Gga-let-7a-3p inhibits the proliferation and differentiation of chicken intramuscular preadipocytes

1. Intramuscular fat (IMF) is a key parameter for chicken meat quality. IMF deposition is driven by genetic, nutritional and management factors, with genetics being the determining factor. Previous whole transcriptome sequencing revealed that microRNA gga-let-7a-3p was related to lipid metabolism in breast muscle. This study further investigated the potential role of gga-let-7a-3p in IMF deposition.2. The mimic and inhibitor of gga-let-7a-3p were individually transfected into chicken intramuscular preadipocytes. Subsequently, the proliferation and differentiation states of the cells were detected. Transcriptome sequencing was performed on cells transfected with gga-let-7a-3p mimic.3. The results indicated that gga-let-7a-3p suppressed the mRNA levels of proliferation and differentiation-related genes, as well as the protein levels. EdU and Oil Red O assays revealed that gga-let-7a-3p restrained preadipocyte proliferation and differentiation. In addition, a total of 333 up-regulated genes and 807 down-regulated genes were identified in cells transfected with gga-let-7a-3p mimic. Using Kyoto Encyclopaedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analysis, differential genes were found to be enriched in processes such as the peroxisome proliferator activated receptor (PPAR) signalling pathway and oxidative phosphorylation.4. The study demonstrated that gga-let-7a-3p inhibits the proliferation and differentiation of chicken intramuscular preadipocytes, which provides new understanding to further unravel the function of gga-let-7a-3p.

Let-7a-5p Regulates Animal Lipid Accumulation by Targeting Srebf2 and Thbs1 Signaling

Recently, the trend of obesity is becoming increasingly prevalent, and the underlying pathogenesis of obesity is complex and needs to be researched further. In this study, we report a decreased expression of let-7a-5p in the white adipose tissue (WAT) of animals with obesity. Using the RNA oligo, let-7a-5p over-expression or suppression-expression is achieved, impacting the proliferation and differentiation of preadipocytes in vitro. Srebf2 mechanistically interacts with the metabolic effect of let-7a-5p and participates in lipid accumulation by regulating Srebf2 downstream signaling. Moreover, let-7a-5p binds to Thbs1 to interact with the PI3K-AKT-mTOR pathway, down-regulating the phosphorylation levels of AKT, mTOR, and S6K1 to decrease lipid accumulation. In conclusion, our study highlights the physiological significance of let-7a-5p in lipid accumulation and suggests that the let-7a-5p/Srebf2 and let-7a-5p/Thbs1/PI3K-AKT-mTOR axes may represent potential mechanisms for controlling lipid accumulation in obesity.

p53 deficient breast cancer cells reprogram preadipocytes toward tumor-protective immunomodulatory cells

The TP53 gene is mutated in approximately 30% of all breast cancer cases. Adipocytes and preadipocytes, which constitute a substantial fraction of the stroma of normal mammary tissue and breast tumors, undergo transcriptional, metabolic, and phenotypic reprogramming during breast cancer development and play an important role in tumor progression. We report here that p53 loss in breast cancer cells facilitates the reprogramming of preadipocytes, inducing them to acquire a unique transcriptional and metabolic program that combines impaired adipocytic differentiation with augmented cytokine expression. This, in turn, promotes the establishment of an inflammatory tumor microenvironment, including increased abundance of Ly6C+ and Ly6G+ myeloid cells and elevated expression of the immune checkpoint ligand PD-L1. We also describe a potential gain-of-function effect of common p53 missense mutations on the inflammatory reprogramming of preadipocytes. Altogether, our study implicates p53 deregulation in breast cancer cells as a driver of tumor-supportive adipose tissue reprogramming, expanding the network of non-cell autonomous mechanisms whereby p53 dysfunction may promote cancer. Further elucidation of the interplay between p53 and adipocytes within the tumor microenvironment may suggest effective therapeutic targets for the treatment of breast cancer patients.

Creeping fat exhibits distinct Inflammation-specific adipogenic preadipocytes in Crohn's disease

Creeping fat (CrF) is an extraintestinal manifestation observed in patients with Crohn's disease (CD). It is characterized by the accumulation of mesenteric adipose tissue (MAT) that wraps around the intestinal wall. Although the role of CrF in CD is still debated, multiple studies have highlighted a correlation between CrF and inflammation, as well as fibrostenosais of the intestine, which contributes to the worsening of CD symptoms. However, the mechanism underlying the potential role of CrF in the development of Crohn's fibrosis remains an enigma. This study aimed to analyze CrF comprehensively using single-cell RNA sequencing analysis. The data was compared with transcriptomic data from adipose tissue in other disease conditions, such as ulcerative colitis, lymphedema, and obesity. Our analysis classified two lineages of preadipocyte (PAC) clusters responsible for adipogenesis and fibrosis in CrF. Committed PACs in CrF showed increased cytokine expression in response to bacterial stimuli, potentially worsening inflammation in patients with CD. We also observed an increase in fibrotic activity in PAC clusters in CrF. Co-analyzing the data from patients with lymphedema, we found that pro-fibrotic PACs featured upregulated pentraxin-3 expression, suggesting a potential target for the treatment of fibrosis in CrF. Furthermore, PACs in CrF exhibited a distinct increase in cell-to-cell communication via cytokines related to inflammation and fibrosis, such as CCL, LIGHT, PDGF, MIF, and SEMA3. Interestingly, these interactions also increased in PACs of the lymphedema, whereas the increased MIF signal of PACs was found to be a distinct characteristic of CrF. In immune cell clusters in CrF, we observed high immune activity of pro-inflammatory macrophages, antigen-presenting macrophages, B cells, and IgG+ plasma cells. Finally, we have demonstrated elevated IgG+ plasma cell infiltration and increased pentraxin-3 protein levels in the fibrotic regions of CrF in CD patients when compared to MAT from both UC patients and healthy individuals. These findings provide new insights into the transcriptomic features related to the inflammation of cells in CrF and suggest potential targets for attenuating fibrosis in CD.

miR-15a regulates the preadipocyte differentiation by targeting ABAT gene in Yanbian yellow cattle

MicroRNAs (miRNAs) are small, single-stranded, noncoding RNAs of approximately 21 to 23 nucleotides in length. Owing to their regulation of gene expression and many physiological processes including fat metabolism, they have become a popular research topic in recent years; however, the exact functional mechanisms by which they regulate fat metabolism have not been fully elucidated. Here, we identified miR-15a, which specifically acquired the 3' untranslated region (UTR) containing 4-aminobutyrate aminotransferase (ABAT), and validated the regulation of its expression and involvement in adipogenesis mechanisms. We used a dual-luciferase reporter assay and transfection-mediated miR-15a overexpression and inhibition in Yanbian yellow cattle preadipocytes to investigate the role of miR-15a in adipogenesis. The results showed that miR-15a directly targets the 3'UTR of ABAT and downregulates its expression. Additionally, at the protein and mRNA levels, miR-15a overexpression using a miRNA mimic inhibited triglyceride accumulation and downregulated lipogenic peroxisome proliferator-activated receptor γ and CCAAT enhancer-binding protein α, whereas miR-15a inhibition had the opposite effect. The above results indicated that miR-15a regulated the differentiation of Yanbian yellow cattle preadipocytes by inhibiting the expression of ABAT. Furthermore, our findings suggested that miR-15a and its target gene(s) might represent new targets for investigating intramuscular fat deposits in cattle and treating human obesity.

Cloning of goat PGAM2 gene and its overexpression promotes the differentiation of intramuscular preadipocytes

As a member of the PGAMs family, PGAM2 has been proved to catalyze the reversible reaction of 3-phosphoglycerate (3-PGA) to 2-phosphoglycerate (2-PGA) in the glycolytic pathway. However, it is unclear whether PGAM2 has a role in regulating differentiation in goat intramuscular preadipocytes. Here, this study was carried to clone the open reading frame (ORF) of goat PGAM2, elucidate its molecular and expressional characteristics, and evaluate the involvement in adipogenesis of intramuscular preadipocytes. According to our findings, the cloned goat PGAM2 gene was 784 bp in full length, including 762 bp of ORF and encoding a protein of 253 amino acids. The expressional level of PGAM2 peaked at 48 hours after induced adipogenic differentiation and was highest in the skeletal muscle of triceps. Moreover, overexpression of PGAM2 transfected by its overexpression plasmid promotes lipid accumulation of goat intramuscular adipocyte as shown by Oil Red O and bodipy staining, accompanied by up-regulating the mRNA levels of peroxisome proliferator-activated receptor γ (PPARγ) (p < 0.001), sterol regulatory element-binding protein 1 (SREBP1) (p < 0.001), CCAAT/Enhancer-binding protein α (C/EBPα) (p < 0.01) and lipoprotein lipase (LPL) (p < 0.01). Taken together, these findings indicate that PGAM2 is a positive regulator for goat intramuscular adipocytes and provide new insights into improvement intramuscular fat deposition in goat meat.

Histological characteristics of hair follicles at different hair cycle and in vitro modeling of hair follicle-associated cells of yak (Bos grunniens)

To adapt to the extreme conditions of plateau environments, yaks have evolved thick hair, making them an ideal model for investigating the mechanisms involved in hair growth. We can gain valuable insights into how hair follicles develop and their cyclic growth in challenging environments by studying yaks. However, the lack of essential data on yak hair follicle histology and the absence of in vitro cell models for hair follicles serve as a limitation to such research objectives. In this study, we investigated the structure of skin tissue during different hair follicle cycles using the yak model. Additionally, we successfully established in vitro models of hair follicle-associated cells derived from yak skin, including dermal papilla cells (DPCs), preadipocytes, and fibroblasts. We optimized the microdissection technique for DPCs culture by simplifying the procedure and reducing the time required. Furthermore, we improved the methodology used to differentiate yak preadipocytes into mature adipocytes, thus increasing the differentiation efficiency. The introduction of yak as a natural model provides valuable research resources for exploring the mechanisms of hair growth and contributes to a deeper understanding of hair follicle biology and the development of regenerative medicine strategies.

