From fat cells through an obesity theory

Effects of Flavanone Derivatives on Adipocyte Differentiation and Lipid Accumulation in 3T3-L1 Cells

Flavanones, a class of flavonoids, are abundant in fruits, vegetables, and herbs. They are known to have several biological activities, such as anti-inflammatory and anti-cancer activities, but their effects on obesity remain unclear. Obesity is closely associated with adipocyte differentiation and lipid accumulation in adipose tissue. Therefore, in this study, we examined the effects of flavanone derivatives on adipocyte differentiation and lipid accumulation by using 3T3-L1 cells. Among the 15 flavanone derivatives studied, 4'-phenylflavanone (4PF), with a biphenyl structure, significantly inhibited adipocyte differentiation-related lipid accumulation in 3T3-L1 cells; this inhibition of lipid accumulation was dose-dependent. Gene expression analysis showed that 4PF suppressed the expression of adipogenic marker genes. Although the induction of peroxisome proliferator activator γ2 (Pparγ2), a master regulator of adipocyte differentiation, and its target genes during adipocyte differentiation was attenuated in 4PF-treated cells, 4PF did not directly regulate Pparγ2 gene expression and its activation. In contrast, 4PF suppressed mitotic clonal expansion (MCE), which is associated with changes in the expression of proliferation-related genes at the early stages of adipocyte differentiation. Taken together, these results suggest that 4PF inhibits lipid accumulation because it suppresses MCE during adipocyte differentiation. Thus, our findings may help in the development of anti-obesity drugs.

Insoluble Dietary Fiber from Soybean Residue (Okara) Exerts Anti-Obesity Effects by Promoting Hepatic Mitochondrial Fatty Acid Oxidation

Numerous investigations have shown that insoluble dietary fiber (IDF) has a potentially positive effect on obesity due to a high-fat diet (HFD). Our previous findings based on proteomic data revealed that high-purity IDF from soybean residue (okara) (HPSIDF) prevented obesity by regulating hepatic fatty acid synthesis and degradation pathways, while its intervention mechanism is uncharted. Consequently, the goal of this work is to find out the potential regulatory mechanisms of HPSIDF on hepatic fatty acid oxidation by determining changes in fatty acid oxidation-related enzymes in mitochondria and peroxisomes, the production of oxidation intermediates and final products, the composition and content of fatty acids, and the expression levels of fatty acid oxidation-related proteins in mice fed with HFD. We found that supplementation with HPSIDF significantly ameliorated body weight gain, fat accumulation, dyslipidemia, and hepatic steatosis caused by HFD. Importantly, HPSIDF intervention promotes medium- and long-chain fatty acid oxidation in hepatic mitochondria by improving the contents of acyl-coenzyme A oxidase 1 (ACOX1), malonyl coenzyme A (Malonyl CoA), acetyl coenzyme A synthase (ACS), acetyl coenzyme A carboxylase (ACC), and carnitine palmitoyl transferase-1 (CPT-1). Moreover, HPSIDF effectively regulated the expression levels of proteins involved with hepatic fatty acid β-oxidation. Our study indicated that HPSIDF treatment prevents obesity by promoting hepatic mitochondrial fatty acid oxidation.

D-Limonene Promotes Anti-Obesity in 3T3-L1 Adipocytes and High-Calorie Diet-Induced Obese Rats by Activating the AMPK Signaling Pathway

D-limonene (LIM) is a common monoterpene compound, principally found in citrus essential oils. This study investigated the anti-obesity effect of LIM on the 5′-adenosine monophosphate (AMP)-activated protein kinase (AMPK) signaling pathway in 3T3-L1 adipocytes and high-calorie diet-induced obese rats and confirmed the optimally effective dose of LIM. The 3T3-L1 adipocytes were treated with 0.05−0.4 mg/mL LIM for 10 days and oil red O and triglyceride (TG) content were used to determine the levels of lipid accumulation. The results showed that more than 0.05 mg/mL LIM inhibited lipid accumulation by reducing oil red O in 3T3-L1 adipocytes. Masses of 0.2 and 0.4 mg/mL LIM also decreased the TG contents in 3T3-L1 adipocytes. On the other hand, Wistar rats were given high-calorie diets, combined with LLIM (154 mg/kg) and HLIM (1000 mg/kg) treatments, for 16 weeks. The result shows that LLIM and HLIM decreased body weight, total fat tissue weight, and serum low-density lipoprotein-cholesterol (LDLc) levels. HLIM reduced serum TG and increased serum lipase and high-density lipoprotein-cholesterol (HDLc) levels. Moreover, the anti-obesity metabolic pathway showed that LIM (>0.05 mg/mL) in 3T3-L1 adipocytes and LIM (>154 mg/kg) in high-calorie diet-induced obese rats could activate the AMPK signaling pathway. The activated AMPK regulated the mRNA expression related to adipogenesis (PPARγ, C/EBPα, FABP4), lipogenesis (SREBP-1c, ACC, FAS), and lipolysis (ATGL, HSL) to inhibit obesity. This finding demonstrates that LIM has anti-obesity properties. Namely, it is seen that LIM acts by regulating the AMPK signaling pathway in 3T3-L1 adipocytes and high-calorie diet-induced obese rats. In terms of dose−response, LIM (154 mg/kg) would be an optimal effective dose for anti-obesity induced by a high-calorie diet.

