Emerging role of HMGB1 in lung diseases: friend or foe

The role of polydatin in inhibiting oxidative stress through SIRT1 activation: A comprehensive review of molecular targets

ETHNOPHARMACOLOGICAL RELEVANCE

Reynoutria japonica Houtt is a medicinal plant renowned for its diverse pharmacological properties, including heat-clearing, toxin-removing, blood circulation promotion, blood stasis removal, diuretic action, and pain relief. The plant is commonly utilized in Traditional Chinese Medicine (TCM), and its major bioactive constituents consist of polydatin (PD) and resveratrol (RES).

AIM OF THE STUDY

To summarize the relevant targets of PD in various oxidative stress-related diseases through the activation of Silence information regulator1 (SIRT1). Furthermore, elucidating the pharmacological effects and signaling mechanisms to establish the basis for PD's secure clinical implementation and expanded range of application.

MATERIALS AND METHODS

Literature published before November 2023 on the structural analysis and pharmacological activities of PD was collected using online databases such as Google Scholar, PubMed, and Web of Science. The keywords were "polydatin", "SIRT1" and "oxidative stress". The inclusion criteria were research articles published in English, including in vivo and in vitro experiments and clinical studies. Non-research articles such as reviews, meta-analyses, and letters were excluded.

RESULTS

PD has been found to have significantly protective and curative effects on diseases associated with oxidative stress by regulating SIRT1-related targets including peroxisome proliferator-activated receptor γ coactivator 1-alpha (PGC-1α), nuclear factor erythroid2-related factor 2 (Nrf2), high mobility group box 1 protein (HMGB1), NOD-like receptor thermal protein domain associated protein 3 (NLRP3), p38/p53, as well as endothelial nitric oxide synthase (eNOs), among others. Strong evidence suggests that PD is an effective natural product for treating diseases related to oxidative stress.

CONCLUSION

PD holds promise as an effective treatment for a wide range of diseases, with SIRT1-mediated oxidative stress as its potential pathway.

Role of microRNA-505 during tumor progression and metastasis

Late diagnosis of cancer in advanced stages due to the lack of screening methods is considered as the main cause of poor prognosis and high mortality rate among these patients. Therefore, it is necessary to investigate the molecular tumor biology in order to introduce biomarkers that can be used in cancer screening programs and early diagnosis. MicroRNAs (miRNAs) have key roles in regulation of the cellular pathophysiological processes. Due to the high stability of miRNAs in body fluids, they are widely used as the non-invasive tumor markers. According to the numerous reports about miR-505 deregulation in a wide range of cancers, we investigated the role of miR-505 during tumor progression. It was shown that miR-505 mainly has the tumor suppressor functions through the regulation of signaling pathways, chromatin remodeling, and cellular metabolism. This review has an effective role in introducing miR-505 as a suitable marker for the early cancer diagnosis.

Immune Dysregulation in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a disease whose incidence increase with age and is characterised by chronic inflammation and significant immune dysregulation. Inhalation of toxic substances cause oxidative stress in the lung tissue as well as airway inflammation, under the recruitment of chemokines, immune cells gathered and are activated to play a defensive role. However, persistent inflammation damages the immune system and leads to immune dysregulation, which is mainly manifested in the reduction of the body's immune response to antigens, and immune cells function are impaired, further destroy the respiratory defensive system, leading to recurrent lower respiratory infections and progressive exacerbation of the disease, thus immune dysregulation play an important role in the pathogenesis of COPD. This review summarizes the changes of innate and adaptive immune-related cells during the pathogenesis of COPD, aiming to control COPD airway inflammation and improve lung tissue remodelling by regulating immune dysregulation, for further reducing the risk of COPD progression and opening new avenues of therapeutic intervention in COPD.

The activation of SIRT1 ameliorates BPDE-induced inflammatory damage in BEAS-2B cells via HMGB1/TLR4/NF-κB pathway

Benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE), the metabolite of environmental pollutant benzo(a)pyrene (B(a)P) could induce pulmonary toxicity and inflammation. SIRT1, an NAD+ -dependent histone deacetylase, is known to regulate inflammation in the occurrence and development of various diseases, but its effects on BPDE-induced acute lung injury are still unknown. The present study aimed to explore the role of SIRT1 in BPDE-induced acute lung injury. Here, human bronchial epithelial (HBE) cells (BEAS-2B) cells were stimulated with BPDE at different concentrations (0.50, 0.75, and 1.00 μmol/L) for 24 h, we found that the levels of cytokines in the supernatant were increased and the expression of SIRT1 in cells was down-regulated, at the same time, BPDE stimulation up-regulated the protein expression of HMGB1, TLR4, and p-NF-κBp65 in BEAS-2B cells. Then the activator and inhibitor of SIRT1 were used before BPDE exposure, it was shown that the activation of SIRT1 significantly attenuated the levels of inflammatory cytokines and HMGB1, and reduced the expression of HMGB1, AC-HMGB1, TLR4, and p-NF-κBp65 protein; while these results were reversed by the inhibition of SIRT1. This study revealed that the SIRT1 activation may protect against BPDE-induced inflammatory damage in BEAS-2B cells by regulating the HMGB1/TLR4/NF-κB pathway.

Effect of HMGB1 and HBD-3 levels in the diagnosis of sepsis- A comparative descriptive study

Sepsis is a life-threatening condition characterized by a dysregulated host response to infection. Early and accurate diagnosis of sepsis is crucial for timely intervention and improved patient outcomes. In recent years, there has been growing interest in identifying reliable biomarkers to aid in the diagnosis of sepsis. This study aims to evaluate the levels of two potential biomarkers, high-mobility group box 1 (HMGB1) and human β-defensin 3 (HBD-3), and compare their diagnostic efficacy in sepsis. We aimed to assess HMGB-1 and HBD-3 levels in sepsis and assess the combined diagnostic validity of HMGB-1 and HBD-3. In this case-control study, the plasma concentration of HMGB-1 and HBD-3 was measured using an enzyme-linked immunosorbent assay (ELISA). Two groups, totaling 144 people, were formed; 66 patients treated in the ICU for sepsis were included in the patient group. 78 Blood donors from the Salmaniya Medical Complex Blood Bank who had no prior infection or inflammatory disease made up the Control group. The statistical computations were performed using the STATA 8® statistical software tool (StataCorp LP, College Station, TX, USA). In patients' mean HMGB-1 levels were 2.1442 ng/ml, compared to 0.62141 ng/ml in the control group. The mean HBD-3 level was 1068.453 ng/ml in sepsis patients versus 589.935 ng/ml in controls. A significant difference between the two groups has been observed in both biomarkers (P < 0.05). The sensitivity of HMGB-1 was 75.8% and 41.3%, respectively. The sensitivity and specificity of HBD-3 were 63.6% and 93.5%, respectively. The levels of HMGB-1 and HBD-3 between healthy and septic subjects varied significantly. HMGB-1 and HBD-3 levels in the blood tested together might accurately identify sepsis. These findings contribute to the growing body of evidence supporting the utility of biomarkers in sepsis diagnosis, and may ultimately aid in the development of more effective diagnostic strategies for sepsis management.

Advanced Biomarkers of Hepatotoxicity in Psychiatry: A Narrative Review and Recommendations for New Psychoactive Substances

One of the factors that increase the effectiveness of the pharmacotherapy used in patients abusing various types of new psychoactive substances (NPSs) is the proper functioning of the liver. However, the articles published to date on NPS hepatotoxicity only address non-specific hepatic parameters. The aim of this manuscript was to review three advanced markers of hepatotoxicity in psychiatry, namely, osteopontin (OPN), high-mobility group box 1 protein (HMGB1) and glutathione dehydrogenase (GDH, GLDH), and, on this basis, to identify recommendations that should be included in future studies in patients abusing NPSs. This will make it possible to determine whether NPSs do indeed have a hepatotoxic effect or whether other factors, such as additional substances taken or hepatitis C virus (HCV) infection, are responsible. NPS abusers are at particular risk of HCV infection, and for this reason, it is all the more important to determine what factors actually show a hepatotoxic effect in them.

Dimerization of Transmembrane Proteins in Cancer Immunotherapy

Transmembrane proteins (TMEMs) are integrated membrane proteins that span the entire lipid bilayer and are permanently anchored to it. TMEMs participate in various cellular processes. Some TMEMs usually exist and perform their physiological functions as dimers rather than monomers. TMEM dimerization is associated with various physiological functions, such as the regulation of enzyme activity, signal transduction, and cancer immunotherapy. In this review, we focus on the dimerization of transmembrane proteins in cancer immunotherapy. This review is divided into three parts. First, the structures and functions of several TMEMs related to tumor immunity are introduced. Second, the characteristics and functions of several typical TMEM dimerization processes are analyzed. Finally, the application of the regulation of TMEM dimerization in cancer immunotherapy is introduced.

