Transcriptional and Epigenomic Regulation of Adipogenesis. Mol Cell Biol. 2019;39. [PMID: 30936246 DOI: 10.1128/mcb.00601-18]

Inhibition of AHCY impedes proliferation and differentiation of mouse and human adipocyte progenitor cells

S-adenosyl-homocysteine-hydrolase (AHCY) plays an important role in the methionine cycle regulating cellular methylation levels. AHCY has been reported to influence proliferation and differentiation processes in different cell types, e.g. in cancer cells and mouse embryonic stem cells. In the development of adipose tissue, both the proliferation and differentiation of adipocyte progenitor cells (APCs) are important processes, which in the context of obesity are often dysregulated. To assess whether AHCY might also be involved in cell proliferation and differentiation of APCs, we investigated the effect of reduced AHCY activity on human and mouse APCs in vitro. We show that the inhibition of AHCY using adenosine dialdehyde (AdOx) and the knockdown of AHCY using gene-specific siRNAs reduced APC proliferation and number. Inhibition of AHCY further reduced APC differentiation into mature adipocytes and the expression of adipogenic differentiation markers. Global DNA methylation profiling in human APCs revealed that inhibition of AHCY is associated with alterations in CpG methylation levels of genes involved in fat cell differentiation and pathways related to cellular growth. Our findings suggest that AHCY is necessary for the maintenance of APC proliferation and differentiation and inhibition of AHCY alters DNA methylation processes leading to a dysregulation of the expression of genes involved in the regulation of these processes.

The Role of Adipose Tissue and Nutrition in the Regulation of Adiponectin

Adipose tissue (AT), composed mainly of adipocytes, plays a critical role in lipid control, metabolism, and energy storage. Once considered metabolically inert, AT is now recognized as a dynamic endocrine organ that regulates food intake, energy homeostasis, insulin sensitivity, thermoregulation, and immune responses. This review examines the multifaceted role of adiponectin, a predominant adipokine released by AT, in glucose and fatty acid metabolism. We explore the regulatory mechanisms of adiponectin, its physiological effects and its potential as a therapeutic target for metabolic diseases such as type 2 diabetes, cardiovascular disease and fatty liver disease. Furthermore, we analyze the impact of various dietary patterns, specific nutrients, and physical activities on adiponectin levels, highlighting strategies to improve metabolic health. Our comprehensive review provides insights into the critical functions of adiponectin and its importance in maintaining systemic metabolic homeostasis.

Cell Fate Regulation During the Development of Infantile Hemangioma

As the most common benign vascular tumor in infants, infantile hemangioma (IH) is characterized by rapid growth and vasculogenesis early in infancy, followed by spontaneous involution into fibrofatty tissues over time. Extensive evidence suggests that IH originates from hemangioma stem cells (HemSCs), a group of stem cells with clonal expansion and multi-directional differentiation capacity. However, the intricate mechanisms governing the cell fate transition of HemSCs during IH development remain elusive. Here we comprehensively examine the cellular composition of IH, emphasizing the nuanced properties of various IH cell types and their correlation with the clinical features of the tumor. We also summarize the current understanding of the regulatory pathways directing HemSC differentiation into endothelial cells (ECs), pericytes, and adipocytes throughout the stages of IH progression and involution. Furthermore, we discuss recent advances in unraveling the transcriptional and epigenetic regulation of EC and adipocyte development under physiological conditions, which offer crucial perspectives for understanding IH pathogenesis.

A review: Interactions between protein from blue foods and functional components in delivery systems: Function exertion and transmembrane transport by in vitro digestion/cells model

Functional compounds (FCs) had some functions, which are affected easily by digestion and transmembrane transport leading to low absorption rates, such as lutein, quercetin, xylo-oligosaccharide. Protein from blue foods is a potential bioactive compound, which had higher bioavailability, especially for bioactive peptides (BBPs). The BBPs has great limitations, especially the variability under pepsin digestion. However, the limitation of single FCs and BBPs in bioavailability might can be complemented by mixture of different bioactive compounds. Therefore, this review provides an in-depth study on the function and mechanism of different FCs/BBPs and their mixtures. Specifically, digestion effect of mixtures on function and transmembrane transport mechanisms of different bioactive compounds were exhibited to elaborate interactions between BBPs and FCs in delivery systems (function and bioavailability). Combination of FCs/BBPs could enhance bioactive compounds function by mutual complement of function mechanisms, as well as improving the function after digestion by regulating digestion process. Moreover, transmembrane absorption and transport of FCs/BBPs also could be facilitated by mixtures due to complement of transmembrane mechanism (endocytosis, protein channels, cell bypass way). This manuscript lays a foundation for the development of active ingredient bioavailability in functional food processing.

Genome-wide Methylation Dynamics and Context-dependent Gene Expression Variability in Differentiating Preadipocytes

Obesity, characterized by the accumulation of excess fat, is a complex condition resulting from the combination of genetic and epigenetic factors. Recent studies have found correspondence between DNA methylation and cell differentiation, suggesting a role of the former in cell fate determination. There is a lack of comprehensive understanding concerning the underpinnings of preadipocyte differentiation, specifically when cells are undergoing terminal differentiation (TD). To gain insight into dynamic genome-wide methylation, 3T3 L1 preadipocyte cells were differentiated by a hormone cocktail. The genomic DNA was isolated from undifferentiated cells and 4 hours, 2 days postdifferentiated cells, and 15 days TD cells. We employed whole-genome bisulfite sequencing (WGBS) to ascertain global genomic DNA methylation alterations at single base resolution as preadipocyte cells differentiate. The genome-wide distribution of DNA methylation showed similar overall patterns in pre-, post-, and terminally differentiated adipocytes, according to WGBS analysis. DNA methylation decreases at 4 hours after differentiation initiation, followed by methylation gain as cells approach TD. Studies revealed novel differentially methylated regions (DMRs) associated with adipogenesis. DMR analysis suggested that though DNA methylation is global, noticeable changes are observed at specific sites known as "hotspots." Hotspots are genomic regions rich in transcription factor (TF) binding sites and exhibit methylation-dependent TF binding. Subsequent analysis indicated hotspots as part of DMRs. The gene expression profile of key adipogenic genes in differentiating adipocytes is context-dependent, as we found a direct and inverse relationship between promoter DNA methylation and gene expression.

Lactobacillus paracasei subsp. paracasei NTU 101 prevents obesity by regulating AMPK pathways and gut microbiota in obese rat

This study assessed the anti-obesity effects of Lactobacillus paracasei subsp. paracasei NTU 101 (NTU 101) both in vitro and in vivo. Initially, the cytotoxicity and lipid accumulation inhibitory effects of NTU 101 on 3T3-L1 cells were evaluated using the MTT assay and oil red O assay, respectively. Subsequently, the anti-obesity effects of NTU 101 were investigated in high-fat diet-induced obese rat. Moreover, western blotting was performed to measure the obesity-related protein expression of PPARα, PPARβ, PPARγ, C/EBPα, C/EBPβ, ATGL, p-p38 MAPK, p-ERK1/2, p-AMPK and CPT-1 in both 3T3-L1 adipocytes and adipose and liver tissues. Treatment with 16 × 108 CFU/mL NTU 101 reduced lipid accumulation in 3T3-L1 adipocytes by more than 50 %. Oral administration of NTU 101 significantly attenuated body weight gain, as well as adipose tissue weight. NTU 101 administration enhanced fatty acid oxidation increasing expression levels of PPARα, CPT-1, and p-AMPK proteins in liver tissue, while simultaneously inhibited adipogenesis by reducing PPARγ and C/EBPα proteins in adipose tissue. Furthermore, NTU 101 supplementation positively modulated the composition of gut microbiota, notably increasing the abundance of Akkermansiaceae. This present study suggests that NTU 101 exerts anti-obesity effects by regulating gut microbiota, fatty acid oxidation, lipolysis and adipogenesis.

Influence of Seropositivity against Adenovirus-36 on the Risk of Obesity and Insulin Resistance in the Child Population of Southern Chile

Background: Previous infection with Adenovirus-36 (HAdv-D36) has been associated with adipogenesis and glycemic regulation in cell culture and animal models. In humans, HAdv-D36 antibodies correlate with increased obesity risk yet paradoxically enhance glycemic control across various demographics. This study assesses the association of HAdv-D36 seropositivity with obesity, lipid, and glycemic profiles among school-aged children. Methods: We evaluated 208 children aged 9-13, categorized by BMI z-scores into normal weight (-1 to +1), overweight (+1 to +2), and obese (>+3). Assessments included anthropometry, Tanner stage for pubertal development, and biochemical tests (relating to lipids, glucose, and insulin), alongside HAdv-D36 seropositivity checked via ELISA. Insulin resistance was gauged using Chilean pediatric criteria. Results: The cohort displayed a high prevalence of overweight/obesity. HAdv-D36 seropositivity was 5.4%, showing no correlation with nutritional status. Additionally, no link between HAdv-D36 seropositivity and lipid levels was observed. Notably, insulin levels and HOMA-RI were significantly lower in HAdv-D36 positive children (p < 0.001). No cases of insulin resistance were reported in the HAdv-D36 (+) group in our population. Conclusions: HAdv-D36 seropositivity appears to decrease insulin secretion and resistance, aligning with earlier findings. However, no association with obesity development was found in the child population of southern Chile.

