The Anti-Obesogenic Effects of Muscadine Grapes through Ciliary Neurotrophic Factor Receptor (Cntfr) and Histamine Receptor H1 (Hrh1) Genes in 3T3-L1 Differentiated Mouse Cells.

Obesity and type 2 diabetes are prevalent metabolic diseases that have significant links to several chronic diseases, including cancer, diabetes, hypertension, and cardiovascular disease. Muscadine grape extracts have shown the potential to reduce adiposity and improve insulin sensitivity and glucose control. Thus, this study was designed to determine the potential of muscadine grape berries extract (Pineapple and Southern Home) for its antiobesity properties in 3T3-L1 cells as a model for obesity research. The current study's data indicated the total phenolic content (TPC) and 2,2-diphenyl-1-picrylhydraziyl (DPPH) activity were higher in cultivar (CV) Southern Home, meanwhile, elevated the total flavonoid content (TFC) in Pineapple. Both extracts were safe across the tested range (0-5 mg/mL). A noticeable reduction in lipid accumulation was also found in extract-treated cells. In preadipocytes and adipocytes, the tested extracts showed significant alterations in various genes involved in glucose homeostasis and obesity. The most remarkable findings of the current study are the upregulation of two genes, Cntfr (+712.715-fold) and Hrh1 (+270.11-fold) in CV Pineapple extract-treated adipocytes 3T3-L1 and the high fold increase in Ramp3 induced by both Pineapple and Southern Home in pre-adipose cells. Furthermore, the tested extracts showed a potential to alter the mRNA of various genes, including Zfp91, B2m, Nr3c1, Insr, Atrn, Il6ra, Hsp90ab1, Sort1, and Npy1r. In conclusion, the data generated from the current study suggested that the two extracts under investigation are considered potential candidates for controlling insulin levels and managing obesity.

Role of Corn Peptide Powder in Lipopolysaccharide-Induced Inflammatory Responses in 3T3-L1 Adipocytes.

Corn peptide (CP) is a short, naturally occurring, and physiologically active peptide generated from corn-protease-catalyzed hydrolysis. CP plays a role in preventing obesity-related disorders, but its impact on reducing inflammation is unknown. Hence, this study examined the possible protective effects of corn peptide powder (CPP) against the harmful effects of lipopolysaccharide (LPS), with a particular emphasis on reducing oxidative damage and inflammation in adipocytes. Hence, mature 3T3-L1 adipocytes underwent exposure to 10 ng/mL LPS, with or without CPP (10 and 20 µg/mL). LPS stimulation increased reactive oxygen species and superoxide anion generation. However, this effect was reduced in a dose-dependent manner by pretreatment with CPP. CPP treatment elevated the mRNA expressions of the antioxidant enzymes manganese superoxide dismutase (mnSOD) and glutathione peroxidase 1 (Gpx1) while reducing the mRNA expressions of the cytosolic reactive oxygen species indicators p40 and p67 (NADPH oxidase 2). In addition, CPP inhibited the monocyte chemoattractant protein-1, tumor necrosis factor-alpha, Toll-like receptor 4, and nuclear factor kappa B mRNA expressions induced by LPS. These findings demonstrate that CPP may ameliorate adipocyte dysfunction by suppressing oxidative damage and inflammatory responses through a new mechanism known as Toll-like receptor 4/nuclear factor kappa B-mediated signaling.

Myeloid-derived miR-6236 potentiates adipocyte insulin signaling and prevents hyperglycemia during obesity.

Adipose tissue macrophages (ATMs) influence obesity-associated metabolic dysfunction, but the mechanisms by which they do so are not well understood. We show that miR-6236 is a bona fide miRNA that is secreted by ATMs during obesity. Global or myeloid cell-specific deletion of miR-6236 aggravates obesity-associated adipose tissue insulin resistance, hyperglycemia, hyperinsulinemia, and hyperlipidemia. miR-6236 augments adipocyte insulin sensitivity by inhibiting translation of negative regulators of insulin signaling, including PTEN. The human genome harbors a miR-6236 homolog that is highly expressed in the serum and adipose tissue of obese people. hsa-MIR-6236 expression negatively correlates with hyperglycemia and glucose intolerance, and positively correlates with insulin sensitivity. Together, our findings establish miR-6236 as an ATM-secreted miRNA that potentiates adipocyte insulin signaling and protects against metabolic dysfunction during obesity.

