Cross-regulation of C/EBP alpha and PPAR gamma controls the transcriptional pathway of adipogenesis and insulin sensitivity

19q13.11 microdeletion: Clinical features overlapping ectrodactyly ectodermal dysplasia-clefting syndrome phenotype

We report a patient who was followed for a long time under an ectrodactyly ectodermal dysplasia-clefting (EEC) syndrome and was subsequently diagnosed with a 19q13.11 microdeletion. After a review of the related literature, we suggest testing patients with EEC for 19q13.11 microdeletion and include WTIP and UBA2 to a minimal overlapping region.

Concerted redox modulation by sulforaphane alleviates diabetes and cardiometabolic syndrome

Diabetes and cardiometabolic disorders such as hypertension and obesity are major risk factors for the development of cardiovascular disease, with a wealth of evidence suggesting that oxidative stress is linked to the initiation and pathogenesis of these disease processes. With yearly increases in the global incidence of cardiovascular diseases (CVD) and diabetes, numerous studies have focused on characterizing whether upregulating antioxidant defenses through exogenous antioxidants (e.g. vitamin E, vitamin C) or activation of endogenous defenses (e.g. the Nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant defense pathway) may be of benefit. The dietary isothiocyanate sulforaphane (SFN) is currently the subject of several clinical trials for a variety of disease states, including the evaluation of its therapeutic potential to ameliorate diabetic and cardiometabolic complications. SFN is a well characterized and potent Nrf2 inducer, however recent studies suggest its protective actions may be in part mediated by its modulation of various pro-inflammatory (e.g. Nuclear factor-kappa B (NFκB)) and metabolic (e.g. Peroxisome Proliferator-Activator Receptor Gamma (PPARγ)) signaling pathways. The focus of this review is to provide a detailed analysis of the known mechanisms by which SFN modulates Nrf2, NFκB and PPARγ signaling and crosstalk and to provide a critical evaluation of the evidence linking these transcriptional pathways with diabetic and cardiometabolic complications and SFN mediated cytoprotection. To allow comparison between rodent and human studies, we discuss the published bioavailability of SFN metabolites achieved in rodents and man in the context of Nrf2, NFκB and PPARγ signaling. Furthermore, we provide an update on the functional outcomes and implicated signaling pathways reported in recent clinical trials with SFN in Type 2 diabetic patients.

HMGB2 is a novel adipogenic factor that regulates ectopic fat infiltration in skeletal muscles

Although various surgical procedures have been developed for chronic rotator cuff tear repair, the re-tear rate remains high with severe fat infiltration. However, little is known about the molecular regulation of this process. Mesenchymal stem cells (MSCs) in the intra-muscular space are origin of ectopic fat cells in skeletal muscle. We have previously shown that high-mobility group box 2 (HMGB2), which is a nuclear protein commonly associated with mesenchymal differentiation, is involved in the early articular cartilage degeneration. In this study, we addressed the role of HMGB2 in adipogenesis of MSCs and fat infiltration into skeletal muscles. HMGB2 was highly expressed in undifferentiated MSCs and co-localized with platelet-derived growth factor receptor α (PDGFRA) known as an MSC-specific marker, while their expressions were decreased during adipocytic differentiation. Under the deficiency of HMGB2, the expressions of adipogenesis-related molecules were reduced, and adipogenic differentiation is substantially impaired in MSCs. Moreover, HMGB2⁺ cells were generated in the muscle belly of rat supraspinatus muscles after rotator cuff transection, and some of these cells expressed PDGFRA in intra-muscular spaces. Thus, our findings suggest that the enhance expression of HMGB2 induces the adipogenesis of MSCs and the fat infiltration into skeletal muscles through the cascade of HMGB2-PDGFRA.

Pathological Implication of Adipocytes in AAA Development and the Rupture

Abdominal aortic aneurysm (AAA) is a vascular disease that involves the gradual dilation of the abdominal aorta followed by its rupture. AAA is closely associated with weakening of the vascular wall due to oxidative stress, chronic inflammation, and degradation of the extracellular matrix. No effective drug therapy is currently available for preventing aneurysm progression or rupture. Adipocytes in the vascular wall are reportedly closely associated with AAA development and rupture. Fiber degradation in the aneurysm wall is enhanced by increased numbers of adipocytes, and rupture risk may increase as well. Recent studies suggested that appropriate control of adipocytes in the vascular wall may be an important strategy to prevent AAA rupture, and further studies may aid in the establishment of a method for preventing AAA rupture by therapeutic drugs or functional foods. In this review, we summarize adipocyte function and the correlation between AAA and adipocytes.

Anti-obesity Effect of Halophyte Crop, Limonium tetragonum in High-Fat Diet-Induced Obese Mice and 3T3-L1 Adipocytes

Halophyte Limonium tetragonum has recently been of interest in Korea for its nutritional value and salty taste which made it an ideal vegetable. In this study, the potential of L. tetragonum preventing excess weight gain, obesity and the related health problem has been evaluated in vitro and in vivo. The treatment with 100 mg/kg of L. tetragonum EtOAc soluble fraction (EALT) apparently prevented the body weight gain, adipose tissue weight gain, and the increase of triglyceride and total cholesterol level in mice fed a high-fat diet for 8 weeks. In addition, both glucose tolerance and insulin resistance in dietary obese mice were improved by EALT administration. A marked decrease in adipocyte differentiation was observed in the EALT (50 µg/mL)-treated 3T3-L1 cells, which was mediated by the suppression of adipogenesis-related transcription factors including peroxisome proliferator-activated receptor (PPAR) γ, CCAAT/enhancer binding protein (C/EBP)α, and Sterol regulatory element binding protein-1 (SREBP-1) and adipocyte-specific proteins such as fatty acid synthase (FAS), lipoprotein lipase (LPL), and adipocyte fatty acid-binding protein (aP2). The major components contained in EALT were identified as (-)-epigallocatechin-3-(3″-O-methyl) gallate, (-)-epigallocatechin-3-gallate, and myricetin-3-O-β-D-galactopyranoside based on its phytochemical analysis. Results suggested that EALT might be available as functional crop and bioactive diet supplement for the prevention and/or treatment of obesity.

Complex toxicity as disruption of adipocyte or osteoblast differentiation in human mesenchymal stem cells under the mixed condition of TBBPA and TCDD

People are frequently and unintentionally exposed to many chemical compounds, such as environmental pollutants and endocrine-disrupting chemicals (EDCs), in food and from the atmosphere. In particular, endocrine-disrupting TBBPA and dioxins are found in human breast milk and in the body. Conventional studies evaluate toxicity by administering a single substance to cells or animals, but evaluation of the toxicity of mixtures of these ingested compounds is essential for “true” toxicological assessment. We evaluated toxic effects in vitro using human mesenchymal stem cells (hMSCs). TBBPA increased the number of lipid droplets, and upregulated the expression of adipocyte-related mRNA, aP2 and LPL, through a PPARγ-dependent mechanism. TCDD suppressed lipid droplets and adipocyte-related mRNA levels. Adipocyte differentiation was stimulated by TBBPA and inhibited by TCDD in a dose-dependent manner. TBBPA did not influence osteoblast differentiation, but TCDD suppressed ALP staining and activity, calcium deposition, and osteoblast-related mRNA levels. In a mixture of TBBPA and TCDD, TBBPA inhibited TCDD suppression of adipocyte and osteoblast differentiation in a dose-dependent manner. Interestingly, we observed lipid droplets in TBBPA-treated cells differentiated into osteoblasts. These results suggest that TBBPA and TCDD disrupted differentiation into adipocytes and osteoblasts and contributes to a more complete toxicological understanding of exposure to these chemical substances.

