Eukaryotic chromatin consisting of nucleosomes connected by linker DNA is organized into higher order structures,which is facilitated by linker histone H1.Formation of chromatin compacts and protects the genome,but al...Eukaryotic chromatin consisting of nucleosomes connected by linker DNA is organized into higher order structures,which is facilitated by linker histone H1.Formation of chromatin compacts and protects the genome,but also hinders DNA transactions.Cells have evolved mechanisms to modify/remodel chromatin resulting in chromatin states suitable for genome functions.The high mobility group box(HMGB)proteins are non-histone chromatin architectural factors characterized by one or more HMGB motifs that bind DNA in a sequence nonspecific fashion.They play a major role in chromatin dynamics.The Saccharomyces cerevisiae(yeast hereafter)HMGB protein Hmo1 contains two HMGB motifs.However,unlike a canonical HMGB protein that has an acidic C-terminus,Hmo1 ends with a lysine rich,basic,C-terminus,resembling linker histone H1.Hmo1 exhibits characteristics of both HMGB proteins and linker histones in its multiple functions.For instance,Hmo1 promotes transcription by RNA polymerases I and II like canonical HMGB proteins but makes chromatin more compact/stable like linker histones.Recent studies have demonstrated that Hmo1 destabilizes/disrupts nucleosome similarly as other HMGB proteins in vitro and acts to maintain a common topological architecture of genes in yeast genome.This minireview reviews the functions of Hmo1 and the underlying mechanisms,highlighting recent discoveries.展开更多
Opioids,such as morphine,are the most potent drugs used to treat pain.Long-term use results in high tolerance to morphine.High mobility group box-1(HMGB1) has been shown to participate in neuropathic or inflammatory p...Opioids,such as morphine,are the most potent drugs used to treat pain.Long-term use results in high tolerance to morphine.High mobility group box-1(HMGB1) has been shown to participate in neuropathic or inflammatory pain,but its role in morphine tolerance is unclear.In this study,we established rat and mouse models of morphine tolerance by intrathecal injection of morphine for 7 consecutive days.We found that morphine induced rat spinal cord neurons to release a large amount of HMGB1.HMGB1 regulated nuclear factor κB p65 phosphorylation and interleukin-1β production by increasing Toll-like receptor 4receptor expression in microglia,thereby inducing morphine tolerance.Glycyrrhizin,an HMGB1 inhibito r,markedly attenuated chronic morphine tole rance in the mouse model.Finally,compound C(adenosine 5’-monophosphate-activated protein kinase inhibitor) and zinc protoporphyrin(heme oxygenase-1 inhibitor)alleviated the morphine-induced release of HMGB1 and reduced nuclear factor κB p65 phosphorylation and interleukin-1β production in a mouse model of morphine tolerance and an SH-SY5Y cell model of morphine tole rance,and alleviated morphine tolerance in the mouse model.These findings suggest that morphine induces HMGB1 release via the adenosine 5’-monophosphate-activated protein kinase/heme oxygenase-1 signaling pathway,and that inhibiting this signaling pathway can effectively reduce morphine tole rance.展开更多
BACKGROUND: Liver failure in chronic hepatitis B (CHB) patients is a severe, life-threatening condition. Intestinal endotoxemia plays a significant role in the progress to liver failure. High mobility group box-1 (HMG...BACKGROUND: Liver failure in chronic hepatitis B (CHB) patients is a severe, life-threatening condition. Intestinal endotoxemia plays a significant role in the progress to liver failure. High mobility group box-1 (HMGB1) protein is involved in the process of endotoxemia. Regulatory T (Treg) cells maintain immune tolerance and contribute to the immunological hyporesponsiveness against HBV infection. However, the roles of HMGB1 and Treg cells in the pathogenesis of liver failure in CHB patients, and whether HMGB1 affects the immune activity of Treg cells are poorly known at present, and so were explored in this study. METHODS: The levels of HMGB1 expression were detected by ELISA, real-time RT-PCR, and Western blotting, and the percentage of CD4(+)CD25(+)CD127(low) Treg cells among CD4(+) cells was detected by flow cytometry in liver failure patients with chronic HBV infection, CHB patients, and healthy controls. Then, CD4(+)CD25(+)CD127(low) Treg cells isolated from the peripheral blood mononuclear cells from CHB patients were stimulated with HMGB1 at different concentrations or at various intervals. The effect of HMGB1 on the immune activity of Treg cells was assessed by a suppression assay of the allogeneic mixed lymphocyte response. The levels of forkhead box P3 (Foxp3) expression in Treg cells treated with HMGB1 were detected by RT-PCR and Western blotting. RESULTS: A higher level of HMGB1 expression and a lower percentage of Treg cells within the population of CIA(+) cells were found in liver failure patients than in CHB patients (82.6+/-20.1 mu g/L vs. 34.2+/-13.7 mu g/L; 4.55+/-1.34% vs. 9.52+/-3.89%, respectively). The immune activity of Treg cells was significantly weakened and the levels of Foxp3 expression were reduced in a dose- or time-dependent manner when Treg cells were stimulated with HMGB1 in vitro. CONCLUSIONS: The high level of HMGB1 and the low percentage of Treg cells play an important role in the pathogenesis of liver failure in patients with chronic HBV infection. Moreover, HMGB1 can weaken the immune activity of Treg cells. It is suggested that effectively inhibiting HMGB1 expression could be a feasible way to treat liver failure by suppressing endotoxemia and enhancing Treg cell activity.展开更多
