Adipogenic Genes Research Articles

Identification of a novel PPARγ modulator with good anti-diabetic therapeutic index via structure-based screening, optimization and biological validation

PPARγ is well-known as the target receptor of TZD anti-diabetic drugs. However, recently the therapeutic benefits of these TZD drugs have been compromised by many severe side effects because of their full PPARγ agonistic action to lock the AF-2 helix. Herein, we conducted a virtual screening in the combination with structure-based design, synthesis and biological evaluation both in vitro and in vivo, leading to the identification of a potent candidate YG-C-20 as the SPPARγM with improved and safer anti-diabetic therapeutics. Mechanistically, this compound presented such desired pharmacological profiles (e.g., preferable anti-diabetic efficiencies and minimized side effects) mainly via selectively inhibiting the CDK5-mediated phosphorylation of PPARγ-Ser273 and up-regulating the expression of insulin-sensitive genes Adiponectin and Glut4, yet lacking the classical full agonism to induce the adipogenesis and the expression of key adipogenic genes including PPARγ, aP2, CD36, LPL, C/EBPα and FASN. Further validation led to the final recognition of its (R)-configured isomer as the potential conformational form. Subsequent molecular docking studies revealed a unique hydrogen-bonding network of (R)-YG-C-20 with three full PPARγ agonism-unrelated residues, especially with PPARγ-Ser273 phosphorylation-associated site Ser342, which not only gives a clear verification for our structure-based design but also provides a proof of concept for the abovementioned molecular mechanism.

Microbiota modulation and anti-obesity effects of fermented Pyrus ussuriensis Maxim extract against high-fat diet-induced obesity in rats

Pyrus ussuriensis Maxim (Korean pear) has been used for hundreds of years as a traditional herbal medicine due to its strong phytochemical profile and pharmacological efficacy. In this study, we evaluated the anti-obesity potential of Pyrus ussuriensis Maxim extracts (PUE) and investigated the underlying mechanisms using a combination of in vitro, in vivo, and microbiota regulation approaches. In an adipogenesis assay, the fermented (F)PUE and non-fermented (NF)PUE significantly reduced the differentiation of 3T3-L1 preadipocyte in a dose-dependent manner with an IC50 of 85.33 and 96.67 µg/mL, respectively. In a high-fat diet (HFD)-induced obese rat model (n = 8 animals/group), oral administration of FPUE additionally reduced the total body weight gain significantly. No difference in food intake was observed, however, between the control-chow diet, FPUE, and NFPUE-treated HFD rats. Adipose tissue mass and systemic insulin resistance were markedly reduced in FPUE-treated HFD rats, in a dose-dependent manner. Treatment with FPUE also greatly improved obesity-related biomarkers, including total cholesterol, leptin, active ghrelin, Total GIP, adiponectin, and proinflammatory cytokines. Moreover, FPUE significantly suppressed HFD-induced adipogenic genes expression, while increasing fatty acid oxidation-related genes expression. Additionally, FPUE treatment attenuated the HFD-induced Firmicutes proportion within the intestinal microbiota by regulating key metabolic pathways, thus enhancing microbial population diversity (e.g., increasing Bacteroides, Bifidobacterium, Prevotella, Eubacterium, and Clostridium). Together, these results reveal a strong anti-obesity potential of FPUE through adipogenesis, lipid metabolism, weight reduction, and microbiota regulation, raising the possibility of developing FPUE as a novel therapeutic agent to control obesity and obesity-associated metabolic disorders.

Sex-Dependent Role of Adipose Tissue HDAC9 in Diet-Induced Obesity and Metabolic Dysfunction.

Obesity is a major risk factor for both metabolic and cardiovascular disease. We reported that, in obese male mice, histone deacetylase 9 (HDAC9) is upregulated in adipose tissues, and global deletion of HDAC9 protected against high fat diet (HFD)-induced obesity and metabolic disease. Here, we investigated the impact of adipocyte-specific HDAC9 gene deletion on diet-induced obesity in male and female mice. The HDAC9 gene expression was increased in adipose tissues of obese male and female mice and HDAC9 expression correlated positively with body mass index in humans. Interestingly, female, but not male, adipocyte-specific HDAC9 KO mice on HFD exhibited reduced body weight and visceral adipose tissue mass, adipocyte hypertrophy, and improved insulin sensitivity, glucose tolerance and adipogenic differentiation gene expression. Furthermore, adipocyte-specific HDAC9 gene deletion in female mice improved metabolic health as assessed by whole body energy expenditure, oxygen consumption, and adaptive thermogenesis. Mechanistically, compared to female mice, HFD-fed male mice exhibited preferential HDAC9 expression in the stromovascular fraction, which may have offset the impact of adipocyte-specific HDAC9 gene deletion in male mice. These results suggest that HDAC9 expressed in adipocytes is detrimental to obesity in female mice and provides novel evidence of sex-related differences in HDAC9 cellular expression and contribution to obesity-related metabolic disease.

