HMGB1 Research Articles

Pathophysiological role of high mobility group box-1 signaling in neurodegenerative diseases.

Nucleocytoplasmic translocation of HMGB1 (high mobility group box-1) plays a significant role in disease progression. Several methods contribute to the translocation of HMGB1 from the nucleus to the cytoplasm, including inflammasome activation, TNF-α signaling, CRM1-mediated transport, reactive oxygen species (ROS), JAK/STAT pathway, RIP3-mediated p53 involvement, XPO-1-mediated transport, and calcium-dependent mechanisms. Due to its diverse functions at various subcellular locations, HMGB1 has been identified as a crucial factor in several Central Nervous System (CNS) disorders, including Huntington's disease (HD), Parkinson's disease (PD), and Alzheimer's disease (AD). HMGB1 displays a wide array of roles in the extracellular environment as it interacts with several receptors, including CXCR4, TLR2, TLR4, TLR8, and RAGE, by engaging in these connections, HMGB1 can effectively regulate subsequent signaling pathways, hence exerting an impact on the progression of brain disorders through neuroinflammation. Therefore, focusing on treating neuroinflammation could offer a common therapeutic strategy for several disorders. The objective of the current literature is to demonstrate the pathological role of HMGB1 in various neurological disorders. This review also offers insights into numerous therapeutic targets that promise to advance multiple treatments intended to alleviate brain illnesses.

Ro 90-7501 suppresses colon cancer progression by inducing immunogenic cell death and promoting RIG-1-mediated autophagy.

Colon cancer is one of the leading causes of cancer-related mortality worldwide. Current treatments, including surgery, chemotherapy, and radiation therapy, often have limited efficacy due to tumor heterogeneity and resistance mechanisms. Therefore, there is a critical need for novel therapeutic strategies that can enhance the immune response against colon cancer cells while promoting their efficient clearance. In this study, we investigated the anti-tumor effects of Ro 90-7501, a specific small molecule, in colon cancer cell lines (HCT8 and SW480) and in vivo models. MTS, EdU, Scratch Wound and Transwell assays were performed to detect the cell proliferation and metastasis. Additionally, flow cytometry and immunofluorescence staining were used to analyze changes in apoptosis and necrosis. Furthermore, we examined its ability to induce immunogenic cell death (ICD) and promote retinoic acid-inducible gene I (RIG-I)-mediated autophagy. The expression levels of key molecules involved in ICD and autophagy were assessed using Western blot analysis, immunofluorescence staining, and enzyme-linked immunosorbent assay (ELISA). Our findings demonstrated that Ro 90-7501 significantly suppressed colon cancer cell proliferation and metastasis, inducing apoptosis and necrosis. Mechanistically, Ro 90-7501 triggered ICD by upregulating the exposure of calreticulin (CRT) on the cell surface and increasing the release of high mobility group box 1 (HMGB1) and extracellular ATP levels. Concurrently, it promoted RIG-I-mediated autophagy via the MAVS-TRAF6 signaling axis, evidenced by increased expression of autophagy-related genes, such as microtubule-associated protein 1 light chain 3 (LC3) and Beclin 1 proteins, coupled with a reduction in P62 protein. Additionally, Ro 90-7501 treatment activated the RIG-I-MAVS-TRAF6 signaling axis in colon cancer cells. Furthermore, Ro 90-7501 enhanced the secretion of pro-inflammatory cytokines, such as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNFα), thereby activating the immune response. In conclusion, Ro 90-7501 exhibits potent anti-tumor activity against colon cancer by inducing ICD and promoting RIG-I-mediated autophagy. These results suggest that Ro 90-7501 may serve as a promising therapeutic candidate for colon cancer treatment by enhancing both intrinsic cellular processes and adaptive immune responses. Further studies are warranted to elucidate the detailed mechanisms underlying these effects and to evaluate its therapeutic potential in clinical settings.

Echinochrome A inhibits HMGB1-induced vascular smooth muscle cell migration by suppressing osteopontin expression.

