Language：English   Publishing type：Research paper (scientific journal)   Publisher：FRONTIERS MEDIA SA  

BackgroundSystemic allergic reaction is characterized by vasodilation and vascular leakage, which causes a rapid, precipitous and sustained decrease in arterial blood pressure with a concomitant decrease of cardiac output. Histamine is a major mediator released by mast cells in allergic inflammation and response. It causes a cascade of inflammation and strongly increases vascular permeability within minutes through its four G-protein-coupled receptors (GPCRs) on endothelial cells. High mobility group box-1 (HMGB1), a nonhistone chromatin-binding nuclear protein, can be actively secreted into the extracellular space by endothelial cells. HMGB1 has been reported to exert pro-inflammatory effects on endothelial cells and to increase vascular endothelial permeability. However, the relationship between histamine and HMGB1-mediated signaling in vascular endothelial cells and the role of HMGB1 in anaphylactic-induced hypotension have never been studied. Methods and resultsEA.hy 926 cells were treated with different concentrations of histamine for the indicated periods. The results showed that histamine induced HMGB1 translocation and release from the endothelial cells in a concentration- and time-dependent manner. These effects of histamine were concentration-dependently inhibited by d-chlorpheniramine, a specific H-1 receptor antagonist, but not by H-2 or H-3/4 receptor antagonists. Moreover, an H-1-specific agonist, 2-pyridylethylamine, mimicked the effects of histamine, whereas an H-2-receptor agonist, 4-methylhistamine, did not. Adrenaline and noradrenaline, which are commonly used in the clinical treatment of anaphylactic shock, also inhibited the histamine-induced HMGB1 translocation in endothelial cells. We therefore established a rat model of allergic shock by i.v. injection of compound 48/80, a potent histamine-releasing agent. The plasma HMGB1 levels in compound 48/80-injected rats were higher than those in controls. Moreover, the treatment with anti-HMGB1 antibody successfully facilitated the recovery from compound 48/80-induced hypotension. ConclusionHistamine induces HMGB1 release from vascular endothelial cells solely through H-1 receptor stimulation. Anti-HMGB1 therapy may provide a novel treatment for life-threatening systemic anaphylaxis.

DOI： 10.3389/fimmu.2022.930683

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Intracerebral hemorrhage (ICH) is recognized as a severe clinical problem lacking effective treatment. High mobility group box-1 (HMGB1) exhibits inflammatory cytokine-like activity once released into the extracellular space from the nuclei. We previously demonstrated that intravenous injection of rat anti-HMGB1 monoclonal antibody (mAb) remarkably ameliorated brain injury in a rat ICH model. Therefore, we developed a humanized anti-HMGB1 mAb (OKY001) for clinical use. The present study examined whether and how the humanized anti-HMGB1 mAb ameliorates ICH injury in common marmosets. The results show that administration of humanized anti-HMGB1 mAb inhibited HMGB1 release from the brain into plasma, in association with a decrease of 4-hydroxynonenal (4-HNE) accumulation and a decrease in cerebral iron deposition. In addition, humanized anti-HMGB1 mAb treatment resulted in a reduction in brain injury volume at 12 d after ICH induction. Our in vitro experiment showed that recombinant HMGB1 inhibited hemoglobin uptake by macrophages through CD163 in the presence of haptoglobin, suggesting that the release of excess HMGB1 from the brain may induce a delay in hemoglobin scavenging, thereby allowing the toxic effects of hemoglobin, heme, and Fe2+ to persist. Finally, humanized anti-HMGB1 mAb reduced body weight loss and improved behavioral performance after ICH. Taken together, these results suggest that intravenous injection of humanized anti-HMGB1 mAb has potential as a novel therapeutic strategy for ICH.

DOI： 10.3390/cells11192970

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Clinical evidence indicates that cognitive impairment is a common comorbidity of chronic pain, including neuropathic pain, but the mechanism underlying cognitive impairment remains unclear. Neuroinflammation plays a critical role in the development of both neuropathic pain and cognitive impairment. High-mobility group box 1 (HMGB1) is a proinflammatory molecule and could be involved in neuroinflammation-mediated cognitive impairment in the neuropathic pain state. Hippocampal microglial activation in mice has been associated with cognitive impairment. Thus, the current study examined a potential role of HMGB1 and microglial activation in cognitive impairment in mice with neuropathic pain due to a partial sciatic nerve ligation (PSNL). Mice developed cognitive impairment over two weeks, but not one week, after nerve injury. Nerve-injured mice demonstrated decreased nuclear fraction HMGB1, suggesting increased extracellular release of HMGB1. Furthermore, two weeks after PSNL, significant microglia activation was observed in hippocampus. Inhibition of microglial activation with minocycline, local hippocampal microglia depletion with clodronate liposome, or blockade of HMGB1 with either glycyrrhizic acid (GZA) or anti-HMGB1 antibody in PSNL mice reduced hippocampal microglia activation and ameliorated cognitive impairment. Other changes in the hippocampus of PSNL mice potentially related to cognitive impairment, including decreased hippocampal neuron dendrite length and spine densities and decreased alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor (AMPAR) subunits, were prevented with anti-HMGB1 antibody treatment. The current findings suggest that neuro-inflammation involves a number of cellular-level changes and microglial activation. Blocking neuroinflammation, particularly through blocking HMGB1 could be a novel approach to reducing co-morbidities such as cognitive impairment associated with neuropathic pain.

