Expression Of High Mobility Group Box Protein 1 Research Articles

Ethyl pyruvate ameliorates acute respiratory distress syndrome in mice

Acute respiratory distress syndrome (ARDS) became a focus of intensive research due to its death toll during the Covid-19 pandemic. An uncontrolled and excessive inflammatory response mediated by proinflammatory molecules such as high mobility group box protein 1 (HMGB1), IL-6, and TNF mounts as a response to infection. In this study, ethyl pyruvate (EP), a known inhibitor of HMGB1, was tested in the model of murine ARDS induced in C57BL/6 mice by intranasal administration of polyinosinic:polycytidylic acid (poly(I:C)). Intraperitoneal administration of EP ameliorated the ARDS-related histopathological changes in the lungs of poly(I:C)-induced ARDS and decreased numbers of immune cells in the lungs, broncho-alveolar lavage fluid and draining lymph nodes (DLN). Specifically, fewer CD8+ T cells and less activated CD4+ T cells were observed in DLN. Consequently, the lungs of EP-treated animals had fewer damage-inflicting CD8+ cells and macrophages. Additionally, the expression and production of proinflammatory cytokines, IL-17, IFN-γ and IL-6 were downregulated in the lungs. The expression of chemokine CCL5 which recruits immune cells into the lungs was also reduced. Finally, EP downregulated the expression of HMGB1 in the lungs. Our results imply that EP should be further evaluated as a potential candidate for ARDS therapy.

HMGB1 mediates lipopolysaccharide-induced macrophage autophagy and pyroptosis

Autophagy and pyroptosis of macrophages play important protective or detrimental roles in sepsis. However, the underlying mechanisms remain unclear. High mobility group box protein 1 (HMGB1) is associated with both pyroptosis and autophagy. lipopolysaccharide (LPS) is an important pathogenic factor involved in sepsis. Lentivirus-mediated HMGB1 shRNA was used to inhibit the expression of HMGB1. Macrophages were treated with acetylation inhibitor (AA) to suppress the translocation of HMGB1 from the nucleus to the cytosol. Autophagy and pyroptosis-related protein expressions were detected by Western blot. The levels of caspase-1 activity were detected and the rate of pyroptotic cells was detected by flow cytometry. LPS induced autophagy and pyroptosis of macrophages at different stages, and HMGB1 downregulation decreased LPS-induced autophagy and pyroptosis. Treatment with acetylation inhibitor (anacardic acid) significantly suppressed LPS-induced autophagy, an effect that was not reversed by exogenous HMGB1, suggesting that cytoplasmic HMGB1 mediates LPS-induced autophagy of macrophages. Anacardic acid or an anti-HMGB1 antibody inhibited LPS-induced pyroptosis of macrophages. HMGB1 alone induced pyroptosis of macrophages and this effect was inhibited by anti-HMGB1 antibody, suggesting that extracellular HMGB1 induces macrophage pyroptosis and mediates LPS-induced pyroptosis. In summary, HMGB1 plays different roles in mediating LPS-induced autophagy and triggering pyroptosis according to subcellular localization.

RAGE and HMGB1 expressions in fetal membranes of premature rupture of membranes patients

BACKGROUND Premature rupture of membranes (PROM) often occurs in pregnancy. The fetal membrane weakening is caused by inflammation involving receptor activation for advanced glycation end-products (RAGE) and high mobility group box protein 1 (HMGB1). The associations between RAGE and HMGB1 with PROM are rarely studied. Hence, this study aimed to determine those associations in fetal membranes with PROM occurrence.
 METHODS This case-control study was conducted at Dr. Ramelan Central Naval Hospital, Surabaya, Indonesia, from August to November 2019. The subjects, determined using a non-probability sampling method (a saturated sample), were divided into PROM and normal pregnancy with intact fetal membranes (control) groups. Fetal membrane specimens were collected during vaginal and cesarean section deliveries. The expressions of RAGE and HMGB1 were determined using the immunohistochemical method and further analyzed using the Mann–Whitney U test.
 RESULTS The expression of RAGE in fetal membranes with PROM was significantly higher than the control (52.74% versus 14.9% expression/mm2, p<0.001), as well as the expression of HMGB1 (45.9% versus 8.5% expression/mm2, p<0.001).
 CONCLUSIONS The higher expressions of RAGE and HMGB1 in fetal membranes were associated with PROM.

