3,3’-Diindolylmethane suppresses high-fat diet-induced obesity through inhibiting adipogenesis of pre-adipocytes by targeting USP2 activity

Optimization of cultivar, germination time and extraction for radish sprout extract with high sulforaphene content

BACKGROUND

Cruciferous vegetable sprout has been highlighted as a promising functional material rich in bioactive compounds called isothiocyanates (ITCs) and it can be grown in very short periods in controlled indoor farms. However, because ITCs content depends on multiple factors such as cultivar, germination time and myrosinase activity, those variables need to be controlled during germination or extraction to produce functional materials enriched in ITCs. Sulforaphene (SFEN), an ITC found primarily in radishes (Raphanus sativus L.), exerts beneficial effects on obesity. However, the optimal germination and extraction conditions for radish sprout (RSP) to increase SFEN content remain unascertained, and the extract's anti-obesity effect has yet to be evaluated.

RESULTS

The present study found that the SFEN content was highest in purple radish sprout (PRSP) among the six cultivars investigated. Optimal SFEN content occurred after 2 days of PRSP germination (2 days PRSP). To maximize the dry matter yield, total ITCs and SFEN contents in RSP extract, we found the optimal conditions for extracting PRSP [27.5 °C, 60 min, 1:75.52 solute/solvent (w/v), no ascorbic acid] using response surface methodology. Consistent with high SFEN content, 2 days PRSP extract significantly outperformed 3 days or 4 days PRSP extract in inhibiting lipid accumulation in 3T3-L1 cells. Moreover, 2 days PRSP extract suppressed adipogenesis and lipogenesis-related protein expression.

CONCLUSION

Regarding the cultivar, germination time and extraction conditions, optimally produced PRSP extract contains high SFEN content and exerts anti-obesity effects. Thus, we suggest PRSP extract as a potent functional material for obesity prevention. © 2024 Society of Chemical Industry.

Roles of ubiquitin-specific proteases in inflammatory diseases

Ubiquitin-specific proteases (USPs), as one of the deubiquitinating enzymes (DUBs) families, regulate the fate of proteins and signaling pathway transduction by removing ubiquitin chains from the target proteins. USPs are essential for the modulation of a variety of physiological processes, such as DNA repair, cell metabolism and differentiation, epigenetic modulations as well as protein stability. Recently, extensive research has demonstrated that USPs exert a significant impact on innate and adaptive immune reactions, metabolic syndromes, inflammatory disorders, and infection via post-translational modification processes. This review summarizes the important roles of the USPs in the onset and progression of inflammatory diseases, including periodontitis, pneumonia, atherosclerosis, inflammatory bowel disease, sepsis, hepatitis, diabetes, and obesity. Moreover, we highlight a comprehensive overview of the pathogenesis of USPs in these inflammatory diseases as well as post-translational modifications in the inflammatory responses and pave the way for future prospect of targeted therapies in these inflammatory diseases.

FOXO1 regulates the formation of bovine fat by targeting CD36 and STEAP4

Intramuscular fat content is closely related to the quality of beef, where the forkhead box protein O1 (FOXO1) is involved in adipocyte differentiation and lipid metabolism, but the specific mechanism of its involvement is still unclear. In this study, interfering with FOXO1 promoted the G1/S transformation of bovine adipocytes by enhancing the expression of proliferation marker genes PCNA, CDK1, CDK2, CCNA2, CCNB1, and CCNE2, thereby positively regulating the proliferation of bovine adipocytes. Additionally, interfering with FOXO1 negatively regulated the expression of adipogenic differentiation marker genes PPARG and CEBPA, as well as lipid anabolism marker genes ACC, FASN, SCD1, SREBP1, FABP4, ACSL1, LPL, and DGAT1, thus reducing triglyceride (TG) content and inhibiting the generation of lipid droplets in bovine adipocytes. A combination of transcriptomic and metabolomics analyses revealed that FOXO1 could regulate the lipogenesis of cattle by influencing the AMPK and PI3K/AKT pathways. Importantly, chromatin immunoprecipitation (ChIP) and site-directed mutagenesis revealed that FOXO1 could regulate bovine lipogenesis by binding to the promoter regions of the CD36 and STEAP4 genes and affecting their transcriptional activities. These results provide a foundation for studying the role and molecular mechanism of FOXO1 in the bovine adipogenesis.