Dietary dibutyryl cAMP supplementation regulates the fat deposition in adipose tissues of finishing pigs via cAMP/PKA pathway

This study investigated potential mechanism of dibutyryl-cAMP (db-cAMP) on porcine fat deposition. (1) Exp.1, 72 finishing pigs were allotted to 3 treatments (0, 10 or 20 mg/kg dbcAMP) with 6 replicates. dbcAMP increased the hormone sensitive lipase (HSL) activity and expression of β-adrenergic receptor (β-AR) and growth hormone receptor (GHR), but decreased expression of peroxisome proliferator-activated receptor gamma 2 (PPAR-γ2) and adipocyte fatty acid binding protein (A-FABP) in back fat. dbcAMP upregulated expression of β-AR, GHR, PPAR-γ2 and A-FABP, but decreased insulin receptor (INSR) expression in abdominal fat. Dietary dbcAMP increased HSL activity and expression of G protein-coupled receptor (GPCR), cAMP-response element-binding protein (CREB) and insulin-like growth factor-1 (IGF-1), but decreased fatty acid synthase (FAS) and lipoprotein lipase (LPL) activities, and expression of INSR, cAMP-response element-binding protein (C/EBP-α) and A-FABP in perirenal fat. (2) Exp. 2, dbcAMP suppressed the proliferation and differentiation of porcine preadipocytes in a time- and dose-dependent manner, which might be associated with increased activities of cAMP and protein kinase A (PKA), and expression of GPCR, β-AR, GHR and CREB via inhibiting C/EBP-α and PPAR-γ2 expression. Collectively, dbcAMP treatment may reduce fat deposition by regulating gene expression related to adipocyte differentiation and fat metabolism partially via cAMP-PKA pathway.

Knockdown of KLF7 inhibits the differentiation of both intramuscular and subcutaneous preadipocytes in goat

KLF7 belongs to the Krüppel-like factors (KLFs) family, which function as transcriptional regulators controlling a number of basic cellular processes, involving proliferation, differentiation, and migration. Here, we reveal insights into the differentiated expression of KLF7 in different goat tissues and different stages of growth, and the inhibition role of KLF7 knockdown to differentiation by using goat intramuscular and subcutaneous preadipocytes. We demonstrate that KLF7 expression is obviously changed during the differentiation of preadipocytes into mature adipocytes. Knockdown of KLF7 inhibited lipid droplet accumulation, reduced the expression of adipogenic markers both in intramuscular and subcutaneous preadipocytes in goats, suggesting that KLF7 is a novel regulator of adipogenesis. KLF7 expression changed also up or down-regulation the other KLF family members, but there were differences between these two types of cells. Investigation into the mechanism that KLF7 regulates preadipocyte differentiation revealed that KLF family members KLF1, KLF5, KLF6, KLF8, KLF11, KLF12, KLF16, KLF17 and adipogenic markers C/EBPα and SREBP1 promoter region present KLF7 transcriptional binding sites. Altogether, the data here identify KLF7 as a novel regulator of adipogenesis.

lncRNA MSTRG4710 Promotes the Proliferation and Differentiation of Preadipocytes through miR-29b-3p/IGF1 Axis

Obesity, a major global health issue, is increasingly associated with the integral role of long non-coding RNA (lncRNA) in adipogenesis. Recently, we found that lncRNA-MSTRG4710 was highly expressed in the liver of rabbits fed a high-fat diet, but whether it is involved in lipid metabolism remains unclear. A series of experiments involving CCK-8, EDU, qPCR, and Oil Red O staining demonstrated that the overexpression of MSTRG4710 stimulated the proliferation and differentiation of preadipocytes while its knockdown inhibited these processes. Bioinformatics analysis showed that miR-29b-3p was a potential target gene of MSTRG4710, and IGF1 was a downstream target gene of miR-29b-3p. Luciferase reporter gene analysis and qPCR analysis confirmed that miR-29b-3p was a potential target gene of MSTRG4710, and miR-29b-3p directly targeted the 3'UTR of IGF1. The overexpression of miR-29b-3p was observed to regulate IGF1 protein and mRNA levels negatively. Additionally, a total of 414 known differentially expressed genes between the miR-29b-3p mimic, miR-29b-3p negative control (NC), siMSTRG4710, and siMSTRG4710-NC group were screened via transcriptome sequencing technology. The GO- and KEGG-enriched pathways were found to be related to lipid metabolism. The study also established that miR-29b-3p targets IGF1 to inhibit preadipocyte proliferation and differentiation. Notably, IGF1 knockdown significantly reduced preadipocyte proliferation and differentiation. Furthermore, co-transfection of pcDNA3.1(+)-MSTRG4710 and mimics into rabbit preadipocytes revealed that the mimics reversed the promotional effect of pcDNA3.1(+)-MSTRG4710. In conclusion, these results uncover that MSTRG4710 positively regulated cell proliferation and adipogenesis by the miR-29b-3p/IGF1 axis. Our findings might provide a new target for studying adipogenesis in rabbit preadipocytes and obesity.

Chrysin inhibits adipogenesis by modulating PPARγ: in silico and in vitro studies

Adipose tissue is the major storage site of lipids and plays a vital role in energy homeostasis. Adipogenesis is a well-regulated process wherein preadipocytes differentiate into adipocytes. It requires the sequential activation of numerous transcription factors, including peroxisome proliferator activated receptor-γ (PPAR-γ). Phytochemicals have been reported to regulate adipogenesis and flavonoids represent the most researched groups of phytochemicals with regard to their effect on adipogenesis. Chrysin is a naturally occurring flavone and is reported to have anti-inflammatory effects in obese conditions. The present study was aimed to examine the effect of chrysin on adipogenesis. In silico Molecular docking, dynamic simulation studies and in vitro cell-based assays showed that chrysin inhibited adipogenesis by modulating key adipogenic transcription factor PPARγ. Enhanced adipogenesis leads to obesity and targeting adipogenesis is potential in regulating adipose tissue development. So, these investigations may provide important information for designing therapeutic interventions to control adiposity.Communicated by Ramaswamy H. Sarma.

miR-383-5p Regulates Preadipocyte Proliferation and Differentiation by Targeting RAD51AP1

Obesity has become a major health problem worldwide, and increasing evidence supports the importance of microRNAs (miRNAs) in its pathogenesis. Recently, we found that miR-383-5p_1 is highly expressed in the perirenal fat of high-fat-fed rabbits, but it is not yet known whether miR-383-5p is involved in lipid metabolism. Here, we used transcriptome sequencing technology to screen 1642 known differentially expressed genes between miR-383-5p mimic groups and miR-383-5p negative control groups. Gene Ontology Resource (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were enriched in the pathway related to lipid metabolism, and glycine biosynthesis, the NOD receptor signal pathway and nonalcoholic fatty liver were significantly enriched. Afterwards, our research results indicated that miR-383-5p can promote the proliferation and differentiation of rabbit preadipocytes, and there is a direct targeting relationship with RAD51AP1. Mechanistically, miR-383-5p directly interacts with the lipid metabolism and participates in adipogenesis and lipid accumulation by targeting RAD51AP1. In conclusion, our data highlight a physiological role for miRNA in lipid metabolism and suggest the miR-383-5p/RAD51AP1 axis may represent a potential mechanism for controlling lipid accumulation in obesity.

miR-125a-3p regulates the expression of FSTL1, a pro-inflammatory factor, during adipogenic differentiation, and inhibits adipogenesis in mice

Adipogenesis is tightly regulated by various factors, including genes and microRNAs. Excessive fat deposition is the key feature of obesity, which is a low-grade chronic inflammatory disease. Follistatin-like 1 (FSTL1) has been reported to be an important mediator involved in various inflammatory diseases. However, the underlying mechanism of FSTL1 in preadipocyte differentiation and inflammatory response is still unclear. The current study was designed to explore the biological function and potential mechanism of FSTL1 in mouse subcutaneous preadipocyte differentiation. We found that FSTL1 was highly expressed in the early stage of differentiation and subsequently decreased sharply, suggesting that FSTL1 played a possible role in adipogenesis. Meanwhile, the gain- and loss-of-function assays showed that FSTL1 was not only involved in the inflammatory response by inducing the expression of pro-inflammatory factors IL-1β and CCL2 but also significantly attenuated preadipocyte differentiation, as evidenced by the reduction of lipid accumulation and the levels of adipogenic genes, including PPARγ and FABP4. In addition, the target gene prediction and luciferase reporter assay validated that miR-125a-3p targeted the 3' UTR region of FSTL1. These results demonstrated that miR-125a-3p negatively regulated the expression of FSTL1 at the mRNA and protein levels. Furthermore, overexpressing miR-125a-3p in preadipocytes dramatically accelerated adipogenic differentiation and downregulated the levels of IL-1β and CCL2, which were in accordance with the knockdown of FSTL1. On the contrary, treatment with miR-125a-3p inhibitors attenuated adipogenesis but induced the expression of inflammatory genes. In summary, this study suggests a positive function of FSTL1 in adipocyte-induced inflammation and negatively regulates preadipocyte differentiation. Further studies demonstrated that miR-125a-3p could reverse the effect by targeting FSTL1, which might provide a better understanding of treating obesity-related inflammatory diseases.

