST-segment elevation myocardial infarction. However, its prognostic value remains unclear in unstable angina and non-ST-segment elevation myocardial infarction (UA/NSTEMI). MethodsHMGB1, high-sensitivity C-reactive protein (hsCRP), cardiac troponin I and B-type natriuretic peptide concentrations were measured on admission in 258 consecutive patients (mean age of 67 years) hospitalized for UA/NSTEMI within 24h (mean, 7.4h) of the onset of chest symptoms. ResultsA total of 38 (14.7%) cardiovascular deaths, including 10 in-hospital deaths, occurred during a median follow-up period of 49 months after admission. In a stepwise Cox regression analysis including 19 well-known clinical predictors of ACS, HMGB1 [relative risk (RR) 3.24 per 10-fold increment; P=0.0003], cardiac troponin I (RR 1.83 per 10-fold increment, P=0.0007), Killip class>1 (RR 4.67, P=0.0001) and age (RR 1.05 per 1-year increment, P=0.03), but not hsCRP, were independently associated with cardiovascular mortality. In-hospital and cardiovascular mortality rates were higher in patients with increased HMGB1 (≥2.4ng/mL of median value) than those without increased HMGB1 (6.3% vs. 1.5%, P=0.04; and 23% vs. 6.9%, P=0.0003). ConclusionCirculating concentration of HMGB1 on admission may be a potential and independent predictor of cardiovascular mortality in patients hospitalized for UA/NSTEMI within 24h of onset.

C-terminal domain of nonhistone protein HMGB1 as a modulator of HMGB1–DNA structural interactions

The HMGB1 protein (High Mobility Group protein 1) participates in the formation of functionally significant DNA-protein complexes. HMGB1 protein contains two DNA-binding domains and negatively charged C-terminal region. The latter consists of continuous sequence of dicarboxylic amino acids residues. Structural changes in DNA-protein complexes were studied by circular dichroism spectroscopy (CD) and atomic force microscopy (AFM). Natural HMGB1 and recombinant protein HMGB1(A + B) lacked negatively charged C-terminal region were used. The DNA–HMGB1(A + B) complexes demonstrate an unusually high optical activity in 150 mM NaCl solutions. AFM of the latter complexes shows, that at the low concentration of HMGB1 in the complex the protein is distributed along DNA in a random way. Increase of HMGB1 content leads to cooperative interaction and a redistribution of the bound protein molecules on DNA is observed. Based on the data obtained we conclude that protein–protein interactions play a key role in the formation of highly ordered DNA–HMGB1 complexes. It was shown that C-terminal domain modulate the interactions of DNA with HMGB1 protein. We suggest that the C-terminal domain of HMGB1 also modulates the “packing” of HMGB1 molecules on the DNA.

Combined effect of high mobile group box-1 protein and lipopolysaccharide on release of cytokines from human HepG2 cells

To study the effects of high mobile group box-1 protein (HMGB1) and lipopolysaccharide (LPS) singly or in combination on release of cytokines from human liver carcinoma cell line (HepG2). HepG2 cells were cultured, and purified HMGB1 protein was prepared by chromatography on Ni(2+)-NTA Sepharose column under natural conditions with recombinant expression plasmid pET14b-HMGB1. Different concentrations of HMGB1 (0, 0.01, 0.1, 1, 10 mg/L) and LPS (0, 0.1, 1, 10, 100 mg/L) were added into the cultured cells for 24 hours, respectively. Then the supernatant were collected to detect the levels of granulocyte/macrophage colony stimulating factor (GM-CSF), interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1 beta (IL-1 beta), IL-2, IL-4, IL-6, IL-8, IL-10, and IL-12 by using LiquiChip system. Lastly, HepG2 cells were co-stimulated with 10 mg/L LPS and 1 mg/L HMGB1 for 24 hours. The supernatant were collected to determine the levels of above ten of cytokines . The expression and release of IL-6 and IL-8 increased from HepG2 cells after being stimulated by LPS in a dose-dependent manner, but there were no changes in other eight kinds of cytokines (P<0.05 or P<0.01). Low concentration of HMGB1 could up-regulate the expression of IL-6 and IL-8 in HepG2 cells (both P<0.01). But the extent of induction decreased with higher concentration of HMGB1. Similar to LPS, there was no effect of HMGB1 on the expression of other eight kinds of cytokines from cultured HepG2 cells. Furthermore, high concentration of HMGB1 could obviously inhibit the upregulation of IL-6 and IL-8 by high concentration of LPS when the HepG2 cells were co-stimulated with LPS and HMGB1 (both P<0.01). HepG2 cells could only express and release a few kinds of cytokines when the cells were stimulated with pro-inflammatory agents, such as LPS or HMGB1. Two kinds of cytokines, IL-6 and IL-8 could be up-regulated by LPS and low concentration of HMGB1, and HMGB1 acted as an inhibitor of LPS to down-regulate the expression and release of IL-6 and IL-8 from HepG2 cells.