Objective This study was performed to investigate the effect of high mobility group box-1 protein(HMGB1)on immune function of human T lymphocytes in vitro and explore its potential role in cell-mediated immune dysfunc...Objective This study was performed to investigate the effect of high mobility group box-1 protein(HMGB1)on immune function of human T lymphocytes in vitro and explore its potential role in cell-mediated immune dysfunction.Methods Fresh blood was obtained from healthy adult volunteers and peripheral blood mononuclear cells(PBMCs)were isolated,then rhHMGB1 was added to PBMCs.Four-color flow cytometric(FCM)analysis was used for the measurement of intracellular cytokine including interleukin IL-4 and interferon IFN-?ELISA kits were employed for the determination of IL-2 and sIL-2R protein levels in cell culture supernatants.Results(1)Different stimulating time and dosage of rhHMGB1 did not alter the number of IFN-αpositive cells(Th1).rhHMGB1 stimulation provoked a dose-dependent and time-dependent increase in Th2 subset and decrease in ratio of Th1 to Th2.(2)Compared with the untreated cells,when the cells were coincubated with rhHMGB1(10-100ng/ml)for 12 hrs,protein release of IL-2 and sIL-2R were significantly up-regulated.At 48 hrs,in contrast,protein production was relatively lower in cells after exposure to 100-1000 ng/ml rhHMGB1.Conclusions These findings demonstrated that HMGB1 has a dual influence on immune functions of human T lymphocytes.展开更多
Sepsis is an infection induced systemic inflammatory response syndrome and is a major cause of morbidity as well as mortality in intensive care units. A growing body of evidence suggests that the activation of a proin...Sepsis is an infection induced systemic inflammatory response syndrome and is a major cause of morbidity as well as mortality in intensive care units. A growing body of evidence suggests that the activation of a proinflammatory cascade is responsible for the development of immune dysfunction, susceptibility to severe sepsis and septic shock. The present theories of sepsis as a dysregulated inflammatory response and immune function, as manifested by excessive release of inflammatory mediators such as high mobility group box 1 protein （HMGB1）, are supported by increasing studies employing animal models and clinical observations of sepsis. HMGB1, originally described as a DNA-binding protein and released passively by necrotic cells and actively by macrophages/monocytes, has been discovered to be one of essential cytokines that mediates the response to infection, injury and inflammation. A growing number of studies still focus on the inflammation-regulatory function and its contribution to infectious and inflammatory disorders, recent data suggest that HMGB1 formation can also markedly influence the host cell-mediated immunity, including T lymphocytes and macrophages. Here we review emerging evidence that support extracellular HMGB1 as a late mediator of septic complications, and discuss the therapeutic potential of several HMGBl-targeting agents in experimental sepsis. In addition, with the development of traditional Chinese medicine in recent years, it has been proven that traditional Chinese herbal materials and their extracts have remarkable effective in treating severe sepsis. In this review, we therefore provide some new concepts of HMGBl-targeted Chinese herbal therapies in sepsis.展开更多
High mobility group box-1 protein(HMGB1),which is a nuclear protein,participates in chromatin architecture and transcriptional regulation.When released from cells,HMGB1 also plays a well-established role as a pro-infl...High mobility group box-1 protein(HMGB1),which is a nuclear protein,participates in chromatin architecture and transcriptional regulation.When released from cells,HMGB1 also plays a well-established role as a pro-inflammatory mediator during innate immune responses to injury.In the initial stage of injury,there is a release of large quantities of early pro-inflammatory mediators to initiate or perpetuate immune responses against pathogens,but this pro-inflammatory period is transient,and it is followed by a prolonged period of immune suppression.At present,several lines of evidences have suggested that HMGB1 is a late cytokine provoking delayed endotoxin morbidity,which may enhance the production of early proinflammatory mediators,and it can contribute potently to the activation of different immune cells and play a role in the development of host cell-mediated immunity.The biology of HMGB1 has been extensively studied as a pro-inflammatory cytokine of systemic inflammation,however,this review will attempt to provide a summary of the effects of HMGB1 on different immune cells and its regulatory mechanism in acute insults.展开更多