Ac2‑26 alleviates hepatic ischemia‑reperfusion injury based on inhibiting the positive feedback loop of HMGB1/TLR4/NF‑κB/neutrophils.

Inflammation is one of the most crucial mechanism underlying hepatic ischemia-reperfusion injury (HIRI). Several studies have shown that Ac2-26, the active N-terminal peptide of Annexin A1, could modulate anti-inflammatory processes and protect the organs from ischemia-reperfusion injury (IRI). However the effects of Ac2-26 on an HIRI model have not been reported to date. The purpose of the present study was to determine whether Ac2-26 pretreatment could protect hepatocytes against acute HIRI by inhibiting neutrophil infiltration through regulation of the high mobility group box protein 1 (HMGB1)/Toll-like receptor 4 (TLR4)/NF-κB signaling pathway. To this end, a total of 72 adult C57BL/6 mice were randomly divided into sham operation (sham), ischemia-reperfusion (I/R), I/R + Ac2-26 and Ac2-26 groups. The HIRI model was established by occluding the branch of the hepatic pedicle to the left and median liver lobes with an atraumatic vascular clamp for 45 min, followed by reperfusion for 24 h. The expression of HMGB1, TLR4, NF-κB, IκBα and lymphocyte antigen 6 complex locus G6D (Ly6G) was detected using reverse transcription-quantitative PCR, western blotting and immunohistochemical staining; serum levels of HMGB1 were evaluated using an enzyme-linked immunosorbent assay. Flow cytometry was used to detect the proportion of neutrophil. The results indicated that Ac2-26 preconditioning rescued hepatocyte dysfunctions induced by HIRI. In addition, HIRI was associated with a significant increase in HMGB1 expression and release, accompanied by increased expression of TLR4, which was significantly inhibited by Ac2-26. Furthermore, the expression of phosphorylated (p)-NF-κB and the ratio of p-NF-κB to NF-κB were markedly increased, while the expression of IκBα was decreased in the I/R group compared with those in the sham group; however, these effects were reversed by Ac2-26 administration. Additionally, Ac2-26 administration significantly inhibited neutrophil infiltration and resulted in low levels of neutrophils and Ly6G as well as reduced myeloperoxidase activity. Taken together, these results indicated that Ac2-26 pretreatment serves a protective role against HIRI by regulating the HMGB1/TLR4/NF-κB signaling pathway and inhibiting neutrophil infiltration.

TLR2, TLR4, and NLRP3 mediated the balance between host immune-driven resistance and tolerance in Staphylococcus aureus-infected mice

Staphylococcus aureus (S. aureus) is a gram-positive pathogen that can cause infectious diseases in mammals. S. aureus-induced host innate immune responses have a relationship with Toll-like receptor 2 (TLR2), TLR4, and Nod-like receptor pyrin domain-containing protein 3 (NLRP3). However, the detailed roles of TLR2, TLR4, and NLRP3 in regulating the host inflammatory response to S. aureus infection remain unclear. Our data indicated that the S. aureus-induced mortality was aggravated by deficiency of TLR2, TLR4, and NLRP3 in mice. In the subsequent experiment, we found that during S. aureus infection, the roles of TLR2, TLR4, and NLRP3 seemed to be different at multiple timepoints. The deficiency of TLR2, TLR4, or NLRP3 attenuated the expression of High-mobility group box protein 1 (HMGB1) and Hyaluronic acid-binding protein 2 (HABP2), which is accompanied by decreased proinflammatory cytokine (TNF-α), chemokine (RANTES), and anti-inflammatory cytokine (IL-10) production in lungs and serum at 3 h and 6 h post-infection. However, with S. aureus infection prolonged (24 h post-infection), the trend was diametrically opposite. The results showed that deficiency of TLR2, TLR4, or NLRP3 aggravated HABP2 and HMGB1 expression, which is accompanied by enhanced proinflammatory cytokine (TNF-α), chemokine (RANTES), and anti-inflammatory cytokine (IL-10) production in lungs and serum. These results were consistent with the data observed in S. aureus-infected bone marrow-derived macrophages (BMDMs). All these results suggested that during S. aureus infection, TLR2, TLR4, and NLRP3 has time-dependent effect in regulating the balance between immune-driven resistance and tolerance.

Increased expression of HMGB1 in the implantation phase endometrium is related to recurrent implantation failure.