Preliminary Single-Cell RNA-Sequencing Analysis Uncovers Adipocyte Heterogeneity in Lipedema.

Background: Despite its increasing incidence and prevalence throughout Western countries, lipedema continues to be a very enigmatic disease, often misunderstood or misdiagnosed by the medical community and with an intrinsic pathology that is difficult to trace. The nature of lipedemic tissue is one of hypertrophic adipocytes and poor tissue turnover. So far, there are no identified pathways responsible, and little is known about the cell populations of lipedemic fat. Methods: Adipose tissue samples were collected from affected areas of both lipedema and healthy participants. For single-cell RNA sequencing analysis, the samples were dissociated into single-cell suspensions using enzymatic digestion and then encapsulated into nanoliter-sized droplets containing barcoded beads. Within each droplet, cellular mRNA was converted into complementary DNA. Complementary DNA molecules were then amplified for downstream analysis. Results: The single-cell RNA-sequencing analysis revealed three distinct adipocyte populations at play in lipedema. These populations have unique gene signatures which can be characterized as a lipid generating adipocyte, a disease catalyst adipocyte, and a lipedemic adipocyte. Conclusions: The single-cell RNA sequencing of lipedemic tissue samples highlights a triad of distinct adipocyte subpopulations, each characterized by unique gene signatures and functional roles. The interplay between these adipocyte subtypes offers promising insights into the complex pathophysiology of lipedema.

The Concept of Stroma AReactive Invasion Front Areas (SARIFA) as a new prognostic biomarker for lipid-driven cancers holds true in pancreatic ductal adenocarcinoma.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a 'difficult-to-treat' entity. To forecast its prognosis, we introduced a new biomarker, SARIFA (stroma areactive invasion front areas), which are areas at the tumour invasion front lacking desmoplastic stroma reaction upon malignant invasion in the surrounding tissue, leading to direct contact between tumour cells and adipocytes. SARIFA showed its significance in gastric and colorectal carcinoma, revealing lipid metabolism alternations that promote tumour progression. METHODS: We reviewed the SARIFA status of 166 PDAC cases on all available H&E-stained tumour slides from archival Whipple-resection specimens. SARIFA positivity was defined as SARIFA detection in at least 66% of the available slides. To investigate alterations in tumour metabolism and microenvironment, we performed immunohistochemical staining for FABP4, CD36 and CD68. To verify and quantify a supposed delipidation of adipocytes, adipose tissue was digitally morphometrised. RESULTS: In total, 53 cases (32%) were classified as SARIFA positive and 113 (68%) as SARIFA negative. Patients with SARIFA-positive PDAC showed a significantly worse overall survival compared with SARIFA-negative cases (median overall survival: 11.0 months vs. 22.0 months, HR: 1.570 (1.082-2.278), 95% CI, p = 0.018), which was independent from other prognostic markers (p = 0.014). At the invasion front of SARIFA-positive PDAC, we observed significantly higher expression of FABP4 (p < 0.0001) and higher concentrations of CD68+ macrophages (p = 0.031) related to a higher risk of tumour progression. CD36 staining showed no significant expression differences. The adipocyte areas at the invasion front were significantly smaller, with mean values of 4021 ± 1058 µm2 and 1812 ± 1008 µm2 for the SARIFA-negative and -positive cases, respectively (p < 0.001). CONCLUSIONS: SARIFA is a promising prognostic biomarker for PDAC. Its assessment is characterised by simplicity and low effort. The mechanisms behind SARIFA suggest a tumour-promoting increased lipid metabolism and altered immune background, both showing new therapeutic avenues.

