Aloperine Ameliorates Acetaminophen-Induced Acute Liver Injury through HMGB1/TLR4/NF-κB and NLRP3/Inflammasome Pathway.

Purpose: Aloperine (ALO), an alkaloid isolated from Sophora alopecuroides L., possesses multiple pharmacological activities and holds a promise potential for the treatment of various clinical conditions, including skin hypersensitivity, cancer, and inflammatory disorders. The purpose of this study was to investigate the role of ALO in acetaminophen (N-acetyl-para-aminophenol (APAP))-induced acute liver injury and its underlying mechanisms. Materials and Methods: An animal model of acute liver injury was induced by intraperitoneal injection of APAP (150 mg/kg). Prior to APAP injection, ALO (40 mg/kg) was administered daily for 7 consecutive days. Serum alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase levels were then measured using an automated chemical analyzer. Histopathological changes were evaluated using hematoxylin and eosin staining. Oxidative stress levels were measured by detecting superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA). Pro-inflammatory cytokines were detected in serum and liver tissues using ELISA and quantitative real-time polymerase chain reaction (q-PCR). The expression of members of the HMGB1/TLR4/NF-κB signaling pathway and NLRP3 inflammasome were determined by Western blot and/or q-PCR. In addition, the expression and location of NLRP3, cleaved caspase-1, high-mobility group box 1 (HMGB1), and phosphorylated p65 (p-p65) were detected by immunofluorescence. Results: Pretreatment with ALO significantly protected mice from APAP-induced acute liver injury, with decreased MDA content, and significantly increased GSH and SOD activities. Furthermore, ALO pretreatment reduced the release of pro-inflammatory cytokines (IL-1ß and TNF-α) and decreased the expression of caspase-1, cleaved caspase-1, and NLRP3. In addition, ALO pretreatment also inhibited the activation of the HMGB1/TLR4/NF-κB signaling pathway. Conclusion: Taken together, ALO can ameliorate APAP-induced acute liver injury by inhibiting oxidative stress, inflammation by inhibiting the HMGB1/TLR4/NF-κB, and NLRP3/inflammasome pathway.

HMGB2-induced calreticulin translocation required for immunogenic cell death and ferroptosis of cancer cells are controlled by the nuclear exporter XPO1.

Cisplatin and oxaliplatin cause the secretion of high mobility group box 1 (HMGB1) protein from cancer cells, which is necessary for initiation of immunogenic cell death (ICD). Calreticulin (CRT) translocation from the endoplasmic reticulum to the plasma membrane is also required; oxaliplatin induces this translocation but cisplatin does not. We have discovered that oxaliplatin causes the secretion of both HMGB1 and HMGB2 from the cell nucleus into the extracellular milieu. We previously showed that cisplatin-mediated secretion of HMGB1 is controlled by the nuclear exporter XPO1 (chromosomal maintenance 1; CRM1). We now find that XPO1 regulates oxaliplatin-mediated secretion of both HMGB1 and HMGB2. XPO1 inhibition causes nuclear accumulation of both proteins, inhibition of oxaliplatin-mediated ferroptosis of colon cancer cells, and inhibition of CRT translocation to the plasma membrane of lung and colon cancer cells. Incubation of cancer cells with cell targeted (CT)-HMGB2 confirmed that HMGB2 is required for the CRT translocation. Furthermore, CT-HMGB2 is three orders of magnitude more potent at inducing CRT translocation than oxaliplatin.

Induction of immunogenic cell death and enhancement of the radiation-induced immunogenicity by chrysin in melanoma cancer cells.

