Expression Of High Mobility Group Protein B1 Research Articles

Melatonin relieves neuropathic allodynia through spinal MT2-enhanced PP2Ac and downstream HDAC4 shuttling-dependent epigenetic modification of hmgb1 transcription.

Melatonin (MLT; N-acetyl-5-methoxytryptamine) exhibits analgesic properties in chronic pain conditions. While researches linking MLT to epigenetic mechanisms have grown exponentially over recent years, very few studies have investigated the contribution of MLT-associated epigenetic modification to pain states. Here, we report that together with behavioral allodynia, spinal nerve ligation (SNL) induced a decrease in the expression of catalytic subunit of phosphatase 2A (PP2Ac) and enhanced histone deacetylase 4 (HDAC4) phosphorylation and cytoplasmic accumulation, which epigenetically alleviated HDAC4-suppressed hmgb1 gene transcription, resulting in increased high-mobility group protein B1 (HMGB1) expression selectively in the ipsilateral dorsal horn of rats. Focal knock-down of spinal PP2Ac expression also resulted in behavioral allodynia in association with similar protein expression as observed with SNL. Notably, intrathecal administration with MLT increased PP2Ac expression, HDAC4 dephosphorylation and nuclear accumulation, restored HDAC4-mediated hmgb1 suppression and relieved SNL-sensitized behavioral pain; these effects were all inhibited by spinal injection of 4P-PDOT (a MT2 receptor antagonist, 30 minutes before MLT) and okadaic acid (OA, a PP2A inhibitor, 3 hr after MLT). Our findings demonstrate a novel mechanism by which MLT ameliorates neuropathic allodynia via epigenetic modification. This MLT-exhibited anti-allodynia is mediated by MT2-enhanced PP2Ac expression that couples PP2Ac with HDAC4 to induce HDAC4 dephosphorylation and nuclear import, herein increases HDAC4 binding to the promoter of hmgb1 gene and upregulates HMGB1 expression in dorsal horn neurons.

Prognostic potential of an immune score based on the density of CD8+ T cells, CD20+ B cells, and CD33+/p-STAT1+ double-positive cells and HMGB1 expression within cancer nests in stage IIIA gastric cancer patients.

Objective There is heterogeneity in the prognosis of gastric cancers staged according to the tumornodes- metastasis (TNM) system. This study evaluated the prognostic potential of an immune score system to supplement the TNM staging system. Methods An immunohistochemical analysis was conducted to assess the density of T cells, B cells, and myeloid-derived suppressor cells (MDSCs) in cancer tissues from 100 stage IIIA gastric cancer patients; the expression of the high-mobility group protein B1 (HMGB1) was also evaluated in cancer cells. The relationship between the overall survival (OS), disease-free survival (DFS), and immunological parameters was analyzed. Results An immune score system was compiled based on the prognostic role of the density of T cells, B cells, MDSCs, and the expression of HMGB1 in cancer tissues. The median 5-year survival of this group of patient was 32%. However, the 5-year survival rates of 80.0%, 51.7%, 0%, 5.8%, and 0% varied among the patients with an immune score of 4 to those with an immune score of 0 based on the immune score system, respectively. Similarly, differences in DFS rates were observed among the immune score subgroups. Conclusions An immune score system could effectively identify the prognostic heterogeneity within stage IIIA gastric cancer patients, implying that this immune score system may potentially supplement the TNM staging system, and help in identifying a more homogeneous group of patients who on the basis of prognosis can undergo adjuvant therapy.

HMGB1 Inhibition During Zymosan-Induced Inflammation: The Potential Therapeutic Action of Riboflavin.

