Promotes Adipocyte Differentiation Research Articles

A keratinocyte-adipocyte signaling loop is reprogrammed by loss of BTG3 to augment skin carcinogenesis.

Obesity is endemic to many developed countries. Overweight or obesity is associated with an increased risk of developing cancer. Dysfunctional adipose tissue alters cancer cell proliferation and migration; however, whether and how neoplastic epithelial cells communicate with adipose tissue and the underlying mechanism are less clear. BTG3 is a member of the anti-proliferative BTG/Tob family and functions as a tumor suppressor. Here, we demonstrated that BTG3 levels are downregulated in basal cell carcinoma and squamous cell carcinoma compared to normal skin tissue, and Btg3 knockout in mice augmented the development of papilloma in a mouse model of DMBA/TPA-induced skin carcinogenesis. Mechanistically, BTG3-knockout keratinocytes promoted adipocyte differentiation mainly through the release of IL1α, IL10, and CCL4, as a result of elevated NF-κB activity. These adipocytes produced CCL20 and FGF7 in a feedback loop to promote keratinocyte migration. Thus, our findings showcased the role of BTG3 in guarding the interplay between keratinocytes and adjacent adipocytes, and identified the underlying neoplastic molecular mediators that may serve as possible targets in the treatment of skin cancer.

Deletion of CD44 promotes adipogenesis by regulating PPARγ and cell cycle-related pathways.

CD44, a cell surface adhesion receptor and stem cell biomarker, is recently implicated in chronic metabolic diseases. Ablation of CD44 ameliorates adipose tissue inflammation and insulin resistance in obesity. Here, we investigated cell type-specific CD44 expression in human and mouse adipose tissue and further studied how CD44 in preadipocytes regulates adipocyte function. Using Crispr Cas9-mdediated gene deletion and lentivirus-mediated gene re-expression, we discovered that deletion of CD44 promotes adipocyte differentiation and adipogenesis, whereas re-expression of CD44 abolishes this effect and decreases insulin responsiveness and adiponectin secretion in 3T3-L1 cells. Mechanistically, CD44 does so via suppressing Pparg expression. Using quantitative proteomics analysis, we further discovered that cell cycle-regulated pathways were mostly decreased by deletion of CD44. Indeed, re-expression of CD44 moderately restored expression of proteins involved in all phases of the cell cycle. These data were further supported by increased preadipocyte proliferation rates in CD44-deficient cells and re-expression of CD44 diminished this effect. Our data suggest that CD44 plays a crucial role in regulating adipogenesis and adipocyte function possibly through regulating PPARγ and cell cycle-related pathways. This study provides evidence for the first time that CD44 expressed in preadipocytes plays key roles in regulating adipocyte function outside immune cells where CD44 is primarily expressed. Therefore, targeting CD44 in (pre)adipocytes may provide therapeutic potential to treat obesity-associated metabolic complications.

The Function and Mechanism of Anti-Inflammatory Factor Metrnl Prevents the Progression of Inflammatory-Mediated Pathological Bone Osteolytic Diseases.

Metrnl, recently identified as an adipokine, is a secreted protein notably expressed in white adipose tissue, barrier tissues, and activated macrophages. This adipokine plays a pivotal role in counteracting obesity-induced insulin resistance. It enhances adipose tissue functionality by promoting adipocyte differentiation, activating metabolic pathways, and exerting anti-inflammatory effects. Extensive research has identified Metrnl as a key player in modulating inflammatory responses and as an integral regulator of muscle regeneration. These findings position Metrnl as a promising biomarker and potential therapeutic target in treating inflammation-associated pathologies. Despite this, the specific anti-inflammatory mechanisms of Metrnl in immune-mediated osteolysis and arthritis remain elusive, warranting further investigation. In this review, we will briefly elaborate on the role of Metrnl in anti-inflammation function in inflammation-related osteolysis, arthritis, and pathological bone resorption, which could facilitate Metrnl's clinical application as a novel therapeutic strategy to prevent bone loss. While the pathogenesis of elbow stiffness remains elusive, current literature suggests that Metrnl likely exerts a pivotal role in its development.

