The mechanism of HMGB1 secretion and release

High mobility group box 1 in the central nervous system: regeneration hidden beneath inflammation

High-mobility group box 1 was first discovered in the calf thymus as a DNA-binding nuclear protein and has been widely studied in diverse fields, including neurology and neuroscience. High-mobility group box 1 in the extracellular space functions as a pro-inflammatory damage-associated molecular pattern, which has been proven to play an important role in a wide variety of central nervous system disorders such as ischemic stroke, Alzheimer's disease, frontotemporal dementia, Parkinson's disease, multiple sclerosis, epilepsy, and traumatic brain injury. Several drugs that inhibit high-mobility group box 1 as a damage-associated molecular pattern, such as glycyrrhizin, ethyl pyruvate, and neutralizing anti-high-mobility group box 1 antibodies, are commonly used to target high-mobility group box 1 activity in central nervous system disorders. Although it is commonly known for its detrimental inflammatory effect, high-mobility group box 1 has also been shown to have beneficial pro-regenerative roles in central nervous system disorders. In this narrative review, we provide a brief summary of the history of high-mobility group box 1 research and its characterization as a damage-associated molecular pattern, its downstream receptors, and intracellular signaling pathways, how high-mobility group box 1 exerts the repair-favoring roles in general and in the central nervous system, and clues on how to differentiate the pro-regenerative from the pro-inflammatory role. Research targeting high-mobility group box 1 in the central nervous system may benefit from differentiating between the two functions rather than overall suppression of high-mobility group box 1.

Targeting pericyte retention in Diabetic Retinopathy: a review

Diabetic retinopathy is a common yet severe complication of diabetes mellitus and is the leading cause of blindness in middle-aged adults. After years of poorly managed hyperglycemia, complications begin as non-proliferative diabetic retinopathy but can then progress into the proliferative stage marked by neovascularization of the retina. Multiple pathologic mechanisms caused by chronic hyperglycemia damage the retinal vasculature leading to pericyte drop out and the progression of the disease. This review outlines the major pathways of pathogenesis in diabetic retinopathy, highlighting the protective role pericytes play in preserving the blood-retinal barrier. Given the loss of this cell line is a defining feature of the disease, ways in which to prevent pericyte dropout within retinal vasculature is discussed, targeting various pathogenesis pathways of diabetic retinopathy.

Targeting acid ceramidase enhances antitumor immune response in colorectal cancer

INTRODUCTION

Acid ceramidase (hereafter referred as ASAH1) is an enzyme in sphingolipid metabolism that converts pro-survival ceramide into sphingosine. ASAH1 has been shown to be overexpressed in certain cancers. However, the role of ASAH1 in colorectal cancer still remain elusive.

OBJECTIVE

The present study is aimed to understand how ASAH1 regulates colorectal cancer (CRC) progression and resistance to checkpoint inhibitor therapy.

METHODS

Both pharmacological and genetic silencing of ASAH1 was used in the study. In vitro experiments were done on human and mouse CRC cell lines. The in vivo studies were conducted in NOD-SCID and BALB/c mice models. The combination of ASAH1 inhibitor and checkpoint inhibitor was tested using a syngeneic tumor model of CRC. Transcriptomic and metabolomic analyses were done to understand the effect of ASAH1 silencing.

RESULTS

ASAH1 is overexpressed in human CRC cases, and silencing the expression resulted in the induction of immunological cell death (ICD) and mitochondrial stress. The ASAH1 inhibitor (LCL-521), either as monotherapy or in combination with an anti-PD-1 antibody, resulted in reduction of tumors and, through induction of type I and II interferon response, activation of M1 macrophages and T cells, leading to enhanced infiltration of cytotoxic T cells. Our findings supported that the combination of LCL-521 and ICIs, which enhances the antitumor responses, and ASAH1 can be a druggable target in CRC.

PPM1G promotes autophagy and progression of pancreatic cancer via upregulating HMGB1

Pancreatic cancer remains one of the most aggressive and lethal malignancies worldwide, with a dismal 5-year relative survival rates of only 12%. Therefore, it is urgent to discover the key molecular markers to improve the therapeutic outcomes in pancreatic cancer. Herein, we first demonstrated that PPM1G is upregulated in pancreatic cancer and that PPM1G depletion decreases pancreatic cancer cell growth in vitro and in vivo. High PPM1G expression was linked to short overall survival of pancreatic cancer patients, which was further validated in the TCGA database. Moreover, by detecting Beclin 1, LC3-II, and SQSTM1/p62 expressions and observing autolysosome under transmission electron microscope, we discovered that PPM1G is a novel positive regulator of macroautophagy/autophagy. Furthermore, by using immunoprecipitation-mass spectrometry (IP-MS) analysis and following systemic molecular biology experiment, we demonstrated PPM1G promotes the autophagy and proliferation of pancreatic cancer by directly upregulating HMGB1. Additionally, patients with both high PPM1G and high HMGB1 exhibited poorer prognosis in our cohort. This study preliminarily investigated the possibility of PPM1G as a potential therapeutic target and prognostic biomarker in pancreatic cancer patients.

Immune effects of α and β radionuclides in metastatic prostate cancer

External beam radiotherapy is used for radical treatment of organ-confined prostate cancer and to treat lesions in metastatic disease whereas molecular radiotherapy with labelled prostate-specific membrane antigen ligands and radium-223 (223Ra) is indicated for metastatic prostate cancer and has demonstrated substantial improvements in symptom control and overall survival compared with standard-of-care treatment. Prostate cancer is considered an immunologically cold tumour, so limited studies investigating the treatment-induced effects on the immune response have been completed. However, emerging data support the idea that radiotherapy induces an immune response in prostate cancer, but whether the response is an antitumour or pro-tumour response is dependent on the radiotherapy regime and is also cell-line dependent. In vitro data demonstrate that single-dose radiotherapy regimes induce a greater immune-suppressive profile than fractionated regimes; less is known about the immune response induced by molecular radiotherapy agents, but evidence suggests that these agents might induce an immune-suppressive systemic immune response, indicated by increased expression of inhibitory checkpoint molecules such as programmed cell death 1 ligand 1 and 2, and that these changes could be associated with clinical response. Different radiotherapy modalities can induce distinct immune profiles, which can either activate or suppress immune-mediated tumour killing and the current preclinical models used for prostate cancer research are not yet optimal for studying the complexity of the radiotherapy-induced immune response.

Targeted sonodynamic therapy induces tumor cell quasi-immunogenic ferroptosis and macrophage immunostimulatory autophagy in glioblastoma

In this study, we demonstrated the mechanism of a glioblastoma (GBM)-targeted sonodynamic therapy (SDT) strategy employing platelets loaded with a sonosensitizer based on functionalized boron nitride nanoparticles carrying chlorin e6 (BNPD-Ce6). In the in vitro study, we first found that the BNPD-Ce6-mediated sonodynamic action (SDA) induced remarkable viability loss, DNA damage, and cell death in the GBM cells (GBCs) but not macrophages. Surprisingly, the SDA-exposed GBCs displayed a ferroptotic phenotype while the SDA-exposed macrophages underwent immuno-stimulatory autophagy and potently potentiated the SDA's toxicity to the GBCs. The ferroptotic GBCs induced by the SDA were found to be quasi-immunogenic, characterized by the emission of some alarmins such as ATP, HSP90, and CRT, but absent HMGB1, a potent endogenous adjuvant. As such, the SDA-stressed GBCs were unable to stimulate the BMDMs. This defect, interestingly, could be rescued by platelets as a donor of HMGB1 which markedly enhanced the BNPD-Ce6's sonotoxicity to the GBCs. In the in vivo study, we first employed BNPD-Ce6-loaded platelets to achieve ultrasound-triggered, targeted delivery of BNPD-Ce6 in grafted intra-cranial GBMs and subsequent sonodynamic tumor damage. An SDT regimen designed based on these results slowed the growth of grafted intra-cranial GBMs and significantly increased the survival of the host animals. Pathological examination of the SDT-treated GBMs revealed tissue necrosis and destruction and validated the in vitro observations. Finally, the depletion of macrophages was found to abrogate the efficacy of the SDT in subcutaneous GBC grafts. In conclusion, the BNPD-Ce6@Plt-mediated SDT is a practicable and efficacious anti-GBM therapy. Its therapeutic mechanism critically involves a synergy of tumor cell ferroptosis, macrophage stimulation, and platelet activation induced by the SDA.