Impaired endometrial receptivity was the main cause of recurrent implantation failure (RIF); however, its underlying mechanisms had not been elucidated. This study aimed to determine the expression level of high-mobility group box protein 1 (HMGB1) in the endometrium with RIF and its effect on endometrial receptivity. Genome-wide expression profiling, real-time reverse transcription PCR, immunohistochemical staining, western blot, and in vitro assays were performed in this study. We found that HMGB1 expression was significantly decreased in the implantation phase endometrium in the control group (patients with tubal infertility and successfully achieve conception after the first embryo transfer) (P = 0.006). However, the expression levels of HMGB1 mRNA and protein were significantly upregulated during the implantation phase in endometrial tissues obtained from patients with RIF compared to that in the control group (P = 0.001), consistent with the results of the genome-wide expression profiling. Moreover, in vitro assays showed that increased expression of HMGB1 in human endometrial epithelial cells dramatically displayed a marked deficiency in supporting blastocysts and human embryonic JAR cells adhesion, which mimic the process of embryo adhesion. These findings strongly indicated that increased HMGB1 levels suppressed the epithelial cell adhesion capability, therefore contributing to impaired endometrial receptivity in patients with recurrent implantation failure, which can be used as a target for the recognition and treatment of recurrent implantation failure in clinical practice.

Translocation of High Mobility Group Box 1 From the Nucleus to the Cytoplasm in Depressed Patients With Epilepsy.

Depression is a common psychiatric comorbidity in patients with epilepsy, especially those with temporal lobe epilepsy (TLE). The aim of this study was to assess changes in high mobility group box protein 1 (HMGB1) expression in epileptic patients with and without comorbid depression. Sixty patients with drug-resistant TLE who underwent anterior temporal lobectomy were enrolled. Anterior hippocampal samples were collected after surgery and analyzed by immunofluorescence (n = 7/group). We also evaluated the expression of HMGB1 in TLE patients with hippocampal sclerosis and measured the level of plasma HMGB1 by enzyme-linked immunosorbent assay. The results showed that 28.3% of the patients (17/60) had comorbid depression. HMGB1 was ubiquitously expressed in all subregions of the anterior hippocampus. The ratio of HMGB1-immunoreactive neurons and astrocytes was significantly increased in both TLE patients with hippocampal sclerosis and TLE patients with comorbid depression compared to patients with TLE only. The ratio of cytoplasmic to nuclear HMGB1-positive neurons in the hippocampus was higher in depressed patients with TLE than in nondepressed patients, which suggested that more HMGB1 translocated from the nucleus to the cytoplasm in the depressed group. There was no significant difference in the plasma level of HMGB1 among patients with TLE alone, TLE with hippocampal sclerosis, and TLE with comorbid depression. The results of the study revealed that the translocation of HMGB1 from the nucleus to the cytoplasm in hippocampal neurons may play a previously unrecognized role in the initiation and amplification of epilepsy and comorbid depression. The direct targeting of neural HMGB1 is a promising approach for anti-inflammatory therapy.

The long intergenic non-protein coding RNA 472 (LINC00472) aggravates neuropathic pain through the microRNA-300/high mobility group box protein 1 axis: a study using the chronic constrictive injury rat model.

This study investigated the role and molecular mechanisms of the long intergenic non-protein coding RNA 472 (LINC00472) in neuropathic pain using a chronic constrictive injury (CCI) rat model. CCI rat model was established and PC12 cells were induced by LPS to simulate neuropathological injury in vivo and in vitro. The levels of LINC00472, miR-300, and high mobility group box protein 1 (HMGB1) in the spinal cord tissue of CCI rats and PC12 pheochromocytoma cells were assessed by qRT-PCR and western blot. The effects of LINC00472 on neuropathic pain in the CCI rats were observed by their pain behavior. ELISA was used to detect the levels of inflammatory cytokines in rat tissues and cells. The molecular mechanisms of LINC00472 were verified by luciferase experiments, RNA immunoprecipitation, and RNA pull down assays. The expression of LINC00472 and HMGB1 were upregulated, and the expression of miR-300 was downregulated in the spinal cord tissues of CCI rats and in PC12 cells. The upregulation of LINC00472 in CCI rats significantly induced the occurrence of neuropathic pain. In addition, downregulation of LINC00472 inhibited the inflammatory response of CCI rats and PC12 cells. This study identified miR-300 as a target gene of LINC00472, and HMGB1 as the target gene of miR-300. Further experiments confirmed that the expression of anti-miR-300 could partially reverse the anti-inflammatory effects and the reduction of neuropathic pain induced by low expression of LINC00472. LINC00472 promotes the progression of neuropathic pain by reducing miR-300 expression and increasing HMGB1 expression. The LINC00472/miR-300/HMGB1 axis may be a novel therapeutic target for neuropathic pain.

