Targeting BMAL1 reverses drug resistance of acute myeloid leukemia cells and promotes ferroptosis through HMGB1-GPX4 signaling pathway.

PURPOSE: Acute myeloid leukemia (AML) is a refractory hematologic malignancy that poses a serious threat to human health. Exploring alternative therapeutic strategies capable of inducing alternative modes of cell death, such as ferroptosis, holds great promise as a viable and effective intervention. METHODS: We analyzed online database data and collected clinical samples to verify the expression and function of BMAL1 in AML. We conducted experiments on AML cell proliferation, cell cycle, ferroptosis, and chemotherapy resistance by overexpressing/knocking down BMAL1 and using assays such as MDA detection and BODIPY 581/591 C11 staining. We validated the transcriptional regulation of HMGB1 by BMAL1 through ChIP assay, luciferase assay, RNA level detection, and western blotting. Finally, we confirmed the results of our cell experiments at the animal level. RESULTS: BMAL1 up-regulation is an observed phenomenon in AML patients. Furthermore, there existed a strong correlation between elevated levels of BMAL1 expression and inferior prognosis in individuals with AML. We found that knocking down BMAL1 inhibited AML cell growth by blocking the cell cycle. Conversely, overexpressing BMAL1 promoted AML cell proliferation. Moreover, our research results revealed that BMAL1 inhibited ferroptosis in AML cells through BMAL1-HMGB1-GPX4 pathway. Finally, knocking down BMAL1 can enhance the efficacy of certain first-line cancer therapeutic drugs, including venetoclax, dasatinib, and sorafenib. CONCLUSION: Our research results suggest that BMAL1 plays a crucial regulatory role in AML cell proliferation, drug resistance, and ferroptosis. BMAL1 could be a potential important therapeutic target for AML.

Tumor cells express and maintain HMGB1 in the reduced isoform to enhance CXCR4-mediated migration.

During inflammation and tissue regeneration, the alarmin High Mobility Group Box 1 (HMGB1), in its reduced isoform, enhances the activity of the chemokine CXCL12, forming a heterocomplex that acts via the chemokine receptor CXCR4. Despite the established roles of both HMGB1 and CXCL12 in tumor progression and metastatic spread to distal sites, the role of the CXCL12/HMGB1 heterocomplex in cancer has never been investigated. By employing a newly established mass spectrometry protocol that allows an unambiguous distinction between reduced (red-HMGB1) and oxidized (ox-HMGB1) HMGB1 isoforms in cell lysates, we demonstrate that human epithelial cells derived from breast (MCF-7 and MDA-MB-231) and prostate (PC-3) cancer predominantly express red-HMGB1, while primary CD3+ T lymphocytes from peripheral blood express both HMGB1 isoforms. All these cancer cells release HMGB1 in the extracellular microenvironment together with varying concentrations of thioredoxin and thioredoxin reductase. The CXCL12/HMGB1 heterocomplex enhances, via CXCR4, the directional migration and invasiveness of cancer cells characterized by high metastatic potential that possess a fully active thioredoxin system, contributing to maintain red-HMGB1. On the contrary, cancer cells with low metastatic potential, lack thioredoxin reductase, promptly uptake CXCL12 and fail to respond to the heterocomplex. Our study demonstrates that the responsiveness of cancer cells to the CXCL12/HMGB1 heterocomplex, resulting in enhanced cell migration and invasiveness, depends on the maintenance of HMGB1 in its reduced isoform, and suggests disruption of the heterocomplex as a potential therapeutic target to inhibit invasion and metastatic spread in cancer therapies.

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-1ß), 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.

MSC-derived exosomal miR-140-3p improves cognitive dysfunction in sepsis-associated encephalopathy by HMGB1 and S-lactoylglutathione metabolism.

