RAGE mRNA Expression Research Articles

Renal Protective Effect of Boeravinone B against Diabetic Nephropathy Rats via Inhibition of The Inflammatory and JAK2/STAT3 Signalling Pathway.

Chronic inflammation is a common feature in diabetes, especially when blood sugar levels are poorly controlled. This chronic low-grade inflammation can affect various organs, including the kidneys. Podocyte damage play a key role in the development of diabetic nephropathy (DN). The aim of the study was to evaluate the nephroprotective effect of Boeravinone B (BB) against streptozotocin (STZ) induced DN in rats and explore the underlying mechanism. In this experimental study, the rats received intraperitoneal injections of STZ (60 mg/kg) to induce DN. Various doses of BB (2.5, 5, and 7.5 mg/kg) were administered orally. Glucose levels, body weights, and organ weights (hepatic and renal) were assessed. Renal, histomorphological, antioxidant, hepatic, and cytokine levels were determined, as were the mRNA expression levels of JAK2 and STAT3. At end of the experimental study, the rats were sacrificed and their renal tissues were removed for histopathological assessment. BB treatment decreased glucose levels and increased body weights. This treatment suppressed hepatic weights, increased renal tissue weights, and also decreased renal parameters like uric acid, urea, bilirubin, creatinine (Cr) and, albumin. There was a decrease (P<0.001) in histomorphological parameters such as kidney hypertrophy index (KHI), mean glomerular volume (MGV), foot process fusion ratio (FPFR), and glomerular basement membrane thickness (GBMT) after treatment with BB. In addition, this treatment improved the levels of renal podocin, renal CD2- associated protein (CD2AP) and suppressed hepatic parameter levels. BB treatment (P<0.001) altered antioxidant parameters and cytokine levels, and suppressed mRNA expressions of JAK2, STAT3, RAGE, KIM-1, NAGL, and S100A8. Administration of BB showed renal protective effects against STZ-induced DN in rats via the reduction of oxidative stress and inflammatory reactions.

The effect of the HMGB1/RAGE/TLR4/NF-κB signalling pathway in patients with idiopathic epilepsy and its relationship with toxoplasmosis.

This study aims to investigate the relationship between toxoplasmosis and this pathway, which may be effective in the formation of epilepsy by acting through the HMGB1/RAGE/TLR4/NF-κB signalling pathway in patients with idiopathic epilepsy. In the study, four different experimental groups were formed by selecting Toxoplasma gondii IgG positive and negative patients with idiopathic epilepsy and healthy controls. Experimental groups were as follows: Group 1: Epilepsy+/Toxo- (E+, T-) (n = 10), Group 2: Epilepsy-/Toxo- (E-, T-) (n = 10), Group 3: Epilepsy-/Toxo+ (E-, T+) (n = 10), Group 4: Epilepsy+/Toxo+ (E+, T+) (n = 10). HMGB1, RAGE, TLR4, TLR1, TLR2, TLR3, IRAK1, IRAK2, IKBKB, IKBKG, BCL3, IL1β, IL10, 1 L8 and TNFα mRNA expression levels in the HMGB/RAGE/TLR4/NF-κB signalling pathway were determined by quantitative simultaneous PCR (qRT-PCR) after collecting blood samples from all patients in the groups. Statistical analysis was performed by one-way ANOVA followed by LSD post-hoc tests, and p < 0.05 was considered to denote statistical significance. The gene expression levels of HMGB1, TLR4, IL10, IL1B, IL8, and TLR2 were significantly higher in the G1 group than in the other groups (p < 0.05). In the G3 group, RAGE and BCL3 gene expression levels were significantly higher than in the other groups (p < 0.05). In the G4 group, however, IRAK2, IKBKB, and IKBKG gene expression levels were significantly higher than in the other groups (p < 0.05). HMGB1, TLR4, IRAK2, IKBKB, IL10, IL1B, IL1B, and IL8 in this signalling pathway are highly expressed in epilepsy patients in G1 and seizures occur with the stimulation of excitatory mechanisms by acting through this pathway. The signalling pathway in epilepsy may be activated by HMGB1, TLR4, and TLR2, which are considered to increase the level of proinflammatory cytokines. In T. gondii, this pathway is activated by RAGE and BCL3.

Puerarin alleviates the high glucose-induced oxidative stress via the RAGE/PKC/NOX4 axis in renal mesangial cells.

Diabetic nephropathy (DN) is a severe microvascular complication of diabetes, of which progression is related to high glucose (HG)-induced oxidative stress in renal mesangial cells. Our study aims to explore the antioxidant activity and the underlying mechanism of Puerarin (Pu) in renal mesangial cells exposed to HG. After the cells finished different treatments, DCFH-DA was used to detect the generation of ROS while the expression of AGE, MDA, SOD, and GSH-PX was measured by the ELISA and corresponding kits. The cell morphology was captured by optical microscopy. The mRNA expressions of RAGE, PKCα, PKCβ, PKCγ, and NOX4 were calculated by RT-PCR assays, while the protein expressions of RAGE, NOX4, and PKCβ were quantified via western blotting. Compared with the normal glucose (NG) group, the ROS level, SOD activity, and GSH-PX expression were markedly reduced in the HG group while the MDA expression was increased in the HG group. Then, Pu treatment was proved to significantly prevent the HG-induced up-regulation of ROS level, MDA expression, and down-regulation of SOD activity and GSH-PX expression. Besides, Pu treatment can notably inhibit the AGE expression and reverse the increased RAGE, PKCβ, and NOX4 expressions by HG environment at both RNA and protein levels. Moreover, the antioxidant effect of Pu against access glucose could not be observed in PKCβ knockdown cells. Pu can alleviate the HG-induced oxidative stress via the RAGE/PKC/NOX4 axis in renal mesangial cells, which innovatively suggests the therapeutic potential of Pu for DN treatment.