Biological impact of sequential exposures to allergens and ultrafine particle-rich combustion aerosol on human bronchial epithelial BEAS-2B cells at the air liquid interface

The prevalence of allergic diseases is constantly increasing since few decades. Anthropogenic ultrafine particles (UFPs) and allergenic aerosols is highly involved in this increase; however, the underlying cellular mechanisms are not yet understood. Studies observing these effects focused mainly on singular in vivo or in vitro exposures of single particle sources, while there is only limited evidence on their subsequent or combined effects. Our study aimed at evaluating the effect of subsequent exposures to allergy-related anthropogenic and biogenic aerosols on cellular mechanism exposed at air-liquid interface (ALI) conditions. Bronchial epithelial BEAS-2B cells were exposed to UFP-rich combustion aerosols for 2 h with or without allergen pre-exposure to birch pollen extract (BPE) or house dust mite extract (HDME). The physicochemical properties of the generated particles were characterized by state-of-the-art analytical instrumentation. We evaluated the cellular response in terms of cytotoxicity, oxidative stress, genotoxicity, and in-depth gene expression profiling. We observed that single exposures with UFP, BPE, and HDME cause genotoxicity. Exposure to UFP induced pro-inflammatory canonical pathways, shifting to a more xenobiotic-related response with longer preincubation time. With additional allergen exposure, the modulation of pro-inflammatory and xenobiotic signaling was more pronounced and appeared faster. Moreover, aryl hydrocarbon receptor (AhR) signaling activation showed to be an important feature of UFP toxicity, which was especially pronounced upon pre-exposure. In summary, we were able to demonstrate the importance of subsequent exposure studies to understand realistic exposure situations and to identify possible adjuvant allergic effects and the underlying molecular mechanisms.

The protective role of HMGB1 in affecting the balance between autophagy and pyroptosis to maintain neutrophils homeostasis during β-glucan-induced mice lung inflammation

Fungal contamination is omnipresent, and inhalation of fungi-contaminated organic dust leads to hypersensitivity pneumonitis (HP), in which neutrophils played a pivotal role. Existing studies have suggested that cell homeostasis is crucial for the pathogenesis of the inflammatory disease. Although HMGB1 has been shown to contribute to suppressing HP, there is a lack of studies on its mechanisms, especially the regulation of neutrophil homeostasis. This study aims to investigate how HMGB1 regulates neutrophil function by affecting neutrophil homeostasis, and then affects lung inflammation induced by β-glucan, the exposure marker of fungi. Our results showed that deficient HMGB1 led to neutrophil death by disrupting the balance between autophagy and pyroptosis after β-glucan treatment. And HMGB1 deficiency exacerbated the β-glucan-induced lung inflammation and neutrophil dysfunction both in vivo and in vitro. Furthermore, HMGB1 contributed to remodeling neutrophil function by restricting autophagy and aggravating pyroptosis β-glucan exposure. Our funding suggested that HMGB1 deficiency could break the balance between autophagy and pyroptosis towards pyroptosis to cause neutrophil dysfunction during the exacerbated inflammatory response, which provides insights into the pathogenesis of HP and the potential biological targets for its treatment. DATA AVAILABILITY: The datasets used during the current study are available from the corresponding author on reasonable request.

Relationship between severe acute respiratory syndrome coronavirus 2 and diabetes mellitus (review)

Infections caused by SARE-CoV-2 are complicated with the concurrent pathologies, to name hypertension, diabetes mellitus and cardiovascular diseases. High level of glucose in blood weakens the immunity and increase the SARS-CoV-2 replication. Diabetes mellitus aggravates the COVID-19 outcome. The intrusion of SARS-CoV-2 into a host-cell occurs by means of its association with the angiotensin-converting enzyme-2 (ACE 2). Stimulating immune responses the COVID-19 infection causes the cytokine storm, and may result in the lethal outcome in the diabetics.

Recent laboratory studies demonstrated that the type1 and type2 diabetes mellitus is the main consequence in 14% of the patients after corona infection. Thus, in 2% of 14% diabetes started progressing due to the corona virus. In the other, diabetes debut occurred as the direct and negative consequence of the disease. Hyperglycemia results in the formation of protein molecules known as the advanced glycation end products (AGEs). The AGEs and their receptors (RAGE) are of high significance in the host-cell’s virus invasion. Consequently, more strict glucose control is necessary for optimal outcome and reduction in mortality. The better control for the COVID-19 course can be provided by the targeted effect on the RAGE axis. The review helps elucidate the molecular mechanism underlying the exacerbation of pathophysiology in the diabetic COVID-19 patients.

Acute liver injury induced by carbon tetrachloride reversal by Gandankang aqueous extracts through nuclear factor erythroid 2-related factor 2 signaling pathway

The aims of this study were to evaluated the effect and underlying mechanism of Gandankang (GDK) aqueous extract in alleviating the acute liver injury induced by carbon tetrachloride (CCl₄) in vivo and in vitro. Mice were divided into 5 groups (n = 8) for acute (Groups: control, 0.3 % CCl₄, BD (Bifendate), 1.17, 2.34 and 4.68 mg/kg GDK) liver injury study. 10 µL/g CCl₄ with corn oil were injected interperitoneally (i.p) expect the control group. HepG2 cells were used in vitro study. The results showed GDK can effectively inhibit liver damage and restore the structure and function of the liver. In mechanism, GDK inhibited CCl₄-induced liver fibrosis and blocked the NF-κB pathway to effectively inhibit the hepatic inflammatory response; and inhibited CCl₄-induced oxidative stress by upregulating the Keap1/Nrf2 pathway-related proteins and promoting the synthesis of several antioxidants. Additionally, it inhibited ferroptosis in the liver by regulating the expression of ACSl4 and GPX4. GDK reduced lipid peroxide generation in vitro by downregulating the production of reactive oxygen species and Fe²⁺ aggregation, thereby inhibiting ferroptosis and alleviating CCl₄-induced hepatocyte injury. In conclusion, we describe the potential complex mechanism underlying the effect of GDK against acute liver injury.

Integrated analysis of methylation profiles and transcriptome of MDV-infected chicken spleens reveal hypomethylation of CD4 and HMGB1 genes might promote MD tumorigenesis

Marek's disease (MD) is a lymphoproliferative neoplastic disease caused by Marek's disease virus (MDV). Previous studies have showed that DNA methylation was involved in MD development, but systematic studies are still lacking. Herein, we performed whole genome bisulfite sequencing (WGBS) and RNA-seq in MDV-infected tumorous spleens (IN), noninfected spleens (NoIN), and survivor (SUR) spleens of chickens to identify the genes playing important roles in MD tumor transformation. We generated the first genome-wide DNA methylation profile of MDV-infected, noninfected, and survivor chickens. Combined the WGBS and RNA-Seq, we found that the expression of 25% differential expression genes (DEGs) were significantly correlated with methylation of CpG sites in their gene bodies or promoters. Further, we focused on the DEGs with differentially methylated regions (DMRs) on genes' body and promoter, and it showed the expression of 60% DEGs were significantly correlated with methylation of CpG sites in DMRs. Finally, we identified 8 genes, including CD4, CTLA4, DTL, HMGB1, LGMN, NUP210, RAD52, and ZAP70, and their expression was negatively correlated with methylation of DMRs in their promoters in both IN vs. NoIN and IN vs. SUR. These 8 genes showed specifically high expression in IN groups and clustered in module turquoise analyzed by WGCNA. Out of 8 genes, CD4 and HMGB1 were drop in QTLs associated with MD resistance. Thus, we overexpressed the 2 genes to simulate their high expression in the IN group and found they significantly promoted MDCC-MSB-1 cell proliferation, which revealed they might play promoting roles in MD tumorigenesis in IN due to their high expression induced by hypomethylation.

Repositioning itraconazole for amelioration of bleomycin-induced pulmonary fibrosis: Targeting HMGB1/TLR4 Axis, NLRP3 inflammasome/NF-κB signaling, and autophagy

BACKGROUND AND AIMS

Bleomycin (BLM) is one of the antitumor medications that had proven efficacy in the treatment of a wide range of malignant conditions. Pulmonary fibrosis which is frequently encountered during the course of bleomycin therapy may significantly reduce the potential efficacy of bleomycin in cancer therapy. This study tested the hypothesis that itraconazole may have mitigating effects on BLM-induced pulmonary fibrosis and tried to delineate the potential mechanisms of these effects.

MATERIALS AND METHODS

In a rat model of pulmonary fibrosis elicited by BLM, the effect of different doses of itraconazole was explored at the biochemical, histopathological, and electron microscopic levels.

