Inhibitory effect of sinigrin on adipocyte differentiation in 3T3-L1 cells: Involvement of AMPK and MAPK pathways

Anti-Obesity and Anti-Diabetic Effects of Ostericum koreanum (Ganghwal) Extract

"Ganghwal" is a widely used herbal medicine in Republic of Korea, but it has not been reported as a treatment strategy for obesity and diabetes within adipocytes. In this study, we determined that Ostericum koreanum extract (OKE) exerts an anti-obesity effect by inhibiting adipogenesis and an anti-diabetic effect by increasing the expression of genes related to glucose uptake in adipocytes and inhibiting α-glucosidase activity. 3T3-L1 preadipocytes were differentiated for 8 days in methylisobutylxanthine, dexamethasone, and insulin medium, and the effect of OKE was confirmed by the addition of 50 and 100 µg/mL of OKE during the differentiation process. This resulted in a reduction in lipid accumulation and the expression of PPARγ (Peroxisome proliferator-activated receptor γ) and C/EBPα (CCAAT enhancer binding protein α). Significant activation of AMPK (AMP-activated protein kinase), increased expression of GLUT4 (Glucose Transporter Type 4), and inhibition of α-glucosidase activity were also observed. These findings provide the basis for the anti-obesity and anti-diabetic effects of OKE. In addition, OKE has a significant antioxidant effect. This study presents OKE as a potential natural product-derived material for the treatment of patients with metabolic diseases such as obesity- and obesity-induced diabetes.

Screening and identification of lncRNAs in preadipocyte differentiation in sheep

Studies of preadipocyte differentiation and fat deposition in sheep have mainly focused on functional genes, and with no emphasis placed on the role that long non-coding RNAs (lncRNAs) may have on the activity of those genes. Here, the expression profile of lncRNAs in ovine preadipocyte differentiation was investigated and the differentially expressed lncRNAs were screened on day 0 (D0), day 2(D2) and day 8(D8) of ovine preadipocyte differentiation, with their target genes being predicted. The competing endogenous RNA (ceRNA) regulatory network was constructed by GO and KEGG enrichment analysis for functional annotation, and some differentially expressed lncRNAs were randomly selected to verify the RNA-Seq results by RT-qPCR. In the study, a total of 2517 novel lncRNAs and 3943 known lncRNAs were identified from ovine preadipocytes at the three stages of differentiation, with the highest proportion being intergenic lncRNAs. A total of 3455 lncRNAs were expressed at all three stages of preadipocyte differentiation, while 214, 226 and 228 lncRNAs were uniquely expressed at day 0, day 2 and day 8, respectively. By comparing the expression of the lncRNAs between the three stages of differentiation stages, a total of 405, 272 and 359 differentially expressed lncRNAs were found in D0-vs-D2, D0-vs-D8, and D2-vs-D8, respectively. Functional analysis revealed that the differentially expressed lncRNAs were enriched in signaling pathways related to ovine preadipocyte differentiation, such as mitogen-activated protein kinase (MAPK) pathway, the phosphoinositide 3-kinase protein kinase B (PI3K-Akt) pathway, and the transforming growth factor beta (TGF-β) pathway. In summary, lncRNAs from preadipocytes at different stages of differentiation in sheep were identified and screened using RNA-Seq technology, and the regulatory mechanisms of lncRNAs in preadipocyte differentiation and lipid deposition were explored. This study provides a theoretical reference for revealing the roles of lncRNAs in ovine preadipocyte differentiation and also offers a theoretical basis for further understanding the regulatory mechanisms of ovine preadipocyte differentiation.

Sesamin and sesamolin potentially inhibit adipogenesis through downregulating the peroxisome proliferator-activated receptor γ protein expression and activity in 3T3-L1 cells

Sesamin and sesamolin are major sesame lignans that have demonstrated anti-inflammatory, anticancer, and neuroprotective properties and potential benefits in the liver, cardiovascular diseases, and metabolic syndrome. However, despite previous research on their antiobesity effects and underlying mechanisms, a comprehensive investigation of these aspects is still lacking. In this study, we evaluated the regulatory effects of 20 to 80 µM sesamin and sesamolin on adipogenesis in vitro using 3T3-L1 cells as a model cell line. We hypothesized that the lignans would inhibit adipogenic differentiation in 3T3-L1 cells through the regulation of peroxisome proliferator-activated receptor γ (PPARγ). Our data indicate that sesamin and sesamolin inhibited the adipogenic differentiation of 3T3-L1 cells by dose-dependently decreasing lipid accumulation and triglyceride formation. Sesamin and sesamolin reduced the mRNA and protein expression of the adipogenesis-related transcription factors, PPARγ and CCAAT/enhancer-binding protein α, leading to the dose-dependent downregulations of their downstream targets, fatty acid binding protein 4, hormone-sensitive lipase, lipoprotein lipase, and glucose transporter 4. In addition, glucose uptake was dose-dependently attenuated by sesamin and sesamolin in both differentiated 3T3-L1 cells and HepG2 cells. Interestingly, our results suggested that sesamin and sesamolin might directly bind to PPARγ to inhibit its transcriptional activity. Finally, sesamin and sesamolin decreased the phosphorylation of 3 mitogen-activated protein kinase signaling components in differentiated 3T3-L1 cells. Taken together, our findings suggest that sesamin and sesamolin may exhibit antiobesity effects by potentially downregulating PPARγ and its downstream genes through the mitogen-activated protein kinase signaling pathway, offering important insights into the molecular mechanisms underlying the potential antiobesity effects of sesamin and sesamolin.

Sinigrin improves cerebral ischaemia-reperfusion injury by inhibiting the TLR4 pathway-mediated oxidative stress

Cerebral ischaemia-reperfusion (CIR) injury occurs in stroke patients after the restoration of cerebral perfusion. Sinigrin, a phytochemical found in cruciferous vegetables, exhibits strong antioxidant activity. This study investigated the role of sinigrin in oxidative stress using a CIR injury model. The effects of sinigrin were studied in middle cerebral artery occlusion (MCAO) rats and oxygen-glucose deprivation/reoxygenation (OGD/R)-injured SH-SY5Y cells. Sinigrin treatment improved brain injury and neurological deficits induced by MCAO surgery in rats. Sinigrin inhibited apoptosis in brain tissues and SH-SY5Y cells following OGD/R induction. Additionally, sinigrin elevated the levels of superoxide dismutase (SOD), glutathione (GSH) and glutathione peroxidase (GSH-Px) while reducing malondialdehyde (MDA) levels. Furthermore, sinigrin inhibited the toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88) signalling pathway. The anti-apoptotic and antioxidant activities of sinigrin in OGD/R-injured SH-SY5Y cells were reversed by TLR4 overexpression. In conclusion, sinigrin inhibits oxidative stress in CIR injury by suppressing the TLR4/MyD88 signalling pathway.