Indole-3-Carbinol: Occurrence, Health-Beneficial Properties, and Cellular/Molecular Mechanisms

Indole-3-carbinol (I3C) is a bioactive phytochemical abundant in cruciferous vegetables. One of its main in vivo metabolites is 3,3'-diindolylmethane (DIM), formed by the condensation of two molecules of I3C. Both I3C and DIM alter multiple signaling pathways and related molecules controlling diverse cellular events, including oxidation, inflammation, proliferation, differentiation, apoptosis, angiogenesis, and immunity. There is a growing body of evidence from both in vitro and in vivo models that these compounds possess strong potential to prevent several forms of chronic disease such as inflammation, obesity, diabetes, cardiovascular disease, cancer, hypertension, neurodegenerative diseases, and osteoporosis. This article reviews current knowledge of the occurrence of I3C in nature and foods, along with the beneficial effects of I3C and DIM concerning prevention and treatment of human chronic diseases, focusing on preclinical studies and their mechanisms of action at cellular and molecular levels.

Effectiveness of 3,3'-Diindolylmethane Supplements on Favoring the Benign Estrogen Metabolism Pathway and Decreasing Body Fat in Premenopausal Women

The Estrogen Metabolites (2-hydroxyestrogens: 16α-hydroxyestrone) Urine Ratio (EMUR) has been negatively associated with breast cancer; Mexican women have a lower EMUR than other populations. We evaluated the effectiveness of 3,3'-diindolylmethane (DIM) supplementation on increasing EMUR in premenopausal women. A randomized, double-blind clinical trial (NCT02525159 at ClinicalTrial.gov) was carried out on 60 women with an EMUR below 0.9. Patients were assigned randomly to receive a placebo or 75 mg of DIM a day (administered as 300 mg of DIM-BR®) for 30 day. Urine samples were obtained at baseline, at 30 day of supplementation, and 30 day after finishing supplementation. A Mann-Whitney U test was used to compare the EMUR; an ANOVA was used to analyze differences in body composition. EMUR was analyzed using ESTRAMET™ kits. While DIM-treated subjects did not increase their EMUR at 30 day of supplementation (p > 0.05), there was a non-significant positive trend 30 day once supplementation ended (p = 0.06). The DIM group saw a more significant decrease in body fat percentage than the placebo group (p = 0.04). In premenopausal Mexican women, 75 mg of the daily DIM supplement was ineffective in increasing EMUR; further studies are needed to evaluate the effective dosage, time frames, and effect on body fat.

Ubiquitin-Specific Proteases (USPs) and Metabolic Disorders

Ubiquitination and deubiquitination are reversible processes that modify the characteristics of target proteins, including stability, intracellular localization, and enzymatic activity. Ubiquitin-specific proteases (USPs) constitute the largest deubiquitinating enzyme family. To date, accumulating evidence indicates that several USPs positively and negatively affect metabolic diseases. USP22 in pancreatic β-cells, USP2 in adipose tissue macrophages, USP9X, 20, and 33 in myocytes, USP4, 7, 10, and 18 in hepatocytes, and USP2 in hypothalamus improve hyperglycemia, whereas USP19 in adipocytes, USP21 in myocytes, and USP2, 14, and 20 in hepatocytes promote hyperglycemia. In contrast, USP1, 5, 9X, 14, 15, 22, 36, and 48 modulate the progression of diabetic nephropathy, neuropathy, and/or retinopathy. USP4, 10, and 18 in hepatocytes ameliorates non-alcoholic fatty liver disease (NAFLD), while hepatic USP2, 11, 14, 19, and 20 exacerbate it. The roles of USP7 and 22 in hepatic disorders are controversial. USP9X, 14, 17, and 20 in vascular cells are postulated to be determinants of atherosclerosis. Moreover, mutations in the Usp8 and Usp48 loci in pituitary tumors cause Cushing syndrome. This review summarizes the current knowledge about the modulatory roles of USPs in energy metabolic disorders.