Myeloma extracellular vesicle-derived RAGE increases inflammatory responses and myotube atrophy in multiple myeloma through activation of theTLR4/NF-κB p65 pathway.

Sarcopenia manifests as muscle atrophy and loss that is complicated with malignancy. This study explored the mechanism of extracellular vesicles (EVs) in multiple myeloma (MM) with sarcopenia.SP2/0 conditioned medium (CM) was collected to isolate SP2/0-EVs. C2C12 cells were incubated with SP2/0 CM or SP2/0-EVs. ROS, TNF-α, IL-6, MuRF1 and MyHC levels were detected by DCF-DA fluorescent probe, ELISA, and Western blot. GW4869 was used to inhibit EV secretion in SP2/0 to confirm its effect on muscle atrophy. Serum was collected from MM patients with or without sarcopenia to detect RAGE mRNA expression. SP2/0 cells were transfected with RAGE siRNA and C2C12 cells were treated with the isolated si-RAGE-EVs or/and TLR4 agonist. SP2/0 tumor-bearing mouse model was established. Healthy mice and SP2/0-tumor bearing mice were treated with SP2/0-EVs or si-RAGE-EVs.SP2/0 CM or SP2/0-EVs stimulated ROS, inflammatory responses, and myotube atrophy in C2C12 cells. GW4869 blocked EV secretion and the effects of SP2/0 CM. RAGE mRNA expression in serum EVs was increased in MM&Sarcopenia patients and RAGE knockdown in SP2/0-EVs partially nullified SP2/0-EVs' effects. SP2/0-EVs activated the TLR4/NF-κB p65 pathway by translocating RAGE. SP2/0-EVs-derived RAGE elevated ROS production, inflammation, and myotube atrophy in C2C12 cells and caused muscle loss in SP2/0 tumor-bearing mice by activating the TLR4/NF-κB p65 pathway. SP2/0-EVs partially recapitulated muscle loss in healthy mice.SP2/0-EVs-derived RAGE increased ROS production, inflammation, and myotube atrophy in MM through TLR4/NF-κB p65 pathway activation.

Gleditsiae sinensis fructus Pills combined with Jujubae fructus attenuate chronic bronchitis via regulation of AGE-RAGE signaling pathway

Ethnopharmacological relevanceGleditsiae sinensis fructus Pills (GF) is a famous classical prescription, that is regularly combined with Jujubae fructus (JF) for the treatment of chronic bronchitis (CB) in the clinic. While the clinical efficacy of this combination prescription is clearly established, the active ingredients and molecular mechanisms remain unclear. Aim of the studyTo elucidate the mechanisms of action of Gleditsiae sinensis fructus Pills combined with Jujubae fructus (GF&JF) against CB based on network pharmacology and experimental verification. Materials and methodsThe potential targets of GF&JF involved in therapeutic activity against CB were predicted based on network pharmacology and an “ingredients-targets” network constructed. The Metascape database was used for Module, GO functional and KEGG signaling pathway enrichment analyses of potential targets. Molecular docking was applied to simulate the binding activities of key candidate active ingredients to core targets. For experimental verification, a CB model was established through smoking and nasal cavity drip of lipopolysaccharide. Related inflammatory factors, including TNF-α, TGF-β, IL-6 and IL-8 in serum, and IL-4 IL-8, IFN-γ and IL-10 in bronchoalveolar lavage fluid (BALF), were detected using ELISA. Hematoxylin and eosin (H&E) and Masson staining were performed to observe pathological changes in lung and tracheal tissue. The expression of related proteins and mRNAs in the lung tissue were detected using immunohistochemistry (IHC), quantitative real-time PCR, and western blot. ResultsIn network pharmacology, 36 common targets of GF&JF for CB were screened and the key targets and main signaling pathways identified. The active ingredients quercetin and stigmasterol in GF&JF had more targets for CB, which displayed good binding activity to IL-6, VEGFA, and EGFR, as established from molecular docking results. In vivo, GF&JF effectively inhibit the inflammatory response in CB mice and improved pathological changes in lung and tracheal tissue. In terms of the key proteins of the AGE-RAGE signaling pathway, GF&JF induced significant down-regulation of IL-6, ICAM-1, VCAM-1, EGFR, CASPASE-3, AGEs and RAGE proteins in lung tissue as well as mRNA expression of IL-6, ICAM-1, VCAM-1, EGFR, AGEs and RAGE. ConclusionsThe GF&JF combination exerts a good therapeutic effect in CB model mice, which may be attributed to inhibition of the inflammatory response as well as regulation on the expression of AGE-RAGE signaling pathway. In addition, quercetin and stigmasterol appear to be the main active ingredients of GF&JF in the treatment of CB.

