Indomethacin Enhances Brown Fat Activity

Optimization of differentiation conditions for porcine adipose-derived mesenchymal stem cells and analysis of fatty acids in cultured fat

Cultured fat is an important part of cultured meat, and the ability of adipose-derived mesenchymal stem cells (ADSCs) to differentiate into mature adipose tissue affects the quality of cultured fat. Thus, the primary aim of this study was to screen for combinations of differentiation-inducing factors (DIF) using single-factor experiment and orthogonal experimental design under two-dimensional culture conditions for ADSCs. The results showed that a combination of DIF consisting of 1 μmol/L dexamethasone, 0.1 mmol/L 3-isobutyl-1-methylxanthine, 10 μg/mL insulin, 0.1 mmol/L indomethacin, and 2 μmol/L rosiglitazone was a good choice for the differentiation of ADSCs. An combination of DIF was applied to the preparation of cultured fat with collagen as scaffolds. Forty-eight fatty acids were detected in cultured fat by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Among them, the content of twenty-one fatty acids in cultured fat was significantly higher than that of conventional porcine subcutaneous adipose tissue (P < 0.05), and the content of 14 fatty acids was not significantly different (P > 0.05). The ratio of ω-6 polyunsaturated fatty acids content to ω-3 polyunsaturated fatty acids content was 1.23:1, which meant cultured fat was beneficial for human health. This study provides a method to improve the differentiation ability of ADSCs while also providing a reference for indicating the nutritional value of cultured fat.

Food phenolics stimulate adipocyte browning via regulating gut microecology

Fat browning has piqued the interest of researchers as a potential target for treating obesity and related metabolic disorders. Recruitment of brown adipocytes leads to enhanced energy dissipation and reduced adiposity, thus facilitating the maintenance of metabolic homeostasis. Evidence is increasing to support the crucial roles of polyphenols and gut microecology in turning fat "brown". However, it is not clear whether the intestinal microecology is involved in polyphenol-mediated regulation of adipose browning, so this concept is worthy of exploration. In this review, we summarize the current knowledge, mostly from studies with murine models, supporting the concept that the effects of food phenolics on brown fat activation and white fat browning can be attributed to their regulatory actions on gut microecology, including microbial community profile, gut metabolites, and gut-derived hormones. Furthermore, the potential underlying pathways involved are also discussed. Basically, understanding gut microecology paves the way to determine the underlying roles and mechanisms of food phenolics in adipose browning.

Lysine reactivity profiling reveals molecular insights into human serum albumin-small-molecule drug interactions

Human serum albumin (HSA) is one of the most important serum carrier proteins that deliver small-molecule drugs to their specific targets. Clarifying the molecular mechanism of the interaction between natural HSA and drugs in an aqueous solution has been a hot topic in pharmaceutical chemistry, clinical medicine, and biochemistry in recent years, but it is still challenging. In this paper, the details of molecular interactions of HSA with a variety of therapeutic drugs including ibuprofen, indomethacin, phenylbutazone, and warfarin are systematically investigated using a mass spectrometry (MS)-based lysine reactivity profiling (LRP) strategy. The results reaffirm that the major ligand binding sites (including Sites I and II) of HSA are located in subdomains IIA and IIIA, while several potential drug-binding areas at subdomain IIIB and α helix IIB-IIIA are newly characterized. The MS-LRP strategy may have important application prospects in pharmacodynamics, pharmacokinetics, and safety evaluation of small-molecule drugs.

