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Ikuro Maruyama - One of the best experts on this subject based on the ideXlab platform.
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plasma concentrations and importance of high mobility group box protein in the prognosis of organ failure in patients with disseminated intravascular coagulation
Thrombosis and Haemostasis, 2005Co-Authors: Tsuyoshi Hatada, Shingo Yamada, Hideo Wada, Tsutomu Nobori, Kazuhiro Okabayashi, Kazuo Maruyama, Yasunori Abe, Shinji Uemoto, Ikuro MaruyamaAbstract:High Mobility Group Box chromosomal protein 1 (HMGB1) is a nuclear DNA-binding protein acting as a proinflammatory cytokine when released in the extracellular space from necrotic cells, activated macrophages and dendritic cells. HMGB1 acts on a specific receptor, RAGE (receptor for advanced glycation endproducts), and induces prolonged inflammation, organ failure, septicaemia and death.The aim of the study was to determine the diagnostic value of plasma HMGB1 concentration and its role in the development of organ failure in patients with disseminated intravascular coagulation (DIC). Plasma HMGB-1 levels were measured in patients with suspected DIC and their relationships with DIC, organ failure and clinical outcome were determined. The study took place at the intensive care facility, Mie University School of Medicine and comprised 201 patients with suspected DIC.Plasma HMGB1 was below the detection limit in normal subjects, but moderately elevated in patients with infectious diseases (4.54 ± 8.18 ng/ml, mean±SD), malignancies (2.15 ± 5.34 ng/ml), and traumas (6.47 ± 13.13 ng/ml). DIC was associated with significantly high plasma HMGB1 (14.05 ± 12.56 ng/ml) in these patients.The highest HMGBI levels were in patients with organ failure (8.29 ± 10.99 ng/ml) and non-survivors (16.58 ± 11.01 ng/ml). HMGB1 plasma levels correlated with the DIC score and sepsis-related organ failure assessment (SOFA) score. In conclusion,our data suggest that HMGB-1 is a potentially suitable prognostic marker of OF or DIC.
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high mobility group box 1 HMGB1 quantified by elisa that dose not cross react with hmgb2
Critical Care, 2005Co-Authors: K Yakabe, Susan S Yamada, M Kobayashi, Ikuro MaruyamaAbstract:Recently, high mobility group box 1 (HMGB1) was identified as a late mediator of endotoxin lethality. Patients with sepsis who succumbed to infection had increased serum HMGB1. However, it revealed that HMGB1 and HMGB2, with extremely high homology (81%) to HMGB1, coexist in the serum. We report an ELISA method we have developed that measured only HMGB1 without simultaneous determination of HMGB2.
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contributions of high mobility group box protein in experimental and clinical acute lung injury
American Journal of Respiratory and Critical Care Medicine, 2004Co-Authors: Hiroshi Ueno, Ikuro Maruyama, Tomoyuki Matsuda, Satoru Hashimoto, Fumimasa Amaya, Yoshihiro Kitamura, Masaki Tanaka, Atsuko Kobayashi, Shingo Yamada, Naoki HasegawaAbstract:This study was performed to examine the putative role of high mobility group box (HMGB) protein in the pathogenesis of acute lung injury (ALI). Observations were made (1) in 21 patients who were septic with ALI and 15 patients with normal lung function and (2) in a mouse model 24 hours after intratracheal instillation of lipopolysaccharide (LPS). The concentrations of HMGB1 were increased in plasma and lung epithelial lining fluid of patients with ALI and mice instilled with LPS. LPS-induced ALI was mitigated by anti-HMGB1 antibody. Although this protein was not detected in the plasma of control humans or mice, the concentrations of HMGB1 in lung epithelial lining fluid or in bronchoalveolar lavage fluid were unexpectedly high. The nuclear expression of HMGB1 was apparent in epithelial cells surrounding terminal bronchioles in normal mice, whereas its nuclear and cytoplasmic expression was observed in alveolar macrophages in LPS-instilled mice. Lung instillation of HMGB2 did not cause as much inflammation as HMGB1. Extracellular HMGB1 may play a key role in the pathogenesis of clinical and experimental ALI. However, its expression in normal airways is noteworthy and suggests that it also plays a physiologic role in the lung.
