Differentiation Of 3T3-L1 Cells Research Articles

ACSL1 positively regulates adipogenic differentiation

Aberrant adipogenic differentiation is strongly associated with obesity and related metabolic diseases. Elucidating the key factors driving adipogenesis is an effective strategy for identifying novel therapeutic targets for treating metabolic diseases represented by obesity. In this study, transcriptomic techniques were employed to investigate the functional genes that regulate adipogenic differentiation in OP9 cells and 3T3-L1 cells. The findings indicated a notable upregulation of Acsl1 expression throughout the adipogenic differentiation process. Knocking down Acsl1 led to a decrease in the expression of genes associated with adipogenesis and a reduction in triglyceride accumulation. Additionally, Acsl1 overexpression promoted adipocyte differentiation and adipose-specific overexpression of Acsl1 markedly aggravated steatosis induced by a high-fat diet. Mechanistically, Cyp2f2, Dusp23 and Gstm2 are the crucial genes implicated in Acsl1-induced adipogenic differentiation. The findings of this study indicate that Acsl1 promotes adipogenesis and could serve as a potential therapeutic target for treating obesity and related metabolic disorders.

Potential Anti-Obesity Effect of Hazel Leaf Extract in Mice and Network Pharmacology of Selected Polyphenols

Background: Obesity is gradually becoming a widespread health problem, and treatment using natural compounds has seen an increasing trend. As a by-product of hazelnut, hazel leaf is usually disposed of as waste, but it is widely used in traditional and folk medicines around the world. Aim of this study: Based on previous studies, the effects of the regulation of lipid metabolism and the mechanism of hazel leaf polyphenol extraction obesity were investigated. Methods: In this study, a high-fat diet-fed mouse model of obesity and 3T3-L1 preadipocytes were established. The ameliorative effects of the hazel leaf polyphenol extract on obesity and the regulating lipid metabolisms were explored based on network pharmacology, gut microbiota, and molecular docking. Results: Network pharmacology showed that hazel leaf polyphenols may play a role by targeting key targets, including PPARγ, and regulating the PPAR signaling pathway. They significantly improved body weight gain, the liver index, and adiposity and lipid levels; regulated the gut microbiota and short-chain fatty acid contents; down-regulated the expression of lipid synthesis proteins SREBP1c, PPARγ, and C/EBP-α; and up-regulated the expression of p-AMPK in obese mice. They inhibited the differentiation of 3T3-L1 cells, and the expression of related proteins is consistent with the results in vivo. The molecular docking results indicated that gallic acid, quercetin-3-O-beta-D-glucopyranoside, quercetin, myricetin, and luteolin-7-O-glucoside in the hazel leaf polyphenol extract had strong binding activities with PPARγ, C/EBP-α, and AMPK. Conclusions: The results demonstrate that the hazel leaf polyphenol extract can improve obesity by regulating lipid metabolism, which provides a valuable basis for developing health products made from hazel leaf polyphenols in the future.