KEY FINDINGS

Itraconazole, in a dose-dependent manner, exhibited significant effects on the pro-oxidant/antioxidant balance, the inflammatory consequences, high-mobility group box 1/toll-like receptor-4 Axis, autophagy and nuclear factor kappa B/Nod-like receptor protein 3 inflammasome signaling and alleviated the histopathological, immunohistochemical, and electron microscopic perturbations induced by BLM in the pulmonary tissues.

SIGNIFICANCE

In view of the afore-mentioned data, itraconazole may be a promising drug that efficiently mitigates the deleterious effects of BLM on the pulmonary tissues.

Protective Effects of Sophorae tonkinensis Gagnep. (Fabaceae) Radix et Rhizoma Water Extract on Carbon Tetrachloride-Induced Acute Liver Injury

Sophorae tonkinensis Radix et Rhizoma (STR) is a traditional Chinese herbal medicine. STR can reduce aminotransferase activity; however, the specific mechanism remains unclear. Here, we explored the potential therapeutic effects and hepatoprotective mechanism of STR on liver damage in mice. The chemical characteristics of the extract were characterized using ultra-high-performance liquid chromatography-tandem mass spectrometry fingerprinting, and its antioxidant capacity was verified using free radical scavenging tests. Forty-eight Kunming mice were randomly assigned into six groups. The model was made after the corresponding drug was given. The results showed that the STR water extract pretreatment significantly reduced serum aminotransferase and related liver function indicators compared with that in the model group. Furthermore, the STR water extract pretreatment significantly inhibited the apoptosis of liver cells, the level of liver high-mobility group box 1 (HMGB1), and inflammatory factors in hepatic tissue compared with that in the model group, and significantly downregulated the levels of toll-like receptor 4 (TLR4), Myeloid differentiation factor 88 (MyD88), and nuclear factor kappa B (NF-κB) compared with those in the model group. Overall, the STR water extract exerted a significant protective effect on CCL₄-induced acute liver injury in this study, and the accurate active ingredients of the STR water extract will be explored in the near future.

Glycyrrhizin Interacts with TLR4 and TLR9 to Resolve P. aeruginosa Keratitis

This study tests the mechanism(s) of glycyrrhizin (GLY) protection against P. aeruginosa keratitis. Female C57BL/6 (B6), TLR4 knockout (TLR4KO), myeloid specific TLR4KO (mTLR4KO), their wildtype (WT) littermates, and TLR9 knockout (TLR9KO) mice were infected with P. aeruginosa KEI 1025 and treated with GLY or PBS onto the cornea after infection. Clinical scores, photography with a slit lamp, RT-PCR and ELISA were used. GLY effects on macrophages (Mϕ) and polymorphonuclear neutrophils (PMN) isolated from WT and mTLR4KO and challenged with KEI 1025 were also tested. Comparing B6 and TLR4KO, GLY treatment reduced clinical scores and improved disease outcome after infection and decreased mRNA expression levels in cornea for TLR4, HMGB1, and RAGE in B6 mice. TLR9 mRNA expression was significantly reduced by GLY in both mouse strains after infection. GLY also significantly reduced HMGB1 (B6 only) and TLR9 protein (both B6 and TLR4KO). In TLR9KO mice, GLY did not significantly reduce clinical scores and only slightly improved disease outcome after infection. In these mice, GLY significantly reduced TLR4, but not HMGB1 or RAGE mRNA expression levels after infection. In contrast, in the mTLR4KO and their WT littermates, GLY significantly reduced corneal disease, TLR4, TLR9, HMGB1, and RAGE corneal mRNA expression after infection. GLY also significantly reduced TLR9 and HMGB1 corneal protein levels in both WT and mTLR4KO mice. In vitro, GLY significantly lowered mRNA expression levels for TLR9 in both Mϕ and PMN isolated from mTLR4KO or WT mice after incubation with KEI 1025. In conclusion, we provide evidence to show that GLY mediates its effects by blocking TLR4 and TLR9 signaling pathways and both are required to protect against disease.

Inhibition of inflammatory liver injury by the HMGB1-A box through HMGB1/TLR-4/NF-κB signaling in an acute liver failure mouse model

We aimed to investigate the preventive effect of high mobility group box 1 (HMGB1)-A box and the mechanism by which it alleviates inflammatory injury in acute liver failure (ALF) by inhibiting the extracellular release of HMGB1. BALB/c mice were intraperitoneally (i.p.) administered LPS/D-GalN to establish an ALF mouse model. HMGB1-A box was administered (i.p.) 1 h before establishing the ALF mouse model. The levels of extracellularly released HMGB1, TLR-4/NF-κB signaling molecules, the proinflammatory cytokines TNF-α, IL-1β, and IL-6 and COX-2 were measured in the liver tissue and/or serum by Immunohistochemistry, Western blotting and Enzyme-linked immunosorbent assay (ELISA). The levels of extracellularly released HMGB1, TLR-4/NF-κB signaling molecules and proinflammatory cytokines were measured in Huh7 cells as well as LPS- and/or HMGB1-A box treatment by confocal microscopy, Western blotting and ELISA. In the ALF mouse model, the levels of HMGB1 were significantly increased both in the liver and serum, TLR-4/NF-κB signaling molecules and proinflammatory cytokines also was upregulated. Notably, HMGB1-A box could reverse these changes. HMGB1-A box could also cause these changes in LPS-induced Huh7 cells. HMGB1-A box played a protective role by inhibiting inflammatory liver injury via the regulation of HMGB1/TLR-4/NF-κB signaling in the LPS/D-GaIN-induced ALF mouse model, which may be related to inhibiting the extracellular release of HMGB1.

The role of HMGB1/RAGE/TLR4 signaling pathways in cigarette smoke-induced inflammation in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a common chronic respiratory disease with irreversible and continuous progression. It has become the fifth most burdensome disease and the third most deadly disease globally. Therefore, the prevention and treatment of COPD are urgent, and it is also important to clarify the pathogenesis of it. Smoking is the main and most common risk factor for COPD. Cigarette smoke (CS) can cause lung inflammation and other pathological mechanisms in the airways and lung tissue. Airway inflammation is one of the important mechanisms leading to the pathogenesis of COPD. Recent studies have shown that high mobility group box 1 (HMGB1) is involved in the occurrence and development of respiratory diseases, including COPD. HMGB1 is a typical damage-associated molecular pattern (DAMP) protein, which mainly exerts its activity by binding to the receptor for advanced glycation end products (RAGE) and toll-like receptor 4 (TLR4) and further participate in the process of airway inflammation. Studies have shown that the abnormal expression of HMGB1, RAGE, and TLR4 are related to inflammation in COPD. Herein, we discuss the roles of HMGB1, RAGE, and TLR4 in CS/cigarette smoke extract-induced inflammation in COPD, providing a new target for the diagnosis, treatment and prevention of COPD.

Focus on long non-coding RNA MALAT1: Insights into acute and chronic lung diseases

Acute lung injury (ALI) is a pulmonary illness with a high burden of morbidity and mortality around the world. Chronic lung diseases also represent life-threatening situations. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a type of long non-coding RNA (lncRNA) and is highly abundant in lung tissues. MALAT1 can function as a competitive endogenous RNA (ceRNA) to impair the microRNA (miRNA) inhibition on targeted messenger RNAs (mRNAs). In this review, we summarized that MALAT1 mainly participates in pulmonary cell biology and lung inflammation. Therefore, MALAT1 can positively or negatively regulate ALI and chronic lung diseases (e.g., chronic obstructive pulmonary disease (COPD), bronchopulmonary dysplasia (BPD), pulmonary fibrosis, asthma, and pulmonary hypertension (PH)). Besides, we also found a MALAT1-miRNA-mRNA ceRNA regulatory network in acute and chronic lung diseases. Through this review, we hope to cast light on the regulatory mechanisms of MALAT1 in ALI and chronic lung disease and provide a promising approach for lung disease treatment.

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.

TLR2, TLR4, and NLRP3 mediated the balance between host immune-driven resistance and tolerance in Staphylococcus aureus-infected mice

Staphylococcus aureus (S. aureus) is a gram-positive pathogen that can cause infectious diseases in mammals. S. aureus-induced host innate immune responses have a relationship with Toll-like receptor 2 (TLR2), TLR4, and Nod-like receptor pyrin domain-containing protein 3 (NLRP3). However, the detailed roles of TLR2, TLR4, and NLRP3 in regulating the host inflammatory response to S. aureus infection remain unclear. Our data indicated that the S. aureus-induced mortality was aggravated by deficiency of TLR2, TLR4, and NLRP3 in mice. In the subsequent experiment, we found that during S. aureus infection, the roles of TLR2, TLR4, and NLRP3 seemed to be different at multiple timepoints. The deficiency of TLR2, TLR4, or NLRP3 attenuated the expression of High-mobility group box protein 1 (HMGB1) and Hyaluronic acid-binding protein 2 (HABP2), which is accompanied by decreased proinflammatory cytokine (TNF-α), chemokine (RANTES), and anti-inflammatory cytokine (IL-10) production in lungs and serum at 3 h and 6 h post-infection. However, with S. aureus infection prolonged (24 h post-infection), the trend was diametrically opposite. The results showed that deficiency of TLR2, TLR4, or NLRP3 aggravated HABP2 and HMGB1 expression, which is accompanied by enhanced proinflammatory cytokine (TNF-α), chemokine (RANTES), and anti-inflammatory cytokine (IL-10) production in lungs and serum. These results were consistent with the data observed in S. aureus-infected bone marrow-derived macrophages (BMDMs). All these results suggested that during S. aureus infection, TLR2, TLR4, and NLRP3 has time-dependent effect in regulating the balance between immune-driven resistance and tolerance.

