Thermogenic Genes Research Articles

NG ,NG -Dimethylarginine Dimethylaminohydrolase 1 Expression Is Dispensable for Cold- or Diet-Induced Thermogenesis.

The strategy to activate thermogenic adipocytes has therapeutic potential to overcome obesity as they dissipate surplus energy as heat through various mechanisms. NG,NG-dimethylarginine dimethylaminohydrolases (DDAHs) are enzymes involved in the nitric oxide-protein kinase G signaling axis which increases thermogenic gene expression. However, the role of DDAHs in thermogenic adipocytes has not been elucidated. The adipocyte-specific Ddah1 knockout mice are generated by crossing Ddah1fl/fl mice with adiponectin Cre recombinase mice. Adipocyte-specific DDAH1 overexpressing mice are generated using adeno-associated virus-double-floxed inverse open reading frame (AAV-DIO) system. These mice are analyzed under basal, cold exposure, or high-fat diet (HFD) conditions. Primary inguinal white adipose tissue cells from adipocyte-specific Ddah1 knockout mice expressed comparable amounts of Ucp1 mRNA. Adipocyte-specific DDAH1 overexpressing mice do not exhibit enhanced activation of thermogenic adipocytes. In addition, when these mice are exposed to cold environment or fed an HFD, their body temperature/weight and thermogenesis-related gene and protein expressions are unchanged. These findings indicate that DDAH1 does not play a role in either cold- or diet-induced thermogenesis. Therefore, adipocyte targeting DDAH1 gene therapy for the treatment of obesity is unlikely to be effective.

Ketogenic diet with aerobic exercise can induce fat browning: potential roles of β-hydroxybutyrate.

Despite evidence suggesting that metabolic intermediates like β-HB influence white adipose tissue (WAT) metabolism, the precise molecular mechanisms remain unclear. The aim of this study was to investigate the impact of beta-hydroxybutyrate (β-HB) on the fat browning program and to explore the underlying molecular mechanisms using both in vitro and in vivo models. We assessed the effects of β-HB on fat browning in adipocytes using 3T3-L1 cells and rat models. We evaluated the effects of β-HB on fat browning, thermogenesis, lipid accumulation, adipokine expression, and mitochondrial biogenesis by treating mature 3T3-L1 adipocytes with sodium β-HB for 24 h or by continuously exposing preadipocytes to β-HB during the 8-day differentiation process. Male Sprague Dawley rats were divided into control, exercise only (EX), ketogenic diet only (KD), and combined exercise and ketogenic diet (KE) groups for an 8-week intervention involving diet and/or exercise. After intervention, we evaluated WAT histology, plasma lipids and adipokines, and the expression of markers related to fat browning, thermogenesis and mitochondrial biogenesis in WAT of rats. In our adipocyte culture experiments, β-HB reduced intracellular lipid accumulation by enhancing lipolysis and stimulated the expression of thermogenic and fat browning genes like uncoupling protein 1 (UCP1), PR domain containing 16 (PRDM16), and adipokines such as fibroblast growth factor 21 (FGF21) and Fibronectin type III domain-containing protein 5 (FDNC5). Additionally, β-HB activated the AMPK-SIRT1-PGC-1α pathway, with UCP1 and PRDM16 upregulation mediated by β-HB intracellular action and SIRT1 activity. In animal experiments, KE group raised β-HB levels, decreasing body weight and blood lipids. KD with EX promoted WAT browning possibly via AMPK-SIRT1-PGC-1α, augmenting PRDM16, UCP1, FGF21, and FNDC5 expression. β-HB induction via KD and/or EX shows potential in promoting WAT browning by activating mitochondrial biogenesis, lipolysis, and thermogenesis, suggesting that dietary and physical intervention inducing β-HB may benefit metabolic health.

Aspartate restrains thermogenesis by inhibiting the AMPK pathway in adipose tissues.

