Magnolol, a compound extracted from Magnolia officinalis, demonstrates potential efficacy in addressing metabolic dysfunction and cardiovascular diseases. Its biological activities encompass anti-inflammatory, antioxidant, anticoagulant, and anti-diabetic effects. Growth/differentiation factor-15 (GDF-15), a member of the transforming growth factor β superfamily, is considered a potential therapeutic target for metabolic disorders. This study investigated the impact of magnolol on GDF-15 production and its underlying mechanism. The research examined the pharmacological effect of magnolol on GDF-15 expression in vitro and in vivo, and determined the involvement of endoplasmic reticulum (ER) stress signaling in this process. Luciferase reporter assays, chromatin immunoprecipitation, and in vitro DNA binding assays were employed to examine the regulation of GDF-15 by activating transcription factor 4 (ATF4), CCAAT enhancer binding protein γ (CEBPG), and CCCTC-binding factor (CTCF). The study also investigated the effect of magnolol and ATF4 on the activity of a putative enhancer located in the intron of the GDF-15 gene, as well as the influence of single nucleotide polymorphisms (SNPs) on magnolol and ATF4-induced transcription activity. Results demonstrated that magnolol triggers GDF-15 production in endothelial cells (ECs), hepatoma cell line G2 (HepG2) and hepatoma cell line 3B (Hep3B) cell lines, and primary mouse hepatocytes. The cooperative binding of ATF4 and CEBPG upstream of the GDF-15 gene or the E1944285 enhancer located in the intron led to full-power transcription of the GDF-15 gene. SNP alleles were found to impact the magnolol and ATF4-induced transcription activity of GDF-15. In high-fat diet ApoE^-/- mice, administration of magnolol induced GDF-15 production and partially suppressed appetite through GDF-15. These findings suggest that magnolol regulates GDF-15 expression through priming of promoter and enhancer activity, indicating its potential as a drug for the treatment of metabolic disorders.
Lignans/pharmacology* ; Growth Differentiation Factor 15/metabolism* ; Animals ; Biphenyl Compounds/pharmacology* ; Endoplasmic Reticulum Stress/drug effects* ; Activating Transcription Factor 4/genetics* ; Mice ; Humans ; Male ; Magnolia/chemistry* ; CCAAT-Enhancer-Binding Proteins/genetics* ; Mice, Inbred C57BL

The aim of this study was to investigate the effect of activating transcription factor 3 (ATF3) on the differentiation of intramuscular preadipocytes in goat, and to elucidate its possible action pathway at the molecular level. In this study, the recombinant plasmid of goat pEGFP-N1-ATF3 was constructed, and the intramuscular preadipocytes were transfected with liposomes. The relative expression levels of adipocyte differentiation marker genes were detected by quantitative real-time PCR (qRT-PCR). After transfection of goat intramuscular preadipocytes with the goat pEGFP-N1-ATF3 overexpression vector, it was found that the accumulation of lipid droplets was inhibited, and the adipocyte differentiation markers PPARγ, C/EBPα and SREBP1 were extremely significantly down-regulated (P < 0.01), while C/EBPβ and AP2 were significantly down-regulated (P < 0.05). The ATF3 binding sites were predicted to exist in the promoter regions of PPARγ, C/EBPα and AP2 by the ALGGEN PROMO program. The overexpression of goat ATF3 inhibits the accumulation of lipid droplets in intramuscular preadipocytes, and this effect may be achieved by down-regulating PPARγ, C/EBPα and AP2. These results may facilitate elucidation of the regulatory mechanism of ATF3 in regulating the differentiation of goat intramuscular preadipocytes.
3T3-L1 Cells ; Activating Transcription Factor 3/pharmacology* ; Adipocytes ; Adipogenesis/genetics* ; Animals ; CCAAT-Enhancer-Binding Protein-alpha/pharmacology* ; Cell Differentiation ; Goats ; Mice ; PPAR gamma/metabolism*

