Bola3 Regulates Beige Adipocyte Thermogenesis via Maintaining Mitochondrial Homeostasis and Lipolysis

Mitochondrial iron-sulfur (Fe-S) cluster is an important cofactor for the maturation of Fe-S proteins, which are ubiquitously involved in energy metabolism; however, factors facilitating this process in beige fat have not been established. Here, we identified BolA family member 3 (Bola3), as one of 17 mitochondrial Fe-S cluster assembly genes, was the most significant induced gene in the browning program of white adipose tissue. Using lentiviral-delivered shRNA in vitro, we determined that Bola3 deficiency inhibited thermogenesis activity without affecting lipogenesis in differentiated beige adipocytes. The inhibition effect of Bola3 knockdown might be through impairing mitochondrial homeostasis and lipolysis. This was evidenced by the decreased expression of mitochondria related genes and respiratory chain complexes, attenuated mitochondrial formation, reduced mitochondrial maximal respiration and inhibited isoproterenol-stimulated lipolysis. Furthermore, BOLA3 mRNA levels were higher in human deep neck brown fat than in the paired subcutaneous white fat, and were positively correlated with thermogenesis related genes (UCP1, CIDEA, PRDM16, PPARG, COX7A1, and LIPE) expression in human omental adipose depots. This study demonstrates that Bola3 is associated with adipose tissue oxidative capacity both in mice and human, and it plays an indispensable role in beige adipocyte thermogenesis via maintaining mitochondrial homeostasis and adrenergic signaling-induced lipolysis.

Download Full-text

Beige Fat, Adaptive Thermogenesis, and Its Regulation by Exercise and Thyroid Hormone

Biology ◽

10.3390/biology8030057 ◽

2019 ◽

Vol 8 (3) ◽

pp. 57 ◽

Cited By ~ 6

Author(s):

Kevin J. Phillips

Keyword(s):

Adipose Tissue ◽

Thyroid Hormone ◽

Metabolic Effects ◽

Adipose Tissues ◽

Beige Adipocyte ◽

Adaptive Thermogenesis ◽

Beige Adipocytes ◽

Beige Fat ◽

Beige Cells ◽

Adipocyte Development

While it is now understood that the proper expansion of adipose tissue is critically important for metabolic homeostasis, it is also appreciated that adipose tissues perform far more functions than simply maintaining energy balance. Adipose tissue performs endocrine functions, secreting hormones or adipokines that affect the regulation of extra-adipose tissues, and, under certain conditions, can also be major contributors to energy expenditure and the systemic metabolic rate via the activation of thermogenesis. Adipose thermogenesis takes place in brown and beige adipocytes. While brown adipocytes have been relatively well studied, the study of beige adipocytes has only recently become an area of considerable exploration. Numerous suggestions have been made that beige adipocytes can elicit beneficial metabolic effects on body weight, insulin sensitivity, and lipid levels. However, the potential impact of beige adipocyte thermogenesis on systemic metabolism is not yet clear and an understanding of beige adipocyte development and regulation is also limited. This review will highlight our current understanding of beige adipocytes and select factors that have been reported to elicit the development and activation of thermogenesis in beige cells, with a focus on factors that may represent a link between exercise and ‘beiging’, as well as the role that thyroid hormone signaling plays in beige adipocyte regulation.

Download Full-text

IRX3 Overexpression Enhances Ucp1 Expression In Vivo

Frontiers in Endocrinology ◽

10.3389/fendo.2021.634191 ◽

2021 ◽

Vol 12 ◽

Author(s):

Zhiyin Zhang ◽

Qihan Wu ◽

Yang He ◽

Peng Lu ◽

Danjie Li ◽

...

Keyword(s):