Chrysin is a natural flavonoid with anti-cancer effects. Despite its beneficial effects, little information is available regarding its immunogenic cell death (ICD) properties. In this work, we hypothesized that chrysin can potentiate radiotherapy(RT)-induced immunogenicity in melanoma cell line (B16-F10). We examined the effects of chrysin alone and in combination with radiation on ICD induction in B16-F10 cells. Cell viability was assessed using an MTT assay. Cell apoptosis and calreticulin (CRT) exposure were determined using flow cytometry. Western blotting and ELISA assay were employed to examine changes in protein expression. Combination therapy exhibited a synergistic effect, with an optimum combination index of 0.66. The synergistic anti-cancer effect correlated with increased cell apoptosis in cancer cells. Compared to the untreated control, chrysin alone and in combination with RT induced higher levels of DAMPs, such as CRT, HSP70, HMGB1, and ATP. The protein expression of p-STAT3/STAT3 and PD-L1 was reduced in B16-F10 cells exposed to chrysin alone and in combination with RT. Conditioned media from B16-F10 cells exposed to mono-and combination treatments elicited IL-12 secretion in dendritic cells (DCs), inducing a Th1 response. Our findings revealed that chrysin could induce ICD and intensify the RT-induced immunogenicity.

Elevated levels of damage-associated molecular patterns HMGB1 and S100A8/A9 coupled with toll-like receptor-triggered monocyte activation are associated with inflammation in patients with myelofibrosis.

Inflammation plays a pivotal role in the pathogenesis of primary and post-essential thrombocythemia or post-polycythemia vera myelofibrosis (MF) in close cooperation with the underlying molecular drivers. This inflammatory state is induced by a dynamic spectrum of inflammatory cytokines, although recent evidence points to the participation of additional soluble inflammatory mediators. Damage-associated molecular patterns (DAMPs) represent endogenous signals released upon cell death or damage which trigger a potent innate immune response. We assessed the contribution of two prototypical DAMPs, HMGB1 and S100A8/A9, to MF inflammation. Circulating HMGB1 and S100A8/A9 were elevated in MF patients in parallel to the degree of systemic inflammation and levels increased progressively during advanced disease stages. Patients with elevated DAMPs had higher frequency of adverse clinical features, such as anemia, and inferior survival, suggesting their contribution to disease progression. Monocytes, which are key players in MF inflammation, were identified as a source of S100A8/A9 but not HMGB1 release, while both DAMPs correlated with cell death parameters, such as serum LDH and cell-free DNA, indicating that passive release is an additional mechanism leading to increased DAMPs. HMGB1 and S100A8/A9 promote inflammation through binding to Toll-like receptor (TLR) 4, whereas the former also binds TLR2. Monocytes from MF patients were shown to be hyperactivated at baseline, as reflected by higher CD11b and tissue factor exposure and increased expression levels of proinflammatory cytokines IL-1ß and IL-6. Patient monocytes showed preserved TLR4 and TLR2 expression and were able to mount normal or even exacerbated functional responses and cytokine upregulation following stimulation of TLR4 and TLR2. Elevated levels of endogenous TLR ligands HMGB1 and S100A8/A9 coupled to the finding of preserved or hyperreactive TLR-triggered responses indicate that DAMPs may promote monocyte activation and cytokine production in MF, fueling inflammation. Plasma IL-1ß and IL-6 were elevated in MF and correlated with DAMPs levels, raising the possibility that DAMPs could contribute to cytokine generation in vivo. In conclusion, this study highlights that, in cooperation with classic proinflammatory cytokines, DAMPs represent additional inflammatory mediators that may participate in the generation of MF inflammatory state, potentially providing novel biomarkers of disease progression and new therapeutic targets.

Neuroprotective effect of Naochuxue prescription on intracerebral hemorrhage: inhibition of autophagy downregulating high mobility group box-1.

OBJECTIVE: To determine the molecular mechanisms underlying the neuroprotective effects of Naochuxue prescription (,NCXP) in rats with intracerebral hemorrhage (ICH). METHODS: Sprague-Dawley rats were injected with collagenase to generate ICH models, which were then randomly divided into six groups, including control, sham, model, and three intervention groups. The intervention groups received different doses of NCXP (0.13, 0.26, and 0.52 g/kg) daily for 10 d. High-performance liquid chromatography (HPLC) was used to analyze the chemical characteristics of NCXP. The neurobehavioral outcomes of the rats were evaluated using neurological deficit scores (Zea Longa 5) and the corner turn test. Pathomorphological changes in perihematomal tissues after ICH were observed using hematoxylin and eosin staining. Immunohistochemistry (IHC) was used to detect the inflammation expression of interleukin 6 (IL-6) and toll-like receptor 4 (TLR4). High mobility group box-1 (HMGB1), Beclin1, microtubule-associated protein 1 light chain 3 beta (LC3), and sequestosome 1 (p62) were detected using real-time quantitative polymerase chain reaction and Western blotting in perihematomal tissues. RESULTS: HPLC showed that the NCXP had good stability. Rats with ICH had severe neurological function deficits compared to the control group. IHC results showed that NCXP significantly downregulated the expression of the inflammatory proteins IL-6 and TLR4. ICH rats treated with NCXP showed less neurological injury than the model group, accompanied by a significantly decreased expression of HMGB1, Beclin1, and LC3 and an increased expression of p62. CONCLUSIONS: The neuroprotective effect of NCXP alleviated inflammation and autophagy possibly by downregulating HMGB1 expression. However, further research on the signaling pathways is required to verify this hypothesis.

