scholarly journals Role of SMAD2 and SMAD3 on Adipose Tissue Development and Function

2021 ◽  
Author(s):  
◽  
Roshan Kumari ◽  
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
Fat Mass ◽  
Energy Homeostasis ◽  
Activin A ◽  
Male Mice ◽  
Proliferation And Differentiation

Introduction: Obesity and its associated metabolic syndrome are major medical problems worldwide including United States. Adipose tissue is the primary site of energy storage, playing important roles in health. Adipose tissue also has other critical functions, producing adipocytokines and contributing to normal nutrient metabolism, which in turn play important roles in satiety, inflammation, and total energy homeostasis. Activin A and activin B play important roles in maintaining body composition and energy homeostasis. This dissertation highlights the role of activin/SMADs signaling in adipose tissue development, function, and maintenance. SMAD2/3 proteins are downstream mediators of transforming growth factor-β (TGFβ) family signaling, including activins, which regulate critical preadipocyte and mature adipocyte functions. Previous studies have demonstrated that Smad2 global knockout mice exhibit embryonic lethality, whereas global loss of Smad3 protects mice against diet-induced obesity and the direct contributions of Smad2 and Smad3 in adipose tissues individually or in combination and the responses of these tissues to activin signaling are unknown. Additionally, our lab demonstrated that the combined loss of activin A and activin B have reduced adiposity in mice and appearance of brown-like cells in visceral white adipose tissue. However, the cell-autonomous role of activins on cell proliferation and differentiation remained unknown in vitro. My hypothesis was that activin signaling regulate adipocyte differentiation and functions via SMAD2/3-mediated mechanism(s) and that the individual or combined adipose-specific deletion of SMAD2/SMAD3 would result in reduced adiposity similar to activin deficient mice. Objective: Here, we sought to determine the primary effects of adipocyte-selective reduction of Smad2 or Smad3 individually and in combination, on diet-induced adiposity and to establish whether preadipocytes isolated from subcutaneous and visceral white adipose tissues differ in their differentiation capacity. We also assessed the role of activins on cell proliferation and differentiation using an in vitro model. Research Design: To assess the adipose-selective requirements of Smad2, Smad3 and Smad2/3, we generated three lines of adipose-selective conditional knockout (cKO) mice including Smad2cKO, Smad3cKO, and Smad2/3 double cKO mice using Smad2 and/or Smad3 “floxed” mice intercrossed with Adiponectin-Cre mice. Additionally, we isolated preadipocytes and examined adipogenic activity of visceral and subcutaneous preadipocyte and the effects of activin on preadipocyte proliferation and differentiation in vitro. Furthermore, we used mouse embryonic fibroblasts (MEFs) from wild type mice and activin double knockout mice to study the cell autonomous role of activin on differentiation and cell fate. Results: Our results demonstrated that subcutaneous preadipocytes differentiate uniformly and almost all wildtype subcutaneous preadipocytes differentiated into mature adipocytes. In contrast, visceral preadipocytes differentiated poorly. Exogenous activin A promoted proliferation and suppressed differentiation of subcutaneous preadipocytes more robustly given that visceral adipocytes differentiate poorly at baseline. Additionally, global knockout of activin A and B promoted differentiation and browning in differentiated MEFs in vitro consistent with in vivo studies. Furthermore, we showed that Smad2cKO mice did not exhibit significant effects on weight gain, irrespective of diet, whereas Smad3cKO male mice displayed a trend of reduced body weight on high fat diet. On both (LFD and HFD) diets, Smad3cKO male mice displayed an adipose depot-selective phenotype, with significant reduction in subcutaneous fat mass but not visceral fat mass. Smad2/3cKO male mice did not show any difference in body weight or fat mass compared to control mice. Female mice with adipose-selective combined deletion of Smad2/3, displayed reduced body weight and reduction of fat mass in both visceral and subcutaneous depot with higher metabolic rate on HFD compared to control littermates. Conclusions: Our study demonstrated that Smad3 is an important contributor to the development and/or maintenance of subcutaneous white adipose tissue in a sex-selective fashion. Combined reduction of Smad2/3 protects female mice from diet induced obesity and is important for visceral and subcutaneous depots in a sex-selective fashion. These findings have implications for understanding SMAD-mediated, depot selective regulation of adipocyte growth and differentiation. Activin treatment promoted proliferation of preadipocytes, while activin deficiency promoted differentiation and altered the phenotypic characteristics of White adipocytes to brown-like cells in vitro consistent with in vivo.

