The Role of High-Mobility Group Box-1 and Its Crosstalk with Microbiome in Rheumatoid Arthritis

How does NFAT3 regulate the occurrence of cardiac hypertrophy?

Cardiac hypertrophy is initially an adaptive response to physiological and pathological stimuli. Although pathological myocardial hypertrophy is the main cause of morbidity and mortality, our understanding of its mechanism is still weak. NFAT3 (nuclear factor of activated T-cell-3) is a member of the nuclear factor of the activated T cells (NFAT) family. NFAT3 plays a critical role in regulating the expression of cardiac hypertrophy genes by inducing their transcription. Recently, accumulating evidence has indicated that NFAT3 is a potent regulator of the progression of cardiac hypertrophy. This review, for the first time, summarizes the current studies on NFAT3 in cardiac hypertrophy, including the pathophysiological processes and the underlying pathological mechanism, focusing on the nuclear translocation and transcriptional function of NFAT3. This review will provide deep insight into the pathogenesis of cardiac hypertrophy and a theoretical basis for identifying new therapeutic targets in the NFAT3 network.

Development of a biomarker panel for assessing cardiovascular risk in diabetic patients with chronic limb-threatening ischemia (CLTI): a prospective study

BACKGROUND

Lower-extremity endovascular revascularization (LER) is often required for diabetic patients with chronic limb threatening ischemia (CLTI). During the post-revascularization period patients may unpredictably experience major adverse cardiac events (MACE) and major adverse limb events (MALE). Several families of cytokines are involved in the inflammatory process that underlies the progression of atherosclerosis. According to current evidence, we have identified a panel of possible biomarkers related with the risk of developing MACE and MALE after LER. The aim was to study the relationship between a panel of biomarkers - Interleukin-1 (IL-1) and 6 (IL-6), C-Reactive Protein (CRP), Tumor Necrosis Factor-α (TNF-α), High-Mobility Group Box-1 (HMGB-1), Osteoprotegerin (OPG), Sortilin and Omentin-1- at baseline, with cardiovascular outcomes (MACE and MALE) after LER in diabetic patients with CLTI.

METHODS

In this prospective non-randomized study, 264 diabetic patients with CLTI undergoing endovascular revascularization were enrolled. Serum levels of each biomarker were collected before revascularization and outcomes' incidence was evaluated after 1, 3, 6 and 12 months.

RESULTS

During the follow-up period, 42 cases of MACE and 81 cases of MALE occurred. There was a linear association for each biomarker at baseline and incident MACE and MALE, except Omentin-1 levels that were inversely related to the presence of MACE or MALE. After adjusting for traditional cardiovascular risk factors, the association between each biomarker baseline level and outcomes remained significant in multivariable analysis. Receiver operating characteristics (ROC) models were constructed using traditional clinical and laboratory risk factors and the inclusion of biomarkers significantly improved the prediction of incident events.

CONCLUSIONS

Elevated IL-1, IL-6, CRP, TNF-α, HMGB-1, OPG and Sortilin levels and low Omentin-1 levels at baseline correlate with worse vascular outcomes in diabetic patients with CLTI undergoing LER. Assessment of the inflammatory state with this panel of biomarkers may support physicians to identify a subset of patients more susceptible to the procedure failure and to develop cardiovascular adverse events after LER.

Psoriatic arthritis: review of potential biomarkers predicting response to TNF inhibitors

