IL6/adiponectin/HMGB1 feedback loop mediates adipocyte and macrophage crosstalk and M2 polarization after myocardial infarction.

Background: Differences in border zone contribute to different outcomes post-infarction, such as left ventricular aneurysm (LVA) and myocardial infarction (MI). LVA usually forms within 24 h of the onset of MI and may cause heart rupture; however, LVA surgery is best performed 3 months after MI. Few studies have investigated the LVA model, the differences in border zones between LVA and MI, and the mechanism in the border zone. Methods: The LVA, MI, and SHAM mouse models were used. Echocardiography, Masson's trichrome staining, and immunofluorescence staining were performed, and RNA sequencing of the border zone was conducted. The adipocyte-conditioned medium-treated hypoxic macrophage cell line and LVA and MI mouse models were employed to determine the effects of the hub gene, adiponectin (ADPN), on macrophages. Quantitative polymerase chain reaction (qPCR), Western blot analysis, transmission electron microscopy, and chromatin immunoprecipitation (ChIP) assays were conducted to elucidate the mechanism in the border zone. Human subepicardial adipose tissue and blood samples were collected to validate the effects of ADPN. Results: A novel, simple, consistent, and low-cost LVA mouse model was constructed. LVA caused a greater reduction in contractile functions than MI owing to reduced wall thickness and edema in the border zone. ADPN impeded cardiac edema and promoted lymphangiogenesis by increasing macrophage infiltration post-infarction. Adipocyte-derived ADPN promoted M2 polarization and sustained mitochondrial quality via the ADPN/AdipoR2/HMGB1 axis. Mechanistically, ADPN impeded macrophage HMGB1 inflammation and decreased interleukin-6 (IL6) and HMGB1 secretion. The secretion of IL6 and HMGB1 increased ADPN expression via STAT3 and the co-transcription factor, YAP, in adipocytes. Based on ChIP and Dual-Glo luciferase experiments, STAT3 promoted ADPN transcription by binding to its promoter in adipocytes. In vivo, ADPN promoted lymphangiogenesis and decreased myocardial injury after MI. These phenotypes were rescued by macrophage depletion or HMGB1 knockdown in macrophages. Supplying adipocytes overexpressing STAT3 decreased collagen disposition, increased lymphangiogenesis, and impaired myocardial injury. However, these effects were rescued after HMGB1 knockdown in macrophages. Overall, the IL6/ADPN/HMGB1 axis was validated using human subepicardial tissue and blood samples. This axis could serve as an independent factor in overweight MI patients who need coronary artery bypass grafting (CABG) treatment. Conclusion: The IL6/ADPN/HMGB1 loop between adipocytes and macrophages in the border zone contributes to different clinical outcomes post-infarction. Thus, targeting the IL6/ADPN/HMGB1 loop may be a novel therapeutic approach for cardiac lymphatic regulation and reduction of cell senescence post-infarction.

Immunological Signatures in Blood and Urine in 80 Individuals Hospitalized during the Initial Phase of COVID-19 Pandemic with Quantified Nicotine Exposure.

This research analyzes immunological response patterns to SARS-CoV-2 infection in blood and urine in individuals with serum cotinine-confirmed exposure to nicotine. Samples of blood and urine were obtained from a total of 80 patients admitted to hospital within 24 h of admission (tadm), 48 h later (t48h), and 7 days later (t7d) if patients remained hospitalized or at discharge. Serum cotinine above 3.75 ng/mL was deemed as biologically significant exposure to nicotine. Viral load was measured with serum SARS-CoV-2 S-spike protein. Titer of IgG, IgA, and IgM against S- and N-protein assessed specific antiviral responses. Cellular destruction was measured by high mobility group box protein-1 (HMGB-1) serum levels and heat shock protein 60 (Hsp-60). Serum interleukin 6 (IL-6), and ferritin gauged non-specific inflammation. The immunological profile was assessed with O-link. Serum titers of IgA were lower at tadm in smokers vs. nonsmokers (p = 0.0397). IgM at t48h was lower in cotinine-positive individuals (p = 0.0188). IgG did not differ between cotinine-positive and negative individuals. HMGB-1 at admission was elevated in cotinine positive individuals. Patients with positive cotinine did not exhibit increased markers of non-specific inflammation and tissue destruction. The blood immunological profile had distinctive differences at admission (MIC A/B↓), 48 h (CCL19↓, MCP-3↓, CD28↑, CD8↓, IFNγ↓, IL-12↓, GZNB↓, MIC A/B↓) or 7 days (CD28↓) in the cotinine-positive group. The urine immunological profile showed a profile with minimal overlap with blood as the following markers being affected at tadm (CCL20↑, CXCL5↑, CD8↑, IL-12↑, MIC A/B↑, GZNH↑, TNFRS14↑), t48h (CCL20↓, TRAIL↓) and t7d (EGF↑, ADA↑) in patients with a cotinine-positive test. Here, we showed a distinctive immunological profile in hospitalized COVID-19 patients with confirmed exposure to nicotine.