Regulatory T cells promote adipocyte beiging in subcutaneous adipose tissue

Regulatory T cells (Tregs) play essential roles in obesity and diabetes. Here, we report a role of Tregs in enhancing β3-adrenergic receptor agonist CL316243 (CL)-stimulated thermogenic program in subcutaneous adipose tissue (SAT), but not in visceral fat. CL treatment for 7 days increased SAT adipocyte beiging and thermogenic gene expression in male or female mice. Adoptive transfer of Tregs enhanced this CL activity. Such Treg activity lost in male epididymal white adipose tissue (eWAT) and female gonadal gWAT. Adipocyte culture yielded the same conclusion. Tregs enhanced the expression of CL-induced thermogenic genes in SAT from male and female mice. This activity of Tregs reduced or disappeared in adipocytes from eWAT or gWAT. Both CL and Tregs induced much higher UCP-1 (uncoupling protein-1) expression in SAT from females than that from males. A mechanistic study demonstrated a role of Tregs in suppressing the expression of M1 macrophage markers (Tnfa, Il6, iNos, Ip10) and promoting the expression of M2 macrophage markers (Mrc1, Arg1, Il10) in bone-marrow-derived macrophages or in SAT from male or female mice. In female mice with pre-established obesity, Treg adoptive transfer reduced the gWAT weight in 2 weeks. Together with CL treatment, Treg adoptive transfer reduced the SAT weight and further improved CL-induced glucose metabolism and insulin sensitivity in female obese mice, but did not affect CL-induced body weight loss in male or female obese mice. This study revealed a predominant role of Tregs in female mice in promoting adipocyte beiging and thermogenesis in SAT, in part by slanting M2 macrophage polarization.

Indomethacin promotes browning and brown adipogenesis in both murine and human fat cells

Indomethacin (Indo), a nonsteroidal antiinflammatory drug, has been shown to promote murine brown adipogenesis both in vitro and in vivo, possibly due to its peroxisome proliferator-activated receptor gamma (PPARγ)-agonist activities. However, it is unclear whether Indo induces browning of white adipocytes from both murine and human origins or induces human brown adipogenesis. To bridge the gap, this study investigated the effects of increasing concentrations of Indo on murine 3T3-L1, human primary subcutaneous white adipocytes (HPsubQ), and human brown (HBr) adipocytes. The results show that Indo dose-dependently enhanced 3T3-L1 adipocyte differentiation and upregulated both mRNA and protein expression of brown and beige adipocyte markers, while simultaneously suppressing white adipocyte-specific marker mRNA expression. mRNA and protein expression of mitochondrial biogenesis and structural genes were dose-dependently enhanced in Indo treated 3T3-L1 adipocytes. This was accompanied by augmented mitochondrial DNA, enhanced oxygen consumption, proton leak, and maximal and spare respiratory capacity. Dose-dependent transactivation of PPARγ confirmed Indo's PPARγ-agonist activity in 3T3-L1 cells. Knockdown of PPARγ significantly attenuated Indo's activities in selective browning genes, demonstrating PPARγ dependence of these effects. Moreover, Indo enhanced mRNA and protein expression of brown markers in HPsubQ adipocytes. Interestingly, Indo-induced differential effects on individual PPARγ isoforms with significant dose-dependent induction of PPARγ-2 and suppression of PPARγ-1 protein expression. Finally, Indo significantly promoted brown adipogenesis in HBr cells. Taken together, these results demonstrate Indo to be a potent thermogenic compound in both murine and human fat cells and may be explored as a therapeutic agent for obesity treatment and prevention.

Adiponectin and PPAR: a setup for intricate crosstalk between obesity and non-alcoholic fatty liver disease

Adiponectin, a soluble adipocytokine, plays an important role in the functioning of adipose tissue and in the regulation of inflammation, particularly hepatic inflammation. The adiponectin subsequently imparts a crucial role in metabolic and hepato-inflammatory diseases. The most recent evidences indicate that lipotoxicity-induced inflammation in the liver is associated with obesity-derived alterations and remolding in adipose tissue that culminates in most prevalent liver pathology named as non-alcoholic fatty liver disease (NAFLD). A comprehensive crosstalk of adiponectin and its cognate receptors, specifically adiponectin receptor-2 in the liver mediates ameliorative effects in obesity-induced NAFLD by interaction with hepatic peroxisome proliferator-activated receptors (PPARs). Recent studies highlight the implication of molecular mediators mainly involved in the pathogenesis of obesity and obesity-driven NAFLD, however, the plausible mechanisms remain elusive. The present review aimed at collating the data regarding mechanistic approaches of adiponectin and adiponectin-activated PPARs as well as PPAR-induced adiponectin levels in attenuation of hepatic lipoinflammation. Understanding the rapidly occurring adiponectin-mediated pathophysiological outcomes might be of importance in the development of new therapies that can potentially resolve obesity and obesity-associated NAFLD.