Psoriatic arthritis (PsA) is a chronic and painful inflammatory immune-mediated disease. It affects up to 40% of people with psoriasis and it is associated with several comorbidities such as obesity, diabetes, metabolic syndrome, and hypertension. PsA is difficult to diagnose because of its diverse symptoms, namely axial and peripheral arthritis, enthesitis, dactylitis, skin changes, and nail dystrophy. Different drugs exist to treat the inflammation and pain. When patients do not respond to conventional drugs, they are treated with biologic drugs. Tumour necrosis factor inhibitors (TNFi's) are commonly given as the first biologic drug; beside being expensive, they also lack efficacy in 50% of patients. A biomarker predicting individual patient's response to TNFi would help treating them earlier with an appropriate biologic drug. This study aimed to review the literature to identify potential biomarkers that should be investigated for their predictive ability. Several such biomarkers were identified, namely transmembrane TNFα (tmTNF), human serum albumin (HSA) and its half-life receptor, the neonatal Fc receptor (FcRn) which is also involved in IgG lifespan; calprotectin, high mobility group protein B1 (HMGB1) and advanced glycation end products (AGEs) whose overexpression lead to excessive production of pro-inflammatory cytokines; lymphotoxin α (LTα) which induces inflammation by binding to TNF receptor (TNFR); and T helper 17 (Th17) cells which induce inflammation by IL-17A secretion.

Subchronic Oral Cylindrospermopsin Exposure Alters the Host Gut Microbiome and Is Associated with Progressive Hepatic Inflammation, Stellate Cell Activation, and Mild Fibrosis in a Preclinical Study

Epidemiological studies have reported a strong association between liver injury and incidences of hepatocellular carcinoma in sections of humans globally. Several preclinical studies have shown a strong link between cyanotoxin exposure and the development of nonalcoholic steatohepatitis, a precursor of hepatocellular carcinoma. Among the emerging threats from cyanotoxins, new evidence shows cylindrospermopsin release in freshwater lakes. A known hepatotoxin in higher concentrations, we examined the possible role of cylindrospermopsin in causing host gut dysbiosis and its association with liver pathology in a mouse model of toxico-pharmacokinetics and hepatic pathology. The results showed that oral exposure to cylindrospermopsin caused decreased diversity of gut bacteria phyla accompanied by an increased abundance of Clostridioides difficile and decreased abundance of probiotic flora such as Roseburia, Akkermanssia, and Bacteroides thetaiotamicron, a signature most often associated with intestinal and hepatic pathology and underlying gastrointestinal disease. The altered gut dysbiosis was also associated with increased Claudin2 protein in the intestinal lumen, a marker of gut leaching and endotoxemia. The study of liver pathology showed marked liver inflammation, the release of damage-associated molecular patterns, and activation of toll-like receptors, a hallmark of consistent and progressive liver damage. Hepatic pathology was also linked to increased Kupffer cell activation and stellate cell activation, markers of progressive liver damage often linked to the development of liver fibrosis and carcinoma. In conclusion, the present study provides additional evidence of cylindrospermopsin-linked progressive liver pathology that may be very well-linked to gut dysbiosis, though definitive evidence involving this link needs to be studied further.

Targeted inhibition of GRK2 kinase domain by CP-25 to reverse fibroblast-like synoviocytes dysfunction and improve collagen-induced arthritis in rats

Rheumatoid arthritis (RA) is an autoimmune disease and is mainly characterized by abnormal proliferation of fibroblast-like synoviocytes (FLS). The up-regulated cellular membrane expression of G protein coupled receptor kinase 2 (GRK2) of FLS plays a critical role in RA progression, the increase of GRK2 translocation activity promotes dysfunctional prostaglandin E4 receptor (EP4) signaling and FLS abnormal proliferation. Recently, although our group found that paeoniflorin-6ʹ-O-benzene sulfonate (CP-25), a novel compound, could reverse FLS dysfunction via GRK2, little is known as to how GRK2 translocation activity is suppressed. Our findings revealed that GRK2 expression up-regulated and EP4 expression down-regulated in synovial tissues of RA patients and collagen-induced arthritis (CIA) rats, and prostaglandin E2 (PGE2) level increased in arthritis. CP-25 could down-regulate GRK2 expression, up-regulate EP4 expression, and improve synovitis of CIA rats. CP-25 and GRK2 inhibitors (paroxetine or GSK180736A) inhibited the abnormal proliferation of FLS in RA patients and CIA rats by down-regulating GRK2 translocation to EP4 receptor. The results of microscale thermophoresis (MST), cellular thermal shift assay, and inhibition of kinase activity assay indicated that CP-25 could directly target GRK2, increase the protein stability of GRK2 in cells, and inhibit GRK2 kinase activity. The docking of CP-25 and GRK2 suggested that the kinase domain of GRK2 might be an important active pocket for CP-25. G201, K220, K230, A321, and D335 in kinase domain of GRK2 might form hydrogen bonds with CP-25. Site-directed mutagenesis and co-immunoprecipitation assay further revealed that CP-25 down-regulated the interaction of GRK2 and EP4 via controlling the key amino acid residue of Ala321 of GRK2. Our data demonstrate that FLS proliferation is regulated by GRK2 translocation to EP4. Targeted inhibition of GRK2 kinase domain by CP-25 improves FLS function and represents an innovative drug for the treatment of RA by targeting GRK2.