Increasing evidence suggests that brown adipose tissue (BAT) plays an important role in obesity and related diseases. Great progress has been made in identifying positive regulators that activate adipocyte thermogenesis, but negative regulatory signaling of thermogenesis remains poorly understood. Here, we evaluated the potential effects of aspartate on the BAT function. We found that the circulating aspartate level is positively associated with metabolic syndrome and obesity in adults. Acute cold exposure significantly increases BAT aspartate as well as other amino acid levels in mice. In this regard, we speculate that aspartate may play a role in regulating the BAT function and systemic energy homeostasis. To verify the hypothesis, we altered aspartate availability to explore the effects on adipose tissue metabolism. Supplementation of aspartate exogenously inhibits the thermogenic gene expression and cold tolerance in mice. Intriguingly, aspartate bioavailability inhibits mitochondrial biosynthesis essentially through the suppression of mechanistic targeting of the AMPK cascade. Therefore, an evaluation of whether a diet deficient in aspartate will increase oxidative phosphorylation in the mitochondria to reestablish aspartate levels and therefore increase the energy expenditure will be interesting because these effects can prevent or ameliorate the development of obesity.

High-fat diet alters the thermogenic gene expression to β-agonists or 18-carbon fatty acids in adipocytes derived from the white and brown adipose tissue of mice

High-fat diet alters the thermogenic gene expression to β-agonists or 18-carbon fatty acids in adipocytes derived from the white and brown adipose tissue of mice

Curcuma xanthorrhiza extract and xanthorrhizol ameliorate cancer-induced adipose wasting in CT26-bearing mice by regulating lipid metabolism and adipose tissue browning

BackgroundCancer cachexia—characterized by anorexia, body weight loss, skeletal muscle atrophy, and fat loss—affects nearly 80% of cancer patients and accounts for 20% of cancer deaths. Curcuma xanthorrhiza, known as Java turmeric, and its active compound xanthorrhizol (XAN) exhibit anticancer, anti-inflammatory, and antioxidant properties. However, the ameliorative effects of C. xanthorrhiza extract (CXE) and XAN on cancer-associated adipose atrophy remain unexplored. This study aimed to evaluate the therapeutic effects of CXE and XAN on cancer cachexia-induced adipose tissue wasting in CT26 tumor-bearing mice. MethodsCT26 cells were injected subcutaneously into the right flank of BALB/c mice to establish a cancer cachexia model. To evaluate the inhibitory effects of CXE and XAN on cancer cachexia, 50 and 100 mg/kg CXE and 15 mg/kg XAN were administered orally every day for 1 week. ResultsCXE and XAN administration significantly attenuated the loss of body weight and epidydimal fat mass by cancer cachexia. In epididymal adipose tissues, administration of CXE or XAN inhibited white adipose tissue browning by repressing expression of the thermogenic genes. Simultaneously, CXE or XAN attenuated fat catabolism through the downregulation of lipolytic genes. The administration of CXE or XAN induced the expression of genes associated with adipogenesis and lipogenesis-related genes. Moreover, CXE or XAN treatment was associated with maintaining metabolic homeostasis; regulating the expression of adipokines and AMP-activated protein kinase (AMPK). ConclusionsCXE and XAN mitigate cancer-induced adipose tissue atrophy, primarily by modulating lipid metabolism and WAT browning, indicating their therapeutic potential for cachectic cancer patients.