SOD2 promotes the immunosuppressive function of mesenchymal stem cells at the expense of adipocyte differentiation

The potent immunomodulatory function of mesenchymal stem/stromal cells (MSCs) elicited by proinflammatory cytokines IFN-γ and TNF-α (IT) is critical to resolve inflammation and promote tissue repair. However, little is known about how the immunomodulatory capability of MSCs is related to their differentiation competency in the inflammatory microenvironment. In this study, we demonstrate that the adipocyte differentiation and immunomodulatory function of human adipose tissue-derived MSCs (MSC(AD)s) are mutually exclusive. Mitochondrial reactive oxygen species (mtROS), which promote adipocyte differentiation, were decreased in MSC(AD)s due to IT-induced upregulation of superoxide dismutase 2 (SOD2). Furthermore, knockdown of SOD2 led to enhanced adipogenic differentiation but reduced immunosuppression capability of MSC(AD)s. Interestingly, the adipogenic differentiation was associated with increased mitochondrial biogenesis and upregulation of peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PPARGC1A/PGC-1α) expression. IT inhibited PGC-1α expression and decreased mitochondrial mass but promoted glycolysis in an SOD2-dependent manner. MSC(AD)s lacking SOD2 were compromised in their therapeutic efficacy in DSS-induced colitis in mice. Taken together, these findings indicate that the adipogenic differentiation and immunomodulation of MSC(AD)s may compete for resources in fulfilling the respective biosynthetic needs. Blocking of adipogenic differentiation by mitochondrial antioxidant may represent a novel strategy to enhance the immunosuppressive activity of MSCs in the inflammatory microenvironment.

Methylation of lncSHGL promotes adipocyte differentiation by regulating miR-149/Mospd3 axis

ABSTRACT Obesity poses significant health risks and can negatively impact an individual’s quality of life. The human obesity phenotype results from the differentiation of pre-adipocytes into adipocytes, which leads to hypertrophy and hyperplasia in adipose tissue. The molecular mechanisms by which long non-coding RNAs (lncRNAs) modulate adipocyte differentiation, a process implicated in obesity development, remain poorly characterized. A lncRNA which suppressed the hepatic gluconeogenesis and lipogenesis (lncSHGL) was newly identified. Our research aims to elucidate the functional role and mechanistic underpinnings of suppressor of lncSHGL in adipocyte differentiation. We observed that lncSHGL expression progressively diminished during 3T3-L1 differentiation and was downregulated in the liver and perirenal adipose tissue of ob/ob mice. lncSHGL acts as a molecular sponge for miR-149, with Mospd3 identified as a target of miR-149.Overexpression of lncSHGL and inhibition of miR-149 led to suppressed 3T3-L1 proliferation, decreased lipid droplet accumulation, and attenuated promoter activity of PPARγ2 and C/EBPα. These changes consequently resulted in reduced expression of Cyclin D1, LPL, PPARγ2, AP2, and C/EBPα, as well as inhibited the PI3K/AKT/mTOR signaling pathway. In contrast, lncSHGL suppression yielded opposing outcomes. Moreover, the effects of lncSHGL overexpression and miR-149 inhibition on reduced expression of Cyclin D1, LPL, PPARγ2, AP2, and C/EBPα were reversible upon miR-149 overexpression and Mospd3 suppression. These findings were further validated in vivo. We also discovered a significant increase in methylation levels during 3T3-L1 differentiation, with lncSHGL highly expressed in the presence of a methylation inhibitor. In conclusion. lncSHGL methylation facilitates adipocyte differentiation by modulating the miR-149/Mospd3 axis. Targeting lncSHGL expression may represent a promising therapeutic strategy for obesity-associated adipogenesis, particularly in the context of fatty liver disease.

BK Channel Depletion Promotes Adipocyte Differentiation by Activating the MAPK/ERK Pathway.

