scholarly journals The obesity-induced adipokine sST2 exacerbates adipose Treg and ILC2 depletion and promotes insulin resistance

2020 ◽  
Vol 6 (20) ◽  
pp. eaay6191 ◽  
Author(s):  
Xu-Yun Zhao ◽  
Linkang Zhou ◽  
Zhimin Chen ◽  
Yewei Ji ◽  
Xiaoling Peng ◽  
...  

Depletion of fat-resident regulatory T cells (Tregs) and group 2 innate lymphoid cells (ILC2s) has been causally linked to obesity-associated insulin resistance. However, the molecular nature of the pathogenic signals suppress adipose Tregs and ILC2s in obesity remains unknown. Here, we identified the soluble isoform of interleukin (IL)–33 receptor ST2 (sST2) as an obesity-induced adipokine that attenuates IL-33 signaling and disrupts Treg/ILC2 homeostasis in adipose tissue, thereby exacerbates obesity-associated insulin resistance in mice. We demonstrated sST2 is a target of TNFα signaling in adipocytes that is countered by Zbtb7b. Fat-specific ablation of Zbtb7b augments adipose sST2 gene expression, leading to diminished fat-resident Tregs/ILC2s, more pronounced adipose tissue inflammation and fibrosis, and impaired glucose homeostasis in mice. Mechanistically, Zbtb7b suppresses NF-κB activation in response to TNFα through destabilizing IκBα. These findings uncover an adipokine-immune signaling pathway that is engaged in obesity to drive the pathological changes of the immunometabolic landscape.

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Pedram Shafiei-Jahani ◽  
Benjamin P. Hurrell ◽  
Lauriane Galle-Treger ◽  
Doumet Georges Helou ◽  
Emily Howard ◽  
...  

Abstract Disturbances in glucose homeostasis and low-grade chronic inflammation culminate into metabolic syndrome that increase the risk for the development of type 2 diabetes mellitus (T2DM). The recently discovered group 2 innate lymphoid cells (ILC2s) are capable of secreting copious amounts of type 2 cytokines to modulate metabolic homeostasis in adipose tissue. In this study, we have established that expression of Death Receptor 3 (DR3), a member of the TNF superfamily, on visceral adipose tissue (VAT)-derived murine and peripheral blood human ILC2s is inducible by IL-33. We demonstrate that DR3 engages the canonical and/or non-canonical NF-κB pathways, and thus stimulates naïve and co-stimulates IL-33-activated ILC2s. Importantly, DR3 engagement on ILC2s significantly ameliorates glucose tolerance, protects against insulin-resistance onset and remarkably reverses already established insulin-resistance. Taken together, these results convey the potent role of DR3 as an ILC2 regulator and introduce DR3 agonistic treatment as a novel therapeutic avenue for treating T2DM.


2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Vlad Serbulea ◽  
Akshaya K Meher ◽  
Samantha Adamson ◽  
Norbert Leitinger

Our group has previously shown that oxidized phospholipids (OxPL) induce a unique macrophage (MΦ) phenotype known as “Mox,” distinct from pro- and anti-inflammatory M1 and M2 phenotypes. We have also shown that Mox make up 30% of the MΦs found in atherosclerotic lesions. OxPL induce TLR2-dependent inflammatory gene expression in MΦs. TLR2 activation by peptidoglycan was shown to induce accumulation of ceramides, which can alter bioenergetics by inhibiting the mitochondria. Recently, it has been shown that spleen tyrosine kinase (Syk) is phosphorylated upon TLR2 agonist Pam3CSK stimulation in MΦs. The effect of OxPL on bioenergetics has never before been studied. Here we test the hypothesis that OxPL change MΦ bioenergetics and inflammatory capacity via a TLR2-Syk-Ceramide pathway. Using flow cytometry, we found that in mice fed a high-fat diet, more than 20% of all adipose tissue MΦs can be described as Mox. Concomitantly, using immunohistochemistry and liquid-chromatography mass spectrometry, we measured increased levels of OxPL in the stromal vascular fraction of obese murine adipose tissue, as compared to lean controls. We treated bone marrow-derived MΦs (BMDMs) from WT, TLR2-KO, and Syk-KO mice with OxPL and measured bioenergetics using a Seahorse Flux Analyzer. Our results show that OxPL decrease oxygen consumption rate (OCR), a measure of oxidative phosphorylation, and decrease extracellular acidification rate (ECAR), a measure of glycolytic capacity. These MΦs can be described as quiescent, but they still engage in low-level cytokine production. Moreover, OxPL result in the accumulation of ceramides, as quantified by mass spectrometry. Finally, using Syk-KO MΦs and Syk inhibitors, we show that OxPL-induced inflammatory gene expression and ceramide accumulation are dependent on Syk. In summary, our results demonstrate that OxPL accumulate in obese adipose tissue and induce a change in the inflammatory and metabolic profiles of MΦs, involving a TLR2-ceramide-Syk dependent pathway. These results suggest that OxPL are triggers of adipose tissue inflammation and subsequent development of insulin resistance. Furthermore, we identify Syk as a therapeutic target for inhibiting diet-induced adipose tissue inflammation and insulin resistance.