DOI： 10.1016/j.expneurol.2022.114146

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Oxaliplatin often induces peripheral neuropathy, a dose-limiting adverse reaction, and in rare cases leads to sinusoidal obstruction syndrome. We thus conducted a retrospective cohort study to examine the relationship between oxaliplatin-induced peripheral neuropathy (OIPN) and hepatic impairment, and then perform a fundamental study to analyze the underlying mechanisms. Analysis of medical records in cancer patients treated with oxaliplatin indicated that laboratory test parameters of hepatic impairment including AST, ALT and APRI (AST to platelet ratio index) moderately increased during oxaliplatin treatment, which was positively correlated with the severity of OIPN (grades 1-4), and associated with later incidence of survivors with OIPN grades ≥2. In mice, hepatic injury induced by CCl4 or ethanol accelerated OIPN in mice, an effect prevented by inactivation of high mobility group box 1 (HMGB1), known to participate in OIPN, by the neutralizing antibody or thrombomodulin alfa capable of promoting its thrombin-dependent degradation. Oxaliplatin also aggravated the hepatic injury in mice. CCl4 released HMGB1 from cultured hepatic parenchymal cells, and oxaliplatin at clinically achievable concentrations released HMGB1 from hepatic parenchymal and non-parenchymal cells. Our clinical and preclinical data suggest that the development of mild hepatic impairment during oxaliplatin treatment is associated with later aggravation of OIPN.

DOI： 10.1016/j.jphs.2022.01.006

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Muscle cell death in polymyositis is induced by CD8(+) cytotoxic T lymphocytes. We hypothesized that the injured muscle fibers release pro-inflammatory molecules, which would further accelerate CD8(+) cytotoxic T lymphocytes-induced muscle injury, and inhibition of the cell death of muscle fibers could be a novel therapeutic strategy to suppress both muscle injury and inflammation in polymyositis. Here, we show that the pattern of cell death of muscle fibers in polymyositis is FAS ligand-dependent necroptosis, while that of satellite cells and myoblasts is perforin 1/granzyme B-dependent apoptosis, using human muscle biopsy specimens of polymyositis patients and models of polymyositis in vitro and in vivo. Inhibition of necroptosis suppresses not only CD8(+) cytotoxic T lymphocytes-induced cell death of myotubes but also the release of inflammatory molecules including HMGB1. Treatment with a necroptosis inhibitor or anti-HMGB1 antibodies ameliorates myositis-induced muscle weakness as well as muscle cell death and inflammation in the muscles. Thus, targeting necroptosis in muscle cells is a promising strategy for treating polymyositis providing an alternative to current therapies directed at leukocytes.

DOI： 10.1038/s41467-021-27875-4

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Parkinson's disease (PD) patients often complain of pain, but this problem has been neglected and is poorly understood. High mobility group box-1 (HMGB1), an alarmin/damage-associated molecular patterns protein, is increased in the cerebrospinal fluid in PD patients. However, little is known of the relationship between HMGB1 and pain associated with PD. Here, we investigated the role of central HMGB1 in the regulation of nociceptive hypersensitivity in a mouse model of PD. Male ddY mice were microinjected unilaterally with 6-hydroxydop-amine (6OHDA) into the striatum. These hemi-PD mice were treated with anti-HMGB1 neutralizing antibody (nAb; 10 mu g in 10 mu L) by intranasal (i.n.) administration. The mechanical hypersensitivity of the hind paws was evaluated with the von Frey test. Spinal microglial activity was analyzed by immunostaining for ionized calcium-binding adapter molecule 1. The 6OHDA-administered mice displayed unilateral loss of dopamine neurons in the substantia nigra and mechanical hypersensitivity in both hind paws. Moreover, spinal microglia were activated in these hemi-PD mice. Twenty-eight days after the 6OHDA injections, repeated i.n., but not systemic, treatment with anti-HMGB1 nAb inhibited the bilateral mechanical hypersensitivity and spinal microglial activation. However, the anti-HMGB1 nAb did not ameliorate the dopamine neuron loss. Moreover, intracerebroventricular injection with recombinant HMGB1 induced mechanical hypersensitivity. These findings indicate that HMGB1 is involved in the maintenance of nociceptive symptoms in hemi-PD mice via spinal microglial activation. Therefore, central HMGB1 may have potential as a therapeutic target for pain associated with PD.

DOI： 10.1016/j.biopha.2021.112479

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We examined the role of ATP and high mobility group box 1 (HMGB1) in paclitaxel-induced peripheral neuropathy (PIPN). PIPN in mice was prevented by HMGB1 neutralization, macrophage depletion, and P2X7 or P2X4 blockade. Paclitaxel and ATP synergistically released HMGB1 from macrophage-like RAW264.7 cells, but not neuron-like NG108-15 cells. The paclitaxel-induced HMGB1 release from RAW264.7 cells was accelerated by co-culture with NG108-15 cells in a manner dependent on P2X7 or P2X4. Paclitaxel released ATP from NG108-15 cells, but not RAW264.7 cells. Thus, PIPN is considered to involve acceleration of HMGB1 release from macrophages through P2X7 and P2X4 activation by neuron-derived ATP.