The expression of large conductance calcium-activated potassium channels (BK channels) in adipose tissue has been identified for years. BK channel deletion can improve metabolism in vivo, but the relative mechanisms remain unclear. Here, we examined the effects of BK channels on the differentiation of adipose-derived stem cells (ADSCs) and the related mechanisms. BKα and β1 subunits were expressed on adipocytes. We found that both deletion of the KCNMA1 gene, encoding the pore forming α subunit of BK channels, and the BK channel inhibitor paxilline increased the expression of key genes in the peroxisome proliferator activated receptor (PPAR) pathway and promoted adipogenetic differentiation of ADSCs. We also observed that the MAPK-ERK pathway participates in BK channel deficiency-promoted adipogenic differentiation of ADSCs and that ERK inhibitors blocked the differentiation-promoting effect of BK channel deficiency. Hyperplasia of adipocytes is considered beneficial for metabolic health. These results indicate that BK channels play an important role in adipose hyperplasia by regulating the differentiation of ADSCs and may become an important target for studying the pathogenesis and treatment strategies of metabolic disorder-related diseases.

Foxk1 stimulates adipogenic differentiation via a peroxisome proliferator-activated receptor gamma 2-dependent mechanism.

Adipogenesis is a tightly regulated process, and its dysfunction has been linked to metabolic disorders such as obesity. Forkhead box k1 (Foxk1) is known to play a role in the differentiation of myogenic precursor cells and tumorigenesis of different types of cancers; however, it is not clear whether and how it influences adipocyte differentiation. Here, we found that Foxk1 was induced in mouse primary bone marrow stromal cells (BMSCs) and established mesenchymal progenitor/stromal cell lines C3H/10T1/2 and ST2 after adipogenic treatment. In addition, obese db/db mice have higher Foxk1 expression in inguinal white adipose tissue than nonobese db/m mice. Foxk1 overexpression promoted adipogenic differentiation of C3H/10T1/2, ST2 cells and BMSCs, along with the enhanced expression of CCAAT/enhancer binding protein-α, peroxisome proliferator-activated receptor γ (Pparγ), and fatty acid binding protein 4. Moreover, Foxk1 overexpression enhanced the expression levels of lipogenic factors during adipogenic differentiation in both C3H/10T1/2 cells and BMSCs. Conversely, Foxk1 silencing impaired these cells from fully differentiating. Furthermore, adipogenic stimulation induced the nuclear translocation of Foxk1, which depended on the mTOR and PI3-kinase signaling pathways. Subsequently, Foxk1 is directly bound to the Pparγ2 promoter, stimulating its transcriptional activity and promoting adipocyte differentiation. Collectively, our study provides the first evidence that Foxk1 promotes adipocyte differentiation from progenitor cells by promoting nuclear translocation and upregulating the transcriptional activity of the Pparγ2 promoter during adipogenic differentiation.

A novel berberine derivative targeting adipocyte differentiation to alleviate TNF-α-induced inflammatory effects and insulin resistance in OP9 cells

Inflammation and insulin resistance play important roles in the development and progression of type 2 diabetes mellitus. The enhancement of adipocyte differentiation can improve insulin sensitivity by increasing glucose uptake, improving insulin signaling, and reducing inflammation. However, only a few adipogenic agents have shown clinical success in patients with type 2 diabetes mellitus. The therapeutic potential of berberine in type 2 diabetes mellitus was confirmed in terms of the target gene-disease relationship using a network pharmacology database prior to synthesizing the derivatives. Novel berberine derivatives were synthesized, and compound 3b promoted adipocyte differentiation and improvement of insulin resistance in OP9 cells. Compound 3b significantly increased the expression of key adipogenic markers including peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein β (C/EBPβ) and promoted lipid accumulation without cytotoxicity. Furthermore, tumor necrosis factor α (TNF-α)-induced inhibition of adipocyte differentiation and the elevation of inflammatory responses were reversed by compound 3b. Subsequently glucose uptake level through insulin sensitivity improvement was enhanced by compound 3b. Mechanistically, TNF-α activated mitogen-activated protein kinases (MAPKs): ERK, JNK, and p38, whereas compound 3b attenuated phosphorylation of three MAPKs. Finally, in silico molecular docking suggested the possible binding sites of compound 3b on PPARγ. Collectively, the adipogenic and glucose uptake effects of compound 3b were associated with its anti-inflammatory effects and reduced phosphorylation of MAPKs. These findings suggest that the berberine derivative compound 3b may be a potent antidiabetic agent.

