HMGB1 contributes to the irradiation-induced endothelial barrier injury through receptor for advanced glycation endproducts (RAGE)

Keratin7 and Desmoplakin are involved in acute lung injury induced by sepsis through RAGE

Keratin 7 (Krt7) is a member of the keratin family and is primarily involved in cytoskeleton composition. It has been shown that Krt7 is able to influence its own remodeling and interactions with other signaling molecules via phosphorylation at specific sites unique to Krt7. However, its molecular mechanism in acute lung injury (ALI) remains unclear. In this study, differential proteomics was used to analyze lung samples from the receptor for advanced glycation end products (RAGE)-deficient and (wild-type)WT-septic mice. We screened for the target protein Krt7 and identified Ser53 as the phosphorylation site using mass spectrometry (MS), and this phosphorylation further triggered the deformation and disintegration of Desmoplakin (Dsp), ultimately leading to epithelial barrier dysfunction. Furthermore, we demonstrated that in sepsis, mDia1/Cdc42/p38 MAPK signaling activation plays a role in septic lung injury. We also explored the mechanism of alveolar dysfunction of the Krt7-Dsp complex in the epithelial cell barrier. In summary, the present findings increase our understanding of the pathogenesis of septic acute lung injury.

The Redox Protein High-Mobility Group Box 1 in Cell Death and Cancer

Significance: As a redox-sensitive protein, high-mobility group box 1 (HMGB1) is implicated in regulating stress responses to oxidative damage and cell death, which are closely related to the pathology of inflammatory diseases, including cancer. Recent Advances: HMGB1 is a nonhistone nuclear protein that acts as a deoxyribonucleic acid chaperone to control chromosomal structure and function. HMGB1 can also be released into the extracellular space and function as a damage-associated molecular pattern protein during cell death, including during apoptosis, necrosis, necroptosis, pyroptosis, ferroptosis, alkaliptosis, and cuproptosis. Once released, HMGB1 binds to membrane receptors to shape immune and metabolic responses. In addition to subcellular localization, the function and activity of HMGB1 also depend on its redox state and protein posttranslational modifications. Abnormal HMGB1 plays a dual role in tumorigenesis and anticancer therapy (e.g., chemotherapy, radiation therapy, and immunotherapy) depending on the tumor types and stages. Critical Issues: A comprehensive understanding of the role of HMGB1 in cellular redox homeostasis is important for deciphering normal cellular functions and pathological manifestations. In this review, we discuss compartmental-defined roles of HMGB1 in regulating cell death and cancer. Understanding these advances may help us develop potential HMGB1-targeting drugs or approaches to treat oxidative stress-related diseases or pathological conditions. Future Directions: Further studies are required to dissect the mechanism by which HMGB1 maintains redox homeostasis under different stress conditions. A multidisciplinary effort is also required to evaluate the potential applications of precisely targeting the HMGB1 pathway in human health and disease. Antioxid. Redox Signal. 39, 569-590.

Cannabinoid receptor type 1 in the aging gut regulates the mucosal permeability via miR-191-5p

Background

Aging is associated with a broad loss of function throughout the body, and gastrointestinal (GI) dysfunction can occur with aging. The endocannabinoid (eCB) system plays a pivotal role in various GI diseases, and alterations in the eCB system have been observed during brain and skin aging. Therefore, we investigated the putative role of the eCB system in aging-related changes in the intestine.

Methods

The expression of cannabinoid receptor type 1 (CB1) was investigated in rat intestinal tissues using quantitative real-time PCR. Cellular senescence was induced by hydrogen peroxide (H2O2) and hydroxyurea (HU) in rat and human intestinal epithelial cells. Cellular permeability was evaluated by transepithelial electrical resistance (TEER) measurement.

Results and Discussion

The expression of CB1 was decreased in the small intestine of aged rats compared to that of young rats. Senescent cells showed reduced TEER values and decreased expression of ZO-1, indicating increased intestinal permeability, which is tightly regulated by the CB1 signaling. In silico miRNA analysis suggested that ZO-1 was a direct target gene of miR-191-5p. Increased expression of miR-191-5p by HU was restored by CB1 agonist ACEA co-treatment. Moreover, NF-κB p65 activation was associated with CB1-related miR-191-5p signaling. In conclusion, aging-induced CB1 reduction leads to increased intestinal permeability and decreased ZO-1 expression via upregulation of miR-191-5p and NF-κB p65 activation. Taken together, these results suggest that CB1 signaling may be a useful strategy to reduce intestinal permeability in aging-related and other inflammatory conditions in the gut.