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high mobility group protein 1 HMGB1 quantified by elisa with a monoclonal antibody that does not cross react with hmgb2
Clinical Chemistry, 2003Co-Authors: Shingo Yamada, K Yakabe, Keiichi Inoue, Hitoshi Imaizumi, Ikuro MaruyamaAbstract:High mobility group protein 1 (HMGB1) has been implicated in diverse cellular functions, including determination of nucleosomal structure and stability and binding of transcription factors to their cognate DNA sequences (1)(2)(3)(4). HMGB1 is also present in a membrane-associated form, termed amphoterin, that mediates neurite outgrowth (5). Amphoterin can interact with macrophage cell surface receptors for advanced glycation end products to enhance expression of tissue-type plasminogen activator (6). Recently, HMGB1 was identified as a late mediator of endotoxin lethality (7). Mice had increased serum HMGB1 concentrations after exposure to endotoxin, and sepsis patients who succumbed to infection also had increased serum HMGB1. It would therefore be useful to develop an easy and highly sensitive method to measure serum HMGB1. However, this study revealed that HMGB1 and HMGB2, with extremely high homology (81%) to HMGB1, coexist in the serum. We report an ELISA method we have developed that measures only HMGB1 without simultaneous determination of HMGB2. To prepare an anti-peptide monoclonal antibody reacting only with HMGB1, we selected a peptide sequence (peptide 1; GKGDPKKPRGK) with high antigenicity and different from that of HMGB2. The monoclonal anti-calf HMGB1 antibody was prepared against calf thymus-derived HMGB1, which was 98% homologous to human HMGB1. Each protein sample used for the analysis was prepared as follows. The peptides were purified and separated by HPLC. The peptide synthesized was added to maleimidobenzoyl- N -hydroxysuccinimide ester (Pierce Chemical Co.)-labeled keyhole limpet hemocyanin (Calbiochem) or maleimidobenzoyl- …
Marco Bianchi - One of the best experts on this subject based on the ideXlab platform.
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cancer cell secretion of the damp protein HMGB1 supports progression in malignant mesothelioma
Cancer Research, 2012Co-Authors: Sandro Jube, Marco Bianchi, Zeyana Rivera, Amy Powers, Ena Wang, Ian Pagano, Harvey I Pass, Giovanni Gaudino, Michele Carbone, Haining YangAbstract:Human malignant mesothelioma is an aggressive and highly lethal cancer that is believed to be caused by chronic exposure to asbestos and erionite. Prognosis for this cancer is generally poor because of late-stage diagnosis and resistance to current conventional therapies. The damage-associated molecular pattern protein HMGB1 has been implicated previously in transformation of mesothelial cells. Here we show that HMGB1 establishes an autocrine circuit in malignant mesothelioma cells that influences their proliferation and survival. Malignant mesothelioma cells strongly expressed HMGB1 and secreted it at high levels in vitro. Accordingly, HMGB1 levels in malignant mesothelioma patient sera were higher than that found in healthy individuals. The motility, survival, and anchorage-independent growth of HMGB1-secreting malignant mesothelioma cells was inhibited in vitro by treatment with monoclonal antibodies directed against HMGB1 or against the receptor for advanced glycation end products, a putative HMGB1 receptor. HMGB1 inhibition in vivo reduced the growth of malignant mesothelioma xenografts in severe-combined immunodeficient mice and extended host survival. Taken together, our findings indicate that malignant mesothelioma cells rely on HMGB1, and they offer a preclinical proof-of-principle that antibody-mediated ablation of HMBG1 is sufficient to elicit therapeutic activity, suggesting a novel therapeutic approach for malignant mesothelioma treatment. Cancer Res; 72(13); 3290–301. ©2012 AACR.
