Deciphering White Adipose Tissue Heterogeneity

Adipose tissue not only stores energy, but also controls metabolism through secretion of hormones, cytokines, proteins, and microRNAs that affect the function of cells and tissues throughout the body. Adipose tissue is organized into discrete depots throughout the body, and these depots are differentially associated with insulin resistance and increased risk of metabolic disease. In addition to energy-dissipating brown and beige adipocytes, recent lineage tracing studies have demonstrated that individual adipose depots are composed of white adipocytes that are derived from distinct precursor populations, giving rise to distinct subpopulations of energy-storing white adipocytes. In this review, we discuss this developmental and functional heterogeneity of white adipocytes both between and within adipose depots. In particular, we will highlight findings from our recent manuscript in which we find and characterize three major subtypes of white adipocytes. We will discuss these data relating to the differences between subcutaneous and visceral white adipose tissue and in relationship to previous work deciphering adipocyte heterogeneity within adipose tissue depots. Finally, we will discuss the possible implications of adipocyte heterogeneity may have for the understanding of lipodystrophies.

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Comparative analyses of chromatin landscape in white adipose tissue suggest humans may have less beigeing potential than other primates

10.1101/524868 ◽

2019 ◽

Author(s):

Devjanee Swain-Lenz ◽

Alejandro Berrio ◽

Alexias Safi ◽

Gregory E. Crawford ◽

Gregory A. Wray

Keyword(s):

Adipose Tissue ◽

Body Fat ◽

White Adipose Tissue ◽

Sequence Motif ◽

Primary Role ◽

Regulatory Regions ◽

Comparative Analyses ◽

White Adipocytes ◽

Beige Adipocytes

AbstractHumans carry a much larger percentage of body fat than other primates. Despite the central role of adipose tissue in metabolism, little is known about the evolution of white adipose tissue in primates. Phenotypic divergence is often caused by genetic divergence in cis-regulatory regions. We examined the cis-regulatory landscape of fat during human origins by performing comparative analyses of chromatin accessibility in human and chimpanzee adipose tissue using macaque as an outgroup. We find that many cis-regulatory regions that are specifically closed in humans are under positive selection, located near genes involved with lipid metabolism, and contain a short sequence motif involved in the beigeing of fat, the process in which white adipocytes are transdifferentiated into beige adipocytes. While the primary role of white adipocytes is to store lipids, beige adipocytes are thermogeneic. The collective closing of many putative regulatory regions associated with beiging of fat suggests an adaptive mechanism that increases body fat in humans.

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The role of adipose tissue in cancer-associated cachexia

Experimental Biology and Medicine ◽

10.1177/1535370216683282 ◽

2016 ◽

Vol 242 (5) ◽

pp. 473-481 ◽

Cited By ~ 27

Author(s):

Janina A Vaitkus ◽

Francesco S Celi

Keyword(s):

Adipose Tissue ◽

White Adipose Tissue ◽

Negative Energy ◽

The Body ◽

Metabolic Disturbances ◽

Adipose Tissue Depots ◽

Brown Adipose ◽

New Evidence

Adipose tissue (fat) is a heterogeneous organ, both in function and histology, distributed throughout the body. White adipose tissue, responsible for energy storage and more recently found to have endocrine and inflammation-modulatory activities, was historically thought to be the only type of fat present in adult humans. The recent demonstration of functional brown adipose tissue in adults, which is highly metabolic, shifted this paradigm. Additionally, recent studies demonstrate the ability of white adipose tissue to be induced toward the brown adipose phenotype – “beige” or “brite” adipose tissue – in a process referred to as “browning.” While these adipose tissue depots are under investigation in the context of obesity, new evidence suggests a maladaptive role in other metabolic disturbances including cancer-associated cachexia, which is the topic of this review. This syndrome is multifactorial in nature and is an independent factor associated with poor prognosis. Here, we review the contributions of all three adipose depots – white, brown, and beige – to the development and progression of cancer-associated cachexia. Specifically, we focus on the local and systemic processes involving these adipose tissues that lead to increased energy expenditure and sustained negative energy balance. We highlight key findings from both animal and human studies and discuss areas within the field that need further exploration. Impact statement Cancer-associated cachexia (CAC) is a complex, multifactorial syndrome that negatively impacts patient quality of live and prognosis. This work reviews a component of CAC that lacks prior discussion: adipose tissue contributions. Uniquely, it discusses all three types of adipose tissue, white, beige, and brown, their interactions, and their contributions to the development and progression of CAC. Summarizing key bench and clinical studies, it provides information that will be useful to both basic and clinical researchers in designing experiments, studies, and clinical trials.