Wumei Wan attenuates angiogenesis and inflammation by modulating RAGE signaling pathway in IBD: Network pharmacology analysis and experimental evidence

BACKGROUND

Wumei Wan (WMW) has been used to address digestive disorder for centuries in traditional Chinese medicine. Previous studies have demonstrated its anti-colitis efficacy, but the underlying mechanism of its action remains to be further clarified.

PURPOSE

To investigate the underlying mechanisms of WMW in the treatment of chronic ulcerative colitis (UC) through network pharmacology and experimental validation.

METHODS

Traditional Chinese Medicine Systems Pharmacology (TCMSP) platform were used to identify the ingredients and potential targets of WMW. The microarray gene data GSE75214 datasets from GEO database was used to define UC-associated targets. Cytoscape3.7.2 was employed to construct the protein-protein interaction (PPI) network and compounds-disease targets network. GO enrichment analysis and KEGG pathway analysis were performed by R software for functional annotation. UPLC-TOF-MS/MS method was used to quantitatively analyze the active ingredients of WMW. For experimental validation, three cycles of 2% dextran sulfate sodium salt (DSS) were used to construct chronic colitis model. The hub targets and signal pathway were detected by qPCR, ELISA, western blotting , immunohistochemical and immunofluorescence.

RESULTS

Through network analysis, 104 active ingredients were obtained from WMW, and 47 of these ingredients had potential targets for UC. A total of 41 potential targets of WMW and 13 hub targets were identified. KEGG analysis showed that WMW involved in advanced glycation end products-receptor of advanced glycation end products (AGE-RAGE) signaling pathway. Taxifolin, rutaecarpine, kaempferol, quercetin, and luteolin of WMW were the more highly predictive components related to the AGE-RAGE signaling pathway. In vivo validation, WMW improved DSS-induced colitis, reduced the expression of inflammatory cytokines and chemokines. Notably, it significantly decreased the mRNA expression of Spp1, Serpine1, Mmp2, Mmp9, Ptgs2, Nos2, Kdr and Icam1, which were associated with angiogenesis. In addition, we confirmed WMW inhibited RAGE expression and diminished DSS-induced epithelial barrier alterations CONCLUSION: Our results initially demonstrated the effective components and the strong anti-angiogenic activity of WMW in experimental chronic colitis. Sufficient evidence of the satisfactory anti-colitis action of WMW was verified in this study, suggesting its potential as a quite prospective agent for the therapy of UC.

Association of the RAGE/RAGE-ligand axis with interstitial lung disease and its acute exacerbation

The receptor for advanced glycation end product (RAGE) is a transmembrane receptor highly expressed in type 1 pneumocytes of healthy lungs. RAGE is considered to play a homeostatic role in the lung, as RAGE knockout mice develop lung fibrosis as they age. In contrast, RAGE can bind numerous ligands, including high-mobility group box 1 (HMGB1). These interactions initiate pro-inflammatory signaling associated with the pathogenesis of lung injury and interstitial lung disease (ILD), including idiopathic pulmonary fibrosis (IPF). ILD is a broad category of diffuse parenchymal lung disease characterized by various extents of lung fibrosis and inflammation, and IPF is a common and progressive ILD of unknown cause. The prognosis of patients with IPF is poor, and acute exacerbation of IPF (AE-IPF) is one of the main causes of death. Recent reports indicate that acute exacerbations can occur in other ILDs (AE-ILD). Notably, ILD is frequently observed in patients with lung cancer, and AE-ILD after surgical procedures or the initiation of chemotherapy for concomitant lung cancer are clinically important due to their association with increased mortality. In this review, we summarize the associations of RAGE/soluble RAGE (sRAGE)/RAGE ligands with the pathogenesis and clinical course of ILD, including IPF and AE-IPF. Additionally, the potential use of sRAGE and RAGE ligands as predictive markers of AE-IPF and cancer treatment-triggered AE-ILD is also discussed.