The high mobility group box 1(HMGB1),which belongs to the subfamily of HMG-1/-2,is a highly conserved single peptide chain consisting of 215 amino acid residues with a molecular weight of approximately 24894 Da.HMGB1 ...The high mobility group box 1(HMGB1),which belongs to the subfamily of HMG-1/-2,is a highly conserved single peptide chain consisting of 215 amino acid residues with a molecular weight of approximately 24894 Da.HMGB1 is a ubiquitous nuclear protein in mammals and plays a vital role in inflammatory diseases.Acute pancreatitis is one of the most common causes of acute abdominal pain with a poor prognosis.Acute pancreatitis is an acute inflammatory process of the pancreas(duration of less than six months),for which the severe form is called severe acute pancreatitis(SAP).More and more studies have shown that HMGB1 has a bidirectional effect in the pathogenesis of SAP.Extracellular HMGB1 can aggravate the pancreatic inflammatory process,whereas intracellular HMGB1 has a protective effect against pancreatitis.The mechanism of HMGB1 is multiple,mainly through the nuclear factor-κB pathway.Receptors for advanced glycation endproducts and toll-like receptors(TLR),especially TLR-2 and TLR-4,are two major types of receptors mediating the inflammatory process triggered by HMGB1 and may be also the main mediators in the pathogenesis of SAP.HMGB1 inhibitors,such as ethyl pyruvate,pyrrolidine dithiocarbamate and Scolopendra subspinipes mutilans,can decrease the level of extracellular HMGB1 and are the promising targets in the treatment of SAP.展开更多
High mobility group box 1 protein （HMGB1） is a highly conserved, ubiquitous protein in the nuclei and cytoplasm of nearly all cell types. HMGB1 is secreted into the extracellular milieu and acts as a proinflammatory...High mobility group box 1 protein （HMGB1） is a highly conserved, ubiquitous protein in the nuclei and cytoplasm of nearly all cell types. HMGB1 is secreted into the extracellular milieu and acts as a proinflammatory cytokine. In this article we reviewed briefly the cellular immune response mediated by HMGB1 in inflammation and sepsis. This systemic review is mainly based on our own work and other related reports HMGB1 can actively affect the immune functions of many types of cells including T lymphocytes, regulatory T cells （Tregs）, dendritic cells （DCs）, macrophages, and natural killer cells （NK cells）. Various cellular responses can be mediated by HMGB1 which binds to cell-surface receptors [e.g., the receptor for advanced glycation end products （RAGE）, Toll-like receptor （TLR）2, and TLR4]. Anti-HMGB1 treatment, such as anti-HMGB1 polyclonal or monoclonal antibodies, inhibitors （e.g., ethyl pyruvate） and antagonists （e.g., A box）, can protect against sepsis lethality and give a wider window for the treatment opportunity. HMGB1 is an attractive target for the development of new therapeutic strategies in the treatment of patients with septic complications.展开更多
BACKGROUND： Vibrio vulnifi cus inside the body could activate the NF-!B signaling pathwayand initiate the inflammatory cascade. The lung is one of the earliest organs affected by sepsisassociated with acute lung inju...BACKGROUND： Vibrio vulnifi cus inside the body could activate the NF-!B signaling pathwayand initiate the inflammatory cascade. The lung is one of the earliest organs affected by sepsisassociated with acute lung injury. High mobility group protein B1 （HMGB1） is an important late-actingpro-infl ammatory cytokine involving in the pathophysiology of sepsis. It is also involved in the injuryprocess in the lung, liver and intestine. There has been no report on the involvement of HMGB1 inVibrio vulnifi cus sepsis-induced lung injury.METHODS： Sixty rats were randomly divided into a normal control group （group A, n=10） anda Vibrio vulnificus sepsis group （group B, n=50）. Sepsis was induced in the rats by subcutaneousinjection of Vibrio vulnificus （concentration 6×108 cfu/mL, volume 0.1 mL/100g）） into the left lowerlimbs. The rats in group B were sacrifi ced 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 wasobserved under a light microscope. The expressions of the HMGB1 gene and protein in the lungswere 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 wasconsidered statistically signifi cant.RESULTS： Compared to group A （0.652±0.177）, HMGB1 mRNA expression in the lungs ofgroup B was signifi cantly 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 wassignificantly 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 48hours （0.789±0.137, P=0.000） after infection （P〈0.05）. Compared to group A, pathological changesat 12 hours in group B indicate marked pulmonary vascular congestion, interstitial edema andinfl ammatory infi ltration. Alveolar cavity collapse and boundaries of the alveolar septum could not beclearly identifi ed.CONCLUSION： Vibrio vulnifi cus sepsis can lead to injury in rat lungs, and increased HMGB1expression in lung tissue may be one of the mechanisms for injury from Vibrio vulnifi cus sepsis.展开更多
High mobility group protein 1(HMGB1) is a multifunctional protein that interacts with DNA and chromatin to influence the regulation of transcription, DNA replication and repair and recombination. We show that HMGB1 al...High mobility group protein 1(HMGB1) is a multifunctional protein that interacts with DNA and chromatin to influence the regulation of transcription, DNA replication and repair and recombination. We show that HMGB1 alters the structure and stability of the canonical nucleosome(N) in a nonenzymatic,adenosine triphosphate-independent manner. As a result, the canonical nucleosome is converted to two stable, physically distinct nucleosome conformers. Although estrogen receptor(ER) does not bind to its consensus estrogen response element within a nucleosome, HMGB1 restructures the nucleosome to facilitate strong ER binding. The isolated HMGB1-restructured nucleosomes(N' and N'') remain stable and exhibit a number of characteristics that are distinctly different from the canonical nucleosome. These findings complement previous studies that showed(1) HMGB1 stimulates in vivo transcriptional activation at estrogen response elements and(2) knock down of HMGB1 expression by siR NA precipitously reduced transcriptional activation. The findings indicate that a major facet of the mechanism of HMGB1 action involves a restructuring of aspects of the nucleosome that appear to relax structural constraints within the nucleosome. The findings are extended to reveal the differences between ER and the other steroid hormone receptors. A working proposal outlines mechanisms that highlight the multiple facets that HMGB1 may utilize in restructuring the nucleosome.展开更多
