Redox-active trace metal-induced release of high mobility group box 1(HMGB1) and inflammatory cytokines in fibroblast-like synovial cells is Toll-like receptor 4 (TLR4) dependent

Atractylenolide-III attenuates osteoarthritis by repolarizing macrophages through inactivating TLR4/NF-κB signaling

BACKGROUND

As a common chronic musculoskeletal condition, osteoarthritis (OA) presently lacks particular treatment strategies. The aim of this study was to examine how AT-III therapies affected macrophage repolarity in order to slow down the advancement of OA.

METHODS

RAW264.7 macrophages were polarized to M1 subtypes then administered with different concentrations of AT-III. Immunofluorescence, qRT-PCR and flow cytometry were used to assess the polarization of the macrophages. The mechanism of AT-III repolarize macrophages was evaluated by western blot. Furthermore, the effects of macrophage conditioned media (CM) on the migration, proliferation, and chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) were investigated using CCK-8 assays, the scratch test, and alcian blue staining. The effects of macrophage CM on chondrocyte proliferation and degeneration were investigated using CCK-8 and qRT-PCR. In vivo micro-CT and histological observations were performed on rats with anterior cruciate ligament transection and partial medial meniscectomy, either with or without AT-III treatment.

RESULTS

AT-III repolarized M1 macrophages to M2 phenotype. Mechanistically, AT-III reduced the expression of Toll-like receptor(TLR) 4 induced by lipopolysaccharide in RAW264.7 and lowered nuclear factor-κB (NF-κB) signaling molecules p-p65 and p-IκBα. The TLR4 agonist RS09 reversed the effects of AT-III on macrophage repolarization. AT-III-induced macrophages CM stimulated BMSCs migration, proliferation and chondrogenic differentiation. AT-III-treated macrophage CM promoted chondrocyte proliferation while inhibiting chondrocyte degeneration. In vivo, AT-III treatment alleviated the degree of synovitis, inhibited subchondral bone remodeling and reduced cartilage destruction in the rat OA model.

CONCLUSIONS

AT-III attenuates OA by repolarizing macrophages through inactivating TLR4/NF-κB signaling. These data suggest that AT-III may be an effective therapeutic candidate for OA treatment.

Correlation of Delayed Onset Muscle Soreness and Inflammation Post-exercise Induced Muscle Damage

BACKGROUND: Delayed Onset Muscle Soreness (DOMS) is a common injury resulting from abnormal intensive training in athletes, mainly the result of training involving eccentric contractions. AIM: The aim of this study was to determine the correlation between the incidence of DOMS and HMGB1 as a marker of the occurrence of inflammation post Exercise Induces Muscle Damaged. METHOD: 28 male recreational students of Sports Science Department, Universitas Negeri Surabaya who met all inclusion and exclusion criteria participated in this study. Participants completed a muscle damaging exercise which consists of a 10x10 drop jump (DRP) and a bout of 40×15 m sprints with a 5 m deceleration zone (SPR) to obtain a muscle damage effect. In this study, the stretching in the exercise session was not given, this was done to get the DOMS effect after exercise. DOMS and HMGB1 was carry out 1 hour before the exercise, 12 hours after the exercise, 24 hours after the exercise and 48 hours after the exercise. RESULT: The result showed that there was a significant correlation (r=0.935, p<0.05) between DOMS and HMGB1 as a predictor of inflammation. The participants that were given EIMD eccentric exercise (DRP and SPR) showed the occurrence of DOMS and increasing of HMGB1. The result also showed that there was a correlation between DOMS and HMGB1. CONCLUSION: This study concluded that there was a correlation between DOMS and HMGB1 as a marker of inflammation as the result of the eccentric exercise of the exercise Induced Muscle Damage (EIMD).