Ferroptosis and its role in cardiomyopathy

Heart disease is the leading cause of death worldwide. Cardiomyopathy is a disease characterized by the heart muscle damage, resulting heart in a structurally and functionally change, as well as heart failure and sudden cardiac death. The key pathogenic factor of cardiomyopathy is the loss of cardiomyocytes, but the related molecular mechanisms remain unclear. Ferroptosis is a newly discovered regulated form of cell death, characterized by iron accumulation and lipid peroxidation during cell death. Recent studies have shown that ferroptosis plays an important regulatory roles in the occurrence and development of many heart diseases such as myocardial ischemia/reperfusion injury, cardiomyopathy and heart failure. However, the systemic association of ferroptosis and cardiomyopathy remains largely unknown and needs to be elucidated. In this review, we provide an overview of the molecular mechanisms of ferroptosis and its role in individual cardiomyopathies, highlight that targeting ferroptosis maybe a potential therapeutic strategy for cardiomyopathy therapy in the future.

Cardiovascular Dysfunction in COVID-19: Association Between Endothelial Cell Injury and Lactate

Coronavirus disease 2019 (COVID-19), an infectious respiratory disease propagated by a new virus known as Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), has resulted in global healthcare crises. Emerging evidence from patients with COVID-19 suggests that endothelial cell damage plays a central role in COVID-19 pathogenesis and could be a major contributor to the severity and mortality of COVID-19. Like other infectious diseases, the pathogenesis of COVID-19 is closely associated with metabolic processes. Lactate, a potential biomarker in COVID-19, has recently been shown to mediate endothelial barrier dysfunction. In this review, we provide an overview of cardiovascular injuries and metabolic alterations caused by SARS-CoV-2 infection. We also propose that lactate plays a potential role in COVID-19-driven endothelial cell injury.

Anti-high-mobility group box-1 (HMGB1) mediates the apoptosis of alveolar epithelial cells (AEC) by receptor of advanced glycation end-products (RAGE)/c-Jun N-terminal kinase (JNK) pathway in the rats of crush injuries

Objectives

The lung injury is often secondary to severe trauma. In the model of crush syndrome, there may be secondary lung injury. We hypothesize that high-mobility group box 1 (HMGB1), released from muscle tissue, mediates the apoptosis of alveolar epithelial cells (AEC) via HMGB1/Receptor of advanced glycation end-products (RAGE)/c-Jun N-terminal kinase (JNK) pathway. The study aimed to investigate how HMGB1 mediated the apoptosis of AEC in the rat model.

Methods

Seventy-five SD male rats were randomly divided into five groups: CS, CS + vehicle, CS + Ethyl pyruvate (EP), CS + FPS-ZM1 group, and CS + SP600125 groups. When the rats CS model were completed after 24 h, the rats were sacrificed. We collected the serum and the whole lung tissues. Inflammatory cytokines were measured in serum samples. Western blot and RT-qPCR were used to quantify the protein and mRNA. Lastly, apoptotic cells were detected by TUNEL. We used SPSS 25.0 for statistical analyses.

Results

Nine rats died during the experiments. Dead rats were excluded from further analysis. Compared to the CS group, levels of HMGB1 and inflammatory cytokines in serum were downregulated in CS + EP, CS + FPS-ZM1, and CS + SP600125 groups. Western blot and RT-qPCR analysis revealed a significant downregulation of HMGB1, RAGE, and phosphorylated-JNK in CS + EP, CS + FPS-ZM1, and CS + SP600125 groups, compared with the CS groups, excluding total-JNK mRNA. Apoptosis of AEC was used TUNEL to assess. We found the TUNEL-positive cells were downregulated in CS + EP, CS + FPS-ZM1, and CS + SP600125 groups.

Conclusion

The remote lung injury begins early after crush injuries. The HMGB1/RAGE/JNK signaling axis is an attractive target to abrogate the apoptosis of AEC after crush injuries.

In Vitro Methodologies to Study the Role of Advanced Glycation End Products (AGEs) in Neurodegeneration

Advanced glycation end products (AGEs) can be present in food or be endogenously produced in biological systems. Their formation has been associated with chronic neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and amyotrophic lateral sclerosis. The implication of AGEs in neurodegeneration is related to their ability to bind to AGE-specific receptors and the ability of their precursors to induce the so-called “dicarbonyl stress”, resulting in cross-linking and protein damage. However, the mode of action underlying their role in neurodegeneration remains unclear. While some research has been carried out in observational clinical studies, further in vitro studies may help elucidate these underlying modes of action. This review presents and discusses in vitro methodologies used in research on the potential role of AGEs in neuroinflammation and neurodegeneration. The overview reveals the main concepts linking AGEs to neurodegeneration, the current findings, and the available and advisable in vitro models to study their role. Moreover, the major questions regarding the role of AGEs in neurodegenerative diseases and the challenges and discrepancies in the research field are discussed.