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aging related loss of the chromatin protein hmgb2 in articular cartilage is linked to reduced cellularity and osteoarthritis
Proceedings of the National Academy of Sciences of the United States of America, 2009Co-Authors: Noboru Taniguchi, Lorenza Ronfani, Marco Bianchi, B Carames, Setsuro Komiya, Ulrich Ulmer, Martin LotzAbstract:Osteoarthritis (OA) is the most common joint disease and typically begins with an aging-related disruption of the articular cartilage surface. Mechanisms leading to the aging-related cartilage surface degeneration remain to be determined. Here, we demonstrate that nonhistone chromatin protein high-mobility group box (HMGB) protein 2 is uniquely expressed in the superficial zone (SZ) of human articular cartilage. In human and murine cartilage, there is an aging-related loss of HMGB2 expression, ultimately leading to its complete absence. Mice genetically deficient in HMGB2 (Hmgb2−/−) show earlier onset of and more severe OA. This is associated with a profound reduction in cartilage cellularity attributable to increased cell death. These cellular changes precede glycosaminoglycan depletion and progressive cartilage erosions. Chondrocytes from Hmgb2−/− mice are more susceptible to apoptosis induction in vitro. In conclusion, HMGB2 is a transcriptional regulator specifically expressed in the SZ of human articular cartilage and supports chondrocyte survival. Aging is associated with a loss of HMGB2 expression and reduced cellularity, and this contributes to the development of OA.
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the long acidic tail of high mobility group box 1 HMGB1 protein forms an extended and flexible structure that interacts with specific residues within and between the hmg boxes
Biochemistry, 2004Co-Authors: S Knapp, Susanne Muller, Tiziana Bonaldi, Marco Bianchi, Giuseppe Digilio, Giovanna MuscoAbstract:HMGB1 (high mobility group B1) is a conserved chromosomal protein composed of two similar DNA binding domains (HMG box A and box B) linked by a short basic stretch to an acidic C-terminal tail of 30 residues. The acidic tail modulates the DNA binding properties of HMGB1, and its length differentiates the various HMGB family members. We synthesized a peptide that corresponds to the acidic tail in HMGB1 (T-peptide) and studied its binding to the single boxes and to the fragment corresponding to tailless HMGB1 (designated as ABbt fragment). CD spectroscopy showed that T-peptide stabilizes significantly the ABbt fragment and that the complex has an identical thermal stability as full-length HMGB1. Calorimetric and NMR data showed that T-peptide binds with a dissociation constant of 9 μM to box A and much more weakly to box B. 1H−15N HSQC spectra of full-length HMGB1 and of the ABbt fragment are very similar; the small chemical shift differences that exist correspond to those residues of the ABbt fragment that...
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a nuclear protein complex containing high mobility group proteins b1 and b2 heat shock cognate protein 70 erp60 and glyceraldehyde 3 phosphate dehydrogenase is involved in the cytotoxic response to dna modified by incorporation of anticancer nucleosi
Cancer Research, 2003Co-Authors: Eugene Y Krynetski, Marco Bianchi, Natalia F Krynetskaia, William E EvansAbstract:Thiopurine treatment of human leukemia cells deficient in components of the mismatch repair system (Nalm6) initiated apoptosis after incorporation into DNA, as revealed by caspase activation and terminal deoxynucleotidyl transferase-mediated nick end labeling assay. To elucidate the cellular sensor(s) responsible for recognition of DNA damage in cells with an inactive mismatch repair system, we isolated a multiprotein nuclear complex that preferentially binds DNA with thioguanine incorporated. The components of this nuclear multiprotein complex, as identified by protein mass spectroscopy, included high mobility group proteins 1 and 2 (HMGB1, HMGB2), heat shock protein HSC70, protein disulfide isomerase ERp60, and glyceraldehyde 3-phosphate dehydrogenase. The same complex was also shown to bind synthetic oligodeoxyribonucleotide duplexes containing the nonnatural nucleosides 1-beta-D-arabinofuranosylcytosine or 5-fluoro-2'-deoxyuridine. Fibroblast cell line derived from HMGB1(-/-) murine embryos had decreased sensitivity to thiopurines, with an IC(50) 10-fold greater than HMGB1-proficient cells (P < 0.0001) and exhibited comparable sensitivity to vincristine, a cytotoxic drug that is not incorporated into DNA. These findings indicate that the HMGB1-HMGB2-HSC70-ERp60-glyceraldehyde 3-phosphate dehydrogenase complex detects changes in DNA structure caused by incorporation of nonnatural nucleosides and is a determinant of cell sensitivity to such DNA modifying chemotherapy.
