Inhibited Preadipocyte Differentiation Research Articles

Anti-adipogenic effect of heat-treated probiotic Lactiplantibacillus plantarum WB2719 and Lacticaseibacillus rhamnosus WB2804

Lactiplantibacillus plantarum WB2719 and Lacticaseibacillus rhamnosus WB2804 were isolated from fermented foods. These strains were demonstrated probiotic traits and anti-adipogenic effects. These strains exhibited tolerance to artificial gastric conditions and adhesion activities to intestine cells. Furthermore, heat-treated L. plantarum WB2719 and L. rhamnosus WB2804 inhibited preadipocyte differentiation by modulating peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT/enhancer binding proteins α (C/EBP-α), and fatty acid synthase (FAS) expression. In particular, heat-treated L. plantarum WB2719 decreased mitosis and exerted anti-obesity effects by inducing apoptosis. Therefore, this study proposes the potential commercialization of heat-treated L. plantarum WB2719 and L. rhamnosus WB2804 as novel food-derived anti-obesity materials in the expanding health-functional food sector.

Epigallocatechin gallate suppresses mitotic clonal expansion and adipogenic differentiation of preadipocytes through impeding JAK2/STAT3-mediated transcriptional cascades

BackgroundMitotic clonal expansion (MCE) is a prerequisite for preadipocyte differentiation and adipogenesis. Epigallocatechin gallate (EGCG) has been shown to inhibit preadipocyte differentiation. However, the exact molecular mechanisms are still elusive. PurposeThis study investigated whether EGCG could inhibit adipogenesis and lipid accumulation by regulating the cell cycle in the MCE phase of adipogenesis and its underlying molecular mechanisms. Method3T3-L1 preadipocytes were induced to differentiate by a differentiation cocktail (DMI) and were treated with EGCG (25–100 μM) for 9, 18, and 24 h to examine the effect on MCE, or eight days to examine the effect on terminal differentiation. C57BL/6 mice were fed a high-fat diet (HFD) for three months to induce obesity and were given EGCG (50 or 100 mg/kg) daily by gavage. ResultsWe showed that EGCG significantly inhibited terminal adipogenesis and lipid accumulation in 3T3-L1 cells and decreased expressions of PPARγ, C/EBPα, and FASN. Notably, at the MCE phase, EGCG regulated the cell cycle in sequential order, induced G0/G1 arrest at 18 h, and inhibited the G2/M phase at 24 h upon DMI treatment. Meanwhile, EGCG regulated the expressions of cell cycle regulators (cyclin D1, cyclin E1, CDK4, CDK6, cyclin B1, cyclin B2, p16, and p27), and decreased C/EBPβ, PPARγ, and C/EBPα expressions at MCE. Mechanistic studies using STAT3 agonist Colivelin and antagonist C188–9 revealed that EGCG-induced cell cycle arrest in the MCE phase and terminal adipocyte differentiation was mediated by the inhibition of JAK2/STAT3 signaling cascades and STAT3 (Tyr705) nuclear translocation. Furthermore, EGCG significantly protected mice from HFD-induced obesity, reduced body weight and lipid accumulations in adipose tissues, reduced hyperlipidemia and leptin levels, and improved glucose intolerance and insulin sensitivity. Moreover, RNA sequencing (RNA-seq) analysis showed that the cell cycle changes in epididymal white adipose tissue (eWAT) were significantly enriched upon EGCG treatment. We further verified that EGCG treatment significantly reduced expressions of adipogenic factors, cell cycle regulators, and p-STAT3 in eWAT. ConclusionEGCG inhibits MCE, resulting in the inhibition of early and terminal adipocyte differentiation and lipid accumulation, which were mediated by inhibiting p-STAT3 nucleus translocation and activation.

Sexual dimorphism in thermogenic regulators and metrnl expression in adipose tissue of offspring mice exposed to maternal and postnatal overnutrition.