Adipose retinol saturase is regulated by β-adrenergic signaling and its deletion impairs lipolysis in adipocytes and acute cold tolerance in mice

ObjectiveRetinol saturase (RetSat) is an endoplasmic reticulum-localized oxidoreductase highly expressed in organs involved in lipid metabolism such as white (WAT) and brown adipose tissue (BAT). Cold exposure was shown to increase RETSAT protein in BAT but its relevance for non-shivering thermogenesis, a process with beneficial effects on metabolic health, is unknown. MethodsWe analyzed the regulation of RetSat expression in white and brown adipocytes and different murine adipose tissue depots upon β-adrenergic stimulation and cold exposure. RetSat function during the differentiation and β-adrenergic stimulation of brown adipocytes was dissected by loss-of-function experiments. Mice with BAT-specific deletion of RetSat were generated and exposed to cold. Gene expression in human WAT was analyzed and the effect of RetSat depletion on adipocyte lipolysis investigated. ResultsWe show that cold exposure induces RetSat expression in both WAT and BAT of mice via β-adrenergic signaling. In brown adipocytes, RetSat has minor effects on differentiation but is required for maximal thermogenic gene and protein expression upon β-adrenergic stimulation and mitochondrial respiration. In mice, BAT-specific deletion of RetSat impaired acute but not long-term adaptation to cold exposure. RetSat expression in subcutaneous WAT of humans correlates with the expression of genes related to mitochondrial function. Mechanistically, we found that RetSat depletion impaired β-agonist-induced lipolysis, a major regulator of thermogenic gene expression in adipocytes. ConclusionsThus, RetSat expression is under β-adrenergic control and determines thermogenic capacity of brown adipocytes and acute cold tolerance in mice. Modulating RetSat activity may allow for therapeutic interventions towards pathologies with inadequate metabolic activity.

GPR84-mediated signal transduction affects metabolic function by promoting brown adipocyte activity.

The G protein-coupled receptor 84 (GPR84), a medium-chain fatty acid receptor, has garnered attention because of its potential involvement in a range of metabolic conditions. However, the precise mechanisms underlying this effect remain elusive. Our study has shed light on the pivotal role of GPR84, revealing its robust expression and functional significance within brown adipose tissue (BAT). Mice lacking GPR84 exhibited increased lipid accumulation in BAT, rendering them more susceptible to cold exposure and displaying reduced BAT activity compared with their WT counterparts. Our in vitro experiments with primary brown adipocytes from GPR84-KO mice revealed diminished expression of thermogenic genes and reduced O2 consumption. Furthermore, the application of the GPR84 agonist 6-n-octylaminouracil (6-OAU) counteracted these effects, effectively reinstating the brown adipocyte activity. These compelling in vivo and in vitro findings converge to highlight mitochondrial dysfunction as the primary cause of BAT anomalies in GPR84-KO mice. The activation of GPR84 induced an increase in intracellular Ca2+ levels, which intricately influenced mitochondrial respiration. By modulating mitochondrial Ca2+ levels and respiration, GPR84 acts as a potent molecule involved in BAT activity. These findings suggest that GPR84 is a potential therapeutic target for invigorating BAT and ameliorating metabolic disorders.

Trim21 Regulates the Postnatal Development and Thermogenesis of Brown Adipose Tissue.

Brown adipose tissue undergoes rapid postnatal development to mature and plays a crucial role in thermoregulation and energy expenditure, which protects against cold and obesity. Herein, it is shown that the expression of Trim21 mRNA level of interscapular brown adipose tissue elevates after birth, and peaks at P14 (postnatal day 14). Trim21 depletion severely impairs the maturation of interscapular brown adipose tissue, decreases the expression of a series of thermogenic genes, and reduces energy expenditure. Consistently, the loss of Trim21 also leads to a suppression of white adipose tissue "browning", in response to cold exposure and a β-adrenergic agonist, CL316,243. In addition, Trim21-/- mice are more prone to high-fat diet-induced obesity compared with the control littermates. Taken together, the study for the first time reveals a critical role of Trim21 in regulating iBAT postnatal development and thermogenesis.