High Mobility Group Box-1 (HMGB1), a Key Mediator of Cognitive Decline in Neurotrauma with a Potential for Targeted Therapy: A Comprehensive Review.

Neurotrauma plays a significant role in secondary injuries by intensifying the neuroinflammatory response in the brain. High Mobility Group Box-1 (HMGB1) protein is a crucial neuroinflammatory mediator involved in this process. Numerous studies have hypothesized about the underlying pathophysiology of HMGB1 and its role in cognition, but a definitive link has yet to be established. Elevated levels of HMGB1 in the hippocampus and serum have been associated with declines in cognitive performance, particularly in spatial memory and learning. This review also found that inhibiting HMGB1 can improve cognitive deficits following neurotrauma. Interestingly, HMGB1 levels are linked to the modulation of neuroplasticity and may offer neuroprotective effects in the later stages of neurotraumatic events. Consequently, administering HMGB1 during the acute phase may help reduce neuroinflammatory effects that lead to cognitive deficits in the later stages of neurotrauma. However, further research is needed to understand the time-dependent regulation of HMGB1 and the clinical implications of treatments targeting HMGB1 after neurotrauma.

Unveiling senescence-associated ocular pathogenesis via lacrimal gland organoid magnetic bioassembly platform and HMGB1-Box A gene therapy.

Dry eye disease (DED) is a multifactorial aging disorder leading to tear film insufficiency and instability. Yet, an important knowledge gap lingers in understanding senescence-associated ocular pathogenesis, due to limited in vitro translational lacrimal gland (LG) models. Consequently, this remains a major roadblock to discover effective therapies for the restoration of tear film secretion. Herein, the authors reported the magnetic bioassembly of two LG organoid platforms to recapitulate functional and aging states. Using a proof-of-concept approach, porcine primary LG cells were assembled into organoids via a magnetic 3D bioprinting (M3DB) platform. This platform could form reproducible LG organoids with epithelial hallmarks (AQP5+) and exhibit epithelial secretory functions (lysozyme activity). DNA damage-induced senescence and cell death was induced with etoposide, and LG organoid hypofunction and senescence-associated pathogenesis were observed. To confer DNA protection against aging, a novel gene therapy with Box A domain of high-mobility group box-1 (HMGB1-Box A) previously established by our group, was applied here to prevent LG cellular senescence for the first time. HMGB1-Box A transfection prevented LG organoids from senescence-associated pathogenesis at the transcriptomic, metabolomic and proteomic levels. Thus, M3DB platforms could generate functional and DNA damage-induced senescence LG organoids, and this latter damage could be prevented with HMGB1-Box A gene therapy.

Cytosolic Hmgb1 accumulation in mesangial cells aggravates diabetic kidney disease progression via NFκB signaling pathway.