HMGB1 Promotes Resistance to Doxorubicin in Human Hepatocellular Carcinoma Cells by Inducing Autophagy via the AMPK/mTOR Signaling Pathway.

Chemoresistance remains as a major hindrance in the treatment of hepatocellular carcinoma (HCC). High mobility group box protein 1 (HMGB1) enhances autophagic flux and protects tumor cells from apoptosis, which results in acquired drug resistance. However, the exact mechanisms underlying HMGB1-modulated autophagy in HCC chemoresistance remain to be defined. In the present study, we found that administration of doxorubicin (DOX) significantly promoted HMGB1 expression and induced HMGB1 cytoplasmic translocation in human HCC cell lines BEL7402 and SMMC7721, which enhanced autophagy that contributes to protecting HCC cells from apoptosis and increasing drug resistance. Moreover, we observed HMGB1 translocation and elevation of autophagy in DOX-resistant BEL7402 and SMMC7721 cells. Additionally, inhibition of HMGB1 and autophagy increased the sensitivities of BEL-7402 and SMMC-7721 cells to DOX and re-sensitized their DOX-resistant cells. Subsequently, we confirmed with HMGB1 regulated autophagy by activating the 5ʹ adenosine monophosphate-activated protein kinase (AMPK)/mTOR pathway. In summary, our results indicate that HMGB1 promotes acquired DOX resistance in DOX-treated BEL7402 and SMMC7721 cells by enhancing autophagy through the AMPK/mTOR signaling pathway. These findings provide the proof-of-concept that HMGB1 inhibitors might be an important targeted treatment strategy for HCC.

Magnoflorine Alleviates "M1" Polarized Macrophage-Induced Intervertebral Disc Degeneration Through Repressing the HMGB1/Myd88/NF-κB Pathway and NLRP3 Inflammasome.

Intervertebral disc degeneration (IDD) is related to the deterioration of nucleus pulposus (NP) cells due to hypertrophic differentiation and calcification. The imbalance of pro-inflammatory (M1 type) and anti-inflammatory (M2 type) macrophages contributes to maintaining tissue integrity. Here, we aimed to probe the effect of Magnoflorine (MAG) on NP cell apoptosis mediated by “M1” polarized macrophages. THP-1 cells were treated with lipopolysaccharide (LPS) to induce “M1” polarized macrophages. Under the treatment with increasing concentrations of MAG, the expression of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, IL-18), high mobility group box protein 1 (HMGB1), as well as myeloid differentiation factor 88 (MyD88), nuclear factor kappa B (NF-κB) and NOD-like receptor 3 (NLRP3) inflammasomes in THP-1 cells were determined. What’s more, human NP cells were treated with the conditioned medium (CM) from THP-1 cells. The NP cell viability and apoptosis were evaluated. Western blot (WB) was adopted to monitor the expression of apoptosis-related proteins (Bax, Caspase3, and Caspase9), catabolic enzymes (MMP-3, MMP-13, ADAMTS-4, and ADAMTS-5), and extracellular matrix (ECM) compositions (collagen II and aggrecan) in NP cells. As a result, LPS evidently promoted the expression of pro-inflammatory cytokines and HMGB1, the MyD88-NF-κB activation, and the NLRP3 inflammasome profile in THP-1 cells, while MAG obviously inhibited the "M1″ polarization of THP-1 cells. After treatment with “M1” polarized THP-1 cell CM, NP cell viability was decreased, while cell apoptosis, the pro-inflammatory cytokines, apoptosis-related proteins, and catabolic enzymes were distinctly up-regulated, and ECM compositions were reduced. After treatment with MAG, NP cell damages were dramatically eased. Furthermore, MAG dampened the HMGB1 expression and inactivated the MyD88/NF-κB pathway and NLRP3 inflammasome in NP cells. In conclusion, this study confirmed that MAG alleviates “M1” polarized macrophage-mediated NP cell damage by inactivating the HMGB1-MyD88-NF-κB pathway and NLRP3 inflammasome, which provides a new reference for IDD treatment.