Diindolylmethane Inhibits Cadmium-Induced Autophagic Cell Death via Regulation of Oxidative Stress in HEL299 Human Lung Fibroblasts

Cadmium (Cd), a harmful heavy metal, can lead to various pulmonary diseases, including chronic obstructive pulmonary disease (COPD), by inducing cytotoxicity and disturbing redox homeostasis. The aim of the present study was to investigate Cd-mediated cytotoxicity using human lung fibroblasts and the therapeutic potential of 3,3′-diindolylmethane (DIM). Cadmium significantly reduced the cell viability of human embryonic lung (HEL299) cells accompanied by enhanced oxidative stress as evidenced by the increased expression of autophagy-related proteins such as LC3B and p62. However, treatment with DIM significantly suppressed autophagic cell death in Cd-induced HEL299 fibroblasts. In addition, DIM induced antioxidant enzyme activity and decreased intracellular reactive oxygen species (ROS) levels in Cd-damaged HEL299 cells. This study suggests that DIM effectively suppressed Cd-induced lung fibroblast cell death through the upregulation of antioxidant systems and represents a potential agent for the prevention of various diseases related to Cd exposure.

Are isothiocyanates and polyphenols from Brassicaceae vegetables emerging as preventive/therapeutic strategies for NAFLD? The landscape of recent preclinical findings

Nonalcoholic fatty liver disease (NAFLD) is a lipid impairment-related chronic metabolic disease that affects almost 25% of the worldwide population and has become the leading cause of liver transplantation in the United States of America (USA). NAFLD may progress from simple hepatic steatosis (HS) to nonalcoholic steatohepatitis (NASH), which occurs simultaneously in an inflammatory and fibrotic microenvironment and affects approximately 5% of the global population. Recently, NASH has been suggested to be a relevant driver in progressive liver cirrhosis and a population-attributable factor in hepatocellular carcinoma patients. Moreover, predictions show that NAFLD-related annual health costs in the USA have reached ∼$100 bi., but effective therapies are still scarce. Thus, new preventative strategies for this hepatic disease urgently need to be developed. The Brassicaceae vegetable family includes almost 350 genera and 3500 species and these are one of the main types of vegetables harvested and produced worldwide. These vegetables are well-known sources of glucobrassicin-derivative molecules, such as isothiocyanates and phenolic compounds, which have shown antioxidant and antilipogenic effects in preclinical NAFLD data. In this review, we gathered prominent evidence of the in vivo and in vitro effects of these vegetable-derived nutraceutical compounds on the gut-liver-adipose axis, which is a well-known regulator of NAFLD and may represent a new strategy for disease control.

Update of Indoles: Promising molecules for ameliorating metabolic diseases

Obesity and metabolic disorders have gradually become public health-threatening problems. The metabolic disorder is a cluster of complex metabolic abnormalities which are featured by dysfunction in glucose and lipid metabolism, and results from the increasing prevalence of visceral obesity. With the core driving factor of insulin resistance, metabolic disorder mainly includes type 2 diabetes mellitus (T2DM), micro and macro-vascular diseases, non-alcoholic fatty liver disease (NAFLD), dyslipidemia, and the dysfunction of gut microbiota. Strategies and therapeutic attention are demanded to decrease the high risk of metabolic diseases, from lifestyle changes to drug treatment, especially herbal medicines. Indole is a parent substance of numerous bioactive compounds, and itself can be produced by tryptophan catabolism to stimulate glucagon-like peptide-1 (GLP-1) secretion and inhibit the development of obesity. In addition, in heterocycles drug discovery, the indole scaffold is primarily found in natural compounds with versatile biological activity and plays a prominent role in drug molecules synthesis. In recent decades, plenty of natural or synthesized indole deriviatives have been investigated and elucidated to exert effects on regulating glucose hemeostasis and lipd metabolism. The aim of this review is to trace and emphasize the compounds containing indole scaffold that possess immense potency on preventing metabolic disorders, particularly T2DM, obesity and NAFLD, along with the underlying molecular mechanisms, therefore facilitate a better comprehension of their druggability and application in metabolic diseases.