APE1/REF-1 AFFECTS ADIPOCYTE DIFFERENTIATION BY REGULATING ADIPOGENIC TRANSCRIPTION FACTORS IN 3T3-L1 CELLS

Objective: Apurinic/apyrimidinic endonuclease 1/redox factor-1 (APE1/Ref-1) is a multifunctional protein involved in DNA repair and redox regulation. The redox activity of APE1/Ref-1 is involved in inflammatory responses and regulation of DNA binding of transcription factors related to cell survival pathways. Design and method: To determine the changes in APE1/Ref-1 expression during the adipogenic differen-tiation of preadipocytes, we investigated APE1/Ref-1 expression on days 0, 2, 4, 6, and 8 of 3T3-L1 cell differentiation (Figure 1A) To evaluate the effect of APE1/Ref-1 on MDI-induced adipocyte differentiation, 3T3-L1 cells were transfected with adenovirus expressing APE1/Ref-1. Having established that overexpression of APE1/Ref-1 suppressed adipocyte differ-entiation, the effect of gene silencing of APE1/Ref-1 during MDI-induced adipocyte differ-entiation was evaluated in 3T3-L1 cells with transfection of APE1/Ref-1 siRNA. Finally, the effect of E3330, a redox inhibitor of APE1/Ref-1, on adipocyte differentiation was evaluated in 3T3-L1 cells. Results: In this study, we investigated the effect of APE1/Ref-1 on the regulation of adi-pocyte differentiation in 3T3-L1 cells. During adipocyte differentiation, APE1/Ref-1 expression sig-nificantly decreased with the increased expression of adipogenic transcription factors such as CCAAT/enhancer binding protein (C/EBP)-alpha and peroxisome proliferator-activated receptor gamma, and the adipocyte differentiation marker adipocyte protein 2 (aP2) in a time-dependent manner. However, APE1/Ref-1 overexpression inhibited C/EBP-alpha, PPAR-gamma, and aP2 expression, which was upregulated during adipocyte differentiation. In contrast, silencing APE1/Ref-1 or redox inhibition of APE1/Ref-1 using E3330 increased the mRNA and protein levels of C/EBP-alpha, PPAR-gamma, and aP2 during adipocyte differentiation. Conclusions: In conclusion, our study demonstrated that endogenous APE1/Ref-1 is downregu-lated during adipocyte differentiation, whereas overexpression of APE1/Ref-1 inhibits ad-ipocyte differentiation; in contrast, silencing APE1/Ref-1 and redox inhibition using E3330 promotes adipocyte differentiation through the modulation of expression of adipogenic transcriptional factors. Overall, these results suggest that the redox function of APE1/Ref-1 exerts an anti-adipogenic function by inhibiting adipocyte differentiation.

Abstract 72: Ablation of WNT10B alters the tumor microenvironment in highly metastatic breast cancer, altering paclitaxel response