Sepsis, also known as systemic inflammatory response syndrome, is a life-threatening condition caused by a pathogenic agent and leading to multiple organ dysfunction syndrome. One of the factors responsible for the excessive intensification of the inflammatory response in the course of inflammation is high-mobility group protein B1 (HMGB1). HMG-1 is a nuclear protein which, after being released to the intercellular space, has a highly pro-inflammatory effect and acts as a late mediator of lethal damage. The purpose of this study was to examine whether the anti-inflammatory action of riboflavin is accompanied by inhibition of HMGB1 release during peritoneal inflammation and zymosan stimulation of macrophages. Peritonitis was induced in male BALB/c and C57BL/6J mice via intraperitoneal injection of zymosan (40 mg/kg). RAW 264.7 macrophages were activated with zymosan (250 µg/ml). Riboflavin (mice, 50 mg/kg; RAW 264.7, 25 µg/ml) was administered 30 min before zymosan, simultaneously with, or 2, 4, 6 h after zymosan. Additionally, mRNA expression of HMGB1 and its intracellular and serum levels were evaluated. The research showed that riboflavin significantly reduces both the expression and the release of HMGB1; however, the effect of riboflavin was time-dependent. The greatest efficacy was found when riboflavin was given 30 min prior to zymosan, and also 2 and 4 h (C57BL/6J; RAW 264.7) or 4 and 6 h (BALB/c) after zymosan. Research showed that riboflavin influences the level of HMGB1 released in the course of inflammation; however, further study is necessary to determine its mechanisms of action.

TNF-α induces the release of high mobility group protein B1 through p38 mitogen-activated protein kinase pathway in microglia

To determine the effect of p38 MAPK inhibitor (SB203580) on TNF-α -induced high mobility group protein B1 (HMGB1) expression in microglial cells. Microglial cells were treated with TNF-α (25 ng/mL, TNF-α group), TNF-α plus SB203580 (10 μmol/L, TNF-α+SB203580 group), SB203580 (SB203580 group) or serum-free medium (control group). After 16 h of incubation, the protein levels of p-p38 MAPK and HMGB1, and mRNA levels of HMGB1 were examined by ELISA, Western Blot and RT-PCR, respectively. There was a significant increase in p-p38 MAPK and HMGB1 levels in TNF-α-treated microglia cells (P<0.01). The TNF-α-induced HMGB1 protein and mRNA expression was suppressed by SB203580. TNF-α up-regulates HMGB1 expression in microglial cells through activation of the p38MAPK pathway.

Tanshinone IIA Attenuates Chronic PancreatitisInduced Pain in Rats via Downregulation of HMGB1 and TRL4 Expression in the Spinal Cord

Background: Chronic pancreatitis (CP) is a long-standing inflammation of the exocrine pancreas, which typically results in severe and constant abdominal pain. Previous studies on the mechanisms underlying CP-induced pain have primarily focused on the peripheral nociceptive system. A role for a central mechanism in the mediation or modulation of abdominal pain is largely unknown. Tanshinone IIA (TSN IIA), an active component of the traditional Chinese medicine Danshen, exhibits anti-inflammatory properties via downregulation of the expression of high-mobility group protein B1 (HMGB1), a late proinflammatory cytokine. HMGB1 binds and activates toll-like receptor 4 (TLR4) to induce spinal astrocyte activation and proinflammatory cytokine release in neuropathic pain. Objective: In this study, we investigated the effect of TSN IIA on pain responses in rats with trinitrobenzene sulfonic acid (TNBS)-induced CP. The roles of central mechanisms in the mediation or modulation of CP were also investigated. Study Design: A randomized, double-blind, placebo-controlled animal trial. Methods: CP was induced in rats by intrapancreatic infusion of trinitrobenzene sulfonic acid (TNBS). Pancreatic histopathological changes were characterized with semi-quantitative scores. The abdomen nociceptive behaviors were assessed with von Frey filaments. The effects of intraperitoneally administered TSN IIA on CP-induced mechanical allodynia were tested. The spinal protein expression of HMGB1 was determined by western blot. The spinal mRNA and protein expression of proinflammatory cytokines IL-1β, TNF-α, and IL-6 were determined by RT-PCR and western blot, respectively. The spinal expression of the HMGB1 receptor TRL4 and the astrocyte activation marker glial fibrillary acidic protein (GFAP) were determined by western blot or immunohistological staining after intraperitoneal injection of TSN IIA or intrathecal administration of a neutralizing anti-HMGB1 antibody. Results: TNBS infusion resulted in pancreatic histopathological changes of chronic pancreatitis and mechanical allodynia in rats. TSN IIA significantly attenuated TNBS-induced mechanical allodynia in a dose-dependent manner. TNBS significantly increased the spinal expression of HMGB1 and proinflammatory cytokines IL-1β, TNF-α, and IL-6. These TNBS-induced changes were significantly inhibited by TSN IIA in a dose-dependent manner. Furthermore, TSN IIA, but not the neutralizing anti-HMGB1 antibody, significantly inhibited TNBS-induced spinal TLR4 and GFAP expression. Limitations: In addition to TLR4, HMGB1 can also bind to toll-like receptor-2 (TLR2) and the receptor for advanced glycation end products (RAGE). Additional studies are warranted to ascertain whether HMGB1 contributes to CP-induced pain through activation of these receptors. Conclusions: Our results suggest that spinal HMGB1 contributes to the development of CPinduced pain and can potentially be a therapeutic target. TSN IIA attenuates CP-induced pain via downregulation of spinal HMGB1 and TRL4 expression. Therefore, TSN IIA may be a potential anti-nociceptive drug for the treatment of CP-induced pain. Key words: Chronic pancreatitis, HMGB1, proinflammatory cytokine, Tanshinone IIA, spinal cord, astrocyte, TLR4

