HMGB1-induced asthmatic airway inflammation through GRP75-mediated enhancement of ER-mitochondrial Ca2+ transfer and ROS increased

Induction of Ca2+ signaling and cytotoxic responses of human lung fibroblasts upon an antihistamine drug oxatomide treatment and evaluating the protective effects of Ca2+ chelating

BACKGROUND

Oxatomide, an antihistamine drug of the diphenylmethylpiperazine family, has anti-inflammatory effects in airway disease. Because oxatomide was shown to cause diverse physiological responses in several cell models, the impact of oxatomide on Ca2+ signaling and its related physiological effects has not been explored in IMR-90 human fetal lung fibroblasts.

OBJECTIVES

This study assessed the effect of oxatomide on cell viability and intracellular free Ca2+ concentrations ([Ca2+]i) and examined whether oxatomide-induced cytotoxicity through Ca2+ signaling in IMR-90 cells.

METHODS

Cell viability was measured by the cell proliferation reagent (WST-1). [Ca2+]i was measured by the Ca2+-sensitive fluorescent dye fura-2.

RESULTS

Oxatomide (10-40 μM) concentration dependently reduced cell viability and induced [Ca2+]i rises in IMR-90 cells. This cytotoxic effect was reversed by chelation of cytosolic Ca2+ with BAPTA-AM. In terms of Ca2+ signaling, oxatomide-caused Ca2+ entry was inhibited by modulators of store-operated Ca2+ channels (2-APB and SKF96365) and protein kinase C (PKC) inhibitor (GF109203X). Furthermore, oxatomide-induced Ca2+ influx was confirmed by Mn2+-induced quench of fura-2 fluorescence. In a Ca2+-free medium, preincubation with the endoplasmic reticulum Ca2+ pump inhibitor thapsigargin inhibited oxatomide-evoked [Ca2+]i rises. Conversely, treatment with oxatomide abolished thapsigargin-induced [Ca2+]i rises. Inhibition of phospholipase C (PLC) with U73122 also inhibited oxatomide-caused [Ca2+]i rises.

CONCLUSION

In IMR-90 cells, oxatomide-induced cytotoxicity by preceding [Ca2+]i rises involving PKC-sensitive store-operated Ca2+ entry and PLC-dependent Ca2+ release from the endoplasmic reticulum. BAPTA-AM, with its Ca2+ chelating effects, may be a potential compound for preventing oxatomide-induced cytotoxicity.

Mechanism of miR-130b-3p in relieving airway inflammation in asthma through HMGB1-TLR4-DRP1 axis

Asthma is a chronic inflammatory respiratory disease characterized by recurrent breathing difficulties caused by airway obstruction and hypersensitivity. Although there is diversity in their specific mechanisms, microRNAs (miRNAs) have a significant impact on the development of asthma. Currently, the contribution of miR-130b-3p to asthma remains elusive. The goal of this study was to examine whether miR-130b-3p attenuates house dust mite (HDM)-induced asthma through High-mobility group box protein 1 (HMGB1)/Toll-like receptor 4 (TLR4)/mitochondrial fission protein (DRP1) signaling pathway. We elucidate that miR-130b-3p can bind to the HMGB1 3'UTR, attenuating HMGB1 mRNA and protein levels, and nucleo-cytoplasmic translocation of HMGB1. We observed that miR-130b-3p agomir or HMGB1 CKO attenuated HDM-induced airway inflammation and hyperresponsiveness, and decreased Th2-type cytokines in bronchoalveolar lavage fluid (BALF) and mediastinal lymph nodes. Further, HMGB1 CKO contributes to alleviating Th2 inflammation in AT-II cells (CD45.2-/CD31-/Epcam-+/proSP-C+/MHC-II+) from lung single cell suspensions of asthmatic mice by flow cytometry. Our findings identified miR-130b-3p as a potent regulator in asthma that exerts its anti-inflammatory effects by targeting HMGB1 and the subsequent HMGB1/TLR4/DRP1axis, presenting a prospective novel therapeutic avenue for asthma management.

