The Janus face of HMGB1 in heart disease: a necessary update

Psychobiotics Lactiplantibacillus plantarum JYLP-326: Antidepressant-like effects on CUMS-induced depressed mouse model and alleviation of gut microbiota dysbiosis

BACKGROUND

Depression affects a significant portion of the global population and has emerged as one of the most debilitating conditions worldwide. Recent studies have explored the relationship between depression and the microbiota of the intestine, revealing potential avenues for effective treatment.

METHODS

To evaluate the potential alleviation of depression symptoms, we employed a depression C57BL/6 mice model induced by chronic unpredictable mild stress (CUMS). We administered Lactiplantibacillus plantarum JYLP-326 and conducted various animal behavior tests, including the open-field test (OFT), sucrose preference test (SPT), and tail-suspension test (TST). Additionally, we conducted immunohistochemistry staining and analyzed the hippocampal and colon parts of the mice.

RESULTS

The results of the behavior tests indicated that L. plantarum JYLP-326 alleviated spontaneous behavior associated with depression. Moreover, the treatment led to significant improvements in GFAP and Iba1, suggesting its potential neuroprotective effects. Analysis of the hippocampal region indicated that L. plantarum JYLP-326 administration upregulated p-TPH2, TPH2, and 5-HT1AR, while downregulating the expression of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α. In the colon, the treatment inhibited the TLR4-MyD88-NF-κB pathway and increased the levels of occludin and ZO-1, indicating improved intestinal barrier function. Additionally, the probiotic demonstrated a regulatory effect on the HMGB1-RAGE-TLR4 signaling pathway.

CONCLUSIONS

Our findings demonstrate that L. plantarum JYLP-326 exhibits significant antidepressant-like effects in mice, suggesting its potential as a therapeutic approach for depression through the modulation of gut microbiota. However, further investigations and clinical trials are required to validate its safety and efficacy for human use.

Glycyrrhizic Acid Alleviates Semen Strychni-Induced Neurotoxicity Through the Inhibition of HMGB1 Phosphorylation and Inflammatory Responses

The neurotoxicity of Semen Strychni has been reported recently in several clinical cases. Therefore, this study was conducted to investigate the role of HMGB1 in a model of neurotoxicity induced by Semen Strychni and to assess the potential alleviating effects of glycyrrhizic acid (GA), which is associated with the regulation of HMGB1 release. Forty-eight SD rats were intraperitoneally injected with Semen Strychni extract (175 mg/kg), followed by oral administration of GA (50 mg/kg) for four days. After treatment of SS and GA, neuronal degeneration, apoptosis, and necrosis were observed via histopathological examination. Inflammatory cytokines (TNF-α and IL-1β), neurotransmitter associated enzymes (MAO and AChE), serum HMGB1, nuclear and cytoplasmic HMGB1/ph-HMGB1, and the interaction between PP2A, PKC, and HMGB1 were evaluated. The influence of the MAPK pathway was also examined. As a result, this neurotoxicity was characterized by neuronal degeneration and apoptosis, the induction of pro-inflammatory cytokines, and a reduction in neurotransmitter-metabolizing enzymes. In contrast, GA treatment significantly ameliorated the abovementioned effects and alleviated nerve injury. Furthermore, Semen Strychni promoted HMGB1 phosphorylation and its translocation between the nucleus and cytoplasm, thereby activating the NF-κB and MAPK pathways, initiating various inflammatory responses. Our experiments demonstrated that GA could partially reverse these effects. In summary, GA acid alleviated Semen Strychni-induced neurotoxicity, possibly by inhibiting HMGB1 phosphorylation and preventing its release from the cell.

Berberine Improves Cancer-Derived Myocardial Impairment in Experimental Cachexia Models by Targeting High-Mobility Group Box-1

Cardiac disorders in cancer patients pose significant challenges to disease prognosis. While it has been established that these disorders are linked to cancer cells, the precise underlying mechanisms remain elusive. In this study, we investigated the impact of cancerous ascites from the rat colonic carcinoma cell line RCN9 on H9c2 cardiomyoblast cells. We found that the ascites reduced mitochondrial volume, increased oxidative stress, and decreased membrane potential in the cardiomyoblast cells, leading to apoptosis and autophagy. Although the ascites fluid contained a substantial amount of high-mobility group box-1 (HMGB1), we observed that neutralizing HMGB1 with a specific antibody mitigated the damage inflicted on myocardial cells. Our mechanistic investigations revealed that HMGB1 activated both nuclear factor κB and phosphoinositide 3-kinases-AKT signals through HMGB1 receptors, namely the receptor for advanced glycation end products and toll-like receptor-4, thereby promoting apoptosis and autophagy. In contrast, treatment with berberine (BBR) induced the expression of miR-181c-5p and miR-340-5p while suppressing HMGB1 expression in RCN9 cells. Furthermore, BBR reduced HMGB1 receptor expression in cardiomyocytes, consequently mitigating HMGB1-induced damage. We validated the myocardial protective effects of BBR in a cachectic rat model. These findings underscore the strong association between HMGB1 and cancer cachexia, highlighting BBR as a promising therapeutic agent for myocardial protection through HMGB1 suppression and modulation of the signaling system.

HMGB1-RAGE axis contributes to myocardial ischemia/reperfusion injury via regulation of cardiomyocyte autophagy and apoptosis in diabetic mice

Patients with acute myocardial infarction complicated with diabetes are more likely to develop myocardial ischemia/reperfusion (I/R) injury (MI/RI) during reperfusion therapy. Both HMGB1 and RAGE play important roles in MI/RI. However, the specific mechanisms of HMGB1 associated with RAGE are not fully clarified in diabetic MI/RI. This study aimed to investigate whether the HMGB1-RAGE axis induces diabetic MI/RI via regulating autophagy and apoptosis. A db/db mouse model of MI/RI was established, where anti-HMGB1 antibody and RAGE inhibitor (FPS-ZM1) were respectively injected after 10 min of reperfusion. The results showed that treatment with anti-HMGB1 significantly reduced the infarct size, serum LDH, and CK-MB level. Similar situations also occurred in mice administrated with FPS-ZM1, though the HMGB1 level was unchanged. Then, we found that treatment with anti-HMGB1 or FPS-ZM1 performed the same effects in suppressing the autophagy and apoptosis, as reflected by the results of lower LAMP2 and LC3B levels, increased Bcl-2 level, reduced BAX and caspase-3 levels. Moreover, the Pink1/Parkin levels were also inhibited at the same time. Collectively, this study indicates that the HMGB1-RAGE axis aggravated diabetic MI/RI via apoptosis and Pink1/Parkin mediated autophagy pathways, and inhibition of HMGB1 or RAGE contributes to alleviating those adverse situations.

Shared Proteins and Pathways of Cardiovascular and Cognitive Diseases: Relation to Vascular Cognitive Impairment

One of the primary goals of systems medicine is the detection of putative proteins and pathways involved in disease progression and pathological phenotypes. Vascular cognitive impairment (VCI) is a heterogeneous condition manifesting as cognitive impairment resulting from vascular factors. The precise mechanisms underlying this relationship remain unclear, which poses challenges for experimental research. Here, we applied computational approaches like systems biology to unveil and select relevant proteins and pathways related to VCI by studying the crosstalk between cardiovascular and cognitive diseases. In addition, we specifically included signals related to oxidative stress, a common etiologic factor tightly linked to aging, a major determinant of VCI. Our results show that pathways associated with oxidative stress are quite relevant, as most of the prioritized vascular cognitive genes and proteins were enriched in these pathways. Our analysis provided a short list of proteins that could be contributing to VCI: DOLK, TSC1, ATP1A1, MAPK14, YWHAZ, CREB3, HSPB1, PRDX6, and LMNA. Moreover, our experimental results suggest a high implication of glycative stress, generating oxidative processes and post-translational protein modifications through advanced glycation end-products (AGEs). We propose that these products interact with their specific receptors (RAGE) and Notch signaling to contribute to the etiology of VCI.

Gentisic acid ameliorates cisplatin-induced reprotoxicity through suppressing endoplasmic reticulum stress and upregulating Nrf2 pathway

Reproductive toxicity is a serious side effect of cisplatin (CP) chemotherapy. Gentisic acid (GTA) is a phenolic acid with strong antioxidant properties. Here, we aimed to determine therapeutic effect of GTA against CP-induced testicular toxicity in rats for the first time. Male Sprague-Dawley rats received a single dose of CP (5 mg/kg; intraperitoneal) and treated with GTA (1.5 and 3 mg/kg; intraperitoneal; 3 consecutive days). The levels of oxidative stress (OS), inflammation, endoplasmic reticulum stress (ERS) and apoptosis biomarkers were assessed in the testicular tissue of rats. In addition, how CP affects the nuclear factor erythroid-2-related factor 2 (Nrf2) pathway and the effect of GTA on this situation were also addressed in the testicular tissue. CP administration induced histopathological changes in testicular tissue of rats with a significant increase in OS, inflammation, ERS and apoptosis biomarkers and a decrease in antioxidant capacity and Nrf2 expression levels. Administrations of GTA resulted in an amelioration of these altered parameters. These data suggest that GTA may be a potential therapeutic agent against CP-induced testicular toxicity. Activation of the Nrf2 pathway plays a key role of this therapeutic effect of GTA.