Adipocyte Mitochondria: Deciphering Energetic Functions across Fat Depots in Obesity and Type 2 Diabetes.

Adipose tissue, a central player in energy balance, exhibits significant metabolic flexibility that is often compromised in obesity and type 2 diabetes (T2D). Mitochondrial dysfunction within adipocytes leads to inefficient lipid handling and increased oxidative stress, which together promote systemic metabolic disruptions central to obesity and its complications. This review explores the pivotal role that mitochondria play in altering the metabolic functions of the primary adipocyte types, white, brown, and beige, within the context of obesity and T2D. Specifically, in white adipocytes, these dysfunctions contribute to impaired lipid processing and an increased burden of oxidative stress, worsening metabolic disturbances. Conversely, compromised mitochondrial function undermines their thermogenic capabilities, reducing the capacity for optimal energy expenditure in brown adipocytes. Beige adipocytes uniquely combine the functional properties of white and brown adipocytes, maintaining morphological similarities to white adipocytes while possessing the capability to transform into mitochondria-rich, energy-burning cells under appropriate stimuli. Each type of adipocyte displays unique metabolic characteristics, governed by the mitochondrial dynamics specific to each cell type. These distinct mitochondrial metabolic phenotypes are regulated by specialized networks comprising transcription factors, co-activators, and enzymes, which together ensure the precise control of cellular energy processes. Strong evidence has shown impaired adipocyte mitochondrial metabolism and faulty upstream regulators in a causal relationship with obesity-induced T2D. Targeted interventions aimed at improving mitochondrial function in adipocytes offer a promising therapeutic avenue for enhancing systemic macronutrient oxidation, thereby potentially mitigating obesity. Advances in understanding mitochondrial function within adipocytes underscore a pivotal shift in approach to combating obesity and associated comorbidities. Reigniting the burning of calories in adipose tissues, and other important metabolic organs such as the muscle and liver, is crucial given the extensive role of adipose tissue in energy storage and release.

TNF-α/Stearate Induced H3K9/18 Histone Acetylation Amplifies IL-6 Expression in 3T3-L1 Mouse Adipocytes.

Extensive evidence supports the connection between obesity-induced inflammation and the heightened expression of IL-6 adipose tissues. However, the mechanism underlying the IL-6 exacerbation in the adipose tissue remains unclear. There is general agreement that TNF-α and stearate concentrations are mildly elevated in adipose tissue in the state of obesity. We hypothesize that TNF-α and stearate co-treatment induce the increased expression of IL-6 in mouse adipocytes. We therefore aimed to determine IL-6 gene expression and protein production by TNF-α/stearate treated adipocytes and investigated the mechanism involved. To test our hypothesis, 3T3-L1 mouse preadipocytes were treated with TNF-α, stearate, or TNF-α/stearate. IL-6 gene expression was assessed by quantitative real-time qPCR. IL-6 protein production secreted in the cell culture media was determined by ELISA. Acetylation of histone was analyzed by Western blotting. Il6 region-associated histone H3 lysine 9/18 acetylation (H3K9/18Ac) was determined by ChIP-qPCR. 3T3-L1 mouse preadipocytes were co-challenged with TNF-α and stearate for 24 h, which led to significantly increased IL-6 gene expression (81 ± 2.1 Fold) compared to controls stimulated with either TNF-α (38 ± 0.5 Fold; p = 0.002) or stearate (56 ± 2.0 Fold; p = 0.013). As expected, co-treatment of adipocytes with TNF-α and stearate significantly increased protein production (338 ± 11 pg/mL) compared to controls stimulated with either TNF-α (28 ± 0.60 pg/mL; p = 0.001) or stearate (53 ± 0.20 pg/mL, p = 0.0015). Inhibition of histone acetyltransferases (HATs) with anacardic acid or curcumin significantly reduced the IL-6 gene expression and protein production by adipocytes. Conversely, TSA-induced acetylation substituted the stimulatory effect of TNF-α or stearate in their synergistic interaction for driving IL-6 gene expression and protein production. Mechanistically, TNF-α/stearate co-stimulation increased the promoter-associated histone H3 lysine 9/18 acetylation (H3K9/18Ac), rendering a transcriptionally permissive state that favored IL-6 expression at the transcriptional and translational levels. Our data represent a TNF-α/stearate cooperativity model driving IL-6 expression in 3T3-L1 cells via the H3K9/18Ac-dependent mechanism, with implications for adipose IL-6 exacerbations in obesity.

