Plasma High Mobility Group Box 1 Levels Research Articles

Changes of Damage Associated Molecular Patterns in COVID-19 Patients.

Background:The development of severe coronavirus disease 2019 (COVID-19) is associated with systemic hyperinflammation, which drives multi-organ failure and death. Disease deterioration tends to occur when the virus is receding; however, whether other factors besides viral products are involved in the inflammatory cascade remains unclear.Methods:Twenty-eight COVID-19 patients with laboratory-confirmed SARS-CoV-2 infection hospitalized at the Fifth Medical Center of Chinese PLA General Hospital from January 23 to February 20, 2020 and nine healthy donors during the same period were recruited in the study. COVID-19 patients were grouped as mild, moderate, severe based on disease severity. Plasma damage-associated molecular patterns (DAMPs), including high mobility group box 1 (HMGB1), calprotectin (S100A8/A9), surfactant protein A (SP-A), cold-inducible RNA-binding protein (CIRBP), and Histone H4 were detected by ELISA assay, and analyzed in combination with clinical data. Plasma cytokines, chemokines and lymphocytes were determined by flow cytometry.Results:Plasma levels of HMGB1 (38292.3 ± 4564.4 vs. 32686.3 ± 3678.1, P = 0.002), S100A8/A9 (1490.8 ± 819.3 vs. 742.2 ± 300.8, P = 0.015), and SP-A (6713.6 ± 1708.7 vs. 5296.3 ± 1240.4, P = 0.048) were increased in COVID-19 patients compared to healthy donors, while CIRBP (57.4 ± 30.7 vs. 111.9 ± 55.2, P = 0.004) levels decreased. Five DAMPs did not vary among mild, moderate, and severe patients. Moreover, SP-A levels correlated positively with inflammatory cytokines and negatively with time elapsed after symptom onset, whereas CIRBP showed an opposite pattern.Conclusions:These findings suggest SP-A may involve in the inflammation of COVID-19, while CIRBP likely plays a protective role. Therefore, DAMPs represent a potential target in the prevention or treatment of COVID-19.

Role of high mobility group box 1 in vitiligo

ObjectivesTo assess the role of high-mobility group box 1 (HMGB1) in the pathogenesis of vitiligo patients and its relation to severity of vitiligo.BackgroundVitiligo is a chronic inflammatory disease characterized by skin depigmentation caused by the loss of epidermal melanocytes. Its prevalence ranges between 0.5 and 2%. The pathogenesis of vitiligo is poorly understood.Patients and methodsThis is a case–control study that was conducted on 80 participants, who were divided into two main groups. The first group A included 40 patients with vitiligo. The second group B included 40 age-matched and sex-matched healthy participants as a control group. Blood sample was taken from each participant for measurement of plasma HMGB1 level by the enzyme-linked immunosorbent assay technique.ResultsThe result showed significant increase in the level of plasma HMGB1 in vitiligo patients (79.48 ± 110.5) compared with controls (51.70 ± 69.16) (P = 0.040). The result also showed that HMGB1 concentration was not correlated with clinical parameters such as age, sex, disease onset, duration of recent aggravation, or percentage of vitiligo involvement.ConclusionOur data provide insights into the possible role of HMGB1 for the pathogenesis of vitiligo.

From nicotine to the cholinergic anti-inflammatory reflex – Can nicotine alleviate the dysregulated inflammation in COVID-19?

The coronavirus SARS-CoV-2 of 2019 (COVID-19) causes a pandemic that has been diagnosed in more than 70 million people worldwide. Mild-to-moderate COVID-19 symptoms include coughing, fever, myalgia, shortness of breath, and acute inflammatory lung injury (ALI). In contrast, acute respiratory distress syndrome (ARDS) and respiratory failure occur in patients diagnosed with severe COVID-19. ARDS is mediated, at least in part, by a dysregulated inflammatory response due to excessive levels of circulating cytokines, a condition known as the “cytokine-storm syndrome.” Currently, there are FDA-approved therapies that attenuate the dysregulated inflammation that occurs in COVID-19 patients, such as dexamethasone or other corticosteroids and IL-6 inhibitors, including sarilumab, tocilizumab, and siltuximab. However, the efficacy of these treatments have been shown to be inconsistent. Compounds that activate the vagus nerve-mediated cholinergic anti-inflammatory reflex, such as the α7 nicotinic acetylcholine receptor agonist, GTS-21, attenuate ARDS/inflammatory lung injury by decreasing the extracellular levels of high mobility group box-1 (HMGB1) in the airways and the circulation. It is possible that HMGB1 may be an important mediator of the “cytokine-storm syndrome.” Notably, high plasma levels of HMGB1 have been reported in patients diagnosed with severe COVID-19, and there is a significant negative correlation between HMGB1 plasma levels and clinical outcomes. Nicotine can activate the cholinergic anti-inflammatory reflex, which attenuates the up-regulation and the excessive release of pro-inflammatory cytokines/chemokines. Therefore, we hypothesize that low molecular weight compounds that activate the cholinergic anti-inflammatory reflex, such as nicotine or GTS-21, may represent a potential therapeutic approach to attenuate the dysregulated inflammatory responses in patients with severe COVID-19.

