scholarly journals The Mechanism of Leptin on Inhibiting Fibrosis and Promoting Browning of White Fat by Reducing ITGA5 in Mice

2021 ◽  
Vol 22 (22) ◽  
pp. 12353
Author(s):  
Yuexia Liu ◽  
Yizhou Li ◽  
Juntong Liang ◽  
Zhuwen Sun ◽  
Qiong Wu ◽  
...  

Leptin is a small molecule protein secreted by adipocytes, which can promote white fat browning through activating the hypothalamic nervous system and inhibiting downstream signaling pathways. Moreover, white fat browning has been proven to alleviate fat tissue fibrosis. This study explores the mechanism of leptin in regulating adipose tissue fibrosis and white fat browning. After treating mice with leptin, we screened out the recombinant integrin alpha 5 (ITGA5) through proteomics sequencing, which may play a role in adipose tissue fibrosis. Through real-time quantitative PCR (qPCR), western blotting (WB), hematoxylin-eosin (HE) staining, Masson’s trichrome, immunofluorescence, immunohistochemistry, etc., the results showed that after leptin treated adipocytes, the expression of fibrosis-related genes and ITGA5 was significantly down-regulated in adipocytes. We constructed fibrosis model through transforming growth factor-β (TGF-β) and a high-fat diet (HFD), and treated with ITGA5 overexpression vector and interference fragments. The results indicated the expression of fibrosis-related genes were significantly down-regulated after interfering with ITGA5. After treating adipocytes with wortmannin, fibrosis-related gene expression was inhibited after overexpression of ITGA5. Moreover, after injecting mice with leptin, we also found that leptin significantly up-regulated the expression of adipose tissue browning-related genes. Overall, our research shows that leptin can inhibit the activation of phosphatidylinositol 3 kinase (PI3K)-protein kinase B (AKT) signaling pathway by reducing the expression of ITGA5, which could alleviate adipose tissue fibrosis, and further promote white fat browning. Our research provides a theoretical basis for further research on the effect of leptin in fibrosis-related adipose tissue metabolism.

2018 ◽  
Vol 1 (3) ◽  
Author(s):  
Qishu Zhou ◽  
Chunyu Liang ◽  
Yafei Li ◽  
Yi Yan

Objective  To investigate the effect of one-time high-intensity intermittent exercise in white fat autophagy in obese rats and provide a theoretical basis of the molecular mechanism of exercise fat loss. Methods  Eighteen male 3-weeks-old rats were selected and divided into control group fed with normal diet (C), high-fat diet group fed with high fat diet (H). After 16 weeks, there were twelve obesity rats that divided into diet group (HS) and exercise group (HE). The other six control group rats of 19 weeks age were used as the standard (CS group). OE group did the high intensity intermittent exercise once. The CS group and the CS group were kept quietly. Three groups were taken subcutaneous white adipose tissue(S) and epididymal white adipose tissue (E) immediately after exercise. Mensurate the expression of LC3 gene in the tissue using the fluorescent quantitative PCR. Results 1. The expression of LC3 mRNA from white fat tissue was different to the tissues, which the expression of epididymal white adipose tissue of each group was higher than that in subcutaneous white adipose tissue (P <0.01). 2. Compared with CS group, the expression of epididymal white fat adipose tissue LC3 mRNA decreased (P<0.01) and the expression of the subcutaneous white adipose tissue increased from HS group (P <0.05). 3. Compared with OS group, the expression of epididymal white fat adipose tissue LC3 mRNA decreased (P<0.05) and the expression of subcutaneous white adipose tissue decreased from OS group. Conclusions The expression of LC3mRNA in epididymal white fat adipose tissue of rats was significantly higher than that of subcutaneous white fat. The changes of LC3mRNA expression of adipose tissue caused by high-fat diet have tissue differences. One-time high-intensity intermittent exercise can reduce the expression of LC3mRNA in fat tissue of obese rats. Its regulatory mechanism needs to be further studied.


Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Chris Happé ◽  
Nina Rol ◽  
Denielli Da Silva Goncalves Bos ◽  
Cathelijne van der Bruggen ◽  
Anton Vonk-Noordegraaf ◽  
...  