Lanthionine synthetase C-like protein 2 (LanCL2) is important for adipogenic differentiation

Adipogenic differentiation is a highly regulated process that is necessary for metabolic homeostasis and nutrient sensing. The expression of PPARγ and the subsequent activation of adipogenic genes is critical for the process. In this study, we identified lanthionine synthetase C-like protein 2 (LanCL2) as a positive regulator of adipogenesis in 3T3-L1 cells. Knockdown of LanCL2, but not LanCL1, inhibited adipogenic differentiation, and this effect was not mediated through cAMP or Akt signaling pathways. The expression of early adipogenic markers CCAAT enhancer binding protein β (C/EBPβ) and C/EBPδ remained intact in LanCL2 knockdown cells, but levels of late adipogenic markers PPARγ and C/EBPα were suppressed. The addition of the naturally occurring PPARγ activator 15-deoxy-Δ^12,14-prostaglandin J2 or conditioned medium from differentiating cells did not restore differentiation, implying that LanCL2 may not be involved in the production of a secreted endogenous PPARγ ligand. Pulldown assays demonstrated a direct physical interaction between LanCL2 and PPARγ. Consistent with a regulatory role of LanCL2, luciferase reporter assays revealed that full transcriptional activation by PPARγ was dependent on LanCL2. Taken together, our study reveals a novel role of LanCL2 in adipogenesis, specifically involved in PPARγ-mediated transactivation of downstream adipogenic genes.

Eupatilin inhibits adipogenesis through suppression of PPARγ activity in 3T3-L1 cells

Eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone) is a flavonoid compound from Artemisia species that possesses beneficial biological activities such as anti-cancer, anti-oxidation, and anti-inflammatory activities. However, an anti-adipogenic effect has not yet been reported. In this study, we found that eupatilin significantly inhibited the adipogenesis of 3T3-L1 adipocytes. Eupatilin decreased intracellular lipid accumulation and suppressed the expression level of key adipogenic regulators in 3T3-L1 adipocytes, including peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT-enhancer-binding protein alpha (C/EBPα), in a concentration-dependent manner. These results show that eupatilin significantly inhibits 3T3-L1 cell differentiation and suggest that it has potential as a novel anti-obesity therapy.

Glehnia littoralis Root Extract Inhibits Fat Accumulation in 3T3-L1 Cells and High-Fat Diet-Induced Obese Mice by Downregulating Adipogenic Gene Expression

Glehnia littoralis has been reported to have several pharmacological properties but no reports describing the antiadipogenic effect of this plant have been published. This study was conducted to investigate the effects of Glehnia littoralis root hot water extract (GLE) and its underlying mechanism on 3T3-L1 cell adipogenesis and in high-fat diet- (HFD-) induced obese mice. We measured intracellular lipid accumulation using oil red O staining in vitro. For in vivo study, twenty-eight C57BL/6J male mice were randomly divided into four groups, Control, HFD, HFD + 1% GLE, and HFD + 5% GLE, which was performed for eight weeks. We determined the expression levels of the adipogenesis-related proteins by RT-PCR and western blotting in HFD-induced obese mice. The GLE dose-dependently inhibited 3T3-L1 adipocyte differentiation and intracellular lipid accumulation in differentiated adipocytes. Further, body weight gain and fat accumulation were significantly lower in the GLE-treated HFD mice than in the untreated HFD mice. GLE treatment suppressed the expression of adipogenic genes such as peroxisome proliferator-activated receptor (PPAR) γ, CCAAT/enhancer-binding protein (C/EBP) α, fatty acid synthase (aP2), and fatty acid synthase (FAS). These results suggest that the GLE inhibits adipocyte differentiation and intracellular lipid accumulation by downregulating the adipogenic gene expression both in vitro and in vivo.

Lysophosphatidylcholine acyltransferase 3 deficiency impairs 3T3L1 cell adipogenesis through activating Wnt/β-catenin pathway

Levels of polyunsaturated phosphatidylcholine (PC) influence plasma membrane structure and function. Phosphatidylcholine (PC) is synthesized de novo in the Kennedy pathway and then undergoes extensive deacylation/reacylation remodeling via Lands' cycle (non-Kennedy pathway). The reacylation is catalyzed by lysophosphatidylcholine acyltransferase (LPCAT), which adds a polyunsaturated fatty acid at the sn-2 position. Four LPCAT isoforms have been described to date, among which we found LPCAT3 to be the major isoform in adipose tissue, but its exact role in adipogenesis is unclear. In this study, we aimed to investigate whether LPCAT3 activity affects 3T3L1 cell adipogenic differentiation potential and its underline mechanism. Lentivirus-mediated LPCAT3 shRNA expression stably knocked down LPCAT3 in 3T3L1 preadipocytes and LPCAT3 deficiency dramatically reduced the levels of cellular polyunsaturated PCs. Importantly, we found that this deficiency activated the β-catenin dependent Wnt signaling pathway, which suppressed the expression of adipogenesis-related genes, thereby inhibiting 3T3L1 preadipocyte differentiation and lipid accumulation. Moreover, three different Wnt/β-catenin pathway inhibitors reversed the effect of LPCAP3 deficiency, suggesting that Wnt/β-catenin pathway activation is one of the causes for the observed phenotypes. To the best of our knowledge, we show here for the first time that PC remodeling is an important regulator of adipocyte differentiation.

Targeting sphingosine-1-phosphate lyase as an anabolic therapy for bone loss

Sphingosine-1-phosphate (S1P) signaling influences bone metabolism, but its therapeutic potential in bone disorders has remained unexplored. We show that raising S1P levels in adult mice through conditionally deleting or pharmacologically inhibiting S1P lyase, the sole enzyme responsible for irreversibly degrading S1P, markedly increased bone formation, mass and strength and substantially decreased white adipose tissue. S1P signaling through S1P₂ potently stimulated osteoblastogenesis at the expense of adipogenesis by inversely regulating osterix and PPAR-γ, and it simultaneously inhibited osteoclastogenesis by inducing osteoprotegerin through newly discovered p38-GSK3β-β-catenin and WNT5A-LRP5 pathways. Accordingly, S1P₂-deficient mice were osteopenic and obese. In ovariectomy-induced osteopenia, S1P lyase inhibition was as effective as intermittent parathyroid hormone (iPTH) treatment in increasing bone mass and was superior to iPTH in enhancing bone strength. Furthermore, lyase inhibition in mice successfully corrected severe genetic osteoporosis caused by osteoprotegerin deficiency. Human data from 4,091 participants of the SHIP-Trend population-based study revealed a positive association between serum levels of S1P and bone formation markers, but not resorption markers. Furthermore, serum S1P levels were positively associated with serum calcium , negatively with PTH , and curvilinearly with body mass index. Bone stiffness, as determined through quantitative ultrasound, was inversely related to levels of both S1P and the bone formation marker PINP, suggesting that S1P stimulates osteoanabolic activity to counteract decreasing bone quality. S1P-based drugs should be considered as a promising therapeutic avenue for the treatment of osteoporotic diseases.