Current study investigated the impact of maternaland postnatal overnutrition on phenotype of adipose, in relation to offspring thermogenesis and sex. Female C57BL/6J mice were fed with CHOW or high fat diet (HFD) for 2weeks before mating, throughout gestation and lactation. At weaning, pups were fed to 9weeks old with CHOW or HFD, which resulted in four groups for each gender--male or female: CHOW-CHOW (CC), CHOW-HFD (CH), HFD-CHOW (HC), HFD-HFD (HH). Maternal and post-weaning HFD enhanced thermogenic factors such as Acox1, Dio2 and Cox8b in iBAT of male and female offspring, but increased SIRT1, PGC-1α and UCP1 only in female. However, Acox1, Dio2 and Cox8b mRNA expression and SIRT1, PGC-1α and UCP1 protein expression were only enhanced upon maternal and post-weaning HFD in sWAT and pWAT of female offspring. Increased metrnl expression in adipose were observed in sex- and depot-specific manner, while enhanced circulating metrnl level was only observed in male offspring undergoing maternal HFD. Palmitic acid changed metrnl expression during preadipocytes differentiation and siRNA-mediated knockdown of metrnl inhibited preadipocyte differentiation. Female offspring were more prone to resist adverse outcomes induced by maternal and post-weaning overnutrition, which probably related to metrnl expression and thermogenesis.

Insights into the Surface Binding and Structural Interference of Polyphenols with the Membrane Raft Domains in Relation to Their Distinctive Ability to Inhibit Preadipocyte Differentiation in 3T3-L1 Cells.

Polyphenols with different structures have shown distinct variations in their ability to inhibit the differentiation of 3T3-L1 preadipocytes. However, the underlying mechanisms for these differences remain unclear. In the present study, the surface binding of polyphenols to different membrane domains was explored using coarse-grained molecular dynamics simulation (CG-MDs). Subsequently, this surface binding was confirmed in the liposome system by microscale thermophoresis. Additionally, the interference of polyphenols on the membrane raft's structure was studied through atomic force microscopy and high-content screening fluorescence microscopy. The results indicated that polyphenols with a differentiation-inhibitory ability, such as epicatechin-3-gallate (ECG) and epicatechin-3-gallate-(4β → 8, 2β → O → 7)-epicatechin-3-gallate (A-type ECG dimer), exhibited strong binding to ordered domains enriched in sphingolipids and cholesterol. This binding led to the structural disruption of membrane rafts by altering their size and shape, with the binding constant of 3.8 μM for ECG and 0.3 μM for A-type ECG dimer, respectively. In contrast, epicatechin (EC) with little differentiation-inhibitory ability had no effects on membrane rafts, and its binding constant with the ordered domain was 380.6 μM. Overall, the surface binding of polyphenols to ordered domains and the resulting disruption of membrane rafts structure might be a fundamental mechanism by which polyphenols inhibited the differentiation of 3T3-L1 preadipocytes.

SAT652 The Expression Of The Immunoproteasome Subunit Psmb9 Is Related To Obesity And The Differentiation Of Human Preadipocytes

Abstract Disclosure: Y. Cui: None. X. Zhang: None. L. You: None. H. Zhong: None. X. Cui: None. C. Ji: None. Obesity and its associated chronic diseases, such as type 2 diabetes mellitus, hypertension, and coronary artery disease, afflicting adults and children globally. PSMB9, a proteolytic subunit of the immunoproteasome that shapes the repertoire of antigenic peptides, is hypothesized to be associated with obesity. To investigate this association, we examined PSMB9 expression in primary mature adipocytes from obese and normal individuals. LC-MS/MS-PRM was used to quantify PSMB9 content in primary mature adipocytes, revealing a negative correlation between PSMB9 content and obesity while positively correlated with high-density lipoprotein levels. Furthermore, we examined the effect of PSMB9 on human preadipocyte differentiation. During the early stages of differentiation, the expression of PSMB9 was at its highest level, decreasing as preadipocytes matured. Overexpression of PSMB9 significantly inhibited preadipocyte differentiation, resulting in reduced lipid droplets and decreased expression levels of classical differentiation markers such as FABP4, C/EBPα, and PPARγ. These findings suggest that PSMB9 could be a potential therapeutic target for preventing and treating obesity and metabolic disorders. In conclusion, our study provides insights into the role of the immunoproteasome in obesity and highlights the importance of further exploration of this pathway. Presentation: Saturday, June 17, 2023

Balancing adipocyte production and lipid metabolism to treat obesity-induced diabetes with a novel proteoglycan from Ganoderma lucidum