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D-Mannitol Induces a Brown Fat-like Phenotype via a β3-Adrenergic Receptor-Dependent Mechanism

Cells ◽

10.3390/cells10040768 ◽

2021 ◽

Vol 10 (4) ◽

pp. 768

Author(s):

Hui-Jeon Jeon ◽

Dong Kyu Choi ◽

JaeHeon Choi ◽

Seul Lee ◽

Heejin Lee ◽

...

Keyword(s):

Body Weight ◽

Adipose Tissue ◽

Lipid Metabolism ◽

Protein Kinase ◽

White Adipose Tissue ◽

Adrenergic Receptor ◽

Uncoupling Protein ◽

The Body ◽

Brown Fat ◽

White Adipocytes

The presence of brown adipocytes within white adipose tissue is associated with phenotypes that exhibit improved metabolism and proper body weight maintenance. Therefore, a variety of dietary agents that facilitate the browning of white adipocytes have been investigated. In this study, we screened a natural product library comprising 133 compounds with the potential to promote the browning of white adipocytes, and found that D-mannitol induces the browning of 3T3-L1 adipocytes by enhancing the expression of brown fat-specific genes and proteins, and upregulating lipid metabolism markers. D-mannitol also increased the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase 1 (ACC), suggesting a possible role in lipolysis and fat oxidation. Moreover, an increase in the expression of genes associated with D-mannitol-induced browning was strongly correlated with the activation of the β3-adrenergic receptor as well as AMPK, protein kinase A (PKA), and PPARγ coactivator 1α (PGC1α). D-mannitol effectively reduced the body weight of mice fed a high-fat diet, and increased the expression of β1-oxidation and energy expenditure markers, such as Cidea, carnitine palmityl transferase 1 (CPT1), uncoupling protein 1 (UCP1), PGC1α, and acyl-coenzyme A oxidase (ACOX1) in the inguinal white adipose tissue. Our findings suggest that D-mannitol plays a dual regulatory role by inducing the generation of a brown fat-like phenotype and enhancing lipid metabolism. These results indicate that D-mannitol can function as an anti-obesity supplement.

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Angiotensin type 2 receptor activation promotes browning of white adipose tissue and brown adipogenesis

Signal Transduction and Targeted Therapy ◽

10.1038/sigtrans.2017.22 ◽

2017 ◽

Vol 2 (1) ◽

Cited By ~ 21

Author(s):

Aung Than ◽

Shaohai Xu ◽

Ru Li ◽

MelvinKhee-Shing Leow ◽

Lei Sun ◽

...

Keyword(s):

Adipose Tissue ◽

White Adipose Tissue ◽

Receptor Activation ◽

White Adipocytes ◽

Brown Adipose ◽

Beige Adipocytes ◽

Angiotensin Type 2 Receptor ◽

Angiotensin Type ◽

Brown Adipogenesis

Abstract Brown adipose tissue dissipates energy in the form of heat. Recent studies have shown that adult humans possess both classical brown and beige adipocytes (brown-like adipocytes in white adipose tissue, WAT), and stimulating brown and beige adipocyte formation can be a new avenue to treat obesity. Angiotensin II (AngII) is a peptide hormone that plays important roles in energy metabolism via its angiotensin type 1 or type 2 receptors (AT1R and AT2R). Adipose tissue is a major source of AngII and expresses both types of its receptors, implying the autocrine and paracrine role of AngII in regulating adipose functions and self-remodeling. Here, based on the in vitro studies on primary cultures of mouse white adipocytes, we report that, AT2R activation, either by AngII or AT2R agonist (C21), induces white adipocyte browning, by increasing PPARγ expression, at least in part, via ERK1/2, PI3kinase/Akt and AMPK signaling pathways. It is also found that AngII–AT2R enhances brown adipogenesis. In the in vivo studies on mice, administration of AT1R antagonist (ZD7155) or AT2R agonist (C21) leads to the increase of WAT browning, body temperature and serum adiponectin, as well as the decrease of WAT mass and the serum levels of TNFα, triglycerides and free fatty acids. In addition, AT2R-induced browning effect is also observed in human white adipocytes, as evidenced by the increased UCP1 expression and oxygen consumption. Finally, we provide evidence that AT2R plays important roles in hormone T3-induced white adipose browning. This study, for the first time, reveals the browning and brown adipogenic effects of AT2R and suggests a potential therapeutic target to combat obesity and related metabolic disorders.

