Effects Of High Mobility Group Box Research Articles

Postoperative Innate Immune Dysregulation, Proteomic, and Monocyte Epigenomic Changes After Colorectal Surgery: A Substudy of a Randomized Controlled Trial.

Colorectal surgery is associated with moderate-to-severe postoperative complications in over 25% of patients, predominantly infections. Monocyte epigenetic alterations leading to immune tolerance could explain postoperative increased susceptibility to infections. This research explores whether changes in monocyte DNA accessibility contribute to postoperative innate immune dysregulation. Damage-associated molecular patterns (DAMPs) and ex vivo cytokine production capacity were measured in a randomized controlled trial (n = 100) in colorectal surgery patients, with additional exploratory subgroup proteomic (proximity extension assay; Olink) and epigenomic analyses (Assay for Transposase-Accessible Chromatin [ATAC sequencing]). Monocytes of healthy volunteers were used to study the effect of high-mobility group box 1 (HMGB1) and heat shock protein 70 (HSP70) on cytokine production capacity in vitro. Plasma DAMPs were increased after surgery. HMGB1 showed a mean 235% increase from before- (preop) to the end of surgery (95% confidence interval [CI] [166 - 305], P < .0001) and 90% increase (95% CI [63-118], P = .0004) preop to postoperative day 1 (POD1). HSP70 increased by a mean 12% from preop to the end of surgery (95% CI [3-21], not significant) and 30% to POD1 (95% CI [18-41], P < .0001). Nuclear deoxyribonucleic acid (nDNA) increases by 66% (95% CI [40-92], P < .0001) at the end of surgery and 94% on POD1 (95% CI [60-127], P < .0001). Mitochondrial DNA (mtDNA) increases by 370% at the end of surgery (95% CI [225-515], P < .0001) and by 503% on POD1 (95% CI [332-673], P < .0001). In vitro incubation of monocytes with HSP70 decreased cytokine production capacity of tumor necrosis factor (TNF) by 46% (95% CI [29-64], P < .0001), IL-6 by 22% (95% CI [12-32], P = .0004) and IL-10 by 19% (95% CI [12-26], P = .0015). In vitro incubation with HMGB1 decreased cytokine production capacity of TNF by 34% (95% CI [3-65], P = .0003), interleukin 1β (IL-1β) by 24% (95% CI [16-32], P < .0001), and IL-10 by 40% (95% CI [21-58], P = .0009). Analysis of the inflammatory proteome alongside epigenetic shifts in monocytes indicated significant changes in gene accessibility, particularly in inflammatory markers such as CXCL8 (IL-8), IL-6, and interferon-gamma (IFN-γ). A significant enrichment of interferon regulatory factors (IRFs) was found in loci exhibiting decreased accessibility, whereas enrichment of activating protein-1 (AP-1) family motifs was found in loci with increased accessibility. These findings illuminate the complex epigenetic modulation influencing monocytes' response to surgical stress, shedding light on potential biomarkers for immune dysregulation. Our results advocate for further research into the role of anesthesia in these molecular pathways and the development of personalized interventions to mitigate immune dysfunction after surgery.

HMGB1 promotes chemoresistance in small cell lung cancer by inducing PARP1-related nucleophagy