Cytokine ◽  
2015 ◽  
Vol 75 (2) ◽  
pp. 280-290 ◽  
Author(s):  
Dov B. Ballak ◽  
Rinke Stienstra ◽  
Cees J. Tack ◽  
Charles A. Dinarello ◽  
Janna A. van Diepen

Author(s):  
Charmaine S. Tam ◽  
Leanne M. Redman

AbstractObesity is characterized by a state of chronic low-grade inflammation due to increased immune cells, specifically infiltrated macrophages into adipose tissue, which in turn secrete a range of proinflammatory mediators. This nonselective low-grade inflammation of adipose tissue is systemic in nature and can impair insulin signaling pathways, thus, increasing the risk of developing insulin resistance and type 2 diabetes. The aim of this review is to provide an update on clinical studies examining the role of adipose tissue in the development of obesity-associated complications in humans. We will discuss adipose tissue inflammation during different scenarios of energy imbalance and metabolic dysfunction including obesity and overfeeding, weight loss by calorie restriction or bariatric surgery, and conditions of insulin resistance (diabetes, polycystic ovarian syndrome).


Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Rieko Takanabe ◽  
Koh Ono ◽  
Tomohide Takaya ◽  
Takahiro Horie ◽  
Hiromichi Wada ◽  
...  

Obesity is the result of an expansion and increase in the number of individual adipocytes. Since changes in gene expression during adipocyte differentiation and hypertrophy are closely associated with insulin resistance and cardiovascular diseases, further insight into the molecular basis of obesity is needed to better understand obesity-associated diseases. MicroRNAs (miRNAs) are approximately 17–24nt single stranded RNA, that post-transcriptionally regulate gene expression. MiRNAs control cell growth, differentiation and metabolism, and may be also involved in pathogenesis and pathophysiology of diseases. It has been proposed that miR-143 plays a role in the differentiation of preadipocytes into mature adipocytes in culture. However, regulated expression of miR-143 in the adult adipose tissue during the development of obesity in vivo is unknown. To solve this problem, C57BL/6 mice were fed with either high-fat diet (HFD) or normal chow (NC). Eight weeks later, severe insulin resistance was observed in mice on HFD. Body weight increased by 35% and the mesenteric fat weight increased by 3.3-fold in HFD mice compared with NC mice. We measured expression levels of miR-143 in the mesenteric fat tissue by real-time PCR and normalized with those of 5S ribosomal RNA. Expression of miR-143 in the mesenteric fat was significantly up-regulated (3.3-fold, p<0.05) in HFD mice compared to NC mice. MiR-143 expression levels were positively correlated with body weight (R=0.577, p=0.0011) and the mesenteric fat weight (R=0.608, p=0.0005). We also measured expression levels in the mesenteric fat of PPARγ and AP2, whose expression are deeply involved in the development of obesity, insulin resistant and arteriosclerosis. The expression levels of miR-143 were closely correlated with those of PPARγ (R=0.600, p=0.0040) and AP2 (R=0.630, p=0.0022). These findings provide the first evidence for up-regulated expression of miR-143 in the mesenteric fat of HFD-induced obese mice, which might contribute to regulated expression of genes involved in the pathophysiology of obesity.


Diabetes ◽  
2016 ◽  
Vol 65 (9) ◽  
pp. 2624-2638 ◽  
Author(s):  
Mira Ham ◽  
Sung Sik Choe ◽  
Kyung Cheul Shin ◽  
Goun Choi ◽  
Ji-Won Kim ◽  
...  

2007 ◽  
Vol 97 (2) ◽  
pp. 389-398 ◽  
Author(s):  
Patricia Pérez-Matute ◽  
Nerea Pérez-Echarri ◽  
J. Alfredo Martínez ◽  
Amelia Marti ◽  
María J. Moreno-Aliaga

n-3 PUFA have shown potential anti-obesity and insulin-sensitising properties. However, the mechanisms involved are not clearly established. The aim of the present study was to assess the effects of EPA administration, one of the n-3 PUFA, on body-weight gain and adiposity in rats fed on a standard or a high-fat (cafeteria) diet. The actions on white adipose tissue lipolysis, apoptosis and on several genes related to obesity and insulin resistance were also studied. Control and cafeteria-induced overweight male Wistar rats were assigned into two subgroups, one of them daily received EPA ethyl ester (1 g/kg) for 5 weeks by oral administration. The high-fat diet induced a very significant increase in both body weight and fat mass. Rats fed with the cafeteria diet and orally treated with EPA showed a marginally lower body-weight gain (P = 0·09), a decrease in food intake (P < 0·01) and an increase in leptin production (P < 0·05). EPA administration reduced retroperitoneal adipose tissue weight (P < 0·05) which could be secondary to the inhibition of the adipogenic transcription factor PPARγ gene expression (P < 0·001), and also to the increase in apoptosis (P < 0·05) found in rats fed with a control diet. TNFα gene expression was significantly increased (P < 0·05) by the cafeteria diet, while EPA treatment was able to prevent (P < 0·01) the rise in this inflammatory cytokine. Adiposity-corrected adiponectin plasma levels were increased by EPA. These actions on both TNFα and adiponectin could explain the beneficial effects of EPA on insulin resistance induced by the cafeteria diet.


Sign in / Sign up

Export Citation Format

Share Document