Anti-adipogenic action of a novel oxazole derivative through activation of AMPK pathway

Obesity is a chronic disorder with multifactorial etiology, including genetic, medical, dietary and other environmental factors. Both natural and synthetic heterocyclic compounds, especially oxazoles, represent an interesting group of compounds and have gained much attention due to their remarkable biological activities. Therefore, a library of 3,3-DMAH (3,3-dimethylallylhalfordinol) inspired N-alkylated oxazole bromide salts with varied substitutions were prepared and screened using the 3T3-L1 model of adipogenesis and HFD-induced obesity model in Syrian golden hamsters. Several compounds in the synthesized series displayed remarkable anti-adipogenic potential on the differentiation of 3T3-L1 preadipocytes. Compound 19e, displayed the most potent activity of all and selected for further studies. Compound 19e inhibited mitotic clonal expansion of 3T3-L1 cells and enhanced the mitochondrial oxygen consumption rate of the cells during early phase of differentiation via AMPK activation. 19e also improved the dyslipidaemia in high calorie diet fed Syrian Golden Hamsters. Therefore, compound 19e can serve as a potential lead against adipogenesis and dyslipidaemia models and could be further investigated to affirm its significance as a drug candidate.

M1 linear ubiquitination of LKB1 inhibits vascular endothelial cell injury in atherosclerosis through activation of AMPK

Endothelial cell injury is confirmed to be the initial step in the atherosclerosis (AS) process. Here, we tried to elucidate the role of liver kinase B1 (LKB1) and adenosine phosphate protein kinase (AMPK) in modulating vascular endothelial cells (VECs) in AS. High-fat feed (HFD)-induced AS rat models were prepared and treated with AMPK activator A-769662 alone or combined with chloroquine. An analysis of VEC injury, inflammation response, and autophagy followed it. The M1 linear ubiquitination of LKB1 was assessed by co-immunoprecipitation. The interaction between LKB1 and AMPK was analyzed. Primary aortic VECs were isolated and induced by LPS to verify the effects of LKB1 and AMPK on VEC injury in AS. Activation of AMPK reduced the VEC injury and inflammatory response of VECs and promoted autophagy caused by AS. LKB1 could regulate the activation of AMPK in AS. M1 linear ubiquitination enhanced LKB1 activity and increased AMPK activation to protect against VEC injury in AS, which was validated by in vitro experiments. Our current study highlighted that M1 linear ubiquitination of LKB1 may induce the activation of LKB1 to activate AMPK, which inhibited VEC injury in AS.

Krill oil inhibited adipogenic differentiation by inducing the nuclear Nrf2 expression and the AMPK activity

The current study investigated the antiadipogenic mechanism of krill oil from the 3T3-L1 adipocytes. The krill oil adhered to the criteria as a food standard by showing 50.8% of the total phospholipid, 5.27% myristic acid, and 1.63% linoleic acid. The lipid accumulation that was measured in the 3T3-L1 cells using oil red O staining was reduced up to 54% by the krill oil. The krill oil treatment reduced the adipogenic transcription factors by downregulating the sterol regulatory element binding protein 1 (SREBP1) and acetyl-CoA carboxylase (ACC), phospho-ACC, and AMP-activated protein kinase (AMPK) phosphorylation. The current study confirmed that the krill oil inhibited adipogenesis by downregulating SREBP1 and ACC via the upregulation of the AMPK and nuclear factors E2-related factor 2 (Nrf2) signaling pathway in the 3T3-L1 adipocytes. These findings suggest that krill oil is a good source of phospholipid and phosphatidylcholine, which could be a potential natural antiobesity ingredient by inhibiting adipogenesis.

Molecular Mechanism of m6A Methylation Modification Genes METTL3 and FTO in Regulating Heat Stress in Sheep

Heat stress is an important environmental factor affecting livestock production worldwide. Primary hepatocytes and preadipocytes derived from Hu sheep were used to establish a heat stress model. Quantitative reverse transcriptase-PCR (qRT-PCR) analysis showed that heat induction significantly increased the expression levels of heat stress protein (HSP) genes and the N6-methyladenosine (m6A) methylation modification genes: methyltransferase-like protein 3 (METTL3), methyltransferase-like protein 14 (METTL14), and fat mass and obesity associated protein (FTO). Heat stress simultaneously promoted cell apoptosis. Transcriptome sequencing identified 3980 upregulated genes and 2420 downregulated genes related to heat stress. A pathway enrichment analysis of these genes revealed significant enrichment in fatty acid biosynthesis, degradation, and the PI3K-Akt and peroxisome proliferator-activated receptor (PPAR) signaling pathways. Overexpression of METTL3 in primary hepatocytes led to significant downregulation of HSP60, HSP70, and HSP110, and significantly increased mRNA m6A methylation; FTO interference generated the opposite results. Primary adipocytes showed similar results. Transcriptome analysis of cells under METTL3 (or FTO) inference and overexpression revealed differentially expressed genes enriched in the mitogen-activated protein kinase (MAPK) signaling pathways, as well as the PI3K-Akt and Ras signaling pathways. We speculate that METTL3 may increase the level of m6A methylation to inhibit fat deposition and/or inhibit the expression of HSP genes to enhance the body's resistance to heat stress, while the FTO gene generated the opposite molecular mechanism. This study provides a scientific basis and theoretical support for sheep feeding and management practices during heat stress.

The effects of short term blue light treatment on promoting nutrition value in Chinese cabbage

Chinese cabbage is a nutrients-rich vegetable with diverse leaf colors. Here, we used widely-targeted metabolomics technology to study the metabolic responses of three Chinese cabbage varieties with representative leaf colors after blue light treatment. The inner leaf color of orange varieties 20S530 and 15S1094 changed from yellow to golden yellow, while no visible color change occurred in the common variety 14S23 after the treatment. A total of 844 metabolites were measured from the leaf samples of these three varieties in a time course study after short term blue light treatment, with kaempferol-4'-O-glucoside, isoquercitrin, hyperin, arbutin, sulforaphane as enriched nutritional metabolites. Orange Chinese cabbage varieties showed additional nutrition enhancement after the treatment. This study is the first to explore the global metabolic responses of Chinese cabbage after blue light treatment, and our findings provided valuable insights on how to effectively use lighting conditions to enhance specific groups of nutrients in vegetables.

MiR-196b-3p and miR-450b-3p are key regulators of adipogenesis in porcine intramuscular and subcutaneous adipocytes

BACKGROUND

As components of white adipose tissue, porcine intramuscular (IM) and subcutaneous (SC) adipocytes undergo similar differentiation and adipogenesis processes. However, the adipogenic capacity of IM adipocytes is weaker than that of SC adipocytes. Identifying key regulators underlying this difference between IM and SC adipocytes will benefit pig breeding.

RESULTS

In this study, we used BGISEQ-500 sequencing technology to analyze the expression of small RNAs in primary cultured IM and SC adipocytes on day 8 after adipogenic induction, and found 32-fold higher miR-196b-3p expression, as well as 8-fold lower miR-450b-3p expression in IM adipocytes than in SC adipocytes. Functional studies revealed that miR-196b-3p inhibits adipogenesis by targeting CD47 via the AMPK signaling pathway, and its effect was attenuated by the specific p-AMPKα activator AICAR. We also found that miR-450b-3p promotes adipogenesis by targeting SIRT1 via the Wnt/β-catenin signaling pathway, and its effect was weakened by the Wnt/β-catenin signaling activator LiCl.