IntroductionSmall cell lung cancer (SCLC) is prone to chemoresistance, which is closely related to genome homeostasis-related processes, such as DNA damage and repair. Nucleophagy is the elimination of specific nuclear substances by cells themselves and is responsible for maintaining genome and chromosome stability. However, the roles of nucleophagy in tumour chemoresistance have not been investigated. ObjectivesThe aim of this work was to elucidate the mechanism of chemoresistance in SCLC and reverse this chemoresistance. MethodsRNA-seq data from SCLC cohorts, chemosensitive SCLC cells and the corresponding chemoresistant cells were used to discover genes associated with chemoresistance and patient prognosis. In vitro and in vivo experiments were performed to verify the effect of high-mobility group box 1 (HMGB1) knockdown or overexpression on the chemotherapeutic response in SCLC. The regulatory effect of HMGB1 on nucleophagy was then investigated by coimmunoprecipitation (co-IP) and mass spectrometry (MS), and the underlying mechanism was explored using pharmacological inhibitors and mutant proteins. ResultsHMGB1 is a factor indicating poor prognosis and promotes chemoresistance in SCLC. Mechanistically, HMGB1 significantly increases PARP1-LC3 binding to promote nucleophagy via PARP1 PARylation, which leads to PARP1 turnover from DNA lesions and chemoresistance. Furthermore, chemoresistance in SCLC can be attenuated by blockade of the PARP1-LC3 interaction or PARP1 inhibitor (PARPi) treatment. ConclusionsHMGB1 can induce PARP1 self-modification, which promotes the interaction of PARP1 with LC3 to promote nucleophagy and thus chemoresistance in SCLC. HMGB1 could be a predictive biomarker for the PARPi response in patients with SCLC. Combining chemotherapy with PARPi treatment is an effective therapeutic strategy for overcoming SCLC chemoresistance.

Glycyrrhizin Attenuates Carcinogenesis by Inhibiting the Inflammatory Response in a Murine Model of Colorectal Cancer.

Glycyrrhizin (GL), an important active ingredient of licorice root, which weakens the proinflammatory effects of high-mobility group box 1 (HMGB1) by blocking HMGB1 signaling. In this study, we investigated whether GL could suppress inflammation and carcinogenesis in an azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced murine model of colorectal cancer. ICR mice were divided into four groups (n = 5, each)—control group, GL group, colon cancer (CC) group, and GL-treated CC (CC + GL) group, and sacrificed after 20 weeks. Plasma levels of interleukin (IL)-6 and tumor necrosis factor (TNF)-α were measured using an enzyme-linked immunosorbent assay. The colonic tissue samples were immunohistochemically stained with DNA damage markers (8-nitroguanine and 8-oxo-7,8-dihydro-2′-deoxy-guanosine), inflammatory markers (COX-2 and HMGB1), and stem cell markers (YAP1 and SOX9). The average number of colonic tumors and the levels of IL-6 and TNF-α in the CC + GL group were significantly lower than those in the CC group. The levels of all inflammatory and cancer markers were significantly reduced in the CC + GL group. These results suggest that GL inhibits the inflammatory response by binding HMGB1, thereby inhibiting DNA damage and cancer stem cell proliferation and dedifferentiation. In conclusion, GL significantly attenuates the pathogenesis of AOM/DSS-induced colorectal cancer by inhibiting HMGB1-TLR4-NF-κB signaling.

16202 Effect of high-mobility group box 1 on keratinocyte and fibroblast and its involvement in the development of psoriasis

Background: Psoriasis is a chronic immune-mediated inflammatory skin disease, in which keratinocyte and fibroblast play an important role. High-mobility group protein B1 (HMGB1) is a nuclear protein that routinely participates in the maintenance of genomic stability and the regulation of gene transcription. HMGB1 is also a physiological activator of immune responses that can be released from keratinocyte and fibroblast nuclei in psoriatic lesions. Although it is implicated in the pathogenesis of autoimmune diseases and cutaneous disorders, the precise role of HMGB1 in psoriasis has yet to be studied.

HMGB1 upregulates NF-kB by inhibiting IKB-α and associates with diabetic retinopathy

AimsDiabetic retinopathy (DR) is the main cause of blindness in adults and investigating new therapeutic targets for DR is necessary. This study aimed to investigate the effect of high-mobility group box 1 (HMGB1) protein and its mechanism in diabetic retinopathy (DR) were investigated. Main methodsHuman retinal endothelial cells (HREC) were uesd for chip-seq. Sprague Dawley (SD) rats were randomly divided into control group, HMGB1 group, diabetes mellitus (DM) combined with HMGB1 siRNA group, and DM group. Next, eyeballs were removed and retinas were detached for western blot. The DM model of cell was built by increasing the glucose concentration in cell culture medium. The regulation of HMGB1 was achieved by short hairpin (sh)-HMGB1 transfection, then, the transfected cells were harvested for luciferase assay, western blot and qRT-PCR analyses as well as proliferation and apoptosis detection. Key findingsChip-seq and luciferase assay showed the possible transcription factor functions of HMGB1 and IKB-α was one of the HMGB1 binding sites. In vivo and in vitro results indicated high expression of HMGB1 and NF-kB and low expression of IKB-α in DR and the expression of IKB-α and NF-kB was regulated by HMGB1. Moreover, cell assays showed that HMGB1 inhibited cell proliferation and promoted apoptosis. SignificanceThe results from the present study showed that HMGB1 may be involved in the pathogenesis of DR as a transcription factor through NF-kB pathway. Therefore, blockade of HMGB1 may be a new method for the treatment of DR.