Obesity is often accompanied by metabolic disorder and insulin resistance, resulting in type 2 diabetes. Based on previous findings, FYGL, a natural hyperbranched proteoglycan extracted from the G. lucidum fruiting body, can decrease blood glucose and reduce body weight in diabetic mice. In this article, the underlying mechanism of FYGL in ameliorating obesity-induced diabetes was further investigated both in vivo and in vitro. FYGL upregulated expression of metabolic genes related to fatty acid biosynthesis, fatty acid β-oxidation and thermogenesis; downregulated the expression of insulin resistance-related genes; and significantly increased the number of beige adipocytes in db/db mice. In addition, FYGL inhibited preadipocyte differentiation of 3T3-L1 cells by increasing the expression of FABP-4. FYGL not only promoted fatty acid synthesis but also more significantly promoted triglyceride degradation and metabolism by activating the AMPK signalling pathway, therefore preventing fat accumulation, balancing adipocyte production and lipid metabolism, and regulating metabolic disorders and unhealthy obesity. FYGL could be used as a promising pharmacological agent for the treatment of metabolic disorder-related obesity.

Long noncoding RNA ACART knockdown decreases 3T3-L1 preadipocyte proliferation and differentiation.

Obesity is a main risk factor for diabetes and cardiovascular disorders and is closely linked to preadipocyte differentiation or adipogenesis. Peroxisome proliferator-activated receptor γ (PPARγ) is an indispensable transcription factor in adipogenesis. A newly identified long noncoding RNA, Acart, exerts a protective effect against cardiomyocyte injury by transactivating PPARγ signaling. However, the function of Acart in preadipocyte differentiation is unclear. To investigate the function of Acart in adipogenesis, a well-established preadipocyte, the 3T3-L1 cell line, was induced to differentiate, and Acart level was assessed during differentiation using quantitative real-time PCR. The biological role of Acart in adipogenesis was analyzed by assessing lipid droplet accumulation, PPARγ and CCAAT/enhancer-binding protein α (C/EBPα) expression, and 3T3-L1 cell proliferation and apoptosis after Acart silencing. We found that Acart level was promptly increased during preadipocyte differentiation in vitro. Acart was also significantly upregulated in obese mouse-derived subcutaneous, perirenal, and epididymal fat tissues compared with nonobese mouse-derived adipose tissues. Functionally, Acart depletion inhibited preadipocyte differentiation, as evidenced by a significant decrease in lipid accumulation and PPARγ and C/EBPα expression levels. Acart silencing also inhibited 3T3-L1 cell proliferation, whereas Acart overexpression accelerated 3T3-L1 cell proliferation and decreased cell apoptosis. Taken together, the current results reveal a novel function of Acart in regulating preadipocyte proliferation and differentiation.

Effects of caffeoylquinic acid analogs derived from aerial parts of Artemisia iwayomogi on adipogenesis.

Artemisia iwayomogi (AI) is a perennial herb found in Korea. Its ground parts are dried and used in food and traditional medicine for treating hepatitis, inflammation, cholelithiasis, and jaundice. In this study, the anti-obesity effects of single compounds isolated from AI extracts on adipose tissue were investigated. Results demonstrated that caffeoylquinic acid analogs strongly inhibited adipocyte differentiation from 3T3-L1 preadipocytes and reduced neutral lipids in differentiated adipocytes. Accordingly, lipid accumulation in adipocytes decreased, and lipid droplets became granulated. Caffeoylquinic acid analogs suppressed the expression of adipocyte differentiation marker genes, namely, Cebpa, Lep, and Fabp4, but it induced the expression of Ucp1, Ppargc1a, and Fgf21, which are browning biomarkers. Therefore, caffeoylquinic acid analogs from AI inhibited preadipocyte differentiation and induced adipose tissue browning, suggesting that these compounds could be promising therapeutic agents for obesity.

MiR-503 targets MafK to inhibit subcutaneous preadipocyte adipogenesis causing a decrease of backfat thickness in Guanzhong Black pigs

Reducing backfat thickness (BFT), determined by subcutaneous fat deposition, is vital in Chinese developed pig breeds. The level of miR-503 in the backfat of Guanzhong Black pigs was found to be lower than that in Large White pigs, implying that miR-503 may be related to BFT. However, the effect and mechanism of miR-503 on adipogenic differentiation in subcutaneous preadipocytes remain unknown. Compared with Large White pigs, the BFT and body fat content of Guanzhong Black pigs were greater, but the level of miR-503 was lower in subcutaneous adipose tissue (SAT) at 180 days of age. Furthermore, miR-503 promoted preadipocyte proliferation by increasing the proportion of S-phase and EdU-positive cells. However, miR-503 inhibited preadipocyte differentiation by downregulating adipogenic gene expression. Mechanistically, miR-503 directly targeted musculoaponeurotic fibrosarcoma oncogene homolog K (MafK) in both proliferating and differentiating preadipocytes to repress adipogenesis. Our findings provide a novel miRNA biomarker for reducing pig BFT levels to improve carcass quality.

