High mobility group box 1 in patients with 2009 pandemic H1N1 influenza-associated encephalopathy

Potential significance of high-mobility group protein box 1 in cerebrospinal fluid

High-mobility group protein box 1 (HMGB1) is a cytokine with multiple functions (according to its subcellular location) that serves a marker of inflammation. CSF HMGB1 could be the part of pathological mechanisms that underlie the complications associated with CNS diseases. HMGB1 actively or passively released into the CSF is detected in the CSF in many diseases of the central nervous system (CNS) and thus may be useful as a biomarker. Pathological alterations in distant areas were observed due to lesions in a specific region, and the level of HMGB1 in the CSF was found to be elevated. Reducing the HMGB1 level via intraventricular injection of anti-HMGB1 neutralizing antibodies can improve the outcomes of CNS diseases. The results indicated that CSF HMGB1 could serve as a biomarker for predicting disease progression and may also act as a pathogenic factor contributing to pathological alterations in distant areas following focal lesions in the CNS. In this mini-review, the characteristics of HMGB1 and progress in research on CSF HMGB1 as a biomarker of CNS diseases were discussed. CSF HMGB1 is useful not only as a biomarker of CNS diseases but may also be involved in interactions between different brain regions and the spinal cord.

Serum HMGB1 and soluble urokinase plasminogen activator receptor levels aid diagnosis and prognosis prediction of sepsis with acute respiratory distress syndrome

Objective: To study the clinical application of serum HMGB1 and soluble urokinase plasminogen activator receptor (suPAR) expression in sepsis with acute respiratory distress syndrome (ARDS). Methods: Clinical data of 303 septic patients with/without ARDS were documented. Levels of serum inflammatory markers and HMGB1/suPAR were measured. ARDS patients were subdivided into high and low HMGB1/suPAR expression groups and followed up. Results: Serum HMGB1 and suPAR were upregulated in ARDS patients and positively correlated with inflammatory markers. The combination of HMGB1 with suPAR surpassed HMGB1 or suPAR alone in aiding diagnosis of sepsis with ARDS. CRP, PCT, IL-6, HMGB1 and suPAR were independent risk factors for ARDS. High HMGB1/suPAR expression might be linked to poor prognosis. Conclusion: Serum HMGB1/suPAR levels might aid diagnosis and predict poor prognosis of septic patients with ARDS.

Extracellular HMGB1 as Inflammatory Mediator in the Progression of Mycoplasma Gallisepticum Infection

High-mobility group box 1 (HMGB1), a member of damage-associated molecular patterns (DAMPs), is involved in the immune regulation of several infectious diseases. Mycoplasma gallisepticum (MG) infection is proved to cause an abnormal immune response, but the role of HMGB1 in MG-induced chronic respiratory disease (CRD) is unclear. In this study, we found that HMGB1 was released from the nucleus to the extracellular in macrophages upon infection with MG. Extracellular HMGB1 bound to TLR2 activating the NF-κB pathway triggering a severe inflammatory storm and promoting the progression of MG infection. More importantly, TLR4 could be activated by HMGB1 to trigger immune disorders after TLR2 was silenced. This disease process could be interrupted by ethyl pyruvate (EP) inhibition of HMGB1 release or glycyrrhizic acid (GA). Furthermore, treatment of MG-infected chickens with GA significantly alleviated immune organ damage. In conclusion, we demonstrate that HMGB1 is secreted extracellularly to form an inflammatory environment upon MG infection, triggering a further cellular inflammatory storm in a positive feedback approach. Blocking MG-induced HMGB1 release or suppression downstream of the HMGB1-TLR2/TLR4 axis may be a promising novel strategy for the treatment of CRD. Furthermore, this study may provide a theoretical reference for understanding non-LPS-activated TLR4 events.