[Ligusticum cycloprolactam inhibits IL-1ß-induced apoptosis and inflammation of rat chondrocytes via HMGB1/TLR4/NF-κB signaling pathway].

Chondrocytes are unique resident cells in the articular cartilage, and the pathological changes of them can lead to the occurrence of osteoarthritis(OA). Ligusticum cycloprolactam(LIGc) are derivatives of Z-ligustilide(LIG), a pharmacodynamic marker of Angelica sinensis, which has various biological functions such as anti-inflammation and inhibition of cell apoptosis. However, its protective effect on chondrocytes in the case of OA and the underlying mechanism remain unclear. This study conducted in vitro experiments to explore the molecular mechanism of LIGc in protecting chondrocytes from OA. The inflammation model of rat OA chondrocyte model was established by using interleukin-1ß(IL-1ß) to induce. LIGc alone and combined with glycyrrhizic acid(GA), a blocker of the high mobility group box-1 protein(HMGB1)/Toll-like receptor 4(TLR4)/nuclear factor-kappa B(NF-κB) signaling pathway, were used to intervene in the model, and the therapeutic effects were systematically evaluated. The viability of chondrocytes treated with different concentrations of LIGc was measured by the cell counting kit-8(CCK-8), and the optimal LIGc concentration was screened out. Annexin V-FITC/PI apoptosis detection kit was employed to examine the apoptosis of chondrocytes in each group. The enzyme-linked immunosorbent assay(ELISA) was employed to measure the expression of cyclooxygenase-2(COX-2), prostaglandin-2(PGE2), and tumor necrosis factor-alpha(TNF-α) in the supernatant of chondrocytes in each group. Western blot was employed to determine the protein levels of B-cell lymphoma-2(Bcl-2), Bcl-2-associated X protein(Bax), caspase-3, HMGB1, TLR4, and NF-κB p65. The mRNA levels of HMGB1, TLR4, NF-κB p65, and myeloid differentiation factor 88(MyD88) in chondrocytes were determined by real-time fluorescent quantitative PCR(RT-qPCR). The safe concentration range of LIGc on chondrocytes was determined by CCK-8, and then the optimal concentration of LIGc for exerting the effect was clarified. Under the intervention of IL-1ß, the rat chondrocyte model of OA was successfully established. The modeled chondrocytes showed increased apoptosis rate, promoted expression of COX-2, PGE2, and TNF-α, up-regulated protein levels of Bax, caspase-3, HMGB1, TLR4, and NF-κB p65 and mRNA levels of HMGB1, TLR4, NF-κB p65, and MyD88, and down-regulated protein level of Bcl-2. However, LIGc reversed the IL-1ß-induced changes of the above factors. Moreover, LIGc combined with GA showed more significant reversal effect than LIGc alone. These fin-dings indicate that LIGc extracted and derived from the traditional Chinese medicine A. sinensis can inhibit the inflammatory response of chondrocytes and reduce the apoptosis of chondrocytes, and this effect may be related to the HMGB1/TLR4/NF-κB signaling pathway. The pharmacological effect of LIGc on protecting chondrocytes has potential value in delaying the progression of OA and improving the clinical symptoms of patients, and deserves further study.

HMGB1 prefers to interact with structural RNAs and regulates rRNA methylation modification and translation in HeLa cells.

BACKGROUND: High-mobility group B1 (HMGB1) is both a DNA binding nuclear factor modulating transcription and a crucial cytokine that mediates the response to both infectious and noninfectious inflammation such as autoimmunity, cancer, trauma, and ischemia reperfusion injury. HMGB1 has been proposed to control ribosome biogenesis, similar as the other members of a class of HMGB proteins. RESULTS: Here, we report that HMGB1 selectively promotes transcription of genes involved in the regulation of transcription, osteoclast differentiation and apoptotic process. Improved RNA immunoprecipitation by UV cross-linking and deep sequencing (iRIP-seq) experiment revealed that HMGB1 selectively bound to mRNAs functioning not only in signal transduction and gene expression, but also in axon guidance, focal adhesion, and extracellular matrix organization. Importantly, HMGB1-bound reads were strongly enriched in specific structured RNAs, including the domain II of 28S rRNA, H/ACA box snoRNAs including snoRNA63 and scaRNAs. RTL-P experiment showed that overexpression of HMGB1 led to a decreased methylation modification of 28S rRNA at position Am2388, Cm2409, and Gm2411. We further showed that HMGB1 overexpression increased ribosome RNA expression levels and enhanced protein synthesis. CONCLUSION: Taken together, our results support a model in which HMGB1 binds to multiple RNA species in human cancer cells, which could at least partially contribute to HMGB1-modulated rRNA modification, protein synthesis function of ribosomes, and differential gene expression including rRNA genes. These findings provide additional mechanistic clues to HMGB1 functions in cancers and cell differentiation.

