scholarly journals MACROD1/LRP16 Enhances LPS-Stimulated Inflammatory Responses by Up-Regulating a Rac1-Dependent Pathway in Adipocytes

2018 ◽  
Vol 51 (6) ◽  
pp. 2591-2603 ◽  
Author(s):  
Li Zang ◽  
Quan Hong ◽  
Guoqing Yang ◽  
Weijun Gu ◽  
Anping Wang ◽  
...  

Background/Aims: Chronic inflammation contributes to the development of type 2 diabetes mellitus by targeting the insulin receptor substrate protein-1 (IRS-1) signaling pathway. Previous studies showed that Leukemia related protein 16 (LRP16) reduced insulin stimulated glucose uptake in adipocytes by impairing the IRS-1 signaling pathway. We explored the mechanism by which LRP16 promotes the inflammatory response. Methods: We screened LRP16 induced proteins in the lipopolysaccharide (LPS)-stimulated inflammatory response using liquid chromatography-mass spectrometry (LC-MS) and analyzed the potential biological functions of these proteins using online bioinformatics tools. mRNA expression and protein expression of target genes were measured by real time PCR and Western blot, respectively. Results: A total of 390 differentially expressed proteins were identified. The mitogen-activated protein kinase (MAPK) signaling pathway was the primary activated pathway in LRP16-expressing cells. Overexpression of LRP16 activated ERK1/2 and Rac1, which are two key players related to the MAPK signaling pathway. Furthermore, knock down of endogenous LRP16 by RNA interference (RNAi) reduced Rac1 expression, ERK activation, and inflammatory cytokine expression in human adipocytes stimulated by LPS. The stimulatory effect of LRP16 was diminished by suppressing Rac1 expression and treating the cells with the ERK specific inhibitor, PD98059. Conclusion: These findings revealed the functions of LRP16 in promoting the inflammatory response through activating the Rac1-MAPK1/ERK pathway in human adipocytes.

2021 ◽  
Vol 49 (5) ◽  
pp. 56-62
Author(s):  
Hongtao Chen ◽  
Li Zhang

Background and objective: Osteoarthritis is the most common chronic osteoarthrosis disease. There are complex factors that lead to osteoarthritis. Therefore, it is essential to investigate the molecular mechanism of osteoarthritis, especially the mechanism of articular cartilage degeneration. In this study, the mechanism of FPR1 (formyl peptide receptor 1) in LPS (lipopolysaccharide) induced chondrogenic cell ATDC5 was investigated.Materials and methods: We employed real-time quantitative polymerase chain reaction (RT-qPCR) and western blot assay to analyze the expression level of FPR1 in ATDC5 cell linesinduced by LPS at 0, 2.5, 5, and 10 μg/mL concentrations. Then we constructed the FPR1 knockdown plasmid to transfect the LPS-ATDC5. MTT assay was used to test cell viability in control, LPS, LPS+shNC and LPS+shFPR1 groups. ELISA and RT-qPCR assay were employed to examine the TNF-α (tumor necrosis factor-α)、IL-6 and IL-1β expression level. Flow cytometry and western blot assay were employed to analyze the apoptosis of LPS-ATDC5. Finally, we utilized the western blot assay to text related protein expression level of MAPK (mitogen-activated protein kinase) signaling pathway.Results: In this study, we found the expression level of FPR1 was increased in LPS-ATDC5, downregulation of FPR1 improves the survival rate and alleviates inflammatory response of LPS-ATDC5. Meanwhile, downregulation of FPR1 alleviates apoptosis of LPS-ATDC5. Finally, downregulation of FPR1 inhibits the MAPK signal pathway.Conclusion: Present study revealed that FPR1 was highly expressed in LPS-induced chondrocytes ATDC5, and the downregulation of FPR1 abated the inflammatory response and apoptosis of LPS-ATDC5 cells by regulating the MAPK signaling pathway.


2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Li Li ◽  
Huabo Jiang ◽  
Xuecong Wei ◽  
Dandan Geng ◽  
Ming He ◽  
...  

Vascular endothelial growth factor receptor-2 (VEGFR-2) regulates the mitogen-activated protein kinase (MAPK) signaling pathway and plays an important role in angiogenesis. Bu Shen Zhu Yun decoction (BSZYD) can improve endometrial receptivity and embryo implantation rates in patients undergoing in vitro fertilization. However, whether BSZYD improves endometrial receptivity via angiogenesis remains unclear. Here, we investigated the effects of BSZYD on the proliferation, migration, and angiogenesis of human endometrial microvascular endothelial cells (HEMECs) and found that BSZYD upregulated the expression of cyclin D1, matrix metalloproteinase 9 (MMP9), and proliferating cell nuclear antigen (PCNA) in HEMECs. Cell Counting Kit 8 assay, scratch-wound assay, and Tube Formation Assay results showed that BSZYD promoted the proliferation, migration, and angiogenesis of HEMECs. Western blot analysis results revealed the activation of the MAPK signaling pathway by BSZYD through the upregulation of VEGF and VEGFR-2 expression. Together, these findings highlight the novel mechanism underlying BSZYD-mediated improvement in endometrial receptivity through the MAPK signaling pathway.


