Adipogenic Process Research Articles

ACSL1 positively regulates adipogenic differentiation

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

Investigation of adipocyte differentiation based on proteomics and intact N-glycopeptide modificationomics

ObjectiveTo investigate the role of N-glycosylation modification of proteins in adipocyte differentiation during the adipogenic process. MethodsSVF cells and adipocytes were analyzed for proteomics and intact N-glycopeptide modificationomics.Differential expression of proteins, glycoforms, and sites between the two groups was screened and subjected to Gene Ontology (GO) functional enrichment analysis, KEGG pathway enrichment analysis, and protein-protein interaction (PPI) network analysis. The top 20 most significantly differentially expressed adipogenic differentiation-related proteins were identified, and the most pronouncedly altered proteins were analyzed for glycoforms, glycan chains, and sites. ResultsProteomics analysis identified 39,392 peptides and 5208 proteins, while intact N-glycopeptide modification profiling identified 3293 intact glycopeptides, 426 proteins, and 161 glycan chains. Proteomics identified 2510 differentially expressed proteins, with CD36 (Cluster of Differentiation 36, CD36) significantly upregulated. In adipocytes, CD36 had 4 N-glycosylation sites: N79, N220, N320, N417, with N320 being a newly identified site. GO enrichment results indicated that CD36 is associated with fatty acid oxidation, lipid oxidation, and fatty acid uptake into cells. ConclusionMultiple proteins undergo N-glycosylation modification during adipocyte differentiation, with CD36, a fatty acid translocase, being significantly expressed in adipocytes. This suggests that N-glycosylation modification of CD36 may play a crucial role in adipocyte differentiation, providing a foundation for further investigation into the function of CD36 N-glycosylation in adipocyte differentiation.

Effect of Epigenetic Inhibitors on Adipogenesis in Human Periodontal Ligament Stem Cells

Histone H3 lysine 9 acetylation is a crucial epigenetic mark in mesenchymal stem cell differentiation processes like adipogenesis. This study aimed to evaluate the effect of epigenetic inhibitors on adipogenesis in human periodontal ligament stem cells, using histone deacetylase inhibitors such as valproic acid and trichostatin A. The cells were treated independently with 8 mM valproic acid and 100 nM trichostatin A for 72 hours to inhibit class I histone deacetylases. Subsequently, the cells underwent adipogenic induction for 28 days. Morphology and intracellular lipid deposition were analyzed using Oil-Red oil staining. Protein extracts were prepared on days 0 and 28 to analyze histone H3 lysine 9 acetylation levels via Western blot. Our results demonstrated that cells treated with either VPA or TSA showed, on average, a 1.275-fold increase in lipid deposition during the adipogenic process, with no significant differences between the treatments compared to the control group. Further, by day 28, histone H3 lysine 9 acetylation levels were 1.43 times higher in cells treated with valproic acid and 2.52 times higher in those treated with trichostatin A.These findings suggest that the inhibitors could have differential effects on chromatin remodeling in different regions by increasing acetylation, contributing indistinctly to lipid deposition due to the greater expression of genes associated with the adipogenic phenotype.

Ascochlorin Attenuates the Early Stage of Adipogenesis via the Wnt/β-Catenin Pathway and Inhibits High-Fat-Diet-Induced Obesity in Mice.

This study investigated the effects of ascochlorin (ASC), a natural compound derived from the fungus Ascochyta viciae, on adipogenesis and obesity. We determined the effects of ASC on 3T3-L1 preadipocytes and whether it ameliorated to mitigate high-fat diet (HFD)-induced obesity in C57BL/6J mice. We found that ASC significantly inhibited the differentiation of preadipocytes by modulating the Wnt/β-catenin signaling pathway, a key regulator of adipogenic processes. Treatment with ASC not only reduced the mRNA and protein expression of key adipogenic transcription factors such as C/EBPα and PPARγ, but also reduced lipid accumulation both in vitro and in vivo. In addition, treatment HFD-fed mice with ASC significantly reduced their weight gain and adiposity vs. control mice. These results suggest that ASC has considerable potential as a therapeutic agent for obesity, owing to its dual action of inhibiting adipocyte differentiation and reducing lipid accumulation. Thus, ASC represents a promising candidate as a natural anti-obesity agent.