Introduction: Mutations in the bone morphogenetic protein recptor type 2 (BMPR2) comprise a large portion of familial Pulmonary Arterial Hypertension (PAH) cases. The transforming growth factor-β (TGF-β)/BMP-axis in PAH has been of interest, which is hypothesized to favor TGF-β signaling due to defective BMPR2 signaling, consequently leading to pro-proliferative signaling within the lung. In addition, it has been proposed that the BMPRII mutations might affect cardiac adaptation. To date none of the available animal models have been fully characterized with regard to the TGF-β/BMP pathway. This study assessed the lung and heart TGF-β/BMP-axis in multiple rat animal models of pulmonary hypertension to ensure translational capability. Methods: Heart and lung TGF-β/BMP-axis was assessed by qPCR, western blot and immunofluorescence in the the monocrotaline (MCT), Sugen-hypoxia (SuHx), Sugen-Pneumonectomy (SuPnx) and Pulmonary artery banding model (PAB) and compared to control and PAH patient tissues. Circulating ligands, TGF-β receptor (TGFβR) type 1 and 2 and BMPR2, and canonical downstream signaling (Smad2/3, Smad1/5/8, and transcription factors) were investigated. Results: BMPR2 was down-regulated at both transcription and protein levels in the lung of all PH animal models (p<0.05). Transcription of pulmonary TGFβR1 and -2 were increased in the SuPNx-model, compared to control (P<0.001). In both SuHx and SuPnx models an increase in protein Smad2/3 expression was observed by immunofluorescence implying overactivation of TGF-β signaling. Cardiac TGFβR1 was decreased in PAB model, compared to control (P<0.05), while TGFβR2 was decreased in both the MCT and PAB model. Conclusion: Early indications reveal differences between several pulmonary hypertension animal models, with regard to the TGF-β/BMP pathway. Additional analysis is needed to fully characterize the regulation of TGF-β and BMP in the rat models.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Meilin Hu ◽  
Fan Wu ◽  
Jinlong Luo ◽  
Jing Gong ◽  
Ke Fang ◽  
...  

Berberine (BBR) is the main active ingredient of a traditional Chinese herb Coptis chinensis. It has been reported to exhibit beneficial effects in treating diabetes and obesity. However, the underlying mechanism has not been fully elucidated. Adipose tissue fibrosis is a hallmark of obesity-associated adipose tissue dysfunction. HIF-1α plays a key role in adipose tissue fibrosis, which closely linked to metabolic dysfunction in obese state. We hypothesized that BBR may alleviate obesity-induced adipose tissue fibrosis and associated metabolic dysfunction through inhibition of HIF-1α. To test this hypothesis, we treated high fat diet (HFD) feeding mice with different dose of BBR (100 mg/kg, 200 mg/kg, and 300 mg/kg) for 8 weeks. We found that BBR treatment greatly decreased the body weight gain and reduced insulin resistance induced by HFD. Data also revealed that BBR improved histologic fibrous of epididymal white adipose tissue (eWAT) and was accompanied with inhibition of the abnormal synthesis and deposition of extracellular matrix (ECM) proteins, such as collagen and fibronectin. We also found that BBR treatment suppressed the expression of HIF-1α and decreased the mRNA expression of LOX in epididymal adipose tissue, which plays a key role in fibrosis development. Taken together, these results suggest that BBR can regulate metabolic homeostasis and suppress adipose tissue fibrosis through inhibiting the expression of HIF-1α.


2019 ◽  
Vol 20 (4) ◽  
pp. 873 ◽  
Author(s):  
Nesrine Ebrahim ◽  
Yasser Mandour ◽  
Ayman Farid ◽  
Ebtesam Nafie ◽  
Amira Mohamed ◽  
...  