The gut microbiota metabolite trimethylamine-N-oxide in children with β-thalassemia: potential implication for iron-induced renal tubular dysfunction

BACKGROUND

Renal tubular dysfunction is common in transfusion-dependent β thalassemia (β-TM). Iron overload, chronic anemia, and hypoxia are precipitating factors for renal insult. However, gut microbiota engagement in the renal insult has not been explored. Our work aimed to assess the potential link between iron overload, gut leakage/dysbiosis, and kidney dysfunction in these children.

METHODS

We enrolled 40 children with β-TM and 40 healthy controls. Gut leakage/dysbiosis biomarkers (trimethylamine-N-oxide [TMAO] and fecal short-chain fatty acids [SCFAs]), oxidative stress and inflammatory biomarkers, TMAO-regulated proteins such as serum sirtuin 1 (S.SIRT1) and serum high mobility box group-1 (S.HMGB1), and tubular dysfunction biomarkers were assessed. Correlations and regression analysis were performed to assess the relation between different parameters.

RESULTS

Iron overload, redox imbalance, and generalized inflammation were evident in children with β-TM. Renal tubular dysfunction biomarkers and S.TMAO were significantly elevated in the patient group. Furthermore, fecal SCFAs were significantly lower with upregulation of the investigated genes in the patient group. The correlation studies affirmed the close relationship between circulating ferritin, TMAO, and renal dysfunction and strongly implicated SIRT1/HMGB1 axis in TMAO action.

CONCLUSIONS

Gut dysbiosis may have a role in the pathogenesis of renal injury in children with β-TM.

IMPACT

Renal tubular dysfunction is a prominent health issue in β thalassemia major (β-TM). Iron overload, chronic anemia, and hypoxia are known precipitating factors. However, gut microbiota engagement in renal insult in these patients has not yet been explored. We aimed to assess potential link between iron overload, gut leakage/dysbiosis, and kidney dysfunction in β-TM children and to highlight the SIRT1/HMGB1 axis, a signal motivated by the gut microbiota-dependent metabolite trimethylamine-N-oxide (TMAO), involvement in such insults. We found that gut leakage/dysbiosis may have a role in kidney dysfunction in β-TM children by exacerbating the iron-motivated oxidative stress, inflammation, ferroptosis, and modulating SIRT1/HMGB1 axis.

Serum HMGB-1 released by ferroptosis and necroptosis as a novel potential biomarker for systemic lupus erythematosus

High mobility group box proterin-1 (HMGB-1) is a multifunctional protein that can be released by various programmed cell deaths (PCDs), such as necroptosis and ferroptosis. PCDs play a critical role in the pathogenesis of systemic lupus erythematosus (SLE). However, the role of HMGB-1 in the process of SLE remains unclear. This study aims to demonstrate the potential diagnosing role of serum HMGB-1 in SLE that released by necroptosis and ferroptosis. We found that the serum levels of HMGB-1, receptor-interacting protein kinase 3 (RIPK3) /mixed lineage kinase domain-like protein (MLKL) related with necroptosis, and metabolites associated with ferroptosis were significantly upregulated in SLE patients compared to HC individuals. These serum levels were positively correlated with SLE disease activity. Additionally, the serum level of HMGB-1 showed a strong positive correlated with the levels of RIPK3/MLKL and ferroptosis metabolites. Moreover, the serum level of HMGB-1 was correlated with renal involvement and high-antinuclear antibodies (ANA) titer. After SLE serum and interferon γ (IFN-γ) treatment in vitro, the level of necroptosis and ferroptosis markers were activated and HMGB1 was released both in HEK293 and HK2 cells. Clinically, HMGB-1 was considered as a significant independent risk factor in SLE serum by binary logistic assay. Notably, HMGB-1 exhibited outstanding diagnostic ability for SLE by the area under the curve (AUC) in receiver operating characteristic (ROC) curve analysis. Taken together, our study indicates that the serum level of HMGB-1 is a promising biomarker for the diagnosis and monitoring of SLE.

Knocking down macrophages Caspase-6 through HMGB1 coordinates macrophage trophoblast crosstalk to suppress ferroptosis and alleviate preeclampsia

OBJECTIVE

Caspase-6 is an important regulatory factor in innate immunity, inflammasome activation, and host defense, but its role in preeclampsia (PE) is unknown. This study aims to investigate the mechanism of Caspase-6 in the interaction between PE rats and macrophage-trophoblast cells, in order to provide a new theoretical basis for the treatment of PE.

METHODS

Co-cultures of THP-1 cells and HTR8/SVneo cells were employed to investigate the HMGB1 signaling in macrophages (transfection with si-Caspase-6) and HTR8/SVneo cells. The PE rat model was constructed by using the reduced uterine perfusion pressure (RUPP) surgery to explore the therapeutic effects of bone marrow-derived macrophages (BMDM) transfected with si-Caspase-6 in PE rats. ELISA, Western blot, immunofluorescence, etc., were employed to characterize the expression of ferroptosis-related markers.

RESULTS

Caspase-6 expression was significantly increased in CD14+ macrophages in the placental tissue of PE rats. Overexpression of Caspase-6 in THP-1 cells induced ferroptosis of HTR8/SVneo cells, but this process was blocked by anti-HMGB1 neutralizing antibody. Knockdown of Caspase-6 in macrophages could alleviate ferroptosis of HTR8/SVneo cells and restore its basic characteristics. Knockdown of Caspase-6 in BMDM downregulated ferroptosis in placental tissue of PE rats through HMGB1, thereby improving the disease phenotype in rats.

CONCLUSION

Knocking down Caspase-6 in BMDM regulated the crosstalk between macrophages and HTR8/SVneo cells through HMGB1, inhibiting HTR8/SVneo cell ferroptosis, thereby improving adverse pregnancy outcomes of PE.

The role of macrophage-derived exosomes in noncancer liver diseases: From intercellular crosstalk to clinical potential

Chronic liver disease has a substantial global prevalence and mortality rate. Macrophages, pivotal cells in innate immunity, exhibit remarkable heterogeneity and plasticity and play a considerable role in maintaining organ homeostasis, modulating inflammatory responses, and influencing disease progression in the liver. Exosomes, which can serve as conduits for intercellular communication, biomarkers, and therapeutic targets for a spectrum of diseases, have recently garnered increasing attention recently. Given that the liver is the organ with the highest macrophage content, a thorough understanding of the influence of macrophage-derived exosomes (MDEs) on noncancer liver disease pathogenesis and their potential therapeutic applications is paramount. Interactions among MDEs, hepatocytes, hepatic stellate cells (HSCs), and other nonparenchymal cells constitute a complex network regulates liver immune homeostasis. In this review, we summarize the latest progress in the current understanding of MDE heterogeneity and cellular crosstalk in noncancer liver diseases, as well as their potential clinical applications. Additionally, challenges and future directions are underscored.

Ginsenoside Rk3 Treats Corneal Injury Through the HMGB1/TLR4/NF-κB Pathway

The cornea serves as a vital protective shield for the eye, safeguarding its intricate internal structures from external threats. Damage to the cornea compromises this protective function, triggering inflammation and potentially causing long-term harm. While ginsenoside Rk3 has demonstrated potential for repairing the corneal barrier and reducing inflammation, its effectiveness in treating corneal damage remains relatively unexplored. This comprehensive study uses both in vivo and in vitro models to investigate the therapeutic capabilities of ginsenoside Rk3. Using two models of corneal damage, a benzalkonium chloride-induced mouse model and a high osmolarity-induced human corneal epithelial cell model, we scrutinized the effects of ginsenoside Rk3 treatment. Our results showed that ginsenoside Rk3-treated mice manifested reduced corneal damage and inflammation compared with their untreated counterparts. Furthermore, mice treated with ginsenoside Rk3 exhibited an organized arrangement of corneal cells and diminished stromal layer thickness, indicating reparative properties of ginsenoside Rk3. Additionally, ginsenoside Rk3 increased the expression of tight junction proteins, suppressed inflammatory factors, and decreased HMGB1 protein expression, thereby modulating downstream signaling pathways. Collectively, our findings present compelling evidence that ginsenoside Rk3 is a promising therapeutic option for corneal injury. By repairing the corneal barrier, mitigating inflammation, and modulating specific protein levels, ginsenoside Rk3 opens new avenues for managing corneal damage.

