scholarly journals IL-6/STAT3 Induced Neuron Apoptosis in Hypoxia by Downregulating ATF6 Expression

2021 ◽  
Vol 12 ◽  
Author(s):  
Simin Zhou ◽  
Zhifeng Zhong ◽  
Pei Huang ◽  
Bin Xiang ◽  
Xiaoxu Li ◽  
...  

Background: Neuron apoptosis, regulated by endoplasmic reticulum (ER) stress in the hippocampus, is an essential factor influencing the cognitive impairment induced by hypobaric hypoxia. Hypoxia mainly changes the activating transcription factor (ATF6) pathway of ER stress. However, the role of ATF6 in neuron survival, apoptosis, and upstream regulation is still controversial.Methods: We established a hypobaric hypoxia-induced C57BL/6 murine model and cell lines exposed to 1% hypoxia, including PC12 and HT22. First, we tested the expressions of interleukin 6 (IL-6), IL-1β, and IL-10 in C57BL/6 mice’s hippocampus under hypoxia using enzyme-linked immunosorbent assay (ELISA). We determined the signal transducer and activator of transcription 3 (STAT3) phosphorylation at tyrosine (Tyr)705 by western blot and the expression of ATF6, 78-kDa glucose-regulated protein (GRP78), and C/-EBP homologous protein (CHOP) related to ER stress by immunofluorescence (IF), western blot, and qRT-PCR; they were then verified on the cell model. Additionally, IL-6 (40 ng/mL) and STAT3 siRNA were used to treat the PC12 cells for 48 and 4 h to activate or silence STAT3, respectively. Subsequently, the cells of siRNA group were exposed to 1% hypoxia for 48 h. Furthermore, the ATF6 and CHOP expressions were detected with western blot and qRT-PCR. Finally, we examined the binding of STAT3 to the ATF6 promoter by chromatin immunoprecipitation (ChIP)-seq.Results: The results showed that IL-6 increased, IL-10 decreased in the hypoxia group, and IL-1β showed no difference between the hypoxia and the normoxia groups. Neuron apoptosis was significantly elevated by exposure to hypoxia for 48h in PC12 cells. The hypobaric hypoxia-induced ER stress proteins, ATF6, GRP78, and CHOP, and the p-STAT3 (Tyr705) expressions increased both in in vivo and in vitro. Besides, STAT3 silencing significantly promoted the ATF6 expression and inhibited CHOP, while STAT3 activation downregulated the expression of ATF6 and upregulated CHOP in PC12 cells. The ChIP-seq assay demonstrated that p-STAT3 (Tyr705) protein could bind to the ATF6 promoter region in HT22 cells.Conclusion: Phosphorylation of STAT3 at the Tyr705 site contributes to hypoxia-induced neuron apoptosis by downregulating ATF6, which might explain the inflammatory reaction and apoptosis of the hippocampal neurons induced by ER stress.

2020 ◽  
Vol 34 ◽  
pp. 205873842091000
Author(s):  
Shichun Wang ◽  
Qianqian Tang ◽  
Fuchao Ge ◽  
Qing Guo

This current research was performed to investigate the role of typhae pollen polysaccharides (TPP) in hypoxia-treated PC12 cell which was an in vitro cell model of cerebral ischemia. Hypoxia-treated cells were treated with TPP for 12 h. Cell viability and apoptosis were detected by 3-(4,5-dimethylthiazol-2-yl)-2 5-diphenyl-2H-tetrazolium bromide (MTT) assay and flow cytometry, respectively. Cell apoptotic proteins and PI3K/AKT and Ras/Raf/MEK/ERK signal pathway–associated proteins were also examined by western blot. Furthermore, abnormal expression of miR-34a and silent information regulator 1 (SIRT1) was achieved by transfection. Besides, the expression of miR-34a and SIRT1 was examined by quantitative real-time polymerase chain reaction (qRT-PCR). The expression of SIRT1 was detected by qRT-PCR and western blot. The relationship between miR-34a and SIRT1 was verified by luciferase assay. We found that TPP enhanced cell viability and inhibited apoptosis in hypoxia-treated PC12 cells. Moreover, TPP increased the accumulated levels of Bcl-2 while decreased expression of Bax, cleaved Caspase-3, and cleaved PARP. TPP downregulated miR-34a expression while induced by hypoxia. Further results showed that miR-34a overexpression reversed the results led by TPP in cell viability, apoptosis, and its related proteins. In addition, SIRT1 was upregulated by TPP and was verified to be a target of miR-34a. Silence of SIRT1 led to the opposite results led by TPP. In the end, TPP activated PI3K/AKT and Ras/Raf/MEK/ERK signal pathways. In conclusion, TPP plays important roles in regulating cell viability and apoptosis in hypoxia-treated PC12 cells via modulating miR-34a/SIRT1, as well as activating PI3K/AKT and Ras/Raf/MEK/ERK signal pathways.