Adipose Tissue ◽

Energy Expenditure ◽

Rna Sequencing ◽

Fat Mass ◽

Moderate Increase ◽

Adipose Tissues ◽

Beige Adipocyte ◽

Beige Adipocytes

ObjectiveThe Iroquois homeobox 3 (IRX3) gene was recently reported to be a functional downstream target of a common polymorphism in the FTO gene, which encodes an obesity-associated protein; however, the role of IRX3 in energy expenditure remains unclear. Studies have revealed that the overexpression of a dominant–negative form of IRX3 in the mouse hypothalamus and adipose tissue promoted energy expenditure by enhancing brown/browning activities. Meanwhile, we and others recently demonstrated that IRX3 knockdown impaired the browning program of primary preadipocytes in vitro. In this study, we aimed to further clarify the effects of overexpressing human IRX3 (hIRX3) on brown/beige adipose tissues in vivo.MethodsBrown/beige adipocyte-specific hIRX3-overexpressing mice were generated and the browning program of white adipose tissues was induced by both chronic cold stimulation and CL316,243 injection. Body weight, fat mass, lean mass, and energy expenditure were measured, while morphological changes and the expression of thermogenesis-related genes in adipose tissue were analyzed. Moreover, the browning capacity of primary preadipocytes derived from hIRX3-overexpressing mice was assessed. RNA sequencing was also employed to investigate the effect of hIRX3 on the expression of thermogenesis-related genes.ResultshIRX3 overexpression in embryonic brown/beige adipose tissues (Rosa26hIRX3;Ucp1-Cre) led to increased energy expenditure, decreased fat mass, and a lean body phenotype. After acute cold exposure or CL316,243 stimulation, brown/beige tissue hIRX3-overexpressing mice showed an increase in Ucp1 expression. Consistent with this, induced hIRX3 overexpression in adult mice (Rosa26hIRX3;Ucp1-CreERT2) also promoted a moderate increase in Ucp1 expression. Ex vitro experiments further revealed that hIRX3 overexpression induced by Ucp1-driven Cre recombinase activity upregulated brown/beige adipocytes Ucp1 expression and oxygen consumption rate (OCR). RNA sequencing analyses indicated that hIRX3 overexpression in brown adipocytes enhanced brown fat cell differentiation, glycolysis, and gluconeogenesis.ConclusionConsistent with the in vitro findings, brown/beige adipocyte-specific overexpression of hIRX3 promoted Ucp1 expression and thermogenesis, while reducing fat mass.

Download Full-text

Differential organ-specific inflammatory response to progranulin in high-fat diet-fed mice

Scientific Reports ◽

10.1038/s41598-020-80940-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Maki Murakoshi ◽

Tomohito Gohda ◽

Eri Adachi ◽

Saki Ichikawa ◽

Shinji Hagiwara ◽

...

Keyword(s):

Adipose Tissue ◽

High Fat Diet ◽

Kidney Injury ◽

Proximal Tubules ◽

Tubular Damage ◽

Standard Diet ◽

Mrna Levels ◽

High Fat ◽

Organ Specific

AbstractProgranulin (PGRN) has been reported to bind tumor necrosis factor (TNF) receptor and to inhibit TNFα signaling. We evaluated the effect of augmentation of TNFα signaling by PGRN deficiency on the progression of kidney injury. Eight-week-old PGRN knockout (KO) and wild-type (WT) mice were fed a standard diet or high-fat diet (HFD) for 12 weeks. Albuminuria, markers of tubular damage, and renal mRNA levels of inflammatory cytokines were higher in HFD-fed KO (KO-HFD) mice than in HFD-fed WT (WT-HFD) mice. Body weight, vacuolization in proximal tubules, and systemic and adipose tissue inflammatory markers were lower in the KO-HFD mice than in the WT-HFD mice. The renal megalin expression was lower in the KO mice than in the WT mice regardless of the diet type. The megalin expression was also reduced in mouse proximal tubule epithelial cells stimulated with TNFα and in those with PGRN knockdown by small interfering RNA in vitro. PGRN deficiency was associated with both exacerbated renal inflammation and decreased systemic inflammation, including that in the adipose tissue of mice with HFD-induced obesity. Improved tubular vacuolization in the KO-HFD mice might partially be explained by the decreased expression of megalin in proximal tubules.

Download Full-text

Maternal obesity during pregnancy leads to adipose tissue ER stress in mice via miR-126-mediated reduction in Lunapark

Diabetologia ◽

10.1007/s00125-020-05357-4 ◽

2021 ◽

Author(s):

Juliana de Almeida-Faria ◽

Daniella E. Duque-Guimarães ◽

Thomas P. Ong ◽

Lucas C. Pantaleão ◽

Asha A. Carpenter ◽

...