7004 Systems genetics analysis to identify candidate genes for fat distribution in BXD mice

Abstract Disclosure: N. Kim: None. D. Ryu: None. C. Oh: None. Obesity is defined as the accumulation of excess fat in the body. Although obesity is the main cause of metabolic disorders, not all obese people have metabolic disorders. Among many factors identified, the ratio of visceral (vWAT) to subcutaneous white adipose tissue (sWAT), representing body fat distribution, has been elucidated to be closely associated with metabolic health. Body fat distribution has been proposed as a possible explanation for this discrepancy. To investigate the regulation of body fat distribution, we performed a genetic analysis using the phenotype data and male subcutaneous fat microarray data from the BXD mouse genetic reference population. Our analysis identified H2-Ke6 (Hsd17b8), encoding hydroxysteroid 17-beta dehydrogenase, as a candidate target for adipose tissue plasticity. To further explore its role, we employed multiple approaches to reveal the effect of Hsd17b8 inhibition. First, lipid accumulation was attenuated in 3T3-L1 preadipocytes where Hsd17b8 was inhibited by CRISPER/Cas9 as well as lasalocid. Furthermore, we confirmed that the expression of adipogenesis-related transcription factor as well as mature adipocyte marker was decreased in terminally differentiated 3T3-L1. Specifically, CCAAT/enchancer binding protein α (Cebpa), peroxisome proliferator-activated receptor γ (Pparg), adiponectin (Adipoq), and fatty acid binding protein 4 (Fabp4) were transcriptionally downregulated. Consistently, in C. elegans, we used RNA interference (RNAi) to inhibit the expression of the Hsd17b8 ortholog, dhs-25, and observed a reduction in lipid accumulation. All these data suggest that the reduction in lipid accumulation in differentiated 3T3-L1 cells by the inhibition of Hsd17b8 is attributed to the suppression of early differentiation during the adipogenesis process. On top of that, to determine whether Hsd17b8 indeed influences body fat distribution in vitro, we utilized IngWAT Mouse Immortalized Preadipocyte Cell Line derived from subcutaneous white adipose tissue (sWAT) of a wild-type mouse. In contrast to the previous findings, we observed an increase in lipid accumulation of IngWAT when Hsd17b8 was inhibited. Surprisingly, the elevation of lipid accumulation in sWAT, as seen in gynoid obesity, has been revealed to be indicative of robust metabolic health compared to android obesity. Collectively, these data suggest that Hsd17b8 may represent a novel therapeutic target for the treatment of obesity. Our study provides valuable insights into the mechanisms underlying metabolic health in obesity and highlights the potential of Hsd17b8 as a therapeutic target for modulating adipose tissue plasticity. Presentation: 6/3/2024

Cleavage and polyadenylation factors are potential regulators of adipogenesis

ObjectiveAlternative polyadenylation (APA) is a co-transcriptional process that leads to isoform diversity in the 3’ ends of mRNAs. APA is known to occur during differentiation, and its dysregulation is observed in diseases like cancer and autoimmune disorders. It has been previously reported that differentiation of 3T3-L1 cells to adipocytes leads to an overall lengthening of mRNAs, but the proteins involved in this regulation have not been identified. The expression levels of subunits of the cleavage and polyadenylation (C/P) complex can regulate the choice of poly(A) site, which in turn can affect different cellular activities. In this paper, we studied the change in levels of C/P proteins during 3T3-L1 differentiation.ResultsWe observed that while the RNA expression of these proteins is unchanged during differentiation, the protein levels of some subunits do change, including a decrease in levels of CPSF73, the nuclease that cuts at the poly(A) site. However, overexpression of CPSF73 alone does not affect the efficiency and rate of differentiation.

Huanglian-Jiedu decoction promotes adipose thermogenesis in obese mice by suppressing the expression of HDAC3

Ethnopharmacological relevanceHuanglian Jiedu Decoction (HLJDD) is an ancient formula of traditional Chinese medicine that is commonly utilized in a range of disorders, and it has been shown to have pharmacological effects on glucose and lipid metabolism. However, the specific mechanism of HLJDD for the treatment of obesity and related metabolic disorders remains to be further investigated. Aim of the studyIt has been thought that encouraging adipose thermogenesis to raise the body's energy expenditure is a useful tactic for improving metabolic abnormalities and losing weight. In this study, we investigated the ability and underlying mechanisms of HLJDD to regulate fat cell thermogenesis to improve energy expenditure in obesity. MethodsThe obese mouse model was established on a high-fat diet for 12 weeks. All mice were divided into NC, HFD, HFD with HLJDD of a low dose (2.25 g/kg/d), and HFD with HLJDD of a high dose (4.5 g/kg/d) groups and kept for 4 weeks. In vitro experiments were conducted to evaluate the effects of 5% and 10% HLJDD-containing serum on differentiated 3T3-L1 cells and HDAC3-knocking-down 3T3-L1 cells. ResultsThe results showed that HLJDD treatment significantly improved glucose and insulin tolerance and decreased the adipocyte radius of WATs, as well as increased energy consumption in obese mice. Besides, HLJDD treatment dramatically increased the levels of thermogenic genes UCP-1 and PGC-1α while suppressing HDAC3 levels in WATs and 3T3-L1 adipocytes. Importantly, the effects of HLJDD on PGC-1α and UCP-1 were blocked in HDAC3 knockdown adipocytes. ConclusionsTherefore, these results suggest that HLJDD enhanced adipose thermogenesis and improved energy expenditure by inhibiting HDAC3, thereby increasing UCP-1 and PGC-1α expression. These findings amplified the mechanisms of HLJDD and its potential to treat obesity and related metabolic disorders.