Echinochrome A (Ech A) isolated from marine organisms is a therapeutic effector for various cardiovascular diseases, but its precise mechanisms are unclear. This study identified the role and mechanisms mediating the effects of Ech A on the migration of vascular smooth muscle cells (VSMCs) induced by high-mobility group box 1 (HMGB1). Compared to the control cells, the migration of VSMCs stimulated with HMGB1 (100 ng/ml) was markedly increased, which was significantly attenuated in cells pretreated with MPIIIB10 (100 ng/ml), a neutralizing monoclonal antibody for osteopontin (OPN). In VSMCs stimulated with HMGB1, the increased expression of OPN mRNA and protein was accompanied by an increased OPN promoter activity. In reporter gene assays using OPN promoter-luciferase constructs, the promoter region 538-234 bp of the transcription start site containing the binding sites for activator protein 1 (AP-1) was shown to be responsible for the increased transcriptional activity by HMGB1. In addition, the binding activity of AP-1 was increased in HMGB1-stimulated cells, highlighting the pivotal role of AP-1 on OPN expression in HMGB1-stimulated VSMCs. An examination of the vascular effects of Ech A showed that the increased AP-1 binding/promoter activities and OPN expression induced by HMGB1 were attenuated in cells pretreated with Ech A (3 or 10 μM). Similarly, Ech A inhibited HMGB1-induced VSMC migration in a concentration-dependent manner. These findings suggest that Ech A inhibits VSMC migration by suppressing OPN expression. Hence, Ech A is suggested as a potential therapeutic strategy for vascular remodeling in the injured vasculatures.

The Immunohistochemical and Bioinformatics Analysis of the Placental Expressions of Vascular Cell Adhesion Protein 1 (VCAM-1) and High Mobility Group Box 1 (HMGB1) Proteins in Gestational Diabetic Mothers.

We aimed to examine both the expression levels of high mobility group box 1 (HMGB1) and vascular cell adhesion molecule-1 (VCAM-1) proteins in the placentas of pregnant women with gestational diabetes mellitus (GDM) and control groups by immunohistochemical (IHC) method. An experimental case-control study was conducted, including 40 pregnant women complicated with GDM and 40 healthy pregnant women. Placental tissues obtained following cesarean delivery were subjected to routine tissue monitoring. The placental sections were stained with VCAM-1 and HMGB1 immunostains and subjected to IHC examination under a light microscope. H-score (HS) was used to evaluate the results of IHC staining by semi-quantitative analysis. Pathway analysis in Cytoscape software identified GDM-associated proteins within HMGB1 and VCAM-1 interaction networks, followed by GO analysis to explore associated biological processes. Placental HGMB1 expression was significantly increased in the GDM group compared to the control group (p<0.001). However, placental VCAM-1 expression was found to be statistically similar in GDM and control groups (p=0.584). The shared 19 proteins were identified between HMGB1 and GDM, and 13 between VCAM-1 and GDM, with notable GO biological process terms such as immune system activation for HMGB1 and interleukin-6 regulation for VCAM-1 associated with GDM. We consider that GDM-related inflammation and oxidative stress may contribute to tissue damage and inflammation by increasing placental HMGB1 expression. The blockade of HMGB1 and its receptors might represent a promising therapeutic approach to control inflammation in GDM. Understanding the distinct roles of HMGB1 and VCAM-1 may provide valuable insights for the development of targeted therapies aimed at mitigating the inflammatory processes associated with GDM and improving maternal and fetal outcomes.

Serum High Mobility Group Box 1 (HMGB1) Protein Levels and Cognitive Function in Epilepsy Patients: A Cross-Sectional Study

Background: Epilepsy is a neurological disease with a high incidence rate. Cognitive decline is one of the consequences of recurrent seizures. Neuroinflammation is closely related to the development of epilepsy and cognitive impairment. An increase in the expression and translocation of High Mobility Group Box 1 (HMGB1) from the nucleus to the extracellular space has been observed in epilepsy patients and experimental animal models. This study aimed to investigate the relationship between serum HMGB1 levels and cognitive function in epilepsy patients. Methods: This cross-sectional observational study involved 45 epilepsy patients. Cognitive function was assessed using the Indonesian version of the Montreal Cognitive Assessment (MoCA-Ina), and serum HMGB1 levels were measured using the ELISA technique. The relationship between cognitive function and HMGB1 levels was analyzed using the Kruskal-Wallis test, with a significance level set at p &lt; 0.05. Results: The mean age of the participants was 28.5 years, with a higher proportion of females. The mean serum HMGB1 level was 22.6 ng/ml. No significant relationship was found between serum HMGB1 levels and cognitive function in epilepsy patients (p = 0.188). Conclusion: Serum HMGB1 protein levels were not associated with cognitive function in this sample of epilepsy patients.