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

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

Serum HMGB1 and Beclin 1 Levels in Patients with a Diagnosis of Schizophrenia. / Sizofreni Tanili Hastalarda Serum HMGB1 ve Beklin 1 Düzeyleri.

OBJECTIVE: It is known that inflammation plays a role in the etiopathogenesis of schizophrenia. In this study, we examined high mobility group box 1 protein (HMGB1) and Beclin 1 levels and their relationship with clinical variables in patients with schizophrenia. METHOD: Forty-three patients with schizophrenia and 43 healthy controls were included in this study. The patients were administered sociodemographic data form, the Positive Negative Symptoms Assessment Scale (PANSS) and the Clinical Global Impressions (CGI) scale. After the scales were filled, venous blood samples were taken from both the patient and control groups to measure serum HMGB1 and Beclin 1 levels. Serum samples obtained at the end of centrifugation were measured by Enzyme-Linked ImmunoSorbent Assay (ELISA) method. RESULTS: The mean serum HMGB1 levels were significantly increased and the mean serum Beclin 1 levels were significantly decreased in the schizophrenia group compared to the control group. In addition, a negative correlation was found between HMGB1 and Beclin 1 levels. CONCLUSION: In conclusion, current research shows that HMGB1 is increased and Beclin 1 is decreased in patients with schizophrenia, and these findings may contribute to the role of autophagy in the pathogenesis of schizophrenia.

Necrosis Links Neurodegeneration and Neuroinflammation in Neurodegenerative Disease.

The mechanisms of neuronal cell death in neurodegenerative disease remain incompletely understood, although recent studies have made significant advances. Apoptosis was previously considered to be the only mechanism of neuronal cell death in neurodegenerative diseases. However, recent findings have challenged this dogma, identifying new subtypes of necrotic neuronal cell death. The present review provides an updated summary of necrosis subtypes and discusses their potential roles in neurodegenerative cell death. Among numerous necrosis subtypes, including necroptosis, paraptosis, ferroptosis, and pyroptosis, transcriptional repression-induced atypical cell death (TRIAD) has been identified as a potential mechanism of neuronal cell death. TRIAD is induced by functional deficiency of TEAD-YAP and self-amplifies via the release of HMGB1. TRIAD is a feasible potential mechanism of neuronal cell death in Alzheimer's disease and other neurodegenerative diseases. In addition to induction of cell death, HMGB1 released during TRIAD activates brain inflammatory responses, which is a potential link between neurodegeneration and neuroinflammation.

Impact of microglia isolation and culture methodology on transcriptional profile and function.

BACKGROUND: Microglial isolation and culturing methods continue to be explored to maximize cellular yield, purity, responsiveness to stimulation and similarity to in vivo microglia. This study aims to evaluate five different microglia isolation methods-three variants of microglia isolation from neonatal mice and two variants of microglia isolation from adult mice-on transcriptional profile and response to HMGB1. METHODS: Microglia from neonatal mice, age 0-3 days (P0-P3) were isolated from mixed glial cultures (MGC). We included three variations of this protocol that differed by use of GM-CSF in culture (No GM-CSF or 500 pg/mL GM-CSF), and days of culture in MGC before microglial separation (10 or 21). Protocols for studying microglia from adult mice age 6-8 weeks included isolation by adherence properties followed by 7 days of culture with 100 ng/mL GM-CSF and 100 ng/mL M-CSF (Vijaya et al. in Front Cell Neurosci 17:1082180, 2023), or acute isolation using CD11b beads (Bordt et al. in STAR Protoc 1:100035, 2020. https://doi.org/10.1016/j.xpro.2020.100035 ). Purity, yield, and RNA quality of the isolated microglia were assessed by flow cytometry, hemocytometer counting, and Bioanalyzer, respectively. Microglial responsiveness to an inflammatory stimulus, HMGB1, was evaluated by measuring TNFα, IL1ß, and IFNß concentration in supernatant by ELISA and assessing gene expression patterns using bulk mRNA sequencing. RESULTS: All five methods demonstrated greater than 90% purity. Microglia from all cultures increased transcription and secretion of TNFα, IL1ß, and IFNß in response to HMGB1. RNA sequencing showed a larger number of differentially expressed genes in response to HMGB1 treatment in microglia cultured from neonates than from adult mice, with sparse changes among the three MGC culturing conditions. Additionally, cultured microglia derived from adult and microglia derived from MGCs from neonates display transcriptional signatures corresponding to an earlier developmental stage. CONCLUSION: These findings suggest that while all methods provided high purity, the choice of protocol may significantly influence yield, RNA quality, baseline transcriptional profile and response to stimulation. This comparative study provides valuable insights to inform the choice of microglial isolation and culture method.