Expression of high mobility group protein-1 in lung tissue of rats with chronic obstructive pulmonary disease

Objective To study the chronic obstructive pulmonary disease(COPD)in rat airway remodeling and high mobility group protein B1(HMGB1)expression level of correlation. Methods Healthy specific pathogen free(SPF)level 48 Wistar male rats, divided into 3 groups,16 rats in each group.Normal saline control group(group A):in 1st,14 d in aseptic operation down neck trachea puncture, to intratracheal injection sterile water for injection 0.2 ml; COPD model group(group B):1st,14d anisotropic intratracheal injection of lipopolysaccharide(LPS)200μg(200μl), 2- 13 d, 15- 28 d every day in selfmade smoked is passive smoking,2 times a day, 10 cigarettes each time, each lasting 60 min, continuous 28 d;smoking cessation group(group C)16:in 1st,14 days to the airway is injected LPS solution 200μg (200μl),2- 13 d,15- 21 d every day in self- made smoked is passive smoking,2 times a day,10 cigarettes each time, each lasting 60 min, continuous 21 d, the last 1 weeks of normal feeding experiments of broken smoke. Observing the pathological changes of rat airway inflammation, airway remodeling and pulmonary tissue after model establishment, with the expression of HMGB1 protein Western in lung tissue of three groups of blot detection. Results The group B, C of airway remodeling index fine bronchial wall thickness and pipe diameter ratio(MT,%)[group B(9.21±3.54), group C(8.23±3.32)], the Guan Bi area and tracheal total area ratio(MA%)[group B(20.25±3.23), group C(17.44±2.57)] and group A[MT,%(4.62±2.58), MA,%(10.72±1.12)] were significantly increased(P< 0.05), compared with C group lower than group B(P<0.05).The Western blot electrophoresis showed that the expression of B and HMGB1 protein levels in group C[group B(1.621±0.254), group C(1.234± 0.327)]compared with group A(0.462±0.581)(P<0.05), significantly enhanced expression of group C than in group B decreased HMGB1 protein(P<0.05). Conclusion With the COPD disease progression of airway remodeling and the expression of HMGB1,enhance the expression of COPD and HMGB1,illustrate the airway remodeling related. Key words: Chronic obstructive pulmonary disease; Airway remodeling; High mobility group protein B1

Association of Upregulated HMGB1 and c-IAP2 Proteins With Hepatocellular Carcinoma Development and Progression.

