Aspirin-induced inhibition of adipogenesis was p53-dependent and associated with inactivation of pentose phosphate pathway

The transmembrane protein TMEM182 promotes fat deposition and alters metabolomics and lipidomics

TMEM182, a transmembrane protein highly expressed in muscle and adipose tissues, plays a crucial role in muscle cell differentiation, metabolism, and signaling. However, its role in fat deposition and metabolism is still unknown. In this study, we used overexpression and knockout models to examine the impact of TMEM182 on fat synthesis and metabolism. Our results showed that TMEM182 overexpression increased the expression of fat synthesis-related genes and promoted the differentiation of preadipocytes into fat cells. In TMEM182 knockout mice, there was a significant decrease in abdominal fat deposition. RNA sequencing results showed that TMEM182 overexpression in preadipocytes enhanced the activity of pathways related to fat formation, ECM-receptor interaction, and cell adhesion. Furthermore, our analysis using UPLC-MS/MS showed that TMEM182 significantly altered the metabolite and lipid content and composition in chicken breast muscle. Specifically, TMEM182 increased the content of amino acids and their derivatives in chicken breast muscle, promoting amino acid metabolic pathways. Lipidomics also revealed a significant increase in the content of glycerophospholipids, sphingolipids, and phospholipids in the breast muscle after TMEM182 overexpression. These findings suggest that TMEM182 plays a crucial role in regulating fat deposition and metabolism, making it a potential target for treating obesity-related diseases and animal breeding.

Challenges in Pharmacological Intervention in Perilipins (PLINs) to Modulate Lipid Droplet Dynamics in Obesity and Cancer

Perilipins (PLINs) are the most abundant proteins in lipid droplets (LD). These LD-associated proteins are responsible for upgrading LD from inert lipid storage structures to fully functional organelles, fundamentally integrated in the lipid metabolism. There are five distinct perilipins (PLIN1-5), each with specific expression patterns and metabolic activation, but all capable of regulating the activity of lipases on LD. This plurality creates a complex orchestrated mechanism that is directly related to the healthy balance between lipogenesis and lipolysis. Given the essential role of PLINs in the modulation of the lipid metabolism, these proteins can become interesting targets for the treatment of lipid-associated diseases. Since reprogrammed lipid metabolism is a recognized cancer hallmark, and obesity is a known risk factor for cancer and other comorbidities, the modulation of PLINs could either improve existing treatments or create new opportunities for the treatment of these diseases. Even though PLINs have not been, so far, directly considered for pharmacological interventions, there are many established drugs that can modulate PLINs activity. Therefore, the aim of this study is to assess the involvement of PLINs in diseases related to lipid metabolism dysregulation and whether PLINs can be viewed as potential therapeutic targets for cancer and obesity.

Expression Profile and Regulatory Properties of m6A-Modified circRNAs in the Longissimus Dorsi of Queshan Black and Large White Pigs

It is well known that N6-methyladenosine (m6A) is the most abundant modification in linear RNA molecules, but many circRNA molecules have now been found to have a wide range of m6A modification sites as well. However, there are few relevant studies and information on the expression profile and functional regulatory properties of m6A-modified circRNAs (m6A-circRNAs) in longissimus dorsi. In this study, a total of 12 putative m6A-circRNAs were identified and characterized in the longissimus dorsi of Queshan Black and Large White pigs-8 of them were significantly more expressed in the longissimus dorsi of Queshan Black than in Large White pigs, while the other 4 were the opposite. These 12 putative m6A-circRNAs were also found to act as miRNA sponge molecules to regulate fat deposition by constructing the ceRNA regulatory network. Enrichment analysis also revealed that the 12 m6A-circRNAs parent genes and their adsorbed miRNA target genes were widely involved in fat deposition and cell proliferation and differentiation-related pathways, such as the HIF-1 signaling pathway, the pentose phosphate pathway, the MAPK signaling pathway, the glycosphingolipid biosynthesis-lacto and neolacto series, and the TNF signaling pathway, suggesting that the analyzed m6A-circRNAs may be largely involved in the formation of pork quality. These results provide new information to study the regulatory properties of m6A-circRNAs in the formation of pork quality.