Abstract Triple-negative breast cancer (TNBC) has the worst survival outcome and the greatest incidence of metastasis among breast cancer subtypes. We have shown that the WNT10B network, composed of β-CATENIN, HMGA2, and EZH2, is predictive of higher rates of TNBC metastasis and poorer overall survival in TNBC. The stroma-tumor microenvironment (TME) interactions in metastatic breast cancer remain poorly defined, and prior to our work, the role of WNT10B signaling in the TME was unknown. Global gene expression profiling of the Wnt10bKO total mammary glands demonstrated a gene signature consistent with altered metabolism and markers promoting adipocyte differentiation. Wnt10b ablation in the mammary gland increases adipogenic differentiation and decreases the number of mammary gland terminal-end buds, and epithelia to stroma/fibroblast cell ratios. Therefore, we questioned the role of WNT10B in stromal cancer-associated fibroblast (CAFs) and cancer-associated adipocytes (CAAs) in the TME of transformed mammary glands. By backcrossing our Wnt10bKO mice to the highly metastatic MMTV-PyMT (PyMT) transgenic mammary tumor model, we demonstrated alteration in the age of tumor onset, changes in the incidence of transformation of thoracic and abdominal-inguinal tumors, and impacts on survival rates. Moreover, adipogenic markers are higher and persist through transformation in PyMTWnt10bKO mice compared to PyMT mice. Proliferation, migration, and invasion are also impacted in the PyMTWnt10bKO CAFs when co-cultured with PyMT tumor cells. The ability of PyMTWnt10bKO CAFs to alter cellular plasticity and generate CAAs is higher than PyMT CAFs. Additionally, PyMTWnt10bKO CAFs lose expression of canonical Wnt markers DVL and LRP and gain non-canonical Wnt signaling via WNT5B/ROR pathways that persist in the KO CAAs. We also observed alterations in chemoresistance in KO tumor epithelium. The resistance to paclitaxel from enriched PyMT epithelia from thoracic tumors was higher than epithelia enriched from the abdominal-inguinal tumors. Interestingly, the Wnt10bKO TME inverted the response to paclitaxel and the abdominal-inguinal epithelial tumor cells were more resistant than those from the thoracic epithelium. Furthermore, resistance to paclitaxel was associated with higher responses to PRI-724, a CBP-β-CATENIN inhibitor. Neither WT nor KO epithelial subtypes were resistant to olaparib exposure. Therefore, we conclude that Wnt10b is essential to educate highly metastatic breast cancer stromal cells to promote growth, metastatic colonization, and resistance to paclitaxel. Citation Format: Hannah R. Kelso, Rachel S. Perkins, Ikbale El Ayachi, Jackelyn A. Alva-Ornelas, Tiffany N. Seagroves, Victoria L. Seewaldt, Susan A. Krum, Gustavo Adolfo Miranda-Carboni. Ablation of WNT10B alters the tumor microenvironment in highly metastatic breast cancer, altering paclitaxel response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 72.

Downregulation of miRNA-155–5p contributes to the adipogenic activity of 2-ethylhexyl diphenyl phosphate in 3T3-L1 preadipocytes

2-Ethylhexyl diphenyl phosphate (EHDPP) is a commonly used organophosphorus flame retardant and food packaging material. Because of its high lipophilic and bioaccumulative properties, adipocytes are the primary target of EHDPP. However, the toxicity of EHDPP on preadipocytes and the potential mechanism have not been fully elucidated. MicroRNAs (miRNAs) are thought to be an important mediator that contribute to the toxicity of environmental contaminants. To identify the miRNAs specifically responsible for EHDPP exposure and their role in EGDPP’s toxicity in preadipocytes, the adipogenic effects and miRNA expression profiling were performed on 3T3-L1 preadipocytes exposed to EHDPP. EHDPP at concentrations of 1–10 μM promoted adipocyte differentiation, as evidenced by lipid staining, triglyceride content, and expression of adipogenesis markers. MiRNA-seq analysis revealed that 7 differentially expressed miRNAs were recognized under EHDPP exposure, with miR-155–5p being the top down-regulated miRNA. Quantitative reverse transcription PCR (RT-qPCR) analysis showed that miR-155–5p level fell sharply during the first 2 days and continued to fall dose-dependently throughout the EHDPP exposure period. MiR-155–5p inhibition promotes adipocyte differentiation, whereas its overexpression counteracted EHDPP-induced adipogenesis. Luciferase reporter assay identified CCAAT/enhancer-binding protein beta (C/EBPβ) as a target of miR-155–5p in 3T3-L1 preadipocytes in response to EHDPP. Taken together, EHDPP exposure down-regulated miR-155–5p, which then increased C/EBPβ and peroxisome proliferator-activated receptor γ (PPARγ) expression and promoted adipogenesis in preadipocytes.

Mechanic Insight into the Distinct and Common Roles of Ovariectomy Versus Adrenalectomy on Adipose Tissue Remodeling in Female Mice.