2018 ◽  
Vol 46 (12) ◽  
pp. 5210-5218 ◽  
Author(s):  
Fang Wang ◽  
Jun Wang ◽  
Zhuo Zhang ◽  
Siwei Chen

Objective To investigate the effect of tetrandrine (Tet) on HaCaT cell proliferation and cytokine expression induced by interleukin (IL)-22, and to investigate the underlying mechanism. Methods The half maximal inhibitory concentration (IC50) and antiproliferation effects of Tet on IL-22-treated HaCaT cells were analysed by MTT assay. Signal transducer and activator of transcription 3 ( STAT3) expression was measured by reverse transcription plus real-time quantitative polymerase chain reaction (qPCR) and by Western blot. Phosphorylated (p)-STAT3 levels were also measured by Western blot. Cytokine production by HaCaT cells was analysed by enzyme-linked immunosorbent assay (ELISA) following administration of IL-22 and/or Tet. Results Tet displayed a dose-dependent inhibitory effect on HaCaT cell proliferation and reduced the phosphorylation level of STAT3 induced by IL-22, without affecting STAT3 mRNA and protein levels. Furthermore, co-incubation with Tet significantly down-regulated HaCaT cell production of tumour necrosis factor (TNF)-α, IL-1β, IL-6, IL-20 and chemokine (C-C motif) ligand 20 (CCL20) induced by IL-22. Conclusions Tet inhibits proliferation and cytokine production in HaCaT cells, and the process may involve the inhibition of STAT3 phosphorylation.


2021 ◽  
Vol 10 (7) ◽  
pp. 459-466
Author(s):  
Jie Yang ◽  
Yunping Zhou ◽  
Xiaojun Liang ◽  
Bingfei Jing ◽  
Zandong Zhao

Aims Osteoarthritis (OA) is characterized by persistent destruction of articular cartilage. It has been found that microRNAs (miRNAs) are closely related to the occurrence and development of OA. The purpose of the present study was to investigate the mechanism of miR-486 in the development and progression of OA. Methods The expression levels of miR-486 in cartilage were determined by quantitative real-time polymerase chain reaction (qRT-PCR). The expression of collagen, type II, alpha 1 (COL2A1), aggrecan (ACAN), matrix metalloproteinase (MMP)-13, and a disintegrin and metalloproteinase with thrombospondin motifs-4 (ADAMTS4) in SW1353 cells at both messenger RNA (mRNA) and protein levels was determined by qRT-PCR, western blot, and enzyme-linked immunosorbent assay (ELISA). Double luciferase reporter gene assay, qRT-PCR, and western blot assay were used to determine whether silencing information regulator 6 (SIRT6) was involved in miR-486 induction of chondrocyte-like cells to a more catabolic phenotype. Results Compared with osteonecrosis, the expression of miR-486 was significantly upregulated in cartilage from subjects with severe OA. In addition, overexpressed miR-486 promoted a catabolic phenotype in SW1353 cells by upregulating the expressions of ADAMTS4 and MMP-13 and down-regulating the expressions of COL2A1 and ACAN. Conversely, inhibition of miR-486 had the opposite effect. Furthermore, overexpression of miR-486 significantly inhibited the expression of SIRT6, confirming that SIRT6 is a direct target of miR-486. Moreover, SW1353 cells were transfected with small interfering RNA (si)-SIRT6 and it was found that SIRT6 was involved in and inhibited miR-486-induced changes to SW1353 gene expression. Conclusion Our results indicate that miR-486 promotes a catabolic phenotype in SW1353 cells in OA by targeting SIRT6. Our findings might provide a potential therapeutic target and theoretical basis for OA. Cite this article: Bone Joint Res 2021;10(7):459–466.