HMGB3 small interfere RNA suppresses mammosphere formation of MDA-MB-231 cells by down-regulating expression of HIF1α.

Breast cancer has been proven as the most common malignancy influencing the health of females. This research aimed to clarify the effects of high-mobility group box 3 (HMGB3)-small interfere RNA (HMGB3-siRNA) on the proliferation of breast cancer cells. HMGB3-mimic and HMGB3-siRNA lentiviral vectors were structured. The above lentiviral vectors were then transfected into normal breast cells (MCF10A) and breast cancer cells (MDA-MB-231). Cell counting kit-8 (CCK-8) analysis was employed to assess proliferative viabilities of cells. The formation of the mammosphere in breast cancer cells was examined using mammosphere-forming assay. The mRNA expression of Nanog, Sox2, and OCT-4 genes was evaluated using quantitative real time-PCR (qRT-PCR). CD44 positive/CD24 negative (CD44+/CD24-) cell levels were evaluated using flow cytometry assay. The correlation between HMGB3 and hypoxia-inducible factor 1α (HIF1α) was analyzed using Linear-Regression analysis. The interaction between HMGB3 and HIF1α expression was determined using the Dual-Luciferase assay. HMGB3 expression was remarkably enhanced in breast cancer cells compared to that in normal cells (p<0.05). HMGB3-siRNA significantly decreased the proliferative activity and remarkably suppressed the mammosphere formation compared to that in single MDA-MB-231 cells (p<0.05). HMGB3-siRNA remarkably reduced Nanog, SOX2, and OCT-4 and significantly enhanced CD44+/CD24- cells compared to single MDA-MB-231 cells (p<0.05). HMGB3-siRNA significantly weakened the expression of HIF1α in MDA-MB-231 cells compared to single MDA-MB-231 cells (p<0.05). HMGB3 was positively correlated with HIF1α expression (p<0.05). There was an interaction between HMGB expression and HIF1α expression. HMGB3 small interfering RNA suppressed the formation of mammosphere in MDA-MB-231 cells by downregulating the expression of HIF1α.

Antifibrotic Effects of High-Mobility Group Box 1 Protein Inhibitor (Glycyrrhizin) on Keloid Fibroblasts and Keloid Spheroids through Reduction of Autophagy and Induction of Apoptosis

Overabundance of extracellular matrix resulting from hyperproliferation of keloid fibroblasts (KFs) and dysregulation of apoptosis represents the main pathophysiology underlying keloids. High-mobility group box 1 (HMGB1) plays important roles in the regulation of cellular death. Suppression of HMGB1 inhibits autophagy while increasing apoptosis. Suppression of HMGB1 with glycyrrhizin has therapeutic benefits in fibrotic diseases. In this study, we explored the possible involvement of autophagy and HMGB1 as a cell death regulator in keloid pathogenesis. We have highlighted the potential utility of glycyrrhizin as an antifibrotic agent via regulation of the aberrant balance between autophagy and apoptosis in keloids. Higher HMGB1 expression and enhanced autophagy were observed in keloids. The proliferation of KFs was decreased following glycyrrhizin treatment. While apoptosis was enhanced in keloids after glycyrrhizin treatment, autophagy was significantly reduced. The expressions of ERK1/2, Akt, and NF-κB, were enhanced in HMGB1-teated fibroblasts, but decreased following glycyrrhizin treatment. The expression of extracellular matrix (ECM) components was reduced in glycyrrhizin-treated keloids. TGF-β, Smad2/3, ERK1/2, and HMGB1 were decreased in glycyrrhizin-treated keloids. Treatment with the autophagy inhibitor 3-MA resulted in a decrease of autophagy markers and collagen in the TGF-β-treated fibroblasts. The results indicated that autophagy plays an important role in the pathogenesis of keloids. Because glycyrrhizin appears to reduce ECM and downregulate autophagy in keloids, its potential use for treatment of keloids is indicated.

