Effect of 2'-Fucosyllactose on Beige Adipocyte Formation in 3T3-L1 Adipocytes and C3H10T1/2 Cells

2'-Fucosyllactose (2'-FL), the functional oligosaccharide naturally present in milk, has been shown to exert health benefits. This study was aimed to investigate the effect of 2'-fucosyllactose (2'-FL) on the browning of white adipose tissue in 3T3-L1 adipocytes and C3H10T1/2 cells. The results revealed that 2'-FL decreased lipid accumulations with reduced intracellular triglyceride contents in vitro. 2'-FL intervention increased the mitochondria density and the proportion of UCP1-positive cells. The mRNA expressions of the mitochondrial biogenesis-related and browning markers (Cox7a, Cyto C, Tfam, Ucp1, Pgc1α, Prdm16, Cidea, Elovl3, Pparα, CD137, and Tmem26) were increased after 2'-FL intervention to some extent. Similarly, the protein expression of the browning markers, including UCP1, PGC1α, and PRDM16, was up-regulated in the 2'-FL group. Additionally, an adenosine monophosphate-activated protein kinase (AMPK) inhibitor, compound C (1 μM), significantly decreased the induction of thermogenic proteins expressions mediated by 2'-FL, indicating that the 2'-FL-enhanced beige cell formation was partially dependent on the AMPK pathway. In conclusion, 2'-FL effectively promoted the browning of white adipose in vitro.

WKYMVm ameliorates obesity by improving lipid metabolism and leptin signalling

Obesity is a metabolic disorder that results from an imbalance of energy intake and consumption. As low-grade chronic inflammation caused by obesity can lead to various complications, it is important to develop effective treatments against obesity. In this study, we investigate the effects of WKYMVm, a strong anti-inflammatory agent, against obesity. Administration of WKYMVm into high fat diet (HFD)-induced obese mice significantly attenuated body weight gain, food intake and increased insulin sensitivity. HFD-induced hepatic steatosis and adipose tissue hypertrophy were also markedly ameliorated by WKYMVm. During the maturation of adipocytes, WKYMVm improves lipid metabolism by increasing lipolysis, adipogenesis, mitochondrial biogenesis and fat browning. WKYMVm administration also elicited a decrease in leptin levels, but an increase in leptin sensitivity via regulation of hypothalamic endoplasmic reticulum stress and the leptin receptor cascade. Taken together, our results show that WKYMVm ameliorates obesity by improving lipid metabolism and leptin signalling, suggesting that WKYMVm can be a useful molecule for the development of anti-obesity agents.

Potential Health Benefits of Whole Grains: Modulation of Mitochondrial Biogenesis and Energy Metabolism

Mitochondria play an essential role in maintaining cellular metabolic homeostasis. However, its dysfunction will cause different pathophysiological consequences. A specific mechanism of action has been developed by cells to adapt to changes in physiological conditions or in response to different stimuli, by meditating mitochondrial number, structure, and energy metabolism. Whole grains are considered healthier than refined grains for their higher amounts of bioactive components, with proven multiple health benefits. The modulation of an appropriate mitochondrial function contributes to the bioactive-component-based health improvements. Thus, this review aims to represent current studies that identify the impact of natural bioactive components in whole grains against metabolic disorders by modulating mitochondrial biogenesis and energy metabolism. It seems most attractive to aim nutritional intervention at the prevention or treatment of metabolic abnormalities and hence to target dietary management at improvement of mitochondrial function.

Blueberry Counteracts Prediabetes in a Hypercaloric Diet-Induced Rat Model and Rescues Hepatic Mitochondrial Bioenergetics