Bioactive Peptides from Meretrix lusoria Enzymatic Hydrolysate as a Potential Treatment for Obesity in db/db Mice

Obesity is acknowledged as a significant risk factor for cardiovascular disease, often accompanied by increased inflammation and diabetes. Bioactive peptides derived from marine animal proteins show promise as safe and effective anti-obesity agents by regulating adipocyte differentiation through the AMPK signaling pathway. Therefore, this study aims to investigate the anti-obesity and anti-diabetic effects of bioactive compounds derived from a Meretrix lusoria Protamex enzymatic hydrolysate (MLP) fraction (≤1 kDa) through a 6-week treatment (150 mg/kg or 300 mg/kg, administered once daily) in leptin receptor-deficient db/db mice. The MLP treatment significantly decreased the body weight, serum total cholesterol, triglycerides, and LDL-cholesterol levels while also exhibiting a beneficial effect on hepatic and serum marker parameters in db/db mice. A histological analysis revealed a reduction in hepatic steatosis and epididymal fat following MLP treatment. Furthermore, poor glucose tolerance was improved, and hepatic antioxidant enzyme activities were elevated in MLP-treated mice compared to db/db control mice. Western blot analysis showed an increased expression of the AMPK protein after MLP treatment. In addition, the expression of lipogenic genes decreased in db/db mice. These findings indicate that bioactive peptides, which are known to regulate blood glucose levels, lipid metabolism, and adipogenesis, could be beneficial functional food additives and pharmaceuticals.

White-to-Beige and Back: Adipocyte Conversion and Transcriptional Reprogramming

Obesity has become a pandemic, as currently more than half a billion people worldwide are obese. The etiology of obesity is multifactorial, and combines a contribution of hereditary and behavioral factors, such as nutritional inadequacy, along with the influences of environment and reduced physical activity. Two types of adipose tissue widely known are white and brown. While white adipose tissue functions predominantly as a key energy storage, brown adipose tissue has a greater mass of mitochondria and expresses the uncoupling protein 1 (UCP1) gene, which allows thermogenesis and rapid catabolism. Even though white and brown adipocytes are of different origin, activation of the brown adipocyte differentiation program in white adipose tissue cells forces them to transdifferentiate into "beige" adipocytes, characterized by thermogenesis and intensive lipolysis. Nowadays, researchers in the field of small molecule medicinal chemistry and gene therapy are making efforts to develop new drugs that effectively overcome insulin resistance and counteract obesity. Here, we discuss various aspects of white-to-beige conversion, adipose tissue catabolic re-activation, and non-shivering thermogenesis.

Lipid metabolism regulation by dietary polysaccharides with different structural properties

Lipid metabolism plays an important role in energy homeostasis maintenance in response to stress. Nowadays, hyperlipidemia-related chronic diseases such as obesity, diabetes, atherosclerosis, and fatty liver pose significant health challenges. Dietary polysaccharides (DPs) have gained attention for their effective lipid-lowering properties. This review examines the multifaceted mechanisms that DPs employ to lower lipid levels in subjects with hyperlipidemia. DPs could directly inhibit lipid intake and absorption, promote lipid excretion, and regulate key enzymes involved in lipid metabolism pathways, including triglyceride and cholesterol anabolism and catabolism, fatty acid oxidation, and bile acid synthesis. Additionally, DPs indirectly improve lipid homeostasis by modulating gut microbiota composition and alleviating oxidative stress. Moreover, the lipid-lowering mechanisms of particular structural DPs (including β-glucan, pectin, glucomannan, inulin, arabinoxylan, and fucoidan) are summarized. The relationship between the structure and lipid-lowering activity of DPs is also discussed based on current researches. Finally, potential breakthroughs and future directions in the development of DPs in lipid-lowering activity are discussed. The paper could provide a reference for further exploring the mechanism of DPs for lipid regulations and utilizing DPs as lipid-lowering dietary ingredients.

Targeting Metabolic Syndrome Pathways: Carrot microRNAs As Potential Modulators

Metabolic syndrome is a condition characterized by metabolic alterations that culminate in chronic noncommunicable diseases of high morbidity and mortality, such as cardiovascular diseases, type 2 diabetes, nonalcoholic fatty liver disease, and colon cancer. Developing new therapeutic strategies with a multifactorial approach is important since current therapies focus on only one or two components of the metabolic syndrome. In this sense, plant-based gene regulation represents an innovative strategy to prevent or modulate human metabolic pathologies, including metabolic syndrome. Here, using a computational and systems biology approach, it was found that carrot microRNAs can modulate key BMPs/SMAD signaling members, C/EBPs, and KLFs involved in several aspects associated with metabolic syndrome, including the hsa04350:TGF-beta signaling pathway, hsa04931:insulin resistance, hsa04152:AMPK signaling pathway, hsa04933:AGE-RAGE signaling pathway in diabetic complications, hsa04010:MAPK signaling pathway, hsa04350:TGF-beta signaling pathway, hsa01522:endocrine resistance, and hsa04910:insulin signaling pathway. These data demonstrated the potential applications of carrot microRNAs as effective food-based therapeutics for obesity and associated metabolic diseases.

A review of the role of transcription factors in regulating adipogenesis and lipogenesis in beef cattle

In the past few decades, genomic selection and other refined strategies have been used to increase the growth rate and lean meat production of beef cattle. Nevertheless, the fast growth rates of cattle breeds are often accompanied by a reduction in intramuscular fat (IMF) deposition, impairing meat quality. Transcription factors play vital roles in regulating adipogenesis and lipogenesis in beef cattle. Meanwhile, understanding the role of transcription factors in regulating adipogenesis and lipogenesis in beef cattle has gained significant attention to increase IMF deposition and meat quality. Therefore, the aim of this paper was to provide a comprehensive summary and valuable insight into the complex role of transcription factors in adipogenesis and lipogenesis in beef cattle. This review summarizes the contemporary studies in transcription factors in adipogenesis and lipogenesis, genome-wide analysis of transcription factors, epigenetic regulation of transcription factors, nutritional regulation of transcription factors, metabolic signalling pathways, functional genomics methods, transcriptomic profiling of adipose tissues, transcription factors and meat quality and comparative genomics with other livestock species. In conclusion, transcription factors play a crucial role in promoting adipocyte development and fatty acid biosynthesis in beef cattle. They control adipose tissue formation and metabolism, thereby improving meat quality and maintaining metabolic balance. Understanding the processes by which these transcription factors regulate adipose tissue deposition and lipid metabolism will simplify the development of marbling or IMF composition in beef cattle.

DNA methylation promotes the expression of PPARγ transcript 1 at least in part by preventing NRF1 binding to the promoter P1 of chicken PPARγ gene

Peroxisome proliferator-activated receptor gamma (PPARγ) is a master regulator of adipogenesis. Our previous study revealed that chicken PPARγ has 3 alternative promoters named as P1, P2, and P3, and the DNA methylation of promoter P3 was negatively associated with PPARγ mRNA expression in abdominal adipose tissue (AAT). However, the methylation status of promoters P1 and P2 is unclear. Here we assessed promoter P1 methylation status in AAT of Northeast Agricultural University broiler lines divergently selected for abdominal fat content (NEAUHLF). The results showed that promoter P1 methylation differed in AAT between the lean and fat lines of NEAUHLF at 7 wk of age (p < 0.05), and AAT expression of PPARγ transcript 1 (PPARγ1), which was derived from the promoter P1, was greatly higher in fat line than in lean line at 2 and 7 wk of age. The results of the correlation analysis showed that P1 methylation was positively correlated with PPARγ1 expression at 7 wk of age (Pearson's r = 0.356, p = 0.0242), suggesting P1 methylation promotes PPARγ1 expression. To explore the underlying molecular mechanism of P1 methylation on PPARγ1 expression, bioinformatics analysis, dual-luciferase reporter assay, pyrosequencing, and electrophoresis mobility shift assay (EMSA) were performed. The results showed that transcription factor NRF1 repressed the promoter activity of the unmethylated P1, but not the methylated P1. Of all the 4 CpGs (CpG48, CpG49, CpG50, and CpG51), which reside within or nearby the NRF1 binding sites of the P1, only CpG49 methylation in AAT was remarkably higher in the fat line than in lean line at 7 wk of age (3.18 to 0.57, p < 0.05), and CpG49 methylation was positively correlated with PPARγ1 expression (Pearson's r = 0.3716, p = 0.0432). Furthermore, EMSA showed that CpG49 methylation reduced the binding of NRF1 to the P1. Taken together, our findings illustrate that P1 methylation promotes PPARγ1 expression at least in part by preventing NRF1 from binding to the promoter P1.

Multi-tissue profiling of oxylipins reveal a conserved up-regulation of epoxide:diol ratio that associates with white adipose tissue inflammation and liver steatosis in obesity

BACKGROUND

Obesity drives maladaptive changes in the white adipose tissue (WAT) which can progressively cause insulin resistance, type 2 diabetes mellitus (T2DM) and metabolic dysfunction-associated liver disease (MASLD). Obesity-mediated loss of WAT homeostasis can trigger liver steatosis through dysregulated lipid pathways such as those related to polyunsaturated fatty acid (PUFA)-derived oxylipins. However, the exact relationship between oxylipins and metabolic syndrome remains elusive and cross-tissue dynamics of oxylipins are ill-defined.