Background:Hepatocellular carcinoma (HCC) is one of the most important health problems in China.Objectives:This study analyzed expression of high-mobility group protein B1 (HMGB1) and inhibitor of apoptosis protein-2 (c-IAP2) proteins in HCC compared to paired para-tumor tissue samples to assess the association with HCC pathogenesis and progression.Materials and Methods:Sixty-eight HCC and para-tumor tissue samples were collected for Western blot, qRT-PCR and immunohistochemical analyses of HMGB1 and c-IAP2.Results:HMGB1 and c-IAP2 proteins were highly expressed in HCC tissue samples [85.3% (58/68) and 82.4% (56/68), respectively] compared to para-tumor tissue samples [32.3% and 27.9%, respectively]. Furthermore, expression of HMGB1 was significantly associated with enhanced c-IAP2 expression in HCC tissue samples (r = 0.878, P < 0.01). Expression of HMGB1 was associated with tumor multiplicity and size, alpha-fetoprotein (AFP) level and advanced TNM stage, while expression of c-IAP2 was associated with tumor size, AFP level and advanced TNM stage.Conclusions:Expression of HMGB1 and c-IAP2 proteins was associated with HCC development and progression, and the expression of HMGB1 and c-IAP2 proteins in HCC were significantly associated with each other. Additionally, these proteins may show promise as biomarkers to predict HCC progression.

Role of high mobility group protein B-1 in the protective effect of fenofibrate against cardiac hypertrophy

Objective To investigate whether the regulation of high mobility group protein B-1 (HMGB1) by fenofibrate could affect the development of cardiac hypertrophy,and provide a preliminary study mechanism.Methods Primary cultured neonatal rat cardiomyocytes were used as the experimental subjects.The impacts of fenofibrarte on the level of HMGB1 expression and translocation in cardiomyocytes were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting.Cardiac hypertrophy was induced in mice by thoracic transverse aortic constriction.The mice were divided into two groups:experimental group,fenofibrate administration (n =5),and control group,normal saline given (n =5).HMGB1 expression and translocation,as well as the progress of cardiac hypertrophy in the two groups were compared.Results Fenofibrate could down-regulate basal and LPS-stimulated HMGB1 expression (RNA level:P ＜0.05; Protein level:P ＜0.05),as well as the secretion of HMGB1 in cardiomyocytes (P ＜ 0.05).In addition,administration of fenofibrate to mice prevented the development of cardiac hypertrophy induced by thoracic transverse aortic constriction while increased levels of nuclear HMGB1.Conclusion Fenofibrate may inhibit the development of cardiac hypertrophy by regulating HMGB1 expression,which provides a new potential strategy to treat cardiac hypertrophy. Key words: Peroxisome proliferator activated receptor α; Fenofibrate; High mobility group protein B-1 ; Cardiomyocytes; Cardiac hypertrophy

High-mobility group protein B1 (HMGB1) and its potential in diagnosis and treatment of ovarian cancer

Objective: The objective of this research is to study the serum level of the high-mobility group protein B1 (HMGB1) in human ovarian tumor (OvCa) and in a healthy control. This study also aims to identify different HMGB1 levels before and after surgery and to explore the inhibitory effect of HMGB1 gene silencing in the proliferation and invasion ability of OvCa. Methods: Enzyme-linked immunosorbent assay was used to measure the serum level of HMGB1 in OvCa patients and healthy subjects. Lentivirus vector with HMGB1 shRNA was constructed and used to infect OvCa cells. The expressions of HMGB1 mRNA and protein were tested by real-time PCR and Western blot. Cell proliferation was detected using the Cell Counting Kit-8 assay, whereas cell invasion and migration were detected by Transwell assay. Results: The serum level of HMGB1 was more elevated in patients with malignant diseases compared with individuals with benign diseases and the control groups. In the malignant group, the serum level of HMGB1 decreased noticeably after therapy. Down-regulation of HMGB1 expression resulted in the inhibition of the biological behavior and metastasis of ovarian cancer cells. Conclusion: HMGB1 is closely associated with clinicopathologic features of OvCa. Knockdown of HMGB1 expression can significantly inhibit cell proliferation, cell migration, and cell invasion of OvCa. These findings indicate that HMGB1 can function as a therapeutic target for ovarian neoplasm in the future.