The role of HMGB1 on SiC NPs-induced inflammation response in lung epithelial-macrophage co-culture system

In recent years, carbonized silicon nanoparticles (SiC NPs) have found widespread scientific and engineering applications, raising concerns about potential human health risks. SiC NPs may induce pulmonary damage through sustained inflammatory responses and oxidative stress, with unclear toxicity mechanisms. This study uses an in vitro co-culture model of alveolar macrophages (NR8383) and alveolar epithelial cells (RLE-6TN) to simulate the interaction between airway epithelial cells and immune cells, providing initial insights into SiC NP-triggered inflammatory responses. The research reveals that increasing SiC NP exposure prompts NR8383 cells to release high mobility group box 1 protein (HMGB1), which migrates into RLE-6TN cells and activates the receptor for advanced glycation end-products (RAGE) and Toll-like receptor 4 (TLR4). RAGE and TLR4 synergistically activate the MyD88/NF-κB inflammatory pathway, ultimately inducing inflammatory responses and oxidative stress in RLE-6TN cells, characterized by excessive ROS generation and altered cytokine levels. Pretreatment with RAGE and TLR4 inhibitors attenuates SiC-induced HMGB1 expression and downstream pathway proteins, reducing inflammatory responses and oxidative damage. This highlights the pivotal role of RAGE-TLR4 crosstalk in SiC NP-induced pulmonary inflammation, providing insights into SiC NP cytotoxicity and nanomaterial safety guidelines.

Revisiting airway epithelial dysfunction and mechanisms in chronic obstructive pulmonary disease: the role of mitochondrial damage

Chronic exposure to environmental hazards causes airway epithelial dysfunction, primarily impaired physical barriers, immune dysfunction, and repair or regeneration. Impairment of airway epithelial function subsequently leads to exaggerated airway inflammation and remodeling, the main features of chronic obstructive pulmonary disease (COPD). Mitochondrial damage has been identified as one of the mechanisms of airway abnormalities in COPD, which is closely related to airway inflammation and airflow limitation. In this review, we evaluate updated evidence for airway epithelial mitochondrial damage in COPD and focus on the role of mitochondrial damage in airway epithelial dysfunction. In addition, the possible mechanism of airway epithelial dysfunction mediated by mitochondrial damage is discussed in detail, and recent strategies related to airway epithelial-targeted mitochondrial therapy are summarized. Results have shown that dysregulation of mitochondrial quality and oxidative stress may lead to airway epithelial dysfunction in COPD. This may result from mitochondrial damage as a central organelle mediating abnormalities in cellular metabolism. Mitochondrial damage mediates procellular senescence effects due to mitochondrial reactive oxygen species, which effectively exacerbate different types of programmed cell death, participate in lipid metabolism abnormalities, and ultimately promote airway epithelial dysfunction and trigger COPD airway abnormalities. These can be prevented by targeting mitochondrial damage factors and mitochondrial transfer. Thus, because mitochondrial damage is involved in COPD progression as a central factor of homeostatic imbalance in airway epithelial cells, it may be a novel target for therapeutic intervention to restore airway epithelial integrity and function in COPD.

Identification and validation of aging-related genes in atrial fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in the clinic. Aging plays an essential role in the occurrence and development of AF. Herein, we aimed to identify the aging-related genes associated with AF using bioinformatics analysis. Transcriptome profiles of AF were obtained from the GEO database. Differential expression analysis was performed to identify AF-specific aging-related genes. GO and KEGG enrichment analyses were performed. Subsequently, the LASSO, SVM-RFE, and MCC algorithms were applied to screen aging-related genes. The mRNA expression of the screened genes was validated in the left atrial samples of aged rapid atrial pacing-induced AF canine models and their counterparts. The ROC curves of them were drawn to evaluate their diagnostic potential. Moreover, CIBERSORT was used to estimate immune infiltration. A correlation analysis between screened aging-related genes and infiltrating immune cells was performed. A total of 24 aging-related genes were identified, which were found to be mainly involved in the FoxO signaling pathway, PI3K-Akt signaling pathway, longevity regulating pathway, and peroxisome according to functional enrichment analysis. LASSO, SVM-RFE, and MCC algorithms identified three genes (HSPA9, SOD2, TXN). Furthermore, the expression levels of HSPA9 and SOD2 were validated in aged rapid atrial pacing-induced AF canine models. HSPA9 and SOD2 could be potential diagnostic biomarkers for AF, as evidenced by the ROC curves. Immune infiltration and correlation analysis revealed that HSPA9 and SOD2 were related to immune cell infiltrates. Collectively, these findings provide novel insights into the potential aging-related genes associated with AF. HSPA9 and SOD2 may play a significant role in the occurrence and development of AF.