Integrated Study of Transcriptome-wide m6A Methylome Reveals Novel Insights Into the Character and Function of m6A Methylation During Yak Adipocyte Differentiation

Yak (Bos grunniens) is considered an iconic symbol of Tibet and high altitude, but they suffer from malnutrition during the cold season that challenges the metabolism of energy. Adipocytes perform a crucial role in maintaining the energy balance, and adipocyte differentiation is a complex process involving multiple changes in the expression of genes. N ⁶-methyladenosine (m⁶A) plays a dynamic role in post-transcription gene expression regulation as the most widespread mRNA modification of the higher eukaryotes. However, currently there is no research existing on the m⁶A transcriptome-wide map of bovine animals and their potential biological functions in adipocyte differentiation. Therefore, we performed methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA sequencing (RNA-seq) to determine the distinctions in m⁶A methylation and gene expression during yak adipocyte differentiation. In yak adipocyte and preadipocyte the content of m⁶A and m⁶A-associated enzymes was substantially different. In the two groups, a total of 14,710 m⁶A peaks and 13,388 m⁶A peaks were identified. For the most part, m⁶A peaks were enriched in stop codons, 3'-untranslated regions, and coding regions with consensus motifs of GGACU. The functional enrichment exploration displayed that differentially methylated genes participated in some of the pathways associated with adipogenic metabolism, and several candidate genes (KLF9, FOXO1, ZNF395, and UHRF1) were involved in these pathways. In addition to that, there was a positive association between m⁶A abundance and levels of gene expression, which displayed that m⁶A may play a vital role in modulating gene expression during yak adipocyte differentiation. Further, in the adipocyte group, several methylation gene protein expression levels were significantly higher than in preadipocytes. In short, it can be concluded that the current study provides a comprehensive explanation of the m⁶A features in the yak transcriptome, offering in-depth insights into m⁶A topology and associated molecular mechanisms underlying bovine adipocyte differentiation, which might be helpful for further understanding its mechanisms.

Improving the Health-Benefits of Kales (Brassica oleracea L. var. acephala DC) through the Application of Controlled Abiotic Stresses: A Review

Kale (Brassica oleracea L. var. acephala DC) is a popular cruciferous vegetable originating from Central Asia, and is well known for its abundant bioactive compounds. This review discusses the main kale phytochemicals and emphasizes molecules of nutraceutical interest, including phenolics, carotenoids, and glucosinolates. The preventive and therapeutic properties of kale against chronic and degenerative diseases are highlighted according to the most recent in vitro, in vivo, and clinical studies reported. Likewise, it is well known that the application of controlled abiotic stresses can be used as an effective tool to increase the content of phytochemicals with health-promoting properties. In this context, the effect of different abiotic stresses (saline, exogenous phytohormones, drought, temperature, and radiation) on the accumulation of secondary metabolites in kale is also presented. The information reviewed in this article can be used as a starting point to further validate through bioassays the effects of abiotically stressed kale on the prevention and treatment of chronic and degenerative diseases.