High-mobility group box 1 (HMGB1) in COVID-19: extrapolation of dangerous liaisons

High-mobility group box 1 (HMGB1), a multifunctional nuclear protein, exists mainly within the nucleus of all mammal eukaryotic cells. It is actively secreted by the necrotic cells as a response to the inflammatory signaling pathway. HMGB1 binds to receptor ligands as RAGE, and TLR and becomes a pro-inflammatory cytokine with a robust capacity to trigger inflammatory response. It is a critical mediator of the pathogenesis of systemic inflammation in numerous inflammatory disorders. Release of HMGB1 is associated with different viral infections and strongly participates in the regulation of viral replication cycles. In COVID-19 era, high HMGB1 serum levels were observed in COVID-19 patients and linked with the disease severity, development of cytokine storm (CS), acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). SARS-CoV-2-induced cytolytic effect may encourage release of HMGB1 due to nuclear damage. Besides, HMGB1 activates release of pro-inflammatory cytokines from immune cells and up-regulation of angiotensin I-converting enzyme 2 (ACE2). Therefore, targeting of the HMGB1 pathway by anti-HMGB1 agents, such as heparin, resveratrol and metformin, may decrease COVID-19 severity. HMGB1 signaling pathway has noteworthy role in the pathogenesis of SARS-CoV-2 infections and linked with development of ALI and ARDS in COVID-19 patients. Different endogenous and exogenous agents may affect release and activation of HMGB1 pathway. Targeting of HMGB1-mediated TLR2/TLR4, RAGE and MAPK signaling, might be a new promising drug candidate against development of ALI and/or ARDS in severely affected COVID-19 patients.

Subacute cadmium exposure promotes M1 macrophage polarization through oxidative stress-evoked inflammatory response and induces porcine adrenal fibrosis

Cadmium (Cd) is a widely distributed environmental pollutant with immunotoxicity and endocrine toxicity. M1/M2 macrophages participate in the immune response and exert an essential influence on fibrosis. Nevertheless, whether Cd can induce porcineadrenal fibrosis by affecting the polarization of M1/M2 macrophages and its potential regulatory mechanism have not been explored. We added 20 mg/kg CdCl₂ to the pig diet for 40 days to investigate the fibrogenic effect of subacute Cd exposure on the adrenal gland. The results indicated that the ACTH and CORT in serum were decreased by 15.26 % and 21.99 %, respectively. The contents of adrenal mineral elements Cd, Cr, Mn were increased up to 34, 1.93, 1.42 folds and Co, Zn, Sn were reduced by 21.57 %, 20.52 %, 15.75 %. Concurrently, the pro-oxidative indicators (LPO, MDA and H₂O₂) were increased by 1.85, 2.20, 2.77 folds and 3.60, 11.15, 4.11 folds upregulated mRNA levels of TLR4, NF-κB, NLRP3 were observed. Subsequently, the expression of M1 macrophages polarization markers (IL-6, iNOS, TNF-α, CCL2 and CXCL9) were raised by 2.03, 2.30, 2.35, 1.58, 1.56 folds, while M2 macrophages (IL-4, CCL24, Arg1, IL-10, MRC1) showed a 62.34 %, 31.88 %, 50.26 %, 74.00 %, 69.34 % downregulation. The expression levels of AMPK subunits and genes related to glycolysis, oxidative phosphorylation (OXPHOS) and fatty acid oxidation (FAO) were also markedly increased. Additionally, the expression level of TGF-β1, Smad2/3 and downstream pro-fibrotic markers was obviously upregulated. Taken together, we conclude that Cd activates the oxidative stress-mediated TLR4/NF-κB/NLRP3 inflammatory signal transduction, leading to porcine adrenal fibrosis by promoting macrophage polarization toward M1.

[Mechanism of high expression of high mobility group protein 1 in a rat model of knee osteoarthritis]

OBJECTIVE

To investigate the molecular mechanism triggering pyroptosis of synovial fibroblast-like synoviocytes(FLSs)and the release of high mobility group protein 1(HMGB1)in a rat model of knee osteoarthritis(KOA).