METHODS

We quantified PUFA-related oxylipin species in the omental WAT, liver biopsies and plasma of 88 patients undergoing bariatric surgery (female N = 79) and 9 patients (female N = 4) undergoing upper gastrointestinal surgery, using UPLC-MS/MS. We integrated oxylipin abundance with WAT phenotypes (adipogenesis, adipocyte hypertrophy, macrophage infiltration, type I and VI collagen remodelling) and the severity of MASLD (steatosis, inflammation, fibrosis) quantified in each biopsy. The integrative analysis was subjected to (i) adjustment for known risk factors and, (ii) control for potential drug-effects through UPLC-MS/MS analysis of metformin-treated fat explants ex vivo.

FINDINGS

We reveal a generalized down-regulation of cytochrome P450 (CYP)-derived diols during obesity conserved between the WAT and plasma. Notably, epoxide:diol ratio, indicative of soluble epoxide hydrolyse (sEH) activity, increases with WAT inflammation/fibrosis, hepatic steatosis and T2DM. Increased 12,13-EpOME:DiHOME in WAT and liver is a marker of worsening metabolic syndrome in patients with obesity.

INTERPRETATION

These findings suggest a dampened sEH activity and a possible role of fatty acid diols during metabolic syndrome in major metabolic organs such as WAT and liver. They also have implications in view of the clinical trials based on sEH inhibition for metabolic syndrome.

FUNDING

Wellcome Trust (PS3431_WMIH); Duke-NUS (Intramural Goh Cardiovascular Research Award (Duke-NUS-GCR/2022/0020); National Medical Research Council (OFLCG22may-0011); National Institute of Environmental Health Sciences (Z01 ES025034); NIHR Imperial Biomedical Research Centre.

N6-Methyladenosine in Cell-Fate Determination of BMSCs: From Mechanism to Applications

The methylation of adenosine base at the nitrogen-6 position is referred to as "N6-methyladenosine (m6A)" and is one of the most prevalent epigenetic modifications in eukaryotic mRNA and noncoding RNA (ncRNA). Various m6A complex components known as "writers," "erasers," and "readers" are involved in the function of m6A. Numerous studies have demonstrated that m6A plays a crucial role in facilitating communication between different cell types, hence influencing the progression of diverse physiological and pathological phenomena. In recent years, a multitude of functions and molecular pathways linked to m6A have been identified in the osteogenic, adipogenic, and chondrogenic differentiation of bone mesenchymal stem cells (BMSCs). Nevertheless, a comprehensive summary of these findings has yet to be provided. In this review, we primarily examined the m6A alteration of transcripts associated with transcription factors (TFs), as well as other crucial genes and pathways that are involved in the differentiation of BMSCs. Meanwhile, the mutual interactive network between m6A modification, miRNAs, and lncRNAs was intensively elucidated. In the last section, given the beneficial effect of m6A modification in osteogenesis and chondrogenesis of BMSCs, we expounded upon the potential utility of m6A-related therapeutic interventions in the identification and management of human musculoskeletal disorders manifesting bone and cartilage destruction, such as osteoporosis, osteomyelitis, osteoarthritis, and bone defect.

HOXA9 gene inhibits proliferation and differentiation and promotes apoptosis of bovine preadipocytes

BACKGROUND

Hox gene family is an important transcription factor that regulates cell process, and plays a role in the process of adipocytes differentiation and fat deposition. Previous transcriptome sequencing studies have indicated that the Homeobox A9 gene (HOXA9) is a candidate gene for regulating the process of bovine lipid metabolism, but the function and specific mechanism of action remain unclear. Therefore, this study aims to explore the role of HOXA9 in the proliferation, differentiation and apoptosis of bovine preadipocytes through gain-of-function and lose-of-function.

RESULT

It found HOXA9 highly expressed in bovine adipose tissue, and its expression level changed significantly during adipocytes differentiation process. It gave a hint that HOXA9 may be involved in the process of bovine lipid metabolism. The results of HOXA9 gain-of-function experiments indicated that HOXA9 appeared to act as a negative regulator not only in the differentiation but also in the proliferation of bovine preadipocytes, which is mainly reflected that overexpression of HOXA9 down-regulate the mRNA and protein expression level of PPARγ, CEBPα and FABP4 (P < 0.05). The mRNA expression level of CDK1, CDK2, PCNA, CCNA2, CCNB1, CCND1 and CCNE2, as well as the protein expression of CDK2 also significantly decreased. The decrease of lipid droplets content was the main characteristic of the phenotype (P < 0.01), which further supported the evidence that HOXA9 was a negative regulator of preadipocytes differentiation. The decrease of cell proliferation rate and EdU positive rate, as well as the limitation of transition of preadipocytes from G0/G1 phase to S phase also provided evidence for the inhibition of proliferation. Apart from this above, we noted an interesting phenomenon that overexpression of HOXA9 showed in a significant upregulation of both mRNA and protein level of apoptosis markers, accompanied by a significant increase in cell apoptosis rate. These data led us not to refute the fact that HOXA9 played an active regulatory role in apoptosis. HOXA9 loss-of-function experiments, however, yielded the opposite results. Considering that HOXA9 acts as a transcription factor, we predicted its target genes. Dual luciferase reporter assay system indicated that overexpression of HOXA9 inhibits activity of PCNA promoter.

CONCLUSION

Taken together, we demonstrated for the first time that HOXA9 played a role as a negative regulatory factor in the differentiation and proliferation of preadipocytes, but played a positive regulatory role in apoptosis, and it may play a regulatory role by targeting PCNA. This study provides basic data for further exploring the regulatory network of intramuscular fat deposition in bovine.

Silencing ANGPTL8 reduces mouse preadipocyte differentiation and insulin signaling

ANGPTL8, expressed mainly in the liver and adipose tissue, regulates the activity of lipoprotein lipase (LPL) present in the extracellular space and triglyceride (TG) metabolism through its interaction with ANGPTL3 and ANGPTL4. Whether intracellular ANGPTL8 can also exert effects in tissues where it is expressed is uncertain. ANGPTL8 expression was low in preadipocytes and much increased during differentiation. To better understand the role of intracellular ANGPTL8 in adipocytes and assess whether it may play a role in adipocyte differentiation, we knocked down its expression in normal mouse subcutaneous preadipocytes. ANGPTL8 knockdown reduced adipocyte differentiation, cellular TG accumulation and also isoproterenol-stimulated lipolysis at day 7 of differentiation. RNA-Seq analysis of ANGPTL8 siRNA or control siRNA transfected SC preadipocytes on days 0, 2, 4 and 7 of differentiation showed that ANGPTL8 knockdown impeded the early (day 2) expression of adipogenic and insulin signaling genes, PPARγ, as well as genes related to extracellular matrix and NF-κB signaling. Insulin mediated Akt phosphorylation was reduced at an early stage during adipocyte differentiation. This study based on normal primary cells shows that ANGPTL8 has intracellular actions in addition to effects in the extracellular space, like modulating LPL activity. Preadipocyte ANGPTL8 expression modulates their differentiation possibly via changes in insulin signaling gene expression.

Assessing the contribution of plastic-associated obesogenic compounds to cardiometabolic diseases

PURPOSE OF REVIEW

To present recent evidence that strengthens the concept that exogenous pollutants contribute to adipose dysfunction and increased rates of disease and to highlight the ineffective regulation of this risk as industry switches to related but similarly toxic variants.

RECENT FINDINGS

Substitutes for common phthalates and the highly regulated bisphenol A (BPA) show similar deleterious effects on adipocytes. The well tolerated limit for BPA exposure has been reduced in Europe to below the level detected in recent population studies. Additionally, the role for BPA-induced inflammation mediated by interleukin 17a has been described in animal and human studies.

SUMMARY

Despite experimental and associative evidence that supports plastics and plastic associated chemicals deleteriously influencing adipose homeostatasis and contributing to metabolic diseases, structurally related alternate chemicals are being substituted by manufacturers to circumvent trailing regulatory actions.

Cell-state dependent regulation of PPAR γ signaling by ZBTB9 in adipocytes

Adipocytes play a critical role in metabolic homeostasis. Peroxisome proliferator-activated receptor- γ (PPAR γ ) is a nuclear hormone receptor that is a master regulator of adipocyte differentiation and function. ZBTB9 was predicted to interact with PPAR γ based on large-scale protein interaction experiments. In addition, GWAS studies in the type 2 diabetes (T2D) Knowledge Portal revealed associations between Z btb9 and both BMI and T2D risk. Here we show that ZBTB9 positively regulates PPAR γ activity in mature adipocytes. Surprisingly Z btb9 knockdown (KD) also increased adipogenesis in 3T3-L1 cells and human preadipocytes. E2F activity was increased and E2F downstream target genes were upregulated in Zbtb9 -KD preadipocytes. Accordingly, RB phosphorylation, which regulates E2F activity, was enhanced in Zbtb9 -KD preadipocytes. Critically, an E2F1 inhibitor blocked the effects of Zbtb9 deficiency on adipogenic gene expression and lipid accumulation. Collectively, these results demonstrate that Zbtb9 inhibits adipogenesis as a negative regulator of Pparg expression via altered RB-E2F1 signaling. Our findings reveal complex cell-state dependent roles of ZBTB9 in adipocytes, identifying a new molecule that regulates adipogenesis and adipocyte biology as both a positive and negative regulator of PPAR γ signaling depending on the cellular context, and thus may be important in the pathogenesis and treatment of obesity and T2D.