OBJECTIVES: Endoplasmic reticulum (ER) stress is known to be associated with inflammatory airway diseases, and three major transmembrane receptors: double-stranded RNA-activated protein kinase-like ER kinase, inositol requiring enzyme 1, and activating transcription factor 6 (ATF6) play important roles in ER stress-related proinflammatory signaling. However, the effects of ER stress and these three major signaling pathways on the regulation of the production of airway mucins in human nasal airway epithelial cells have not been elucidated. METHODS: In primary human nasal epithelial cells, the effect of tunicamycin (an ER stress inducer) and 4-phenylbutyric acid (4-PBA, ER stress inhibitor) on the expression of MUC5AC and MUC5B was investigated by reverse transcriptasepolymerase chain reaction, real-time polymerase chain reaction, enzyme immunoassay, and immunoblot analysis. Small interfering RNA (siRNA) transfection was used to identify the mechanisms involved. RESULTS: Tunicamycin increased the expressions of MUC5AC and MUC5B and the mRNA expressions of ER stress-related signaling molecules, including spliced X-box binding protein 1 (XBP-1), transcription factor CCAAT-enhancer-binding protein homologous protein (CHOP), and ATF6. In addition, 4-PBA attenuated the tunicamycin-induced expressions of MUC5AC and MUC5B and the mRNA expressions of ER stress-related signaling molecules. Furthermore, siRNA knockdowns of XBP-1, CHOP, and ATF6 blocked the tunicamycin-induced mRNA expressions and glycoprotein productions of MUC5AC and MUC5B. CONCLUSION.: These results demonstrate that ER stress plays an important role in the regulation of MUC5AC and MUC5B via the activations of XBP-1, CHOP, and ATF6 in human nasal airway epithelial cells.
Activating Transcription Factor 6 ; Carrier Proteins ; CCAAT-Enhancer-Binding Proteins ; Endoplasmic Reticulum Stress ; Endoplasmic Reticulum ; Epithelial Cells ; Glycoproteins ; Humans ; Immunoenzyme Techniques ; Inositol ; Mucins ; Phosphotransferases ; Real-Time Polymerase Chain Reaction ; RNA, Messenger ; RNA, Small Interfering ; Transcription Factor CHOP ; Transcription Factors ; Transfection ; Tunicamycin

A few clues about correlation between endoplasmic reticulum (ER) stress and mulberry (Morus alba) leaves were investigated in only the experimental autoimmune myocarditis and streptozotocin-induced diabetes. To investigate whether a novel extract of mulberry leaves fermented with Cordyceps militaris (EMfC) could suppress ER in fatty liver, alterations in the key parameters for ER stress response were measured in high fat diet (HFD)-induced obese C57L/6 mice treated with EMfC for 12 weeks. The area of adipocytes in the liver section were significantly decreased in the HFD+EMfC treated group as compared to the HFD+Vehicle treated group, while their level was higher in HFD+Vehicle treated group than No treated group. The level of the eukaryotic initiation factor 2 alpha (eIF2α) and inositol-requiring enzyme 1 beta (IRE1α) phosphorylation and CCAAT-enhancer-binding protein homologous protein (CHOP) expression were remarkably enhanced in the HFD+Vehicle treated group. However, their levels were restored in the HFD+EMfC treated group, although some differences were detected in the decrease rate. Similar recovery was observed on the ER stress-induced apoptosis. The level of Caspase-3, Bcl-2 and Bax were decreased in the HFD+EMfC and HFD+orlistat (OT) treated group compared to the HFD+Vehicle treated group. The results of the present study therefore provide first evidence that EMfC with the anti-obesity effects can be suppressed ER stress and ER stress-induced apoptosis in the hepatic steatosis of HFD-induced obesity model.
Adipocytes ; Animals ; Apoptosis ; Caspase 3 ; CCAAT-Enhancer-Binding Proteins ; Cordyceps* ; Diet, High-Fat ; Endoplasmic Reticulum Stress* ; Endoplasmic Reticulum* ; Eukaryotic Initiation Factor-2 ; Fatty Liver ; Liver ; Mice* ; Morus* ; Myocarditis ; Obesity ; Phosphorylation