Soluble Receptor for Advanced Glycation End Product Is Involved in the Inflammatory Response of Human Adenovirus-Infected Patients

Human adenovirus (HAdV) infection causes excessive inflammation associated with severe tissue injury, such as pneumonia. The molecules involved in the underlying inflammatory mechanisms remain to be elucidated. Receptor for advanced glycation end product (RAGE) is mainly expressed on immune cells and lung tissues, and it is a key factor in the initiation and development of inflammation. RAGE can be cleaved by metalloprotease 9 (MMP9) to release the extracellular segment, which is named soluble RAGE (sRAGE), into the intercellular space, where it can bind to RAGE ligands and block RAGE activation and subsequent inflammation. In our study, we enrolled HAdV-infected patients and their contacts to examine the relationship between sRAGE and inflammation induced by HAdV infection. The results showed that HAdV infection stimulated inflammatory cytokine secretion, increased such as high mobility group box 1 (HMGB1) levels, and suppressed sRAGE expression. sRAGE levels were significantly different between patients with or without pneumonia. We also found that MMP9 was significantly lower in patients with pneumonia, and it was positively correlated with sRAGE levels over 7 days after disease onset. The mitogen-activated protein kinase (MAPK) pathway is an important immune activation signaling pathway that is regulated by RAGE. We observed the activation of the MAPK pathway in the peripheral blood mononuclear cells (PBMCs) of patients. Negative correlations between sRAGE and phosphorylated JNK and p38 were observed. These results suggest that sRAGE is involved in HAdV-induced inflammatory responses, and might be a potential therapeutic target to alleviate the HAdV-induced excessive inflammation.

Pathogenic Mechanisms of Secondary Organic Aerosols

Air pollution represents a major health problem and an economic burden. In recent years, advances in air pollution research has allowed particle fractionation and identification of secondary organic aerosol (SOA). SOA is formed from either biogenic or anthropogenic emissions, through a mass transfer from the gaseous mass to the particulate phase in the atmosphere. They can have deleterious impact on health and the mortality of individuals with chronic inflammatory diseases. The pleiotropic effects of SOA could involve different and interconnected pathogenic mechanisms ranging from oxidative stress, inflammation, and immune system dysfunction. The purpose of this review is to present recent findings about SOA pathogenic roles and potential underlying mechanisms focusing on the lungs; the latter being the primary exposed organ to atmospheric pollutants.

Mesenchymal stem cells inhibited the apoptosis of alveolar epithelial cells caused by ARDS through CXCL12/CXCR4 axis

Mesenchymal stem cells (MSCs) have a wide range of anti-inflammatory and immunomodulatory effects and have been observed to have potential therapeutic potential in the clinical treatment of various diseases. We pretreated lung cancer cells A549 with tumor necrosis factor (TNF-α), knocked down the key chemokine receptor CXCR4 on MSCs using lentivirus, and induced acute respiratory distress syndrome (ARDS) mouse model using lipopolysaccharide (LPS) and CXCL12 expression in vivo by adeno-associated virus (AAV-rh10) infection in mice. By co-culturing the MSCs with A549 and in vivo experiments, we observed the effects of MSCs on cell biological functions after inflammatory stimulation, oxidative stress, and the amelioration of lung injury in ARDS mice. TNF-α inhibited A549 proliferation and promoted apoptosis, scorch death-related factor activity, and oxidative stress factor were increased and CXCL12 levels in the cell supernatant were decreased. The co-culture of MSCs was able to increase cell activity and decrease oxidative stress factor levels, and this effect was not present after the knockdown of CXCR4 in MSCs. In vivo transplantation of MSCs significantly attenuated lung injury in ARDS, inhibited serum pro-inflammatory factors in mice, and down-regulated expression of apoptotic and focal factors in lung tissues while blocking CXCR4 or CXCL12 lost the repairing effect of MSCs on ARDS lung tissues. After the co-culture of MSC and lung cancer cells, the expression of CXCR4 on the surface of lung cancer cells was significantly increased, and more CXCR4 and CXCL12 acted together to activate more pro-survival pathways and inhibit apoptosis induced by TNF-α.

High mobility group box-1 (HMGB-1) and its receptors in the pathogenesis of malaria-associated acute lung injury/acute respiratory distress syndrome in a mouse model

The DNA-binding protein high mobility group box-1 (HMGB-1) mediates proinflammatory cytokines that contribute to acute lung injury (ALI). Although ALI is a frequent complication of malaria infection, the contribution of HMGB-1 and its receptors to the pathogenesis of malaria-associated ALI/acute respiratory distress syndrome (MA-ALI/ARDS) has not been investigated in a mouse model. Here, the malaria-infected mice were divided into two groups according to lung injury score: the ALI/ARDS and non-ALI/ARDS groups. The expression of HMGB-1 and its receptors (RAGE, TLR-2 and TLR-4) in lung tissues was investigated by using immunohistochemical staining and real-time polymerase chain reaction (PCR). Additionally, HMGB-1 and proinflammatory cytokine (TNF-α, IFN-γ, IL-1 and IL-6) levels in plasma and lung tissues were quantified by using enzyme-linked immunosorbent assays. Cellular expression of both HMGB-1 and its receptors (RAGE, TLR-2 and TLR-4) was significantly increased in the lung tissues of the ALI/ARDS group compared with those in the non-ALI/ARDS and control groups. The levels of HMGB-1, TNF-α, IFN-γ, IL-1 and IL-6 were significantly increased in both plasma and lung tissues of the ALI/ARDS group compared with those in the non-ALI/ARDS and control groups, which were similar to the results obtained by real-time PCR. Increased mRNA expression of RAGE, TLR-2 and TLR-4 was found in the lung tissues of the ALI/ARDS group. Furthermore, the plasma HMGB-1 level was positively correlated with TLR-4 mRNA expression in the ALI/ARDS group. HMGB-1 levels were significantly increased in plasma and lung tissues of MA-ALI/ARDS mice and were related to the upregulated expression of HMGB-1 and proinflammatory cytokines. In conclusion, this study demonstrates that HMGB-1 is an important mediator of MA-ALI/ARDS pathogenesis and may represent a target for therapeutic malaria interventions with ALI/ARDS.

Protective Effect of an Anti-HMGB-1 Neutralizing Antibody on Hemozoin-Induced Alveolar Epithelial Cell in a Model of Malaria Associated ALI/ARDS

Background:

We aimed to determine whether neutralizing high mobility group box-1 (HMGB-1) prevents the release of HMGB-1 and proinflammatory cytokines on hemozoin (Hz)-induced alveolar epithelial cell in a model of malaria associated ALI/ARDS.

Methods:

This study was conducted in the Department of Tropical Pathology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand in 2020. Human pulmonary alveolar epithelial cells (HPAEpiCs) were exposed to medium alone or 20 μM Hz for 24 h and incubated with different concentrations (1, 5, and 10 μg/ml) of anti-HMGB-1 monoclonal antibody (mAb) for various times (0, 4, 12, 24, and 48 h). The levels of HMGB-1, TNF-α and IFN-γ in the supernatants were measured by ELISA. The mRNA expression of RAGE, TLR-2 and TLR-4 were analyzed by real-time PCR.

Results:

The HPAEpiCs treated with 10 μg/ml anti-HMGB-1 mAb showed a significant reduction in HMGB-1 release into the supernatant compared with those treated with 1 and 5 μg/ml anti-HMGB-1 mAb. The levels of TNF-α and IFN-γ were significantly decreased in the supernatant of HPAEpiCs treated with 1, 5, and 10 μg/ml anti-HMGB-1 mAb for 4, 12, 24, and 48 h compared with those stimulated with Hz alone. The mRNA expression levels of RAGE, TLR-2, and TLR-4 were significantly decreased after 24 h of anti-HMGB-1 antibody treatment at all concentrations.

Conclusion:

An anti-HMGB-1 antibody could be an effective agent for inhibiting the release of HMGB-1, TNF-α and IFN-γ. Furthermore, a neutralizing anti-HMGB-1 antibody could be applicable for the treatment of malaria-associated ALI/ARDS.