Endothelial Dysfunction, HMGB1, and Dengue: An Enigma to Solve

Dengue is a viral infection caused by dengue virus (DENV), which has a significant impact on public health worldwide. Although most infections are asymptomatic, a series of severe clinical manifestations such as hemorrhage and plasma leakage can occur during the severe presentation of the disease. This suggests that the virus or host immune response may affect the protective function of endothelial barriers, ultimately being considered the most relevant event in severe and fatal dengue pathogenesis. The mechanisms that induce these alterations are diverse. It has been suggested that the high mobility group box 1 protein (HMGB1) may be involved in endothelial dysfunction. This non-histone nuclear protein has different immunomodulatory activities and belongs to the alarmin group. High concentrations of HMGB1 have been detected in patients with several infectious diseases, including dengue, and it could be considered as a biomarker for the early diagnosis of dengue and a predictor of complications of the disease. This review summarizes the main features of dengue infection and describes the known causes associated with endothelial dysfunction, highlighting the involvement and possible relationship between HMGB1 and DENV.

Effect of higher body temperature and acute brain edema on mortality in hemorrhagic shock and encephalopathy syndrome

OBJECTIVE

Hemorrhagic shock and encephalopathy syndrome (HSES) is a severe subtype of acute encephalopathy with a poor prognosis. The factors associated with acute neurological outcomes in patients with HSES remain unclear. This study aimed to determine the clinical features, laboratory and radiological findings, and treatments that determine the acute outcomes of HSES.

METHODS

Forty children with HSES registered in a database of Osaka City General Hospital between 1995 and 2020 were included in this observational study. We retrospectively collected data on clinical features, laboratory and radiological items, and treatments. We divided acute neurological outcomes into two groups: the non-death and death groups in 1 week. Correlations were assessed between these items and acute neurological outcomes.

RESULTS

Twenty-seven and 13 patients comprised the non-death and death groups, respectively. Univariate logistic regression analysis showed that higher body temperature, presence of hemorrhagic episode, elevated lactate level, high glucose level in the cerebrospinal fluid, and brain edema at initial computed tomography (CT) were correlated with the death group. Regarding treatments, barbiturate therapy, intravenous immunoglobulin, and intravenous methylprednisolone were significantly initiated in the non-death group. The multivariate logistic regression model showed higher body temperature (odds ratio [OR], 4.210 [1.409-12.584]; p = 0.010) and brain edema on initial head CT (OR, 46.917 [3.995-550.976]; p = 0.002) were independent factors.

CONCLUSIONS

Higher body temperature and brain edema at the onset of HSES were associated with acute outcomes. The results of this study may be useful for treatment planning and acute outcomes in patients with HSES.

Longitudinal electroencephalogram findings predict acute neurological and epilepsy outcomes in patients with hemorrhagic shock and encephalopathy syndrome

OBJECTIVE

Hemorrhagic shock and encephalopathy syndrome (HSES) is a severe subtype of acute encephalopathy with a poor prognosis. The association between electroencephalogram (EEG) findings and neurological outcomes in patients with HSES, including the onset of epilepsy, remains unclear.

METHODS

Thirty-two children with HSES registered in a database of Osaka City General Hospital between 2003 and 2018 were included in this study. The EEG findings which consisted of continuity, reactivity, state change, voltage, rhythmic and periodic patterns, and electrographic or electroclinical seizures, in the onset phase were evaluated for patient outcome. Patients who avoided acute death were investigated for epilepsy by a longitudinal EEG. Seizure types were determined by ictal video recordings.

RESULTS

We analyzed EEG findings in the onset phase of 30 patients. Severely to extremely abnormal EEG pattern (deteriorated continuity more than discontinuous pattern, presence of generalized abnormal low voltage slow wave, and presence of generalized rhythmic and periodic patterns) in the onset phase correlated with poor outcome (p = 0.0024). Subsequently, 9/23 patients (39%) developed epilepsy, of which a total of eight had epileptic spasms. A significant correlation between interictal epileptic discharges and the development of epilepsy was observed as early as within three months (p = 0.0003).

CONCLUSIONS

EEG pattern in the onset phase may be useful to predict the neurological prognosis in the acute stage. Moreover, this study demonstrated that longitudinal EEG findings after the acute phase of HSES were significantly related to the development of epilepsy. EEG findings are useful for predicting acute prognosis and epilepsy in patients with HSES.