Bergamottin Inhibits Adipogenesis in 3T3-L1 Cells and Weight Regulation in Diet-Induced Obese Mice

Obesity is a serious and increasing health problem worldwide, and the inhibition of adipogenesis is considered to be a potential therapeutic target for it. Bergamottin (BGM), a component of grapefruit juice, has been reported to regulate lipolysis. However, the physiological role of BGM in obesity has not been evaluated so far. In the present study, we investigated the effects of BGM on obesity in 3T3-L1 cells and in mice fed a high-fat diet (HFD). BGM inhibited adipogenic differentiation of 3T3-L1 cells along with a significant decrease in the lipid content by downregulating the expression of two critical adipogenic factors, CCAAT enhancer-binding protein-alpha (C/EBP[Formula: see text]) and peroxisome proliferator activated receptor-gamma (PPAR[Formula: see text]). The expressions of target proteins such as adipocyte fatty acid-binding protein (aP2), adiponectin, and resistin were also decreased by BGM. It activated AMP-activated protein kinase (AMPK) by increasing phosphorylation of AMPK and the downstream target acetyl-CoA carboxylase (ACC), indicating that BGM exerted its antiadipogenic effect through AMPK activation. In the HFD-induced obese mouse model, BGM administration significantly reduced the weight and sizes of white adipose tissue as well as the weight gain of mice fed HFD. Moreover, UCP1 and PGC1[Formula: see text] expressions, well-known as brown adipocyte marker genes, were higher in the BGM-treated HFD mice than that in the HFD-induced obese mice. This study suggests that BGM suppress adipogenesis by AMPK activation in vitro and reduces body weight in vivo.

The Differentiation Balance of Bone Marrow Mesenchymal Stem Cells Is Crucial to Hematopoiesis

Bone marrow mesenchymal stem cells (BMSCs), the important component and regulator of bone marrow microenvironment, give rise to hematopoietic-supporting stromal cells and form hematopoietic niches for hematopoietic stem cells (HSCs). However, how BMSC differentiation affects hematopoiesis is poorly understood. In this review, we focus on the role of BMSC differentiation in hematopoiesis. We discussed the role of BMSCs and their progeny in hematopoiesis. We also examine the mechanisms that cause differentiation bias of BMSCs in stress conditions including aging, irradiation, and chemotherapy. Moreover, the differentiation balance of BMSCs is crucial to hematopoiesis. We highlight the negative effects of differentiation bias of BMSCs on hematopoietic recovery after bone marrow transplantation. Keeping the differentiation balance of BMSCs is critical for hematopoietic recovery. This review summarises current understanding about how BMSC differentiation affects hematopoiesis and its potential application in improving hematopoietic recovery after bone marrow transplantation.

Short-term disuse promotes fatty acid infiltration into skeletal muscle

BACKGROUND

Many physiological and/or pathological conditions lead to muscle deconditioning, a well-described phenomenon characterized by a loss of strength and muscle power mainly due to the loss of muscle mass. Fatty infiltrations, or intermuscular adipose tissue (IMAT), are currently well-recognized components of muscle deconditioning. Despite the fact that IMAT is present in healthy human skeletal muscle, its increase and accumulation are linked to muscle dysfunction. Although IMAT development has been largely attributable to inactivity, the precise mechanisms of its establishment are still poorly understood. Because the sedentary lifestyle that accompanies age-related sarcopenia may favour IMAT development, deciphering the early processes of muscle disuse is of great importance before implementing strategies to limit IMAT deposition.

METHODS

In our study, we took advantage of the dry immersion (DI) model of severe muscle inactivity to induce rapid muscle deconditioning during a short period. During the DI, healthy adult men (n = 12; age: 32 ± 5) remained strictly immersed, in a supine position, in a controlled thermo-neutral water bath. Skeletal muscle biopsies were obtained from the vastus lateralis before and after 3 days of DI.

RESULTS

We showed that DI for only 3 days was able to decrease myofiber cross-sectional areas (-10.6%). Moreover, protein expression levels of two key markers commonly used to assess IMAT, perilipin, and fatty acid binding protein 4, were upregulated. We also observed an increase in the C/EBPα and PPARγ protein expression levels, indicating an increase in late adipogenic processes leading to IMAT development. While many stem cells in the muscle environment can adopt the capacity to differentiate into adipocytes, fibro-adipogenic progenitors (FAPs) represent the population that appears to play a major role in IMAT development. In our study, we showed an increase in the protein expression of PDGFRα, the specific cell surface marker of FAPs, in response to 3 days of DI. It is well recognized that an unfavourable muscle environment drives FAPs to ectopic adiposity and/or fibrosis.

CONCLUSIONS

This study is the first to emphasize that during a short period of severe inactivity, muscle deconditioning is associated with IMAT development. Our study also reveals that FAPs could be the main resident muscle stem cell population implicated in ectopic adiposity development in human skeletal muscle.

Toosendanin inhibits adipogenesis by activating Wnt/β-catenin signaling

Toosendanin (TSN), a triterpenoid extracted from Melia toosendan, has been reported to possess anti-oxidant, anti-inflammatory, anti-allergic, and anti-arthritic activities. However, its anti-adipogenic effect remains unknown. Here, we found that TSN dose-dependently attenuated lipid accumulation in preadipocytes 3T3-L1 as evidenced by Oil Red O staining. TSN also significantly downregulated mRNA and protein levels of adipocytokines (adiponectin and leptin), CCAAT/enhancer binding proteins α (C/EBP-α), peroxisome proliferator-activated receptor γ (PPAR-γ), fatty acid synthase, and acetyl-CoA carboxylase in adipocytes. To understand the mechanism, we observed that TSN effectively activated Wnt/β-catenin pathway, in which TSN increased low density lipoprotein receptor related protein 6, disheveled 2, β-catenin, and cyclin D1 expression levels, while it inactivated glycogen synthase kinase 3β by enhancing its phosphorylation. Moreover, TSN reduced weight of gonadal white fat and serum triacylglycerol (TAG) content in high-fat diet (HFD)-fed mice. Interestingly, the in vivo studies also demonstrated that TSN promoted the expression of β-catenin, but accordingly repressed C/EBP-α and PPAR-γ expression in HFD-induced mice. Overall, TSN is capable of inhibiting the lipogenesis of adipocytes by activating the Wnt/β-catenin pathway, suggesting potential application of TSN as a natural anti-obesity agent.