Dysfunctions of the ovaries and adrenal glands are both evidenced to cause aberrant adipose tissue (AT) remodeling and resultant metabolic disorders, but their distinct and common roles are poorly understood. In this study, through biochemical, histological and RNA-seq analyses, we comprehensively explored the mechanisms underpinning subcutaneous (SAT) and visceral adipose tissue (VAT) remodeling, in response to ovariectomy (OVX) versus adrenalectomy (ADX) in female mice. OVX promoted adipocyte differentiation and fat accumulation in both SAT and VAT, by potentiating the Pparg signaling, while ADX universally prevented the cell proliferation and extracellular matrix organization in both SAT and VAT, likely by inactivating the Nr3c1 signaling, thus causing lipoatrophy in females. ADX, but not OVX, exerted great effects on the intrinsic difference between SAT and VAT. Specifically, ADX reversed a large cluster of genes differentially expressed between SAT and VAT, by activating 12 key transcription factors, and thereby caused senescent cell accumulation, massive B cell infiltration and the development of selective inflammatory response in SAT. Commonly, both OVX and ADX enhance circadian rhythmicity in VAT, and impair cell proliferation, neurogenesis, tissue morphogenesis, as well as extracellular matrix organization in SAT, thus causing dysfunction of adipose tissues and concomitant metabolic disorders.

Chordin Like-1 Regulates Osteoblast and Adipocyte Differentiation Through Stabilizing Insulin-Like Growth Factor Binding Protein 3.

Chordin like-1 (CHRDL1) is an antagonist of bone morphogenetic proteins (BMPs) that acts through binding BMPs and blocking their interaction with BMP receptors. CHRDL1 plays a role in osteoblast differentiation but controversial effects were reported. On the other hand, the role of CHRDL1 in adipogenesis is unknown. In the present study, we investigated the function of CHRDL1 in regulating differentiation of osteoblasts and adipocytes and elucidated the underlying mechanism. CHRDL1 expression was downregulated during osteogenesis while it was upregulated during adipogenesis in primary cultured and established mesenchymal progenitor cell lines. Functional experiments revealed that CHRDL1 suppressed osteoblast differentiation and promoted adipocyte differentiation. Mechanistic explorations revealed that CHRDL1 is directly bound to insulin-like growth factor binding protein 3 (IGFBP3) and attenuated the degradation of the latter. Furthermore, CHRDL1 and IGFBP3 suppressed the activity of insulin receptor substrate 1 (IRS1)/AKT serine/threonine kinase (AKT)/mechanistic target of rapamycin kinase complex 1 (mTORC1) signaling in progenitor cells undergoing osteogenic differentiation. By contrast, they activated AKT/mTORC1 signaling independently of IRS1 during adipogenic differentiation. CHRDL1 enhanced the interaction of nuclear IGFBP3 and retinoid X receptor α (RXRα) during adipogenesis, and inhibition of RXR inactivated AKT and attenuated the stimulation of adipogenic differentiation by CHRDL1. Overexpression of IGFBP3 relieved the perturbation of osteogenic and adipogenic differentiation of progenitor cells induced by CHRDL1 silencing. Finally, CHRDL1 and IGFBP3 were upregulated in the trabecular bone of aged mice. Our study provides evidence that CHRDL1 reciprocally regulates osteoblast and adipocyte differentiation through stabilizing IGFBP3 and differentially modulating AKT/mTORC1 signaling.

N-myc Downstream Regulated Gene 1 Promotes Adipocyte Differentiation in Endothelial Cells of Infantile Hemangioma.

N-myc Downstream Regulated Gene 1 Promotes Adipocyte Differentiation in Endothelial Cells of Infantile Hemangioma.

Hydrogen Sulfide Promotes Adipocyte Differentiation, Hyperplasia, and Hypertrophy