Radiation-induced neuroinflammation: a potential protective role for poly(ADP-ribose) polymerase inhibitors?

Radiotherapy (RT) plays a fundamental role in the treatment of glioblastoma (GBM). GBM are notoriously invasive and harbor a subpopulation of cells with stem-like features which exhibit upregulation of the DNA damage response (DDR) and are radioresistant. High radiation doses are therefore delivered to large brain volumes and are known to extend survival but also cause delayed toxicity with 50%-90% of patients developing neurocognitive dysfunction. Emerging evidence identifies neuroinflammation as a critical mediator of the adverse effects of RT on cognitive function. In addition to its well-established role in promoting repair of radiation-induced DNA damage, activation of poly(ADP-ribose) polymerase (PARP) can exacerbate neuroinflammation by promoting secretion of inflammatory mediators. Therefore, PARP represents an intriguing mechanistic link between radiation-induced activation of the DDR and subsequent neuroinflammation. PARP inhibitors (PARPi) have emerged as promising new agents for GBM when given in combination with RT, with multiple preclinical studies demonstrating radiosensitizing effects and at least 3 compounds being evaluated in clinical trials. We propose that concomitant use of PARPi could reduce radiation-induced neuroinflammation and reduce the severity of radiation-induced cognitive dysfunction while at the same time improving tumor control by enhancing radiosensitivity.

Roles of RAGE/ROCK1 Pathway in HMGB1-Induced Early Changes in Barrier Permeability of Human Pulmonary Microvascular Endothelial Cell

Background

High mobility group box 1 (HMGB1) causes microvascular endothelial cell barrier dysfunction during acute lung injury (ALI) in sepsis, but the mechanisms have not been well understood. We studied the roles of RAGE and Rho kinase 1 (ROCK1) in HMGB1-induced human pulmonary endothelial barrier disruption.

Methods

In the present study, the recombinant human high mobility group box 1 (rhHMGB1) was used to stimulate human pulmonary microvascular endothelial cells (HPMECs). The endothelial cell (EC) barrier permeability was examined by detecting FITC-dextran flux. CCK-8 assay was used to detect cell viability under rhHMGB1 treatments. The expression of related molecules involved in RhoA/ROCK1 pathway, phosphorylation of myosin light chain (MLC), F-actin, VE-cadherin and ZO-1 of different treated groups were measured by pull-down assay, western blot and immunofluorescence. Furthermore, we studied the effects of Rho kinase inhibitor (Y-27632), ROCK1/2 siRNA, RAGE-specific blocker (FPS-ZM1) and RAGE siRNA on endothelial barrier properties to elucidate the related mechanisms.

Results

In the present study, we demonstrated that rhHMGB1 induced EC barrier hyperpermeability in a dose-dependent and time-dependent manner by measuring FITC-dextran flux, a reflection of the loss of EC barrier integrity. Moreover, rhHMGB1 induced a dose-dependent and time-dependent increases in paracellular gap formation accompanied by the development of stress fiber rearrangement and disruption of VE-cadherin and ZO-1, a phenotypic change related to increased endothelial contractility and endothelial barrier permeability. Using inhibitors and siRNAs directed against RAGE and ROCK1/2, we systematically determined that RAGE mediated the rhHMGB1-induced stress fiber reorganization via RhoA/ROCK1 signaling activation and the subsequent MLC phosphorylation in ECs.

Conclusion

HMGB1 is capable of disrupting the endothelial barrier integrity. This study demonstrates that HMGB1 activates RhoA/ROCK1 pathway via RAGE, which phosphorylates MLC inducing stress fiber formation at short time, and HMGB1/RAGE reduces AJ/TJ expression at long term independently of RhoA/ROCK1 signaling pathway.