Increased circulating levels of High Mobility Group Box 1 (HMGB1) in acute-phase Chikungunya virus infection: Potential disease biomarker

BACKGROUND

Chikungunya virus (CHIKV) causes a febrile syndrome with intense and debilitating arthralgia that can persist for several months or years after complete virus clearance. As there is no specific antiviral treatment or vaccine against CHIKV, identification of serological markers that help clinical management of CHIKV patients is urgent. The High Mobility Group Box 1 (HMGB1) protein is secreted to extracellular milieu and triggers an intense inflammatory process by inducing the overexpression of pro-inflammatory cytokines. HMGB1 plays an important role in several virus diseases as well as in rheumatoid arthritis.

OBJECTIVES

This study focus on the investigation of HMGB1 serum levels in a sera panel from CHIKV-infected patients in an attempt to assess its potential as a biomarker for chikungunya clinical management.

STUDY DESIGN

Eighty CHIKV-positive samples and 32 samples from healthy donors were subjected to a quantitative HMGB1 ELISA assay to assess the HMGB1 circulating levels.

RESULTS

HMGB1 levels were significantly higher in CHIKV-positive samples (516.12 ng/mL, SEM ± 48.83 ng/mL) compared to negative control (31.20 ng/mL, SEM ± 3.24 ng/mL, p < 0.0001). Circulating levels of HMGB1 persisted elevated during the whole acute-phase of disease and correlated with virus titer (p < 0.05).

CONCLUSIONS

The present study is the first to describe increased serum levels of HMGB1 in CHIKV infection and its positive correlation with virus titer, suggesting its potential use as a biomarker for diagnosis and treatment of chikungunya fever.

Transformation of urban mobility during COVID-19 pandemic - Lessons for transportation planning

INTRODUCTION

The coronavirus disease (COVID-19) pandemic is a global threat that started in Wuhan, China, in 2019 and spread rapidly to the globe. To reduce the spread of the COVID-19, different non-pharmacological control measures have been conducted in different countries, which include social distancing, distance working, and stay-at-home mandates. These control measures had affected global transportation and mobility significantly. This study investigated the short-term changes in urban mobility, tropospheric air pollution, and fuel consumption in two major cities of Saudi Arabia, namely, Riyadh and Jeddah.

METHODS

In this study, the dynamics of the number of trips and trip purposes in different provinces of the country were analyzed, focusing on the pandemic period and the lockdown program. These changes impacted fuel consumption and, consequently, air pollutants. The quantity of fuel consumption and its trend was projected considering a few possible fuel consumption and emission scenarios. It is also expected that fuel price plays a role in fuel consumption. The spatial and temporal distributions of the remote sensed tropospheric Nitrogen Dioxide (NO2) levels in different provinces were presented to depict the short 19 and long-term impact on the air quality due to the changes in mobility.

RESULTS

The significant reduction in urban mobility has been observed since the beginning of the first partial curfew in March 2020 compared to that in 2019. The air pollutant levels (such as NO2) in 2020 after the pandemic were generally less than those of 2019. The fuel consumption has been following a decreasing trend in 2020 starting from January due to dynamic fuel price and the additional influence of pandemic. Based on the current online shopping pattern, it is argued that there will be some permanent behavioral changes in urban mobility, which will decrease some shopping trips at least immediately after the recovery from the pandemic.

CONCLUSIONS

This study concluded that the availability of global urban mobility data, remote sensed based tropospheric air pollution data, and global fuel consumption database are important sources of information to investigate the impact of COVID pandemic, especially for the developing countries which suffer from scarcity of pertinent urban mobility information. It seems that, at least in the study area, the spread of COVID-19 is a complex phenomenon in which several exogenous factors, in addition to the curfew protocols, affect the spread of the virus.

MRI findings at neurological onset predict neurological prognosis in hemorrhagic shock and encephalopathy syndrome

BACKGROUND

Hemorrhagic shock and encephalopathy syndrome (HSES) is a devastating disease and has an uncertain pathogenesis. The aim of this study was to predict neurological outcomes for HSES using magnetic resonance imaging (MRI) findings at neurological onset and elucidate the pathophysiology of HSES in the acute phase from serial MRI changes.