Depletion of sorting nexin 10 (Snx10) reduces adipocyte differentiation in 3T3-L1 cells

Depletion of sorting nexin 10 (Snx10) reduces adipocyte differentiation in 3T3-L1 cells

Senescence detection using reflected light.

Senescence is an important cellular program occurring in development, tissue repair, cancer, and aging. Increased senescence is also associated with disease states, including obesity and Type 2 diabetes (T2D). Characterizing and quantifying senescent cells at a single cell level has been challenging and particularly difficult in large primary cells, such as human adipocytes. In this study, we present a novel approach that utilizes reflected light for accurate senescence-associated beta-galactosidase (SABG) staining measurements, which can be integrated with immunofluorescence and is compatible with primary mature adipocytes from both human and mouse, as well as with differentiated 3T3-L1 cells. This technique provides a more comprehensive classification of a cell's senescent state by incorporating multiple criteria, including robust sample-specific pH controls. By leveraging the precision of confocal microscopy to detect X-gal crystals using reflected light, we achieved superior sensitivity over traditional brightfield techniques. This strategy allows for the capture of all X-gal precipitates in SABG-stained samples, revealing diverse X-gal staining patterns and improved detection sensitivity. Additionally, we demonstrate that reflected light outperforms western blot analysis for the detection and quantification of senescence in mature human adipocytes, as it offers a more accurate representation of SABG activity. This detection strategy enables a more thorough investigation of senescent cell characteristics and specifically a deeper look at the relationship between adipocyte senescence and obesity associated disorders, such as T2D.

Cynara cardunculus L. inhibits adipogenic differentiation of 3T3-L1 cells via activation of AMPK signaling pathway

Promotion of brown adipose tissue phenotype, able to transform energy into heat, is a promising target against obesity development. We investigated the effects of a standardized extract from Cynara cardunculus L. (CCLE) leaves, considered a waste food resource, on adipogenesis inhibition in 3T3-L1 cells, through the thermogenic process involvement. CCLE inhibited adipogenesis (C/EBPβ, PPAR-γ, FABP4, SREBP-1, and FASN) and increased thermogenesis via upregulation of AMPK phosphorylation. Furthermore, CCLE induced FOXO1 pathway as adipogenesis repressive mechanism affecting PPAR-γ activity and induced the expression of cell cycle inhibitor p21. However, pretreatment with the AMPK inhibitor compound C abolished CCLE effects on FOXO1, p21, C/EBPβ, and PPAR-γ. These data confirmed that the antiadipogenic effect of the extract is related to AMPK activation. Therefore, this work provides new perspectives for the use of this extract in obesity prevention and management. Additionally, reuse/recycling of waste food resources provides added value from a circular economy perspective.

Exercise training-driven exosomal miRNA-323–5p activity suppresses adipogenic conversion of 3T3-L1 cells via the DUSP3/ERK pathway

Adipose-derived stem cell (ASC)-released exosomes (ASCexos) have multiple biological activities. We examined the effect of ASCexos derived from the inguinal adipose tissue of exercise-trained rats (EX-ASCexos) on adipogenic conversion of 3T3-L1 cells and analyzed their microRNA (miRNA) expression profiles. Differentiation of 3T3-L1 cells into adipocytes was performed for 9 d with EX-ASCexos or ASCexos from sedentary control rats (SED-ASCexos), and the expression of proteins and miRNA involved in adipogenic differentiation were determined. EX-ASCexos but not SED-ASCexos attenuated 3T3-L1 adipocyte differentiation with increased phosph-Ser112PPARγ expression, the inactive form of PPARγ. These differentiated adipocytes were also accompanied by increased phosph-Thr202/Tyr204ERK and decreased dual-specificity phosphatase 3 (DUSP3) levels. The exosomal miRNAs miR-323–5p, miR-433–3p, and miR-874–3p were identified specifically in EX-ASCexos. Of these, miR-323–5p mimic replicated the EX-ASCexo-induced suppression of 3T3-L1 adipocyte differentiation and altered adipogenesis-related factor expression. In conclusion, exercise training-driven exosomal miR-323–5p suppressed 3T3-L1 adipogenesis by increasing phosph-Ser112PPARγ expression, while phosph-Thr202/Tyr204ERK accumulation inhibited DUSP3 expression.