Inhibition of LOX-1 alleviates the proinflammatory effects of high-mobility group box 1 in Aspergillus fumigatus keratitis.

To investigate the inflammatory amplification effect of high-mobility group box 1 (HMGB1) in Aspergillus fumigatus (A. fumigatus) keratitis and the relationship between lectin-like oxidized low-density lipoprotein receptor 1 (LOX-1) and HMGB1 in keratitis immune responses. Phosphate buffer saline (PBS), and Boxb were injected into BALB/c mice subconjunctivally before the corneas were infected with A. fumigatus. RAW264.7 macrophages and neutrophils were pretreated with PBS and Boxb to determine the HMGB1 inflammatory amplification effects. Abdominal cavity extracted macrophages were pretreated with Boxb and Poly (I) (a LOX-1 inhibitor) before A. fumigatus hyphae stimulation to prove the the relationship between the two molecules. LOX-1, interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), macrophage inflammatory protein-2 (MIP-2) and IL-10 were assessed by polymerase chain reaction and Western blot. Pretreatment with Boxb exacerbated corneal inflammation. In macrophages and neutrophils, A. fumigatus induced LOX-1, IL-1β, TNF-α and MIP-2 expression in Boxb group was higher than those in PBS group. Poly (I) treatments before infection alleviated the proinflammatory effects of Boxb in abdominal cavity extracted macrophages. Pretreatment with Boxb did not influence Dectin-1 mRNA levels in macrophages and neutrophils. In fungal keratitis, HMGB1 is a proinflammatory factor in the first line of immune response. HMGB1 mainly stimulates neutrophils and macrophages to produce inflammatory cytokines and chemokines during the immune response. LOX-1 participates in HMGB1 induced inflammatory exacerbation in A. fumigatus keratitis.

Influence of HMGB1/MAPK/m-TOR signaling pathway on cell autophagy and chemotherapy resistance in K562 cells

To observe the effect of high-mobility group box 1 (HMGB1) on autophagy and chemotherapy resistance in human leukemiacell line (K562) cells, and to explore the underlying mechanisms. Methods: The K562 cells were cultured in vitro and divided into 6 groups: a chemotherapeutic group, a chemotherapeutic control group, a HMGB1 preconditioning group, a HMGB1 preconditioning control group, a HMGB1 siRNA group and a siRNA control group. The chemotherapeutic group was further divided into a vincristine (VCR) group, an etoposide (VP-16) group, a cytosine arabinoside (Ara-C) group, a adriamycin (ADM) group and a arsenic trioxide (As2O3) group. The cell activity was evaluated by cell counting kit-8. The protein levels of HMGB1, microtubule-associate protein1light chain3 (LC3), AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (m-TOR) were determined by Western blotting. The level of serum HMGB1 was evaluated by enzyme-linked immunosorbent assay (ELISA). The autophagy was examined by monodansylcadaverine staining and observed under transmission electron microscopy. Results: Compared with the control group, the cell activity was significantly decreased and the level of serum HMGB1 was significantly increased in the chemotherapeutic (VCR, VP-16, Ara-C, ADM and As2O3) groups (all P<0.05). Compared with the control group, the cell activity and the level of serum HMGB1 were significantly increased in the HMGB1 preconditioning group (both P<0.05). Compared with the siRNA control group, the cell activity and the level of serum HMGB1 were significantly decreased in the HMGB1 siRNA group (both P<0.05). Compared with the control group, the expression of LC3-II and the formation of autophagic bodies were increased in the HMGB1 preconditioning group (both P<0.05), the p-AMPK expression was increased and p-mTOR expression was decreased (both P<0.05). Conclusion: HMGB1 can increase the autophagy and promote chemotherapy resistance through the pathway of AMPK/m-TOR in K562 cells.