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the double life of HMGB1 chromatin protein architectural factor and extracellular signal
The EMBO Journal, 2001Co-Authors: Susanne Muller, Paola Scaffidi, Bernard Degryse, Tiziana Bonaldi, Lorenza Ronfani, Alessandra Agresti, Monica Beltrame, Marco BianchiAbstract:The High Mobility Group Box (HMGB) chromosomal proteins have been known and studied for a long time, but we have only recently started to understand their biological functions. They now have a clear reputation for being important architectural factors: they facilitate the assembly of site‐specific DNA binding proteins to their cognate binding sites within chromatin. Beyond this intranuclear function, they also have an extracellular function, which will be the prime focus of this short review. ### The HMGB family: structure, expression and nuclear function The HMGB family comprises the three proteins HMGB1 (previously HMG1), HMGB2 (previously HMG2) and HMGB3 (previously HMG4 or HMG2b) (Bustin, 2001). The structure of these three proteins is highly conserved (>80% amino acid identity), and their biochemical properties are so far indistinguishable. HMGBs are composed of three different domains. The two homologous DNA binding domains, HMG boxes A and B, are each ∼75 amino acids in length. The C‐terminal domain is highly negatively charged, consisting of a continuous stretch of glutamate or aspartate residues, and is longest in HMGB1 and shortest in HMGB3 (reviewed in Bustin, 1999; Bianchi and Beltrame, 2000). HMGB1 is ubiquitous and only 10 times less abundant than core histones, at ∼106 molecules per typical mammalian cell. Expression of the other two family members is more restricted: HMGB3 is only expressed to a significant amount during embryogenesis (Vaccari et al ., 1998); HMGB2 is widely expressed during embryonic development, but restricted mainly to lymphoid organs and testis in the adult mouse (Ronfani et al ., 2001). The localization of these proteins in most cells is nuclear. In their nuclear identity, HMGB1 and HMGB2 bind to the minor groove of DNA, causing a local distortion of the double helix. They have little or no sequence preference, and they are recruited to the site of action by specific DNA binding proteins. HMGB1 has …
Michal Stros - One of the best experts on this subject based on the ideXlab platform.
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nonhistone proteins HMGB1 and hmgb2 differentially modulate the response of human embryonic stem cells and the progenitor cells to the anticancer drug etoposide
Biomolecules, 2020Co-Authors: Alireza Jian Bagherpoor, Martin Kucirek, Radek Fedr, Soodabeh Abbasi Sani, Michal StrosAbstract:HMGB1 and HMGB2 proteins are abundantly expressed in human embryonic stem cells (hESCs) and hESC-derived progenitor cells (neuroectodermal cells, hNECs), though their functional roles in pluripotency and the mechanisms underlying their differentiation in response to the anticancer drug etoposide remain to be elucidated. Here, we show that HMGB1 and/or HMGB2 knockdown (KD) by shRNA in hESCs did not affect the cell stemness/pluripotency regardless of etoposide treatments, while in hESC-derived neuroectodermal cells, treatment resulted in differential effects on cell survival and the generation of rosette structures. The objective of this work was to determine whether HMGB1/2 proteins could modulate the sensitivity of hESCs and hESC-derived progenitor cells (hNECs) to etoposide. We observed that HMGB1 KD knockdown (KD) and, to a lesser extent, HMGB2 KD enhanced the sensitivity of hESCs to etoposide. Enhanced accumulation of 53BP1 on telomeres was detected by confocal microscopy in both untreated and etoposide-treated HMGB1 KD hESCs and hNECs, indicating that the loss of HMGB1 could destabilize telomeres. On the other hand, decreased accumulation of 53BP1 on telomeres in etoposide-treated HMGB2 KD hESCs (but not in HMGB2 KD hNECs) suggested that the loss of HMGB2 promoted the stability of telomeres. Etoposide treatment of hESCs resulted in a significant enhancement of telomerase activity, with the highest increase observed in the HMGB2 KD cells. Interestingly, no changes in telomerase activity were found in etoposide-treated control hNECs, but HMGB2 KD (unlike HMGB1 KD) markedly decreased telomerase activity in these cells. Changes in telomerase activity in the etoposide-treated HMGB2 KD hESCs or hNECs coincided with the appearance of DNA damage markers and could already be observed before the onset of apoptosis. Collectively, we have demonstrated that HMGB1 or HMGB2 differentially modulate the impact of etoposide treatment on human embryonic stem cells and their progenitor cells, suggesting possible strategies for the enhancement of the efficacy of this anticancer drug.