This study was designed to investigate the potential effects and underlying mechanism of adipose tissue-derived mesenchymal stem cells (MSCs) on allergic inflammation compared to Montelukast as an antileukotriene drug in a rat model of allergic rhinitis (AR). The effect of MSCs was evaluated in albino rats that were randomly divided into four (control, AR, AR + Montelukast, and AR + MSCs) groups. Rats of AR group were sensitized by ovalbumin (OVA) and then challenged with daily nasal drops of OVA diluted in sterile physiological saline (50 μL/nostril, 100 mg/mL, 10% OVA) from day 15 to day 21 of treatment with/without Montelukast (1 h before each challenge) or MSCs I/P injection (1 × 106 MCSs; weekly for three constitutive weeks). Both Montelukast and MSCs treatment started from day 15 of the experiment. At the end of the 5th week, blood samples were collected from all rats for immunological assays, histological, and molecular biology examinations. Both oral Montelukast and intraperitoneal injection of MSCs significantly reduced allergic symptoms and OVA-specific immunoglobulin E (IgE), IgG1, IgG2a and histamine as well as increasing prostaglandin E2 (PGE2). Further analysis revealed that induction of nasal innate cytokines, such as interleukin (IL)-4 and TNF-α; and chemokines, such as CCL11 and vascular cell adhesion molecule-1 (VCAM-1), were suppressed; and transforming growth factor-β (TGF-β) was up-regulated in Montelukast and MSCs-treated groups with superior effect to MSCs, which explained their underlying mechanism. In addition, the adipose tissue-derived MSCs-treated group had more restoring effects on nasal mucosa structure demonstrated by electron microscopical examination.


Science ◽  
2019 ◽  
Vol 364 (6438) ◽  
pp. eaav2501 ◽  
Author(s):  
David Merrick ◽  
Alexander Sakers ◽  
Zhazira Irgebay ◽  
Chihiro Okada ◽  
Catherine Calvert ◽  
...  

Metabolic health depends on the capacity of adipose tissue progenitor cells to undergo de novo adipogenesis. The cellular hierarchy and mechanisms governing adipocyte progenitor differentiation are incompletely understood. Through single-cell RNA sequence analyses, we show that the lineage hierarchy of adipocyte progenitors consists of distinct mesenchymal cell types that are present in both mouse and human adipose tissues. Cells marked by dipeptidyl peptidase–4 (DPP4)/CD26 expression are highly proliferative, multipotent progenitors. During the development of subcutaneous adipose tissue in mice, these progenitor cells give rise to intercellular adhesion molecule–1 (ICAM1)/CD54–expressing (CD54+) committed preadipocytes and a related adipogenic cell population marked by Clec11a and F3/CD142 expression. Transforming growth factor–β maintains DPP4+ cell identity and inhibits adipogenic commitment of DPP4+ and CD142+ cells. Notably, DPP4+ progenitors reside in the reticular interstitium, a recently appreciated fluid-filled space within and between tissues, including adipose depots.


2013 ◽  
Vol 304 (9) ◽  
pp. C918-C926 ◽  
Author(s):  
Lluïsa Miró ◽  
Anna Pérez-Bosque ◽  
Mònica Maijó ◽  
Concepció Amat ◽  
Richard J. Naftalin ◽  
...  

In vivo studies show that raised aldosterone (Aldo) during low-Na adaptation regulates the growth of pericryptal myofibroblasts and reduces the permeability of the colonic epithelium. The aim of this study was to reproduce in vitro the in vivo condition of increased Aldo using human CCD-18Co myofibroblasts and T84 colonic epithelial cells to measure myofibroblast and epithelial proliferation and the expression of intercellular junction proteins. Proliferation was quantified by measuring 5-bromo-2′-deoxyuridine incorporation. The myofibroblast expression of EGF, VEGFa, and transforming growth factor-β1 (TGF-β1) was measured by real-time PCR and the expression of junctional complex proteins by Western blot. Aldo stimulated the proliferation of myofibroblasts by 70% ( P < 0.05) and increased EGF mRNA expression by 30% ( P < 0.05) without affecting VEGFa and TGF-β1. EGF concentration in the incubation medium increased by 30% ( P < 0.05) 24 h after Aldo addition, and these effects were prevented by the addition of spironolactone. Myofibroblast proliferation in response to Aldo was mediated by EGF receptor (EGFR) and involved both MAPKK and phosphatidylinositol 3-kinase pathways. When T84 cells were incubated with medium from myofibroblasts stimulated with Aldo (conditioned medium), the expression of β-catenin and claudin IV was increased by 30% ( P < 0.05) and proliferation by 40% ( P < 0.05). T84 proliferation decreased when α-EGF, or the EGFR antagonist AG1478, was present. Results in vivo indicate that rats fed a low-salt diet showed an increased expression of EGF and EGFR in the colonic mucosa. These results support the view that changes in colonic permeability during low-Na adaptation are mediated by the EGF secreted by myofibroblasts in response to raised Aldo.


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