MiRNAs in mesenchymal stem cells (MSCs)-derived exosome (MSCs-exo) play an important role in the treatment of sepsis. We explored the mechanism through which MSCs-exo influences cognitive impairment in sepsis-associated encephalopathy (SAE). Here, we show that miR-140-3p targeted Hmgb1. MSCs-exo plus miR-140-3p mimic (Exo) and antibiotic imipenem/cilastatin (ABX) improve survival, weight, and cognitive impairment in cecal ligation and puncture (CLP) mice. Exo and ABX inhibit high mobility group box 1 (HMGB1), IBA-1, interleukin (IL)-1ß, IL-6, iNOS, TNF-α, p65/p-p65, NLRP3, Caspase 1, and GSDMD-N levels. In addition, Exo upregulates S-lactoylglutathione levels in the hippocampus of CLP mice. Our data further demonstrates that Exo and S-lactoylglutathione increase GSH levels in LPS-induced HMC3 cells and decrease LD and GLO2 levels, inhibiting inflammatory responses and pyroptosis. These findings suggest that MSCs-exo-mediated delivery of miR-140-3p ameliorates cognitive impairment in mice with SAE by HMGB1 and S-lactoylglutathione metabolism, providing potential therapeutic targets for the clinical treatment of SAE.

Click Chemistry-Based Force Spectroscopy Revealed Enhanced Binding Dynamics of Phosphorylated HMGB1 to Cisplatin-DNA.

Cisplatin, a cornerstone in cancer chemotherapy, is known for its DNA-binding capacity and forms lesions that lead to cancer cell death. However, the repair of these lesions compromises cisplatin's effectiveness. This study investigates how phosphorylation of HMGB1, a nuclear protein, modifies its binding to cisplatin-modified DNA (CP-DNA) and thus protects it from repair. Despite numerous methods for detecting protein-DNA interactions, quantitative approaches for understanding their molecular mechanism remain limited. Here, we applied click chemistry-based single-molecule force spectroscopy, achieving high-precision quantification of the interaction between phosphorylated HMGB1 and CP-DNA. This method utilizes a synergy of click chemistry and enzymatic ligation for precise DNA-protein immobilization and interaction in the system. Our results revealed that HMGB1 binds to CP-DNA with a significantly high rupture force of ∼130 pN, stronger than most natural DNA-protein interactions and varying across different DNA sequences. Moreover, Ser14 is identified as the key phosphorylation site, enhancing the interaction's kinetic stability by 35-fold. This increase in stability is attributed to additional hydrogen bonding suggested by molecular dynamics (MD) simulations. Our findings not only reveal the important role of phosphorylated HMGB1 in potentially improving cisplatin's therapeutic efficacy but also provide a precise method for quantifying protein-DNA interactions.

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.

Gallic acid attenuates torsion/detorsion-induced testicular injury in rats through suppressing of HMGB1/NF-κB axis and endoplasmic reticulum stress.

It was aimed to evaluate whether gallic acid (GA) have a beneficial effect in the testicular ischemia/reperfusion injury (IRI) model in rats for the first time. Testicular malondialdehyde, 8-hydroxy-2'-deoxyguanosine, superoxide dismutase, catalase, high mobility group box 1 protein, nuclear factor kappa B, tumor necrosis factoralpha, interleukin-6, myeloperoxidase, 78-kDa glucose-regulated protein, activating transcription factor 6, CCAAT-enhancer-binding protein homologous protein and caspase-3 levels were determined using colorimetric methods. The oxidative stress, inflammation, endoplasmic reticulum stress and apoptosis levels increased statistically significantly in the IRI group compared with the sham operated group (p < 0.05). GA application improved these damage significantly (p < 0.05). Moreover, it was found that the results of histological examinations supported the biochemical results to a statistically significant extent. Our findings suggested that GA may be evaluated as a protective agent against testicular IRI.

Zinc alleviates high fat diet-induced spermatogenic dysfunction in Wistar rats: role of oxidative stress, HMGB1 and inflammasome.

Whether chronic inflammation in the genital tract induced by obesity shares in spermatogenic dysfunction is not clearly known. We aimed to study the effect of high fat diet (HFD) on spermatogenesis, seminal oxidative stress (malondialdehyde (MDA)) and inflammatory markers (high mobility group box 1 (HMGB1), nucleotide-binding oligomerization domain, leucine rich repeat and pyrin-3 domain containing (NLRP3)) in the rat testes and the role of zinc on testicular dysfunction and chronic inflammation in high fat diet (HFD) fed rat testes. This parallel group comparative experimental study included 36 male wistar rats divided into 3 groups: group A (fed on normal control diet); group B (fed on high fat diet (HFD) only); and group C (fed on HFD with zinc supplementation 3.2 mg/kg/day orally). At the end of the 12th week, sperm count, viability and motility were assessed by computer-assisted seemen analysis (CASA), seminal malondialdehyde measured by calorimetry and histopathological examination of testicular sections was done. Immunohistochemical staining was done for HMGB1 and NLRP3 evaluation. Sperm count was lowest in group B. Groups A and C showed statistically significant higher mean sperm vitality, total and progressive motility scores (p < 0.001), while no difference was found between the groups A and C (p > 0.05). Seminal malondialdehyde level was significantly highest in group B. Tubular diameter, epithelial height and Johnsen score were significantly lowest in group B. Significantly higher HMGB1 and NLRP3 levels were demonstrated in group B (p < 0.001). Obesity is associated with testicular dysfunction, testicular oxidative stress and increased testicular HMGB1 and NLRP3. We suggest a beneficial effect of zinc on testicular function in HFD-rats.