scholarly journals The Role of Peptide Hormones Discovered in the 21st Century in the Regulation of Adipose Tissue Functions

Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 756
Author(s):  
Paweł A. Kołodziejski ◽  
Ewa Pruszyńska-Oszmałek ◽  
Tatiana Wojciechowicz ◽  
Maciej Sassek ◽  
Natalia Leciejewska ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Energy Expenditure ◽  
21St Century ◽  
Energy Homeostasis ◽  
Peptide Hormones ◽  
Brown Adipose ◽  
Homeostasis Regulation

Peptide hormones play a prominent role in controlling energy homeostasis and metabolism. They have been implicated in controlling appetite, the function of the gastrointestinal and cardiovascular systems, energy expenditure, and reproduction. Furthermore, there is growing evidence indicating that peptide hormones and their receptors contribute to energy homeostasis regulation by interacting with white and brown adipose tissue. In this article, we review and discuss the literature addressing the role of selected peptide hormones discovered in the 21st century (adropin, apelin, elabela, irisin, kisspeptin, MOTS-c, phoenixin, spexin, and neuropeptides B and W) in controlling white and brown adipogenesis. Furthermore, we elaborate how these hormones control adipose tissue functions in vitro and in vivo.

scholarly journals The Protective Effects of Sulforaphane on High-Fat Diet-Induced Obesity in Mice Through Browning of White Fat

2021 ◽  
Vol 12 ◽  
Author(s):  
Yaoli Liu ◽  
Xiazhou Fu ◽  
Zhiyong Chen ◽  
Tingting Luo ◽  
Chunxia Zhu ◽  
...  
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
Fat Mass ◽  
Mitochondrial Biogenesis ◽  
High Fat Diet ◽  
Tolerance Test ◽  
High Fat ◽  
White Fat

Background: Sulforaphane (SFN), an isothiocyanate naturally occurring in cruciferous vegetables, is a potent indirect antioxidant and a promising agent for the control of metabolic disorder disease. The glucose intolerance and adipogenesis induced by diet in rats was inhibited by SFN. Strategies aimed at induction of brown adipose tissue (BAT) could be a potentially useful way to against obesity. However, in vivo protective effect of SFN against obesity by browning white adipocyte has not been reported. Our present study is aimed at evaluation the efficacy of the SFN against the high-fat induced-obesity mice and investigating the potential mechanism.Methods: High-Fat Diet-induced obese female C57BL/6 mice were intraperitoneally injected with SFN (10 mg/kg) daily. Body weight was recorded every 3 days. 30 days later, glucose tolerance test (GTT) and insulin tolerance test (ITT) were performed. At the end of experiment, fat mass were measured and the adipogenesis as well as browning associated genes expression in white adipose tissue (WAT) were determined by RT-qPCR and western blot. Histological examination of the adipose tissue samples were carried out with hematoxylin–eosin (HE) staining and immunofluorescence staining method. In vitro, pre-adipocytes C3H10T1/2 were treated with SFN to investigate the direct effects on adipogenesis.Results: SFN suppressed HFD-induced body weight gain and reduced the size of fat cells in mice. SFN suppressed the expression of key genes in adipogenesis, inhibited lipid accumulation in C3H10T1/2 cells, increased the expression of brown adipocyte-specific markers and mitochondrial biogenesis in vivo and in vitro, and decreased cellular and mitochondrial oxidative stress. These results suggested that SFN, as a nutritional factor, has great potential role in the battle against obesity by inducing the browning of white fat.Conclusion: SFN could significantly decrease the fat mass, and improve glucose metabolism and increase insulin sensitivity of HFD-induced obese mice by promoting the browning of white fat and enhancing the mitochondrial biogenesis in WAT. Our study proves that SFN could serve as a potential medicine in anti-obesity and related diseases.

scholarly journals Cellular adaptations in fat tissue of exercise-trained miniature swine: role of excess energy intake

2000 ◽  
Vol 88 (3) ◽  
pp. 881-887 ◽  
Author(s):  
Gale B. Carey
Keyword(s):  
Adipose Tissue ◽  
Energy Intake ◽  
Excess Energy ◽  
Fat Tissue ◽  
Cellular Mechanisms ◽  
Miniature Swine ◽  
Extracellular Adenosine