Increased Expression of High-Mobility Group Protein B1 in Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is an inflammation of the sinonasal mucosa and many inflammatory cells and cytokines are involved in its pathogenesis. High-mobility group protein B1 (HMGB1) is a DNA-binding protein that has a proinflammatory function when secreted into extracellular space. The purpose of this study was to evaluate the expression of HMGB1 in paranasal sinus mucosa and to determine the difference of HMGB1 expression between CRS patients and normal controls. Paranasal sinus mucosa was obtained from 10 patients with CRS and 10 patients without CRS. Semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR), real-time PCR and Western blot analysis were performed to detect mRNA and protein. Sections of the mucosa were immunostained for localization of HMGB1 and image analysis was performed. RT-PCR and real-time PCR showed that the expression level of HMGB1 mRNA was significantly increased in the tissues of patients with CRS compared with controls. Western blot analysis showed that the expression level of HMGB1 protein was significantly increased in the tissues of CRS. In immunohistochemical staining, the HMGB1 protein was expressed in epithelial cells and inflammatory cells and the expression intensity of HMGB1 protein was stronger in CRS. HMGB1 is increased in the paranasal sinus mucosa of patients with CRS. These results suggest a possible contribution of HMGB1 in the pathophysiology of CRS.

Overexpression of high mobility group protein B1 correlates with the proliferation and metastasis of lung adenocarcinoma cells

High mobility group protein B1 (HMGB1) plays an important role in a number of clinical conditions, such as autoimmunity, cardiovascular disease and cancer. Evidence suggests that HMGB1 is critical in the development and progression of numerous types of tumor. However, the underlying molecular mechanisms for the HMGB1-mediated progression and metastasis of lung cancer have not yet been elucidated. In this study, we investigated the role of HMGB1 in lung adenocarcinoma and the mechanisms by which it contributes to carcinogenesis and metastasis. We demonstrated that there was an increase in the expression of HMGB1 in primary cancer tissues compared to the matched adjacent non-cancerous tissues. The expression levels of TOB1 in the normal human bronchial epithelial (HBE) cell line and 10lung cancer cell lines were determined by reverse transcription-PCR (RT-PCR). The results revealed that HMGB1 expression increased in 8cell lines compared with the HBE cell line. The A549 and NCI-H1975cells were transfected with HMGB1 recombinant plasmid. We discovered that the overexpression of HMGB1 promoted cell growth and metastasis in the 2cell lines. Further investigation revealed that exogenously expressed HMGB1 enhanced the activation of p38 and Erk1/2, in addition to the expression of nuclear factor (NF)-κB. We propose that HMGB1 functions as a tumor promoter and that it regulates the proliferation and invasion of lung cancer cells by modulating the activation of the Erk1/2 and p38 mitogen-activated protein kinase (MAPK) signaling pathways.

Expression of HMGB1 and NF-κB p65 and its significance in non-small cell lung cancer

Aim of the studyTo study high mobility group protein B1 (HMGB1) and nuclear transcription factor p65 (NF-κB p65) expression in non-small cell lung cancer and its significance.Material and methods106 hospitalized patients with non-small cell lung cancer after thoracic surgery were enrolled; HMGB1 and p65 protein expression was detected by the immunohistochemical method. Semiquantitative expression of HMGB1 and NF-κB p65 was analyzed using Image Pro Plus (IPP) software and statistical analysis.ResultsThe rate of HMGB1 positive expression in the non-small cell lung cancer protein B1 family was significantly higher than normal tissues (P < 0.05); p65 protein expression in the non-small cell lung carcinoma group was significantly higher than that of normal tissues (P < 0.05). HMGB1 and NF-κB p65 protein expression was significantly higher compared with the non-metastatic group (P < 0.01). HMGB1 and NF-κB p65 protein expression showed a positive correlation (P < 0.05).ConclusionsHMGB1 and NF-κB p65 expression may be related to non-small cell lung cancer metastasis.