Effect of Vitamin D on the HMGB1/RAGE Pathway and Adipokines Levels in Obese Asthmatic Mice.

Compared to common asthma, obese asthma is difficult to control. Previous studies have shown that vitamin D (Vit D) has a therapeutic effect on asthma. Nevertheless, the action mechanism of Vit D for obese asthma are not well known. In this study, we, therefore, induced obesity and established an obese asthma mouse model using ovalbumin (OVA) stimulation and applied treatment with Vit D (100 ng/kg). Accordingly, thirty mice were randomly divided into 5 equal groups of normal control, asthma, obese asthma, asthma+Vit D, and obese asthma+ Vit D. The levels of inflammatory factors and adipokines were measured by the ELISA assay; then the quantitative reverse transcription PCR (qRT-PCR) method was used to evaluate the expression of high mobility group box 1(HMGB1) and receptor for advanced glycation end products [RAGE] genes.T he results showed that OVA sensitization significantly increased airway resistance, the levels of inflammatory cytokines, and HMGB and RAGE expression in asthmatic and obese asthmatic mice, as compared to the control group. Also, these changes in the obese asthmatic group were notably higher than those in the asthmatic one. In addition, the treatment of asthmatic and obese asthmatic mice with Vit D significantly reduced the raw, serum and BALF levels of inflammatory cytokines, as well as the expression of HMGB1 and RAGE mRNA. To conclude, the present study showed that vitamin D might attenuate lung injury by up-regulating HMGB1 and RAGE expression. Our findings, thus, may offer new concepts and approaches for the treatment and prevention of obese asthma.

Compound Tinglizi Decoction intervenes COPD-associated pulmonary hypertension through regulation of HMGB1-mediated pyroptosis and immune imbalance

This paper aimed to investigate the effects of high mobility group box 1(HMGB1)-mediated pulmonary artery smooth muscle cell pyroptosis and immune imbalance on chronic obstructive pulmonary disease-associated pulmonary hypertension(COPD-PH) in rats and the intervening mechanism of Compound Tinglizi Decoction. Ninety rats were randomly divided into a normal group, a model group, low-dose, medium-dose, and high-dose Compound Tinglizi Decoction groups, and a simvastatin group. The rat model of COPD-PH was established by fumigation combined with lipopolysaccharide(LPS) intravascular infusion, which lasted 60 days. Rats in the low, medium, and high-dose Compound Tinglizi Decoction groups were given 4.93, 9.87, and 19.74 g·kg~(-1) Compound Tinglizi Decoction by gavage, respectively. Rats in the simvastatin group were given 1.50 mg·kg~(-1) simvastatin by gavage. After 14 days, the lung function, mean pulmonary artery pressure, and arterial blood gas of rats were analyzed. Lung tissues of rats were collected for hematoxylin-eosin(HE) staining to observe the pathological changes. Real-time fluorescent quantitative polymerase chain reaction(qRT-PCR) was used to determine the expression of related mRNA in lung tissues, Western blot(WB) was used to determine the expression of related proteins in lung tissues, and enzyme linked immunosorbent assay(ELISA) was used to determine the levels of inflammatory factors in the lung tissues of rats. The ultrastructure of lung cells was observed by transmission electron microscope. The forced vital capacity(FVC), forced expiratory volume in 0.3 second(FEV_(0.3)), FEV_(0.3)/FVC, peek expiratory flow(PEF), respiratory dynamic compliance(Cdyn), arterial partial pressure of oxygen(PaO_2), and arterial oxygen saturation(SaO_2) were increased, and resistance of expiration(Re), mean pulmonary arterial pressure(mPAP), right ventricular hypertrophy index(RVHI), and arterial partial pressure of carbon dioxide(PaCO_2) were decreased by Compound Tinglizi Decoction in rats with COPD-PH. Compound Tinglizi Decoction inhibited the protein expression of HMGB1, receptor for advanced glycation end products(RAGE), pro caspase-8, cleaved caspase-8, and gasdermin D(GSDMD) in lung tissues of rats with COPD-PH, as well as the mRNA expression of HMGB1, RAGE, and caspase-8. Pulmonary artery smooth muscle cell pyroptosis was inhibited by Compound Tinglizi Decoction. Interferon-γ(IFN-γ) and interleukin-17(IL-17) were reduced, and interleukin-4(IL-4) and interleukin-10(IL-10) were incresead by Compound Tinglizi Decoction in lung tissues of rats with COPD-PH. In addition, the lesion degree of trachea, alveoli, and pulmonary artery in lung tissues of rats with COPD-PH was improved by Compound Tinglizi Decoction. Compound Tinglizi Decoction had dose-dependent effects. The lung function, pulmonary artery pressure, arterial blood gas, inflammation, trachea, alveoli, and pulmonary artery disease have been improved by Compound Tinglizi Decoction, and its mechanism is related to HMGB1-mediated pulmonary artery smooth muscle cell pyroptosis and helper T cell 1(Th1)/helper T cell 2(Th2), helper T cell 17(Th17)/regulatory T cell(Treg) imbalance.