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hmgb2 is a negative regulator of telomerase activity in human embryonic stem and progenitor cells
The FASEB Journal, 2019Co-Authors: Martin Kucirek, Alireza Jian Bagherpoor, Josef Jaros, Ales Hampl, Michal StrosAbstract:High-mobility group box (HMGB)1 and HMGB2 proteins are the subject of intensive research because of their involvement in DNA replication, repair, transcription, differentiation, proliferation, cell...
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hmgb proteins interactions with dna and chromatin
Biochimica et Biophysica Acta, 2010Co-Authors: Michal StrosAbstract:HMGB proteins are members of the High Mobility Group (HMG) superfamily, possessing a unique DNA-binding domain, the HMG-box, which can bind non-B-type DNA structures (bent, kinked and unwound) with high affinity, and also distort DNA by bending/looping and unwinding. HMGBs (there are four HMGBs in mammals, HMGB1-4) are highly abundant and ubiquitously expressed non-histone proteins, acting as DNA chaperones influencing multiple processes in chromatin such as transcription, replication, recombination, DNA repair and genomic stability. Although HMGB1 is a nuclear protein, it can be secreted into the extracellular milieu as a signaling molecule when cells are under stress, in particular, when necrosis occurs. Mammalian HMGBs contain two HMG-boxes arranged in tandem, share more than 80% identity and differ in the length (HMGB1-3) or absence (HMGB4) of the acidic C-tails. The acidic tails consist of consecutive runs of only Glu/Asp residues of various length, and modulate the DNA-binding properties and functioning of HMGBs. HMGBs are subject to post-translational modifications which can fine-tune interactions of the proteins with DNA/chromatin and determine their relocation from the nucleus to the cytoplasm and secretion. Association of HMGBs with chromatin is highly dynamic, and the proteins affect the chromatin fiber as architectural factors by transient interactions with nucleosomes, displacement of histone H1, and facilitation of nucleosome remodeling and accessibility of the nucleosomal DNA to transcription factors or other sequence-specific proteins.
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HMGB1 and hmgb2 proteins up regulate cellular expression of human topoisomerase iiα
Nucleic Acids Research, 2009Co-Authors: Michal Stros, Eva Polanska, Soňa Struncova, Sarka PospisilovaAbstract:Topoisomerase IIα (topo IIα) is a nuclear enzyme involved in several critical processes, including chromosome replication, segregation and recombination. Previously we have shown that chromosomal protein HMGB1 interacts with topo IIα, and stimulates its catalytic activity. Here we show the effect of HMGB1 on the activity of the human topo IIα gene promoter in different cell lines. We demonstrate that HMGB1, but not a mutant of HMGB1 incapable of DNA bending, up-regulates the activity of the topo IIα promoter in human cells that lack functional retinoblastoma protein pRb. Transient over-expression of pRb in pRb-negative Saos-2 cells inhibits the ability of HMGB1 to activate the topo IIα promoter. The involvement of HMGB1 and its close relative, HMGB2, in modulation of activity of the topo IIα gene is further supported by knock-down of HMGB1/2, as evidenced by significantly decreased levels of topo IIα mRNA and protein. Our experiments suggest a mechanism of up-regulation of cellular expression of topo IIα by HMGB1/2 in pRb-negative cells by modulation of binding of transcription factor NF-Y to the topo IIα promoter, and the results are discussed in the framework of previously observed pRb-inactivation, and increased levels of HMGB1/2 and topo IIα in tumors.