Bisphenol S induces brown adipose tissue whitening and aggravates diet-induced obesity in an estrogen-dependent manner

Bisphenol S (BPS) exposure has been implied epidemiologically to increase obesity risk, but the underlying mechanism is unclear. Here, we propose that BPS exposure at an environmentally relevant dose aggravates diet-induced obesity in female mice by inducing brown adipose tissue (BAT) whitening. We explored the underlying mechanism by which KDM5A-associated demethylation of the trimethylation of lysine 4 on histone H3 (H3K4me3) in thermogenic genes is overactivated in BAT upon BPS exposure, leading to the reduced expression of thermogenic genes. Further studies have suggested that BPS activates KDM5A transcription in BAT by binding to glucocorticoid receptor (GR) in an estrogen-dependent manner. Estrogen-estrogen receptors facilitate the accessibility of the KDM5A gene promoter to BPS-activated GR by recruiting the activator protein 1 (AP-1) complex. These results indicate that BAT is another important target of BPS and that targeting KDM5A-related signals may serve as an approach to counteract the BPS-induced susceptivity to obesity.

A newly identified compound activating UCP1 inhibits obesity and its related metabolic disorders.

Promoting thermogenesis in adipose tissue has been a promising strategy against obesity and related metabolic complications. We aimed to identify compounds that promote thermogenesis in adipocytes and to elucidate their functions and roles in metabolism. To identify compounds that directly promote thermogenesis from a structurally diverse set of 4800 compounds, we utilized a cell-based platform for high-throughput screening that induces uncoupling protein 1 (Ucp1) expression in adipocytes. We identified one candidate compound that activates UCP1. Additional characterization of this compound revealed that it induced cellular thermogenesis in adipocytes with negligible cytotoxicity. In a subsequent diet-induced obesity model, mice treated with this compound exhibited a slower rate of weight gain, improved insulin sensitivity, and increased energy expenditure. Mechanistic studies have revealed that this compound increases mitochondrial biogenesis by elevating maximal respiration, which is partly mediated by the protein kinase A (PKA)-p38 mitogen-activated protein kinase (MAPK) signaling pathway. A further comprehensive genetic analysis of adipocytes treated with these compounds identified two novel UCP1-dependent thermogenic genes, potassium voltage-gated channel subfamily C member 2 (Kcnc2) and predicted gene 5627 (Gm5627). The identified compound can serve as a potential therapeutic drug for the treatment of obesity and its related metabolic disorders. Furthermore, our newly clarified thermogenic genes play an important role in UCP1-dependent thermogenesis in adipocytes.

Foxj3 Regulates Thermogenesis of Brown and Beige Fat Via Induction of PGC-1α.

Enhancing the development and thermogenesis in brown and beige fat represents a potential treatment for obesity. In the present study, we show that Foxj3 expression in fat is stimulated by cold exposure and a β-adrenergic agonist. Adipose-specific Foxj3 knockout impairs the thermogenic function of brown fat, leading to morphological whitening of brown fat and obesity. Adipose Foxj3-deficient mice display increased fasting blood glucose levels and hepatic steatosis on a chow diet. Foxj3 deficiency inhibits the browning of inguinal white adipose tissue (iWAT) following β3-agonist treatment of mice. Furthermore, depletion of Foxj3 in primary brown adipocytes reduces the expression of thermogenic genes and cellular respiration, indicating that the Foxj3 effects on the thermogenic program are cell autonomous. In contrast, Foxj3 overexpression in primary brown adipocytes enhances the thermogenic program. Moreover, AAV-mediated Foxj3 overexpression in brown fat and inguinal WAT increases energy expenditure and improves systemic metabolism on either a chow diet or a high-fat diet. Finally, Foxj3 deletion in fat inhibits the β3 agonist-mediated induction of WAT browning and brown adipose tissue thermogenesis. Mechanistically, cold-inducible Foxj3 stimulates the expression of PGC-1α and UCP1, subsequently promoting energy expenditure. The present study identifies Foxj3 as a critical regulator of fat thermogenesis, and targeting Foxj3 in fat might be a therapeutic strategy for treating obesity and metabolic diseases.