The Clinical and Sonographic Features of Cervical Muscle Involvement in Patients with Frozen Shoulder: A Retrospective Study

Background/Objectives: Frozen shoulder is a common shoulder disorder that often places limitations on the range of motion of the shoulder. The disease may induce neck pain due to overuse of the neck muscle in an attempt to compensate for lack of shoulder movement. In clinical practice, swelling and inflammation of the scalene and levator scapulae may be detected via sonography in patients with frozen shoulder. The aim of this study was, therefore, to determine whether the involvement of the scalene complex or levator scapulae could compensate for the limited motion of the shoulder in patients with frozen shoulder. Methods: We retrospectively reviewed the medical records of 362 patients with unilateral frozen shoulder. These patients were divided into four groups depending on the involvement of the scalene complex or levator scapulae muscle. The range of motion of the shoulder-encompassing flexion, abduction, and external rotation-was measured with a goniometer. We also performed an ultrasound scan on each shoulder. The involvement of the scalene complex and levator scapulae muscle was also assessed via musculoskeletal ultrasound. Results: The range of motion of the shoulder in terms of flexion, abduction, external rotation, and total range of motion differed significantly between the four groups (p < 0.05). Patients in whom the scalene complex or levator scapulae muscle was involved demonstrated a significantly wider range of motion in different shoulder directions than patients without the involvement of those muscles (p < 0.05). Conclusions: A greater range of motion in the shoulder can be obtained through the activation of the scalene complex or levator scapulae muscle, which act to compensate for the lack of shoulder movement in patients with frozen shoulder. These two muscles showed thickening and hypoechoic changes upon sonography.

HMGB1, an evolving pleiotropic protein critical for cellular and tissue homeostasis: Role in aging and age-related diseases

Aging is a universal biological process characterized by a progressive, cumulative decline in homeostatic capabilities and physiological functions, which inevitably increases vulnerability to diseases. A number of molecular pathomechanisms and hallmarks of aging have been recognized, yet we miss a thorough understanding of their complex interconnectedness. This review explores the molecular and cellular mechanisms underlying human aging, with a focus on the multiple roles of high mobility group Box 1 protein (HMGB1), the archetypal damage-associated molecular pattern (DAMP) molecule. In the nucleus, this non-histone chromatin-associated protein functions as a DNA chaperone and regulator of gene transcription, influencing DNA structure and gene expression. Moreover, this versatile protein can translocate to the cytoplasm to orchestrate other processes, such as autophagy, or be unconventionally secreted into the extracellular environment, where it acts as a DAMP, combining inflammatory and regenerative properties. Notably, lower expression of HMGB1 within the cell and its heightened extracellular release have been associated with diverse age-associated traits, making it a suitable candidate as a universal biomarker of aging. In this review, we outline the evidence implicating HMGB1 in aging, also in light of an evolutionary perspective on its functional pleiotropy, and propose critical issues that need to be addressed to gauge the value of HMGB1 as a potential biomarker across age-related diseases and therapeutic target to promote healthy longevity.

Macrophages-derived high-mobility group box-1 protein induces endothelial progenitor cells pyroptosis

Endothelial dysfunction is an important factor in the progress of sepsis. Endothelial progenitor cells (EPCs) are the precursor cells of endothelial cells and play a crucial role in the prognosis and treatment of sepsis. EPCs in the peripheral blood of patients with sepsis undergo pyroptosis, but the mechanism remains much of unknown. Serum high-mobility group box-1 (HMGB1) is significantly elevated in patients with sepsis, but whether it is related to EPCs pyroptosis is unknown. We used a cell model of sepsis in vitro to isolate EPCs for better observation. By detecting the pyroptosis-related indicators of EPCs and the level of release and acetylation of HMGB1 in inflammatory macrophages, it was found that HMGB1 released by inflammatory macrophages combined with receptor for advanced glycation end products (RAGE) is a key pathway to induce pyroptosis of EPCs.

Melittin treatment suppressed malignant NSCLC progression through enhancing CTSB-mediated hyperautophagy

Melittin is preclinically investigated as anticancer agent in multiple tumor types. But its regulation role and regulatory mechanism regarding NSCLC is unknown. In our investigation, Proteomic test was employed to identify proteins that expressed abnormally in cancer cells and that with Melittin treatmented. The results showed CTSB was one of the Top proteins with different expression levels in the lysosomes of Melittin-treatmented cancer cells and showed an up-regulation trend. CTSB expression was increased in NSCLC cancer tissues compared to adjacent normal tissues, as demonstrated in lung cancer tissue chips experiment. However, Melittin treatment increased the CTSB level in lysosomes, which inhibited the malignant progression of NSCLC. We hypothesized that the relative homeostasis of CTSB in cancer cells was destroyed, and CTSB exerts its hydrolytic effect excessively, resulting in excessive autophagy of cancer cells, thus inhibiting the malignant progression of cancer cells. The direct combination of Melittin and CTSB was proposed by molecular docking technique, LiP-SMap was used to analyze the target genes and active components extracted from high-throughput sequencing proteomic data, and successfully verified that melittin was successfully demonstrated to directly target CTSB-binding. In vivo and in vitro studies have shown that Melittin treatment inhibits the malignant progression of A549 and HCC1833 cells and animal tumors, namely non-small cell lung cancer, by promoting CTSB-mediated hyperautophagy. CTSB-specific inhibitor CA-074 Me and autophagy inhibitor 3-MA treatment reversed the inhibit effect of Melittin to the malignant progression of NSCLC. Taken together, Melittin treatment inhibited malignant progression regarding NSCLC through enhancing CTSB-mediated hyperautophagy.

Targeting the Sirtuin-1/PPAR-Gamma Axis, RAGE/HMGB1/NF-κB Signaling, and the Mitochondrial Functions by Canagliflozin Augments the Protective Effects of Levodopa/Carbidopa in Rotenone-Induced Parkinson's Disease

Background and Objectives: Parkinson's disease (PD) is a pathological state characterized by a combined set of abnormal movements including slow motion, resting tremors, profound stiffness of skeletal muscles, or obvious abnormalities in posture and gait, together with significant behavioral changes. Until now, no single therapeutic modality was able to provide a complete cure for PD. This work was a trial to assess the immunomodulatory effects of canagliflozin with or without levodopa/carbidopa on rotenone-induced parkinsonism in Balb/c mice. Materials and Methods: In a mouse model of PD, the effect of canagliflozin with or without levodopa/carbidopa was assessed at the behavioral, biochemical, and histopathological levels. Results: The combination of levodopa/carbidopa and canagliflozin significantly mitigated the changes induced by rotenone administration regarding the behavioral tests, striatal dopamine, antioxidant status, Nrf2 content, SIRT-1/PPAR-gamma axis, RAGE/HMGB1/NF-κB signaling, and mitochondrial dysfunction; abrogated the neuroinflammatory responses, and alleviated the histomorphologic changes induced by rotenone administration relative to the groups that received either levodopa/carbidopa or canagliflozin alone. Conclusions: Canagliflozin may represent a new adjuvant therapeutic agent that may add value to the combatting effects of levodopa/carbidopa against the pathological effects of PD.

Long noncoding RNA AK144717 exacerbates pathological cardiac hypertrophy through modulating the cellular distribution of HMGB1 and subsequent DNA damage response

DNA damage induced by oxidative stress during cardiac hypertrophy activates the ataxia telangiectasia mutated (ATM)-mediated DNA damage response (DDR) signaling, in turn aggravating the pathological cardiomyocyte growth. This study aims to identify the functional associations of long noncoding RNA (lncRNAs) with cardiac hypertrophy and DDR. The altered ventricular lncRNAs in the mice between sham and transverse aortic constriction (TAC) group were identified by microarray analysis, and a novel lncRNA AK144717 was found to gradually upregulate during the development of pathological cardiac hypertrophy induced by TAC surgery or angiotensin II (Ang II) stimulation. Silencing AK144717 had a similar anti-hypertrophic effect to that of ATM inhibitor KU55933 and also suppressed the activated ATM-DDR signaling induced by hypertrophic stimuli. The involvement of AK144717 in DDR and cardiac hypertrophy was closely related to its interaction with HMGB1, as silencing HMGB1 abolished the effects of AK144717 knockdown. The binding of AK144717 to HMGB1 prevented the interaction between HMGB1 and SIRT1, contributing to the increased acetylation and then cytosolic translocation of HMGB1. Overall, our study highlights the role of AK144717 in the hypertrophic response by interacting with HMGB1 and regulating DDR, hinting that AK144717 is a promising therapeutic target for pathological cardiac growth.