Mechanisms Underlying Biological Effects of Cruciferous Glucosinolate-Derived Isothiocyanates/Indoles: A Focus on Metabolic Syndrome

An inverse correlation between vegetable consumption and the incidence of cancer has long been described. This protective effect is stronger when cruciferous vegetables are specifically consumed. The beneficial properties of vegetables are attributed to their bioactive components like fiber, antioxidants vitamins, antioxidants, minerals, and phenolic compounds. Cruciferous vegetables contain all these molecules; however, what makes them different are their sulfurous components, called glucosinolates, responsible for their special smell and taste. Glucosinolates are inactive biologically in the organism but are hydrolyzed by the enzyme myrosinase released as a result of chewing, leading to the formation of active derivatives such as isothiocyanates and indoles. A considerable number of in vitro and in vivo studies have reported that isothiocyanates and indoles elicit chemopreventive potency through multiple mechanisms that include modulation of phases I and II detoxification pathway enzymes, regulation of cell cycle arrest, and control of cell growth, induction of apoptosis, antioxidant activity, anti-angiogenic effects, and epigenetic regulation. Nuclear erythroid 2-related factor 2 (Nrf2) and Nuclear factor-κB (NF-κB) are key and central regulators in all these processes with a main role in oxidative stress and inflammation control. It has been described that isothiocyanates and indoles regulate their activity directly and indirectly. Today, the metabolic syndrome (central obesity, insulin resistance, hyperlipidemia, and hypertension) is responsible for a majority of deaths worldwide. All components of metabolic syndrome are characterized by chronic inflammation with deregulation of the PI3K/AKT/mTOR, MAPK/EKR/JNK, Nrf2, and NF-κB signaling pathways. The effects of GLSs derivatives controlling these pathways have been widely described in relation to cancer. Changes in food consumption patterns observed in the last decades to higher consumption of ultra-processed foods, with elevation in simple sugar and saturated fat contents and lower consumption of vegetables and fruits have been directly correlated with metabolic syndrome prevalence. In this review, it is summarized the knowledge regarding the mechanisms by which cruciferous glucosinolate derivatives (isothiocyanates and indoles) directly and indirectly regulate these pathways. However, the review places a special focus on the knowledge of the effects of glucosinolates derivatives in metabolic syndrome, since this has not been reviewed before.

Effects and mechanisms of edible and medicinal plants on obesity: an updated review

In recent years, obesity has become a global public health issue. It is closely associated with the occurrence of several chronic diseases, such as diabetes and cardiovascular diseases. Some edible and medicinal plants show anti-obesity activity, such as fruits, vegetables, spices, legumes, edible flowers, mushrooms, and medicinal plants. Numerous studies have indicated that these plants are potential candidates for the prevention and management of obesity. The major anti-obesity mechanisms of plants include suppressing appetite, reducing the absorption of lipids and carbohydrates, inhibiting adipogenesis and lipogenesis, regulating lipid metabolism, increasing energy expenditure, regulating gut microbiota, and improving obesity-related inflammation. In this review, the anti-obesity activity of edible and medicinal plants was summarized based on epidemiological, experimental, and clinical studies, with related mechanisms discussed, which provided the basis for the research and development of slimming products. Further studies should focus on the exploration of safer plants with anti-obesity activity and the identification of specific anti-obesity mechanisms.

Sulforaphene Suppresses Adipocyte Differentiation via Induction of Post-Translational Degradation of CCAAT/Enhancer Binding Protein Beta (C/EBPβ)

Adipocyte differentiation (adipogenesis) is a crucial process that determines the total number and size of mature adipocytes that will develop. In this study, the anti-adipogenic effect of sulforaphene (SFEN), a dietary isothiocyanate (ITC) derived from radish, is investigated both in 3T3-L1 pre-adipocytes and in human adipose tissue-derived stem cells. The results revealed that SFEN significantly inhibit adipogenic cocktail-induced adipocyte differentiation and lipid accumulation at the early stage of adipogenesis. Additionally, the effects are more potent compared to those of other ITCs derived from various cruciferous vegetables. As a related molecular mechanism of action, SFEN promotes the post-translational degradation of CCAAT/enhancer-binding protein (C/EBP) β by decreasing the stability of C/EBPβ, which is responsible for decreasing the expression of master regulatory proteins such as peroxisome proliferator-activated receptor γ and C/EBPα. Collectively, these results suggest that the intake of SFEN-enriched natural materials could be helpful as a strategy for preventing obesity.

