scholarly journals Urolithin A, a Gut Metabolite, Induces Metabolic Reprogramming of Adipose Tissue by Promoting M2 Macrophage Polarization and Mitochondrial Function (OR12-02-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Ashley Toney ◽  
Soonkyu Chung

Abstract Objectives Macrophage polarization into pro-inflammatory M1 status is associated with the pathologic progression of adipose remodeling, while M2 polarization is linked with the resolution of inflammation. Urolithin A (UroA) is a gut metabolite derived from ellagic acid found in berries and nuts. Emerging evidence suggests UroA exerts anti-inflammatory function, but the underlying mechanism remains unknown. This study aims to test the hypothesis that UroA attenuates adipose inflammation by promoting M2 macrophage polarization. Methods To investigate the direct role of UroA in vitro, primary bone marrow-derived macrophages (BMDM) were stimulated with LPS for M1 polarization or IL-4/IL-13 for M2 polarization. Oxygen consumption rate was determined in BMDM by Seahorse extracellular flux analyzer. The anti-inflammatory role of UroA is validated by pro-IL-1β Gaussia luciferase (iGLuc) reporter assay and IL-1β secretion in J774 macrophages. Additionally, C57BL/6 mice were fed with a HF diet for 12 weeks along with UroA administration. The M1/M2 polarization status were examined in adipose tissue macrophages (ATM) and peritoneal macrophages by qPCR and protein markers. Results UroA treatment in BMDM in vitro significantly decreased Il-1β (P < 0.001), while increasing M2 markers of Arg1, Ch313 and Mgl2 (P < 0.01). UroA treatment suppressed NLRP3 inflammasome activation in J774 macrophages by decreasing iGLuc activity and IL-1β secretion in a dose-dependent manner. In vivo, UroA administration reduced HF-induced adipocyte hypertrophy, inflammatory markers, and ATM recruitment (P < 0.01) in the adipose tissue. Consistently, UroA suppressed M1 polarization but switched to M2 polarization in peritoneal macrophages, evidenced by decreased M1 signature genes of Cd11c, Tnf-α, Il-6, and Il-1β (P < 0.01), while elevated M2 markers of Ch313 and Mgl2 (P < 0.05). Lastly, UroA not only inhibits HF-driven pathogenic remodeling of adipose tissue, but also promote mitochondrial function and biogenesis. Conclusions UroA attenuates HF-driven pathologic remodeling of adipose tissue by favoring M2 macrophage polarization and augmenting mitochondrial function. Intake of UroA-producing foods may be a promising intervention strategy to mitigate obesity-mediated chronic inflammation and metabolic dysfunction. Funding Sources United States Department of Agriculture National Institute for Food and Agriculture.

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Wei Liu ◽  
Muyu Yu ◽  
Feng Chen ◽  
Longqing Wang ◽  
Cheng Ye ◽  
...  

Abstract Background Many patients suffer from implant loosening after the implantation of titanium alloy caused by immune response to the foreign bodies and this could inhibit the following osteogenesis, which could possibly give rise to aseptic loosening and poor osteointegration while there is currently no appropriate solution in clinical practice. Exosome (Exo) carrying miRNA has been proven to be a suitable nanocarrier for solving this problem. In this study, we explored whether exosomes overexpressing miR-181b (Exo-181b) could exert beneficial effect on promoting M2 macrophage polarization, thus inhibiting inflammation as well as promoting osteogenesis and elaborated the underlying mechanism in vitro. Furthermore, we aimed to find whether Exo-181b could enhance osteointegration. Results In vitro, we firstly verified that Exo-181b significantly enhanced M2 polarization and inhibited inflammation by suppressing PRKCD and activating p-AKT. Then, in vivo, we verified that Exo-181b enhanced M2 polarization, reduced the inflammatory response and enhanced osteointegration. Also, we verified that the enhanced M2 polarization could indirectly promote the migration and osteogenic differentiation by secreting VEGF and BMP-2 in vitro. Conclusions Exo-181b could suppress inflammatory response by promoting M2 polarization via activating PRKCD/AKT signaling pathway, which further promoting osteogenesis in vitro and promote osteointegration in vivo. Graphic abstract


2019 ◽  
Vol 242 (2) ◽  
pp. 91-101 ◽  
Author(s):  
Monisha Rajasekaran ◽  
Ok-Joo Sul ◽  
Eun-Kyung Choi ◽  
Ji-Eun Kim ◽  
Jae-Hee Suh ◽  
...  