RAGE-TLR4 Crosstalk Is the Key Mechanism by Which High Glucose Enhances the Lipopolysaccharide-Induced Inflammatory Response in Primary Bovine Alveolar Macrophages.

The receptor of advanced glycation end products (RAGE) and Toll-like receptor 4 (TLR4) are important receptors for inflammatory responses induced by high glucose (HG) and lipopolysaccharide (LPS) and show crosstalk phenomena in inflammatory responses. However, it is unknown whether RAGE and TLR4 can influence each other's expression through a crosstalk mechanism and whether the RAGE-TLR4 crosstalk related to the molecular mechanism of HG enhances the LPS-induced inflammatory response. In this study, the implications of LPS with multiple concentrations (0, 1, 5, and 10 μg/mL) at various treatment times (0, 3, 6, 12, and 24 h) in primary bovine alveolar macrophages (BAMs) were explored. The results showed that a 5 μg/mL LPS treatment at 12 h had the most significant increment on the pro-inflammatory cytokine interleukin 1β (IL-1β), IL-6, and tumor necrosis factor (TNF)-α levels in BAMs (p < 0.05) and that the levels of TLR4, RAGE, MyD88, and NF-κB p65 mRNA and protein expression were upregulated (p < 0.05). Then, the effect of LPS (5 μg/mL) and HG (25.5 mM) co-treatment in BAMs was explored. The results further showed that HG significantly enhanced the release of IL-1β, IL-6, and TNF-α caused by LPS in the supernatant (p < 0.01) and significantly increased the levels of RAGE, TLR4, MyD88, and NF-κB p65 mRNA and protein expression (p < 0.01). Pretreatment with FPS-ZM1 and TAK-242, the inhibitors of RAGE and TLR4, significantly alleviated the HG + LPS-induced increment of RAGE, TLR4, MyD88, and NF-κB p65 mRNA and protein expression in the presence of HG and LPS (p < 0.01). This study showed that RAGE and TLR4 affect each other's expression through crosstalk during the combined usage of HG and LPS and synergistically activate the MyD88/NF-κB signaling pathway to promote the release of pro-inflammatory cytokines in BAMs.

Abstract 3947: S100A8/A9-RAGE pathway and chronic airway inflammation in cigarette smoke-induced lung carcinogenesis

Abstract Background: Cigarette smoke-induced chronic airway inflammation increases the risk of lung cancer, and plays a multifaceted role in lung cancer initiation and progression, and RAGE-ligand axis (HMGB1, S100A8/A9) contributes Cigarette smoke-induced persistent and progressive inflammation. The aim of the present study was to determine the inflammatory effect on S100A8/A9-RAGE pathway in smoke-induced carcinogenesis in lung cancer. Methods: Human alveolar adenocarcinoma cells (A549) and normal bronchial epithelial cells (BEAS-2B) were co-cultured for 24 h with the PBMC and then, cells were incubated in the presence or absence of 1.5% cigarette smoke extract (CSE) for 24 h. The cells transfected with siRNA targeting S100A8/9 or RAGE. The cell viability, colony-forming ability, migration, invasion, metastasis and morphological changes were assessed. Female A/J mice were given a benzo(a)pyrene (100mg/kg) in 0.1 ml corn oil via oral gavage at once a week for 3 weeks, and administrated CSE (1.25 ul/g) via intratracheal (IT) at twice a week for 4 weeks. Tumor load was determined by averaging the total tumor volume in each group. BAL differential cells were counted to analyze inflammatory cells. Results: Cellular growth and colony-forming were promoted by exposure to CSE, and significantly inhibited by S100A8/9 and RAGE-siRNA transfection, especially in A549 cells than BEAS-2B. Cell migration, invasion, MMP-2/9 activities, and the mRNA and protein expression of TLR4, NF-κB, RAGE, S100A8/9 and HMBG1 were higher in CSE exposed A549 cells. S100A8/9 and RAGE-siRNA transfection attenuated those expression, significantly. B(a)P induced an average tumor volume 7.28 mm3 per mouse, and CSE significantly increased tumor volume (8.10 mm3) compared to the B(a)P group. The total cell number and lymphocytes in BAL fluids tended to increase after CSE administration in lung cancer mouse group. Moreover, CSE significantly induced the levels of S100A8/9 and RAGE, p38 and p-ERK, and decreased JNK in serum and tumors with adjacent lung tissues (p &amp;lt; 0.05). Conclusions: We identified cigarette smoke-induced S100A8/A9-RAGE pathway promoted airway inflammation and lung carcinogenesis in vitro and in vivo. Although S100A8/A9 protein contributes to many types of disease, this study will help us gain a better understanding of the complexities of cancer progression. Further studies are needed for therapeutic target of cigarette smoke-induced inflammation and immunosuppression in tumor microenviornment. Citation Format: Hye Seon Kang, In Kyoung Kim, Chang Dong Yeo, Jin Woo Kim, Sang Haak Lee. S100A8/A9-RAGE pathway and chronic airway inflammation in cigarette smoke-induced lung carcinogenesis. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3947.

Bone-Marrow-Derived Mesenchymal Stem Cells Attenuate Behavioral and Cognitive Dysfunction after Subarachnoid Hemorrhage via HMGB1-RAGE Axis Mediation.