Lipopolysaccharides protect mesenchymal stem cell against cardiac ischemia-reperfusion injury by HMGB1/STAT3 signaling

BACKGROUND

Myocardial ischemia-reperfusion (I/R) is a serious and irreversible injury. Bone marrow-derived mesenchymal stem cells (MSCs) is considered to be a potential therapy for I/R injury due to the paracrine effects. High-mobility group box 1 (HMGB1) is a novel mediator in MSC and regulates the response of inflammation injury. Signal Transduction and Transcription Activator 3 (STAT3) is a critical transcription factor and important for release of paracrine factors. However, the relationship between HMGB1 and STAT3 in paracrine effect of MSC remains unknown.

METHODS

In vitro, hypoxia/reoxygenation injury model was established by AnaeroPack System and examined by Annexin V flow cytometry, CCK8 assay and morphology observation. Detection of apoptotic proteins and protein expression of HMGB1 and STAT3 by Western blot.

RESULTS

The conditioned medium of MSCs with or without LPS pretreatment was cocultured with H9C2 cells for 24 h before hypoxia treatment and MSC showed obvious cardiomyocytes protect role, as evidence by decreased apoptosis rate and improved cells viability, and LPS pretreated MSC exhibited better protect role than untreated MSC. However, such effect was abolished in HMGB1 deficiency group, silencing HMGB1 decreased the secretion of vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), insulin growth factor (IGF), cell viability, and the expression of STAT3. Furthermore, STAT3 silence attenuated the protective effect of LPS in MSC.

CONCLUSIONS

These findings suggested that LPS improved MSC-mediated cardiomyocytes protection by HMGB1/STAT3 signaling.

CaMKII, 'jack of all trades' in inflammation during cardiac ischemia/reperfusion injury

Myocardial infarction and revascularization cause cardiac ischemia/reperfusion (I/R) injury featuring cardiomyocyte death and inflammation. The Ca2+/calmodulin dependent protein kinase II (CaMKII) family are serine/ threonine protein kinases that are involved in I/R injury. CaMKII exists in four different isoforms, α, β, γ, and δ. In the heart, CaMKII-δ is the predominant isoform，with multiple splicing variants, such as δB, δC and δ9. During I/R, elevated intracellular Ca2+ concentrations and reactive oxygen species activate CaMKII. In this review, we summarized the regulation and function of CaMKII in multiple cell types including cardiomyocytes, endothelial cells, and macrophages during I/R. We conclude that CaMKII mediates inflammation in the microenvironment of the myocardium, resulting in cell dysfunction, elevated inflammation, and cell death. However, different CaMKII-δ variants exhibit distinct or even opposite functions. Therefore, reagents/approaches that selectively target specific CaMKII isoforms and variants are needed for evaluating and counteracting the exact role of CaMKII in I/R injury and developing effective treatments against I/R injury.

Serum HMGB1 is a biomarker for acute myocardial infarction with or without heart failure

This study measured serum high mobility group box 1 (HMGB1) levels in patients with acute myocardial infarction (AMI) and/or heart failure (HF) and evaluated their relationship with peripheral inflammatory biomarkers and cardiac biomarkers, which have not been reported before. Of the patients, 55 had AMI without HF (AMI-HF ), 42 had AMI with HF (AMI+HF ), and 60 had HF without AMI (HF-AMI ) compared with 50 healthy controls. Blood samples were collected to assess serum HMGB1 levels and blood test-related inflammatory biomarkers (e.g., erythrocyte sedimentation rate [ESR], hs-CRP, uric acid, and white blood cell count) and cardiac biomarkers (e.g., MYO, cTnI, CKMB, CK, NT-proBNP, LDH, aspartate aminotransferase [AST], and alanine aminotransferase [ALT]). Compared to healthy controls, three groups of patients, especially those with AMI+HF , had significantly higher levels of serum HMGB1. All tested inflammatory biomarkers (except uric acid) were significantly positively correlated with HMGB1 in patients with AMI patients but not in patients with non-AMI. In addition, all tested cardiac biomarkers (except NT-proBNP in AMI-HF ) were significantly higher in patients with AMI than in control individuals. The levels of MYO, cTnI, CKMB, CK, AST, and ALT were not significantly changed in patients with HF-AMI compared to control individuals, but were still much lower than those in patients with AMI (except ALT). In all patients, the levels of NT-proBNP, and cTnI were significantly correlated with HMGB1 levels. Except for MYO, LDH, AST, and ALT, all cardiac biomarkers in AMI-HF and AMI+HF showed a significant correlation with HMGB1. Among risk factors, hypertension, diabetes, previous heart disease, and reduced left ventricular ejection fraction showed a significant correlation with HMGB1 in all disease groups.

Autocrine regulation of tumor cell repopulation by Hsp70-HMGB1 alarmin complex

BACKGROUND

Cancer recurrence is regulated by a variety of factors, among which is the material of dying tumor cells; it is suggested that remaining after anti-cancer therapy tumor cells receive a signal from proteins called damage-associated molecular patterns (DAMPs), one of which is heat shock protein 70 (Hsp70).

METHODS

Two models of tumor repopulation were employed, based on minimal population of cancer cells and application of conditioned medium (CM). To deplete the CMs of Hsp70 affinity chromatography on ATP-agarose and immunoprecipitation were used. Cell proliferation and the dynamics of cell growth were measured using MTT assay and xCELLigence technology; cell growth markers were estimated using qPCR and with the aid of ELISA for prostaglandin E detection. Immunoprecipitation followed by mass-spectrometry was employed to identify Hsp70-binding proteins and protein-protein interaction assays were developed to reveal the above protein complexes.

RESULTS

It was found that CM of dying tumor cells contains tumor regrowth-initiating factors and the removal of one of them, Hsp70, caused a reduction in the relapse-activating capacity. The pull out of Hsp70 alone using ATP-agarose had no effect on repopulation, while the immunodepletion of Hsp70 dramatically reduced its repopulation activity. Using proteomic and immunochemical approaches, we showed that Hsp70 in conditioned medium binds and binds another abundant alarmin, the High Mobility Group B1 (HMGB1) protein; the complex is formed in tumor cells treated with anti-cancer drugs, persists in the cytosol and is further released from dying tumor cells. Recurrence-activating power of Hsp70-HMGB1 complex was proved by the enhanced expression of proliferation markers, Ki67, Aurka and MCM-10 as well as by increase of prostaglandin E production and autophagy activation. Accordingly, dissociating the complex with Hsp70 chaperone inhibitors significantly inhibited the pro-growth effects of the above complex, in both in vitro and in vivo tumor relapse models.

CONCLUSIONS

These data led us to suggest that the abundance of the Hsp70-HMGB1 complex in the extracellular matrix may serve as a novel marker of relapse state in cancer patients, while specific targeting of the complex may be promising in the treatment of cancers with a high risk of recurrence.

Therapeutic targeting of chronic kidney disease-associated DAMPs differentially contributing to vascular pathology

Chronic Kidney Disease (CKD) is associated with markedly increased cardiovascular (CV) morbidity and mortality. Chronic inflammation, a hallmark of both CKD and CV diseases (CVD), is believed to drive this association. Pro-inflammatory endogenous TLR agonists, Damage-Associated Molecular Patterns (DAMPs), have been found elevated in CKD patients' plasma and suggested to promote CVD, however, confirmation of their involvement, the underlying mechanism(s), the extent to which individual DAMPs contribute to vascular pathology in CKD and the evaluation of potential therapeutic strategies, have remained largely undescribed. A multi-TLR inhibitor, soluble TLR2, abrogated chronic vascular inflammatory responses and the increased aortic atherosclerosis-associated gene expression observed in nephropathic mice, without compromising infection clearance. Mechanistically, we confirmed elevation of 4 TLR DAMPs in CKD patients' plasma, namely Hsp70, Hyaluronic acid, HMGB-1 and Calprotectin, which displayed different abilities to promote key cellular responses associated with vascular inflammation and progression of atherosclerosis in a TLR-dependent manner. These included loss of trans-endothelial resistance, enhanced monocyte migration, increased cytokine production, and foam cell formation by macrophages, the latter via cholesterol efflux inhibition. Calprotectin and Hsp70 most consistently affected these functions. Calprotectin was further elevated in CVD-diagnosed CKD patients and strongly correlated with the predictor of CV events CRP. In nephropathic mice, Calprotectin blockade robustly reduced vascular chronic inflammatory responses and pro-atherosclerotic gene expression in the blood and aorta. Taken together, these findings demonstrated the critical extent to which the DAMP-TLR pathway contributes to vascular inflammatory and atherogenic responses in CKD, revealed the mechanistic contribution of specific DAMPs and described two alternatives therapeutic approaches to reduce chronic vascular inflammation and lower CV pathology in CKD.