Use of collagenase to isolate adipose tissue-derived stem cells – substantial manipulation or not?

Background: Collagenase is commonly used to isolate the stromal vascular fraction (SVF) or adipose tissue-derived stem cells (ADSCs) from human adipose tissue. Enzymatic breakdowns may be a substantial manipulation according to the classifications of medical regulatory authorities. This study investigates the possible effects of human adipose tissue dissociation with collagenase on in vitro function and behavior of ADSCs. Methods and results: Adipose tissue from nine donors was divided into two equal fractions. SVF was then isolated either mechanically or with collagenase, respectively. The resulting cells were analyzed for their surface markers directly after isolation and at passage five. Proliferation, tri-lineage differentiation, and secretome markers were measured after passage four. Using collagenase compared to mechanical isolation did not alter the expression of typical surface markers of ADSCs. ADSCs isolated with collagenase showed a significantly shorter population doubling time (p < 0.001), a significantly higher mean specific GPDH-activity, a stronger intensity in perilipin staining (p = 0.005), and a significantly higher extracellular calcium deposition (p = 0.006) than mechanically isolated ADSCs. The expression of adipogenic and osteogenic marker genes was not different in mechanically versus enzymatically isolated ADSCs. There were no significant differences in proteoglcyan production (p > 0.05) and the concentration of type 2 collagen. Except for an increased CCL2 concentration in mechanically isolated ASDCs (p = 0.01), there were no significant differences in the concentration of secreted proteins between both isolation methods. Conclusions: The use of collagenase does not substantially impair central in vitro characteristics and functions of human adipose tissue-derived stem cells.

Sargassum thunbergii Extract Attenuates High-Fat Diet-Induced Obesity in Mice by Modulating AMPK Activation and the Gut Microbiota.

Sargassum thunbergii (Mertens ex Roth) Kuntze (ST) is a brown alga rich in indole-2-carboxaldehyde. This study aimed to investigate the anti-obesity effects of ethanol extract from ST in in vitro and in vivo models. In 3T3-L1 cells, ST extract significantly inhibited lipid accumulation in mature adipocytes while lowering adipogenic genes (C/epba and Pparg) and enhancing metabolic sensors (Ampk, Sirt1), thermogenic genes (Pgc-1a, Ucp1), and proteins (p-AMPK/AMPK and UCP1). During animal investigation, mice were administered a chow diet, a high-fat diet (HF), or an HF diet supplemented with ST extract (at dosages of 150 and 300 mg/kg bw per day) for 8 weeks (n = 10/group). ST extract administration decreased weight gain, white adipose tissue weight, LDL-cholesterol, and serum leptin levels while improving glucose intolerance. In addition, ST extract increased the expression of Ampk and Sirt1 in adipose tissue and in the liver, as well as p-AMPK/AMPK ratio in the liver, compared to HF-fed mice. The abundance of Bacteroides vulgatus and Faecalibacterium prausnitzii in the feces increased in response to ST extract administration, although levels of Romboutsia ilealis decreased compared with those in HF-fed mice. ST extract could prevent obesity in HF-fed mice via the modulation of AMPK activation and gut microbiota composition.

Growth hormone inhibits adipogenic differentiation and induces browning in bovine subcutaneous adipocytes