Abstract 5596: Dynamic monitoring of plasma DAMP proteins during multimodal anticancer treatment in advanced lung cancer patients

Abstract Immunogenic cell death characterized by the release of damage-associated molecular patterns (DAMPs) from dying cancer cells is a potential contributor to the synergistic antitumor effects of the combination of cytotoxic chemotherapy with immune checkpoint blockade. However, little information on the kinetics of circulating DAMP levels in cancer patients has been available. We evaluated the possible effects of various anticancer treatment modalities on the kinetics of plasma DAMP proteins in lung cancer patients. In a prospective observational study, plasma concentrations of three representative DAMP proteins–high-mobility group box 1 (HMGB1), calreticulin (CRT), and histone H3–in 50 patients with advanced lung cancer were measured at five time points during the first cycle of anticancer therapy by ELISA assay. The plasma levels of HMGB1 and CRT increased during the first treatment cycle in 42 (84%) and 35 (70%) patients, respectively, with these increases being detectable as early as day 3. The maximum fold changes in HMGB1 and CRT concentrations was associated with clinical response. Among the various treatment modalities, cytotoxic chemotherapy induced the greatest increases in the concentrations of these DAMPs. There was no correlation between the maximum fold changes in the plasma levels of HMGB1 and CRT. Meanwhile, histone H3 was essentially undetectable in most patients. In conclusion, serial monitoring of plasma revealed that anticancer treatment modalities increased the circulating levels of DAMPs with their association with clinical response, suggesting that agents capable of increasing the release of DAMPs into plasma might induce immunogenic cell death in advanced lung cancer patients. Citation Format: Hiroyuki Inoue, Hirono Tsutsumi, Yoshimasa Shiraishi, Koji Okamura, Yoichi Nakanishi, Isamu Okamoto. Dynamic monitoring of plasma DAMP proteins during multimodal anticancer treatment in advanced lung cancer patients [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5596.

High-mobility Group Box 1 Protein in Pediatric Trauma Patients With Acute Traumatic Coagulopathy or Disseminated Intravascular Coagulation

Trauma can induce the release of high-mobility group box 1 (HMGB1), which plays an important role in the activation of coagulation. In this study, we aimed to evaluate the role of HMGB1 in the early diagnosis of acute traumatic coagulopathy (ATC), disseminated intravascular coagulation, and clinical course. One hundred pediatric trauma patients and 50 healthy controls were enrolled. Demographic data, physical examination results, trauma scores, International Society on Thrombosis and Hemostasis score, laboratory values, transfusion requirements, and needs for mechanical ventilation were recorded. Blood samples for HMGB1 were assessed by an enzyme-linked immunosorbent assay. Thirty-five patients had ATC and 3 patients had overt disseminated intravascular coagulation. In trauma patients, HMGB1 levels were statistically higher than those in the control group (P<0.001). There was a positive correlation between HMGB1 levels and D-dimer levels (r=0.589, P<0.001). ATC patients had higher plasma HMGB1 levels than those without ATC (P=0.008). High HMGB1 levels were associated with the duration of mechanical ventilation, need for intensive care unit observation, length of hospital stay, and mortality. This study showed the early increase of HMGB1 in pediatric trauma cases and demonstrated the significant association of high HMGB1 levels with the development of ATC, disseminated intravascular coagulation, trauma severity, clinical outcome, and mortality.

NOD-like receptor protein 3 and high mobility group box-1 are associated with prognosis of patients with congenital heart disease.