Effect of NF-κB inhibitor on high-mobility group protein B1 expression in a COPD rat model

The aim of the present study was to investigate the effect of the nuclear factor‑κB (NF‑κB) inhibitor, pyrrolidine dithiocarbamate (PDTC), on high‑mobility group protein B1 (HMGB1) expression in a rat model of chronic obstructive pulmonary disease (COPD). The COPD model was developed by administering lipopolysaccharides to the airways of rats and smudging (group B). In addition, a model of COPD complicated with hypoxia was established by administering lipopolysaccharides to the airways of rats, smudging and hypoxia (group C). PDTC was administered to the treatment groups by intraperitoneal injection. Reverse transcription polymerase chain reaction (RT‑PCR) and western blot analysis were used to detect the expression of HMGB1 and NF‑κB in lung tissue. RT‑PCR and western blot analysis demonstrated that HMGB1 mRNA and protein expression in groups B and C increased significantly (P<0.05) compared with control group A. In addition, HMGB1 expression in groups B and C gradually increased. HMGB1 mRNA and protein expression in groups B1 and C1 decreased (P<0.05) compared with B and C. NF‑κB protein expression in groups B and C increased significantly (P<0.05) compared with A. NF‑κB protein expression in groups B1 and C1 decreased compared with B and C. Therefore, HMGB1 mRNA and protein expression was identified to be positively correlated with NF‑κB protein expression. The NF‑κB inhibitor, PDTC, was demonstrated to significantly inhibit HMGB1 expression in lung tissues of rats with COPD and this mechanism may be associated with the NF‑κB signal transduction pathway.

RETRACTED: High-mobility group protein B1 (HMGB1) is a novel biomarker for human ovarian cancer

High mobility group box l (HMGB1), a nuclear and extracellular protein, is implicated in some physiologic and pathologic conditions. In this study, we investigated the expression and function of HMGB1 in ovarian cancer. cDNA microarray analysis was performed to compare gene expression profiles of the highly invasive and the low invasive subclones derived from the SKOV3 human ovarian cancer cell line. Immunohistochemistry (IHC) staining was performed to investigate HMGB1 expression in a total of 100 ovarian tissue specimens. In functional assays, effects of HMGB1 knockdown on the biological behavior of ovarian cancer cells were investigated. HMGB1 was overexpressed in the highly invasive subclone compared with the low invasive subclone. High HMGB1 expression was associated with poor clinicopathologic features. Knockdown of HMGB1 expression significantly suppressed ovarian cancer cell proliferation accompanied by decreased cyclin D1 and PCNA expression, and inhibited cell migration and invasion accompanied by decreased MMP2 and MMP9 activities. HMGB1 is a newly identified gene overexpressed in ovarian cancer and associated with poor clinicopathologic features. HMGB1 may serve as a new biomarker and a therapeutic target for ovarian cancer in the future.

The effect of HMGB1 A box on lung injury in mice with acute pancreatitis

The objective of this study is to observe the effect of high-mobility group protein B1 A Box (HMGB1 A) box on lung injury in mice with acute pancreatitis and its effect on the level of high-mobility group protein B1 (HMGB1) in lung, to explore the mechanism. A total of 60 male Institute of Cancer Research mice were randomly divided into control group (n = 30) and treatment group (n = 30). Severe acute pancreatitis mice model was induced by 20% L-Arg intraperitoneal injection. The recombination HMGB1 A box was used in treatment after modeling. All the mice were killed under anesthesia at 24 and 48 h after the modeling injection. The level of HMGB1 and activity of myeloperoxidase (MPO) in lung were measured. The pathological changes of lung were observed. The level of HMGB1 in lung of A box treatment group decreased more significantly 24 h and 48 h after modeling compared with control group. The activity of MPO in lung of A box treatment group decreased more significantly 24 h after modeling compared with control group. The lung tissue pathologic score of A box treatment group decreased more significantly 48 h after modeling compared with control group. HMGB1 expression levels in the lungs were positively related to histological score of injured lung in acute pancreatitis. It indicates that HMGB1 A box is remarkably protective to lung injury induced by acute pancreatitis.

