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

2021 ◽  
Vol 22 (11) ◽  
pp. 6025
Author(s):  
Masaki Kobayashi ◽  
Yusuke Deguchi ◽  
Yuka Nozaki ◽  
Yoshikazu Higami

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.

2006 ◽  
Vol 27 (3) ◽  
pp. 282-294 ◽  
Author(s):  
P. Christopher LaRosa ◽  
Jess Miner ◽  
Yuannan Xia ◽  
You Zhou ◽  
Steve Kachman ◽  
...  

A combined histological and microarray analysis of the white adipose tissue (WAT) of mice fed trans-10, cis-12 conjugated linoleic acid (t10c12 CLA) was performed to better define functional responses. Mice fed t10c12 CLA for 14 days lost 85% of WAT mass, 95% of adipocyte lipid droplet volume, and 15 or 47% of the number of adipocytes and total cells, respectively. Microarray profiling of replicated pools ( n = 2 per day × diet) of control and treated mice ( n = 140) at seven time points after 1–17 days of t10c12 CLA feeding found between 2,682 and 4,216 transcript levels changed by twofold or more. Transcript levels for genes involved in glucose and fatty acid import or biosynthesis were significantly reduced. Highly expressed transcripts for lipases were significantly reduced but still abundant. Increased levels of mRNAs for two key thermogenesis proteins, uncoupling protein 1 and carnitine palmitoyltransferase 1, may have increased energy expenditures. Significant reductions of mRNAs for major adipocyte regulatory factors, including peroxisome proliferator activated receptor-γ, sterol regulatory binding protein 1, CAAT/enhancer binding protein-α, and lipin 1 were correlated with the reduced transcript levels for key metabolic pathways in the WAT. A prolific inflammation response was indicated by the 2- to 100-fold induction of many cytokine transcripts, including those for IL-6, IL-1β, TNF ligands, and CXC family members, and an increased density of macrophages. The mRNA changes suggest that a combination of cell loss, increased energy expenditure, and residual transport of lipids out of the adipocytes may account for the cumulative mass loss observed.


2020 ◽  
Vol 12 (2) ◽  
pp. 85-101
Author(s):  
Anna Meiliana ◽  
Nurrani Mustika Dewi ◽  
Andi Wijaya

BACKGROUND: Obesity has been decades become a highly interest study, accompanied by the realization that adipose tissue (AT) plays a major role in the regulation of metabolic function.CONTENT: In past few years, adipocytes classification, development, and differentiation has been significant changes. The white adipose tissue (WAT) can transform to a phenotype like brown adipose (BAT) type and function. Exercise and cold induction were the most common factor for fat browning; however batokines such as fibroblast growth factor (FGF)-21, interleukin (IL)-6, Slit homolog 2 protein (SLIT2)-C, and Meteorin-like protein (METRNL) perform a beneficial browning action by increasing peroxisome proliferator-activated receptor gamma coactivator (PGC)-1α protein levels, a key factor to stimulate mitochondrial biogenesis and uncoupling Protein 1 (UCP1) transcription, thus change the WAT phenotype into beige.SUMMARY: AT recently known as a complex organ, not only bearing a storage function but as well as the master regulator of energy balance and nutritional homeostasis; brown and beige fat express constitutively high levels of thermogenic genes and raise our expectation on new strategies for fighting obesity and metabolic disorders.KEYWORDS: obesity, white adipose tissue, brown adipose tissue, beige adipose tissue, inflammation, IR, metabolic disease


2020 ◽  
Vol 11 ◽  
Author(s):  
Alexander J. Watts ◽  
Samantha M. Logan ◽  
Anna Kübber-Heiss ◽  
Annika Posautz ◽  
Gabrielle Stalder ◽  
...  