Abstract 19030: Growth Arrest-Specific 5, a Novel Regulator of Adipose Tissue Browning

Background: Obesity is a global epidemic with significant health risks, including type 2 diabetes and cardiovascular diseases. Increasing white adipose tissue (WAT) browning has shown metabolic benefits in both animal models and humans. Long non-coding RNAs (lncRNAs), have been implicated in various diseases, including metabolic disorders. Growth arrest-specific 5 (GAS5), a tumor suppressor lncRNA decreased in type 2 diabetic patients, has been found to be involved in adipocyte differentiation, however, the role of GAS5 in WAT browning has not yet been established. We hypothesized that in the presence of an adipose tissue browning stimuli, GAS5 promotes WAT browning Methods: In vitro approaches through knocking down or overexpressing GAS5 were used to determine its role in regulating thermogenic genes and thermogenesis. To test the role of GAS5 in adipose tissue browning in vivo , adenovirus AAV8 expressing GAS5 was administered specifically in epidydimal adipose tissues followed by the treatment of browning stimuli CL-316,243. Results: Knockdown of GAS5 increased Smad3 phosphorylation, which was blocked by Smad3 inhibitor, SIS3. Conversely, overexpression of GAS5 inhibited Smad3 phosphorylation. On the other hand, Smad3 overexpression blocked the stimulatory effects of GAS5 on the expression of thermogenic genes PGC-1α and UCP1. Moreover, overexpression of GAS5 inhibited, while knockdown of GAS5 enhanced, Smad3 nuclear translocation and tis binding to PGC-1α promoter. In vivo experiments with GAS5 overexpression in epididymal adipose tissues revealed that GAS5 promotes CL-316,243-induced WAT browning in mice. Conclusions: Our study demonstrates that GAS5 promotes WAT browning by suppressing Smad3 signaling, which in turn increases thermogenesis via stimulating PGC-1α and UCP1 expression. These findings establish GAS5 as a novel regulator of WAT browning with potential implications for mitigating obesity and associated metabolic disorders.

GIPR Agonism Enhances TZD-Induced Insulin Sensitivity in Obese IR Mice.

Recent studies have found that GIPR agonism can enhance the metabolic efficacy of GLP-1R agonist treatment by promoting both weight-dependent and -independent improvements on systemic insulin sensitivity. These findings have prompted new investigations aimed at better understanding the broad metabolic benefit of GIPR activation. Herein, we determined whether GIPR agonism favorably influenced the pharmacologic efficacy of the insulin sensitizing thiazolidinedione, rosiglitazone in obese insulin resistant (IR) mice. Genetic and pharmacological approaches were employed to examine the role of GIPR signaling on rosiglitazone-induced weight gain, hyperphagia, and glycemic control. RNA-sequencing was conducted to uncover potential mechanisms by which GIPR activation influences energy balance and insulin sensitivity. In line with previous findings, treatment with rosiglitazone induced the mRNA expression of the GIPR in white and brown fat. However, obese GIPR null mice dosed with rosiglitazone displayed equivalent weight gain to that of wild-type (WT) animals. Strikingly, chronic treatment of obese IR WT animals with a long-acting GIPR agonist (LAGIPRA) prevented rosiglitazone-induced weight-gain and hyperphagia, and it enhanced the insulin-sensitivity effect of this thiazolidinedione. The systemic insulin sensitization was accompanied by increased glucose disposal in brown adipose tissue (BAT), which was underlined by the recruitment of metabolic and thermogenic genes. These findings suggest that GIPR agonism can counter the negative consequences of rosiglitazone treatment on body weight and adiposity, while at the same time improving its insulin sensitizing efficacy.

Pioglitazone-Enhanced Brown Fat Whitening Contributes to Weight Gain in Diet-Induced Obese Mice.