HMGB family proteins: Potential biomarkers and mechanistic factors in cardiovascular diseases

Cardiovascular disease (CVD) is the most fatal disease that causes sudden death, and inflammation contributes substantially to its occurrence and progression. The prevalence of CVD increases as the population ages, and the pathophysiology is complex. Anti-inflammatory and immunological modulation are the potential methods for CVD prevention and treatment. High-Mobility Group (HMG) chromosomal proteins are one of the most abundant nuclear nonhistone proteins which act as inflammatory mediators in DNA replication, transcription, and repair by producing cytokines and serving as damage-associated molecular patterns in inflammatory responses. The most common and well-studied HMG proteins are those with an HMGB domain, which participate in a variety of biological processes. HMGB1 and HMGB2 were the first members of the HMGB family to be identified and are present in all investigated eukaryotes. Our review is primarily concerned with the involvement of HMGB1 and HMGB2 in CVD. The purpose of this review is to provide a theoretical framework for diagnosing and treating CVD by discussing the structure and function of HMGB1 and HMGB2.

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.

Genetic data visualization using literature text-based neural networks: Examples associated with myocardial infarction

Data visualization is critical to unraveling hidden information from complex and high-dimensional data. Interpretable visualization methods are critical, especially in the biology and medical fields, however, there are limited effective visualization methods for large genetic data. Current visualization methods are limited to lower-dimensional data and their performance suffers if there is missing data. In this study, we propose a literature-based visualization method to reduce high-dimensional data without compromising the dynamics of the single nucleotide polymorphisms (SNP) and textual interpretability. Our method is innovative because it is shown to (1) preserves both global and local structures of SNP while reducing the dimension of the data using literature text representations, and (2) enables interpretable visualizations using textual information. For performance evaluations, we examined the proposed approach to classify various classification categories including race, myocardial infarction event age groups, and sex using several machine learning models on the literature-derived SNP data. We used visualization approaches to examine clustering of data as well as quantitative performance metrics for the classification of the risk factors examined above. Our method outperformed all popular dimensionality reduction and visualization methods for both classification and visualization, and it is robust against missing and higher-dimensional data. Moreover, we found it feasible to incorporate both genetic and other risk information obtained from literature with our method.

HMGB1: a potential new target for tendinopathy treatment

Tendinopathy describes a complex pathology of the tendon characterized by abnormalities in the microstructure, composition, and cellularity of the tendon, leading to pain, limitation of activity and reduced function. Nevertheless, the mechanism of tendinopathy has not been fully elucidated, and the treatment of tendinopathy remains a challenge. High mobility group box 1 (HMGB1), a highly conserved and multifaceted nuclear protein, exerts multiple roles and high functional variability and is involved in many biological and pathological processes. In recent years, several studies have suggested that HMGB1 is associated with tendinopathy and may play a key role in the pathogenesis of tendinopathy. Therefore, this review summarizes the expression and distribution of HMGB1 in tendinopathy, focuses on the roles of HMGB1 and HMGB1-based potential mechanisms involved in tendinopathy, and finally summarizes the findings on HMGB1-based therapeutic approaches in tendinopathy, probably providing new insight into the mechanism and further potential therapeutic targets of tendinopathy.

PCSK9 Inhibition Reduces Depressive like Behavior in CUMS-Exposed Rats: Highlights on HMGB1/RAGE/TLR4 Pathway, NLRP3 Inflammasome Complex and IDO-1

Ample evidence has pointed to a close link between cardiovascular diseases (CVD) and depression. Inflammatory pathways including the high-mobility-group-box-1 protein, receptor-for-advanced-glycation-end-products and toll-like-receptor-4 (HMGB1/RAGE/TLR4) and nucleotide-binding domain (NOD)-like receptor protein 3 (NLRP3) inflammasome pathways are thought to be crucial players in this link. Activation of these pathways ends by releasing of different inflammatory mediators involved in CVD and depression pathophysiology. In the brain, this inflammatory process enhanced indoleamine2,3-dioxygenase-1 (IDO-1) activation with subsequent alteration in kynurenine/tryptophan levels causing depression. Based on the favorable anti-inflammatory effects of Alirocumab, the proprotein-convertase-subtilisin/kexin-type-9 (PCSK9) inhibitor, used in different CVD, this study was designed to investigate its potential antidepressant effect. The behavioral and neurochemical effects of concomitant treatment of Alirocumab at doses of (4, 8 and 16 mg/kg/week subcutaneously) in Wistar rats exposed to chronic unpredictable mild stress (CUMS) for 6 weeks were assayed. Alirocumab prevented CUMS-induced depressive-like-behaviors exhibited in open-field and forced-swimming tests, and hypothalamus-pituitary-adrenal axis hyperactivity (adrenal gland weight and serum corticosterone). Alirocumab prevented CUMS-induced alteration in hippocampal kynurenine/tryptophan levels and pro-inflammatory cytokines tumor-necrosis-factor-alpha, interleukin-1beta (IL-1β), IL-2 and IL-6. Western blot and PCR analysis showed that Alirocumab favorably modulated the HMGB1/RAGE/TLR4 axis, nuclear-factor-kappa-beta, NLRP3 inflammasome complex and IDO-1 in the hippocampus of CUMS rats. These effects were correlated to the level of PCSK9 expression. The behavioral and biochemical findings indicated the potential antidepressant effect of PCSK9 inhibition by Alirocumab.

Structure and Functions of HMGB2 Protein

High-Mobility Group (HMG) chromosomal proteins are the most numerous nuclear non-histone proteins. HMGB domain proteins are the most abundant and well-studied HMG proteins. They are involved in variety of biological processes. HMGB1 and HMGB2 were the first members of HMGB-family to be discovered and are found in all studied eukaryotes. Despite the high degree of homology, HMGB1 and HMGB2 proteins differ from each other both in structure and functions. In contrast to HMGB2, there is a large pool of works devoted to the HMGB1 protein whose structure-function properties have been described in detail in our previous review in 2020. In this review, we attempted to bring together diverse data about the structure and functions of the HMGB2 protein. The review also describes post-translational modifications of the HMGB2 protein and its role in the development of a number of diseases. Particular attention is paid to its interaction with various targets, including DNA and protein partners. The influence of the level of HMGB2 expression on various processes associated with cell differentiation and aging and its ability to mediate the differentiation of embryonic and adult stem cells are also discussed.

Analysis of the influence of pyroptosis-related genes on molecular characteristics in patients with acute myocardial infarction

Pyroptosis is a newly identified mode of programmed cell death, but the potential role in patients with acute myocardial infarction (AMI) remains unclear. In this study, bioinformatics methods were used to identify differentially expressed genes from peripheral blood transcriptome data between normal subjects and patients with AMI which were downloaded by the Gene Expression Omnibus database. Comparing Random Forest (RF) and Support Vector Machine (SVM) training algorithms were used to identify pyroptosis-related genes, predicting patients with AMI by nomogram based on informative genes. Moreover, clustering was used to amplify the feature of pyroptosis, in order to facilitate analysis distinct biological differences. Diversity analysis indicated that a majority of pyroptosis-related genes are expressed at higher levels in patients with AMI. The receiver operating characteristic curves show that the RF model is more responsive than the SVM machine learning model to the pyroptosis characteristics of these patients in vivo. We obtained a column line graph diagnostic model which was developed based on 19 genes established by the RF model. After the consensus clustering algorithm of single sample Gene Set Enrichment Analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) Enrichment Analysis, the results for them found that pyroptosis-related genes mediate the activation of multiple immune cells and many inflammatory pathways in the body. We used RF and SVM algorithms to determine 19 pyroptosis-related genes and evaluate their immunological effects in patients with AMI. We also constructed a series of by nomogram related to pyroptosis-related genes to predict the risk of developing AMI.