Differential levels of n-6 and n-3 essential polyunsaturated fatty acids (PUFAs) are incorporated into the hibernator’s diet in the fall season preceding prolonged, multi-days bouts of torpor, known as hibernation. Peroxisome proliferator-activated receptor (PPAR) transcriptional activators bind lipids and regulate genes involved in fatty acid transport, beta-oxidation, ketogenesis, and insulin sensitivity; essential processes for survival during torpor. Thus, the DNA-binding activity of PPARα, PPARδ, PPARγ, as well as the levels of PPARγ coactivator 1α (PGC-1α) and L-fatty acid binding protein (L-FABP) were investigated in the hibernating garden dormouse (Eliomys quercinus). We found that dormice were hibernating in a similar way regardless of the n-6/n-3 PUFA diets fed to the animals during the fattening phase prior to hibernation. Further, metabolic rates and body mass loss during hibernation did not differ between dietary groups, despite marked differences in fatty acid profiles observed in white adipose tissue prior and at mid-hibernation. Overall, maintenance of PPAR DNA-binding activity was observed during torpor, and across three n-6/n-3 ratios, suggesting alternate mechanisms for the prioritization of lipid catabolism during torpor. Additionally, while no change was seen in L-FABP, significantly altered levels of PGC-1α were observed within the white adipose tissue and likely contributes to enhanced lipid metabolism when the diet favors n-6 PUFAs, i.e., high n-6/n-3 ratio, in both the torpid and euthermic state. Altogether, the maintenance of lipid metabolism during torpor makes it likely that consistent activity or levels of the investigated proteins are in aid of this metabolic profile.


Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5954
Author(s):  
Kyeong Jo Kim ◽  
Eui-Seon Jeong ◽  
Ki Hoon Lee ◽  
Ju-Ryun Na ◽  
Soyi Park ◽  
...  

Previously, we demonstrated that a 5% ethanol extract of unripe Rubus coreanus (5-uRCK) and ellagic acid has hypocholesterolemic and antiobesity activity, at least partially mediated by the downregulation of adipogenic and lipogenic gene expression in high-fat diet (HFD)-fed animals. The present study investigated the thermogenic and lipolytic antiobesity effects of 5-uRCK and ellagic acid in HFD-induced obese C57BL/6 mice and explored its mechanism of action. Mice fed an HFD received 5-uRCK or ellagic acid as a post-treatment or pretreatment. Both post-treated and pretreated mice showed significant reductions in body weight and adipose tissue mass compared to the HFD-fed mice. The protein levels of lipolysis-associated proteins, such as adipose triglyceride lipase (ATGL), phosphorylated hormone-sensitive lipase (p-HSL), and perilipin1 (PLIN1), were significantly increased in both the 5-uRCK- and ellagic acid-treated mouse epididymal white adipose tissue (eWAT). Additionally, thermogenesis-associated proteins, such as peroxisome proliferator-activated receptor α (PPARα), carnitine palmitoyl transferase-1 (CPT1), uncoupling protein 1 (UCP1), and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α), in inguinal white adipose tissue (ingWAT) were clearly increased in both the 5-uRCK- and ellagic acid-treated mice compared to HFD-fed mice. These results suggest that 5-uRCK and ellagic acid are effective for suppressing body weight gain and enhancing the lipid profile.


2018 ◽  
Vol 19 (11) ◽  
pp. 3335 ◽  
Author(s):  
Masaki Kobayashi ◽  
Namiki Fujii ◽  
Takumi Narita ◽  
Yoshikazu Higami

Caloric restriction (CR) delays the onset of many age-related pathophysiological changes and extends lifespan. White adipose tissue (WAT) is not only a major tissue for energy storage, but also an endocrine tissue that secretes various adipokines. Recent reports have demonstrated that alterations in the characteristics of WAT can impact whole-body metabolism and lifespan. Hence, we hypothesized that functional alterations in WAT may play important roles in the beneficial effects of CR. Previously, using microarray analysis of WAT from CR rats, we found that CR enhances fatty acid (FA) biosynthesis, and identified sterol regulatory element-binding protein 1c (SREBP-1c), a master regulator of FA synthesis, as a mediator of CR. These findings were validated by showing that CR failed to upregulate factors involved in FA biosynthesis and to extend longevity in SREBP-1c knockout mice. Furthermore, we revealed that SREBP-1c is implicated in CR-associated mitochondrial activation through the upregulation of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), a master regulator of mitochondrial biogenesis. Notably, these CR-associated phenotypes were observed only in WAT. We conclude that CR induces SREBP-1c-dependent metabolic remodeling, including the enhancement of FA biosynthesis and mitochondrial activation, via PGC-1α in WAT, resulting in beneficial effects.


