ABSTRACT
Obesity, a major public health problem, causes numerous complications that threaten human health and increase the socioeconomic burden. The pathophysiology of obesity is primarily attributed to lipid metabolism disorders. Conventional anti-obesity medications have a high abuse potential and frequently deliver insufficient efficacy and have negative side-effects. Hence, functional foods are regarded as effective alternatives to address obesity. Coffee, tea, and cocoa, three widely consumed beverages, have long been considered to have the potential to prevent obesity, and several studies have focused on their intrinsic molecular mechanisms in past few years. Therefore, in this review, we discuss the mechanisms by which the bioactive ingredients in these three beverages counteract obesity from the aspects of adipogenesis, lipolysis, and energy expenditure (thermogenesis). The future prospects and challenges for coffee, tea, and cocoa as functional products for the treatment of obesity are also discussed, which can be pursued for future drug development and prevention strategies against obesity.
ABSTRACT
Ovarian cancer is the leading cause of death from gynecologic illnesses worldwide. High-grade serous ovarian cancer (HGSOC) is a gynecological tumor that accounts for roughly 70% of ovarian cancer deaths in women. Runt-related transcription factor 1(RUNX1) proteins were identified with overexpression in the HGSOC. However, the roles of RUNX1 in the development of HGSOC are poorly understood. In this study, combined with whole-transcriptome analysis and multiple research methods, RUNX1 was identified as vital in developing HGSOC. RUNX1 knockdown inhibits the physiological function of ovarian cancer cells and regulates apoptosis through the FOXO1-Bcl2 axis. Down-regulated RUNX1 impairs EMT function through the EGFR-AKT-STAT3 axis signaling. In addition, RUNX1 knockdown can significantly increase the sensitivity to clinical drug therapy for ovarian cancer. It is strongly suggested that RUNX1 work as a potential diagnostic and therapeutic target for HGSOC patients with better prognoses and treatment options. It is possible to generate novel potential targeted therapy strategies and translational applications for serous ovarian carcinoma patients with better clinical outcomes.
Subject(s)
Core Binding Factor Alpha 2 Subunit , Ovarian Neoplasms , Humans , Female , Core Binding Factor Alpha 2 Subunit/genetics , Core Binding Factor Alpha 2 Subunit/therapeutic use , Cell Line, Tumor , Ovarian Neoplasms/drug therapy , Prognosis , Apoptosis/geneticsABSTRACT
The transient receptor potential canonical channel 5 (TRPC5), a member of the TRPC family, plays a crucial role in the regulation of various physiological activities and diseases, including those related to the central nervous system, cardiovascular system, kidney, and cancer. As a nonselective cation channel, TRPC5 mainly controls the influx of extracellular Ca2+ into cells, thereby modulating cellular depolarization and intracellular ion concentration. Inhibition of TRPC5 by small molecules presents a promising approach for the treatment of TRPC5-associated diseases. In this study, we conducted a comprehensive virtual screening of more than 1.5 million molecules from the Chemdiv database (https://www.chemdiv.com) to identify potential inhibitors of hTRPC5, utilizing the published structures and binding sites of hTRPC5 as a basis. Lipinski's rule, Veber's rule, PAINS filters, pharmacophore analysis, molecular docking, ADMET evaluation and cluster analysis methods were applied for the screening. From this rigorous screening process, 18 candidates exhibiting higher affinities to hTRPC5 were subsequently evaluated for their inhibitory effects on Ca2+ influx using a fluorescence-based assay. Notably, two molecules, namely SML-1 and SML-13, demonstrated significant inhibition of intracellular Ca2+ levels in hTRPC5-overexpressing HEK 293T cells, with IC50 values of 10.2 µM and 10.3 µM, respectively. These findings highlight SML-1 and SML-13 as potential lead molecules for the development of therapeutics targeting hTRPC5 and its associated physiological activities and diseases.
ABSTRACT
As a global epidemic disease, obesity causes dysfunction of glucose and lipid metabolism leading to persistently high morbidity and mortality. Given the difficulty to achieve and maintain weight loss through controlling diet and physical exercise, pharmacotherapy is considered an effective treatment for obesity. This investigation revealed that alisol B, a triterpene monomer isolated from the classical Chinese medicine Alisma orientale (Sam.) Juzep, functioned in suppressing adipogenesis and reducing the mass of subcutaneous adipose tissue, resulting in the reduction of weight gain, and improvements of hyperglycemia, hyperlipidemia, and insulin resistance in HFD-induced obese mice. In consistent to the results, alisol B also significantly inhibited adipocyte differentiation and maturation in vitro. Furthermore, our data revealed that the effects of alisol B on adipogenesis were mediated by LKB1-AMPK signaling pathway. In total, alisol B could be a potential lead compound which contributes to the improvement of obesity-related metabolic disorders.