Pioglitazone is an insulin sensitizer used for the treatment of type 2 diabetes mellitus (T2DM) by activating peroxisome proliferator-activated receptor gamma. This study aimed to investigate the effects of pioglitazone on white adipose tissue (WAT) and brown adipose tissue (BAT) in diet-induced obese (DIO) mice. C57BL/6 mice were treated with pioglitazone (30 mg/kg/day) for 4 weeks after a 16-week high-fat diet (HFD) challenge. Body weight gain, body fat mass, energy intake, and glucose homeostasis were measured during or after the treatment. Histopathology was observed by hematoxylin and eosin, oil red O, immunohistochemistry, and immunofluorescence staining. Expression of thermogenic and mitochondrial biogenesis-related genes was detected by quantitative real-time PCR and western blotting. After 4-week pioglitazone treatment, the fasting blood glucose levels, glucose tolerance, and insulin sensitivity were significantly improved, but the body weight gain and fat mass were increased in DIO mice. Compared with the HFD group, pioglitazone did not significantly affect the weights of liver and WAT in both subcutaneous and epididymal regions. Unexpectedly, the weight of BAT was increased after pioglitazone treatment. Histological staining revealed that pioglitazone ameliorated hepatic steatosis, reduced the adipocyte size in WAT, but increased the adipocyte size in BAT. Though pioglitazone can promote lipolysis, thermogenesis, and mitochondrial function in WAT, it leads to impaired thermogenesis, and mitochondrial dysfunction in BAT. In conclusion, pioglitazone could promote the browning of WAT but led to the whitening of BAT; the latter might be a new potential mechanism of pioglitazone-induced weight gain during T2DM treatment.

CXCL13 promotes thermogenesis in mice via recruitment of M2 macrophage and inhibition of inflammation in brown adipose tissue.

Brown adipose tissue (BAT) is mainly responsible for mammalian non-shivering thermogenesis and promotes energy expenditure. Meanwhile, similar to white adipose tissue (WAT), BAT also secretes a variety of adipokines to regulate metabolism through paracrine, autocrine, or endocrine ways. The chemokine C-X-C motif chemokine ligand-13 (CXCL13), a canonical B cell chemokine, functions in inflammation and tumor-related diseases. However, the role of CXCL13 in the adipose tissues is unclear. The expression of CXCL13 in BAT and subcutaneous white adipose tissue (SWAT) of mice under cold stimulation were detected. Local injection of CXCL13 into BAT of normal-diet and high-fat-diet induced obese mice was used to detect thermogenesis and determine cold tolerance. The brown adipocytes were treated with CXCL13 alone or in the presence of macrophages to determine the effects of CXCL13 on thermogenic and inflammation related genes expression in vitro. In this study, we discovered that the expression of CXCL13 in the stromal cells of brown adipose tissue significantly elevated under cold stimulation. Overexpression of CXCL13 in the BAT via local injection could increase energy expenditure and promote thermogenesis in obese mice. Mechanically, CXCL13 could promote thermogenesis via recruiting M2 macrophages in the BAT and, in the meantime, inhibiting pro-inflammatory factor TNFα level. This study revealed the novel role of adipose chemokine CXCL13 in the regulation of BAT activity and thermogenesis.

Cold-inducible lncRNA266 promotes browning and the thermogenic program in white adipose tissue.

Cold-induced nonshivering thermogenesis has contributed to the improvement of several metabolic syndromes caused by obesity. Several long noncoding RNAs (lncRNAs) have been shown to play a role in brown fat biogenesis and thermogenesis. Here we show that the lncRNA lnc266 is induced by cold exposure in inguinal white adipose tissue (iWAT). In vitro functional studies reveal that lnc266 promotes brown adipocyte differentiation and thermogenic gene expression. At room temperature, lnc266 has no effects on white fat browning and systemic energy consumption. However, in a cold environment, lnc266 promotes white fat browning and thermogenic gene expression in obese mice. Moreover, lnc266 increases core body temperature and reduces body weight gain. Mechanistically, lnc266 does not directly regulate Ucp1 expression. Instead, lnc266 sponges miR-16-1-3p and thus abolishes the repression of miR-16-1-3p on Ucp1 expression. As a result, lnc266 promotes preadipocyte differentiation toward brown-like adipocytes and stimulates thermogenic gene expression. Overall, lnc266 is a cold-inducible lncRNA in iWAT, with a key role in white fat browning and the thermogenic program.