Pennogenin 3-O-β-Chacotrioside Attenuates Hypertrophied Lipid Accumulation by Enhancing Mitochondrial Oxidative Capacity

Excessive lipid accumulation in adipocytes is a primary contributor to the development of metabolic disorders, including obesity. The consumption of bioactive compounds derived from natural sources has been recognized as being safe and effective in preventing and alleviating obesity. Therefore, we aimed to explore the antilipidemic effects of pennogenin 3-O-β-chacotrioside (P3C), a steroid glycoside, on hypertrophied 3T3-L1 adipocytes. Oil Red O and Nile red staining demonstrated a P3C-induced reduction in lipid droplet accumulation. Additionally, the increased expression of adipogenic and lipogenic factors, including PPARγ and C/EBPα, during the differentiation process was significantly decreased by P3C treatment at both the protein and mRNA levels. Furthermore, P3C treatment upregulated the expression of fatty acid oxidation-related genes such as PGC1α and CPT1a. Moreover, mitochondrial respiration and ATP generation increased following P3C treatment, as determined using the Seahorse XF analyzer. P3C treatment also increased the protein expression of mitochondrial oxidative phosphorylation in hypertrophied adipocytes. Our findings suggest that P3C could serve as a natural lipid-lowering agent, reducing lipogenesis and enhancing mitochondrial oxidative capacity. Therefore, P3C may be a promising candidate as a therapeutic agent for obesity-related diseases.

Transcriptional regulatory mechanism of NR2F2 and ZNF423 in avian preadipocyte differentiation

In the poultry industry, excessive abdominal fat deposition is not conducive to meat quality. Therefore, selection for optimal fat content levels in poultry has become a major breeding goal. We previously constructed NR2F2 overexpression (NR2F2OE) and knockout (NR2F2Δ/Δ/83-125aa) cell lines using Piggybac and CRISPR/Cas9 techniques, and confirmed that the transcription factor NR2F2 can significantly inhibit the differentiation of avian preadipocytes. In this study, we identified a downstream gene ZNF423 regulated by NR2F2, which is also involved in regulating avian fat deposition. First, we performed transcriptome analysis of the NR2F2-edited lines, which has been proven to be an inhibitor of avian fat deposition in our previous studies. Our findings revealed that NR2F2 affects a series of candidate regulators related to adipogenesis. Among these, we focused on ZNF423, which was significantly down-regulated in the NR2F2OE cell line and up-regulated in the NR2F2Δ/Δ/83-125aa cell line. Next, dual luciferase reporter assay results showed that the DNA-binding domain (DBDΔ72-143aa) of transcription factor NR2F2 may negatively affect the expression of downstream target gene ZNF423 by binding to its distal promoter region (-2356 to -2346). Moreover, we constructed a function analytical model and found that overexpression of ZNF423 significantly facilitated the differentiation of adipocytes in immortalized chicken preadipocytes (ICP1). Consistent with these findings, global transcriptome analysis of the ZNF423-overexpressed cell line (ZNF423OE) further demonstrated that the process of adipogenesis was significantly enriched. These results indicate that ZNF423 is a positive regulator of avian adipocyte differentiation. Overexpression of ZNF423 in the NR2F2OE cell line compensated for the inhibition of fat deposition phenotype, further suggesting that ZNF423 is a downstream target gene of NR2F2. These findings uncover a novel function of ZNF423 in avian adipocyte differentiation and analyzed the transcriptional regulation by its upstream transcription factor NR2F2. Additionally, we identified a list of functional candidate genes, providing important insights for further research on the mechanism of avian fat deposition.

The inhibitory effects of Xiao-Gao-Jiang-Zhuo-containing serum on adipogenesis in 3T3-L1 preadipocytes

BACKGROUND

Obesity and related metabolic diseases are becoming a worldwide epidemic, leading to increased mortality and heavy medical costs. Our Chinese herbal formula Xiao-Gao-Jiang-Zhuo (XGJZ) has remarkable effects on curing obese patients in the clinic, but the cellular and molecular basis remains unknown. This study aimed to reveal the molecular mechanism involved in adipogenesis in vitro.

METHODS

Chinese herbal formula XGJZ-containing serum was prepared from XGJZ-treated obesity model rats. The function of XGJZ-containing serum was validated in 3T3-L1 preadipocytes. Oil O staining was performed to determine intracellular lipid accumulation in differentiated 3T3-L1 cells. The expression of pro-adipogenic transcription factors was measured to further validate the adipogenesis of 3T3-L1 adipocytes. The contents of triglyceride (TG), free fatty acid (FFA), and glycerin, along with the activities of lipid metabolism-related enzymes (including FAT, FATP1, DGAT, GPAT, ATGL, and HSL) were measured to study the lipogenesis in 3T3-L1 adipocytes.

RESULTS

XGJZ-containing serum inhibited 3T3-L1 differentiation, decreased intracellular lipid accumulation, and suppressed the expression of pro-adipogenic transcription factors in differentiated 3T3-L1 cells. The contents of TG, FFA, and glycerin were decreased when treated with XGJZ-containing serum, which also modulated lipid metabolism-related enzyme activities. The activities of fatty acid transporters (FAT, FATP1) and lipid mobilization enzymes (ATGL, HSL) were promoted, while activities of triglyceride biosynthesis enzymes (DGAT, GPAT) were attenuated in differentiated 3T3-L1 cells.

CONCLUSION

XGJZ-containing serum has inhibitory effects on adipogenesis in 3T3-L1 preadipocytes, affirming the effect of XGJZ in treating obesity. It provides evidence for the mechanism of obesity.

Inference of differential gene regulatory networks using boosted differential trees

Summary

Diseases can be caused by molecular perturbations that induce specific changes in regulatory interactions and their coordinated expression, also referred to as network rewiring. However, the detection of complex changes in regulatory connections remains a challenging task and would benefit from the development of novel nonparametric approaches. We develop a new ensemble method called BoostDiff (boosted differential regression trees) to infer a differential network discriminating between two conditions. BoostDiff builds an adaptively boosted (AdaBoost) ensemble of differential trees with respect to a target condition. To build the differential trees, we propose differential variance improvement as a novel splitting criterion. Variable importance measures derived from the resulting models are used to reflect changes in gene expression predictability and to build the output differential networks. BoostDiff outperforms existing differential network methods on simulated data evaluated in four different complexity settings. We then demonstrate the power of our approach when applied to real transcriptomics data in COVID-19, Crohn's disease, breast cancer, prostate adenocarcinoma, and stress response in Bacillus subtilis. BoostDiff identifies context-specific networks that are enriched with genes of known disease-relevant pathways and complements standard differential expression analyses.

Availability and implementation

BoostDiff is available at https://github.com/scibiome/boostdiff_inference.

Transcriptional modulation of heat shock proteins and adipogenic regulators in bovine adipocytes following heat exposure

This research endeavored to elucidate the transcriptional modulation of heat shock proteins and adipogenic regulators in bovine subcutaneous adipocytes following thermal exposure. Post-differentiation, mature adipocytes were subjected to three treatments of control (CON), moderate (MHS), and extreme (EHS) heat stress. These treatments consist of thermal conditions at temperatures of 38 °C (CON), 39.5 °C (MHS), or 41 °C (EHS) along with of 3 or 12 h. There was no statistically significant variations observed in the gene expressions of HSP27 and HSP70 when comparing CON with MHS across both exposures. Contrastingly, when comparing CON with EHS, an upregulation (P < 0.01) in HSP27 gene expression was evident for both 3 and 12 h of incubation, while HSP70 gene expression exhibited elevation (P < 0.01) at the 3-h mark, with no change observed at 12 h. Protein quantification, however, revealed an elevation (P < 0.01) in HSP27 and HSP70 for both CON vs. MHS and CON vs. EHS at the 12-h exposure. This trend in protein level mirrored (P < 0.05) that of proliferator-activated receptor-gamma (PPARγ). Elevated (P < 0.05) protein levels of fatty acid synthase (FAS) were exclusively discernible in the CON vs. MHS. Increased (P < 0.01) transcriptional activity of PPARγ, CCAAT/enhancer-binding protein alpha (C/EBPα), stearoyl-CoA desaturase (SCD), and FAS was evident in the CON vs. EHS comparison. Complementary to these molecular findings, an augmented lipid droplet accumulation was observed (P < 0.01) in EHS-exposed adipocytes progressively from day 6 through day 9. Our current study highlights how different levels and lengths of heat stress can impact the activity of important heat-related proteins and factors that play a role in fat development in beef cattle. These findings can help guide strategies to manage how beef cattle are exposed to heat, which can affect fat storage and ultimately the quality of the meat's marbling.