The effects of exercise training associated with low-level laser therapy on biomarkers of adipose tissue transdifferentiation in obese women

Investigations suggest the benefits of low-level laser therapy (LLLT) to improve noninvasive body contouring treatments, inflammation, insulin resistance and to reduce body fat. However, the mechanism for such potential effects in association with exercise training (ET) and possible implications in browning adiposity processes remains unclear. Forty-nine obese women were involved, aged between 20 and 40 years with a body mass index (BMI) of 30-40 kg/m². The volunteers were divided into Phototherapy (808 nm) and SHAM groups. Interventions consisted of exercise training and phototherapy applications post exercise for 4 months, with three sessions/week. Body composition, lipid profile, insulin resistance, atrial natriuretic peptide (ANP), WNT5 signaling, interleukin-6 (IL-6), and fibroblast growth factor-21 (FGF-21) were measured. Improvements in body mass, BMI, body fat mass, lean mass, visceral fat, waist circumference, insulin, HOMA-IR, total cholesterol, LDL-cholesterol, triglycerides, and ANP in both groups were demonstrated. Only the Phototherapy group showed a reduction in interleukin-6 and an increase in WNT5 signaling. In addition, it was possible to observe a higher magnitude change for the fat mass, insulin, HOMA-IR, and FGF-21 variables in the Phototherapy group. In the present investigation, it was demonstrated that exercise training associated with LLLT promotes an improvement in body composition and inflammatory processes as previously demonstrated. The Phototherapy group especially presented positive modifications of WNT5 signaling, FGF-21, and ANP, possible biomarkers associated with browning adiposity processes. This suggests that this kind of intervention promotes results applicable in clinical practice to control obesity and related comorbidities.

Euglena extract suppresses adipocyte-differentiation in human adipose-derived stem cells

Euglena gracilis Z (Euglena) is a unicellular, photosynthesizing, microscopic green alga. It contains several nutrients such as vitamins, minerals, and unsaturated fatty acids. In this study, to verify the potential role of Euglena consumption on human health and obesity, we evaluated the effect of Euglena on human adipose-derived stem cells. We prepared a Euglena extract and evaluated its effect on cell growth and lipid accumulation, and found that cell growth was promoted by the addition of the Euglena extract. Interestingly, intracellular lipid accumulation was inhibited in a concentration-dependent manner. Quantitative real-time PCR analysis and western blotting analysis indicated that the Euglena extract suppressed adipocyte differentiation by inhibiting the gene expression of the master regulators peroxisome proliferator-activated receptor-γ (PPARγ) and one of three CCAAT-enhancer-binding proteins (C/EBPα). Further Oil Red O staining experiments indicated that the Euglena extract inhibited the early stage of adipocyte-differentiation. Consistent with these results, we observed that down-regulation of gene expression was involved in the early stage of adipogenesis represented by the sterol regulatory element binding protein 1 c (SREBP1c), two of three CCAAT-enhancer-binding proteins (C/EBPβ, C/EBPδ), and the cAMP regulatory element-binding protein (CREB). Taken together, these data suggest that Euglena extract is a promising candidate for the development of a new therapeutic treatment for obesity.

Chrysanthemum indicum Inhibits Adipogenesis and Activates the AMPK Pathway in High-Fat-Diet-Induced Obese Mice

Chrysanthemum indicum (CI) is widely distributed in China and many parts of the tropical world, and has been reported to have antibacterial, antiviral, anti-oxidant and immunomodulatory effects, but no information is available on its effects on high fat diet (HFD)-induced obesity. This was undertaken to investigate the mechanism responsible for the effect of ethyl acetate fraction of CI (CIEA) on adipogenesis, in vitro and in vivo models of obesity. In the in vitro study, differentiating 3T3-L1 cells were treated with media to initiate differentiation (MDI) in the presence or absence of CIEA with different concentrations, and in the in vivo study, C57BL/6 mice were fed with HFD and administered CIEA daily for six weeks. Garcinia cambogia (GC) was used as the positive control, and was administered in the same manner as CIEA. Results showed CIEA reduced HFD-induced body weight gain, epididymal white adipose tissue (eWAT), and liver weight. In addition, CIEA significantly decreased serum lipid profiles, including total cholesterol (TC), triglyceride (TG) and low density lipoprotein cholesterol (LDLc) and increased high density lipoprotein cholesterol (HDLc) levels. Furthermore, CIEA also reduced leptin levels and increased adiponectin levels in serum, and significantly decreased peroxisome proliferator-activated receptor [Formula: see text] (PPAR[Formula: see text]) and CCAAT/enhancer-binding protein (C/EPBs) levels, but increased PPAR[Formula: see text] level and the phosphorylation of AMP-activated protein kinase (AMPK) in eWATs and in the liver tissues of HFD fed obese mice. Taken together, these results indicate CIEA might be beneficial for preventing obesity.

Molecular mechanisms of the anti-obesity effect of bioactive compounds in tea and coffee

Obesity is a serious health problem in adults and children worldwide. However, the basic strategies for the management of obesity (diet, exercise, drugs and surgery) have limitations and side effects. Therefore, many researchers have sought to identify bioactive components in food. Tea and coffee are the most frequently consumed beverages in the whole world. Their health benefits have been studied for decades, especially those of green tea. The anti-obesity effect of tea and coffee has been studied for at least ten years. The results have shown decreased lipid accumulation in cells via the regulation of the cell cycle during adipogenesis, changes in transcription factors and lipogenesis-related proteins in the adipose tissue of animal models, and decreased body weight and visceral fat in humans. Tea and coffee also influence the gut microbiota in obese animals and humans. Although the anti-obesity mechanism of tea and coffee still needs further clarification, they may have potential as a new strategy to prevent or treat obesity.

Betaine Supplementation Enhances Lipid Metabolism and Improves Insulin Resistance in Mice Fed a High-Fat Diet

Obesity is a major driver of metabolic diseases such as nonalcoholic fatty liver disease, certain cancers, and insulin resistance. However, there are no effective drugs to treat obesity. Betaine is a nontoxic, chemically stable and naturally occurring molecule. This study shows that dietary betaine supplementation significantly inhibits the white fat production in a high-fat diet (HFD)-induced obese mice. This might be due to betaine preventing the formation of new white fat (WAT), and guiding the original WAT to burn through stimulated mitochondrial biogenesis and promoting browning of WAT. Furthermore, dietary betaine supplementation decreases intramyocellular lipid accumulation in HFD-induced obese mice. Further analysis shows that betaine supplementation reduced intramyocellular lipid accumulation might be associated with increasing polyunsaturated fatty acids (PUFA), fatty acid oxidation, and the inhibition of fatty acid synthesis in muscle. Notably, by performing insulin-tolerance tests (ITTs) and glucose-tolerance tests (GTTs), dietary betaine supplementation could be observed for improvement of obesity and non-obesity induced insulin resistance. Together, these findings could suggest that inhibiting WAT production, intramyocellular lipid accumulation and inflammation, betaine supplementation limits HFD-induced obesity and improves insulin resistance.