HMGB1 Enhances Drug Resistance and Promotes In Vivo Tumor Growth of Lung Cancer Cells.

Drug resistance is an obstacle in the chemotherapeutic treatment of lung cancers. In the present study, the effects of high-mobility group box 1 (HMGB1) protein in chemotherapeutic resistance and the relationships between HMGB1 and chemotherapy drug-induced cell apoptosis or necrosis were clarified. We used cisplatin-sensitive A549 cells and cisplatin-resistant A549/DDP cells as cell models with IC50 of 11.58 and 46.95 μM, respectively. A549/DDP had higher level of HMGB1 compared with A549 cells. Interestingly, with the increasing concentration of DDP, HMGB1 was gradually located into cytoplasm in cisplatin-sensitive A549 cells. Moreover, interference with endogenous HMGB1 sensitized the effects of chemotherapeutic drugs, including 5-Fu, DDP, and OXA. Furthermore, results from an in vivo tumorigenesis experiment demonstrated that serum concentration of HMGB1 was much lower in the group inoculated with HMGB1 shRNA-transfected A549 cells than in the N.C. shRNA-transfected A549 inoculated group, as well as the tumor volume, suggesting that serum HMGB1 contributed to tumor growth in a mouse model. In conclusion, higher levels of HMGB1 probably contributed to chemotherapy drug resistance, and higher serum concentration of HMGB1 promoted in vivo tumor growth. The study would provide new clues to overcome drug resistance in chemotherapy of human lung cancers.

The Effect of High-Mobility Group Box 1 in Rat Steatotic and Nonsteatotic Liver Transplantation From Donors After Brain Death.

High-mobility group box 1 (HMGB1) has been described in different inflammatory disorders, and the deleterious effects of brain death (BD) may counteract the protection conferred by ischemic preconditioning (IP), the only surgical strategy that is being applied in clinical liver transplantation. Our study examined how HMGB1 may affect preconditioned and unpreconditioned steatotic and nonsteatotic liver grafts from donors after BD (DBDs) for transplantation. HMGB1 was pharmacologically modulated in liver grafts from DBDs, and HMGB1-underlying mechanisms were characterized. We found that BD decreased HMGB1 in preconditioned and unpreconditioned livers and was associated with inflammation and damage. Exogenous HMGB1 in DBDs activates phosphoinositide-3-kinase and Akt and reduces hepatic inflammation and damage, increasing the survival of recipients. Combination of IP and exogenous HMGB1 shows additional benefits compared with HMGB1 alone. This study provides new mechanistic insights into the pathophysiology of BD-derived liver graft damage and contributes to the development of novel and efficient strategies to ultimately improve liver graft quality.

Effects of high‑mobility group box 1 knockdown on proliferation, migration and invasion of the HONE‑1 human nasopharyngeal carcinoma cell line.

The present study was designed to investigate the effects of high‑mobility group box 1 (HMGB1) knockdown on the proliferation, migration and invasion of the HONE‑1 human nasopharyngeal carcinoma cell line and explore the possible underlying mechanisms. HMGB1-knockdown HONE‑1 cells were generated by lentiviral transfection, and HMGB1 expression was demonstrated to be obviously decreased in these cells. A Cell Counting kit‑8 assay was used to determine cell proliferation, while flow cytometric analysis was employed to determine the apoptotic rate. In addition, in vitro wound healing, cell adhesion and invasion assays were performed to evaluate the metastatic potential of the cells. Western blot analysis was used to determine the protein expression of apoptosis signaling proteins caspase‑3, B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein, receptor for advanced glycation end products (RAGE) as well as phosphorylated and total extracellular signal-regulated kinase 1/2 in HONE‑1 cells. The results of the present study demonstrated that HMGB1 knockdown suppressed the proliferation, migration and invasion of HONE‑1 cells, the mechanisms of which may be associated with the induction of mitochondria‑mediated apoptosis and inhibition of HMGB1/RAGE pathways.