METHODS

Twelve SD rats were randomized equally into blank control group without any treatment and KOA group with anterior cruciate ligament amputation (ACLT) to induce KOA.HE staining and Mankin score were used to evaluate the damage of knee cartilage.Western blotting was used to detect the expression of pyroptosis-related proteins and HMGB1 in the synovial tissue.In the cell experiment, rat FLSs were treated with PBS (control group), LPS+ATP (to induce cell pyroptosis), or LPS+ATP+siRNAs (to inhibit pyroptosis of the FLSs), and the cellular expressions of apoptosis-related proteins and HMGB1 were detected using Western blotting; the level of HMGB1 in the culture supernatant was detected with ELISA.

RESULTS

In the rat models of KOA, the expressions of pyroptosis-related proteins and HMGB1 in the synovial tissue and Mankin score were significantly increased as compared with those in the control group(P < 0.05).In cultured rat FLSs, the expressions of apoptosis related proteins and HMGB1 were significantly higher in the pyroptosis group than in the control group and in cells transfected with the siRNAs targeting NLRP1, NLRP3, ASC and caspase-1(P < 0.05).The protein level of HMGB1 in the culture supernatant was significantly higher in pyroptosis group than in the control and siRNA groups (P < 0.05).

CONCLUSION

In the pathological process of KOA, NLRPs inflammasome-mediated FLS pyroptosis causes massive release of HMGB1, which is associated with the activation of the downstream molecule caspase-1.

TLRs Play Crucial Roles in Regulating RA Synoviocyte

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease comparing the inflammation of synovium. Macrophage-like synoviocytes and fibroblast-like synoviocytes (synoviocytes) are crucial ingredients of synovium. Therein, a lot of research has focused on synoviocytes. Researches demonstrated that TLR1, TLR2, TLR3, TLR4, TLR5, TLR6 TLR7 and TLR9 are expressed in synoviocyte. Additionally, the expression of TLR2, TLR3, TLR4 and TLR5 is increased in RA synoviocyte. In this paper, we review the exact role of TLR2, TLR3, TLR4 and TLR5 participate in regulating the production of inflammatory factors in RA synoviocyte. Furthermore, we discuss the role of vasoactive intestinal peptide (VIP), MicroRNA, Monome of Chinese herb and other cells (Monocyte and T cell) influence the function of synoviocyte by regulating TLRs. The activation of toll-like receptors (TLRs) in synoviocyte leads to the aggravation of arthritis, comparing with angiogenesis and bone destruction. Above all, TLRs are promising targets for managing RA.

Correlation between Metal Ions and Cytokines in the Saliva of Patients with Oral Lichenoid Lesions

PURPOSE

We aimed to investigate the effect of metal ions from oral prostheses (OPs) released into the saliva of patients with oral lichenoid lesions (OLLs).

MATERIALS AND METHODS

Subjects (n=183) were divided into four groups according to the presence or absence of OLL and OP. Concentrations of the metal ions titanium, chromium (Cr), cobalt (Co), nickel (Ni), palladium (Pd), silver (Ag), platinum (Pt), gold (Au), and zirconium (Zr) were measured using a laser-ablation microprobe inductively coupled to a plasma mass spectrometer. Saliva levels of interleukin (IL)-6, IL-1β, IL-8, and tumor necrosis factor-α were detected using an enzyme-linked immunosorbent assay. The reticulation/keratosis, erythema, and ulceration (REU) scoring system was used to assess the severity of OLL.

RESULTS

Mean concentrations of IL-6 and IL-8 were statistically higher in OLL patients with OPs. The concentration of Ni was high in OLL groups. The concentrations of Cr, Ni, and Au ions in the saliva were positively correlated with IL-8. REU scores were positively correlated with salivary concentrations of IL-6 and IL-8, as well as with concentrations of Cr, Ni, and Au.

CONCLUSION

Increased concentrations of metal ions, especially Ni, in saliva were positively correlated with IL-8 and showed positive correlations with the severity of OLL.