Obesity is strongly associated with chronic inflammation for which adipose tissue macrophages play a critical role. The objective of this study is to identify monocyte chemoattractant protein-1 (MCP-1, CCL2) as a key player governing M1–M2 macrophage polarization and energy balance. We evaluated body weight, fat mass, adipocyte size and energy expenditure as well as core body temperature of Ccl2 knockout mice compared with wild-type mice. Adipose tissues, differentiated adipocyte and bone marrow-derived macrophages were assessed by qPCR, Western blot analysis and histochemistry. MCP-1 deficiency augmented energy expenditure by promoting browning in white adipose tissue and brown adipose tissue activity via increasing the expressions of Ucp1, Prdm16, Tnfrsf9, Ppargc1a, Nrf1 and Th and mitochondrial DNA copy number. MCP-1 abrogation promoted M2 polarization which is characterized by increased expression of Arg1, Chil3, Il10 and Klf4 whereas it decreased M1 polarization by decreased p65 nuclear translocation and attenuated expression of Itgax, Tnf and Nos2, leading to increased browning of adipocytes. Enhanced M2 polarization and attenuated M1 polarization in the absence of MCP-1 are independent. Collectively, our results suggest that the action of MCP-1 in macrophages modulates energy expenditure by impairing browning in adipose tissue.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Pingping Wang ◽  
Zhenzhi Ma ◽  
Zengyan Wang ◽  
Ximei Wang ◽  
Guifeng Zhao ◽  
...  

The role of microRNA (miRNA) in gestational diabetes mellitus has been widely investigated during the last decade. However, the altering effect of miR-6869-5p on immunity and placental microenvironment in gestational diabetes mellitus is largely unknown. In our study, the expression of miR-6869-5p was documented to be significantly decreased in placenta-derived mononuclear macrophages, which was also negatively related to PTPRO. Besides, PTPRO was negatively regulated by miR-6869-5p in placenta-derived mononuclear macrophages. In vitro, miR-6869-5p inhibited macrophage proliferation demonstrated by EdU and CCK-8 experiments. The inflammatory response in macrophages was also significantly inhibited by miR-6869-5p, which could regulate PTPRO as a target documented by luciferase reporter assay. Moreover, miR-6869-5p promoted M2 macrophage polarization and thus restrain inflammation. Accordingly, miR-6869-5p is involved in maintaining placental microenvironment balance by preventing from inflammation and inducing M2 macrophages in gestational diabetes mellitus.


2019 ◽  
Vol 317 (4) ◽  
pp. C762-C775 ◽  
Author(s):  
Yihan Liu ◽  
Zhujiang Liu ◽  
Hao Tang ◽  
Yicong Shen ◽  
Ze Gong ◽  
...  

Compelling evidence indicates that epigenetic regulations orchestrate dynamic macrophage polarization. N6-methyladenosine (m6A) methylation is the most abundant epigenetic modification of mammalian mRNA, but its role in macrophage polarization is still completely unknown. Here, we show that the m6A-catalytic enzyme methyltransferase like 3 (METTL3) is specifically upregulated following the M1 polarization of mouse macrophages. Furthermore, METTL3 knockdown through siRNA transfection markedly inhibited M1, but enhanced M2, macrophage polarization. Conversely, its overexpression via plasmid transfection greatly facilitated M1, but attenuated M2, macrophage polarization. Further methylated RNA immunoprecipitation and in vitro m6A methylation assays suggested that METTL3 directly methylates mRNA encoding signal transducer and activator of transcription 1 (STAT1), a master transcription factor controlling M1 macrophage polarization, at its coding sequence and 3′-untranslated regions. In addition, METTL3-mediated STAT1 mRNA methylation significantly increased mRNA stability and subsequently upregulated STAT1 expression. In conclusion, METTL3 drives M1 macrophage polarization by directly methylating STAT1 mRNA, potentially serving as an anti-inflammatory target.


Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 855
Author(s):  
Ekaterina A. Litvinova ◽  
Victoria D. Bets ◽  
Natalya A. Feofanova ◽  
Olga V. Gvozdeva ◽  
Kseniya M. Achasova ◽  
...  

Intestinal mucus protects epithelial and immune cells from the gut resident microorganisms, and provides growth-promoting factors as mucus-derived O-glycans for beneficial bacteria. A lack of intestinal protective mucus results in changes in the commensal microflora composition, mucosal immune system reprogramming, and inflammation. Previous work has shown that fucose, the terminal glycan chain component of the intestinal glycoprotein Mucin2, and fucoidan polysaccharides have an anti-inflammatory effect in some mouse models of colitis. This study evaluates the effect of fucose on reproductive performance in heterozygous mutant Muc2 female mice. We found that even though Muc2+/− females are physiologically indistinguishable from C57Bl/6 mice, they have a significantly reduced reproductive performance upon dietary fucose supplementation. Metagenomic analysis reveals that the otherwise healthy wild-type siblings of Muc2−/− animals have reduced numbers of some of the intestinal commensal bacterial species, compared to C57BL/6 mice. We propose that the changes in beneficial microflora affect the immune status in Muc2+/− mice, which causes implantation impairment. In accordance with this hypothesis, we find that macrophage polarization during pregnancy is impaired in Muc2+/− females upon addition of fucose. Metabolic profiling of peritoneal macrophages from Muc2+/− females reveals their predisposition towards anaerobic glycolysis in favor of oxidative phosphorylation, compared to C57BL/6-derived cells. In vitro experiments on phagocytosis activity and mitochondrial respiration suggest that fucose affects oxidative phosphorylation in a genotype-specific manner, which might interfere with implantation depending on the initial status of macrophages. This hypothesis is further confirmed in BALB/c female mice, where fucose caused pregnancy loss and opposed implantation-associated M2 macrophage polarization. Taken together, these data suggest that intestinal microflora affects host immunity and pregnancy outcome. At the same time, dietary fucose might act as a differential regulator of macrophage polarization during implantation, depending on the immune status of the host.


Nanoscale ◽  
2019 ◽  
Vol 11 (39) ◽  
pp. 18209-18223 ◽  
Author(s):  
Xu Chen ◽  
Xufeng Zhu ◽  
Litao Ma ◽  
Ange Lin ◽  
Youcong Gong ◽  
...  

A novel therapeutic strategy for inducing macrophage M2 polarization by a core–shell QRu-PLGA-RES-DS NPs nanocomposite with photothermal response for RA therapy.


2016 ◽  
Vol 36 (4) ◽  
Author(s):  
Yan Zhong ◽  
Chun Yi

Macrophages are highly plastic cells with the ability to differentiate into both M1- and M2-polarized phenotypes. As a distinct M2-polarized population, tumour-associated macrophages (TAMs) promote tumorigenesis owing to their pro-angiogenic and immune-suppressive functions in tumour microenvironment. In the present study, we found that the microRNA-720 (miR-720) was down-regulated in TAMs isolated from breast carcinomas and M2-polarization macrophages. Overexpression of miR-720 attenuated M2 phenotype expression and thus inhibited M2 polarization. We further identified GATA binding protein 3 (GATA3), a transcriptional factor that plays an important role in M2 macrophage polarization, was the downstream target of miR-720. Ectopic expression of GATA3 restored the M2 phenotype in miR-720 overexpressed macrophages. Importantly, overexpression of miR-720 inhibited pro-migration behaviour and phagocytic ability of M2-polarized macrophages. Thus, our data suggest that miR-720 plays an important role in regulating M2 macrophage polarization and function.


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