HMGB1-RAGE-moesin axis may be indicted for acne vulgaris

BACKGROUND

High-mobility group box 1 (HMGB1)-receptor for advanced glycation end (RAGE)-moesin axis could be implicated in induction of inflammation. However, there is a scarcity in literature discussing the role of this axis in inflammatory skin disorders.

AIMS

The aim of the present study was to evaluate the serum levels of HMGB1 and moesin in patients with inflammatory acne vulgaris.

PATIENTS/METHODS

This comparative cross-sectional study included 66 inflammatory acne vulgaris patients classified according to Global Acne Grading System (GAGS) into three groups (22 patients each): mild, moderate, and severe acne vulgaris. In addition, 82 acne-free individuals were included as a control group. Serum HMGB 1 and moesin levels were measured using enzyme-linked immunosorbent assay kits.

RESULTS

High-mobility group box 1 and moe sin serum levels in acne patients were significantly higher than the levels in control subjects (p = 0.04, 0.0005 respectively). Serum levels of both markers in severe acne patients and in those with post-acne scarring were elevated when compared to the levels in the other groups, and however, this elevation was significant only for moesin levels. There was a significant positive correlation between the serum levels of HMGB1 and moesin in the studied patient's sample (r = 0.3079, p = 0.011).

CONCLUSION

High-mobility group box 1-receptor for advanced glycation end-moesin axis may be implicated in acne vulgaris pathogenesis, and it may be a promising therapeutic target.

Recombinant high‑mobility group box 1 induces cardiomyocyte hypertrophy by regulating the 14‑3‑3η, PI3K and nuclear factor of activated T cells signaling pathways

High-mobility group box 1 (HMGB1) is released by necrotic cells and serves an important role in cardiovascular pathology. However, the effects of HMGB1 in cardiomyocyte hypertrophy remain unclear. Therefore, the aim of the present study was to investigate the potential role of HMGB1 in cardiomyocyte hypertrophy and the underlying mechanisms of its action. Neonatal mouse cardiomyocytes (NMCs) were co-cultured with recombinant HMGB1 (rHMGB1). Wortmannin was used to inhibit PI3K activity in cardiomyocytes. Subsequently, atrial natriuretic peptide (ANP), 14-3-3 and phosphorylated-Akt (p-Akt) protein levels were detected using western blot analysis. In addition, nuclear factor of activated T cells 3 (NFAT3) protein levels were measured by western blot analysis and observed in NMCs under a confocal microscope. The results revealed that rHMGB1 increased ANP and p-Akt, and decreased 14-3-3η protein levels. Furthermore, wortmannin abrogated the effects of rHMGB1 on ANP, 14-3-3η and p-Akt protein levels. In addition, rHMGB1 induced nuclear translocation of NFAT3, which was also inhibited by wortmannin pretreatment. The results of this study suggest that rHMGB1 induces cardiac hypertrophy by regulating the 14-3-3η/PI3K/Akt/NFAT3 signaling pathway.