Abstract 4146302: NETosis Attenuating Nanoprobe Improves Survival after Cardiac Arrest

NETosis, the process of neutrophil cell death due to the formation and release of neutrophil extracellular traps (NETs) has been implicated in the pathogenesis of heart disease. NETs are composed of immunogenic DNA fragments and citrullinated histones. The role of NETosis in the context of cardiac arrest and resuscitation (CA/R) is however unknown. We previously reported the development of a Dextran-Thiazole Orange (DTO) nanoprobe, with nanomolar affinity for nucleic acids, that exerts acute anti-inflammatory effects and reduces ischemia-reperfusion injury in mice. We aimed here to determine whether the DTO nanoprobe would also bind to the nucleic acid in NETS, whether DTO could attenuate the intensity of NETosis, and whether this would improve outcomes and survival after cardiac arrest. C57Bl6 mice were arrested for 8 minutes before resuscitation. DTO or unmodified dextran (vehicle control) was injected at the time of resuscitation, and again 4 hours later (n=38 mice). Survival and neurological function were scored daily. Time-domain resolved (lifetime) and conventional fluorescence imaging was performed at 4 hours after resuscitation in 6 additional mice injected with DTO. NETosis was evaluated by protein blot in the hearts of cardiac arrest mice injected with DTO or control. DTO significantly (p&lt;0.05) improved 10-day survival (Fig. A), mean survival (from 4 to 7 days, Fig. B), and neurological function (Fig. C) following CA/R. Lifetime imaging (Fig. D), but not conventional fluorescence imaging (Fig. E) revealed the presence of DTO in the injured heart, liver and kidneys. In the heart, DTO signal was significantly increased in CA/R compared to sham mice injected with DTO or CA/R mice injected with control dextran (Fig. F). Citrullinated H3 and HMGB-1 (High mobility group box 1, a chromatin protein) were both upregulated in CA/R, and were significantly attenuated by DTO injection (Fig. G-I). We show for the first time that NETosis plays a key role in cardiac arrest and resuscitation. DTO is capable of detecting NETosis as well as attenuating it, likely via a reduction in HMGB-1 activity. The modulation of NETosis may provide a new avenue to improve survival after cardiac arrest.

Effects of pericapsular nerve group block on early postoperative cognitive function in older people undergoing hip arthroplasty: a randomized controlled clinical trial.

Pericapsular nerve group (PENG) block has emerged as a reliable analgesia technique for hip arthroplasty (HA). However, the effects of PENG block on perioperative neurocognitive disorder (PND) after HA has not yet been assessed. The present study aimed to investigate the effects of PENG block on early postoperative cognitive function in older people undergoing hip arthroplasty. Sixty older patients undergoing HA under spinal anesthesia were randomly assigned to group P (n = 30) receiving PENG block with ropivacaine and patient-controlled intravenous analgesia (PCIA) pump with sufentanil after surgery or group C (n = 30) only receiving PCIA pump with sufentanil after surgery. The primary outcome was the Mini-Mental State Examination (MMSE) score at 7 days postoperatively. Secondary outcomes consisted of the incidence of PND 7 days postoperatively, the static VAS pain scores at 6, 12, 24, and 48h postoperatively; cumulative sufentanil consumption and the requirement of rescue analgesia during the 0-24h period after surgery; quality of recovery-15 (QoR-15) scale scores at 24h postoperatively; and the plasma levels of high mobility group box protein 1 (HMGB1) preoperatively and 1day after surgery, and adverse events. After surgery, the PENG block group had higher MMSE score than the control group at 7 days postoperatively (27.0 ± 1.8 vs. 26.1 ± 1.7, P = 0.048), with a mean difference of 0.9 (95%CI, 0.1-0.9). The incidence of PND at 7 days postoperatively was 6.7% in group P, lower than that of 30% in group C (P = 0.044). In group P, the static VAS scores at 6, 12, and 24h postoperatively were significantly lower than those in group C (all P < 0.05). Compared with group C, the cumulative sufentanil consumption and the number of patients required rescue analgesia during the 0-24h period after surgery were significantly lower in group P (all P < 0.05). The scores of QoR-15 scale were higher in group P at 24h postoperatively than those in group C (P < 0.05). Patients in group P showed lower plasma levels of HMGB1 than group C at 1day after surgery (P < 0.05), and the rate of complications didn't differ between both groups. Older people undergoing HA receiving a PENG block for perioperative analgesia experience improved early postoperative cognitive function, reduced postoperative pain, higher quality of recovery, and less postoperative inflammatory response. Chictr.org.cn identifier ChiCTR2200061055 (Date of registry: 15/06/2022, prospectively registered).

Neutrophil extracellular traps formation is associated with postoperative complications in congenital cardiac surgery.