Expression and Effects of High-Mobility Group Box 1 in Cervical Cancer

We investigated the significance of high- mobility group box1 (HMGB1) and T-cell-mediated immunity and prognostic value in cervical cancer. HMGB1, forkhead/winged helix transcription factor p3 (Foxp3), IL-2, and IL-10 protein expression was analyzed in 100 cervical tissue samples including cervical cancer, cervical intraepithelial neoplasia (CIN), and healthy control samples using immunohistochemistry. Serum squamous cell carcinoma antigen (SCC-Ag) was immunoradiometrically measured in 32 serum samples from 37 cases of squamous cervical cancer. HMGB1 and SCC-Ag were then correlated to clinicopathological characteristics. HMGB1 expression tends to increase as cervical cancer progresses and it was found to be significantly correlated to FIGO stage and lymph node metastasis. These findings suggest that HMGB1 may be a useful prognostic indicator of cervical carcinoma. In addition, there were significant positive relationships between HMGB1 and FOXP3 or IL-10 expression (both p < 0.05). In contrast, HMGB1 and IL-2 expression was negatively correlated (p < 0.05). HMGB1 expression may activate Tregs or facilitate Th2 polarization to promote immune evasion of cervical cancer. Elevated HMGB1 protein in cervical carcinoma samples was associated with a high recurrence of HPV infection in univariate analysis (p < 0.05). HMGB1 expression and levels of SCC-Ag were directly correlated in SCC (p < 0.05). Thus, HMGB1 may be a useful biomarker for patient prognosis and cervical cancer prediction and treatment.

The Potential Effect and Mechanism of High-Mobility Group Box 1 Protein on Regulatory T Cell-Mediated Immunosuppression

To investigate the effect of high-mobility group box 1 (HMGB1) protein on the regulatory T cells (Tregs) in vitro and its potential regulating mechanism in mice. Splenic CD4(+)CD25(+) Tregs and CD4(+)CD25(-) T cells were isolated. The time-dependent and dose-dependent responses between HMGB1 stimulation and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) and forkhead/winged helix transcription factor p3 (Foxp3) expressions were analyzed. The secretion of various cytokines in the cell suspensions and the proliferation of CD4(+)CD25(-) T cells were determined. HMGB1 was found to be able to markedly down-regulate the expressions of CTLA-4 and Foxp3, especially at 72 h group and in 1,000 ng/mL group (both P < 0.01). The expression of Foxp3 mRNA showed a similar tendency as Foxp3 protein (P < 0.05 or P < 0.01). The secretion of interleukin (IL)-10 from Tregs was decreased when the concentration of HMGB1 was increased. The suppressive activity of proliferation of CD4(+)CD25(-) T cells exceeded 90% when the ratio of Tregs to CD4(+)CD25(-) T cells was 1:1; meanwhile, the proliferation of CD4(+)CD25(-) T cells was enhanced when cultured with HMGB1-stimulated Tregs. In the culture of HMGB1-stimulated Tregs, IL-2 and interferon-γ levels were elevated; whereas IL-4 and IL-10 decreased in CD4(+)CD25(-) T cells after the increased concentration of HMGB1 in comparison with unstimulated-Treg group. HMGB1 stimulation can result in markedly down-regulatory expressions of CTLA-4 as well as in Foxp3 expression and secretion of IL-10 from splenic Tregs in mice. HMGB1 appears to be involved in modulating cell-mediated immunity by influencing proliferation of effector T cells, secretion of IL-2, and cell polarization.