ObjectiveTo investigate the association between plasma levels of nucleotide-binding oligomerization domain-like (NOD)-like receptor protein 3 (NLRP3) and high mobility group box-1 (HMGB1) and their prognostic significance in neonatal patients with congenital heart disease (CHD).MethodsThis study enrolled neonatal patients with CHD and collected their demographic and clinical data. Plasma concentrations of NLRP3 and HMGB1 were measured using enzyme-linked immunosorbent assays. Spearman’s analysis was used to determine the correlation between NLRP3 and HMGB1 levels. The association between NLRP3 and HMGB1 levels and 2-year survival and mortality were evaluated using Kaplan–Meier curve and logistic regression analyses.ResultsA total of 84 neonatal patients with CHD were included in the study. Plasma NLRP3 and HMGB1 levels were significantly higher in deceased patients compared with those that survived. There was a positive correlation between NLRP3 and HMGB1 levels in neonatal patients with CHD. Patients with elevated levels of NLRP3 and HMGB1 showed significantly lower 2-year survival and higher mortality rates compared with those with lower NLRP3 and HMGB1 levels.ConclusionNeonatal patients with CHD and a poor prognosis had higher NLRP3 and HMGB1 levels, which suggests that these might be potential biomarkers of CHD prognosis.

HMGB1 Is a Therapeutic Target and Biomarker in Diazepam-Refractory Status Epilepticus with Wide Time Window.

Status epilepticus (SE), a life-threatening neurologic emergency, is often poorly controlled by the current pharmacological therapeutics, which are limited to a narrow time window. Here, we investigated the proinflammatory cytokine high mobility group box-1 (HMGB1) as a candidate therapeutic target for diazepam (DZP)-refractory SE. We found that HMGB1 was upregulated and translocated rapidly during refractory SE period. Exogenous HMGB1 was sufficient to directly induce DZP-refractory SE in nonrefractory SE. Neutralization of HMGB1 with an anti-HMGB1 monoclonal antibody decreased the incidence of SE and alleviated the severity of seizure activity in DZP-refractory SE, which was mediated by a Toll-like receptor 4 (TLR4)-dependent pathway. Importantly, anti-HMGB1 mAb reversed DZP-refractory SE with a wide time window, extending the therapeutic window from 30 to 180 min. Furthermore, we found the upregulation of plasma HMGB1 level is closely correlated with the therapeutic response of anti-HMGB1 mAb in DZP-refractory SE. All these results indicated that HMGB1 is a potential therapeutic target and a useful predictive biomarker in DZP-refractory SE.

Role of non-macrophage cell-derived HMGB1 in oxaliplatin-induced peripheral neuropathy and its prevention by the thrombin/thrombomodulin system in rodents: negative impact of anticoagulants

BackgroundMacrophage-derived high mobility group box 1 (HMGB1), a damage-associated molecular pattern (DAMP) protein, plays a key role in the development of chemotherapy-induced peripheral neuropathy (CIPN) caused by paclitaxel in rodents. Endothelial thrombomodulin (TM) promotes thrombin-induced degradation of HMGB1, and TMα, a recombinant human soluble TM, abolishes peripheral HMGB1-induced allodynia in mice. We thus examined whether HMGB1, particularly derived from macrophages, contributes to oxaliplatin-induced neuropathy in mice and analyzed the anti-neuropathic activity of the TM/thrombin system.MethodsCIPN models were created by the administration of oxaliplatin in mice and rats, and the nociceptive threshold was assessed by von Frey test or paw pressure test. Macrophage-like RAW264.7 cells were stimulated with oxaliplatin in vitro. Proteins were detected and/or quantified by Western blotting, immunostaining, or enzyme-linked immunosorbent assay.ResultsIntraperitoneal administration of an anti-HMGB1-neutralizing antibody (AB) at 1 mg/kg prevented the oxaliplatin-induced allodynia in mice and rats. Antagonists of Toll-like receptor (TLR) 4, receptor for advanced glycation end products (RAGE) and CXCR4 among the HMGB1-targeted pro-nociceptive receptors, also mimicked the anti-neuropathic activity of AB in mice. Macrophage accumulation in the sciatic nerve was observed in mice treated with paclitaxel, but not oxaliplatin, and neither macrophage depletion nor inhibitors of macrophage activation affected oxaliplatin-induced allodynia. Oxaliplatin was 10- to 100-fold less potent than paclitaxel in releasing HMGB1 from macrophage-like RAW264.7 cells. Like AB, TMα at 10 mg/kg prevented the oxaliplatin-induced allodynia in mice as well as rats, an effect abolished by argatroban at 10 mg/kg, a thrombin inhibitor. The anti-neuropathic activity of TMα in oxaliplatin-treated mice was suppressed by oral anticoagulants such as warfarin at 1 mg/kg, dabigatran at 75 mg/kg, and rivaroxaban at 10 mg/kg, but not antiplatelet agents such as aspirin at 50 mg/kg and clopidogrel at 10 mg/kg. Repeated administration of the anticoagulants gradually developed neuropathic allodynia and elevated plasma HMGB1 levels in mice treated with a subeffective dose of oxaliplatin.ConclusionsOur data thus suggests a causative role of HMGB1 derived from non-macrophage cells in oxaliplatin-induced peripheral neuropathy and a thrombin-dependent anti-neuropathic activity of exogenous TMα and, most probably, endogenous TM.