We evaluated the therapeutic effects of bone-marrow-derived mesenchymal stem cells (BMSCs) on behavioral and cognitive function in a mouse model of mild subarachnoid hemorrhage (SAH) and explored the underlying mechanisms in conjunction with the HMGB1-RAGE axis. The SAH models were generated in a total of 126 male C57BL/6J mice via endovascular perforation and evaluated 24 h and 72 h after the intravenous administration of BMSCs (3 × 105 cells). The BMSCs were administered once, at 3 h, or twice, at 3 h and 48 h after the model induction. The therapeutic effects of the BMSCs were compared to those of the saline administration. Compared to saline-treated SAH-model mice, at 3 h, the mice with mild SAH treated with the BMSCs showed significant improvements in their neurological scores and cerebral edema. The administration of the BMSCs decreased the mRNA expression of HMGB1, RAGE, TLR4, and MyD88, as well as the protein expression of HMGB1 and phosphorylated NF-kB p65. Furthermore, the numbers of slips per walking time, impairments in short-term memory, and the recognition of novel objects were improved. There was some improvement in inflammatory-marker levels and cognitive function according to the BMSCs' administration times, but no large differences were seen. The administration of BMSCs improved behavioral and cognitive dysfunction by ameliorating HMGB1-RAGE axis-mediated neuroinflammation after SAH.

Glycyrrhizin Interacts with TLR4 and TLR9 to Resolve P. aeruginosa Keratitis.

This study tests the mechanism(s) of glycyrrhizin (GLY) protection against P. aeruginosa keratitis. Female C57BL/6 (B6), TLR4 knockout (TLR4KO), myeloid specific TLR4KO (mTLR4KO), their wildtype (WT) littermates, and TLR9 knockout (TLR9KO) mice were infected with P. aeruginosa KEI 1025 and treated with GLY or PBS onto the cornea after infection. Clinical scores, photography with a slit lamp, RT-PCR and ELISA were used. GLY effects on macrophages (Mϕ) and polymorphonuclear neutrophils (PMN) isolated from WT and mTLR4KO and challenged with KEI 1025 were also tested. Comparing B6 and TLR4KO, GLY treatment reduced clinical scores and improved disease outcome after infection and decreased mRNA expression levels in cornea for TLR4, HMGB1, and RAGE in B6 mice. TLR9 mRNA expression was significantly reduced by GLY in both mouse strains after infection. GLY also significantly reduced HMGB1 (B6 only) and TLR9 protein (both B6 and TLR4KO). In TLR9KO mice, GLY did not significantly reduce clinical scores and only slightly improved disease outcome after infection. In these mice, GLY significantly reduced TLR4, but not HMGB1 or RAGE mRNA expression levels after infection. In contrast, in the mTLR4KO and their WT littermates, GLY significantly reduced corneal disease, TLR4, TLR9, HMGB1, and RAGE corneal mRNA expression after infection. GLY also significantly reduced TLR9 and HMGB1 corneal protein levels in both WT and mTLR4KO mice. In vitro, GLY significantly lowered mRNA expression levels for TLR9 in both Mϕ and PMN isolated from mTLR4KO or WT mice after incubation with KEI 1025. In conclusion, we provide evidence to show that GLY mediates its effects by blocking TLR4 and TLR9 signaling pathways and both are required to protect against disease.

Flavonoids Ameliorate Stress-Induced Depression by Preventing NLRP3 Inflammasome Priming

ObjectivesChronic stress activates danger-associated molecular patterns (DAMPs), stimulating the NLRP3 inflammasome. NLRP3 activation triggers the release of pro-inflammatory cytokine IL‐1β. The activity of the NLRP3 inflammasome propagates pro-inflammatory signaling cascades implicated in the onset of depression. Our previous studies show that polyphenolic compounds were found to ameliorate stress induced depression in mouse models. However, the relevant mechanism has not been identified. This study examined the effect of administering polyphenols on DAMP signaling in enriched mice microglia.MethodsThis study examined the effect of administering polyphenols on DAMP signaling in mice microglia. To recapitulate stress-induced depression, mice underwent chronic unpredictable stress (CUS). Microglia were isolated at various time points throughout the CUS protocol. We also assessed long-term persistent changes after CUS and susceptibility to subthreshold unpredictable stress (US) re-exposure.ResultsInterestingly, the development of US-induced depression and anxiety depended upon a previous exposure to CUS. We found that CUS caused robust upregulation of IL-1β mRNA in enriched microglia, an effect that persists for up to 4 weeks following CUS exposure. Following the subthreshold US re-exposure, we observed the upregulation of pro- IL-1β as well as pro-receptor for advanced glycation end products (RAGE). Toll-like receptor 4 (TLR-4) was not. We also observed an increase in RAGE mRNA expression when mice were exposed to US prior to the start of the CUS paradigm. Importantly, a primary exposure to US, was sufficient to increase RAGE mRNA expression. We found that polyphenol administration significantly improved CUS-induced depressive-like phenotypes and also reversed neuroinflammation in mice. Treatment with dietary flavonoids prevented upregulation of IL-1β, RAGE mRNA, which reflects the ability of polyphenols that may have begun following the primary exposure to US.ConclusionsTaken all together, the results provide evidence of the role of dietary polyphenols in preventing persistent microglial activation, which has been shown to result in reduced long term vulnerability to depressive-like behaviors following expose to chronic stress.Funding SourcesThis study was supported by a P50 CARBON Center grant from the NCCIH/ODS.