2016 ◽  
Vol 310 (1) ◽  
pp. R55-R65 ◽  
Author(s):  
Yun-Hee Lee ◽  
Sang-Nam Kim ◽  
Hyun-Jung Kwon ◽  
Krishna Rao Maddipati ◽  
James G. Granneman

De novo brown adipogenesis involves the proliferation and differentiation of progenitors, yet the mechanisms that guide these events in vivo are poorly understood. We previously demonstrated that treatment with a β3-adrenergic receptor (ADRB3) agonist triggers brown/beige adipogenesis in gonadal white adipose tissue following adipocyte death and clearance by tissue macrophages. The close physical relationship between adipocyte progenitors and tissue macrophages suggested that the macrophages that clear dying adipocytes might generate proadipogenic factors. Flow cytometric analysis of macrophages from mice treated with CL 316,243 identified a subpopulation that contained elevated lipid and expressed CD44. Lipidomic analysis of fluorescence-activated cell sorting-isolated macrophages demonstrated that CD44+ macrophages contained four- to five-fold higher levels of the endogenous peroxisome-proliferator activated receptor gamma (PPARγ) ligands 9-hydroxyoctadecadienoic acid (HODE), and 13-HODE compared with CD44− macrophages. Gene expression profiling and immunohistochemistry demonstrated that ADRB3 agonist treatment upregulated expression of ALOX15, the lipoxygenase responsible for generating 9-HODE and 13-HODE. Using an in vitro model of adipocyte efferocytosis, we found that IL-4-primed tissue macrophages accumulated lipid from dying fat cells and upregulated expression of Alox15. Furthermore, treatment of differentiating adipocytes with 9-HODE and 13-HODE potentiated brown/beige adipogenesis. Collectively, these data indicate that noninflammatory removal of adipocyte remnants and coordinated generation of PPARγ ligands by M2 macrophages provides localized adipogenic signals to support de novo brown/beige adipogenesis.


2005 ◽  
Vol 289 (4) ◽  
pp. E617-E626 ◽  
Author(s):  
Pipeng Li ◽  
Zhengxian Zhu ◽  
Yuyan Lu ◽  
James G. Granneman

Chronic activation of adipocyte β-adrenergic receptors induces remodeling of white adipose tissue (WAT) that includes a transient inflammatory response followed by mitochondrial biogenesis, induction of fatty acid oxidation genes, and elevation of tissue oxidative metabolism. Gene profiling experiments of WAT during remodeling induced by the β3-adrenergic receptor agonist CL-316,243 (CL) suggested that peroxisome proliferator-activated receptor-α (Ppara), which is upregulated by CL, might be an important transcriptional regulator of that process. Histological, physiological, and molecular analysis of CL-induced remodeling in wild-type mice and mice lacking Ppara demonstrated that Ppara was important for inducing adipocyte mitochondrial biogenesis and upregulating genes involved in fatty acid oxidation. Furthermore, Ppara-deficient mice exhibited sustained WAT inflammation during CL treatment, indicating that upregulation of Ppara limits proinflammatory signaling during chronic lipolytic activation. Together, these data support the hypothesis that WAT remodeling is an adaptive response to excessive fatty acid mobilization whereby Ppara and its downstream targets elevate fatty acid catabolism and suppress proinflammatory signaling.


2020 ◽  
Vol 477 (6) ◽  
pp. 1061-1081 ◽  
Author(s):  
Greg L. McKie ◽  
David C. Wright

