scholarly journals Lipopolysaccharide Pre-conditioning Attenuates Pro-inflammatory Responses and Promotes Cytoprotective Effect in Differentiated PC12 Cell Lines via Pre-activation of Toll-Like Receptor-4 Signaling Pathway Leading to the Inhibition of Caspase-3/Nuclear Factor-κappa B Pathway

2021 ◽  
Vol 14 ◽  
Author(s):  
Pushpa Gandi Sangaran ◽  
Zaridatul Aini Ibrahim ◽  
Zamri Chik ◽  
Zahurin Mohamed ◽  
Abolhassan Ahmadiani

Lipopolysacharide (LPS) pre-conditioning (PC), has been shown to exert protective effects against cytotoxic effects. Therefore, we hypothesized, the tolerance produced by LPS PC will be resulted by the alterations and modifications in gene and protein expression. With reference to the results of MTT assays, AO/PI staining, and Annexin V-FITC analyses of LPS concentration (0.7815–50 μg/mL) and time-dependent (12–72 h) experiments, the pre-exposure to 3 μg/mL LPS for 12 h protected the differentiated PC12 cells against 0.75 mg/mL LPS apoptotic concentration. LPS-treated cells secreted more inflammatory cytokines like IL-1α, IL-1β, IL-2, IL-3, IL-4, IL-6, IL-17, IFN-γ, and TNF-α than LPS-PC cells. The production of inflammatory mediators ROS and NO was also higher in the LPS-induced cells compared to LPS-PC cells. Conversely, anti-inflammatory cytokines (like IL-10, IL-13, CNTF, and IL-1Ra) were upregulated in the LPS-PC cells but not in the LPS-induced cells. Meanwhile, the LPS initiated caspase-8 which in turn activates effector caspase 3/7. When the activities of caspases in the LPS-induced cells were inhibited using z-VADfmk and z-DEVDfmk, the expressions of c-MYC and Hsp70 were increased, but p53 was reduced. The potential molecules associated with protective and destructive effect was measured by RT2 Profiler PCR array to elucidate the signaling pathways and suggested inhibition NF-κB/caspase-3 signaling pathway regulates the cytoprotective genes and proto-oncogenes. In conclusion, this study provides a basis for future research to better understand the molecular mechanism underlying LPS pre-conditioning /TLR4 pre-activation and its functional role in offering cytoprotective response in neuronal environment.

Author(s):  
Zhiguang Qiao ◽  
Jiaxin Tang ◽  
Wen Wu ◽  
Jian Tang ◽  
Ming Liu

Abstract Background Osteoarthritis (OA) is a common degenerative disease of synovial joints caused by inflammation. Acteoside (ACT), a major component and lipase inhibitor from the Chinese tea Ligustrum purpurascens kudingcha, has been reported to regulate the inflammation and immune response. The study aims to investigate the effects of ACT on inflammatory responses and joint protection in OA rats. Methods Cell proliferation was examined by MTT and colony formation assay. Apoptosis was analyzed using flow cytometry with Annexin V/PI staining. ELISA was employed to examine the concentration of inflammatory cytokines. OA rat model was established by surgery stimulation. Results ACT treatment significantly inhibited the upregulation of inflammatory cytokines induced by IL-1β in primary chondrocytes, including IL-6, IL-12, TNF-α and IFN-γ. ACT stimulation also enhanced the cell proliferation, while inhibited cell apoptosis in IL-1β-treated chondrocytes. Consistently, ACT treatment led to downregulation of cleaved-caspase-3 and apoptosis regulator Bax, and upregulation of Bcl-2. Furthermore, ACT treatment inhibited IL-1β-induced activation of JAK/STAT pathway. The results were confirmed in surgery-induced OA rat model. Moreover, ACT treatment significantly inhibited synovial inflammation and articular chondrocyte apoptosis in OA rats. Conclusion Our findings indicate that ACT has the potential therapeutic effect on OA through inhibiting the inflammatory responses via inactivating JAK/STAT signaling pathway.


2021 ◽  
pp. 096032712110237
Author(s):  
Y-J Li ◽  
D-Z Zhang ◽  
Y Xi ◽  
C-A Wu