The role of Tim-3 blockade in the tumor immune microenvironment beyond T cells

Numerous preclinical studies have demonstrated the inhibitory function of T cell immunoglobulin mucin domain-containing protein 3 (Tim-3) on T cells as an inhibitory receptor, leading to the clinical development of anti-Tim-3 blocking antibodies. However, recent studies have shown that Tim-3 is expressed not only on T cells but also on multiple cell types in the tumor microenvironment (TME), including dendritic cells (DCs), natural killer (NK) cells, macrophages, and tumor cells. Therefore, Tim-3 blockade in the immune microenvironment not only affect the function of T cells but also influence the functions of other cells. For example, Tim-3 blockade can enhance the ability of DCs to regulate innate and adaptive immunity. The role of Tim-3 blockade in NK cells function is controversial, as it can enhance the antitumor function of NK cells under certain conditions while having the opposite effect in other situations. Additionally, Tim-3 blockade can promote the reversal of macrophage polarization from the M2 phenotype to the M1 phenotype. Furthermore, Tim-3 blockade can inhibit tumor development by suppressing the proliferation and metastasis of tumor cells. In summary, increasing evidence has shown that Tim-3 in other cell types also plays a critical role in the efficacy of anti-Tim-3 therapy. Understanding the function of anti-Tim-3 therapy in non-T cells can help elucidate the diverse responses observed in clinical patients, leading to better development of relevant therapeutic strategies. This review aims to discuss the role of Tim-3 in the TME and emphasize the impact of Tim-3 blockade in the tumor immune microenvironment beyond T cells.

A Review of Biomarkers of Amyotrophic Lateral Sclerosis: A Pathophysiologic Approach

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive degeneration of upper and lower motor neurons. The heterogeneous nature of ALS at the clinical, genetic, and pathological levels makes it challenging to develop diagnostic and prognostic tools that fit all disease phenotypes. Limitations associated with the functional scales and the qualitative nature of mainstay electrophysiological testing prompt the investigation of more objective quantitative assessment. Biofluid biomarkers have the potential to fill that gap by providing evidence of a disease process potentially early in the disease, its progression, and its response to therapy. In contrast to other neurodegenerative diseases, no biomarker has yet been validated in clinical use for ALS. Several fluid biomarkers have been investigated in clinical studies in ALS. Biofluid biomarkers reflect the different pathophysiological processes, from protein aggregation to muscle denervation. This review takes a pathophysiologic approach to summarizing the findings of clinical studies utilizing quantitative biofluid biomarkers in ALS, discusses the utility and shortcomings of each biomarker, and highlights the superiority of neurofilaments as biomarkers of neurodegeneration over other candidate biomarkers.

Overcoming tyrosine kinase inhibitor resistance in lung cancer brain metastasis with CTLA4 blockade

Lung cancer brain metastasis (LCBM) poses a significant clinical challenge due to acquired resistance to tyrosine kinase inhibitor (TKI) treatment. To elucidate its underlying mechanisms, we employed single-cell RNA sequencing analysis on surgically obtained LCBM samples with diverse genetic backgrounds and TKI treatment histories. Our study uncovers that TKI treatment elevates the immune checkpoint CTLA4 expression in T cells, promoting an immune-suppressive microenvironment. This immunomodulation is initiated by tumor-derived HMGB1 in response to TKIs. In LCBM syngeneic murine models with TKI-sensitive or TKI-resistant EGFR mutations, combining CTLA4 blockade with TKIs demonstrates enhanced efficacy over TKI monotherapy or TKIs with PD1 blockade. These findings provide insights into the TKI resistance mechanisms and highlight the potential of CTLA4 blockade in effectively overcoming TKI resistance in LCBM.

A NIR-II Organic Dendrimer with Superb Photothermal Performance Based on Electron-Donor Iteration for Photothermal Immunotherapy

Organic photothermal materials have attracted extensive attention due to their designable molecular structure, tunable excited-state properties, and excellent biocompatibility, however, the development of near-infrared II (NIR-II) absorbing organic photothermal materials with high photothermal conversion efficiency (PTCE) and molar extinction coefficient (ɛ) remains challenging. Herein, a novel "electron-donor iteration" strategy is proposed to construct organic photothermal dendrimers (CR-DPA-T, CR-(DPA)2-T and CR-(DPA)3-T) with donor-π-acceptor-π-donor (D-π-A-π-D) features and diradical characteristics. Owing to the enhanced D-A effect and intramolecular motions, their absorption and photothermal capacity increase as the generation grows. Surprisingly, an excellent photothermal performance (ɛ1064 × PTCE1064) with a superb value of 2.85 × 104 in the NIR-II region is achieved for CR-(DPA)3-T nanoparticles (CR-(DPA)3-T NPs) compared to most reported counterparts. Besides, CR-(DPA)3-T NPs exhibit superior antitumor efficacy by the synergistic effect of photothermal therapy (PTT) and immunotherapy, efficiently inhibiting the growth of both primary and distant tumors. To the best knowledge, organic photothermal dendrimer is for the first time reported, and a universal donor engineering strategy is offered to develop NIR-II-absorbing organic photothermal materials for photothermal immunotherapy.

Aquaporin proteins: A promising frontier for therapeutic intervention in cerebral ischemic injury

Cerebral ischemic injury is characterized by reduced blood flow to the brain, remains a significant cause of morbidity and mortality worldwide. Despite improvements in therapeutic approaches, there is an urgent need to identify new targets to lessen the effects of ischemic stroke. Aquaporins, a family of water channel proteins, have recently come to light as promising candidates for therapeutic intervention in cerebral ischemic injury. There are 13 aquaporins identified, and AQP4 has been thoroughly involved with cerebral ischemia as it has been reported that modulation of AQP4 activity can offers a possible pathway for therapeutic intervention along with their role in pH, osmosis, ions, and the blood-brain barrier (BBB) as possible therapeutic targets for cerebral ischemia injury. The molecular pathways which can interacts with particular cellular pathways, participation in neuroinflammation, and possible interaction with additional proteins thought to be involved in the etiology of a stroke. Understanding these pathways offers crucial information on the diverse role of AQPs in cerebral ischemia, paving the door for the development of focused/targeted therapeutics.

Formation of multinucleated osteoclasts depends on an oxidized species of cell surface-associated La protein

The bone-resorbing activity of osteoclasts plays a critical role in the life-long remodeling of our bones that is perturbed in many bone loss diseases. Multinucleated osteoclasts are formed by the fusion of precursor cells, and larger cells - generated by an increased number of cell fusion events - have higher resorptive activity. We find that osteoclast fusion and bone resorption are promoted by reactive oxygen species (ROS) signaling and by an unconventional low molecular weight species of La protein, located at the osteoclast surface. Here, we develop the hypothesis that La's unique regulatory role in osteoclast multinucleation and function is controlled by an ROS switch in La trafficking. Using antibodies that recognize reduced or oxidized species of La, we find that differentiating osteoclasts enrich an oxidized species of La at the cell surface, which is distinct from the reduced La species conventionally localized within cell nuclei. ROS signaling triggers the shift from reduced to oxidized La species, its dephosphorylation and delivery to the surface of osteoclasts, where La promotes multinucleation and resorptive activity. Moreover, intracellular ROS signaling in differentiating osteoclasts oxidizes critical cysteine residues in the C-terminal half of La, producing this unconventional La species that promotes osteoclast fusion. Our findings suggest that redox signaling induces changes in the location and function of La and may represent a promising target for novel skeletal therapies.

Repair and regeneration: ferroptosis in the process of remodeling and fibrosis in impaired organs

As common clinical-pathological processes, wound healing and tissue remodelling following injury or stimulation are essential topics in medical research. Promoting the effective healing of prolonged wounds, improving tissue repair and regeneration, and preventing fibrosis are important and challenging issues in clinical practice. Ferroptosis, which is characterized by iron overload and lipid peroxidation, is a nontraditional form of regulated cell death. Emerging evidence indicates that dysregulated metabolic pathways and impaired iron homeostasis play important roles in various healing and regeneration processes via ferroptosis. Thus, we review the intrinsic mechanisms of tissue repair and remodeling via ferroptosis in different organs and systems under various conditions, including the inflammatory response in skin wounds, remodeling of joints and cartilage, and fibrosis in multiple organs. Additionally, we summarize the common underlying mechanisms, key molecules, and targeted drugs for ferroptosis in repair and regeneration. Finally, we discuss the potential of therapeutic agents, small molecules, and novel materials emerging for targeting ferroptosis to promote wound healing and tissue repair and attenuate fibrosis.