HMGB1 could restrict 1,3-β-glucan induced mice lung inflammation by affecting Beclin1 and Bcl2 interaction and promoting the autophagy of epithelial cells

Fungi were microorganisms that are ubiquitous in a variety of environments. Inhalation of fungi-contaminated organic dust led to hypersensitivity pneumonitis and might eventually cause irreversible pulmonary fibrosis. Studies showed that maintaining the homeostasis of epithelial cells was vital for defending the exogenous fungi invasion. HMGB1-dependent autophagy played a critical role in maintaining cell homeostasis in multiple inflammatory diseases. However, the actual role of HMGB1-dependent autophagy in hypersensitivity pneumonitis was unclear. In our study, mice were exposed to 0.3 mg/50 μL 1,3-β-glucan solution by intratracheal instillation to set up the lung inflammation model. To investigate the role of HMGB1-dependent autophagy in 1,3-β-glucan induced lung inflammation, AAV-sh-HMGB1 was intratracheally injected to silence HMGB1 in the lung. Our finding suggested that silencing HMGB1 could aggravate the 1,3-β-glucan induced lung inflammation by inhibiting the autophagy of epithelial cells. And ubiquitination of Beclin1 contributed to decreasing the interaction of Beclin1 and Bcl2, which might be a key regulatory mechanism of HMGB1 on 1,3-β-glucan induced autophagy.

HMGB1-RAGE Pathway Contributes to the Abnormal Migration of Endogenous Subventricular Zone Neural Progenitors in an Experimental Model of Focal Microgyria

Abnormal migration of subventricular zone (SVZ)-derived neural progenitor cells (SDNPs) is involved in the pathological and epileptic processes of focal cortical dysplasias (FCDs), but the underlying mechanisms are not clear. Recent studies indicated that high mobility group box 1 (HMGB1)/receptor for advanced glycation end products (RAGE) are widely expressed in epileptic specimens of FCDs, which suggests that the HMGB1-RAGE pathway is involved in the pathological and/or epileptic processes of FCDs. The present study used Nestin-GFP^tg/+ transgenic mice, and we established a model of freezing lesion (FL), as described in our previous report. A "migrating stream" composed of GFP-Nestin⁺ SDNPs was derived from the SVZ region and migrated to the cortical FL area. We found that translocated HMGB1 and RAGE were expressed in cortical lesion in a clustered distribution pattern, which was especially obvious in the early stage of FL compared to the sham group. Notably, the number of GFP-Nestin⁺ SDNPs within the "migrating stream" was significantly decreased when the HMGB1-RAGE pathway was blocked by a RAGE antagonist or deletion of the RAGE gene. The absence of RAGE also decreased the activity of pentylenetetrazol-induced cortical epileptiform discharge. In summary, this study provided experimental evidence that the levels of extranuclear HMGB1 and its receptor RAGE were increased in cortical lesion in the early stage of the FL model. Activation of the HMGB1-RAGE pathway may contribute to the abnormal migration of SDNPs and the hyperexcitability of cortical lesion in the FL model.

Inhibition of Oxidative Stress and ALOX12 and NF-κB Pathways Contribute to the Protective Effect of Baicalein on Carbon Tetrachloride-Induced Acute Liver Injury

This study investigates the protective effect of baicalein on carbon tetrachloride (CCl₄)-induced acute liver injury and the underlying molecular mechanisms. Mice were orally administrated baicalein at 25 and 100 mg/kg/day for 7 consecutive days or ferrostatin-1 (Fer-1) at 10 mg/kg was i.p. injected in mice at 2 and 24 h prior to CCl₄ injection or the vehicle. Our results showed that baicalein or Fer-1 supplementation significantly attenuated CCl₄ exposure-induced elevations of serum alanine aminotransferase and aspartate aminotransferase, and malondialdehyde levels in the liver tissues and unregulated glutathione levels. Baicalein treatment inhibited the nuclear factor kappa-B (NF-κB) pathway, activated the erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) pathway in liver tissues, and markedly improved CCl₄-induced apoptosis, inflammation and ferroptosis in liver tissues exposed with CCl₄. In vitro, baicalein treatment improved CCl₄ -induced decreases of cell viabilities and knockdown of Nrf2 and arachidonate 12-lipoxygenase (ALOX12) genes partly abolished the protective effect of baicalein on CCl₄ -induced cytotoxicity in HepG2 cells. In conclusion, our results reveal that baicalein supplementation ameliorates CCl₄-induced acute liver injury in mice by upregulating the antioxidant defense pathways and downregulating oxidative stress, apoptosis, inflammation and ferroptosis, which involved the activation of Nrf2 pathway and the inhibition of ALOX12 and NF-κB pathways.

Role of Atypical Chemokines and Chemokine Receptors Pathways in the Pathogenesis of COPD

Chronic obstructive pulmonary disease (COPD) represents a heightened inflammatory response in the lung generally resulting from tobacco smoking-induced recruitment and activation of inflammatory cells and/or activation of lower airway structural cells. Several mediators can modulate activation and recruitment of these cells, particularly those belonging to the chemokines (conventional and atypical) family. There is emerging evidence for complex roles of atypical chemokines and their receptors (such as high mobility group box 1 (HMGB1), antimicrobial peptides, receptor for advanced glycosylation end products (RAGE) or toll-like receptors (TLRs)) in the pathogenesis of COPD, both in the stable disease and during exacerbations. Modulators of these pathways represent potential novel therapies for COPD and many are now in preclinical development. Inhibition of only a single atypical chemokine or receptor may not block inflammatory processes because there is redundancy in this network. However, there are many animal studies that encourage studies for modulating the atypical chemokine network in COPD. Thus, few pharmaceutical companies maintain a significant interest in developing agents that target these molecules as potential antiinflammatory drugs. Antibody-based (biological) and small molecule drug (SMD)-based therapies targeting atypical chemokines and/or their receptors are mostly at the preclinical stage and their progression to clinical trials is eagerly awaited. These agents will most likely enhance our knowledge about the role of atypical chemokines in COPD pathophysiology and thereby improve COPD management.

Could Targeting HMGB1 be Useful for the Clinical Management of COVID-19 Infection?

Since the high mobility group box-1 (HMGB1) molecule had been recognized as a proinflammatory cytokine, which mediates endotoxin lethality of mice, there have been lots of papers about targeting the HMGB1 within the contexts of infection, inflammation, and cancer. The pathogenic impact of HMGB1 to the severe acute respiratory syndrome (SARS) and disease management with herbal formulations targeting this unique protein have already been proposed. However, the failure of the numerous current anti-viral therapies on the ongoing viral infections casts reappraisal of the possible interrelationships regarding the HMGB1 and SARS-CoV-2. COVID-19 pandemic due to the SARS-CoV-2 virus is a currently ongoing challenging global health crisis. There is still not any proven exact treatment of COVID-19 with high level of evidence. In this paper, we focused on the potential usage of external and/or inhalation preparation of antiviral/antibacterial herbal products capable of targeting HMGB1 for the clinical management candidates of the ongoing COVID-19 infection.

Glycyrrhizin ameliorates melanoma cell extravasation into mouse lungs by regulating signal transduction through HMGB1 and its receptors

Metastasis, which accounts for the majority of all cancer-related deaths, occurs through several steps, namely, local invasion, intravasation, transport, extravasation, and colonization. Glycyrrhizin has been reported to inhibit pulmonary metastasis in mice inoculated with B16 melanoma. This study aimed to identify the mechanism through which glycyrrhizin ameliorates the extravasation of melanoma cells into mouse lungs. Following B16 melanoma cell injection, mice were orally administered glycyrrhizin once every two days over 2 weeks; lung samples were then obtained and analyzed. Blood samples were collected on the final day, and cytokine plasma levels were determined. We found that glycyrrhizin ameliorated the extravasation of melanoma cells into the lungs and suppressed the plasma levels of interleukin-6, tumor necrosis factor-α, and transforming growth factor-β. Furthermore, glycyrrhizin ameliorated the lung tissue expression of high mobility group box-1 protein (HMGB1), receptor for advanced glycation end products (RAGE), Toll-like receptor (TLR)-4, RAS, extracellular signal-related kinase, NF-κB, myeloid differentiation primary response 88, IκB kinase complex, epithelial-mesenchymal transition markers, and vascular endothelial growth factor-A. Our study demonstrates that glycyrrhizin ameliorates melanoma metastasis by regulating the HMGB1/RAGE and HMGB1/TLR-4 signal transduction pathways.

Long noncoding RNA MALAT1 sponges miR-129-5p to regulate the development of bronchopulmonary dysplasia by increasing the expression of HMGB1

OBJECTIVE

To explore the function and mechanism of long noncoding RNA (lncRNA) metastasis associated lung adenocarcinoma transcript 1 (MALAT1) in bronchopulmonary dysplasia.