Impact of HMGB1 on cancer development and therapeutic insights focused on CNS malignancy.

The present study explores the complex roles of High Mobility Group Box 1 (HMGB1) in the context of cancer development, emphasizing glioblastoma (GBM) and other central nervous system (CNS) cancers. HMGB1, primarily known for its involvement in inflammation and angiogenesis, emerges as a multifaceted player in the tumorigenesis of GBM. The overexpression of HMGB1 correlates with glioma malignancy, influencing key pathways like RAGE/MEK/ERK and RAGE/Rac1. Additionally, HMGB1 secretion is linked to the maintenance of glioma stem cells (GSCs) and contributes to the tumor microenvironment's (TME) vascular leakiness. Henceforth, our review discusses the bidirectional impact of HMGB1, acting as both a promoter of tumor progression and a mediator of anti-tumor immune responses. Notably, HMGB1 exhibits tumor-suppressive roles by inducing apoptosis, limiting cellular proliferation, and enhancing the sensitivity of GBM to therapeutic interventions. This dualistic nature of HMGB1 calls for a nuanced understanding of its implications in GBM pathogenesis, offering potential avenues for more effective and personalized treatment strategies. The findings underscore the need to explore HMGB1 as a prognostic marker, therapeutic target, and a promising tool for stimulating anti-tumor immunity in GBM.

RG-I pectin-like polysaccharide from Rosa chinensis inhibits inflammation and fibrosis associated to HMGB1/TLR4/NF-κB signaling pathway to improve non-alcoholic steatohepatitis.

A novel RG-I pectin-like polysaccharide, YJ3A1, was purified from the flowers of Rosa chinensis and its structure and hepatoprotective effect in vivo and in vitro were investigated. The backbone of this polysaccharide is mainly composed of 1, 4-galactan, 1, 4-linked α-GalpA and 1, 2-linked α-Rhap disaccharide repeating unit attached by 1, 6-linked ß-Galp or 1, 5-linked α-Araf on C-4 of the Rhap. Interestingly, oral administration of YJ3A1 significantly ameliorates NASH-associated inflammation, oxidative stress and fibrosis and does not affect the liver morphology of normal mice at a dose of 50 mg/kg. The mechanism study suggests that the biological activity may associate to inactivating of high-mobility group box 1 protein (HMGB1)/TLR4/NF-κB and Akt signaling pathways by restraining the expression and release of HMGB1, thereby impeding the effect of NASH. The current findings outline a novel leading polysaccharide for new drug candidate development against NASH.

Stretch Causes cffDNA and HMGB1-Mediated Inflammation and Cellular Stress in Human Fetal Membranes.

Danger-associated molecular patterns (DAMPs) are elevated within the amniotic cavity, and their increases correlate with advancing gestational age, chorioamnionitis, and labor. Although the specific triggers for their release in utero remain unclear, it is thought that they may contribute to the initiation of parturition by influencing cellular stress mechanisms that make the fetal membranes (FMs) more susceptible to rupture. DAMPs induce inflammation in many different tissue types. Indeed, they precipitate the subsequent release of several proinflammatory cytokines that are known to be key for the weakening of FMs. Previously, we have shown that in vitro stretch of human amnion epithelial cells (hAECs) induces a cellular stress response that increases high-mobility group box-1 (HMGB1) secretion. We have also shown that cell-free fetal DNA (cffDNA) induces a cytokine response in FM explants that is fetal sex-specific. Therefore, the aim of this work was to further investigate the link between stretch and the DAMPs HMGB1 and cffDNA in the FM. These data show that stretch increases the level of cffDNA released from hAECs. It also confirms the importance of the sex of the fetus by demonstrating that female cffDNA induced more cellular stress than male fetuses. Our data treating hAECs and human amnion mesenchymal cells with HMGB1 show that it has a differential effect on the ability of the cells of the amnion to upregulate the proinflammatory cytokines and propagate a proinflammatory signal through the FM that may weaken it. Finally, our data show that sulforaphane (SFN), a potent activator of Nrf2, is able to mitigate the proinflammatory effects of stretch by decreasing the levels of HMGB1 release and ROS generation after stretch and modulating the increase of key cytokines after cell stress. HMGB1 and cffDNA are two of the few DAMPs that are known to induce cytokine release and matrix metalloproteinase (MMP) activation in the FMs; thus, these data support the general thesis that they can function as potential central players in the normal mechanisms of FM weakening during the normal distension of this tissue at the end of a normal pregnancy.