Synovial microenvironment in temporomandibular joint osteoarthritis: crosstalk with chondrocytes and potential therapeutic targets

Temporomandibular joint osteoarthritis (TMJOA) is considered to be a low-grade inflammatory disease involving multiple joint tissues. The crosstalk between synovium and cartilage plays an important role in TMJOA. Synovial cells are a group of heterogeneous cells and synovial microenvironment is mainly composed of synovial fibroblasts (SF) and synovial macrophages. In TMJOA, SF and synovial macrophages release a large number of inflammatory cytokines and extracellular vesicles and promote cartilage destruction. Cartilage wear particles stimulate SF proliferation and macrophages activation and exacerbate synovitis. In TMJOA, chondrocytes and synovial cells exhibit increased glycolytic activity and lactate secretion, leading to impaired chondrocyte matrix synthesis. Additionally, the synovium contains mesenchymal stem cells, which are the seed cells for cartilage repair in TMJOA. Co-culture of chondrocytes and synovial mesenchymal stem cells enhances the chondrogenic differentiation of stem cells. This review discusses the pathological changes of synovium in TMJOA, the means of crosstalk between synovium and cartilage, and their influence on each other. Based on the crosstalk between synovium and cartilage in TMJOA, we illustrate the treatment strategies for improving synovial microenvironment, including reducing cell adhesion, utilizing extracellular vesicles to deliver biomolecules, regulating cellular metabolism and targeting inflammatory cytokines.

Anti-inflammatory compounds from the rhizome of Acorus calamus var. angustatus Besser and their mechanism

Seven compounds, named β-sitosterol (1), daucosterol (2), (+)-pinoresinol-β-D-glucoside (3), (-)-syringaresinol 4-O-β-D-apiofuranosyl-(1→2)- β-D-glucopyranoside (4), 4-hydroxybenzoic acid (5), 2-(3', 4'-dihydroxyphenyl)-1, 3-pepper ring-5-aldehyde (6) and spinosin (7) were isolated from the rhizome of Acorus calamus var. angustatus Besser. 3, 4, 6 and 7 were isolated from this medicinal plant for the first time. Structures were elucidated by physicochemical properties and extensive spectroscopic analysis, as well as by comparison with literature data. The anti-inflammatory activity and related mechanisms of the seven compounds showed that compounds 1-7 all increased the levels of GSH-PX and SOD and decreased the levels of MDA, TNF-α, IL-1β and IL-6. Compound 4 showed the best effect of anti-inflammatory and Beclin-1 inhibition. These results suggest that compound 4 has stronger anti-inflammatory effect and provide preliminary evidence that the mechanism of action of compound 4 in attenuating LPS-induced inflammatory damage may be related to the inhibition of Beclin-1-dependent autophagy.

RAGE participates in the intracellular transport of Campylobacter jejuni cytolethal distending toxin

BACKGROUND

Cytolethal distending toxin (CDT) belongs to the genotoxin family and is closely related to Campylobacter jejuni-associated gastroenteritis. We recently reported that CDT triggers the danger-associated molecular pattern (DAMP) signaling to exert deleterious effects on host cells. However, how CDT traffics in cells and the mechanism of CDT intoxication remain to be elucidated.

METHODS

Recombinant CDT subunits (CdtA, CdtB, and CdtC) were purified, and their activity was characterized in gastrointestinal cells. Molecular approaches and image tracking were employed to analyze the delivery of CDT in host cells.

RESULTS

In this study, we found that CDT interacts with the receptor of advanced glycation end products (RAGE) and high mobility group box 1 (HMGB1) to enter the cells. Our results further showed that CdtB transport in cells through the dynamin-dependent endocytic pathway and lysosome is involved in this process. Conversely, blockage of RAGE signaling resulted in a reduction in CDT-arrested cell cycles, indicating that RAGE is involved in CDT intracellular transport and its subsequent pathogenesis.

CONCLUSION

Our results demonstrate that RAGE is important for CDT trafficking in the cells. These findings expand our understanding of important issues related to host cell intoxication by C. jejuni CDT.

High Mobility Group Box Protein (HMGB1): A Potential Therapeutic Target for Diabetic Encephalopathy

HMGB (high mobility group B) is one of the ubiquitous non-histone nuclear protein superfamilies that make up the HMG (high mobility group) protein group. HMGB1 is involved in a variety of physiological and pathological processes in the human body, including a structural role in the cell nucleus as well as replication, repair, DNA transcription, and assembly of nuclear proteins. It functions as a signaling regulator in the cytoplasm and a pro-inflammatory cytokine in the extracellular environment. Among several studies, HMGB1 protein is also emerging as a crucial factor involved in the development and progression of diabetic encephalopathy (DE) along with other factors such as hyperglycaemia-induced oxidative and nitrosative stress. Diabetes' chronic side effect is DE, which manifests as cognitive and psychoneurological dysfunction. The HMGB1 is released outside to the extracellular medium in diabetes condition through active or passive routes, where it functions as a damage-associated molecular pattern (DAMP) molecule to activate several signaling pathways by interacting with receptors for advanced glycosylation end-products (RAGE)/toll like receptors (TLR). HMGB1 reportedly activates inflammatory pathways, disrupts the blood-brain barrier, causes glutamate toxicity and oxidative stress, and promotes neuroinflammation, contributing to the development of cognitive impairment and neuronal damage which is suggestive of the involvement of HMGB1 in the enhancement of the diabetes-induced encephalopathic condition. Additionally, HMGB1 is reported to induce insulin resistance, further exacerbating the metabolic dysfunction associated with diabetes mellitus (DM). Thus, the present review explores the possible pathways associated with DM-induced hyperactivation of HMGB1 ultimately leading to DE.

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.

Targeting non-classical autophagy-dependent ferroptosis and the subsequent HMGB1/TfR1 feedback loop accounts for alleviating solar dermatitis by senkyunolide I

Given the substantial risks associated with ultraviolet B (UVB) radiation-induced solar dermatitis, enhancing current strategies to combat UVB regarding skin diseases is imperative. The cross-talk between ferroptosis and inflammation has been proven to be an essential factor in UVB-induced solar dermatitis, whereas detailed process of how their interaction contributes to this remains unclear. Therefore, further investigation of ferroptosis-mediated processes and identification of corresponding inhibitory approaches hold promise for repairing skin damage. Senkyunolide I (Sen I), a bioactive component mainly extracted from the traditional Chinese medicinal plants, Ligusticum chuanxiong Hort. and Angelica sinensis (Oliv.) Diels, has demonstrated efficacy in combating oxidative stress and inflammation. In this study, we utilized UVB-irradiated HaCaT cells as an in vitro model and C57BL/6J mice as an in vivo model of solar dermatitis. Our findings revealed the pivotal roles of autophagy and ferroptosis in inducing skin inflammation, particularly emphasizing the activation of ferroptosis through macroautophagy. Surprisingly, this mechanism operated independently of ferritinophagy, a classical autophagy-driven ferroptosis pathway. Instead, our results highlighted Transferrin Receptor 1 (TfR1), tightly controlled by autophagy, as a crucial mediator of ferroptosis execution and amplifier of subsequent lethal signals. Furthermore, extracellular High Mobility Group Box 1 protein (HMGB1), released following UVB-induced ferroptotic cells from activated autophagic flux, initiated a feedback loop with TfR1, propagating ferroptosis to neighboring cells and exacerbating damage. Remarkably, Sen I administration showed a significant protective effect against UVB damage in both in vitro and in vivo models by interrupting this cascade. Consequently, we have illuminated a novel therapeutic pathway post-UVB exposure and identified Sen I as a potent natural molecule that safeguarded against UVB-induced solar dermatitis by suppressing the autophagy-ferroptosis-HMGB1-TfR1 axis, highlighting a new frontier in photoprotection.

Lipocalin-2 aggravates blood-brain barrier dysfunction after intravenous thrombolysis by promoting endothelial cell ferroptosis via regulating the HMGB1/Nrf2/HO-1 pathway

BACKGROUND

Disruption of the blood-brain barrier (BBB) is a major contributor to hemorrhagic transformation (HT) in patients with acute ischemic stroke (AIS) following intravenous thrombolysis (IVT). However, the clinical therapies aimed at BBB protection after IVT remain limited.

METHODS

One hundred patients with AIS who underwent IVT were enrolled (42 with HT and 58 without HT 24 h after IVT). Based on the cytokine chip, the serum levels of several AIS-related proteins, including LCN2, ferritin, matrix metalloproteinase-3, vascular endothelial-derived growth factor, and X-linked inhibitor of apoptosis, were detected upon admission, and their associations with HT were analyzed. After finding that LCN2 was related to HT in patients with IVT, we clarified whether the modulation of LCN2 influenced BBB dysfunction and HT after thrombolysis and investigated the potential mechanism.

RESULTS

In patients with AIS following IVT, logistic regression analysis showed that baseline serum LCN2 (p = 0.023) and ferritin (p = 0.046) levels were independently associated with HT. A positive correlation between serum LCN2 and ferritin levels was identified in patients with HT. In experimental studies, recombinant LCN2 (rLCN2) significantly aggravated BBB dysfunction and HT in the thromboembolic stroke rats after thrombolysis, whereas LCN2 inhibition by ZINC006440089 exerted opposite effects. Further mechanistic studies showed that, LCN2 promoted endothelial cell ferroptosis, accompanied by the induction of high mobility group box 1 (HMGB1) and the inhibition of nuclear translocation of nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) proteins. Ferroptosis inhibitor ferrostatin-1 (fer-1) significantly restricted the LCN2-mediated BBB disruption. Transfection of LCN2 and HMGB1 siRNA inhibited the endothelial cell ferroptosis, and this effects was reversed by Nrf2 siRNA.