Glycyrrhizin ameliorating sterile inflammation induced by low-dose radiation exposure

Glycyrrhizin (GL) is a direct inhibitor of HMGB1 which acts as an alarmin when excreted into the extracellular space. High-dose radiation in radiotherapy induces collateral damage to the normal tissue, which can be mitigated by GL inhibiting HMGB1. The purpose of this study was to assess changes in HMGB1 and pro-inflammatory cytokines and to evaluate the protective effect of GL after low-dose radiation exposure. BALB/c mice were irradiated with 0.1 Gy (n = 10) and 1 Gy (n = 10) with GL being administered to half of the mice (n = 5, respectively) before irradiation. Blood and spleen samples were harvested and assessed for oxidative stress, HMGB1, pro-inflammatory cytokines, and cell viability. HMGB1 and pro-inflammatory cytokines increased and cell viability decreased after irradiation in a dose-dependent manner. Oxidative stress also increased after irradiation, but did not differ between 0.1 Gy and 1 Gy. With the pretreatment of GL, oxidative stress, HMGB1, and all of the pro-inflammatory cytokines decreased while cell viability was preserved. Our findings indicate that even low-dose radiation can induce sterile inflammation by increasing serum HMGB1 and pro-inflammatory cytokines and that GL can ameliorate the sterile inflammatory process by inhibiting HMGB1 to preserve cell viability.

Gamma Radiation Induce Inflammasome Signaling and Pyroptosis in Microvascular Endothelial Cells

Introduction

The extend to the clinical benefit of radiation therapy is the inability to eliminate only cancer cells and destroy normal cells such as microvascular endothelial in the vascular niche and turn induced-inflammasome signaling and cell death. These unfortunate injuries generated by ionizing radiation alter the therapeutic window and result in the re-occurrence of the malignancy. Therefore, we engaged in vitro studies by demonstrating radiation-induced inflammasome and cell death in endothelial cells.

Methods

The microvascular endothelial cells were cultured in a sterile dish, then kept in a humidifier of 5% at 37°C for 12 hours/more to attain confluence, and exposed at a dose of 1.8Gy/min achieve the coveted amounts except for the control. The cells were harvested 24 hours post-irradiation.

Results

Our findings indicate that gamma radiation activates the NOD-like receptor (NLR) family of NLRP1 and NLRP3 complex in microvascular endothelial cells. These complexes activate the inactive precursor of caspase-1, which cleaved to bioactive caspase −1 and enhances the production of pro-inflammatory cytokines of interleukin-1β and interleukin-18 that induce the dependent pyroptotic, which results in the production of chemokines, tumor necrosis factor-alpha (TNF-α), and high-mobility group protein-1 (HMGB-1). We also discovered the radiation could directly prompt caspase −1, which auto-cleaved to activate gasdermin D to potentiate pyroptosis independently.

Discussion

Overall, these findings suggested that reducing the unfavorable effect of radiation injuries could be challenging since gamma radiation induces the microvascular endothelial cells to cell death and activates the inflammasome signaling via different pathways.

The role of irreversible electroporation in promoting M1 macrophage polarization via regulating the HMGB1-RAGE-MAPK axis in pancreatic cancer

Irreversible electroporation (IRE) is an effective method for treating pancreatic ductal adenocarcinoma (PDAC). It remains unclear whether IRE can induce a specific immune response by stimulating macrophages. Here, the associated markers of macrophages were analyzed after exposure to tumor culture supernatant (TSN) of tumor cells treated with electroporation. Subcutaneous and orthotopic PDAC models were also used to evaluate the effect of macrophage polarization induced by IRE. Aside from its direct killing effect, IRE could induce the immunogenic cell death of tumor cells by increasing the synthesis and secretion of damage associated molecular patterns. Moreover, IRE could increase the release of HMGB1, which activates the MAPK-p38 pathway and leads to the increased expression of M1 markers in macrophages, through binding to the receptor of the advanced glycation end-product (RAGE) receptor. M1 polarization was inhibited by the inhibitors of HMGB1 release, the RAGE receptor, and the MAPK-p38 signaling pathway, but it was activated by rHMGB1 or the stimulator of MAPK-p38. In addition, the promotion of M1 macrophage polarization was enhanced by the positive-feedback release or expression of HMGB1 and RAGE through the MAPK-ERK pathway in macrophages. The promotion of M1 macrophage polarization induced by IRE provided a specific rationale for the combination of IRE and immune therapy in treating PDAC.

The receptor for advanced glycation end products mediates dysfunction of airway epithelial barrier in a lipopolysaccharides-induced murine acute lung injury model

BACKGROUND

Airway epithelial cells (AECs) act as the first barrier protecting against invasion of environment agents and maintain integrity of lung structure and function. Dysfunction of airway epithelial barrier has been shown to be involved in ALI/ARDS pathogenesis. Yet, the exact mechanism is still obscure. Our study evaluated whether the receptor for advanced glycation end products (RAGE) mediates impaired airway epithelial barrier in LPS-induced murine ALI model.