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Hormonal factors in the control of the browning of white adipose tissue

Hormone Molecular Biology and Clinical Investigation ◽

10.1515/hmbci-2017-0017 ◽

2017 ◽

Vol 31 (1) ◽

Cited By ~ 8

Author(s):

Jiamiao Hu ◽

Mark Christian

Keyword(s):

Adipose Tissue ◽

Brown Adipose Tissue ◽

White Adipose Tissue ◽

Direct Effects ◽

Hormonal Factors ◽

White Adipocytes ◽

Brown Adipose ◽

Beige Adipocytes ◽

Treatment Of Obesity ◽

The Impact

AbstractAdipose tissue has been historically classified into anabolic white adipose tissue (WAT) and catabolic brown adipose tissue (BAT). Recent studies have revealed the plasticity of WAT, where white adipocytes can be induced into ‘brown-like’ heat-producing adipocytes (BRITE or beige adipocytes). Recruiting and activating BRITE adipocytes in WAT (so-called ‘browning’) is believed to provide new avenues for the treatment of obesity-related diseases. A number of hormonal factors have been found to regulate BRITE adipose development and activity through autocrine, paracrine and systemic mechanisms. In this mini-review we will discuss the impact of these factors on the browning process, especially those hormonal factors identified with direct effects on white adipocytes.

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Enhancement of the Antiobesity and Antioxidant Effect of Purple Sweet Potato Extracts and Enhancement of the Effects by Fermentation

Antioxidants ◽

10.3390/antiox10060888 ◽

2021 ◽

Vol 10 (6) ◽

pp. 888

Author(s):

Seul Gi Lee ◽

Jongbeom Chae ◽

Dong Se Kim ◽

Jung-Bok Lee ◽

Gi-Seok Kwon ◽

...

Keyword(s):

Sweet Potato ◽

Ipomoea Batatas ◽

Radical Scavenging ◽

The Body ◽

Brown Adipocyte ◽

Obese Mice ◽

Adipose Tissues ◽

White Adipocytes ◽

Beige Adipocytes ◽

Purple Sweet Potato

The browning of white adipocytes, which transforms energy-storing white adipocytes to heat-producing beige adipocytes, is considered a strategy against metabolic diseases. Several dietary compounds, such as anthocyanins, flavonoids, and phenolic acids, induce a brown adipocyte-like phenotype in white adipocytes. In this study, we demonstrated that purple sweet potato (Ipomoea batatas) extract (PSP) exhibited potent radical scavenging activity. In addition, PSP was found to contain large amounts of phenolic, flavonoid, and anthocyanin compounds; the amount of these compounds was affected by fermentation. Functionally, PSP-induced adipose browning in high-fat-diet (HFD)-induced obese mice. The administration of PSP significantly suppressed the body weight gain and abnormal expansion of white adipose tissues in the obese mice. The expression of adipose browning-related genes was higher in the inguinal white adipose tissues from the PSP-treated mice than those in the HFD-fed mice. Moreover, PSP-treated 3T3-L1 adipocytes formed multilocular lipid droplets, similar to those formed in the 3T3-L1 adipocytes treated with a browning induction cocktail. The PSP-treated cells had an increased expression level of mitochondria and lipolysis-related genes. The browning effects of PSP were enhanced by fermentation with Lactobacillus. This study, to our knowledge, is the first to identify a new mechanism to increase the antiobesity effects of PSP by inducing adipocyte browning of adipocytes.

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Irisin induces white adipose tissue browning in mice as assessed by magnetic resonance imaging

Experimental Biology and Medicine ◽

10.1177/15353702211006049 ◽

2021 ◽

pp. 153537022110060

Author(s):