Pediatric patients with congenital heart disease (CHD) often require surgical repair using cardiopulmonary bypass. Despite advancements, mortality and complication rates remain significant. We prospectively examined 101 patients undergoing congenital cardiac surgery, identifying a mortality rate of 4.0% and a complication rate of 31.6%. Neonates and infants exhibitedmultiple complicationsmore frequently. Prolonged bypass time was significantly associated with complications, with each additional 30 min increasing the odds by 1.46 times (95% CI 1.01-2.10, p = 0.042). We further investigated the involvement of damage-associated molecular pattern (DAMP) molecules by proteomics and ELISA. Plasma levels of DAMPs, including histones and high mobility group box 1 (HMGB1), were significantly elevated in the complication group. As these molecules target Toll-like receptor (TLR)2 and TLR4, mRNA expression of TLR2 and TLR4 in neutrophils was upregulated in the complication group. In vitro and in vivo analyses demonstrated that histones and HMGB1 induced the formation of neutrophil extracellular traps (NETs). This finding aligned with greater NETs formation observed at the end of CPB and during the postoperative period in neonates and infants who developed postoperative complications. Targeting NETs and associated DAMPs may provide a novel therapeutic approach to mitigate complications in this patient population.

CSIG-30. EXPLORING THE ROLE OF CAPICUA (CIC) IN RESISTANCE MECHANISMS OF MEK INHIBITORS IN GLIOBLASTOMA

Abstract Glioblastoma multiforme (GBM) is the most common and fatal primary brain tumor, resistant to conventional therapy. Despite its heterogeneous nature, a key feature of GBM is aberrant kinase signaling. Specifically, hyperactivation of receptor tyrosine kinases (RTK) and their downstream tumorigenic effectors Ras/MEK/Extracellular Signal Regulated Kinase (ERK) pathway are attributed to the aggressive nature of GBM. Capicua (CIC) is a High Mobility Group (HMG) box transcriptional repressor that directly binds to DNA and counteracts the transcription of genes typically expressed only in response to RTK activation such as oncogenic transcription factors ETV1/4/5. Hyperactive MEK/ERK signaling in GBM causes CIC degradation. The mechanism of CIC’s repressor function is not well understood, however, transcriptional repressors (like CIC) typically form co-repressor complexes to repress target genes. We discovered a novel interaction between CIC and the transcriptional regulator yin yang 1 (YY1), a context-dependent transcription factor that can repress or activate gene expression. We uncovered that 90-kDa ribosome S6 protein kinase (p90RSK), a downstream effector of ERK and a known CIC regulator, mediates the CIC/YY1 interaction. Interestingly, we found re-activation of p90RSK following MEK/ERK inhibition implicating p90RSK in the resistance mechanism of RTK/MEK/ERK inhibition in GBM. We hypothesize that p90RSK inhibition will stabilize the CIC/YY1 co-repressor complex and re-sensitize towards MEK/ERK inhibition. Patient-derived glioma stem-like cells (GSCs) were treated with increasing doses of BI-D1870 or LJI308 (p90RSK inhibitors) with and without selumetinib (MEK inhibitor) and various functional assays were performed to examine the effect of p90RSK inhibition on the CIC/YY1 complex and sensitization to MEK/ERK inhibition. Treatment with BI-D1870 and LJI308 markedly reduced viability and mRNA expression of ETV1/4/5 indicating that p90RSK inhibition may mediate CIC /YY1 DNA binding ability. Importantly, inhibiting p90RSK sensitized GSCs to MEK/ERK inhibition. These results highlight the importance of downstream p90RSK inhibition in stabilizing CIC/YY1 repressor complex function and sensitizing cells to RTK/MEK/ERK inhibition.

H2 protects H9c2 cells from hypoxia/reoxygenation injury by inhibiting the Wnt/CX3CR1 signaling pathway.