METHODS

Male BALB/c mice were subjected to intratracheal instillation of LPS to generate an ALI model. Inhibitors of RAGE, FPS-ZM1 and Azeliragon were respectively given to the mice through intraperitoneal injection. Bronchoalveolar lavage fluid (BALF) and lung tissues were collected for further analysis.

RESULTS

LPS exposure led to markedly increased expression of RAGE and its ligands HMGB1, HSP70, S100b. Treatment of FPS-ZM1 or Azeliragon not only effectively descended the expression of RAGE and its ligands but also attenuated LPS-induced neutrophil-predominant airway inflammation and injury, decreased levels of IL-6, IL-1β and TNF-α in BALF, alleviated increased alveolar-capillary permeability and pulmonary edema. LPS stimulation significantly impaired the integrity of airway epithelium, paralleled with dislocation of adheren junction (AJ) protein E-cadherin at cell-cell contacts and down-expression of both AJ and tight junction (TJ) proteins Claudin-2 and occludin, all of which were dramatically rescued by RAGE inhibition.

CONCLUSION

RAGE signaling mediates airway epithelial barrier dysfunction in a LPS-induced ALI murine model.

Receptor for Advanced Glycation End Products Is Involved in LPA5-Mediated Brain Damage after a Transient Ischemic Stroke

Lysophosphatidic acid receptor 5 (LPA₅) has been recently identified as a novel pathogenic factor for brain ischemic stroke. However, its underlying mechanisms remain unclear. Here, we determined whether the receptor for advanced glycation end products (RAGE) could be involved in LPA₅-mediated brain injuries after ischemic challenge using a mouse model of transient middle cerebral artery occlusion (tMCAO). RAGE was upregulated in the penumbra and ischemic core regions after tMCAO challenge. RAGE upregulation was greater at 3 days than that at 1 day after tMCAO challenge. It was mostly observed in Iba1-immunopositive cells of a post-ischemic brain. Suppressing LPA₅ activity with its antagonist, TCLPA5, attenuated RAGE upregulation in the penumbra and ischemic core regions, particularly on Iba1-immunopositive cells, of injured brains after tMCAO challenge. It also attenuated blood–brain barrier disruption, one of the core pathogenesis upon RAGE activation, after tMCAO challenge. As an underlying signaling pathways, LPA₅ could contribute to the activation of ERK1/2 and NF-κB in injured brains after tMCAO challenge. Collectively, the current study suggests that RAGE is a possible mediator for LPA₅-dependent ischemic brain injury.

HMGB1 in Radiotherapy: A Two Headed Signal Regulating Tumor Radiosensitivity and Immunity

Radiotherapy (RT) is a mainstay of cancer treatment. Recent studies have shown that RT not only directly induces cell death but also has late and sustained immune effects. High mobility group box 1 (HMGB1) is a nuclear protein released during RT, with location-dependent functions. It is essential for normal cellular function but also regulates the proliferation and migration of tumor cells by binding to high-affinity receptors. In this review, we summarize recent evidence on the functions of HMGB1 in RT according to the position, intracellular HMGB1 and extracellular HMGB1. Intracellular HMGB1 induces radiation tolerance in tumor cells by promoting DNA damage repair and autophagy. Extracellular HMGB1 plays a more intricate role in radiation-related immune responses, wherein it not only stimulates the anti-tumor immune response by facilitating the recognition of dying tumor cells but is also involved in maintaining immunosuppression. Factors that potentially affect the role of HMGB1 in RT-induced cytotoxicity have also been discussed in the context of possible therapeutic applications, which helps to develop effective and targeted radio-sensitization therapies.

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.

Bile duct ligation enhances AZT CNS toxicity partly by impairing the expression and function of BCRP in rat brain