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cloning the genes and dna binding properties of high mobility group b1 HMGB1 proteins from the human blood flukes schistosoma mansoni and schistosoma japonicum
Gene, 2006Co-Authors: Francisco Meirelles Bastos De Oliveira, Michal Stros, Isabel Caetano De Abreu Da Silva, Franklin David Rumjanek, Emmanuel Diasneto, Pedro Edson Moreira Guimaraes, Sergio Verjovskialmeida, Marcelo Rosado FantappieAbstract:The parasitic helminth Schistosoma mansoni contains three HMGB proteins, HMGB1, HMGB2 and HMGB3, of primary amino acid sequences highly similar to vertebrate proteins. In this report we describe the characterization of the HMGB1 proteins and their genes from S. mansoni and Schistosoma japonicum. The deduced amino acid sequences of HMGB1 proteins from both schistosome species are identical, and comprise 176 residues. The proteins contain the two evolutionarily highly conserved HMG-box domains, A and B, exhibiting 60% similarity to mammalian HMGB1. Unlike the human HMGB1 which contains an unbroken run of 30 glutamic or aspartic residues, the SmHMGB1 or SjHMGB1 proteins possess unusually short acidic C-terminal tails (5 acidic residues interrupted by 2 serines). Southern hybridization and DNA sequencing revealed a single copy HMGB1 gene, composed of 3 exons and two introns, in S. mansoni. The exon/intron boundaries are identical to those of the human HMGB1 gene, with the exception that the second exon of the SmHMGB1 gene which is not split into two exons as in the human HMGB1 gene. RNA blot analysis revealed that the SmHMGB1 gene is constitutively expressed in similar levels both in male and female worms. The single-sized mRNA for SmHMGB1 is consistent with the size derived from the cDNA. Although DNA binding properties of SmHMGB1 (or SjHMGB1) protein seem to be similar to those previously reported with human HMGB1, i.e., preferential binding to supercoiled DNA over linear DNA, specific recognition of DNA four-way junctions, DNA-induced supercoiling in the presence of topoisomerase I, and DNA bending, we have observed two important differences relative to those observed with the human HMGB1: (i) the inability of the isolated SmHMGB1 domain A to bend DNA (as revealed by T4 ligase-mediated circularization assay), and (ii) higher DNA supercoiling and bending potential of the SmHMGB1 protein as compared to its human counterpart. The latter finding may indicate that the long acidic C-tail of human HMGB1 has much stronger repressive role on DNA bending or DNA supercoiling by topoisomerase I at physiological ionic strength than the short C-tail of the SmHMGB1 protein. Considering the important role of HMGB1 in DNA replication, transcription, recombination, and in particularly, the mediation of inflammation responses in mammalian cells, further studies on schistosome HMGB proteins may provide valuable information related to schistosomiasis, where inflammation plays a critical role in this disease.
Shingo Yamada - One of the best experts on this subject based on the ideXlab platform.
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plasma concentrations and importance of high mobility group box protein in the prognosis of organ failure in patients with disseminated intravascular coagulation
Thrombosis and Haemostasis, 2005Co-Authors: Tsuyoshi Hatada, Shingo Yamada, Hideo Wada, Tsutomu Nobori, Kazuhiro Okabayashi, Kazuo Maruyama, Yasunori Abe, Shinji Uemoto, Ikuro MaruyamaAbstract:High Mobility Group Box chromosomal protein 1 (HMGB1) is a nuclear DNA-binding protein acting as a proinflammatory cytokine when released in the extracellular space from necrotic cells, activated macrophages and dendritic cells. HMGB1 acts on a specific receptor, RAGE (receptor for advanced glycation endproducts), and induces prolonged inflammation, organ failure, septicaemia and death.The aim of the study was to determine the diagnostic value of plasma HMGB1 concentration and its role in the development of organ failure in patients with disseminated intravascular coagulation (DIC). Plasma HMGB-1 levels were measured in patients with suspected DIC and their relationships with DIC, organ failure and clinical outcome were determined. The study took place at the intensive care facility, Mie University School of Medicine and comprised 201 patients with suspected DIC.Plasma HMGB1 was below the detection limit in normal subjects, but moderately elevated in patients with infectious diseases (4.54 ± 8.18 ng/ml, mean±SD), malignancies (2.15 ± 5.34 ng/ml), and traumas (6.47 ± 13.13 ng/ml). DIC was associated with significantly high plasma HMGB1 (14.05 ± 12.56 ng/ml) in these patients.The highest HMGBI levels were in patients with organ failure (8.29 ± 10.99 ng/ml) and non-survivors (16.58 ± 11.01 ng/ml). HMGB1 plasma levels correlated with the DIC score and sepsis-related organ failure assessment (SOFA) score. In conclusion,our data suggest that HMGB-1 is a potentially suitable prognostic marker of OF or DIC.