GPR65 sensing tumor-derived lactate induces HMGB1 release from TAM via the cAMP/PKA/CREB pathway to promote glioma progression.

BACKGROUND: Lactate has emerged as a critical regulator within the tumor microenvironment, including glioma. However, the precise mechanisms underlying how lactate influences the communication between tumor cells and tumor-associated macrophages (TAMs), the most abundant immune cells in glioma, remain poorly understood. This study aims to elucidate the impact of tumor-derived lactate on TAMs and investigate the regulatory pathways governing TAM-mediated tumor-promotion in glioma. METHODS: Bioinformatic analysis was conducted using datasets from TCGA and CGGA. Single-cell RNA-seq datasets were analyzed by using UCSC Cell Browser and Single Cell Portal. Cell proliferation and mobility were evaluated through CCK8, colony formation, wound healing, and transwell assays. Western blot and immunofluorescence staining were applied to assess protein expression and cell distribution. RT-PCR and ELISA were employed to identify the potential secretory factors. Mechanistic pathways were explored by western blotting, ELISA, shRNA knockdown, and specific inhibitors and activators. The effects of pathway blockades were further assessed using subcutaneous and intracranial xenograft tumor models in vivo. RESULTS: Elevated expressions of LDHA and MCT1 were observed in glioma and exhibited a positive correlation with M2-type TAM infiltration. Lactate derived from glioma cells induced TAMs towards M2-subtype polarization, subsequently promoting glioma cells proliferation, migration, invasion, and mesenchymal transition. GPR65, highly expressed on TAMs, sensed lactate-stimulation in the TME, fueling glioma cells malignant progression through the secretion of HMGB1. GPR65 on TAMs triggered HMGB1 release in response to lactate stimulation via the cAMP/PKA/CREB signaling pathway. Disrupting this feedback loop by GPR65-knockdown or HMGB1 inhibition mitigated glioma progression in vivo. CONCLUSION: These findings unveil the intricate interplay between TAMs and tumor cells mediated by lactate and HMGB1, driving tumor progression in glioma. GPR65, selectively highly expressed on TAMs in glioma, sensed lactate stimulation and fostered HMGB1 secretion via the cAMP/PKA/CREB signaling pathway. Blocking this feedback loop presents a promising therapeutic strategy for GBM.

IL-12-Overexpressed Nanoparticles Suppress the Proliferation of Melanoma Through Inducing ICD and Activating DC, CD8+ T, and CD4+ T Cells.

Purpose: The drug resistance and low response rates of immunotherapy limit its application. This study aimed to construct a new nanoparticle (CaCO3-polydopamine-polyethylenimine, CPP) to effectively deliver interleukin-12 (IL-12) and suppress cancer progress through immunotherapy. Methods: The size distribution of CPP and its zeta potential were measured using a Malvern Zetasizer Nano-ZS90. The morphology and electrophoresis tentative delay of CPP were analyzed using a JEM-1400 transmission electron microscope and an ultraviolet spectrophotometer, respectively. Cell proliferation was analyzed by MTT assay. Proteins were analyzed by Western blot. IL-12 and HMGB1 levels were estimated by ELISA kits. Live/dead staining assay was performed using a Calcein-AM/PI kit. ATP production was detected using an ATP assay kit. The xenografts in vivo were estimated in C57BL/6 mice. The levels of CD80+/CD86+, CD3+/CD4+ and CD3+/CD8+ were analyzed by flow cytometry. Results: CPP could effectively express EGFP or IL-12 and increase ROS levels. Laser treatment promoted CPP-IL-12 induced the number of dead or apoptotic cell. CPP-IL-12 and laser could further enhance CALR levels and extracellular HMGB1 levels and decrease intracellular HMGB1 and ATP levels, indicating that it may induce immunogenic cell death (ICD). The tumors and weights of xenografts in CPP-IL-12 or laser-treated mice were significantly reduced than in controls. The IL-12 expression, the CD80+/CD86+ expression of DC from lymph glands, and the number of CD3+/CD8+T or CD3+/CD4+T cells from the spleen increased in CPP-IL-12-treated or laser-treated xenografts compared with controls. The levels of granzyme B, IFN-γ, and TNF-α in the serum of CPP-IL-12-treated mice increased. Interestingly, CPP-IL-12 treatment in local xenografts in the back of mice could effectively inhibit the growth of the distant untreated tumor. Conclusion: The novel CPP-IL-12 could overexpress IL-12 in melanoma cells and achieve immunotherapy to melanoma through inducing ICD, activating CD4+ T cell, and enhancing the function of tumor-reactive CD8+ T cells.