Epigenetic and transcriptional control of adipocyte function by centenarian-associated SIRT6 N308K/A313S mutant

BackgroundObesity is a major health burden. Preadipocytes proliferate and differentiate in mature adipocytes in the adipogenic process, which could be a potential therapeutic approach for obesity. Deficiency of SIRT6, a stress-responsive protein deacetylase and mono-ADP ribosyltransferase enzyme, blocks adipogenesis. Mutants of SIRT6 (N308K/A313S) were recently linked to the in the long lifespan Ashkenazi Jews. In this study, we aimed to clarify how these new centenarian-associated SIRT6 genetic variants affect adipogenesis at the transcriptional and epigenetic level.MethodsWe analyzed the role of SIRT6 wild-type (WT) or SIRT6 centenarian-associated mutant (N308K/A313S) overexpression in adipogenesis, by creating stably transduced preadipocyte cell lines using lentivirus on the 3T3-L1 model. Histone post-translational modifications (PTM: acetylation, methylation) and transcriptomic changes were analyzed by mass spectrometry (LC–MS/MS) and RNA-Seq, respectively, in 3T3-L1 adipocytes. In addition, the adipogenic process and related signaling pathways were investigated by bioinformatics and biochemical approaches.ResultsOverexpression of centenarian-associated SIRT6 mutant increased adipogenic differentiation to a similar extent compared to the WT form. However, it triggered distinct histone PTM profiles in mature adipocytes, with significantly higher acetylation levels, and activated divergent transcriptional programs, including those dependent on signaling related to the sympathetic innervation and to PI3K pathway. 3T3-L1 mature adipocytes overexpressing SIRT6 N308K/A313S displayed increased insulin sensitivity in a neuropeptide Y (NPY)-dependent manner.ConclusionsSIRT6 N308K/A313S overexpression in mature adipocytes ameliorated glucose sensitivity and impacted sympathetic innervation signaling. These findings highlight the importance of targeting SIRT6 enzymatic activities to regulate the co-morbidities associated with obesity.

Effect of Arthrospira maxima Phycobiliproteins, Rosiglitazone, and 17β-Estradiol on Lipogenic and Inflammatory Gene Expression during 3T3-L1 Preadipocyte Cell Differentiation.

The study evaluated the effects of Arthrospira maxima phycobiliproteins (PBPs), rosiglitazone (RSG), and 17β-estradiol (E) on the differentiation process of 3T3-L1 cells and on their regulation of lipogenic and inflammatory gene expression at different stages of the process. The results showed that phycobiliproteins promoted cell proliferation after 24 h of treatment. Furthermore, for all three treatments, the regulation of the highest number of markers occurred on days 6 and 12 of differentiation, regardless of when the treatment was applied. Phycobiliproteins reduced lipid droplet accumulation on days 3, 6, 10, and 13 of the adipogenic process, while rosiglitazone showed no differences compared to the control. On day 6, both phycobiliproteins and rosiglitazone positively regulated Acc1 mRNA. Meanwhile, all three treatments negatively regulated Pparγ and C/ebpα. Phycobiliproteins and estradiol also negatively regulated Ucp1 and Glut4 mRNAs. Rosiglitazone and estradiol, on the other hand, negatively regulated Ppara and Il-6 mRNAs. By day 12, phycobiliproteins and rosiglitazone upregulated Pparγ mRNA and negatively regulated Tnfα and Il-1β. Additionally, phycobiliproteins and estradiol positively regulated Il-6 and negatively regulated Ppara, Ucp2, Acc1, and Glut4. Rosiglitazone and estradiol upregulate C/ebpα and Ucp1 mRNAs. The regulation exerted by phycobiliproteins on the mRNA expression of the studied markers was dependent on the phase of cell differentiation. The results of this study highlight that phycobiliproteins have an anti-adipogenic and anti-inflammatory effect by reducing the expression of adipogenic, lipogenic, and inflammatory genes in 3T3-L1 cells at different stages of the differentiation process.

Adenovirus 36 seropositivity is related to the expression of anti-adipogenic lncRNAs GAS5 and MEG3 in adipose tissue obtained from subjects with obesity.