MicroRNA-410-3p modulates chondrocyte apoptosis and inflammation by targeting high mobility group box 1 (HMGB1) in an osteoarthritis mouse model

Background

Osteoarthritis (OA) is the most prevalent type of arthritis, which commonly involves inflammation in the articular cartilage in OA pathogenesis. MicroRNAs (miRNAs) play essential roles in the regulation and pathophysiology of various diseases including OA. MiR-410-3p has been demonstrated to mediate inflammatory pathways, however, the regulatory functions of miR-410-3p in OA remain largely unknown.

Methods

The regulations of miR-410-3p were investigated in OA. Mouse primary chondrocytes and mouse in vivo models were used. The expression levels of miR-410-3p and HMGB1 were measured by qPCR. The transcription activity of NF-κB was assessed by luciferase reporter assay. MTT assay was performed to assess cellular proliferation. Cell apoptosis was evaluated with the Fluorescein Isothiocyanate (FITC) Annexin V assay. Expression levels of proteins were determined by Western blot.

Results

The results demonstrated that miR-410-3p was markedly downregulated in articular cartilage tissues as well as in lipopolysaccharide (LPS)-treated chondrocytes in OA mice. In addition, upregulation of miR-410-3p markedly inhibited LPS-induced apoptosis of chondrocytes. The results also demonstrated that the high mobility group box 1 (HMGB1) was a target of miR-410-3p. LPS-induced upregulated expression of HMGB1 significantly suppressed expression of miR-410-3p. Furthermore, upregulation of miR-410-3p markedly inhibited HMGB1 expression, the nuclear factor (NF)-kB activity and pro-inflammatory cytokines production. Taken together, the results suggested that miR-410-3p targeted HMGB1 and modulated chondrocytes apoptosis and inflammation through the NF-κB signaling pathway.

Conclusions

These findings provide insights into the potential of miR-410-3p/ HMGB1 as therapeutic targets for OA treatment.

Increased serum calpain activity is associated with HMGB1 levels in systemic sclerosis

Background

Systemic sclerosis (SSc) or scleroderma is an intractable autoimmune disorder that affects multiple organs. The objectives were to investigate clinical correlations of serum calpain activity and high mobility group box 1 (HMGB1) levels with immunological and clinical traits.

Methods

A total of 31 patients with SSc, 20 age- and gender-matched healthy control subjects (HC), and 10 patients with other connective tissue diseases (CTD) were recruited in the study. We measured serum calpain activity and HMGB1 levels and analyzed the datasets (GSE40839, GSE48149, GSE76808, GSE81292, GSE33463, and GSE58095) from Gene Expression Omnibus (GEO) database to explore the potential mechanism by which calpain exerts its function through bioinformatics methods.

Results

Serum calpain activity was significantly increased in patients with SSc compared with those in HC and in patients with CTD and was correlated with serum HMGB1 levels, modified Rodnan skin score, erythrocyte sedimentation rate, mean platelet volume, and plateletcrit. Notably, serum calpain activity and HMGB1 levels in SSc patients with interstitial lung disease (ILD) were significantly higher than those in SSc patients without ILD. Serum calpain activity and HMGB1 levels could be the independent risk factors for SSc-ILD and novel biomarkers in patients with SSc.

Conclusion

This is the first study that reports increased serum calpain activity and the correlation between calpain and HMGB1 in patients with SSc or SSc-ILD. The serum calpain activity and HMGB1 levels may serve as measures of ILD in patients with SSc. Also, calpain and HMGB1 could be potential therapeutic targets for patients with SSc or SSc-ILD in the future.