CONCLUSIONS

Our findings suggest that miR-196b-3p and miR-450b-3p are novel key regulatory factors that play opposite roles in porcine adipogenesis, helping us decipher the regulatory differences between porcine IM and SC fat deposition.

Production of Food-Derived Bioactive Peptides with Potential Application in the Management of Diabetes and Obesity: A Review

The prevalence of diabetes mellitus and obesity is increasing worldwide. Bioactive peptides are naturally present in foods or in food-derived proteins. Recent research has shown that these bioactive peptides have an array of possible health benefits in the management of diabetes and obesity. First, this review will summarize the top-down and bottom-up production methods of the bioactive peptides from different protein sources. Second, the digestibility, bioavailability, and metabolic fate of the bioactive peptides are discussed. Last, the present review will discuss and explore the mechanisms by which these bioactive peptides help against obesity and diabetes based on in vitro and in vivo studies. Although several clinical studies have demonstrated that bioactive peptides are beneficial in alleviating diabetes and obesity, more double-blind randomized controlled trials are needed in the future. This review has provided novel insights into the potential of food-derived bioactive peptides as functional foods or nutraceuticals to manage obesity and diabetes.

Differential gene expression analysis using RNA-seq in the blood of goats exposed to transportation stress

Transportation stress causes significant changes in physiological responses in goats; however, studies exploring the transcriptome of stress are very limited. The objective of this study was to determine the differential gene expressions and related pathways in the blood samples using RNA-seq procedure in Spanish goats subjected to different durations of transportation stress. Fifty-four male Spanish goats (8-mo old; BW = 29.7 ± 2.03 kg) were randomly subjected to one of three treatments (TRT; n = 18 goats/treatment): (1) transported for 180 min, (2) transported for 30 min, or (3) held in pens (control). Blood samples were collected before and after treatment for stress hormone, metabolite, and transcriptomic analysis. RNA-seq technology was used to obtain the transcriptome profiles of blood. Analysis of physiological data using SAS showed that plasma cortisol concentrations were higher (P < 0.01) in 180 min and 30 min groups compared to the control group. Enrichment analysis of DEGs related to transportation stress through Gene Ontology and KEGG databases revealed that the differentially expressed genes related to inflammatory pathways, caspases, and apoptosis such as IL1R2, CASP14, CD14, TLR4, and MAPK14 were highly enriched in the transported group of goats compared to non-transported goats. Stress in goats leads to a sequence of events at cellular and molecular levels that causes inflammation and apoptosis.

Euphylonoids A and B, Two Highly Modified Jatrophane Diterpenoids with Potent Lipid-Lowering Activity from Euphorbia hylonoma

Euphylonoids A (1) and B (2), two highly modified jatrophane diterpenoids, were isolated from Euphorbia hylonoma. 1 represents a new 9(10→18)-abeo-8,12-cyclojatrophane skeleton containing a cage-like 3,8-dioxatricyclo[5.1.2.0^4,9]decane core, while 2 is a 14(13→20)-abeo-8,12-cyclojatrophane featuring an unusual 17-oxatetracyclo[12.2.1.0^1,5.0^9,13]heptadecane framework. Their structural elucidation was completed by spectroscopic, chemical, computational, and single-crystal X-ray diffraction means. 2 significantly inhibited early adipogenesis in 3T3-L1 adipocytes via activating AMP-activated protein kinase signaling.

A Thai Traditional Triple-Fruit Formulation "Phikud Tri-Phon" May Provide Fat Loss and Nutritional Benefits

Obesity and overweight have serious health outcomes. “Phikud Tri-Phon” (PTP) is a traditional Thai medicine comprising three dried fruits from Aegle marmelos L., Morinda citrifolia L., and Coriandrum sativum L. Whether this medicine impacts on metabolic disease is unclear. This study aimed to investigate the phenolic and flavonoid contents of PTP and each of its herbal components, and further assess their antioxidant and anti-adipogenetic activities. Oil-red O staining was measured for lipid accumulation in 3T3-L1 adipocytes. The chemical profiles of PTP and each herbal extract were determined by LC-ESI-QTOF-MS/MS. Our results show that the total phenolic and flavonoid contents of PTP water extract were 22.35–108.42 mg of gallic acid equivalents and PTP ethanolic extract was 1.19–0.93 mg of quercetin equivalents and the DPPH scavenging capacity assay of PTP ethanolic extract (1 mg/mL) was 92.45 ± 6.58 (Trolox equivalent)/g. The PTP extracts and individual herbs had inhibitory adipogenesis activity, which reduced lipid accumulation by approximately 31% in PTP water extract and 22% in PTP ethanolic extract compared with control cells. These results provided insights into the traditional preparation method of using boiling water as a vehicle for PTP. In conclusion, PTP has antioxidant and anti-adipogenesis potential, indicating it is a promising ingredient in functional food and herbal health products.

Suppressive Effect of Fraxetin on Adipogenesis and Reactive Oxygen Species Production in 3T3-L1 Cells by Regulating MAPK Signaling Pathways

Recent studies have identified obesity as one of the world’s most serious chronic disorders. Adipogenesis, in which preadipocytes are differentiated into mature adipocytes, has a decisive role in establishing the number of adipocytes and determining the lipid storage capacity of adipose tissue and fat mass in adults. Fat accumulation in obesity is implicated with elevated oxidative stress in adipocytes induced by reactive oxygen species (ROS). Adipogenesis regulation by inhibiting adipogenic differentiation and ROS production has been selected as the strategy to treat obesity. The conventional anti-obesity drugs allowed by the U.S. Food and Drug Administration have severe adverse effects. Therefore, various natural products have been developed as a solution for obesity, suppressing adipogenic differentiation. Fraxetin is a major component extracted from the stem barks of Fraxinus rhynchophylla, with various bioactivities, including anti-inflammatory, anticancer, antioxidant, and antibacterial functions. However, the effect of fraxetin on adipogenesis is still not clearly understood. We studied the pharmacological functions of fraxetin in suppressing lipid accumulation and its underlying molecular mechanisms involving 3T3-L1 preadipocytes. Moreover, increased ROS production induced by a mixture of insulin, dexamethasone, and 3-isobutylmethylxanthine (MDI) in 3T3-L1 was attenuated by fraxetin during adipogenesis. These effects were regulated by mitogen-activated protein kinase (MAPK) signaling pathways. Therefore, our findings imply that fraxetin possesses inhibitory roles in adipogenesis and can be a potential anti-obesity drug.

Biosynthesis, distribution, nutritional and organoleptic properties of bitter compounds in fruit and vegetables

Compounds that confer a bitter taste on fruits and vegetables (FAVs) play crucial roles in both plant defense and health promotion. This review details the current knowledge of the distribution, properties (toxicity, pharmacological effects and receptors) and environmental plant responses relating to the biosynthesis, catabolism and transcriptional regulation of 53 bitter plant metabolites in diverse species of FAVs. Some bitter compounds, such as flavonoids, are common in all plant species and make a minor contribution to bitter flavor, but many are synthesized only in specific taxa. They make major contributions to the bitter taste of the corresponding species and some also have significant pharmacological effects. Levels of bitter metabolites are genetically determined, but various environmental cues can affect their final concentration during preharvest development and postharvest storage processes. Molecular approaches are helping to unravel the mechanisms of biosynthesis and regulation of bitter compounds in diverse crop species. This review not only discusses the theoretical basis for utilizing breeding programs and other agricultural technologies to produce FAVs with improved safety, favorable taste and healthier profiles, but also suggests new directions for the utilization of bitter compounds in FAVs for the development of natural pesticides and health-promoting medicines.