Hemoperfusion with a high-mobility group box 1 adsorption column can prevent the occurrence of hepatic ischemia–reperfusion injury in rats*

High-mobility group box 1, a ubiquitous nonhistone chromosomal protein, is passively released from necrotic cells and actively secreted by inflammatory cells. Extracellular high-mobility group box 1 has recently been recognized to be a mediator of hepatic ischemia-reperfusion injury; however, the kinetics of high-mobility group box 1 during hepatic ischemia-reperfusion and the role of high-mobility group box 1 in ischemia-reperfusion injury still remain poorly understood. This study was designed to assess the localization and the kinetics of high-mobility group box 1 during hepatic ischemia-reperfusion injury and the effects of high-mobility group box 1 adsorption column in hepatic ischemia-reperfusion injury. A prospective, randomized animal study. University medical center research laboratory. Male Sprague-Dawley rats. The animals underwent 70% partial hepatic ischemia for 60 or 90 mins and were then reperfused. To investigate the high-mobility group box 1 levels in the serum and in the liver, the animals were killed at predetermined periods. As a lethal model, global hepatic ischemia-reperfusion was induced by portal triad cross-clamping for 30 mins. Hemoperfusion therapy using a cellulofine sulfate bead column (high-mobility group box 1 adsorption column) was performed during global hepatic ischemia. During 60 mins of 70% hepatic ischemia, nuclear high-mobility group box 1 was translocated to the cytoplasm in hepatocytes; however, serum high-mobility group box 1was not increased. Immediately after reperfusion, the serum high-mobility group box 1 was significantly increased (p < .05). High-mobility group box 1 mediated ischemia-reperfusion injury in not only liver but also the remote organ, lung. Removal of excess high-mobility group box 1 in blood using an adsorption column significantly improved animal survival (p < .03) and liver and lung injuries. High-mobility group box 1 plays an important role in the systemic as well as local pathogenesis of hepatic ischemia-reperfusion injury. The removal of excessive high-mobility group box 1 with adsorption column was beneficial and promising option in ischemia-related liver injuries.

Protective Effect of HMGB1 A Box on Organ Injury of Acute Pancreatitis in Mice

To investigate the effects of high-mobility group box 1 (HMGB1) A box in experimental severe acute pancreatitis (SAP). Severe acute pancreatitis was induced by 20% L-arginine abdominal cavity injection in Institute of Cancer Research mice, and the treatment group received 2 abdominal cavity injections of A box 12 and 24 hours after the modeling injection. The serum levels of HMGB1, amylase, lipase, and biochemical indicators were measured 24 and 48 hours after induction of SAP. The pathological changes of the pancreas, lung, kidney, and liver for both SAP group and treatment group were observed and compared, as well as survival rate and surviving time. A box significantly improved the elevation of the serum levels of HMGB1, amylase, lipase, and biochemical indicators in SAP. The pathological changes of pancreas and organ injury in treatment group were more alleviated than that in SAP group. The mice survival rate of the treatment group (66.7%) was significantly higher than that of the SAP group (26.7%). A box has remarkable protective effect against pancreatitis and associated organ injury; HMGB1 probably participates in the inflammatory reaction and organ injury of SAP as a late-acting mediator of inflammation.

THE EFFECT OF HIGH-MOBILITY GROUP BOX 1 PROTEIN ON ACTIVITY OF REGULATORY T CELLS AFTER THERMAL INJURY IN RATS

The aim of the present study was to investigate in vivo the effect of high-mobility group box 1 protein (HMGB1) on activity of regulatory T cells (Tregs) and the influence on T-cell-mediated immunity after thermal injury. Male Wistar rats were randomly divided into four groups as follows: sham burn group, burn group, burn with ethyl pyruvate treatment group, and burn with antireceptor for advanced glycation end products (RAGE) antibody treatment group, and they were killed on postburn days 1, 3, 5, and 7, respectively, with eight animals at each time point. Magnetic cell sorting microbeads were used to isolate splenic Tregs and a column of nylon wool to obtain T cells. Phenotypes, including cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), forkhead/winged helix transcription factor p3 (Foxp3), RAGE, and IL-2Ralpha, were analyzed by flow cytometry. Levels of HMGB1, IL-10, IL-2, IL-4 and interferon gamma were determined by enzyme-linked immunosorbent assay kits, and real-time reverse transcription-polymerase chain reaction was performed to detect mRNA expression of IL-10, IL-2, and IL-2Ralpha. Serum HMGB1 levels were significantly elevated during postburn days 1 to 7. In the burn group, CTLA-4 and Foxp3 expression levels of Tregs were strongly enhanced in comparison to the sham-injured group, and the capacity of Tregs to produce IL-10 was markedly increased. Administration of ethyl pyruvate to inhibit HMGB1 or anti-RAGE antibody could significantly decrease expression levels of CTLA-4, Foxp3 on Tregs, and IL-10 production after burns. Simultaneously, proliferative activity and expression levels of IL-2 and IL-2Ralpha of T cell were restored. The excessively released HMGB1 might stimulate CD4+CD25+Treg activity via binding RAGE on the surface of Tregs and trigger a shift of T(H)1 to T(H)2 with suppression of T-lymphocyte immune function after burn injury.