Keyword(s):

Adipose Tissue ◽

Glucose Tolerance ◽

Er Stress ◽

Maternal Obesity ◽

Luciferase Assay ◽

Whole Body ◽

Mrna Levels ◽

Protein Levels ◽

Novel Targets

Abstract Aims/hypothesis Levels of the microRNA (miRNA) miR-126-3p are programmed cell-autonomously in visceral adipose tissue of adult offspring born to obese female C57BL/6J mice. The spectrum of miR-126-3p targets and thus the consequences of its dysregulation for adipocyte metabolism are unknown. Therefore, the aim of the current study was to identify novel targets of miR-126-3p in vitro and then establish the outcomes of their dysregulation on adipocyte metabolism in vivo using a well-established maternal obesity mouse model. Methods miR-126-3p overexpression in 3T3-L1 pre-adipocytes followed by pulsed stable isotope labelling by amino acids in culture (pSILAC) was performed to identify novel targets of the miRNA. Well-established bioinformatics algorithms and luciferase assays were then employed to confirm those that were direct targets of miR-126-3p. Selected knockdown experiments were performed in vitro to define the consequences of target dysregulation. Quantitative real-time PCR, immunoblotting, histology, euglycaemic–hyperinsulinaemic clamps and glucose tolerance tests were performed to determine the phenotypic and functional outcomes of maternal programmed miR-126-3p levels in offspring adipose tissue. Results The proteomic approach confirmed the identity of known targets of miR-126-3p (including IRS-1) and identified Lunapark, an endoplasmic reticulum (ER) protein, as a novel one. We confirmed by luciferase assay that Lunapark was a direct target of miR-126-3p. Overexpression of miR-126-3p in vitro led to a reduction in Lunapark protein levels and increased Perk (also known as Eif2ak3) mRNA levels and small interference-RNA mediated knockdown of Lunapark led to increased Xbp1, spliced Xbp1, Chop (also known as Ddit3) and Perk mRNA levels and an ER stress transcriptional response in 3T3-L1 pre-adipocytes. Consistent with the results found in vitro, increased miR-126-3p expression in adipose tissue from adult mouse offspring born to obese dams was accompanied by decreased Lunapark and IRS-1 protein levels and increased markers of ER stress. At the whole-body level the animals displayed glucose intolerance. Conclusions/interpretation Concurrently targeting IRS-1 and Lunapark, a nutritionally programmed increase in miR-126-3p causes adipose tissue insulin resistance and an ER stress response, both of which may contribute to impaired glucose tolerance. These findings provide a novel mechanism by which obesity during pregnancy leads to increased risk of type 2 diabetes in the offspring and therefore identify miR-126-3p as a potential therapeutic target. Graphical abstract

Download Full-text

Betatrophin knockdown induces beiging and mitochondria biogenesis of white adipocytes

Journal of Endocrinology ◽

10.1530/joe-19-0447 ◽

2020 ◽

Vol 245 (1) ◽

pp. 93-100 ◽

Cited By ~ 1

Author(s):

Zhe-Zhen Liao ◽

Xiao-Yan Qi ◽

Ya-Di Wang ◽

Jiao-Yang Li ◽

Qian-Qian Gu ◽

...

Keyword(s):

Signaling Pathway ◽

Ampk Signaling ◽

White Adipocytes ◽

Beige Adipocytes ◽

Beige Fat ◽

Mitochondria Biogenesis ◽

Paracrine Actions ◽

White Fat

Remodeling of energy-storing white fat into energy-consuming beige fat has led to a promising new approach to alleviate adiposity. Several studies have shown adipokines can induce white adipose tissue (WAT) beiging through autocrine or paracrine actions. Betatrophin, a novel adipokine, has been linked to energy expenditure and lipolysis but not clearly clarified. Here, we using high-fat diet-induced obesity to determine how betatrophin modulate beiging and adiposity. We found that betatrophin-knockdown mice displayed less white fat mass and decreased plasma TG and NEFA levels. Consistently, inhibition of betatrophin leads to the phenotype change of adipocytes characterized by increased mitochondria contents, beige adipocytes and mitochondria biogenesis-specific markers both in vivo and in vitro. Of note, blocking AMP-activated protein kinase (AMPK) signaling pathway is able to abolish enhanced beige-like characteristics in betatrophin-knockdown adipocytes. Collectively, downregulation of betatrophin induces beiging in white adipocytes through activation of AMPK signaling pathway. These processes suggest betatrophin as a latent therapeutic target for obesity.

Download Full-text

Adipose tissue-derived neurotrophic factor 3 regulates sympathetic innervation and thermogenesis in adipose tissue

10.1101/2020.06.06.137273 ◽

2020 ◽

Author(s):

Xin Cui ◽

Jia Jing ◽

Rui Wu ◽

Qiang Cao ◽

Fenfen Li ◽

...