Spiraea prunifolia leaves extract inhibits adipogenesis and lipogenesis by promoting β-oxidation in high fat diet-induced obese mice

Spiraea prunifolia has been used in Korean traditional medicine to treat malaria, fever, and emetic conditions. Previous investigation reported that several parts of Spiraea prunifolia show various functional effects. However, the effect of Spiraea prunifolia leaves extract (SPE) on anti-obesity remains unclear. Therefore, we used a high-fat diet (HFD)-induced obese mouse model in this study to investigate the effects of SPE on adipogenesis, lipogenesis, and β-oxidation. Oral administration of SPE in HFD-induced obese mice considerably reduced body weight, serum levels such as total cholesterol, triglyceride, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol, adipose tissue weight, and adipocyte cell size. Moreover, SPE significantly decreased protein expression levels of adipogenesis and lipogenesis related genes such as CCAAT/enhancer binding protein α, peroxisome proliferator-activated receptor γ, adipocyte protein 2, acetyl-CoA carboxylase, and fatty acid synthase in epididymal adipose tissues. SPE treatment induced the protein expression of carnitine palmitoyl transferase-1, which might have promoted phosphorylated AMP-activated protein kinase-medicated β-oxidation. The present study reveals an anti-adipogenic, anti-lipogenic, β-oxidation effects of SPE in vivo and represents AMP-activated protein kinase signaling as targets for SPE.

Chebulinic Acid Suppresses Adipogenesis in 3T3-L1 Preadipocytes by Inhibiting PPP1CB Activity

Depletion of protein phosphatase-1 catalytic subunit beta (PPP1CB), a serine/threonine protein phosphatase and potent adipogenic activator, suppresses the differentiation of 3T3-L1 preadipocytes into mature adipocytes. Therefore, PPP1CB is considered as a potential therapeutic target for obesity. We screened 1033 natural products for PPP1CB inhibitors and identified chebulinic acid, which is abundantly present in the seeds of Euphoria longana and fruits of Terminalia chebula. Chebulinic acid strongly inhibited the hydrolysis of 6,8-difluoro-4-methylumbelliferyl phosphate by PPP1CB (IC₅₀ = 300 nM) and demonstrated potent antiadipogenic effects in 3T3-L1 preadipocytes in a concentration-dependent manner. Additional studies have demonstrated that chebulinic acid suppresses early differentiation by downregulating key transcription factors that control adipogenesis in 3T3-L1 cells. These results suggested that chebulinic acid may be a potential therapeutic agent for treating obesity by inhibiting PPP1CB activity.

"Selected Papers from the 2nd Ellisras Longitudinal Study and Other Non-Communicable Diseases Studies International Conference" Special Issue Editorial

Epidemics of non-communicable diseases (NCDs) are presently emerging and on the increase in South Africa. It is increasingly recognized that the occurrence of adult chronic disease are influenced by factors operating from childhood, which are sustained throughout the individual’s life course. Increased risk may start in infancy or even before birth and will continue to be influenced by health related behavior during adulthood. The academic level of people in the community influence the level of their health status. Commitment to the promotion of health through prevention, education, and suitable management is the building block for creating a healthy society. The community must make strides to shift from traditional knowledge and medication, and seek new innovative ways of addressing issues facing the population with regard to obesity, overweight, hypertension health, smoking cessation, alcohol abuse, and low physical activity in line with a healthy living lifestyle. The NCDs pose health problems in South Africa and deserve more attention. Poor control of obesity, hypertension, and diabetes, to name just a few, only adds to the current problems. The South African government and the business sector of South Africa should provide safe walking/riding trails in the cities and in rural area to combat emerging NCDs that are killing our community members indiscriminately without considering race, gender, age, and place of residence. Compulsory introduction of physical education lessons to all public schools cannot be over emphasized in the current escalating NCD situation in South Africa.