DOI： 10.1016/j.jphs.2021.11.003

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Language：Japanese   Publisher：Japanese Pharmacological Society  

Sepsis is one of the leading cause of death worldwide. Recently, several studies suggested that free-hemoglobin and heme derived from hemolysis are important factors which may be associated with severity of septic patients including COVID-19. In other words, hemolysis-derived products enhance the inflammatory responses as damage-associated molecular patterns (DAMPs) in both intravascular and extravascular space. In addition, hemoglobin has vasoconstrictive activity by depleting nitric oxide, whereas heme or Fe²⁺ produce reactive oxygen species (ROS) through Fenton reaction leading to tissue injury. At present, we have no therapeutic options against sepsis-related hemolysis in clinical settings, however, there are might be two therapeutic strategies in this regard. One is supplemental therapy of depleted scavenging proteins such as haptoglobin and hemopexin, the other is activation of the internal scavenging system including macrophage-CD163 pathway. These novel targets against sepsis are also critical for the next pandemic. We will show you our recent data aiming at anti-hemolytic therapy.

DOI： 10.1254/jpssuppl.95.0_1-s03-1

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Spinal cord injury (SCI) causes motor and sensory deficits and is currently considered an incurable disease. We have previously reported that administration of anti-High Mobility Group Box-1 monoclonal antibody (anti-HMGB1 mAb) preserved lesion area and improved locomotion recovery in mouse model of SCI. In order to further enhance the recovery, we here examined combinatorial treatment of anti-HMGB1 mAb and epothilone B (Epo B), which has been reported to promote axon regeneration. This combinatorial treatment significantly increased hindlimb movement compared with anti-HMGB1 mAb alone, although Epo B alone failed to increase functional recovery. These results are in agreement with that anti-HMGB1 mAb alone was able to decrease the lesion area spreading and increase the surviving neuron numbers around the lesion, whereas Epo B facilitated axon outgrowth only in combination with anti-HMGB1 mAb, suggesting that anti-HMGB1 mAb-dependent tissue preservation is necessary for Epo B to exhibit its therapeutic effect. Taken together, the combinatorial treatment can be considered as a novel and clinically applicable strategy for SCI.

DOI： 10.1016/j.neures.2021.04.002

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High mobility group box-1 (HMGB1) is a ubiquitous non-histone nuclear protein that plays a key role as a transcriptional activator, with its extracellular release provoking inflammation. Inflammatory responses are essential in methamphetamine (METH)-induced acute dopaminergic neurotoxicity. In the present study, we examined the effects of neutralizing anti-HMGB1 monoclonal antibody (mAb) on METH-induced dopaminergic neurotoxicity in mice. BALB/c mice received a single intravenous administration of anti-HMGB1 mAb prior to intraperitoneal injections of METH (4 mg/kg × 2, at 2-h intervals). METH injections induced hyperthermia, an increase in plasma HMGB1 concentration, degeneration of dopaminergic nerve terminals, accumulation of microglia, and extracellular release of neuronal HMGB1 in the striatum. These METH-induced changes were significantly inhibited by intravenous administration of anti-HMGB1 mAb. In contrast, blood-brain barrier disruption occurred by METH injections was not suppressed. Our findings demonstrated the neuroprotective effects of anti-HMGB1 mAb against METH-induced dopaminergic neurotoxicity, suggesting that HMGB1 could play an initially important role in METH toxicity.

DOI： 10.1007/s12640-021-00402-5

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Given the role of macrophage-derived high mobility group box 1 (HMGB1) in chemotherapy-induced peripheral neuropathy (CIPN) caused by paclitaxel, we analyzed the role of HMGB1 and macrophages in the CIPN caused by bortezomib, a proteasome-inhibiting chemotherapeutic agent used for the treatment of multiple myeloma. Repeated administration of bortezomib caused CIPN accompanied by early-stage macrophage accumulation in the dorsal root ganglion. This CIPN was prevented by an anti-HMGB1-neutralizing antibody, thrombomodulin alfa capable of accelerating thrombin-dependent degradation of HMGB1, antagonists of the receptor for advanced glycation end-products (RAGE) and C-X-C motif chemokine receptor 4 (CXCR4), known as HMGB1-targeted membrane receptors, or macrophage depletion with liposomal clodronate, as reported in a CIPN model caused by paclitaxel. In macrophage-like RAW264.7 cells, bortezomib as well as MG132, a well-known proteasome inhibitor, caused HMGB1 release, an effect inhibited by caspase inhibitors but not inhibitors of NF-κB and p38 MAP kinase, known to mediate paclitaxel-induced HMGB1 release from macrophages. Bortezomib increased cleaved products of caspase-8 and caused nuclear fragmentation or condensation in macrophages. Repeated treatment with the caspase inhibitor prevented CIPN caused by bortezomib in mice. Our findings suggest that bortezomib causes caspase-dependent release of HMGB1 from macrophages, leading to the development of CIPN via activation of RAGE and CXCR4.