Coumestrol modulates Akt and Wnt/β-catenin signaling during the attenuation of adipogenesis

Coumestrol is a natural phytochemical present in plants such as red clover and soy, and has been reported to stimulate the estrogen receptor as a major phytoestrogen. While the molecular mechanisms responsible for the anti-adipogenic effects of phytoestrogens such as genistein and daidzein have been previously investigated, the effects of coumestrol on adipogenesis remain to be elucidated. We observed that coumestrol dose-dependently attenuates MDI (mixture of 3-isobutyl-1-methylxanthine, dexamethasone, and insulin)-induced lipid accumulation, consistent with an earlier study, while significantly inhibiting MDI-induced adipogenesis in the first 48 hours of differentiation, a critical time window for anti-adipogenic effects. Coumestrol treatment suppressed MDI-induced protein expression of PPARγ and C/EBPα in adipocytes, leading to the subsequent downregulation of FAS and aP2 expression. Akt and GSK3β were phosphorylated shortly after MDI stimulation, and these responses were inhibited by coumestrol treatment. Coumestrol also increased LRP6 protein expression, resulting in the recovery of β-catenin downregulation by MDI, while attenuating MDI-induced downregulation of Wnt10b. In addition, mRNA and protein expression of c-Myc and cyclin D1, target genes of β-catenin, were both recovered by coumestrol treatment. These results suggest that coumestrol inhibits adipocyte differentiation via regulation of Akt and Wnt/β-catenin signaling and may have potential for development as an agent to prevent adipogenesis.

Effects of protein and fat concentration in coproduct-based growing calf diets on adipogenic and lipogenic gene expression, blood metabolites, and carcass composition

Crossbred calves ( = 30; age = 95 ± 1.7 d; BW = 179 ± 18 kg) were fed 1 of 5 growing diets: 1) corn-based control, 2) low-fat, low-protein coproduct blend, 3) high-fat, low-protein coproduct blend, 4) low-fat, high-protein coproduct blend, and 5) high-fat, high-protein coproduct blend for 112 d (growing phase) followed by a common corn-based finishing diet (additional 112 d; finishing phase). Calves were biopsied at 0, 112, and 224 d for transcriptional analysis via real-time quantitative PCR of 14 genes associated with adipogenesis and lipogenesis within the muscle. Serum was collected at d 0, 112, and 224 and analyzed for leptin, IGF-1, and GH concentration. Treatments were arranged in a 2 × 2 factorial. Data were analyzed using the MIXED procedures of SAS (SAS Inst. Inc., Cary, NC) to ascertain the effects of 2 protein levels, 2 fat levels, time, and any interactions. Increased protein and decreased fat in the growing diet resulted in a carryover effect that increased ( 0.01) gene expression of PPARγ, insulin-induced gene 1, thyroid hormone responsive SPOT14 protein, ATP citrate lyase, adiponectin, diacylglycerol O-acyltransferase homologue 2, fatty acid binding protein 4, fatty acid synthase, phosphoenolpyruvate carboxykinase 1, and stearoyl-CoA desaturase as well as serum leptin concentrations between d 112 and 224. Expression of sterol regulatory element binding transcription factor 1 was increased ( 0.01) at d 112 in steers fed high-protein, high-fat diets compared to those fed high-protein, low-fat diets. A fat × day interaction ( 0.01) occurred for the expression of adiponectin receptor 2 and CCAAT/enhancer binding protein alpha, resulting in a carryover effect wherein low-fat diets fed during the growing phase increased expression of both genes at the end of the finishing phase (d 224). After slaughter, cattle fed the control during the growing phase tended ( 0.09) to have greater marbling scores, whereas other carcass parameters were not different ( ≥ 0.13). These data indicate that feeding differing levels of dietary fat and protein during the growing phase does affect i.m. adipogenesis at the transcriptional level, but differences in gene expression were not sufficient to affect carcass quality among cattle fed coproducts.

Mechanistic Insights Into the Interaction Between Transcription Factors and Epigenetic Modifications and the Contribution to the Development of Obesity

Objective: The development of obesity is inseparable from genetic and epigenetic factors, and transcription factors (TFs) play an essential role in these two mechanisms. This review analyzes the interaction of TFs with epigenetic modifications and the epigenetic mechanisms underlying peroxisome proliferator-activated receptor (PPAR)γ, an important transcription factor, in the development of obesity. Methods: We describe the relationship between TFs and different epigenetic modifications and illustrate the several mechanisms described. Next, we summarize the epigenetic mechanisms of PPARs, an important class of transcription factors involved in obesity, that induce obesity with different triggering factors. Finally, we discuss the mechanisms of epigenetic modification of PPAR-related ligands in lipid metabolism and propose future avenues of research. Results: TFs participate in epigenetic modifications in different forms, causing changes in gene expression. The interactions between the different epigenetic modifications and PPARs are important biological developments that affect fat tissue differentiation, lipogenesis, and lipid metabolism, thereby inducing or inhibiting the development of obesity. We then highlight the need for more research to understand the role of epigenetic modifications and PPARs. Conclusions: Epigenetic mechanisms involved in the regulation of PPARs may be excellent therapeutic targets for obesity treatment. However, there is a need for a deeper understanding of how PPARs and other obesity-related transcription factors interact with epigenetic modifications.

Molecular Mechanisms Responsible for Anti-inflammatory and Immunosuppressive Effects of Mesenchymal Stem Cell-Derived Factors

Mesenchymal stem cells (MSCs) are self-renewable cells capable for multilineage differentiation and immunomodulation. MSCs are able to differentiate into all cell types of mesodermal origin and, due to their plasticity, may generate cells of neuroectodermal or endodermal origin in vitro. In addition to the enormous differentiation potential, MSCs efficiently modulate innate and adaptive immune response and, accordingly, were used in large number of experimental and clinical trials as new therapeutic agents in regenerative medicine. Although MSC-based therapy was efficient in the treatment of many inflammatory and degenerative diseases, unwanted differentiation of engrafted MSCs represents important safety concern. MSC-based beneficial effects are mostly relied on the effects of MSC-derived immunomodulatory, pro-angiogenic, and trophic factors which attenuate detrimental immune response and inflammation, reduce ischemic injuries, and promote tissue repair and regeneration. Accordingly, MSC-conditioned medium (MSC-CM), which contains MSC-derived factors, has the potential to serve as a cell-free, safe therapeutic agent for the treatment of inflammatory diseases. Herein, we summarized current knowledge regarding identification, isolation, ontogeny, and functional characteristics of MSCs and described molecular mechanisms responsible for MSC-CM-mediated anti-inflammatory and immunosuppressive effects in the therapy of inflammatory lung, liver, and kidney diseases and ischemic brain injury.

Expression regulation and functional analysis of RGS2 and RGS4 in adipogenic and osteogenic differentiation of human mesenchymal stem cells

BACKGROUND

Understanding the molecular basis underlying the formation of bone-forming osteocytes and lipid-storing adipocytes will help provide insights into the cause of disorders originating in stem/progenitor cells and develop therapeutic treatments for bone- or adipose-related diseases. In this study, the role of RGS2 and RGS4, two members of the regulators of G protein signaling (RGS) family, was investigated during adipogenenic and osteogenenic differentiation of human mesenchymal stem cells (hMSCs).

RESULTS

Expression of RGS2 and RGS4 were found to be inversely regulated during adipogenesis induced by dexamethasone (DEX) and 3-isobutyl-methylxanthine, regardless if insulin was present, with RGS2 up-regulated and RGS4 down-regulated in response to adipogenic induction. RGS2 expression was also up-regulated during osteogenesis at a level similar to that induced by treatment of DEX alone, a shared component of adipogenic and osteogenic differentiation inducing media, but significantly lower than the level induced by adipogenic inducing media. RGS4 expression was down-regulated during the first 48 h of osteogenesis but up-regulated afterwards, in both cases at levels similar to that induced by DEX alone. Expression knock-down using small interfering RNA against RGS2 resulted in decreased differentiation efficiency during both adipogenesis and osteogenesis. On the other hand, expression knock-down of RGS4 also resulted in decreased adipogenic differentiation but increased osteogenic differentiation.