Breast cancer resistance protein (BCRP) is one of ATP-binding cassette (ABC) transporters in brain microvessel endothelial cells that transport their substrates from brain to blood, thus limiting substrates to crossing into brain through blood-brain barrier. Our previous works show that bile duct ligation (BDL) impairs expression and function of brain BCRP in rats. Since zidovudine (AZT) is BCRP substrate, we investigated whether impaired expression and function of BCRP increased brain distribution and toxicity of AZT in BDL-D7 rats. After administration of AZT (10 mg/kg, i.v.), BDL markedly increased brain AZT concentrations, compared with sham-operated (SO) rats. The ratio of AZT brain-to-plasma area under concentration curve (AUC) in BDL rats was increased to 1.6-folds of SO rats. After treatment with AZT (100 mg/kg every day, i.v.) for 7 days, BDL significantly impaired cognitive functions compared with SO rats, evidenced by the significantly decreased percentage of alternation in Y-maze test and prolonged escaped latency in two-way passive avoidance trial. Furthermore, AZT treatment caused significant decrease in copies of mitochondrial DNA and mitochondrial membrane potential in hippocampus of BDL rats. Moreover, AZT treatment caused a significant decrease of cortex microtubule-associated protein 2 and hippocampus synaptophysin levels in BDL rats. AZT-induced CNS adverse alterations in BDL rats were not observed in SO rats treated with AZT. In conclusion, BDL decreases the function and expression of brain BCRP in rats, leading to increased brain distribution of AZT, which in turn enhances AZT CNS toxicity, leading to mitochondrial dysfunction, neuronal damage, and ultimately cognitive dysfunction.

A translational concept of immuno-radiobiology

BACKGROUND

Traditional concepts of radiobiology model the direct radiation-induced cellular cytotoxicity but are not focused on late and sustained effects of radiation. Recent experimental data show the close involvement of immunological processes.

METHODS

Based on systematic PubMed searches, experimental data on immunological radiation effects are summarized and analyzed in a non-quantitative descriptive manner to provide a translational perspective on the immuno-modulatory impact of radiation in cancer.

RESULTS

Novel experimental findings document that sustained radiation effects are ultimately mediated through systemic factors such as cytotoxic CD8+ T cells and involve a local immuno-stimulation. Increased tumor infiltration of CD8+ T cell is a prerequisite for long-term radiation effects. CD8+ T cell depletion induces radio-resistance in experimental tumors. The proposed sequence of events involves radiation-damaged cells that release HMGB1, which activates macrophages via TLR4 to a local immuno-stimulation via TNF, which contributes to maturation of DCs. The mature DCs migrate to lymph nodes where they trigger effective CD8+ T cell responses. Radiation effects are boosted, when the physiological self-terminating negative feedback of immune reactions is antagonised via blocking of TGF-β or via checkpoint inhibition with involvement of CD8+ T cells as common denominator.

CONCLUSION

The concept of immuno-radiobiology emphasizes the necessity for a functional integrity of APCs and T cells for the long-term effects of radiotherapy. Local irradiation at higher doses induces tumor infiltration of CD8+ T cells, which can be boosted by immunotherapy. More systematic research is warranted to better understand the immunological effects of escalating radiation doses.

Inhibition of the receptor for advanced glycation inhibits lipopolysaccharide-mediated High mobility group protein B1 and Interleukin-6 synthesis in human gingival fibroblasts through the NF-κB signaling pathway

AIMS

We investigated the effect of a specific inhibitor of the receptor for advanced glycation (FPS-ZM1) against lipopolysaccharide (LPS)-induced increase in expressions of high mobility group protein B1 (HMGB1) and interleukin-6 (IL-6) in human gingival fibroblasts (HGFs). Furthermore, we explored the potential molecular mechanisms and assessed the involvement of the NF-κB pathway in mediating the changes in the expressions of HMGB1 and IL-6 expression in response to LPS and FPS-ZM1.

METHODS

HGFs were cultured with enzymatic digestion-tissue explants method. The proliferation of LPS-stimulated HGFs pretreated with FPS-ZM1 at 24, 48, and 72 h was determined by cell counting kit 8 assay. The expressions of HMGB1 and IL-6 were measured using quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. Western blot analysis was used to assess the expressions of receptor for advanced glycation end products (RAGE) and NF-κB.

RESULTS

LPS enhanced the protein expression of RAGE in HGFs. At the same time, LPS stimulated mRNA and protein expressions of HMGB1 and IL-6 in HGFs. However, pretreatment with FPS-ZM1 attenuated these effects. Pretreatment with FPS-ZM1 (250, 500 nM) significantly inhibited the LPS-induced NF-κB activity.

CONCLUSION

FPS-ZM1 down-regulated the LPS-induced HMGB1 and IL-6 expression in HGFs through blocking NF-κB activation. FPS-ZM1 is a promising therapeutic agent for inflammatory diseases caused by oral bacteria.