Effects of butyrate on intestinal ischemia-reperfusion injury via the HMGB1-TLR4-MyD88 signaling pathway.

BACKGROUND: This study combined bioinformatics and experimental verification in a mouse model of intestinal ischemia-reperfusion injury (IRI) to explore the protection mechanism exerted by butyrate against IRI. METHODS: GeneCards, Bioinformatics Analysis Tool for Molecular Mechanisms of Traditional Chinese Medicine and GSE190581 were used to explore the relationship between butyrate and IRI and aging. Protein-protein interaction networks involving butyrate and IRI were constructed via the STRING database, with hub gene analysis performed through Cytoscape. Functional enrichment analysis was conducted on intersection genes. A mouse model of IRI was established, followed by direct arterial injection of butyrate. The experiment comprised five groups: normal, sham, model, vehicle, low-dose butyrate, and high-dose butyrate. Intestinal tissue observation was done via transmission electron microscopy (TEM), histological examination via hematoxylin and eosin (H&E) staining, tight junction proteins detection via immunohistochemistry, and Western blot analysis of hub genes. Drug-target interactions were evaluated through molecular docking. RESULTS: Butyrate protected against IRI by targeting 458 genes, including HMGB1 and TLR4. Toll-like receptor pathway was implicated. Butyrate improved intestinal IRI by reducing mucosal damage, increasing tight junction proteins, and lowering levels of HMGB1, TLR4, and MyD88. Molecular docking showed strong binding energies between butyrate and HMGB1 (-3.7 kcal/mol) and TLR4 (-3.8 kcal/mol). CONCLUSIONS: According to bioinformatics predictions, butyrate mitigates IRI via multiple-target and multiple-channel mechanisms. The extent of IRI can be reduced by butyrate through the inhibition of the HMGB1-TLR4-MyD88 signaling pathway, which is related to senescence.

Du-moxibustion ameliorates depression-like behavior and neuroinflammation in chronic unpredictable mild stress-induced mice.

BACKGROUND: Neuroinflammation is involved in the advancement of depression. Du-moxibustion can treat depression. Here, we explored whether Du-moxibustion could alleviate neuroglia-associated neuro-inflammatory process in chronic unpredictable mild stress (CUMS) mice. METHODS: C57BL/6J mice were distributed into five groups. Except for the CON group, other four groups underwent CUMS for four consecutive weeks, and Du-moxibustion was given simultaneously after modeling. Behavioral tests were then carried out. Additionally, Western blot was conducted to measure the relative expression levels of high-mobility group box 1 (HMGB1), toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and nuclear factor-kappa B (NF-κB). Immunofluorescence was employed to evaluate the positive cells of ionized calcium binding adapter molecule 1 (Iba-1) and glial fibrillary acidic protein (GFAP). Furthermore, interleukin-1 beta (IL-1ß) and tumor necrosis factor-alpha (TNF-α) were analyzed using an ELISA assay. RESULTS: We found that CUMS induced depression-like behaviors, such as reduced sucrose preference ratio, decreased locomotor and exploratory activity, decreased the time in open arms and prolonged immobility. Furthermore, versus the CON group, the expression of HMGB1, TLR4, MyD88, NF-κB, positive cells of Iba-1, IL-1ß and TNF-α were increased but positive cells of GFAP were decreased in CUMS group. However, the detrimental effects were ameliorated by treatment with CUMS+FLU and CUMS+DM. LIMITATIONS: A shortage of this study is that only CUMS model of depression were used, while other depression model were not included. CONCLUSIONS: Du-moxibustion alleviates depression-like behaviors in CUMS mice mainly by reducing neuroinflammation, which offers novel insights into the potential treatment of depression.