Hydrogen sulfide (H2S) is endogenously produced in adipocytes and fat tissues and stimulates adipogenesis. The integrated pathogenic effects of H2S on the development of obesity and the underlying mechanisms, however, have been unclear. Here, we find that a decreased endogenous H2S level lowered lipid accumulation in mouse adipocytes. Exogenous H2S treatment significantly increased the adipogenesis of primary mouse preadipocytes after six days of adipogenic induction. In the early phase of adipogenesis, H2S increased cell proliferation and prepared cells to go through hyperplasia. After H2S treatment for ten days, preadipocytes exhibited significantly greater cell surface area and diameter, indicating cell hypertrophy. Although it stimulated lipid accumulation and adipogenesis, H2S had no effect on lipolysis. With nutrition overload and high glucose/insulin incubation, H2S further stimulated glucose consumption and deteriorated adipocyte hypertrophy. H2S upregulated hyperplasia genes (CCAAT/enhancer-binding protein (C/EBPβ), cell division cycle 25 (Cdc25), minichromosome maintenance 3 (Mcm3), and cell division cycle (Cdc45)) and cyclin-dependent kinase 2 protein (Cdk2), which regulates cell proliferation. H2S also upregulated the insulin receptor β (Irβ)-activated mitogen-activated protein kinase (MAPK) and protein kinase B (Akt) pathways, leading to adipogenesis. In conclusion, H2S increases adipocyte differentiation, hypertrophy, and hyperplasia, implying that it plays a pathogenic role in obesity disorder.

The fat accumulation promotion effects of dihydrxytetraphenylmethane and its underlying mechanisms via transcriptome analysis

Dihydrxytetraphenylmethane, also known as Bisphenol BP (BPBP), has been increasingly used in industrial production and more frequently detected in the environment as an alternative plasticizer of BPA. However, there are no reports about BPBP in food safety or its effects on cellular lipogenesis. The purpose of this research was to investigate the influence and potential mechanisms of BPBP on adipogenesis in 3T3-L1 cells. Cells were treated with 4 concentrations (0.01, 0.1, 1, and 10 μM) of BPBP and the results showed that treatment with at low concentrations (0.01 μM) promoted cell fat differentiation and triglyceride accumulation. RNA-seq data showed that a total of 370 differentially expressed genes between control and the low-dose BPBP-treated group were determined, including 227 upregulated genes and 143 downregulated genes. Some key genes related to adipocyte differentiation and adipogenesis were significantly enriched after BPBP treatment, including PPAR-γ, Adipoq, Nr1h3 and Plin1. Pathway analyses suggest that the activation of PPAR-γ signaling pathway may be key for BPBP to promote adipocyte differentiation and fat accumulation. Our work provides evidence for the potential obesogenic effect of BPBP and may call for further research on the safety of the chemical in food products.

The novel importance of miR-143 in obesity regulation

Obesity and substantially increased risk of metabolic diseases have become a global epidemic. microRNAs have attracted a great deal of attention as a potential therapeutic target for obesity. MiR-143 has been known to specifically promote adipocyte differentiation by downregulating extracellular signal-regulated kinase 5. Our latest study found that miR-143 knockout is against diet-induced obesity by promoting brown adipose tissue thermogenesis and inhibiting white adipose tissue adipogenesis. Moreover, LPS- or IL-6-induced inhibition of miR-143 expression in brown adipocytes promotes thermogenesis by targeting adenylate cyclase 9. In this review, we will summarize the expression and functions of miR-143 in different tissues, the influence of obesity on miR-143 in various tissues, the important role of adipose-derived miR-143 in the development of obesity, the role of miR-143 in immune cells and thermoregulation and discuss the potential significance and application prospects of miR-143 in obesity management.

Valerenic Acid Promotes Adipocyte Differentiation, Adiponectin Production, and Glucose Uptake via Its PPARγ Ligand Activity.

Although valerenic acid (VA) is an important marker compound for quantitative assessment of Valeriana officinalis products, little is known about its potential effects on adipocytes. We investigated the effects of VA on adipocyte differentiation, adiponectin production, and glucose uptake using 3T3-L1 adipocytes. The results showed that VA promoted adipocyte differentiation and increased the gene expression of adipogenesis and glucose uptake-related proteins, including peroxisome proliferator-activated receptor gamma (PPARγ), cytosine-cytosine-adenosine-adenosine-thymidine enhancer binding protein alpha (C/EBPα), adiponectin, and glucose transporter 4 (GLUT4). Additionally, cell cultures treated with VA had elevated adiponectin secretion and glucose uptake. The PPARγ luciferase assay indicated VA as a partial agonist of PPARγ, while the analysis using its antagonist, GW9662, and a docking simulation between PPARγ and VA revealed the binding site of VA as likely adjacent to the Ω loop pocket of PPARγ. Taken together, these results demonstrate that VA acts as a PPARγ partial agonist to promote adipocyte differentiation, adiponectin production, and glucose uptake.