ObjectiveIt is well established that growth hormone (GH) has the ability to stimulate lipolysis. The effects of GH on adipocyte differentiation and browning have not been clearly described. Therefore, the present study aimed to elucidate the role of GH in the differentiation and browning of bovine subcutaneous adipocytes as well as its underlying molecular mechanisms. MethodsWe first treated bovine subcutaneous preadipocytes with different concentrations (0, 10, 100, and 500 ng/mL) of GH for 8 days and measured lipid accumulation and gene expression. Afterward, we treated preadipocytes and mature adipocytes with 500 ng/mL GH and determined differentiation and browning-related indicators. Finally, we investigated the expression of STAT5B in both preadipocytes and mature adipocytes after GH treatment. ResultsWe demonstrated that GH inhibited lipid accumulation and decreased the expression levels of adipogenic key genes (SCD1, SREBP1, PPARγ, and CEBPα) during adipocyte differentiation. Moreover, we observed that the inhibitory effect of GH on the early stage of adipocyte differentiation (0–2 days) was stronger than that on the later stage of adipocyte differentiation (2–8 days). We also found that GH promoted the expression levels of browning-related genes such as uncoupling protein 1 (UCP1) in mature adipocytes. Concurrently, GH promoted mitochondrial biogenesis and increased the expression levels of mitochondrial biogenesis-related genes. In addition, GH promoted phosphorylation of signal transducers and activator of transcription 5 b (STAT5B) and contributed to translocation of STAT5B to nucleus. After blocking the expression of STAT5B protein, GH weakened the inhibition of adipogenic key genes and reduced the promotion of browning-related genes in bovine subcutaneous adipocytes. ConclusionsGH can inhibit adipocyte differentiation and promote adipocyte browning by regulating STAT5B in bovine subcutaneous adipocytes.

The effects of maternal fish oil supplementation rich in n-3 PUFA on offspring-broiler growth performance, body composition and bone microstructure.

This study evaluated the effects of maternal fish oil supplementation rich in n-3 PUFA on the performance and bone health of offspring broilers at embryonic development stage and at market age. Ross 708 broiler breeder hens were fed standard diets containing either 2.3% soybean oil (SO) or fish oil (FO) for 28 days. Their fertilized eggs were collected and hatched. For a pre-hatch study, left tibia samples were collected at 18 days of incubation. For a post-hatch study, a total of 240 male chicks from each maternal treatment were randomly selected and assigned to 12 floor pens and provided with the same broiler diets. At 42 days of age, growth performance, body composition, bone microstructure, and expression of key bone marrow osteogenic and adipogenic genes were evaluated. One-way ANOVA was performed, and means were compared by student’s t-test. Maternal use of FO in breeder hen diet increased bone mineral content (p < 0.01), bone tissue volume (p < 0.05), and bone surface area (p < 0.05), but decreased total porosity volume (p < 0.01) during the embryonic development period. The FO group showed higher body weight gain and feed intake at the finisher stage than the SO group. Body composition analyses by dual-energy X-ray absorptiometry showed that the FO group had higher fat percentage and higher fat mass at day 1, but higher lean mass and total body mass at market age. The decreased expression of key adipogenic genes in the FO group suggested that prenatal FO supplementation in breeder hen diet suppressed adipogenesis in offspring bone marrow. Furthermore, no major differences were observed in expression of osteogenesis marker genes, microstructure change in trabecular bone, or bone mineral density. However, a significant higher close pores/open pores ratio suggested an improvement on bone health of the FO group. Thus, this study indicates that maternal fish oil diet rich in n-3 PUFA could have a favorable impact on fat mass and skeletal integrity in broiler offspring.

Astragalus mongholicus powder, a traditional Chinese medicine formula ameliorate type 2 diabetes by regulating adipoinsular axis in diabetic mice.

The global morbidity of obesity and type 2 diabetes mellitus (T2DM) has dramatically increased. Insulin resistance is the most important pathogenesis and therapeutic target of T2DM. The traditional Chinese medicine formula Astragalus mongholicus powder (APF), consists of Astragalus mongholicus Bunge [Fabaceae], Pueraria montana (Lour.) Merr. [Fabaceae], and Morus alba L. [Moraceae] has a long history to be used to treat diabetes in ancient China. This work aims to investigate the effects of APF on diabetic mice and its underlying mechanism. Diabetic mice were induced by High-fat-diet (HFD) and streptozotocin (STZ). The body weight of mice and their plasma levels of glucose, insulin, leptin and lipids were examined. Reverse transcription-polymerase chain reaction, histology, and Western blot analysis were performed to validate the effects of APF on diabetic mice and investigate the underlying mechanism. APF reduced hyperglycemia, hyperinsulinemia, and hyerleptinemia and attenuate the progression of obesity and non-alcoholic fatty liver disease (NAFLD). However, these effects disappeared in leptin deficient ob/ob diabetic mice and STZ-induced insulin deficient type 1 diabetic mice. Destruction of either these hormones would abolish the therapeutic effects of APF. In addition, APF inhibited the protein expression of PTP1B suppressing insulin–leptin sensitivity, the gluconeogenic gene PEPCK, and the adipogenic gene FAS. Therefore, insulin–leptin sensitivity was normalized, and the gluconeogenic and adipogenic genes were suppressed. In conclusion, APF attenuated obesity, NAFLD, and T2DM by regulating the balance of adipoinsular axis in STZ + HFD induced T2DM mice.

