Adipocyte最新文献

Mitochondria are essential for generating cellular energy and are significant in the pathogenesis of obesity. Human visceral and subcutaneous preadipocytes (HPA-v and HPA-s) were cultured into mature adipocytes. Intracellular triglyceride (TG) content was assessed using oil-red O staining and tissue triglyceride determination. Mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) levels were measured with fluorescent indicators. Gene and protein expression related to mitochondrial biogenesis were analyzed by real-time quantitative PCR and Western blotting. Morphological changes were observed via electron microscopy. Results show that PDBSN significantly increased MMP while decreasing TG and ROS levels. The transcription and protein levels of PGC1-α and MTFA were upregulated, and mitochondrial fusion and fission markers (MFN1, MFN2, NRF1, DRP1) were elevated. Additionally, PDBSN enhanced maximum respiratory capacity and reduced ROS. These findings suggest that PDBSN improves mitochondrial function, providing insights for obesity treatment and metabolic disease management.

Obesity is a major global health issue. This study aimed to elucidate its molecular mechanisms by analysing the expression of lncRNAs, miRNAs, and mRNAs in visceral adipose tissue. Through integrated transcriptome sequencing and bioinformatics analysis of obese and normal groups, we observed 118, 92 and 227 differentially expressed lncRNAs, miRNAs and mRNAs, respectively. Functional enrichment analysis revealed these genes were primarily involved in immune response and inflammation-related pathways. A competing endogenous RNA (ceRNA) network was constructed, identifying key interactions among five target genes, including SDC4. Validation confirmed SDC4 was significantly upregulated in obese subjects, and this expression level positively correlated with body mass index and triglyceride. These findings suggest that SDC4 offers the possibility of being a therapeutic target for obesity.

We discovered two adult sisters in Colombia, lineally consanguineous, with severe obesity and undetectable serum leptin levels despite markedly elevated body fat. Their clinical profile included childhood-onset extreme weight gain, intense hunger, hyperphagia, hypogonadotropic hypogonadism, and family history of obesity. Direct sequencing of the LEP gene revealed a novel homozygous missense mutation in exon 3 (c.350G>T [p.C117F]). The presence of this mutation, undetectable leptin, and severe obesity confirmed a diagnosis of monogenic leptin deficiency. Here we describe the clinical outcomes of a 12-month treatment with recombinant human leptin (metreleptin). Metabolic and endocrine assessments were conducted before and after therapy. Metreleptin therapy significantly reduced BMI: from 59 to 38 kg/m² (OBX1, age 27) and 60 to 48 kg/m² (OBX2, age 24). Total body fat mass decreased, serum lipids normalized, and insulin sensitivity improved. Hypogonadotropic hypogonadism reversed, and menstruation resumed. Thus, metreleptin reversed the major metabolic and endocrine abnormalities associated with leptin deficiency in these sisters. Limitations include the small sample size, absence of a control group, and lack of anti-metreleptin antibody measurements. Nevertheless, our findings support that leptin replacement with metreleptin is currently the only effective hormonal treatment for this monogenic form of human obesity.

The expression of CAPG (capping actin protein, gelsolin-like) is upregulated in visceral white adipose tissue of high-fat diet -fed mice; however, its impact on adipocyte functionality remains unclear. We observed upregulated CAPG expression in the epididymal adipose tissue of high-fat diet-fed mice. To investigate the impact of CAPG on adipocyte differentiation and function, we generated a Capg knockdown 3T3-L1 cell line and induced adipogenic differentiation to mature adipocytes. Adipogenesis was assessed via Oil Red O and BODIPY staining, revealing that Capg knockdown markedly suppressed adipogenesis. Western blot analysis demonstrated that CAPG depletion reduced PPARγ expression. Additionally, Western blot analysis revealed that Capg knockdown significantly enhanced lipid utilization in adipocytes. ELISA and qPCR results further demonstrated that Capg knockdown effectively attenuated inflammatory responses in adipocytes. In conclusion, CAPG promotes adipogenesis and inflammatory responses, suggesting that targeted inhibition of CAPG may represent a potential therapeutic strategy for obesity-associated adipose tissue dysfunction.

Background: Mature adipocytes are difficult to study ex vivo, prompting the use of human adipose progenitor cells (hAPCs). However, hAPCs undergo replicative senescence, limiting their utility in long-term studies.

Methods: We inserted human telomerase reverse transcriptase (TERT) into the AAVS1 locus of CD55+ hAPCs derived from abdominal subcutaneous adipose tissue, and characterized the cells before and after adipogenic differentiation.

Results: TERT-hAPCs retained proliferative and adipogenic capacities for over 80 passages, comparable to early-passage wild type hAPCs. Transcriptomic and proteomic analyses confirmed strong adipocyte gene expression. Functionally, TERT-hAPCs responded to insulin and lipolytic stimuli (isoprenaline, dibutyryl cAMP, TNF-α). They adapted well to both 2D and 3D cultures, with improved adipogenesis under spheroid conditions.

Conclusion: Immortalization of CD55+ hAPCs yields cells with stable proliferative and adipogenic capacity across passages. Being cryopreservable and suitable for both 2D and 3D cultures, TERT-hAPCs offer a reliable, reusable model system for adipocyte studies using cells with a consistent genetic background.