Human Adenovirus D-36 (HAdV-D36) promotes adipogenesis in cellular and animal models and may contribute to the development of human obesity. Induction of PPARγ by HAdV-D36 seems to have a central role in the maintenance of adipogenic status. There is limited information about epigenetic mechanisms contributing to this process in human adipose tissue. This study evaluated the expression of lncRNAs (ADINR, GAS5 and MEG3) and miRNAs (miR-18a and miR-140) involved in the adipogenic process in visceral adipose tissue (VAT) of subjects with obesity with previous HAdV-D36 infection (seropositive) and unexposed (seronegative) subjects with obesity. Individuals with obesity were grouped according to the presence of antibodies against HAdV-D36 (Seropositive: HAdV-D36[+], n = 29; and Seronegative: HAdV-D36[-], n = 28). Additionally, a group of individuals without obesity (n = 17) was selected as a control group. The HAdV-D36 serology was carried out by ELISA. Biopsies of VAT were obtained during an elective and clinically indicated surgery (bariatric or cholecystectomy). RNA extraction from VAT was performed and the expression of PPARG and non-coding RNAs was evaluated by qPCR. HAdV-D36[+] individuals had lower expression of anti-adipogenic lncRNAs GAS5 (p = 0.016) and MEG3 (p = 0.035) compared with HAdV-D36[-] subjects with obesity. HAdV-D36[+] subjects also presented increased expression of the adipogenic miRNA miR-18a (p = 0.042), which has been reported to be modulated by GAS5 through a RNA sponging mechanism during adipogenic differentiation. Additionally, an inverse correlation of GAS5 with PPARG expression was observed (r = -0.917, p = 0.01). Our results suggest that HAdV-D36 is related to non-coding RNAs implicated in adipogenesis, representing a potential mechanism by which previous HAdV-D36 infection could be associated with the long-term maintenance of adipogenic status, probably through the GAS5/miR-18a axis.

Dysregulation of adipogenesis and disrupted lipid metabolism by the antidepressants citalopram and sertraline

Selective Serotonin Reuptake Inhibitors (SSRIs) are widely used medications for the treatment of major depressive disorder. However, long-term SSRI use has been associated with weight gain and altered lipid profiles. These findings suggest that SSRIs may have negative effects on metabolism. Exposure to certain chemicals called ‘obesogens’ is known to promote lipid accumulation and obesity by modulating adipogenesis. Here, we investigated whether citalopram (CIT) and sertraline (SER) interfere with the process of adipogenesis, using human mesenchymal stem cells (MSCs) in a 2D and a 3D model. Assessment of intracellular lipid accumulation by fluorescence staining was used as a measure for enhanced adipogenesis. To explore possible mechanisms behind SSRIs' effects, receptor mediated activity was studied using responsive cell lines for various nuclear receptors. Furthermore, RNA sequencing was performed in the 3D model, followed by differential gene expression and pathway analysis. A dose dependent increase in lipid accumulation was observed in both models with CIT and SER. For the 3D model, the effect was seen in a range close to reported steady-state plasma concentrations (0.065–0.65 μM for SER and 0.12–0.92 μM for CIT). Pathway analysis revealed unexpected results of downregulation in adipogenesis-related pathways and upregulation in phospholipids and lysosomal pathways. This was confirmed by an observed increase in lysosomes in the 2D model. Our findings suggest lysosomal dysfunction and disrupted lipid metabolism in mature adipocytes, leading to excessive phospholipid synthesis. Moreover, important adipogenic processes are inhibited, potentially leading to dysfunctional adipocytes, which might have implications in the maintenance of a healthy metabolic balance.

The Role of Zinc Finger Proteins in the Fate Determination of Mesenchymal Stem Cells during Osteogenic and Adipogenic Differentiation

Zinc finger proteins (ZFPs) constitute a crucial group of transcription factors widely present in various organisms. They act as transcription factors, nucleases, and RNA-binding proteins, playing significant roles in cell differentiation, growth, and development. With extensive research on ZFPs, their roles in the determination of mesenchymal stem cells (MSCs) fate during osteogenic and adipogenic differentiation processes have become increasingly clear. ZFP521, for instance, is identified as an inhibitor of the Wnt signaling pathway and RUNX2's transcriptional activity, effectively suppressing osteogenic differentiation. Moreover, ZFP217 contributes to the inhibition of adipogenic differentiation by reducing the M6A level of the cell cycle regulator cyclin D1 (CCND1). In addition, other ZFPs can also influence the fate of mesenchymal stem cells (MSCs) during osteogenic and adipogenic differentiation through various signaling pathways, transcription factors, and epigenetic controls, participating in the subsequent differentiation and maturation of precursor cells. Given the prevalent occurrence of osteoporosis, obesity, and related metabolic disorders, a comprehensive understanding of the regulatory mechanisms balancing bone and fat metabolism is essential, with a particular focus on the fate determination of MSCs in osteogenic and adipogenic differentiation. In this review, we provide a detailed summary of how zinc finger proteins influence the osteogenic and adipogenic differentiation of MSCs through different signaling pathways, transcription factors, and epigenetic mechanisms. Additionally, we outline the regulatory mechanisms of ZFPs in controlling osteogenic and adipogenic differentiation based on various stages of MSC differentiation.