Adipocyte-specific FAK deletion promotes pancreatic ß-cell apoptosis via adipose inflammatory response to exacerbate diabetes mellitus.

BACKGROUND: White adipose tissue (WAT) has a key role in maintaining energy balance throughout the body, and their dysfunction take part in the regulation of diabetes mellitus. However, the internal regulatory mechanisms underlying are still unknown. METHODS AND RESULTS: We generated adipocyte-specific FAK KO (FAK-AKO) mice and investigated their phenotype. The cascade of adipocyte, macrophage in adipocyte tissues, and pancreatic ß-cells were proposed in FAK-AKO mice and validated by cell line studies using 3T3-L1, Raw264.7 and Min6. The FAK-AKO mice exhibited glucose intolerance, reduced adipose tissue mass and increased apoptosis, lipolysis and inflammatory response in adipose tissue. We further demonstrate that adipocyte FAK deletion increases ß cell apoptosis and inflammatory infiltrates into islets, which is potentiated if mice were treated with STZ. In the STZ-induced diabetes model, FAK AKO mice exhibit less serum insulin content and pancreatic ß cell area. Moreover, serum pro-inflammatory factors increased and insulin levels decreased after glucose stimulation in FAK AKO mice. In a parallel vitro experiment, knockdown or inhibition of FAK during differentiation also increased apoptosis, lipolysis and inflammatory in 3T3-L1 adipocytes, whereas the opposite was observed upon overexpression of FAK. Moreover, coculturing LPS-treated RAW264.7 macrophages with knockdown FAK of 3T3-L1 adipocytes increased macrophage pro-inflammatory response. Furthermore, conditioned medium from above stimulated Min6 cells apoptosis (with or without STZ), whereas the opposite was observed upon overexpression of FAK. Mechanistically, FAK protein interact with TRAF6 in adipocytes and knockdown or inhibition of FAK activated TRAF6/TAK1/NF-κB signaling, which exacerbates inflammation of adipocytes themselves. CONCLUSION: Adipocyte FAK deletion promotes both adipocyte apoptosis and adipose tissue inflammation. Pro-inflammatory factors released by the FAK-null adipose tissue further trigger apoptosis in pancreatic islets induced by the administration of STZ, thereby exacerbating the diabetes mellitus. This study reveals a link between FAK-mediated adipose inflammation and diabetes mellitus, a mechanism that has not been previously recognized.

2α-Substituted Vitamin D Derivatives Effectively Enhance the Osteoblast Differentiation of Dedifferentiated Fat Cells.

The active form of vitamin D3, 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3], is a principal regulator of calcium homeostasis through activation of the vitamin D receptor (VDR). Previous studies have shown that 2α-(3-hydroxypropyl)-1,25D3 (O1C3) and 2α-(3-hydroxypropoxy)-1,25D3 (O2C3), vitamin D derivatives resistant to inactivation enzymes, can activate VDR, induce leukemic cell differentiation, and increase blood calcium levels in rats more effectively than 1,25(OH)2D3. In this study, to further investigate the usefulness of 2α-substituted vitamin D derivatives, we examined the effects of O2C3, O1C3, and their derivatives on VDR activity in cells and mouse tissues and on osteoblast differentiation of dedifferentiated fat (DFAT) cells, a cell type with potential therapeutic application in regenerative medicine. In cell culture experiments using kidney-derived HEK293 cells, intestinal mucosa-derived CaCO2 cells, and osteoblast-derived MG63 cells, and in mouse experiments, O2C2, O2C3, O1C3, and O1C4 had a weaker effect than or equivalent effect to 1,25(OH)2D3 in VDR transactivation and induction of the VDR target gene CYP24A1, but they enhanced osteoblast differentiation in DFAT cells equally to or more effectively than 1,25(OH)2D3. In long-term treatment with the compound without the medium change (7 days), the derivatives enhanced osteoblast differentiation more effectively than 1,25(OH)2D3. O2C3 and O1C3 were more stable than 1,25(OH)2D3 in DFAT cell culture. These results indicate that 2α-substituted vitamin D derivatives, such as inactivation-resistant O2C3 and O1C3, are more effective than 1,25(OH)2D3 in osteoblast differentiation of DFAT cells, suggesting potential roles in regenerative medicine with DFAT cells and other multipotent cells.