MECHANISMS OF CARDIAC DYSFUNCTION IN SEPSIS

ABSTRACT

Studies in animal models of sepsis have elucidated an intricate network of signaling pathways that lead to the dysregulation of myocardial Ca 2+ handling and subsequently to a decrease in cardiac contractile force, in a sex- and model-dependent manner. After challenge with a lethal dose of LPS, male animals show a decrease in cellular Ca 2+ transients (ΔCa i ), with intact myofilament function, whereas female animals show myofilament dysfunction, with intact ΔCa i . Male mice challenged with a low, nonlethal dose of LPS also develop myofilament desensitization, with intact ΔCa i . In the cecal ligation and puncture (CLP) model, the causative mechanisms seem similar to those in the LPS model in male mice and are unknown in female subjects. ΔCa i decrease in male mice is primarily due to redox-dependent inhibition of sarco/endoplasmic reticulum Ca 2+ ATP-ase (SERCA). Reactive oxygen species (ROS) are overproduced by dysregulated mitochondria and the enzymes NADPH/NADH oxidase, cyclooxygenase, and xanthine oxidase. In addition to inhibiting SERCA, ROS amplify cardiomyocyte cytokine production and mitochondrial dysfunction, making the process self-propagating. In contrast, female animals may exhibit a natural redox resilience. Myofilament dysfunction is due to hyperphosphorylation of troponin I, troponin T cleavage by caspase-3, and overproduction of cGMP by NO-activated soluble guanylate cyclase. Depleted, dysfunctional, or uncoupled mitochondria likely synthesize less ATP in both sexes, but the role of energy deficit is not clear. NO produced by NO synthase (NOS)-3 and mitochondrial NOSs, protein kinases and phosphatases, the processes of autophagy and sarco/endoplasmic reticulum stress, and β-adrenergic insensitivity may also play currently uncertain roles.

Structural Characteristics of High-Mobility Group Proteins HMGB1 and HMGB2 and Their Interaction with DNA

Non-histone nuclear proteins HMGB1 and HMGB2 (High Mobility Group) are involved in many biological processes, such as replication, transcription, and repair. The HMGB1 and HMGB2 proteins consist of a short N-terminal region, two DNA-binding domains, A and B, and a C-terminal sequence of glutamic and aspartic acids. In this work, the structural organization of calf thymus HMGB1 and HMGB2 proteins and their complexes with DNA were studied using UV circular dichroism (CD) spectroscopy. Post-translational modifications (PTM) of HMGB1 and HMGB2 proteins were determined with MALDI mass spectrometry. We have shown that despite the similar primary structures of the HMGB1 and HMGB2 proteins, their post-translational modifications (PTMs) demonstrate quite different patterns. The HMGB1 PTMs are located predominantly in the DNA-binding A-domain and linker region connecting the A and B domains. On the contrary, HMGB2 PTMs are found mostly in the B-domain and within the linker region. It was also shown that, despite the high degree of homology between HMGB1 and HMGB2, the secondary structure of these proteins is also slightly different. We believe that the revealed structural properties might determine the difference in the functioning of the HMGB1 and HMGB2 as well as their protein partners.

CARDIOMYOCYTE REPROGRAMMING IN ANIMAL MODELS OF SEPTIC SHOCK

ABSTRACT

Cardiomyocyte reprogramming plays a pivotal role in sepsis-induced cardiomyopathy through the induction or overexpression of several factors and enzymes, ultimately leading to the characteristic decrease in cardiac contractility. The initial trigger is the binding of LPS to TLR-2, -3, -4, and -9 and of proinflammatory cytokines, such as TNF, IL-1, and IL-6, to their respective receptors. This induces the nuclear translocation of nuclear factors, such as NF-κB, via activation of MyD88, TRIF, IRAK, and MAPKs. Among the latter, ROS- and estrogen-dependent p38 and ERK 1/2 are proinflammatory, whereas JNK may play antagonistic, anti-inflammatory roles. Nuclear factors induce the synthesis of cytokines, which can amplify the inflammatory signal in a paracrine fashion, and of several effector enzymes, such as NOS-2, NOX-1, and others, which are ultimately responsible for the degradation of cardiomyocyte contractility. In parallel, the downregulation of enzymes involved in oxidative phosphorylation causes metabolic reprogramming, followed by a decrease in ATP production and the release of fragmented mitochondrial DNA, which may augment the process in a positive feedback loop. Other mediators, such as NO, ROS, the enzymes PI3K and Akt, and adrenergic stimulation may play regulatory roles, but not all signaling pathways that mediate cardiac dysfunction of sepsis do that by regulating reprogramming. Transcription may be globally modulated by miRs, which exert protective or amplifying effects. For all these mechanisms, differentiating between modulation of cardiomyocyte reprogramming versus systemic inflammation has been an ongoing but worthwhile experimental challenge.

The Effect of Necrosis Inhibitor on Dextran Sulfate Sodium Induced Chronic Colitis Model in Mice

Uncontrolled chronic inflammation and necrosis is characteristic of inflammatory bowel disease (IBD). This study aimed to investigate the effect of necrosis inhibitor (NI, NecroX-7) on a dextran sulfate sodium (DSS) induced chronic colitis model of mice. DSS was administered on days 1-5, and the NI was administered intraperitoneally (3 mg/kg, 30 mg/kg) on days 1, 3, and 5 as well as every other day during the first five days of a three-week cycle. Three cycles of administration were performed. Colitis was evaluated based on the disease activity index (DAI) score, colon length, and histological score. Reverse transcription polymerase chain reaction testing, the Western blot assay, and immunohistochemical staining were performed to determine inflammatory cytokine levels. The NI reduced body weight change and the DAI score. Colon length and the histological score were longer and lower in the NI-treated groups, respectively. The NI decreased the expression of pro-inflammatory cytokines, particularly in tumor necrosis factor alpha (TNF-α) and phosphorylated nuclear factor kappa B (p-NF-κB). Immunohistochemical staining revealed decreased inducible nitric oxide synthase (iNOS) and high mobility group box 1 (HMGB1) levels. Overall, the NI improved DSS induced chronic colitis by attenuating the mRNA expression of pro-inflammatory cytokines such as TNF-α. Therefore, NI use is a potential, novel treatment approach for IBD.

Assessment of the soluble proteins HMGB1, CD40L and CD62P during various platelet preparation processes and the storage of platelet concentrates: The BEST collaborative study

BACKGROUND

Structural and biochemical changes in stored platelets are influenced by collection and processing methods. This international study investigates the effects of platelet (PLT) processing and storage conditions on HMGB1, sCD40L, and sCD62P protein levels in platelet concentrate supernatants (PCs).

STUDY DESIGN/METHODS

PC supernatants (n = 3748) were collected by each international centre using identical centrifugation methods (n = 9) and tested centrally using the ELISA/Luminex platform. Apheresis versus the buffy coat (BC-PC) method, plasma storage versus PAS and RT storage versus cold (4°C) were investigated. We focused on PC preparation collecting samples during early (RT: day 1-3; cold: day 1-5) and late (RT: day 4-7; cold: day 7-10) storage time points.

RESULTS

HMGB1, sCD40L, and sCD62P concentrations were similar during early storage periods, regardless of storage solution (BC-PC plasma and BC-PC PAS-E) or temperature. During storage and without PAS, sCD40L and CD62P in BC-PC supernatants increased significantly (+33% and +41%, respectively) depending on storage temperature (22 vs. 4°C). However, without PAS-E, levels decreased significantly (-31% and -20%, respectively), depending on storage temperature (22 vs. 4°C). Contrastingly, the processing method appeared to have greater impact on HMGB1 release versus storage duration. These data highlight increases in these parameters during storage and differences between preparation methods and storage temperatures.

CONCLUSIONS

The HMGB1 release mechanism/intracellular pathways appear to differ from sCD62P and sCD40L. The extent to which these differences affect patient outcomes, particularly post-transfusion platelet increment and adverse events, warrants further investigation in clinical trials with various therapeutic indications.

The Multiple Functions of Melatonin: Applications in the Military Setting

The aim of this review is to provide the reader with a general overview on the rationale for the use of melatonin by military personnel. This is a technique that is being increasingly employed to manage growing psycho-physical loads. In this context, melatonin, a pleotropic and regulatory molecule, has a potential preventive and therapeutic role in maintaining the operational efficiency of military personnel. In battlefield conditions in particular, the time to treatment after an injury is often a major issue since the injured may not have immediate access to medical care. Any drug that would help to stabilize a wounded individual, especially if it can be immediately administered (e.g., per os) and has a very high safety profile over a large range of doses (as melatonin does) would be an important asset to reduce morbidity and mortality. Melatonin may also play a role in the oscillatory synchronization of the neuro-cardio-respiratory systems and, through its epigenetic action, poses the possibility of restoring the main oscillatory waves of the cardiovascular system, such as the Mayer wave and RSA (respiratory sinus arrhythmia), which, in physiological conditions, result in the oscillation of the heartbeat in synchrony with the breath. In the future, this could be a very promising field of investigation.

Damage-associated molecular patterns in vitiligo: igniter fuse from oxidative stress to melanocyte loss

OBJECTIVES

The pathogenesis of vitiligo remains unclear. In this review, we comprehensively describe the role of damage associated molecular patterns (DAMPs) during vitiligo pathogenesis.