METHODS

Alveolar epithelial cell line BEAS-2B was used as the cell model. The role of MALAT1 and microRNA miR-129-5p in regulating cellular viability and migration were examined by using the CCK-8 and Transwell assays, respectively, in vitro. The luciferase reporter assay and real-time (RT)-PCR were performed to confirm that miR-129-5p was a target of MALAT1. ELISA was conducted to validate MALAT1 and show that miR-129-5p regulated the gene encoding high-mobility group protein 1 (HMGB1).

RESULTS

Overexpression of MALAT1 significantly promoted cellular viability, whereas miR-129-5p had the opposite effect. miR-129-5p was shown to be a target of MALAT1, and HMGB1 could be upregulated by MALAT1 overexpression or miR-129-5p inhibition.

CONCLUSION

MALAT1 reduced the expression of miR-129-5p, promoting the viability of cells and blocking the development of bronchopulmonary dysplasia. In addition, MALAT1 increased the expression of HMGB1, which contributed to inflammation as the disease progressed.

The Potential Therapeutic Role of the HMGB1-TLR Pathway in Epilepsy

Epilepsy is one of the most common serious neurological disorders, affecting over 70 million people worldwide. For the treatment of epilepsy, antiepileptic drugs (AEDs) and surgeries are widely used. However, drug resistance and adverse effects indicate the need to develop targeted AEDs based on further exploration of the epileptogenic mechanism. Currently, many efforts have been made to elucidate the neuroinflammation theory in epileptogenesis, which may show potential in the treatment of epilepsy. In this respect, an important target protein, high mobility group box 1 (HMGB1), has received increased attention and has been developed rapidly. HMGB1 is expressed in various eukaryotic cells and localized in the cell nucleus. When HMGB1 is released by injuries or diseases, it participates in inflammation. Recent studies suggest that HMGB1 via Toll-like receptor (TLR) pathways can trigger inflammatory responses and play an important role in epilepsy. In addition, studies of HMGB1 have shown its potential in the treatment of epilepsy. Herein, the authors analyzed the experimental and clinical evidence of the HMGB1-TLR pathway in epilepsy to summarize the theory of epileptogenesis and provide insights into antiepileptic therapy in this novel field.

HΜGB1/sRAGE levels differ significantly between transudates and exudates

High mobility group box 1(HMGB1) protein operates as an alarmin with multiple roles in immunity and cell homeostasis. It is highly expressed in epithelial barrier sites and acts via the binding to the receptor for advanced glycation end products (RAGE). Production of HMGB1 and soluble RAGE (sRAGE), a decoy receptor for HMGB1, has been implicated in several pulmonary diseases, but both have been scarcely investigated in pleural diseases. The aim of this study was to determine the levels of HMGB1 and sRAGE in transudative, malignant and parapneumonic pleural effusions (PEs) and to investigate the effect of low and high HMGB1 pleural fluid levels on MeT-5A cell adhesion, migration and spheroid formation, in each group. HMGB1 and sRAGE levels were significantly lower and higher in transudative PEs compared to malignant and parapneumonic PEs, respectively. Patients above 65 years of age had significantly lower HMGB1 and higher sRAGE levels compared to patients below 65 years old. Furthermore, incubation of MeT-5A cells with malignant or parapneumonic PEs bearing low or high levels of HMGB1 yielded significant differential effects on MeT-5A cell adhesion, migration and spheroid formation. In all types of effusions, high HMGB1 levels correlated with more adherence compared to low HMGB1 levels. In transudative and malignant PEs high HMGB1 levels correlated with decreased migration of MeT-5A cells while in parapneumonic ones the effect was the opposite. Only samples from parapneumonic PEs high in HMGB1 achieved uniform spheroid formation. These results reveal a clinical context-dependent effect of the HMGB1/sRAGE axis in PEs.

Transcriptome of nasopharyngeal samples from COVID-19 patients and a comparative analysis with other SARS-CoV-2 infection models reveal disparate host responses against SARS-CoV-2

BACKGROUND

Although it is becoming evident that individual's immune system has a decisive influence on SARS-CoV-2 disease progression, pathogenesis is largely unknown. In this study, we aimed to profile the host transcriptome of COVID-19 patients from nasopharyngeal samples along with virus genomic features isolated from respective host, and a comparative analyses of differential host responses in various SARS-CoV-2 infection systems.

RESULTS

Unique and rare missense mutations in 3C-like protease observed in all of our reported isolates. Functional enrichment analyses exhibited that the host induced responses are mediated by innate immunity, interferon, and cytokine stimulation. Surprisingly, induction of apoptosis, phagosome, antigen presentation, hypoxia response was lacking within these patients. Upregulation of immune and cytokine signaling genes such as CCL4, TNFA, IL6, IL1A, CCL2, CXCL2, IFN, and CCR1 were observed in lungs. Lungs lacked the overexpression of ACE2 as suspected, however, high ACE2 but low DPP4 expression was observed in nasopharyngeal cells. Interestingly, directly or indirectly, viral proteins specially non-structural protein mediated overexpression of integrins such as ITGAV, ITGA6, ITGB7, ITGB3, ITGA2B, ITGA5, ITGA6, ITGA9, ITGA4, ITGAE, and ITGA8 in lungs compared to nasopharyngeal samples suggesting the possible way of enhanced invasion. Furthermore, we found comparatively highly expressed transcription factors such as CBP, CEBP, NFAT, ATF3, GATA6, HDAC2, TCF12 which have pivotal roles in lung injury.

CONCLUSIONS

Even though this study incorporates a limited number of cases, our data will provide valuable insights in developing potential studies to elucidate the differential host responses on the viral pathogenesis in COVID-19, and incorporation of further data will enrich the search of an effective therapeutics.

Regulation of the NLRP3 inflammasome with natural products against chemical-induced liver injury

The past decades have witnessed significant progress in understanding the process of sterile inflammation, which is dependent on a cytosolic complex termed the nucleotide-binding oligomerization domain (NOD)-like receptor containing pyrin domain 3 (NLRP3) inflammasome. Activation of NLRP3 inflammasome requires two steps, including the activation of Toll-like receptor (TLR) by its ligands, resulting in transcriptional procytokine and inflammasome component activation, and the assembly and activation of NLRP3 inflammasome triggered by various danger signals, leading to caspase-1 activation, which could subsequently cleave procytokines into their active forms. Metabolic disorders, ischemia and reperfusion, viral infection and chemical insults are common pathogenic factors of liver-related diseases that usually cause tissue damage and cell death, providing numerous danger signals for the activation of NLRP3 inflammasome. Currently, natural products have attracted much attention as potential agents for the prevention and treatment of liver diseases due to their multitargets and nontoxic natures. A great number of natural products have been shown to exhibit beneficial effects on liver injury induced by various chemicals through regulating NLRP3 inflammasome pathways. In this review, the roles of the NLRP3 inflammasome in chemical-induced liver injury (CILI) and natural products that exhibit beneficial effects in CILI through the regulation of inflammasomes were systematically summarized.

The pathophysiology of SARS-CoV-2: A suggested model and therapeutic approach

In this paper, a model is proposed of the pathophysiological processes of COVID-19 starting from the infection of human type II alveolar epithelial cells (pneumocytes) by SARS-CoV-2 and culminating in the development of ARDS. The innate immune response to infection of type II alveolar epithelial cells leads both to their death by apoptosis and pyroptosis and to alveolar macrophage activation. Activated macrophages secrete proinflammatory cytokines and chemokines and tend to polarise into the inflammatory M1 phenotype. These changes are associated with activation of vascular endothelial cells and thence the recruitment of highly toxic neutrophils and inflammatory activated platelets into the alveolar space. Activated vascular endothelial cells become a source of proinflammatory cytokines and reactive oxygen species (ROS) and contribute to the development of coagulopathy, systemic sepsis, a cytokine storm and ARDS. Pulmonary activated platelets are also an important source of proinflammatory cytokines and ROS, as well as exacerbating pulmonary neutrophil-mediated inflammatory responses and contributing to systemic sepsis by binding to neutrophils to form platelet-neutrophil complexes (PNCs). PNC formation increases neutrophil recruitment, activation priming and extraversion of these immune cells into inflamed pulmonary tissue, thereby contributing to ARDS. Sequestered PNCs cause the development of a procoagulant and proinflammatory environment. The contribution to ARDS of increased extracellular histone levels, circulating mitochondrial DNA, the chromatin protein HMGB1, decreased neutrophil apoptosis, impaired macrophage efferocytosis, the cytokine storm, the toll-like receptor radical cycle, pyroptosis, necroinflammation, lymphopenia and a high Th17 to regulatory T lymphocyte ratio are detailed.