Role of HMGB1 in Chemotherapy-Induced Peripheral Neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN), one of major dose-limiting side effects of first-line chemotherapeutic agents such as paclitaxel, oxaliplatin, vincristine, and bortezomib is resistant to most of existing medicines. The molecular mechanisms of CIPN have not been fully understood. High mobility group box 1 (HMGB1), a nuclear protein, is a damage-associated molecular pattern protein now considered to function as a pro-nociceptive mediator once released to the extracellular space. Most interestingly, HMGB1 plays a key role in the development of CIPN. Soluble thrombomodulin (TMα), known to degrade HMGB1 in a thrombin-dependent manner, prevents CIPN in rodents treated with paclitaxel, oxaliplatin, or vincristine and in patients with colorectal cancer undergoing oxaliplatin-based chemotherapy. In this review, we describe the role of HMGB1 and its upstream/downstream mechanisms in the development of CIPN and show drug candidates that inhibit the HMGB1 pathway, possibly useful for prevention of CIPN.

Expression of Toll-Like Receptors in the Animal Model of Bladder Outlet Obstruction

Introduction

Bladder outlet obstruction (BOO) occurs in more than 20 percent of the adult population and may lead to changes in the structure and function of the bladder. The main objective of the study was to evaluate the expression of Toll-like receptor 4 (TLR 4) and Toll-like receptor 9 (TLR 9) in the animal model of BOO as potential triggers of the inflammation phase in the bladder. In addition, the modulating effect of alpha-1 adrenergic antagonist (tamsulosin) on TLR 4 and TLR 9 expression and inflammatory markers was assessed. Material and Methods. Thirty-two male, 9-week-old Sprague Dawley rats were randomly divided into 4 groups: SOP—sham-operated rats with a placebo (water); SOB—sham-operated rats with an alpha-1 adrenergic antagonist; BOOP—rats with BOO and a placebo; and BOOB—rats with BOO and an alpha-1 adrenergic antagonist. The rats were given a placebo or alpha-1 adrenergic antagonist for 15 days. Next, urine and the bladder were collected from the rats for histopathological and biochemical study.

Results

Histopathological analysis showed chronic inflammation without acute inflammation in the bladder. TLR 4 showed positive cytoplasmic reactivity in the urothelium and the smooth muscles of the bladder. TLR 9 showed positive cytoplasmic reactivity only in the urothelium. BOO caused an increase in TLR 4 and TLR 9 expression. Furthermore, treatment with an alpha-1 adrenergic antagonist had no significant effect on TLR 4 and TLR 9 expression in rats with BOO. BOO caused a significant increase in urine concentration of interleukin 6 (IL-6), while alpha-1 antagonist reduced the urine concentration of IL-6 and the concentration of interleukin 18 (IL-18).

Conclusions

The results suggest the participation of TLR 4 and TLR 9 receptors in the induction of inflammation in the bladder, which is the first phase in the development of pathophysiological changes in BOO.

Relationship between the pyroptosis of fibroblast‑like synoviocytes and HMGB1 secretion in knee osteoarthritis

High mobility group box 1 (HMGB1) is an important downstream product of pyroptosis in macrophages, and it serves a vital role in numerous inflammatory diseases. Previous studies have reported that HMGB1 is released by fibroblast-like synoviocytes (FLSs) that are activated by inflammatory cytokines in knee osteoarthritis (KOA); however, the mechanism via which FLS promotes HMGB1 secretion in KOA remains unknown. According to our previous study, pyroptosis occurs in FLSs of patients with KOA and is mediated by Nod-like receptor protein (NLRP)1 or NLRP3 inflammasomes. However, the specific relationship between HMGB1 secretion and FLS pyroptosis requires further investigation. In the present study, the association between HMGB1 secretion and FLS pyroptosis was investigated in vitro and in vivo. In this study, western blotting, ELISA and reverse transcription-quantitative PCR were used to measure expression levels of proteins and mRNA. Caspase-1 activity assay and Hoechst 33342/PI double staining were used to observe the pyroptosis of FLSs. Hematoxylin and eosin staining was used to observe the destruction of cartilage in KOA. Increased expression levels of pyroptosis-related proteins and HMGB1 in the synovium of rat anterior cruciate ligament transection-induced KOA models were identified, and these changes were significantly mitigated via the intra-articular injection of a caspase-1 inhibitor. In vitro, FLSs were treated with lipopolysaccharide (LPS) + ATP to induce pyroptosis, and HMGB1 secretion was subsequently measured. LPS + ATP significantly increased the expression levels of pyroptosis-related proteins and HMGB1 in FLSs, and these effects were significantly mitigated by small interfering RNAs targeting NLRP1, NLRP3, apoptosis-associated speck-like protein with a caspase-recruitment domain or caspase-1. Therefore, the present results indicated that NLRP1/NLRP3 inflammasome-mediated and caspase-1-dependent FLS pyroptosis increased HMGB1 secretion in KOA. These findings may provide a therapeutic strategy to decrease synovial inflammatory responses during KOA progression.