2020 ◽  
Author(s):  
Jing-Shuai Wu ◽  
Qin-Yu Meng ◽  
Xiao-Hui Shi ◽  
Zhen-Kun Zhang ◽  
Hua-Shi Guan ◽  
...  

Abstract Background: Neuroinflammatory processes are critical in the development and progression of Alzheimer's disease (AD). The potent anti-neuroinflammatory inhibitors are expected as the candidates to treat AD. Cryptotanshinone (1), a major bioactive constituent in the traditional Chinese medicinal herb Dan-Shen Salvia miltiorrhiza Bunge, has been reported to possess remarkable pharmacological activities, especially anti-oxidation and anti-inflammation. Methods: Cryptotanshinone (1) was biotransformed with the fungus Cunninghamella elegans AS3.2028 to improve its bioactivities and physicochemical properties. The structures of transformed products were elucidated by comprehensive spectroscopic analysis including HRESIMS, NMR and ECD data. Their anti-neuroinflammatory activities were assessed by ELISA, transcriptome analysis, western blot, and immunofluorescence methods. Results: Three oxygenated products (2–4) at C-3 of cryptotanshinone (1) were obtained, among them 2 was a new compound. All of the biotransformed products (2–4) were found to inhibit significantly lipopolysaccharide-induced nitric oxide production in BV2 microglia cells with the IC50 values of 0.16‒1.16 μM, approximately 2‒20 folds stronger than the substrate (1). These biotransformed products also displayed remarkably improved inhibitory effects on the production of inflammatory cytokines (IL-1β, IL-6, TNF-α, COX-2 and iNOS) in BV-2 cells via targeting TLR4 compared to substrate (1). The underlying mechanism of 2 was elucidated by comparative transcriptome analysis, which suggested that it reduced neuroinflammatory mainly through mitogen-activated protein kinase (MAPK) signaling pathway. Western blotting results revealed that 2 downregulated LPS-induced phosphorylation of JNK, ERK, and p38 in MAPK signaling pathway. Conclusion: The biotransformed products of cryptotanshinone exhibit potent anti-neuroinflammatory activities. These findings provide a basal material for the discovery of candidates in treating AD.


2021 ◽  
Author(s):  
Jingjing Fan ◽  
Sitong Liu ◽  
Zhiyi Ai ◽  
Yiying Chen ◽  
Yonghong Wang ◽  
...  

Generally, ginsenosides have the physiological effect of an anti-inflammatory immunity.


2020 ◽  
Vol 21 (9) ◽  
pp. 3236 ◽  
Author(s):  
Karel Vališ ◽  
Petr Novák

Extracellular signal-regulated kinase (ERK) is a part of the mitogen-activated protein kinase (MAPK) signaling pathway which allows the transduction of various cellular signals to final effectors and regulation of elementary cellular processes. Deregulation of the MAPK signaling occurs under many pathological conditions including neurodegenerative disorders, metabolic syndromes and cancers. Targeted inhibition of individual kinases of the MAPK signaling pathway using synthetic compounds represents a promising way to effective anti-cancer therapy. Cross-talk of the MAPK signaling pathway with other proteins and signaling pathways have a crucial impact on clinical outcomes of targeted therapies and plays important role during development of drug resistance in cancers. We discuss cross-talk of the MAPK/ERK signaling pathway with other signaling pathways, in particular interplay with the Hippo/MST pathway. We demonstrate the mechanism of cell death induction shared between MAPK/ERK and Hippo/MST signaling pathways and discuss the potential of combination targeting of these pathways in the development of more effective anti-cancer therapies.


Author(s):  
Yehong Du ◽  
Yexiang Du ◽  
Yun Zhang ◽  
Zhilin Huang ◽  
Min Fu ◽  
...  

AbstractMitogen-activated protein kinase (MAPK) phosphatase 1 (MKP-1) is an essential negative regulator of MAPKs by dephosphorylating MAPKs at both tyrosine and threonine residues. Dysregulation of the MAPK signaling pathway has been associated with Alzheimer’s disease (AD). However, the role of MKP-1 in AD pathogenesis remains elusive. Here, we report that MKP-1 levels were decreased in the brain tissues of patients with AD and an AD mouse model. The reduction in MKP-1 gene expression appeared to be a result of transcriptional inhibition via transcription factor specificity protein 1 (Sp1) cis-acting binding elements in the MKP-1 gene promoter. Amyloid-β (Aβ)-induced Sp1 activation decreased MKP-1 expression. However, upregulation of MKP-1 inhibited the expression of both Aβ precursor protein (APP) and β-site APP-cleaving enzyme 1 by inactivating the extracellular signal-regulated kinase 1/2 (ERK)/MAPK signaling pathway. Furthermore, upregulation of MKP-1 reduced Aβ production and plaque formation and improved hippocampal long-term potentiation (LTP) and cognitive deficits in APP/PS1 transgenic mice. Our results demonstrate that MKP-1 impairment facilitates the pathogenesis of AD, whereas upregulation of MKP-1 plays a neuroprotective role to reduce Alzheimer-related phenotypes. Thus, this study suggests that MKP-1 is a novel molecule for AD treatment.


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