Wnt10b knockdown regulates the relative balance of adipose tissue-resident T cells and inhibits white fat deposition.

Wnt10b is one of critical Wnt family members that being involved in networks controlling stemness, pluripotency and cell fate decisions. However, its role in adipose-resident T lymphocytes and further in fat metabolism yet remains largely unknown. In the present study, we demonstrated a distinctive effect for Wnt10b on the relative balance of T lymphocytes in adipose tissue by using a Wnt10b knockdown mouse model. Wnt10b knockdown led to a reduction of adipose-resident CD4+ T cells and an elevation of Foxp3+/CD4+ Treg cells. Wnt10b-knockdown mice fed with standard diet showed less white fat deposition owing to the suppressed adipogenic process. Moreover, under high fat diet conditions, Wnt10b knockdown resulted in an alleviated obesity symptoms, as well as an improvement of glucose homeostasis and hepatic steatosis. Collectively, we reveal an unexpected and novel function for Wnt10b in mediating the frequency of adipose-resident T cell subsets, that when knockdown skewing toward a Treg-dominated phenotype and further improving fat metabolism.

Emodin suppresses adipogenesis of bone marrow derived mesenchymal stem cells from aplastic anemia via increasing TRIB3 expression

BackgroundIncreasing evidence indicate that enhanced adipogenic differentiation of bone marrow mesenchymal stem cells (BM-MSCs) could contribute to the adiposity alteration in marrow microenvironment of aplastic anemia (AA). Identifying small molecule drugs with role in inhibiting adipogenesis of BM-MSCs may represent a novel direction in AA therapy by improving BM-MSCs mediated marrow microenvironment. MethodsFor the purpose, we isolated AA BM-MSCs through whole bone marrow cell culture, evaluated a series of small molecule drugs using the in vitro adipogenic differentiation model of BM-MSCs, and finally focused on emodin, a natural anthraquinone derivative. Subsequently, we systematically investigated the molecular mechanism of emodin in attenuating adipogenic process by means of microarray profiling, bioinformatics analysis and lentivirus-mediated functional studies and rescue assay. ResultsWe found that emodin presented significantly suppressive effect on the in vitro adipogenic differentiation of AA BM-MSCs. Further mechanistic investigation revealed that emodin could increase the expression of Tribbles homolog 3 (TRIB3) which exhibited remarkably decreased expression in AA BM-MSCs compared with the normal counterparts and was subsequently demonstrated as a negative regulator in adipogenesis of AA BM-MSCs. Besides, TRIB3 depletion alleviated the suppressive effect of emodin on the adipogenic differentiation of AA BM-MSCs. ConclusionOur findings propose that emodin mediated TRIB3 up-regulation alleviates the adipogenic capacity of AA BM-MSCs, and emodin could serve as a potential therapeutic regimen for AA therapy.

Dermal white adipose tissue development and metabolism: The role of transcription factor Foxn1.

Intradermal adipocytes form dermal white adipose tissue (dWAT), a unique fat depot localized in the lower layer of the dermis. However, recognition of molecular factors regulating dWAT development, homeostasis, and bioactivity is limited. Using Foxn1-/- and Foxn1+/+ mice, we demonstrated that epidermally expressed Foxn1 regulates dWAT development and defines the adipogenic capacity of dermal fibroblasts. In intact and post-wounded skin, Foxn1 contributes to the initial stimulation of dWAT adipogenesis and participates in the modulation of lipid metabolism processes. Furthermore, Foxn1 activity strengthens adipogenic processes through Bmp2 and Igf2 signaling and regulates lipid metabolism in differentiated dermal fibroblasts. The results reveal the contribution of Foxn1 to dWAT metabolism, thus identifying possible targets for modulation and regulation of dWAT in physiological and pathological processes in the skin.