Effect of curcumin on mitochondrial gene and high mobility group box 1 protein in sepsis myocardial injury of rats

Objective To observe the effect of curcumin on myocardial mitochondrial related gene (mtATP6), high mobility group box 1(HMGB1) mRNA expression and plasma HMGB1 level in rats with sepsis, and to explore a new strategy for protection of myocardial injury in sepsis. Methods A rat sepsis model was established by cecal ligation and puncture (CLP). Thirty male Sprague-Dawley rats were randomly (random number) divided into the sham operation group (sham group), sepsis group (CLP group), and curcumin intervention group (Cur group), with 10 rats in each group. Rats in the Cur group were treated with curcumin by intraperitoneal injection at 100 mg/kg, and normal saline was injected into rats in the sham and CLP groups. Five rats were randomly (random number) sacrificed at 6 h and 24 h after modeling. The pathological changes of myocardial tissue were observed under light microscope. The levels of CK and CK-MB in serum were detected. The HMGB1 level in plasma was detected by ELISA. Real-time PCR was used to detect the expression of HMGB1 mRNA and mtATP6 in myocardial tissue. One-way ANOVA were performed in multigroup mean comparison, LSD-t test was used to compare the mean values of two samples, and P<0.05 was considered statistically significant. Results The pathological score of myocardial tissue in the Cur group was lower than those in the CLP group at 6 h and 24 h (P 0.05). Conclusion Curcumin protects acute myocardial injury by affecting HMGB1 release and translocation down-regulation of extracellular levels and regulation of mtATP6 expression in CLP model rats. Key words: Sepsis; Myocardial injury; High mobility group box 1; Mitochondrial gene; Curcumin; Rat

Involvement of high mobility group box 1 in the pathogenesis of severe hemolytic uremic syndrome in a murine model.

Typical hemolytic uremic syndrome is caused by Shiga toxin (Stx2) and lipopolysaccharide (LPS) of Escherichia coli and leads to acute kidney injury. The role of innate immunity in this pathogenesis is unclear. We analyzed the role of high mobility group box 1 (HMGB1) at the onset of disease in a murine model. C57BL/6 mice were intraperitoneally administered saline (group A), anti-HMGB1 monoclonal antibody (group B), Stx2 and LPS to elicit severe disease (group C), or Stx2, LPS, and anti-HMGB1 antibody (group D). While all mice in group C died by day 5 of the experiment, all mice in group D survived. Anemia and thrombocytopenia were pronounced and plasma creatinine levels were significantly elevated in group C only at 72 h. While at 72 h after toxin administration the glomerulus tissue in group C showed pathology similar to that of humans, mesangial cell proliferation was seen in group D. Plasma HMGB1 levels in group C peaked 3 h after administration and were higher than those in other groups. Expression of the receptor of advanced glycation end products and NF-κB, involved in HMGB1 signaling, was significantly elevated in group C but not in group D. Administration of anti-HMGB1 antibody in a murine model of severe disease inhibited plasma HMGB1 and promoted amelioration of tissue damage. HMGB1 was found to be involved in the disease pathology; therefore, controlling HMGB1 activity might inhibit disease progression.