Myocardial ischemia-reperfusion injury is a severe cardiovascular disease, and its treatment and prevention are crucial for improving patient prognosis and reducing the economic burden. This study aimed to explore the impact of hydrogen (H2) on hypoxia/reoxygenation (H/R) injury in H9c2 cells (derived from rat embryonic heart tissue) induced by hydrogen peroxide (H2O2) and to elucidate its underlying mechanism. An H/R injury model was established in H9c2 cells via exposure to 15 μM H2O2 for 3 hours, followed by incubation in a 5% CO2 atmosphere at 37°C for 24 hours. Then, the cells were treated with H2 (50%) for 6, 12 or 24 hours. The results demonstrated that H9c2 cells exposed to H2O2 and subjected to H/R injury presented a marked decrease in the cell survival rate, accompanied by severe morphological alterations, such as curling and wrinkling, and elevated lactate dehydrogenase levels. Notably, H2 mitigated H/R injury induced by H2O2 in a time-dependent manner, improving the morphological damage observed in H9c2 cells and decreasing lactate dehydrogenase levels. Compared with the model group, treatment with H2 increased the activities of antioxidant enzymes, including catalase, superoxide dismutase, and glutathione peroxidase, while concurrently reducing the level of malondialdehyde, an indicator of cellular damage. Furthermore, H2 treatment downregulated the expression of inflammatory cytokines and inflammatory-related factors, specifically interleukin-6, high-mobility group box 1, tumor necrosis factor-alpha, and Toll-like receptor 4, in H9c2 cells post-H/R injury. Furthermore, H2 treatment resulted in a marked decrease in the expression levels of proteins associated with the Wnt/C-X3-C-motif receptor 1 signaling pathway, such as β-catenin, glycogen synthase kinase-3 beta, adenomatous polyposis coli, and Wnt and C-X3-C-motif receptor 1. This observation suggests a potential mechanism for its protective effects against H/R injury. Therefore, H2 exerts a protective effect against H/R injury in H9c2 cells induced by H2O2, potentially by inhibiting the activated Wnt/C-X3-C-motif receptor 1 signaling pathway. This inhibition, in turn, prevents the generation of oxidative stress, inflammatory cytokines, and inflammation-associated factors.

Evaluation of the cell death markers for aberrated cell free DNA release in high altitude pulmonary edema.

The effect of high altitude (HA, altitude >2500 m) can trigger a maladaptive response in unacclimatized individuals, leading to various HA illnesses such as high altitude pulmonary edema (HAPE). The present study investigates circulating cell free (cf) DNA, a minimally invasive biomarker that can elicit a pro-inflammatory response. Our earlier study observed altered cfDNA fragment patterns in HAPE patients and the significant correlation of these patterns with peripheral oxygen saturation levels. However, the unclear release mechanisms of cfDNA in circulation limit its characterization and clinical utility. The present study not only observed a significant increase in cfDNA levels in HAPE patients (27.03 ± 1.37 ng/ml; n = 145) compared to healthy HA sojourners (controls, 14.57 ± 0.74 ng/ml; n = 65) and highlanders (HLs, 15.50 ± 0.8 ng/ml; n = 34) but also assayed the known cell death markers involved in cfDNA release at HA. The study found significantly elevated levels of the apoptotic marker, annexin A5, and secondary necrosis or late apoptotic marker, High mobility group box 1, in HAPE patients. In addition, we observed ahigher oxidative DNA damage marker, 8-hydroxy-2'-deoxyguanosine, in HAPE compared to controls, suggestive of the role of oxidative DNA status in promoting the inflammatory potential of cfDNA fragments and their plausible role in manifesting HAPE pathophysiology. Extensive in vitro future assays can confirm theimmunogenic role of cfDNA fragments that may act as a danger-associated molecular pattern and associate with markers of cellular stresses in HAPE.

Sustained Protraction Increases Lengthening of the Mandibular Condylar Process Whilst Changes Its Growth Direction in a Rat Model.

In Class II elastics treatment, the mandible is subject to sustained protraction. The study aimed to investigate the morphological and histological changes resulting from sustained mandibular protraction, through establishment of a novel model in rat. Forty-eight 4-week-old male Sprague-Dawley rats were randomly divided into three groups, including the 50 and 100 cN protraction groups, and the control. In the two protraction groups, NiTi coil springs were fixed between the metal bands on the maxillary incisors and mandibular molars to pull the mandible forward. CBCT scans were taken immediately before (T0), 2 weeks (T1) and 4 weeks (T2) after the traction. Histological and immunohistochemical analyses were performed at T1 and T2. Increase of the condylar process length and angular process length were significantly larger in the two protraction groups than that in the control; however, the condylar process angle (∠CPA) was significantly reduced by the protraction at T2, leading to decreased condylar height. The protraction decreased the condylar cartilage thickness at T1, which recovered to the control level at T2, with no significant changes detected in the expression of SRY-related high mobility group-box gene 9 (SOX9) and type II collagen (COL II), two chondrogenic markers. The established rat model is manoeuvrable and reliable, which exerts sustained and measurable mandibular protraction. The sustained protraction increases the lengthening of the mandibular condylar process, but alters its growth direction by causing it to turn downwards.

Ameliorative effect of rutecarpine supplementation against cisplatin-induced nephrotoxicity in rats via inhibition of monocyte chemoattractant protein-1, intercellular adhesion molecule-1, high-mobility group box 1, and nuclear factor kappa B.