Transcriptome profiling of differentiating adipose-derived stem cells across species reveals new genes regulating adipogenesis

Adipose-derived stem cells (ADSCs) that are enriched in adipose tissue with multilineage differentiation potential have become an important tool in therapeutic research and tissue engineering. Certain breeds of sheep exhibit a unique fat tail trait such that tail tissue accounts for approximately 10 % of body weight and can provide an excellent source of ADSCs. Here, we describe isolation of primary ADSCs from ovine embryonic fat tail tissues that displayed high self-renewal capacity, multilineage differentiation and excellent adipogenic ability. Through transcriptome analysis covering ADSCs differentiating into adipocytes, 37 transcription factors were involved in early transcriptional events that initiate a regulatory cascade of adipogenesis; the entire adipogenic activity consists of a reduction in proliferation ability and upregulation of genes related to lipid generation and energy metabolism, as well as several genes associated with myogenesis. Furthermore, Comparative transcriptome analysis across species (sheep, human, and mouse) revealed enhanced basal metabolic ability in differentiating ovine ADSCs, which may relate to the excellent adipogenic capability of these cells. We also identified a small evolutionarily conserved gene set, consisting of 21 and 22 genes exhibiting increased and decreased expression, respectively. Almost half (20) of these genes have not previously been reported to regulate adipogenesis in mammals. In this study, we identified important regulators that trigger ovine adipocyte differentiation, main biological pathways involved in adipogenesis as well as the evolutionarily conserved genes governing adipogenic process across species. Our study provides a novel excellent biomaterial and novel genes regulating adipogenesis for cellular transplantation therapy and investigations of fat metabolism.

Regulation of mitotic clonal expansion and thermogenic pathway are involved in the antiadipogenic effects of cyanidin-3-O-glucoside.

Introduction: Obesity is a metabolic disease with an increase both in cell size (hypertrophy) and in cell number (hyperplasia) following differentiation of new adipocytes. Adipogenesis is a well-orchestrated program in which mitotic clonal expansion (MCE) occurs in the early step followed by the late terminal differentiation one. Methods: Aim of the study was to evaluate the in vitro effects of cyanidin-3-O-glucoside (C3G), an anthocyanin present in many fruits and vegetables, in the early or late phase of 3T3-L1 preadipocytes differentiation. Results: C3G exposure in the early phase of adipogenesis process induced a more marked reduction of CCAAT/enhancer-binding protein-β (C/EBPβ), peroxisome proliferator-activated receptor γ (PPAR-ɣ) and fatty acid synthase (Fasn) expression than late phase exposure and these effects were associated to a reduced MCE with cell cycle arrest at G0/G1 phase via p21 expression. Furthermore, C3G exposure during the early phase activated AMP-activated protein kinase (AMPK) pathway better than in the late phase promoting the enhancement of beige-like adipocytes. In fact, C3G induced thermogenic biomarkers uncoupling protein-1 (Ucp1) and peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (Pgc1) and these effects were more evident during early phase exposure. Conclusion: Our data demonstrate that C3G reduces the terminal adipogenic process affecting the early phase of differentiation and inducing a thermogenic program.

PKN1 Kinase: A Key Player in Adipocyte Differentiation and Glucose Metabolism.

Adipocyte dysfunction is the driver of obesity and correlates with insulin resistance and the onset of type 2 diabetes. Protein kinase N1 (PKN1) is a serine/threonine kinase that has been shown to contribute to Glut4 translocation to the membrane and glucose transport. Here, we evaluated the role of PKN1 in glucose metabolism under insulin-resistant conditions in primary visceral adipose tissue (VAT) from 31 patients with obesity and in murine 3T3-L1 adipocytes. In addition, in vitro studies in human VAT samples and mouse adipocytes were conducted to investigate the role of PKN1 in the adipogenic maturation process and glucose homeostasis control. We show that insulin-resistant adipocytes present a decrease in PKN1 activation levels compared to nondiabetic control counterparts. We further show that PKN1 controls the adipogenesis process and glucose metabolism. PKN1-silenced adipocytes present a decrease in both differentiation process and glucose uptake, with a concomitant decrease in the expression levels of adipogenic markers, such as PPARγ, FABP4, adiponectin and CEBPα. Altogether, these results point to PKN1 as a regulator of key signaling pathways involved in adipocyte differentiation and as an emerging player of adipocyte insulin responsiveness. These findings may provide new therapeutic approaches for the management of insulin resistance in type 2 diabetes.