High-Mobility Group Box 1 Is Associated with the Inflammatory Pathogenesis of Graves' Orbitopathy.

Background: High-mobility group box 1 (HMGB1) has been implicated in the pathogenesis of inflammatory autoimmune diseases. This study investigated the influence and mechanisms of HMGB1 in Graves' orbitopathy (GO). Methods: HMGB1 and its receptors (receptor for advanced glycation end products [RAGE], Toll-like receptor [TLR] 2, and TLR4) mRNA levels were evaluated by real-time polymerase chain reaction (RT-PCR) in GO and non-GO orbital tissues. The mRNA expressions of HMGB1 and its receptors were evaluated in primary cultured orbital fibroblasts from six GO patients and five healthy control subjects under interleukin (IL)-1β or tumor necrosis factor (TNF)-α stimulation using RT-PCR. HMGB1 secretions under IL-1β or TNF-α stimulation were evaluated by enzyme-linked immunosorbent assay (ELISA). The effects of an anti-HMGB1 antibody, RAGE antagonist (FPS-ZM1), and anti-TLR2 antibody on the expressions of IL-1β or TNF-α induced pro-inflammatory cytokines and phosphorylated nuclear factor kappa-light-chain-enhancer of activated B cells were evaluated using ELISA and Western blot analysis, respectively. The plasma levels of HMGB1 were compared among patients with active GO (n = 51), inactive GO (n = 48), Graves' disease without GO (n = 30), and healthy control subjects (n = 46) by ELISA. Results: The genes encoding HMGB1 and its receptors, as well as HMGB1 protein expression, were increased in GO orbital tissues compared to non-GO tissues. IL-1β and TNF-α stimulation increased the mRNA levels of HMGB1, RAGE, and TLR2 and the secretion of HMGB1 protein further in GO cells. Anti-HMGB1 antibody, FPS-ZM1, and anti-TLR2 antibody reduced IL-1β- or TNF-α-induced production of pro-inflammatory cytokines and phosphorylated nuclear factor kappa-light-chain-enhancer of activated B cells. The plasma levels of HMGB1 were highly increased in patients with active GO, and were significantly correlated with the clinical activity score (r = 0.566, p = 0.002) and levels of thyrotropin binding inhibitory immunoglobulin (r = 0.506, p < 0.001). Conclusions: This study demonstrates an association of HMGB1 and its receptors in the inflammatory mechanisms of GO. HMGB1, RAGE, and TLR2 blockers reduced the production of pro-inflammatory molecules, providing a rationale for blocking the HMGB1 pathway to treat patients with GO. HMGB1 proteins were secreted further in the plasma of patients with active GO, suggesting that HMGB1 can be used as a biomarker of GO activity.

NRP1 regulates HMGB1 in vascular endothelial cells under high homocysteine condition

Endothelial inflammation plays an important role in hyperhomocysteinemia (HHcy)-associated vascular diseases. High mobility group box 1 (HMGB1) is a pro-inflammatory danger molecule produced by endothelial cells. However, whether HMGB1 is involved in vascular endothelial inflammation of HHcy is poorly understood. Neuropilin-1 (NRP1) mediates inflammatory response and activates mitogen-activated protein kinases (MAPKs) pathway that has been reported to be involved in regulation of HMGB1. The aim of this study was to determine the alteration of HMGB1 in HHcy, and the role of NRP1 in regulation of endothelial HMGB1 under high homocysteine (Hcy) condition. In the present study, we first observed that the plasma level of HMGB1 was elevated in HHcy patients and an experimental rat model, and increased HMGB1 was also observed in the thoracic aorta of an HHcy rat model. HMGB1 was induced by Hcy accompanied with upregulated NRP1 in vascular endothelial cells. Overexpression of NRP1 promoted expression and secretion of HMGB1 and endothelial inflammation; knockdown of NRP1 inhibited HMGB1 and endothelial inflammation induced by Hcy, which partially regulated through p38 MAPK pathway. Furthermore, NRP1 inhibitor ATWLPPR reduced plasma HMGB1 level and expression of HMGB1 in the thoracic aorta of HHcy rats. In conclusion, our data suggested that Hcy requires NRP1 to regulate expression and secretion of HMGB1. The present study provides the evidence for inhibition of NRP1 and HMGB1 to be the novel therapeutic targets of vascular endothelial inflammation in HHcy in the future. NEW & NOTEWORTHY This study shows for the first time to our knowledge that the plasma level of high mobility group box 1 (HMGB1) is elevated in hyperhomocysteinemia (HHcy) patients, and homocysteine promotes expression and secretion of HMGB1 partially regulated by neuropilin-1 in endothelial cells, which is involved in endothelial inflammation. Most importantly, these new findings will provide a potential therapeutic strategy for vascular endothelial inflammation in HHcy.