Glucagon-like peptide-1 attenuates diabetes-associated osteoporosis in ZDF rat, possibly through the RAGE pathway

BackgroundDiabetes-associated osteoporosis are partly caused by accumulation of advanced glycation endproducts (AGEs). Glucagon-like peptide-1 (GLP-1) has been shown to regulate bone turnover. Here we explore whether GLP-1 receptor agonist (GLP1RA) can have a beneficial effect on bone in diabetes by ameliorating AGEs.MethodsIn the present study, we evaluated the effects of the GLP-1 receptor agonist liraglutide, insulin and dipeptidyl peptidase-4 inhibitor saxagliptin on Zucker diabetic fatty rats. Meanwhile, we observed the effect of GLP-1 on AGEs-mediated osteoblast proliferation and differentiation and the signal pathway.ResultsLiraglutide prevented the deterioration of trabecular microarchitecture and enhanced bone strength. Moreover, it increased serum Alpl, Ocn and P1NP levels and decreased serum CTX. In vitro we confirmed that GLP-1 could attenuate AGEs-mediated damage in osteogenic proliferation and differentiation. Besides, GLP-1 down-regulated the ROS that caused by AGEs and the mRNA and protein expression of Rage .ConclusionsAltogether, our findings suggest that GLP-1 receptor agonist promotes osteoblastogenesis and suppresses bone resorption on obese type 2 diabetic rats to a certain degree. The mechanism of these effects may be partly mediated by AGEs-RAGE-ROS pathway via the interaction with GLP-1 receptor.

Pro‐Inflammatory Profiling Of RAGE Targeted Mice Following Short‐Term Tobacco Exposure

Inflammation underpins pulmonary disease progression during tobacco smoke exposure that may culminate in irreversdible pulmonary remodeling. While primary smoke poses notable risk, nearly half of the US population is also at risk due to exposure to secondhand smoke (SHS). In the present study, we assessed a potential role for RAGE, a cell‐surface pattern recognition receptor implicated in pro‐inflammatory signaling, following exposure to SHS. Specifically, we used wild type, RAGE null, and lung‐specific RAGE overexpressing transgenic (TG) mice and evaluated the elaboration of inflammatory mediators in bronchoalveolar lavage fluid (BALF). Select mice were administered semi‐synthetic glycosaminoglycan ethers (SAGEs), a family of anionic, partially lipophilic sulfated polysaccharide derivatives known to inhibit RAGE signaling. Mice were exposed to room air (RA) or SHS from three Kentucky 3R4F research cigarettes via a nose‐only delivery system (Sireq Scientific, Montreal, Canada) five days a week and ip injections of PBS or SAGE (a 30mg/kg body weight) occurred three times per week from PN40 until sacrifice date on PN70. RAGE mRNA and protein expression was elevated in wild type and TG mice following SHS exposure and no expression was detected in RAGE nulls. BALF analyses revealed RAGE‐mediated control of leukocyte extravasation and a multiplex cytokine array confirmed a role for RAGE in the coordination of pro‐inflammatory chemokine/cytokine secretion. Among other mediators, TNF‐a, MIP‐2, and IL‐1b were each differentially secreted by lung tissue following SHS exposure and concentrations were significantly decreased in BALF from exposed RAGE null or wild type mice concomitantly administered SAGEs. In summary, inflammatory responses induced by SHS exposure were influenced by the availability of RAGE, as evidenced by RAGE nulls and SAGE treatment. These data reveal fascinating data suggesting the utility of RAGE abrogation in lessening smoke‐induced pulmonary exacerbations.

Enhanced RAGE Expression and Excess Reactive-Oxygen Species Production Mediates Rho Kinase-Dependent Detrusor Overactivity After Methylglyoxal Exposure

Methylglyoxal (MGO) is a highly reactive dicarbonyl compound implicated in diabetes-associated diseases. In vascular tissues, MGO induces the formation of advanced glycation end products (AGEs) that bounds its receptor RAGE, initiating the downstream tissue injury. Outside the cardiovascular system, MGO intake produces mouse voiding dysfunction and bladder overactivity. We have sought that MGO-induced bladder overactivity is due to activation of AGE-RAGE-reactive-oxygen species (ROS) signaling cascade, leading to Rho kinase activation. Therefore, female mice received 0.5% MGO orally for 12 weeks, after which in vitro bladder contractions were evaluated in the presence or not of superoxide dismutase (PEG-SOD) or the Rho kinase inhibitor Y27632. Treatment with MGO significantly elevated the serum levels of MGO and fluorescent AGEs, as well as the RAGE immunostaining in the urothelium, detrusor, and vascular endothelium. RAGE mRNA expression in the bladder was also higher in the MGO group. Methylglyoxal significantly increased the ROS production in both urothelium and detrusor smooth muscle, with the increases in detrusor markedly higher than urothelium. The bladder activity of superoxide dismutase (SOD) was significantly reduced in the MGO group. Gene expressions of L-type Ca2+ channels, RhoA, ROCK-1, and ROCK-2 in bladder tissues were significantly elevated in the MGO group. Increased bladder contractions to electrical-field stimulation, carbachol α,β-methylene ATP, and extracellular Ca2+ were observed after MGO exposure, which was significantly reduced by prior incubation with either PEG-SOD or Y27632. Overall, our data indicate serum MGO accumulation elevates the AGEs levels and activates the RAGE-ROS signaling leading to Rho kinase-induced muscle sensitization, ultimately leading to detrusor overactivity.