CONCLUSION

LCN2 aggravated BBB disruption after thrombolysis by promoting endothelial cell ferroptosis via regulating the HMGB1/Nrf2/HO-1 pathway, this may provide a promising therapeutic target for the prevention of HT after IVT.

Thiols-rich peptide from water buffalo horn keratin alleviates oxidative stress and inflammation through co-regulating Nrf2/Hmox-1 and NF-κB signaling pathway

Water buffalo horn (WBH), a traditional Chinese medicine, is known for its antipyretic, anti-inflammatory and antioxidant properties. This study aims to investigate the therapeutic potential of WBH keratin (WBHK) and its derived thiol-rich peptide fractions (SHPF) for oxidative stress and inflammation. WBHK and SHPF were prepared and tested using various models including LPS-induced fever in rabbits, H2O2-induced oxidative damage in bEnd.3 cells, TNF-α-induced inflammation in bEnd.3 cells and LPS-induced inflammation in RAW 264.7 cells. Expression of key markers, such as Nrf2, Hmox-1 and NF-κB, were analyzed using qRT-PCR, ELISA and Western blotting. Label-free quantitative proteomic analysis was used to identify key differential proteins associated with the efficacy of SHPF. Our results demonstrated that treatment with WBHK significantly reduced body temperature after 0.5 h of administration in the fever rabbit model. SHPF could alleviate cellular inflammatory injury and oxidative damage by activating the key transcription factor Nrf2 and increasing the expression level of Hmox-1. SHPF could inhibit the NF-κB pathway by reducing IκB phosphorylation. It was also found that SHPF could reduce pro-inflammatory cytokine (IL-6, COX-2 and PGE2) and inhibit the expression of VCAM-1, ICAM-1, IL-6 and MCP-1. Proteomics analysis showed that SHPF could inhibit HMGB1 expression and release. The results indicated that SHPF could significantly reduce inflammation and oxidative stress by regulating the Nrf2/Hmox-1 and NF-κB pathways. These findings suggest the potential therapeutic applications of WBH components in the treatment of oxidative stress and inflammation-related diseases.

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-1β 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.

SARS-CoV-2 ORF3a induces COVID-19-associated kidney injury through HMGB1-mediated cytokine production

The primary challenge posed by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is COVID-19-related mortality, often exacerbated by additional medical complications, such as COVID-19-associated kidney injuries (CAKIs). Up to half of COVID-19 patients experience kidney complications, with those facing acute respiratory failure and kidney injury having the worst overall prognosis. Despite the significant impact of CAKI on COVID-19-related mortality and its enduring effects in long COVID, the underlying causes and molecular mechanisms of CAKI remain elusive. In this study, we identified a functional relationship between the expression of the SARS-CoV-2 ORF3a protein and inflammation-driven apoptotic death of renal tubular epithelial cells in patients with CAKI. We demonstrate in vitro that ORF3a independently induces renal cell-specific apoptotic cell death, as evidenced by the elevation of kidney injury molecule-1 (KIM-1) and the activation of NF-kB-mediated proinflammatory cytokine (TNFα and IL-6) production. By examining kidney tissues of SARS-CoV-2-infected K18-ACE2 transgenic mice, we observed a similar correlation between ORF3a-induced cytopathic changes and kidney injury. This correlation was further validated through reconstitution of the ORF3a effects via direct adenoviral injection into mouse kidneys. Through medicinal analysis, we identified a natural compound, glycyrrhizin (GL4419), which not only blocks viral replication in renal cells, but also mitigates ORF3a-induced renal cell death by inhibiting activation of a high mobility group box 1 (HMGB1) protein, leading to a reduction of KIM-1. Moreover, ORF3a interacts with HMGB1. Overproduction or downregulation of hmgb1 expression results in correlative changes in renal cellular KIM-1 response and respective cytokine production, implicating a crucial role of HMGB1 in ORF3a-inflicted kidney injuries. Our data suggest a direct functional link between ORF3a and kidney injury, highlighting ORF3a as a unique therapeutic target contributing to CAKI.

IMPORTANCE

The major challenge of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during the pandemic is COVID-19-related mortality, which has tragically claimed millions of lives. COVID-19-associated morbidity and mortality are often exacerbated by pre-existing medical conditions, such as chronic kidney diseases (CKDs), or the development of acute kidney injury (AKI) due to COVID-19, collectively known as COVID-19-associated kidney injuries (CAKIs). Patients who experience acute respiratory failure with CAKI have the poorest clinical outcomes, including increased mortality. Despite these alarming clinical findings, there is a critical gap in our understanding of the underlying causes of CAKI. Our study establishes a direct correlation between the expression of the SARS-CoV-2 viral ORF3a protein and kidney injury induced by ORF3a linking to CAKI. This functional relationship was initially observed in our clinical studies of COVID-19 patients with AKI and was further validated through animal and in vitro cellular studies, either by expressing ORF3a alone or in the context of viral infection. By elucidating this functional relationship and its underlying mechanistic pathways, our research deepens the understanding of COVID-19-associated kidney diseases and presents potential therapeutic avenues to address the healthcare challenges faced by individuals with underlying conditions.

Elevated Serum HMGB1 Levels and Their Association with Recurrence of Acute Ischaemic Stroke

Purpose

The study aimed to investigate the correlation between baseline serum levels of high mobility group box 1 (HMGB1) and the recurrence of acute ischemic stroke (AIS).

Patients and Methods

A total of 544 AIS patients were enrolled and followed up monthly. Serum HMGB1 levels were measured using enzyme-linked immunosorbent assay (ELISA). The primary endpoint was the first recurrence of AIS.

Results

During a median follow-up period of 43 months, 62 of the 544 AIS patients experienced a recurrence. Both HMGB1 levels and national institute of health stroke scale (NIHSS) scores were significantly higher in the recurrence group compared to the no-recurrence group (p<0.05). According to the receiver operating characteristic curve analysis, the combination (0.855, 95% CI: 0.800-0.911) of HMGB1 (0.745, 95% CI: 0.663-0.826) and NIHSS (0.822, 95% CI: 0.758-0.886) had a higher value for predicting AIS recurrence than either of them (p<0.05). Kaplan-Meier analyses demonstrated that the cumulative survival without AIS recurrence was significantly lower in patients in the high HMGB1 level group than in the low HMGB1 level group (p<0.05). The multifactorial Cox analyses indicated that elevated baseline serum HMGB1 levels (HR: 7.489, 95% CI:4.383-12.795) were a highly effective predictor of recurrence in AIS.

Conclusion

Elevated baseline serum HMGB1 levels were found to be a highly effective predictor of recurrence in AIS.

Plasmodium berghei HMGB1 controls the host immune responses and splenic clearance by regulating the expression of pir genes

High mobility group box (HMGB) proteins belong to the high mobility group (HMG) superfamily of non-histone nuclear proteins that are involved in chromatin remodeling, regulation of gene expression, and DNA repair. When extracellular, HMGBs serve as alarmins inducing inflammation, and this is attributed to the proinflammatory activity of box B. Here, we show that Plasmodium HMGB1 has key amino acid changes in box B resulting in the loss of TNF-α stimulatory activity. Site-directed mutagenesis of the critical amino acids in box B with respect to mouse HMGB1 renders recombinant Plasmodium berghei (Pb) HMGB1 capable of inducing TNF-α release. Targeted deletion of PbHMGB1 and a detailed in vivo phenotyping show that PbHMGB1 knockout (KO) parasites can undergo asexual stage development. Interestingly, Balb/c mice-infected with PbHMGB1KO parasites display a protective phenotype with subsequent clearance of blood parasitemia and develop long-lasting protective immunity against the challenges performed with Pb wildtype parasites. The characterization of splenic responses shows prominent germinal centers leading to effective humoral responses and enhanced T follicular helper cells. There is also complete protection from experimental cerebral malaria in CBA/CaJ mice susceptible to cerebral pathogenesis with subsequent parasite clearance. Transcriptomic studies suggest the involvement of PbHMGB1 in pir expression. Our findings highlight the gene regulatory function of parasite HMGB1 and its in vivo significance in modulating the host immune responses. Further, clearance of asexual stages in PbHMGB1KO-infected mice underscores the important role of parasite HMGB1 in host immune evasion. These findings have implications in developing attenuated blood-stage vaccines for malaria.