Conservation of Markers and Stemness in Adipose Stem and Progenitor Cells between Cattle and Other Species

Adipose stem and progenitor cells (ASPCs) have been isolated from humans and animals for use in regenerative medicine and therapy. However, knowledge of ASPCs in other species is limited. Particularly, ASPCs in livestock are expected to enhance the fat content and meat composition. In this study, we isolated bovine ASPCs using cell surface markers. Specifically, we focused on ASPC markers in humans and experimental animals, namely CD26, CD146, and CD54. Stromal vascular fraction cells from bovine fat were separated using flow cytometry before primary culture. We evaluated the self-renewal and adipogenic potential of each fraction. We identified four cell populations: CD26-CD146+CD54+, CD26-CD146+CD54-, CD26-CD146-, and CD26+CD146-. Among them, the CD26-CD146+ fraction, particularly CD54+, demonstrated the properties of preadipocytes (PreAs), characterized by slow proliferation and a high adipogenic capacity. In conclusion, we could collect and characterize possible PreAs as CD26-CD146+CD54+ or CD26-CD146+CD54-, which are expected for in vitro bovine adipogenic assays in the future.

The Effects of Neuropeptide B on Proliferation and Differentiation of Porcine White Preadipocytes into Mature Adipocytes

Neuropeptide B (NPB) affects energy homeostasis and metabolism by binding and activating NPBWR1 and NPBWR2 in humans and pigs. Recently, we reported that NPB promotes the adipogenesis of rat white and brown preadipocytes as well as 3T3-L1 cells. In the present study, we evaluated the effects of NPB on the proliferation and differentiation of white porcine preadipocytes into mature adipocytes. We identified the presence of NPB, NPBWR1, and NPBWR2 on the mRNA and protein levels in porcine white preadipocytes. During the differentiation process, NPB increased the mRNA expression of PPARγ, C/EBPβ, C/EBPα, PPARγ, and C/EBPβ protein production in porcine preadipocytes. Furthermore, NPB stimulated lipid accumulation in porcine preadipocytes. Moreover, NPB promoted the phosphorylation of the p38 kinase in porcine preadipocytes, but failed to induce ERK1/2 phosphorylation. NPB failed to stimulate the expression of C/EBPβ in the presence of the p38 inhibitor. Taken together, we report that NPB promotes the differentiation of porcine preadipocytes via a p38-dependent mechanism.

Adipose tissue at single-cell resolution

Adipose tissue exhibits remarkable plasticity with capacity to change in size and cellular composition under physiological and pathophysiological conditions. The emergence of single-cell transcriptomics has rapidly transformed our understanding of the diverse array of cell types and cell states residing in adipose tissues and has provided insight into how transcriptional changes in individual cell types contribute to tissue plasticity. Here, we present a comprehensive overview of the cellular atlas of adipose tissues focusing on the biological insight gained from single-cell and single-nuclei transcriptomics of murine and human adipose tissues. We also offer our perspective on the exciting opportunities for mapping cellular transitions and crosstalk, which have been made possible by single-cell technologies.

Membrane Protein Amuc_1100 Derived from Akkermansia muciniphila Facilitates Lipolysis and Browning via Activating the AC3/PKA/HSL Pathway

Obesity, defined as a disorder of lipid metabolism caused by white fat accumulation, is closely related to the gut microbiota. Akkermansia muciniphila (Akk), one of the most common gut commensals, can reduce fat storage and promote the browning of white adipocytes, alleviating disorders of lipid metabolism. However, which components of Akk produce the effect remain unclear, limiting the application of Akk in the treatment of obesity. Here, we found that the membrane protein Amuc_1100 of Akk decreased formation of lipid droplets and fat accumulation during the differentiation process and stimulated browning in vivo and in vitro. Transcriptomics revealed that Amuc_1100 accelerated lipolysis through upregulation of the AC3/PKA/HSL pathway in 3T3-L1 preadipocytes. Quantitative PCR (qPCR) and Western blotting showed that Amuc_1100 intervention promotes steatolysis and browning of preadipocytes by increasing lipolysis-related genes (AC3/PKA/HSL) and brown adipocyte marker genes (PPARγ, UCP1, and PGC1α) at both the mRNA and protein levels. These findings introduce new insight into the effects of beneficial bacteria and provide new avenues for the treatment of obesity. IMPORTANCE An important intestinal bacterial strain Akkermansia muciniphila contributes to improving carbohydrate and lipid metabolism, thus alleviating obesity symptoms. Here, we find that the Akk membrane protein Amuc_1100 regulates lipid metabolism in 3T3-L1 preadipocytes. Amuc_1100 inhibits lipid adipogenesis and accumulation during the differentiation process of preadipocytes, upregulates the browning-related genes of preadipocytes, and promotes thermogenesis through activation of uncoupling protein-1 (UCP-1), including Acox1 involved in lipid oxidation. Amuc_1100 accelerates lipolysis via the AC3/PKA/HSL pathway, phosphorylating HSL at Ser 660. The experiments illustrated here identify the specific molecules and functional mechanisms of Akk. Therapeutic approaches with Amuc_1100 derived from Akk may help alleviate obesity and metabolic disorders.

Inhibition Effect of Adipogenesis and Lipogenesis via Activation of AMPK in Preadipocytes Treated with Canavalia gladiata Extract

The aim of this study was to investigate the effect of Canavalia gladiata extract (CGE) on the regulation of AMP-activated protein kinase (AMPK) in 3T3-L1 preadipocytes and evaluate the adipogenesis and lipogenesis mechanisms. In 3T3-L1 preadipocytes, lipid accumulation and differentiation were suppressed by 1.1, 1.3, and 1.4 times under the CGE treatment at 0.25, 0.5, and 1.0 mg/mL, respectively. The expression of the main genes involved in the inhibition of adipogenesis was evaluated at the mRNA level via a transcription-polymerase chain reaction. The extract at 1.0 mg/mL increased the mRNA expressions of AMPK and carnitine palmitoyl transferase-1 (CPT-1) by 1.9 and 1.2 times, respectively, while it decreased the expression of sterol regulatory element binding proteins-1c (SREBP-1c), peroxisome proliferator activated receptor-γ (PPAR-γ), CCAAT enhancer binding protein-α (C/EBP-α), and fatty acid synthase (FAS) by 1.1, 1.2, 1.8, and 1.5 times, respectively, indicating inhibition of the adipogenesis and lipogenesis potential of CGE. Gallic acid (4.02 mg/g) was identified as the main component of the CGE via LC-MS/MS and HPLC analysis. The results of this study suggested that CGE can be utilized as an anti-obesity food additive or medication by activating the AMPK-induced regulation and suppressing adipogenesis transcription factors.

Analysis of the different characteristics between omental preadipocytes and differentiated white adipocytes using bioinformatics methods

Obesity is emerging as an epidemiological issue, being associated with the onset and progress of various metabolism-related disorders. Obesity is characterized by the white adipose expansion, which encounters white adipocyte hypertrophy and hyperplasia. White adipocyte hyperplasia is defined as adipogenesis with the increase in the number of the white adipocytes from the preadipocytes. Adipogenesis contributes to distributing excess triglycerides among the smaller newly formed adipocytes, reducing the number of hypertrophic adipocytes and secreting anti-inflammatory factor. Therefore, adipogenesis is emerging as a new therapeutic target for the treatment of obesity. In the present study, for a better understanding of the contribution of the alteration of the omental differentiated white adipocytes to the systemic metabolic disorders, we downloaded the mRNA expression profiles from GEO database GSE1657, 328 differentially expressed genes (DEGs) were screened between the undifferentiated preadipocytes (UNDIF) and omental differentiated white adipocytes (DIF). The contributions of the upregulated and downregulated DEGs to the system were performed via the Gene Ontology (GO) analysis, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and Protein-Protein Interaction (PPI) network, respectively. The potential contribution of the whole altered genes in the differentiated white adipocytes was explored with the performance of Gene Set Enrichment Analysis (GSEA), especially on the GO analysis, KEGG analysis, hallmark analysis, oncogenic analysis and related miRNA analysis. The output of the current study will shed light on the new targets for the treatment of obesity and obesity-related disorders.

Effect of sera from elite athletes on cytokine secretion and insulin signaling in preadipocytes and skeletal muscle cells

Introduction: The immunomodulatory effect of physical activity can impact insulin signaling differentially in adipose tissues and skeletal muscle cells, depending on sport intensity. In this study, the effect of serum from elite athletes with varying endurance levels and playing different power sports on cytokine secretion and insulin signaling in preadipocyte and skeletal muscle cell lines was investigated. Methods: Preadipocytes (3T3-L1) and skeletal muscle cells (C2C12) were cultured in media containing pooled sera from elite athletes who play high-endurance (HE), high-power (HP), or low-endurance/low-power (LE/LP) sports for 72 h. Secreted cytokines (IL-6 and TNF-alpha) were assessed in the supernatant, and insulin signaling phosphoproteins levels were measured in lysates following treatment using cells multiplex immunoassays. Results: Sera from LE/LP and HP induced TNF-α secretion in C2C12, while serum from HE reduced IL-6 secretion compared to non-athlete serum control. All elite athlete sera groups caused decreased insulin sensitivity in 3T3-L1 cells, whereas in C2C12 cells, only HE athlete serum reduced insulin signaling, while LE/LP and HP caused increased insulin sensitivity. Conclusion: Sera from elite athletes of different sport disciplines can affect the inflammatory status and insulin signaling of preadipocytes and myoblasts differently, with risk of developing insulin resistance. Furthermore, investigation of the functional relevance of these effects on exercise physiology and pathophysiology is warranted.

