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Frontiers in Endocrinology 2024The beneficial effect of thermogenic adipocytes in maintaining body weight and protecting against metabolic disorders has raised interest in understanding the regulatory...
BACKGROUND
The beneficial effect of thermogenic adipocytes in maintaining body weight and protecting against metabolic disorders has raised interest in understanding the regulatory mechanisms defining white and beige adipocyte identity. Although alternative splicing has been shown to propagate adipose browning signals in mice, this has yet to be thoroughly investigated in human adipocytes.
METHODS
We performed parallel white and beige adipogenic differentiation using primary adipose stem cells from 6 unrelated healthy subjects and assessed differential gene and isoform expression in mature adipocytes by RNA sequencing.
RESULTS
We find 777 exon junctions with robust differential usage between white and beige adipocytes in all 6 subjects, mapping to 562 genes. Importantly, only 10% of these differentially spliced genes are also differentially expressed, indicating that alternative splicing constitutes an additional layer of gene expression regulation during beige adipocyte differentiation. Functional classification of alternative isoforms points to a gain of function for key thermogenic transcription factors such as and , and enzymes such as , or . We find that a large majority of the splice variants arise from differential TSS usage, with beige-specific TSSs being enriched for PPARγ and MED1 binding compared to white-specific TSSs. Finally, we validate beige specific isoform expression at the protein level for two thermogenic regulators, PPARγ and PEMT.
DISCUSSION
These results suggest that differential isoform expression through alternative TSS usage is an important regulatory mechanism for human adipocyte thermogenic specification.
Topics: Humans; Adipocytes, Beige; Thermogenesis; Alternative Splicing; Protein Isoforms; Cell Differentiation; Adipogenesis; Male; Female; Adult; Cells, Cultured; Gene Expression Regulation; PPAR gamma
PubMed: 38859907
DOI: 10.3389/fendo.2024.1395750 -
Adipocyte Dec 2024microRNAs (miRNAs), a subclass of noncoding short RNAs, direct cells fate decisions that are important for cell proliferation and cell lineage decisions. Adipogenic...
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 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.
Topics: Animals; Mesenchymal Stem Cells; MicroRNAs; Swine; Adipogenesis; Cell Proliferation; Cell Differentiation; Cells, Cultured; Signal Transduction; Adipocytes; Bone Marrow Cells
PubMed: 38858810
DOI: 10.1080/21623945.2024.2365211 -
Nature Aging Jun 2024Thermogenic beige adipocytes are recognized as potential therapeutic targets for combating metabolic diseases. However, the metabolic advantages that they offer are...
Thermogenic beige adipocytes are recognized as potential therapeutic targets for combating metabolic diseases. However, the metabolic advantages that they offer are compromised with aging. Here we show that treating mice with estrogen (E2), a hormone that decreases with age, can counteract the age-related decline in beige adipogenesis when exposed to cold temperature while concurrently enhancing energy expenditure and improving glucose tolerance in mice. Mechanistically, we found that nicotinamide phosphoribosyl transferase (NAMPT) plays a pivotal role in facilitating the formation of E2-induced beige adipocytes, which subsequently suppresses the onset of age-related endoplasmic reticulum (ER) stress. Furthermore, we found that targeting NAMPT signaling, either genetically or pharmacologically, can restore the formation of beige adipocytes by increasing the number of perivascular adipocyte progenitor cells. Conversely, the absence of NAMPT signaling prevents this process. Together, our findings shed light on the mechanisms regulating the age-dependent impairment of beige adipocyte formation and underscore the E2-NAMPT-controlled ER stress pathway as a key regulator of this process.
Topics: Nicotinamide Phosphoribosyltransferase; Animals; Adipogenesis; Endoplasmic Reticulum Stress; Mice; Aging; Estrogens; Adipocytes, Beige; Cytokines; Signal Transduction; Female; Mice, Inbred C57BL; Energy Metabolism
PubMed: 38858606
DOI: 10.1038/s43587-024-00633-z -
Archives of Gerontology and Geriatrics May 2024Total saponins from Panax japonicus (TSPJ) have many beneficial physiological activities, particularly in alleviating the damages of aging and abnormal lipid metabolism....
Total saponins from Panax japonicus (TSPJ) have many beneficial physiological activities, particularly in alleviating the damages of aging and abnormal lipid metabolism. This work used mice models to investigate if TSPJ reduced obesity and regulated metabolic functions via the intestinal microbiota, the disturbance of which has been shown to cause aging-related diseases. The results showed that TSPJ significantly reduced the weight and blood lipid level of aging mice. Further analyses showed that TSPJ significantly inhibited adipogenesis, changed the composition of the intestinal flora, and protected the integrity of the intestinal barrier. It was inferred from the accumulated experimental data that TSPJ helped to combat obesity in aging mice by regulating the intestinal microbiota and promoting microbial metabolism.