Anti-obesity effects of corn peptide on 3T3-L1 preadipocytes and C57BL/6J obese mice

ABSTRACT Corn peptide (CP) is a small, natural, biologically active peptide obtained by protease-catalysed hydrolysis of corn. CP exerts antihypertensive, hypoglycaemic, antihyperlipidemic, antioxidant, and antitumor effects, as well as prevents cardiovascular and cerebrovascular diseases. Although CP plays a role in preventing obesity-related diseases, its role in reducing obesity has not yet been determined. In this study, we analysed the inhibitory effects of CP on lipid droplet accumulation in 3T3-L1 preadipocytes and high-fat diet (HFD)-induced C57BL/6J Obese Mice. The results show that CP could inhibit preadipocyte differentiation and oil accumulation in 3T3-L1 preadipocytes. Oral CP administration reduced serum triglyceride (TG) content, epididymal fat weight, abnormal liver fat droplet accumulation, and C/EBPα expression. Furthermore, combination of CP administration and exercise reduced body, liver, and adipose tissue weights; decreased serum total cholesterol (TC), triglyceride and low-density lipoprotein (LDL) levels; and inhibited hepatic lipid droplet accumulations and epididymal fat cell hypertrophy. Additionally, this combination inhibited the expression of transcription factors, C/EBPα, C/EBPβ, and PPARγ, and adipogenic factors, FABP4 in mice. In conclusion, oral administration of CP inhibited lipid droplet accumulation and counteracted HFD-induced obesity in mice.

Tamarind Seed Coat: A Catechin-Rich Source with Anti-Oxidation, Anti-Melanogenesis, Anti-Adipogenesis and Anti-Microbial Activities.

Tamarindus indica L. or tamarind seed is an industrial by-product of interest to be investigated for its potential and value-added application. An ethanolic tamarind seed coat (TS) extract was prepared using the maceration technique and used to determine the phytochemical composition and bioactivities. The total phenolic and flavonoid contents were determined using colorimetric methods; moreover, chemical constituents were identified and quantified compared to the standard compounds using the HPLC-UV DAD technique. Bioactivities were investigated using various models: antioxidative activity in a DPPH assay model, anti-melanogenesis in B16 melanoma cells, anti-adipogenesis in 3T3-L1 adipocytes, and anti-microbial activity against S. aureus, P. aeruginosa, E. coli, and C. albican using agar disc diffusion and microdilution methods. The results manifested a high content of catechin as a chemical constituent and multiple beneficiary bioactivities of TS extract, including superior antioxidation to ascorbic acid and catechin, comparable anti-melanogenesis to deoxyarbutin, and significant anti-adipogenesis through inhibition of pre-adipocyte differentiation and reduction of lipid and triglyceride accumulation, and a broad spectral anti-microbial activity with a selectively high susceptibility to S. aureus when compared to 1% Parabens. Conclusively, TS extract has been revealed as a potential bioactive agent as well as an alternative preservative for application in food, cosmetic, and pharmaceutical product development.

Polysaccharide CM1 from Cordyceps militaris hinders adipocyte differentiation and alleviates hyperlipidemia in LDLR(+/\u2212) hamsters

BackgroundCordyceps militaris is cultured widely as an edible mushroom and accumulating evidence in mice have demonstrated that the polysaccharides of Cordyceps species have lipid-lowering effects. However, lipid metabolism in mice is significantly different from that in humans, making a full understanding of the mechanisms at play critical.MethodsAfter 5 months, the hamsters were weighed and sampled under anesthesia after overnight fasting. The lipid-lowering effect and mechanisms of the polysaccharide CM1 was investigated by cellular and molecular technologies. Furthermore, the effect of the polysaccharide CM1 (100 μg/mL) on inhibiting adipocyte differentiation was investigated in vitro.ResultsCM1, a polysaccharide from C. militaris, significantly decreased plasma total cholesterol, triglyceride and epididymal fat index in LDLR(+/−) hamsters, which have a human-like lipid profile. After 5 months’ administration, CM1 decreased the plasma level of apolipoprotein B48, modulated the expression of key genes and proteins in liver, small intestine, and epididymal fat. CM1 also inhibited preadipocyte differentiation in 3T3-L1 cells by downregulating the key genes involved in lipid droplet formation.ConclusionsThe polysaccharide CM1 lowers lipid and adipocyte differentiation by several pathways, and it has potential applications for hyperlipidemia prevention.