AIM:To evaluate the inhibitory effects of Scolopendra subspinipes mutilans(SSM) on cerulein-induced acute pancreatitis(AP) in a mouse model.METHODS:SSM water extract(0.1,0.5,or 1 g/kg) was administrated intraperitonea...AIM:To evaluate the inhibitory effects of Scolopendra subspinipes mutilans(SSM) on cerulein-induced acute pancreatitis(AP) in a mouse model.METHODS:SSM water extract(0.1,0.5,or 1 g/kg) was administrated intraperitoneally 1 h prior to the first injection of cerulein.Once AP developed,the stable cholecystokinin analogue,cerulein was injected hourly,over a 6 h period.Blood samples were taken 6 h later to determine serum amylase,lipase,and cytokine levels.The pancreas and lungs were rapidly removed for morphological examination,myeloperoxidase assay,and real-time reverse transcription polymerase chain reaction.To specify the role of SSM in pancreatitis,the pancreatic acinar cells were isolated using collagenase method.Then the cells were pre-treated with SSM,then stimulated with cerulein.The cell viability,cytokine productions and high-mobility group box protein-1(HMGB-1) were measured.Furthermore,the regulating mechanisms of SSM action were evaluated.RESULTS:The administration of SSM significantly attenuated the severity of pancreatitis and pancreatitis associated lung injury,as was shown by the reduction in pancreatic edema,neutrophil infiltration,vacuolization and necrosis.SSM treatment also reduced pancreatic weight/body weight ratio,serum amylase,lipase and cytokine levels,and mRNA expression of multiple inflammatory mediators such as tumor necrosis factor-α and interleukin-1β.In addition,treatment with SSM inhibited HMGB-1 expression in the pancreas during AP.In accordance with in vivo data,SSM inhibited the cerulein-induced acinar cell death,cytokine,and HMGB-1 release.SSM also inhibited the activation of c-Jun NH2-terminal kinase,p38 and nuclear factor(NF)-κB.CONCLUSION:These results suggest that SSM plays a protective role during the development of AP and pancreatitis associated lung injury via deactivating c-Jun NH2-terminal kinase,p38 and NF-κB.展开更多
BACKGROUND High mobility group box-1 (HMGB1), recognized as a representative of damageassociated molecular patterns, is released during cell injury/death, triggering the inflammatory response and ultimately resulting ...BACKGROUND High mobility group box-1 (HMGB1), recognized as a representative of damageassociated molecular patterns, is released during cell injury/death, triggering the inflammatory response and ultimately resulting in tissue damage. Dozens of studies have shown that HMGB1 is involved in certain diseases, but the details on how injured hepatocytes release HMGB1 need to be elicited. AIM To reveal HMGB1 release mechanism in hepatocytes undergoing oxidative stress. METHODS C57BL6/J male mice were fed a high-fat diet for 12 wk plus a single binge of ethanol to induce severe steatohepatitis. Hepatocytes treated with H2O2 were used to establish an in vitro model. Serum alanine aminotransferase, liver H2O2 content and catalase activity, lactate dehydrogenase and 8-hydroxy-2- deoxyguanosine content, nicotinamide adenine dinucleotide (NAD+) levels, and Sirtuin 1 (Sirt1) activity were detected by spectrophotometry. HMGB1 release was measured by enzyme linked immunosorbent assay. HMGB1 translocation was observed by immunohistochemistry/immunofluorescence or Western blot. Relative mRNA levels were assayed by qPCR and protein expression was detected by Western blot. Acetylated HMGB1 and poly(ADP-ribose)polymerase 1 (Parp1) were analyzed by Immunoprecipitation. RESULTS When hepatocytes were damaged, HMGB1 translocated from the nucleus to the cytoplasm because of its hyperacetylation and was passively released outside both in vivo and in vitro. After treatment with Sirt1-siRNA or Sirt1 inhibitor (EX527), the hyperacetylated HMGB1 in hepatocytes increased, and Sirt1 activity inhibited by H2O2 could be reversed by Parp1 inhibitor (DIQ). Parp1 and Sirt1 are two NAD+-dependent enzymes which play major roles in the decision of a cell to live or die in the context of stress . We showed that NAD+ depletion attributed to Parp1 activation after DNA damage was caused by oxidative stress in hepatocytes and resulted in Sirt1 activity inhibition. On the contrary, Sirt1 suppressed Parp1 by negatively regulating its gene expression and deacetylation. CONCLUSION The functional inhibition between Parp1 and Sirt1 leads to HMGB1 hyperacetylation, which leads to its translocation from the nucleus to the cytoplasm and finally outside the cell.展开更多