Comprehensive review of drug-mediated ICD inhibition of breast cancer: mechanism, status, and prospects

The escalating incidence of breast cancer (BC) in women underscores its grave health threat. Current molecular insights into BC's post-adjuvant therapy cure remain elusive, necessitating active treatment explorations. Immunotherapy, notably chemotherapy-induced immunogenic cell death (ICD), has emerged as a promising BC therapy. ICD harnesses chemotherapeutics to activate anti-tumor immunity via DAMPs, fostering long-term T-cell memory and primary BC cure. Besides chemotherapy drugs, Nanodrugs, traditional Chinese medicine (TCM) and ICIs also induce ICD, boosting immune response. ICIs, like PD-1/PD-L1 inhibitors, revolutionize cancer treatment but face limited success in cold tumors. Thus, ICD induction combined with ICIs is studied extensively for BC immunotherapy. This article reviews the mechanism of ICD related drugs in BC and provides reference for the research and development of BC treatment, in order to explore more effective clinical treatment of BC, we hope to explore more ICD inducers and make ICIs more effective vaccines.

Alarmin-loaded extracellular lipid droplets induce airway neutrophil infiltration during type 2 inflammation

Group 2 innate lymphoid cells (ILC2s) play a crucial role in allergic diseases by coordinating a complex network of various effector cell lineages involved in type 2 inflammation. However, their function in regulating airway neutrophil infiltration, a deleterious symptom of severe asthma, remains unknown. Here, we observed ILC2-dependent neutrophil accumulation in the bronchoalveolar lavage fluid (BALF) of allergic mouse models. Chromatography followed by proteomics analysis identified the alarmin high mobility group box-1 (HMGB1) in the supernatant of lung ILC2s initiated neutrophil chemotaxis. Genetic perturbation of Hmgb1 in ILC2s reduced BALF neutrophil numbers and alleviated airway inflammation. HMGB1 was loaded onto the membrane of lipid droplets (LDs) released from activated lung ILC2s. Genetic inhibition of LD accumulation in ILC2s significantly decreased extracellular HMGB1 abundance and BALF neutrophil infiltration. These findings unveil a previously uncharacterized extracellular LD-mediated immune signaling delivery pathway by which ILC2s regulate airway neutrophil infiltration during allergic inflammation.

Oleuropein Relieves Pancreatic Ischemia Reperfusion Injury in Rats by Suppressing Inflammation and Oxidative Stress through HMGB1/NF-κB Pathway

Oleuropein (OLP) is a naturally occurring phenolic compound in olive plant with antioxidant and anti-inflammatory potential and can possibly be used in treating pancreatic injuries. This investigation aimed to follow the molecular mechanism behind the potential therapeutic effect of OLP against pancreatic injury persuaded by ischemia-reperfusion (I/R). Pancreatic I/R injury was induced by splenic artery occlusion for 60 min followed by reperfusion. Oral administration of OLP (10 and 20 mg/kg) for 2 days significantly alleviated I/R-persuaded oxidative damage and inflammatory responses in pancreatic tissue as indicated by the decreased malondialdehyde (MDA) content and increased glutathione peroxidase (GPx) activity, accompanied by the suppression of myeloperoxidase (MPO) activity and reduced levels of interleukin-1beta (IL-1β), nuclear factor kappa B (NF-κB), and tumor necrosis factor alpha (TNF-α) in pancreatic tissues. Furthermore, OLP treatment markedly restored the serum levels of amylase, trypsinogen-activated peptide (TAP), and lipase, with concurrent improvement in pancreatic histopathological alterations. Moreover, treatment with OLP regulated the pancreatic expression of inducible nitric oxide synthase (iNOS) and high-mobility group box 1 (HMGB1) relative to rats of the pancreatic IR group. Thus, OLP treatment significantly alleviates the I/R-induced pancreatic injury by inhibiting oxidative stress and inflammation in rats through downregulation of HMGB1 and its downstream NF-κB signaling pathway.

Lentivirus-mediated RNA interference targeting HMGB1 modulates AQP1 to reduce pain induced by chronic compression of the dorsal root ganglia

Backgrounds

Neuropathic pain (NP) is a kind of chronic pain that has attracted much attention in clinical practice, characterized by high morbidity, complex mechanisms, and difficulties in clinical treatment, with which the activation of High mobility group box 1 (HMGB1) is closely related. The aim of this study was to investigate the effects of lentivirus-mediated RNA interference gene therapy targeting HMGB1 on neuropathic pain in rats with chronic dorsal root ganglion compression (CCD) and its specific mechanisms, so as to explore new pharmacological targets.

Methods

Adult male Wistar rats were surgically subjected to chronic compression of the dorsal root ganglia (CCD). Behavioral tests were performed by calculating the paw withdrawal mechanical threshold (PWMT) and the thermal paw withdrawal latency (TPWL). Co-immunoprecipitation (CO-IP) was used to clarify protein interactions. Gene silencing was induced by injecting lentivirus expressing HMGB1 short hairpin RNA (shRNA) into rats. An LPS-inflammation-stimulated rat astrocyte model was established to validate the animal experiment results further. Western blot analysis and real-time quantitative PCR were used to detect pathway protein expression.

Results

After first establishing the rat CCD model, both PWMT and PTWL were significantly reduced in rats, indicating that the model construction was successful. After lentiviral silencing of HMGB1 expression, NP was significantly alleviated in CCD rats. CO-IP experiments showed a link between HMGB1 and AQP1; After silencing HMGB1 expression, the expression of AQP1 was significantly reduced, and HMGB1 was able to modulate the effect of AQP1 on NP. Further use of an inhibitor of the HMGB1 receptor showed that after inhibition of RAGE, AQP1 was significantly reduced; HMGB1 may regulate AQP1 through its receptor RAGE to affect NP. Silencing of HMGB1 resulted in a significant decrease in NF-κB, and HMGB1 affects the inflammatory pathways it mediates. After silencing AQP1, NF-κB also decreased significantly, indicating that AQP1 is an upstream regulator of NF-κB.

Conclusion

Lentivirus-mediated RNA interference (RNAi) silencing targeting HMGB1 may play a key role in the development of neuropathic pain in rats by regulating AQP1 expression via RAGE and ultimately activating NF-κB.

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.

Thermosensitive hydrogel as a sustained release carrier for mesenchymal stem cell-derived extracellular vesicles in the treatment of intrauterine adhesion

Intrauterine adhesion (IUA), a prevalent etiology of female infertility, is attributed to endometrial damage. However, conventional therapeutic interventions for IUA are plagued by high recurrence rates. Human umbilical cord mesenchymal stem cell-derived extracellular vesicles (hUCMSC-EVs) demonstrate the promising therapeutic effects on IUA, but the current efficacy of extracellular vesicles (EVs) is hindered by lower retention and bioavailability. In this study, a thermosensitive hydrogel was utilized as a prolonged release carrier to improve the retention and bioavailability of hUCMSC-EVs in IUA treatment. The hydrogel-EVs complex effectively prolonged EVs retention in human endometrial stromal cells and an IUA mouse model. The complex exhibited superior protection against cellular injury, significantly alleviated endometrial damage, inhibited fibrosis, suppressed inflammation, and improved fertility compared to EVs alone. The results indicated that thermosensitive hydrogel enhanced the therapeutic capacity of EVs for IUA by prolonging their retention in the uterine environment. The hydrogel-EVs complex provides a novel strategy for the sustained release of hUCMSC-EVs in the treatment of IUA.

A review of the potential adverse health impacts of atrazine in humans

Atrazine is a widely used chlorinated triazine herbicide in agricultural settings, which has raised concerns over its potential adverse effects on human health. The extensive application of atrazine has resulted in its pervasive presence in the environment, contaminating soil, groundwater, and surface water. While earlier research suggested that atrazine is unlikely to pose a health concern, recent evidence has indicated the necessity to reassess this point of view. This review aims to assess the recent evidence on atrazine's adverse effects on human health, focusing on (i) Cancer, (ii) Metabolic Diseases, (iii) Reproductive System, (iv) Neural System, and (v) Epigenetic Effects. Strategies to mitigate atrazine contamination and limitations of previous studies are also discussed. We strongly believe that further investigation is necessary to determine the potential detrimental consequences of atrazine in humans, particularly in developing countries, where herbicides are widely used without stringent safety regulations. Therefore, the current review will be beneficial for guiding future research and regulatory measures concerning the use of atrazine.