Immunostimulatory Activities of Theobromine on Macrophages via the Activation of MAPK and NF-κB Signaling Pathways

Theobromine is mainly found in plant foods, such as tea; the primary source of theobromine is the seeds of the Theobroma cacao tree. Theobromine is an alkaloid belonging to the methylxanthine class of drugs, and it is similar to theophylline and caffeine. Theobromine is known for its efficacy and role in health and disorder prevention. We evaluated the effects of theobromine on macrophage function, including the phosphorylation of mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB). Theobromine significantly stimulated the production of nitric oxide (NO) and prostaglandin E2 through immune responses, which relate to the increased expression of inducible nitric oxide synthase and cyclooxygenase-2. Additionally, theobromine increased the production of inflammatory cytokines, including tumor necrosis factor-α and interleukin-6 in macrophages. Additionally, theobromine induced the translocation and activity of NF-κB in a concentration-dependent manner. Consistent with these results, the phosphorylation level of MAPKs was increased in theobromine-stimulated macrophages. Collectively, these data revealed that theobromine acts as an immune response stimulator via the NF-κB and MAPKs signaling pathways. Thus, theobromine might have protective effects against inflammatory disorders.

Secondary Metabolites in the Dendrobium heterocarpum Methanolic Extract and Their Impacts on Viability and Lipid Storage of 3T3-L1 Pre-Adipocytes

Although many natural products have proven their potential to regulate obesity through the modulation of adipocyte biology, none of them has yet been approved for clinical use in obesity therapy. This work aims to isolate valuable secondary metabolites from an orchid species (Dendrobium heterocarpum) and evaluate their possible roles in the growth and differentiation of 3T3-L1 pre-adipocytes. Six compounds were isolated from the orchid’s methanolic extracts and identified as amoenylin (1), methyl 3-(4-hydroxyphenyl) propionate (2), 3,4-dihydroxy-5,4’-dimethoxybibenzyl (3), dendrocandin B (4), dendrofalconerol A (5), and syringaresinol (6). Among these phytochemicals, compounds 2, 3, and 6 exhibited lower effects on the viability of 3T3-L1 cells, offering non-cytotoxic concentrations of ≲ 10 µM. Compared to others tested, compound 3 was responsible for the maximum reduction of lipid storage in 3T3-L1 adipocytes (IC₅₀ = 6.30 ± 0.10 µM). A set of protein expression studies unveiled that compound 3 at non-cytotoxic doses could suppress the expression of some key transcription factors in adipocyte differentiation (i.e., PPARγ and C/EBPα). Furthermore, this compound could deactivate some proteins involved in the MAPK pathways (i.e., JNK, ERK, and p38). Our findings prove that D. heterocarpum is a promising source to explore bioactive molecules capable of modulating adipocytic growth and development, which can potentially be assessed and innovated further as pharmaceutical products to defeat obesity.

Nutraceutical potential of polyphenol-rich Sargassum species grown off the Korean coast: a review

Sargassum, a brown seaweed, has been used traditionally as food and medicine in Korea, China, and Japan. Sargassum spp. contain bioactive substances associated with health benefits, including anti-inflammatory and antioxidant effects. Thirty Sargassum spp. inhabit the Korean coast. However, their health benefits have yet to be systematically summarized. Therefore, the purpose of this article was to review the health benefits of these 30 Sargassum spp. grown off the Korean coast based on their health benefits, underlying mechanisms, and identified bioactive compounds.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01050-x.

Ameliorative Effects of Lactobacillus plantarum HAC01 Lysate on 3T3-L1 Adipocyte Differentiation via AMPK Activation and MAPK Inhibition

Lactobacillus plantarum HAC01 has been shown to effectively treat metabolic diseases. However, the precise pharmacological effects and molecular mechanisms of L. plantarum HAC01 remain unclear. In this study, we investigate the anti-adipogenic effects of L. plantarum HAC01 lysate and its associated mechanism of action. To induce lipid accumulation, 3T3-L1 cells were incubated in differentiation media with or without L. plantarum HAC01 lysate. Our results show that L. plantarum HAC01 lysate treatment not only reduced lipid accumulation during the differentiation of 3T3-L1 cells, but also decreased the expression of adipogenic and lipogenic genes involved in lipid metabolism in a dose-dependent manner. Additionally, L. plantarum HAC01 lysate inhibited CCAAT/enhancer-binding protein (C/EBP) beta within 4 h of differentiation induction and inhibited peroxisome proliferator-activated receptor gamma, C/EBP alpha, and sterol regulatory element-binding proteins within 2 d. Moreover, treatment with L. plantarum HAC01 lysate increased the phosphorylation of adenosine monophosphate-activated protein kinase, an important regulator of energy metabolism, and decreased the phosphorylation of mitogen-activated protein kinase. These results indicate that L. plantarum HAC01 lysate may have anti-adipogenic effects and support its potential as a useful agent for the treatment of obesity.

α-Glucosidase Inhibitory Activity and Anti-Adipogenic Effect of Compounds from Dendrobium delacourii

Chemical investigation of Dendrobium delacourii revealed 11 phenolic compounds, and the structures of these compounds were determined by analysis of their NMR and HR-ESI-MS data. All compounds were investigated for their α-glucosidase inhibitory activity and anti-adipogenic properties. Phoyunnanin E (10) and phoyunnanin C (11) showed the most potent α-glucosidase inhibition by comparing with acarbose, which was used as a positive control. Kinetic study revealed the non-competitive inhibitors against the enzyme. For anti-adipogenic activity, densifloral B (3) showed the strongest inhibition when compared with oxyresveratrol (positive control). In addition, densifloral B might be responsible for the inhibition of adipocyte differentiation via downregulating the expression of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT enhancer-binding protein alpha (C/EBPα), which are major transcription factors in adipogenesis.

Regulation of Methylase METTL3 on Fat Deposition

N6-methyladenosine (m6A) is the most prevalent and abundant type of internal post-transcriptional RNA modification in eukaryotic cells. METTL3 is a methylation modifying enzyme, which can directly or indirectly affect biological processes, such as RNA degradation, translation and splicing. In addition, it was found that 67% of 3'-UTR regions containing m6A sites had at least one miRNA binding site, and the number of m6A at 3'-UTR sites was closely related to the binding sites of miRNA. With the improvement of human living standards, obesity has become a very serious and urgent problem. The essence of obesity is the accumulation of excess fat. Exploring the origin and development mechanisms of adipocyte from the perspective of fat deposition has always been a hotspot in the field of adipocyte research. The aim of the present review is to focus on METTL3 regulating fat deposition through mRNA/adipocyte differentiation axis and pri-miRNA/pre-miRNA/target genes/adipocyte differentiation and to provide a theoretical basis according to the currently available literature for further exploring this association. This review may provide new insights for obesity, fat deposition disease and molecular breeding.