Cisplatin, the pioneering heavy metal compound, stands out as a potent drug for the treatment of various solid tumors. However, its clinical utility is hampered by notable toxicity and adverse effects, particularly nephrotoxicity. The potency of rutecarpine, a phytochemical, in mitigating cisplatin-induced nephrotoxicity was assessed in the present study. In this experimental setup, healthy male Wistar rats were grouped into four and Group I rats served as the control group, receiving only vehicle control. Group II rats were subjected to cisplatin treatment alone, administered intraperitoneally at a dosage of 7mg/kg body weight on the 19th, 20th, and 21st days. Group III and IV rats were orally administered with rutecarpine at doses of 10 and 20mg/kg body weight, respectively, starting from Day 1 and continuing daily for 21 days. Additionally, they were injected intraperitoneally with cisplatin at the same dosage and schedule as Group II. Relative kidney weight and renal biochemical markers blood urea nitrogen, lactate dehydrogenase, serum urea, and creatinine were measured to assess rutecarpine inhibitory potency against cisplatin toxicity. Markers of oxidative damage and antioxidants levels were quantified in the ruteacarpine- and cisplatin-treated rats. The study investigated the anti-inflammatory property of rutecarpine in cisplatin-induced nephrotoxicity by analyzing inflammatory cytokines. Renal tissue levels of monocyte chemoattractant protein-1, intercellular adhesion molecule-1, high-mobility group box 1, and nuclear factor kappa B, key markers of nephrotoxicity, were quantified to assess rutecarpine's potential to mitigate cisplatin-triggered damage. Histopathological examinations were performed to confirm the impact of rutecarpine against cisplatin-induced nephrotoxicity. Treatment with rutecarpine notably reduced renal biochemical markers, prevented renal edema, and attenuated oxidative stress-induced damage in cisplatin-treated rats. Both inflammatory and nephrotoxicity markers showed significant decreases in rats treated with rutecarpine along with cisplatin. Histological analysis affirmed that rutecarpine pretreatment effectively prevented cisplatin-induced nephrotoxicity. The study findings demonstrate that rutecarpine ameliorates cisplatin-triggered nephrotoxicity through its antioxidant and anti-inflammatory properties, suggesting that rutecarpine supplementation alongside cisplatin treatment could potentially reduce nephrotoxicity in cancer patients.

Targeting high-mobility-group-box-1-mediated inflammation: a promising therapeutic approach for myocardial infarction.

Myocardial ischemia, resulting from coronary artery blockage, precipitates cardiac arrhythmias, myocardial structural changes, and heart failure. The pathophysiology of MI is mainly based on inflammation and cell death, which are essential in aggravating myocardial ischemia and reperfusion injury. Emerging research highlights the functionality of high mobility group box-1, a non-histone nucleoprotein functioning as a chromosomal stabilizer and inflammatory mediator. HMGB1's release into the extracellular compartment during ischemia acts as damage-associated molecular pattern, triggering immune reaction by pattern recognition receptors and exacerbating tissue inflammation. Its involvement in signaling pathways like PI3K/Akt, TLR4/NF-κB, and RAGE/HMGB1 underscores its significance in promoting angiogenesis, apoptosis, and reducing inflammation, which is crucial for MI treatment strategies. This review highlights the complex function of HMGB1 in the pathogenesis of myocardial infarction by summarizing novel findings on the protein in ischemic situations. Understanding the mechanisms underlying HMGB1 could widen the way to specific treatments that minimize the severity of MI and enhance patient outcomes.

Early anti-inflammatory polarization of macrophages ameliorates post-surgical inflammation and osseointegration around titanium implants in mice

Dental implants are considered a superior option for the replacement of missing teeth. However, the invasive nature of the surgical procedure often results in significant postoperative inflammation, and the prolonged healing period of 3 to 6 months presents a notable disadvantage. High mobility group box 1 (HMGB1) is a critical mediator of acute inflammation following surgical injury, which can hinder the onset of osseointegration. This study aims to examine whether the inhibition of HMGB1 can mitigate acute inflammation and subsequently enhance osseointegration. The findings indicate that HMGB1 inhibition markedly reduces inflammation and promotes bone repair in murine models. Further in vitro investigations into the regulatory mechanisms of HMGB1 in macrophages reveal its role in increasing Yes-associated protein (YAP) activity, which contributes to pro-inflammatory polarization. Additionally, conditioned media derived from macrophages influenced by HMGB1 significantly impair the migratory and osteogenic capabilities of bone marrow-derived mesenchymal stem cells, which are essential for bone regeneration. In vivo experiments further validate that the administration of exogenous HMGB1 exacerbates postoperative acute inflammation and obstructs osseointegration. The study concludes that inhibiting HMGB1 fosters an anti-inflammatory polarization of macrophages, leading to diminished postoperative acute inflammation and expedited osseointegration around dental implants in mice.