Quinic acid regulated TMA/TMAO-related lipid metabolism and vascular endothelial function through gut microbiota to inhibit atherosclerotic.

BACKGROUND: Quinic acid (QA) and its derivatives have good lipid-lowering and hepatoprotective functions, but their role in atherosclerosis remains unknown. This study attempted to investigate the mechanism of QA on atherogenesis in Apoe-/- mice induced by HFD. METHODS: HE staining and oil red O staining were used to observe the pathology. The PCSK9, Mac-3 and SM22a expressions were detected by IHC. Cholesterol, HMGB1, TIMP-1 and CXCL13 levels were measured by biochemical and ELISA. Lipid metabolism and the HMGB1-SREBP2-SR-BI pathway were detected by PCR and WB. 16 S and metabolomics were used to detect gut microbiota and serum metabolites. RESULTS: QA or low-frequency ABX inhibited weight gain and aortic tissue atherogenesis in HFD-induced Apoe-/- mice. QA inhibited the increase of cholesterol, TMA, TMAO, CXCL13, TIMP-1 and HMGB1 levels in peripheral blood of Apoe-/- mice induced by HFD. Meanwhile, QA or low-frequency ABX treatment inhibited the expression of CAV-1, ABCA1, Mac-3 and SM22α, and promoted the expression of SREBP-1 and LXR in the vascular tissues of HFD-induced Apoe-/- mice. QA reduced Streptococcus_danieliae abundance, and promoted Lactobacillus_intestinalis and Ileibacterium_valens abundance in HFD-induced Apoe-/- mice. QA altered serum galactose metabolism, promoted SREBP-2 and LDLR, inhibited IDOL, FMO3 and PCSK9 expression in liver of HFD-induced Apoe-/- mice. The combined treatment of QA and low-frequency ABX regulated microbe-related Glycoursodeoxycholic acid and GLYCOCHENODEOXYCHOLATE metabolism in HFD-induced Apoe-/- mice. QA inhibited TMAO or LDL-induced HCAECs damage and HMGB1/SREBP2 axis dysfunction, which was reversed by HMGB1 overexpression. CONCLUSIONS: QA regulated the gut-liver lipid metabolism and chronic vascular inflammation of TMA/TMAO through gut microbiota to inhibit the atherogenesis in Apoe-/- mice, and the mechanism may be related to the HMGB1/SREBP2 pathway.

High mobility group box 1 mediates inflammatory responses in malignant peritoneal mesothelioma.

BACKGROUND: Serum high mobility group box 1 (HMGB1) serves as a diagnostic biomarker for malignant peritoneal mesothelioma (MPM) patients, yet its diagnostic significance within MPM tumor tissues remains uncertain. This study aims to elucidate the roles of HMGB1 in MPM. METHODS: HMGB1 expression analysis was conducted in both tumor and adjacent non-cancerous tissues collected from MPM patients. The two-year follow-up of MPM patients commenced from the diagnosis date. Inflammatory cytokine analysis was performed on these tissues, and Pearson correlation coefficient analysis was applied to examine variable relationships. In vitro assays included constructing an HMGB1 knockdown cell line, assessing cell viability, apoptosis, and inflammatory cytokine levels to delineate HMGB1's roles in MPM. RESULTS: HMGB1 overexpression was observed in MPM tumor tissues, particularly in stages III-IV. Diagnostic implications of HMGB1 for MPM were evident, augmenting its diagnostic value. HMGB1 overexpression correlated with diminished survival rates. Positive correlations existed between inflammatory cytokines and HMGB1 in MPM tumor tissues and cell lines. Suppression of HMGB1 regulated cell growth and apoptosis in MPM cell lines. CONCLUSION: HMGB1 exhibits diagnostic potential for MPM and modulates inflammatory responses within the disease context.

Neutrophil Elastase Degrades Histone Deacetylases and Sirtuin 1 in Primary Human Monocyte Derived Macrophages.