RF12 | PSUN106 Quantifying Liver and Brain Levels of 11β-hydroxysteroid Dehydrogenase Type 1 in Obesity Using Positron Emission Tomography Imaging

Abstract Objectives Cortisol is known to promote adipocyte differentiation and maturation, and prolonged exposure to excess cortisol contributes to the development of obesity and metabolic dysregulation. The intracellular 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) enzyme catalyzes the conversion of inactive cortisone to active cortisol. Recently, we demonstrated reduced brain 11β-HSD1 levels in vivo with increasing body mass index (BMI), using positron emission tomography (PET) radioligands [11C]- and [18F]AS2471907(1). PET imaging can simultaneously quantify uptake in multiple organs (e.g., liver/brain). [18F]AS2471907 has high uptake and specific binding in the brain and liver(2). Liver and brain 11β-HSD1 measured by PET imaging may help elucidate the roles of cortisol activation in the setting of metabolic dysregulation. Thus, we performed PET imaging studies to examine 11β-HSD1 levels in the liver and brain. Methods Nine individuals (5F/4M) with a range of BMIs (22.6-34.4 kg/m2) underwent a 90 min PET/CT acquisition with arterial plasma sampling after injection of [18F]AS2471907. Regions-of-interest (ROI) for the liver were manually drawn on a summed PET image (60-90 min). Seventeen brain ROIs were selected from the anatomical automatic labeling (AAL) template and applied to the dynamic PET images to generate time-activity-curves (TACs). Brain volume of distribution (VT, mL/cm3), the target tissue to plasma ratio of radioligand at equilibrium, was estimated for each ROI using the multilinear analysis-1 method with plasma input function. Mean whole-brain VT values were calculated by averaging all ROIs. Given the appearance of irreversible kinetics in the liver, Ki (min-1), the rate of irreversible tracer uptake, was calculated using the Patlak method. Results Qualitative brain and liver uptake was assessed by examining a summed PET image (SUV 60-90min). The parent fraction in plasma was 88±1% at 90 min, indicating negligible plasma radiolabeled-metabolites contributing the measured signal in the liver. Kinetic modeling estimates demonstrated decreasing whole brain VT with increasing BMI (R2=0.53), similar to our previously published study examining only brain in a larger cohort(1). Patlak methods provided good estimates of Ki. In an opposite manner from the brain, correlations seen in the liver using Ki were positively correlated with BMI (R2=0.57). Conclusions These preliminary studies suggest obesity is associated with increased 11β-HSD1 levels in the liver but decreased 11β-HSD1 levels in the brain. Clinically, liver specific 11β-HSD1 inhibitors may prove beneficial in treating metabolic sequalae of obesity such non-alcoholic fatty liver disease (NAFLD) by inhibiting activity of higher 11β-HSD1 levels. Further studies in NAFLD and obesity are necessary to determine appropriate populations that would benefit from 11β-HSD1 inhibitors and longitudinal in vivo PET imaging to help inform development of future therapeutics.

FTO promoted adipocyte differentiation by regulating ADRB1 gene through m6A modification in Hycole rabbits

N6-methyladenosine (m6A), the most abundant internal mRNA modification in eukaryotes, plays a vital role in regulating adipogenesis. However, its underlying mechanism remains largely unknown. Our previous study found that ADRB1 gene has m6A modification in both muscle and fat tissue. In this study, we interfered with FTO and ADRB1 genes After we cultured rabbit preadipocytes respectively. Oil red O staining and triglyceride assay were used to detect adipocyte differentiation. RT-qPCR was used to detect gene expression level and MeRIP-qPCR was used to detect the m6A modification level of gene. The results showed that FTO promoted the differentiation of adipocytes. At the same time, FTO up regulated the expression of ADRB1 gene and down regulated the m6A modification level of ADRB1 gene. Finally, we found that ADRB1 inhibited adipocyte differentiation. Together, we showed that FTO promoted adipocyte differentiation by regulating ADRB1 gene through m6A modification.