The preventive effects of aspirin on preeclampsia based on network pharmacology and bioinformatics

This study aimed to reveal the key targets and molecular mechanisms of aspirin in preventing preeclampsia. We used bioinformatics databases to collect the candidate targets for aspirin and preeclampsia. The biological functions and signaling pathways of the intersecting targets were analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Then, the hub targets were identified by cytoscape plugin cytoHubba from the protein-protein interaction network. We collected 90 targets for aspirin in preventing preeclampsia. The biological processes of the intersecting targets are mainly involved in xenobiotic metabolic process, inflammatory response, negative regulation of apoptotic process, and protein phosphorylation. The highly enriched pathways were FoxO signaling pathway, circadian rhythm, insulin resistance, arachidonic acid metabolism, and drug metabolism-cytochrome P450. The hub targets for aspirin in preventing preeclampsia were tumor protein p53 (TP53), C-X-C motif chemokine ligand 8 (CXCL8), mitogen-activated protein kinase 3 (MAPK3), mitogen-activated protein kinase 1 (MAPK1), mitogen-activated protein kinase 14 (MAPK14), epidermal growth factor receptor (EGFR), estrogen receptor (ESR1), and prostaglandin-endoperoxide synthase 2 (PTGS2). Molecular docking results showed good bindings between the proteins and aspirin. In conclusion, these findings highlight the key targets and molecular mechanisms of aspirin in preventing preeclampsia.

Characterization of transcriptional landscape in bone marrow-derived mesenchymal stromal cells treated with aspirin by RNA-seq

INTRODUCTION

Aspirin is a common antipyretic, analgesic, and anti-inflammatory drug, which has been reported to extend life in animal models and application in the treatment of aging-related diseases. However, it remains unclear about the effects of aspirin on bone marrow-derived mesenchymal stromal cells (BM-MSCs). Here, we aimed to analyze the influence of aspirin on senescence and young BM-MSCs.

METHODS

BM-MSCs were serially passaged to construct a replicative senescence model. SA-β-gal staining, PCR, western blot, and RNA-sequencing were performed on BM-MSCs with or without aspirin treatment, to examine aspirin's impact on bone marrow-derived mesenchymal stem cells.

RESULTS

SA-β-gal staining, PCR, and western blot revealed that aspirin could alleviate the cellular expression of senescence-related indicators of BM-MSCs, including a decrease of SA-β-gal-positive cells and staining intensity, and downregulation of p16, p21, and p53 expression after aspirin treatment. RNA-sequencing results shown in the biological processes related to aging, aspirin could influence cellular immune response and lipid metabolism.

CONCLUSION

The efficacy of aspirin for retarding senescence of BM-MSCs was demonstrated. Our study indicated that the mechanisms of this delay might involve influencing immune response and lipid metabolism.

Effect of acetylsalicylic acid on inflamed adipose tissue. Insulin resistance and hepatic steatosis in a mouse model of diet-induced obesity

AIMS

Obesity represents a global health problem. Excessive caloric intake promotes the release of inflammatory mediators by hypertrophic adipocytes and obesity-induced inflammation is now recognized as a risk factor for the development of several diseases, such as cardiovascular diseases, insulin resistance, type-II diabetes, liver steatosis and cancer. Since obesity causes inflammation, we tested the ability of acetylsalicylic acid (ASA), a potent anti-inflammatory drug, in counteracting this inflammatory process and in mitigating obesity-associated health complications.

MAIN METHODS

Mice were fed with standard (SD) or high fat diet (HFD) for 3 months and then treated with acetylsalicylic acid for the subsequent two months. We then analyzed the metabolic and inflammatory status of their adipose and liver tissue by histological, molecular and biochemical analysis.

KEY FINDINGS

Although ASA did not exert any effect on body weight, quantification of adipocyte size revealed that the drug slightly reduced adipocyte hypertrophy, however not sufficient so as to induce weight loss. Most importantly, ASA was able to improve insulin resistance. Gene expression profiles of pro- and anti-inflammatory cytokines as well as the expression of macrophage and lymphocyte markers revealed that HFD led to a marked macrophage accumulation in the adipose tissue and an increase of several pro-inflammatory cytokines, a situation almost completely reverted after ASA administration. In addition, liver steatosis caused by HFD was completely abrogated by ASA treatment.

SIGNIFICANCE

ASA can efficiently ameliorate pathological conditions usually associated with obesity by inhibiting the inflammatory process occurring in the adipose tissue.

Transketolase Deficiency in Adipose Tissues Protects Mice From Diet-Induced Obesity by Promoting Lipolysis

Obesity has recently become a prevalent health threat worldwide. Although emerging evidence has suggested a strong link between the pentose phosphate pathway (PPP) and obesity, the role of transketolase (TKT), an enzyme in the nonoxidative branch of the PPP that connects PPP and glycolysis, remains obscure in adipose tissues. In this study, we specifically deleted TKT in mouse adipocytes and found no obvious phenotype upon normal diet feeding. However, adipocyte TKT abrogation attenuated high-fat diet-induced obesity, reduced hepatic steatosis, improved glucose tolerance, alleviated insulin resistance, and increased energy expenditure. Mechanistically, TKT deficiency accumulated nonoxidative PPP metabolites and decreased glycolysis and pyruvate input into the mitochondria, leading to increased lipolytic enzyme gene expression and enhanced lipolysis, fatty acid oxidation, and mitochondrial respiration. Therefore, our data not only identify a novel role of TKT in regulating lipolysis and obesity but also suggest that limiting glucose-derived carbon into the mitochondria induces lipid catabolism and energy expenditure.

