Hypoxic Tumor-Derived Exosomal Circ0048117 Facilitates M2 Macrophage Polarization Acting as miR-140 Sponge in Esophageal Squamous Cell Carcinoma
ONCOTARGETS AND THERAPY
Authors: Lu, Qijue; Wang, Xinyu; Zhu, Ji; Fei, Xiang; Chen, Hezhong; Li, Chunguang
Abstract
Introduction: Hypoxia and tumor-associated macrophage (TAM) are key regulators in remodeling the microenvironment of esophageal squamous cell carcinoma (ESCC). Hypoxia could stimulate tumor cells to secrete more exosomes and activate TAMs to M2 type. Here, we investigated the function and the underlying mechanism of tumor-derived exosomal hsa-circ-0048117 in TAM polarization in ESCC. Collectively, these data indicate that PC cells generate miR-301a-3p-rich exosomes in a hypoxic microenvironment, which then polarize macrophages to promote malignant behaviors of PC cells. Methods: Transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA) were used to analyze the physical characteristics of exosomes. High-throughput sequencing and bioinformatic analysis were performed to screen the potential exosomal circRNA. FISH, Ago2 RIP, pull-down and dual-luciferase reporter assay were conducted to figure out the correlation among hsa-circ-0048117, miR-140 and toll-like receptor 4 (TLR4). Flow cytometry and Western blot were used to evaluate their joint effect in macrophages polarization. Then, the invasion and migration ability were evaluated by transwell experiment. At last, serum exo-hsa-circ-0048117 in ESCC patients was compared and the correlation between its expression and T stage, N stage and TNM grades was analyzed. Results: Hsa-circ-0048117 was significantly upregulated and enriched in exosomes secreted by hypoxia pre-challenged tumor cells and contributed to M2 macrophage polarization. Hsa-circ-0048117 depletion in macrophage led to inhibition of M2 polarization while restoration of hsa-circ-0048117 could rescue the process. Moreover, hsa-circ-0048117 could act as sponge of miR-140 by competing with TLR4 to facilitate the M2 macrophage polarization. Exo-hsa-circ-0048117 could be transmitted to macrophages to promote M2 polarization and M2 macrophages could enhance the ability of invasion and migration of tumor cells by secreting Arg1, IL-10 and TGF-beta. Higher serum exo-hsa-circ-0048117 predicted an advanced T and N stage and positively correlated with TNM grade. Conclusion: Our findings indicated that ESCC cells generate hsa-circ-0048117-rich exosomes in a hypoxic microenvironment; hsa-circ-0048117 was believed to promote M2 macrophage polarization which favors the malignant behaviors of ESCC cells. These results reminded us that exosomal hsa-circ-0048117 may play a key role in remodeling the micro environment and modulating progression in ESCC.
Gliptins Suppress Inflammatory Macrophage Activation to Mitigate Inflammation, Fibrosis, Oxidative Stress, and Vascular Dysfunction in Models of Nonalcoholic Steatohepatitis and Liver Fibrosis
ANTIOXIDANTS & REDOX SIGNALING
Authors: Wang, Xiaoyu; Hausding, Michael; Weng, Shih-Yen; Kim, Yong Ook; Steven, Sebastian; Klein, Thomas; Daiber, Andreas; Schuppan, Detlef
Abstract
Aims: Nonalcoholic steatohepatitis (NASH) is characterized by steatosis, panlobular inflammation, liver fibrosis, and increased cardiovascular mortality. Dipeptidyl peptidase-4 inhibitors (gliptins) are indirect glucagon-like peptide 1 agonists with antidiabetic and anti-inflammatory activity, used for the treatment of type 2 diabetes. Their potential and underlying mechanisms to treat metabolic liver inflammation and fibrosis as well as the associated vascular dysfunction remain to be explored. Results: In the methionine/choline-deficient (MCD) diet and Mdr2(-/-) models of NASH and liver fibrosis, treatment with sitagliptin and linagliptin significantly decreased parameters of steatosis and inflammation, which was accompanied by suppression of hepatic transcript levels reflecting metabolic inflammation and fibrosis, including SREBP-1c, FAS, TNF, iNOS, -SMA, Col11, and MMP-12. Moreover, gliptins reduced the number of liver infiltrating CD11b(+)Ly6C(hi) proinflammatory monocytes/macrophages and liver-resident F4/80(+) macrophages, with an increase of Ym1(+) alternative macrophages and (anti-inflammatory) macrophage markers Arg1 and IL-10. This was paralleled by decreased hepatic and aortic reactive oxygen species (ROS) production and NOX-2 mRNA expression, a normalization of endothelial dysfunction, cardiac NADPH oxidase activity, mitochondrial ROS formation, and whole blood oxidative burst in the MCD model. Innovation and Conclusions: Gliptins via suppression of inflammation decrease steatosis, apoptosis, oxidative stress, and vascular dysfunction in murine models of NASH and liver fibrosis, with mild direct antifibrotic properties. They reduce the numbers of liver and vascular inflammatory monocytes/macrophages and induce their alternative polarization, with beneficial effect on NASH-associated hepatic and cardiovascular complications. Therefore, gliptins qualify as drugs for treatment of NASH and associated liver fibrosis and cardiovascular complications. Antioxid. Redox Signal. 28, 87-109.