Loss of Function of the Retinoblastoma Gene Affects Gap Junctional Intercellular Communication and Cell Fate in Osteoblasts

Loss of function of the Retinoblastoma gene (RB1) due to mutations is commonly seen in human osteosarcomas. One of the Rb1 gene functions is to facilitate cell fate from mesenchymal stem cells to osteoblasts and prevent adipocyte differentiations. In this study, we demonstrate that a stable reduction of Rb1 expression (RbKD) in murine osteoblasts causes them to express higher levels of PPAR-ɣ and other adipocyte-specific transcription factors while retaining high expression of osteoblast-specific transcription factors, Runx2/Cbfa1 and SP7/Osterix. Inhibition of gap junctional intercellular communication (GJIC) in osteoblasts is another mechanism that causes osteoblasts to transdifferentiate to adipocytes. We found that preosteoblasts exposed to osteoblast differentiating media (DP media) increased GJIC. RbKD cells showed reduced GJIC along with a reduction in expression of Cx43, the protein that mediates GJIC. Other membrane associated adhesion protein Cadherin 11 (Cad11) was also decreased. Since PPAR-ɣ is increased with Rb1 loss, we wondered if the reduction of this transcription factor would reverse the changes observed. Reduction of PPAR-ɣ in control osteoblasts slightly increased bone-specific expression and reduced adipocytic expression as expected along with an increase in Cad11 and Cx43 expression. GJIC remained high and was unaffected by a reduction in PPAR-ɣ in control cells. Knockdown of PPAR-ɣ in RbKD cells reduced adipocyte gene expression, while osteoblast-specific expression showed improvement. Cx43, Cad11 and GJIC remained unaffected by PPAR-ɣ reduction. Our observations suggest that increased PPAR-ɣ that happens with Rb1 loss only affects osteoblast-adipocyte-specific gene expression but does not completely reverse Cx43 gene expression or GJIC. Therefore, these effects may represent independent events triggered by Rb1loss and/or the differentiation process.

IGF2BP3-mediated enhanced stability of MYLK represses MSC adipogenesis and alleviates obesity and insulin resistance in HFD mice

Mesenchymal stem cells (MSCs) hold immense potential as multipotent stem cells and serve as a primary source of adipocytes. The process of MSC adipogenesis plays a crucial role in maintaining systemic metabolic homeostasis and has garnered significant attention in tissue bioengineering. N6-methyladenosine (m6A), the most prevalent RNA modification, is known to regulate cell fate and disease. However, the precise involvement of m6A readers in MSC adipogenesis remains unclear. In this study, we investigated the impact of IGF2BP3, a prominent m6A reader, on MSC adipogenesis. Our findings revealed a decrease in IGF2BP3 expression during the natural adipogenic differentiation of MSCs. Furthermore, IGF2BP3 was found to repress MSC adipogenesis by augmenting the levels of MYLK, a calcium/calmodulin-dependent kinase. Mechanistically, IGF2BP3 interacted with MYLK mRNA in an m6A-dependent manner, extending its half-life and subsequently inhibiting the phosphorylation of the ERK1/2 pathway, thereby impeding the adipogenic differentiation of MSCs. Additionally, we successfully achieved the overexpression of IGF2BP3 through intraperitoneal injection of adeno-associated virus serotype Rec2, which specifically targeted adipose tissue. This intervention resulted in reduced body weight and improved insulin resistance in high-fat diet mice. Overall, our study provides novel insights into the role of IGF2BP3 in MSC adipogenesis, shedding light on adipocyte-related disorders and presenting potential targets for related biomedical applications.

Cinnamyl Alcohol Attenuates Adipogenesis in 3T3-L1 Cells by Arresting the Cell Cycle

Cinnamyl alcohol (CA) is an aromatic compound found in several plant-based resources and has been shown to exert anti-inflammatory and anti-microbial activities. However, the anti-adipogenic mechanism of CA has not been sufficiently studied. The present study aimed to investigate the effect and mechanism of CA on the regulation of adipogenesis. As evidenced by Oil Red O staining, Western blotting, and real-time PCR (RT-PCR) analyses, CA treatment (6.25-25 μM) for 8 d significantly inhibited lipid accumulation in a concentration-dependent manner and downregulated adipogenesis-related markers (peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer-binding protein α (C/EBPα), fatty acid binding protein 4 (FABP4), adiponectin, fatty acid synthase (FAS)) in 3-isobutyl-1-methylxanthine, dexamethasone, and insulin(MDI)-treated 3T3-L1 adipocytes. In particular, among the various differentiation stages, the early stage of adipogenesis was critical for the inhibitory effect of CA. Cell cycle analysis using flow cytometry and Western blotting showed that CA effectively inhibited MDI-induced initiation of mitotic clonal expansion (MCE) by arresting the cell cycle in the G0/G1 phase and downregulating the expression of C/EBPβ, C/EBPδ, and cell cycle markers (cyclin D1, cyclin-dependent kinase 6 (CDK6), cyclin E1, CDK2, and cyclin B1). Moreover, AMP-activated protein kinase α (AMPKα), acetyl-CoA carboxylase (ACC), and extracellular signal-regulated kinase 1/2 (ERK1/2), markers of upstream signaling pathways, were phosphorylated during MCE by CA. In conclusion, CA can act as an anti-adipogenic agent by inhibiting the AMPKα and ERK1/2 signaling pathways and the cell cycle and may also act as a potential therapeutic agent for obesity.

Transcriptional Control of Subcutaneous Adipose Tissue by the Transcription Factor CTCF Modulates Heterogeneity in Fat Distribution in Women

Determining the mechanism driving body fat distribution will provide insights into obesity-related health risks. We used functional genomics tools to profile the epigenomic landscape to help infer the differential transcriptional potential of apple- and pear-shaped women's subcutaneous adipose-derived stem cells (ADSCs). We found that CCCTC-binding factor (CTCF) expression and its chromatin binding were increased in ADSCs from pear donors compared to those from apple donors. Interestingly, the pear enriched CTCF binding sites were located predominantly at the active transcription start sites (TSSs) of genes with active histone marks and YY1 motifs and were also associated with pear enriched RNAPII binding. In contrast, apple enriched CTCF binding sites were mainly found at intergenic regions and when identified at TSS, they were enriched with the bivalent chromatin signatures. Altogether, we provide evidence that CTCF plays an important role in differential regulation of subcutaneous ADSCs gene expression and may influence the development of apple vs. pear body shape.

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.

miR136 regulates proliferation and differentiation of small tail han sheep preadipocytes

Low meat performance is the defect of Small Tail Han sheep. Intramuscular fat affects meat quality and largely determined by adipogenesis. In previous study, miR136 was showed one of differentially expressed microRNAs between preadipocytes and mature adipocytes of Small Tail Han sheep but its role in adipogenesis is still not elucidated. Here, we investigated the effect of miR136 on adipogenesis and the underlying mechanism. qPCR data showed that miR136 level increased with preadipocytes proliferation while declined with preadipocytes differentiation. Moreover, miR136 mimics blocked lipid droplet formation, reduced lipid content and triglyceride accumulation while miR136 inhibitor showed the opposite effects, revealing that miR136 promoted preadipocytes proliferation but inhibited preadipocytes differentiation. Bioinformatics and biochemical validation manifested that PPARGC1B was a target of miR136. Furthermore, miR136 mimics decreased PPARγ and C/EBPα expression accompanied by PPARGC1B expression descending. Reverse effects were observed with miR136 inhibitor. Besides, overexpression of miR136 elevated IGF1 expression. Collectively, our data first exhibited a regulatory role of miR136 in adipogenesis, which is promoting preadipocytes proliferation through elevating IGF1 expression while inhibiting preadipocytes differentiation through targeting PPARGC1B and further declined PPARγ and C/EBPα expression. The modulation of PPARGC1B by miR136 may provide a new potential target for increasing intramuscular fat.

Antiadipogenic Effect of Citrus Flavonoids: Evidence from RNA Sequencing Analysis and Activation of AMPK in 3T3-L1 Adipocytes

Citrus fruits are rich in dietary flavonoids and have many health benefits, but their antiadipogenic mechanism of action and their impact on lipid metabolism remain unclear. In this study, we investigated the effect of citrus flavonoids, namely, hesperidin (HES), narirutin (NAR), nobiletin (NOB), sinensetin (SIN), and tangeretin (TAN), on preventing fat cell development by gene expression in 3T3-L1 adipocytes. Among the citrus flavonoids tested, HES and NAR significantly reduced fat storage and triglyceride levels and increased glucose uptake in 3T3-L1 adipocytes. Additionally, HES and NAR treatment increased the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) while reducing the protein expression of 3-hydroxy-3-methylglutaryl CoA reductase (HMGCR). Furthermore, in silico docking revealed that flavonoids activate AMPK. RNA sequencing analysis demonstrated that citrus flavonoids normalized the expression of 40 genes, which were either upregulated by more than 2-fold or downregulated by less than 0.6-fold including Acadv1, Acly, Akr1d1, Awat1, Cyp27a1, Decr1, Dhrs4, Elovl3, Fasn, G6pc, Gba, Hmgcs1, Mogat2, Lrp5, Sptlc3, and Snca to levels comparable to the control group. Altogether, HES and NAR among five citrus flavonoids showed antiadipogenic effects by regulating the expression of specific lipid metabolism genes partially restored to control levels in 3T3-L1 cells.