Neutrophil elastase (NE) is taken up by macrophages, retains intracellular protease activity, and induces a pro-inflammatory phenotype. However, the mechanism of NE-induced pro-inflammatory polarization of macrophages is not well understood. We hypothesized that intracellular NE degrades histone deacetylases (HDAC) and Sirtuins, disrupting the balance of lysine acetylation and deacetylation and resulting in nuclear to cytoplasmic translocation of a major alarmin, High Mobility Group Box 1 (HMGB1), a pro-inflammatory response in macrophages. Human blood monocytes were obtained from healthy donors or from subjects with cystic fibrosis (CF) or chronic obstructive pulmonary disease (COPD). Monocytes were differentiated into blood monocyte derived macrophages (BMDMs) in vitro. Human BMDMs were exposed to NE or control vehicle, and the abundance of HDACs and Sirtuins was determined by Western blotting of total cell lysates or nuclear extracts or determined by ELISA. HDAC, Sirtuin, and Histone acetyltransferase (HAT) activities were measured. NE degraded most HDACs and Sirtuin (Sirt)1, resulting in decreased HDAC and sirtuin activities, with minimal change in HAT activity. We then evaluated whether the NE-induced loss of Sirt activity or loss of HDAC activities would alter the cellular localization of HMGB1. NE treatment or treatment with Trichostatin A (TSA), a global HDAC inhibitor, both increased HMGB1 translocation from the nucleus to the cytoplasm, consistent with HMGB1 activation. NE significantly degraded Class I and II HDAC family members and Sirt 1, which shifted BMDMs to a pro-inflammatory phenotype.

Peripheral HMGB1 is linked to O3 pathology of disease-associated astrocytes and amyloid.

INTRODUCTION: Ozone (O3) is an air pollutant associated with Alzheimer's disease (AD) risk. The lung-brain axis is implicated in O3-associated glial and amyloid pathobiology; however, the role of disease-associated astrocytes (DAAs) in this process remains unknown. METHODS: The O3-induced astrocyte phenotype was characterized in 5xFAD mice by spatial transcriptomics and proteomics. Hmgb1fl/fl LysM-Cre+ mice were used to assess the role of peripheral myeloid cell high mobility group box 1 (HMGB1). RESULTS: O3 increased astrocyte and plaque numbers, impeded the astrocyte proteomic response to plaque deposition, augmented the DAA transcriptional fingerprint, increased astrocyte-microglia contact, and reduced bronchoalveolar lavage immune cell HMGB1 expression in 5xFAD mice. O3-exposed Hmgb1fl/fl LysM-Cre+ mice exhibited dysregulated DAA mRNA markers. DISCUSSION: Astrocytes and peripheral myeloid cells are critical lung-brain axis interactors. HMGB1 loss in peripheral myeloid cells regulates the O3-induced DAA phenotype. These findings demonstrate a mechanism and potential intervention target for air pollution-induced AD pathobiology. HIGHLIGHTS: Astrocytes are part of the lung-brain axis, regulating how air pollution affects plaque pathology. Ozone (O3) astrocyte effects are associated with increased plaques and modified by plaque localization. O3 uniquely disrupts the astrocyte transcriptomic and proteomic disease-associated astrocyte (DAA) phenotype in plaque associated astrocytes (PAA). O3 changes the PAA cell contact with microglia and cell-cell communication gene expression. Peripheral myeloid cell high mobility group box 1 regulates O3-induced transcriptomic changes in the DAA phenotype.

The Ability of Clinically Relevant Chemotherapeutics to Induce Immunogenic Cell Death in Squamous Cell Carcinoma.