Reassessment of adipocyte technology for cellular agriculture of alternative fat

Alternative proteins, such as cultivated meat, have recently attracted significant attention as novel and sustainable food. Fat tissue/cell is an important component of meat that makes organoleptic and nutritional contributions. Although adipocyte biology is relatively well investigated, there is limited focus on the specific techniques and strategies to produce cultivated fat from agricultural animals. In the assumed standard workflow, stem/progenitor cell lines are derived from tissues of animals, cultured for expansion, and differentiated into mature adipocytes. Here, we compile information from literature related to cell isolation, growth, differentiation, and analysis from bovine, porcine, chicken, other livestock, and seafood species. A diverse range of tissue sources, cell isolation methods, cell types, growth media, differentiation cocktails, and analytical methods for measuring adipogenic levels were used across species. Based on our analysis, we identify opportunities and challenges in advancing new technology era toward producing "alternative fat" that is suitable for human consumption.

Oar-miR-432 Regulates Fat Differentiation and Promotes the Expression of BMP2 in Ovine Preadipocytes

The fat tail is a unique characteristic of sheep that represents energy reserves and is a complex adaptative mechanism of fat-tailed sheep to environmental stress. MicroRNA plays a significant role as regulators at the posttranscriptional level, but no studies have explained the molecular mechanisms of miRNA which regulate fat deposition in sheep tails. In this study, mRNA and miRNA analysis examined tail fat tissue from three Hu fat-tailed and three Tibetan thin-tailed sheep. After aligning to the reference sequences, 2,108 differentially expressed genes and 105 differential expression miRNAs were identified, including 1,247 up- and 861 downregulated genes and 43 up- and 62 downregulated miRNAs. Among these differentially expressed miRNAs, oar-miR-432 was one of the most downregulated miRNAs between Hu sheep and Tibetan sheep, and 712 genes were predicted to be targeted by oar-miR-432, 80 of which overlapped with DEGs. The Gene Ontology analysis on these genes showed that BMP2, LEP, GRK5, BMP7, and RORC were enriched in fat cell differentiation terms. The genes for BMP2 targeted by oar-miR-432 were examined using dual-luciferase assay. The oar-miR-432 mimic transfected into preadipocytes resulted in increased expression of BMP2. The marker gene PPAR-γ of fat differentiation had a lower expression than the negative control on days 0, 2, and 4 after induced differentiation. The decrease in the number of lipids in the oar-miR-432 mimic group detected by oil red O stain was also less than that in the negative control. This is the first study to reveal the fat mechanisms by which oar-miR-432 inhibits fat differentiation and promotes the expression of BMP2 in sheep tails.

TCDD-inducible Poly (ADP-ribose) Polymerase Promotes Adipogenesis of Both Brown and White Preadipocytes

Background

TCDD-inducible poly (ADP-ribose) polymerase (TiPARP) is a DNA repair enzyme with functions in energy metabolism, signal transduction, cell differentiation, and other biological processes, which may closely related to lipid metabolism and is highly expressed in adipose tissue. Adipose tissue can be divided into white adipose tissue (WAT) that stores energy and brown adipose tissue (BAT) that releases energy and generates heat. In the present study, we investigated whether TiPARP can affect adipogenesis in adipose tissue and thus participate in the development of obesity.

Methods

BAT primary cells or 3T3-L1 cells infected with adenovirus expressing TiPARP or TiPARP-targeted short hairpin RNA (shTiPARP) were cultured to induce adipogenic differentiation. The expression of TiPARP was detected by real-time PCR and Western blotting. The expression of specific BAT- and WAT-related markers was detected by real-time PCR. The accumulation of lipid droplets in differentiated cells was detected by Oil Red O staining.

Results

TiPARP was highly expressed in both subcutaneous WAT and BAT, and TiPARP mRNA level increased significantly along with adipogenic differentiation. Activation of TiPARP or overexpression of TiPARP upregulated BAT-related markers in primary BAT cells and WAT-related markers in 3T3-L1 cells, together with increased lipid accumulation. On the contrary, knockdown of TiPARP downregulated expression of specific markers in both BAT primary cells and 3T3-L1 cells, together with decreased lipid accumulation.

Conclusion

TiPARP regulates adipogenesis in both BAT primary cells and 3T3-L1 cells and therefore plays an important role in modulating maturity and lipid accumulation in brown and white adipocytes. These findings provide us with a new strategy for combating obesity.

Theophylline Extracted from Fu Brick Tea Affects the Metabolism of Preadipocytes and Body Fat in Mice as a Pancreatic Lipase Inhibitor

The dramatic increase in obesity is putting people under increasing pressure. Lipase inhibitors, as a kind of effective anti-obesity drug, have attracted more and more researchers’ attention in recent years because of their advantages of acting on the intestinal tract and having no side effects on the central nervous system. In this study, lipase inhibitor Fu Brick Theophylline (FBT) was screened based on enzyme molecular dynamics, and the inhibition mechanism of lipase inhibitors on obesity was analyzed and discussed at the cellular level and animal model level. We found that FBT had high inhibition effects of lipase with an IC₅₀ of 1.02~0.03 μg/mL. Firstly, the laboratory used 3T3-L1 proadipocytes as models, flow cytometry was used to detect the effects of FBT on the cycle, apoptosis and intracellular ROS activity of proadipocytes. To study the contents of triglyceride, total cholesterol, related metabolites and related gene and protein expression in adipocytes. The results showed that FBT could reduce ROS production and inflammatory factor mRNA expression during cell differentiation. Secondly, by establishing the animal model of high-fat feed ob nutritional obese mice, the morphological observation and gene expression analysis of body weight, fat rate, adipocyte and hepatocyte metabolism of FBT obese mice were further discussed. It was proven that FBT can effectively reduce the degree of fatty liver, prevent liver fibrosis and fat accumulation, and improve the damage of mitochondrial membrane structure. This study provides a theoretical basis for the screening and clinical treatment of lipase inhibitors.

PIEZO1 mechanoreceptor activation reduces adipogenesis in perivascular adipose tissue preadipocytes

During hypertension, vascular remodeling allows the blood vessel to withstand mechanical forces induced by high blood pressure (BP). This process is well characterized in the media and intima layers of the vessel but not in the perivascular adipose tissue (PVAT). In PVAT, there is evidence for fibrosis development during hypertension; however, PVAT remodeling is poorly understood. In non-PVAT depots, mechanical forces can affect adipogenesis and lipogenic stages in preadipocytes. In tissues exposed to high magnitudes of pressure like bone, the activation of the mechanosensor PIEZO1 induces differentiation of progenitor cells towards osteogenic lineages. PVAT's anatomical location continuously exposes it to forces generated by blood flow that could affect adipogenesis in normotensive and hypertensive states. In this study, we hypothesize that activation of PIEZO1 reduces adipogenesis in PVAT preadipocytes. The hypothesis was tested using pharmacological and mechanical activation of PIEZO1. Thoracic aorta PVAT (APVAT) was collected from 10-wk old male SD rats (n=15) to harvest preadipocytes that were differentiated to adipocytes in the presence of the PIEZO1 agonist Yoda1 (10 µM). Mechanical stretch was applied with the FlexCell System at 12% elongation, half-sine at 1 Hz simultaneously during the 4 d of adipogenesis (MS+, mechanical force applied; MS-, no mechanical force used). Yoda1 reduced adipogenesis by 33% compared with CON and, as expected, increased cytoplasmic Ca2+ flux. MS+ reduced adipogenesis efficiency compared with MS-. When Piezo1 expression was blocked with siRNA [siPiezo1; NC=non-coding siRNA], the anti-adipogenic effect of Yoda1 was reversed in siPiezo1 cells but not in NC; in contrast, siPiezo1 did not alter the inhibitory effect of MS+ on adipogenesis. These data demonstrate that PIEZO1 activation in PVAT reduces adipogenesis and lipogenesis and provides initial evidence for an adaptive response to excessive mechanical forces in PVAT during hypertension.

Effect of Actin Alpha Cardiac Muscle 1 on the Proliferation and Differentiation of Bovine Myoblasts and Preadipocytes

Simple Summary

Marbling is an important factor affecting the quality of beef. The co-culture (myoblast-preadipocytes) system was successfully established in our lab in the early stage to simulate the internal environment of marbling. Within this environment, ACTC1 gene was a differentially expressed gene screened from the co-culture system. The gene was not expressed in monocultured adipocytes but was expressed in co-cultured adipocytes. Therefore, we hypothesize that the ACTC1 gene plays a role in the development of bovine myoblasts and preadipocytes. In this study, we explored the effect of ACTC1 gene on the proliferation and differentiation of bovine myoblasts and preadipocytes, aiming to discover the potential biological function of ACTC1 gene in muscle development and fat deposition. The results showed that ACTC1 could regulate the development of bovine myoblasts and preadipocytes, and ACTC1 could be used as an important target for improving beef quality in the future.

Abstract

Actin Alpha Cardiac Muscle 1 (ACTC1) gene is a differentially expressed gene screened through the co-culture system of myoblasts-preadipocytes. In order to study the role of this gene in the process of proliferation and differentiation of bovine myoblasts and preadipocytes, the methods of the knockdown, overexpression, and ectopic expression of ACTC1 were used in this study. After ACTC1 knockdown in bovine myoblasts and inducing differentiation, the sizes and numbers of myotube formation were significantly reduced compared to the control group, and myogenic marker genes—MYOD1, MYOG, MYH3, MRF4, MYF5, CKM and MEF2A—were significantly decreased (p < 0.05, p < 0.01) at both the mRNA and protein levels of myoblasts at different differentiation stages (D0, D2, D4, D6 and D8). Conversely, ACTC1 overexpression induced the inverse result. After ectopic expression of ACTC1 in bovine preadipocytes and induced differentiation, the number and size of lipid droplets were significantly higher than those of the control group, and the expression of adipogenic marker genes—FABP4, SCD1, PPARγ and FASN—were significantly increased (p < 0.05, p < 0.01) at the mRNA and protein levels of preadipocytes at different differentiation stages. Flow cytometry results showed that both the knockdown and overexpression of ACTC1 inhibited the normal cell cycle of myoblasts; however, ectopic expression of ACTC1 in adipocytes induced no significant cell cycle changes. This study is the first to explore the role of ACTC1 in bovine myogenesis and lipogenesis and demonstrates that ACTC1 promotes the differentiation of bovine myoblasts and preadipocytes, affecting the proliferation of myoblasts.