Diabetic kidney disease (DKD) is the predominant type of end-stage renal disease. Increasing evidence suggests thatglomerular mesangial cell (MC) inflammation is pivotal for cell proliferation and DKD progression. However, the exactmechanism of MC inflammation remains largely unknown. This study aims to elucidate the role of inflammatoryfactor high-mobility group box 1 (Hmgb1) in DKD. Inflammatory factors related to DKD progression are screened viaRNA sequencing (RNA-seq). In vivo and in vitro experiments, including db/db diabetic mice model, CCK-8 assay, EdUassay, flow cytometric analysis, Co-IP, FISH, qRT-PCR, western blot, single cell nuclear RNA sequencing (snRNA-seq),are performed to investigate the effects of Hmgb1 on the inflammatory behavior of MCs in DKD. Here, wedemonstrate that Hmgb1 is significantly upregulated in renal tissues of DKD mice and mesangial cells cultured withhigh glucose, and Hmgb1 cytopasmic accumulation promotes MC inflammation and proliferation. Mechanistically,Hmgb1 cytopasmic accumulation is two-way regulated by MC-specific cyto-lncRNA E130307A14Rik interaction andlactate-mediated acetylated and lactylated Hmgb1 nucleocytoplasmic translocation, and accelerates NFκB signalingpathway activation via directly binding to IκBα. Together, this work reveals the promoting role of Hmgb1 on MCinflammation and proliferation in DKD and helps expound the regulation of Hmgb1 cytopasmic accumulation in twoways. In particular, Hmgb1 may be a promising therapeutic target for DKD.

Roles of HMGB1 on life-threatening traumatic brain injury and sequential peripheral organ damage.

Traumatic brain injury (TBI) has been found to be associated with certain peripheral organ injuries; however, a few studies have explored the chronological influences of TBI on multiple organs and the systemic effects of therapeutic interventions. Particularly, high-mobility group box 1 (HMGB1) is a potential therapeutic target for TBI; however, its effects on peripheral organs remain unclear. Therefore, this study aimed to determine whether severe TBI can lead to multiple organ injury and how HMGB1 inhibition affects peripheral organs. This study used a weight drop-induced TBI mouse model and found that severe TBI can trigger short-lived systemic inflammation, in the lungs and liver, but not in the kidneys, regardless of the severity of the injury. TBI led to an increase in circulating HMGB1 and enhanced gene expressions of its receptors in every organ. Anti-HMGB1 antibody treatment reduced neuroinflammation but increased inflammation in peripheral organs. This study also found that HMGB1 inhibition appears to have a beneficial role in early neuroinflammation but could lead to detrimental effects on peripheral organs through decreased peripheral immune suppression. This study provides novel insights into the chronological changes in multiple organs due to TBI and the unique roles of HMGB1 between the brain and other organs.

Exosomal miR-4745-5p/3911 from N2-polarized tumor-associated neutrophils promotes gastric cancer metastasis by regulating SLIT2.

Tumor cells remodel the phenotype and function of tumor microenvironment (TME) cells to favor tumor progression. Previous studies have shown that neutrophils in TME are polarized to N2 tumor-associated neutrophils (TANs) by tumor derived factors, thus promoting tumor growth and metastasis, angiogenesis, therapy resistance, and immunosuppression. Exosomes act as critical intercellular messengers in human health and diseases including cancer. So far, the biological roles of exosomes from N2 TANs in gastric cancer have not been well characterized. Herein, we represented the first report that exosomes from N2 TANs promoted gastric cancer metastasis in vitro and in vivo. We found that exosomes from N2 TANs transferred miR-4745-5p/3911 to gastric cancer cells to downregulate SLIT2 (slit guidance ligand 2) gene expression. Adenovirus-mediated overexpression of SLIT2 reversed the promotion of gastric cancer metastasis by N2 TANs derived exosomes. We further revealed that gastric cancer cells induced glucose metabolic reprogramming in neutrophils through exosomal HMGB1 (high mobility group protein B1)/NF-κB pathway, which mediated neutrophil N2 polarization and miR-4745-5p/3911 upregulation. We further employed ddPCR (droplet digital PCR) to detect the expression of miR-4745-5p/3911 in N2 TANs exosomes from human serum samples and found their increased levels in gastric cancer patients compared to healthy controls and benign gastric disease patients. Conclusively, our results indicate that N2 TANs facilitate cancer metastasis via regulation of SLIT2 in gastric cancer cells by exosomal miR-4745-5p/3911, which provides a new insight into the roles of TME cells derived exosomes in gastric cancer metastasis and offers a potential biomarker for gastric cancer diagnosis.

S100A9 and HMGB1 orchestrate MDSC-mediated immunosuppression in melanoma through TLR4 signaling.