Elucidating the novel biomarker and therapeutic potentials of High-mobility group box 1 in Subarachnoid hemorrhage: A review.

Subarachnoid hemorrhage (SAH) frequently arises after an aneurysm in a cerebral artery ruptures, resulting into bleeding as well as clot formation. High-mobility group box 1 (HMGB1) is an extremely preserved, universal protein secreted in the nuclei of all cell varieties. This review explores the biomarker as well as therapeutic potentials of HMBG1 in SAH especially during the occurrence of cerebral vasospasms. Plasma HMGB1 levels have proven to be very useful prognosticators of effective outcome as well as death after SAH. Correspondingly, higher HMGB1 levels in the cerebrospinal fluid (CSF) of SAH patients correlated well with poor outcome; signifying that, CSF level of HMGB1 is a novel predictor of outcome following SAH. Nonetheless, the degree of angiographic vasospasm does not always correlate with the degree of neurological deficits in SAH patients. HMGB1 stimulated cerebral vasospasm, augmented gene as well as protein secretory levels of receptor for advance glycation end product (RAGE) in neurons following SAH; which means that, silencing HMGB1 during SAH could be of therapeutic value. Compounds like resveratrol, glycyrrhizin, rhinacanthin, purpurogallin, 4′-O-β-D-Glucosyl-5-O-Methylvisamminol (4OGOMV) as well as receptor-interacting serine/threonine-protein kinase 3 (RIPK3) gene are capable of interacting with HMGB1 resulting in therapeutic benefits following SAH.

Role of Receptors for Advanced Glycation End Products and High-Mobility Group Box 1 in the Outcome of Human T Cell Lymphotropic Type 1 Infection

Human T cell lymphotropic type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic viral neuroinflammatory disease, which leads to damage of the central nervous system. Inflammatory responses and mediators are both involved in the pathogenesis of the disease and in determining its outcome. High-Mobility Group Box 1 (HMGB1) is a chromatin-associated nuclear protein acting as a signaling molecule in cells after binding to its receptors. Receptor for advanced glycation end products (RAGE) is a transmembrane multiligand receptor that binds to HMGB1. HMGB1-RAGE signaling has an important role in inflammatory and infectious diseases. Inhibition of HMGB1 activity reduces the inflammation in immune-associated diseases. In the present study, we examined the gene expressions and plasma levels of HMGB1 and its receptor RAGE in HAM/TSP patients, HTLV-1-infected asymptomatic carriers (ACs), and healthy controls. Peripheral blood mononuclear cells were collected from all the groups and complementary DNA (cDNA) was synthesized. HMGB-1 messenger RNA (mRNA) expression was quantified by real-time polymerase chain reaction (PCR) TaqMan method, and plasma levels of HMGB1 and soluble RAGE (sRAGE) were measured by enzyme-linked immunosorbent assay (ELISA). The mRNA expression of HMGB1 was the same among the groups (p > 0.05). No significant difference in the plasma levels of HMGB1 was observed between the groups (p > 0.05). The plasma levels of sRAGE were higher in ACs than HAM/TSP patients, and a significant difference was observed between the two groups (p < 0.001). Our results showed that sRAGE could play a potential role in the control of inflammatory response in HTLV-1 carriers through the inhibition of HMGB1 signaling and potentially could be used as an indicator for evaluation of HAM/TSP developing in HTLV-1-infected individuals.