MATERIALS AND METHODS

We analyzed the MRI findings of 13 patients who underwent an initial MRI within 24 h of neurological onset. According to neurological prognosis, seven patients were included in the severe group and six in the non-severe group. All patients in the non-severe group had a follow-up MRI. We divided the whole brain into 14 regions and each region was scored according to diffusion-weighted imaging findings. We compared the total scores of each region between the two groups and between onset and follow-up MRI.

RESULTS

At neurological onset, symmetrical lesions were found predominantly in the frontal, parietal, and occipital lobes in 12 of 13 patients (92%). In the severe group, the total score for onset MRI was significantly higher than those in the non-severe group (p = 0.003). The total score was significantly higher for follow-up than those of onset MRI (p = 0.036). White matter lesions that showed a bright tree appearance were observed in the follow-up MRIs of all patients.

CONCLUSION

Total scores for onset MRIs are useful for predicting neurological prognosis in patients with HSES. In addition to widespread cortical involvement of predominantly watershed areas, white matter lesions may play a role in the progression of brain edema.

Potential effects of HMGB1 on viral replication and virus infection-induced inflammatory responses: A promising therapeutic target for virus infection-induced inflammatory diseases

Inflammatory responses, characterized by the overproduction of numerous proinflammatory mediators by immune cells, is essential to protect the host against invading pathogens. Excessive production of proinflammatory cytokines is a key pathogenic factor accounting for severe tissue injury and disease progression during the infection of multiple viruses, which are therefore termed as "cytokine storm". High mobility group box 1 (HMGB1), a ubiquitous DNA-binding protein released either over virus-infected cells or activated immune cells, may act as a proinflammatory cytokine with a robust capacity to potentiate inflammatory response and disease severity. Moreover, HMGB1 is a host factor that potentially participates in the regulation of viral replication cycles with complicated mechanisms. Currently, HMGB1 is regarded as a promising therapeutic target against virus infection. Here, we provide an overview of the updated studies on how HMGB1 is differentially manipulated by distinct viruses to regulate viral diseases.

A Novel Bifunctional Fusion Protein, Vunakizumab-IL22, for Protection Against Pulmonary Immune Injury Caused by Influenza Virus

Influenza A virus infection is usually associated with acute lung injury, which is typically characterized by tracheal mucosal barrier damage and an interleukin 17A (IL-17A)-mediated inflammatory response in lung tissues. Although targeting IL-17A has been proven to be beneficial for attenuating inflammation around lung cells, it still has a limited effect on pulmonary tissue recovery after influenza A virus infection. In this research, interleukin 22 (IL-22), a cytokine involved in the repair of the pulmonary mucosal barrier, was fused to the C-terminus of the anti-IL-17A antibody vunakizumab to endow the antibody with a tissue recovery function. The vunakizumab-IL22 (vmab-IL-22) fusion protein exhibits favorable stability and retains the biological activities of both the anti-IL-17A antibody and IL-22 in vitro. Mice infected with lethal H1N1 influenza A virus and treated with vmab-mIL22 showed attenuation of lung index scores and edema when compared to those of mice treated with saline or vmab or mIL22 alone. Our results also illustrate that vmab-mIL22 triggers the upregulation of MUC2 and ZO1, as well as the modulation of cytokines such as IL-1β, HMGB1 and IL-10, indicating the recovery of pulmonary goblet cells and the suppression of excessive inflammation in mice after influenza A virus infection. Moreover, transcriptome profiling analysis suggest the downregulation of fibrosis-related genes and signaling pathways, including genes related to focal adhesion, the inflammatory response pathway, the TGF-β signaling pathway and lung fibrosis upon vmab-mIL22 treatment, which indicates that the probable mechanism of vmab-mIL22 in ameliorating H1N1 influenza A-induced lung injury. Our results reveal that the bifunctional fusion protein vmab-mIL22 can trigger potent therapeutic effects in H1N1-infected mice by enhancing lung tissue recovery and inhibiting pulmonary inflammation, which highlights a potential approach for treating influenza A virus infection by targeting IL-17A and IL-22 simultaneously.

High mobility group box 1 and angiogenetic growth factor levels in children with central nerve system infections

INTRODUCTION

To clarify the pathology of children with acute encephalopathy and other neurological disorders, the involvement of high-mobility group box 1 (HMGB1), which is a representative of danger-associated molecular patterns, and angiogenesis-related growth factors were investigated.