Zygote ◽  
2021 ◽  
pp. 1-7
Author(s):  
Mengyuan Xie ◽  
Dong Han ◽  
Xiaojing Xu

Summary To study the role of orexin A in the reproductive regulation of Mongolian sheep, ovine ovarian granulosa cells were cultured in vitro. The cells were divided into groups after luteinization, the experimental group was given orexin A and the transcriptome was sequenced together with that of the control group. The different genes related to reproduction were screened out. qRT-PCR, western blot and enzyme-linked immunosorbent assay (ELISA) were used to verify the selected genes and detect the effect on progesterone secretion. In total, 123 differentially expressed genes were obtained by sequencing. Six genes with high expression related to reproduction (PRRT2, ABCG1, SOX4, TBX3, ID1 and ATP8) were screened. The results of qRT-PCR were consistent with those of sequencing; western blot and ELISA were used to verify the protein levels of steroidogenic acute regulatory protein (StAR) and its related PRRT2 and ABCG1, and to detect their effect on progesterone secretion. Validation results were consistent with those of qRT-PCR and sequencing. The experimental group was given orexin A and compared with the control group. Expression of PRRT2 protein was significantly increased (P < 0.05), ABCG1 protein expression was significantly decreased (P < 0.05), StAR expression was significantly increased (P < 0.05), and progesterone secretion was significantly increased (P < 0.05). The results showed that orexin A promoted the expression of StAR by upregulating PRRT2 and downregulating ABCG1, therefore affecting secretion of progesterone. Gene expression characteristics of orexin A affecting progesterone secretion were preliminarily explored; this study provides a theoretical basis for further study on signalling pathways and reproductive regulation in Mongolian sheep.


2021 ◽  
Author(s):  
Ting Ye ◽  
Wei-ting Xuan ◽  
Peng Zhou ◽  
Nan Shao ◽  
Hang Song ◽  
...  

Abstract Background Huangdi Anxiao (HDAX) is mainly used to treat diabetes and its complications for many years and has a remarkable curative effect. However, the improvement effect of HDAX in the diabetic cognitive dysfunction (DCD) model and the related mechanism is not clear. This study was aimed to explore the neuroprotective effects of HDAX and its possible mechanisms in DCD. Methods A DCD cell model was established by high glucose-induced PC12 cells, and the effect of HDAX on the cell viability was examined by MTT. Additionally, the expression of relevant genes and proteins in the apoptosis pathway of endoplasmic reticulum (ER) stress was detected. Results The results showed that HDAX increased cell viability, reduced GRP78, CHOP, Bax, procaspase-12, procaspase-9, procaspase-3 mRNA levels and GRP78, CHOP, Bax, Caspase-12, Caspase-9, Caspase-3 protein expressions, and decreased Bcl-2 mRNA level and protein expression. Conclusions These results suggested that HDAX had neuroprotective effects in the DCD cell model, which may be associated with the inhibition of the apoptosis pathway of ER stress.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yuequan Zhao ◽  
YunPeng Tian ◽  
Tao Feng

Objective. Our research is designed to explore the function of sodium houttuyfonate (SH) on Alzheimer’s disease (AD) and its potential molecular mechanisms. Methods. In our study, the Morris water maze (MWM) test was used to assess the role of SH on spatial learning and memory deficiency in amyloid-β peptide (Aβ)1-42-induced AD mice. We explored the functions of SH on proinflammatory cytokines, neuron apoptosis, and damage in vivo and in vitro by using an enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction (qRT-PCR), flow cytometry, western blot, and Nissl staining. Moreover, the effect of SH on oxidative stress in vivo and in vitro was also detected. To explore the underlying molecular mechanisms of SH on AD, the expressions of proteins and mRNA involved in the NOD-like receptor pyrin domain containing-3/gasdermin D (NLRP3/GSDMD) pathway were determined using western blot, immunofluorescence staining, and qRT-PCR. Results. Our data demonstrated that SH ameliorated spatial learning and memory deficiency in Aβ1-42-induced AD mice. Moreover, SH significantly improved hippocampal neuron damage and inhibited oxidative stress, neuroinflammation, and neuron apoptosis in Aβ1-42-induced AD mice and PC12 cells. The results also revealed that SH protected Aβ1-42-induced AD through inhibiting the NLRP3/GSDMD pathway. Conclusion. The present study demonstrated that SH could ameliorate Aβ1-42-induced memory impairment neuroinflammation and pyroptosis through inhibiting the NLRP3/GSDMD pathway in AD, suggesting that SH may be a potential candidate for AD treatment.