BACKGROUND: Behçet disease (BD) is a relapsing inflammatory disease with increased production of inflammatory cytokines in peripheral blood mononuclear cells (PBMCs); however, the underlying molecular mechanisms are not well known. OBJECTIVE: To analyze whether the differential expression of transcription factors is involved in the increased tumor necrosis factor (TNF)-α and interleukin (IL)-6 production by PBMCs of BD patients compared to healthy controls (HCs). METHODS: Expression of transcription factors was examined by real-time reverse transcriptase-polymerase chain reaction and western blotting. Cytokine production by CD11b+ cells transfected with siRNAs against transcription factors was measured by enzyme-linked immunosorbent assay. RESULTS: In the absence of lipopolysaccharide stimulation, the transcript level of CCAAT-enhancer-binding proteins (C/EBP) β was increased in PBMCs from patients with active BD compared to that in PBMCs from patients with stable BD. The C/EBPδ transcript level was higher in PBMCs from patients with active BD than in those from HCs. The activating transcription factor 3 (ATF3) transcript level was increased in PBMCs from patients with stable BD compared to that in PBMCs from HCs. siRNAs targeting C/EBPβ and C/EBPδ significantly reduced the production of IL-6 and TNF-α in lipopolysaccharide-stimulated CD11b+ cells from patients with BD as well as from HCs. CONCLUSION: We found differential expression of C/EBPβ, C/EBPδ, and ATF3 in PBMCs from patients with BD depending on disease activity, indicating the involvement of these molecules in BD pathogenesis.
Activating Transcription Factor 3 ; Behcet Syndrome* ; Blotting, Western ; CCAAT-Enhancer-Binding Proteins ; Cytokines ; Enzyme-Linked Immunosorbent Assay ; Gene Expression ; Humans ; Interleukin-6 ; Interleukins ; RNA, Small Interfering ; Transcription Factors* ; Tumor Necrosis Factor-alpha

OBJECTIVETo investigate the expressions of inflammation- and fibrosis-related genes in perinephric and subcutaneous adipose tissues in patients with adrenocorticotropic hormone (ACTH)-independent Cushing's syndrome.

METHODSThe perinephric and subcutaneous adipose tissues adipose tissues were obtained from 8 patients with ACTH-independent Cushing's syndrome undergoing laparoscopic retroperitoneal adrenalectomy. Real-time PCR was used to detect the mRNA expression levels of interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α), matrix metallopeptidase 2 (MMP-2), TIMP metallopeptidase inhibitor 1 (TIMP-1), early growth response 1 (EGR1), CCAAT/enhancer binding protein β(CEBPβ), uncoupling protein 1(UCP-1), PPARγ coactivator 1 alpha (PGC1α) and cell death-inducing DFFA-like effector a (CIDEA).

RESULTSThe mRNA level of CIDEA was significantly higher in the perinephric adipose tissue (peri-N) than in the subcutaneous adipose tissue (subQ) (P<0.05). The expressions of CEBPβ, UCP-1, and PGC1α mRNA in the peri-N were similar with those in the subQ. The expressions of IL-6, TIMP1 and EGR1 mRNA in the subQ were significantly higher than those in the peri-N (P<0.05). No significant difference in TNF-α and MMP-2 mRNA levels was found between peri-N and subQ.

CONCLUSIONThe expression levels of the inflammation- and fibrosis-related genes are higher in the subQ than in the peri-N of patients with ACTH-independent Cushing's syndrome, suggesting that chronic exposure to endogenous hypercortisolism may cause adipose tissue dysfunction.

Adrenalectomy ; Adrenocorticotropic Hormone ; CCAAT-Enhancer-Binding Protein-beta ; metabolism ; Cushing Syndrome ; metabolism ; surgery ; Early Growth Response Protein 1 ; metabolism ; Humans ; Matrix Metalloproteinase 2 ; metabolism ; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ; metabolism ; Real-Time Polymerase Chain Reaction ; Subcutaneous Fat ; metabolism ; Tissue Inhibitor of Metalloproteinase-1 ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism ; Uncoupling Protein 1 ; metabolism

BACKGROUND: The aim of this study was an in vitro investigation of the effect of high glucose concentration on adipogenesis, as prolonged hyperglycemia alters adipocyte differentiation. METHODS: 3T3-L1 preadipocytes differentiated in the presence of varying concentrations of glucose (25, 45, 65, 85, and 105 mM) were assessed for adipogenesis using AdipoRed (Lonza) assay. Cell viability and proliferation were measured using MTT reduction and [3H] thymidine incorporation assay. The extent of glucose uptake and glycogen synthesis were measured using radiolabelled 2-deoxy-D-[1-3H] glucose and [14C]-UDP-glucose. The gene level expression was evaluated using reverse transcription-polymerase chain reaction and protein expression was studied using Western blot analysis. RESULTS: Glucose at 105 mM concentration was observed to inhibit adipogenesis through inhibition of CCAAT-enhancer-binding proteins, sterol regulatory element-binding protein, peroxisome proliferator-activated receptor and adiponectin. High concentration of glucose induced stress by increasing levels of toll-like receptor 4, nuclear factor kappaB and tumor necrosis factor alpha thereby generating activated preadipocytes. These cells entered the state of hyperplasia through inhibition of p27 and proliferation was found to increase through activation of protein kinase B via phosphoinositide 3 kinase dependent pathway. This condition inhibited insulin signaling through decrease in insulin receptor beta. Although the glucose transporter 4 (GLUT4) protein remained unaltered with the glycogen synthesis inhibited, the cells were found to exhibit an increase in glucose uptake via GLUT1. CONCLUSION: Adipogenesis in the presence of 105 mM glucose leads to an uncontrolled proliferation of activated preadipocytes providing an insight towards understanding obesity.
Adipocytes ; Adipogenesis ; Adiponectin ; Blotting, Western ; CCAAT-Enhancer-Binding Proteins ; Cell Survival ; Glucose ; Glucose Transport Proteins, Facilitative ; Glycogen ; Hyperglycemia ; Hyperplasia ; Insulin ; Obesity ; Peroxisomes ; Phosphotransferases ; Proto-Oncogene Proteins c-akt ; Receptor, Insulin ; Thymidine ; Toll-Like Receptor 4 ; Tumor Necrosis Factor-alpha