Irisin improves delayed bone repair in diabetic female mice.

Irisin is a proteolytic product of fibronectin type II domain-containing 5, which is related to the improvement in glucose metabolism. Numerous studies have suggested that irisin is a crucial myokine linking muscle to bone in physiological and pathophysiological states. We examined the effects of local irisin administration with gelatin hydrogel sheets and intraperitoneal injection of irisin on the delayed femoral bone repair caused by streptozotocin (STZ)-induced diabetes in female mice. We analyzed the femurs of mice using quantitative computed tomography and histological analyses and then measured the mRNA levels in the damaged mouse tissues. Local irisin administration significantly blunted the delayed bone repair induced by STZ 10days after a femoral bone defect was generated. Local irisin administration significantly blunted the number of Osterix-positive cells that were suppressed by STZ at the damaged site 4days after a femoral bone defect was generated, although it did not affect the mRNA levels of chondrogenic and adipogenic genes 4days after bone injury in the presence or absence of diabetes. On the other hand, intraperitoneal injection of irisin did not affect delayed bone repair induced by STZ 10days after bone injury. Irisin significantly blunted the decrease in Osterix mRNA levels induced by advanced glycation end products or high-glucose conditions in ST2 cells in the presence of bone morphogenetic protein-2. We first showed that local irisin administration with gelatin hydrogel sheets improves the delayed bone repair induced by diabetic state partially by enhancing osteoblastic differentiation.

Thermal stress and selection for growth affect myogenic satellite cell lipid accumulation and adipogenic gene expression through mechanistic target of rapamycin pathway.

Satellite cells (SCs) are multipotential stem cells having the plasticity to convert to an adipogenic lineage in response to thermal stress during the period of peak mitotic activity (the first week after hatch in poultry). The mechanistic target of rapamycin (mTOR) pathway, which regulates cellular function and fate of SCs, is greatly altered by thermal stress in turkey pectoralis major muscle SCs. The objective of the present study was to determine the effects of thermal stress, selection for growth, and the role of the mTOR pathway on SC intracellular lipid accumulation and expression of adipogenic regulatory genes. These effects were analyzed using SCs isolated from the pectoralis major muscle of 1-wk-old modern faster-growing commercial turkey line (NC) selected for increased growth and breast muscle yield as compared with SCs of a historic slower-growing Randombred Control Line 2 (RBC2) turkey. Heat stress (43 °C) of SCs during proliferation increased intracellular lipid accumulation (P < 0.001), whereas cold stress (33 °C) showed an inhibitory effect (P < 0.001) in both lines. Knockdown of mTOR reduced the intracellular lipid accumulation (P < 0.001) and suppressed the expression of several adipogenic regulatory genes: peroxisome proliferator-activated receptor-γ (PPARγ; P < 0.001), CCAAT/enhancer-binding protein-β (C/EBPβ; P < 0.001), and neuropeptide-Y (NPY; P < 0.001) during both proliferation and differentiation. The NC line SCs showed fewer reductions in lipid accumulation compared with the RBC2 line independent of temperature. Both intracellular lipid accumulation (P < 0.001) and PPARγ expression (P < 0.001) were greater at 72 h of proliferation than at 48 h of differentiation in both the RBC2 and NC lines independent of temperature. Thus, hot and cold thermal stress affected intracellular lipid accumulation in the pectoralis major muscle SCs, in part, through the mTOR pathway in wea growth-dependent manner. Altered intracellular lipid accumulation could eventually affect intramuscular fat deposition, resulting in a long-lasting effect on the structure and protein to fat ratio of the poultry pectoralis major muscle.