Anti–High Mobility Group Box 1 Antibody Therapy May Prevent Cognitive Dysfunction After Traumatic Brain Injury

High mobility group box 1 (HMGB1) protein plays a key role in triggering inflammatory responses in many diseases. Our previous study showed that HMGB1 is found upstream of secondary damage in traumatic brain injury (TBI). We found that anti-HMGB1 monoclonal antibody (mAb) effectively decreased acute brain damage, including the disruption of the blood-brain barrier, brain edema, and neurologic dysfunction. This effect of anti-HMGB1 mAb lasts for at least 1 week. In this study, we explored subacute effects of anti-HMGB1 mAb after TBI. TBI was induced in rats by fluid percussion. Anti-HMGB1 mAb or control mAb was given intravenously after TBI. Histochemical staining, plasma levels of HMGB1, motor activity and memory, and video electroencephalography monitoring were evaluated 2 weeks after fluid percussion injury. Anti-HMGB1 mAb remarkably attenuated accumulation of activated microglia in the rat cortex in the ipsilateral hemisphere after TBI. Anti-HMGB1 mAb also prevented neuronal death in the hippocampus in the ipsilateral hemisphere after TBI. Treatment of rats with anti-HMGB1 mAb inhibited HMGB1 translocation and suppressed impairment of motor function. The beneficial effects of anti-HMGB1 mAb on motor and cognitive function persisted for 14 days after injury. Treatment with anti-HMGB1 mAb also had positive effects on electroencephalography activity. The beneficial effects of anti-HMGB1 mAb continued during the subacute postinjury phase, suggesting that anti-HMGB1 mAb may prevent cognitive dysfunction after TBI.

High HMGB1 levels in sputum are related to pneumococcal bacteraemia but not to disease severity in community-acquired pneumonia

During bacterial infections, damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs) activate immune cells. Here, we investigated whether plasma and sputum levels of High Mobility Group Box 1 (HMGB1), a prototypic DAMP, are associated with disease severity and aetiology in community-acquired pneumonia (CAP). In addition, in patients with pneumococcal CAP, the impact of the level of sputum lytA DNA load, a PAMP, was investigated. We studied patients hospitalised for bacterial CAP (n = 111), and samples were collected at admission. HMGB1 was determined by enzyme-linked immunosorbent assays, and pneumococcal lytA DNA load was determined by quantitative polymerase chain reaction. Plasma and sputum HMGB1 levels did not correlate to disease severity (pneumonia severity index or presence of sepsis), but high sputum HMGB1 level was correlated to pneumococcal aetiology (p = 0.002). In pneumococcal pneumonia, high sputum lytA DNA load was associated with respiratory failure (low PaO2/FiO2 ratio; p = 0.019), and high sputum HMGB1 level was associated with bacteraemia (p = 0.006). To conclude, high sputum HMGB1 was not associated with severe disease, but with pneumococcal bacteraemia, indicating a potential role for HMGB1 in bacterial dissemination. High sputum lytA was associated with severe disease.

Sirt1 S-nitrosylation induces acetylation of HMGB1 in LPS-activated RAW264.7 cells and endotoxemic mice

Excessive inflammation plays a detrimental role in endotoxemia. A recent study indicated that alarmins such as high mobility group box 1 (HMGB1) have drawn attention as therapeutic targets of sepsis. Post-translational modification (i.e., acetylation of lysine residues) of HMGB1 leads to the release of HMGB1 into the cellular space, operating as a warning signal that induces inflammation. Sirtuin 1 (SIRT1) has been shown to negatively regulate HMGB1 hyperacetylation and its extracellular release in sepsis. Therefore, we hypothesized that the S-nitrosylation (SNO) of SIRT1 may disrupt the ability of SIRT1 to negatively regulate the hyperacetylation of HMGB1. As long as the S-nitrosylation of SIRT1 occurs during septic conditions, it may worsen the situation. We found that the activity of SIRT1 decreased as the SNO-SIRT1 levels increased, resulting in HMGB1 release by LPS in RAW264.7 cells. Both the iNOS inhibitor (1400 W) and silencing iNOS significantly inhibited SNO-SIRT1, allowing increases in SIRT1 activity that decreased the HMGB1 release by LPS. SNAP, a NO donor, significantly increased both SNO-SIRT1 levels and the HMGB1 release that was accompanied by decreased sirt1 activity. However, sirtinol, a Sirt1 inhibitor, by itself decreased Sirt1 activity compared to that of the control, so that it did not affect already increased SNO-SIRT levels by SNAP. Most importantly, in lung tissues of LPS-endotoxic mice, significantly increased levels of SNO-SIRT were found, which was inhibited by 1400 W treatment. Plasma nitrite and HMGB1 levels were significantly higher than those in the sham controls, and the elevated levels were significantly lowered in the presence of 1400 W. We concluded that the S-nitrosylation of Sirt1 under endotoxic conditions may uninhibit the acetylation of HMGB1 and its extracellular release.