Keyword(s):

Adipose Tissue ◽

Neurotrophic Factor ◽

Sympathetic Innervation ◽

Neurite Growth ◽

Sympathetic Neuron ◽

Beige Adipocyte ◽

Diet Induced Obesity ◽

Neurotrophin 3 ◽

Beige Adipocytes ◽

Adipocyte Development

AbstractActivation of brown fat thermogenesis increases energy expenditure and alleviates obesity. Sympathetic nervous system (SNS) is important in brown/beige adipocyte thermogenesis. Here we discover a novel fat-derived “adipokine” neurotrophic factor neurotrophin 3 (NTF3) and its receptor Tropomyosin receptor kinase C (TRKC) as key regulators of SNS growth and innervation in adipose tissue. NTF3 is highly expressed in brown/beige adipocytes, and potently stimulates sympathetic neuron neurite growth. NTF3/TRKC regulates a plethora of pathways in neuronal axonal growth and elongation. Adipose tissue sympathetic innervation is significantly increased in mice with adipocyte-specific NTF3 overexpression, but profoundly reduced in mice with TRKC haploinsufficiency (TRKC+/-). Increasing NTF3 via pharmacological or genetic approach promotes beige adipocyte development, enhances cold-induced thermogenesis and protects against diet-induced obesity (DIO); whereas TRKC+/- mice or SNS TRKC deficient mice are cold intolerant and prone to DIO. Thus, NTF3 is an important fat-derived neurotrophic factor regulating SNS innervation, energy metabolism and obesity.

Download Full-text

Lsd1 prevents age-programed loss of beige adipocytes

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1702641114 ◽

2017 ◽

Vol 114 (20) ◽

pp. 5265-5270 ◽

Cited By ~ 16

Author(s):

Delphine Duteil ◽

Milica Tosic ◽

Dominica Willmann ◽

Anastasia Georgiadi ◽

Toufike Kanouni ◽

...

Keyword(s):

Adipose Tissue ◽

Peroxisome Proliferator ◽

Fat Cell ◽

White Adipocyte ◽

White Adipocytes ◽

Age Related ◽

Beige Adipocytes ◽

Beige Fat ◽

And Function

Aging is accompanied by major changes in adipose tissue distribution and function. In particular, with time, thermogenic-competent beige adipocytes progressively gain a white adipocyte morphology. However, the mechanisms controlling the age-related transition of beige adipocytes to white adipocytes remain unclear. Lysine-specific demethylase 1 (Lsd1) is an epigenetic eraser enzyme positively regulating differentiation and function of adipocytes. Here we show that Lsd1 levels decrease in aging inguinal white adipose tissue concomitantly with beige fat cell decline. Accordingly, adipocyte-specific increase of Lsd1 expression is sufficient to rescue the age-related transition of beige adipocytes to white adipocytes in vivo, whereas loss of Lsd1 precipitates it. Lsd1 maintains beige adipocytes by controlling the expression of peroxisome proliferator-activated receptor α (Ppara), and treatment with a Ppara agonist is sufficient to rescue the loss of beige adipocytes caused by Lsd1 ablation. In summary, our data provide insights into the mechanism controlling the age-related beige-to-white adipocyte transition and identify Lsd1 as a regulator of beige fat cell maintenance.

Download Full-text

The Beige Adipocyte as a Therapy for Metabolic Diseases

International Journal of Molecular Sciences ◽

10.3390/ijms20205058 ◽

2019 ◽

Vol 20 (20) ◽

pp. 5058 ◽

Cited By ~ 16

Author(s):

Fernando Lizcano

Keyword(s):

Diabetes Mellitus ◽

Adipose Tissue ◽

Diabetes Mellitus Type 2 ◽

Metabolic Diseases ◽

Brown Fat ◽

Diabetes Mellitus Type ◽

Beige Adipocyte ◽

Obesity And Diabetes ◽

Beige Adipocytes

Adipose tissue is traditionally categorized into white and brown relating to their function and morphology. The classical white adipose tissue builds up energy in the form of triglycerides and is useful for preventing fatigue during periods of low caloric intake and the brown adipose tissue more energetically active, with a greater number of mitochondria and energy production in the form of heat. Since adult humans possess significant amounts of active brown fat depots and its mass inversely correlates with adiposity, brown fat might play an important role in human obesity and energy homeostasis. New evidence suggests two types of thermogenic adipocytes with distinct developmental and anatomical features: classical brown adipocytes and beige adipocytes. Beige adipocyte has recently attracted special interest because of its ability to dissipate energy and the possible ability to differentiate themselves from white adipocytes. The presence of brown and beige adipocyte in human adults has acquired attention as a possible therapeutic intervention for metabolic diseases. Importantly, adult human brown appears to be mainly composed of beige-like adipocytes, making this cell type an attractive therapeutic target for obesity and obesity-related diseases, such as atherosclerosis, arterial hypertension and diabetes mellitus type 2. Because many epigenetics changes can affect beige adipocyte differentiation from adipose progenitor cells, the knowledge of the circumstances that affect the development of beige adipocyte cells may be important to new pathways in the treatment of metabolic diseases. New molecules have emerged as possible therapeutic targets, which through the impulse to develop beige adipocytes can be useful for clinical studies. In this review will discuss some recent observations arising from the unique physiological capacity of these cells and their possible role as ways to treat obesity and diabetes mellitus type 2.