Subject(s)
AMP-Activated Protein Kinases , Obesity , Mice , Animals , Obesity/drug therapy , Obesity/etiology , Subcutaneous Fat , Cholestenones/pharmacology , Cholestenones/therapeutic use , Adipogenesis , Diet, High-Fat/adverse effects , Adipose Tissue , Mice, Inbred C57BLABSTRACT
Previous studies have shown that coffee has a role in regulating lipid metabolism. However, the active compounds and pharmacological mechanism(s) are still unclear. Here, four new coffee diterpenoids (1-4) were identified from roasted arabica coffee (Coffea arabica L.) beans, and together with 31 known coffee diterpenoids (5-35), their bioactivities in the regulation of lipid content in white adipocytes were evaluated. Based on their structures and correlated bioactivities, we proposed that the α,ß-unsaturated-γ-lactone moiety and hydroxyl group at C-3 are required for the bioactivity. Furthermore, the pharmacological approaches revealed that the active new diterpenoid, dehydrocaffarolide B, inhibited the Akt/mTOR/GSK3ß pathway and arrested cells in the G0/G1 phase of the mitotic clonal expansion process during the adipocyte differentiation and maturation, eventually resulting in the blunting of lipid accumulation in the adipocytes. Collectively, our findings identified four new diterpenoids of arabica coffee and elucidated a mechanism of an active lactone-type diterpenoid in the regulation of lipid content in white adipocytes.
Subject(s)
Coffea , Coffea/chemistry , Coffee/chemistry , Adipocytes, White , Food Handling/methods , Seeds/chemistry , Lipids/analysisABSTRACT
Receptor for activated C kinase 1 (RACK1) is a versatile protein involved in multiple biological processes. In a previous study by Zhao et al., hepatic RACK1 deletion in mice led to an inhibition of autophagy, blocked autophagy-dependent lipolysis, and caused steatosis. Using the same mouse model (RACK1hep-/-), we revealed new roles of RACK1 in maintaining bile acid homeostasis and hepatic glucose uptake, which further affected circulatory lipid and glucose levels. To be specific, even under hepatic steatosis, the plasma lipids were generally reduced in RACK1hep-/- mouse, which was due to the suppression of intestinal lipid absorption. Accordingly, a decrease in total bile acid level was found in RACK1hep-/- livers, gallbladders, and small intestine tissues, and specific decrease of 12-hydroxylated bile acids was detected by liquid chromatography-mass spectrometry. Consistently, reduced expression of CYP8B1 was found. A decrease in hepatic glycogen storage was also observed, which might be due to the inhibited glucose uptake by GLUT2 insufficiency. Interestingly, RACK1-KO-inducing hepatic steatosis did not raise insulin resistance (IR) nor IR-inducing factors like endoplasmic reticulum stress and inflammation. In summary, this study uncovers that hepatic RACK1 might be required in maintaining bile acid homeostasis and glucose uptake in hepatocytes. This study also provides an additional case of hepatic steatosis disassociation with insulin resistance.
Subject(s)
Fatty Liver , Insulin Resistance , Animals , Bile Acids and Salts , Fatty Liver/metabolism , Glucose/metabolism , Homeostasis , Insulin Resistance/genetics , Lipids , Liver/metabolism , Mice , Mice, Knockout , Receptors for Activated C Kinase/genetics , Receptors for Activated C Kinase/metabolismABSTRACT
The abnormal proliferation and hypertrophy of adipocytes mediate the expansion of adipose tissue and then cause obesity-related diseases. Theoretically, an approach for preventing and curing obesity is to inhibit cell proliferation during the mitotic clonal expansion (MCE) progression of adipocyte differentiation. Polycyclic polyprenylated acylphloroglucinols (PPAPs) are mainly found from Hypericum and Garcinia genus, which have been reported to have various biological activities such as anti-depressant, anti-oxidant, and anti-tumor. Previously, our group has reported that adamantane-type PPAPs exhibited blunting activity in adipogenesis. In this study, another six adamantane PPAPs were screened to investigate their anti-adipogenesis activities and then discussed the structure-activity relationship. Particularly, sampsonione F, one of the PPAPs dramatically suppressed adipogenesis dose-dependently in vitro, along with decreased expressions of C/EBPß, C/EBPα, PPARγ, FABP4, and FAS. Moreover, sampsonione F upregulated the expression of p27 by activating p53 pathway and then downregulated the expressions of key regulators during G1/S phase arrest. Our data support that sampsonione F suppressed adipogenesis by activating p53 pathway, regulating cyclins, and resulting in G1/S phase arrest during the MCE progression of adipogenesis. This work provides a new adamantane-type PPAPs in the regulation of adipogenesis and extends our knowledges on the mechanism of the type PPAPs in regulation of adipogenesis.