Stopping the Primal RAGE Reaction in Myocardial Infarction

The report of Andrassy and colleagues1 in the current issue of Circulation adds to the growing body of evidence that the receptor for advanced glycation end products (RAGE) and its ligands, particularly high mobility group box-1 (HMGB1), are central mediators of ischemia/reperfusion (I/R) injury in the heart.1–4 A major cause of injury, especially in the reperfusion phase, is the influx of inflammatory cells into the stressed heart. Andrassy and colleagues show that infiltrating leukocytes express proinflammatory HMGB1 and that HMGB1 plays fundamental roles in injury responses in the I/R heart. In homeostasis, HMGB1 is largely a nuclear protein. In stress conditions, HMGB1 may be released from injured cells, particularly on necrosis. The chief receptor for HMGB1, RAGE, is expressed in multiple cell types in the I/R heart, such as inflammatory cells, and also in cardiomyocytes and vascular cells (endothelial cells and smooth muscle cells).2 Although HMGB1 may interact with distinct receptors beyond RAGE (for example, toll receptors),5 the current study of Andrassy and colleagues reveals major roles for RAGE in transducing the effects of HMGB1 in the heart, as administration of recombinant HMGB1 or antagonists of this molecule had significant proinjury effects in the wild-type mouse heart, but no additive effects were noted in mice devoid of RAGE. The biology of RAGE, however, is complex and extends beyond HMGB1 in the injured heart. Article p 3216 In addition to HMGB1, other ligands of RAGE likely play pivotal roles in the response to ischemia or I/R in the heart. For example, rapid generation of pre–advanced glycation end products (AGE) species (methylglyoxal) and AGEs in transient occlusion/reperfusion of the LAD coronary artery has been illustrated.2 In hypoxia, in both the murine heart and in isolated primary murine endothelial cells, AGE-immunoreactive species are central mediators of regulation of …

Negative inotropic effects of high-mobility group box 1 protein in isolated contracting cardiac myocytes

High-mobility group box 1 (HMGB1) released from necrotic cells or macrophages functions as a late inflammatory mediator and has been shown to induce cardiovascular collapse during sepsis. Thus far, however, the effect(s) of HMGB1 in the heart are not known. We determined the effects of HMGB1 on isolated feline cardiac myocytes by measuring sarcomere shortening in contracting cardiac myocytes, intracellular Ca2+ transients by using fluo-3, and L-type calcium currents by using whole cell perforate configuration of the patch-clamp technique. Treatment of isolated myocytes with HMGB1 (100 ng/ml) resulted in a 70% decrease in sarcomere shortening and a 50% decrease in the height of the peak Ca2+ transient within 5 min (P < 0.01). The immediate negative inotropic effects of HMGB1 on cell contractility and calcium homeostasis were partially reversible upon washout of HMGB1. A significant inhibition of the inward l-type calcium currents was also documented by the patch-clamp technique. HMGB1 induced the PKC-epsilon translocation, and a PKC inhibitor significantly attenuated the negative inotropic effects of HMGB1. These studies show for the first time that HMGB1 impairs sarcomere shortening by decreasing calcium availability in cardiac myocytes through modulating membrane calcium influx and suggest that HMGB1 maybe acts as a novel myocardial depressant factor during cardiac injury.