BACKGROUND: Immunotherapies for malignant melanoma are challenged by the resistance developed in a significant proportion of patients. Myeloid-derived suppressor cells (MDSC), with their ability to inhibit antitumor T-cell responses, are a major contributor to immunosuppression and resistance to immune checkpoint therapies in melanoma. Damage-associated molecular patterns S100A8, S100A9, and HMGB1, acting as toll like receptor 4 (TLR4) and receptor for advanced glycation endproducts (RAGE) ligands, are highly expressed in the tumor microenvironment and drive MDSC activation. However, the role of TLR4 and RAGE signaling in the acquisition of MDSC immunosuppressive properties remains to be better defined. Our study investigates how the signaling via TLR4 and RAGE as well as their ligands S100A9 and HMGB1, shape MDSC-mediated immunosuppression in melanoma. METHODS: MDSC were isolated from the peripheral blood of patients with advanced melanoma or generated in vitro from healthy donor-derived monocytes. Monocytes were treated with S100A9 or HMGB1 for 72 hours. The immunosuppressive capacity of treated monocytes was assessed in the inhibition of T-cell proliferation assay in the presence or absence of TLR4 and RAGE inhibitors. Plasma levels of S100A8/9 and HMGB1 were quantified by ELISA. Single-cell RNA sequencing (scRNA-seq) was performed on monocytes from patients with melanoma and healthy donors. RESULTS: We showed that exposure to S100A9 and HMGB1 converted healthy donor-derived monocytes into MDSC through TLR4 signaling. Our scRNA-seq data revealed in patient monocytes enriched inflammatory genes, including S100 and those involved in NF-κB and TLR4 signaling, and a reduced major histocompatibility complex II gene expression. Furthermore, elevated plasma S100A8/9 levels correlated with shorter progression-free survival in patients with melanoma. CONCLUSIONS: These findings highlight the critical role of TLR4 and, to a lesser extent, RAGE signaling in the conversion of monocytes into MDSC-like cells, underscore the potential of targeting S100A9 to prevent this conversion, and highlight the prognostic value of S100A8/9 as a plasma biomarker in melanoma.

The role of high mobility group box-1 on the development of diabetes complications: A plausible pharmacological target.

BACKGROUND: Diabetes mellitus has emerged as a pressing global concern, with a notable increase in recent years. Despite advancements in treatment, existing medications struggle to halt the progression of diabetes and its associated complications. Increasing evidence underscores inflammation as a significant driver in the onset of diabetes mellitus. Therefore, perspectives on new therapies must consider shifting focus from metabolic stress to inflammation. High mobility group box (HMGB-1), a nuclear protein regulating gene expression, gained attention as an endogenous danger signal capable of sparking inflammatory responses upon release into the extracellular environment in the late 1990s. PURPOSE: Given the parallels between inflammatory responses and type 2 diabetes (T2D) development, this review paper explores HMGB-1's potential involvement in onset and progression of diabetes complications. Specifically, we will review and update the understanding of HMGB-1 and its inflammatory pathways in insulin resistance, diabetic nephropathy, diabetic neuropathy, and diabetic retinopathy. CONCLUSIONS: HMGB-1 and its receptors i.e. receptor for advanced glycation end-products (RAGE) and toll-like receptors (TLRs) present promising targets for antidiabetic interventions. Ongoing and future projects in this realm hold promise for innovative approaches targeting HMGB-1-mediated inflammation to ameliorate diabetes and its complications.

Aphthous stomatitis - computational biology suggests external biotic stimulus and immunogenic cell death involved.