SAT667 Follicle-Stimulating Hormone Does Not Directly Regulate Adipogenesis Via The FSH Receptor In Mice

Abstract Disclosure: M. Loka: None. L. Ongaro Gambino: None. T. Uliasz: None. L.A. Jaffe: None. L. Kazak: None. D.J. Bernard: None. Rising rates of obesity are a serious public health challenge. Post-menopausal women are at higher risk of developing obesity and associated comorbidities than premenopausal women, with hormonal changes, such as reduced estrogens, likely to be contributing factors. Menopause is also characterized by increases in pituitary-derived follicle-stimulating hormone (FSH). Recent data suggest that FSH may directly stimulate adipogenesis and block thermogenesis in adipocytes. FSH reportedly decreased expression of thermogenic genes (Cox8b and Ucp1) in murine 3T3-L1 cells differentiated into adipocytes. FSH’s inhibitory effects were no longer apparent in the presence of an FSH-neutralizing antibody. The same FSH antibody reduced fat mass and increased lean mass in ovariectomized (OVX) female mice, a rodent model of menopause. In these studies, it was not established whether FSH acted directly through its canonical receptor (FSHR) in adipocytes to mediate its effects. To address this gap, we differentiated 3T3-L1 cells to adipocytes and treated with FSH. In contrast to the earlier report, FSH did not alter the expression of markers of lipogenesis (Cebpa and Pparg2) or thermogenesis (Cox8b and Ucp1) nor did it impact mitochondrial respiration or lipid accumulation. We also did not detect Fshr mRNA in these cells. We next differentiated the stromal vascular fraction from inguinal adipose tissue of adult male mice into white adipocytes. After 10 days of differentiation, FSH treatment did not alter expression of several markers of adipogenesis and did not affect lipid accumulation. To assess FSH actions in vivo, we generated adipocyte-specific Fshr knockout mice (Fshrfx/fx;Adipoq-Cre, hereafter cKO). Ten-week-old cKO and control female mice were OVX and maintained on standard chow. Eight to 10 weeks later, we performed glucose tolerance and insulin tolerance tests, and determined body composition by EchoMRI. Cre-mediated recombination of the floxed Fshr locus in adipocytes was successful, but did not alter body weight, fat or lean mass, or glucose metabolism in cKO relative to control OVX mice. Furthermore, using a newly developed FSHR-3xHA knockin mouse model, we detected FSHR protein expression in ovary, but not in inguinal and perigonadal white adipose depots or in intrascapular brown adipose tissue. We similarly failed to detect Fshr mRNA in various fat depots in control mice. Collectively, our results fail to show FSH effects on adipogenesis in vitro and challenge the hypothesis that FSH acts through the classical FSHR in adipocytes in vivo. Presentation: Saturday, June 17, 2023

SAT648 The Role Of Olfactory Marker Protein On Adipogenesis

Abstract Disclosure: Y. Bao: None. Y. Cho: None. E. Lee: None. Olfactory marker protein (OMP) plays a role in regulating the of olfactory transduction but is also expressed in adipose tissue. OMP serves as a regulating buffer for cyclic AMP (cAMP) levels; thus, we hypothesized that Omp may play a role in modulating adipocyte differentiation, a cAMP-dependent process. To determine the role of OMP in adipogenesis, we examined the differences in body weight, adipose tissue mass, and adipogenic or thermogenic gene expression of normal and Omp-knockout (KO) mice fed a high-fat diet. The cAMP production, adipogenic gene expression, and cAMP response element binding protein (CREB) phosphorylation were measured during differentiation in 3T3-L1 preadipocytes and mouse embryonic fibroblasts (MEFs). Finally, RNA sequencing was performed to find out why adipogenesis was reduced when Omp was deleted. We observed a decrease in body weight, adipose tissue mass, and the size of adipocytes in Omp-KO mice. We confirmed low cAMP production and CREB phosphorylation in adipogenesis induced in Omp-/- MEFs, and nuclear factor kappa B activation due to significantly reduced IκBα expression. Collectively, our results suggest that loss of OMP function inhibits adipogenesis through affecting adipocyte differentiation. Presentation: Saturday, June 17, 2023