CONCLUSIONS

RGS2 and RGS4 are differentially regulated during adipogenic and osteogenic differentiation of hMSCs. In addition, both RGS2 and RGS4 play positive roles during adipogenesis but opposing roles during osteogenesis, with RGS2 as a positive regulator and RGS4 as a negative regulator. These results imply that members of RGS proteins may play multifaceted roles during human adipogenesis and osteogenesis to balance or counterbalance each other's function during those processes.

Evaluating antidisease immunity to malaria and implications for vaccine design

Immunity to malaria could be categorized broadly as antiparasite or antidisease immunity. While most vaccine research efforts have focused on antiparasite immunity, the evidence from endemic populations suggest that antidisease immunity is an important component of natural immunity to malaria. The processes that mediate antidisease immunity have, however, attracted little to no attention, and most interests have been directed towards the antibody responses. This review evaluates the evidence for antidisease immunity in endemic areas and discusses the possible mechanisms responsible for it. Given the key role that inflammation plays in the pathogenesis of malaria, regulation of the inflammatory response appears to be a major mechanism for antidisease immunity in naturally exposed individuals.

Anti-adipogenic effects of the traditional herbal formula Dohongsamul-tang in 3T3-L1 adipocytes

Background

Blood stasis syndrome (BSS) is a general pattern identification and refers to pathological stagnation of blood circulation, dysfunction of endothelial cells or metabolic disorder in traditional Korean medicine (TKM). Dohongsamul-Tang (DHSMT) is a well-known traditional herbal formula which used for treatment and prevention of BSS by promoting blood circulation in TKM.

Methods

Cytotoxicity of DHSMT was examined by cell counting kit-8 (CCK-8). We also investigated the anti-adipogenesis effect of DHSMT by using Oil Red O staining, intracellular triglyceride assay leptin ELISA and western blot analysis in 3T3-L1 adipocytes. In addition, the accumulation of adiponectin, resistin and plasminogen activator inhibitor-1 (PAI-1) were measured by magnetic bead panel kit.

Results

Oil Red O staining showed that DHSMT markedly reduced fat accumulation without affecting cell cytotoxicity. DHSMT also significantly decreased accumulation of triglyceride and adipokines such as leptin, adiponectin, resistin and PAI-1 compared with fully differentiated adipocytes. Furthermore, our results found that DHSMT significantly suppressed the adipocyte differentiation by downregulating adipogenic-specific transcriptional factors such as peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer binding proteins alpha (C/EBPα) and fatty acid binding protein 4 (FABP4) in adipocytes.

Conclusions

Taken together, our findings provide that DHSMT has potential for treatment and prevention of obesity or MS related to BSS.

Anti-obesity molecular mechanism of soy isoflavones: weaving the way to new therapeutic routes

Obesity is ringing alarm bells globally. Advances in food science and nutrition research have been devoted to identifying food components that exert anti-obesity effects, as well as investigating the molecular mechanisms by which they modulate the progression of obesity. Soy foods have attracted much interest as high-protein components of the human diet and as unique sources of isoflavones. As they have similar chemical structures to endogenous estrogens, isoflavones are believed to interact with intracellular estrogen receptors, which results in reductions in the accumulation of lipids and the distribution of adipose tissue. Both in vitro and in vivo studies have revealed other signaling pathways in which isoflavones are involved in the inhibition of adipogenesis and lipogenesis by interacting with various transcription factors and upstream signaling molecules. Although the biological mechanisms that cause the biphasic effects of isoflavones and various controversial results remain unknown, it is noteworthy that isoflavones exhibit pleiotropic effects in the human body to regulate metabolism and balance, which may potentially prevent and treat obesity.

Low-level perfluorooctanoic acid enhances 3 T3-L1 preadipocyte differentiation via altering peroxisome proliferator activated receptor gamma expression and its promoter DNA methylation

Recent studies suggest that perfluorooctanoic acid (PFOA) can play a role in the development of obesity; however, the associated mechanisms are poorly understood. We investigated how PFOA exposure affected the differentiation of 3 T3-L1 preadipocytes and the associated transcriptional and epigenetic mechanisms. Cells treated with different doses of PFOA (ranging from 0.01 to 100 μg ml^-1 ) were assessed for proliferation, differentiation and triglyceride accumulation. The gene expression levels of peroxisome proliferator activated receptor gamma (PPARγ) and its target genes were measured. DNA methylation levels of PPARγ promoter and global DNA methylation levels were also tested. We found a concentration-dependent enhancement of adipocyte proliferation and differentiation following PFOA exposure. PFOA also induced a significant concentration-dependent increase in the accumulation of lipid and triglyceride. Increased gene expression was also observed for PPARγ, CCAAT/enhancer binding proteins α, fatty acid binding protein 2 and lipoprotein lipase in differentiated cells after PFOA exposure. The ability of PFOA to induce adipogenesis was blocked by GW9662, a known PPARγ antagonist. In addition, significant demethylation of the cytosine-phosphate-guanine sites in the PPARγ promoter was observed after exposure to PFOA. In addition, PFOA exposure resulted in decreased global DNA methylation and increased expression levels of DNA methyltransferases genes. We found that treatment with low levels of PFOA can induce adipogenic differentiation in preadipocytes, and the underlying mechanisms probably involve the activation of PPARγ transcription and demethylation of PPARγ promoter.

Dihydrosanguinarine Enhances Glucose Uptake in Mouse 3T3-L1 Cells

Recently, more studies have aimed at identifying selective peroxisome proliferator-activated receptor gamma (PPARγ) modulators that transactivate the expression of PPARγ-dependent genes as partial agonists to improve diabetic symptoms with fewer side effects compared to classic PPARγ agonists such as thiazolidinediones. We found that dihydrosanguinarine (DHS) treatment induced preadipocyte differentiation and lipid droplet accumulation in 3T3-L1 cells, but this effect is weaker than that elicited by the full PPARγ agonist troglitazone. Furthermore, this effect was reduced by the addition of a PPARγ antagonist, indicating the involvement of PPARγ signaling. Our results suggest that the stimulatory effects of DHS on adipocyte differentiation and insulin sensitivity are mediated by suppressing adenosine monophosphate-activated protein kinase (AMPK) alpha, upregulating the expression of PPARγ and its target genes (particularly Glut-4 and adiponectin) and reducing PPARγ phosphorylation. DHS significantly enhanced the glucose uptake in 3T3-L1 adipocytes without observable cytotoxicity at the effective concentration (5 μM) applied.