Our understanding of white adipose tissue (WAT) biochemistry has evolved over the last few decades and it is now clear that WAT is not simply a site of energy storage, but rather a pliable endocrine organ demonstrating dynamic responsiveness to the effects of aerobic exercise. Similar to its established effects in skeletal muscle, aerobic exercise induces many biochemical adaptations in WAT including mitochondrial biogenesis and browning. While past research has focused on the regulation of these biochemical processes, there has been renewed interest as of late given the potential of harnessing WAT mitochondrial biogenesis and browning to treat obesity and type II diabetes. Unfortunately, despite increasing evidence that innumerable factors, both exercise induced and pharmacological, can elicit these biochemical adaptations in WAT, the underlying mechanisms remain poorly defined. Here, we begin with a historical account of our understanding of WAT exercise biochemistry before presenting detailed evidence in favour of an up-to-date model by which aerobic exercise induces mitochondrial biogenesis and browning in WAT. Specifically, we discuss how aerobic exercise induces increases in WAT lipolysis and re-esterification and how this could be a trigger that activates the cellular energy sensor 5′ AMP-activated protein kinase to mediate the induction of mitochondrial biogenesis and browning via the transcriptional co-activator peroxisome proliferator-activated receptor gamma co-activator-1 alpha. While this review primarily focuses on mechanistic results from rodent studies special attention is given to the translation of these results, or lack thereof, to human physiology.


2019 ◽  
Vol 317 (5) ◽  
pp. E751-E759 ◽  
Author(s):  
Roohi Vinaik ◽  
Dalia Barayan ◽  
Abdikarim Abdullahi ◽  
Marc G. Jeschke

A hallmark after burn is the stress and inflammatory-induced hypermetabolic response. Recently, we and others found that browning of white adipose tissue (WAT) is a critical component of this complex detrimental response. Although browning and inflammation have been independently delineated to occur after injury, their interaction is currently not well defined. One of the master regulators of inflammation and adipose tissue remodeling after burns is nucleotide-binding and oligomerization domain, leucine rich repeat and pyrin domain containing 3 (NLRP3) inflammasome. The aim of this this study was to determine whether NLRP3 modulates and activates WAT browning after burn. To obtain molecular and mechanistic insights, we used an NLRP3 knockout (NLRP3−/−) murine burn model. We demonstrated that genetic deletion of NLRP3 promoted persistent and augmented browning in adipocytes, evidenced by increased gene expression of peroxisome proliferator-activated receptor γ and CIDEA at 3 days (5.74 vs. 0.29, P < 0.05; 26.0 vs. 0.71, P < 0.05) and uncoupling protein 1 ( UCP1) and PGC1α at 7 days (7,406 vs. 3,894, P < 0.05; 20.6 vs. 2.52, P < 0.01) and enhanced UCP1 staining and multilocularity. Additionally, the main regulator of postburn WAT browning, IL-6, was elevated in the plasma acutely after burn in NLRP3−/− compared with wild-type counterparts (478.9 vs. 67.1 pg/mL, P < 0.05 at 3 days). These results suggest that NLRP3 has antibrowning effects and that blocking NLRP3 increases thermogenesis and augments browning via increased levels of IL-6. Our findings provide insights into targeting innate inflammatory systems for regulation of adaptive thermogenesis, a critical response after burns and other hypermetabolic conditions.


2018 ◽  
Vol 115 (48) ◽  
pp. 12102-12111 ◽  
Author(s):  
Takeshi Katafuchi ◽  
William L. Holland ◽  
Rahul K. Kollipara ◽  
Ralf Kittler ◽  
David J. Mangelsdorf ◽  
...  

The nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ) is a master regulator of adipocyte differentiation and is the target for the insulin-sensitizing thiazolidinedione (TZD) drugs used to treat type 2 diabetes. In cell-based in vitro studies, the transcriptional activity of PPARγ is inhibited by covalent attachment of small ubiquitin-related modifier (SUMOylation) at K107 in its N terminus. However, whether this posttranslational modification is relevant in vivo remains unclear. Here, using mice homozygous for a mutation (K107R) that prevents SUMOylation at this position, we demonstrate that PPARγ is SUMOylated at K107 in white adipose tissue. We further show that in the context of diet-induced obesity PPARγ-K107R–mutant mice have enhanced insulin sensitivity without the corresponding increase in adiposity that typically accompanies PPARγ activation by TZDs. Accordingly, the PPARγ-K107R mutation was weaker than TZD treatment in stimulating adipocyte differentiation in vitro. Moreover, we found that both the basal and TZD-dependent transcriptomes of inguinal and epididymal white adipose tissue depots were markedly altered in the K107R-mutant mice. We conclude that PPARγ SUMOylation at K107 is physiologically relevant and may serve as a pharmacologic target for uncoupling PPARγ’s beneficial insulin-sensitizing effect from its adverse effect of weight gain.


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