Methylglyoxal Exacerbates Lipopolysaccharide-Induced Acute Lung Injury via RAGE-Induced ROS Generation: Protective Effects of Metformin.

PurposeMethylglyoxal (MGO) is a highly reactive dicarbonyl species implicated in diabetic-associated diseases. Acute lung injury (ALI) symptoms and prognosis are worsened by diabetes and obesity. Here, we hypothesized that elevated MGO levels aggravate ALI, which can be prevented by metformin. Therefore, this study evaluated the lung inflammation in lipopolysaccharide (LPS)-exposed mice pretreated with MGO.MethodsC57Bl/6 male mice treated or not with MGO for 12 weeks were intranasally instilled with LPS (30 µg) to induce ALI, and metformin (300 mg/kg) was given as gavage in the last two weeks of treatment. After 6 h, bronchoalveolar lavage fluid (BALF) and lung tissues were collected to quantify the cell infiltration, cytokine levels, reactive-oxygen species (ROS) production, and RAGE expression.ResultsLPS exposure markedly increased the neutrophil infiltration in BALF and lung tissue, which was accompanied by higher levels of IFN-γ, TNF-α and IL-1β compared with untreated group. MGO treatment significantly increased the airways neutrophil infiltration and mRNA expressions of TNF-α and IL-1β, whereas COX-2 expression remained unchanged. In lung tissues of LPS-exposed mice, MGO treatment significantly increased the immunostaining and mRNA expression of RAGE, and the ROS levels. Serum MGO concentration achieved after 12-week intake was 9.2-fold higher than control mice, which was normalized by metformin treatment. Metformin also reduced the inflammatory markers in response to MGO.ConclusionMGO intake potentiates the LPS-induced ALI, increases RAGE expression and ROS generation, which is normalized by metformin. MGO scavengers may be a good adjuvant therapy to reduce ALI in patients with cardiometabolic diseases.

High mobility group box-1 (HMGB-1) and its receptors in the pathogenesis of malaria-associated acute lung injury/acute respiratory distress syndrome in a mouse model

The DNA-binding protein high mobility group box-1 (HMGB-1) mediates proinflammatory cytokines that contribute to acute lung injury (ALI). Although ALI is a frequent complication of malaria infection, the contribution of HMGB-1 and its receptors to the pathogenesis of malaria-associated ALI/acute respiratory distress syndrome (MA-ALI/ARDS) has not been investigated in a mouse model. Here, the malaria-infected mice were divided into two groups according to lung injury score: the ALI/ARDS and non-ALI/ARDS groups. The expression of HMGB-1 and its receptors (RAGE, TLR-2 and TLR-4) in lung tissues was investigated by using immunohistochemical staining and real-time polymerase chain reaction (PCR). Additionally, HMGB-1 and proinflammatory cytokine (TNF-α, IFN-γ, IL-1 and IL-6) levels in plasma and lung tissues were quantified by using enzyme-linked immunosorbent assays. Cellular expression of both HMGB-1 and its receptors (RAGE, TLR-2 and TLR-4) was significantly increased in the lung tissues of the ALI/ARDS group compared with those in the non-ALI/ARDS and control groups. The levels of HMGB-1, TNF-α, IFN-γ, IL-1 and IL-6 were significantly increased in both plasma and lung tissues of the ALI/ARDS group compared with those in the non-ALI/ARDS and control groups, which were similar to the results obtained by real-time PCR. Increased mRNA expression of RAGE, TLR-2 and TLR-4 was found in the lung tissues of the ALI/ARDS group. Furthermore, the plasma HMGB-1 level was positively correlated with TLR-4 mRNA expression in the ALI/ARDS group. HMGB-1 levels were significantly increased in plasma and lung tissues of MA-ALI/ARDS mice and were related to the upregulated expression of HMGB-1 and proinflammatory cytokines. In conclusion, this study demonstrates that HMGB-1 is an important mediator of MA-ALI/ARDS pathogenesis and may represent a target for therapeutic malaria interventions with ALI/ARDS.

The Potential Anti-Inflammatory Effects of Brucea javanica (L.) Merr.