Hypochlorous acid derived from microglial myeloperoxidase could mediate high-mobility group box 1 release from neurons to amplify brain damage in cerebral ischemia-reperfusion injury.

Myeloperoxidase (MPO) plays critical role in the pathology of cerebral ischemia-reperfusion (I/R) injury via producing hypochlorous acid (HOCl) and inducing oxidative modification of proteins. High-mobility group box 1 (HMGB1) oxidation, particularly disulfide HMGB1 formation, facilitates the secretion and release of HMGB1 and activates neuroinflammation, aggravating cerebral I/R injury. However, the cellular sources of MPO/HOCl in ischemic brain injury are unclear yet. Whether HOCl could promote HMGB1 secretion and release remains unknown. In the present study, we investigated the roles of microglia-derived MPO/HOCl in mediating HMGB1 translocation and secretion, and aggravating the brain damage and blood-brain barrier (BBB) disruption in cerebral I/R injury. In vitro, under the co-culture conditions with microglia BV cells but not the single culture conditions, oxygen-glucose deprivation/reoxygenation (OGD/R) significantly increased MPO/HOCl expression in PC12 cells. After the cells were exposed to OGD/R, MPO-containing exosomes derived from BV2 cells were released and transferred to PC12 cells, increasing MPO/HOCl in the PC12 cells. The HOCl promoted disulfide HMGB1 translocation and secretion and aggravated OGD/R-induced apoptosis. In vivo, SD rats were subjected to 2 h of middle cerebral artery occlusion (MCAO) plus different periods of reperfusion. Increased MPO/HOCl production was observed at the reperfusion stage, accomplished with enlarged infarct volume, aggravated BBB disruption and neurological dysfunctions. Treatment of MPO inhibitor 4-aminobenzoic acid hydrazide (4-ABAH) and HOCl scavenger taurine reversed those changes. HOCl was colocalized with cytoplasm transferred HMGB1, which was blocked by taurine in rat I/R-injured brain. We finally performed a clinical investigation and found that plasma HOCl concentration was positively correlated with infarct volume and neurological deficit scores in ischemic stroke patients. Taken together, we conclude that ischemia/hypoxia could activate microglia to release MPO-containing exosomes that transfer MPO to adjacent cells for HOCl production; Subsequently, the production of HOCl could mediate the translocation and secretion of disulfide HMGB1 that aggravates cerebral I/R injury. Furthermore, plasma HOCl level could be a novel biomarker for indexing brain damage in ischemic stroke patients.

The HMGB1-RAGE axis in nucleus accumbens facilitates cocaine-induced conditioned place preference via modulating microglial activation.

INTRODUCTION: Repeated exposure to cocaine induces microglial activation. Cocaine exposure also induces a release of high mobility group box-1 (HMGB1) from neurons into the extracellular space in the nucleus accumbens (NAc). HMGB1 is an important late inflammatory mediator of microglial activation. However, whether the secretion of HMGB1 acts on microglia or contributes to cocaine addiction is largely unknown. METHODS: Rats were trained by intraperitoneal cocaine administration and cocaine-induced conditioned place preference (CPP). Expression of HMGB1 was regulated by viral vectors. Activation of microglia was inhibited by minocycline. Interaction of HMGB1 and the receptor for advanced glycation end products (RAGE) was disrupted by peptide. RESULTS: Cocaine injection facilitated HMGB1 signaling, together with the delayed activation of microglia concurrently in the NAc. Furthermore, the inhibition of HMGB1 or microglia activation attenuated cocaine-induced CPP. Box A, a specific antagonist to interrupt the interaction of HMGB1 and RAGE, abolished the expression of cocaine reward memory. Meanwhile, the inhibition of HMGB1-RAGE interaction suppressed cocaine-induced microglial activation, as well as the consolidation of cocaine-induced memory. CONCLUSION: All above results suggest that the neural HMGB1 induces activation of microglia through RAGE, which contributes to the consolidation of cocaine reward memory. These findings offer HMGB1-RAGE axis as a new target for the treatment of drug addiction.