PATIENTS AND METHODS

Participants were 12 children with acute encephalopathy (influenza, rotavirus, and others), 7 with bacterial meningitis, and 6 with epilepsy disease (West syndrome). Twenty-four patients with non-central nervous system (CNS) infections as a control group were admitted to our hospital. We examined the levels of HMGB1, platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and other cytokines in the serum and cerebrospinal fluid (CSF) of the subjects.

RESULTS

Serum and CSF HMGB1 levels were significantly higher in the encephalopathy and meningitis groups than in the West syndrome and control groups. CSF HMGB1 levels correlated with those of interleukin-6 and -8. CSF HMGB1 and VEGF levels were correlated, and PDGF showed a positive relationship.

CONCLUSION

HMGB1 and angiogenesis-related growth factors appear to play pivotal roles in the pathophysiology of CNS infections.

Time Intervals Between Prior Cervical Conization and Posterior Hysterectomy Influence Postoperative Infection in Patients with Cervical Intraepithelial Neoplasia or Cancer

Background

This study was conducted to observe the influence of different time intervals between prior cervical conization and posterior hysterectomy on postoperative infection in female patients with cervical intraepithelial neoplasia or cancer.

Material/Methods

Medical records of 170 patients who underwent hysterectomy following cervical conization between November 2010 and September 2016 at the Zhenjiang 4^th Hospital were reviewed. According to the interval between hysterectomy and cervical conization, patients were classified into 1–2-week, 4–5-week, and 6-week groups. The outcomes of 46 patients who underwent conization with iodoform gauze inside the vagina were observed.

Results

The total postoperative infection rate after hysterectomy was 25.3% (43/170). The expression levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and high mobility group box 1 (HMGB1) in the cervical secretions and tissues were found to gradually increase, peaking at 2 weeks after conization, then significantly decreasing 3–6 weeks onwards. Compared with the 1–2-week group, the 4–5-week and 6-week groups exhibited significantly lower infection rates (2/42, 4.8%, 4–5-week group; 0%, 0/33, 6-week group; vs. 41/95, 43.2%, 1–2-week group; p<0.001). In the 1–2-week group in particular, the postoperative infection rate after laparoscopic hysterectomy was significantly higher than the rate after abdominal hysterectomy (21/35, 60% vs. 20/60, 33%, p=0.0177). In addition, the vaginal and cervical wound infection rates after conization in patients treated with iodoform were significantly lower than the rates in those without iodoform treatment (p<0.05).

Conclusions

Hysterectomy should be performed at least 4 weeks after conization. Treatment with iodoform would be beneficial.

Anti-high mobility group box-1 monoclonal antibody treatment of brain edema induced by influenza infection and lipopolysaccharide

Encephalopathy is a major cause of influenza-associated child death and severe neurological sequelae in Japan, highlighting the urgent need for new therapeutic strategies. In this study, we evaluated the effects of anti-high mobility group box-1 monoclonal antibody (α-HMGB1) treatment on brain edema induced by influenza A virus (IAV) and lipopolysaccharide in 4-week-old BALB/c female mice. The results showed that administration of 7.5 mg/kg α-HMGB1 1 h after IAV (A/Puerto Rico/8/34) inoculation significantly alleviated brain edema at 48 h after IAV inoculation, as confirmed by the suppression of Evans Blue dye leakage and matrix metallopeptidase-9 mRNA expression in the brain. Moreover, we also observed suppression of oxidative stress and different cytokines in IAV-inoculated mice. The expression of plasminogen activator inhibitor-1 was also attenuated following treatment with α-HMGB1. Notably, α-HMGB1 treatment had no effect on virus propagation in the lung. In summary, anti-HMGB1 treatment may improve the prognosis in cases with influenza-associated encephalopathy by attenuating brain edema and reducing the inflammatory responses induced by HMGB1.