Hypermethylation of RNF125 promotes autophagy-induced oxidative stress in asthma by increasing HMGB1 stability

Asthma is a global chronic airway disease. The expression and role of RNF125, an E3 ubiquitin ligase, in asthma remain uncertain. In this study, we revealed that RNF125 was downregulated in the bronchial epithelium of mice and patients with asthma. Rnf125 hypermethylation was responsible for the low expression of RNF125 in primary airway epithelial cells of mice treated with OVA. Moreover, we demonstrated that RNF125 could attenuate autophagy, oxidative stress, and protect epithelial barrier in vivo and in vitro. Additionally, we identified HMGB1 as a substrate of RNF125, which interacted with the HMG B-box domain of HMGB1 and induced degradation via the ubiquitin proteasome system, reducing autophagy and oxidative stress. Overall, our findings elucidated that hypermethylation of Rnf125 reduced its expression, which promoted autophagy-induced oxidative stress in asthma by increasing HMGB1 stability. These findings offer a theoretical and experimental basis for the pathogenesis of asthma.

The ER-mitochondria interface, where Ca2+ and cell death meet

Endoplasmic reticulum (ER)-mitochondria contact sites are crucial to allow Ca²⁺ flux between them and a plethora of proteins participate in tethering both organelles together. Inositol 1,4,5-trisphosphate receptors (IP₃Rs) play a pivotal role at such contact sites, participating in both ER-mitochondria tethering and as Ca²⁺-transport system that delivers Ca²⁺ from the ER towards mitochondria. At the ER-mitochondria contact sites, the IP₃Rs function as a multi-protein complex linked to the voltage-dependent anion channel 1 (VDAC1) in the outer mitochondrial membrane, via the chaperone glucose-regulated protein 75 (GRP75). This IP₃R-GRP75-VDAC1 complex supports the efficient transfer of Ca²⁺ from the ER into the mitochondrial intermembrane space, from which the Ca²⁺ ions can reach the mitochondrial matrix through the mitochondrial calcium uniporter. Under physiological conditions, basal Ca²⁺ oscillations deliver Ca²⁺ to the mitochondrial matrix, thereby stimulating mitochondrial oxidative metabolism. However, when mitochondrial Ca²⁺ overload occurs, the increase in [Ca²⁺] will induce the opening of the mitochondrial permeability transition pore, thereby provoking cell death. The IP₃R-GRP75-VDAC1 complex forms a hub for several other proteins that stabilize the complex and/or regulate the complex's ability to channel Ca²⁺ into the mitochondria. These proteins and their mechanisms of action are discussed in the present review with special attention for their role in pathological conditions and potential implication for therapeutic strategies.

USP13 regulates HMGB1 stability and secretion through its deubiquitinase activity

BACKGROUND

High mobility group box 1 (HMGB1) is a damage-associated molecular pattern (DAMP) molecule that plays a central role in innate immunity. HMGB1 acts as a late mediator of inflammation when actively secreted in response to inflammatory stimuli. Several post-translational modifications (PTMs), including acetylation, phosphorylation, and oxidation, are involved in HMGB1 secretion. However, the E3 ligases of HMGB1 and the mechanism by which DUBs regulate HMGB1 deubiquitination are not well known.

METHODS

LC-MS/MS, proximity ligation assay, immunoprecipitation were used to identify ubiquitin-specific protease 13 (USP13) as a binding partner of HMGB1 and to investigate ubiquitination of HMGB1. USP13 domain mutant was constructed for domain study and Spautin-1 was treated for inhibition of USP13. Confocal microscopy image showed localization of HMGB1 by USP13 overexpression. The data were analyzed using one-way analysis of variance with Tukey's honestly significant difference post-hoc test for multiple comparisons or a two-tailed Student's t-test.

RESULTS

We identified ubiquitin-specific protease 13 (USP13) as a novel binding partner of HMGB1 and demonstrated that USP13 plays a role in stabilizing HMGB1 from ubiquitin-mediated degradation. USP13 overexpression increased nucleocytoplasmic translocation of HMGB1 and promoted its secretion, which was inhibited by treatment with Spautin-1, a selective inhibitor of USP13.

CONCLUSION

Taken together, we suggest that USP13 is a novel deubiquitinase of HMGB1 that regulates the stability and secretion of HMGB1.

Salidroside Ameliorates Ischemia-Induced Neuronal Injury through AMPK Dependent and Independent Pathways to Maintain Mitochondrial Quality Control

Salidroside, an active ingredient in Rhodiola rosea, has potent protective activity against cerebral ischemia. However, the mechanisms underlying its pharmacological actions are poorly understood. In this study, we employed a mouse middle cerebral artery occlusion (MCAO) and cellular oxygen and glucose deprivation (OGD) models to test the hypothesis that salidroside may restore mitochondrial quality control in neurons by modulating the relevant signaling. The results indicated that salidroside mitigated almost 40% the ischemia-induced brain infarct volumes in mice and the OGD-decreased viability of neurons to ameliorate the mitochondrial functions. Furthermore, salidroside treatment alleviated the OGD- or ischemia-induced imbalance of mitochondrial fission and fusion, mitophagy and promoted mitochondrial biogenesis in neurons by attenuating the AMPK activity. Moreover, salidroside alleviated 50% the OGD-promoted mitochondrial calcium fluorescence intensity and 5% mitochondria-associated membrane (MAM) area by down-regulating GRP75 expression independent of the AMPK signaling. Finally, similar findings were achieved in primary mouse neurons. Collectively, these data indicate that salidroside effectively restores the mitochondria dynamics, facilitates mitochondrial biogenesis by attenuating the AMPK signaling, and maintains calcium homeostasis in neurons independent of the AMPK activity.