The paramount importance of a healthy diet in the prevention of type 2 diabetes is now well recognized. Blueberries (BBs) have been described as attractive functional fruits for this purpose. This study aimed to elucidate the cellular and molecular mechanisms pertaining to the protective impact of blueberry juice (BJ) on prediabetes. Using a hypercaloric diet-induced prediabetic rat model, we evaluated the effects of BJ on glucose, insulin, and lipid profiles; gut microbiota composition; intestinal barrier integrity; and metabolic endotoxemia, as well as on hepatic metabolic surrogates, including several related to mitochondria bioenergetics. BJ supplementation for 14 weeks counteracted diet-evoked metabolic deregulation, improving glucose tolerance, insulin sensitivity, and hypertriglyceridemia, along with systemic and hepatic antioxidant properties, without a significant impact on the gut microbiota composition and related mechanisms. In addition, BJ treatment effectively alleviated hepatic steatosis and mitochondrial dysfunction observed in the prediabetic animals, as suggested by the amelioration of bioenergetics parameters and key targets of inflammation, insulin signaling, ketogenesis, and fatty acids oxidation. In conclusion, the beneficial metabolic impact of BJ in prediabetes may be mainly explained by the rescue of hepatic mitochondrial bioenergetics. These findings pave the way to support the use of BJ in prediabetes to prevent diabetes and its complications.

Inhibitory effect of chloroform extracts from Citrus aurantium L. var. amara Engl. on fat accumulation

BACKGROUND

Excess lipid accumulation can accelerate the development of various metabolic diseases. Blossoms of Citrus aurantium L. var. amara Engl. (CAVA) have been reported to possess inhibitory capacities on lipid deposition. However, the constituents responsible for the observed bioactivity and the underlying mechanisms are still not clearly understood.

PURPOSE

To screen constituents from blossoms of CAVA with inhibitory effects on lipid accumulation and to explore the action mechanism.

METHODS

The chloroform (CHL) extracts are prepared from blossoms of CAVA by fractional extraction and are characterized using LC-MS assay. 3T3-L1 preadipocytes are induced with differentiation medium (DMI) and treated with CHL extracts. High fat diet (HFD)-induced obese mice are further established and administrated with CHL extracts for 12 weeks. Hematoxylin and eosin (HE) staining, Oil Red O staining, ELISA, RT-qPCR, western blot and 16S rRNA gene sequence methods are employed.

RESULTS

14 compounds are identified in CHL extracts and trigonelline hydrochloride, nobiletin and 7-demethylsuberosin are most abundant. CHL extracts treatment significantly inhibit differentiation of 3T3-L1 cells by regulating expression of preadipocyte factor-1 (Pref-1), fatty acid synthase (FAS) and CCAAT/enhancer binding protein α (C/EBPα). CHL extracts intervention also significantly attenuate features of obesity and improved plasma biochemical profiles in HFD-fed mice. HFD-triggered hepatic steatosis and epididymal adipose tissues (EATs) hypertrophy are also reversed by CHL extracts administration through enhancing antioxidant responses and modulating lipogenesis and energy expenditure-related genes and proteins. 16S rRNA gene sequence data further show that CHL extracts enhance the diversity of gut microbiota. CHL extracts at lower concentrations reduce the ratio of Firmicutes to Bacteroidetes and the abundance of Erysipelotrichaceae. CHL extracts at higher doses markedly increase the abundance of Lachnospiraceae.

CONCLUSION

These findings suggest that CHL extracts probably suppress lipid accumulation through inhibiting differentiation of 3T3-L1 cells and attenuating metabolic syndromes in HFD-fed mice.

Remedying the Mitochondria to Cure Human Diseases by Natural Products

Mitochondria are the ‘engine' of cells. Mitochondrial dysfunction is an important mechanism in many human diseases. Many natural products could remedy the mitochondria to alleviate mitochondria-involved diseases. In this review, we summarized the current knowledge of the relationship between the mitochondria and human diseases and the regulation of natural products to the mitochondria. We proposed that the development of mitochondrial regulators/nutrients from natural products to remedy mitochondrial dysfunction represents an attractive strategy for a mitochondria-involved disorder therapy. Moreover, investigating the mitochondrial regulation of natural products can potentiate the in-depth comprehension of the mechanism of action of natural products.