文摘Eukaryotic chromatin consisting of nucleosomes connected by linker DNA is organized into higher order structures,which is facilitated by linker histone H1.Formation of chromatin compacts and protects the genome,but also hinders DNA transactions.Cells have evolved mechanisms to modify/remodel chromatin resulting in chromatin states suitable for genome functions.The high mobility group box(HMGB)proteins are non-histone chromatin architectural factors characterized by one or more HMGB motifs that bind DNA in a sequence nonspecific fashion.They play a major role in chromatin dynamics.The Saccharomyces cerevisiae(yeast hereafter)HMGB protein Hmo1 contains two HMGB motifs.However,unlike a canonical HMGB protein that has an acidic C-terminus,Hmo1 ends with a lysine rich,basic,C-terminus,resembling linker histone H1.Hmo1 exhibits characteristics of both HMGB proteins and linker histones in its multiple functions.For instance,Hmo1 promotes transcription by RNA polymerases I and II like canonical HMGB proteins but makes chromatin more compact/stable like linker histones.Recent studies have demonstrated that Hmo1 destabilizes/disrupts nucleosome similarly as other HMGB proteins in vitro and acts to maintain a common topological architecture of genes in yeast genome.This minireview reviews the functions of Hmo1 and the underlying mechanisms,highlighting recent discoveries.
基金supported by the National Natural Science Foundation of ChinaNos.81971047 (to WTL) and 82073910 (to XFW)+2 种基金the Natural Science Foundation of Jiangsu Province,No.BK20191253 (to XFW)Key R&D Program (Social Development) Project of Jiangsu Province,No.BE2019 732 (to WTL)Jiangsu Province Hospital (the First Affiliated Hospital of Nanjing Medical University) Clinical Capacity Enhancement Project,No.JSPH-511B2018-8 (to YBP)。
文摘Opioids,such as morphine,are the most potent drugs used to treat pain.Long-term use results in high tolerance to morphine.High mobility group box-1(HMGB1) has been shown to participate in neuropathic or inflammatory pain,but its role in morphine tolerance is unclear.In this study,we established rat and mouse models of morphine tolerance by intrathecal injection of morphine for 7 consecutive days.We found that morphine induced rat spinal cord neurons to release a large amount of HMGB1.HMGB1 regulated nuclear factor κB p65 phosphorylation and interleukin-1β production by increasing Toll-like receptor 4receptor expression in microglia,thereby inducing morphine tolerance.Glycyrrhizin,an HMGB1 inhibito r,markedly attenuated chronic morphine tole rance in the mouse model.Finally,compound C(adenosine 5’-monophosphate-activated protein kinase inhibitor) and zinc protoporphyrin(heme oxygenase-1 inhibitor)alleviated the morphine-induced release of HMGB1 and reduced nuclear factor κB p65 phosphorylation and interleukin-1β production in a mouse model of morphine tolerance and an SH-SY5Y cell model of morphine tole rance,and alleviated morphine tolerance in the mouse model.These findings suggest that morphine induces HMGB1 release via the adenosine 5’-monophosphate-activated protein kinase/heme oxygenase-1 signaling pathway,and that inhibiting this signaling pathway can effectively reduce morphine tole rance.
基金supported by a grant from the National Natural Science Foundation of China (No. 81071342)
文摘BACKGROUND: Liver failure in chronic hepatitis B (CHB) patients is a severe, life-threatening condition. Intestinal endotoxemia plays a significant role in the progress to liver failure. High mobility group box-1 (HMGB1) protein is involved in the process of endotoxemia. Regulatory T (Treg) cells maintain immune tolerance and contribute to the immunological hyporesponsiveness against HBV infection. However, the roles of HMGB1 and Treg cells in the pathogenesis of liver failure in CHB patients, and whether HMGB1 affects the immune activity of Treg cells are poorly known at present, and so were explored in this study. METHODS: The levels of HMGB1 expression were detected by ELISA, real-time RT-PCR, and Western blotting, and the percentage of CD4(+)CD25(+)CD127(low) Treg cells among CD4(+) cells was detected by flow cytometry in liver failure patients with chronic HBV infection, CHB patients, and healthy controls. Then, CD4(+)CD25(+)CD127(low) Treg cells isolated from the peripheral blood mononuclear cells from CHB patients were stimulated with HMGB1 at different concentrations or at various intervals. The effect of HMGB1 on the immune activity of Treg cells was assessed by a suppression assay of the allogeneic mixed lymphocyte response. The levels of forkhead box P3 (Foxp3) expression in Treg cells treated with HMGB1 were detected by RT-PCR and Western blotting. RESULTS: A higher level of HMGB1 expression and a lower percentage of Treg cells within the population of CIA(+) cells were found in liver failure patients than in CHB patients (82.6+/-20.1 mu g/L vs. 34.2+/-13.7 mu g/L; 4.55+/-1.34% vs. 9.52+/-3.89%, respectively). The immune activity of Treg cells was significantly weakened and the levels of Foxp3 expression were reduced in a dose- or time-dependent manner when Treg cells were stimulated with HMGB1 in vitro. CONCLUSIONS: The high level of HMGB1 and the low percentage of Treg cells play an important role in the pathogenesis of liver failure in patients with chronic HBV infection. Moreover, HMGB1 can weaken the immune activity of Treg cells. It is suggested that effectively inhibiting HMGB1 expression could be a feasible way to treat liver failure by suppressing endotoxemia and enhancing Treg cell activity.