The Genetic Basis of Obesity and Related Metabolic Diseases in Humans and Companion Animals

Obesity is one of the most prevalent health conditions in humans and companion animals globally. It is associated with premature mortality, metabolic dysfunction, and multiple health conditions across species. Obesity is, therefore, of importance in the fields of medicine and veterinary medicine. The regulation of adiposity is a homeostatic process vulnerable to disruption by a multitude of genetic and environmental factors. It is well established that the heritability of obesity is high in humans and laboratory animals, with ample evidence that the same is true in companion animals. In this review, we provide an overview of how genes link to obesity in humans, drawing on a wealth of information from laboratory animal models, and summarise the mechanisms by which obesity causes related disease. Throughout, we focus on how large-scale human studies and niche investigations of rare mutations in severely affected patients have improved our understanding of obesity biology and can inform our ability to interpret results of animal studies. For dogs, cats, and horses, we compare the similarities in obesity pathophysiology to humans and review the genetic studies that have been previously reported in those species. Finally, we discuss how veterinary genetics may learn from humans about studying precise, nuanced phenotypes and implementing large-scale studies, but also how veterinary studies may be able to look past clinical findings to mechanistic ones and demonstrate translational benefits to human research.

Efficacy and Safety of Combined Extracts of Cornus officinalis and Ribes fasciculatum for Body Fat Reduction in Overweight Women

Obesity is a medical condition that presents excessive fat accumulation with high risk of serious chronic diseases. The aim of this clinical trial is to investigate the anti-obesity effects of Cornus officinalis (CO) and Ribes fasciculatum (RF) on body fat reduction in Korean overweight women. A total of 147 overweight female participants enrolled in double-blinded clinical trial for 12 weeks and 76 participants completed the clinical study. Participants were treated with four CO and RF mixture (COEC; 400 mg per tablet) or four placebo tablets once a day. Obesity associated parameters (body weight, body mass index (BMI), waist circumference, waist-to-hip ratio, body fat percentage and body fat mass) and safety assessment were analyzed. After 12 weeks of COEC treatment, primary outcomes such as body fat percentage (0.76% vs. 0.01%; p = 0.022) and mass (1.1 kg vs. 0.5 kg; p = 0.049) were significantly decreased. In addition, the results were statistically significant between the COEC and placebo groups, strongly indicated that COEC had anti-obesity effects on overweight women. Secondary outcomes—including body weight, waist and hip circumference, waist-to-hip ratio, body mass index and computed tomography measurement of visceral fat area, subcutaneous fat area, total abdominal fat area and visceral-to-subcutaneous fat ratio—were reduced in COEC-treated group, but no statistical differences were found between the COEC and placebo groups. The safety assessment did not differ between the two groups. These results suggest that treatment of COEC extract reduces body fat percentage and mass in Korean overweight women, indicating it as a protective functional agent for obesity.

Antiobesity Effects of Gentiana lutea Extract on 3T3-L1 Preadipocytes and a High-Fat Diet-Induced Mouse Model

Obesity is one of the most common metabolic diseases resulting in metabolic syndrome. In this study, we investigated the antiobesity effect of Gentiana lutea L. (GL) extract on 3T3-L1 preadipocytes and a high-fat-diet (HFD)-induced mouse model. For the induction of preadipocytes into adipocytes, 3T3-L1 cells were induced by treatment with 0.5 mM 3-isobutyl-1-methylxanthine, 1 mM dexamethasone, and 1 μg/mL insulin. Adipogenesis was assessed based on the messenger ribonucleic acid expression of adipogenic-inducing genes (adiponectin (Adipoq), CCAAT/enhancer-binding protein alpha (Cebpa), and glucose transporter type 4 (Slc2a4)) and lipid accumulation in the differentiated adipocytes was visualized by Oil Red O staining. In vivo, obese mice were induced with HFD and coadministered with 100 or 200 mg/kg/day of GL extract for 12 weeks. GL extract treatment inhibited adipocyte differentiation by downregulating the expression of adipogenic-related genes in 3T3-L1 cells. In the obese mouse model, GL extract prevented HFD-induced weight gain, fatty hepatocyte deposition, and adipocyte size by decreasing the secretion of leptin and insulin. In conclusion, GL extract shows antiobesity effects in vitro and in vivo, suggesting that this extract can be beneficial in the prevention of obesity.

Ginsenoside Rg2 inhibits adipogenesis in 3T3-L1 preadipocytes and suppresses obesity in high-fat-diet-induced obese mice through the AMPK pathway

Rg2-induced activation of AMPK reduced the expression of adipogenic transcription factors, and regulated the lipogenic and lipolysis genes, thus inhibiting adipogenesis.