The Role of Cellular Proliferation in Adipogenic Differentiation of Human Adipose Tissue-Derived Mesenchymal Stem Cells

Mitotic clonal expansion has been suggested as a prerequisite for adipogenesis in murine preadipocytes, but the precise role of cell proliferation during human adipogenesis is unclear. Using adipose tissue-derived human mesenchymal stem cells as an in vitro cell model for adipogenic study, a group of cell cycle regulators, including Cdk1 and CCND1, were found to be downregulated as early as 24 h after adipogenic initiation and consistently, cell proliferation activity was restricted to the first 48 h of adipogenic induction. Cell proliferation was either further inhibited using siRNAs targeting cell cycle genes or enhanced by supplementing exogenous growth factor, basic fibroblast growth factor (bFGF), at specific time intervals during adipogenesis. Expression knockdown of Cdk1 at the initiation of adipogenic induction resulted in significantly increased adipocytes, even though total number of cells was significantly reduced compared to siControl-treated cells. bFGF stimulated proliferation throughout adipogenic differentiation, but exerted differential effect on adipogenic outcome at different phases, promoting adipogenesis during mitotic phase (first 48 h), but significantly inhibiting adipogenesis during adipogenic commitment phase (days 3-6). Our results demonstrate that cellular proliferation is counteractive to adipogenic commitment in human adipogenesis. However, cellular proliferation stimulation can be beneficial for adipogenesis during the mitotic phase by increasing the population of cells capable of committing to adipocytes before adipogenic commitment.

Mesenchymal stem cells in obesity: insights for translational applications

Obesity is now a major public health problem worldwide. Lifestyle modification to reduce the characteristic excess body adiposity is important in the treatment of obesity, but effective therapeutic intervention is still needed to control what has become an obesity epidemic. Unfortunately, many anti-obesity drugs have been withdrawn from market due to adverse side effects. Bariatric surgery therefore remains the most effective therapy for severe cases, although such surgery is invasive and researchers continue to seek new control strategies for obesity. Mesenchymal stem cells (MSCs) are a major source of adipocyte generation, and studies have been conducted into the potential roles of MSCs in treating obesity. However, despite significant progress in stem cell research and its potential applications for obesity, adipogenesis is a highly complex process and the molecular mechanisms governing MSC adipogenesis remain ill defined. In particular, successful clinical application of MSCs will require extensive identification and characterization of the transcriptional regulators controlling MSC adipogenesis. Since obesity is associated with the incidence of multiple important comorbidities, an in-depth understanding of the relationship between MSC adipogenesis and the comorbidities of obesity is also necessary to evaluate the potential of effective and safe MSC-based therapies for obesity. In addition, brown adipogenesis is an attractive topic from the viewpoint of therapeutic innovation and future research into MSC-based brown adipogenesis could lead to a novel breakthrough. Ongoing stem cell studies and emerging research fields such as epigenetics are expected to elucidate the complicated mechanisms at play in MSC adipogenesis and develop novel MSC-based therapeutic options for obesity. This review discusses the current understanding of MSCs in adipogenesis and their potential clinical applications for obesity.

Adiponectin receptor agonist AdipoRon suppresses adipogenesis in C3H10T1/2 cells through the adenosine monophosphate‑activated protein kinase signaling pathway

The aim of the present study was to investigate the effects of AdipoRon, an adiponectin receptor agonist, on adipogenesis in C3H10T1/2 cells and to explore the underlying mechanisms. C3H10T1/2 cells were treated with increasing doses of AdipoRon for 8 days, and Oil Red O staining was used to assess lipid accumulation. The protein and mRNA expression levels of adipogenic transcription factors and adipocyte‑specific genes were examined by western blotting and reverse transcription quantitative polymerase chain reaction, respectively. AdipoRon treatment inhibited lipid accumulation in C3H10T1/2 cells in a dose‑dependent manner and significantly suppressed the expression of adipogenic transcription factors, including peroxisome proliferator‑activated receptor γ, CAAT/enhancer binding protein (C/EBP)‑β and C/EBPα. In addition, cells treated with AdipoRon exhibited a significant decrease in the expression of adipocyte‑specific genes, including fatty acid binding protein 4, fatty acid synthase, leptin, adiponectin, and stearoyl‑CoA desaturase‑1. Notably, AdipoRon significantly increased the phosphorylation of adenosine monophosphate‑activated protein kinase (AMPK) and acetyl‑CoA carboxylase (ACC). The results indicated that AdipoRon exerted an inhibitory effect on adipogenesis in C3H10T1/2 cells by downregulating the expression of adipogenic transcription factors and adipocyte‑specific genes and by promoting the phosphorylation of AMPK and ACC, which suggested that AdipoRon may be a potential drug to prevent and treat diseases caused by abnormal adipogenesis, such as obesity.

In vitro structure-specific Zn(II)-induced adipogenesis and structure-function bioreactivity correlations

The advent of Zn(II) metallodrugs in metabolic syndrome pathologies generates a strong challenge toward synthetic endeavors targeting well-defined, atoxic and biologically active binary/ternary species of Zn(II). Proper formulation of that metal ion's coordination sphere sets the stage for construction of appropriately configured Schiff ligands based on tromethamine and variably modified vanillin core components. The arising Schiff ligands react with Zn(II) in a defined stoichiometry, thereby delivering new binary Zn(II)-L species with defined physicochemical properties. Analytical (elemental), spectroscopic (FT-IR, Thermogravimetric Analysis) and crystallographic techniques attest to the distinct nature of the derived binary-ternary materials, bearing defined Zn(II):L molecular stoichiometry, variable nuclearity, charge, bulk and balance mix of hydrophilicity-hydrophobicity, thereby providing the physicochemical profile based on which biological studies could ensue. The structurally based selection of species was applied onto in vitro 3T3-L1 cultures, essentially exploring toxicity, migration, morphology, cell differentiation and maturation. The systematic effort toward comparative work on appropriately defined Zn(II) species and insulin in inducing adipogenesis reveals the salient structural features in the Schiff family of ligands configuring Zn(II) so as to promote complex formation sufficient to engage biomolecular targets during the process of initiation and maturation. Molecular targets of importance in adipogenesis were examined under the influence of Zn(II) and their expression levels suggest the structural composition that a Zn(II) ion might have to optimally pursue cell differentiation. Thus, a well-defined selection of binary Zn(II)-L species is tightly associated with the incurred bioactivity, thereby setting the stage for the development of efficient Zn(II) metallodrugs to combat Diabetes mellitus II.

Neural EGF-like protein 1 (NELL-1): Signaling crosstalk in mesenchymal stem cells and applications in regenerative medicine

Bone tissue regeneration holds the potential to solve both osteoporosis and large skeletal defects, two problems associated with significant morbidity. The differentiation of mesenchymal stem cells into the osteogenic lineage requires a specific microenvironment and certain osteogenic growth factors. Neural EGF Like-Like molecule 1 (NELL-1) is a secreted glycoprotein that has proven, both in vitro and in vivo, to be a potent osteo-inductive factor. Furthermore, it has been shown to repress adipogenic differentiation and inflammation. NELL-1 can work synergistically with other osteogenic factors such as Bone Morphogenic Protein (BMP) -2 and -9, and has shown promise for use in tissue engineering and as a systemically administered drug for the treatment of osteoporosis. Here we provide a comprehensive up-to-date review on the molecular signaling cascade of NELL-1 in mesenchymal stem cells and potential applications in bone regenerative engineering.