Lupus autoantibodies initiate neuroinflammation sustained by continuous HMGB1:RAGE signaling and reversed by increased LAIR-1 expression.

Cognitive impairment is a frequent manifestation of neuropsychiatric systemic lupus erythematosus, present in up to 80% of patients and leading to a diminished quality of life. In the present study, we used a model of lupus-like cognitive impairment that is initiated when antibodies that crossreact with excitatory neuronal receptors penetrate the hippocampus, causing immediate, self-limited, excitotoxic death of hippocampal neurons, which is then followed by a significant loss of dendritic complexity in surviving neurons. This injury creates a maladaptive equilibrium that is sustained in mice for at least 1 year. We identified a feedforward loop of microglial activation and microglia-dependent synapse elimination dependent on neuronal secretion of high mobility group box 1 protein (HMGB1) which binds the receptor for advanced glycation end products (RAGE) and leads to microglial secretion of C1q, upregulation of interleukin-10 with consequent downregulation of leukocyte-associated immunoglobulin-like receptor 1 (LAIR-1), an inhibitory receptor for C1q. Treatment with a centrally acting angiotensin-converting enzyme inhibitor or with an angiotensin-receptor blocker restored a healthy equilibrium, microglial quiescence and intact spatial memory.

High-mobility group box 1 increases platelet surface P2Y12 and platelet activation in sickle cell disease.

Thrombosis and inflammation are intimately linked and synergistically contribute to the pathogenesis of numerous thromboinflammatory diseases, including sickle cell disease (SCD). While platelets are central to thrombogenesis and inflammation, the molecular mechanisms of crosstalk between the 2 remain elusive. High-mobility group box 1 (HMGB1) regulates inflammation and stimulates platelet activation through Toll-like receptor 4. However, it remains unclear whether HMGB1 modulates other thrombotic agonists to regulate platelet activation. Herein, using human platelets, we demonstrate that HMGB1 significantly enhanced ADP-mediated platelet activation. Furthermore, inhibition of the purinergic receptor P2Y12 attenuated HMGB1-dependent platelet activation. Mechanistically, we show that HMGB1 stimulated ADP secretion, while concomitantly increasing P2Y12 levels at the platelet membrane. We show that in SCD patients, increased plasma HMGB1 levels were associated with heightened platelet activation and surface P2Y12 expression. Treatment of healthy platelets with plasma from SCD patients enhanced platelet activation and surface P2Y12, and increased sensitivity to ADP-mediated activation, and these effects were linked to plasma HMGB1. We conclude that HMGB1-mediated platelet activation involves ADP-dependent P2Y12 signaling, and HMGB1 primes platelets for ADP signaling. This complementary agonism between ADP and HMGB1 furthers the understanding of thromboinflammatory signaling in conditions such as SCD, and provides insight for therapeutic P2Y12 inhibition.

The Effect of HMGB1 and HMGB2 on Transcriptional Regulation Differs in Neuroendocrine and Adenocarcinoma Models of Prostate Cancer.

Human high-mobility group-B (HMGB) proteins regulate gene expression in prostate cancer (PCa), a leading cause of oncological death in men. Their role in aggressive PCa cancers, which do not respond to hormonal treatment, was analyzed. The effects of HMGB1 and HMGB2 silencing upon the expression of genes previously related to PCa were studied in the PCa cell line PC-3 (selected as a small cell neuroendocrine carcinoma, SCNC, PCa model not responding to hormonal treatment). A total of 72% of genes analyzed, using pre-designed primer panels, were affected. HMGB1 behaved mostly as a repressor, but HMGB2 as an activator. Changes in SERPINE1, CDK1, ZWINT, and FN1 expression were validated using qRT-PCR after HMGB1 silencing or overexpression in PC-3 and LNCaP (selected as an adenocarcinoma model of PCa responding to hormonal treatment) cell lines. Similarly, the regulatory role of HMGB2 upon SERPINE1, ZWINT, FN1, IGFPB3, and TYMS expression was validated, finding differences between cell lines. The correlation between the expression of HMGB1, HMGB2, and their targets was analyzed in PCa patient samples and also in PCa subgroups, classified as neuroendocrine positive or negative, in public databases. These results allow a better understanding of the role of HMGB proteins in PCa and contribute to find specific biomarkers for aggressive PCa.