BACKGROUND: The exact cause of recurrent aphthous stomatitis is still unknown, making it a challenge to develop effective treatments. This study employs computational biology to investigate the molecular basis of recurrent aphthous stomatitis, aiming to identify the nature of the stimuli triggering these ulcers and the type of cell death involved. METHODS: To understand the molecular underpinnings of recurrent aphthous stomatitis, we used the Génie tool for gene identification, targeting those associated with cell death in recurrent aphthous stomatitis. The ToppGene Suite was employed for functional enrichment analysis. We also used Reactome and InteractiVenn for protein integration and prioritization against a PANoptosis gene list, enabling the construction of a protein-protein interaction network to pinpoint key proteins in recurrent aphthous stomatitis pathogenesis. RESULTS: The study's computational approach identified 1,375 protein-coding genes linked to recurrent aphthous stomatitis. Critical among these were proteins responsive to bacterial stimuli, especially high mobility group protein B1 (HMGB1), toll-like receptor 2 (TLR2), and toll-like receptor 4 (TLR4). The enrichment analysis suggested an external biotic factor, likely bacterial, as a triggering agent in recurrent aphthous stomatitis. The protein interaction network highlighted the roles of tumor necrosis factor (TNF), NF-kappa-B essential modulator (IKBKG), and tumor necrosis factor receptor superfamily member 1A (TNFRSF1A), indicating an immunogenic cell death mechanism, potentially PANoptosis, in recurrent aphthous stomatitis. CONCLUSION: The findings propose that bacterial stimuli could trigger recurrent aphthous stomatitis through a PANoptosis-related cell death pathway. This new understanding of recurrent aphthous stomatitis pathogenesis underscores the significance of oral microbiota in the condition. Future experimental validation and therapeutic strategy development based on these findings are necessary.

Metformin lotion promotes scarless skin tissue formation through AMPK activation, TGF-ß1 inhibition, and reduced myofibroblast numbers.

Scar tissue formation following skin wound healing is a challenging public health problem. Skin regeneration and preventing the formation of scar tissue by currently available commercial products are largely ineffective. This study aimed to test the efficacy of a novel topical metformin lotion (ML) in inhibiting scar tissue formation during skin wound healing in rats and to determine the mechanisms of action involved. A 6% ML was prepared in our laboratory. A skin wound healing model in rats was used. The wounded rats were divided into two groups and treated daily for 10 days as follows: Group 1 received a daily application of 50 mg of control lotion, or 0% ML (totaling 100 mg of lotion per rat), and Group 2 received a daily application of 50 mg of 6% ML (totaling 100 mg of 6% ML per rat). Blood samples from the heart of each rat were analyzed for inflammatory markers, HMGB1 and IL-1ß, using ELISA, and immunological and histological analyses were performed on skin tissue sections. ML decreased levels of inflammatory markers HMGB1 and IL-1ß in the serum of rats and inhibited the release of HMGB1 from cell nuclei into the skin tissue matrix. Additionally, ML demonstrated anti-fibrotic properties by enhancing AMPK activity, decreasing the expression of TGF-ß1, reducing the number of myofibroblasts, decreasing the production of collagen III, and increasing the expression of collagen I. ML promotes the regeneration of high-quality skin during wound healing by reducing scar tissue formation. This effect is mediated through the activation of AMPK, inhibition of TGF-ß1, and a decrease in the number of myofibroblasts.

A Glycyrrhizin Derivative with a More Potent Inhibitory Activity against High-Mobility Group Box 1 Efficiently Discovered by Chemical Synthesis Inspired by the Bioconversion Products of an Endophytic Fungus Isolated from Licorice.

Glycyrrhizin (GL) from licorice alleviates intracerebral hemorrhage (ICH) injuries by interacting with high-mobility group box (HMGB) 1, an inflammatory factor. We found that GL is bioconverted by endophyte coexisting with licorice and succeeded in isolating two derivatives. The aim of this study was to identify the compound with more potent HMGB1 inhibitory activity inspired by these GL derivatives. We took advantage of a ketone introduced by an endophyte at the C-3 position and attempted methyl esterification at the C-30 position because it was suggested that the water or lipid solubility of the molecule plays an important role. Among three derivatives synthesized, the product that is both ketonized and esterified showed more potent HMGB1 inhibitory activity than GL in macrophages and significantly improved adverse events occurred in ICH in vivo. These results suggest that modification of the hydrophilicity of GL, particularly at the C-3 and C-30 positions, enhances the HMGB1 inhibitory activity.

High Mobility Group Box 1 and Cardiovascular Diseases: Study of Act and Connect.