Taste 2 Receptor Is Involved in Differentiation of 3T3-L1 Preadipocytes

Expression of taste 2 receptor (T2R) genes, also known as bitter taste receptor genes, has been reported in a variety of tissues. The white adipose tissue of mice has been shown to express Tas2r108, Tas2r126, Tas2r135, Tas2r137, and Tas2r143, but the function of T2Rs in adipocytes remains unclear. Here, we show that fasting and stimulation by bitter compounds both increased Tas2r expression in mouse white adipose tissue, and serum starvation and stimulation by bitter compounds both increased the expression of Tas2r genes in 3T3-L1 adipocytes, suggesting that T2Rs have functional roles in adipocytes. RNA sequencing analysis of 3T3-L1 adipocytes stimulated by epicatechin, the ligand of Tas2r126, suggested that this receptor may play a role in the differentiation of adipocytes. Overexpression of Tas2r126 in 3T3-L1 preadipocytes decreases fat accumulation after induction of differentiation and reduces the expression of adipogenic genes. Together, these results indicate that Tas2r126 may be involved in adipocyte differentiation.

Hoxa5 Inhibits the Proliferation and Induces Adipogenic Differentiation of Subcutaneous Preadipocytes in Goats.

Simple SummaryThe homeobox a5 (Hoxa5) is not only a critical developmental transcription factor, but also plays an important role in the regulation of adipocyte differentiation and lipid metabolism. In our study, we found that Hoxa5 promotes goat subcutaneous preadipocyte adipogenic and inhibits its proliferation. This provides a theoretical basis for the regulation of goat subcutaneous preadipocyte differentiation and proliferation.The homeobox a5 (Hoxa5) plays considerable roles in the differentiation and lipid metabolism of adipocytes. However, the current knowledge about the mechanistic roles and functions of Hoxa5 in goat subcutaneous preadipocyte remains unclear. Therefore, Hoxa5 loss-of-function and gain-of-function was performed to reveal its functions in adipogenesis. For differentiation, overexpression of Hoxa5 notably increased the expression of adipogenic genes (PPARγ, CEBP/α, CEBP/β, AP2, and SREBP1), as well as promoted goat subcutaneous preadipocyte lipid accumulation. Knockdown of Hoxa5 mediated by siRNA technique significantly inhibited its differentiation and suppressed the accumulation of lipid droplets. Regarding proliferation, overexpression of Hoxa5 reduced the number of cells stained with crystal violet, and inhibited mRNA expression of the marker genes including CCNE1, PCNA, CCND1, and CDK2, and also significantly reduced EdU-positive rates. Consistently, knockdown of Hoxa5 demonstrated the opposite tendency. In conclusion, these data demonstrated that Hoxa5 promotes adipogenic differentiation of goat subcutaneous preadipocyte and inhibits its proliferation in vitro.

Overexpression of DGAT2 Stimulates Lipid Droplet Formation and Triacylglycerol Accumulation in Bovine Satellite Cells.

Simple SummaryTriacylglycerols are the major component of intramuscular fat, and the final step in their biosynthesis is catalyzed by DGAT2. Bovine skeletal muscle satellite cells were infected with the overexpression adenovirus Ad-DGAT2 and interfering adenovirus sh-DGAT2. The results showed that overexpression of DGAT2 upregulated the expression of genes involved in lipid accumulation and adipogenesis and increased cellular triacylglycerol content. The differentially expressed genes were mainly enriched in the PPAR signaling, glycerolipid metabolism, fatty acid biosynthesis, and AMPK signaling pathways. These results highlight the important regulatory role of DGAT2 during adipogenic transdifferentiation of BSCs and the complexity of intramuscular adipogenesis, as well as providing a theoretical basis for producing high marbling content beef.Intramuscular fat (IMF) is closely related to the tenderness, juiciness, and flavor of beef, and is an important indicator for beef quality assessment internationally. The main components of skeletal intramuscular fat (IMF) are phospholipids and triacylglycerols (TAG), and the final step of TAG biosynthesis is catalyzed by diacylglycerol acyltransferase 2 (DGAT2). To explore the effect of DGAT2 on the differentiation of bovine muscle satellite cells (BSCs) and its role in the signaling pathway related to lipid metabolism, the adenovirus overexpression and interference vector of the DGAT2 gene was constructed in this study, and the overexpression adenovirus Ad-DGAT2 and interfering adenovirus sh-DGAT2 were used to infect BSCs. Overexpression of DGAT2 resulted in a significant increase in the contents of TAG and ADP, and the mRNA and protein expression levels of PPARγ, C/EBPα, and SREBF1 (p < 0.05). Interfering with the expression of DGAT2 reduced the intracellular TAG content and lipid droplet accumulation. Furthermore, the mRNA and protein expression levels of PPARγ, C/EBPα, and SREBF1 (p < 0.05) were significantly downregulated. Transcriptome sequencing showed that a total of 598 differentially expressed genes (DEGs) were screened in BSCs infected with Ad-DGAT2, and these DEGs included 292 upregulated genes and 306 downregulated genes. A total of 49 DEGs were screened in BSCs infected with sh-DGAT2, and these DEGs included 25 upregulated and 24 downregulated genes. KEGG enrichment analysis showed that the DEGs, after overexpression of DGAT2, were mainly enriched in the PPAR signaling pathway, and the fat digestion and absorption, glycerophospholipid metabolism, fatty acid biosynthesis, and AMPK signaling pathways. The DEGs obtained after interfering with DGAT2 were mainly enriched in the metabolic pathways, such as the PPAR signaling pathway and PI3K/AKT signaling pathway. In summary, our study demonstrated that the lipid droplet formation, TAG accumulation, and adipogenic gene expression in BSCs overexpressing DGAT2 were higher than those in the control cells. These results highlight the important role of DGAT2 in regulating BSCs during adipogenic transdifferentiation and underscore the complexity of intramuscular adipogenesis.