Physiological regulation and metabolic role of browning in white adipose tissue

Great progress has been made in our understanding of the browning process in white adipose tissue (WAT) in rodents. The recognition that i) adult humans have physiologically inducible brown adipose tissue (BAT) that may facilitate resistance to obesity and ii) that adult human BAT molecularly and functionally resembles beige adipose tissue in rodents, reignited optimism that obesity and obesity-related diabetes type 2 can be battled by controlling the browning of WAT. In this review the main cellular mechanisms and molecular mediators of browning of WAT in different physiological states are summarized. The relevance of browning of WAT in metabolic health is considered primarily through a modulation of biological role of fat tissue in overall metabolic homeostasis.

Extracellular calcium modulates brown adipocyte differentiation and identity

Brown adipocytes are important in regulating non-shivering thermogenesis, whole body glucose and lipid homeostasis. Increasing evidence supports an important role of metabolites as well as macro- and micronutrients in brown adipocyte differentiation and function. Calcium is one of the most abundant ions in the body regulating multiple cellular processes. We observed that increasing extracellular calcium concentration during brown adipocyte differentiation blocks lipid accumulation and suppresses induction of major adipogenic transcription factors such as PPARγ and C/EBPα. In contrast, the depletion of calcium in the medium enhances adipogenesis and expression of brown adipocyte selective genes, such as UCP1. Mechanistically, we show that elevated extracellular calcium inhibits C/EBPβ activity through hyperactivation of ERK, a process that is independent of intracellular calcium levels and reversibly halts differentiation. Moreover, increased extracellular calcium solely after the induction phase of differentiation specifically suppresses gene expression of UCP1, PRDM16 and PGC1-α. Notably, depleting extracellular calcium provokes opposite effects. Together, we show that modulating extracellular calcium concentration controls brown adipocyte differentiation and thermogenic gene expression, highlighting the importance of tissue microenvironment on brown adipocyte heterogeneity and function.

Induced Pluripotent Stem Cell Differentiation Enables Functional Validation of GWAS Variants in Metabolic Disease

Genome-wide association studies (GWAS) have highlighted a large number of genetic variants with potential disease association, but functional analysis remains a challenge. Here we describe an approach to functionally validate identified variants through differentiation of induced pluripotent stem cells (iPSCs) to study cellular pathophysiology. We collected peripheral blood cells from Framingham Heart Study participants and reprogrammed them to iPSCs. We then differentiated 68 iPSC lines into hepatocytes and adipocytes to investigate the effect of the 1p13 rs12740374 variant on cardiometabolic disease phenotypes via transcriptomics and metabolomic signatures. We observed a clear association between rs12740374 and lipid accumulation and gene expression in differentiated hepatocytes, in particular, expression of SORT1, CELSR2, and PSRC1, consistent with previous analyses of this variant using other approaches. Initial investigation of additional SNPs also highlighted correlations with gene expression. These findings suggest that iPSC-based population studies hold promise as tools for the functional validation of GWAS variants.

Conjugated Linoleic Acid Supplementation Improves Maternal High Fat Diet-Induced Programming of Metabolic Dysfunction in Adult Male Rat Offspring

The developmental origins of health and disease hypothesis proposes that an adverse early life environment, including in utero exposure to a maternal obesogenic environment, can lead to an increased long-term risk of obesity and related metabolic complications in offspring. We assessed whether maternal supplementation with conjugated linoleic acid (CLA) could prevent some of these adverse effects in offspring exposed to a maternal high fat diet. Sprague-Dawley dams consumed either a: control (CD), control with CLA (CLA), high fat (HF) or high fat with CLA (HFCLA) diet 10 days prior to mating and throughout pregnancy/lactation. Male offspring were weaned onto a standard chow diet. Body composition was quantified by DXA and oral glucose tolerance tests conducted on adult offspring. Gene/protein expression and histological analysis were conducted in adipose tissue. Offspring from HF dams had increased body weight, body fat deposition, impaired insulin sensitivity and adipocyte hypertrophy; all of which were rescued in HFCLA offspring. Molecular and histological analyses of the adipose tissue suggest that disturbances in adipogenesis may mediate the metabolic dysfunction observed in HF offspring. Therefore, CLA supplementation to a maternal obesogenic diet may be a promising strategy to prevent adverse programming outcomes.

Adiposity and adipogenic gene expression in four different muscles in beef cattle

Anatomical site and divergent functionalities of muscles can be related to differences in IMF content, metabolism and adipogenic gene expression. Then, potential differences in different muscles in beef cattle were studied. As a second objective, the main sources of experimental variability associated to RT-qPCR results were analyzed following a nested design in order to implement appropriate experimental designs minimizing gene expression variability. To perform the study Longissimus thoracis (LT), Semitendinosus (SM), Masseter (MS), Sternomandibularis (ST) and subcutaneous adipose tissue (SAT) samples of Pirenaica young bulls (n = 4) were collected for IMF, collagen and protein quantification, analysis of adipocyte size distribution and gene expression (PPARG, CEBPA, FAPB4 and WNT10B). A greater IMF content was observed in MS and SM muscles, which had a bimodal adipocyte size distribution while it was unimodal in the muscles LT and ST. This suggest that the different IMF accretion in the muscles studied might be related to different rates of hyperplasia and hypertrophy and that IMF might develop later in LT and ST muscles. The former differences were not mirrored by the expression of the genes analyzed, which might be related to the different contribution of mature and non-mature adipocytes to the total gene expression. When comparing IMF and SAT gene expression, late and early developing tissues respectively, expression of PPARG, CEBPA and FABP4 was higher in the SAT, in agreement with bigger cell size and numbers. The variability study indicates that the analytical factors that add higher variability to the gene expression are the sampling and RT and therefore, it would be appropriate to include those replicates in the design of future experiments. Based on the results, the use of MS and SM muscles could allow less expensive experimental designs and bigger sample size that could permit the detection of lower relevant differences in gene expression.

B-cell identity as a metabolic barrier against malignant transformation

B-lineage and myeloid leukemia cells are often transformed by the same oncogenes, but have different biological and clinical characteristics. Although B-lineage acute lymphoblastic leukemia (B-ALL) cells are characterized by a state of chronic energy deficit, myeloid leukemia cells show abundant energy reserve. Interestingly, fasting has been demonstrated to inhibit selectively the development of B-ALL but not myeloid leukemia, further suggesting that lineage identity may be linked to divergent metabolic states in hematopoietic malignancies. The B-lymphoid transcription factors IKZF1, EBF1, and PAX5 are essential for early B-cell development and commitment to B-cell identity. However, in >80% of human pre-B-ALL cases, the leukemic clones harbor genetic lesions of these transcription factors. The significance of these defects has only recently been investigated. Here, we discuss the unexpected function of a B-lymphoid transcriptional program as a metabolic barrier against malignant transformation of B-cell precursor cells. The metabolic gatekeeper function of B-lymphoid transcription factors may force silent preleukemic clones carrying potentially oncogenic lesions to remain in a latent state. In addition, this program sets the threshold for responses to glucocorticoids in pre-B-ALL. Finally, the link between the tumor-suppressor and metabolic functions of B-lymphoid transcription factors is matched by observations in clinical trials: obesity and hyperglycemia are associated with poor clinical outcome in patients with pre-B-ALL.