Copper and cadmium administration induce toxicity and oxidative stress in the marine flatworm Macrostomum lignano

The contamination of coastal regions with different toxicants, including heavy metal ions such as copper and cadmium jeopardize health and survival of organisms exposed to this habitat. To study the effects of high copper and cadmium concentrations in these marine environments, we used the flatworm Macrostomum lignano as a model. This platyhelminth lives in shallow coastal water and is exposed to high concentrations of all toxicants that accumulate in these sea floors. We could show that both, cadmium and copper show toxicity at higher concentrations, with copper being more toxic than cadmium. At concentrations below acute toxicity, a reduced long-term survival was observed for both metal ions. The effects of sublethal doses comprise reduced physical activities, an increase in ROS levels within the worms, and alterations of the mitochondrial biology. Moreover, cell death events were substantially increased in response to sublethal concentrations of both metal ions and stem cell activity was reduced following exposure to higher cadmium concentrations. Finally, the expression of several genes involved in xenobiotic metabolism was substantially altered by this intervention. Taken together, M. lignano has been identified as a suitable model for marine toxicological studies as it allows to quantify several relevant life-history traits as well as of physiological and behavioral read-outs.

Efficacy and safety of NI-0101, an anti-toll-like receptor 4 monoclonal antibody, in patients with rheumatoid arthritis after inadequate response to methotrexate: a phase II study

OBJECTIVES

Anti-citrullinated protein antibodies (ACPAs) form immune complexes with citrullinated proteins binding toll-like receptor (TLR) 4, which has been proposed as a mediator of rheumatoid arthritis (RA). NI-0101 is a first-in-class humanised monoclonal antibody blocking TLR4, as confirmed by inhibition of in vivo lipopolysaccharide-induced cytokine release in healthy volunteers. This study was design to confirm preclinical investigations supporting a biomarker-driven approach for treatment of patients with RA who present positive for these immune complexes.

METHODS

Placebo-controlled, double-blind, randomised (2:1) trial of the tolerability and efficacy of NI-0101 (5 mg/kg, every 2 weeks for 12 weeks) versus placebo in ACPA-positive RA patients with inadequate response to methotrexate. Efficacy measures included Disease Activity Score (28-joint count) with C reactive protein (DAS28-CRP), European League Against Rheumatism (EULAR) good and moderate responses, and American College of Rheumatology (ACR) 20, ACR50 and ACR70 responses. Subgroup analyses defined on biomarkers were conducted. Pharmacokinetics, pharmacodynamics and safety were reported.

RESULTS

90 patients were randomised (NI-0101 (61) and placebo (29)); 86 completed the study. No significant between-group difference was observed for any of the efficacy endpoints. Subgroup analyses using baseline parameters as covariants did not reveal any population responding to NI-0101. Treatment-emergent adverse events occurred in 51.7% of patients who received placebo versus 52.5% for NI-0101.

CONCLUSIONS

We demonstrate for the first time that in RA, a human immune-mediated inflammatory disease, blocking the TLR4 pathway alone does not improve disease parameters. Successful targeting of innate immune pathways in RA may require broader and/or earlier inhibitory approaches.