Objective: To explore the mechanism of dexmedetomidine (DEX)-mediated miR-134 inhibition in hypoxia-induced damage in PC12 cells. Methods: Hydrogen peroxide (H2O2)-stimulated PC12 cells were divided into control, H2O2, DEX + H2O2, miR-NC/inhibitor + H2O2, and miR-NC/ mimic + DEX + H2O2 groups. Cell viability and apoptosis were assessed by the 3-(4,5-dimethylthiazol(-2-y1)-2,5-diphenytetrazolium bromide (MTT) assay and Annexin V-FITC/PI staining, while gene and protein expression levels were detected by qRT-PCR and western blotting. Reactive oxygen species (ROS) levels were tested by 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA) staining, and malondialdehyde (MDA) content was determined with a detection kit. Results: DEX treatment decreased H2O2-elevated miR-134 expression. H2O2-induced PC12 cell damage was improved by DEX and miR-134 inhibitor; additionally, cell viability was increased, while cell apoptosis was reduced. In addition, both DEX and miR-134 inhibitor reduced the upregulated expression of cleaved caspase-3 and increased the downregulated expression of Bcl-2 in H2O2-induced PC12 cells. However, compared to that in the DEX + H2O2 group, cell viability in the mimic + DEX + H2O2 group was decreased, and the apoptotic rate was elevated with increased cleaved caspase-3 and decreased Bcl-2 expression. Inflammation and oxidative stress were increased in H2O2-induced PC12 cells but improved with DEX or miR-134 inhibitor treatment. However, this improvement of H2O2-induced inflammation and oxidative stress induced by DEX in PC12 cells could be reversed by the miR-134 mimic. Conclusion: DEX exerts protective effects to promote viability and reduce cell apoptosis, inflammation, and oxidative stress in H2O2-induced PC12 cells by inhibiting the expression of miR-134.


Nutrients ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2794 ◽  
Author(s):  
Cao ◽  
Chen ◽  
Ren ◽  
Zhang ◽  
Tan ◽  
...  

Punicalagin, a hydrolysable tannin of pomegranate juice, exhibits multiple biological effects, including inhibiting production of pro-inflammatory cytokines in macrophages. Autophagy, an intracellular self-digestion process, has been recently shown to regulate inflammatory responses. In this study, we investigated the anti-inflammatory potential of punicalagin in lipopolysaccharide (LPS) induced RAW264.7 macrophages and uncovered the underlying mechanisms. Punicalagin significantly attenuated, in a concentration-dependent manner, LPS-induced release of NO and decreased pro-inflammatory cytokines TNF-α and IL-6 release at the highest concentration. We found that punicalagin inhibited NF-κB and MAPK activation in LPS-induced RAW264.7 macrophages. Western blot analysis revealed that punicalagin pre-treatment enhanced LC3II, p62 expression, and decreased Beclin1 expression in LPS-induced macrophages. MDC assays were used to determine the autophagic process and the results worked in concert with Western blot analysis. In addition, our observations indicated that LPS-induced releases of NO, TNF-α, and IL-6 were attenuated by treatment with autophagy inhibitor chloroquine, suggesting that autophagy inhibition participated in anti-inflammatory effect. We also found that punicalagin downregulated FoxO3a expression, resulting in autophagy inhibition. Overall these results suggested that punicalagin played an important role in the attenuation of LPS-induced inflammatory responses in RAW264.7 macrophages and that the mechanisms involved downregulation of the FoxO3a/autophagy signaling pathway.


2019 ◽  
Vol 39 (8) ◽  
Author(s):  
Yao Ming-yan ◽  
Zhang Jing ◽  
Guo Shu-qin ◽  
Bai Xiao-liang ◽  
Li Zhi-hong ◽  
...  

Abstract Diabetes mellitus (DM) is a potential etiology of disc degeneration. Glucagon-like peptide-1 (GLP-1) is currently regarded as a powerful treatment option for type 2 diabetes. Apart from the beneficial effects on glycaemic control, GLP-1 has been reported to exert functions in a variety of tissues on modulation of cell proliferation, differentiation, and apoptosis. However, little is known regarding the effects of GLP-1 on nucleus pulposus cells (NPCs). In the present study, we investigated the effects of liraglutide (LIR), a long-lasting GLP-1 analogue, on apoptosis of human NPCs and the underlying mechanisms involved. We confirmed the presence of GLP-1 receptor (GLP-1R) in NPCs. Our data demonstrated that liraglutide inhibited the apoptosis of NPCs induced by high glucose (HG), as detected by Annexin V/Propidium Iodide (PI) and ELISA assays. Moreover, liraglutide down-regulated caspase-3 activity at intermediate concentration (100 nM) for maximum effect. Further analysis suggested that liraglutide suppressed reactive oxygen species (ROS) generation and stimulated the phosphorylation of Akt under HG condition. Pretreatment of cells with the Phosphoinositide 3-kinase (PI3K) inhibitor LY294002 (LY) and small interfering RNAs (siRNAs) GLP-1R abrogated the liraglutide-induced activation of Akt and the protective effects on NPCs’ apoptosis. In conclusion, liraglutide could directly protect NPCs against HG-induced apoptosis by inhibiting oxidative stress and activate the PI3K/Akt/caspase-3 signaling pathway via GLP-1R.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Juan Zhang ◽  
Jiangang Song ◽  
Jin Xu ◽  
Xuemei Chen ◽  
Peihao Yin ◽  
...  