Transcriptomic Analyses Reveal the Effects of Walnut Kernel Cake on Adipose Deposition in Pigs.

With the rising cost of animal feed protein, finding affordable and effective substitutes is crucial. Walnut kernel cake, a polyphenol-, fiber-, protein- and fat-rich byproduct of walnut oil extraction, has been underexplored as a potential protein replacement in pig feed. In this study, we found that feeding large Diqing Tibetan pigs walnut kernel cake promoted adipose deposition and improved pork quality during pig growth. Transcriptome analysis revealed the upregulation of genes ANGPTL8, CCNP, ETV4, and TRIB3, associated with adipose deposition. Pathway analysis highlighted enrichment in adipose deposition-related pathways, including PPAR, insulin, PI3K-Akt, Wnt, and MAPK signaling. Further analysis identified DEGs (differentially expressed genes) positively correlated with adipose-related traits, such as PER2 and PTGES. Single-cell transcriptome data pointed to the specific expression of CD248 and PTGES in adipocyte progenitor/stem cells (APSCs), pivotal for adipocyte differentiation and adipose deposition regulation. This study demonstrates walnut kernel cake's potential to substitute soybean cake in pig feed, providing high-quality protein and promoting adipose deposition. It offers insights into feed protein replacement, human functional food, fat metabolism, and related diseases, with marker genes and pathways supporting pig breeding and pork quality improvement.

Long Noncoding RNA 6302 Regulates Chicken Preadipocyte Differentiation by Targeting SLC22A16.

The excessive deposition of abdominal adipocytes in chickens is detrimental to poultry production. However, the regulatory factors that affect abdominal adipogenesis in chickens are still poorly understood. SLC22A16 is differentially expressed in abdominal preadipocytes and 10-day differentiated adipocytes in chickens, but its role in regulating chicken adipogenesis has not been reported. In this study, the function of SLC22A16 in chicken abdominal preadipocytes was investigated. SLC22A16 is significantly upregulated during abdominal adipocyte differentiation. The overexpression of SLC2A16 upregulated the expression of adipogenic marker genes and proliferation-related genes, and promoted the proliferation of adipocytes and the accumulation of triglycerides. The knockdown of SLC22A16 downregulated the expression of adipogenic marker genes and proliferation-related genes, inhibited the proliferation of adipocytes, and impaired the accumulation of triglycerides in adipocytes. In addition, LNC6302 was differentially expressed in abdominal preadipocytes and mature adipocytes, and was significantly positively correlated with the expression of SLC22A16. Interference with LNC6302 inhibits the expression of adipogenic marker genes and proliferation-related genes. The data supported the notion that LNC6302 promotes the differentiation of chicken abdominal adipocytes by cis-regulating the expression of SLC22A16. This study identified the role of SLC22A16 in the differentiation and proliferation of chicken adipocytes, providing a potential target for improving abdominal adipogenesis in chickens.

Comparison of stromal vascular fraction cell composition between Coleman fat and extracellular matrix/stromal vascular fraction gel.