基金This study was supported by the National Natural Science Foundation of China(No.30672178)National Basic Research Program of China(No.2005CB522602)the National Natural Science Outstanding Youth Foundation of China(No.30125020).
文摘Objective This study was performed to investigate the effect of high mobility group box-1 protein(HMGB1)on immune function of human T lymphocytes in vitro and explore its potential role in cell-mediated immune dysfunction.Methods Fresh blood was obtained from healthy adult volunteers and peripheral blood mononuclear cells(PBMCs)were isolated,then rhHMGB1 was added to PBMCs.Four-color flow cytometric(FCM)analysis was used for the measurement of intracellular cytokine including interleukin IL-4 and interferon IFN-?ELISA kits were employed for the determination of IL-2 and sIL-2R protein levels in cell culture supernatants.Results(1)Different stimulating time and dosage of rhHMGB1 did not alter the number of IFN-αpositive cells(Th1).rhHMGB1 stimulation provoked a dose-dependent and time-dependent increase in Th2 subset and decrease in ratio of Th1 to Th2.(2)Compared with the untreated cells,when the cells were coincubated with rhHMGB1(10-100ng/ml)for 12 hrs,protein release of IL-2 and sIL-2R were significantly up-regulated.At 48 hrs,in contrast,protein production was relatively lower in cells after exposure to 100-1000 ng/ml rhHMGB1.Conclusions These findings demonstrated that HMGB1 has a dual influence on immune functions of human T lymphocytes.
文摘Sepsis is an infection induced systemic inflammatory response syndrome and is a major cause of morbidity as well as mortality in intensive care units. A growing body of evidence suggests that the activation of a proinflammatory cascade is responsible for the development of immune dysfunction, susceptibility to severe sepsis and septic shock. The present theories of sepsis as a dysregulated inflammatory response and immune function, as manifested by excessive release of inflammatory mediators such as high mobility group box 1 protein （HMGB1）, are supported by increasing studies employing animal models and clinical observations of sepsis. HMGB1, originally described as a DNA-binding protein and released passively by necrotic cells and actively by macrophages/monocytes, has been discovered to be one of essential cytokines that mediates the response to infection, injury and inflammation. A growing number of studies still focus on the inflammation-regulatory function and its contribution to infectious and inflammatory disorders, recent data suggest that HMGB1 formation can also markedly influence the host cell-mediated immunity, including T lymphocytes and macrophages. Here we review emerging evidence that support extracellular HMGB1 as a late mediator of septic complications, and discuss the therapeutic potential of several HMGBl-targeting agents in experimental sepsis. In addition, with the development of traditional Chinese medicine in recent years, it has been proven that traditional Chinese herbal materials and their extracts have remarkable effective in treating severe sepsis. In this review, we therefore provide some new concepts of HMGBl-targeted Chinese herbal therapies in sepsis.
基金supported,in part,by grants from the National Natural Science Foundation(81130035,30971192,81071545,81272090,81121004)the National Basic Research Program of China(2012CB518102)
文摘High mobility group box-1 protein(HMGB1),which is a nuclear protein,participates in chromatin architecture and transcriptional regulation.When released from cells,HMGB1 also plays a well-established role as a pro-inflammatory mediator during innate immune responses to injury.In the initial stage of injury,there is a release of large quantities of early pro-inflammatory mediators to initiate or perpetuate immune responses against pathogens,but this pro-inflammatory period is transient,and it is followed by a prolonged period of immune suppression.At present,several lines of evidences have suggested that HMGB1 is a late cytokine provoking delayed endotoxin morbidity,which may enhance the production of early proinflammatory mediators,and it can contribute potently to the activation of different immune cells and play a role in the development of host cell-mediated immunity.The biology of HMGB1 has been extensively studied as a pro-inflammatory cytokine of systemic inflammation,however,this review will attempt to provide a summary of the effects of HMGB1 on different immune cells and its regulatory mechanism in acute insults.