Cyclin D degradation by E3 ligases in cancer progression and treatment

D cyclins include three isoforms: D1, D2, and D3. D cyclins heterodimerize with cyclin-dependent kinase 4/6 (CDK4/6) to form kinase complexes that can phosphorylate and inactivate Rb. Inactivation of Rb triggers the activation of E2F transcription factors, which in turn regulate the expression of genes whose products drive cell cycle progression. Because D-type cyclins function as mitogenic sensors that link growth factor signaling directly with G₁ phase progression, it is not surprising that D cyclin accumulation is dysregulated in a variety of human tumors. Elevated expression of D cyclins results from gene amplification, increased gene transcription and protein translation, decreased microRNA levels, and inefficiency or loss of ubiquitylation-mediated protein degradation. This review focuses on the clinicopathological importance of D cyclins, how dysregulation of Ubiquitin-Proteasome System (UPS) contributes to the overexpression of D cyclins, and the therapeutic potential through targeting D cyclin-related machinery in human tumors.

Patchouli Alcohol, a Compound from Pogostemon cablin, Inhibits Obesity

Obesity predisposes people to a variety of chronic metabolic diseases. Identification of natural factors that prevent the development of obesity is likely to be the most successful means of ameliorating the current obesity epidemic. Patchouli alcohol is a sesquiterpene alcohol found in Pogostemon cablin and possesses health benefit activities. This study was designed to examine if patchouli alcohol affects adipogenesis, and investigates the underlying mechanisms whereby patchouli alcohol exerts antiobesity effect. 3T3-L1 adipocytes were differentiated with treatment of different concentrations of patchouli alcohol. An in vivo study was performed to test the effect of patchouli alcohol gavage on a high-fat diet (HFD)-induced obesity. Treatment of patchouli alcohol reduced lipid accumulation in 3T3-L1 adipocytes in a dose-dependent manner without toxicity. Regarding mechanism, treatment of patchouli alcohol reduced expression of peroxisome proliferator-activated receptor-gamma (PPARγ) and CCAAT-enhancer-binding protein-alpha (C/EBPα) and increased expression of total and active β-catenin in 3T3-L1 adipocytes. Oral gavage of patchouli alcohol led to a significant reduction of body weight and fat accumulation in the mice fed with HFD. Transcriptome analysis indicates that smad7 is most highly activated gene in patchouli alcohol-treated 3T3-L1 cells. Patchouli alcohol possesses health benefit effect through inhibiting adipogenesis and fat tissue development.

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

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

3,3'-Diindolylmethane Enhances Glucose Uptake Through Activation of Insulin Signaling in 3T3-L1 Adipocytes

OBJECTIVE

Indole-3-carbinol (I3C), a naturally occurring compound found in cruciferous vegetables, and its metabolite 3,3'-diindolylmethane (DIM) reduce body mass and serum glucose levels in high-fat-diet-induced obese mice. This study aimed to determine whether I3C or DIM could increase glucose uptake via enhanced insulin sensitivity in 3T3-L1 adipocytes, as well as the mechanism involved.

METHODS

3T3-L1 preadipocytes were differentiated by using a mixture of adipogenic inducers, including a suboptimal concentration of insulin.

RESULTS

DIM, but not I3C, increased adipocyte differentiation through upregulation of peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding protein α. DIM also enhanced glucose uptake by increasing expression of glucose transporter 4 in adipocytes. This was associated with DIM-enhanced phosphorylation of the signaling intermediates Akt, insulin receptor substrate-1, and insulin receptor early in differentiation.

CONCLUSIONS

Our findings suggest that DIM may improve insulin sensitivity through the activation of the insulin signaling pathway, leading to enhanced glucose uptake.