Glucocorticoids induce HMGB1 release in primary cultured rat cortical microglia

Stress, a risk factor for major depressive disorder and Alzheimer disease, leads to the release of high-mobility group box-1 (HMGB1) protein, which in turn causes neuroinflammation. The mechanism underlying stress-induced HMGB1 release is unknown, but stress-associated glucocorticoids could be involved. Primary cultured rat cortical microglia and neurons were treated with corticosterone, a stress-associated glucocorticoid, and HMGB1 release was measured by ELISA and western blotting to test this hypothesis. With corticosterone treatment, significant HMGB1 was released in microglia but not in neuronal cell cultures. HMGB1 mRNA expression and HMGB1 protein expression in microglia were not affected by corticosterone treatment. Thus, the source of extracellular HMGB1 released into the medium is likely to be existing nuclear HMGB1 rather than newly synthesized HMGB1. Corticosterone-induced HMGB1 release in microglia culture was significantly attenuated by blocking glucocorticoid receptors but not mineralocorticoid receptors. Dexamethasone, a selective glucocorticoid receptor agonist, and dexamethasone-bovine serum albumin (BSA), a membrane-impermeable glucocorticoid receptor agonist used to confirm the membrane receptor-mediated effects of glucocorticoids, increased the release of HMGB1. Immunocytochemistry showed that HMGB1 translocated from the nucleus to the cytoplasm following dexamethasone or dexamethasone-BSA treatment through glucocorticoid receptors. The present findings suggest that glucocorticoids stimulate microglial membrane glucocorticoid receptors and trigger cytoplasmic translocation and extracellular release of nuclear HMGB1. Thus, under stress conditions, glucocorticoids induce microglial HMGB1 release, leading to a neuroinflammatory state that could mediate neurological disorders.

Effect of high mobility group box 1 pathway inhibition on gene expression in the prefrontal cortex of mice exposed to alcohol

The high mobility group box 1 (HMGB1) pathway plays a pivotal role in the development of alcohol-induced brain injury. Glycyrrhizinic acid (GlyA) is widely regarded as an inhibitor of HMGB1. The objective is to investigate the impact on gene expression in the prefrontal cortex,we sequenced the transcriptome in control, alcohol-exposed, and HMGB1-inhibited groups of mice. We verified our findings by real-time quantitative PCR (qRT-PCR). An alcohol exposure model was established in mice by intraperitoneal injection of alcohol. Transcriptome sequencing and bioinformatics analyses were performed on prefrontal cortex tissue. Kyoto Encyclopedia of Genes and Genomes analysis was performed to identify pivotal pathways of differentially expressed genes. The role of relevant genes was verified by qRT-PCR. Expression of genes involved in the neuroactive ligand-receptor interaction pathway exhibited an increase in mice from the alcohol-exposed group.However, there were no significant differences observed in the expression of these genes between control and those receiving an intraperitoneal injection of alcohol along with a HMGB1 inhibitor. Mice in the alcohol-exposed group showed increased gene expression of Cysltr2, Chrna6, Chrna3, Chrnb4, and Pmch. Expression of these genes was decreased in mice injected with HMGB1 inhibitor. Our study demonstrates that alcohol primarily influences gene expression in the prefrontal cortex of mice through the neuroactive ligand-receptor interaction pathway. HMGB1 inhibitor effectively inhibited the expression of this pathway. This study provides a novel route for drug development in alcohol-induced brain injury.

Hepatoprotective effects of the xanthine oxidase inhibitor Febuxostat against thioacetamide-induced liver injury in rats: The role of the Nrf2/ HO-1 and TLR4/ NF-κB pathways