This study examined the influence of energy expenditure and energy intake on cellular mechanisms regulating adipose tissue metabolism. 1 Twenty-four swine were assigned to restricted-fed sedentary, restricted-fed exercise-trained, full-fed sedentary, or full-fed exercise-trained groups. After 3 mo of treatment, adipocytes were isolated and adipocyte size, adenosine A1 receptor characteristics, and lipolytic sensitivity were measured. Swine were infused with epinephrine during which adipose tissue extracellular adenosine, plasma fatty acids, and plasma glycerol were measured. Results revealed that adipocytes isolated from restricted-fed exercised swine had a smaller diameter, a lower number of A1 receptors, and a greater sensitivity to lipolytic stimulation, compared with adipocytes from full-fed exercised swine. Extracellular adenosine levels were transiently increased on infusion of epinephrine in adipose tissue of restricted-fed exercised but not full-fed exercised swine. These results suggest a role for adenosine in explaining the discrepancy between in vitro and in vivo lipolysis findings and underscore the notion that excess energy intake dampens the lipolytic sensitivity of adipocytes to β-agonists and adenosine, even if accompanied by exercise training.

scholarly journals A Critical Role of Activin A in Maturation of Mouse Peritoneal Macrophages in vitro and in vivo

2009 ◽  
Vol 6 (5) ◽  
pp. 387-392 ◽  
Author(s):  
Yinan Wang ◽  
Xueling Cui ◽  
Guixiang Tai ◽  
Jingyan Ge ◽  
Nan Li ◽  
...  
Keyword(s):  
Critical Role ◽  
Peritoneal Macrophages ◽  
Activin A ◽  
Mouse Peritoneal Macrophages

scholarly journals Developmental aspects of adipose tissue in GH receptor and prolactin receptor gene disrupted mice: site-specific effects upon proliferation, differentiation and hormone sensitivity

2006 ◽  
Vol 191 (1) ◽  
pp. 101-111 ◽  
Author(s):  
David J Flint ◽  
Nadine Binart ◽  
Stephanie Boumard ◽  
John J Kopchick ◽  
Paul Kelly
Keyword(s):  
Adipose Tissue ◽  
Receptor Gene ◽  
Metabolic Effects ◽  
Wild Type ◽  
Extrinsic Factors ◽  
Differentiation Potential ◽  
Site Specific ◽  
Proliferation And Differentiation

Direct metabolic effects of GH on adipose tissue are well established, but effects of prolactin (PRL) have been more controversial. Recent studies have demonstrated PRL receptors on adipocytes and effects of PRL on adipose tissue in vitro. The role of GH in adipocyte proliferation and differentiation is also controversial, since GH stimulates adipocyte differentiation in cell lines, whereas it stimulates proliferation but inhibits differentiation of adipocytes in primary cell culture. Using female gene disrupted (ko) mice, we showed that absence of PRL receptors (PRLRko) impaired development of both internal and s.c. adipose tissue, due to reduced numbers of adipocytes, an effect differing from that of reduced food intake, where cell volume is decreased. In contrast, GHRko mice exhibited major decreases in the number of internal adipocytes, whereas s.c. adipocyte numbers were increased, even though body weight was decreased by 40–50%. The changes in adipose tissue in PRLRko mice appeared to be entirely due to extrinsic factors since preadipocytes proliferated and differentiated in similar fashion to wild-type animals in vitro and their response to insulin and isoproterenol was similar to wild-type animals. This contrasted with GHRko mice, where s.c. adipocytes proliferated, differentiated, and responded to hormones in identical fashion to controls, whereas parametrial adipocytes exhibited markedly depressed proliferation and differentiation potential and failed to respond to insulin or noradrenaline. Our results provide in vivo evidence that both GH and PRL stimulate differentiation of adipocytes but that the effects of GH are site specific and induce intrinsic changes in the precursor population, which are retained in vitro.

scholarly journals Critical role of integrin CD11c in splenic dendritic cell capture of missing-self CD47 cells to induce adaptive immunity

2018 ◽  
Vol 115 (26) ◽  
pp. 6786-6791 ◽  
Author(s):  
Jiaxi Wu ◽  
Huaizhu Wu ◽  
Jinping An ◽  
Christie M. Ballantyne ◽  
Jason G. Cyster
Keyword(s):  
Critical Role ◽  
T Cell Proliferation ◽  
Cell Capture ◽  
Antigen Uptake ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
Missing Self