Adipose and non-adipose perspectives of plant derived natural compounds for mitigation of obesity

ETHNOPHARMACOLOGICAL RELEVANCE

Phyto-preparations and phyto-compounds, by their natural origin, easy availability, cost-effectiveness, and fruitful traditional uses based on accumulated experiences, have been extensively explored to mitigate the global burden of obesity.

AIM OF THIS REVIEW

The review aimed to analyse and critically summarize the prospect of future anti-obesity drug leads from the extant array of phytochemicals for mitigation of obesity, using adipose related targets (adipocyte formation, lipid metabolism, and thermogenesis) and non-adipose targets (hepatic lipid metabolism, appetite, satiety, and pancreatic lipase activity). Phytochemicals as inhibitors of adipocyte differentiation, modulators of lipid metabolism, and thermogenic activators of adipocytes are specifically discussed with their non-adipose anti-obesogenic targets.

MATERIALS AND METHODS

PubMed, Google Scholar, Scopus, and SciFinder were accessed to collect data on traditional medicinal plants, compounds derived from plants, their reported anti-obesity mechanisms, and therapeutic targets. The taxonomically accepted name of each plant in this review has been vetted from "The Plant List" (www.theplantlist.org) or MPNS (http://mpns.kew.org).

RESULTS

Available knowledge of a large number of phytochemicals, across a range of adipose and non-adipose targets, has been critically analysed and delineated by graphical and tabular depictions, towards mitigation of obesity. Neuro-endocrinal modulation in non-adipose targets brought into sharp dual focus, both non-adipose and adipose targets as the future of anti-obesity research. Numerous phytochemicals (Berberine, Xanthohumol, Ursolic acid, Guggulsterone, Tannic acid, etc.) have been found to be effectively reducing weight through lowered adipocyte formation, increased lipolysis, decreased lipogenesis, and enhanced thermogenesis. They have been affirmed as potential anti-obesity drugs of future because of their effectiveness yet having no threat to adipose or systemic insulin sensitivity.

CONCLUSION

Due to high molecular diversity and a greater ratio of benefit to risk, plant derived compounds hold high therapeutic potential to tackle obesity and associated risks. This review has been able to generate fresh perspectives on the anti-diabetic/anti-hyperglycemic/anti-obesity effect of phytochemicals. It has also brought into the focus that many phytochemicals demonstrating in vitro anti-obesogenic effects are yet to undergo in vivo investigation which could lead to potential phyto-molecules for dedicated anti-obesity action.

In-vitro Investigation of Polyphenol-Rich Date (Phoenix dactylifera L.) Seed Extract Bioactivity

Date seeds are a by-product of the date fruit processing industry with minimal human use; however, they are a rich source of polyphenols with a range of potential biological properties. The current study investigates the cytotoxicity of date seed polyphenols against cancer cell lines, its ability to combat hyperglycemia, its antioxidant potential and its anti-adipogenic effect. The present work aimed to establish the usefulness of date seeds in the food industry as a functional ingredient. The anti-tumour activity of DSE was tested in a panel of cell lines such as MCF-7, MDA-MB-231, Hep-G2, Caco-2, and PC-3 by measuring cell viability and cleaved PARP. Lipid accumulation and effect on the differentiation of 3T3-L1 cells (adipocytes) were tested with date seed extract treatments. The influence of date seed polyphenols on glucose uptake was studied in 3T3-L1 cells and C2C12 cells (muscle cells). The antioxidant activity of the polyphenols from date seed products such as date seed extract (DSE), date seed powder (DSP), and date seeds fortified bread (DSB) was tested following in-vitro digestion to study their stability in the gastrointestinal milieu. DSE treatment resulted in significantly reduced viability in MCF-7 and Hep-G2 cells with 48-h treatments. Glucose uptake increased in the adipocytes with DSE treatments; moreover, it inhibited adipocyte differentiation and lipid accumulation. DSE decreased the expression levels of PPAR-γ, C/EBPα, adiponectin and upregulated GLUT-4, and phospho-AMPK. This study also found that date seed samples retained antioxidant activity in the digestive milieu and concludes that the date seed polyphenols remain active in the digestive milieu and exhibit potential anti-hyperglycemic and anti-adipogenic activity.

Sinigrin attenuates angiotensin II‑induced kidney injury by inactivating nuclear factor‑κB and extracellular signal‑regulated kinase signaling in vivo and in vitro

The present study investigated the function of sinigrin in angiotensin II (Ang II)‑induced renal damage. The results demonstrated that systolic blood pressure (SBP) and diastolic blood pressure (DBP) were increased in Ang II‑challenged rats, and sinigrin treatment inhibited their increase. The levels of blood urea nitrogen (BUN) and serum creatinine (SCR) were increased by Ang II in the rats, and these were reversed by sinigrin in a dose‑dependent manner. In addition, the Ang II‑induced elevation of urinary protein levels was inhibited by sinigrin treatment. Glomerular basement membrane thickness and ECM degradation markers, such as collagen I, collagen IV and fibronectin, were suppressed by sinigrin in the Ang II‑challenged rats. Moreover, the levels of inflammatory regulators, including tumor necrosis factor‑α (TNF‑α), interleukin‑6 (IL‑6) and monocyte chemoattractant protein‑1 (MCP‑1), were reduced following sinigrin treatment of the Ang II‑challenged rats and in Ang II‑exposed proximal tubule epithelial cells. Furthermore, the superoxide dismutase (SOD) and catalase (CAT) levels were downregulated, whereas the malondialdehyde (MDA) levels were upregulated by Ang II; these effects were reversed by sinigrin treatment in vivo and in vitro. Mechanistically, sinigrin inhibited the Ang II‑induced phosphorylation of ERK, p65 and IκBα. Thus, sinigrin attenuated Ang II‑induced renal injury by inactivating ERK and NF‑κB signaling. Sinigrin may thus prove to be a potential candidate for the treatment of hypertension‑induced kidney damage.

Anti-Obesity and Lipid Lowering Activity of Bauhiniastatin-1 is Mediated Through PPAR-γ/AMPK Expressions in Diet-Induced Obese Rat Model