Transformable self-delivered supramolecular nanomaterials combined with anti-PD-1 antibodies alleviate tumor immunosuppression to treat breast cancer with bone metastasis

Breast cancer is the most common malignant tumor that threatens women's life and health, and metastasis often occurs in the advanced stage of breast cancer, leading to pathological bone destruction and seriously reducing patient quality of life. In this study, we coupled chlorin e6 (Ce6) with mono-(6-amino-6-deoxy)-beta-cyclodextrin (β-CD) to form Ce6-CD, and combined ferrocene with the FFVLG3C peptide and PEG chains to form the triblock molecule Fc-pep-PEG. In addition, the IDO-1 inhibitor NLG919 was loaded with Ce6-CD and Fc-pep-PEG to construct the supramolecular nanoparticle NLG919@Ce6-CD/Fc-pep-PEG (NLG919@CF). After laser irradiation, Ce6 produced robust reactive oxidative species to induce tumor cell apoptosis. Simultaneously, ferrocene became charged, and Fc-pep-PEG dissociated from the spherical nanoparticles, enabling their transformation into nanofibers, which increased both the retention effect and the induction of ferroptosis. The released NLG919 reduced the number of regulatory T cells (Tregs) and restored the function of cytotoxic T lymphocytes (CTLs) by inhibiting the activity of IDO-1. Moreover, combined administration with an anti-PD-1 antibody further relieved immune suppression in the tumor microenvironment. This article presents a new strategy for the clinical treatment of breast cancer with bone metastasis and osteolysis.

NLRP3 targets HMGB1 to exacerbate the pyroptosis of canine corneal epithelial cells infected with Staphylococcus pseudintermedius

PURPOSE

This study focused on the mechanisms of pyroptosis and oxidative damage exacerbation by NOD-like receptor thermal protein domain associated protein 3 (NLRP3) during the infection of canine corneal epithelial cells (CCECs) with Staphylococcus pseudintermedius.

METHODS

The CCECs treated with dimethyl fumarate (DMF), recombinant high mobility group protein 1 (HMGB1), or N-acetylcysteine (NAC). The gasdermin (GSDM) family and HMGB1 mRNA expression levels were detected using quantitative reverse transcription polymerase chain reaction. Lactate dehydrogenase activity, bacterial counts, the pyroptosis rate, reactive oxygen species (ROS) content, and antioxidant enzyme activity were used to reflect pyroptosis and oxidation level.

RESULTS

Regulation of NLRP3 significantly affected the pyroptosis rate and GSDMD-N expression levels during S. pseudintermedius infection. Inhibition of GSDMD-N protein activation by DMF reversed the exacerbation of pyroptosis induced by NLRP3 overexpression and reduced the levels of cleaved interleukin-1β (IL-1β), cleaved cysteinyl aspartate-specific protease-1, and NLRP3. In addition, NLRP3 was found to target the HMGB1 promoter and regulate its protein expression, to increase ROS accumulation and GSDMD-N expression levels, and activate the NLRP3-HMGB1-ROS-GSDMD signaling axis to aggravate pyroptosis during infection.

CONCLUSIONS

NLRP3 aggravates pyroptosis and oxidative damage associated with the activation of NLRP3-GSDMD and NLRP3-HMGB1-ROS-GSDMD signaling pathways during the infection of CCECs with S. pseudintermedius.

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 Protective Role of Interleukin-37 in Cardiovascular Diseases through Ferroptosis Modulation

The role of ferroptosis and iron metabolism dysregulation in the pathophysiology of cardiovascular diseases is increasingly recognized. Conditions such as hypertension, cardiomyopathy, atherosclerosis, myocardial ischemia/reperfusion injury, heart failure, and cardiovascular complications associated with COVID-19 have been linked to these processes. Inflammation is central to these conditions, prompting exploration into the inflammatory and immunoregulatory molecular pathways that mediate ferroptosis and its contribution to cardiovascular disease progression. Notably, emerging evidence highlights interleukin-37 as a protective cytokine with the ability to activate the nuclear factor erythroid 2-related factor 2 pathway, inhibit macrophage ferroptosis, and attenuate atherosclerosis progression in murine models. However, a comprehensive review focusing on interleukin-37 and its protective role against ferroptosis in CVD is currently lacking. This review aims to fill this gap by summarizing existing knowledge on interleukin-37, including its regulatory functions and impact on ferroptosis in conditions such as atherosclerosis and myocardial infarction. We also explore experimental strategies and propose that targeting interleukin-37 to modulate ferroptosis presents a promising therapeutic approach for the prevention and treatment of cardiovascular diseases.

Hepatoprotective effect of prenatal celecoxib in weaning preeclamptic rats: Role of HMGB1/MAPKs signaling

Preeclampsia (PE) is often associated with multiple organ damage that remains noticeable postnatally. Here, we tested the hypotheses that antenatal therapy with nonsteroidal antiinflammatory drugs (NSAIDs) refashions liver damage induced by PE in weaning rats and that the high mobility group box 1 (HMGB1) signaling modulates this interaction. PE was induced by pharmacologic nitric oxide deprivation during the last week of gestation (Nω-nitro-L-arginine methyl ester, L-NAME, 50 mg/kg/day, oral gavage). Compared with control rats, weaning PE rats revealed substantial rises in serum transaminases together with histopathological signs of hepatic cytoplasmic changes, portal inflammation, and central vein dilation. While gestational NSAIDs reversed the elevated transaminases, they had no effects (celecoxib, naproxen) or even worsened (diclofenac) the structural damage. Molecularly, celecoxib was the most effective NSAID in (i) reversing PE-evoked upregulation of hepatic HMGB1 gene expression and concomitant increments and decrements in mitogen-activated protein kinases MAPKERK and MAPKp38 expression, respectively, and (ii) elevating and suppressing serum interleukin-10 and tumor necrosis factor-α, respectively. Alternatively, rises in serum interleukin-1β and shifts in macrophage polarization towards an inflammatory phenotype caused by PE were comparably diminished by all NSAIDs. The data disclose an advantageous therapeutic potential for gestational celecoxib over diclofenac or naproxen in controlling hepatic dysfunction and HMGB1-interrelated inflammatory and oxidative sequels of PE.

Ferroptosis in hepatocellular carcinoma: from bench to bedside

The most widespread type of liver cancer, HCC, is associated with disabled cellular death pathways. Despite therapeutic advancements, resistance to current systemic treatments (including sorafenib) compromises the prognosis of patients with HCC, driving the search for agents that might target novel cell death pathways. Ferroptosis, a form of iron-mediated nonapoptotic cell death, has gained considerable attention as a potential target for cancer therapy, especially in HCC. The role of ferroptosis in HCC is complex and diverse. On one hand, ferroptosis can contribute to the progression of HCC through its involvement in both acute and chronic liver conditions. In contrast, having ferroptosis affect HCC cells might be desirable. This review examines the role of ferroptosis in HCC from cellular, animal, and human perspectives while examining its mechanisms, regulation, biomarkers, and clinical implications.

Sphk1 regulates HMGB1 via HDAC4 and mediates epithelial pyroptosis in allergic rhinitis

Background

Allergic rhinitis (AR) is a global health issue affecting millions of individuals worldwide. Pyroptosis has emerged as a major player in the development of AR, and targeting its inhibition with specific drugs holds promise for AR treatment. However, a comprehensive understanding of the precise mechanisms underlying pyroptosis in AR remains to be explored, warranting further investigation.

Objective

This study aims to elucidate the roles of HMGB1, Sphk1, and HDAC4 in regulating human nasal epithelial cell (hNEC) pyroptosis and AR.

Methods

An in vitro AR cell culture model and an in vivo AR mouse model were established. Western blot, ELISA, histological staining, and flow cytometry were utilized to confirm the gene and protein expression. The interactions among Sphk1, HDAC4, and HMGB1 were validated through ChIP, Co-IP, and Dual-luciferase assay.

Results and conclusion

We identified that the expression levels of Sphk1, HMGB1, and inflammasome components, including IL-18, and IL-1β were elevated in AR patients and mouse models. Knockdown of Sphk1 inhibited hNEC pyroptosis induced by dust mite allergen. Overexpression of HDAC4 suppressed HMGB1-mediated pyroptosis in hNECs. In addition, HDAC4 was found to mediate the transcriptional regulation of HMGB1 via MEF2C, a transcription factor. Additionally, Sphk1 was shown to interact with CaMKII-δ, promoting the phosphorylation of HDAC4 and inhibiting its cytoplasmic translocation. Knockdown of HDAC4 reversed the effect of Sphk1 knockdown on pyroptosis. These discoveries offer a glimpse into the molecular mechanisms underlying AR and suggest potential therapeutic targets for the treatment of this condition.