Impaired mRNA splicing and proteostasis in preadipocytes in obesity-related metabolic disease

Preadipocytes are crucial for healthy adipose tissue expansion. Preadipocyte differentiation is altered in obese individuals, which has been proposed to contribute to obesity-associated metabolic disturbances. Here, we aimed at identifying the pathogenic processes underlying impaired adipocyte differentiation in obese individuals with insulin resistance (IR)/type 2 diabetes (T2D). We report that down-regulation of a key member of the major spliceosome, PRFP8/PRP8, as observed in IR/T2D preadipocytes from subcutaneous (SC) fat, prevented adipogenesis by altering both the expression and splicing patterns of adipogenic transcription factors and lipid droplet-related proteins, while adipocyte differentiation was restored upon recovery of PRFP8/PRP8 normal levels. Adipocyte differentiation was also compromised under conditions of endoplasmic reticulum (ER)-associated protein degradation (ERAD) hyperactivation, as occurs in SC and omental (OM) preadipocytes in IR/T2D obesity. Thus, targeting mRNA splicing and ER proteostasis in preadipocytes could improve adipose tissue function and thus contribute to metabolic health in obese individuals.

Ablation of KDM2A Inhibits Preadipocyte Proliferation and Promotes Adipogenic Differentiation

Epigenetic signals and chromatin-modifying proteins play critical roles in adipogenesis, which determines the risk of obesity and which has recently attracted increasing interest. Histone demethylase 2A (KDM2A) is an important component of histone demethylase; however, its direct effect on fat deposition remains unclear. Here, a KDM2A loss of function was performed using two unbiased methods, small interfering RNA (siRNA) and Cre-Loxp recombinase systems, to reveal its function in adipogenesis. The results show that the knockdown of KDM2A by siRNAs inhibited the proliferation capacity of 3T3-L1 preadipocytes. Furthermore, the promotion of preadipocyte differentiation was observed in siRNA-treated cells, manifested by the increasing content of lipid droplets and the expression level of adipogenic-related genes. Consistently, the genetic deletion of KDM2A by Adipoq-Cre in primary adipocytes exhibited similar phenotypes to those of 3T3-L1 preadipocytes. Interestingly, the knockdown of KDM2A upregulates the expression level of Transportin 1(TNPO1), which in turn may induce the nuclear translocation of PPARγ and the accumulation of lipid droplets. In conclusion, the ablation of KDM2A inhibits preadipocyte proliferation and promotes its adipogenic differentiation. This work provides direct evidence of the exact role of KDM2A in fat deposition and provides theoretical support for obesity therapy that targets KDM2A.

3D Adipose Tissue Culture Links the Organotypic Microenvironment to Improved Adipogenesis

Obesity and type 2 diabetes are strongly associated with adipose tissue dysfunction and impaired adipogenesis. Understanding the molecular underpinnings that control adipogenesis is thus of fundamental importance for the development of novel therapeutics against metabolic disorders. However, translational approaches are hampered as current models do not accurately recapitulate adipogenesis. Here, a scaffold-free versatile 3D adipocyte culture platform with chemically defined conditions is presented in which primary human preadipocytes accurately recapitulate adipogenesis. Following differentiation, multi-omics profiling and functional tests demonstrate that 3D adipocyte cultures feature mature molecular and cellular phenotypes similar to freshly isolated mature adipocytes. Spheroids exhibit physiologically relevant gene expression signatures with 4704 differentially expressed genes compared to conventional 2D cultures (false discovery rate < 0.05), including the concerted expression of factors shaping the adipogenic niche. Furthermore, lipid profiles of >1000 lipid species closely resemble patterns of the corresponding isogenic mature adipocytes in vivo (R2 = 0.97). Integration of multi-omics signatures with analyses of the activity profiles of 503 transcription factors using global promoter motif inference reveals a complex signaling network, involving YAP, Hedgehog, and TGFβ signaling, that links the organotypic microenvironment in 3D culture to the activation and reinforcement of PPARγ and CEBP activity resulting in improved adipogenesis.

DNA Methylation as a Marker of Body Shape in Premenopausal Women

Preferential accumulation of fat in the gluteo-femoral (GF) depot (pear shape) rather than in the abdominal (A) depot (apple shape), protects against the development of metabolic diseases but the underlying molecular mechanism is still unknown. Recent data, including our work, suggest that differential epigenetic marking is associated with regulation of genes attributed to distinct fat distribution. Here, we aimed to compare the genomic DNA methylation signatures between apple and pear-shaped premenopausal women. To investigate the contribution of upper and lower body fat, we used paired samples of A-FAT and GF-FAT, analyzed on the BeadChip Methylation Array and quantified the differentially methylated sites between the 2 groups of women. We found unique DNA methylation patterns within both fat depots that are significantly different depending on the body fat distribution. Around 60% of the body shape specific DNA methylation sites identified in adipose tissue are maintained ex vivo in cultured preadipocytes. As it has been reported before in other cell types, we found only a hand full of genes showing coordinated differential methylation and expression levels. Finally, we determined that more than 50% of the body shape specific DNA methylation sites could also be detected in whole blood derived DNA. These data reveal a strong DNA methylation program associated with adipose tissue distribution with the possibility that a simple blood test could be used as a predictive diagnostic indicator of young women who are at increased risk for progressing to the apple body shape with a higher risk of developing obesity related complications. Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT02728635 and https://clinicaltrials.gov/ct2/show/NCT02226640, identifiers NCT02728635 and NCT02226640.

A Metalloproteinase Induces an Inflammatory Response in Preadipocytes with the Activation of COX Signalling Pathways and Participation of Endogenous Phospholipases A2

Matrix metalloproteinases (MMPs) are proteolytic enzymes that have been associated with the pathogenesis of inflammatory diseases and obesity. Adipose tissue in turn is an active endocrine organ capable of secreting a range of proinflammatory mediators with autocrine and paracrine properties, which contribute to the inflammation of adipose tissue and adjacent tissues. However, the potential inflammatory effects of MMPs in adipose tissue cells are still unknown. This study investigates the effects of BmooMPα-I, a single-domain snake venom metalloproteinase (SVMP), in activating an inflammatory response by 3T3-L1 preadipocytes in culture, focusing on prostaglandins (PGs), cytokines, and adipocytokines biosynthesis and mechanisms involved in prostaglandin E₂ (PGE₂) release. The results show that BmooMPα-I induced the release of PGE₂, prostaglandin I₂ (PGI₂), monocyte chemoattractant protein-1 (MCP-1), and adiponectin by preadipocytes. BmooMPα-I-induced PGE₂ biosynthesis was dependent on group-IIA-secreted phospholipase A₂ (sPLA₂-IIA), cytosolic phospholipase A₂-α (cPLA₂-α), and cyclooxygenase (COX)-1 and -2 pathways. Moreover, BmooMPα-I upregulated COX-2 protein expression but not microsomal prostaglandin E synthase-1 (mPGES-1) expression. In addition, we demonstrate that the enzymatic activity of BmooMPα-I is essential for the activation of prostanoid synthesis pathways in preadipocytes. These data highlight preadipocytes as important targets for metalloproteinases and provide new insights into the contribution of these enzymes to the inflammation of adipose tissue and tissues adjacent to it.

Neuropeptide B promotes proliferation and differentiation of rat brown primary preadipocytes

Neuropeptide B (NPB) is reported to regulate energy homeostasis and metabolism via the NPBWR1 and NPBWR2 receptors in various tissues. However, the molecular mechanisms triggered from their interaction are not well investigated in brown adipose tissue. In this study, we specifically analyzed the role of NPB in controlling brown adipogenesis in rat brown preadipocytes. We first detected the expression of NPBWR1 and NPB on mRNA and protein level in brown preadipocytes and observed that NPB increased viability and proliferation of preadipocytes. Moreover, NPB stimulated expression of adipogenic genes (Prdm16, Ucp1) and suppressed the expression of antiadipogenic preadipocyte factor 1 (Pref1) during the differentiation process. Altogether, this led to an increase in intracellular lipid accumulation during preadipocyte differentiation, coupled with an increase in adrenaline‐induced oxygen consumption mediated by NPB. Furthermore, Ucp1 expression stimulated by NPB was attenuated by blockade of p38 kinase. In summary, we conclude that NPB promotes proliferation and differentiation of rat brown preadipocytes via p38‐dependent mechanism and plays an important role in controlling brown adipose tissue formation.