The combination of Ephedrae herba and coixol from Coicis semen attenuate adiposity via glucocorticoid receptor regulation

The enhanced therapeutic effects and mechanisms of certain herbal combination in various herbal prescriptions are mostly unclear. A combination of two herbs, namely Ephedrae herba (EH) and Coicis semen (CS), has been commonly prescribed for obesity. In our previous work, the combination of EH and CS was studied using network pharmacological approach to predict its pharmacological targets and in vitro experiments to evaluate its efficacy on obesity. Although we demonstrated enhanced anti-adiposity effects of the combination on matured adipocytes, the molecular mechanisms and contributing compounds underlying the effects of EH-CS combination on adiposity or adipogenesis were not fully elucidated. The current study adopted integrated bioinformatics analysis to precisely validate potential targets of EH-CS by screening differentially expressed genes (DEGs) of morbid obesity patients from NCBI gene expression omnibus (GEO). Based on the functional cluster analysis of down-regulated DEGs, the anti-adipogenesis mechanism of EH-CS combination was speculated with KEGG enrichment analysis. Furthermore, we investigated the combinational effects of EH and coixol, or stigmasterol, the two compounds in CS which were expected to have main beneficial effects in metabolic diseases. Moreover, distinct effect of the combination on transcriptional activity of glucocorticoid receptor (GR) was investigated using electrophoretic mobility shift assay (EMSA). The EH-CS combination was predicted to modulate down-regulated genes which are involved in KEGG pathways crucial to metabolic disease in morbidly obese individuals. The combination of EH with CS compounds significantly increased the phosphorylation of acetyl-coA carboxylase (ACC), AMP-activated protein kinase (AMPK), and protein kinase B (AKT) in 3T3-L1 cells and decreased intracellular lipid accumulation. The two CS compounds significantly increased the anti-adipogenesis/lipogenesis effects of EH by inhibiting the gene expression levels. Finally, the combination of EH and coixol inhibited dexamethasone-induced GR translocation to the nucleus and transcriptional binding activity in adipocytes. The combination of EH and CS could be considered a therapeutic strategy for treating metabolic diseases, including obesity.

TET2 is recruited by CREB to promote Cebpb, Cebpa, and Pparg transcription by facilitating hydroxymethylation during adipocyte differentiation

Ten-eleven translocation proteins (TETs) are dioxygenases that convert 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), an important epigenetic mark that regulates gene expression during development and differentiation. Here, we found that the TET2 expression was positively associated with adipogenesis. Further, in vitro and in vivo experiments showed that TET2 deficiency blocked adipogenesis by inhibiting the expression of the key transcription factors CCAAT/enhancer-binding protein beta (C/EBPβ), C/EBPα and peroxisome proliferator-activated receptor gamma (PPARγ). In addition, TET2 promoted 5hmC on the CpG islands (CGIs) of Cebpb, Cebpa and Pparg at the initial time point of their transcription, which requires the cAMP-responsive element-binding protein (CREB). At last, specific knockout of Tet2 in preadipocytes enabled mice to resist obesity and attenuated the obesity-associated insulin resistance. Together, TET2 is recruited by CREB to promote the expression of Cebpb, Cebpa and Pparg via 5hmC during adipogenesis and may be a potential therapeutic target for obesity and insulin resistance.

Studies on the fat mass and obesity-associated (FTO) gene and its impact on obesity-associated diseases

Obesity has become a major health crisis in the past ∼50 years. The fat mass and obesity-associated (FTO) gene, identified by genome-wide association studies (GWAS), was first reported to be positively associated with obesity in humans. Mice with more copies of the FTO gene were observed to be obese, while loss of the gene in mice was found to protect from obesity. Later, FTO was found to encode an m6A RNA demethylase and has a profound effect on many biological and metabolic processes. In this review, we first summarize recent studies that demonstrate the critical roles and regulatory mechanisms of FTO in obesity and metabolic disease. Second, we discuss the ongoing debates concerning the association between FTO polymorphisms and obesity. Third, since several small molecule drugs and micronutrients have been found to regulate metabolic homeostasis through controlling the expression or activity of FTO, we highlight the broad potential of targeting FTO for obesity treatment. Improving our understanding of FTO and the underlying mechanisms may provide new approaches for treating obesity and metabolic diseases.

New insights into transcriptome variation during cattle adipocyte adipogenesis by direct RNA sequencing

We performed direct RNA sequencing (DRS) together with PCR-amplified cDNA long and short read sequencing for cattle adipocyte at different stages. We proved that the DRS was with advantages to avoid artificial transcripts and questionable exitrons. Totally, we obtained 68,124 transcripts with information of alternative splicing, poly (A) length and mRNA modification. The number of transcripts for adipogenesis was expanded by alternative splicing, which lead regulation mechanisms far more complex than ever known. We detected 891 differentially expressed genes (DEGs). However, 62.78% transcripts of DEGs were not significantly differentially expressed, and 248 transcripts showed opposite changing directions with their genes. The poly (A) tail became globally shorter in differentiated adipocyte than in primary adipocyte, and had a weak negative correlation with gene/transcript expression. Moreover, the study of different mRNA modifications implied their potential roles in gene expression and alternative splicing. Overall, our study promoted better understanding of adipogenesis mechanisms in cattle adipocytes.

Tibetan tea reduces obesity brought on by a high-fat diet and modulates gut flora in mice

It has been shown that Tibetan tea (TT) inhibits obesity and controls lipid metabolism. The fundamental processes by which TT prevents obesity are yet entirely unknown. Consequently, this research aimed to ascertain if TT may prevent obesity by modifying the gut flora. Our research demonstrated that TT prevented mice from gaining weight and accumulating fat due to the high-fat diet (HFD), decreased levels of blood total cholesterol (TC), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C), and raised levels of high-density lipoprotein cholesterol (HDL-C). Adipogenesis-related genes such as acetyl-Coenzyme A carboxylase 1 (ACC1, LOC107476), fatty acid synthase (Fas, LOC14104), sterol regulatory element-binding protein-1c (SREBP-1c, LOC20787), CCAAT/enhancer-binding protein α (C/EBPα, LOC12606), stearoyl-CoA desaturase 1 (SCD1, LOC20249), and peroxisome proliferator-activated receptor γ (PPARγ, LOC19016) had their expression downregulated by lowering the Firmicutes/Bacteroidetes (F/B) ratio and controlling the number of certain gut bacteria. TT also alleviated HFD-induced abnormalities of the gut microbiota. The Muribaculaceae, Lachnospiraceae NK4A136_group, Alistipes, and Odoribacter families were identified as the major beneficial gut microorganisms using Spearman's correlation analysis. Fecal microbiota transplantation (FMT) demonstrated that TT's anti-obesity and gut microbiota-modulating benefits might be transmitted to mice on an HFD, demonstrating that one of TT's targets for preventing obesity is the gut microbiota. TT also increased the amount of short-chain fatty acids (SCFAs) in the feces, including acetic, propionic, and butyric acids. These results indicate the possible development of TT as a prebiotic to combat obesity and associated disorders. These results suggest that TT may act as a prebiotic against obesity and its associated diseases.

Bioinformatics Analysis of miR-181a and Its Role in Adipogenesis, Obesity, and Lipid Metabolism Through Review of Literature

The miRNAs regulate various biological processes in the mammalian body system. The role of miR-181a in the development, progression, and expansion of cancers is well-documented. However, the role of miR-181a in adipogenesis; lipid metabolism; obesity; and obesity-related issues such as diabetes mellitus needs to be explored. Therefore, in the present study, the literature was searched and bioinformatics tools were applied to explore the role of miR-181a in adipogenesis. The list of adipogenic and lipogenic target genes validated through different publications were extracted and compiled. The network and functional analysis of these target genes was performed through in-silico analysis. The mature sequence of miR-181a of different species were extracted from and were found highly conserved among the curated species. Additionally, we also used various bioinformatics tools such as target gene extraction from Targetscan, miRWalk, and miRDB, and the list of the target genes from these different databases was compared, and common target genes were predicted. These common target genes were further subjected to the enrichment score and KEGG pathways analysis. The enrichment score of the vital KEGG pathways of the target genes is the key regulator of adipogenesis, lipogenesis, obesity, and obesity-related syndromes in adipose tissues. Therefore, the information presented in the current review will explore the regulatory roles of miR-181a in fat tissues and its associated functions and manifestations.

Loss of Notch signaling in skeletal stem cells enhances bone formation with aging

Skeletal stem and progenitor cells (SSPCs) perform bone maintenance and repair. With age, they produce fewer osteoblasts and more adipocytes leading to a loss of skeletal integrity. The molecular mechanisms that underlie this detrimental transformation are largely unknown. Single-cell RNA sequencing revealed that Notch signaling becomes elevated in SSPCs during aging. To examine the role of increased Notch activity, we deleted Nicastrin, an essential Notch pathway component, in SSPCs in vivo. Middle-aged conditional knockout mice displayed elevated SSPC osteo-lineage gene expression, increased trabecular bone mass, reduced bone marrow adiposity, and enhanced bone repair. Thus, Notch regulates SSPC cell fate decisions, and moderating Notch signaling ameliorates the skeletal aging phenotype, increasing bone mass even beyond that of young mice. Finally, we identified the transcription factor Ebf3 as a downstream mediator of Notch signaling in SSPCs that is dysregulated with aging, highlighting it as a promising therapeutic target to rejuvenate the aged skeleton.