Long Non-coding RNA 332443 Inhibits Preadipocyte Differentiation by Targeting Runx1 and p38-MAPK and ERK1/2-MAPK Signaling Pathways

Long non-coding RNAs (lncRNAs) have emerged as integral regulators of pathophysiological processes, but their specific roles and mechanisms in adipose tissue development remain largely unknown. Here, through microarray analysis, co-expression, and tissue specific analysis of adipocyte tissues after fasting for 72 h, we found that Lnc-FR332443 expression was dramatically decreased, as well as the expression of Runx1. The UCSC database and Ensembl database indicated that Lnc-FR332443 is the antisense lncRNA of Runx1. Lnc-FR332443 and Runx1 are highly enriched in adipose tissue and downregulated during adipogenic differentiation. Adipose tissue-specific knockdown of Lnc-FR332443 increased fat mass in vivo, and specific knockdown of Lnc-FR332443 in 3T3-L1 preadipocytes promoted adipogenic differentiation. In this process, Runx1 expression was decreased when Lnc-FR332443 was downregulated in adipocytes or 3T3-L1 preadipocytes, and vice versa, when Lnc-FR332443 was upregulated, the expression of Runx1 was increased. However, overexpression of Runx1 decreased the expression of the adipocyte cell marker genes PPARγ, C/EBPα and FABP4 significantly, while not affected the expression of Lnc-FR332443. Mechanistically, Lnc-FR332443 positively regulates Runx1 expression in mouse adipocytes and suppresses adipocyte differentiation by attenuating the phosphorylation of MAPK-p38 and MAPK-ERK1/2 expression. Thus, this study indicated that Lnc-FR332443 inhibits adipogenesis and which might be a drug target for the prevention and treatment of obesity.

Inhibition of preadipocyte differentiation by Lycium barbarum polysaccharide treatment in 3T3-L1 cultures

Background: Lycium barbarum (also called wolfberry), a famous Chinese traditional medicine and food ingredient, is well recognized for its significant role in preventing obesity; however, the molecular mechanisms underlying its preventive effects on fat accumulation are not well understood yet. The aim of this study was to determine the effects and mechanism of Lycium barbarum polysaccharides (LBP) on the proliferation and differentiation of 3T3-L1 preadipocytes. MTT was used to detect the proliferation of 3T3-Ll preadipocytes. Oil red O staining and colorimetric analysis were used to detect cytosolic lipid accumulation during 3T3-L1 preadipocyte differentiation. Real-time fluorescent quantitative PCR (qPCR) technology was used to detect peroxisome proliferator-activated receptor γ ( PPARγ ), CCAAT/enhancer-binding protein α ( C/EBPα ), adipocyte fatty-acid-binding protein ( aP2 ), fatty acid synthase ( FAS ), and lipoprotein lipase ( LPL ) expression. Results: The concentration of LBP from 25 to 200 μg/mL showed a tendency to inhibit the growth of preadipocytes at 24 h, and it inhibited the differentiation of 3T3-L1 preadipocytes in a dose-dependent manner. In the preadipocytes treated with 200 μg/mL LBP, there were reduced lipid droplets in the cytoplasm, and its effect was opposite to that of rosiglitazone (ROS), which significantly reduced the PPARγ , C/EBPα , aP2 , FAS , and LPL mRNA expression of adipocytes. Conclusions: LBP exerts inhibitive effects on the proliferation and differentiation of 3T3-L1 preadipocytes and decreases the cytoplasm accumulation of lipid droplets during induced differentiation of preadipocytes toward mature cells. Above phenomenon might link to lowered expression of PPARγ , C/EBPα , aP2 , FAS , and LPL after LBP treatment. Thus, LBP could serve as a potential plant extract to treat human obesity or improve farm animal carcass quality via adjusting lipid metabolism. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Tabla normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:8.0pt; mso-para-margin-left:0cm; line-height:107%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri,sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Times New Roman; mso-bidi-theme-font:minor-bidi;}

Pomegranate flower extract bidirectionally regulates the proliferation, differentiation and apoptosis of 3T3-L1 cells through regulation of PPARγ expression mediated by PI3K-AKT signaling pathway