MiR-422a promotes adipogenesis via MeCP2 downregulation in human bone marrow mesenchymal stem cells

Methyl-CpG binding protein 2 (MeCP2) is a ubiquitous transcriptional regulator. The study of this protein has been mainly focused on the central nervous system because alterations of its expression are associated with neurological disorders such as Rett syndrome. However, young patients with Rett syndrome also suffer from osteoporosis, suggesting a role of MeCP2 in the differentiation of human bone marrow mesenchymal stromal cells (hBMSCs), the precursors of osteoblasts and adipocytes. Here, we report an in vitro downregulation of MeCP2 in hBMSCs undergoing adipogenic differentiation (AD) and in adipocytes of human and rat bone marrow tissue samples. This modulation does not depend on MeCP2 DNA methylation nor on mRNA levels but on differentially expressed miRNAs during AD. MiRNA profiling revealed that miR-422a and miR-483-5p are upregulated in hBMSC-derived adipocytes compared to their precursors. MiR-483-5p, but not miR-422a, is also up-regulated in hBMSC-derived osteoblasts, suggesting a specific role of the latter in the adipogenic process. Experimental modulation of intracellular levels of miR-422a and miR-483-5p affected MeCP2 expression through direct interaction with its 3′ UTR elements, and the adipogenic process. Accordingly, the knockdown of MeCP2 in hBMSCs through MeCP2-targeting shRNA lentiviral vectors increased the levels of adipogenesis-related genes. Finally, since adipocytes released a higher amount of miR-422a in culture medium compared to hBMSCs we analyzed the levels of circulating miR-422a in patients with osteoporosis—a condition characterized by increased marrow adiposity—demonstrating that its levels are negatively correlated with T- and Z-scores. Overall, our findings suggest that miR-422a has a role in hBMSC adipogenesis by downregulating MeCP2 and its circulating levels are associated with bone mass loss in primary osteoporosis.

Prenylcysteine Oxidase 1 Is a Key Regulator of Adipogenesis

The process of adipogenesis involves the differentiation of preadipocytes into mature adipocytes. Excessive adipogenesis promotes obesity, a condition that increasingly threatens global health and contributes to the rapid rise of obesity-related diseases. We have recently shown that prenylcysteine oxidase 1 (PCYOX1) is a regulator of atherosclerosis-disease mechanisms, which acts through mechanisms not exclusively related to its pro-oxidant activity. To address the role of PCYOX1 in the adipogenic process, we extended our previous observations confirming that Pcyox1-/-/Apoe-/- mice fed a high-fat diet for 8 or 12 weeks showed significantly lower body weight, when compared to Pcyox1+/+/Apoe-/- mice, due to an evident reduction in visceral adipose content. We herein assessed the role of PCYOX1 in adipogenesis. Here, we found that PCYOX1 is expressed in adipose tissue, and, independently from its pro-oxidant enzymatic activity, is critical for adipogenesis. Pcyox1 gene silencing completely prevented the differentiation of 3T3-L1 preadipocytes, by acting as an upstream regulator of several key players, such as FABP4, PPARγ, C/EBPα. Proteomic analysis, performed by quantitative label-free mass spectrometry, further strengthened the role of PCYOX1 in adipogenesis by expanding the list of its downstream targets. Finally, the absence of Pcyox1 reduces the inflammatory markers in adipose tissue. These findings render PCYOX1 a novel adipogenic factor with possible pathophysiological or therapeutic potential.

Screening of lncRNA profiles during intramuscular adipogenic differentiation in longissimus dorsi and semitendinosus muscles in pigs

Intramuscular fat content is an important factor that determines meat quality in pigs. In recent years, epigenetic regulation has increasingly studied the physiological model of intramuscular fat. Although long noncoding RNAs (lncRNAs) play essential roles in various biological processes, their role in intramuscular fat deposition in pigs remains largely unknown. In this study, intramuscular preadipocytes in the longissimus dorsi and semitendinosus of Large White pigs were isolated and induced into adipogenic differentiation in vitro. High-throughput RNA-seq was carried out to estimate the expression of lncRNAs at 0, 2 and 8 days post-differentiation. At this stage, 2135 lncRNAs were identified. KEGG analysis showed that the differentially expressed lncRNAs were common in pathways involved with adipogenesis and lipid metabolism. lnc_000368 was found to gradually increase during the adipogenic process. Reverse-transcription quantitative polymerase chain reaction and a western blot revealed that the knockdown of lnc_000368 significantly repressed the expression of adipogenic genes and lipolytic genes. As a result, lipid accumulation in porcine intramuscular adipocytes was impaired by the silencing of lnc_000368. Overall, our study identified a genome-wide lncRNA profile related to porcine intramuscular fat deposition, and the results suggest that lnc_000368 is a potential target gene that might be targeted in pig breeding in the future.