Subject(s)
Adamantane , Adipocytes , Adipogenesis , Cell Differentiation , Tumor Suppressor Protein p53 , 3T3-L1 Cells , Adamantane/analogs & derivatives , Adamantane/pharmacology , Adipocytes/cytology , Adipocytes/drug effects , Adipogenesis/drug effects , Animals , Mice , Mitosis , Obesity , Phytochemicals/pharmacology , Tumor Suppressor Protein p53/metabolismABSTRACT
Our previous research has shown that lanostane triterpenoids from Ganoderma applanatum exhibit significant anti-adipogenesis effects. In order to obtain more structurally diverse lanostane triterpenoids to establish a structure-activity relationship, we continued the study of lanostane triterpenoids from the fruiting bodies of G. applanatum, and forty highly oxygenated lanostane-type triterpenoinds (1-40), including sixteen new compounds (1-16), were isolated. Their structures were elucidated using NMR spectra, X-ray crystallographic analysis, and Mosher's method. In addition, some of their parts were evaluated to determine their anti-adipogenesis activities in the 3T3-L1 cell model. The results showed that compounds 16, 22, 28, and 32 exhibited stronger anti-adipogenesis effects than the positive control (LiCl, 20 mM) at the concentration of 20 µM. Compounds 15 and 20 could significantly reduce the lipid accumulation during the differentiation process of 3T3-L1 cells, comparable to the untreated group. Their IC50 values were 6.42 and 5.39 µM, respectively. The combined results of our previous and present studies allow us to establish a structure-activity relationship of lanostane triterpenoids, indicating that the A-seco-23â26 lactone skeleton could play a key role in anti-adipogenesis activity.
ABSTRACT
Ischemic cardiomyopathy is the most frequent type of heart disease, and it is a major cause of myocardial infarction (MI) and heart failure (HF), both of which require expensive medical treatment. Precise biomarkers and therapy targets must be developed to enhance improve diagnosis and treatment. In this study, the transcriptional profiles of 313 patients' left ventricle biopsies were obtained from the PubMed database, and functional genes that were significantly related to ischemic cardiomyopathy were screened using the Weighted Gene Co-Expression Network Analysis and protein-protein interaction (PPI) networks enrichment analysis. The rat myocardial infarction model was developed to validate these findings. Finally, the putative signature genes were blasted through the common Cardiovascular Disease Knowledge Portal to explore if they were associated with cardiovascular disorder. Three interferon stimulated genes (IFIT2, IFIT3 and IFI44L), as well as key pathways, have been identified as potential biomarkers and therapeutic targets for ischemic cardiomyopathy, and their alternations or mutations have been proven to be strongly linked to cardiac disorders. These novel signature genes could be utilized as bio-markers or potential therapeutic objectives in precise clinical diagnosis and treatment of ischemic cardiomyopathy.