Biomarkers of vascular disease in diabetes: the adipose-immune system cross talk

Experimental and clinical studies aimed at investigating the mechanism(s) underlying vascular complications of diabetes indicate that a great number of molecules are involved in the pathogenesis of these complications. Most of these molecules are inflammatory mediators or markers generated by immune or adipose tissue. Some of them, i.e. resistin and sortilin, have been shown to be involved in the cross talk between adipocytes and inflammatory cells. This interaction is an attractive area of research, particularly in type 2 diabetes and obesity. Other proteins, such as adiponectin and visfatin, appear to be more promising as possible vascular markers. In addition, some molecules involved in calcium/phosphorus metabolism, such as klotho and FGF23, have an involvement in the pathogenesis of diabetic vasculopathy, which appears to be dependent on the degree of vascular impairment. Inflammatory markers are a promising tool for treatment decisions while measuring plasma levels of adipokines, sortilin, Klotho and FGF23 in adequately sized longitudinal studies is expected to allow a more precise characterization of diabetic vascular disease and the optimal use of personalized treatment strategies.

High Mobility Group Box-1 and Diabetes Mellitus Complications: State of the Art and Future Perspectives

Diabetes mellitus (DM) is an endemic disease, with growing health and social costs. The complications of diabetes can affect potentially all parts of the human body, from the heart to the kidneys, peripheral and central nervous system, and the vascular bed. Although many mechanisms have been studied, not all players responsible for these complications have been defined yet. High Mobility Group Box-1 (HMGB1) is a non-histone nuclear protein that has been implicated in many pathological processes, from sepsis to ischemia. The purpose of this review is to take stock of all the most recent data available on the role of HMGB1 in the complications of DM.

HMGB1 was negatively regulated by HSF1 and mediated the TLR4/MyD88/NF-κB signal pathway in asthma

AIMS

The present study explored the function and regulatory mechanism of High mobility group box 1 (HMGB1) in asthma.

MAIN METHODS

OVA (ovalbumin)-induced asthmatic mice model and LPS-treated cellular model were established in this study. Airway inflammation was measured through detecting the expression of IL-4, IL-5, IL-13 and Interferon-γ (IFN-γ) in serum and BALF (bronchoalveolar lavage fluid) by ELISA kits. Bioinformatics predictive analysis, ChIP assays, Luciferase reporter assay and Western blotting were used to explore the relation between HMGB1 and HSF1 (Heat shock factor 1).

KEY FINDINGS

HMGB1 expression was increased in OVA-induced asthmatic mice. Silencing HMGB1 attenuated the increasing of IgE, inflammatory factors (IL-4, IL-5 and IL-13), and airway hyperresponsiveness that induced by OVA. In addition, our study found that HSF1 directly bind with the HMGB1 promoter and negatively regulation of HMGB1. HSF-1 were upregulated in OVA-induced asthmatic mice, and knockdown of HSF1 aggravated the OVA-induced airway inflammation and airway hyperreactivity in mice may through promoting the expression of HMGB1 and the activation of the Toll-like receptor 4 (TLR4)/Myeloid differentiation primary response 88 (MyD88)/Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signal pathway.

SIGNIFICANCE

The expression of HMGB1 could be negatively regulated by HSF1, and the TLR4/MyD88/NF-κB signal pathway was involved in HSF1/HMGB1-mediated regulation of asthma.

The Role of the Microbiota in the Diabetic Peripheral Artery Disease

Vascular complications of diabetes mellitus represent a major public health problem. Although many steps forward have been made to define the causes and to find the best possible therapies, the problem remains crucial. In recent years, more and more evidences have defined a link between microbiota and the initiation, promotion, and evolution of atherosclerotic disease, even in the diabetic scenario. There is an urgency to develop the knowledge of modern medicine about the link between gut microbiota and its host's metabolic pathways, and it would be useful to understand and justify the interindividual diversity of clinical disease presentation of diabetic vascular complication even if an optimization of pharmacological treatment has been made or in the case of young patients where hypertension, dyslipidemia, and diabetes are not able to justify a very quick progress of atherosclerotic process. The aim of the present review is to gather all the best available evidence in this regard and to define a new role of the microbiota in this field, from biomarker to possible therapeutic target.