DOI： 10.3390/cells10102550

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Persistent pain following orofacial surgery is not uncommon. High mobility group box 1 (HMGB1), an alarmin, is released by peripheral immune cells following nerve injury and could be related to pain associated with trigeminal nerve injury. Distal infraorbital nerve chronic constriction injury (dIoN-CCI) evokes pain-related behaviors including increased facial grooming and hyper-responsiveness to acetone (cutaneous cooling) after dIoN-CCI surgery in mice. In addition, dIoN-CCI mice developed conditioned place preference to mirogabalin, suggesting increased neuropathic pain-related aversion. Treatment of the infraorbital nerve with neutralizing antibody HMGB1 (anti-HMGB1 nAb) before dIoN-CCI prevented both facial grooming and hyper-responsiveness to cooling. Pretreatment with anti-HMGB1 nAb also blocked immune cell activation associated with trigeminal nerve injury including the accumulation of macrophage around the injured IoN and increased microglia activation in the ipsilateral spinal trigeminal nucleus caudalis. The current findings demonstrated that blocking of HMGB1 prior to nerve injury prevents the onset of pain-related behaviors, possibly through blocking the activation of immune cells associated with the nerve injury, both within the CNS and on peripheral nerves. The current findings further suggest that blocking HMGB1 before tissue injury could be a novel strategy to prevent the induction of chronic pain following orofacial surgeries.

DOI： 10.3390/molecules26072035

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

High mobility box 1 (HMGB1), a damage-associated molecular pattern, has crucial roles in induction of neuropathic pain. Upregulation of HMGB1 around the injured sciatic nerve contributes to mechanical hypersensitivity following partial sciatic nerve ligation (PSNL) of mice. However, central mechanisms mediating perineural HMGB1-induced nociceptive hypersensitivity, especially within the spinal dorsal horn, have not been determined. The current study shows that perineural treatment of naïve mice with recombinant HMGB1, which mimics increased HMGB1 around the injured sciatic nerve of PSNL mice, significantly induced activation of microglia, but not astrocytes, in the spinal dorsal horn. Intraperitoneal injection of minocycline, a microglial inhibitor, ameliorated perineural rHMGB1-induced mechanical hypersensitivity. In addition, blockade of spinal N-methyl-D-aspartate (NMDA) receptors significantly prevented perineural rHMGB1-induced mechanical hypersensitivity and microglial activation. In contrast, non-NMDA receptors, neurokinin 1 receptor, colony-stimulating factor 1 receptor and P2Y12 receptor were not involved in perineural rHMGB1-induced mechanical hypersensitivity. Furthermore, repeated perineural treatment with an anti-HMGB1 antibody blocked activation of spinal microglia in PSNL mice. Collectively, the current findings demonstrate that increased HMGB1 around injured sciatic nerve might induce nociceptive hypersensitivity through activation of spinal microglia. Thus, HMGB1-dependent mechanisms between the injured sciatic nerve and spinal dorsal horn could be crucial in induction of neuropathic pain.

DOI： 10.1016/j.bcp.2021.114496

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Histidine-rich glycoprotein (HRG) is a multifunctional plasma protein and maintains the homeostasis of blood cells and vascular endothelial cells. In the current study, we demonstrate that HRG and recombinant HRG concentration dependently induced the phagocytic activity of isolated human neutrophils against fluorescence-labeled Escherichia coli and Staphylococcus aureus through the stimulation of CLEC1A receptors, maintaining their spherical round shape. The phagocytosis-inducing effects of HRG were inhibited by a specific anti-HRG Ab and enhanced by opsonization of bacteria with diluted serum. HRG and C5a prolonged the survival time of isolated human neutrophils, in association with a reduction in the spontaneous production of extracellular ROS. In contrast, HRG maintained the responsiveness of neutrophils to TNF-α, zymosan, and E. coli with regard to reactive oxygen species production. The blocking Ab for CLEC1A and recombinant CLEC1A-Fc fusion protein significantly inhibited the HRG-induced neutrophil rounding, phagocytic activity, and prolongation of survival time, suggesting the involvement of the CLEC1A receptor in the action of HRG on human neutrophils. These results as a whole indicated that HRG facilitated the clearance of E. coli and S. aureus by maintaining the neutrophil morphology and phagocytosis, contributing to the antiseptic effects of HRG in vivo.

DOI： 10.4049/jimmunol.2000817

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Language：Japanese   Publisher：Japanese Pharmacological Society  

Introduction

Spinal cord ischemia and reperfusion (I/R) injury is one of the most devastating complications after thoracic and thoracoabdominal aortic aneurysm surgery. Several studies showed that levels of HMGB1 in serum were increased in patients who suffered from spinal cord I/R injury. These data strongly suggest that HMGB1 may play a crucial role in spinal cord I/R injury.

Materials and Methods

Male New Zealand white rabbits were used for the experiments. The abdominal aorta at the level of the left renal artery was exposed, and, after heparinization, occluded for 11 minutes. The rabbits were intravenously administered an anti-HMGB1 mAb (#10-22, 2mg/kg) or class-matched control IgG (anti-keyhole limpet hemocyanin mAb) twice immediately and 6h after reperfusion. The neurological findings were assessed at 6, 24 and 48 hours after reperfusion. At 48hr after reperfusion, the rabbits were sacrificed to obtain the specimen of spinal cord and blood samples.