Chronic inflammation in obesity can induce complications such as diabetes and cardiovascular disease. Visceral adipose tissue is the main source of inflammation, but it is difficult to regulate effectively. Here, we investigated whether ES suppressed inflammation in eWAT and reduced chronic inflammation in obese individuals. We established a high-fat diet (HFD) model with C57BL/6J mice to measure chronic inflammation in obesity. In addition, the sympathetic nerve activity (SNA) was measured with the electrophysiological technique, the immunostaining and flow cytometry were used to detect the Y1 receptors in macrophage. Finally, the key role of the M1/M2 polarization in white adipose tissues by activating the Y1 receptor was verified by Y1 receptor antagonist BIBP3226. ES reduced the contents of IL-1β, TNF-α, IL-6 and TGF-β in the plasma and the mRNA expression of il-1 and tnfα in eWAT. Also, ES suppressed SNA in eWAT which regulated NPY1R receptor. In addition, ES induced M1/M2 polarization in eWAT via the Y1 receptor. The injection of a Y1 receptor (NPY1R) antagonist BIBP3226 restrained M1/M2 polarization. Further studies revealed that ES regulated sympathetic axons in eWAT to activate the Y1 receptor. This research demonstrates ES reduce chronic inflammation e mechanism is associated with the sympathetic Y1 receptor pathway, which promotes M1/M2 polarization.

Different adipose tissues (AT) have been described, including subcutaneous and visceral tissues (SCAT and VAT). They display different morphological structures, physiological and metabolic functions. Imaging adipocytes in the whole AT was not feasible because of the large adipocyte sizes and the lipid-full content of the droplets that increased the refractive index. Tissue clearing is then required mainly through a delipidation step, which induces also a tissue shrinkage. Our aim was to image in 3D freshly extracted adipocytes and compare them to those within their tissues. Trout ATs were stained with 5DTAF (extracellular matrix) and Nile Red (lipids). After clearing with Histodenz, 3D images were obtained using a confocal microscope, and adipocytes were segmented and measured. In situ, major differences in adipocyte size and shape were observed between the VAT and SCAT. Ex situ, only the size mattered because all cells were round outside their tissues. This method can be applied to other species, such as mice. In situ, adipocyte sphericity was even higher in the SCAT from a Swiss and a C57Bl6. This approach demonstrates that 3D adipocyte imaging with lipid labeling enables accurate morphological characterization, provides insights into depot-specific structural features, and supports optimization of cell isolation protocols.

Obesity is a global health concern that promotes chronic low-grade inflammation, leading to insulin resistance, a key factor in many metabolic diseases. Angiotensin 1-7 (Ang 1-7), a component of the renin-angiotensin system (RAS), exhibits anti-inflammatory effects in obesity and related disorders, though its mechanisms remain unclear. In this study, we examined the effect of Ang 1-7 on inflammation of white adipose tissue (WAT) in dietary-induced obese mice. Monocyte chemoattractant protein-1 (MCP-1) produced by white adipocytes and tumour necrosis factor-α (TNF-α) produced by macrophages are pro-inflammatory cytokines and interact to form a pathogenic loop to exacerbate obesity-induced inflammation. We found that Ang 1-7 reduced MCP-1 and TNF-α gene expressions and the number of crown-like structures, which are histological hallmarks of the pro-inflammatory process, in visceral epididymal WAT (eWAT) and reduced circulating MCP-1 and TNF-α levels, accompanied by improvement in insulin resistance, in dietary-induced obese mice. Furthermore, Ang 1-7 reduced MCP-1 and TNF-α secretions in 3T3-L1 white adipocytes and RAW 264.7 macrophages, respectively, which are in vitro experimental models mimicking obesity condition. Our results suggest that Ang 1-7 directly acts on WAT to mitigate obesity-induced inflammation. Thus, this study provides novel insights into the underlying mechanism of anti-obesity effects of Ang 1-7.

Melanin-concentrating hormone signalling pathways in the central nervous system are of significant clinical interest in treating appetite, sleep, and mood disorders. However, with the additional discovery of active MCH signalling pathways in peripheral tissues, knowing the degree to which cellular context influence MCH receptor function is increasingly important. In this study, we discovered MCH-mediated signalling responses that demonstrated bell-shaped dose response curves in multiple assays using both pre- and post-adipocyte 3T3-L1 models. MCH facilitated cell adhesion in pre-adipocytes, increased both the number and size of lipid droplets and inhibited lipolysis in adipocytes, with a maximum effective dose at 1 nM MCH. We hypothesize that the concentration of MCH cells are exposed to influences G protein bias at MCHR1 and/or signal switching to an unidentified pathway. Furthermore, this study elucidates the importance of hormone concentration when measuring GPCR signalling pathways in cell culture and tissue models.

Sequestration of free fatty acids (FFA) inside white adipose tissue (WAT) may reduce plasma FFA levels and prevent lipotoxicity in other organs. However, it is poorly understood how WAT responds to this metabolic stress. As albumin promotes FFA release from WAT, and thus albumin deficiency should promote FFA sequestration, we studied albumin knockout (Alb^-/-) mice and their wildtype (WT) littermates (eight-week-old males). Transmission electron microscopy and molecular analyses were used for characterization. There was no significant difference between genotypes for WAT mass, adipocyte size or triacylglycerol (TAG) content. No signs of cell death were observed in Alb^-/- adipocytes, suggesting a tolerance to the metabolic challenge. Alb^-/- adipocytes exhibited a lower density of caveolae with smaller invagination depths, indicating a potential adaptation to reduce FFA transport. A significantly higher abundance of micro-lipid droplets was observed in Alb^-/- mice, which may result from a rapid substrate cycle with high lipolysis and re-esterification. In support of the ultrastructural phenotype, lipidomic analysis also demonstrated a significant difference between Alb^-/- and WT for TAG composition. Our results showed that when no albumin is present to facilitate FFA mobilization, WAT can chronically adapt to protect the adipocytes in both morphological and molecular manners.