Serum High-Mobility-Group Box 1 as a Biomarker and a Therapeutic Target during Respiratory Virus Infections

Host-derived “danger-associated molecular patterns” (DAMPs) contribute to innate immune responses and serve as markers of disease progression and severity for inflammatory and infectious diseases. There is accumulating evidence that generation of DAMPs such as oxidized phospholipids and high-mobility-group box 1 (HMGB1) during influenza virus infection leads to acute lung injury (ALI). Treatment of influenza virus-infected mice and cotton rats with the Toll-like receptor 4 (TLR4) antagonist Eritoran blocked DAMP accumulation and ameliorated influenza virus-induced ALI. However, changes in systemic HMGB1 kinetics during the course of influenza virus infection in animal models and humans have yet to establish an association of HMGB1 release with influenza virus infection. To this end, we used the cotton rat model that is permissive to nonadapted strains of influenza A and B viruses, respiratory syncytial virus (RSV), and human rhinoviruses (HRVs). Serum HMGB1 levels were measured by an enzyme-linked immunosorbent assay (ELISA) prior to infection until day 14 or 18 post-infection. Infection with either influenza A or B virus resulted in a robust increase in serum HMGB1 levels that decreased by days 14 to 18. Inoculation with the live attenuated vaccine FluMist resulted in HMGB1 levels that were significantly lower than those with infection with live influenza viruses. RSV and HRVs showed profiles of serum HMGB1 induction that were consistent with their replication and degree of lung pathology in cotton rats. We further showed that therapeutic treatment with Eritoran of cotton rats infected with influenza B virus significantly blunted serum HMGB1 levels and improved lung pathology, without inhibiting virus replication. These findings support the use of drugs that block HMGB1 to combat influenza virus-induced ALI.

Influenza virus is a common infectious agent causing serious seasonal epidemics, and there is urgent need to develop an alternative treatment modality for influenza virus infection. Recently, host-derived DAMPs, such as oxidized phospholipids and HMGB1, were shown to be generated during influenza virus infection and cause ALI. To establish a clear link between influenza virus infection and HMGB1 as a biomarker, we have systematically analyzed temporal patterns of serum HMGB1 release in cotton rats infected with nonadapted strains of influenza A and B viruses and compared these patterns with a live attenuated influenza vaccine and infection by other respiratory viruses. Towards development of a new therapeutic modality, we show herein that blocking serum HMGB1 levels by Eritoran improves lung pathology in influenza B virus-infected cotton rats. Our study is the first report of systemic HMGB1 as a potential biomarker of severity in respiratory virus infections and confirms that drugs that block virus-induced HMGB1 ameliorate ALI.

High Mobility Group Box-1 (HMGb1): Current Wisdom and Advancement as a Potential Drug Target

High mobility group box-1 (HMGb1) protein, a nuclear non-histone protein that is released or secreted from the cell in response to damage or stress, is a sentinel for the immune system that plays a critical role in cell survival/death pathways. This review highlights key features of the endogenous danger-associated molecular pattern (DAMP) protein, HMGb1 in the innate inflammatory response along with various cofactors and receptors that regulate its downstream effects. The evidence demonstrating increased levels of HMGb1 in human inflammatory diseases and conditions is presented, along with a summary of current small molecule or peptide-like antagonists proven to specifically target HMGb1. Additionally, we delineate the measures needed toward validating this protein as a clinically relevant biomarker or bioindicator and as a relevant drug target.

Local and Systemic Immune Responses to Influenza A Virus Infection in Pneumonia and Encephalitis Mouse Models

OBJECTIVE

To compare local and systemic profiles between different disease pathologies (pneumonia and encephalitis) induced by influenza A virus (IAV).

METHODS

An IAV pneumonia model was created by intranasal inoculation of C57BL/6 mice with influenza A/WSN/33 (H1N1) virus. Lung lavage and blood collection were performed on day 3 after IAV inoculation. Similarly, an IAV encephalitis mouse model was created by direct intracranial IAV inoculation. Cerebrospinal fluid (CSF) and blood collection were conducted according to the same schedule. Cytokine/chemokine profiles were produced for each collected sample. Then the data were compared visually using radar charts.