Analysis of changes in high-mobility group box 1, receptor for advanced glycation endproducts, and T helper 17/regulatory T balance in severe preeclampsia with acute heart failure.

We measured the levels of High-Mobility Group Box 1 (HMGB1), Receptor for Advanced Glycation Endproducts (RAGE), T Helper 17 cells (Th17), Regulatory T cells (Treg), and related cytokines in the peripheral blood of patients with severe preeclampsia (SPE) complicated with acute heart failure (AHF) to explore the expression changes in these indicators. In total, 96 patients with SPE admitted to Gansu Provincial Maternity and Child-care Hospital between June 2020 and June 2022 were included in the study. The patients were divided into SPE+AHF (40 patients) and SPE (56 patients) groups based on whether they suffered from AHF. Additionally, 56 healthy pregnant women who either received prenatal examinations or were admitted to our hospital for delivery during the same period were selected as the healthy control group. An enzyme-linked immunosorbent assay was performed to detect the expression levels of HMGB1, RAGE, interleukin (IL)-17, IL-6, transforming growth factor ß (TGF-ß), IL-10, and NT-proBNP in plasma. Flow cytometry was employed to determine the percentages of Th17 and Treg cells. Compared to the healthy control group, the SPE+AHF and SPE groups had higher plasma levels of HMGB1 and RAGE expression, higher Th17 percentage and Th17/Treg ratio, and lower Treg percentage. Compared to the SPE group, the SPE+AHF group had higher plasma levels of HMGB1 and RAGE expression, higher Th17 percentage and Th17/Treg ratio, and lower Treg percentage (P < .05). In patients with SPE with AHF, plasma HMGB1 was positively correlated with RAGE, Th17, Th17/Treg, IL-17, and IL-6 and was negatively correlated with TGF-ß and IL-10 (P < .05). Our findings revealed that patients with SPE with AHF had elevated levels of HMGB1 and RAGE while exhibiting Th17/Treg immune imbalance, suggesting that the abnormal expression of these indicators may be involved in the pathogenesis of SPE with AHF.

LncRNA AA465934 Improves Podocyte Injury by Promoting Tristetraprolin-Mediated HMGB1 DownRegulation in Diabetic Nephropathy.

Although LncRNA AA465934 expression is reduced in high glucose (HG)-treated podocytes, its role in HG-mediated podocyte injury and diabetic nephropathy (DN) remains unknown. Herein, we investigated the role of AA465934 in HG-mediated podocyte injury and DN using a spontaneous type II diabetic nephropathy (T2DN) model. The model was created by injecting AA465934 overexpressed adeno-associated virus (AAV) or control into mice. The levels of renal function, proteinuria, renal structural lesions, and podocyte apoptosis were then examined. Furthermore, AA465934 and autophagy levels, as well as tristetraprolin (TTP) and high mobility group box 1 (HMGB1) expression changes were detected. We also observed podocyte injury and the binding ability of TTP to E3 ligase proviral insertion in murine lymphomas 2 (PIM2), AA465934, or HMGB1. According to the results, AA465934 improved DN progression and podocyte damage in T2DN mice. In addition, AA465934 bound to TTP and inhibited its degradation by blocking TTP-PIM2 binding. Notably, TTP knock-down blocked the ameliorating effects of AA465934 and TTP bound HMGB1 mRNA, reducing its expression. Overexpression of HMGB1 inhibited the ability of AA465934 and TTP to improve podocyte injury. Furthermore, AA465934 bound TTP, inhibiting TTP-PIM2 binding, thereby suppressing TTP degradation, downregulating HMGB1, and reversing autophagy downregulation, ultimately alleviating HG-mediated podocyte injury and DN. Based on these findings, we deduced that the AA465934/TTP/HMGB1/autophagy axis could be a therapeutic avenue for managing podocyte injury and DN.

Isolation and microbial transformation of tea sapogenin from seed pomace of Camellia oleifera with anti-inflammatory effects.