As a mechanically condensed product of Coleman fat, extracellular matrix/stromal vascular fraction gel (ECM/SVF-gel) eliminates adipocytes, concentrates SVF cells, and improves fat graft retention. This study aims to compare SVF cell composition between Coleman fat and ECM/SVF-gel. Matched Coleman fat and ECM/SVF-gel of 28 healthy women were subjected to RNA-seq, followed by functional enrichment and cell-type-specific enrichment analyses, and deconvolution of SVF cell subsets, reconstructing SVF cell composition in the transcriptome level. ECM/SVF-gels had 9 upregulated and 73 downregulated differentially expressed genes (DEGs). Downregulated DEGs were mainly associated with inflammatory and immune responses, and enriched in fat macrophages. M2 macrophages, resting CD4+ memory T cells, M1 macrophages, resting mast cells, and M0 macrophages ranked in the top five most prevalent immune cells in the two groups. The proportions of the principal non-immune cells (e.g., adipose-derived stem cells, pericytes, preadipocytes, microvascular endothelial cells) had no statistical differences between the two groups. Our findings reveal ECM/SVF-gels share the same dominant immune cells beneficial to fat graft survival with Coleman fat, but exhibiting obvious losses of immune cells (especially macrophages), while non-immune cells necessary for adipose regeneration might have no significant loss in ECM/SVF-gels and their biological effects could be markedly enhanced by the ECM/SVF-gel's condensed nature.

Effects of miR-29c on proliferation and adipogenic differentiation of porcine bone marrow mesenchymal stromal cells.

microRNAs (miRNAs), a subclass of noncoding short RNAs, direct cells fate decisions that are important for cell proliferation and cell lineage decisions. Adipogenic differentiation contributes greatly to the development of white adipose tissue, involving of highly organized regulation by miRNAs. In the present study, we screened and identified 78 differently expressed miRNAs of porcine BMSCs during adipogenic differentiation. Of which, the role of miR-29c in regulating the proliferation and adipogenic differentiation was proved and detailed. Specifically, over-expression miR-29c inhibits the proliferation and adipogenic differentiation of BMSCs, which were reversed upon miR-29c inhibitor. Interference of IGF1 inhibits the proliferation and adipogenic differentiation of BMSCs. Mechanistically, miR-29c regulates the proliferation and adipogenic differentiation of BMSCs by targeting IGF1 and further regulating the MAPK pathway and the PI3K-AKT-mTOR pathway, respectively. In conclusion, we highlight the important role of miR-29c in regulating proliferation and adipogenic differentiation of BMSCs.

Isolation and adipogenic differentiation of murine mesenchymal stem cells harvested from macrophage-depleted bone marrow and adipose tissue.

INTRODUCTION AND PURPOSE: Mouse mesenchymal stem cells (MSCs) provide a resourceful tool to study physiological and pathological aspects of adipogenesis. Bone marrow-derived MSCs (BM-MSCs) and adipose tissue-derived MSCs (ASCs) are widely used for these studies. Since there is a wide spectrum of methods available, the purpose is to provide a focused hands-on procedural guide for isolation and characterization of murine BM-MSCs and ASCs and to effectively differentiate them into adipocytes. METHODS AND RESULTS: Optimized harvesting procedures for murine BM-MSCs and ASCs are described and graphically documented. Since macrophages reside in bone-marrow and fat tissues and regulate the biological behaviour of BM-MSCs and ASCs, we included a procedure to deplete macrophages from the MSC preparations. The identity and stemness of BM-MSCs and ASCs were confirmed by flow cytometry using established markers. Since the composition and concentrations of adipogenic differentiation cocktails differ widely, we present a standardized four-component adipogenic cocktail, consisting of insulin, dexamethasone, 3-isobutyl-1-methylxanthine, and indomethacin to efficiently differentiate freshly isolated or frozen/thawed BM-MSCs and ASCs into adipocytes. We further included visualization and quantification protocols of the differentiated adipocytes. CONCLUSION: This laboratory protocol was designed as a step-by-step procedure for harvesting murine BM-MSCs and ASCs and differentiating them into adipocytes.