The evaluation of hepatoprotective effects of flavonoids from Scorzonera austriaca Wild against CCl4-induced acute liver injury in vitro and in vivo

Scorzonera austriaca Wild is a traditional herbal medicine; however, little is known with regard to the effect of flavonoids from S. austriaca (FSA) on liver injury induced by Carbon tetrachloride (CCl₄), especially the mechanism remains unknown. Therefore, our paper was designed to investigate the hepatoprotective effect of FSA against CCl₄-induced acute liver injury in vitro and in vivo, with focus on its potential mechanism. The purity of FSA prepared by using polyporous resin column chromatography could reach 94.5%, and seven flavonoid compounds in FSA were identified by using LC-ESI-MS analysis. In vivo results showed that FSA markedly decreased the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and malonaldehyde (MDA) and increased the contents of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Furthermore, in vivo and in vitro results confirmed that FSA could inhibit inflammatory response, as evidenced by decreasing the levels of tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) through inactivating toll-like receptor-4/nuclear factor-κB (TLR4/NF-κB) signaling pathway. FSA activated autophagy by increasing the ratio of LC3B-II/I and decreasing the protein level of p62 so as to exert its hepatoprotective effect. In general, these evidences suggested that FSA is likely to serve as a potential material for the drugs against chemical hepatic injury.

Functionalisation of Fe3O4 nanoparticles by 2-((pyrazol-4-yl) methylene) hydrazinecarbothioamide enhances the apoptosis of human breast cancer MCF-7 cells

Cancer is a major cause of death. Thus, the incidence and mortality rate of cancer is globally important. Regarding vast problems caused by chemotherapy drugs, efforts have progressed to find new anti-cancer drugs. Pyrazole derivatives are known as components with anti-cancer properties. In here, Fe₃O₄ nanoparticles were first functionalized with (3-chloropropyl) trimethoxysilane, then 2-((pyrazol-4-yl) methylene) hydrazinecarbothioamide (P) was anchored on the surface of magnetic nanoparticles (PL). The synthesized nano-compounds were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, Zeta potential, dynamic light scattering, and energy-dispersive x-ray spectrometry analyses. The cytotoxicity effect was evaluated using MTT assay, apoptosis test by Flow cytometry, cell cycle analysis, Caspase-3 activity assay and Hoechst staining on MCF-7 cell line. The high toxicity for tumor cells and low toxicity on normal cells (MCF10A) was considered as an important feature (selectivity index, 10.9). Based on results, the IC50 for P and PL compounds were 157.80 and 131.84 μM/ml respectively. Moreover, apoptosis inducing, nuclear fragmentation, Caspase 3 activity and induction of cell rest in sub-G1 and S phases, were also observed. The inhibitory effect of PL was significantly higher than P, which could be due to the high penetrability of Fe₃O₄ nanoparticles.

Androgen and Androgen Receptors as Regulators of Monocyte and Macrophage Biology in the Healthy and Diseased Lung

Androgens, the predominant male sex hormones, drive the development and maintenance of male characteristics by binding to androgen receptor (AR). As androgens are systemically distributed throughout the whole organism, they affect many tissues and cell types in addition to those in male sexual organs. It is now clear that the immune system is a target of androgen action. In the lungs, many immune cells express ARs and are responsive to androgens. In this review, we describe the effects of androgens and ARs on lung myeloid immune cells-monocytes and macrophages-as they relate to health and disease. In particular, we highlight the effect of androgens on lung diseases, such as asthma, chronic obstructive pulmonary disease and lung fibrosis. We also discuss the therapeutic use of androgens and how circulating androgens correlate with lung disease. In addition to human studies, we also discuss how mouse models have helped to uncover the effect of androgens on monocytes and macrophages in lung disease. Although the role of estrogen and other female hormones has been broadly analyzed in the literature, we focus on the new perspectives of androgens as modulators of the immune system that target myeloid cells during lung inflammation.

MicroRNA-505-3p inhibits development of glioma by targeting HMGB1 and regulating AKT expression

Previous studies have reported that microRNA (miR)-505 exhibits important effect in human cancers. However, the regulatory mechanism of miR-505-3p/high-mobility group box 1 (HMGB1) axis is still unclear in glioma. Therefore, the regulatory mechanism of miR-505-3p/HMGB1 axis in glioma was illuminated. Expression of miR-505-3p and HMGB1 was observed by RT-qPCR. Protein expression was measured by western blot analysis. Dual luciferase assay was performed to confirm the relationship between miR-505-3p and HMGB1. The function of miR-505-3p was investigated by MTT and Transwell assays. Expression of miR-505-3p was reduced in glioma, which was related to poor clinical outcomes and prognosis in glioma patients. Moreover, overexpression of miR-505-3p suppressed proliferation, migration and invasion of glioma cells. In addition, HMGB1 was confirmed as a direct target of miR-505-3p, and miR-505-3p inhibited the development of glioma by targeting HMGB1. Furthermore, miR-505-3p blocked EMT suppressing p-AKT expression in glioma cells. In conclusion, miR-505-3p inhibited the development of glioma by targeting HMGB1 and regulating AKT expression.

An overview of high-mobility group box 1, a potent pro-inflammatory cytokine in asthma

High-mobility group box 1 (HMGB1), also called amphoterin, HMG1 and p30, is a highly conserved protein between different species that has various functions in nucleus such as stabilization of nucleosome formation, facilitation of deoxyribonucleic acid (DNA) bending and increasing the DNA transcription, replication and repair. It has also been indicated that HMGB1 acts as a potent pro-inflammatory cytokine with increasing concentrations in acute and chronic inflammatory diseases. Asthma is a common chronic respiratory disease associated with high morbidity and mortality rates. One central characteristic in its pathogenesis is airway inflammation. Considering the inflammatory role of HMGB1 and importance of inflammation in asthma pathogenesis, a better understanding of this protein is vital. This review describes the structure, cell surface receptors, signaling pathways and intracellular and extracellular functions of HMGB1, but also focuses on its inflammatory role in asthma. Moreover, this manuscript reviews experimental and clinical studies that investigated the pathologic role of HMGB1.

High-mobility group protein B1: A predictive biomarker for hepatic encephalopathy after transjugular intrahepatic portosystemic shunt

BACKGROUND

The aim of the present study was to investigate whether portal level of high-mobility group protein B1 (HMGB1) is associated with hepatic encephalopathy (HE) after transjugular intrahepatic portosystemic shunt (TIPS).

METHODS

We enrolled 127 consecutive patients who underwent TIPS and collected portal and peripheral blood samples in our department from December 2017 to May 2019. HMGB1 levels were determined using enzyme-linked immunosorbent assay kits. HMGB1 and other HE related parameters were estimated by competing risk analysis, receiver operating characteristic (ROC) analysis and Kaplan-Meier analysis.

RESULTS

Patients with HE after TIPS were older (P = .019) and had higher portal HMGB1 level (P = .038) than those without. Univariate competing risk analysis: age (sHR 1.025, P = .026), hepatorenal syndrome (sHR 3.149, P = .010), model for end-of-stage liver disease (MELD) score (sHR 1.055, P = .024), prior HE (sHR 4.029, P = .0005), portal HMGB1 before TIPS (sHR 1.177, P = .001) reached statistical significance. Multivariate analysis: age (sHR 1.025, P = .037), MELD score (sHR 1.062, P = .011), prior HE (sHR 2.492, P = .030) and portal HMGB1 level before TIPS (sHR 1.217, P = .0002) were significantly different. ROC analyses and Kaplan-Meier curve showed portal HMGB1 level changes before and after TIPS (ΔHMGB1) had good predictive value in the cut-off 0.012 ng/mL (AUC = 0.748, P < .001, Sensitivity = 0.743, Specificity = 0.655).

CONCLUSIONS

Portal HMGB1 may be a therapeutic target for post-TIPS HE.

Salvianic acid A alleviates chronic alcoholic liver disease by inhibiting HMGB1 translocation via down-regulating BRD4

Alcoholic liver disease (ALD) is the major cause of chronic liver disease and a global health concern. ALD pathogenesis is initiated with liver steatosis, and ALD can progress to steatohepatitis, fibrosis, cirrhosis and even hepatocellular carcinoma. Salvianic acid A (SAA) is a phenolic acid component of Danshen, a Chinese herbal medicine with possible hepatoprotective properties. The purpose of this study was to investigate the effect of SAA on chronic alcoholic liver injury and its molecular mechanism. We found that SAA significantly inhibited alcohol‐induced liver injury and ameliorated ethanol‐induced hepatic inflammation. These protective effects of SAA were likely carried out through its suppression of the BRD4/HMGB1 signalling pathway, because SAA treatment largely diminished alcohol‐induced BRD4 expression and HMGB1 nuclear translocation and release. Importantly, BRD4 knockdown prevented ethanol‐induced HMGB1 release and inflammatory cytokine production in AML‐12 cells. Similarly, alcohol‐induced pro‐inflammatory cytokines were blocked by HMGB1 siRNA. Collectively, our results reveal that activation of the BRD4/HMGB1 pathway is involved in ALD pathogenesis. Therefore, manipulation of the BRD4/HMGB1 pathway through strategies such as SAA treatment holds great therapeutic potential for chronic alcoholic liver disease therapy.

