scholarly journals Adipocyte mTORC1 deficiency promotes adipose tissue inflammation and NLRP3 inflammasome activation via oxidative stress and de novo ceramide synthesis

2017 ◽  
Vol 58 (9) ◽  
pp. 1797-1807 ◽  
Author(s):  
Patricia Chimin ◽  
Maynara L. Andrade ◽  
Thiago Belchior ◽  
Vivian A. Paschoal ◽  
Juliana Magdalon ◽  
...  
2014 ◽  
Vol 96 (6) ◽  
pp. 1087-1100 ◽  
Author(s):  
Hiroe Honda ◽  
Yoshinori Nagai ◽  
Takayuki Matsunaga ◽  
Naoki Okamoto ◽  
Yasuharu Watanabe ◽  
...  

2017 ◽  
Vol 235 (3) ◽  
pp. 179-191 ◽  
Author(s):  
Tsutomu Wada ◽  
Akari Ishikawa ◽  
Eri Watanabe ◽  
Yuto Nakamura ◽  
Yusuke Aruga ◽  
...  

Obesity-associated activation of the renin-angiotensin-aldosterone system is implicated in the pathogenesis of insulin resistance; however, influences of mineralocorticoid receptor (MR) inhibition remain unclear. Therefore, we aimed to clarify the anti-inflammatory mechanisms of MR inhibition using eplerenone, a selective MR antagonist, in C57BL/6 mice fed a high-fat diet (HFD) for 12 weeks. Eplerenone prevented excessive body weight gain and fat accumulation, ameliorated glucose intolerance and insulin resistance and enhanced energy metabolism. In the epididymal white adipose tissue (eWAT), eplerenone prevented obesity-induced accumulation of F4/80+CD11c+CD206−-M1-adipose tissue macrophage (ATM) and reduction of F4/80+CD11c−CD206+-M2-ATM. Interestingly, M1-macrophage exhibited lower expression levels of MR, compared with M2-macrophage, in the ATM of eWAT and in vitro-polarized bone marrow-derived macrophages (BMDM). Importantly, eplerenone and MR knockdown attenuated the increase in the expression levels of proIl1b, Il6 and Tnfa, in the eWAT and liver of HFD-fed mice and LPS-stimulated BMDM. Moreover, eplerenone suppressed IL1b secretion from eWAT of HFD-fed mice. To reveal the anti-inflammatory mechanism, we investigated the involvement of NLRP3-inflammasome activation, a key process of IL1b overproduction. Eplerenone suppressed the expression of the inflammasome components, Nlrp3 and Caspase1, in the eWAT and liver. Concerning the second triggering factors, ROS production and ATP- and nigericin-induced IL1b secretion were suppressed by eplerenone in the LPS-primed BMDM. These results indicate that eplerenone inhibited both the priming and triggering signals that promote NLRP3-inflammasome activation. Therefore, we consider MR to be a crucial target to prevent metabolic disorders by suppressing inflammasome-mediated chronic inflammation in the adipose tissue and liver under obese conditions.


Toxins ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 502
Author(s):  
Shoma Tanaka ◽  
Hiroshi Watanabe ◽  
Takehiro Nakano ◽  
Tadashi Imafuku ◽  
Hiromasa Kato ◽  
...  

Adipose tissue inflammation appears to be a risk factor for the progression of chronic kidney disease (CKD), but the effect of CKD on adipose tissue inflammation is poorly understood. The purpose of this study was to clarify the involvement of uremic toxins (indoxyl sulfate (IS), 3-indoleacetic acid, p-cresyl sulfate and kynurenic acid) on CKD-induced adipose tissue inflammation. IS induces monocyte chemoattractant protein-1 (MCP-1) expression and reactive oxygen species (ROS) production in the differentiated 3T3L-1 adipocyte. An organic anion transporter (OAT) inhibitor, an NADPH oxidase inhibitor or an antioxidant suppresses the IS-induced MCP-1 expression and ROS production, suggesting the OAT/NADPH oxidase/ROS pathway is involved in the action of IS. Co-culturing 3T3L-1 adipocytes and mouse macrophage cells showed incubating adipocytes with IS increased macrophage infiltration. An IS-overload in healthy mice increased IS levels, oxidative stress and MCP-1 expression in epididymal adipose tissue compared to unloaded mice. Using 5/6-nephrectomized mice, the administration of AST-120 suppressed oxidative stress and the expression of MCP-1, F4/80 and TNF-α in epididymal adipose tissue. These collective data suggest IS could be a therapeutic target for the CKD-related inflammatory response in adipose tissue, and that AST-120 could be useful for the treatment of IS-induced adipose tissue inflammation.


2020 ◽  
Vol 21 (11) ◽  
pp. 4184 ◽  
Author(s):  
Kelvin Ka-Lok Wu ◽  
Samson Wing-Ming Cheung ◽  
Kenneth King-Yip Cheng

Adipose tissue is an active endocrine and immune organ that controls systemic immunometabolism via multiple pathways. Diverse immune cell populations reside in adipose tissue, and their composition and immune responses vary with nutritional and environmental conditions. Adipose tissue dysfunction, characterized by sterile low-grade chronic inflammation and excessive immune cell infiltration, is a hallmark of obesity, as well as an important link to cardiometabolic diseases. Amongst the pro-inflammatory factors secreted by the dysfunctional adipose tissue, interleukin (IL)-1β, induced by the NLR family pyrin domain-containing 3 (NLRP3) inflammasome, not only impairs peripheral insulin sensitivity, but it also interferes with the endocrine and immune functions of adipose tissue in a paracrine manner. Human studies indicated that NLRP3 activity in adipose tissues positively correlates with obesity and its metabolic complications, and treatment with the IL-1β antibody improves glycaemia control in type 2 diabetic patients. In mouse models, genetic or pharmacological inhibition of NLRP3 activation pathways or IL-1β prevents adipose tissue dysfunction, including inflammation, fibrosis, defective lipid handling and adipogenesis, which in turn alleviates obesity and its related metabolic disorders. In this review, we summarize both the negative and positive regulators of NLRP3 inflammasome activation, and its pathophysiological consequences on immunometabolism. We also discuss the potential therapeutic approaches to targeting adipose tissue inflammasome for the treatment of obesity and its related metabolic disorders.


Nutrients ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 342 ◽  
Author(s):  
Alexandra Marziou ◽  
Clothilde Philouze ◽  
Charlène Couturier ◽  
Julien Astier ◽  
Philippe Obert ◽  
...  

The beneficial effect of vitamin D (VD) supplementation on body weight gain limitation and inflammation has been highlighted in primary prevention mice models, but the long-term effect of VD supplementation in tertiary prevention has never been reported in obesity models. The curative effect of VD supplementation on obesity and associated disorders was evaluated in high-fat- and high-sucrose (HFS)-fed mice. Morphological, histological, and molecular phenotype were characterized. The increased body mass and adiposity caused by HFS diet as well as fat cell hypertrophy and glucose homeostasis were not improved by VD supplementation. However, VD supplementation led to a decrease of HFS-induced inflammation in inguinal adipose tissue, characterized by a decreased expression of chemokine mRNA levels. Moreover, a protective effect of VD on HFS-induced hepatic steatosis was highlighted by a decrease of lipid droplets and a reduction of triglyceride accumulation in the liver. This result was associated with a significant decrease of gene expression coding for key enzymes involved in hepatic de novo lipogenesis and fatty acid oxidation. Altogether, our results show that VD supplementation could be of interest to blunt the adipose tissue inflammation and hepatic steatosis and could represent an interesting nutritional strategy to fight obesity-associated comorbidities.


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