Subject(s)
Apoptosis Regulatory Proteins/genetics , Cardiomyopathies/genetics , Interferons/genetics , Myocardial Infarction/genetics , RNA-Binding Proteins/genetics , Tumor Suppressor Proteins/genetics , Animals , Biomarkers , Cardiomyopathies/pathology , Disease Models, Animal , Gene Regulatory Networks , Heart Ventricles/pathology , Humans , Interferons/metabolism , Intracellular Signaling Peptides and Proteins/genetics , Male , Metoprolol/pharmacology , Myocardial Infarction/drug therapy , Myocardial Infarction/physiopathology , Myocardial Ischemia/genetics , Myocytes, Cardiac/pathology , Protein Interaction Maps/genetics , Rats, Sprague-Dawley , Ventricular Function, LeftABSTRACT
Four pairs of novel meroterpenoid dimers, (±)-applandimeric acids A-D (1-4) with an unprecedented spiro[furo[3,2-b]benzofuran-3,2'-indene] core were isolated from the fruiting bodies of Ganoderma applanatum. Their planar structures were unambiguously determined via extensive spectroscopic analysis. Their relative and absolute configurations were confirmed through calculated internuclear distance, coupling constant, 13C NMR with DP4 + analysis and electronic circular dichroism (ECD). Furthermore, the molecular docking-based method was used to evaluate their interaction with formyl peptide receptor 2 (FPR2) associated with inflammation. Interestingly, (±)-applandimeric acid D (4) can bond with FPR2 by some key hydrogen bonds. Furthermore, an in vitro bioassay verified that 4 can inhibit the expression of FPR2 with IC50 value of 7.93 µM. In addition, compared to the positive control LiCl (20 mM), 4 showed comparable anti-lipogenesis activity at the concentration of 20 µM. Meanwhile, 4 can suppress the protein levels of peroxisome proliferators-activated receptor-γ (PPAR-γ), CCAAT/enhancer-binding protein-ß (C/EBP-ß), adipocyte fatty acid-binding protein 4 (FABP4), and fatty acid synthase (FAS) through activating AMP-activated protein kinase (AMPK) signaling pathway. Thus, our findings indicate that compound 4 could be a lead compound to treat obesity and obesity-related diseases by inhibiting lipid accumulation in adipocyte and alleviating inflammation.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Ganoderma/chemistry , Lipogenesis/drug effects , Receptors, Formyl Peptide/antagonists & inhibitors , Receptors, Lipoxin/antagonists & inhibitors , Terpenes/pharmacology , 3T3-L1 Cells , Animals , Anti-Inflammatory Agents, Non-Steroidal/chemistry , Anti-Inflammatory Agents, Non-Steroidal/isolation & purification , Cell Proliferation/drug effects , Cell Survival/drug effects , Dose-Response Relationship, Drug , HEK293 Cells , Humans , Mice , Molecular Dynamics Simulation , Molecular Structure , PPAR gamma/antagonists & inhibitors , PPAR gamma/metabolism , Receptors, Formyl Peptide/genetics , Receptors, Formyl Peptide/metabolism , Receptors, Lipoxin/genetics , Receptors, Lipoxin/metabolism , Structure-Activity Relationship , Terpenes/chemistry , Terpenes/isolation & purificationABSTRACT
Previously, we have demonstrated the antiadipogenic benefits of Ganoderma triterpenoids (GTs), which indicated GTs have potential therapeutic implications for obesity. In this study, the EtOAc extract of Ganoderma applanatum was further phytochemically investigated for searching new antiadipogenic agents, which led to the isolation of a total of 15 highly oxygenated lanostane triterpenoids, including 9 new compounds (1-9) and 6 known analogues (10-15). Structurally, ganodapplanoic acids A and B (1, 2) are two rearranged 6/6/5/6-fused lanostane-type triterpenoids with an unusual C-13/C-15 oxygen bridge moiety. In addition, the EtOAc extract (GAE) and isolates (1-4,6-15) were assayed for their antiadipogenic effects in 3T3-L1 adipocytes. The results revealed that compound 9 effectively repressed adipogenesis through down-regulating the expression of major proteins (PPARγ, CEBPß and FAS) involving differentiation and adipogenesis in 3T3-L1 adipocytes. Thus, the present study further demonstrated the antiadipogenic potential of GTs and provided a possible perspective for obesity treatment.