New insights into potential nutritional effects of dietary saponins in protecting against the development of obesity

Excessive energy intake, poor physical exercise and genetics/epigenetics are instrumental for the development of obesity. Because of rapidly emerging evidences related to off-target effects and toxicity of anti-obesity drugs, there is a need to search for more effective and targeted drugs for treatment of obesity. Substantial studies have found the nutritional effects of dietary saponins (bio-detergents) in terms of decreasing the synthesis of lipids, suppressing adipogenesis, inhibiting intestinal absorption of lipids, and promoting fecal excretion of bile acids and triglycerides. Dietary saponin have been approved as potent pancreatic lipase inhibitors, disaccharidase enzyme inhibitors, antagonistic to in vitro lipogenesis and in vivo appetite suppressants, antioxidants, immune-regulators, prevent fatty liver formation, protects epithelial vasculature and regulate body weight. Many dietary saponins, such as sibutramine, morgoside, sessiloside, soysaponin B, and diosgenin, have treatment potential against the development of obesity. Excellent scientific achievements have been developed for a better understanding the mechanism of saponins in preventing obesity.

5-(3',4'-Dihydroxyphenyl)-γ-valerolactone, a metabolite of procyanidins in cacao, suppresses MDI-induced adipogenesis by regulating cell cycle progression through direct inhibition of CDK2/cyclin O

Cacao (Theobroma cacao) has a significant polyphenol content and has been reported to elicit anti-obesity effects. Previous studies have focused on the properties of cacao extract and procyanidins, while the potential mechanisms have not been fully elucidated. Here, we investigated the inhibitory effects of procyanidin metabolites on adipogenic cocktail-induced adipogenesis and lipogenesis in 3T3-L1 preadipocytes. It was observed that 5-(3',4'-dihydroxyphenyl)-γ-valerolactone (DHPV), a major procyanidin metabolite, exhibited the greatest inhibitory effects on adipogenesis and lipogenesis. DHPV dose-dependently reduced the expression levels of proteins involved in adipogenesis including peroxisome proliferator-activated receptor γ (PPAR γ) and CCAT/enhancer-binding protein α (C/EBP α), as well as lipogenesis-related factors such as fatty acid synthase and acetyl-CoA carboxylase. These inhibitory effects were primarily due to G1 phase arrest and the suppression of cell proliferation during mitotic clonal expansion, the early stage of adipogenesis. In an extensive kinase array, DHPV directly suppressed activation of the CDK2/cyclin O complex, and inhibited the phosphorylation of C/EBP β, which is responsible for the induction of PPAR γ and C/EBP α. Taken together, these findings suggest that DHPV is a highly biologically active compound with potential anti-obesity effects and works by inhibiting the intracellular lipid content and cell differentiation.

Zeaxanthin promotes mitochondrial biogenesis and adipocyte browning via AMPKα1 activation

Zeaxanthin (ZEA), a type of oxygenated carotenoid with strong antioxidant activity, has previously been found to exhibit an anti-lipogenesis effect. In the present study, we investigated the effect of ZEA on brown-like adipocyte formation and mitochondrial biogenesis in 3T3-L1 adipocytes. Brown adipocyte-specific markers, mitochondrial biogenesis and oxidative stress, and the involvement of AMP-activated protein kinase (AMPK) α1 were assessed. ZEA treated adipocytes demonstrated a brown-like pattern, with upregulated expression of uncoupling protein 1 (UCP1) and other brown adipocyte markers. In addition, ZEA intervention induced a dramatic increase in mitochondrial DNA (mtDNA) content and in the mRNA levels of genes associated with mitochondrial biogenesis. Furthermore, ZEA attenuated mitochondrial oxidative damage caused by lipid peroxidation in adipocytes, significantly improved the mitochondrial membrane potential (MMP), and scavenged intracellular reactive oxygen species (ROS) and mitochondrial superoxide. Finally, we concluded that AMPKα1 mediated the ZEA-caused inhibition of lipid accumulation and promotion of brown and beige adipocyte-biomarker expression, as the positive effects of ZEA were diminished by Prkaa1 (AMPKα1) knockdown. These findings demonstrated that ZEA promoted the expression of brown and beige adipogenesis markers and mitochondrial biogenesis, which involved AMPKα1 activation, thus contributing to the anti-obesity effects of ZEA.