Results

Administration of anti-HMGB1 mAb ameliorated the intensity of spinal cord infarction and preserved the number of motor neuron cells, in association with decreased activated microglia and astrocyte. Consequently, anti-HMGB1 mAb significantly improved the neurological outcomes after spinal I/R injury in rabbits.  These results strongly indicate that HMGB1 plays a critical role in the development of spinal cord I/R induced secondary injury through the amplification of inflammatory response.

Conclusion

Intravenous injection of neutralizing anti-HMGB1 mAb has potential as a novel therapeutic strategy for spinal cord I/R injury.

DOI： 10.1254/jpssuppl.94.0_3-y-f2-1

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Increasing evidence suggests that inflammatory responses are involved in the progression of brain injuries induced by a diverse range of insults, including ischemia, hemorrhage, trauma, epilepsy, and degenerative diseases. During the processes of inflammation, disruption of the blood-brain barrier (BBB) may play a critical role in the enhancement of inflammatory responses and may initiate brain damage because the BBB constitutes an interface between the brain parenchyma and the bloodstream containing blood cells and plasma. The BBB has a distinct structure compared with those in peripheral tissues: it is composed of vascular endothelial cells with tight junctions, numerous pericytes surrounding endothelial cells, astrocytic endfeet, and a basement membrane structure. Under physiological conditions, the BBB should function as an important element in the neurovascular unit (NVU). High mobility group box-1 (HMGB1), a nonhistone nuclear protein, is ubiquitously expressed in almost all kinds of cells. HMGB1 plays important roles in the maintenance of chromatin structure, the regulation of transcription activity, and DNA repair in nuclei. On the other hand, HMGB1 is considered to be a representative damage-associated molecular pattern (DAMP) because it is translocated and released extracellularly from different types of brain cells, including neurons and glia, contributing to the pathophysiology of many diseases in the central nervous system (CNS). The regulation of HMGB1 release or the neutralization of extracellular HMGB1 produces beneficial effects on brain injuries induced by ischemia, hemorrhage, trauma, epilepsy, and Alzheimer's amyloidpathy in animal models and is associated with improvement of the neurological symptoms. In the present review, we focus on the dynamics of HMGB1 translocation in different disease conditions in the CNS and discuss the functional roles of extracellular HMGB1 in BBB disruption and brain inflammation. There might be common as well as distinct inflammatory processes for each CNS disease. This review will provide novel insights toward an improved understanding of a common pathophysiological process of CNS diseases, namely, BBB disruption mediated by HMGB1. It is proposed that HMGB1 might be an excellent target for the treatment of CNS diseases with BBB disruption.

DOI： 10.3390/cells9122650

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER SOC PHARMACOLOGY EXPERIMENTAL THERAPEUTICS  

Histidine-rich glycoprotein (HRG) treatment ameliorated the survival rate of septic mice by suppressing excess immunothrombus formation. Although such findings suggested that HRG may be one of the most useful drugs for sepsis, obtaining a stable experimental system to standardize the HRG drug product is difficult to achieve using neutrophils isolated from volunteers. This is due to the short survival time and individual differences of human neutrophils. In the present study, we determined whether the differentiated neutrophil-like cell lines exhibited similar responses to HRG compared with human purified neutrophils. All-trans retinoic acid (ATRA) was employed to induce the differentiation of the human myeloid leukemia cell lines HL-60 and NB-4. Thereafter, the cells were treated with Hank's balanced salt solution, human serum albumin, or HRG. The effects of HRG on these cells were evaluated according to cell shape, microcapillary passage, reactive oxygen species (ROS) production, neutrophil extracellular traps (NETs) formation, the expression of activated CD11b, and cell viability. HRG maintained the round shape of differentiated neutrophil-like cells, decreased the time required by cells to pass through the microcapillaries, and inhibited ROS production, NETs formation, and the expression of activated CD11b on the cell surface. Moreover, the cells could survive longer in the presence of HRG than the control. The ATRA-induced differentiated cell lines could be used as alternatives to neutrophils to investigate the effects of HRG on neutrophils. This method can thus be used as an essential standardization test in pharmaceutical development. SIGNIFICANCE STATEMENT: Human neutrophils exhibit varying responses to histidine-rich glycoprotein (HRG); however, all-trans retinoic acid-induced differentiated neutrophil-like cell lines can be used as reliably proxies to investigate the effects of HRG on neutrophils. Additionally, these cell lines can be employed in the development of therapies for the treatment of sepsis.