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contributions of high mobility group box protein in experimental and clinical acute lung injury
American Journal of Respiratory and Critical Care Medicine, 2004Co-Authors: Hiroshi Ueno, Ikuro Maruyama, Tomoyuki Matsuda, Satoru Hashimoto, Fumimasa Amaya, Yoshihiro Kitamura, Masaki Tanaka, Atsuko Kobayashi, Shingo Yamada, Naoki HasegawaAbstract:This study was performed to examine the putative role of high mobility group box (HMGB) protein in the pathogenesis of acute lung injury (ALI). Observations were made (1) in 21 patients who were septic with ALI and 15 patients with normal lung function and (2) in a mouse model 24 hours after intratracheal instillation of lipopolysaccharide (LPS). The concentrations of HMGB1 were increased in plasma and lung epithelial lining fluid of patients with ALI and mice instilled with LPS. LPS-induced ALI was mitigated by anti-HMGB1 antibody. Although this protein was not detected in the plasma of control humans or mice, the concentrations of HMGB1 in lung epithelial lining fluid or in bronchoalveolar lavage fluid were unexpectedly high. The nuclear expression of HMGB1 was apparent in epithelial cells surrounding terminal bronchioles in normal mice, whereas its nuclear and cytoplasmic expression was observed in alveolar macrophages in LPS-instilled mice. Lung instillation of HMGB2 did not cause as much inflammation as HMGB1. Extracellular HMGB1 may play a key role in the pathogenesis of clinical and experimental ALI. However, its expression in normal airways is noteworthy and suggests that it also plays a physiologic role in the lung.
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high mobility group protein 1 HMGB1 quantified by elisa with a monoclonal antibody that does not cross react with hmgb2
Clinical Chemistry, 2003Co-Authors: Shingo Yamada, K Yakabe, Keiichi Inoue, Hitoshi Imaizumi, Ikuro MaruyamaAbstract:High mobility group protein 1 (HMGB1) has been implicated in diverse cellular functions, including determination of nucleosomal structure and stability and binding of transcription factors to their cognate DNA sequences (1)(2)(3)(4). HMGB1 is also present in a membrane-associated form, termed amphoterin, that mediates neurite outgrowth (5). Amphoterin can interact with macrophage cell surface receptors for advanced glycation end products to enhance expression of tissue-type plasminogen activator (6). Recently, HMGB1 was identified as a late mediator of endotoxin lethality (7). Mice had increased serum HMGB1 concentrations after exposure to endotoxin, and sepsis patients who succumbed to infection also had increased serum HMGB1. It would therefore be useful to develop an easy and highly sensitive method to measure serum HMGB1. However, this study revealed that HMGB1 and HMGB2, with extremely high homology (81%) to HMGB1, coexist in the serum. We report an ELISA method we have developed that measures only HMGB1 without simultaneous determination of HMGB2. To prepare an anti-peptide monoclonal antibody reacting only with HMGB1, we selected a peptide sequence (peptide 1; GKGDPKKPRGK) with high antigenicity and different from that of HMGB2. The monoclonal anti-calf HMGB1 antibody was prepared against calf thymus-derived HMGB1, which was 98% homologous to human HMGB1. Each protein sample used for the analysis was prepared as follows. The peptides were purified and separated by HPLC. The peptide synthesized was added to maleimidobenzoyl- N -hydroxysuccinimide ester (Pierce Chemical Co.)-labeled keyhole limpet hemocyanin (Calbiochem) or maleimidobenzoyl- …
You Shang - One of the best experts on this subject based on the ideXlab platform.