Subject(s)
Adipocytes/drug effects , Adipogenesis/drug effects , Anti-Obesity Agents/pharmacology , Ganoderma/chemistry , Triterpenes/pharmacology , 3T3-L1 Cells , Animals , Anti-Obesity Agents/chemistry , Anti-Obesity Agents/isolation & purification , Cell Differentiation/drug effects , Cell Survival/drug effects , Cells, Cultured , Dose-Response Relationship, Drug , Lipids/analysis , Mice , Molecular Structure , Structure-Activity Relationship , Triterpenes/chemistry , Triterpenes/isolation & purificationABSTRACT
Homoharringtonine (HHT), a natural alkaloid derived from the cephalotaxus, exhibited its anti-cancer effects in hematological malignancies clinically. However, its pesticide effects and mechanisms in treating solid tumors remain unclear. In this study, we found that HHT was capable of inhibiting tumor growth after 5-days treatment of breast cancer cells, MCF-7, in vivo. Furthemore, HHT also significantly inhibited the cancer cell growth and induced cell apoptosis in vitro. miRNA sequencing proved miR-18a-3p was noticeably downregulated in the cells after HHT treatment. Moreover, downregulating miR-18a-3p increased HHT-induced cell apoptosis; our data supported that HHT suppressed miR-18a-3p expression and inhibited tumorigenesis might via AKT-mTOR signaling pathway. In conclusion: our study proved that HHT suppressed breast cancer cell growth and promoted apoptosis mediated by regulating of the miR-18a-3p-AKT-mTOR signaling pathway, HHT may be a promising antitumor agent in breast cancer treatment.
Subject(s)
Breast Neoplasms/drug therapy , Homoharringtonine/therapeutic use , MicroRNAs/metabolism , Proto-Oncogene Proteins c-akt/metabolism , TOR Serine-Threonine Kinases/metabolism , Apoptosis/drug effects , Breast Neoplasms/metabolism , Drug Screening Assays, Antitumor , Homoharringtonine/pharmacology , Humans , MCF-7 Cells , Signal Transduction/drug effectsABSTRACT
Hypersubones D-H (1-5), five new polycyclic polyprenylated acylphloroglucinols (PPAPs) type metabolites with intriguing adamantane and homo-adamantane skeletons, were characterized from aerial parts of Hypericum subsessile. Compounds 1-2 were elucidated to share an adamantane core with 28,29-expoxide moiety, while 3-5 were homo-adamantane type PPAPs sharing a1,2-dioxepane ring system. Their structures were determined on the basis of comprehensive NMR and MS spectroscopic data.The anti-adipogenesis activities of these isolates were evaluated through employing 3T3-L1 cells as an in vitro system using oil red O staining, and compounds 1, 2 and 5 were able to significant inhibit the adipocyte differentiation, which implied that these compounds possessed anti-adipogenic activity.
Subject(s)
Adamantane/pharmacology , Adipocytes/drug effects , Hypericum/chemistry , 3T3-L1 Cells , Adamantane/isolation & purification , Animals , Cell Differentiation/drug effects , China , Mice , Molecular Structure , Phytochemicals/isolation & purification , Phytochemicals/pharmacology , Plant Components, Aerial/chemistryABSTRACT
Ganoderma triterpenoids (GTs), a class of major active constituents in Ganoderma species, play an important role in the anti-obesity effect of Ganoderma fungi. In the study, seventeen new highly oxygenated lanostane triterpenoids, ganoapplanoids A-Q (1-17), together with five previously reported compounds (18-22), were isolated from the fruiting bodies of Ganoderma applanatum. Their structures were confirmed by comprehensive spectroscopic analyses, single-crystal X-ray diffraction and Mo2(OAc)4 induced CD cotton effect. Structurally, compound 6 represents the first example of 2-norlanostane triterpenoid possessing an unusual semiacetal moiety. Furthermore, isolates (1-5, 7-11, 13-22, 3a) were evaluated for regulatory effects on lipid accumulation by 3T3-L1 adipocytes model. Among them, compounds 11 and 17 exhibited significant potency in blunted adipogenesis activities dose-dependently. Meanwhile, compounds 11 and 17 reduced triglyceride (TG) and total cholesterol (TC) levels in the adipocytes. These results supported that the highly oxygenated lanostane triterpenoids from G. applanatum may serve as agents for inhibiting the lipid accumulation in adipocytes and the G. applanatum provided an important source for searching new drugs to treat obesity.
Subject(s)
Adipocytes/drug effects , Ganoderma/chemistry , Lanosterol/pharmacology , Lipids/antagonists & inhibitors , Oxygen/chemistry , Triterpenes/pharmacology , 3T3-L1 Cells , Adipocytes/metabolism , Animals , Cell Survival/drug effects , Cells, Cultured , Dose-Response Relationship, Drug , Lanosterol/analogs & derivatives , Lanosterol/chemistry , Mice , Molecular Structure , Structure-Activity Relationship , Triterpenes/chemistry , Triterpenes/isolation & purificationABSTRACT
In the original publication of this article, we found an error under the section "Introduction". The first sentence of the fourth paragraph appears incorrectly. The corrected sentence is given below. Eriocalyxin B, isolated and identified in 1982 [1], is the major component in Chinese plant Isodon eriocalyx (Dunn.) Hara (family Lamiaceae) showing many pharmacological activities, such as inhibiting inflammatory response, regulating immune cell differentiation, inhibiting tumor cells proliferation, causing cell cycle arrest affecting angiogenesis and promoting cancer cells apoptosis.