Dahuang Huanglian Xiexin Decoction ameliorates obesity via modulating adipocyte differentiation and lipid degradation through inhibiting endoplasmic reticulum stress

Dahuang Huanglian Xiexin Decoction (DHXD) is the representative clinical formula for treating epigastric oppression. In this study, we aim to explore the effect of DHXD on obesity and attempt to investigate its potential mechanism. 3T3-L1 preadipocytes were differentiated and high-fat diet-induced obese rat model was established. DHXD was used for treatment and tunicamycin, the activator of endoplasmic reticulum (ER) stress, was adopted to investigate the related regulatory mechanism. Cell viability was evaluated using CCK-8 assay. Oil-Red O staining was performed to determine lipid accumulation. Glycerol production and Triglyceride content were measured using their commercial kits. Western blot was conducted to examine the expression of critical proteins. Results indicated that DHXD could greatly reduce intracellular lipid droplets and triglyceride in differentiated 3T3-L1 cells. Moreover, the elevated expression of mature adipocytes markers, PPARγ, aP2, during adipogenesis was decreased by DHXD treatment. In addition, DHXD aggravated the lipolysis in differentiated 3T3-L1 cells, as evidenced by the upregulated ATGL expression and the downregulated HSL expression. Besides, DHXD inhibited endoplasmic reticulum (ER) stress in 3T3-L1 cells. Further experiments indicated that the impacts of DHXD on adipocyte differentiation and lipid degradation were partly abolished by tunicamycin. Finally, DHXD alleviated lipid accumulation and ER stress in obese rats. In conclusion, DHXD ameliorates obesity via modulating adipocyte differentiation and lipid degradation through inhibiting ER stress.

70-PUB: Effect of H2O2-Induced Oxidative Stress on Volatile Organic Compounds in Differentiated 3T3-L1 Cells

70-PUB: Effect of H2O2-Induced Oxidative Stress on Volatile Organic Compounds in Differentiated 3T3-L1 Cells

PPA1 promotes adipogenesis by regulating the stability of C/EBPs.

Adipogenesis significantly contributes to healthy adipose tissue expansion in obesity. Increasing adipocyte number or function to alleviate adipose tissue overload could serve as a therapeutic strategy for both lipodystrophy and obesity-related metabolic syndrome. Inorganic pyrophosphatase (PPA1) is an enzyme that catalyzes the hydrolysis of pyrophosphate (PPi) and is involved in many biochemical reactions, but its function in adipose tissue has not been studied previously. In this study, we demonstrated that adipose-specific PPA1 knockout (PPA1AKO) mice showed lipodystrophy and spontaneously developed hepatic steatosis and severe insulin resistance under normal chow diet feeding. PPA1 deficiency suppressed the differentiation of primary adipocyte precursors and 3T3-L1 cells. Notably, PPA1 overexpression can restore inhibited adipogenesis in preadipocytes isolated from db/db mice and type 2 diabetes patients. Mechanistic studies have revealed that PPA1 acts as a positive regulator of early adipocyte differentiation by promoting CCAAT/enhancer-binding proteinβ and δ (C/EBPβ and δ) protein stability. Moreover, the function of PPA1 in adipogenesis is independent of its PPi catalytic activity. Collectively, our in vivo and in vitro findings demonstrated that PPA1 is a novel critical upstream regulator of adipogenesis, controlling adipose tissue development and whole-body metabolic homeostasis.

Lipidomic Assessment of the Inhibitory Effect of Standardized Water Extract of Hydrangea serrata (Thunb.) Ser. Leaves during Adipogenesis.

Obesity is primarily exacerbated by excessive lipid accumulation during adipogenesis, with triacylglycerol (TG) as a major lipid marker. However, as the association between numerous lipid markers and various health conditions has recently been revealed, investigating the lipid metabolism in detail has become necessary. This study investigates the lipid metabolic effects of Hydrangea serrata (Thunb.) Ser. hot water leaf extract (WHS) on adipogenesis using LC-MS-based lipidomics analysis of undifferentiated, differentiated, and WHS-treated differentiated 3T3-L1 cells. WHS treatment effectively suppressed the elevation of glycerolipids, including TG and DG, and prevented a molecular shift in fatty acyl composition towards long-chain unsaturated fatty acids. This shift also impacted glycerophospholipid metabolism. Additionally, WHS stabilized significant lipid markers such as the PC/PE and LPC/PE ratios, SM, and Cer, which are associated with obesity and related comorbidities. This study suggests that WHS could reduce obesity-related risk factors by regulating lipid markers during adipogenesis. This study is the first to assess the underlying lipidomic mechanisms of the adipogenesis-inhibitory effect of WHS, highlighting its potential in developing natural products for treating obesity and related conditions. Our study provides a new strategy for the development of natural products for the treatment of obesity and related diseases.