METHODS

Published papers on vitiligo, oxidative stress and DAMPs were collected and reviewed via database searching on PubMed, MEDLINE and Embase, etc.

RESULTS

Oxidative stress may be an important inducer of vitiligo. At high oxidative stress levels, damage-associated molecular patterns (DAMPs) are released from keratinocytes or melanocytes in the skin and induce downstream immune responses during vitiligo. Treatment regimens targeting DAMPs can effectively improve disease severity.

DISCUSSION

DAMPs play key roles in initiating host defenses against danger signals, deteriorating the condition of vitiligo. DAMP levels in serum and skin may be used as biomarkers to indicate vitiligo activity and prognosis. Targeted therapies, incorporating HMGB1, Hsp70, and IL-15 could significantly improve disease etiology. Thus, novel strategies could be identified for vitiligo treatment by targeting DAMPs.

The Association between High Mobility Group Box 1 and Stroke-Associated Pneumonia in Acute Ischemic Stroke Patients

Objective: This study aimed to investigate the association between high-mobility-group box 1 (HMGB1) and stroke-associated pneumonia (SAP) in acute ischemic stroke (AIS) patients. Methods: AIS patients were enrolled in two centers. The serum samples were collected within the first 24 h after admission, and HMGB1 levels were measured by enzyme-linked immunosorbent assay. Logistic regression models were used to calculate the odds ratio (OR) and 95% confidence interval (95% CI) of SAP for HMGB1 concentrations. Restricted cubic splines (RCS) were performed to explore the shapes of the association between HMGB1 concentrations and SAP. Results: From January 2022 to May 2022, a total of 420 AIS patients were enrolled. Ninety-six (22.9%) patients develop SAP. The levels of HMGB1 in the SAP group were higher than those in the non-SAP group (p < 0.001). Using the first quartile of HMGB1 group as a reference, patients in the fourth quartile of HMGB1 group had the highest likelihood of experiencing SAP in the unadjusted model (OR = 3.687; 95% CI: 1.851−7.344), age- and sex-adjusted model (OR = 3.511; 95% CI: 1.725−7.147), and multivariable-adjusted model (OR = 2.701; 95% CI: 1.045−6.981). HMGB1 was also independently associated with SAP as a continuous variable in the unadjusted model (OR = 1.132; 95% CI: 1.069−1.199), age- and sex-adjusted model (OR = 1.131; 95% CI: 1.066−1.200), and multivariable-adjusted model (OR = 1.096; 95% CI: 1.011−1.188). RCS showed a linear association between HMGB1 and SAP (p for linear trend = 0.008) Conclusions: HMGB1 might be able to act as a potential biomarker of SAP in AIS patients.

Correlation of Delayed Onset Muscle Soreness and Inflammation Post-exercise Induced Muscle Damage

BACKGROUND: Delayed Onset Muscle Soreness (DOMS) is a common injury resulting from abnormal intensive training in athletes, mainly the result of training involving eccentric contractions. AIM: The aim of this study was to determine the correlation between the incidence of DOMS and HMGB1 as a marker of the occurrence of inflammation post Exercise Induces Muscle Damaged. METHOD: 28 male recreational students of Sports Science Department, Universitas Negeri Surabaya who met all inclusion and exclusion criteria participated in this study. Participants completed a muscle damaging exercise which consists of a 10x10 drop jump (DRP) and a bout of 40×15 m sprints with a 5 m deceleration zone (SPR) to obtain a muscle damage effect. In this study, the stretching in the exercise session was not given, this was done to get the DOMS effect after exercise. DOMS and HMGB1 was carry out 1 hour before the exercise, 12 hours after the exercise, 24 hours after the exercise and 48 hours after the exercise. RESULT: The result showed that there was a significant correlation (r=0.935, p<0.05) between DOMS and HMGB1 as a predictor of inflammation. The participants that were given EIMD eccentric exercise (DRP and SPR) showed the occurrence of DOMS and increasing of HMGB1. The result also showed that there was a correlation between DOMS and HMGB1. CONCLUSION: This study concluded that there was a correlation between DOMS and HMGB1 as a marker of inflammation as the result of the eccentric exercise of the exercise Induced Muscle Damage (EIMD).

Alpha-lipoic acid impedes myocardial ischemia-reperfusion injury, myocardial apoptosis, and oxidative stress by regulating HMGB1 expression

BACKGROUND

Inflammation, oxidative stress, and apoptosis contribute to myocardial ischemia/reperfusion injury (I/RI). Alpha-lipoic acid (ALA) plays a critical role in I/RI by impeding apoptosis and inflammation. Here, we aimed to explore the underlying mechanisms of ALA after I/RI.

METHODS

The left anterior descending coronary artery (LAD) was ligated, and H9c2 cells were exposed to hypoxia/reoxygenation (H/R) to establish an I/RI model. Prior to this, H9c2 cells and rats were treated using an appropriate amount of ALA. The cardiac function, inflammatory factors, and myocardial pathology were assessed in vitro. We detected cell viability, apoptosis, and oxidative stress-related factors in vivo. Moreover, proteins of the HMGB1/TLR4/NF-κB signaling pathway were detected both in vivo and in vitro.

RESULTS

We observed that ALA increased cell viability in vitro and decreased apoptosis in vitro and in vivo. ALA inhibited reactive oxygen species production, decreased malondialdehyde, and increased superoxide dismutase activity to resist oxidative stress in vitro. ALA also reduced the expression of inflammatory cytokines (IL-6, IL-1β, and TNF-α) in vivo. ALA also suppressed the levels of the apoptotic protein, Bax, and increased the expression of the anti-apoptotic protein Bcl-2, in vitro and in vivo. Moreover, we observed that ALA significantly inhibited the cytoplasmic localization of HMGB1, which might attenuate MI/RI or H/R via HMGB1/TLR4/NF-κB pathway.

CONCLUSION

ALA regulates HMGB1 translocation and attenuates I/R via the HMGB1/TLR4/NF-κB signaling pathway, thus impeding apoptosis, oxidation, and inflammation, and might be a potential target for myocardial ischemia/reperfusion injury.

Serum microRNAs are key predictors of long-term heart failure and cardiovascular death after myocardial infarction

BACKGROUND

Patients with acute myocardial infarction (MI) are at high risk of upcoming events, in particular heart failure (HF), but reliable stratification methods are lacking. Our goal was to evaluate the potential role of circulating miRNAs as prognostic biomarkers in patients presenting with MI.

METHODS AND RESULTS

We conducted a prospective study among 311 consecutive patients hospitalized with MI (65% ST-segment elevation MI & median age of 55 years) with long-term follow-up. An initial screening was conducted to select candidate miRNAs, with subsequent study of 14 candidate miRNAs. The primary outcome was the composite of hospital admission for HF or cardiovascular death. During a mean follow-up of 2.1 years miR-21-5p, miR-23a-3p, miR27b-3p, miR-122-5p, miR210-3p, and miR-221-3p reliably predicted the primary outcome. Multivariate Cox regression analyses highlighted that miR-210-3p [hazard ratio (HR) 2.65 per 1 SD increase, P < 0.001], miR-23a-3p (HR 2.11 per 1 SD increase, P < 0.001), and miR-221-3p (HR 2.03 per 1 SD increase, P < 0.001) were able to accurately predict the primary outcome, as well as cardiovascular death, HF hospitalizations, and long-term New York Heart Association (NYHA) functional class. These three miRNAs clearly improved the performance of multivariate clinical models: ΔC-statistic = 0.10 [95% confidence interval (CI), 0.03-0.17], continuous net reclassification index = 34.8% (95%CI, 5.8-57.4%), and integrated discrimination improvement (P < 0.001).

CONCLUSIONS

This is the largest study evaluating the prognostic value of circulating miRNAs for HF-related events among patients with MI. We show that several miRNAs predict HF hospitalizations, cardiovascular mortality, and poor long-term NYHA status and improve current risk prediction methods.