LPS Induces HMGB1 Relocation and Release by Activating the NF-κB-CBP Signal Transduction Pathway in the Murine Macrophage-Like Cell Line RAW264.7

High mobility group protein B1 (HMGB1) is an important late inflammatory mediator in sepsis. Understanding the mechanisms that regulate HMGB1 release from cells and their downstream signal transduction pathways may lead to the ability to develop anti-HMGB1 therapies to treat inflammation. We stimulated murine macrophage-like RAW 264.7 cells with lipopolysaccharide (LPS) and LPS+ ethylpyruvate (EP) and examined the resulting HMGB1 expression and release. We also studied the expression of related signal transduction factors (NF-κB, p38 MAPK, and CBP). Gene expression of HMGB1 mRNA in RAW264.7 cell showed no significant change at 0-18 h after stimulation with LPS, but increased significantly at 24, 36, and 48 h. HMGB1 mRNA expression in the LPS+EP group was significantly lower than in LPS alone. HMGB1 was distributed mainly in the nucleus; the cytoplasmic level was low before LPS stimulation. After stimulation with LPS, cytoplasmic HMGB1 increased gradually and plateaued at a high level at 12-48 h. Nuclear HMGB1 decreased gradually at 12-24 h, then increased, maintaining a comparatively high level at 36-48 h. EP prevented this pattern significantly. LPS induced p38 MAPK activation and NF-κB signal pathways first, followed by CBP activation. Activated CBP acetylated HMGB1 was stored in a crino-lysosome and secreted activated NF-κB resulted in increased transcription and synthesis of HMGB1, but the expression of up-regulated HMGB1 mRNA was delayed. Extracellular HMGB1 originated from early synthetic reserves present in the nucleus. New HMGB1 protein was synthesized in the nucleus and transferred into the cytoplasm, causing an increase in HMGB1 in the nucleus and cytoplasm. EP inhibits HMGB1 mRNA up-regulation and release from LPS- stimulated macrophages. The molecular function of EP is to attenuate the activation p38 MAPK, NF-κB, and CBP signaling pathways.

High Mobility Group Protein Bl (HMGB1) in Asthma: Comparison of Patients with Chronic Obstructive Pulmonary Disease and Healthy Controls

High mobility group protein B1 (HMGB1) has been implicated as an important mediator in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD). However, the expression of HMGB1 in plasma and sputum of patients with asthma and COPD across disease severity needs to be defined. The objective of the study was to examine the induced sputum and plasma concentrations of HMGB1 in COPD and asthmatic patients to determine differences in HMGB1 levels between these diseases and their relationship with airway obstruction and inflammatory patterns. A total of 147 participants were enrolled in this study. The participants included 34 control subjects, 61 patients with persistent asthma (according to the Global Initiative for Asthma [GINA] guidelines) and 47 patients with stable COPD (stratified by Global Initiative for Chronic Obstructive Lung Disease [GOLD] status). Spirometry was performed before sputum induction. HMGB1 levels in induced sputum and plasma were determined by enzyme-linked immunosorbent assay. Sputum and plasma concentrations of HMGB1 in patients with asthma and COPD were significantly higher than concentrations in control subjects and were significantly negatively correlated with forced expiratory volume in 1 s (FEV(1)), FEV(1) (% predicted) in all 147 participants. The levels of HMGB1 in induced sputum of COPD patients were significantly higher than those of asthma patients and healthy controls (P < 0.001). This difference was present even after adjusting for sex, age, smoking status, daily dose of inhaled corticosteroids and disease severity. There were no significant differences in HMGB1 levels between patients with eosinophilic and noneosinophilic asthma. HMGB1 levels in asthmatic and COPD patients were positively correlated with neutrophil counts and percentage of neutrophils. In multivariate analysis, the two diseases (asthma and COPD) and disease severity were independent predictors of sputum HMGB1, but not smoking, age or use of inhaled corticosteroids. In conclusion, these data support a potential role for HMGB1 as a biomarker and diagnostic tool for the differential diagnosis of asthma and COPD. The importance of this observation on asthma and COPD mechanisms and outcomes should be further investigated in large prospective studies.