Development and analysis of scaffold-free adipose spheroids.

Adipose tissue plays a crucial role in metabolic syndrome, autoimmune diseases, and many cancers. Because of adipose's role in so many aspects of human health, there is a critical need for in vitro models that replicate adipose architecture and function. Traditional monolayer models, despite their convenience, are limited, showing heterogeneity and functional differences compared to 3D models. While monolayer cultures struggle with detachment and inefficient differentiation, healthy adipocytes in 3D culture accumulate large lipid droplets, secrete adiponectin, and produce low levels of inflammatory cytokines. The shift from monolayer models to more complex 3D models aims to better replicate the physiology of healthy adipose tissue in culture. This study introduces a simple and accessible protocol for generating adipose organoids using a scaffold-free spheroid model. The method, utilizing either 96-well spheroid plates or agarose micromolds, demonstrates increased throughput, uniformity, and ease of handling compared to previous techniques. This protocol allows for diverse applications, including drug testing, toxin screening, tissue engineering, and co-culturing. The choice between the two methods depends on the experimental goals, with the 96-well plate providing individualized control and the micromold offering scale advantages. The outlined protocol covers isolation, expansion, and characterization of stromal vascular fraction cells, followed by detailed steps for spheroid formation and optional downstream analyses.

Single-cell analysis reveals a subpopulation of adipose progenitor cells that impairs glucose homeostasis.

Adipose progenitor cells (APCs) are heterogeneous stromal cells and help to maintain metabolic homeostasis. However, the influence of obesity on human APC heterogeneity and the role of APC subpopulations on regulating glucose homeostasis remain unknown. Here, we find that APCs in human visceral adipose tissue contain four subsets. The composition and functionality of APCs are altered in patients with type 2 diabetes (T2D). CD9+CD55low APCs are the subset which is significantly increased in T2D patients. Transplantation of these cells from T2D patients into adipose tissue causes glycemic disturbance. Mechanistically, CD9+CD55low APCs promote T2D development through producing bioactive proteins to form a detrimental niche, leading to upregulation of adipocyte lipolysis. Depletion of pathogenic APCs by inducing intracellular diphtheria toxin A expression or using a hunter-killer peptide improves obesity-related glycemic disturbance. Collectively, our data provide deeper insights in human APC functionality and highlights APCs as a potential therapeutic target to combat T2D. All mice utilized in this study are male.

Adipocyte secreted NRG4 ameliorates age-associated metabolic dysfunction.

With the progressive aging of society, there is an increasing prevalence of age-related diseases that pose a threat to the elderly's quality of life. Adipose tissue, a vital energy reservoir with endocrine functions, is one of the most vulnerable tissues in aging, which in turn influences systematic aging process, including metabolic dysfunction. However, the underlying mechanism is still poorly understood. In this study, we found that NRG4, a novel adipokine, is obviously decreased in adipocyte tissues and serums during aging. Moreover, delivered recombinant NRG4 protein (rNRG4) into aged mice can ameliorate age-associated insulin resistance, glucose disorders and other metabolic disfunction. In addition, rNRG4 treatment alleviates age-associated hepatic steatosis and sarcopenia, accompanied with altered gene signatures. Together, these results indicate that NRG4 plays a key role in the aging process and is a therapeutic target for the treatment of age-associated metabolic dysfunction.

Anti-Obesity Activities of the Compounds from Perilla frutescens var. acuta and Chemical Profiling of the Extract.