Effects of Low-Intensity Pulsed Ultrasound on the Regulation of Free Fatty Acid Release in 3T3-L1 Cells.

To investigate the effects of low-intensity pulsed ultrasound (LIPUS) on the proliferation, differentiation, and tumor necrosis factor-α (TNF-α)-induced lipolysis of 3T3-L1 cells, and to explore the feasibility of regulating the release of free fatty acids (FFA) to prevent lipotoxicity. Different intensities (30, 60, 90, and 120 mW/cm2) of LIPUS were applied to 3T3-L1 preadipocytes for different durations (5, 10, 15, 20, 25, and 30 minutes). Appropriate parameters for subsequent experiments were selected by assessing cell viability. The effect of LIPUS on the proliferation and differentiation of 3T3-L1 cells was evaluated by microscope observation, flow cytometry, and lipid content determination. After treated with LIPUS and TNF-α (50 ng/mL), the degree of lipolysis was assessed by measuring the extracellular FFA content. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the mRNA expression of relevant genes. Different parameters of LIPUS significantly enhance the viability of 3T3-L1 cells (P < .05), with 20 minutes and 30 mW/cm2 as the most suitable settings. After LIPUS treatment, 3T3-L1 cell proliferation accelerated, apoptosis rate and G1 phase cell proportion decreased, the content of lipid droplets and TG was increased in differentiated cells, while FFA release decreased (P < .05). The expression of PCNA, PPARγ, C/EBPα, Perilipin A mRNA increased, and the expression of TNF-α, ATGL, HSL mRNA decreased (P < .05). LIPUS could promote the proliferation and differentiation of 3T3-L1 cells and inhibit TNF-α-induced lipolysis, indicating its potential as a therapy for mitigating lipotoxicity caused by decompensated adipocytes.

Development of intestine-targeted microcapsules for enhanced delivery of fucoxanthin: A strategy to mitigate lipid accumulation in vitro and in vivo

The development of intestine-targeted microcapsules using spray drying without maltodextrin is still a challenge. Herein, intestine-targeted fucoxanthin-loaded microcapsules (Fx-MIC) were developed using the spray drying method. The microcapsules were formed by homogenizing fucoxanthin/conjugated linoleic acid (Fx/CLA) and whey protein isolate/Arabic gum (WPI/AG) mixture, followed by spray drying without maltodextrin. The effect of the ratio of Fx/CLA to WPI/AG in Fx-MIC on their morphology and encapsulation efficiency was evaluated. An Fx/CLA-to-WPI/AG ratio of 1:3 yielded a uniform particle size and the highest encapsulation efficiency (91.11%). In vitro simulated digestion demonstrated that Fx-MIC effectively protected Fx from premature release in the stomach and exhibited a release efficiency of 66.08% in the intestine. The digestion product of Fx-MIC effectively inhibited 3T3-L1 cell differentiation and lipid accumulation, demonstrating its ability to reduce lipid accumulation in vitro. Moreover, in high-fat diet (HFD)-induced obesity mice, Fx-MIC exhibited significant reductions in body weight, liver weight, and fat mass. Additionally, Fx-MIC demonstrated notable effects on lowering blood lipid levels and mitigating liver damage. In conclusion, the use of Fx-MIC facilitated the targeted release of Fx, thereby enhancing its anti-obesity effects. This promising result suggests potential applications of Fx-MIC in the food industry.