DOI： 10.1124/jpet.120.000182

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Sepsis is caused by infections associated with life-threatening multiple organ failure (MOF). Septic MOF appears to be closely related to circulatory failure due to immunothrombosis. This process involves the production of reactive oxygen spices (ROS) in inflammatory sites. Therefore, the detoxification of the systemic excess ROS is important for the improvement of the process in septic pathogenesis. Histidine-rich glycoprotein (HRG), a plasma glycoprotein, ameliorates a septic condition through the suppression of both excess ROS production from neutrophils and immunothrombosis. Hydroxyl radical is known as the most important species among ROS in pathogenesis; however, the direct influence of HRG on hydroxyl radical formation and ROS activity is poorly understood. In this study, we showed that HRG, in a concentration-dependent manner, efficiently inhibited the production of hydroxyl radical induced by the Fenton's reaction through chelation of the divalent iron. HRG also exhibited antioxidant activity against peroxyl radical by oxidation of HRG itself as a substrate; however, it did not show superoxide dismutase and catalase-like activities. Additionally, HRG enhanced glutathione peroxidase, a well-known antioxidant enzyme, activity. These results suggest that HRG may play a unique role in suppression of the production of hydroxyl radicals and subsequent tissue damage at inflammatory sites. Marked reduction in plasma HRG in sepsis might lose such an important protective mechanism. Thus, the present study provides evidence that inhibition of ROS and ROS-production systems by HRG may contribute to antiseptic effects in vivo and that HRG could be potential therapy for ROS-related diseases.

DOI： 10.1080/10715762.2020.1825703

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High-mobility group box-1 (HMGB1) protein has been postulated to play a pathogenic role in severe sepsis. Histidine-rich glycoprotein (HRG), a 75 kDa plasma protein, was demonstrated to improve the survival rate of septic mice through the regulation of neutrophils and endothelium barrier function. As the relationship of HRG and HMGB1 remains poorly understood, we investigated the effects of HRG on HMGB1-mediated pathway in endothelial cells, focusing on the involvement of specific receptors for HRG. HRG potently inhibited the HMGB1 mobilization and effectively suppressed rHMGB1-induced inflammatory responses and expression of all three HMGB1 receptors in endothelial cells. Moreover, we first clarified that these protective effects of HRG on endothelial cells were mediated through C-type lectin domain family 1 member A (CLEC-1A) receptor. Thus, current study elucidates protective effects of HRG on vascular endothelial cells through inhibition of HMGB1-mediated pathways may contribute to the therapeutic effects of HRG on severe sepsis.

DOI： 10.1016/j.isci.2020.101180

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A major risk factor for major depressive disorder (MDD) is stress. Stress leads to the release of high-mobility group box-1 (HMGB1), which in turn leads to neuroinflammation, a potential pathophysiological basis of MDD. The mechanism underlying stress-induced HMGB1 release is not known, but stress-associated glucocorticoids could be involved. To test this, rat primary cultured cortical astrocytes, the most abundant cell type in the central nervous system (CNS), were treated with corticosterone and HMGB1 release was assessed by Western blotting and ELISA. Significant HMGB1 was released with treatment with either corticosterone or dexamethasone, a synthetic glucocorticoid. HMGB1 translocated from the nucleus to the cytoplasm following corticosterone treatment. HMGB1 release was significantly attenuated with glucocorticoid receptor blocking. In addition, inhibition of pannexin-1, and P2X7 receptors led to a significant decrease in corticosterone-induced HMGB1 release. Taken together, corticosterone stimulates astrocytic glucocorticoid receptors and triggers cytoplasmic translocation and extracellular release of nuclear HMGB1 through a mechanism involving pannexin-1 and P2X7 receptors. Thus, under conditions of stress, glucocorticoids induce astrocytic HMGB1 release, leading to a neuroinflammatory state that could mediate neurological disorders such as MDD.

DOI： 10.3390/cells9051068

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High mobility group box-1 (HMGB1), a nonhistone chromatin DNA-binding protein, is released from neurons into the extracellular space under ischemic, hemorrhagic, and traumatic insults. However, the details of the time-dependent translocation of HMGB1 and the subcellular localization of HMGB1 through the release process in neurons remain unclear. In the present study, we examined the subcellular localization of HMGB1 during translocation of HMGB1 in the cytosolic compartment using a middle cerebral artery occlusion and reperfusion model in rats. Double immunofluorescence microscopy revealed that HMGB1 immunoreactivities were colocalized with MTCO1(mitochondrially encoded cytochrome c oxidase I), a marker of mitochondria, and catalase, a marker of peroxisomes, but not with Rab5/Rab7 (RAS-related GTP-binding protein), LC3A/B (microtubule-associated protein 1 light chain 3), KDEL (KDEL amino acid sequence), and LAMP1 (Lysosomal Associated Membrane Protein 1), which are endosome, phagosome, endoplasmic reticulum, and lysosome markers, respectively. Immunoelectron microscopy confirmed that immune-gold particles for HMGB1 were present inside the mitochondria and peroxisomes. Moreover, HMGB1 was found to be colocalized with Drp1 (Dynamin-related protein 1), which is involved in mitochondrial fission. These results revealed the specific subcellular localization of HMGB1 during its release process under ischemic conditions.