基金Supported by National Science Foundation of China,No.81170438grant from Jiangsu Provincial Special Program of Medical Science,No.BL2012006
文摘The high mobility group box 1(HMGB1),which belongs to the subfamily of HMG-1/-2,is a highly conserved single peptide chain consisting of 215 amino acid residues with a molecular weight of approximately 24894 Da.HMGB1 is a ubiquitous nuclear protein in mammals and plays a vital role in inflammatory diseases.Acute pancreatitis is one of the most common causes of acute abdominal pain with a poor prognosis.Acute pancreatitis is an acute inflammatory process of the pancreas(duration of less than six months),for which the severe form is called severe acute pancreatitis(SAP).More and more studies have shown that HMGB1 has a bidirectional effect in the pathogenesis of SAP.Extracellular HMGB1 can aggravate the pancreatic inflammatory process,whereas intracellular HMGB1 has a protective effect against pancreatitis.The mechanism of HMGB1 is multiple,mainly through the nuclear factor-κB pathway.Receptors for advanced glycation endproducts and toll-like receptors(TLR),especially TLR-2 and TLR-4,are two major types of receptors mediating the inflammatory process triggered by HMGB1 and may be also the main mediators in the pathogenesis of SAP.HMGB1 inhibitors,such as ethyl pyruvate,pyrrolidine dithiocarbamate and Scolopendra subspinipes mutilans,can decrease the level of extracellular HMGB1 and are the promising targets in the treatment of SAP.
基金supported,in part,by grants from the National Natural Science Foundation(Nos.81130035,30901561,30971192,81071545)the National Basic Research Program of China(No.2012CB518102)the China Postdoctoral Science Foundation(Nos.20100480347,201104125)
文摘High mobility group box 1 protein （HMGB1） is a highly conserved, ubiquitous protein in the nuclei and cytoplasm of nearly all cell types. HMGB1 is secreted into the extracellular milieu and acts as a proinflammatory cytokine. In this article we reviewed briefly the cellular immune response mediated by HMGB1 in inflammation and sepsis. This systemic review is mainly based on our own work and other related reports HMGB1 can actively affect the immune functions of many types of cells including T lymphocytes, regulatory T cells （Tregs）, dendritic cells （DCs）, macrophages, and natural killer cells （NK cells）. Various cellular responses can be mediated by HMGB1 which binds to cell-surface receptors [e.g., the receptor for advanced glycation end products （RAGE）, Toll-like receptor （TLR）2, and TLR4]. Anti-HMGB1 treatment, such as anti-HMGB1 polyclonal or monoclonal antibodies, inhibitors （e.g., ethyl pyruvate） and antagonists （e.g., A box）, can protect against sepsis lethality and give a wider window for the treatment opportunity. HMGB1 is an attractive target for the development of new therapeutic strategies in the treatment of patients with septic complications.
文摘BACKGROUND： Vibrio vulnifi cus inside the body could activate the NF-!B signaling pathwayand initiate the inflammatory cascade. The lung is one of the earliest organs affected by sepsisassociated with acute lung injury. High mobility group protein B1 （HMGB1） is an important late-actingpro-infl ammatory cytokine involving in the pathophysiology of sepsis. It is also involved in the injuryprocess in the lung, liver and intestine. There has been no report on the involvement of HMGB1 inVibrio vulnifi cus sepsis-induced lung injury.METHODS： Sixty rats were randomly divided into a normal control group （group A, n=10） anda Vibrio vulnificus sepsis group （group B, n=50）. Sepsis was induced in the rats by subcutaneousinjection of Vibrio vulnificus （concentration 6×108 cfu/mL, volume 0.1 mL/100g）） into the left lowerlimbs. The rats in group B were sacrifi ced 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 wasobserved under a light microscope. The expressions of the HMGB1 gene and protein in the lungswere 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 wasconsidered statistically signifi cant.RESULTS： Compared to group A （0.652±0.177）, HMGB1 mRNA expression in the lungs ofgroup B was signifi cantly 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 wassignificantly 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 48hours （0.789±0.137, P=0.000） after infection （P〈0.05）. Compared to group A, pathological changesat 12 hours in group B indicate marked pulmonary vascular congestion, interstitial edema andinfl ammatory infi ltration. Alveolar cavity collapse and boundaries of the alveolar septum could not beclearly identifi ed.CONCLUSION： Vibrio vulnifi cus sepsis can lead to injury in rat lungs, and increased HMGB1expression in lung tissue may be one of the mechanisms for injury from Vibrio vulnifi cus sepsis.