Severe COVID-19: NLRP3 Inflammasome Dysregulated

SARS-CoV-2 might directly activate NLRP3 inflammasome resulting in an endogenous adjuvant activity necessary to mount a proper adaptive immune response against the virus. Heterogeneous response of COVID-19 patients could be attributed to differences in not being able to properly downregulate NLRP3 inflammasome activation. This relates to the fitness of the immune system of the individual challenged by the virus. Patients with a reduced immune fitness can demonstrate a dysregulated NLRP3 inflammasome activity resulting in severe COVID-19 with tissue damage and a cytokine storm. We sketch the outlines of five possible scenarios for COVID-19 in medical practice and provide potential treatment options targeting dysregulated endogenous adjuvant activity in severe COVID-19 patients.

Glycyrrhizin suppresses epithelial-mesenchymal transition by inhibiting high-mobility group box1 via the TGF-β1/Smad2/3 pathway in lung epithelial cells

Background

Epithelial-mesenchymal transition (EMT) plays an important role in fibrosis, chronic inflammation, tumor metastasis, etc. Glycyrrhizin, an active component extracted from licorice plant, has been reported to treat a variety of inflammatory reactions through inhibiting high-mobility group box1 (HMGB1), which has been suggested to be a significant mediator in EMT process. However, whether glycyrrhizin affects the EMT process or not remains unclear.

Methods

Human alveolar epithelial cell line A549 and normal human bronchial epithelial cell line BEAS-2B were treated with extrinsic TGF-β1 to induce EMT. Elisa was used to detect HMGB1 concentrations in cell supernatant. RNA interference and lentivirus infection experiments were performed to investigate the involvement of HMGB1 in EMT process. Cell Counting Kit-8 (CCK-8) was used to detect the viability of A549 and BEAS-2B cells treated with glycyrrhizin. Finally, the effects of glycyrrhizin on EMT changes, as well as the underlying mechanisms, were evaluated via Western blot, immunofluorescence and transwell assays.

Results

Our results showed that HMGB1 expression was increased by TGF-β1, and knockdown of HMGB1 expression reversed TGF-β1-induced EMT in A549 and BEAS-2B cells. Ectopic HMGB1 expression or TGF-β1 treatment caused a significant increase in HMGB1 release. Notably, we found that glycyrrhizin treatment effectively suppressed TGF-β1-induced EMT process by inhibiting HMGB1. Also, glycyrrhizin significantly inhibited the migration of both A549 and BEAS-2B cells promoted by TGF-β1. Mechanistically, HMGB1 overexpression could activate Smad2/3 signaling in A549 and BEAS-2B cells. Glycyrrhizin significantly blocked the phosphorylation of Smad2/3 stimulated either by TGF-β1 or by ectopic HMGB1 in A549 and BEAS-2B cells.

Conclusions

HMGB1 is a vital mediator of EMT changes induced by TGF-β1 in lung epithelial cells. Importantly, glycyrrhizin can effectively block Smad2/3 signaling pathway through inhibiting HMGB1, thereby suppressing the EMT progress.

Cigarette smoke-induced HMGB1 translocation and release contribute to migration and NF-κB activation through inducing autophagy in lung macrophages

High-mobility group box 1 (HMGB1) shows pro-inflammatory activity in various inflammatory diseases and has been found up-regulated in chronic obstructive pulmonary disease (COPD). Lung macrophages play an important role in airway inflammation and lung destruction in COPD, yet whether HMGB1 is involved in cigarette smoke (CS)-induced lung macrophage dysfunction is unknown. We sought to evaluate the intracellular localization and release of HMGB1 in lung macrophages from COPD patients and CS-exposed mice, and to investigate the role of HMGB1 in regulating autophagy in CS extract (CSE)-treated lung macrophages (MH-S cells). Our results showed that HMGB1 was highly expressed in lung tissues and sera of COPD patients and CS-exposed mice, along with predominantly cytoplasmic exporting from nuclei in lung macrophages. In vitro experiments revealed that CSE promoted the expression, nucleocytoplasmic translocation and release of HMGB1 partly via the nicotinic acetylcholine receptor (nAChR). Blockade of HMGB1 with chicken anti-HMGB1 polyclonal antibody (anti-HMGB1) or glycyrrhizin (Gly) attenuated the increase of LC3B-II and Beclin1, migration and p65 phosphorylation, suggesting the involvement of HMGB1 in autophagy, migration and NF-κB activation of lung macrophages. Hydroxychloroquine (CQ), an autophagy inhibitor, enhanced the increase of LC3B-II but not Beclin1 in CSE or rHMGB1-treated MH-S cells, and inhibition of autophagy by CQ and 3-methyladenine (3-MA) abrogated the migration and p65 phosphorylation of CSE-treated cells. These results indicate that CS-induced HMGB1 translocation and release contribute to migration and NF-κB activation through inducing autophagy in lung macrophages, providing novel evidence for HMGB1 as a potential target of intervention in COPD.

Neural-respiratory inflammasome axis in traumatic brain injury

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality. Approximately 20-25% of TBI subjects develop Acute Lung Injury (ALI), but the pathomechanisms of TBI-induced ALI remain poorly defined. Currently, mechanical ventilation is the only therapeutic intervention for TBI-induced lung injury. Our recent studies have shown that the inflammasome plays an important role in the systemic inflammatory response leading to lung injury-post TBI. Here, we outline the role of the extracellular vesicle (EV)-mediated inflammasome signaling in the etiology of TBI-induced ALI. Furthermore, we evaluate the efficacy of a low molecular weight heparin (Enoxaparin, a blocker of EV uptake) and a monoclonal antibody against apoptosis speck-like staining protein containing a caspase recruitment domain (anti-ASC) as therapeutics for TBI-induced lung injury. We demonstate that activation of an EV-mediated Neural-Respiratory Inflammasome Axis plays an essential role in TBI-induced lung injury and disruption of this axis has therapeutic potential as a treatment strategy.

High mobility group box-1 release from H2O2-injured hepatocytes due to sirt1 functional inhibition

BACKGROUND

High mobility group box-1 (HMGB1), recognized as a representative of damage-associated molecular patterns, is released during cell injury/death, triggering the inflammatory response and ultimately resulting in tissue damage. Dozens of studies have shown that HMGB1 is involved in certain diseases, but the details on how injured hepatocytes release HMGB1 need to be elicited.

AIM

To reveal HMGB1 release mechanism in hepatocytes undergoing oxidative stress.

METHODS

C57BL6/J male mice were fed a high-fat diet for 12 wk plus a single binge of ethanol to induce severe steatohepatitis. Hepatocytes treated with H₂O₂ were used to establish an in vitro model. Serum alanine aminotransferase, liver H₂O₂ content and catalase activity, lactate dehydrogenase and 8-hydroxy-2-deoxyguanosine content, nicotinamide adenine dinucleotide (NAD⁺) levels, and Sirtuin 1 (Sirt1) activity were detected by spectrophotometry. HMGB1 release was measured by enzyme linked immunosorbent assay. HMGB1 translocation was observed by immunohistochemistry/immunofluorescence or Western blot. Relative mRNA levels were assayed by qPCR and protein expression was detected by Western blot. Acetylated HMGB1 and poly(ADP-ribose)polymerase 1 (Parp1) were analyzed by Immunoprecipitation.

RESULTS

When hepatocytes were damaged, HMGB1 translocated from the nucleus to the cytoplasm because of its hyperacetylation and was passively released outside both in vivo and in vitro. After treatment with Sirt1-siRNA or Sirt1 inhibitor (EX527), the hyperacetylated HMGB1 in hepatocytes increased, and Sirt1 activity inhibited by H₂O₂ could be reversed by Parp1 inhibitor (DIQ). Parp1 and Sirt1 are two NAD⁺-dependent enzymes which play major roles in the decision of a cell to live or die in the context of stress . We showed that NAD⁺ depletion attributed to Parp1 activation after DNA damage was caused by oxidative stress in hepatocytes and resulted in Sirt1 activity inhibition. On the contrary, Sirt1 suppressed Parp1 by negatively regulating its gene expression and deacetylation.

CONCLUSION

The functional inhibition between Parp1 and Sirt1 leads to HMGB1 hyperacetylation, which leads to its translocation from the nucleus to the cytoplasm and finally outside the cell.