Lactobacillus acidophilus ATCC 4356 Alleviates Renal Ischemia-Reperfusion Injury Through Antioxidant Stress and Anti-inflammatory Responses and Improves Intestinal Microbial Distribution.

Background: Ischemia–reperfusion injury (IRI) is one of the main causes of acute kidney injury. Our previous results have shown that anti-oxidative stress decreased in the renal IRI model. This study aimed to investigate the effect of Lactobacillus acidophilus ATCC 4356 on oxidative stress, inflammation, and intestinal flora in renal IRI.Methods: The model of renal IRI was established by cross-clamping the renal pedicle with non-traumatic vascular forceps. H&E staining was applied to observe the damage of kidney tissue in each group. The concentrations of serum blood urea nitrogen (BUN), creatinine (Cre), superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA) were detected by biochemical kit. ELISA measured the concentrations of interleukin (IL)-1β, IL-8, IL-4, and IL-10. qRT-PCR was performed to detect molecular expressions of ATCC 4356, oxidative stress-related factors [nuclear factor-related factor 2 (Nrf2), heme oxygenase 1 (HO-1)], inflammatory factors [tumor necrosis factor (TNF)-α, IL-1β, IL-8, interferon (IFN)-γ, IL-4, IL-10], and apoptosis-related factors [caspase 3, Bax, Bcl2, high-mobility group box protein 1 (HMGB1)]. Except for ATCC 4356, the protein expression of the above indicators was detected by Western blot. The apoptosis level of renal tissue cells was detected by TdT-mediated dUTP nick end labeling (TUNEL). 16S rDNA gene sequencing was used to detect the changes of microbial species in the contents of the duodenum and screen out the differentially expressed flora.Results: Both the glomeruli and renal tubules of ischemia/reperfusion (I/R) mice were severely damaged. H&E result displayed that L. acidophilus ATCC 4356 attenuated the infiltration of inflammatory cells caused by I/R. ATCC 4356 reduced the high expression of BUN and Cre in I/R mice with a dose effect. It also reduced the high expression of MDA, TNF-α, IL-1β, IL-8, IFN-γ, caspase 3, Bax, and HMGB1 in I/R mice, while it increased the low expression of SOD, GSH, Nrf2, HO-1, IL-4, IL-10, and Bcl2 in I/R mice. ATCC 4356 inhibited the high level of apoptosis in the kidney tissue of I/R mice. In IRI mice, the top 3 different gut microbiota were Helicobacter, cultivated_bacterium, and k__Bacteria_ASV_3 compared with sham mice. Oral L. acidophilus ATCC 4356 reversed this change.Conclusion: L. acidophilus ATCC 4356 attenuated renal IRI through anti-oxidative stress and anti-inflammatory response and improved the intestinal microbial distribution.

MiR-129-5p alleviates LPS-induced acute kidney injury via targeting HMGB1/TLRs/NF-kappaB pathway

IntroductionThe present study aimed to investigate whether miR-129-5p can regulate high-mobility group box protein 1 (HMGB1)-modulated TLRs/NF-kappaB inflammatory pathway that contributed to lipopolysaccharide (LPS)-induced podocyte apoptosis and acutekidneyinjury (AKI). Material and methodsIn vitro and in vivo models of sepsis were simulated using LPS-administrated podocytes and mice, respectively. The effects of LPS, mR-129-5p mimics and short hairpin RNA of HMGB1 (sh-HMGB1) on podocyte apoptosis were monitored using TUNEL staining. Protein expression was measured using western blotting. Survival outcomes were analyzed in septic mice with agomir-mR-129-5p administration. ResultsWe observed that stimulation of podocytes with LPS significantly inhibits the expression of miR-129-5p, and overexpression of miR-129-5p protects against LPS-induced podocyte damage, over-activation of inflammatory response and apoptosis. In a mouse model, agomir-miR-129-5p administration significantly improves the survival outcomes in septic mice and LPS-induced AKI. Mechanically, LPS-induced the elevation of HMGB1, TLR2, TLR4 and nuclear NF-κB protein expression in vitro and in vivo are restrained by the overexpression of miR-129-5p. ConclusionsOverexpression of miR-129-5p protects against LPS-induced podocyte apoptosis, inflammation and AKI in vivo and in vitro models of sepsis. The underlying molecular mechanism is mediated via attenuating HMGB1/TLRs/NF-κB signaling axis modulated inflammatory response.