Yue Chen ◽

Jie Ding ◽

Yufei Zhao ◽

Shenghong Ju ◽

Hui Mao ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Adipose Tissue ◽

Magnetic Resonance ◽

White Adipose Tissue ◽

High Fat Diet ◽

Chow Diet ◽

Resonance Imaging ◽

High Fat ◽

White Adipocytes ◽

Fat Fraction

This study aimed to track and evaluate the effect of low-dose irisin on the browning of white adipose tissue (WAT) in mice using magnetic resonance imaging (MRI) noninvasively in vivo. Mature white adipocytes extracted from mice were cultured, induced and characterized before being treated by irisin. The volume and fat fraction of WAT were quantified using MRI in normal chow diet and high fat mice after injection of irisin. The browning of cultured white adipocytes and WAT in mice were validated by immunohistochemistry and western blotting for uncoupling protein 1 (UCP1) and deiodinase type II (DIO2). The serum indexes were examined with high fat diet after irisin intervention. UCP1 and DIO2 in adipocytes showed increases responding to the irisin treatment. The size of white adipocytes in mice receiving irisin intervention was reduced. MRI measured volumes and fat fraction of WAT were significantly lower after Irisin treatment. Blood glucose and cholesterol levels were reduced in high fat diet mice after irisin treatment. Irisin intervention exerted browning of WAT, resulting reduction of volume and fat fraction of WAT as measured by MRI. Furthermore, it improved the condition of mice with diet-induced obesity and related metabolic disorders.

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Orphan GPR116 mediates the insulin sensitizing effects of the hepatokine FNDC4 in adipose tissue

Nature Communications ◽

10.1038/s41467-021-22579-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Anastasia Georgiadi ◽

Valeria Lopez-Salazar ◽

Rabih El- Merahbi ◽

Rhoda Anane Karikari ◽

Xiaochuan Ma ◽

...

Keyword(s):

Adipose Tissue ◽

White Adipose Tissue ◽

Dependent Manner ◽

Metabolic Dysfunction ◽

Functional Interaction ◽

White Adipocyte ◽

White Adipocytes ◽

Obesity And Diabetes ◽

Adhesion Gpcr ◽

Circulating Levels

AbstractThe proper functional interaction between different tissues represents a key component in systemic metabolic control. Indeed, disruption of endocrine inter-tissue communication is a hallmark of severe metabolic dysfunction in obesity and diabetes. Here, we show that the FNDC4-GPR116, liver-white adipose tissue endocrine axis controls glucose homeostasis. We found that the liver primarily controlled the circulating levels of soluble FNDC4 (sFNDC4) and lowering of the hepatokine FNDC4 led to prediabetes in mice. Further, we identified the orphan adhesion GPCR GPR116 as a receptor of sFNDC4 in the white adipose tissue. Upon direct and high affinity binding of sFNDC4 to GPR116, sFNDC4 promoted insulin signaling and insulin-mediated glucose uptake in white adipocytes. Indeed, supplementation with FcsFNDC4 in prediabetic mice improved glucose tolerance and inflammatory markers in a white-adipocyte selective and GPR116-dependent manner. Of note, the sFNDC4-GPR116, liver-adipose tissue axis was dampened in (pre) diabetic human patients. Thus our findings will now allow for harnessing this endocrine circuit for alternative therapeutic strategies in obesity-related pre-diabetes.

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Contribution of PGC-1α to Obesity- and Caloric Restriction-Related Physiological Changes in White Adipose Tissue

International Journal of Molecular Sciences ◽

10.3390/ijms22116025 ◽

2021 ◽

Vol 22 (11) ◽

pp. 6025

Author(s):

Masaki Kobayashi ◽

Yusuke Deguchi ◽

Yuka Nozaki ◽

Yoshikazu Higami

Keyword(s):

Adipose Tissue ◽

Caloric Restriction ◽

White Adipose Tissue ◽

Mitochondrial Gene ◽

Energy Resource ◽

Peroxisome Proliferator ◽

Physiological Changes ◽

Mitochondrial Gene Expression ◽

Peroxisome Proliferator Activated Receptor ◽

White Adipocytes

Peroxisome proliferator-activated receptor γ coactivator-1 α (PGC-1α) regulates mitochondrial DNA replication and mitochondrial gene expression by interacting with several transcription factors. White adipose tissue (WAT) mainly comprises adipocytes that store triglycerides as an energy resource and secrete adipokines. The characteristics of WAT vary in response to systemic and chronic metabolic alterations, including obesity or caloric restriction. Despite a small amount of mitochondria in white adipocytes, accumulated evidence suggests that mitochondria are strongly related to adipocyte-specific functions, such as adipogenesis and lipogenesis, as well as oxidative metabolism for energy supply. Therefore, PGC-1α is expected to play an important role in WAT. In this review, we provide an overview of the involvement of mitochondria and PGC-1α with obesity- and caloric restriction-related physiological changes in adipocytes and WAT.

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