PubMed: 38851092
DOI: 10.1016/j.archger.2024.105500 -
Journal of Agricultural and Food... Jun 2024Intramuscular fat (IMF) contributed positively to pork quality, whereas subcutaneous fat (SCF) was often considered to be a detrimental factor impacting growth and...
Intramuscular fat (IMF) contributed positively to pork quality, whereas subcutaneous fat (SCF) was often considered to be a detrimental factor impacting growth and carcass traits. Reducing SCF while maintaining optimal IMF levels requires a thorough understanding of the adipogenic differences between these two adipose depots. Our study explored the differences in adipogenesis between porcine IMF and SCF, and the results showed that subcutaneous adipocytes (SCAs) demonstrate a greater potential for adipogenic differentiation, both in vivo and in vitro. Lipidomic and transcriptomic analyses suggested that intramuscular adipocytes (IMAs) are more inclined to biosynthesize unsaturated fatty acids. Furthermore, single-cell RNA sequencing (scRNA-seq) was employed to dissect the intrinsic and microenvironmental discrepancies in adipogenesis between porcine IMF and SCF. Comparative analysis indicated that SCF was enriched with preadipocytes, exhibiting an enhanced adipogenic potential, while IMF was characterized by a higher abundance of stem cells. Furthermore, coculture analyses of porcine intramuscular adipogenic cells and myogenetic cells indicated that the niche of IMAs inhibited its adipogenic differentiation. Cell communication analysis identified 160 ligand-receptor pairs and channels between adipogenic and myogenetic cells in IMF. Collectively, our study elucidated two intrinsic and microenvironmental novel mechanisms underpinning the divergence in adipogenesis between porcine SCF and IMF.
PubMed: 38848240
DOI: 10.1021/acs.jafc.4c01044 -
Journal of Lipid Research Jun 2024The full understanding of molecular mechanisms of cell differentiation requires a holistic view. Here we combine label-free FTIR and Raman hyperspectral imaging with...
The full understanding of molecular mechanisms of cell differentiation requires a holistic view. Here we combine label-free FTIR and Raman hyperspectral imaging with data mining to detect the molecular cell composition enabling noninvasive monitoring of cell differentiation and identifying biochemical heterogeneity. Mouse adipose-derived mesenchymal stem cells (AD-MSCs) undergoing adipogenesis were followed by Raman and FT-IR imaging, Oil Red, and immunofluorescence. A workflow of the data analysis (IRRSmetrics4stem) was designed to identify spectral predictors of adipogenesis and test machine-learning (ML) methods (hierarchical clustering, PCA, PLSR) for the control of the AD-MSCs differentiation degree. IRRSmetrics4stem provided insights into the chemism of adipogenesis. With single-cell tracking, we established IRRS metrics for lipids, proteins, and DNA variations during AD-MSCs differentiation. The over 90% predictive efficiency of the selected ML methods proved the high sensitivity of the IRRS metrics. Importantly, the IRRS metrics unequivocally recognize a switch from proliferation to differentiation. This study introduced a new bioassay identifying molecular markers indicating molecular transformations and delivering rapid and machine learning-based monitoring of adipogenesis that can be relevant to other differentiation processes. Thus, we introduce a novel, rapid, machine learning-based bioassay to identify molecular markers of adipogenesis. It can be relevant to identification of differentiation-related molecular processes in other cell types, and beyond the cell differentiation including progression of different cellular pathophysiologies reconstituted in vitro.
PubMed: 38844049
DOI: 10.1016/j.jlr.2024.100573 -
IScience Jun 2024Obesity, characterized by enlarged and dysfunctional adipose tissue, is among today's most pressing global public health challenges with continuously increasing...
Obesity, characterized by enlarged and dysfunctional adipose tissue, is among today's most pressing global public health challenges with continuously increasing prevalence. Despite the importance of post-translational protein modifications (PTMs) in cellular signaling, knowledge of their impact on adipogenesis remains limited. Here, we studied the temporal dynamics of transcriptome, proteome, central carbon metabolites, and the acetyl- and phosphoproteome during adipogenesis using LC-MS/MS combined with PTM enrichment strategies on human (SGBS) and mouse (3T3-L1) adipocyte models. Both cell lines exhibited unique PTM profiles during adipogenesis, with acetylated proteins being enriched for central energy metabolism, while phosphorylated proteins related to insulin signaling and organization of cellular structures. As candidates with strong correlation to the adipogenesis timeline we identified CD44 and the acetylation sites FASN_K673 and IDH_K272. While results generally aligned between SGBS and 3T3-L1 cells, details appeared cell line specific. Our datasets on SGBS and 3T3-L1 adipogenesis dynamics are accessible for further mining.