HMGB1 is a critical molecule in the pathogenesis of Gram-negative sepsis

Gram-negative sepsis is a severe clinical syndrome associated with significant morbidity and mortality. Lipopolysaccharide (LPS), expressed on Gram-negative bacteria, is a potent pro-inflammatory toxin that induces inflammation and coagulation via two separate receptor systems. One is Toll-like receptor 4 (TLR4), expressed on cell surfaces and in endosomes, and the other is the cytosolic receptor caspase-11 (caspases-4 and -5 in humans). Extracellular LPS binds to high mobility group box 1 (HMGB1) protein, a cytokine-like molecule. The HMGB1-LPS complex is transported via receptor for advanced glycated end products (RAGE)-endocytosis to the endolysosomal system to reach the cytosolic LPS receptor caspase-11 to induce HMGB1 release, inflammation, and coagulation that may cause multi-organ failure. The insight that LPS needs HMGB1 assistance to generate severe inflammation has led to successful therapeutic results in preclinical Gram-negative sepsis studies targeting HMGB1. However, to date, no clinical studies have been performed based on this strategy. HMGB1 is also actively released by peripheral sensory nerves and this mechanism is fundamental for the initiation and propagation of inflammation during tissue injury. Homeostasis is achieved when other neurons actively restrict the inflammatory response via monitoring by the central nervous system and the vagus nerve through the cholinergic anti-inflammatory pathway. The neuronal control in Gram-negative sepsis needs further studies since a deeper understanding of the interplay between HMGB1 and acetylcholine may have beneficial therapeutic implications. Herein, we review the synergistic overlapping mechanisms of LPS and HMGB1 and discuss future treatment opportunities in Gram-negative sepsis.

Oxidative Stress in Ageing and Chronic Degenerative Pathologies: Molecular Mechanisms Involved in Counteracting Oxidative Stress and Chronic Inflammation

Ageing and chronic degenerative pathologies demonstrate the shared characteristics of high bioavailability of reactive oxygen species (ROS) and oxidative stress, chronic/persistent inflammation, glycation, and mitochondrial abnormalities. Excessive ROS production results in nucleic acid and protein destruction, thereby altering the cellular structure and functional outcome. To stabilise increased ROS production and modulate oxidative stress, the human body produces antioxidants, “free radical scavengers”, that inhibit or delay cell damage. Reinforcing the antioxidant defence system and/or counteracting the deleterious repercussions of immoderate reactive oxygen and nitrogen species (RONS) is critical and may curb the progression of ageing and chronic degenerative syndromes. Various therapeutic methods for ROS and oxidative stress reduction have been developed. However, scientific investigations are required to assess their efficacy. In this review, we summarise the interconnected mechanism of oxidative stress and chronic inflammation that contributes to ageing and chronic degenerative pathologies, including neurodegenerative diseases, such as Alzheimer’s disease (AD) and Parkinson’s disease (PD), cardiovascular diseases CVD, diabetes mellitus (DM), and chronic kidney disease (CKD). We also highlight potential counteractive measures to combat ageing and chronic degenerative diseases.

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.

Glycyrrhiza uralensis Fisch. and its active components mitigate Semen Strychni-induced neurotoxicity through regulating high mobility group box 1 (HMGB1) translocation

Semen Strychni has long been used for the treatment of rheumatoid arthritis, facioplegia and myasthenia gravis due to its anti-inflammation and anti-nociceptive properties in China. However, the fatal neurotoxicity of Semen Strychni has limited its wider clinical application. To investigate the acute toxicity induced by Semen Strychni and the detoxification of liquorice, we evaluated inflammation, oxidative stress and the translocation of high mobility group box 1 (HMGB1) in rats. As a result, there were obvious oxidative stress and inflammation in hippocampus after the Semen Strychni extracts (STR) treatment in rats. Liquorice extracts (LE) and its three active monomers - glycyrrhizic acid (GA), liquiritigenin (LIQ), isoliquiritigenin (ISL) showed the potential for mitigating STR-induced neurotoxicity. HMGB1 levels in cytoplasm and serum and the levels of two downstream receptors RAGE and TLR4 were significantly increased after STR treatment. Through using LE and the monomers, the nucleocytoplasmic transport and release of HMGB1 were inhibited. In addition, the binding between HMGB1 and TLR4 was weakened in detoxification groups comparing with the STR group. Taken together, these findings indicated that liquorice and its active components alleviated acute neurotoxicity induced by Semen Strychni partly via HMGB1-related pathway.

HMGB1 in macrophage nucleus protects against pressure overload induced cardiac remodeling via regulation of macrophage differentiation and inflammatory response

Pressure overload induced cardiac remodeling is associated with a complex spectrum of pathophysiological mechanisms. As inflammatory cells, macrophages maintain a critical position in mechanical stress-induced myocardial remodeling. HMGB1 is a highly conserved, ubiquitous protein in various types of cells whose biological roles are closely dependent on subcellular sites. However, whether HMGB1 expressed in macrophages performs the protective or pathological responses in cardiac remodeling is unknown. In this study, we generated the myeloid-specific HMGB1 knockout mice and detected the effects of macrophage HMGB1 in response to pathophysiological stress. Our data showed HMGB1 in macrophages played a protective role against the pressure overload induced cardiac pathophysiology. The deletion of HMGB1 in macrophages gains more differentiation of M1-type pro-inflammatory macrophage during the mechanical stress-induced myocardial remodeling, thereby aggravating the inflammatory response in whole heart, resulting in accelerated deterioration of cardiac function. Moreover, in vitro data also validated HMGB1 got involved in the process of macrophage polarization. Macrophages without HMGB1 are more inclined to differentiate into M1 during the stretch process. In summary, the present results indicated that loss of HMGB1 in macrophages can exacerbate heart failure through increased differentiation of pro-inflammatory macrophages and enhanced inflammatory response.

Doxorubicin induced immune abnormalities and inflammatory responses via HMGB1, HIF1-α and VEGF pathway in progressive of cardiovascular damage

Background

Doxorubicin (DOX) is a commonly used treatment for cancer and the mechanism of DOX-induced cardiomyocyte damage in cardiovascular disease is not fully understood. High-mobility group box 1 (HMGB1), strong induce proinflammatory cytokines via damage associated molecular pattern (DAMP) which its interaction with the receptor of advanced glycation end products (RAGE), that affect cytokine release, and angiogenesis via the role of HMBG1, HIF-1α and VEGF as an important regulator in these cardiac failure processes. Hypoxia-inducible factor-1α (HIF-1α) is plays an important role in the cellular response to systemic oxygen levels of cells and VEGF is an angiogenic factor and can stimulate cellular responses on the surface of endothelial cells will be described

Objective

The aim of this article is to comprehensively review the role of HMGB1, HIF-1α, and VEGF in DOX-induced Cardiovascular Disease and its molecular mechanisms.

Methods

The data in this study were collect by search the keyword combinations of medical subject headings (MeSH) of “HMGB1”, “HIF-1 α”, “VEGF”, “DOX” and “Cardiovascular disease” and relevant reference lists were manually searched in PubMed, EMBASE and Scopus database. All relevant articles in data base above were included and narratively discussed in this review article.

Results

Several articles were revealed that molecular mechanisms of the DOX in cardiomyocyte damage and related to HMGB1, HIF-1α and VEGF and may potential treatment and prevention to cardiovascular disease in DOX intervention.

Conclusion

HMGB1, HIF-1α and VEGF has a pivotal regulator in DOX-induce cardiomyocyte damage and predominantly acts through different pathways. The role of HMGB1 in DOX-induced myocardial damage suggests that HMGB1 is a mediator of DOX-induced damage. In addition, DOX can inhibit HIF-1α activity where DOX can decrease HIF-1α expression and HIF-1α is also responsible for upregulation of several angiogenic factors, including VEGF. VEGF plays an important role in angiogenesis and anti-angiogenesis both in vitro and in vivo and reduces the side effects of DOX markedly. In addition, the administration of anti-angiogenesis will show an inhibitory effect on angiogenesis mediated by the VEGF signaling pathway and triggered by DOX in cells.

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The effect of Doxorubicin (DOX) induced cardiovascular damage via several pathways.

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Cardiovascular damage can involve HMGB1, HIF-1α, and VEGF.

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HMGB1, HIF-1α, and VEGF as a pivotal regulator in DOX-induce cardiomyocyte damage.

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HMGB1, HIF-1α, and VEGF in cardiovascular diseases will be predominantly acting through different pathways.

PDGFR-β signaling mediates HMGB1 release in mechanically stressed vascular smooth muscle cells

Mechanically stressed vascular smooth muscle cells (VSMCs) have potential roles in the development of vascular complications. However, the underlying mechanisms are unclear. Using VSMCs cultured from rat thoracic aorta explants, we investigated the effects of mechanical stretch (MS) on the cellular secretion of high mobility group box 1 (HMGB1), a major damage-associated molecular pattern that mediates vascular complications in stressed vasculature. Enzyme-linked immunosorbent assay (ELISA) demonstrated an increase in the secretion of HMGB1 in VSMCs stimulated with MS (0–3% strain, 60 cycles/min), and this secretion was markedly and time-dependently increased at 3% MS. The increased secretion of HMGB1 at 3% MS was accompanied by an increased cytosolic translocation of nuclear HMGB1; the acetylated and phosphorylated forms of this protein were significantly increased. Among various inhibitors of membrane receptors mediating mechanical signals, AG1295 (a platelet-derived growth factor receptor (PDGFR) inhibitor) attenuated MS-induced HMGB1 secretion. Inhibitors of other receptors, including epidermal growth factor, insulin-like growth factor, and fibroblast growth factor receptors, did not inhibit this secretion. Additionally, MS-induced HMGB1 secretion was markedly attenuated in PDGFR-β-deficient cells but not in cells transfected with PDGFR-α siRNA. Likewise, PDGF-DD, but not PDGF-AA, directly increased HMGB1 secretion in VSMCs, indicating a pivotal role of PDGFR-β signaling in the secretion of this protein in VSMCs. Thus, targeting PDGFR-β-mediated secretion of HMGB1 in VSMCs might be a promising therapeutic strategy for vascular complications associated with hypertension.