Cocoa Shell Aqueous Phenolic Extract Preserves Mitochondrial Function and Insulin Sensitivity by Attenuating Inflammation between Macrophages and Adipocytes In Vitro

SCOPE

The aim is to assess the action of an aqueous extract from cocoa shell (CAE) and its main phenolic compounds to prevent the loss of obesity-induced mitochondrial function and insulin sensitivity, targeting inflammation between macrophages-adipocytes in vitro.

METHODS AND RESULTS

CAE (31-500 µg mL^-1 ) inhibits 3T3-L1 adipocytes lipid accumulation and induces browning during differentiation. LPS-stimulated RAW264.7 macrophages show reduced inducible nitric oxide synthase and cyclooxygenase-2 expression and lowered pro-inflammatory cytokine production when treated with CAE and pure phenolics. Inflammatory crosstalk created by stimulating adipocytes with macrophage-conditioned media (CM) is arrested; CAE diminishes tumor necrosis factor-α (67%) and promotes adiponectin secretion (12.3-fold). Mitochondrial function, measured by reactive oxygen species production, mitochondrial content, and activity, is preserved in CM-treated adipocytes through up-regulating peroxisome proliferator-activated receptor gamma coactivator 1-α expression. Increases in insulin receptor (9-fold), phosphoinositide 3-kinase (3-fold), protein kinase B (4-fold) phosphorylation, and a decrease in insulin receptor substrate 1 serine phosphorylation induce increased glucose uptake (34%) and glucose transporter 4 translocation (14-fold) in CM-induced adipocytes.

CONCLUSION

CAE phenolics promote a beige phenotype in adipocytes. Macrophages-adipocytes inflammatory interaction is reduced preventing mitochondrial dysfunction and insulin resistance. For the first time, CAE shows a positive effect on adipogenesis and inflammation-related disorders.

Meta-analysis identifies mitochondrial DNA sequence variants associated with walking speed

Declines in walking speed are associated with a variety of poor health outcomes including disability, comorbidity, and mortality. While genetic factors are putative contributors to variability in walking, few genetic loci have been identified for this trait. We examined the role of mitochondrial genomic variation on walking speed by sequencing the entire mitochondrial DNA (mtDNA). Data were meta-analyzed from 1758 Lifestyle Interventions and Independence for Elders (LIFE) Study and replication data from 730 Health, Aging, and Body Composition (HABC) Study participants with baseline walking speed information. Participants were 69+ years old of diverse racial backgrounds (African, European, and other race/ethnic groups) and had a wide range of mean walking speeds [4-6 m (0.78-1.09 m/s) and 400 m (0.83-1.24 m/s)]. Meta-analysis across studies and racial groups showed that m.12705C>T, ND5 variant was significantly associated (p < 0.0001) with walking speed at both short and long distances. Replication and meta-analysis also identified statistically significant walking speed associations (p < 0.0001) between the m.5460.G>A, ND2 and m.309C>CT, HV2 variants at short and long distances, respectively. All results remained statistically significant after multiple comparisons adjustment for 499 mtDNA variants. The m.12705C>T variant can be traced to the beginnings of human global migration and that cells carrying this variant display altered tRNA expression. Significant pooled effects related to stopping during the long-distance walk test were observed across OXPHOS complexes I (p = 0.0017) and III (p = 0.0048). These results suggest that mtDNA-encoded variants are associated with differences in walking speed among older adults, potentially identifying those at risk of developing mobility impairments.

Effects of Polyphenols on Thermogenesis and Mitochondrial Biogenesis

Obesity is a health problem worldwide, and energy imbalance has been pointed out as one of the main factors responsible for its development. As mitochondria are a key element in energy homeostasis, the development of obesity has been strongly associated with mitochondrial imbalance. Polyphenols are the largest group of phytochemicals, widely distributed in the plant kingdom, abundant in fruits and vegetables, and have been classically described as antioxidants owing to their well-established ability to eliminate free radicals and reactive oxygen species (ROS). During the last decade, however, growing evidence reports the ability of polyphenols to perform several important biological activities in addition to their antioxidant activity. Special attention has been given to the ability of polyphenols to modulate mitochondrial processes. Thus, some polyphenols are now recognized as molecules capable of modulating pathways that regulate mitochondrial biogenesis, ATP synthesis, and thermogenesis, among others. The present review reports the main benefits of polyphenols in modulating mitochondrial processes that favor the regulation of energy expenditure and offer benefits in the management of obesity, especially thermogenesis and mitochondrial biogenesis.