Weighted Gene Co-expression Network Analysis Revealed That CircMARK3 Is a Potential CircRNA Affects Fat Deposition in Buffalo.

BackgroundBuffalo meat is increasingly widely accepted for consumption as it shares several quality attributes with cattle meat (beef). Hence, there is a huge opportunity for growth in the buffalo meat industry. However, buffalo meat has relatively low intramuscular fat (IMF) content, affecting its flavor, tenderness and juiciness. As there is a dearth of information on factors that control fat deposition, this study was undertaken to provide new candidate factor associated with buffalo fat deposition. Circular RNA (circRNA) is a novel class of non-coding RNA with a closed-loop structure, and play an important role in fat deposition.MethodsIn this study, weighted gene co-expression network analysis (WGCNA) was used to construct a circRNA co-expression network and revealed a candidate circRNA that may affect the IMF deposition of buffalo as determined by RT-qPCR, semiquantitative PCR and gain-of-function experiments.ResultsHerein, WGCNA determined that one module (turquoise module) is significantly associated with the growth and development stages of buffalo. Further analysis revealed a total of 191 overlapping circRNAs among differentially expressed (DE) circRNAs and the co-expression module. A candidate circRNA was found, 21:6969877|69753491 (circRNA_ID), with a reported involvement in lipid metabolism. This circRNA is stably expressed and originates from the MARK3 gene, hence the name circMARK3. circMARK3 is highly expressed in adipose tissue and mature adipocytes and is located in the cytoplasm. Gain-of-function experiments demonstrated that circMARK3 promoted adipogenic differentiation of buffalo adipocytes and 3T3-L1 cells by up-regulating the expression levels of adipogenic marker genes PPARG, C/EBPα and FABP4.ConclusionThese results indicate that circMARK3 is a potential factor that promotes fat deposition by regulating adipocyte differentiation and adipogenesis in buffalo.

Modulating effects of steviol and steviol glycosides on adipogenesis, lipogenesis, glucose uptake and insulin resistance in 3T3-L1 adipocyte model

• Stevia-derived compounds modulate adipogenic and lipogenic gene expression. • Steviol decreases lipid accumulation in mature 3T3-L1 adipocytes. • Steviol and stevioside improve glucose uptake and mitigate insulin resistance. Stevia rebaudiana Bertoni is famous for sweetness due to the content of steviol glycosides (SG). This study aimed to determine the effect of SG (stevioside, rebaudioside A) and steviol on adipogenesis and lipogenesis in the 3T3-L1 model. Test compounds were also analysed for their ability to affect glucose uptake in hypertrophied insulin-resistant 3T3-L1 adipocytes. The most active compound in modulating adipogenesis, lipogenesis and insulin resistance was steviol, SG metabolism product. Steviol (10 μM, 100 μM) significantly down-regulated the expression of adipogenic transcription factors (PPARγ, C/EBPα, SREBP1) and lipogenic genes (FAS, aP2, LPL), which caused decreased lipid accumulation and triglyceride content in adipocytes. Treatment of insulin-resistant adipocytes with steviol (1 μM) and stevioside (1 μM, 10 μM) increased GLUT-4 transcript level and improved glucose uptake. Steviol also lowered resistin gene expression, which may mitigate insulin resistance in hypertrophied adipocytes. This study promotes SG as potential health-promoting ingredients in low-calorie functional foods.