IP3R1/GRP75/VDAC1 complex mediates endoplasmic reticulum stress-mitochondrial oxidative stress in diabetic atrial remodeling

RATIONALE

Endoplasmic reticulum (ER) stress and mitochondrial dysfunction are important mechanisms of atrial remodeling, predisposing to the development of atrial fibrillation (AF) in type 2 diabetes mellitus (T2DM). However, the molecular mechanisms underlying these processes especially their interactions have not been fully elucidated.

OBJECTIVE

To explore the potential role of ER stress-mitochondrial oxidative stress in atrial remodeling and AF induction in diabetes.

METHODS AND RESULTS

Mouse atrial cardiomyocytes (HL-1 cells) and rats with T2DM were used as study models. Significant ER stress was observed in the diabetic rat atria. After treatment with tunicamycin (TM), an ER stress agonist, mass spectrometry (MS) identified several known ER stress and calmodulin proteins, including heat shock protein family A (HSP70) member [HSPA] 5 [GRP78]) and HSPA9 (GRP75, glucose-regulated protein 75). In situ proximity ligation assay indicated that TM led to increased protein expression of the IP3R1-GRP75-VDAC1 (inositol 1,4,5-trisphosphate receptor 1-glucose-regulated protein 75-voltage-dependent anion channel 1) complex in HL-1 cells. Small interfering RNA silencing of GRP75 in HL-1 cells and GRP75 conditional knockout in a mouse model led to impaired calcium transport from the ER to the mitochondria and alleviated mitochondrial oxidative stress and calcium overload. Moreover, GRP75 deficiency attenuated atrial remodeling and AF progression in Myh6-Cre+/Hspa9flox/flox + TM mice.

CONCLUSIONS

The IP3R1-GRP75-VDAC1 complex mediates ER stress-mitochondrial oxidative stress and plays an important role in diabetic atrial remodeling.

GRP75 Regulates Mitochondrial-Supercomplex Turnover to Modulate Insulin Sensitivity

GRP75 (75-kDA glucose-regulated protein), defined as a major component of both the mitochondrial quality control system and mitochondria-associated membrane, plays a key role in mitochondrial homeostasis. In this study, we assessed the roles of GRP75, other than as a component, in insulin action in both in vitro and in vivo models with insulin resistance. We found that GRP75 was downregulated in mice fed a high-fat diet (HFD) and that induction of Grp75 in mice could prevent HFD-induced obesity and insulin resistance. Mechanistically, GRP75 influenced insulin sensitivity by regulating mitochondrial function through its modulation of mitochondrial-supercomplex turnover rather than mitochondria-associated membrane communication: GRP75 was negatively associated with respiratory chain complex activity and was essential for mitochondrial-supercomplex assembly and stabilization. Moreover, mitochondrial dysfunction in Grp75-knockdown cells might further increase mitochondrial fragmentation, thus triggering cytosolic mtDNA release and activating the cGAS/STING-dependent proinflammatory response. Therefore, GRP75 can serve as a potential therapeutic target of insulin resistant-related diabetes or other metabolic diseases.

α-Synuclein Interactions in Mitochondria-ER Contacts: A Possible Role in Parkinson's Disease

Endoplasmic reticulum-mitochondria contact sites regulate various biological processes, such as mitochondrial dynamics, calcium homeostasis, autophagy and lipid metabolism. Notably, dysfunctions in these contact sites are closely related to neurodegenerative diseases, including Parkinson's disease, Alzheimer's disease and amyotrophic lateral sclerosis. However, details about the role of endoplasmic reticulum-mitochondria contact sites in neurodegenerative diseases remain unknown. In Parkinson's disease, interactions between α-synuclein in the contact sites and components of tether complexes that connect organelles can lead to various dysfunctions, especially with regards to calcium homeostasis. This review will summarize the main tether complexes present in endoplasmic reticulum-mitochondria contact sites, and their roles in calcium homeostasis and trafficking. We will discuss the impact of α-synuclein accumulation, its interaction with tethering complex components and the implications in Parkinson's disease pathology.