CD11c, also known as integrin alpha X, is the most widely used defining marker for dendritic cells (DCs). CD11c can bind complement iC3b and mediate phagocytosis in vitro, for which it is also referred to as complement receptor 4. However, the functions of this prominent marker protein in DCs, especially in vivo, remain poorly defined. Here, in the process of studying DC activation and immune responses induced by cells lacking self-CD47, we found that DC capture of CD47-deficient cells and DC activation was dependent on the integrin-signaling adaptor Talin1. Specifically, CD11c and its partner Itgb2 were required for DC capture of CD47-deficient cells. CD11b was not necessary for this process but could partially compensate in the absence of CD11c. Mice with DCs lacking Talin1, Itgb2, or CD11c were defective in supporting T-cell proliferation and differentiation induced by CD47-deficient cell associated antigen. These findings establish a critical role for CD11c in DC antigen uptake and activation in vivo. They may also contribute to understanding the functional mechanism of CD47-blockade therapies.

Direct and indirect effects of leptin on preadipocyte proliferation and differentiation

2006 ◽  
Vol 290 (6) ◽  
pp. R1557-R1564 ◽  
Author(s):  
Blair Wagoner ◽  
Dorothy B. Hausman ◽  
Ruth B. S. Harris
Keyword(s):  
Adipose Tissue ◽  
Conditioned Medium ◽  
Indirect Effects ◽  
Leptin Receptor ◽  
Cell Number ◽  
Direct And Indirect Effects ◽  
Sprague Dawley ◽  
Proliferation And Differentiation

Leptin has been shown to reduce body fat in vivo. Adipocytes express the leptin receptor; therefore, it is realistic to expect a direct effect of leptin on adipocyte growth and metabolism. In vitro studies examining the effect of leptin on adipocyte metabolism require supraphysiological doses of the protein to see a decrease in lipogenesis or stimulation of lipolysis, implying an indirect action of leptin. It also is possible that leptin reduces adipose mass by inhibiting preadipocyte proliferation (increase in cell number) and/or differentiation (lipid filling). Thus we determined direct and indirect effects of leptin on preadipocyte proliferation and differentiation in vitro. We tested the effect of leptin (0–500 ng/ml), serum from leptin-infused rats (0.25% by volume), and adipose tissue-conditioned medium from leptin-infused rats (0–30% by volume) on preadipocyte proliferation and differentiation in a primary culture of cells from male Sprague-Dawley rat adipose tissue. Leptin (50 ng/ml) stimulated proliferation of preadipocytes ( P < 0.05), but 250 and 500 ng leptin/ml inhibited proliferation of both preadipocyte and stromal vascular cell fractions ( P < 0.01), as measured by [3H]thymidine incorporation. Serum from leptin-infused rats inhibited proliferation of the adipose and stromal vascular fractions ( P = 0.01), but adipose tissue-conditioned medium had no effect on proliferation of either cell fraction. None of the treatments changed preadipocyte differentiation as measured by sn-glycerophosphate dehydrogenase activity. These results suggest that leptin could inhibit preadipocyte proliferation by modifying release of a factor from tissue other than adipose tissue.

scholarly journals Regulation of TRH neurons and energy homeostasis-related signals under stress

2015 ◽  
Vol 224 (3) ◽  
pp. R139-R159 ◽  
Author(s):  
Patricia Joseph-Bravo ◽  
Lorraine Jaimes-Hoy ◽  
Jean-Louis Charli
Keyword(s):  
Energy Homeostasis ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Cellular Phenotype ◽  
Energy Demands ◽  
Rapid Responses ◽  
Hpt Axis

Energy homeostasis relies on a concerted response of the nervous and endocrine systems to signals evoked by intake, storage, and expenditure of fuels. Glucocorticoids (GCs) and thyroid hormones are involved in meeting immediate energy demands, thus placing the hypothalamo–pituitary–thyroid (HPT) and hypothalamo–pituitary–adrenal axes at a central interface. This review describes the mode of regulation of hypophysiotropic TRHergic neurons and the evidence supporting the concept that they act as metabolic integrators. Emphasis has been be placed on i) the effects of GCs on the modulation of transcription ofTrhin vivoandin vitro, ii) the physiological and molecular mechanisms by which acute or chronic situations of stress and energy demands affect the activity of TRHergic neurons and the HPT axis, and iii) the less explored role of non-hypophysiotropic hypothalamic TRH neurons. The partial evidence gathered so far is indicative of a contrasting involvement of distinct TRH cell types, manifested through variability in cellular phenotype and physiology, including rapid responses to energy demands for thermogenesis or physical activity and nutritional status that may be modified according to stress history.

scholarly journals Notch Signaling Regulates MMP-13 Expression via Runx2 in Chondrocytes