Influence of high mobility group box-1 protein on the correlation between regulatory T cells and CD4+ CD25- T cells of spleen in mice

To investigate the influence of high mobility group box-1 protein (HMGB1) on the immunosuppression function of splenic regulatory T cells (Tregs) and its potential regulatory mechanism underlying the effect on CD4+ CD25- T cells in mice. CD4+ CD25+ Tregs isolated from the spleens of male BALB/c mice by magnetic beads were seeded on 96-well (1 x 10(5) cells/well) cell culture plates coated with 1 microg/ml anti-CD3 and soluble CD28. After being stimulated with HMGB1 for different time and concentrations, the secretions of IL-2 and IL-10 were analyzed by ELISA. Tregs stimulated for 72 hours were cultured with CD4+ CD25- T cells together. The suppressive activity of CD4+ CD25+ Treg to CD4+ CD25- T cells was analyzed by MTT test. IL-2, IL-10, IL-4, and interferon (IFN)-gamma in the cell suspensions were determined by ELISA. After stimulation with HMGB1, the suppressive activity of splenic Tregs in mice were significantly down-regulated at 72 hours, when the proportion of Tregs to CD4+ CD25- T cells was 1 : 1. The secretion of IL-2 of Tregs stimulated by HMGB1 was not markedly changed (P > 0.05), while a dose-dependent decrease between IL-10 induction and HMGB1 concentration was obviously (P < 0.05). When CD4+ CD25- T cells were cultured with stimulated Tregs, comparing with unstimulated-Treg group, levels of IL-2 and IFN-gamma were elevated following the increased concentration of HMGB1 (P < 0.05 or P < 0.01). Meanwhile the secretion of IL-4 and IL-10 significantly decreased when cultured with stimulated Tregs (P < 0.05). These data suggested that HMGB1 stimulation can result in significant down-regulation of immunosuppression of splenic Tregs in mice. HMGB1 might be a potential immunoregulatory signal that influences the proliferation of effector T cells, secretion of IL-2 and cells-polarization by inhibiting CD4+ CD25+ Tregs activity.

HMG-box domain stimulation of RAG1/2 cleavage activity is metal ion dependent

BackgroundRAG1 and RAG2 initiate V(D)J recombination by assembling a synaptic complex with a pair of antigen receptor gene segments through interactions with their flanking recombination signal sequence (RSS), and then introducing a DNA double-strand break at each RSS, separating it from the adjacent coding segment. While the RAG proteins are sufficient to mediate RSS binding and cleavage in vitro, these activities are stimulated by the architectural DNA binding and bending factors HMGB1 and HMGB2. Two previous studies (Bergeron et al., 2005, and Dai et al., 2005) came to different conclusions regarding whether only one of the two DNA binding domains of HMGB1 is sufficient to stimulate RAG-mediated binding and cleavage of naked DNA in vitro. Here we test whether this apparent discrepancy is attributed to the choice of divalent metal ion and the concentration of HMGB1 used in the cleavage reaction.ResultsWe show here that single HMG-box domains of HMGB1 stimulate RAG-mediated RSS cleavage in a concentration-dependent manner in the presence of Mn2+, but not Mg2+. Interestingly, the inability of a single HMG-box domain to stimulate RAG-mediated RSS cleavage in Mg2+ is overcome by the addition of partner RSS to promote synapsis. Furthermore, we show that mutant forms of HMGB1 which otherwise fail to stimulate RAG-mediated RSS cleavage in Mg2+ can be substantially rescued when Mg2+ is replaced with Mn2+.ConclusionThe conflicting data published previously in two different laboratories can be substantially explained by the choice of divalent metal ion and abundance of HMGB1 in the cleavage reaction. The observation that single HMG-box domains can promote RAG-mediated 23-RSS cleavage in Mg2+ in the presence, but not absence, of partner RSS suggests that synaptic complex assembly in vitro is associated with conformational changes that alter how the RAG and/or HMGB1 proteins bind and bend DNA in a manner that functionally replaces the role of one of the HMG-box domains in RAG-HMGB1 complexes assembled on a single RSS.