scholarly journals Differential Cytokine-Induced Responses of Polarized Microglia

2021 ◽  
Vol 11 (11) ◽  
pp. 1482
Author(s):  
Priyanka Chauhan ◽  
Wen S. Sheng ◽  
Shuxian Hu ◽  
Sujata Prasad ◽  
James R. Lokensgard

The role of select pro- and anti-inflammatory mediators in driving microglial cell polarization into classically (M1), or alternatively, (M2) activated states, as well as the subsequent differential responses of these induced phenotypes, was examined. Expression of PD-L1, MHC-II, MHC-I, arginase 1 (Arg-1), and inducible nitric oxide synthase (iNOS) was assessed using multi-color flow cytometry. We observed that both pro- and anti-inflammatory mediators induced PD-L1 expression on non-polarized microglia. Moreover, IFN-γ stimulated significant MHC class I and II expression on these cells. Interestingly, we observed that only IL-4 treatment induced Arg-1 expression, indicating M2 polarization. These M2 cells were refractory to subsequent depolarization and maintained their alternatively activated state. Furthermore, PD-L1 expression was significantly induced on these M2-polarized microglia after treatment with pro-inflammatory mediators, but not anti-inflammatory cytokines. In addition, we observed that only LPS induced iNOS expression in microglial cells, indicating M1 polarization. Furthermore, IFN-γ significantly increased the percentage of M1-polarized microglia expressing iNOS. Surprisingly, when these M1-polarized microglia were treated with either IL-6 or other anti-inflammatory cytokines, they returned to their non-polarized state, as demonstrated by significantly reduced expression of iNOS. Taken together, these results demonstrate differential responses of microglial cells to mediators present in dissimilar microenvironments.

2019 ◽  
Vol 16 (3) ◽  
pp. 251-260 ◽  
Author(s):  
Elaine Wan Ling Chan ◽  
Emilia Tze Ying Yeo ◽  
Kelly Wang Ling Wong ◽  
Mun Ling See ◽  
Ka Yan Wong ◽  
...  

<P>Background: Alzheimer’s disease (AD) is a multifactorial neurodegenerative disorder that eventually leads to severe cognitive impairment. Although the exact etiologies of AD still remain elusive, increasing evidence suggests that neuroinflammation cascades mediated by microglial cells are associated with AD. Piper sarmentosum Roxb. (PS) is a medicinal plant reported to possess various biological properties, including anti-inflammatory, anti-psychotic and anti-oxidant activity. However, little is known about the anti-inflammatory activity of PS roots despite their traditional use to treat inflammatory- mediated ailments. Objective: This study aimed to evaluate the anti-inflammatory and neuroprotective properties of extracts obtained from the roots of PS against beta-amyloid (Aβ)-induced microglial toxicity associated with the production of pro-inflammatory mediators. Method: BV2 microglial cells were treated with hexane (RHXN), dichloromethane (RDCM), ethyl acetate (REA) and methanol (RMEOH) extracts of the roots of PS prior to activation by Aβ. The production and mRNA expression of pro-inflammatory mediators were evaluated by Griess reagent, ELISA kits and RT-qPCR respectively. The phosphorylation status of p38α MAPK was determined via western blot assay. BV2 conditioned medium was used to treat SH-SY5Y neuroblastoma cells and the neuroprotective effect was assessed using MTT assay. Results: PS root extracts, in particular RMEOH significantly attenuated the production and mRNA expression of IL-1β, IL-6 and TNF-α in Aβ-induced BV2 microglial cells. In addition, RHXN, REA and RMEOH extracts significantly reduced nitric oxide (NO) level and the inhibition of NO production was correlated with the total phenolic content of the extracts. Further mechanistic studies suggested that PS root extracts attenuated the production of cytokines by regulating the phosphorylation of p38α MAPK in microglia. Importantly, PS root extracts have protective effects against Aβ-induced indirect neurotoxicity either by inhibiting the production of NO, IL-1β, IL-6, and TNF-α in BV2 cells or by protecting SHSY5Y cells against these inflammatory mediators. Conclusions: These findings provided evidence that PS root extracts confer neuroprotection against Aβ- induced microglial toxicity associated with the production of pro-inflammatory mediators and may be a potential therapeutic agent for inflammation-related neurological conditions including Alzheimer’s disease (AD).</P>


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shengchao Zhang ◽  
Jiankai Fang ◽  
Zhanhong Liu ◽  
Pengbo Hou ◽  
Lijuan Cao ◽  
...  