文摘High mobility group protein 1(HMGB1) is a multifunctional protein that interacts with DNA and chromatin to influence the regulation of transcription, DNA replication and repair and recombination. We show that HMGB1 alters the structure and stability of the canonical nucleosome(N) in a nonenzymatic,adenosine triphosphate-independent manner. As a result, the canonical nucleosome is converted to two stable, physically distinct nucleosome conformers. Although estrogen receptor(ER) does not bind to its consensus estrogen response element within a nucleosome, HMGB1 restructures the nucleosome to facilitate strong ER binding. The isolated HMGB1-restructured nucleosomes(N' and N'') remain stable and exhibit a number of characteristics that are distinctly different from the canonical nucleosome. These findings complement previous studies that showed(1) HMGB1 stimulates in vivo transcriptional activation at estrogen response elements and(2) knock down of HMGB1 expression by siR NA precipitously reduced transcriptional activation. The findings indicate that a major facet of the mechanism of HMGB1 action involves a restructuring of aspects of the nucleosome that appear to relax structural constraints within the nucleosome. The findings are extended to reveal the differences between ER and the other steroid hormone receptors. A working proposal outlines mechanisms that highlight the multiple facets that HMGB1 may utilize in restructuring the nucleosome.
基金Supported by National Research Foundation of Korea grant funded by the Korea government MEST,No. 2010-0029498
文摘AIM:To evaluate the inhibitory effects of Scolopendra subspinipes mutilans(SSM) on cerulein-induced acute pancreatitis(AP) in a mouse model.METHODS:SSM water extract(0.1,0.5,or 1 g/kg) was administrated intraperitoneally 1 h prior to the first injection of cerulein.Once AP developed,the stable cholecystokinin analogue,cerulein was injected hourly,over a 6 h period.Blood samples were taken 6 h later to determine serum amylase,lipase,and cytokine levels.The pancreas and lungs were rapidly removed for morphological examination,myeloperoxidase assay,and real-time reverse transcription polymerase chain reaction.To specify the role of SSM in pancreatitis,the pancreatic acinar cells were isolated using collagenase method.Then the cells were pre-treated with SSM,then stimulated with cerulein.The cell viability,cytokine productions and high-mobility group box protein-1(HMGB-1) were measured.Furthermore,the regulating mechanisms of SSM action were evaluated.RESULTS:The administration of SSM significantly attenuated the severity of pancreatitis and pancreatitis associated lung injury,as was shown by the reduction in pancreatic edema,neutrophil infiltration,vacuolization and necrosis.SSM treatment also reduced pancreatic weight/body weight ratio,serum amylase,lipase and cytokine levels,and mRNA expression of multiple inflammatory mediators such as tumor necrosis factor-α and interleukin-1β.In addition,treatment with SSM inhibited HMGB-1 expression in the pancreas during AP.In accordance with in vivo data,SSM inhibited the cerulein-induced acinar cell death,cytokine,and HMGB-1 release.SSM also inhibited the activation of c-Jun NH2-terminal kinase,p38 and nuclear factor(NF)-κB.CONCLUSION:These results suggest that SSM plays a protective role during the development of AP and pancreatitis associated lung injury via deactivating c-Jun NH2-terminal kinase,p38 and NF-κB.
基金Supported by the National Natural Science Foundation of China,No.81503367 and No.81703832
文摘BACKGROUND High mobility group box-1 (HMGB1), recognized as a representative of damageassociated molecular patterns, is released during cell injury/death, triggering the inflammatory response and ultimately resulting in tissue damage. Dozens of studies have shown that HMGB1 is involved in certain diseases, but the details on how injured hepatocytes release HMGB1 need to be elicited. AIM To reveal HMGB1 release mechanism in hepatocytes undergoing oxidative stress. METHODS C57BL6/J male mice were fed a high-fat diet for 12 wk plus a single binge of ethanol to induce severe steatohepatitis. Hepatocytes treated with H2O2 were used to establish an in vitro model. Serum alanine aminotransferase, liver H2O2 content and catalase activity, lactate dehydrogenase and 8-hydroxy-2- deoxyguanosine content, nicotinamide adenine dinucleotide (NAD+) levels, and Sirtuin 1 (Sirt1) activity were detected by spectrophotometry. HMGB1 release was measured by enzyme linked immunosorbent assay. HMGB1 translocation was observed by immunohistochemistry/immunofluorescence or Western blot. Relative mRNA levels were assayed by qPCR and protein expression was detected by Western blot. Acetylated HMGB1 and poly(ADP-ribose)polymerase 1 (Parp1) were analyzed by Immunoprecipitation. RESULTS When hepatocytes were damaged, HMGB1 translocated from the nucleus to the cytoplasm because of its hyperacetylation and was passively released outside both in vivo and in vitro. After treatment with Sirt1-siRNA or Sirt1 inhibitor (EX527), the hyperacetylated HMGB1 in hepatocytes increased, and Sirt1 activity inhibited by H2O2 could be reversed by Parp1 inhibitor (DIQ). Parp1 and Sirt1 are two NAD+-dependent enzymes which play major roles in the decision of a cell to live or die in the context of stress . We showed that NAD+ depletion attributed to Parp1 activation after DNA damage was caused by oxidative stress in hepatocytes and resulted in Sirt1 activity inhibition. On the contrary, Sirt1 suppressed Parp1 by negatively regulating its gene expression and deacetylation. CONCLUSION The functional inhibition between Parp1 and Sirt1 leads to HMGB1 hyperacetylation, which leads to its translocation from the nucleus to the cytoplasm and finally outside the cell.