Download Full-text

Lpin1 in human visceral and subcutaneous adipose tissue: similar levels but different associations with lipogenic and lipolytic genes

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00699.2009 ◽

2010 ◽

Vol 299 (2) ◽

pp. E308-E317 ◽

Cited By ~ 4

Author(s):

Merce Miranda ◽

Xavier Escoté ◽

María J. Alcaide ◽

Esther Solano ◽

Victòria Ceperuelo-Mallafré ◽

...

Keyword(s):

Adipose Tissue ◽

Metabolic Profile ◽

Low Grade ◽

Mrna Levels ◽

Cross Sectional ◽

Expression Of Genes ◽

Close Relationship ◽

Few Data ◽

Vitro Analysis

LPIN1 is a gene with important effects on lipidic and metabolic homeostasis. Human subcutaneous LPIN1 expression levels in adipose tissue are related with a better metabolic profile, including insulin sensitivity markers. However, there are few data on the regulation of LPIN1 in visceral adipose tissue (VAT). Our aim was to perform a cross-sectional analysis of VAT compared with subcutaneous (SAT) LPIN1 expression in a well-characterized obese cohort, its relation with the expression of genes involved in lipid metabolism, and the in vitro response to lipogenic and lipolytic stimuli. A downregulation of total LPIN1 mRNA expression in subjects with obesity was found in VAT similarly to that in SAT. Despite similar total LPIN1 mRNA levels in SAT and VAT, a close relationship with clinical parameters and with many lipogenic and lipolytic genes was observed primarily in SAT depot. As shown in the in vitro analysis, the low-grade proinflammatory environment and the insulin resistance associated with obesity may contribute to downregulate LPIN1 in adipose tissue, leading to a worse metabolic profile.

Download Full-text

Expression of peroxisome proliferator-activated receptors in lean and obese Zucker rats

Acta Endocrinologica ◽

10.1530/eje.0.1420071 ◽

2000 ◽

pp. 71-78 ◽

Cited By ~ 29

Author(s):

A Gorla-Bajszczak ◽

C Siegrist-Kaiser ◽

O Boss ◽

AG Burger ◽

CA Meier

Keyword(s):

Adipose Tissue ◽

Fiber Type ◽

Zucker Rats ◽

Peroxisome Proliferator ◽

Mrna Levels ◽

Rnase Protection ◽

Brown Adipose ◽

Obese Zucker Rats

OBJECTIVE: Examination of the pattern of expression of peroxisome proliferator-activated receptor (PPAR) isoforms alpha and gamma in a model of obesity. DESIGN: Examination of adipose tissue and primary adipocyte cultures from lean and obese Zucker rats at different ages (28 days and 12 weeks). METHODS: mRNA levels were measured by RNase protection assay.RESULTS: The highest levels of PPARalpha and gamma mRNA were present in brown adipose tissue (BAT), followed by liver and white adipose tissue (WAT) for the alpha and gamma subtypes, respectively, at both ages examined. PPARalpha was expressed 100-fold higher in BAT compared with WAT, and PPARgamma mRNA levels were 2-fold higher in the WAT of obese compared with lean rats. PPARalpha and gamma expression was minimal in m. soleus, although higher levels of PPARgamma were found in the diaphragm. In marked contrast to the findings in vivo, virtually no PPARalpha mRNA could be detected in BAT cultures differentiated in vitro. CONCLUSION: PPARalpha and gamma are most highly expressed in BAT in vivo. However, PPARalpha is undetectable in brown adipose cells in vitro, suggesting that the expression of this receptor is induced by some external stimuli. In addition, the expression of PPARgamma was increased in WAT from young obese animals, compatible with an early adaptive phenomenon. Finally, the presence of PPARgamma mRNA is detectable only in particular muscles, such as the diaphragm, suggesting the possibility of an influence of fiber type on its expression, although exercise did not influence the expression of PPARgamma in other skeletal muscles.

Download Full-text