Aspirin Modifies Inflammatory Mediators and Metabolomic Profiles and Contributes to the Suppression of Obesity-Associated Breast Cancer Cell Growth

Breast cancer is the most common cancer among women. Adiposity generally accompanies immune cell infiltration and cytokine secretion, which is ideal for tumor development. Aspirin is a chemopreventive agent against several types of cancer. The aim of this study was to investigate whether aspirin inhibits the growth of 4T1 breast cancer cells by inhibiting the inflammatory response and regulating the metabolomic profile of 3T3-L1 adipocytes. 3T3-L1 adipocyte-conditioned medium (Ad-CM) was used to mimic the obese adipose tissue microenvironment in 4T1 cells. The results revealed that aspirin inhibited macrophage chemoattractant protein (MCP-1), interleukin (IL-6), IL-1β, and plasminogen activator inhibitor (PAI-1) production in 3T3-L1 adipocytes stimulated by tumor necrosis factor-alpha (TNF-α) and lipopolysaccharide (LPS). In the obesity-associated model, Ad-CM significantly promoted 4T1 cell growth and migration, which were attenuated after aspirin treatment. The results of metabolic analyses using Ad-CM showed that amino acid metabolites and oxidative stress were increased in mature 3T3-L1 adipocytes compared to those in fibroblasts. Aspirin treatment modified metabolites involved in suppressing lipogenesis, oxidative stress, and neoplastic formation. In the relative fatty acid quantitation analysis of Ad-CM, aspirin diminished fatty acid contents of C16:1, C18:1, C18:2, C20:4, and C24:1. This study is the first to show that aspirin modifies the metabolomics and fatty acid composition of 3T3-L1 adipocytes and inhibits obesity-associated inflammation that contributes to obesity-related breast cancer cell growth and migration.

Chronic Intermittent Hypoxia Triggers a Senescence-like Phenotype in Human White Preadipocytes

Obstructive sleep apnea (OSA) is a common sleep disorder associated with obesity. Emerging evidence suggest that OSA increases the risk of cardiovascular morbidity and mortality partly via accelerating the process of cellular aging. Thus, we sought to examine the effects of intermittent hypoxia (IH), a hallmark of OSA, on senescence in human white preadipocytes. We demonstrate that chronic IH is associated with an increased generation of mitochondrial reactive oxygen species along with increased prevalence of cells with nuclear localization of γH2AX & p16. A higher prevalence of cells positive for senescence-associated β-galactosidase activity was also evident with chronic IH exposure. Intervention with aspirin, atorvastatin or renin-angiotensin system (RAS) inhibitors effectively attenuated IH-mediated senescence-like phenotype. Importantly, the validity of in vitro findings was confirmed by examination of the subcutaneous abdominal adipose tissue which showed that OSA patients had a significantly higher percentage of cells with nuclear localization of γH2AX & p16 than non-OSA individuals (20.1 ± 10.8% vs. 10.3 ± 2.7%, Padjusted < 0.001). Furthermore, the frequency of dual positive γH2AX & p16 nuclei in adipose tissue of OSA patients receiving statin, aspirin, and/or RAS inhibitors was comparable to non-OSA individuals. This study identifies chronic IH as a trigger of senescence-like phenotype in preadipocytes. Together, our data suggest that OSA may be considered as a senescence-related disorder.

Aspirin Mitigated Tumor Growth in Obese Mice Involving Metabolic Inhibition

Obesity is associated with a wide range of chronic diseases, including cancer. It has been noted that the integration of metabolic mechanisms in obese patients may predispose them to suffer from cancer incidence and its progression. Thus, a better understanding of metabolic alterations in obesity, along with the development of feasible therapeutic approaches for intervention, are theoretically relevant to the prevention and treatment of cancer malignancy. Using a syngeneic tumor model involving Lewis Lung Carcinoma (LLC) cells and C57BL/6 mice fed with a high fat diet, obesity was found to be associated with dysregulated glucose and glutamine metabolism, inflammation, along with platelet activation and the promotion of tumor growth. Tumor-bearing lowered glucose levels while moderately increasing inflammation, platelet activation, and glutamine levels. The antiplatelet drug aspirin, mitigated tumor growth in obese mice, paralleled by a decrease in systemic glucose, insulin, inflammation, platelet activation, glutamine and tumor expression of cell proliferation, aerobic glycolysis, glutaminolysis, platelets, and leukocyte molecules. The anti- and pro-cell proliferation, aerobic glycolysis, and glutaminolysis effects of aspirin and glutamine were further demonstrated in a LLC cell study. Although there remains limitations to our experiments, glucose and glutamine metabolism are proposed targets for the anticancer effects of aspirin.