IL-33 regulates adipogenesis via Wnt/β-catenin/PPAR-γ signaling pathway in preadipocytes

Interleukin-33 (IL-33), an emerging cytokine within the IL-1 family, assumes a pivotal function in the control of obesity. However, the specific mechanism of its regulation of obesity formation remains unclear. In this study, we found that the expression level of IL-33 increased in visceral adipose tissue in mice fed with a high-fat diet (HFD) compared with that in mice fed with a normal diet (ND). In vitro, we also found the expression level of IL-33 was upregulated during the adipogenesis of 3T3-L1 cells. Functional test results showed that knockdown of IL-33 in 3T3-L1 cells differentiation could promote the accumulation of lipid droplets, the content of triglyceride and the expression of adipogenic–related genes (i.e. PPAR-γ, C/EBPα, FABP4, LPL, Adipoq and CD36). In contrast, overexpression of IL-33 inhibits adipogenic differentiation. Meanwhile, the above tests were repeated after over-differentiation of 3T3-L1 cells induced by oleic acid, and the results showed that IL-33 played a more significant role in the regulation of adipogenesis. To explore the mechanism, transcriptome sequencing was performed and results showed that IL-33 regulated the PPAR signaling pathway in 3T3-L1 cells. Further, Western blot and confocal microscopy showed that the inhibition of IL-33 could promote PPAR-γ expression by inhibiting the Wnt/β-catenin signal in 3T3-L1 cells. This study demonstrated that IL-33 was an important regulator of preadipocyte differentiation and inhibited adipogenesis by regulating the Wnt/β-catenin/PPAR-γ signaling pathway, which provided a new insight for further research on IL-33 as a new intervention target for metabolic disorders.

Wounding stress enhances the anti-obesogenic, anti-inflammatory, and antioxidant properties of carrots (Daucuscarota)

This study evaluated the health benefits of carrots (Daucus carota) subjected to post-harvest wounding stress, emphasizing their anti-obesogenic, anti-inflammatory, and antioxidant properties. Carrots were shredded and stored at 15 ± 2 °C for 48 h to induce wounding stress, leading to a significant increase in chlorogenic acid content, by over 112.5 % compared to control. The study utilized 3T3-L1 cell differentiation assays to evaluate the anti-obesogenic potential, monitoring changes in lipid accumulation and adipogenesis-related gene expression. The anti-inflammatory activity was determined in LPS-stimulated RAW 264.7 macrophages by measuring nitrite production, while the antioxidant capacity was assessed using the DCFH-DA assay in Caco-2 cells. Key findings include a notable reduction in lipid accumulation in 3T3-L1 cells with stressed carrot extracts, particularly at 166 μg/mL concentration, showing an 18 % decrease compared to the control. Furthermore, there was a significant alteration in the expression of adipogenesis-related genes, with a 73 % decrease in FAS expression and a 160 % increase in ATGL expression. The stressed carrot extracts at 125 μg/mL also exhibited enhanced anti-inflammatory activity, inhibiting nitrite production by 44.60 %, a 153.26 % increase over the lower concentration. Additionally, antioxidant activity in stressed carrot extracts increased by 77.15 % at 125 μg/mL. These results indicate that wounding stress significantly boosts the health-promoting properties of carrots, suggesting their potential as functional foods for combating obesity and metabolic syndrome-related diseases. The study highlights the value of post-harvest treatments in enhancing the nutraceutical quality of vegetables.

Liraglutide promotes UCP1 expression and lipolysis of adipocytes by promoting the secretion of irisin from skeletal muscle cells

Although Liraglutide (Lira) increases serum irisin levels in type 2 diabetes mellitus (T2DM), it is unclear whether it induces expression of uncoupling protein 1 (UCP1) of adipocytes via promoting irisin secretion from skeletal muscle. Male T2DM rats were treated with 0.4 mg/kg/d Lira twice a day for 8 weeks, and the protein expression of phosphorylated AMP kinase (p-AMPK), phosphorylated acetyl-CoA carboxylase 1 (p-ACC1) and UCP1 in white adipose tissues were detected. Differentiated C2C12 cells were treated with palmitic acid (PA) and Lira to detect the secretion of irisin. Differentiated 3T3-L1 cells were treated with irisin, supernatant from Lira-treated C2C12 cells, Compound C or siAMPKα1, the triglyceride (TG) content and the related gene expression were measured. The transcriptome in irisin-treated differentiated 3T3-L1 cells was analyzed. Lira elevated serum irisin levels, decreased the adipocyte size and increased the protein expression of UCP1, p-AMPK and p-ACC1 in WAT. Moreover, it promoted the expression of PGC1α and FNDC5, the secretion of irisin in PA-treated differentiated C2C12 cells. The irisin and supernatant decreased TG synthesis and promoted the expression of browning- and lipolysis-related genes in differentiated 3T3-L1 cells. While Compound C and siAMPKα1 blocked AMPK activities and expression, irisin partly reversed the pathway. Finally, the transcriptome analysis indicated that differently expressed genes are mainly involved in browning and lipid metabolism. Overall, our findings showed that Lira modulated muscle-to-adipose signaling pathways in diabetes via irisin-mediated AMPKα/ACC1/UCP1/PPARα pathway. Our results suggest a new mechanism for the treatment of T2DM by Lira.