Cardiovascular disease is the deadly disease that can result in sudden death, and inflammation plays an important role in its onset and progression. High mobility group box 1 (HMGB1) is a nuclear protein that regulates transcription, DNA replication, repair, and nucleosome assembly. HMGB1 is released passively by necrotic tissues and actively secreted by stressed cells. Extracellular HMGB1 functions as a damage associated molecular patterns molecule, producing numerous redox forms that induce a range of cellular responses by binding to distinct receptors and interactors, including tissue inflammation and regeneration. Extracellular HMGB1 inhibition reduces inflammation and is protective in experimental models of myocardial ischemia/reperfusion damage, myocarditis, cardiomyopathies caused by mechanical stress, diabetes, bacterial infection, or chemotherapeutic drugs. HMGB1 administration following a myocardial infarction followed by permanent coronary artery ligation improves cardiac function by stimulating tissue regeneration. HMGB1 inhibits contractility and produces hypertrophy and death in cardiomyocytes, while also stimulating cardiac fibroblast activity and promoting cardiac stem cell proliferation and differentiation. Maintaining normal nuclear HMGB1 levels, interestingly, protects cardiomyocytes from apoptosis by limiting DNA oxidative stress, and mice with HMGB1cardiomyocyte-specific overexpression are partially protected from cardiac injury. Finally, elevated levels of circulating HMGB1 have been linked to human heart disease. As a result, following cardiac damage, HMGB1 elicits both detrimental and helpful responses, which may be due to the formation and stability of the various redox forms, the particular activities of which in this context are mostly unknown. This review covers recent findings in HMGB1 biology and cardiac dysfunction.

High mobility group box-1 protein promotes astrocytic CCL5 production through the MAPK/NF-κB pathway following spinal cord injury.

Astrocytes act as immune cells that can produce a series of chemokines to attract large numbers of leucocytes to the lesion site, where they contribute to excessive inflammation following spinal cord injury (SCI). However, the relevant regulatory mechanism involved in chemokine production by astrocytes has not been fully elucidated. In the present study, we examined the correlation between C-C motif chemokine ligand 5 (CCL5) and high mobility group box-1 protein (HMGB1) in a T8-T10 spinal cord contusion model. Our results revealed that SCI-induced CCL5 protein levels increased synchronously with the increase in HMGB1. Administration of an HMGB1-neutralizing antibody significantly reduced the protein expression of CCL5 in the context of SCI. An in vitro study revealed that HMGB1 binding with TLR2/4 receptors potently facilitates the production of CCL5 by astrocytes by activating the intracellular ERK/JNK-mediated NF-κB pathway. Furthermore, the HMGB1-induced release of CCL5 from astrocytes is involved in promoting microglia/macrophage accumulation and M1 polarization. The inhibition of HMGB1 activity reduces microglia/macrophage infiltration by decreasing the expression of CCL5 and improves motor functional recovery following SCI. Our results provide insights into the new functions of HMGB1-mediated astrocytic CCL5 production, which elicits inflammatory cell recruitment to the site of injury; this recruitment is associated with excessive inflammation activation. These data may provide a new therapeutic strategy for central nervous system (CNS) inflammation.

IFN-γ induces acute graft-versus-host disease by promoting HMGB1-mediated nuclear-to-cytoplasm translocation and autophagic degradation of p53.

Acute graft-versus-host disease (aGVHD) poses a significant impediment to achieving a more favourable therapeutic outcome in allogeneic hematopoietic stem cell transplantation (allo-HSCT). Our prior investigations disclosed a correlation between p53 down-regulation in CD4+ T cells and the occurrence of aGVHD. Notably, the insufficiency of the CCCTC-binding factor (CTCF) emerged as a pivotal factor in repressing p53 expression. However, the existence of additional mechanisms contributing to the reduction in p53 expression remains unclear. Interferon (IFN)-γ, a pivotal proinflammatory cytokine, assumes a crucial role in regulating alloreactive T-cell responses and plays a complex part in aGVHD development. IFN-γ has the capacity to induce autophagy, a vital catabolic process facilitating protein degradation, in various cell types. Presently, whether IFN-γ participates in the development of aGVHD by instigating the autophagic degradation of p53 in CD4+ T cells remains an unresolved question. In the present study, we demonstrated that heightened levels of IFN-γ in the plasma during aGVHD promoted the activation, proliferation, and autophagic activity of CD4+ T cells. Furthermore, IFN-γ induced the nuclear-to-cytoplasm translocation and autophagy-dependent degradation of p53 in CD4+ T cells. The translocation and autophagic degradation of p53 were contingent upon HMGB1, which underwent up-regulation and translocation from the nucleus to the cytoplasm following IFN-γ stimulation. In conclusion, our data unveil a novel mechanism underlying p53 deficiency in CD4+ T cells among aGVHD patients. This deficiency is induced by IFN-γ and relies on autophagy, establishing a link between IFN-γ, HMGB1-mediated translocation, and the autophagic degradation of p53.