ObjectivesPomegranate flower is a kind of uygur medicine with anti - type 2 diabetes, anti - lipid, anti - inflammation, anti - oxidation. We investigated the effect of pomegranate flower extract (PFE) on the proliferation, differentiation and apoptosis of 3T3-L1 preadipocytes, as well as the effects of five compounds in PF on cell differentiation. Methods3T3-L1 preadipocytes were treated with PFE (0.5, 1, 2, 5, 10, 20, 50, 100 μg/mL), quercetin, luteolin, ursolic acid, apigenin and kaempferol (5, 10, 20, 40, 80 μM), and cell viability was measured at 24, 48 and 72 h by Cell Counting Kit-8. The modified cocktail induction method induced the differentiation of 3T3-L1 preadipocytes, and treated them with PFE and the compounds. The lipid accumulation was determined by oil red O staining, and the intracellular triglyceride content was determined by commercial kit. The expressions of PPARγ, C/EBP, LPL, DGAT and aP2 mRNA in mature adipocyte were determined by q-PCR, and the expressions of PPARγ, Akt, p-akt and PI3K protein were determined by western blot. 3T3-L1 preadipocytes were treated with PFE (5, 10, 20 μg/mL) while induced apoptosis by palmitate (300 μM), Hoechst staining to observe apoptosis morphology, Annexin Ⅴ- FITC/PI staining with flow cytometry instrument to detect the number of early and late apoptosis cells, the q-PCR and western blot for determining the Bcl-2, Bax, caspase 3 mRNA and protein expression. ResultsPFE (5, 10, 20 μg/mL) promoted or did not affect the proliferation and differentiation of 3T3-L1 preadipocytes, and reduced the number of early and late apoptotic cells, increased the expression of Bcl-2 mRNA and protein, and inhibited the expression of Bax and caspase-3 mRNA and protein. Furthermore, PFE (40, 60 μg/mL), quercetin (10, 20, 40 μM), luteolin (5, 10, 20 μM), apigenin(20,40 μM), kaempferol (20, 40 μM) significantly restrain the 3T3-L1 different extent proliferation and differentiation of preadipocyte, reduce the accumulation of lipids in adipocyte, reduce expression of adipogenesis factor, PFE(40, 60 μg/mL) inhibited the activation of the PI3K-Akt pathway by inhibiting the expression of PI3K and p-Akt proteins, and inhibited preadipocyte differentiation by reduce the expression of PPARγ protein. ConclusionPFE has a concentration-related bidirectional effect on the proliferation, differentiation and apoptosis of 3T3-L1 preadipocytes, which depends on the regulation of PI3K-Akt pathway, which is of guiding role for PFE in the treatment of type 2 diabetes, hyperlipidemia, obesity and other diseases.

SIRT6 cooperates with SIRT5 to regulate bovine preadipocyte differentiation and lipid metabolism via the AMPKα signaling pathway

Preadipocyte differentiation and lipid synthesis are critical steps for intramuscular fat (IMF) deposition and lipid metabolism homeostasis. IMF content of beef not only determines the ratio of muscle to adipose, but also determines the beef quality, flavor, and sensory characteristics. Maintaining lipid metabolism homeostasis is the key means of preventing and treating diabetes, obesity, and other metabolic diseases. SIRT6, which is an ADP-ribosyltransferase and NAD+-dependent deacetylase of acetyl and long-chain fatty acyl groups, playing central roles in lipid and glucose metabolism, is closely related to the occurrence of diabetes and obesity caused by overnutrition and aging. This study was based on bovine preadipocyte differentiation and an obese mice model, and comprehensively used transcriptome sequencing (RNA-seq) and morphological identification methods to explore the effects of inhibition of SIRT6 on differentiation and lipid synthesis, and related molecular mechanisms. Additionally, the feedback synergistic regulation of SIRT5 and SIRT6 on differentiation and lipid deposition was analyzed. The results showed that in the differentiation process of bovine preadipocytes, inhibition of SIRT5 significantly promoted SIRT6 expression. In addition, SIRT6 inhibited bovine preadipocyte differentiation and lipid synthesis, cooperating with SIRT5 to decrease lipid deposition, and repressed cell cycle arrest of preadipocytes. Moreover, in vivo verification experiments also obtained consistent results. Furthermore, SIRT6 inhibited preadipocyte differentiation and lipid deposition by activating the adenosine monophosphate activated protein kinase alpha (AMPKα) pathway. The above results provided a novel approach for understanding the functions of SIRT6 in regulating bovine adipocyte differentiation and lipid metabolism, as well as a new target for the treatment of diabetes and obesity in a clinical setting.