Objective: To evaluate the therapeutic efficacy and underlying molecular mechanisms of Bauhiniastatin-1 (BSTN1) to alleviate adiposity in diet-induced obese rodent model and in 3T3-L1 cells. Methods: BSTN1 was purified and confirmed through HPLC. In-vitro experiments such as MTT assay, Oil Red-O (ORO) stain, cellular lipid content, glycerol release and RT-PCR analysis were performed in 3T3-L1 cells in the presence and absence of BSTN1. In animal experiments, rats were divided into Group-I: normal pellet diet-fed, Group-II: HFD-fed, Groups-III, IV and V: HFD-fed BSTN1 (1.25, 2.5, and 5 mg/kg.b.wt./day/rat)-treated and Group-VI: HFD-fed Orlistat-treated. The rats were fed either normal diet or high fat diet (HFD) for 18 weeks and water ad-libitum. BSTN1 was orally administered from 13th week onwards to the selected HFD-fed groups. Body composition parameters, biochemical assays, histopathology examination and western blot analysis were performed to identify the predicted targets related to obesity. Molecular docking studies threw light on the binding interactions of BSTN1 against PPAR-γ, FAS and AMPK. Results: BSTN1 at 20 μM significantly (p < 0.001) inhibited adipocyte differentiation and lipid accumulation in 3T3-L1 cells. A conspicuous down-regulation in the mRNA expression levels of PPAR-γ, FAS and SREBP1 was observed but AMPK expression remained unchanged in BSTN1 treated 3T3-L1 cells. A substantial decrease in body weight gain, fat percent, total body fat, serum and liver lipid profile (except high-density lipoprotein), glucose, insulin and insulin resistance in BSTN1 treated rats was noticed in a dose dependent manner. In BSTN1 (5 mg/kg.b.wt.)-treated groups significantly (p < 0.01) elevated plasma adiponectin level but reduced leptin level as well as fall in serum AST and ALT were noticed. Further, the disturbed structural integrity and architecture of adipose and hepatic tissues due to high fat diet feeding were considerably recovered with BSTN1 treatment. Down-regulation in the protein expression level of PPAR-γ and activation of AMPK through phosphorylation was observed in BSTN1 treated rats than the untreated. Molecular docking studies revealed strong binding interactions of BSTN1 against PPAR-γ and AMPK and thus supported the experimental results. Conclusion: Taken together, the results suggest that BSTN1 could be a promising pharmacological molecule in the treatment of obesity and dyslipidemia.

Antiobesity effect of Brassica juncea cultivated in Jeongseon with optimized sinigrin content using 3T3-L1 adipocytes

In recent years, Brassica juncea has been selected as a special agricultural crop in Jeongseon, Gangwon-do, Korea, and is actively grown there. However, there have been no studies on B. juncea cultivated in Jeongseon (BJJ). Sinigrin, an index component of cruciferous vegetables, has been reported to have antiobesity effects. In this study, we developed a method for obtaining a BJJ extract with optimized sinigrin content, and investigate the antiobesity properties of the BJJ extract and sinigrin. The optimal extraction conditions for BJJ were found to be with 60% ethanol, at 70°C, for 3 hr. Lipid accumulation and ROS production were significantly suppressed in both the BJJ extract and sinigrin-treated groups. Furthermore, BJJ extract and sinigrin were effectively controlled the expression of proteins that regulate lipid accumulation, fatty acid oxidation, and energy metabolism. Thus, BJJ extract containing sinigrin may be used as a health functional food material. PRACTICAL APPLICATIONS: Brassica juncea has been reported to be rich in flavonoids, polyphenols, and glucosinolate, which are secondary vegetable metabolites. In this study, an extraction method to optimize the content of sinigrin in BJJ was established, and the antiobesity mechanism for the extract was confirmed. Lipid accumulation and ROS production were significantly suppressed in both the BJJ extract and sinigrin-treated groups in the study. It was confirmed that the expression of proteins that regulate lipid accumulation, lipid synthesis, fatty acid oxidation, heat generation, and energy metabolism was effectively controlled by the BJJ extract and sinigrin. Therefore, the ethanol extraction method of this study are considered to be useful for the preparation of extracts using cruciferous vegetables, and BJJ extract containing sinigrin have the potential to be used as a health functional food material for obesity.

Adipogenesis as a Potential Anti-Obesity Target: A Review of Pharmacological Treatment and Natural Products

Obesity is recognized as a severe threat to overall human health and is associated with type 2 diabetes mellitus, dyslipidemia, hypertension, and cardiovascular diseases. Abnormal expansion of white adipose tissue involves increasing the existing adipocytes' cell size or increasing the number through the differentiation of new adipocytes. Adipogenesis is a process of proliferation and differentiation of adipocyte precursor cells in mature adipocytes. As a key process in determining the number of adipocytes, it is a possible therapeutic approach for obesity. Therefore, it is necessary to identify the molecular mechanisms involved in adipogenesis that could serve as suitable therapeutic targets. Reducing bodyweight is regarded as a major health benefit. Limited efficacy and possible side effects and drug interactions of available anti-obesity treatment highlight a constant need for finding novel efficient and safe anti-obesity ingredients. Numerous studies have recently investigated the inhibitory effects of natural products on adipocyte differentiation and lipid accumulation. Possible anti-obesity effects of natural products include the induction of apoptosis, cell-cycle arrest or delayed progression, and interference with transcription factor cascade or intracellular signaling pathways during the early phase of adipogenesis.

Connexin expression decreases during adipogenic differentiation of human adipose-derived mesenchymal stem cells

Adipose-derived stem cells (ASCs) represent a valuable tool for regenerative medicine being able to differentiate toward several cell lines, such as adipocytes, chondrocytes and osteocytes. During ASC adipogenic differentiation, changes in connexin (Cx) expression were evaluated in the present study. Three different Cxs were investigated: Cx43, Cx32 and Cx31.9. Cx43 is the most abundant in human tissues, Cx32 is prevalently found in nervous tissue and Cx31.9 is found at the myocardial level. Human ASCs undergoing adipogenic differentiation were isolated from raw lipoaspirate and characterized as mesenchymal stem cells. After multiple days of culture (1, 7, 14, 21 and 28 days), adipogenic differentiation was assessed by Oil Red O staining and Acetyl-CoA carboxylase (ACC) levels by western blotting. Cx expression was evaluated by western blotting at the same time points. In treated ASCs, lipidic vacuoles were detected from day 7 of treatment. Their number and size progressively increased over the entire period of observation. A parallel increase of ACC expression was also found. Lower levels of Cx expression were detected during adipogenic differentiation. Such decreases were particularly evident for Cx32, already after the first day of treatment. Cx31.9 and Cx43 also decreased, but starting from day 7. Our results suggest that ASCs may initially be equipped with a variety of Cxs, which is not surprising assuming their multipotential differentiation ability. Although some Cxs may be selectively enhanced depending on specific induction strategies toward different tissues, they seem markedly downregulated during adipogenic differentiation.

Genome-Wide DNA Methylation Changes of Perirenal Adipose Tissue in Rabbits Fed a High-Fat Diet

DNA methylation is an epigenetic mechanism that plays an important role in gene regulation without an altered DNA sequence. Previous studies have demonstrated that diet affects obesity by partially mediating DNA methylation. Our study investigated the genome-wide DNA methylation of perirenal adipose tissue in rabbits to identify the epigenetic changes of high-fat diet-mediated obesity. Two libraries were constructed pooling DNA of rabbits fed a standard normal diet (SND) and DNA of rabbits fed a high-fat diet (HFD). Differentially methylated regions (DMRs) were identified using the option of the sliding window method, and online software DAVID Bioinformatics Resources 6.7 was used to perform Gene Ontology (GO) terms and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analysis of DMRs-associated genes. A total of 12,230 DMRs were obtained, of which 2305 (1207 up-regulated, 1098 down-regulated) and 601 (368 up-regulated, 233 down-regulated) of identified DMRs were observed in the gene body and promoter regions, respectively. GO analysis revealed that the DMRs-associated genes were involved in developmental process (GO:0032502), cell differentiation (GO:0030154), and lipid binding (GO:0008289), and KEGG pathway enrichment analysis revealed the DMRs-associated genes were enriched in linoleic acid metabolism (KO00591), DNA replication (KO03030), and MAPK signaling pathway (KO04010). Our study further elucidates the possible functions of DMRs-associated genes in rabbit adipogenesis, contributing to the understanding of HFD-mediated obesity.