Yerba Mate Stimulates Mitochondrial Biogenesis and Thermogenesis in High-Fat-Diet-Induced Obese Mice

SCOPE

The potential effects of yerba mate (YM) on mitochondrial biogenesis and thermogenesis are evaluated.

METHODS AND RESULTS

The in vitro effects of YM on mitochondrial respiration are assessed in C2C12 cells. The expression of genes related to mitochondrial biogenesis and thermogenesis are analyzed by quantitative PCR. The in vivo experiments are performed on mice fed a high-fat diet (HFD) and treated with YM extract. Indirect calorimetry was performed, and the expression of genes and proteins related to mitochondrial biogenesis, thermogenesis, and de novo lipogenesis is determined by quantitative PCR and western blot. Our in vitro data indicate that YM increases mtDNA copy number as well as mitochondrial spare respiratory capacity and coupling efficiency. The gene expression profile reinforces this evidence, indicating a modulation of genes downstream of Ampk. In vivo, it is found that YM partially prevents diet-induced obesity by increasing energy expenditure and enhancing mitochondrial biogenesis via the AMPK/SIRT1/PGC1α pathway.

CONCLUSIONS

YM stimulates mitochondriogenesis and Ucp expression, leading to an increase in the spare respiratory capacity and energy dissipation. These effects may help to better understand the potential use of YM for obesity treatment.

Antiobesity molecular mechanisms of action: Resveratrol and pterostilbene

Obesity is a current global epidemic that has led to a marked increase in metabolic diseases. However, its treatment remains a challenge. Obesity is a multifactorial disease, which involves the dysfunction of neuropeptides, hormones, and inflammatory adipokines from the brain, gut, and adipose tissue. An understanding of the mechanisms and signal interactions in the crosstalk between organs and tissue in the coordination of whole-body energy metabolism would be helpful to provide therapeutic and putative approaches to the treatment and prevention of obesity and related complications. Resveratrol and pterostilbene are well-known stilbenes that provide various potential benefits to human health. In particular, their potential anti-obesity effects have been proven in numerous cell culture and animal studies. Both compounds act to regulate energy intake, adipocyte life cycle and function, white adipose tissue (WAT) inflammation, energy expenditure, and gut microbiota by targeting multiple molecules and signaling pathways as an intervention for obesity. Although the efficacy of both compounds in humans requires further investigation with respect to their oral bioavailability, promising scientific findings have highlighted their potential as candidates for the treatment of obesity and the improvement of obesity-related metabolic diseases. © 2018 BioFactors, 44(1):50-60, 2018.

Obesity

Excessive fat deposition in obesity has a multifactorial aetiology, but is widely considered the result of disequilibrium between energy intake and expenditure. Despite specific public health policies and individual treatment efforts to combat the obesity epidemic, >2 billion people worldwide are overweight or obese. The central nervous system circuitry, fuel turnover and metabolism as well as adipose tissue homeostasis are important to comprehend excessive weight gain and associated comorbidities. Obesity has a profound impact on quality of life, even in seemingly healthy individuals. Diet, physical activity or exercise and lifestyle changes are the cornerstones of obesity treatment, but medical treatment and bariatric surgery are becoming important. Family history, food environment, cultural preferences, adverse reactions to food, perinatal nutrition, previous or current diseases and physical activity patterns are relevant aspects for the health care professional to consider when treating the individual with obesity. Clinicians and other health care professionals are often ill-equipped to address the important environmental and socioeconomic drivers of the current obesity epidemic. Finally, understanding the epigenetic and genetic factors as well as metabolic pathways that take advantage of 'omics' technologies could play a very relevant part in combating obesity within a precision approach.