Early growth response- (Egr-) 1 is an upstream master switch in controlling inflammatory responses following myocardial ischemia-reperfusion (I/R). Activation of extracellular signal-regulated protein kinase-1 and kinase-2 (ERK1/2) signaling is known to upregulate Egr-1. ERK1/2 pathway has been previously shown to mediate the therapeutic action of electroacupucture (EA). Thus, we hypothesized that EA would reduce myocardial I/R injury and inflammatory responses through inhibiting Egr-1 expression via the ERK1/2 pathway. Mice were pretreated with EA, U0126, or combination of EA and U0126 and then underwent 1 h myocardial ischemia and 3 h reperfusion. We investigated that EA significantly attenuated the I/R-induced upregulation of both Egr-1 and phosporylated-ERK1/2 (p-ERK1/2), decreased myocardial inflammatory cytokines including tumor necrosis factor-α(TNF-α) and interleukin-1β(IL-1β), and reduced the infarct size and the release of cardiac troponin I (cTnI). U0126 treatment also exhibited the same effect as EA on Egr-1 level and subsequent cardioprotective effects. There was no additive effect of cotreatment with EA and U0126 on the expression of Egr-1 and its downstream target genes (TNF-α, IL-1β) or serum cTnI level. Collectively, these observations suggested that EA attenuates myocardial I/R injury, possibly through inhibiting the ERK1/2-Egr-1 signaling pathway and reducing the release of proinflammatory cytokines.


2020 ◽  
Author(s):  
Jin Xu ◽  
Xiaozhong Qian ◽  
Ren Ding

Abstract Background: Osteoarthritis (OA) is a chronic and degenerative joint disease prevalent in the elderly. MiR-24-3p has been reported to be involved in an OA-resembling environment. However, the functional role and underlying mechanism of miR-24-3p in chondrocyte injury associated with OA remains unknown. Methods: The expression of miR-24-3p was determined in OA cases and control patients, as well as IL-1β-stimulated chondrocyte cell line CHON-001 using reverse transcription quantitative PCR analysis. Cell viability was analyzed by CCK-8 assay. Apoptosis status was assessed by caspase-3 activity detection. The pro-inflammatory cytokines (TNF-α and IL-18) were determined using ELISA assay. The association between miR-24-3p and BCL2L12 was confirmed by luciferase reporter assay.Results: We first observed that miR-24-3p expression level was lower in the OA cases than in the control patients and IL-1β decreased the expression of miR-24-3p in the chondrocyte CHON-001. Functionally, overexpression of miR-24-3p significantly attenuated IL-1β-induced chondrocyte injury, as reflected by increased cell viability, decreased caspase-3 activity, pro-inflammatory cytokines (TNF-α and IL-18). Western blot analysis showed that overexpression of miR-24-3p weakened IL-1β-induced cartilage degradation, as reflected by reduction of MMP13 (Matrix Metalloproteinase-13) and ADAMTS5 (A Disintegrin And Metalloproteinase with Thrombospondin Motifs-5) protein expression, as well as markedly elevation of COL2A1 (collagen type II). Importantly, BCL2L12 was demonstrated to be a target of miR-24-3p. BCL2L12 knockdown imitated, while overexpression significantly abrogated the protective effects of miR-24-3p against IL-1β-induced chondrocyte injury.Conclusions: In conclusion, our work provides important insight into targeting miR-24-3p/BCL2L12 axis in OA therapy.


Marine Drugs ◽  
2019 ◽  
Vol 17 (10) ◽  
pp. 552 ◽  
Author(s):  
Jiawen Zheng ◽  
Xiaoxiao Tian ◽  
Wen Zhang ◽  
Pingan Zheng ◽  
Fangfang Huang ◽  
...  

Fucoxanthin (Fx) is a natural extract from marine seaweed that has strong antioxidant activity and a variety of other bioactive effects. This study elucidated the protective mechanism of Fx on alcoholic liver injury. Administration of Fx was associated with lower pathological effects in liver tissue and lower serum marker concentrations for liver damage induced by alcohol. Fx also alleviated oxidative stress, and lowered the level of oxides and inflammation in liver tissue. Results indicate that Fx attenuated alcohol-induced oxidative lesions and inflammatory responses by activating the nuclear factor erythrocyte-2-related factor 2 (Nrf2)-mediated signaling pathway and down-regulating the expression of the toll-like receptor 4 (TLR4)-mediated nuclear factor-kappa B (NF-κB) signaling pathway, respectively. Our findings suggest that Fx can be developed as a potential nutraceutical for preventing alcohol-induced liver injury in the future.