ABSTRACT
Adamantane polycyclic polyprenylated acylphloroglucinols (PPAPs) with caged architecture, a special class of hybrid natural products, is specifically rich in the plant family Guttiferae, especially Hypericum or Garcinia genus. Hypersampsone P is one of Adamantane PPAPs compounds extracted from Hypericum subsessile. Here we have chosen, screened ten PPAPs and identified one of them showed an activity in inhibiting of adipocytes differentiation. Particularly, the compound, hypersampsone P, blunted the adipocyte differentiation dose-dependently. Moreover, hypersampsone P down-regulated the expressions of several key regulators for adipogenesis, including PPARγ and FABP4. The treatment of cells at the early stage of adipogenesis by hypersampsone P induced the greatest blunting of adipocyte differentiation and the effect might be involved in the LKB1-AMPK signaling pathway.
ABSTRACT
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 AMPKT172 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.
Subject(s)
Drugs, Chinese Herbal/administration & dosage , Hyperlipidemias/drug therapy , Obesity/drug therapy , Panax notoginseng/chemistry , Saponins/administration & dosage , AMP-Activated Protein Kinases/genetics , AMP-Activated Protein Kinases/metabolism , Animals , Drugs, Chinese Herbal/chemistry , Humans , Hyperlipidemias/genetics , Hyperlipidemias/metabolism , Male , Mice , Mice, Inbred C57BL , Obesity/genetics , Obesity/metabolism , Phytotherapy , Saponins/chemistry , Sterol Regulatory Element Binding Protein 1/geneticsABSTRACT
Eriocalyxin B, an ent-Kaurene diterpenoid extracted from a traditional Chinese herb Isodon eriocalyx, has been shown to possess multifunctional activities such as anti-cancer and anti-inflammatory. However, the function and mechanism of the compound in adipocyte differentiation is still unknown. Here we reported that eriocalyxin B blunted adipogenesis remarkably by inhibiting the accumulation of lipid droplets, triglycerides and the expressions of adipogenesis-related factors, including C/EBPß, C/EBPα, PPARγ, and FABP4. Moreover, we showed that the inhibition might be the consequence of cell cycle being arrested at the G2/M phase during the mitotic clonal expansion of adipocyte differentiation, most likely by suppressing mRNAs and proteins of CDK1, CDK2, Cyclin A and Cyclin B1. Overall, we conclude that eriocalyxin B is capable of inhibiting adipocyte differentiation at the early stage through downregulating the proteins involved in cell cycle progression.
ABSTRACT
Hypoglycemic drugs such as metformin increase glucose uptake and utilization by peripheral tissues to maintain glucose homeostasis, and the AMP-activated protein kinase (AMPK) signaling pathway is an important component of this pharmacological activity. Liver kinase B1 (LKB1) acts as a kinase upstream of AMPK and plays an important regulatory role in glucose metabolism. In recent years, as a tumor suppressor, LKB1's antitumor activity has been widely studied, yet its hypoglycemic activity is not clear. Here, using biochemical and cell viability assays, site-directed mutagenesis, immunoblotting, and immunofluorescence staining, we found that a natural product, antroalbol H isolated from the basidiomycete mushroom Antrodiella albocinnamomea, increases cellular glucose uptake in murine L6 myotubes and 3T3-L1 adipocytes. Of note, our results indicated that this effect is related to LKB1-mediated Thr-172 phosphorylation of AMPKα. Furthermore, we observed that antroalbol H induces the phosphorylation of LKB1 specifically at Thr-189 and changes subcellular localization of LKB1. Finally, antroalbol H treatment strikingly promoted glucose transporter type 4 (GLUT4) translocation to the plasma membrane. We conclude that antroalbol H promotes Thr-189 phosphorylation of LKB1, leading to AMPK activation, revealing this residue as a potential target for increasing glucose uptake, and that antroalbol H therefore has potential for managing hyperglycemia.