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HMGB1 pi3k akt mtor signaling participates in the pathological process of acute lung injury by regulating the maturation and function of dendritic cells
Frontiers in Immunology, 2020Co-Authors: Xiaojing Zou, Haiyan Huang, Hongmei Zhang, Pei Liu, Shangwen Pan, Yaqi Ouyang, You ShangAbstract:Background: High-mobility group box 1 protein (HMGB1) was identified as a highly conserved DNA binding nuclear protein, which participates in the processes of acute lung injury (ALI). HMGB1 binds to its specific receptors not only to activate the nuclear factor (NF)-κB and mitogen-activated protein kinase (MAPK) pathways but also to regulate the activation of the phosphatidylinositol 3'-kinase/protein kinase B/mammalian target of the rapamycin (PI3K/AKT/mTOR) pathway. Mature dendritic cells (DCs) regulate acute lung inflammation and pathological injury in ALI. In addition, studies have shown that the activation of the PI3K/AKT/mTOR signaling pathway may regulate the function and maturation of DCs. Objective: Therefore, we speculate that HMGB1/PI3K/Akt/mTOR signaling participates in regulating the pathological process of ALI by regulating the maturation and function of DCs. Methods: Anti-HMGB1 antibody, rHMGB1, or LY294002 (PI3K inhibitor) was administered in a murine model of lipopolysaccharide (LPS)-induced ALI. For in vitro studies, generated bone marrow-derived dendritic cells (BMDCs) primed by LPS were stimulated with the same reagents. The effects of these different treatments were observed on the expression of PI3K, AKT, and mTOR and on the function of DCs. Results: HMGB1 upregulated the expression of PI3K, Akt, and mTOR mRNA and phosphorylated proteins in BMDCs. The HMGB1/PI3K/Akt/mTOR signaling pathway induced the maturation and antigen-presenting ability of lung DCs, mediated the percentage of myeloid DCs (mDCs), and enhanced the adhesion and chemotactic ability of lung DCs. Conclusions: HMGB1/PI3K/Akt/mTOR signaling participates in the pathological process of ALI by regulating the maturation and functions of DCs.
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High-mobility group box 1 protein participates in acute lung injury by activating protein kinase R and inducing M1 polarization.
Life Sciences, 2020Co-Authors: You Shang, Ting Zhou, Wei Xiong, Xiaojing ZouAbstract:High-mobility group box 1 protein (HMGB1) is a crucial proinflammatory cytokine that contributes to acute lung injury (ALI). Macrophages are known to express the primary receptors (Toll-like receptor [TLR] 2, and TLR4) of HMGB1 for transmitting intracellular signals. Studies have revealed that double-stranded RNA activated protein kinase R (PKR), which is expressed in macrophages, participates in ALI by regulating macrophage polarization and proinflammatory cytokine release, and that PKR is normally activated by a subset of TLRs. The present study investigated whether HMGB1 engages in ALI by activating PKR in macrophages and inducing classically activated macrophage (M1) polarization via TLR2- and TLR4-mediated nuclear factor (NF)-κB signaling pathways. In an vivo mouse model of lipopolysaccharide (LPS)-induced ALI, anti-HMGB1, rHMGB1, LPS-RS (TLR2 and TLR4 antagonist), or C16 (PKR inhibitor) was administered to mice 2 h after LPS challenge or 1 h before LPS challenge. In vitro, bone marrow-derived macrophages from mice primed with LPS were stimulated with or without anti-HMGB1, rHMGB1, LPS-RS, or C16. Our studies revealed that rHMGB1 stimulation induced M1 polarization in ALI, and that anti-HMGB1 and C16 treatments had the opposite effect. Anti-HMGB1 and LPS-RS significantly inhibited LPS-induced PKR expression in macrophages; however, rHMGB1 administration increased PKR expression. These results indicate that HMGB1 participates in the pathogenesis of ALI by activating PKR in macrophages and inducing M1 polarization through TLR2- and TLR4-mediated NF-κB signaling pathways.