2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Hong-Xing Liao ◽  
Zhi-Hui Zhang ◽  
Hui-Lin Chen ◽  
Ying-Mei Huang ◽  
Zhan-Liang Liu ◽  
...  

Abstract Background Hyaluronan (HA) metabolism by chondrocytes is important for cartilage development and homeostasis. However, information about the function of circular RNAs (circRNAs) in HA metabolism is limited. We therefore profiled the role of the novel HA-related circRNA circHYBID in the progression of osteoarthritis (OA). Methods CircHYBID function in HA metabolism in chondrocytes was investigated using gain-of-function experiments, and circHYBID mechanism was confirmed via bioinformatics analysis and luciferase assays. The expression of circHYBID–hsa-miR-29b-3p–transforming growth factor (TGF)-β1 axis was examined by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. CircHYBID, TGF-β1, and HA levels in cartilage samples were evaluated using qRT-PCR and pathological examination. Enzyme-linked immunosorbent assay was used to assess HA accumulation in chondrocyte supernatant. Results CircHYBID expression was significantly downregulated in damaged cartilage samples compared with that in the corresponding intact cartilage samples. CircHYBID expression was positively correlated with alcian blue score. Interleukin-1β stimulation in chondrocytes downregulated circHYBID expression and decreased HA accumulation. Gain-of-function experiments revealed that circHYBID overexpression in chondrocytes increased HA accumulation by regulating HA synthase 2 and HYBID expression. Further mechanism analysis showed that circHYBID upregulated TGF-β1 expression by sponging hsa-miR-29b-3p. Conclusions Our results describe a novel HA-related circRNA that could promote HA synthesis and accumulation. The circHYBID–hsa-miR-29b-3p–TGF-β1 axis may play a powerful regulatory role in HA metabolism and OA progression. Thus, these findings will provide new perspectives for studies on OA pathogenesis, and circHYBID may serve as a potential target for OA therapy.


2021 ◽  
pp. 1-8
Author(s):  
Tiange Wu ◽  
Xiaoning Wang ◽  
Kai Ren ◽  
Xiaochen Huang ◽  
Jiankai Liu

Introduction: The aim of this study was to investigate the modified proteins in methylene blue/light-treated frozen plasma (MB-FP) compared with fresh frozen plasma (FFP) in order to gain a better application of MB/light-treated plasma in clinic transfusion. Methods: MB-FP and FFP were collected from Changchun central blood station, and a trichloroacetic acid/acetone precipitation method was used to remove albumin for the enrichment of lower abundance proteins. The plasma protein in MB-FP and FFP were separated using two-dimensional gel electrophoresis (2-DE) and the differentially expressed protein spots were analyzed using mass spectrometry. Finally, the differentially expressed proteins were tested using Western blot and enzyme-linked immunosorbent assay (ELISA). Results: Approximately 14 differentially expressed protein spots were detected in the MB-FP, and FFP was chosen as the control. After 2-DE comparison analysis and mass spectrometry, 8 significantly differentially expressed protein spots were identified, corresponding to 6 different proteins, including complement C1r subcomponent (C1R), inter-alpha-trypsin inhibitor heavy chain H4 (ITI-H4), keratin, type II cytoskeletal 1 (KRT1), hemopexin (HPX), fibrinogen gamma chain (FGG), and transthyretin (TTR). Western blot showed no significant difference in the expression level of KRT1 between MB-FP and FFP (p > 0.05). Both Western blot and ELISA indicated that the level of HPX was significantly higher in FFP than in MB-FP (p < 0.05). Conclusion: This comparative proteomics study revealed that some significantly modified proteins occur in MB-FP, such as C1R, ITI-H4, KRT1, HPX, FGG, and TTR. Our findings provide more theoretical data for using MB-FP in transfusion medicine. However, the relevance of the data for the transfusion of methylene blue/light-treated plasma remains unclear. The exact modification of these proteins and the effects of these modified proteins on their functions and their effects in clinical plasma infusion need to be further studied.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Xu Gao ◽  
Jingya Dai ◽  
Guifang Li ◽  
Xinya Dai