GRP75 mediates endoplasmic reticulum-mitochondria coupling during palmitate-induced pancreatic β-cell apoptosis

The endoplasmic reticulum (ER) and mitochondria are structurally connected with each other at specific sites termed mitochondria-associated membranes (MAMs). These physical links are composed of several tethering proteins and are important during varied cellular processes, such as calcium homeostasis, lipid metabolism and transport, membrane biogenesis, and organelle remodeling. However, the attributes of specific tethering proteins in these cellular functions remain debatable. Here, we present data to show that one such tether protein, glucose regulated protein 75 (GRP75), is essential in increasing ER-mitochondria contact during palmitate-induced apoptosis in pancreatic insulinoma cells. We demonstrate that palmitate increased GRP75 levels in mouse and rat pancreatic insulinoma cells as well as in mouse primary islet cells. This was associated with increased mitochondrial Ca2+ transfer, impaired mitochondrial membrane potential, increased ROS production, and enhanced physical coupling between the ER and mitochondria. Interestingly, GRP75 inhibition prevented these palmitate-induced cellular aberrations. Additionally, GRP75 overexpression alone was sufficient to impair mitochondrial membrane potential, increase mitochondrial Ca2+ levels and ROS generation, augment ER-mitochondria contact, and induce apoptosis in these cells. In vivo injection of palmitate induced hyperglycemia and hypertriglyceridemia, as well as impaired glucose and insulin tolerance in mice. These animals also exhibited elevated GRP75 levels accompanied by enhanced apoptosis within the pancreatic islets. Our findings suggest that GRP75 is critical in mediating palmitate-induced ER-mitochondrial interaction leading to apoptosis in pancreatic islet cells.

Molecular mechanisms of oxidative stress in asthma

The lungs are exposed to reactive oxygen species oxygen (ROS) produced as a result of inhalation of oxygen, as well as smoke and other air pollutants. Cell metabolism and the NADPH oxidases (Nox) generate low levels of intracellular ROS that act as signal transduction mediators by inducing oxidative modifications of histones, enzymes and transcription factors. Redox signalling is also regulated by localised production and sensing of ROS in mitochondria, the endoplasmic reticulum (ER) and inside the nucleus. Intracellular ROS are maintained at low levels through the action of a battery of enzymatic and non-enzymatic antioxidants. Asthma is a heterogeneous airway inflammatory disease with different immune endotypes; these include atopic or non-atopic Th2 type immune response associated with eosinophilia, or a non-Th2 response associated with neutrophilia. Airway remodelling and hyperresponsiveness accompany the inflammatory response in asthma. Over-production of ROS resulting from infiltrating immune cells, particularly eosinophils and neutrophils, and a concomitant impairment of antioxidant responses lead to development of oxidative stress in asthma. Oxidative stress is augmented in severe asthma and during exacerbations, as well as by air pollution and obesity, and causes oxidative damage of tissues promoting airway inflammation and hyperresponsiveness. Furthermore, deregulated Nox activity, mitochondrial dysfunction, ER stress and/or oxidative DNA damage, resulting from exposure to irritants, inflammatory mediators or obesity, may lead to redox-dependent changes in cell signalling. ROS play a central role in airway epithelium-mediated sensing, development of innate and adaptive immune responses, and airway remodelling and hyperresponsiveness. Nonetheless, antioxidant compounds have proven clinically ineffective as therapeutic agents for asthma, partly due to issues with stability and in vivo metabolism of these compounds. The compartmentalised nature of ROS production and sensing, and the role of ROS in homeostatic responses and in the action of corticosteroids and β2-adrenergic receptor agonists, adds another layer of complexity to antioxidant therapy development. Nox inhibitors and mitochondrial-targeted antioxidants are in clinical development for a number of diseases but they have not yet been investigated in asthma. A better understanding of the complex role of ROS in the pathogenesis of asthma will highlight new opportunities for more targeted and effective redox therapies.

Oxidative Stress Promotes Corticosteroid Insensitivity in Asthma and COPD

Corticosteroid insensitivity is a key characteristic of patients with severe asthma and COPD. These individuals experience greater pulmonary oxidative stress and inflammation, which contribute to diminished lung function and frequent exacerbations despite the often and prolonged use of systemic, high dose corticosteroids. Reactive oxygen and nitrogen species (RONS) promote corticosteroid insensitivity by disrupting glucocorticoid receptor (GR) signaling, leading to the sustained activation of pro-inflammatory pathways in immune and airway structural cells. Studies in asthma and COPD models suggest that corticosteroids need a balanced redox environment to be effective and to reduce airway inflammation. In this review, we discuss how oxidative stress contributes to corticosteroid insensitivity and the importance of optimizing endogenous antioxidant responses to enhance corticosteroid sensitivity. Future studies should aim to identify how antioxidant-based therapies can complement corticosteroids to reduce the need for prolonged high dose regimens in patients with severe asthma and COPD.