Signal Transducer and Activator of Transcription 3 (STAT3) Suppresses STAT1/Interferon Signaling Pathway and Inflammation in Senescent Preadipocytes

Obesity promotes premature aging and dysfunction of white adipose tissue (WAT) through the accumulation of cellular senescence. The senescent cells burden in WAT has been linked to inflammation, insulin-resistance (IR), and type 2 diabetes (T2D). There is limited knowledge about molecular mechanisms that sustain inflammation in obese states. Here, we describe a robust and physiologically relevant in vitro system to trigger senescence in mouse 3T3-L1 preadipocytes. By employing transcriptomics analyses, we discovered up-regulation of key pro-inflammatory molecules and activation of interferon/signal transducer and activator of transcription (STAT)1/3 signaling in senescent preadipocytes, and expression of downstream targets was induced in epididymal WAT of obese mice, and obese human adipose tissue. To test the relevance of STAT1/3 signaling to preadipocyte senescence, we used Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR associated protein 9 (CRISPR/Cas9) technology to delete STAT1/3 and discovered that STAT1 promoted growth arrest and cooperated with cyclic Guanosine Monophosphate-Adenosine Monophosphate (GMP-AMP) synthase-stimulator of interferon genes (cGAS-STING) to drive the expression of interferon β (IFNβ), C-X-C motif chemokine ligand 10 (CXCL10), and interferon signaling-related genes. In contrast, we discovered that STAT3 was a negative regulator of STAT1/cGAS-STING signaling-it suppressed senescence and inflammation. These data provide insights into how STAT1/STAT3 signaling coordinates senescence and inflammation through functional interactions with the cGAS/STING pathway.

Multilevel Regulation of Protein Kinase CδI Alternative Splicing by Lithium Chloride

Lithium chloride (LiCl) is commonly used in treatment of mood disorders; however, its usage leads to weight gain, which promotes metabolic disorders. Protein kinase C delta (PKCδ), a serine/threonine kinase, is alternatively spliced to PKCδI and PKCδII in 3T3-L1 cells. We previously demonstrated that PKCδI is the predominantly expressed isoform in 3T3-L1 preadipocytes. Here, we demonstrate that LiCl treatment decreases PKCδI levels, increases formation of lipid droplets, and increases oxidative stress. Hence, we investigated the molecular mechanisms underlying the regulation of PKCδI alternative splicing by LiCl. We previously demonstrated that the splice factor SFRS10 is essential for PKCδI splicing. Our results demonstrate that glycogen synthase kinase 3 beta (GSK3β) phosphorylates SFRS10, and SFRS10 is in a complex with long noncoding RNA NEAT1 to promote PKCδI splicing. Using PKCδ splicing minigene and RNA immunoprecipitation assays, our results demonstrate that upon LiCl treatment, NEAT1 levels are reduced, GSK3β activity is inhibited, and SFRS10 phosphorylation is decreased, which leads to decreased expression of PKCδI. Integration of the GSK3β signaling pathway with the ribonucleoprotein complex of long noncoding RNA (lncRNA) NEAT1 and SFRS10 enables fine-tuning of PKCδI expression during adipogenesis. Knowledge of the molecular pathways impacted by LiCl provides an understanding of the ascent of obesity as a comorbidity in disease management.

mesocarp Protects Preadipocytes against Ribosylated BSA-Induced Toxicity

OBJECTIVE

It was aimed at comparing the glycating capacities of glucose and ribose in bovine serum albumin (BSA) and anti-glycation activity of pomegranate mesocarp extract (PME). The protective mechanism of PME against ribosylated BSA (BSA_RIB)-induced toxicity was also investigated.

METHODS

BSA was incubated with glucose or ribose in the presence or absence of PME for 15 days. In preadipocytes pretreated with PME, cell viability, ROS production, lipid peroxidation and mitochondrial membrane potential were investigated following 1, 6, 12, 18 and 24 h exposure to BSA_RIB. Nuclear translocation of NFκB was assessed at 1 h and 24 h of BSA_RIB insult. Accumulation of oxidized proteins, activities of intrinsic antioxidant enzymes and IL-6 secretion were also determined after 24 h exposure to BSA_RIB.

RESULTS

Ribose was a harsher glycating agent as compared to glucose and PME showed strong anti-glycation activity by suppressing (P < 0.05) the increase in levels of fluorescent AGEs, Amadori products, protein carbonyl and advanced oxidation protein products (AOPP). In preadipocytes, BSA_RIB potentiated pro-apoptotic activity by inhibiting the nuclear translocation of NFκB. BSA_RIB induced a time dependent decrease in cell viability, which was significantly suppressed (P < 0.05) by PME. The extract also significantly reduced (P < 0.05) the time dependent increase in ROS level and associated lipid peroxidation as well as loss in mitochondrial membrane potential caused by BSA_RIB. PME also counteracted the BSA_RIB-induced accumulation of oxidized proteins, decrease in intrinsic antioxidant activity and IL-6 over-secretion.

CONCLUSIONS

PME showed anti-glycation activity and afforded protection against BSA_RIB-induced toxicity, oxidative stress and inflammation in preadipocytes.

Transcriptional control of chicken KLF7 promoter in preadipocytes

Krüppel-like factor 7 (KLF7) has been reported to inhibit adipogenesis and regulate the development of the nervous system. However, transcription regulation of KLF7 remains poorly understood. In the current study, a 2196-bp-long 5'-flanking sequence of chicken KLF7 (-2286 bp to -91 bp, upstream of the translation start site) was studied for promoter activity, and there was a remarkable promoter activity in this sequence (P<0.05). The 5'-truncated mutation analysis showed that a minimal promoter was on the sequence from -241 bp to -91 bp. In addition, GATA2 overexpression facilitated the promoter activity of pGL3-KLF7(-2286/-91), pGL3-KLF7(-1215/-91), pGL3-KLF7(-521/-91), and pGL3-KLF7(-241/-91), and GATA3 overexpression inhibited the promoter activity of pGL3-KLF7(-1845/-91), pGL3-KLF7(-1215/-91), pGL3-KLF7(-521/-91), and pGL3-KLF7(-241/-91) in chicken preadipocytes (P<0.05). Knockdown of GATA2 expression inhibited the promoter activity of pGL3-KLF7(-1215/-91) and pGL3-KLF7(-241/-91), and knockdown of GATA3 expression facilitated the promoter activity of pGL3-KLF7(-521/-91) and pGL3-KLF7(-241/-91) (P<0.05). Additionally, overexpression and knockdown analyses showed that GATA3 inhibited KLF7 mRNA expression (P<0.05), and both overexpression and knockdown of GATA2 resulted in the downregulation of KLF7 mRNA expression in chicken preadipocytes (P<0.05). Western blot analysis in chicken preadipocytes showed that GATA2 facilitated KLF7 expression and GATA3 inhibited KLF7 expression. Mutation analysis showed that the motif of 'GGATCTATCA' (-107 bp/-98 bp) might be a cis-regulation element, which is involved in the KLF7 expression regulation by GATA3 in chicken preadipocytes. These results provided some details of KLF7 transcription regulation in chicken adipose tissue.

Control of adipogenic commitment by a STAT3-VSTM2A axis

White adipose tissue (WAT) is a dynamic organ that plays crucial roles in controlling metabolic homeostasis. During development and periods of energy excess, adipose progenitors are recruited and differentiate into adipocytes to promote lipid storage capability. The identity of adipose progenitors and the signals that promote their recruitment are still incompletely characterized. We have recently identified V-set and transmembrane domain-containing protein 2A (VSTM2A) as a novel protein enriched in preadipocytes that amplifies adipogenic commitment. Despite the emerging role of VSTM2A in promoting adipogenesis, the molecular mechanisms regulating Vstm2a expression in preadipocytes are still unknown. To define the molecular mechanisms controlling Vstm2a expression, we have treated preadipocytes with an array of compounds capable of modulating established regulators of adipogenesis. Here, we report that Vstm2a expression is positively regulated by PI3K/mTOR and cAMP-dependent signaling pathways and repressed by the MAPK pathway and the glucocorticoid receptor. By integrating the impact of all the molecules tested, we identified signal transducer and activator of transcription 3 (STAT3) as a novel downstream transcription factor affecting Vstm2a expression. We show that activation of STAT3 increased Vstm2a expression, whereas its inhibition repressed this process. In mice, we found that STAT3 phosphorylation is elevated in the early phases of WAT development, an effect that strongly associates with Vstm2a expression. Our findings identify STAT3 as a key transcription factor regulating Vstm2a expression in preadipocytes.NEW & NOTEWORTHY cAMP-dependent and PI3K-mTOR signaling pathways promote the expression of Vstm2a. STAT3 is a key transcription factor that controls Vstm2a expression in preadipocytes. STAT3 is activated in the early phases of WAT development, an effect that strongly associates with Vstm2a expression.

miR-223-3p as a potential biomarker and player for adipose tissue dysfunction preceding type 2 diabetes onset

Circulating microRNAs (miRNAs) have been proposed as biomarkers for type 2 diabetes (T2D). Adipose tissue (AT), for which dysfunction is widely associated with T2D development, has been reported as a major source of circulating miRNAs. However, the role of dysfunctional AT in the altered pattern of circulating miRNAs associated with T2D onset remains unexplored. Herein, we investigated the relationship between T2D-associated circulating miRNAs and AT function, as well as the role of preadipocytes and adipocytes as secreting cells of candidate circulating miRNAs. Among the plasma miRNAs related to T2D onset in the CORonary Diet Intervention with Olive oil and cardiovascular PREVention (CORDIOPREV) cohort, baseline miR-223-3p levels (diminished in patients who next developed T2D [incident-T2D]) were significantly related to AT insulin resistance (IR). Baseline serum from incident-T2D participants induced inflammation and IR in 3T3-L1 adipocytes. We demonstrated that tumor necrosis factor (TNF)-α inhibited miR-223-3p secretion while enhancing miR-223-3p intracellular accumulation in 3T3-L1 (pre)adipocytes. Overexpression studies showed that an intracellular increase of miR-223-3p impaired glucose and lipid metabolism in these cells. Our findings provide mechanistic insights into the alteration of circulating miRNAs preceding T2D, unveiling both preadipocytes and adipocytes as miR-223-3p-secreting cells and suggesting that inflammation promotes miR-223-3p intracellular accumulation, which might contribute to (pre)adipocyte dysfunction and body metabolic dysregulation.