Abstract Background Muscle stem cells (MuSCs) are absolutely required for the formation, repair, and regeneration of skeletal muscle tissue. Increasing evidence demonstrated that tissue stem cells, especially mesenchymal stem cells (MSCs), can exert therapeutic effects on various degenerative and inflammatory disorders based on their immunoregulatory properties. Human mesenchymal stem cells (hMSCs) treated with interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) were reported to possess anti-inflammatory functions by producing TNF-stimulated gene 6 (TSG-6). However, whether human muscle stem cells (hMuSCs) also possess TSG-6 mediated anti-inflammatory functions has not been explored. Methods The ulcerative colitis mouse model was established by subjecting mice to dextran sulfate sodium (DSS) in drinking water for 7 days. hMuSCs were pretreated with IFN-γ and TNF-α for 48 h and were then transplanted intravenously at day 2 of DSS administration. Body weights were monitored daily. Indoleamine 2,3-dioxygenase (IDO) and TSG-6 in hMuSCs were knocked down with short hairpin RNA (shRNA) and small interfering RNA (siRNA), respectively. Colon tissues were collected for length measurement and histopathological examination. The serum level of IL-6 in mice was measured by enzyme-linked immunosorbent assay (ELISA). Real-time PCR and Western blot analysis were performed to evaluate gene expression. Results hMuSCs treated with inflammatory factors significantly ameliorated inflammatory bowel disease (IBD) symptoms. IDO and TSG-6 were greatly upregulated and required for the beneficial effects of hMuSCs on IBD. Mechanistically, the tryptophan metabolites, kynurenine (KYN) or kynurenic acid (KYNA) produced by IDO, augmented the expression of TSG-6 through activating their common receptor aryl hydrocarbon receptor (AHR). Conclusion Inflammatory cytokines-treated hMuSCs can alleviate DSS-induced colitis through IDO-mediated TSG-6 production.


2014 ◽  
Vol 42 (04) ◽  
pp. 891-904 ◽  
Author(s):  
Mi Young Song ◽  
Hyo Won Jung ◽  
Seok Yong Kang ◽  
Kyung-Ho Kim ◽  
Yong-Ki Park

The root bark of Lycium barbarum (Lycii radicis cortex, LRC) is used as a cooling agent for fever and night sweats in East Asian traditional medicine. The inhibitory effect of LRC water extract on inflammation is unknown. In this study, the anti-inflammatory effect of LRC was investigated in lipopolysaccharide (LPS)-stimulated mouse macrophage, RAW 264.7 cells. LRC extract significantly decreased the LPS-induced production of inflammatory mediators, nitric oxide (NO), prostaglandin (PG) E2 and pro-inflammatory cytokines, interleukin (IL)-1β and IL-6 in the cells. In addition, LRC extract inhibited the LPS-induced expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 mRNA and protein, and inflammatory cytokines mRNA in the cells. The action mechanism of LRC underlies the blocking of LPS-mediated p38 and Jun N-terminal kinase (JNK), mitogen-activated protein kinases (MAPKs), and the nuclear factor (NF)-κB signaling pathway. These results indicate that LRC extract inhibits the inflammatory response in activated macrophages by down-regulating the transcription levels of inflammatory mediators and blocking the MAPKs and NF-κB pathway.


Author(s):  
Tae-Young Gil ◽  
Bo-Ram Jin ◽  
Chul-Hee Hong ◽  
Jong Hyuk Park ◽  
Hyo-Jin An

Abstract Background Macrophages play a crucial role in inflammation. Astilbe chinensis is one of perennial herbs belonging to the genus Astilbe. Plants in the genus have been used for pain, headaches, arthralgia, and chronic bronchitis. However, the effect of A.chinensis on inflammation remains unclear. To study the anti-inflammatory action of A.chinensis ethanol extract (ACE), we investigated the effect of ACE on the production of pro-inflammatory mediators and cytokines in macrophages. Methods We evaluated the effectiveness of ACE in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and thioglycollate (TG)-elicited peritoneal macrophages from male C57BL/6 mice. We measured the levels of pro-inflammatory mediators and cytokines, and examined the anti-inflammatory actions of ACE on nuclear factor κB (NF-κB) pathway in the macrophages. Western blot analysis and immunofluorescence microscopy were used to determine protein level and translocation, respectively. Results ACE suppressed the output of nitric oxide (NO), prostaglandin E2 (PGE2), and pro-inflammatory cytokines in stimulated macrophages via inhibiting the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins. ACE suppressed mRNA expression of pro-inflammatory cytokines such as interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-α). We examined the efficacies of ACE on NF-κB activation by measuring the expressions including IκB kinase (IKK), inhibitor of κB (IκB), and nuclear p65 proteins. In addition, the inhibition of NF-κB p65’s translocation was determined with immunofluorescence assay. Conclusion Our findings manifested that ACE inhibited LPS or TG-induced inflammation by blocking the NF-κB signaling pathway in macrophages. It indicated that ACE is a potential therapeutic mean for inflammation and related diseases.