Inflammation is the initial response to acute and chronic tissue damage, which is characterized by redness, swelling, heat, and pain. Natural products derived from plants have specific pharmacological activity and minimal side effects. Brucea javanica is a plant that has an anti-inflammatory effect, this plant contains alkaloid and flavonoid compounds. Flavonoids have the ability to block cyclooxygenase and lipoxygenase while alkaloids as an anti-inflammatory are thought to work by inhibiting prostaglandin H2 PGH2 which is an inflammatory mediator. From the data obtained, there is no complete literature that reviews its use as an anti-inflammatory. The search databases used are as follows: Pubmed, ScienceDirect, and Google Scholar to study the anti-inflammatory activity of Brucea javanica. All recent research articles were published between 2010 to 2021. Based on eligibility, 4 studies were included in this study, consisting of 2 In vivo studies and 2 In vitro and In vivo studies. A series of pharmacological studies have reported that Brucea javanica can block the Nf-kB signaling pathway and decrease the production of inflammatory mediators. It has been reported to be able to inhibit the production of NO, PGE2, TNF-, IL-1β, IL-18IL-23, COX-2, NF-κB, IFN-γ, IL-6, the levels of MPO (Myeloperoxidase), reducing the edema and induce the production of the anti-inflammatory cytokine (IL-4, IL-10 and TGF-β). Brucea javanica also markedly activates Nrf2 expression suppressing the inflammatory response-mediated NLRP3 and NF-κB activation. In addition, the elevated mRNA expression of MMP-1, MMP-3 and RAGE was remarkably inhibited by Brucea javanica, while the mRNA expression of PPAR-γ was significantly enhanced. In vitro and in vivo studies strongly indicate that Brucea javanica has the potential as an anti-inflammatory.

Gycyrrhizic acid alleviates atherosclerotic lesions in rats with diabetes mellitus.

Gycyrrhizic acid (GA), an inhibitor of high mobility group box 1 (HMGB1), inhibits inflammatory responses and is involved in the occurrence and development of several inflammation-related diseases. However, the role of GA in the atherosclerotic lesions caused by diabetes mellitus (DM) remains unknown. In the present study, Sprague Dawley rats were selected to desi=gn a diabetic atherosclerosis (AS) model. Rats from the DM-AS group were subsequently divided into DM-AS, DM-AS + GA (50 mg/kg) and DM-AS + GA (150 mg/kg) groups. Biochemical analyzers were used to measure levels of blood glucose, fasting insulin, total cholesterol, total triglyceride, low-density lipoprotein and high-density lipoprotein. The number of plaques was recorded after collection of thoracic aortas from the rats. The intimal thickness of arterial tissue was detected by hematoxylin and eosin staining. The expression levels of CD68 and α-smooth muscle actin (α-SMA) were detected by immunohistochemistry. The expression of tumor necrosis factor-α, interleukin (IL)-6 and IL-1β in the serum of the rats was detected by ELISA. The expression of fatty acid synthetase, sterol regulatory element binding protein 1C, HMGB1 and receptor for advanced glycation end products (RAGE) was detected by western blotting. Reverse transcription quantitative PCR was used to detect the mRNA expression of HMGB1 and RAGE. The results demonstrated that GA treatment could decrease the body weight, blood glucose level and biochemical parameters of AS DM rats in a dose-dependent manner. In addition, GA decreased the intimal thickness of carotid artery and the formation of plaque in rats with diabetic AS. Furthermore, GA inhibited macrophage activation and decreased α-SMA expression in vascular smooth muscle cells, and decreased the expression of proteins (FAS and SREBP-1c) and inflammatory factors. Taken together, the findings from the present study demonstrated that GA may have a therapeutic effect on DM-associated AS. This study provides a theoretical basis for the treatment of diabetic AS.

Crocetin suppresses gestational diabetes in streptozotocin-induced diabetes mellitus rats via suppression of inflammatory reaction.

Gestational diabetes mellitus (GDM) is the serious complication of pregnancy induced via dysfunction in glucose metabolism during the pregnancy. Crocetin already proved antidiabetic effect in streptozotocin (STZ)-induced diabetes mellitus in rats. In this protocol, we have investigated the potential effect of crocetin against STZ-induced GDM in rats. Wistar rats were used for the current protocol; STZ was used for the induction for DM and finally caused the GDM. Body weight and serum advanced glycation end products level were estimated at regular time intervals. We also estimated the fetus weight and placental weight. Biochemical, antioxidant, pro-inflammatory cytokines, inflammatory mediators, and apoptosis parameters were estimated. mRNA expression of NOX2, RAGE, MCP-1, VCAM-1, EGFR, and p65 were also estimated. Crocetin treatment significantly (p<.001) reduced the fetus weight and increased the placental weight and index. Crocetin significantly (p<.001) reduced the blood glucose level and increased the body weight. Crocetin significantly (p<.001) boosted the level of antioxidant enzymes and includes superoxide dismutase, glutathione peroxidase, glutathione, and catalase. Crocetin significantly (p<.001) altered the level of lipid parameters and pro-inflammatory cytokines. Crocetin significantly (p<.001) reduced the level of intercellular adhesion molecule 1, cyclooxygenase-2, and nuclear factor kappa B and increased the level of visfatin against GDM rats. Crocetin significantly (p<.001) altered the level of mRNA expression. Based on the result, we can say that crocetin is a protective drug against the GDM in pregnant rats via antioxidant, inflammatory, and apoptosis parameters. PRACTICAL APPLICATIONS: As we all know, gestational diabetes mellitus (GDM) cases rise all over the world. The current investigation showed the protective effect of crocetin on GDM in experimental rats. The current finding exhibited the protective effect of crocetin against STZ-induced GDM via suppression of inflammatory, oxidative, and apoptosis parameters. The result suggests the antioxidant and anti-inflammatory effect of crocetin. Crocetin can be used as a preventive medication in the treatment of gestational diabetes mellitus, according to the latest findings.