Perilla frutescens var. acuta (Lamiaceae) is widely used not only as an oil or a spice, but also as a traditional medicine to treat colds, coughs, fever, and indigestion. As an ongoing effort, luteolin-7-O-diglucuronide (1), apigenin-7-O-diglucuronide (2), and rosmarinic acid (3) isolated from P. frutescens var. acuta were investigated for their anti-adipogenic and thermogenic activities in 3T3-L1 cells. Compound 1 exhibited a strong inhibition against adipocyte differentiation by suppressing the expression of Pparg and Cebpa over 52.0% and 45.0%, respectively. Moreover, 2 inhibited the expression of those genes in a dose-dependent manner [Pparg: 41.7% (5 µM), 62.0% (10 µM), and 81.6% (50 µM); Cebpa: 13.8% (5 µM), 18.4% (10 µM), and 37.2% (50 µM)]. On the other hand, the P. frutescens var. acuta water extract showed moderate thermogenic activities. Compounds 1 and 3 also induced thermogenesis in a dose-dependent manner by stimulating the mRNA expressions of Ucp1, Pgc1a, and Prdm16. Moreover, an LC-MS/MS chromatogram of the extract was acquired using UHPLC-MS2 and it was analyzed by feature-based molecular networking (FBMN) and the Progenesis QI software (version 3.0). The chemical profiling of the extract demonstrated that flavonoids and their glycoside derivatives, including those isolated earlier as well as rosmarinic acid, are present in P. frutescens var. acuta.

ADH1B, the adipocyte-enriched alcohol dehydrogenase, plays an essential, cell-autonomous role in human adipogenesis.

Alcohol dehydrogenase 1B (ADH1B) is a primate-specific enzyme which, uniquely among the ADH class 1 family, is highly expressed both in adipose tissue and liver. Its expression in adipose tissue is reduced in obesity and increased by insulin stimulation. Interference with ADH1B expression has also been reported to impair adipocyte function. To better understand the role of ADH1B in adipocytes, we used CRISPR/Cas9 to delete ADH1B in human adipose stem cells (ASC). Cells lacking ADH1B failed to differentiate into mature adipocytes manifested by minimal triglyceride accumulation and a marked reduction in expression of established adipocyte markers. As ADH1B is capable of converting retinol to retinoic acid (RA), we conducted rescue experiments. Incubation of ADH1B-deficient preadipocytes with 9-cis-RA, but not with all-transretinol, significantly rescued their ability to accumulate lipids and express markers of adipocyte differentiation. A homozygous missense variant in ADH1B (p.Arg313Cys) was found in a patient with congenital lipodystrophy of unknown cause. This variant significantly impaired the protein's dimerization, enzymatic activity, and its ability to rescue differentiation in ADH1B-deficient ASC. The allele frequency of this variant in the Middle Eastern population suggests that it is unlikely to be a fully penetrant cause of severe lipodystrophy. In conclusion, ADH1B appears to play an unexpected, crucial and cell-autonomous role in human adipocyte differentiation by serving as a necessary source of endogenous retinoic acid.

Effects of glucocorticoids on adipose tissue plasticity.

Glucocorticoids (GCs) play an important role in metabolic adaptation, regulating carbohydrate-lipid homeostasis and the immune system. Because they also have anti-inflammatory and immunosuppressive properties, synthetic analogues of GCs have been developed and are widely used in the treatment of chronic inflammatory conditions and in organ transplantation. GCs are among the most commonly prescribed drugs in the world. However, long term and high GC doses can cause side effects such as GC-induced diabetes and lipodystrophy. In recent years, a large number of independent studies have reported the effects of constitutive and adipocyte-specific deletion of the GC receptor (GR) in mice under different diets and treatments, resulting in contrasting phenotypes. To avoid potential compensatory mechanisms associated with the constitutive adipocyte GR silencing during adipose tissue development, our team has generated an inducible mouse model of GR deletion specifically in the adipocyte (AdipoGR-KO). Using this mouse model, we were able to demonstrate the critical role of the adipocyte GR in GC-induced metabolic changes. Indeed, under conditions of hypercorticism, AdipoGR-KO mice showed an improvement in glucose tolerance and insulin sensitivity, as well as in lipid profile, despite a massive increase in adiposity. This result is explained by a densification of adipose tissue vascularization, highlighting the repressive role of adipocyte GR in the healthy expansion of this tissue. Our work has largely contributed to the demonstration of the important role of the adipocyte GR in the physiology and pathophysiology of the adipose tissue and its impact on energy homeostasis.