AAV-mediated skeletal muscle specific irisin expression does not contribute to weight loss in mice

Obesity, a chronic disease, significantly increases the risk of various diseases, including diabetes, cardiovascular diseases, and cancers. Exercise is crucial for weight management not only through energy expenditure by muscle activity but also through stimulating the secretion of myokines, which affect various tissues. Irisin, derived from the proteolytic processing of fibronectin type III domain-containing protein 5 (Fndc5), is a well-studied myokine with beneficial effects on metabolism. This study explored the feasibility of adeno-associated virus (AAV)-mediated Fndc5 gene therapy to treat obesity in a mouse model using the AAV-DIO system to express Fndc5 specifically in skeletal muscle, and investigated its anti-obesity effect. Although Fndc5 was specifically expressed in the muscle, no significant impact on body weight under normal chow or high-fat diets was observed, and no change in thermogenic gene expression in inguinal white adipose tissue was detected. Notably, Fndc5 transduction did affect bone metabolism, consistent with previous reports. These findings suggest that AAV-mediated Fndc5 gene therapy may not be an efficient strategy for obesity, contrary to our expectations. Further research is needed to elucidate the complex mechanisms involved in irisin's role in obesity and related disorders.

Mei-Gin Formula Ameliorates Obesity through Lipolysis, Fatty Oxidation, and Thermogenesis in High-Fat Diet-Induced Obese Rats.

Obesity is a metabolic dysfunction characterized by excessive body fat deposition as a consequence of an energy imbalance. Novel therapeutic strategies have emerged that are safe and have comparatively low side effects for obesity treatment. Functional foods and nutraceuticals have recently received a great deal of attention because of their components with the properties of antimetabolic syndrome. Based on our previous in vitro and in vivo investigations on anti-adipogenesis activity and improved body fat accumulation in serials, the combination of three ingredients (including bainiku-ekisu, black garlic, and Mesona procumbens Hemsl), comprising the Mei-Gin formula (MGF), was eventually selected as a novel inhibitor that exhibited preventive effects against obesity. Herein, we verify the anti-obesity effects of MGF in obese rats induced by a high-fat diet and discuss the potential molecular mechanisms underlying obesity development. Oral administration of MGF significantly suppressed the final body weight, weight change, energy and water intake, subcutaneous and visceral fat mass, liver weight, hepatic total lipids and triglycerides (TG), and serum levels of TG, triglycerides (TC), low-density lipoprotein cholesterol (LDL-C), alanine transaminase (AST), uric acid, and ketone bodies and augmented fecal total lipids, TG, and cholesterol excretion in the high-dose MGF-supplemented groups. Furthermore, the corresponding lipid metabolic pathways revealed that MGF supplementation effectively increased lipolysis and fatty acid oxidation gene expression and attenuated fatty acid synthesis gene expression in the white adipose tissue (WAT) and liver and it also increased mitochondrial activation and thermogenic gene expression in the brown adipose tissue (BAT) of rats with obesity induced by a high-fat diet (HFD). These results demonstrate that the intake of MGF can be beneficial for the suppression of HFD-induced obesity in rats through the lipolysis, fatty oxidation, and thermogenesis pathway. In conclusion, these results demonstrate the anti-obesity efficacy of MGF in vivo and suggest that MGF may act as a potential therapeutic agent against obesity.