RESULTS

Serum cytokine profiles were similar in pneumonia and encephalitis models, but local responses between the bronchoalveolar lavage fluid (BALF) in the pneumonia model and CSF in the encephalitis model differed. Moreover, to varying degrees, the profiles of local cytokines/chemokines differed from those of serum in both the pneumonia and encephalitis models.

CONCLUSION

Investigating local samples such as BALF and CSF is important for evaluating local immune responses, providing insight into pathology at the primary loci of infection. Serum data alone might be insufficient to elucidate local immune responses and might not enable clinicians to devise the most appropriate treatment strategies.

The θ-defensin retrocyclin 101 inhibits TLR4- and TLR2-dependent signaling and protects mice against influenza infection

A member of the θ‐defensin family protects mice during infection with influenza, suggesting a new strategy for viral therapy in humans.

Despite widespread use of annual influenza vaccines, seasonal influenza‐associated deaths number in the thousands each year, in part because of exacerbating bacterial superinfections. Therefore, discovering additional therapeutic options would be a valuable aid to public health. Recently, TLR4 inhibition has emerged as a possible mechanism for protection against influenza‐associated lethality and acute lung injury. Based on recent data showing that rhesus macaque θ‐defensins could inhibit TLR4‐dependent gene expression, we tested the hypothesis that a novel θ‐defensin, retrocyclin (RC)‐101, could disrupt TLR4‐dependent signaling and protect against viral infection. In this study, RC‐101, a variant of the humanized θ‐defensin RC‐1, blocked TLR4‐mediated gene expression in mouse and human macrophages in response to LPS, targeting both MyD88‐ and TRIF‐dependent pathways. In a cell‐free assay, RC‐101 neutralized the biologic activity of LPS at doses ranging from 0.5 to 50 EU/ml, consistent with data showing that RC‐101 binds biotinylated LPS. The action of RC‐101 was not limited to the TLR4 pathway because RC‐101 treatment of macrophages also inhibited gene expression in response to a TLR2 agonist, Pam3CSK4, but failed to bind that biotinylated agonist. Mouse macrophages infected in vitro with mouse‐adapted A/PR/8/34 influenza A virus (PR8) also produced lower levels of proinflammatory cytokine gene products in a TLR4‐independent fashion when treated with RC‐101. Finally, RC‐101 decreased both the lethality and clinical severity associated with PR8 infection in mice. Cumulatively, our data demonstrate that RC‐101 exhibits therapeutic potential for the mitigation of influenza‐related morbidity and mortality, potentially acting through TLR‐dependent and TLR‐independent mechanisms.

HMGB1/RAGE Signaling and Pro-Inflammatory Cytokine Responses in Non-HIV Adults with Active Pulmonary Tuberculosis

BACKGROUND

We aimed to study the pathogenic roles of High-Mobility Group Box 1 (HMGB1) / Receptor-for-Advanced-Glycation-End-products (RAGE) signaling and pro-inflammatory cytokines in patients with active pulmonary tuberculosis (PTB).

METHODS

A prospective study was conducted among non-HIV adults newly-diagnosed with active PTB at two acute-care hospitals (n = 80); age-and-sex matched asymptomatic individuals (tested for latent TB) were used for comparison (n = 45). Plasma concentrations of 8 cytokines/chemokines, HMGB1, soluble-RAGE, and transmembrane-RAGE expressed on monocytes/dendritic cells, were measured. Gene expression (mRNA) of HMGB1, RAGE, and inflammasome-NALP3 was quantified. Patients' PBMCs were stimulated with recombinant-HMGB1 and MTB-antigen (lipoarabinomannan) for cytokine induction ex vivo.