Downregulation of lncRNA ZFAS1 and upregulation of microRNA-129 repress endocrine disturbance, increase proliferation and inhibit apoptosis of ovarian granulosa cells in polycystic ovarian syndrome by downregulating HMGB1

ObjectiveThe objective was to find the role of long-non-coding RNA zinc finger antisense 1 (lncRNA ZFAS1)/microRNA (miR)-129/high-mobility group box protein 1 (HMGB1) axis in polycystic ovary syndrome (PCOS). MethodsOvarian granulosa cells from non-PCOS patients and PCOS patients were collected, and HMGB1, miR-129 and lncRNA ZFAS1 expression were detected. Ovarian granulosa cells were transfected with si-ZFAS1 or miR-129 mimics to verify their roles in P4 and E2 secretion, and the biological functions of ovarian granulosa cells. ResultsLncRNA ZFAS1 and HMGB1 were elevated, while miR-129 was down-regulated in ovarian granulosa cells of PCOS patients. Down-regulated lncRNA ZFAS1 or overexpressed miR-129 could decrease HMGB1 expression, increase P4 and E2 secretion, promote proliferation activity while inhibit apoptosis of ovarian granulosa cells in PCOS. ConclusionLncRNA ZFAS1 could bind to miR-129 to promote HMGB1 expression, thereby affecting the endocrine disturbance, proliferation and apoptosis of ovarian granulosa cells in PCOS.

Aberrant Expression of High Mobility Group Box Protein 1 in the Idiopathic Inflammatory Myopathies.

IntroductionHigh Mobility Group Box Protein 1 (HMGB1) is a DNA-binding protein that exerts inflammatory or pro-repair effects upon translocation from the nucleus. We postulate aberrant HMGB1 expression in immune-mediated necrotising myopathy (IMNM).MethodsHerein, we compare HMGB1 expression (serological and sarcoplasmic) in patients with IMNM with that of other myositis subtypes using immunohistochemistry and ELISA.ResultsIMNM (n = 62) and inclusion body myositis (IBM, n = 14) patients had increased sarcoplasmic HMGB1 compared with other myositis patients (n = 46). Sarcoplasmic HMGB1 expression correlated with muscle weakness and histological myonecrosis, inflammation, regeneration and autophagy. Serum HMGB1 levels were elevated in patients with IMNM, dermatomyositis and polymositis, and those myositis patients with extramuscular inflammatory features.DiscussionAberrant HMGB1 expression occurs in myositis patients and correlates with weakness. A unique expression profile of elevated sarcoplasmic and serum HMGB1 was detected in IMNM.

Using HMGB1 Protein as a Surrogate Marker for Lung Cancer in High‐Risk Populations

Lung cancer is the leading cause of cancer‐related death, independent of gender or ethnicity, with a 5‐year overall survival of 17.1%. Although screening protocols for early detection exist, lung cancer is often diagnosed at an advanced stage. This is due, in part, to many patients experiencing barriers to healthcare access which contribute to delays in diagnosis. Supra‐normal biosynthesis of saturated (SFA) and unsaturated fatty (UFA) acids is a hallmark of cancer. In fact, several lines of evidence demonstrate that increased lipid desaturation by stearoyl‐CoA desaturase (SCD1) promotes lung cancer growth. We hypothesize that increased intracellular UFA, such as oleate (OA), promotes cancer cell growth by reducing cancer associated inflammation. To test this hypothesis we evaluated the effect of OA and inhibition of OA synthesis on proinflammatory High Mobility Group Box Protein 1 (HMGB1). Decreasing OA synthesis reduced intracellular HMGB1 expression, but increased its release from cells. Given our data, alterations in OA levels appear to have a substantial effect on localization of HMGB1. Further work is necessary to define the connections between SCD1, OA and HMGB1 release in lung cancer cells. This knowledge will provide insight into how fat regulates cancer development.Support or Funding InformationThe University of Minnesota School of Medicine New Faculty Start up and College of Saint Scholastica McNair Scholars Program.

Role of HMGB1 in an Animal Model of Vascular Cognitive Impairment Induced by Chronic Cerebral Hypoperfusion.