Abstract Objective In this work, we investigated the effects of gambogic acid (GA) on lipopolysaccharide (LPS)-induced apoptosis and inflammation in a cell model of neonatal pneumonia. Method Human WI-38 cells were maintained in vitro and incubated with various concentrations of GA to examine WI-38 survival. GA-preincubated WI-38 cells were then treated with LPS to investigate the protective effects of GA on LPS-induced death, apoptosis and inflammation. Western blot assay was utilized to analyze the effect of GA on tropomyosin receptor kinase A (TrkA) signaling pathway in LPS-treated WI-38 cells. In addition, human AKT serine/threonine kinase 1 (Akt) gene was knocked down in WI-38 cells to further investigate the associated genetic mechanisms of GA in protecting LPS-induced inflammation and apoptosis. Results Pre-incubating WI-38 cells with low and medium concentrations GA protected LPS-induced cell death, apoptosis and inflammatory protein productions of IL-6 and MCP-1. Using western blot assay, it was demonstrated that GA promoted TrkA phosphorylation and Akt activation in LPS-treated WI-38 cells. Knocking down Akt gene in WI-38 cells showed that GA-associated protections against LPS-induced apoptosis and inflammation were significantly reduced. Conclusions GA protected LPS-induced apoptosis and inflammation, possibly through the activations of TrkA and Akt signaling pathway. This work may broaden our understanding on the molecular mechanisms of human neonatal pneumonia.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yuhua Su ◽  
Yajing Liu ◽  
Chao Ma ◽  
Chunxiao Guan ◽  
Xiufen Ma ◽  
...  

Abstract Background Long non-coding RNA heart and neural crest derivatives expressed 2-antisense RNA 1 (HAND2-AS1) was found to be elevated in rheumatoid arthritis (RA) fibroblast-like synoviocytes (RA-FLSs). However, whether HAND2-AS1 functions as an exosomal lncRNA related to mesenchymal stem cells (MSCs) in RA progression is unknown. Methods The expression of HAND2-AS1, microRNA (miR)-143-3p, and tumor necrosis factor alpha-inducible protein 3 (TNFAIP3) was detected using quantitative real-time polymerase chain reaction and Western blot. Cell proliferation, apoptosis, migration, and invasion were detected using cell counting kit-8, flow cytometry, and wound healing and transwell assays. The levels of tumor necrosis factor-α (TNF-α) and interleukins (IL)-6 were analyzed using enzyme-linked immunosorbent assay. The level of phosphorylated-p65 was examined by Western blot. The binding interaction between miR-143-3p and HAND2-AS1 or TNFAIP3 was confirmed by the dual-luciferase reporter and RIP assays. Exosomes were isolated by ultracentrifugation and qualified by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and Western blot. Results HAND2-AS1 was lowly expressed in RA synovial tissues, and HAND2-AS1 re-expression suppressed the proliferation, motility, and inflammation and triggered the apoptosis in RA-FLSs via the inactivation of NF-κB pathway. Mechanistically, HAND2-AS1 directly sponged miR-143-3p and positively regulated TNFAIP3 expression, the target of miR-143-3p. Moreover, the effects of HAND2-AS1 on RA-FLSs were partially attenuated by miR-143-3p upregulation or TNFAIP3 knockdown. HAND2-AS1 could be packaged into hMSC-derived exosomes and absorbed by RA-FLSs, and human MSC-derived exosomal HAND2-AS1 also repressed above malignant biological behavior of RA-FLSs. Conclusion MSC-derived exosomes participated in the intercellular transfer of HAND2-AS1 and suppressed the activation of RA-FLSs via miR-143-3p/TNFAIP3/NF-κB pathway, which provided a novel insight into the pathogenesis and treatment of RA.


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