HMGB1/RAGE pro-inflammatory axis promotes vascular endothelial cell apoptosis in limb ischemia/reperfusion injury

OBJECTIVE

High-Mobility Group Box 1 (HMGB1) promotes vascular injuries induced by limb Ischemia and Reperfusion (IR), but the molecular mechanisms are not well understood. This study aimed to investigate the role of Receptor for Advanced-Glycation End products (RAGE) in HMGB1-regulated inflammatory response and vascular injury in limb IR using the rat IR and cellular Hypoxia and Reoxygenation (HR) models.

METHODS

We analyzed the vascular structure and elastic fiber deposition in rat femoral arteries by histological staining. We determined gene expression in vascular tissues and cells by quantitative RT-PCR, Western blotting and immunofluorescence; analyzed the protein levels in rat serum or cell supernatant by ELISA; and assessed protein interaction by co-immunoprecipitation. We used CCK-8 for analyzing cell viability, and assessed apoptosis by Hoechst staining and flow cytometry.

RESULTS

RAGE inhibition by FPS-ZM1 significantly repressed rat vascular injury that was induced by limb IR treatment. HMGB1 and RAGE expression, P38, ERK1/2, P65 and IKBa phosphorylation, as well as HIF-1a, NLRP3, Caspase-1, TNF-a and IL-6 expression and P65 in nucleus, increased in femoral arteries of a rat IR model and HUVEC undergoing HR treatment, whereas all the factors except HMGB1 and RAGE were inhibited by FPS-ZM1 treatment. In addition, we found that HMGB1 binds with RAGE in HUVEC undergoing HR treatment, which was suppressed by FPS-ZM1. Finally, the apoptosis of HUVEC also increased by HR treatment, but repressed under FPS-ZM1 treatment.

CONCLUSION

HMGB1 binds with RAGE to promote vascular inflammation and endothelial cell apoptosis, which mediates vascular injury during acute limb IR.

Pathological effects of ionizing radiation: endothelial activation and dysfunction

The endothelium, a tissue that forms a single layer of cells lining various organs and cavities of the body, especially the heart and blood as well as lymphatic vessels, plays a complex role in vascular biology. It contributes to key aspects of vascular homeostasis and is also involved in pathophysiological processes, such as thrombosis, inflammation, and hypertension. Epidemiological data show that high doses of ionizing radiation lead to cardiovascular disease over time. The aim of this review is to summarize the current knowledge on endothelial cell activation and dysfunction after ionizing radiation exposure as a central feature preceding the development of cardiovascular diseases.

Blockade of receptors of advanced glycation end products ameliorates diabetic osteogenesis of adipose-derived stem cells through DNA methylation and Wnt signalling pathway

OBJECTIVES

Diabetes mellitus-related osteoporosis is caused by the imbalance between bone absorption and bone formation. Advanced glycation end products (AGEs) are considered a cause of diabetic osteoporosis. Although adipose-derived stem cells (ASCs) are promising adult stem cells in bone tissue regeneration, the ability of osteogenesis of ASCs in diabetic environment needs to explore. This study aimed to investigate the influence of AGEs on the osteogenic potential of ASCs and to explore the signalling pathways involved in its effect.

MATERIALS AND METHODS

ASCs were isolated from inguinal fat and cultured in osteogenic media with or without AGEs and FPS-ZM1, an inhibitor of receptor for AGEs (RAGE). Alizarin red-S, Oil Red-O and Alcian blue staining were used to confirm osteogenic, adipogenic and chondrogenic potential of ASCs, respectively. Immunofluorescence, western blotting and real-time PCR were used to measure changes in markers of osteogenic differentiation, DNA methylation and Wnt signalling.

RESULTS

The multipotentiality of ASCs was confirmed. Treated with AGEs, OPN and RUNX2 expressions of ASCs were reduced and there was a noticeable loss of mineralization, concomitant with an increase in the expression of RAGE, 5-MC, DNMT1 and DNMT3a. AGEs treatment also led to a loss of Wnt signalling pathway markers, including β-Catenin and LEF1, with an increase in GSK-3β. Treatment with the RAGE inhibitor, FPS-ZM1, rescued AGEs-induced loss of osteogenic potential, modulated DNA methylation and upregulated Wnt signalling in ASCs.

CONCLUSIONS

Our results demonstrate that AGEs-RAGE signalling inhibits the osteogenic potential of ASCs under osteoinductive conditions by modulating DNA methylation and Wnt signalling. FPS-ZM1 can rescue the negative effects of AGEs and provide a possible treatment for bone tissue regeneration in patients with diabetic osteoporosis.