Experimental models of liver injury have been established utilizing thioacetamide (TAA), a classic liver toxic chemical that causes organ damage via oxidative stress and inflammatory induction. This study examined the impact of Febuxostat (a xanthine oxidase inhibitor; Febu, 10–15 mg/kg, orally) against TAA (500 mg/kg, i.p.) -induced liver injury in rats.Febu significantly attenuated TAA-induced alterations in liver function parameters, in addition to promoting hepatic antioxidant effects through a significant elevation of Heme-oxygenase-1(HO-1), nuclear factor erythroid 2-related factor2 (Nrf2), reduced glutathione (GSH) and superoxide dismutase (SOD) levels and reduction in hepatic malondialdehyde (MDA) content. Moreover, Febu improved the hepatic anti-inflammatory status by increasing the anti-inflammatory cytokine Interleukin (IL-10) level and reducing the levels of the pro-inflammatory cytokines (Nuclear factor kappa B (NF-κB), IL-1β, high-mobility group box1 (HMGB1), receptor for advanced glycation end products (RAGE), and toll-like receptor4 (TLR4) levels, in addition to suppressing the increased protein and mRNA expression levels of tumor necrosis factor alpha (TNF-α) and IL-6, hepatic expression of TNF-α and activated mitogen-activated protein kinases (p-JNK/p-p38 MAPK). Histopathologically, Febu markedly normalized TAA-induced alteration in liver sections. In conclusion, Febu, in a dose-dependent fashion, refines TAA-induced hepatotoxicity by enhancing antioxidant capabilities and decreasing inflammatory signals.

FS2 encodes an ARID-HMG transcription factor that regulates fruit spine density in cucumber

Fruit spine density is an important commercial trait for cucumber (Cucumis sativus L.). However, most North China-type cucumbers, which are grown over large areas, have a dense-spine phenotype, which directly affects the appearance quality, storage, and transportation of fruits. Here, we isolated a novel few spines mutant (fs2) from the wild-type (WT) inbred line WD1, a North China-type cucumber with high density fruit spines, by ethyl methanesulfonate (EMS) mutagenic treatment. Genetic analysis revealed that the phenotype of fs2 was controlled by a single recessive nuclear gene. We fine-mapped the fs2 locus using F2 and BC1 populations (1802 and 420 individuals, respectively) and showed that the candidate gene of FS2 (Csa4G652850) encoded an ARID-HMG transcription factor containing an A/T-rich interaction domain (ARID) and a high mobility group box domain (HMG). One SNP (C to T) and one InDel (a 40-bp deletion) in the coding region of FS2 resulted in amino acid variation and premature translation termination in the fs2 mutant, respectively. FS2 was highly expressed in the apical buds and young ovaries. In addition, the experiments suggest that FS2 participates in the regulation of fruit spine initiation by activating the expression of the Tril gene in cucumber. This work not only provides an important reference for understanding the molecular mechanisms of fruit spine development but also provides an important resource for fruit appearance quality breeding in cucumber.

An early HMGB1 rise 12 hours before creatinine predicts acute kidney injury and multiple organ failure in a smoke inhalation and burn swine model.

Acute kidney injury (AKI) and multiple organ failure (MOF) are leading causes of mortality in trauma injuries. Early diagnosis of AKI and MOF is vital to improve outcomes, but current diagnostic criteria rely on laboratory markers that are delayed or unreliable. In this study, we investigated whether damage associated molecular patterns such as high-mobility group box 1 (HMGB1), syndecan-1 (SDC-1) and C3a correlate with the development of trauma-induced AKI and MOF. Thirty-nine swine underwent smoke inhalation and severe burns, then received critical care for 72 hours or until death. AKI was defined by the KDIGO (Kidney Disease: Improving Global Outcomes) criteria, which labels AKI when a 1.5-fold increase in blood creatinine levels from baseline or a urine output < 0.5 mL/kg/h for 6 hours or more occurs. MOF was defined by the presence of both AKI and acute respiratory distress syndrome (PaO2/FiO2<300 for 4 hours). Eight of 39 pigs developed AKI and seven of those developed MOF. Pathological analysis revealed that polytrauma induces significantly higher kidney injury scores compared to sham controls. The average time from injury to KDIGO AKI was 24 hours (interquartile range: 22.50-32.25). Twelve hours after injury, HMGB1 levels were significantly increased in animals that went on to develop AKI compared to those that did not (73.07 ± 18.66 ng/mL vs. 31.64 ± 4.15 ng/mL, p<0.01), as well as in animals that developed MOF compared to those that did not (81.52±19.68 ng/mL vs. 31.19 ± 3.972 ng/mL, p<0.05). SDC-1 and C3a levels were not significantly different at any time point between groups. ROC analysis revealed that HMGB1 levels at 12 hours post-injury were predictive of both AKI and MOF development (AKI: AUROC=0.81, cut-off value=36.41 ng/mL; MOF: AUROC=0.89, cut-off value=36.41 ng/mL). Spearman's correlation revealed that HMGB1 levels at 12 hours correlated with multiple parameters of AKI, including blood urea nitrogen, blood creatinine, and blood myoglobin. Twelve-hour post-injury HMGB1 levels predict AKI and MOF in a smoke inhalation and burn swine model. Further research is needed to validate this result in other polytrauma models and in critical combat causalities.