Neudesin Neurotrophic Factor Promotes Bovine Preadipocyte Differentiation and Inhibits Myoblast Myogenesis.

Simple SummaryNeudesin neurotrophic factor (NENF) is a secreted protein that was significantly inhibited in the fat-muscle co-culture system in our previous study. However, studies on NENF regulation of bovine muscle development and involvement in the cross-talk between adipose tissue and skeletal muscle have not been reported. Hence, the aim of this study was to clarify the roles of NENF in bovine myoblast and preadipocyte differentiation. In this study, we first examined the spatial expression patterns of NENF in different tissues and found that NENF was highly expressed in the muscle of four-day-old and 24-month-old Qinchuan cattle. Compared with 4-day-old Qinchuan cattle, the expression level of NENF was significantly up-regulated in 24-month-old bovine adipose tissue. Then, we detected the expression pattern of the NENF gene in bovine preadipocyte and myoblast differentiation and found that the expression of NENF mRNA peaks at day 6 during preadipocyte differentiation and peaks at day 4 during myoblast differentiation. Furthermore, we found that the endogenous knockdown of NENF inhibited the differentiation of preadipocytes and promoted the differentiation of myoblasts. These findings not only lay the foundation for the construction of regulatory pathways during fat and muscle differentiation but also provide a theoretical basis for molecular breeding of beef cattle.Neudesin neurotrophic factor (NENF) is a secreted protein that is essential in multiple biological processes, including neural functions, adipogenesis, and tumorigenesis. In our previous study, NENF was significantly inhibited in the bovine adipocytes-myoblasts co-culture system. However, studies on NENF regulation of bovine muscle development and involvement in the cross-talk between adipose tissue and skeletal muscle have not been reported. Hence, the aim of this study was to clarify the functional roles of NENF in bovine preadipocytes and myoblasts. Real-time quantitative PCR (RT-qPCR) was performed to examine the spatial expression patterns of NENF in different tissues, and the results showed that NENF was highly expressed in the muscle of four-day-old and 24-month-old Qinchuan cattle. Compared with four-day-old Qinchuan cattle, the expression level of NENF was significantly up-regulated in 24-month-old bovine adipose tissue. To explore the roles of NENF in bovine myoblast and preadipocyte differentiation, small interfering RNA (siRNA) targeting the NENF gene were transfected into bovine preadipocytes and myoblasts to knock down the expression of the NENF gene. The results showed that the knockdown of NENF in differentiating adipocytes attenuated lipid accumulation, decreased the mRNA expression of adipogenic key marker genes PPARγ, CEBPα, CEBPβ, FASN, and SCD1, and decreased the protein expression of PPARγ, CEBPα, and FASN. The formation of myotubes was significantly accelerated, and the mRNA expression levels of myogenic marker genes MYOD1, MYF5, MYF6, MEF2A, MEF2C, and CKM, and the protein expression levels of MYOD1, MYF6, MEF2A, and CKM were up-regulated in myoblasts where NENF was knocked down. In short, the knockdown of NENF inhibited preadipocyte differentiation and promoted myoblast myogenesis.

1\u03b1, 25-dihydroxy Vitamin D3 containing fractions of Catharanthus roseus leaf aqueous extract inhibit preadipocyte differentiation and induce lipolysis in 3T3-L1 cells

BackgroundTo investigate the potential of Catharanthus roseus leaf aqueous crude extract (CRACE) as a regulator of adipocyte development and function.Methods3T3-L1 adipogenesis model was used to investigate the effect of CRACE on adipogenesis. 3T3-L1 preadipocytes (for adipogenic differentiation) and mature 3T3-L1 adipocytes (for adipocyte function) were treated with non-toxic doses of CRACE. The outcomes were corroborated by intracellular lipid accumulation, expression of pro-and anti-adipogenic effector molecules. To investigate CRACE mediated lipolysis, cAMP accumulation, glycerol release and phosphorylation of key effector molecules were tested in treated mature adipocytes. Finally, the extract was fractionated to identify the active molecule/s in the extract.ResultsCRACE significantly reduced adipocyte differentiation by modulating PPARγ expression. At early stage CRACE directly targeted Lipin1 expression and consequently impacted KLF7, subsequently expression of GATA2, CEBPα, SREBP1c were targeted, with PPARγ expression, particularly curtailed. While CRACE significantly reduced several lipogenic genes like FAS and GPD1 in mature adipocytes, concomitantly, it greatly increased lipolysis resulting in decreased lipid accumulation in mature adipocytes. The increase in lipolysis was due to decreased Akt activation, increased cAMP level, and PKA activity. The fractionation of CRACE allowed identification of two fractions with potent anti-adipogenic activity. Both the fractions contained 1α, 25-dihydroxy Vitamin D3 as major component.Conclusions1α, 25-dihydroxy Vitamin D3 containing CRACE can be developed into an effective anti-obesity formulation that decreases adipogenesis and increases lipid catabolism.