Targeted erasure of DNA methylation by TET3 drives adipogenic reprogramming and differentiation.

DNA methylation is a crucial epigenetic modification in the establishment of cell-type-specific characteristics. However, how DNA methylation is selectively reprogrammed at adipocyte-specific loci during adipogenesis remains unclear. Here, we show that the transcription factor, C/EBPδ, and the DNA methylation eraser, TET3, cooperatively control adipocyte differentiation. We perform whole-genome bisulfite sequencing to explore the dynamics and regulatory mechanisms of DNA methylation in adipocyte differentiation. During adipogenesis, DNA methylation selectively decreases at adipocyte-specific loci carrying the C/EBP binding motif, which correlates with the activity of adipogenic promoters and enhancers. Mechanistically, we find that C/EBPδ recruits a DNA methylation eraser, TET3, to catalyse DNA demethylation at the C/EBP binding motif and stimulate the expression of key adipogenic genes. Ectopic expression of TET3 potentiates in vitro and in vivo adipocyte differentiation and recovers downregulated adipogenic potential, which is observed in aged mice and humans. Taken together, our study highlights how targeted reprogramming of DNA methylation through cooperative action of the transcription factor C/EBPδ, and the DNA methylation eraser TET3, controls adipocyte differentiation.

Evaluation of human adipose-derived stromal cell behaviour following exposure to Tamoxifen

Background and aimAdipose-derived stromal cells (ASCs) are a promising cell source for novel tissue engineering approaches to breast reconstruction following cancer resection. However there is limited knowledge on the effect of adjuvant therapies such as hormonal therapy on ASCs, which may affect their efficacy in regenerative strategies. The present study aims to investigate the effects of Tamoxifen and its metabolites Afimoxifene (4-Hydroxy-Tamoxifen) and Endoxifen (N-desmethyl-4-hydroxytamoxifen) on patient-derived ASC viability, apoptosis, adipogenic differentiation and angiogenic potential. MethodsASCs were isolated from fat harvested from female breast cancer patients undergoing breast reconstruction surgery or cosmetic procedures. Oestrogen receptor (ER α, β) expression was analysed using immunofluorescence. ASCs were then treated with various concentrations of Afimoxifene, Endoxifen and Tamoxifen (combination), and the impact on ASC viability and apoptosis determined. ASCs were cultured in adipogenic-differentiation media with or without tamoxifen and derivatives, and adipogenesis was measured using quantitative Real-time Polymerase chain reaction (qRT-PCR) and histological staining (Oil Red O). The effect on secreted VEGF levels was also quantified in ASC conditioned media ResultsASCs were successfully isolated and characterised from human abdominal lipoaspirates or fat tissues (n = 8). ASCs subjected to varying doses of Tamoxifen and metabolites (up to 1000 nM) showed no decline in cell viability or increase in apoptosis, at physiological doses (upto 100 nM). Functional decline in adipogenic differentiation or gene expression was observed at supraphysiological concentrations of Tamoxifen (1000 nM). VEGF165 protein secretion in ASC-cell conditioned media was not significantly impacted irrespective of dosage. ConclusionAt physiologically relevant doses, Tamoxifen treatment did not result in any deleterious effect on ASC survival and functionality and is unlikely to negatively impact ASC based breast reconstruction strategies for breast cancer patients receiving this adjuvant hormonal therapy.

Red Rice Bran Extract Attenuates Adipogenesis and Inflammation on White Adipose Tissues in High-Fat Diet-Induced Obese Mice.