In the current study, tea saponin, identified as the primary bioactive constituent in seed pomace of Camellia oleifera Abel., was meticulously extracted and hydrolyzed to yield five known sapogenins: 16-O-tiglogycamelliagnin B (a), camelliagnin A (b), 16-O-angeloybarringtogenol C (c), theasapogenol E (d), theasapogenol F (e). Subsequent biotransformation of compound a facilitated the isolation of six novel metabolites (a1-a6). The anti-inflammatory potential of these compounds was assessed using pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns molecules (DAMPs)-mediated cellular inflammation models. Notably, compounds b and a2 demonstrated significant inhibitory effects on both lipopolysaccharide (LPS) and high-mobility group box 1 (HMGB1)-induced inflammation, surpassing the efficacy of the standard anti-inflammatory agent, carbenoxolone. Conversely, compounds d, a3, and a6 selectivity targeted endogenous HMGB1-induced inflammation, showcasing a pronounced specificity. These results underscore the therapeutic promise of C. oleifera seed pomace-derived compounds as potent agents for the management of inflammatory diseases triggered by infections and tissue damage.

Glucose regulates the HMGB1 signaling pathway through SIRT1 in glioma.

BACKGROUND: Glucose is a fundamental substance for numerous cancers, including glioma. However, its influence on tumor cells regulatory mechanisms remains uncertain. SIRT1 is a regulator of deacetylation and a key player in the progression of malignant tumors. The objective of this study was to examine the role of glucose and SIRT1 in glioma. METHODS: This study investigated the association of SIRT1 expression with clinicopathological features and prognosis in glioma patients using the TCGA database. The Western blotting technique was used to identify the expression of SIRT1 protein in glioma cells. The study also examined the impact of differing glucose concentrations on the biological functions of glioma cells. The study investigated the expression of SIRT1 and HMGB1 signaling pathways in glioma. Additionally, resilience experiments were conducted utilizing SRT1720. RESULTS: SIRT1 is a gene that suppresses tumors and is low expressed in gliomas. Low expression of this gene is strongly linked to a poor prognosis in patients with glioma. High concentrations of glucose can promote the proliferation, migration, and invasion of glioma cells, while also inhibiting apoptosis. The findings of this mechanistic study provide evidence that glucose can down-regulate SIRT1 expression, leading to increased levels of acetylated HMGB1. This in turn promotes the ex-nuclear activation of HMGB1 and associated signaling pathways, ultimately driving glioma malignancy. CONCLUSION: Glucose has the ability to regulate the HMGB1 associated signaling pathway through SIRT1, thus promoting glioma progression. This holds significant research value.

M1 Macrophage-Derived Exosome LncRNA PVT1 Promotes Inflammation and Pyroptosis of Vascular Smooth Muscle Cells in Abdominal Aortic Aneurysm by Inhibiting miR-186-5p and Regulating HMGB1.

Abdominal aortic aneurysm (AAA) is a chronic vascular degenerative disease. Vascular smooth muscle cells (VSMCs) are essential for maintaining the integrity of healthy blood vessels. Macrophages play an important role in the inflammatory process of AAA. However, the effect of macrophage-derived exosome LncRNA PVT1 on VSMCs is unclear. Exosomes from M1 macrophages (M1φ-exos) were isolated and identified. The expression of LncRNA PVT1 in M1φ-exos was determined. AAA cell model was constructed by treating VSMCs with Ang-II. AAA cell model was treated with M1φ exosomes transfected with si-LncRNA PVT1 (M1φsi-LncRNA PVT1-exo). VSMCs were transfected with miR-186-5p mimic and oe-HMGB1. Cell viability was detected by CCK-8. The accumulation of LDH was detected by ELISA. Western blot was used to detect the expression of HMGB1, inflammatory factors (IL-6, TNF-α and IL-1ß) and pyroptosis-related proteins (GSDMD, N-GSDMD, ASC, NLRP3, Caspase-1 and Cleaved-Capase-1). Cell pyroptosis rate was detected by flow cytometry. At the same time, the targeting relationship between miR-186-5p and LncRNA PVT1 and HMGB1 was verified by double fluorescein experiment. Exosomes from M1φ were successfully extracted. The expression of LncRNA PVT1 in M1φ-exos was significantly increased. M1φ-exo promotes inflammation and pyroptosis of VSMCs. M1φsi-LncRNA PVT1-exos inhibited the inflammation and pyroptosis of VSMCs. LncRNA PVT1 can sponge miR-186-5p mimic to regulate HMGB1 expression. MiR-186-5p mimic further inhibited inflammation and pyroptosis induced by M1φsi-LncRNA PVT1-exos. However, oe-HMGB1 could inhibit the reversal effect of miR-186-5p mimic. LncRNA PVT1 in exosomes secreted by M1φ can regulate HMGB1 by acting as ceRNA on sponge miR-186-5p, thereby promoting cell inflammatory and pyroptosis and accelerating AAA progression.