Effects of mifepristone on adipocyte differentiation in mouse 3T3-L1 cells

BackgroundBoth glucocorticoid receptor and peroxisome proliferator-activated receptor-γ (PPARγ) play a critical role in adipocyte differentiation. Mifepristone is not only an antagonist of the glucocorticoid receptor but also an agonist of PPARγ. Therefore, the present study investigated the effect of mifepristone on adipocyte differentiation.MethodsMouse 3T3-L1 cells were used as a model for adipocyte differentiation. The lipid droplet formation was evaluated with Bodipy493/503 staining and the expression of adipocyte markers [adiponectin and adipocyte fatty acid binding protein-4 (Fabp4)] was evaluated with quantitative PCR and immunoblot analyses for indication of adipocyte differentiation. siRNA and neutralizing antibodies were used to elucidate the molecular mechanism of mifepristone-induced adipocyte differentiation. Luciferase reporter assay was used to examine the effect of mifepristone on the promoter activity of PPAR-response element (PPRE). The DNA microarray analysis was used to characterize the transcriptome of the mifepristone-induced adipocytes. In vivo adipogenic effect of mifepristone was examined in mice.ResultsMifepristone not only enhanced adipocyte differentiation induced by the conventional protocol consisting of insulin, dexamethasone and 3-isobutyl-1-methylxanthine but also induced adipocyte differentiation alone, as evidenced by lipid droplets formation and induction of the expression of adiponectin and Fabp4. These effects were inhibited by an adiponectin-neutralizing antibody and a PPARγ antagonist. Mifepristone activated the promoter activity of PPRE in a manner sensitive to PPARγ antagonist. A principal component analysis (PCA) of DNA microarray data revealed that the mifepristone-induced adipocytes represent some characteristics of the in situ adipocytes in normal adipose tissues to a greater extent than those induced by the conventional protocol. Mifepristone administration induced an increase in the weight of epididymal, perirenal and gluteofemoral adipose tissues.ConclusionsMifepristone alone is capable of inducing adipocyte differentiation in 3T3-L1 cells and adipogenesis in vivo. PPARγ plays a critical role in the mifepristone-induced adipocyte differentiation. Mifepristone-induced adipocytes are closer to the in situ adipocytes than those induced by the conventional protocol. The present study proposes a single treatment with mifepristone as a novel protocol to induce more physiologically relevant adipocytes in 3T3-L1 cells than the conventional protocol.

Anti-Obesity Effect of Jeju Roasted Citrus Peel Extract in High-Fat Diet-Induced Obese Mice and 3T3-L1 Adipocytes Via Lipid Metabolism Regulation.

Lipid accumulation in adipocytes occurs through multifactorial effects such as overnutrition due to unbalanced eating habits, reduced physical activity, and genetic factors. In addition, obesity can be intensified by the dis-regulation of various metabolic systems such as differentiation, lipogenesis, lipolysis, and energy metabolism of adipocytes. In this study, the Jeju roasted peel extract from Citrus unshiu S.Markov. (JRC), which is discarded as opposed to the pulp of C. unshiu S.Markov., is commonly consumed to ameliorate obesity. To investigate the anti-obesity effect of JRC, these studies were conducted on differentiated 3T3-L1 cells and in high-fat diet-induced mice, and related methods were used to confirm whether it decreased lipid accumulation in adipocytes. The mechanism of inhibiting obesity by JRC was confirmed through mRNA expression studies. JRC suppressed lipid accumulation in adipocytes and adipose tissue, and significantly improved enzymes such as alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyl transferase and serum lipid profiles. In addition, it effectively modulated the expression of genes related to lipid and energy metabolism in adipose tissue. As a result, these findings suggest that JRC could be a therapeutic regulator of body fat accumulation by significantly alleviating the dis-regulation of intracellular lipid metabolism in adipocytes and by enhancement of energy metabolism (Approval No. CNU IACUC-YB-2023-98).