Beneficial Metabolic Effects of Mirabegron In Vitro and in High-Fat Diet-Induced Obese Mice

Mirabegron, a β3-adrenergic receptor agonist, has been shown to stimulate the activity of brown fat and increase the resting metabolic rate in humans. However, it is unknown whether mirabegron can reduce body weight and improve metabolic health. We investigated the antiobesity effects of mirabegron using both in vitro and in vivo models. Mouse brown preadipocytes and 3T3-L1 cells were treated with different concentrations of mirabegron (0.03-3 µg/ml), and the expression of brown fat-related genes was measured by quantitative real-time polymerase chain reaction. Furthermore, male C57BL/6J mice were fed a high-fat diet for 10 weeks, and mirabegron (2 mg/kg body weight) or a vehicle control was delivered to the interscapular brown adipose tissue (iBAT) using ALZET osmotic pumps from week 7 to 10. The metabolic parameters and tissues were analyzed. In both mouse brown preadipocytes and 3T3-L1 cells, mirabegron stimulated uncoupling protein 1 (UCP1) expression. In animal studies, mirabegron-treated mice had a lower body weight and adiposity. Lipid droplets in the iBAT of mirabegron-treated mice were fewer and smaller in size compared with those from vehicle-treated mice. H&E staining and immunohistochemistry indicated that mirabegron increased the abundance of beige cells in inguinal white adipose tissue (iWAT). Compared with vehicle-treated mice, mirabegron-treated mice had a higher gene expression of UCP1 (14-fold) and cell death-inducing DNA fragmentation factor alpha-like effector A (CIDEA) (4-fold) in iWAT. Furthermore, mirabegron-treated mice had improved glucose tolerance and insulin sensitivity. Taken together, mirabegron enhances UCP1 expression and promotes browning of iWAT, which are accompanied by improved glucose tolerance and insulin sensitivity and prevention from high-fat diet-induced obesity.

Screening of FDA-approved drugs identifies sutent as a modulator of UCP1 expression in brown adipose tissue

BACKGROUND

The pharmacological activation of thermogenesis in brown adipose tissue has long been considered promising strategies to treat obesity. However, identification of safe and effective agents remains a challenge. In this study, we addressed this challenge by developing a cellular system with a fluorescence readout, and applied in a high-throughput manner to screen for FDA-approved drugs that may activate endogenous UCP1 expression in adipocytes.

METHODS

We have generated a Ucp1-2A-GFP reporter mouse, in which GFP intensity serves as a surrogate of the endogenous expression level of UCP1 protein; and immortalized brown adipocytes were derived from this mouse model and applied in drug screening. Candidate drugs were further tested in mouse models either fed with normal chow or high fat diet to induce obesity.

FINDINGS

By using the cellular screening platform, we identified a group of FDA-approved drugs that can upregulate UCP1 expression in brown adipocyte, including previously known UCP1 activators and new candidate drugs. Further studies focusing on a previously unreported drug-sutent, revealed that sutent treatment could increase the energy expenditure and inhibit lipid synthesis in mouse adipose and liver tissues, resulting in improved metabolism and resistance to obesity.

INTERPRETATION

This study offered an easy-to-use cellular screening system for UCP1 activators, and provided a candidate list of FDA-approved drugs that can potentially treat obesity. Further study of these candidates may shed new light on the drug discovery towards obesity. FUND: National Key Research and Development Program and the Strategic Priority Research Program of the Chinese Academy of Sciences, etc. (250 words).

Determination of potential oxidative damage, hepatotoxicity, and cytogenotoxicity in male Wistar rats: Role of indomethacin

The present study demonstrated the indomethacin (INDO) induced oxidative stress, hepatotoxicity, and genotoxicity in male Wistar rats. Animals were orally administrated INDO at doses of 0.302 and 0.605 (mg/kg b.w.) for 2 weeks. Reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), and lipid peroxidation (LPO) activities/levels were measured in the liver, kidney, and brain tissues. The aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) activities, total bilirubin (TBIL) levels, and histopathological changes were determined in the liver tissues. Micronucleus frequency (micronucleus test) and DNA damage (comet assay) tests were performed in the bone marrow cells and leukocytes, respectively. Results show that INDO treatment decreased the GSH, SOD, and CAT levels/activities and increased the LPO, ALT, AST, ALP, and TBIL activities/levels. INDO induced significant hepatic injury and micronucleus and DNA damage. Thus, the current investigations confirm the oxidative stress, hepatotoxic, and genotoxic properties of INDO in the male Wistar rats.