Author(s):  
Bruna Lima Correa ◽  
Nadia El Harane ◽  
Ingrid Gomez ◽  
Hocine Rachid Hocine ◽  
José Vilar ◽  
...  

Abstract Aims The cardioprotective effects of human induced pluripotent stem cell-derived cardiovascular progenitor cells (CPC) are largely mediated by the paracrine release of extracellular vesicles (EV). We aimed to assess the immunological behaviour of EV-CPC, which is a prerequisite for their clinical translation. Methods and results Flow cytometry demonstrated that EV-CPC expressed very low levels of immune relevant molecules including HLA Class I, CD80, CD274 (PD-L1), and CD275 (ICOS-L); and moderate levels of ligands of the natural killer (NK) cell activating receptor, NKG2D. In mixed lymphocyte reactions, EV-CPC neither induced nor modulated adaptive allogeneic T cell immune responses. They also failed to induce NK cell degranulation, even at high concentrations. These in vitro effects were confirmed in vivo as repeated injections of EV-CPC did not stimulate production of immunoglobulins or affect the interferon (IFN)-γ responses from primed splenocytes. In a mouse model of chronic heart failure, intra-myocardial injections of EV-CPC, 3 weeks after myocardial infarction, decreased both the number of cardiac pro-inflammatory Ly6Chigh monocytes and circulating levels of pro-inflammatory cytokines (IL-1α, TNF-α, and IFN-γ). In a model of acute infarction, direct cardiac injection of EV-CPC 2 days after infarction reduced pro-inflammatory macrophages, Ly6Chigh monocytes, and neutrophils in heart tissue as compared to controls. EV-CPC also reduced levels of pro-inflammatory cytokines IL-1α, IL-2, and IL-6, and increased levels of the anti-inflammatory cytokine IL-10. These effects on human macrophages and monocytes were reproduced in vitro; EV-CPC reduced the number of pro-inflammatory monocytes and M1 macrophages, while increasing the number of anti-inflammatory M2 macrophages. Conclusions EV-CPC do not trigger an immune response either in in vitro human allogeneic models or in immunocompetent animal models. The capacity for orienting the response of monocyte/macrophages towards resolution of inflammation strengthens the clinical attractiveness of EV-CPC as an acellular therapy for cardiac repair.


2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 17-19
Author(s):  
Shuhui Li

Abstract Lipocalin 2 (Lcn2) is an essential component of the innate immune system and exerts significant immunomodulatory effects in vitro. The aim of current study was to investigate the expression profile of Lcn2 during inflammatory process and explore the role of Lcn2 in the anti-inflammatory responses. Western blot, real-time quantitative PCR, immunofluorescence (IF) and enzyme-linked immunosorbent assay (ELISA) were employed. Firstly, we evaluated the temporospatial expression of Lcn2 of mice after inflammatory stimuli by lipopolysaccharides (LPS). In vivo, LPS induced both mRNA and protein levels of Lcn2 significantly (P &lt; 0.01) in liver, jejunum and ileum. Lcn2 exhibited a continuous increase by 8 h and peaked by 24 h post challenges. Secondly, we challenged Lcn2-deficient (Lcn2-/-) mice and wild-type (WT) mice with peripheral LPS and determined effects on inflammation. In contrast to WT mice, Lcn2-/- mice showed distinct inflammatory injury in liver, jejunum, ileum and spleen with significantly elevated pro-inflammatory cytokines interleukin-6 (IL-6) and interleukin-1b (IL-1b) and decreased anti-inflammatory cytokine interleukin-10 (IL-10). Thirdly, we isolated bone marrow-derived macrophages (BMDM) from Lcn2-/- mice and WT mice to evaluate their functions. After LPS challenge, Lcn2-/- BMDM showed aggravated inflammatory reaction as pro-inflammatory factors tumour necrosis factor-α (TNF-α), IL-6, IL-1b and inducible nitric oxide synthase (iNOS) increased (P &lt; 0.05) while anti-inflammatory cytokines IL-10, transforming growth factor β1 (TGF-β1) and arginase-1(Arg-1) decreased significantly (P &lt; 0.05) compared with WT BMDM. This phenomenon could be relieved when adding recombinant Lcn2 (P &lt; 0.05). The exogenous addition of Lcn2 on mice RAW264.7 macrophages stimulated by LPS also conformed this point. These findings demonstrated that Lcn2 served as a potent protective factor in response to systemic inflammation, and elevated Lcn2 expression during inflammatory conditions was presumed to play an effective role in alleviating inflammatory responses.