High Mobility Group Box 1: Biological Functions and Relevance in Oxidative Stress Related Chronic Diseases

In the early 1970s, a group of non-histone nuclear proteins with high electrophoretic mobility was discovered and named high-mobility group (HMG) proteins. High-mobility group box 1 (HMGB1) is the most studied HMG protein that detects and coordinates cellular stress response. The biological function of HMGB1 depends on its subcellular localization and expression. It plays a critical role in the nucleus and cytoplasm as DNA chaperone, chromosome gatekeeper, autophagy maintainer, and protector from apoptotic cell death. HMGB1 also functions as an extracellular alarmin acting as a damage-associated molecular pattern molecule (DAMP). Recent findings describe HMGB1 as a sophisticated signal of danger, with a pleiotropic function, which is useful as a clinical biomarker for several disorders. HMGB1 has emerged as a mediator in acute and chronic inflammation. Furthermore, HMGB1 targeting can induce beneficial effects on oxidative stress related diseases. This review focus on HMGB1 redox status, localization, mechanisms of release, binding with receptors, and its activities in different oxidative stress-related chronic diseases. Since a growing number of reports show the key role of HMGB1 in socially relevant pathological conditions, to our knowledge, for the first time, here we analyze the scientific literature, evaluating the number of publications focusing on HMGB1 in humans and animal models, per year, from 2006 to 2021 and the number of records published, yearly, per disease and category (studies on humans and animal models).

Correlation of HMGB1, PON-1, MCP-1, and Periodontal P. gingivalis with Amniotic Fluid Fecal Dye

Background. This paper aims to investigate the correlation between high mobility group protein-1 (HMG-b1), antioxidant enzyme-1 (paraoxon-1, PON-1), monocyte chemoattractant protein-1 (monocyte chemoattractant protein-1, MCP-1), P. gingivalis, and MSAF. Materials and Methods. The total sample size comprised of 73 cases in both groups. These patients were further subdivided into 2 groups: the MSAF group and the control group. 38 women were in the MSAF group and 35 women with term amniotic fluid serum were in the control group. The MSAF group was selected as a full-term singleton amniotic fluid fecal infection group. Clinical data were collected, and specimens were collected. Fecal staining of amniotic fluid and full-term amniotic fluid removes the placenta and umbilical cord blood. The expression of HMGB1 in the placenta was observed by immune-histochemical staining of MSAF and control groups. The content of PON-1 in cord blood was determined by ELISA. Results. Correlation between maternal and neonatal clinical data and MSAF was done; MSAF group mean gestational age was 41.38 ± 1.40 weeks; control group mean gestational age was 39.20 ± 1.24 weeks. This study found no correlation between the birth weight, maternal age, sex, first/transmaternal, hyperthyroidism, hypothyroidism, and anemia between the MSAF and control group with nonsignificant P value ( $P>0.05$ ). However, the fatal age, gestational diabetes, gestational hypertension, umbilical cord abnormalities, placental abnormalities, and neonatal asphyxia factors were statistically different with a significant P value of <0.05 between both groups. HMGB1 and Periodontal P. gingivalis are mostly expressed in placental trophoblast, vascular endothelial cells, and amniotic epithelial and interstitial cells. After HE staining of 72 placentas by HE in MSAF and control, 6 had acute chorioamnionitis (5.1 control), 32 had chronic (23.9), 35 had abnormal placentas, and three in MSAF had chorionic columnar metaplasia. In immune-histochemistry experiments, the HMGB1 expression intensity of placental tissue was higher in the MSAF group ( $P<0.05$ ); however, the level of PON-1 was lower in the MSAF group as compared to the controls ( $P<0.05$ ). Conclusions. Gestational age and placental abnormalities are clinical high-risk factors for MSAF. HMGB1, PON-1, MCP-1, and Periodontal P. gingivalis may be involved in the development of MSAF, suggesting an oxidative/antioxidant imbalance with inflammation, and may be one of the mechanisms for MSAF development.

The mechanism of HMGB1 secretion and release

High mobility group box 1 (HMGB1) is a nonhistone nuclear protein that has multiple functions according to its subcellular location. In the nucleus, HMGB1 is a DNA chaperone that maintains the structure and function of chromosomes. In the cytoplasm, HMGB1 can promote autophagy by binding to BECN1 protein. After its active secretion or passive release, extracellular HMGB1 usually acts as a damage-associated molecular pattern (DAMP) molecule, regulating inflammation and immune responses through different receptors or direct uptake. The secretion and release of HMGB1 is fine-tuned by a variety of factors, including its posttranslational modification (e.g., acetylation, ADP-ribosylation, phosphorylation, and methylation) and the molecular machinery of cell death (e.g., apoptosis, pyroptosis, necroptosis, alkaliptosis, and ferroptosis). In this minireview, we introduce the basic structure and function of HMGB1 and focus on the regulatory mechanism of HMGB1 secretion and release. Understanding these topics may help us develop new HMGB1-targeted drugs for various conditions, especially inflammatory diseases and tissue damage.

A nuclear protein that gets released after cell death or is actively secreted by immune cells offers a promising therapeutic target for treating diseases linked to excessive inflammation. Daolin Tang from the University of Texas Southwestern Medical Center in Dallas, USA, and colleagues review how cellular stresses can trigger the accumulation of HMGB1, a type of alarm signal protein that promotes the recruitment and activation of inflammation-promoting immune cells. The researchers discuss various mechanisms that drive both passive and active release of HMGB1 into the space around cells. These processes, which include enzymatic modifications of the HMGB1 protein, cell–cell interactions and molecular pathways of cell death, could be targeted by drugs to lessen tissue damage and inflammatory disease caused by HMGB1-induced immune responses

HMGB1-Mediated Activation of the Inflammatory-Reparative Response Following Myocardial Infarction

Different cell types belonging to the innate and adaptive immune system play mutually non-exclusive roles during the different phases of the inflammatory-reparative response that occurs following myocardial infarction. A timely and finely regulation of their action is fundamental for the process to properly proceed. The high-mobility group box 1 (HMGB1), a highly conserved nuclear protein that in the extracellular space can act as a damage-associated molecular pattern (DAMP) involved in a large variety of different processes, such as inflammation, migration, invasion, proliferation, differentiation, and tissue regeneration, has recently emerged as a possible regulator of the activity of different immune cell types in the distinct phases of the inflammatory reparative process. Moreover, by activating endogenous stem cells, inducing endothelial cells, and by modulating cardiac fibroblast activity, HMGB1 could represent a master regulator of the inflammatory and reparative responses following MI. In this review, we will provide an overview of cellular effectors involved in these processes and how HMGB1 intervenes in regulating each of them. Moreover, we will summarize HMGB1 roles in regulating other cell types that are involved in the different phases of the inflammatory-reparative response, discussing how its redox status could affect its activity.

Maslinic Acid Attenuates Ischemia/Reperfusion Injury-Induced Myocardial Inflammation and Apoptosis by Regulating HMGB1-TLR4 Axis

Aims: The inflammatory response and apoptosis are the major pathological features of myocardial ischemia/reperfusion injury (MI/RI). Maslinic acid (MA), a natural pentacyclic triterpene with various bioactivities, plays critical roles in the multiple cellular biological processes, but its protective effects on the pathophysiological processes of MI/RI have not been extensively investigated. Our study aimed to determine whether MA treatment alleviate ischemia/reperfusion (I/R)-induced myocardial inflammation and apoptosis both in vitro and in vivo, and further reveal the underlying mechanisms. Methods and results: An MI/RI rat model was successfully established by ligating the left anterior descending coronary artery and H9c2 cells were exposed to hypoxia/reoxygenation (H/R) to mimic I/R injury. In addition, prior to H/R stimulation or myocardial I/R operation, the H9c2 cells or rats were treated with varying concentrations of MA or vehicle for 24 h and two consecutive days, respectively. In this study, our results showed that MA could obviously increase the cell viability and decrease the cardiac enzymes release after H/R in vitro. MA could significantly improve the H/R-induced cardiomyocyte injury and I/R-induced myocardial injury in a dose-dependent manner. Moreover, MA suppressed the expression of inflammatory cytokines (tumor necrosis factor alpha [TNF-α, interleukin-1β [IL-1β and interleukin-6 [IL-6]) and the expressions of apoptosis-related proteins (cleaved caspase-3 and Bax) as well as increased the levels of anti-apoptotic protein Bcl-2 expression both in vitro and in vivo. Mechanistically, MA significantly inhibited nuclear translocation of nuclear factor-κB (NF-κB) p65 after H/R via regulating high mobility group box 1 (HMGB1)/toll-like receptor 4 (TLR4) axis. Conclusion: Taken together, MA treatment may alleviate MI/RI by suppressing both the inflammation and apoptosis in a dose-dependent manner, and the cardioprotective effect of MA may be partly attributable to the inactivation of HMGB1/TLR4/NF-κB pathway, which offers a new therapeutic strategy for MI/RI.