RESULTS

In active PTB, plasma IL-8/CXCL8 [median(IQR), 6.0(3.6-15.1) vs 3.6(3.6-3.6) pg/ml, P<0.001] and IL-6 were elevated, which significantly correlated with mycobacterial load, extent of lung consolidation (rs +0.509, P<0.001), severity-score (rs +0.317, P = 0.004), and fever and hospitalization durations (rs +0.407, P<0.001). IL-18 and sTNFR1 also increased. Plasma IL-8/CXCL8 (adjusted OR 1.12, 95%CI 1.02-1.23 per unit increase, P = 0.021) and HMGB1 (adjusted OR 1.42 per unit increase, 95%CI 1.08-1.87, P = 0.012) concentrations were independent predictors for respiratory failure, as well as for ICU admission/death. Gene expression of HMGB1, RAGE, and inflammasome-NALP3 were upregulated (1.2-2.8 fold). Transmembrane-RAGE was increased, whereas the decoy soluble-RAGE was significantly depleted. RAGE and HMGB1 gene expressions positively correlated with cytokine levels (IL-8/CXCL8, IL-6, sTNFR1) and clinico-/radiographical severity (e.g. extent of consolidation rs +0.240, P = 0.034). Ex vivo, recombinant-HMGB1 potentiated cytokine release (e.g. TNF-α) when combined with lipoarabinomannan.

CONCLUSION

In patients with active PTB, HMGB1/RAGE signaling and pro-inflammatory cytokines may play important roles in pathogenesis and disease manifestations. Our clinico-immunological data can provide basis for the development of new strategies for disease monitoring, management and control.

Modification of p27 with O-linked N-acetylglucosamine regulates cell proliferation in hepatocellular carcinoma

The tumor suppressor p27, which is a member of the Cip/Kip family of Cyclin-dependent kinase inhibitory proteins (CKIs), controls anti-proliferative events. The post-translational addition of O-GlcNAc to p27 occurs in HEK293T and HCC (hepatocellular carcinoma) cell lines, and we identified Ser2, Ser106, Ser110, Thr157, and Thr198 as the glycosylation sites of p27 based on the Q-TOF spectrum. Here, immunoprecipitation analysis showed that Ser2 was O-GlcNAcylated and that this modification was associated with the increased phosphorylation of p27 at Ser10, ultimately resulting in p27 accumulation in the cytoplasm and increased p27 ubiquitination. In addition, O-GlcNAcylation at Ser2 suppressed Cyclin/CDK complex-p27 interactions by promoting the nuclear export of p27, thus facilitating cell cycle progression. Cell proliferation was negatively regulated when Ser2 of p27 was replaced with Ala. Furthermore, western blot and immunohistochemical analyses of HCC tissues and their corresponding nontumorous tissues were performed, and we found that O-GlcNAcylated p27 correlated with cell proliferation in HCC. Together, our results indicate that the dynamic interplay between O-GlcNAcylation and p27 phosphorylation coordinates and regulates cell proliferation in hepatocellular carcinoma. © 2016 Wiley Periodicals, Inc.

Anti-high mobility group box-1 monoclonal antibody treatment provides protection against influenza A virus (H1N1)-induced pneumonia in mice

INTRODUCTION

Provision for the emergence of an influenza pandemic is an urgent issue. The discovery of a novel anti-influenza therapeutic approach would increase the effectiveness of traditional virus-based strategies. This study was undertaken to evaluate the therapeutic effects of anti-high mobility group box-1 (HMGB1) monoclonal antibody (mAb) treatment on influenza A virus (H1N1)-induced pneumonia in mice.

METHODS

Nine-week-old male C57BL/6 mice were inoculated with H1N1, then anti-HMGB1 mAb or control mAb were administered intravenously at 1, 24 and 48 hours after H1N1 inoculation and the survival rate was analyzed. Lung lavage and histopathological analysis were performed on days 3, 5, 7 and 10 after inoculation.

RESULTS

Anti-HMGB1 mAb significantly improved the survival rate of H1N1-inoculated mice (1 out of 15 versus 8 out of 15 deaths in the anti-HMGB1 mAb-treated group versus the control mAb-treated group, p < 0.01), although the treatment did not affect virus propagation in the lungs. The treatment also significantly attenuated histological changes and neutrophil infiltration in the lungs of H1N1-inoculated mice. This was associated with inhibition of HMGB1 and suppression of inflammatory cytokine/chemokine expression and oxidative stress enhancement, which were observed in H1N1-inoculated mice. The expression of receptor for advanced glycation end products and nuclear factor κB was attenuated by the treatment.

CONCLUSIONS

Anti-HMGB1 mAb may provide a novel and effective pharmacological strategy for severe influenza virus infection in humans by reducing the inflammatory responses induced by HMGB1.