Garcinia cambogia suppresses adipogenesis in 3T3-L1 cells by inhibiting p90RSK and Stat3 activation during mitotic clonal expansion

Obesity is associated with an increase in adipose tissue, which is mediated by hyperplasia and hypertrophy. Therefore, inhibiting cell proliferation during mitotic clonal expansion (MCE) is one of the major strategies for preventing obesity. The antagonistic effects of Garcinia cambogia (G. cambogia) on obesity have been studied in animal experimental models. However, the effects of G. cambogia extract on MCE, and the underlying molecular mechanisms, are poorly understood. In this study, 3T3-L1 cells were used to investigate whether G. cambogia extract affected cell proliferation during MCE and to identify target molecules for any anti-adipogenic activity. G. cambogia extract suppressed isobutylmethylxanthine and dexamethasone-and-insulin (MDI)-induced adipogenesis at an early stage by attenuating MCE. In G. cambogia extract-treated preadipocytes, MDI-induced cell proliferation and cell cycle progression were inhibited by G₀ /G₁ arrest due to an increase in p21 and p27 expression, and inhibition of cyclin-dependent kinase 2, cyclin E1 expression, and retinoblastoma (Rb) phosphorylation. In addition, the MDI-induced phosphorylation and subsequent translocation into the nucleus of p90 ribosomal S6 kinase (p90RSK) and signal transducer and activator of transcription (Stat) 3 were suppressed. Specific inhibitors of p90RSK (FMK) and Stat3 (stattic) regulated cell proliferation and adipogenesis. In conclusion, this study demonstrated that G. cambogia extract inhibited MCE by regulating p90RSK, Stat3, and cell cycle proteins, leading to G₀ /G₁ arrest. These findings provide new insight into the mechanism by which G. cambogia suppresses adipocyte differentiation and show that p90RSK is critical for adipogenesis as a new molecular target.

Sinigrin Enhanced Antiasthmatic Effects of Beta Adrenergic Receptors Agonists by Regulating cAMP-Mediated Pathways

Millions of patients suffer from asthma worldwide. However, the first-line drugs used to treat asthma, namely, the beta-adrenergic receptors agonists (β-agonists), are not recommended for use as monotherapy because of their severe dose-related side effects. This limitation has prompted the search for new therapies, which can be used in conjunction with β--agonists so that lower doses can be administered. Sinigrin is a major compound found in many antiasthmatic medicinal plants. In this study, we explored the antiasthmatic activity of sinigrin when used in combination with β-agonists and its underlying mechanism. Sinigrin enhanced the asthma-relieving effects of isoproterenol and reduced the effective isoproterenol dose in an acute-asthma model in guinea pigs. Mechanistically, sinigrin enhanced the cAMP levels induced by β-agonists by inhibiting PDE4. The resulting increase in cAMP levels stimulated the activity of the downstream effector protein kinase A, which would be expected to ultimately induce the relaxation of airway smooth muscle. In conclusion, sinigrin enhances the asthma-relieving effects of β-agonists by regulating the cAMP signaling pathway and represents a potential add-on drug to β-agonists for the treatment of asthma.

Steaming Changes the Composition of Saponins of Panax notoginseng (Burk.) F.H. Chen That Function in Treatment of Hyperlipidemia and Obesity

Saponins of Panax notoginseng (Burk.) F.H. Chen have been classified as a type of composition in functional foods for numerous diseases. However, its mild effects and other characteristics limited clinical applications in diseases. Inspired by "nine steaming and nine processing" of P. notoginseng in traditional Chinese medicine, we developed a "steaming"-mimic protocol, which significantly changed the composition of saponins of P. notoginseng from the original, R1, Rg1, Re, Rb1, and Rd (raw-PNS), to the products after steaming, 20S/R-Rh1, Rk3, Rh4, 20S/R-Rg3, Rk1, and Rg5 (N-PNS). Surprisingly, N-PNS demonstrated promising activities in improving hyperlipidemia and reducing body weight and weight of white adipose tissue and the inhibition of adipogenesis in obese mice. In accordance with the results in vivo, N-PNS remarkably blunted adipogenesis at the early stage of differentiation dose-dependently in vitro. Moreover, we demonstrated that the activity may involve the adenosine monophosphate (AMP)-activated protein kinase (AMPK) signaling pathway by promoting phosphorylation of AMPK^T172 and downregulating its downstream factors: sterol regulatory element binding protein 1c, stearoyl-CoA desaturase 1, and fatty acid synthase. Taken together, the steaming-induced eight compositions of saponins showed a very promising function in improving hyperlipidemia and obesity both in vivo and in vitro, providing fundamental evidence for future study and application in treatment of hyperlipidemia, obesity, and other lipid-related metabolic syndromes.

Uncovering the Role of p38 Family Members in Adipose Tissue Physiology

The complex functions of adipose tissue have been a focus of research interest over the past twenty years. Adipose tissue is not only the main energy storage depot, but also one of the largest endocrine organs in the body and carries out crucial metabolic functions. Moreover, brown and beige adipose depots are major sites of energy expenditure through the activation of adaptive, non-shivering thermogenesis. In recent years, numerous signaling molecules and pathways have emerged as critical regulators of adipose tissue, in both homeostasis and obesity-related disease. Among the best characterized are members of the p38 kinase family. The activity of these kinases has emerged as a key contributor to the biology of the white and brown adipose tissues, and their modulation could provide new therapeutic approaches against obesity. Here, we give an overview of the roles of the distinct p38 family members in adipose tissue, focusing on their actions in adipogenesis, thermogenic activity, and secretory function.

Ezetimibe ameliorates lipid accumulation during adipogenesis by regulating the AMPK-mTORC1 pathway

Adipogenesis, a critical process that converts adipocyte precursors into adipocytes, is considered a potential therapeutic target for the treatment of obesity. Ezetimibe, a drug approved by the United States Food and Drug Administration, is used for the treatment of hypercholesterolemia. Recently, it was reported to ameliorate high fat diet-induced dyslipidemia in mice and reduce lipid accumulation in hepatocytes through the activation of AMPK. However, the anti-adipogenic effects of ezetimibe and the underlying molecular mechanism have not yet been elucidated. Here, we found that ezetimibe reduced lipid accumulation via activating AMPK during the early phase of adipogenesis. We also observed that ezetimibe inhibited peroxisome proliferator-activated receptor γ, which is a major transcription factor of adipogenesis. Furthermore, ezetimibe-mediated AMPK activation reduced lipid accumulation by inhibiting mTORC1 signaling, leading to the downregulation of lipogenesis-related genes. Mitotic clonal expansion, required for adipogenesis, accelerates cell cycle progression and cell proliferation. We additionally observed that ezetimibe prevented the progression of mitotic clonal expansion by arresting the cell cycle at the G0/G1 phase, which was followed by the inhibition of cell proliferation. Collectively, ezetimibe-mediated inhibition of adipogenesis is dependent on the AMPK-mTORC1 pathway. Thus, we suggest that ezetimibe might be a promising drug for the treatment of obesity.