The pathophysiology of vascular cognitive impairment (VCI) is associated with chronic cerebral hypoperfusion (CCH). Increased high-mobility group box protein 1 (HMGB1), a nonhistone protein involved in injury and inflammation, has been established in the acute phase of CCH. However, the role of HMGB1 in the chronic phase of CCH remains unclear. We developed a novel animal model of CCH with a modified bilateral common carotid artery occlusion (BCCAO) in C57BL/6 mice. Cerebral blood flow (CBF) reduction, the expression of HMGB1 and its proinflammatory cytokines (tumor necrosis factor-alpha [TNF-α], interleukin [IL]-1β, and IL-6), and brain pathology were assessed. Furthermore, we evaluated the effect of HMGB1 suppression through bilateral intrahippocampus injection with the CRISPR/Cas9 knockout plasmid. Three months after CCH induction, CBF decreased to 30–50% with significant cognitive decline in BCCAO mice. The 7T-aMRI showed hippocampal atrophy, but amyloid positron imaging tomography showed nonsignificant amyloid-beta accumulation. Increased levels of HMGB1, TNF-α, IL-1β, and IL-6 were observed 3 months after BCCAO. HMGB1 suppression with CRISPR/Cas9 knockout plasmid restored TNF-α, IL-1β, and IL-6 and attenuated hippocampal atrophy and cognitive decline. We believe that HMGB1 plays a pivotal role in CCH-induced VCI pathophysiology and can be a potential therapeutic target of VCI.

Upregulation of microRNA-204 improves insulin resistance of polycystic ovarian syndrome via inhibition of HMGB1 and the inactivation of the TLR4/NF-κB pathway

ABSTRACT There is growing evidence of the position of microRNAs (miRs) in polycystic ovarian syndrome (PCOS), thus our objective was to discuss the impact of miR-204 on insulin resistance (IR) in PCOS by targeting highmobility group box protein 1(HMGB1)-mediated toll-like receptor 4(TLR4)/nuclear factor-kappa B (NF-κB) pathway. PCOS-IR patients and PCOS non-insulin resistance (PCOS-NIR) patients were included. The levels of serum sex hormones and related insulin were measured, the expression of miR-204, HMGB1, TLR4 and NF-κB p65 was detected, the diagnostic efficacy of miR-204 in PCOS-IR was analyzed, and the correlation between the expression of miR-204 in PCOS-IR and fasting blood glucose (FPG), fasting insulin (FINS), homeostasis model of assessment for insulin resistance index (HOMA-IR) was analyzed. Both in vitro and in vivo experiments were performed to elucidate the capabilities of miR-204 and HMGB1 in proliferation and apoptosis of PCOS-IR granulosa cells. MiR-204 was lowly expressed as well as HMGB1, TLR4 and NF-κB p65 were highly expressed in PCOS-IR patients. Follicule-stimulating hormone was downregulated, while luteinizing hormone, estrogen, progesterone, FPG, FINS and HOMA-IR were elevated in PCOS-IR. Upregulation of miR-204 and downregulation of HMGB1 could repress TLR4/NF-κB pathway activation, degraded insulin release and testosterone (T) leveland ascended ovarian coefficient, boosted cell proliferation and restrained apoptosis of granulosa cells. Overexpression of HMGB1 reverses the effect of upregulation of miR-204 on IR of PCOS. Our study presents that high expression of miR-204 or inhibition of HMGB1 can improve IR of PCOS via the inactivation of TLR4/NF-κB pathway.

Expression of HMGB1 and TLR4 in neuropsychiatric systemic lupus erythematosus patients with seizure disorders.