High-Throughput Screen Detects Calcium Signaling Dysfunction in Hutchinson-Gilford Progeria Syndrome

Hutchinson-Gilford progeria syndrome (HGPS) is a deadly childhood disorder, which is considered a very rare disease. It is caused by an autosomal dominant mutation on the LMNA gene, and it is characterized by accelerated aging. Human cell lines from HGPS patients and healthy parental controls were studied in parallel using next-generation sequencing (NGS) to unravel new non-previously altered molecular pathways. Nine hundred and eleven transcripts were differentially expressed when comparing healthy versus HGPS cell lines from a total of 21,872 transcripts; ITPR1, ITPR3, CACNA2D1, and CAMK2N1 stood out among them due to their links with calcium signaling, and these were validated by Western blot analysis. It was observed that the basal concentration of intracellular Ca2+ was statistically higher in HGPS cell lines compared to healthy ones. The relationship between genes involved in Ca2+ signaling and mitochondria-associated membranes (MAM) was demonstrated through cytosolic calcium handling by means of an automated fluorescent plate reading system (FlexStation 3, Molecular Devices), and apoptosis and mitochondrial ROS production were examined by means of flow cytometry analysis. Altogether, our data suggest that the Ca2+ signaling pathway is altered in HGPS at least in part due to the overproduction of reactive oxygen species (ROS). Our results unravel a new therapeutic window for the treatment of this rare disease and open new strategies to study pathologies involving both accelerated and healthy aging.

The role of HMGB1 on TDI-induced NLPR3 inflammasome activation via ROS/NF-κB pathway in HBE cells

To explore the potential role of HMGB1 on TDI-induced NLRP3 inflammasome activation, HBE cells were treated with TDI-HSA conjugate to observe the changes of HMGB1, TLR4, NF-κB, Nrf2 and NLRP3 inflammasome related proteins expressions, ROS release and MMP. NAC, TPCA-1 and Resatorvid pre-treatments were applied to explore the effects of ROS, NF-κB and TLR4 on TDI-induced NLRP3 inflammasome activation. The CRISPR/Cas9 system was used to construct HMGB1 gene knockout HBE cell line and then to explore the role of HMGB1 on TDI-HSA induced NLRP3 inflammasome activation. GL pre-treatment was applied to further confirm the role of HMGB1. Results showed that TDI increased HMGB1, TLR4, P-p65, Nrf2 proteins expressions and ROS release, decreased MMP level and activated NLRP3 inflammasome in HBE cells in a dose dependent manner. NAC, TPCA-1 and Resatorvid pre-treatments decreased the expression of P-p65 and inhibited NLRP3 inflammasome activation. Inhibition of HMGB1 decreased Nrf2 expression and ROS release, improved MMP level and reduced NLRP3 inflammasome activation. GL ameliorated NLRP3 inflammasome activation via inhibiting HMGB1 regulated ROS/NF-κB pathway. These results indicated that HMGB1 was involved in TDI-induced NLRP3 inflammasome activation as a positive regulatory mechanism. The study provided a potential target for early prevention and treatment of TDI-OA.

Serum level of high mobility group box protein-1 and prognosis of patients with end-stage renal disease on hemodialysis and peritoneal dialysis

To investigate serum level of high mobility group box protein-1 (HMGB1) and prognosis of patients with end-stage renal disease (ESRD) on hemodialysis (HD) and peritoneal dialysis (PD).This prospective cohort observational study included a total of 253 ESRD patients who came to our hospital for HD or PD from February 2013 to February 2015. Enzyme linked immunosorbent assay (ELISA) method was used to detect the serum level of HMGB1, interleukin (IL-6), IL-8, and tumor necrosis factor-alpha (TNF-α). The kidney disease quality of life short form (KDQOL-SF) and kidney disease targeted area (KDTA) was applied for evaluating the quality of life. Kaplan-Meier (K-M) curve was performed for survival time.Serum level of HMGB1 in patients on HD was higher than PD. HMGB1 levels were gradually decreased with the treatment of HD or PD. Furthermore, HMGB1 was positively correlated with IL-6 and TNF-α. Moreover, patients with higher HMGB1 had more complications than patients with lower HMGB1, but there was no difference for the survival rate. In addition, the quality of life was associated with different dialysis methods.The serum level of HMGB1 and prognosis of ESRD patients was associated with different dialysis methods.