Untargeted Metabolomics to Go beyond the Canonical Effect of Acetylsalicylic Acid

Given to its ability to irreversibly acetylate the platelet cyclooxygenase-1 enzyme, acetylsalicylic acid (ASA) is successfully employed for the prevention of cardiovascular disease. Recently, an antitumoral effect of ASA in colorectal cancer has been increasingly documented. However, the molecular and metabolic mechanisms by which ASA exerts such effect is largely unknown. Using a new, untargeted liquid chromatography–mass spectrometry approach, we have analyzed urine samples from seven healthy participants that each ingested 100 mg of ASA once daily for 1 week. Of the 2007 features detected, 25 metabolites differing after ASA ingestion (nominal p < 0.05 and variable importance in projection (VIP) score > 1) were identified, and pathway analysis revealed low levels of glutamine and of metabolites involved in histidine and purine metabolisms. Likewise, consistent with an altered fatty acid β-oxidation process, a decrease in several short- and medium-chain acyl-carnitines was observed. An abnormal β-oxidation and a lower than normal glutamine availability suggests reduced synthesis of acetyl-Co-A, as they are events linked to one another and experimentally related to ASA antiproliferative effects. While giving an example of how untargeted metabolomics allows us to explore new clinical applications of drugs, the present data provide a direction to be pursued to test the therapeutic effects of ASA—e.g., the antitumoral effect—beyond cardiovascular protection.

Aspirin Breaks the Crosstalk between 3T3-L1 Adipocytes and 4T1 Breast Cancer Cells by Regulating Cytokine Production

Breast cancer is one of the most common cancers in women worldwide. The obesity process is normally accompanied by chronic, low-grade inflammation. Infiltration by inflammatory cytokines and immune cells provides a favorable microenvironment for tumor growth, migration, and metastasis. Epidemiological evidence has shown that aspirin is an effective agent against several types of cancer. The aim of this study is to investigate the anti-inflammatory and anti-cancer effects of aspirin on 3T3-L1 adipocytes, 4T1 murine breast cancer cells, and their crosstalk. The results showed that aspirin treatment inhibited differentiation and lipid accumulation by 3T3-L1 preadipocytes, and decreased the secretion of the inflammatory adipokine MCP-1 after stimulation with tumor necrosis factor (TNF)-α or conditioned medium from RAW264.7 cells. In 4T1 cells, treatment with aspirin decreased cell viability and migration, possibly by suppressing MCP-1 and VEGF secretion. Subsequently, culture of 4T1 cells in 3T3-L1 adipocyte-conditioned medium (Ad-CM) and co-culture of 3T3-L1 and 4T1 cells using a transwell plate were performed to clarify the relationship between these two cell lines. Aspirin exerted its inhibitory effects in the transwell co-culture system, as well as the conditioned-medium model. Aspirin treatment significantly inhibited the proliferation of 4T1 cells, and decreased the production of MCP-1 and PAI-1 in both the Ad-CM model and co-culture system. Aspirin inhibited inflammatory MCP-1 adipokine production by 3T3-L1 adipocytes and the cell growth and migration of 4T1 cells. It also broke the crosstalk between these two cell lines, possibly contributing to its chemopreventive properties in breast cancer. This is the first report that aspirin’s chemopreventive activity supports the potential application in auxiliary therapy against obesity-related breast cancer development.

Redox modulation of adipocyte differentiation: hypothesis of "Redox Chain" and novel insights into intervention of adipogenesis and obesity

In view of the global prevalence of obesity and obesity-associated disorders, it is important to clearly understand how adipose tissue forms. Accumulating data from various laboratories implicate that redox status is closely associated with energy metabolism. Thus, biochemical regulation of the redox system may be an attractive alternative for the treatment of obesity-related disorders. In this work, we will review the current data detailing the role of the redox system in adipocyte differentiation, as well as identifying areas for further research. The redox system affects adipogenic differentiation in an extensive way. We propose that there is a complex and interactive "redox chain," consisting of a "ROS-generating enzyme chain," "combined antioxidant chain," and "transcription factor chain," which contributes to fine-tune the regulation of ROS level and subsequent biological consequences. The roles of the redox system in adipocyte differentiation are paradoxical. The redox system exerts a "tridimensional" mechanism in the regulation of adipocyte differentiation, including transcriptional, epigenetic, and posttranslational modulations. We suggest that redoxomic techniques should be extensively applied to understand the biological effects of redox alterations in a more integrated way. A stable and standardized "redox index" is urgently needed for the evaluation of the general redox status. Therefore, more effort should be made to establish and maintain a general redox balance rather than to conduct simple prooxidant or antioxidant interventions, which have comprehensive implications.