Expression of high mobility group protein B1 in the lungs of rats with sepsis.

Vibrio vulnificus inside the body could activate the NF-κB signaling pathway and initiate the inflammatory cascade. The lung is one of the earliest organs affected by sepsis associated with acute lung injury. High mobility group protein B1 (HMGB1) is an important late-acting pro-inflammatory cytokine involving in the pathophysiology of sepsis. It is also involved in the injury process in the lung, liver and intestine. There has been no report on the involvement of HMGB1 in Vibrio vulnificus sepsis-induced lung injury. Sixty rats were randomly divided into a normal control group (group A, n=10) and a Vibrio vulnificus sepsis group (group B, n=50). Sepsis was induced in the rats by subcutaneous injection of Vibrio vulnificus (concentration 6×10(8) cfu/mL, volume 0.1 mL/100g)) into the left lower limbs. The rats in group B were sacrificed separately 1, 6, 12, 24, and 48 hours after the infection. Their lungs were stored as specimens, lung water content was measured, and lung pathology was observed under a light microscope. The expressions of the HMGB1 gene and protein in the lungs were detected by RT-PCR and Western blot. Data were analyzed with one-way analysis of variance (ANOVA) and the LSD method for pair-wise comparison between the two groups. P<0.05 was considered statistically significant. Compared to group A (0.652±0.177), HMGB1 mRNA expression in the lungs of group B was significantly higher at 0 hour (1.161±0.358, P=0.013), 24 hours (1.679±0.235, P=0.000), and 48 hours (1.258±0.274, P=0.004) (P<0.05), and peaked at 24 hours. Compared to group A (0.594±0.190), HMGB1 protein expression at 6 hours (1.408±0.567, P=0.026) after infection was significantly increased (P<0. 05), and peaked at 24 hours (2.415±1.064, P=0.000) after infection. Compared to group A (0.699±0.054), lung water content was significantly increased at 6 hours (0.759±0.030, P=0.001),12 hours (0.767±0.023, P=0.000), 24 hours (0.771±0.043, P=0.000) and 48 hours (0.789±0.137, P=0.000) after infection (P<0.05). Compared to group A, pathological changes at 12 hours in group B indicate marked pulmonary vascular congestion, interstitial edema and inflammatory infiltration. Alveolar cavity collapse and boundaries of the alveolar septum could not be clearly identified. Vibrio vulnificus sepsis can lead to injury in rat lungs, and increased HMGB1 expression in lung tissue may be one of the mechanisms for injury from Vibrio vulnificus sepsis.

High Mobility Group Protein-B1 Interacts with Sterol Regulatory Element-binding Proteins to Enhance Their DNA Binding

Sterol regulatory element-binding proteins (SREBPs) are transcription factors that are predominately involved in the regulation of lipogenic and cholesterogenic enzyme gene expression. To identify unknown proteins that interact with SREBP, we screened nuclear extract proteins with 35S-labeled SREBP-1 bait in Far Western blotting analysis. Using this approach, high mobility group protein-B1 (HMGB1), a chromosomal protein, was identified as a novel SREBP interacting protein. In vitro glutathione S-transferase pull-down and in vivo coimmunoprecipitation studies confirmed an interaction between HMGB1 and both SREBP-1 and -2. The protein-protein interaction was mediated through the helix-loop-helix domain of SREBP-1, residues 309-344, and the A box of HMGB1. Furthermore, an electrophoretic mobility shift assay demonstrated that HMGB1 enhances SREBPs binding to their cognate DNA sequences. Moreover, luciferase reporter analyses, including RNA interference technique showed that HMGB1 potentiates the transcriptional activities of SREBP in cultured cells. These findings raise the intriguing possibility that HMGB1 is potentially involved in the regulation of lipogenic and cholesterogenic gene transcription.