Characteristics of Human Nasal Turbinate Stem Cells under Hypoxic Conditions

This study investigated the influence of hypoxic culture conditions on human nasal inferior turbinate-derived stem cells (hNTSCs), a subtype of mesenchymal stem cells (MSCs). It aimed to discern how hypoxia affected hNTSC characteristics, proliferation, and differentiation potential compared to hNTSCs cultured under normal oxygen levels. After obtaining hNTSCs from five patients, the samples were divided into hypoxic and normoxic groups. The investigation utilized fluorescence-activated cell sorting (FACS) for surface marker analysis, cell counting kit-8 assays for proliferation assessment, and multiplex immunoassays for cytokine secretion study. Differentiation potential-osteogenic, chondrogenic, and adipogenic-was evaluated via histological examination and gene expression analysis. Results indicated that hNTSCs under hypoxic conditions preserved their characteristic MSC phenotype, as confirmed by FACS analysis demonstrating the absence of hematopoietic markers and presence of MSC markers. Proliferation of hNTSCs remained unaffected by hypoxia. Cytokine expression showed similarity between hypoxic and normoxic groups throughout cultivation. Nevertheless, hypoxic conditions reduced the osteogenic and promoted adipogenic differentiation potential, while chondrogenic differentiation was relatively unchanged. These insights contribute to understanding hNTSC behavior in hypoxic environments, advancing the development of protocols for stem cell therapies and tissue engineering.

Excessive Gestational Weight Gain Alters DNA Methylation and Influences Foetal and Neonatal Body Composition

BACKGROUND

Changes in body weight are associated with the regulation of DNA methylation (DNAm). In this study, we investigated the associations between maternal gestational weight gain-related DNAm and foetal and neonatal body composition.

METHODS

Brazilian pregnant women from the Araraquara Cohort Study were followed up during pregnancy, delivery, and after hospital discharge. Women with normal pre-pregnancy BMI were allocated into two groups: adequate gestational weight gain (AGWG, n = 45) and excessive gestational weight gain (EGWG, n = 30). Foetal and neonatal body composition was evaluated via ultrasound and plethysmography, respectively. DNAm was assessed in maternal blood using Illumina Infinium MethylationEPIC BeadChip arrays. Linear regression models were used to explore the associations between DNAm and foetal and neonatal body composition.

RESULTS

Maternal weight, GWG, neonatal weight, and fat mass were higher in the EGWG group. Analysis of DNAm identified 46 differentially methylated positions and 11 differentially methylated regions (DMRs) between the EGWG and AGWG groups. Nine human phenotypes were enriched for these 11 DMRs located in 13 genes (EMILIN1, HOXA5, CPT1B, CLDN9, ZFP57, BRCA1, POU5F1, ANKRD33, HLA-B, RANBP17, ZMYND11, DIP2C, TMEM232), highlighting the terms insulin resistance, and hyperglycaemia. Maternal DNAm was associated with foetal total thigh and arm tissues and subcutaneous thigh and arm fat, as well as with neonatal fat mass percentage and fat mass.

CONCLUSION

The methylation pattern in the EGWG group indicated a risk for developing chronic diseases and involvement of maternal DNAm in foetal lean and fat mass and in neonatal fat mass.

Prenatal airborne polycyclic aromatic hydrocarbon exposure, altered regulation of peroxisome proliferator-activated receptor gamma (Ppar)γ, and links with mammary cancer

Environmental exposure to polycyclic aromatic hydrocarbons (PAH) has been shown to be associated with chronic disease outcomes through multiple mechanisms including altered regulation of the transcription factor peroxisome proliferator-activated receptor gamma (Ppar) γ. Because PAH exposure and Pparγ each have been associated with mammary cancer, we asked whether PAH would induce altered regulation of Pparγ in mammary tissue, and whether this association may underlie the association between PAH and mammary cancer. Pregnant mice were exposed to aerosolized PAH at proportions that mimic equivalent human exposures in New York City air. We hypothesized that prenatal PAH exposure would alter Pparγ DNA methylation and gene expression and induce the epithelial to mesenchymal transition (EMT) in mammary tissue of offspring (F1) and grandoffspring (F2) mice. We also hypothesized that altered regulation of Pparγ in mammary tissue would associate with biomarkers of EMT, and examined associations with whole body weight. We found that prenatal PAH exposure lowered Pparγ mammary tissue methylation among grandoffspring mice at postnatal day (PND) 28. However, PAH exposure did not associate with altered Pparγ gene expression or consistently with biomarkers of EMT. Finally, lower Pparγ methylation, but not gene expression, was associated with higher body weight among offspring and grandoffspring mice at PND28 and PND60. Findings suggest additional evidence of multi-generational adverse epigenetic effects of prenatal PAH exposure among grandoffspring mice.

Euscaphis japonica Kanitz Fruit Exerts Antiobesity Effects by Inhibiting the Early Stage of Adipogenic Differentiation

During the worldwide COVID-19 outbreak, there was an increase in the prevalence of obesity, including childhood obesity, due to which the awareness of obesity and interest in treatment increased. Accordingly, we describe EJF (Euscaphis japonica Kanitz fruit) extract as a candidate for naturally derived antiobesity agents. In this study, we found that EJF is involved in the early stage of adipogenic differentiation in vitro and finally inhibits adipogenesis. We propose two mechanisms for the antiobesity effect of EJF. First, EJF inhibits MDI-induced mitotic clonal expansion (MCE) by inducing cell cycle arrest at the initiation of adipogenic differentiation. The second aims to regulate stability and activation at the protein level of IRS1, which initiates differentiation in the early stage of differentiation. As a result, it was found that the activation of Akt decreased, leading to the inhibition of the expression of adipogenesis-related transcription factors (PPARγ, C/EBPα) and the subsequent suppression of adipogenic differentiation. In summary, we suggest that EJF can inhibit adipogenesis and lipid accumulation by suppressing the early stage of adipogenic differentiation in 3T3-L1 adipocytes. These findings indicate that EJF's functionality could be beneficial in the treatment of obesity, particularly childhood obesity associated with adipocyte hyperplasia.

Crucial role of iron in epigenetic rewriting during adipocyte differentiation mediated by JMJD1A and TET2 activity

Iron metabolism is closely associated with the pathogenesis of obesity. However, the mechanism of the iron-dependent regulation of adipocyte differentiation remains unclear. Here, we show that iron is essential for rewriting of epigenetic marks during adipocyte differentiation. Iron supply through lysosome-mediated ferritinophagy was found to be crucial during the early stage of adipocyte differentiation, and iron deficiency during this period suppressed subsequent terminal differentiation. This was associated with demethylation of both repressive histone marks and DNA in the genomic regions of adipocyte differentiation-associated genes, 　including Pparg, which encodes PPARγ, the master regulator of adipocyte differentiation. In addition, we identified several epigenetic demethylases to be responsible for iron-dependent adipocyte differentiation, with the histone demethylase jumonji domain-containing 1A and the DNA demethylase ten-eleven translocation 2 as the major enzymes. The interrelationship between repressive histone marks and DNA methylation was indicated by an integrated genome-wide association analysis, and was also supported by the findings that both histone and DNA demethylation were suppressed by either the inhibition of lysosomal ferritin flux or the knockdown of iron chaperone poly(rC)-binding protein 2. In summary, epigenetic regulations through iron-dependent control of epigenetic enzyme activities play an important role in the organized gene expression mechanisms of adipogenesis.

Plant-Derived Nutraceuticals Involved in Body Weight Control by Modulating Gene Expression

Obesity is the most prevalent health problem in the Western world, with pathological body weight gain associated with numerous co-morbidities that can be the main cause of death. There are several factors that can contribute to the development of obesity, such as diet, sedentary lifestyle, and genetic make-up. Genetic predispositions play an important role in obesity, but genetic variations alone cannot fully explain the explosion of obesity, which is why studies have turned to epigenetics. The latest scientific evidence suggests that both genetics and environmental factors contribute to the rise in obesity. Certain variables, such as diet and exercise, have the ability to alter gene expression without affecting the DNA sequence, a phenomenon known as epigenetics. Epigenetic changes are reversible, and reversibility makes these changes attractive targets for therapeutic interventions. While anti-obesity drugs have been proposed to this end in recent decades, their numerous side effects make them not very attractive. On the other hand, the use of nutraceuticals for weight loss is increasing, and studies have shown that some of these products, such as resveratrol, curcumin, epigallocatechin-3-gallate, ginger, capsaicin, and caffeine, can alter gene expression, restoring the normal epigenetic profile and aiding weight loss.