Effect of Neudesin Neurotrophic Factor on Differentiation of Bovine Preadipocytes and Myoblasts in a Co-Culture System

Simple Summary

Marbling beef refers to the red and white beef formed by depositing fat between muscle fibers, and “marbling” is an important factor affecting beef quality. Therefore, we established a co-culture system of adipocytes and myocytes to mimic the microenvironment of marbling beef in vivo. However, Neudesin neurotrophic factor (NENF) was not detected in the co-culture system, but was detected in both adipocytes and myoblasts cultured separately. Further studies revealed that NENF knockdown inhibits adipogenesis and promotes myogenesis in separately cultured preadipocytes and myoblasts. However, because the monoculture system does not include the interaction of bovine adipocytes and myoblasts in the formation of marbling beef, in this study we investigated the effect of recombinant protein NENF on the differentiation of adipocytes and myoblasts in the co-culture system. The addition of NENF inhibited the formation of lipid droplets in co-cultured adipocytes but had no significant effect on myotube formation. These results were different from, and even conflicted with, those in the monocultures, which suggested that regulation of NENF expression in the same cell type changed along with the cell microenvironment and the molecular mechanism of marbling beef formation cannot be fully revealed through studies on the monoculture system.

Abstract

In this study, we successfully established a co-culture system of bovine preadipocytes and myoblasts to explore the effect of exogenous addition of Neudesin neurotrophic factor (NENF) recombinant protein on the differentiation of adipocytes and myoblasts in co-culture. The optimal concentration of NENF recombinant protein was 100 pg/mL. NENF promoted the differentiation of bovine preadipocytes and inhibited the differentiation of bovine myoblasts when the cells were cultured separately. After adding NENF recombinant protein to the co-culture system, the accumulation of lipid droplets in bovine preadipocytes decreased, but the differentiation of bovine myoblasts did not change significantly. The results of real-time quantitative PCR (RT-qPCR) and Western blot showed that the expression levels of adipogenesis-related factors such as PPARγ, FABP4 and FASN were significantly down-regulated at the mRNA and protein levels in adipocytes, while myogenic marker genes such as MYOD1, MYOG and MYHC had no significant changes at the mRNA or protein levels in myoblasts. This differs from, and potentially conflicts with, the monoculture system, where NENF expression in each cell type changed with the cell microenvironment. Consequently, the molecular mechanism of marbling beef formation cannot be fully revealed using monocultures of adipocytes or myocytes.

Elevated miR-10a-5p facilitates cell cycle and restrains adipogenic differentiation via targeting Map2k6 and Fasn, respectively

miRNAs are a small class of noncoding RNAs that perform biological functions by regulating the stability or translation of target genes in various biological processes. This study illustrated the role of miR-10a-5p, which is relatively enriched in adipose tissues, using primary mouse preadipocytes as model. With elevated miR-10a-5p expression, the proliferative ability of mouse preadipocytes was significantly enhanced, indicated by increased EdU+ cells and G1/S transition, accompanied by upregulated Cyclin B, Cyclin D and PCNA and downregulated p21 and p27. Meanwhile, the adipogenic differentiation was significantly attenuated by elevated miR-10a-5p, supported by Oil Red O staining and suppressed PPARγ and aP2 expression. Furthermore, Map2k6 and Fasn were predicted to be the target genes of miR-10a-5p in silico, and dual luciferase reporter assay confirmed the direct targeting effects. Western blot analysis results showed that miR-10a-5p specially reduced Map2k6 expression at the proliferative stage without affecting Fasn expression, while significantly restrained Fasn expression with unchanged Map2k6 expression during adipogenic differentiation. Taken together, these results revealed a potential role of miR-10a-5p in adipogenesis and in the treatment of obesity.

A Representative GIIA Phospholipase A2 Activates Preadipocytes to Produce Inflammatory Mediators Implicated in Obesity Development

Adipose tissue secretes proinflammatory mediators which promote systemic and adipose tissue inflammation seen in obesity. Group IIA (GIIA)-secreted phospholipase A₂ (sPLA₂) enzymes are found to be elevated in plasma and adipose tissue from obese patients and are active during inflammation, generating proinflammatory mediators, including prostaglandin E₂ (PGE₂). PGE₂ exerts anti-lipolytic actions and increases triacylglycerol levels in adipose tissue. However, the inflammatory actions of GIIA sPLA₂s in adipose tissue cells and mechanisms leading to increased PGE₂ levels in these cells are unclear. This study investigates the ability of a representative GIIA sPLA₂, MT-III, to activate proinflammatory responses in preadipocytes, focusing on the biosynthesis of prostaglandins, adipocytokines and mechanisms involved in these effects. Our results showed that MT-III induced biosynthesis of PGE₂, PGI₂, MCP-1, IL-6 and gene expression of leptin and adiponectin in preadipocytes. The MT-III-induced PGE₂ biosynthesis was dependent on cytosolic PLA₂ (cPLA₂)-α, cyclooxygenases (COX)-1 and COX-2 pathways and regulated by a positive loop via the EP₄ receptor. Moreover, MT-III upregulated COX-2 and microsomal prostaglandin synthase (mPGES)-1 protein expression. MCP-1 biosynthesis induced by MT-III was dependent on the EP4 receptor, while IL-6 biosynthesis was dependent on EP3 receptor engagement by PGE₂. These data highlight preadipocytes as targets for GIIA sPLA₂s and provide insight into the roles played by this group of sPLA₂s in obesity.

Modeling Adipogenesis: Current and Future Perspective

Adipose tissue is contemplated as a dynamic organ that plays key roles in the human body. Adipogenesis is the process by which adipocytes develop from adipose-derived stem cells to form the adipose tissue. Adipose-derived stem cells’ differentiation serves well beyond the simple goal of producing new adipocytes. Indeed, with the current immense biotechnological advances, the most critical role of adipose-derived stem cells remains their tremendous potential in the field of regenerative medicine. This review focuses on examining the physiological importance of adipogenesis, the current approaches that are employed to model this tightly controlled phenomenon, and the crucial role of adipogenesis in elucidating the pathophysiology and potential treatment modalities of human diseases. The future of adipogenesis is centered around its crucial role in regenerative and personalized medicine.

Maternal food restriction-induced intrauterine growth restriction in a rat model leads to sex-specific adipogenic programming

Intrauterine growth restriction (IUGR) leads to offspring obesity. In a maternal food restriction (MFR) during pregnancy-related IUGR rat model, bone marrow stem cells showed enhanced adipogenic programming; however, the effect of IUGR on white adipose tissue (WAT) progenitors is unknown. Here, by mRNA and functional profiling, we determined sex-specific adipogenic programming of WAT progenitors isolated from pups on the postnatal day (PND) 1 and 21. On PND1, PPARγ and Pref-1 expression was significantly downregulated in preadipocytes of both MFR males and females; however, at PND21, preadipocytes of MFR males showed upregulation in these genes. Even following adipogenic induction, both male and female MFR adipocytes exhibited lower PPARγ, ADRP, and adiponectin levels at PND1; however, at PND21 MFR male adipocytes showed an upward trend in the expression of these genes. An adipogenesis-specific RT-PCR array showed that male MFR adipocytes were programmed to exhibit stronger adipogenic propensity than females. Last, serum sex hormone and adipocyte estrogen/testosterone receptor expression profiles provide preliminary insights into the possible mechanism underlying sex-specific adipogenic programming in the IUGR offspring. In summary, IUGR programs WAT preadipocytes to greater adipogenic potential in males. Although the altered adipogenic programming following MFR was detectable at PND1, the changes were more pronounced at PND21, suggesting a potential role of postnatal nutrition in facilitating the sex-specific adipogenic programming in the IUGR offspring.

Genetic and Pharmacological Inhibition of PAPP-A Protects Against Visceral Obesity in Mice

Pathogenicity of visceral adipose tissue (VAT) has been linked to the metabolic stress of enlarging mature adipocytes and a limited ability to recruit new adipocytes. One of the major distinguishing features of VAT preadipocytes is the high expression of the zinc metalloprotease, pregnancy-associated plasma protein-A (PAPP-A), when compared to subcutaneous adipose tissue (SAT). In this study we used 2 different approaches to investigate the effect of PAPP-A inhibition on different fat depots in mice on a high-fat diet (HFD) for 15 weeks. Conditional knockdown of PAPP-A gene expression in female adult mice resulted in significant decreases of 30% to 40% in adipocyte size in VAT (mesenteric and pericardial depots) compared to control mice. There was no effect on SAT (inguinal) or intra-abdominal perigonadal fat. Liver lipid was also significantly decreased without any effect on heart and skeletal muscle lipid. We found similar effects when using a pharmacological approach. Weekly injections of a specific immunoneutralizing monoclonal antibody (mAb-PA 1/41) or isotype control were given to male and female wild-type mice on HFD for 15 weeks. Adipocyte size was significantly decreased (30%-50%) only in VAT with mAb-PA 1/41 treatment. In this model, cell number was significantly increased in mesenteric fat in mice treated with mAb-PA 1/41, suggesting hyperplasia along with reduced hypertrophy in this VAT depot. Gene expression data indicated a significant decrease in F4/80 (macrophage marker) and interleukin-6 (proinflammatory cytokine) and a significant increase in adiponectin (anti-inflammatory adipokine with beneficial metabolic effects) in mesenteric fat compared to inguinal fat in mice treated with mAb-PA 1/41. Furthermore, there was significantly decreased liver lipid content with mAb-PA 1/41 treatment. Thus, using 2 different models systems we provide proof of principle that PAPP-A inhibition is a potential therapeutic target to prevent visceral obesity and its metabolic sequelae, such as fatty liver.