RNA-Seq and lipidomics reveal different adipogenic processes between bovine perirenal and intramuscular adipocytes

ABSTRACT Adipogenesis involves complex interactions between transcription and metabolic signalling. Exploration of the developmental characteristics of intramuscular adipocyte will provide targets for enhancing beef cattle marbling without increasing obesity. Few reports have compared bovine perirenal and intramuscular adipocyte transcriptomes using the combined analysis of transcriptomes and lipid metabolism to explore differences in adipogenic characteristics. We identified perirenal preadipocytes (PRA) and intramuscular preadipocytes (IMA) in Qinchuan cattle. We found that IMA were highly prolific in the early stages of adipogenesis, while PRA shows a stronger adipogenic ability in the terminal differentiation. Bovine perirenal and intramuscular adipocytes were detected through the combined analysis of the transcriptome and metabolome. More triglyceride was found to be upregulated in perirenal adipocytes; however, more types and amounts of unsaturated fatty acids were detected in intramuscular adipocytes, including eicosapentaenoic acid (20:5 n-3; EPA) and docosahexaenoic acid (22:6 n-3; DHA). Furthermore, differentially expressed genes in perirenal and intramuscular adipocytes were positively correlated with the eicosanoid, phosphatidylcholine (PC), phosphatidyl ethanolamine (PE), and sphingomyelin contents. Associated differential metabolic pathways included the glycerolipid and glycerophospholipid metabolisms. Our research findings provide a basis for the screening of key metabolic pathways or genes and metabolites involved in intramuscular fat production in cattle.

Investigation of obesogenic effects of hexachlorobenzene, DDT and DDE in male rats

Obesity has become a very important public health problem and is increasing globally. Genetics, individual and environmental factors play roles in the etiology of this complex disorder. Recently, several environmental pollutants have been suggested to have obesogenic activities. Peroxisome proliferator activating receptor gamma (PPARγ), uncoupling protein-1 (UCP1) and their expression in white adipose tissue (WAT) and brown adipose tissue (BAT) play key roles in adipogenesis. UCP3 and irisin were reported to play roles in non-shivering thermogenesis. Our primary aim was to investigate obesogenic effects of hexachlorobenzene (HCB), dichlorodiphenyltrichloroethane (DDT) and dichlorodiphenyldichloroethylene (DDE) in rats. In addition, thermoregulatory effects of HCB, DDT and DDE were also investigated by analyzing the levels of Ucp3 and irisin. Thirty-two adult male Sprague-Dawley rats were randomly divided into four groups as control, HCB, DDT and DDE. Animals were administered with organochlorine pesticides (OCPs; 5 mg/kg bw) by oral gavage every other day for five weeks. At the end of the experimental period, the animals were sacrificed, BAT and WAT samples were collected to analyze Pparγ, Ucp1 and Ucp3 levels. Moreover, skeletal muscle samples were collected to examine Ucp3 and irisin levels. Serum glucose, cholesterol and triglyceride levels were also determined. Body weight and core temperature of the animals were not significantly affected by any of the OCP administration. Serum glucose, cholesterol and triglyceride levels were similar among the experimental groups. Pparγ expression was significantly elevated by HCB administration only in WAT (p < 0.05). On the other hand, both Pparγ and Ucp1 expressions were diminished in WAT and BAT (p < 0.01) by DDT treatment, while in WAT, DDE significantly decreased Pparγ expression without altering its expression in BAT (p < 0.001). Ucp3 and irisin levels in skeletal muscle were not altered. Our findings show that both DDT and DDE reduce the browning of WAT by suppressing white adipocytes and thus may have obesogenic activity in male rats without altering thermoregulation. In addition, HCB, DDT and DDE-induced alterations in expression of Pparγ and Ucp1 in WAT implicates differential regulation of adipogenic processes.