DOI： 10.3390/cells9030643

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BACKGROUND AND PURPOSE: Microvascular barrier breakdown is a hallmark of sepsis that is associated with sepsis-induced multiorgan failure. Histidine-rich glycoprotein (HRG) is a 75-kDa plasma protein that was demonstrated to improve the survival of septic mice through regulation of cell shape, spontaneous ROS production in neutrophils, and adhesion of neutrophils to vascular endothelial cells. We investigated HRG's role in the LPS/TNF-α-induced barrier dysfunction of endothelial cells in vitro and in vivo and the possible mechanism, to clarify the definitive roles of HRG in sepsis. EXPERIMENTAL APPROACH: EA.hy 926 endothelial cells were pretreated with HRG or human serum albumin before stimulation with LPS/TNF-α. A variety of biochemical assays were applied to explore the underlying molecular mechanisms on how HRG protected the barrier function of vascular endothelium. KEY RESULTS: Immunostaining results showed that HRG maintains the endothelial monolayer integrity by inhibiting cytoskeleton reorganization, losses of VE-cadherin and β-catenin, focal adhesion kinase degradation, and cell detachment induced by LPS/TNF-α. HRG also inhibited the cytokine secretion from endothelial cells induced by LPS/TNF-α, which was associated with reduced NF-κB activation. Moreover, HRG effectively prevented the LPS/TNF-α-induced increase in capillary permeability in vitro and in vivo. Finally, Western blot results demonstrated that HRG prevented the phosphorylation of MAPK family and RhoA activation, which are involved mainly in the regulation of cytoskeleton reorganization and barrier permeability. CONCLUSIONS AND IMPLICATIONS: Taken together, our results demonstrate that HRG has protective effects on vascular barrier function in vitro and in vivo, which may be due to the inhibition of MAPK family and Rho activation.

DOI： 10.1111/bph.14711

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JOHN WILEY & SONS LTD  

Augmentation of natural killer (NK) cell cytotoxicity is one of the greatest challenges for cancer immunotherapy. Although histidine-rich glycoprotein (HRG), a 75-kDa glycoprotein with various immunomodulatory activities, reportedly elicits antitumor immunity, its effect on NK cell cytotoxicity is unclear. We assessed NK cell cytotoxicity against K562 cells. We also measured concentrations of cytokines and granzyme B in the cell supernatant. The proportion of CD56bright NK cells and NK cell surface PD-1 expression was assessed with flow cytometry. The neutralizing effects of anti-C-type lectin-like receptor (CLEC) 1B against HRG were also measured. NK cell morphological changes were analyzed via confocal microscopy. HRG significantly increased NK cell cytotoxicity against K562 cell lines. HRG also increased the release of granzyme B and the proportion of CD56bright NK cells. Further, HRG was able to decrease NK cell surface PD-1 expression. The effects of HRG on NK cells were reversed with anti-CLEC-1B antibodies. Additionally, we confirmed NK cell nuclear morphology and F-actin distribution, which are involved in the regulation of cytotoxic granule secretion. Because both PD-1 and CLEC-1B are associated with prognosis during malignancy, HRG incorporates these molecules to exert the antitumor immunity role. These facts indicate the potential of HRG to be a new target for cancer immunotherapy.

DOI： 10.1002/prp2.481

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPANESE PHARMACOLOGICAL SOC  

Advanced glycation end-products (AGEs) are produced by non-enzymatic glycation between protein and reducing sugar such as glucose. Although glyceraldehyde-derived AGEs (Glycer-AGEs), one of the AGEs subspecies, have been reported to be involved in the pathogenesis of various age-relating diseases such as diabetes mellitus or arteriosclerosis, little is known about the pathological and physiological mechanism of AGEs in vivo. In present study, we produced 4 kinds of polyclonal antibodies against AGEs subspecies and investigated the localization of AGEs-modified proteins in rat peripheral tissues, making use of these antibodies. We found that Glycer-AGEs and methylglyoxal-derived AGEs (MGO-AGEs) were present in pancreatic islets of healthy rats, distinguished clearly into the pancreatic α and β cells, respectively. Although streptozotocin-induced diabetic rats suffered from remarkable impairment of pancreatic islets, the localization and deposit levels of the Glycer- and MGO-AGEs were not altered in the remaining α and β cells. Remarkably, the MGO-AGEs in pancreatic β cells were localized into the insulin-secretory granules. These results suggest that the cell-specific localization of AGEs-modified proteins are presence generally in healthy peripheral tissues, involved in physiological intracellular roles, such as a post-translational modulator contributing to the secretory and/or maturational functions of insulin.

DOI： 10.1016/j.jphs.2017.07.005

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

As one of the most lethal stroke subtypes, intracerebral hemorrhage (ICH) is acknowledged as a serious clinical problem lacking effective treatment. Available evidence from preclinical and clinical studies suggests that inflammatory mechanisms are involved in the progression of ICH-induced secondary brain injury. High mobility group box-1 (HMGB1) is a ubiquitous and abundant nonhistone DNA-binding protein, and is also an important proinflammatory molecule once released into the extracellular space from the nuclei. Here, we show that treatment with neutralizing anti-HMGB1 mAb (1 mg/kg, i.v. twice) remarkably ameliorated ICH-injury induced by local injection of collagenase IV in the striatum of rats. Administration of anti-HMGB1 mAb inhibited the release of HMGB1 into the extracellular space in the peri-hematomal region, reduced serum HMGB1 levels and decreased brain edema by protecting blood-brain barrier integrity, in association with decreased activated microglia and the expression of inflammation-related factors at 24 h after ICH. Consequently, anti-HMGB1 mAb reduced the oxidative stress and improved the behavioral performance of rats. These results strongly indicate that HMGB1 plays a critical role in the development of ICH-induced secondary injury through the amplification of plural inflammatory responses. Intravenous injection of neutralizing anti-HMGB1 mAb has potential as a novel therapeutic strategy for ICH.