HMGB1, the Next Predictor of Transcatheter Arterial Chemoembolization for Liver Metastasis of Colorectal Cancer?

HMGB1 is an important mediator of inflammation during ischemia-reperfusion injury on organs. The serum expression of HMGB1 was increased significantly on the 1st day after TACE and decreased significantly which was lower on the 30th day after TACE. Tumor markers of post-DEB-TACE decreased significantly. The correlational analysis showed that patients with low HMGB1 expression had lower risks of fever and liver injury compared those with the higher expression, while the ORR is relatively worse. Patients with lower expression of HMGB1 had longer PFS, better efficacy, and higher quality of life. With the high post-expression, the low expression had lower incidence of fever and liver injury too. There was no statistical difference in the one-year survival among the different groups. The quality of life of all patients was improved significantly. The over-expression of HMGB1 in LMCRC is an adverse prognostic feature and a positive predictor of response to TACE.

LncRNA OIP5‑AS1 aggravates house dust mite‑induced inflammatory responses in human bronchial epithelial cells via the miR‑143‑3p/HMGB1 axis

Bronchial asthma poses a serious threat to human health. Previous studies have documented the role of long non‑coding RNAs (lncRNAs) in asthma. However, the molecular mechanism underlying bronchial asthma remains unclear. The aim of the present study was to evaluate the role of the lncRNA Opa‑interacting protein 5 antisense RNA1 (OIP5‑AS1) in the house dust mite‑induced inflammatory response in human bronchial epithelial cells. BEAS‑2B cells were treated with Dermatophagoides pteronyssinus peptidase 1 (Der p1) to establish an in vitro model of asthma. OIP5‑AS1 expression levels increased in BEAS‑2B cells following Der p1 treatment, while microRNA (miR)‑143‑3p was downregulated. Additionally, the levels of the pro‑inflammatory factors tumor necrosis factor‑α, interleukin (IL)‑6 and IL‑8 were measured, and apoptosis was evaluated following OIP5 silencing. OIP5‑AS1 knockdown reduced the inflammatory response and apoptosis in BEAS‑2B cells. Furthermore, using dual luciferase reporter assays and co‑transfection experiments, it was demonstrated that the function of OIP5‑AS1 was mediated by miR‑143‑3p. miR‑143‑3p overexpression attenuated the Der p1‑induced inflammatory response and apoptosis of BEAS‑2B cells by targeting high mobility group box 1 (HMGB1). In summary, OIP5‑AS1 exacerbated Der p1‑induced inflammation and apoptosis in BEAS‑2B cells by targeting miR‑143‑3p via HMGB1.

Oroxyloside ameliorates acetaminophen-induced hepatotoxicity by inhibiting JNK related apoptosis and necroptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Oroxyloside is a natural flavonoid isolated from Scutellaria baicalensis Georgi (Lamiaceae) which is a Chinese herb widely used for liver diseases. However, its mechanisms on protecting against drug induced liver injury has not been investigated yet.

AIM OF THE STUDY

To investigate the protecting effects and the primary mechanisms of oroxyloside on acetaminophen (APAP)-induced liver injury.

MATERIALS AND METHODS

After a 12 h fasting period with free access to water, C57BL/6 mice were injected with APAP (300 mg/kg) intragastrically (i.g.) and 1 h later with oroxyloside (100 mg/kg, i.g.). When mice sacrificed, blood samples were collected from fundus venous plexus and liver tissues were collected. In addition, cells were incubated with 10 mM APAP alone and 10 mM APAP combined with 100 μM oroxyloside for 24 h. ELISA, TUNEL assay, qRT-PCR et al. were used to assess the effect of oroxyloside on ameliorating APAP-induced hepatotoxicity in vitro and in vivo. Western bolt and immunohistochemistry were used in the signaling pathway analysis.

RESULTS

Oroxyloside administration significantly decreased the accumulations of CYP2E1, CYP1A2, IL-6, IL-1β, ALT and AST induced by APAP in vivo. In addition, oroxyloside inhibited the APAP-induced JNK related apoptosis by enhancing the antioxidant defenses, reversing ER-stress and keeping the mito-balance of liver cells in vivo and in vitro. Furthermore, oroxyloside protected the liver cells from necroptosis by affecting JNK pathway.

CONCLUSION

Oroxyloside acted as a protective agent against APAP-induced liver injury through inhibiting JNK-related apoptosis and necroptosis.

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.