Taurochenodeoxycholic acid ameliorates the Staphylococcus aureus infection-induced acute lung injury through toll-like receptor 2 in mice.

Acute lung injury (ALI) is a significant clinical problem associated with high morbidity and mortality. Inflammation induced by gram-positive bacterial pathogens, specifically Staphylococcus aureus (S. aureus), plays a major role in ALI development and other infectious diseases. Taurochenodeoxycholic acid (TCDCA) exhibits diverse biological activities and pharmacological effects. Nevertheless, the potential preventive and therapeutic effects of TCDCA and the underlying mechanism in the ALI induced by S. aureus infection remain poorly understood. Our results showed that the TCDCA (0.1 µg/g) had a beneficial effect on lung damage in mice infected with S. aureus. Specifically, TCDCA could lead to a reduction in pulmonary focal or diffuse oedema and a decrease in the infiltration of neutrophils in the S. aureus-infected lungs. We observed that TCDCA could significantly down-regulate the expression of HMGB1 in lung from S. aureus-infected mice. Furthermore, TCDCA could attenuate the production of inflammatory mediators in lungs and serum from S. aureus-infected mice. This finding further supported the notion that TCDCA potentially protects against tissue injury. In addition, TCDCA regulated the secretion of the proinflammatory cytokine, the activation of MAPK and NF-κB signaling pathways, and the activation of TLR2 in macrophages. Notably, TCDCA might reduce the secretion levels of inflammatory mediators and lung damage through the TLR2 in S. aureus-infected macrophages or mice. Altogether, TCDCA shows promise as a potential drug for preventing and treating ALI by modulating or inhibiting inflammatory mediators through TLR2.

Remimazolam ameliorates postoperative cognitive dysfunction after deep hypothermic circulatory arrest through HMGB1-TLR4-NF-κB pathway.

BACKGROUND: Postoperative cognitive dysfunction (POCD) is a complication of deep hypothermic circulatory arrest (DHCA). Various amounts of neurologic dysfunctions have been shown after DHCA, which has often been attributed to systemic inflammatory response syndrome and cerebral ischemia/reperfusion injury. Remimazolam is one of the commonly used anesthetic drugs with protective actions against inflammatory diseases, such as sepsis and cerebral ischemia/reperfusion injury. Here, we determined the protective effect and potential mechanism of action of remimazolam against neuronal damage after DHCA. METHODS: A rat model of DHCA was established, and a gradient dosage of remimazolam was administered during cardiopulmonary bypass (CPB). The cognitive function of rats was evaluated by Morris water maze. Hematoxylin and eosin and TUNEL staining were performed to assess hippocampus tissue injury and neuronal apoptosis. Inflammatory cytokines concentration were analyzed by enzyme-linked immunosorbent assay. The protein expression was analyzed using automated electrophoresis western analysis and immunohistochemical analysis. RESULTS: The appropriate dosage of remimazolam reduced histologic injury, neuronal apoptosis, microglia activation, and secondary inflammatory cascades, as well as the downregulation of the expression of the HMGB1-TLR4-NF-κB pathway after DHCA, improved the memory and learning abilities in DHCA rats. Further, administration of a TLR4 antagonist TAK-242 had a similar effect to remimazolam, while the TLR4 agonist LPS attenuated the effect of remimazolam. CONCLUSIONS: Remimazolam could ameliorate POCD after DHCA through the HMGB1-TLR4-NF-κB signaling pathway.