2015 ◽  
Vol 114 (08) ◽  
pp. 337-349 ◽  
Author(s):  
Dragana Komnenov ◽  
Corey Scipione ◽  
Zainab Bazzi ◽  
Justin Garabon ◽  
Marlys Koschinsky ◽  
...  

SummaryThrombin activatable fibrinolysis inhibitor (TAFI) is the zymogen form of a basic carboxypeptidase (TAFIa) with both anti-fibrinolytic and anti-inflammatory properties. The role of TAFI in inflammatory disease is multifaceted and involves modulation both of specific inflammatory mediators as well as of the behaviour of inflammatory cells. Moreover, as suggested by in vitro studies, inflammatory mediators are capable of regulating the expression of CPB2, the gene encoding TAFI. In this study we addressed the hypothesis that decreased TAFI levels observed in inflammation are due to post-transcriptional mechanisms. Treatment of human HepG2 cells with pro-inflammatory cytokines TNFα, IL-6 in combination with IL-1β, or with bacterial lipopolysaccharide (LPS) decreased TAFI protein levels by approximately two-fold over 24 to 48 hours of treatment. Conversely, treatment of HepG2 cells with the anti-inflammatory cytokine IL-10 increased TAFI protein levels by two-fold at both time points. We found that the mechanistic basis for this modulation of TAFI levels involves binding of tristetraprolin (TTP) to the CPB2 3′-UTR, which mediates CPB2 mRNA destabilisation. In this report we also identified that HuR, another ARE-binding protein but one that stabilises transcripts, is capable of binding the CBP2 3’UTR. We found that pro-inflammatory mediators reduce the occupancy of HuR on the CPB2 3’-UTR and that the mutation of the TTP binding site in this context abolishes this effect, although TTP and HuR appear to contact discrete binding sites. Interestingly, all of the mediators tested appear to increase TAFI protein expression in THP-1 macrophages, likewise through effects on CPB2 mRNA stability.


2019 ◽  
Vol 8 (12) ◽  
pp. 2211 ◽  
Author(s):  
Christian Behm ◽  
Alice Blufstein ◽  
Johannes Gahn ◽  
Barbara Kubin ◽  
Michael Nemec ◽  
...  

Periodontal ligament-derived mesenchymal stem cells (hPDLSCs) possess immunomodulatory abilities which are strongly enhanced by various inflammatory cytokines. Vitamin D3 has anti-inflammatory effects on hPDLSCs and immune cells. However, no study to date has directly compared the influence of 1,25(OH)2D3 on the immunomodulatory activities of hPDLSCs in the presence of different cytokines. In the present study, the effects of hPDLSCs treated with tumor necrosis factor (TNF)-α, interleukin (IL)-1β, or interferon (IFN)-γ in the presence of 1,25(OH)2D3 on the proliferation of allogenic CD4+ T lymphocyte or on the functional status of primary CD68+ macrophages were analyzed in coculture models. Additionally, the effects of 1,25(OH)2D3 on TNF-α-, IL-1β-, and IFN-γ-induced gene expression of some immunomodulatory factors in hPDLSCs were compared. Under coculture conditions, 1,25(OH)2D3 increased or decreased CD4+ T lymphocyte proliferation via hPDLSCs, depending on the cytokine. hPDLSCs primed with 1,25(OH)2D3 and different cytokines affected pro- and anti-inflammatory cytokine expression in macrophages variably, depending on the priming cytokine. With one exception, 1,25(OH)2D3 significantly reduced TNF-α-, IL-1β-, and IFN-γ-induced expression of all the investigated immunomediators in hPDLSCs, albeit to different extents. These results suggest that 1,25(OH)2D3 influences the immunomodulatory activities of hPDLSCs depending qualitatively and quantitatively on the presence of certain inflammatory cytokines.


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