Preterm Life in Sterile Conditions: A Study on Preterm, Germ-Free Piglets.

Preterm infants born with immature organ systems, which can impede normal development, can also be highly sensitive to different biological and/or environmental factors. Animal models could aid in investigating and understanding the effects of different conditions on the health of these immunocompromised infants. The epitheliochorial placentation of the pig prevents the prenatal transfer of protective colostral immunoglobulins. Surgical colostrum-deprived piglets are free of maternal immunoglobulins, and the cells that are normally provided via colostrum. We bred preterm germ-free piglets in sterile conditions and compared them with their term counterparts. Enterocyte development and intestinal morphology, tight junction proteins claudin-1 and occludin, pattern-recognizing receptors, adaptor molecules and coreceptors (RAGE, TLR2, TLR4, TLR9, MyD88, TRIF, MD2, and CD14), and inflammasome NLRP3 transcription were all evaluated. The production of inflammatory mediators IFN-α, IL-4, IL-6, IL-8, IL-10, IL-12/23 p40, TNF-α, IFN-γ, and high mobility group box 1 (HMGB1) in the intestine of germ-free piglets was also assessed. In the preterm germ-free piglets, the ileum showed decreased lamina propria cellularity, reduced villous height, and thinner and less distinct stratification – especially muscle layer, in comparison with their term counterparts. Claudin-1 transcription increased in the intestine of the preterm piglets. The transcription levels of pattern-recognizing receptors and adaptor molecules showed ambiguous trends between the groups. The levels of IL-6, IL-8, IL-10, and TNF-α were increased in the preterm ileum numerically (though not significantly), with statistically significant increases in the colon. Additionally, IL-12/23 p40 and IFN-γ were statistically significantly higher in the preterm colon. Both blood plasma and intestinal HMGB1 levels were nonsignificantly higher in the preterm group. We propose that the intestine of the preterm germ-free piglets showed “mild inflammation in sterile conditions.” This model, which establishes preterm, hysterectomy-derived germ-free piglets, without protective maternal immunoglobulins, can be used to study influences of microbiota, nutrition, and therapeutic interventions on the development and health of vulnerable immunocompromised preterm infants.

Epigenetic anticancer agents cause HMGB1 release in vivo

ABSTRACTA systematic search for anticancer agents that may induce the release of high mobility group box 1 (HMGB1) protein from cells into the extracellular space has led to the identification of several drugs capable of elevating plasma HMGB1 levels in vivo, in mice. Such agents include bona-fide immunogenic cell death inducers such as oxaliplatin, as well as a series of epigenetic modifiers, namely azacitidine, decitabine, and suberoylanilide hydroxamic acid (SAHA).

High-mobility group box 1, early activity marker in lupus nephritis

Objectives Systemic lupus erythematosus is an autoimmune disease characterized by the involvement of multiple organ systems. High-mobility group box 1 (HMGB1) is a nuclear nonhistone protein secreted by many cells during activation or cell death. We aim to study the potential pathogenetic role of HMGB1 in lupus and whether urinary, serum, and renal biopsy levels reflect renal inflammation and correlate with disease activity. Patients and methods In a case–control study, 61 systemic lupus patients and 18 healthy volunteers were divided into four groups. Group 1 included 21 patients with lupus nephritis (LN). Group 2 included 21 patients with lupus activity without nephritis. Group 3 included 19 patients without activity. Group 4 included 18 healthy volunteers who were age and sex matched. Participants were subjected to assessment of history, physical examination, activity scoring using SLE disease activity index (SLEDAI), and laboratory investigations including plasma and urinary levels of HMGB1 by enzyme-linked immunosorbent assay. Study of the HMGB1 immunohistochemical expression pattern in renal biopsy was carried out in group 1. Results Plasma and urinary HMGB1 levels and the renal tissue extranuclear expression (cytoplasmic and extracellular) pattern of HMGB1 were significantly increased in patients with active LN compared with the other groups (P Conclusion HMGB1 plays an important role in the pathogenesis of LN and reflects disease activity. Thus, HMGB1 can be utilized as a biomarker for renal disease activity in patients with lupus and the therapeutic value of HMGB1-blocking agents must be investigated.