2020 ◽  
Vol 12 (16) ◽  
pp. 1475-1487
Author(s):  
Linfu Li ◽  
Renbing Shi ◽  
Weimei Shi ◽  
Rui Zhang ◽  
Longhuo Wu

Oxysophocarpine (OSC) has been documented for anti-inflammatory activity. However, the mechanisms of OSC in anti-inflammation are unclear. Aim: To investigate the protective effects of OSC on inflammation and apoptosis induced by lipopolysaccharide in NCI-H292 and human primary airway epithelial cells. Materials & methods: MTT and Annexin V-FITC/PI staining were used to detect cells viability. Inflammatory responses were determined by ELISA. The quantitative real-time PCR (qRT-PCR) and western blot were used to detect mRNA/miRNA and protein expressions respectively. Co-immunoprecipitation was investigated for protein interactions. Results & conclusion: miR-155 mimics significantly induced cell apoptosis, inflammatory responses and MAPK and NF-κB pathways. NDFIP1 was identified as the target of miR-155. OSC protected cells against apoptosis and inflammatory responses and compromised miR-155 activity by attenuating MAPK and NF-κB pathways.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Li-juan Du ◽  
Bing Pang ◽  
Yu-meng Tan ◽  
Ya-nan Yang ◽  
Mei-zhen Zhang ◽  
...  

Background. Banxia Xiexin Decoction (BXXD) reportedly regulates glycolipid metabolism and inhibits pancreatic β-cell apoptosis. This study is aimed at investigating the protective effect of BXXD on tert-butyl hydroperoxide- (t-BHP-) induced apoptosis in MIN6 cells and the underlying mechanisms. Methods. MIN6 cells were preincubated with BXXD or liraglutide (Li) with or without PI3K inhibitor LY294002 (LY) for 12 h, following which t-BHP was added to induce MIN6 cell apoptosis. The protective effects of BXXD on MIN6 cells were evaluated by detecting cell viability and proliferation and glucose-stimulated insulin secretion (GSIS). The antiapoptotic effects were evaluated by Hoechst 33342 staining and terminal deoxynucleotidyl transferase dUTP nick end labeling assay (TUNEL). Malondialdehyde and glutathione peroxidase content and superoxide dismutase activity were measured using commercial kits. The expression of PI3K/AKT/FOXO1 signaling pathway-related signal molecules, and that of apoptotic indicators Bax, P27, and Caspase-3, was quantified using western blotting. Results. Preincubation with BXXD significantly improved t-BHP-induced proliferation inhibition and apoptosis and enhanced GSIS. t-BHP induced the generation of reactive oxygen species and inhibited the activities of antioxidant enzymes, which could be neutralized by pretreatment with BXXD. BXXD promoted the phosphorylation of AKT and FOXO1 in t-BHP-induced MIN6 cells. Moreover, BXXD attenuated the expression of related apoptotic indicators Bax, P27, and Caspase-3. LY abolished these effects of BXXD. Conclusion. BXXD protected MIN6 cells against t-BHP-induced apoptosis and improved insulin secretory function through modulation of the PI3K/AKT pathway and the downstream FOXO1, thus suggesting a novel therapeutic approach for type 2 diabetes mellitus (T2DM).


2016 ◽  
Vol 39 (4) ◽  
pp. 1453-1462 ◽  
Author(s):  
Feng Shan ◽  
Rui Yang ◽  
Tiemei Ji ◽  
Fengjun Jiao

Background/Aims: The study was aimed to investigate if vitamin C could exert protective effects on development of eryptosis caused by glucose-6-phosphate dehydrogenase (G6PD) deficiency and hydrogen peroxide. Methods: Isolated erythrocytes with different G6PD activity (normal or deficient) were divided into various groups treated by either Vitamin C or H2O2. Phosphatidylserine (PS) extroversion rate was detected by Annexin V binding. The intracellular Ca2+ concentration was detected by Fluo3-fluorescence, and western blot was used to detect the expression of apoptosis factor caspase 3. Results: Compared with the blank group, the PS extroversion rate (P < 0.001), intracellular Ca2+ concentration (P < 0.001) and active caspase 3 expression level (P < 0.05) of erythrocytes significantly increased after treatment of 0.05% H2O2. Then the index of eryptosis significantly decreased after erythrocytes were treated with Vitamin C (1 mg/ml) for 30 min (all P < 0.05). The decline in erythrocytes with G6PD normal activity was more significant than those with G6PD deficiency. Conclusion: Vitamin C could effectively inhibit the eryptosis contributed by H2O2 oxidative stress, and the suppression on eryptosis with G6PD normal activity was more effective than that with G6PD deficiency.


Sign in / Sign up

Export Citation Format

Share Document