Red rice bran extract (RRBE) has been reported to have the potential for in vitro metabolic modulation and anti-inflammatory properties. However, little is known about the molecular mechanisms of these potentials in adipose tissue. This study aimed to evaluate the in vivo anti-adipogenic, anti-hypertrophic, and anti-inflammatory activities of RRBE and its major bioactive compounds in mice. After six weeks of consuming either a low-fat diet or a high-fat diet (HFD), 32 mice with initial body weights of 20.76 ± 0.24 g were randomly divided into four groups; the four groups were fed a low-fat diet, a HFD, a HFD plus 0.5 g/kg of RRBE, or a HFD plus 1 g/kg of RRBE, respectively. The 6-week treatment using RRBE reduced HFD-induced adipocyte hypertrophy, lipid accumulation, and inflammation in intra-abdominal epididymal white adipose tissue (p < 0.05) without causing significant changes in body and adipose tissue weight, which reductions were accompanied by the down-regulated expression of adipogenic and lipid metabolism genes, including CCAAT/enhancer-binding protein-alpha, sterol regulatory element-binding protein-1c, and hormone-sensitive lipase (p < 0.05), as well as inflammatory genes, including macrophage marker F4/80, nuclear factor-kappa B p65, monocyte chemoattractant protein-1, tumor necrosis factor-alpha, and inducible nitric oxide synthase (p < 0.05), in adipose tissue. Furthermore, RRBE significantly decreased serum tumor necrosis factor-alpha levels (p < 0.05). Bioactive compound analyses revealed the presence of phenolics, flavonoids, anthocyanins, and proanthocyanidins in these extracts. Collectively, this study demonstrates that RRBE effectively attenuates HFD-induced pathological adipose tissue remodeling by suppressing adipogenesis, lipid dysmetabolism, and inflammation. Therefore, RRBE may emerge as one of the alternative food products to be used against obesity-associated adipose tissue dysfunction.

Paraspinal Muscle Health is Related to Fibrogenic, Adipogenic, and Myogenic Gene Expression in Patients with Lumbar Spine Pathology

BackgroundLumbar spine pathology is a common feature of lower back and/or lower extremity pain and is associated with observable degenerative changes in the lumbar paraspinal muscles that are associated with poor clinical prognosis. Despite the commonly observed phenotype of muscle degeneration in this patient population, its underlying molecular mechanisms are not well understood. The aim of this study was to investigate the relationships between groups of genes within the atrophic, myogenic, fibrogenic, adipogenic, and inflammatory pathways and multifidus muscle health in individuals undergoing surgery for lumbar spine pathology.MethodsMultifidus muscle biopsies were obtained from patients (n = 59) undergoing surgery for lumbar spine pathology to analyze 42 genes from relevant adipogenic/metabolic, atrophic, fibrogenic, inflammatory, and myogenic gene pathways using quantitative polymerase chain reaction. Multifidus muscle morphology was examined preoperatively in these patients at the level and side of biopsy using T2-weighted magnetic resonance imaging to determine whole muscle compartment area, lean muscle area, fat cross-sectional areas, and proportion of fat within the muscle compartment. These measures were used to investigate the relationships between gene expression patterns and muscle size and quality.ResultsRelationships between gene expression and imaging revealed significant associations between decreased expression of adipogenic/metabolic gene (PPARD), increased expression of fibrogenic gene (COL3A1), and lower fat fraction on MRI (r = -0.346, p = 0.018, and r = 0.386, p = 0.047 respectively). Decreased expression of myogenic gene (mTOR) was related to greater lean muscle cross-sectional area (r = 0.388, p = 0.045).ConclusionFibrogenic and adipogenic/metabolic genes were related to pre-operative muscle quality, and myogenic genes were related to pre-operative muscle size. These findings provide insight into molecular pathways associated with muscle health in the presence of lumbar spine pathology, establishing a foundation for future research that addresses how these changes impact outcomes in this patient population.

Metformin and vitamin D modulate adipose-derived stem cell differentiation towards the beige phenotype

ABSTRACT Adipose-derived stem cells (ADSCs) represent an ideal stem cell population for regenerative medicine. ADSC adipogenic differentiation is controlled by the activation of a specific transcriptional program, including epigenetic factors and key adipogenic genes. Under certain conditioned media, ADSCs can differentiate into several phenotypes. We previously demonstrated that bioactive molecules could counteract lipid accumulation and regulate adipogenesis, acting on inflammation and vitamin D metabolism. In the present paper, we aimed at evaluating the effect of metformin and vitamin D in targeting ADSC differentiation towards an intermediate phenotype, as beige adipocytes. We exposed ADSCs to different conditioned media and then we evaluated the levels of expression of main markers of adipogenesis, aP2, LPL and ACOT2. We also analysed the gene and protein expression of thermogenic UCP1 protein, and the expression of PARP1 and the beige specific marker TMEM26. Our results showed a novel effect of metformin and vitamin D not only in inhibiting adipogenesis, but also in inducing a specific ‘brown-like’ phenotype. These findings pave the way for their possible application in the control of de novo lipogenesis useful for the prevention of obesity and its related metabolic disorders.