Resveratrol Inhibits Human Visceral Preadipocyte Proliferation and Differentiation in vitro.

Visceral obesity is a high-risk factor for diabetes and metabolic syndrome. Resveratrol, a natural polyphenolic compound, has been reported to inhibit preadipocyte differentiation. However, the effect of resveratrol on human visceral preadipocyte (HPA-v) differentiation remains largely unknown. LIM domain only 3 (LMO3) promotes human preadipocyte differentiation by enhancing peroxisome proliferator-activated receptor γ (PPARγ) transcriptional activity, which is the master regulator of adipogenesis. The purpose of our study was to determine the effect of resveratrol (0-50 μM) on HPA-v proliferation and differentiation, and the role of LMO3 in resveratrol-mediated regulation of HPA-v differentiation. Resveratrol inhibited HPA-v proliferation and differentiation in a dose-dependent manner, and significantly decreased the mRNA expression levels of PPARG, CCAAT/enhancer-binding protein α (CEBPA), fatty acid-binding protein 4 (FABP4), acetyl-CoA carboxylase (ACC), and fatty acid synthase (FAS) (p < 0.05) at 10, 20, and 50 μM. The mRNA and protein levels of LMO3 were significantly reduced by ≥20 μM resveratrol (p < 0.05), and overexpression of LMO3 partially attenuated resveratrol-induced reduction of HPA-v differentiation by enhancing the PPARG transcriptional activity. Together, our study suggested that resveratrol reduced HPA-v proliferation and differentiation, as well as LMO3, which was partially responsible for the reduction of resveratrol-mediated adipocyte differentiation.

Dynamics of transcriptome changes during subcutaneous preadipocyte differentiation in ducks

BackgroundPekin duck is an important animal model for its ability for fat synthesis and deposition. However, transcriptional dynamic regulation of adipose differentiation driven by complex signal cascades remains largely unexplored in this model. This study aimed to explore adipogenic transcriptional dynamics before (proliferation) and after (differentiation) initial preadipocyte differentiation in ducks.ResultsExogenous oleic acid alone successfully induced duck subcutaneous preadipocyte differentiation. We explored 36 mRNA-seq libraries in order to study transcriptome dynamics during proliferation and differentiation processes at 6 time points. Using robust statistical analysis, we identified 845, 652, 359, 2401 and 1933 genes differentially expressed between -48 h and 0 h, 0 h and 12 h, 12 h and 24 h, 24 h and 48 h, 48 h and 72 h, respectively (FDR < 0.05, FC > 1.5). At the proliferation stage, proliferation related pathways and basic cellular and metabolic processes were inhibited, while regulatory factors that initiate differentiation enter the ready-to-activate state, which provides a precondition for initiating adipose differentiation. According to weighted gene co-expression network analysis, pathways positively related to adipogenic differentiation are significantly activated at the differentiation stage, while WNT, FOXO and other pathways that inhibit preadipocyte differentiation are negatively regulated. Moreover, we identified and classified more than 100 transcription factors that showed significant changes during differentiation, and found novel transcription factors that were not reported to be related to preadipoctye differentiation. Finally, we manually assembled a proposed regulation network model of subcutaneous preadipocyte differentiation base on the expression data, and suggested that E2F1 may serve as an important link between the processes of duck subcutaneous preadipocyte proliferation and differentiation.ConclusionsFor the first time we comprehensively analyzed the transcriptome dynamics of duck subcutaneous preadipocyte proliferation and differentiation. The current study provides a solid basis for understanding the synthesis and deposition of subcutaneous fat in ducks. Furthermore, the information generated will allow future investigations of specific genes involved in particular stages of duck adipogenesis.