Effect of fosinopril on the renal cortex protein expression profile of Otsuka Long-Evans Tokushima Fatty rats

Angiotensin-converting enzyme inhibitors (ACEIs) can reduce urinary protein excretion and postpone the deterioration of renal function. However, the mechanisms of renal protection are not yet fully understood. To investigate the mechanisms of ACEIs in the treatment of diabetic nephropathy (DN), the present study determined the effects of the ACEI fosinopril (FP) on the profiling of renal cortex protein expression in Otsuka Long-Evans Tokushima Fatty (OLETF) rats using Long-Evans Tokushima Otsuka (LETO) rats as controls. Urinary protein levels at 24 h were examined using the Broadford method. PAS staining was performed to observe renal histopathological changes. The kidney cortices of OLETF, FP-treated OLETF and LETO rats were examined using soluble and insoluble high-resolution subproteomic analysis methodology at age of 36 and 56 weeks. Differentiated proteins were further confirmed using western blotting analysis. The results demonstrated that FP significantly decreased the glomerulosclerosis index and reduced the 24 h urinary protein excretion of OLETF rats. Additionally, 17 proteins significantly changed following FP-treatment. Amongst these proteins, the abundances of the stress-response protein heat shock protein family A member 9 and the antioxidant glutathione peroxidase 3 were particularly increased. These results indicated that FP ameliorated diabetic renal injuries by inhibiting oxidative stress. In conclusion, the differentially expressed proteins may improve our understanding of the mechanism of ACEIs in the OLETF rats.

Mechanism of glycyrrhizin on ferroptosis during acute liver failure by inhibiting oxidative stress

The present study aimed to investigate the anti‑ferroptosis effects of the HMGB1 inhibitor glycyrrhizin (GLY). The present study used a cell and animal model of acute liver failure (ALF), induced using tumor necrosis factor‑α, lipopolysaccharide and D‑galactosamine, to investigate the effects of GLY. The expression of glutathione peroxidase 4 (GPX4) and high mobility group protein B1 (HMGB1), heme oxygenase‑1 (HO‑1) and nuclear factor erythroid 2‑related factor 2 (Nrf2) were detected were detected by western blotting in L02 hepatocytes and mouse liver. The expression of GPX4 and HMGB1 in L02 hepatocytes and mouse liver was detected by immunofluorescence. The pathological changes to liver tissues were determined by hematoxylin and eosin staining. The levels of lactate dehydrogenase (LDH), Fe2+, reactive oxygen species (ROS) and glutathione (GSH) were tested using kits. Compared with the normal group, the degree of liver damage and liver function in the model animal group was severe. The protein levels of HMGB1 in L02 cells and liver tissues were significantly increased. The expression of NRF2, HO‑1 and GPX4 was significantly decreased. The levels of LDH, Fe2+, malondialdehyde (MDA) and ROS were increased, whereas the level of GSH was decreased. Treatment with GLY reduced the degree of liver damage, the expression of HMGB1 was decreased, and the levels of Nrf2, HO‑1 and GPX4 were increased. The levels of LDH, Fe2+, MDA, ROS were decreased, while the level of GSH was increased by GLY treatment. The results of the present study indicated that HMGB1 is involved in the process of ferroptosis. The HMGB1 inhibitor GLY significantly reduced the degree of ferroptosis during ALF by inhibiting oxidative stress.

Baicalin Inhibits Haemophilus Parasuis-Induced High-Mobility Group Box 1 Release during Inflammation

Haemophilus parasuis (H. parasuis) can cause Glässer’s disease in pigs. However, the molecular mechanism of the inflammation response induced by H. parasuis remains unclear. The high-mobility group box 1 (HMGB1) protein is related to the pathogenesis of various infectious pathogens, but little is known about whether H. parasuis can induce the release of HMGB1 in piglet peripheral blood monocytes. Baicalin displays important anti-inflammatory and anti-microbial activities. In the present study, we investigated whether H. parasuis can trigger the secretion of HMGB1 in piglet peripheral blood monocytes and the anti-inflammatory effect of baicalin on the production of HMGB1 in peripheral blood monocytes induced by H. parasuis during the inflammation response. In addition, host cell responses stimulated by H. parasuis were determined with RNA-Seq. The RNA-Seq results showed that H. parasuis infection provokes the expression of cytokines and the activation of numerous pathways. In addition, baicalin significantly reduced the release of HMGB1 in peripheral blood monocytes induced by H. parasuis. Taken together, our study showed that H. parasuis can induce the release of HMGB1 and baicalin can inhibit HMGB1 secretion in an H. parasuis-induced peripheral blood monocytes model, which may provide a new strategy for preventing the inflammatory disorders induced by H. parasuis.