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Di Xiao ◽  
Ruiye Bi ◽  
Xianwen Liu ◽  
Jie Mei ◽  
Nan Jiang ◽  
...  
Keyword(s):  
Notch Signaling ◽  
Chondrocyte Proliferation ◽  
Runx2 Expression ◽  
Over Expression ◽  
Proliferation And Differentiation ◽  
Important Regulator ◽  
Signaling Activation

Abstract Notch signaling is involved in the early onset of osteoarthritis. The aim of this study was to investigate the role of Notch signaling changes during proliferation and differentiation of chondrocyte, and to testify the mechanism of MMP-13 regulation by Notch and Runx2 expression changes during osteoarthritis. In this study, Chondrocytes were isolated from rat knee cartilages. Notch signaling was activated/inhibited by Jagged-1/DAPT. Proliferative capacity of Chondrocytes was analyzed by CCK-8 staining and EdU labeling. ColX, Runx2 and MMP-13 expressions were analyzed as cell differentiation makers. Then, Runx2 gene expression was interfered using lentivirus transfection (RNAi) and was over-expressed by plasmids transfected siRNA in chondrocytes, and MMP-13 expression was analyzed after Jagged-1/DAPT treatment. In vivo, an intra-articular injection of shRunx2 lentivirus followed with Jagged1/DAPT treatments was performed in rats. MMP-13 expression in articular cartilage was detected by immunohistochemistry. Finally, MMP-13 expression changes were analyzed in chondrocytes under IL-1β stimulation. Our findings showed that, CCK-8 staining and EdU labeling revealed suppression of cell proliferation by Notch signaling activation after Jagged-1 treatment in chondrocytes. Promoted differentiation was also observed, characterized by increased expressions of Col X, MMP-13 and Runx2. Meanwhile, Sox9, aggrecan and Col II expressions were down-regulated. The opposite results were observed in Notch signaling inhibited cells by DAPT treatment. In addition, Runx2 RNAi significantly attenuated the ‘regulatory sensitivity’ of Notch signaling on MMP-13 expression both in vitro and in vivo. However, we found there wasn’t significant changes of this ‘regulatory sensitivity’ of Notch signaling after Runx2 over-expression. Under IL-1β circumstance, MMP-13 expression could be reduced by both DAPT treatment and Runx2 RNAi, while Runx2 interference also attenuated the ‘regulatory sensitivity’ of Notch in MMP-13 under IL-1β stimulation. In conclusion, Notch signaling is an important regulator on rat chondrocyte proliferation and differentiation, and this regulatory effect was partially mediated by proper Runx2 expression under both normal and IL-1β circumstances. In the meanwhile, DAPT treatment could effectively suppress expression of MMP-13 stimulated by IL-1 β.

scholarly journals The Fabp4-Cre-Model is Insufficient to Study Hoxc9 Function in Adipose Tissue

Biomedicines ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 184
Author(s):  
Sebastian Dommel ◽  
Claudia Berger ◽  
Anne Kunath ◽  
Matthias Kern ◽  
Martin Gericke ◽  
...  
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
High Fat Diet ◽  
Fat Distribution ◽  
Chow Diet ◽  
Littermate Control ◽  
Male And Female ◽  
Biologically Relevant

Developmental genes are important regulators of fat distribution and adipose tissue (AT) function. In humans, the expression of homeobox c9 (HOXC9) is significantly higher in subcutaneous compared to omental AT and correlates with body fat mass. To gain more mechanistic insights into the role of Hoxc9 in AT, we generated Fabp4-Cre-mediated Hoxc9 knockout mice (ATHoxc9-/-). Male and female ATHoxc9-/- mice were studied together with littermate controls both under chow diet (CD) and high-fat diet (HFD) conditions. Under HFD, only male ATHoxc9-/- mice gained less body weight and exhibited improved glucose tolerance. In both male and female mice, body weight, as well as the parameters of glucose metabolism and AT function were not significantly different between ATHoxc9-/- and littermate control CD fed mice. We found that crossing Hoxc9 floxed mice with Fabp4-Cre mice did not produce a biologically relevant ablation of Hoxc9 in AT. However, we hypothesized that even subtle reductions of the generally low AT Hoxc9 expression may cause the leaner and metabolically healthier phenotype of male HFD-challenged ATHoxc9-/- mice. Different models of in vitro adipogenesis revealed that Hoxc9 expression precedes the expression of Fabp4, suggesting that ablation of Hoxc9 expression in AT needs to be achieved by targeting earlier stages of AT development.

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