Transcriptomic Analysis Provides Novel Insights into Heat Stress Responses in Sheep

Simple Summary

The general increase in global temperatures has meant that heat stress has become an increasingly significant problem for sheep. This has both direct and indirect impact on their physiological functions, productivity, and health of sheep. Sheep generally live in high-temperature environments; however, the genes and pathways that play regulatory roles in the heat stress responses of sheep remain unclear. In this study, we applied RNA-Seq technology to analyze liver tissues of sheep from heat-stressed and control groups, and screened genes and pathways related to sheep heat stress. This work provides a theoretical foundation for the breeding and production of heat-resistant sheep.

Abstract

With the intensified and large-scale development of sheep husbandry and global warming, sheep heat stress has become an increasingly important issue. However, little is known about the molecular mechanisms related to sheep responses to heat stress. In this study, transcriptomic analysis of liver tissues of sheep in the presence and absence of heat stress was conducted, with the goal of identifying genes and pathways related to regulation when under such stress. After a comparison with the sheep reference genome, 440,226,436 clean reads were obtained from eight libraries. A p-value ≤ 0.05 and fold change ≥ 2 were taken as thresholds for categorizing differentially expressed genes, of which 1137 were identified. The accuracy and reliability of the RNA-Seq results were confirmed by qRT-PCR. The identified differentially expressed genes were significantly associated with 419 GO terms and 51 KEGG pathways, which suggested their participation in biological processes such as response to stress, immunoreaction, and fat metabolism. This study’s results provide a comprehensive overview of sheep heat stress-induced transcriptional expression patterns, laying a foundation for further analysis of the molecular mechanisms of sheep heat stress.

Natural Products and Obesity: A Focus on the Regulation of Mitotic Clonal Expansion during Adipogenesis

Obesity is recognized as a worldwide health crisis. Obesity and its associated health complications such as diabetes, dyslipidemia, hypertension, and cardiovascular diseases impose a big social and economic burden. In an effort to identify safe, efficient, and long-term effective methods to treat obesity, various natural products with potential for inhibiting adipogenesis were revealed. This review aimed to discuss the molecular mechanisms underlying adipogenesis and the inhibitory effects of various phytochemicals, including those from natural sources, on the early stage of adipogenesis. We discuss key steps (proliferation and cell cycle) and their regulators (cell-cycle regulator, transcription factors, and intracellular signaling pathways) at the early stage of adipocyte differentiation as the mechanisms responsible for obesity.

Acrylamide induces adipocyte differentiation and obesity in mice

Obesity is a critical risk factor for various diseases including type II diabetes, cerebral infarction, cardiovascular diseases, and various cancers. Acrylamide (ACR) is present in wide range of foods, including fried potato products, root vegetables, bakery products, chips, cakes, cereals, and coffee. In this study, ACR treatment dramatically increased the accumulation of lipid droplets. We also examined expression levels of peroxisome proliferator-activated receptors γ (PPARγ), CCAAT enhancer binding protein α (c/EBPα), and CCAAT enhancer binding protein β (c/EBPβ) as adipogenic transcription factors for adipocyte differentiation. They were dose-dependently increased by treatment of ACR. Moreover, effects of ACR on mitogen-activated protein kinases (MAPKs) and 5' AMP-activated protein kinase (AMPK)-Acetyl-CoA carboxylase (ACC) activation were investigated. Results also showed that ACR induced phosphorylation of MAPKs and AMPK-ACC. ACR also induced expression of adipocyte fatty acid-binding protein (aP2), lipoprotein lipase (LPL), sterol regulatory element-binding protein (SREBP)-1c, and fatty acid synthase (FAS). Exposure of ACR to high fat diet (HFD)-fed mice significantly increased body weight, organ weight, and fat mass of mice. Collectively, these result showed that ACR can act as an enhancer of adipocyte. Therefore, we suggest that up-regulation of the adipogenesis by ACR may be related to the regulation of the MAPKs and AMPK-ACC pathway.

EGCG stimulates the recruitment of brite adipocytes, suppresses adipogenesis and counteracts TNF-α-triggered insulin resistance in adipocytes

The global rise in obesity and type 2 diabetes has precipitated the need for therapeutic intervention in the arsenal against adiposity. (-)-Epigallocatechin-3-gallate (EGCG), a major nutraceutical component of green tea, has been regarded as a nutraceutical that has powerful antioxidant and anti-obesity bioactivities. In the present study, we showed that EGCG alleviates intracellular lipid accumulation markedly, and the inhibitory effect was largely limited to the early stage of adipocyte differentiation. Consistently, EGCG notably evoked the phosphorylation of AMPK and ACC and blunted the key enzymes of de novo lipogenesis. Interestingly, EGCG elicited iWAT-preadipocyte-derived mature white adipocyte beiging via activating thermogenic gene Ucp1 expression and mitochondrial biogenesis. Furthermore, our results also revealed that EGCG attenuated insulin signaling pathway blockage induced by TNF-α through the abrogation of redox imbalance and mitochondrial dysfunction. These findings indicate that EGCG is capable of suppressing adipogenesis and evoking white adipocyte beiging and therefore it may potentially serve as a novel approach to combat obesity.

Morusin Functions as a Lipogenesis Inhibitor as Well as a Lipolysis Stimulator in Differentiated 3T3-L1 and Primary Adipocytes

Conflicting results for morusin activity during adipogenic differentiation are reported in 3T3-L1 adipocytes and cancer cells. To elucidate the influence of morusin on fat metabolism, their anti-obesity effects and molecular mechanism were investigated in 3T3-L1 cells and primary adipocytes. Morusin at a dose of less than 20 µM does not induce any significant change in the viability of 3T3-L1 adipocytes. The accumulation of intracellular lipid droplets in 3T3-L1 adipocytes stimulated with 0.5 mM 3-isobutyl-1-methylxanthine, 1 µM dexamethasone, 10 µg/mL insulin in DMEM containing 10% FBS (MDI)-significantly reduces in a dose-dependent manner after morusin treatment. The phosphorylation level of members in the MAP kinase signaling pathway under the insulin receptor downstream also decrease significantly in the MDI + morusin-treated group compared to MDI + vehicle-treated group. Also, the expression of adipogenic transcription factors (PPARγ and C/EBPα) and lipogenic proteins (aP2 and FAS) are significantly attenuated by exposure to the compound in MDI-stimulated 3T3-L1 adipocytes. Furthermore, the decrease in the G0/G1 arrest of cell cycle after culturing in MDI medium was dramatically recovered after co-culturing in MDI + 20 µM morusin. Moreover, morusin treatment induces glycerol release in the primary adipocytes of SD rats and enhances lipolytic protein expression (HSL, ATGL, and perilipin) in differentiated 3T3-L1 adipocytes. Overall, the results of the present study provide strong evidence that morusin inhibits adipogenesis by regulating the insulin receptor signaling, cell cycle and adipogenic protein expression as well as stimulating lipolysis by enhancing glycerol release and lipolytic proteins expression.