BACKGROUND: Immunogenic cell death (ICD) is a crucial mechanism for triggering the adaptive immune response in cancer patients. Damage-associated molecular patterns (DAMPs) are critical factors in the detection of ICD. Chemotherapeutic drugs can cause ICD and the release of DAMPs. The aim of this study was to assess the potential for paclitaxel and platinum-based chemotherapy regimens to induce ICD in squamous cell carcinoma (SCC) cell lines. In addition, we examined the immunostimulatory effects of clinically relevant chemotherapeutic regimens utilized in the treatment of SCC. METHODS: We screened for differentially expressed ICD markers in the supernatants of three SCC cell lines following treatment with various chemotherapeutic agents. The ICD markers included Adenosine Triphosphate (ATP), Calreticulin (CRT), Annexin A1 (ANXA 1), High Mobility Group Protein B1 (HMGB1), and Heat Shock Protein 70 (HSP70). A vaccination assay was also employed in C57BL/6J mice to validate our in vitro findings. Lastly, the levels of CRT and HMGB1 were evaluated in Serum samples from SCC patients. RESULTS: Addition of the chemotherapy drugs cisplatin (DDP), carboplatin (CBP), nedaplatin (NDP), oxaliplatin (OXA) and docetaxel (DOC) increased the release of ICD markers in two of the SCC cell lines. Furthermore, mice that received vaccinations with cervical cancer cells treated with DDP, CBP, NDP, OXA, or DOC remained tumor-free. Although CBP induced the release of ICD-associated molecules in vitro, it did not prevent tumor growth at the vaccination site in 40% of mice. In addition, both in vitro and in vivo results showed that paclitaxel (TAX) and LBP did not induce ICD in SCC cells. CONCLUSION: The present findings suggest that chemotherapeutic agents can induce an adjuvant effect leading to the extracellular release of DAMPs. Of the agents tested here, DDP, CBP, NDP, OXA and DOC had the ability to act as inducers of ICD.

CAMSAP3-mediated regulation of HMGB1 acetylation and subcellular localization in lung cancer cells: Implications for cell death modulation.

BACKGROUND: Deregulation of cell death is a common characteristic of cancer, and resistance to this process often occurs in lung cancer. Understanding the molecular mechanisms underlying an aberrant cell death is important. Recent studies have emphasized the involvement of calmodulin-regulated spectrin-associated protein 3 (CAMSAP3) in lung cancer aggressiveness, its influence on cell death regulation remains largely unexplored. METHODS: CAMSAP3 was knockout in lung cancer cells using CRISPR-Cas9 system. Cell death and autophagy were evaluated using MTT and autophagic detection assays. Protein interactions were performed by proteomic analysis and immunoprecipitation. Protein expressions and their cytoplasmic localization were analyzed through immunoblotting and immunofluorescence techniques. RESULTS: This study reveals a significant correlation between low CAMSAP3 expression and poor overall survival rates in lung cancer patients. Proteomic analysis identified high mobility group box 1 (HMGB1) as a candidate interacting protein involved in the regulation of cell death. Treatment with trichostatin A (TSA), an inhibitor of histone deacetylases (HDACs) resulted in increased HMGB1 acetylation and its translocation to the cytoplasm and secretion, thereby inducing autophagic cell death. However, this process was diminished in CAMSAP3 knockout lung cancer cells. Mechanistically, immunoprecipitation indicated an interaction between CAMSAP3 and HMGB1, particularly with its acetylated form, in which this complex was elevated in the presence of TSA. CONCLUSIONS: CAMSAP3 is prerequisite for TSA-mediated autophagic cell death by interacting with cytoplasmic acetylated HMGB1 and enhancing its release. SIGNIFICANT: This finding provides molecular insights into the role of CAMSAP3 in regulating cell death, highlighting its potential as a therapeutic target for lung cancer treatment.

A patent review on HMGB1 inhibitors for the treatment of liver diseases.

INTRODUCTION: HMGB1 is a non-histone chromatin protein released or secreted in response to tissue damage or infection. Extracellular HMGB1, as a crucial immunomodulatory factor, binds with several different receptors to innate inflammatory responses that aggravate acute and chronic liver diseases. The increased levels of HMGB1 have been reported in various liver diseases, highlighting that it represents a potential biomarker and druggable target for therapeutic development. AREAS COVERED: This review summarizes the current knowledge on the structure, function, and interacting receptors of HMGB1 and its significance in multiple liver diseases. The latest patented and preclinical studies of HMGB1 inhibitors (antibodies, peptides, and small molecules) for liver diseases are summarized by using the keywords 'HMGB1,' 'HMGB1 antagonist, HMGB1-inhibitor,' 'liver disease' in Web of Science, Google Scholar, Google Patents, and PubMed databases in the year from 2017 to 2023. EXPERT OPINIONS: In recent years, extensive research on HMGB1-dependent inflammatory signaling has discovered potent inhibitors of HMGB1 to reduce the severity of liver injury. Despite significant progress in the development of HMGB1 antagonists, few of them are approved for clinical treatment of liver-related diseases. Developing safe and effective specific inhibitors for different HMGB1 isoforms and their interaction with receptors is the focus of future research.