An Evaluation of the Anti-Inflammatory Effects of a Thai Traditional Polyherbal Recipe TPDM6315 in LPS-Induced RAW264.7 Macrophages and TNF-α-Induced 3T3-L1 Adipocytes

TPDM6315 is an antipyretic Thai herbal recipe that contains several herbs with anti-inflammatory and anti-obesity activities. This study aimed to investigate the anti-inflammatory effects of TPDM6315 extracts in lipopolysaccharide (LPS)-induced RAW264.7 macrophages and TNF-α-induced 3T3-L1 adipocytes, and the effects of TPDM6315 extracts on lipid accumulation in 3T3-L1 adipocytes. The results showed that the TPDM6315 extracts reduced the nitric oxide production and downregulated the iNOS, IL-6, PGE₂, and TNF-α genes regulating fever in LPS-stimulated RAW264.7 macrophages. The treatment of 3T3-L1 pre-adipocytes with TPDM6315 extracts during a differentiation to the adipocytes resulted in the decreasing of the cellular lipid accumulation in adipocytes. The ethanolic extract (10 µg/mL) increased the mRNA level of adiponectin (the anti-inflammatory adipokine) and upregulated the PPAR-γ in the TNF-α induced adipocytes. These findings provide evidence-based support for the traditional use of TPDM6315 as an anti-pyretic for fever originating from inflammation. The anti-obesity and anti-inflammatory actions of TPDM6315 in TNF-α induced adipocytes suggest that this herbal recipe could be useful for the treatment of metabolic syndrome disorders caused by obesity. Further investigations into the modes of action of TPDM6315 are needed for developing health products to prevent or regulate disorders resulting from inflammation.

Discovery of new tetrahydroisoquinolines as potent and selective LSD1 inhibitors for the treatment of MLL-rearranged leukemia

Histone lysine-specific demethylase 1 (LSD1) is a promising target for cancer therapy. Here, we performed the design, synthesis, and extensive structure-activity relationship (SAR) studies based on our previously discovered natural LSD1 inhibitor, higenamine. We found that the tetracyclic tetrahydroisoquinoline FY-21 is a potent and selective inhibitor of LSD1 (IC₅₀ = 340 nM). FY-21 inhibited leukemia cell proliferation and colony formation and increased the level of p53 expression. Meanwhile, FY-21 reduced the mRNA levels of the transcription factors HOXA9 and MEIS1. Furthermore, FY-21 significantly induced leukemia cell differentiation. In vivo studies showed that FY-21 prolonged the survival rate of leukemia mice. Collectively, FY-21 is a potent, selective LSD1 inhibitor and can serve as a lead compound for the development of novel and highly effective LSD1 inhibitors for AML treatment.

Epigenetic Histone Methylation of PPARγ and CPT1A Signaling Contributes to Betahistine Preventing Olanzapine-Induced Dyslipidemia

As a partial histamine H1 receptor agonist and H3 antagonist, betahistine has been reported to partially prevent olanzapine-induced dyslipidemia and obesity through a combination therapy, although the underlying epigenetic mechanisms are still not known. Recent studies have revealed that histone regulation of key genes for lipogenesis and adipogenesis in the liver is one of the crucial mechanisms for olanzapine-induced metabolic disorders. This study investigated the role of epigenetic histone regulation in betahistine co-treatment preventing dyslipidemia and fatty liver caused by chronic olanzapine treatment in a rat model. In addition to abnormal lipid metabolism, the upregulation of peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein (C/EBPα), as well as the downregulation of carnitine palmitoyltransferase 1A (CPT1A) in the liver induced by olanzapine, were significantly attenuated by betahistine co-treatment. In addition, betahistine co-treatment significantly enhanced the global expression of H3K4me and the enrichment of H3K4me binding on the promoter of Cpt1a gene as revealed by ChIP-qPCR, but inhibited the expression of one of its site-specific demethylases, lysine (K)-specific demethylase 1A (KDM1A). Betahistine co-treatment also significantly enhanced the global expression of H3K9me and the enrichment of H3K9me binding on the promoter of the Pparg gene, but inhibited the expression of two of its site-specific demethylases, lysine demethylase 4B (KDM4B) and PHD finger protein 2 (PHF2). These results suggest that betahistine attenuates abnormal adipogenesis and lipogenesis triggered by olanzapine through modulating hepatic histone methylation, and thus inhibiting the PPARγ pathway-mediated lipid storage, while at the same time promoting CP1A-mediated fatty acid oxidation.

A novel candidate gene CLN8 regulates fat deposition in avian

BACKGROUND

The fat deposition has a crucial role in animal meat flavor, and fat deposition-related traits are vital for breeding in the commercial duck industry. Avian fat-related traits are typical complex phenotypes, which need a large amount of data to analyze the genetic loci.

RESULTS

In this study, we performed a new phenotypic analysis of fat traits and genotyped whole-genome variations for 1,246 ducks, and combed with previous GWAS data to reach 1,880 ducks for following analysis. The carcass composition traits, subcutaneous fat weight (SFW), subcutaneous fat percentage (SFP), abdominal fat weight (AFW), abdominal fat percentage (AFP) and the body weight of day 42 (BW42) for each duck were collected. We identified a set of new loci that affect the traits related to fat deposition in avian. Among these loci, ceroid-lipofuscinosis, neuronal 8 (CLN8) is a novel candidate gene controlling fat deposition. We investigated its novel function and regulation in avian adipogenesis. Five significant SNPs (the most significant SNP, P-value = 21.37E-12) and a single haplotype were detected in the upstream of CLN8 for subcutaneous fat percentage. Subsequently, luciferase assay demonstrated that 5 linked SNPs in the upstream of the CLN8 gene significantly decreased the transcriptional activity of CLN8. Further, ATAC-seq analysis showed that transcription factor binding sites were identified in a region close to the haplotype. A set of luciferase reporter gene vectors that contained different deletion fragments of the CLN8 promoter were constructed, and the core promoter area of CLN8 was finally identified in the -1,884/-1,207 bp region of the 5' flanking sequences, which contains adipogenesis-related transcription factors binding sites. Moreover, the over-expression of CLN8 can remarkably facilitate adipocyte differentiation in ICPs. Consistent with these, the global transcriptome profiling and functional analysis of the over-expressed CLN8 in the cell line further revealed that the lipid biosynthetic process during the adipogenesis was significantly enriched.

CONCLUSIONS

Our results demonstrated that CLN8 is a positive regulator of avian adipocyte differentiation. These findings identify a novel function of CLN8 in adipocyte differentiation, which provides important clues for the further study of the mechanism of avian fat deposition.

CircADAMTS16 Inhibits Differentiation and Promotes Proliferation of Bovine Adipocytes by Targeting miR-10167-3p

Circular RNAs (CircRNAs) are covalently closed-loop non-coding RNA (ncRNA) molecules present in eukaryotes. Numerous studies have demonstrated that circRNAs are important regulators of bovine fat deposition, but their precise mechanisms remain unclear. Previous transcriptome sequencing studies have indicated that circADAMTS16, a circRNA derived from the a disintegrin-like metalloproteinases with the thrombospondin motif 16 (ADAMTS16) gene, is high expressed in bovine adipose tissue. This gives a hint that the circRNA may be involved in the process of bovine lipid metabolism. In this study, the targeting relationship between circADAMTS16 and miR-10167-3p was verified using a dual-luciferase reporter assay. Then, the functions of circADAMTS16 and miR-10167-3p in bovine adipocytes were explored through gain-of-function and lose-of-function. The mRNA expression levels of genes were detected by real-time quantitative PCR (qPCR), and lipid droplet formation was phenotypically evaluated by Oil Red O staining. Cell proliferation and apoptosis were detected using CCK-8, EdU, and flow cytometry. We demonstrated that circADAMTS16 targeted binding to miR-10167-3p. The up-regulation of circADAMTS16 inhibited the differentiation of bovine preadipocytes, and the overexpression of miR-10167-3p promoted the differentiation of bovine preadipocytes. Meanwhile, CCK-8 and EdU results indicated that circADAMTS16 promoted adipocyte proliferation. Subsequently, flow cytometry analysis showed that circADAMTS16 promoted cell transition from G0/G1 phase to S phase, and inhibited cell apoptosis. However, up-regulation of miR-10167-3p inhibited cell proliferation and promoted apoptosis. Briefly, circADAMTS16 inhibited the differentiation and promotes the proliferation of bovine adipocytes by targeting miR-10167-3p during bovine fat deposition, which provides new insights into the mechanism of circRNAs regulation of beef quality.

A nonsteroidal anti-inflammatory drug, zaltoprofen, inhibits the growth of extraskeletal chondrosarcoma cells by inducing PPARγ, p21, p27, and p53

Peroxisome proliferator-activated receptor gamma (PPARγ) is a nuclear receptor and master transcription factor of adipogenesis-related genes, and has been reported as an antitumor target for chondrosarcomas. Herein, we show that the nonsteroidal anti-inflammatory drug, zaltoprofen, induces the expression of PPARγ at the mRNA and protein levels, following the induction of PPARγ-activating factors, such as Krox20, C/EBPβ, and C/EBPα, in human extraskeletal chondrosarcoma H-EMC-SS cells. Upregulation of the cell cycle checkpoint proteins, p21, p27, and p53, was observed upon treatment of H-EMC-SS cells with zaltoprofen, which probably resulted in the inhibition of proliferation of these cells observed in vitro. Zaltoprofen treatment inhibited tumor growth, induced tumor cell apoptosis, and was well tolerated in a mouse model of extraskeletal myxoid chondrosarcoma. Our results provide mechanistic insights into the therapeutic effect of zaltoprofen that should promote further studies on the rational use of this drug for the effective treatment of sarcomas.