Inhibition of HMGB1 alleviates myocardial ischemia/reperfusion injury in diabetic mice via suppressing autophagy

BACKGROUND

Diabetes aggravates myocardial ischemia/reperfusion (I/R) injury (MI/RI). The association between high mobility group box 1 protein (HMGB1) and autophagy in diabetic MI/RI remains unknown. Therefore, we investigated whether inhibiting HMGB1 can regulate autophagy in diabetic mice (DM) after I/R injury.

METHODS

I/R models of C57BL/KsJ mice and db/db mice were established. Histological changes, infarct size (IS), HMGB1 protein, and autophagy-related proteins were detected after 24h of reperfusion. In DM treatment groups, anti-HMGB1 antibody (H-Ig) was injected via tail vein after reperfusion for 15min, and the above-mentioned experimental methods were performed at the end of reperfusion.

RESULTS

Compared with the I/R group, the pathological myocardial damage and IS were significantly increased in the I/R (DM) group. Additionally, the levels of HMGB1, Beclin1, and LC3II/LC3I ratio were remarkably higher in the I/R (DM) group than those in the I/R group, while p62 level was lower. In the H-Ig (DM) group, injection of H-Ig significantly reduced the IS, as well as alleviated pathological myocardial damage. Moreover, Beclin1, LC3II/LC3I ratio, and p62 levels were notably reversed after this treatment.

CONCLUSIONS

I/R-induced myocardium was aggravated by diabetes, which may be related to increased release of HMGB1 and activated autophagy. Inhibition of HMGB1 alleviates diabetic MIRI which was associated with reduced autophagy.

Cerebral derailment after myocardial infarct: mechanisms and effects of the signaling from the ischemic heart to brain

Myocardial infarction (MI) is the leading cause of death among ischemic heart diseases and is associated with several long-term cardiovascular complications, such as angina, re-infarction, arrhythmias, and heart failure. However, MI is frequently accompanied by non-cardiovascular multiple comorbidities, including brain disorders such as stroke, anxiety, depression, and cognitive impairment. Accumulating experimental and clinical evidence suggests a causal relationship between MI and stroke, but the precise underlying mechanisms have not yet been elucidated. Indeed, the risk of stroke remains a current challenge in patients with MI, in spite of the improvement of medical treatment among this patient population has reduced the risk of stroke. In this review, the effects of the signaling from the ischemic heart to the brain, such as neuroinflammation, neuronal apoptosis, and neurogenesis, and the possible actors mediating these effects, such as systemic inflammation, immunoresponse, extracellular vesicles, and microRNAs, are discussed.

MiR-125b enhances autophagic flux to improve septic cardiomyopathy via targeting STAT3/HMGB1

We explore the role of miR-125b in septic cardiomyopathy, focusing on miR-125b/STAT3/HMGB1 axis. CLP mouse model and LPS-stimulated primary rat cardiomyocytes (CMs) and H9C2 cell were used as in vivo and in vitro models of septic cardiomyopathy, respectively. qRT-PCR and western blot were performed to measure expression levels of miR-125b, STAT3, HMGB1, and autophagy-related proteins. MTT assay was employed to examine LPS toxicity. Dual luciferase activity assay and CHIP were performed to validate interactions of miR-125b/STAT3 and STAT3/HMGB1 promoter. Immunostaining was used to assess the level of autophagic flux. ROS level was measured by fluorescence assay. Heart functions were examined via intracoronary Doppler ultrasound. miR-125b was diminished while STAT3 and HMGB1 were elevated in the heart tissue following CLP surgery and in LPS-treated H9C2 cells. LPS treatment up-regulated ROS generation and suppressed autophagic flux. Overexpression of miR-125b mimics or knockdown of STAT3 or HMGB1 alleviated LPS-induced hindrance of autophagic flux and ROS production. miR-125b directly targeted STAT3 mRNA and STAT3 bound with HMGB1 promoter. Overexpression of miR-125b mitigated myocardial dysfunction induced by CLP in vivo. Hyperactivation of STAT3/HMGB1 caused by reduced miR-125b contributes to ROS generation and the hindrance of autophagic flux during septic cardiomyopathy, leading to myocardial dysfunction.

Combined effects of hyperthermia and chemotherapy on the regulate autophagy of oral squamous cell carcinoma cells under a hypoxic microenvironment

Autophagy has a complex dual role in tumor survival or cell death owning to that is an evolutionarily conserved catabolic mechanism and provides the cells with a sustainable source of biomolecules and energy for the maintenance of homeostasis under stressful conditions such as tumor microenvironment. Hyperthermia is a rapidly growing field in cancer therapy and many advances have been made in understanding and applying the mechanisms of hyperthermia. The shallow oral and maxillofacial position and its abundant blood supply are favorable for the use of hyperthermia. However, the relationship between hyperthermia and autophagy has not been examined of oral squamous cell carcinoma (OSCC) in the tumor hypoxia microenvironment. Here, the expression level of autophagy relative genes is examined to explore autophagy effect on the responses of hyperthermia, hypoxia, and innutrition tumor microenvironment. It is founded that hyperthermia and hypoxia cause autophagy in starvation conditions; further, in hypoxia and innutrition tumor microenvironment, hyperthermia combines YC-1 and 3-MA could inhibit HIF-1α/BNIP3/Beclin1 signal pathway and decrease the secretion of HMGB1; moreover, the cell apoptosis rate increases with an inhibited of cell migration capacity. Thus, the present study demonstrated that combined use of YC-1 and 3-MA might increase the death of tumor cells in physiological and hyperthermic conditions, which could be relevant with the inhibition of autophagy in OSCC tumor cells under hypoxia microenvironment in vitro, which offers new insight into the therapy of OSCC and its application in treating others study carcinomas.

Atypical antipsychotics and oxidative cardiotoxicity: review of literature and future perspectives to prevent sudden cardiac death

Oxidative stress is considered the principal mediator of myocardial injury under pathological conditions. It is well known that reactive oxygen (ROS) or nitrogen species (RNS) are involved in myocardial injury and repair at the same time and that cellular damage is generally due to an unbalance between generation and elimination of the free radicals due to an inadequate mechanism of antioxidant defense or to an increase in ROS and RNS. Major adverse cardiovascular events are often associated with drugs with associated findings such as fibrosis or inflammation of the myocardium. Despite efforts in the preclinical phase of the development of drugs, cardiotoxicity still remains a great concern. Cardiac toxicity due to second-generation antipsychotics (clozapine, olanzapine, quetiapine) has been observed in preclinical studies and described in patients affected with mental disorders. A role of oxidative stress has been hypothesized but more evidence is needed to confirm a causal relationship. A better knowledge of cardiotoxicity mechanisms should address in the future to establish the right dose and length of treatment without impacting the physical health of the patients.

The Potential Role of Polyphenols in Oxidative Stress and Inflammation Induced by Gut Microbiota in Alzheimer's Disease

Gut microbiota (GM) play a role in the metabolic health, gut eubiosis, nutrition, and physiology of humans. They are also involved in the regulation of inflammation, oxidative stress, immune responses, central and peripheral neurotransmission. Aging and unhealthy dietary patterns, along with oxidative and inflammatory responses due to gut dysbiosis, can lead to the pathogenesis of neurodegenerative diseases, especially Alzheimer's disease (AD). Although the exact mechanism between AD and GM dysbiosis is still unknown, recent studies claim that secretions from the gut can enhance hallmarks of AD by disturbing the intestinal permeability and blood-brain barrier via the microbiota-gut-brain axis. Dietary polyphenols are the secondary metabolites of plants that possess anti-oxidative and anti-inflammatory properties and can ameliorate gut dysbiosis by enhancing the abundance of beneficial bacteria. Thus, modulation of gut by polyphenols can prevent and treat AD and other neurodegenerative diseases. This review summarizes the role of oxidative stress, inflammation, and GM in AD. Further, it provides an overview on the ability of polyphenols to modulate gut dysbiosis, oxidative stress, and inflammation against AD.