Previous studies show that the high-mobility group box protein 1 (HMGB1) and the toll-like receptor 4 (TLR4) participate in systemic lupus erythematosus (SLE). The two molecules contribute to the occurrence and persistence of seizures in various disease conditions, such as epilepsy. Since seizures are one of the most severe complications associated with neuropsychiatric SLE (NPSLE), the current study aimed at investigating whether HMGB1 and TLR4 play any role in NPSLE related seizures. Data from 291 SLE patients and 100 healthy controls (HC) were prospectively collected from 2013 to 2018. The ELISA test was used to determine serum levels of HMGB1 for all patients and HC and cerebrospinal fluid (CSF) levels of NPSLE patients. The expression levels of TLR4 by the peripheral blood monocytes (PBMCs) were determined by real-time PCR of TLR4 mRNA. Binary logistic regression and ROC curve analysis were used to predict NPSLE. Among the 291 SLE patients, 188 had active disease and were grouped into two, NPSLE (N=86) and Non-NPSLE (N=102) groups. Among the NPSLE patients, 21 had seizure disorders. Serum HMGB1 levels were increased in NPSLE (8.73±0.29 ng/mL) and were associated with disease activity (r=0.6527, P=0.000). Both serum and CSF HMGB1 levels in NPSLE patients with seizure disorders (9.59±0.63 and 2.90±2.29 ng/mL, respectively) were higher than in patients with other neuropsychiatric symptoms (8.45±0.33 and 2.56±1.70 ng/mL, respectively), though without significance. The gene expression of mRNA TLR4 in PBMCs was similar to serum HMGB1 in the investigated groups. Independent predictors of NPSLE were SLEDAI-2k (OR 1.25; 95% CI: 1.155-1.353), serum HMGB1 (OR 1.659; 95% CI: 1.266-2.175), and anti-Rib-P Ab (OR 3.296; 95% CI: 1.013-10.725). ROC curves for the above predictors had a large AUC (95% CI) of 0.936 (0.900-0.971), indicating a good prediction of NPSLE occurrence. The expression of HMGB1 and TLR4 was increased in NPSLE, but HMGB1 and TLR4 had minimal effect on NPSLE related seizures. The serum levels of HMGB1 were positively correlated with disease activity, and could, therefore, be a potential biomarker of NPSLE for use in future clinical practice.

The activation of high mobility group Box1 and toll-like receptor 4 is involved in clopidogrel-induced gastric injury through p38 MAPK.

Clopidogrel-induced gastric injury is an important clinical problem. However, the exact mechanism was still unclarified. This study aimed to investigate the role of high mobility group box protein 1 (HMGB1) and the toll-like receptor 4 (TLR4) pathway in normal human gastric epithelial (GES-1) cells under clopidogrel exposure. Morphological alterations of the gastric epithelial cells were observed under a microscope. A laser scanning confocal microscope was used to determine the distribution of HMGB1 and TLR4 in clopidogrel-induced injury. MTT was used to compare the viability of GES-1 cell among the pretreated Cli-095 (TLR4 inhibitor) group, pretreated ethyl pyruvate (HMGB1 inhibitor) group, clopidogrel group, and control group. Moreover, expression of the HMGB1, TLR4, tight junction (TJ) proteins occludin and the phosphorylation of the mitogen-activated protein kinases (MAPK) p38 were examined by western blot. We found the expression of HMGB1 and TLR4 in the cytoplasm increased after clopidogrel administration. Besides, inhibited TLR4, which is a receptor of HMGB1, prevented the injury and occludin reducing caused by clopidogrel challenge. Furthermore, blocking HMGB1 or TLR4 activity by ethyl pyruvate (HMGB1 inhibitor) or cli-095(TLR4 inhibitor) can partially diminish the activation of p38MAPK. Gastric mucosal damages observed by clopidogrel challenge are associated with HMGB1, TLR4, through p38MAPK signal pathway.

High Mobility Group Box 1 Mediates TMAO-Induced Endothelial Dysfunction.

The intestinal microbe-derived metabolite trimethylamine N-oxide (TMAO) is implicated in the pathogenesis of cardiovascular diseases (CVDs). The molecular mechanisms of how TMAO induces atherosclerosis and CVDs’ progression are still unclear. In this regard, high-mobility group box protein 1 (HMGB1), an inflammatory mediator, has been reported to disrupt cell–cell junctions, resulting in vascular endothelial hyper permeability leading to endothelial dysfunction. The present study tested whether TMAO associated endothelial dysfunction results via HMGB1 activation. Biochemical and RT-PCR analysis showed that TMAO increased the HMGB1 expression in a dose-dependent manner in endothelial cells. However, prior treatment with glycyrrhizin, an HMGB1 binder, abolished the TMAO-induced HMGB1 production in endothelial cells. Furthermore, Western blot and immunofluorescent analysis showed significant decrease in the expression of cell–cell junction proteins ZO-2, Occludin, and VE-cadherin in TMAO treated endothelial cells compared with control cells. However, prior treatment with glycyrrhizin attenuated the TMAO-induced cell–cell junction proteins’ disruption. TMAO increased toll-like receptor 4 (TLR4) expression in endothelial cells. Inhibition of TLR4 expression by TLR4 siRNA protected the endothelial cells from TMAO associated tight junction protein disruption via HMGB1. In conclusion, our results demonstrate that HMGB1 is one of the important mediators of TMAO-induced endothelial dysfunction.