Research Note: All-trans retinoic acids induce adipogenic differentiation of chicken embryonic fibroblasts and preadipocytes

Adipocytes store excess energy in the form of lipids, whereas fat accretion contributes to feed efficiency, meat quality, and female reproduction in poultry. As a metabolite of vitamin A, all-trans retinoic acid (atRA) has been shown to have influence over metabolic functions such as lipid and energy homeostasis, as well as adipogenesis. Although atRA has been known to function as a regulating factor in mammalian adipogenesis, the effects of atRA on adipogenesis has not been studied in chickens. In this study, chicken preadipocytes isolated from leg fat tissues at embryonic day (E) 14 and chicken embryonic fibroblasts (CEF) harvested at E5 were cultured. The preadipocytes and CEF in culture with 10% chicken serum were treated with various concentrations (0 μmol, 100 μmol, or 150 μmol) of supplemented atRA for 48 h. In these cells, cytoplasmic lipid droplet accumulation and mRNA expression for adipogenic genes were analyzed by Oil-Red-O staining and quantitative real-time PCR, respectively. Analysis of the relative amount of Oil-Red-O staining (lipid accumulation) revealed that all 3 variables increased in a dose-dependent manner, in response to increasing atRA supplementation. Genes involved in adipocyte differentiation, fatty acid transport, and triacylglycerol synthesis in both E14 preadipocytes and E5 CEF were upregulated by supplementation of atRA. These data demonstrated that atRA alone promoted adipogenesis of embryonic preadipocytes and fibroblasts in vitro, suggesting that atRA has an influential role in multiple stages of adipogenesis in chicken embryos.

NOTCH Receptors and DLK Proteins Enhance Brown Adipogenesis in Mesenchymal C3H10T1/2 Cells

The NOTCH family of receptors and ligands is involved in numerous cell differentiation processes, including adipogenesis. We recently showed that overexpression of each of the four NOTCH receptors in 3T3-L1 preadipocytes enhances adipogenesis and modulates the acquisition of the mature adipocyte phenotype. We also revealed that DLK proteins modulate the adipogenesis of 3T3-L1 preadipocytes and mesenchymal C3H10T1/2 cells in an opposite way, despite their function as non-canonical inhibitory ligands of NOTCH receptors. In this work, we used multipotent C3H10T1/2 cells as an adipogenic model. We used standard adipogenic procedures and analyzed different parameters by using quantitative-polymerase chain reaction (qPCR), quantitative reverse transcription-polymerase chain reaction (qRT-PCR), luciferase, Western blot, and metabolic assays. We revealed that C3H10T1/2 multipotent cells show higher levels of NOTCH receptors expression and activity and lower Dlk gene expression levels than 3T3-L1 preadipocytes. We found that the overexpression of NOTCH receptors enhanced C3H10T1/2 adipogenesis levels, and the overexpression of NOTCH receptors and DLK (DELTA-like homolog) proteins modulated the conversion of cells towards a brown-like adipocyte phenotype. These and our prior results with 3T3-L1 preadipocytes strengthen the idea that, depending on the cellular context, a precise and highly regulated level of global NOTCH signaling is necessary to allow adipogenesis and determine the mature adipocyte phenotype.

[Melatonin Induces Apoptotic Cell Death in 3T3-L1 Preadipocytes]

Obesity is a major disease that causes significant complications. Inhibition of preadipocyte proliferation has the potential to prevent obesity and metabolic diseases. Melatonin is a pineal gland hormone that has various effects on cells and tissues. In this research, we investigated whether melatonin induces apoptosis in 3T3-L1 preadipocytes. 3T3-L1 preadipocytes were cultured until confluence and then treated with 0, 10, 100, and 1000 μM melatonin for 1, 3, and 5 days. A cell viability assay kit was used for determining cell viability. Cell death marker proteins were assessed by Western blot analysis using GAPDH for control. Apoptotic morphological changes with nuclei fragmentation were observed using DAPI staining. Melatonin treatment decreased the phosphorylated extracellular signal-regulated kinases (p-ERK) activation while increasing the activation of caspase-3, 8, and 9. Furthermore, melatonin not only increased Bcl-2-associated X protein (Bax) but decreased B-cell lymphoma 2 (Bcl-2) expression as dose increases from 0 to 1000 μM. The melatonin treatment also suppressed the growth of preadipocytes with increasing concentration. These effects were attenuated by luzindole, a melatonin receptor antagonist and U0126, an inhibitor of p-ERK activation. In conclusion, melatonin can induce apoptosis of 3T3-L1 preadipocytes via p-ERK decrease.

Anthocyanin-Enriched Riceberry Rice Extract Inhibits Cell Proliferation and Adipogenesis in 3T3-L1 Preadipocytes by Downregulating Adipogenic Transcription Factors and Their Targeting Genes

Riceberry rice (Oryza sativa L.) is a new pigmented variety of rice from Thailand. Despite its high anthocyanin content, its effect on adipogenesis and adipocyte function remains unexplored. We investigated whether Riceberry rice extract (RBE) impacted cell proliferation by examining viability and cell cycle, using preadipocyte 3T3-L1 cells. To test RBE's effect on adipocyte formation, cells were cultured in adipogenic medium supplemented with extract and adipocyte number and triglyceride levels were quantified. Furthermore, Akt1 phosphorylation along with RT-qPCR and intracellular calcium imaging were performed to obtain an insight into its mechanism of action. The effect of RBE on adipocyte function was investigated using glucose uptake and lipolysis assays. Treatment of cells with RBE decreased preadipocyte number without cytotoxicity despite inducing cell cycle arrest (p < 0.05). During adipogenic differentiation, RBE supplementation reduced adipocyte number and triglyceride accumulation by downregulating transcription factors (e.g., PPARγ, C/EBPα, and C/EBPβ) and their target genes (p < 0.05). The Akt1 phosphorylation was decreased by RBE but insignificance, however, the extract failed to increase intracellular calcium signals. Finally, the treatment of adipocytes with RBE reduced glucose uptake by downregulating Glut4 mRNA expression and enhanced isoproterenol-induced lipolysis (p < 0.05). These findings suggest that RBE could potentially be used in the treatment of obesity by inhibiting adipocyte formation and proliferation.

Acute Aerobic Exercise Remodels the Adipose Tissue Progenitor Cell Phenotype in Obese Adults

Adipose tissue pathology in obese patients often features impaired adipogenesis, angiogenesis, and chronic low-grade inflammation, all of which are regulated in large part by adipose tissue stromal vascular cells [SVC; i.e., non-adipocyte cells within adipose tissue including preadipocytes, endothelial cells (ECs), and immune cells]. Exercise is known to increase subcutaneous adipose tissue lipolysis, but the impact of exercise on SVCs in adipose tissue has not been explored. The purpose of this study was to assess the effects of a session of exercise on preadipocyte, EC, macrophage, and T cell content in human subcutaneous adipose tissue. We collected abdominal subcutaneous adipose tissue samples from 10 obese adults (BMI 33 ± 3 kg/m², body fat 41 ± 7%) 12 h after a 60 min acute session of endurance exercise (80 ± 3%HR_peak) vs. no acute exercise session. SVCs were isolated by collagenase digestion and stained for flow cytometry. We found that acute exercise reduced preadipocyte content (38 ± 7 vs. 30 ± 13%SVC; p = 0.04). The reduction was driven by a decrease in CD34^hi preadipocytes (18 ± 5 vs. 13 ± 6%SVC; p = 0.002), a subset of preadipocytes that generates high lipolytic rate adipocytes ex vivo. Acute exercise did not alter EC content. Acute exercise also did not change total immune cell, macrophage, or T cell content, and future work should assess the effects of exercise on subpopulations of these cells. We conclude that exercise may rapidly regulate the subcutaneous adipose tissue preadipocyte pool in ways that may help attenuate the high lipolytic rates that are commonly found in obesity.

How Does Ginsenoside Rh2 Mitigate Adipogenesis in Cultured Cells and Obese Mice?

Ginsenoside Rh2, an intermediate metabolite of ginseng, but not naturally occurring, has recently drawn attention because of its anticancer effect. However, it is not clear if and how Rh2 inhibits preadipocytes differentiation. In the present study, we hypothesized that ginsenoside Rh2 attenuates adipogenesis through regulating the peroxisome proliferator-activated receptor gamma (PPAR-γ) pathway both in cells and obese mice. Different concentrations of Rh2 were applied both in 3T3-L1 cells and human primary preadipocytes to determine if Rh2 inhibits cell differentiation. Dietary Rh2 was administered to obese mice to determine if Rh2 prevents obesity in vivo. The mRNA and protein expression of PPAR-γ pathway molecules in cells and tissues were measured by real-time polymerase chain reaction (RT-PCR) and Western blot, respectively. Our results show that Rh2 dose-dependently (30-60 μM) inhibited cell differentiation in 3T3-L1 cells (44.5% ± 7.8% of control at 60 μM). This inhibitory effect is accompanied by the attenuation of the protein and/or mRNA expression of adipogenic markers including PPAR-γ and CCAAT/enhancer binding protein alpha, fatty acid synthase, fatty acid binding protein 4, and perilipin significantly (p < 0.05). Moreover, Rh2 significantly (p < 0.05) inhibited differentiation in human primary preadipocytes at much lower concentrations (5-15 μM). Furthermore, dietary intake of Rh2 (0.1 g Rh2/kg diet, w/w for eight weeks) significantly (p < 0.05) reduced protein PPAR-γ expression in liver and hepatic glutathione reductase and lowered fasting blood glucose. These results suggest that ginsenoside Rh2 dose-dependently inhibits adipogenesis through down-regulating the PPAR-γ pathway, and Rh2 may be a potential agent in preventing obesity in vivo.