PubMed: 38840842
DOI: 10.1016/j.isci.2024.109711 -
Orthopaedic Journal of Sports Medicine Jun 2024The effect of local corticosteroid (CS) injections on rotator cuff muscles remains poorly defined, despite the significance of muscle quality as a crucial prognostic...
Influence of Frequent Corticosteroid Local Injections on the Expression of Genes and Proteins Related to Fatty Infiltration, Muscle Atrophy, Inflammation, and Fibrosis in Patients With Chronic Rotator Cuff Tears: A Pilot Study.
BACKGROUND
The effect of local corticosteroid (CS) injections on rotator cuff muscles remains poorly defined, despite the significance of muscle quality as a crucial prognostic factor for patients with rotator cuff tears (RCTs).
PURPOSE
To compare alterations in gene and protein expression patterns in the rotator cuff muscles of patients with RCTs who received frequent joint CS injections with alterations in those without a history of CS injections.
STUDY DESIGN
Controlled laboratory study.
METHODS
A total of 24 rotator cuff muscle samples with medium-sized tears from 12 patients with a frequent joint CS injection history (steroid group; 7 men and 5 women who had received ≥5 injections with at least 1 within the previous 3 months; mean age, 63.0 ± 7.2 years) and 12 age- and sex-matched control patients without a history of CS injections (no-steroid group) were acquired. Alterations in the expression of genes and proteins associated with adipogenesis, myogenesis, inflammation, and muscle fibrosis were compared between the groups using quantitative reverse transcription-polymerase chain reaction, Western blotting, and immunohistochemistry. Statistical analysis included comparison of group means using the Mann-Whitney test, chi-square test, or Fisher exact test and logistic regression for multivariate analysis.
RESULTS
In the steroid group, the mRNA expression levels of adipogenic CCAAT/enhancer-binding protein alpha (C/EBPα; = .008) and muscle atrophy-related genes (atrogin; = .019) were significantly higher, and those of myogenic differentiation 1 (MyoD; = .035), inflammatory interleukin 6 (IL-6; = .035), and high mobility group box 1 ( = .003) were significantly lower compared with the no-steroid group. In addition, MyoD ( = .041) and IL-6 ( = .026) expression were decreased in the steroid versus no-steroid group. Immunohistochemistry revealed increased expression of C/EBPα and atrogin and decreased expression of MyoD and IL-6 in the steroid versus no-steroid group.
CONCLUSION
Patients with RCTs and a history of frequent CS injections exhibited an upregulation of adipogenic and muscle atrophy-related genes and proteins within the rotator cuff muscles and a downregulation in the expression of myogenic and inflammatory genes and proteins in the same muscles.
CLINICAL RELEVANCE
These altered gene and protein expressions by frequent local CS injections may cause poor outcomes in patients with RCTs.
PubMed: 38840789
DOI: 10.1177/23259671241252421 -
Biomedicine & Pharmacotherapy =... Jul 2024Glinus oppositifolius L., a member of the Molluginaceae family, has a long-standing history of utilization as both a vegetable and a medicinal agent across numerous...
Glinus oppositifolius L., a member of the Molluginaceae family, has a long-standing history of utilization as both a vegetable and a medicinal agent across numerous countries. This plant possesses a diverse range of pharmacological activities and attracts scientific interest in studying its chemical profile. The present phytochemical investigation of the plant resulted in the isolation of eleven new triterpenoid saponins, accompanied by three known compounds. Their structures were elucidated by intensive spectroscopic analysis, DFT calculations, and comparison with previously reported data. The isolates were evaluated for their anti-adipogenic effect and cytotoxicity against human cancer cell lines, namely, colorectal carcinoma HCT116, hepatoblastoma cell HepG2, breast cancer cell MDA-MB-231, and human lung adenocarcinoma cell A549. Compounds 5, 7, and 13 exhibited a potent inhibitory effect against the differentiation of preadipocyte 3T3-L1. In addition, compound 13 displayed inhibitory effects against the growth of A549 cancer cells.
Topics: Saponins; Humans; Triterpenes; Animals; Mice; Plant Components, Aerial; 3T3-L1 Cells; Adipogenesis; A549 Cells; Antineoplastic Agents, Phytogenic; Hep G2 Cells; Cell Line, Tumor; Plant Extracts; Cell Differentiation; HCT116 Cells
PubMed: 38838506
DOI: 10.1016/j.biopha.2024.116851 -
Proceedings of the National Academy of... Jun 2024Alcohol 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...
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 expression has also been reported to impair adipocyte function. To better understand the role of ADH1B in adipocytes, we used CRISPR/Cas9 to delete 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 (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.
Topics: Humans; Alcohol Dehydrogenase; Adipogenesis; Adipocytes; Tretinoin; Cell Differentiation; CRISPR-Cas Systems; Mutation, Missense; Adipose Tissue
PubMed: 38838011
DOI: 10.1073/pnas.2319301121