DOI： 10.1038/srep46243

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Language：English   Publisher：JAPANESE PHARMACOLOGICAL SOC  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Although delayed cerebral vasospasm (DCV) following subarachnoid hemorrhage (SAH) is closely related to the progression of brain damage, little is known about the molecular mechanism underlying its development. High mobility group box-1 (HMGB1) plays an important role as an initial inflammatory mediator in SAH. In this study, an SAH rat model was employed to evaluate the effects of anti-HMGB1 monoclonal antibody (mAb) on DCV after SAH. A vasoconstriction of the basilar artery (BA) associated with a reduction of nuclear HMGB1 and its translocation in vascular smooth muscle cells were observed in SAH rats, and anti-HMGB1 mAb administration significantly suppressed these effects. Up-regulations of inflammation-related molecules and vasoconstriction-mediating receptors in the BA of SAH rats were inhibited by anti-HMGB1 mAb treatment. Anti-HMGB1 mAb attenuated the enhanced vasocontractile response to thrombin of the isolated BA from SAH rats and prevented activation of cerebrocortical microglia. Moreover, locomotor activity and weight loss recovery were also enhanced by anti-HMGB1 mAb administration. The vasocontractile response of the BA under SAH may be induced by events that are downstream of responses to HMGB1-induced inflammation and inhibited by anti-HMGB1 mAb. Anti-HMGB1 mAb treatment may provide a novel therapeutic strategy for DCV and early brain injury after SAH.

DOI： 10.1038/srep37755

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPANESE PHARMACOLOGICAL SOC  

Acute respiratory distress syndrome (ARDS) is a severe respiratory failure caused by acute lung inflammation. Recently, the receptor for advanced glycation end-products (RAGE) has attracted attention in the lung inflammatory response. However, the function of soluble form of RAGE (sRAGE), which is composed of an extracellular domain of RAGE, in ARDS remains elusive. Therefore, we investigated the dynamics of pulmonary sRAGE and the effects of exogenous recombinant human sRAGE (rsRAGE) under intratracheal lipopolysaccharide (LPS)-induced lung inflammation. Our result revealed that RAGE was highly expressed on the alveolar type I epithelial cells in the healthy rat lung including sRAGE isoform sized 45 kDa. Under LPS-induced injured lung, the release of sRAGE into the alveolar space was increased, whereas the expression of RAGE was decreased with alveolar disruption. Treatment of the injured lung with rsRAGE significantly suppressed the lung edema, the neutrophils infiltration, the release of high mobility group box-1 (HMGB1), and the expressions of TNF-α, IL-1β and iNOS. These results suggest that the alveolar release of sRAGE may play a protective role against HMGB1 as well as exogenous pathogen-associated molecular patterns. Supplementary therapy with sRAGE may be an effective therapeutic strategy for ARDS.

DOI： 10.1016/j.jphs.2016.02.005

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Language：English   Publisher：JAPANESE PHARMACOLOGICAL SOC  

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Language：English   Publisher：JAPANESE PHARMACOLOGICAL SOC  

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Language：English   Publishing type：Research paper (scientific journal)  

OBJECTIVE: To identify and characterize an unknown microorganism causing contamination in several mammalian cell cultures. METHODS: This bacterium was identified by 16S rRNA sequencing and studied by DAPI and DiOC6 (3) staining, Gram staining, acid-fast staining, and electron microscopy. The isolated bacterium was also used to infect host cells to observe antibiotic effectiveness and its relationship with host cells. RESULTS: The 16S rRNA sequence analysis shows that this rod-shaped microorganism belongs to the family Caulobacteraceae, class Alphaproteobacteria, and was most closely related to Phenylobacterium zucineum HLK1T strain. The bacterium collected in the "swimming" stage was Gram staining negative, but Gram staining positive in the "sessile" stage. Under the electron microscope both flagellated and non-flagellated types were found. So far, no antibiotics were effective to inhibit this microorganism. The contamination with this bacterium frequently led to failed resuscitation of thawed cells. We found that the cells resuscitated with the used culture supernatants were increased in number by 3-4 folds as compared to those resuscitated with freshly prepared media. CONCLUSION: Phenylobacterium may have a dimorphic life cycle including a swimming stage and a sessile stalked stage.

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Language：Japanese   Publisher：(公社)日本薬学会  

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J-GLOBAL

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J-GLOBAL

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J-GLOBAL

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J-GLOBAL

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J-GLOBAL

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：JAPANESE PHARMACOLOGICAL SOC  

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Event date： 2018.7.26 - 2018.7.29

Language：English   Presentation type：Oral presentation (general)  

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Event date： 2018.7.1 - 2018.7.6

Language：English   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Oral presentation (general)  

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