OBJECTIVETo investigate the effect of a common polymorphism rs928508(A/G) in flanking region of miR-30c on the expression of pri, pre and mature miR-30c, and discuss the effect of this polymorphism on the maturing process of miR-30c in lung carcinoma.

METHODSThe pGL3-promoter-miR-30c-A and pGL3-promoter-miR-30c-G luciferase plasmids were created containing A or G allele of miR-30c flanking region. Taqman assay was used to genotype rs928508 polymorphism in 50 lung cancer tissues. RT-PCR was performed to determine the expression of pri-miR-30c, pre-miR-30c, mature miR-30c and miR-30c host gene NFYC in the 50 lung cancer tissues.

RESULTSThe luciferase expression level of the pGL3-promoter-miR-30c-A construct group was not significantly different compared with that in the the pGL3-promoter-miR-30c-G construct group (A549 cells, P = 0.758; 293A cells, P = 0.554; CHO cells, P = 0.175). The results demonstrated that rs928508(A/G) variant had no effect on the transcriptional regulation of pri-miR-30c. In the genotype-phenotype collection analysis of the 50 lung cancer tissues, the expression of pre-miR-30c and mature miR-30c for rs928508 AG/GG genotypes showed significantly lower levels compared with those in the AA genotype (P = 0.009, P = 0.011). However, the expression of pri-miR-30c showed no significant difference between AG/GG genotypes and AA genotype. Similarly, the expression of host NFYC gene was correlated with pri-miR-30c, showed no significant difference between AG/GG genotypes and AA genotype.

CONCLUSIONThe rs928508(A/G) polymorphism in flanking region of miR-30c could influence the processing from pri-miR-30c to mature miR-30c, but does not influence the transcription of pri-miR-30c.

Animals ; CCAAT-Binding Factor ; genetics ; metabolism ; CHO Cells ; Cell Line, Tumor ; Cricetinae ; Genotype ; HEK293 Cells ; Humans ; Lung Neoplasms ; genetics ; metabolism ; pathology ; MicroRNAs ; genetics ; metabolism ; Polymorphism, Single Nucleotide ; Promoter Regions, Genetic

To investigate the molecular mechanisms of all-trans retinoic acid (ATRA)-induced rig-g gene expression and to better understand the signal transduction of ATRA during acute promyelocytic leukemia (APL) cell differentiation, the luciferase reporter assay, co-immunoprecipitation and chromatin immunoprecipitation were used to clarify the basic transcriptional factors, which directly initiated the expression of rig-g gene. The results showed that the expression of STAT2, IRF-9 and IRF-1 could be upregulated by ATRA with different kinetics in NB4 cells. IRF-9 was able to interact with STAT2 to form a complex, which could bind the rig-g gene promoter and trigger the rig-g expression. IRF-1 alone could also activate the reporter gene containing rig-g gene promoter, but C/EBPalpha could strongly inhibit this transcription activity of IRF-1. It is concluded that during ATRA-induced APL cell differentiation, IRF-1 is first upregulated by ATRA, and then IRF-1 increases the protein levels of IRF-9 and STAT2 with the downregulation of C/EBPalpha. The complex of IRF-9 and STAT2 is the primary transcriptional factor for rig-g gene induction. This study will be helpful for better understanding the signal transduction networks of ATRA during the course of APL cell differentiation.
CCAAT-Enhancer-Binding Protein-alpha ; metabolism ; Gene Expression Regulation, Leukemic ; drug effects ; Genes, Regulator ; drug effects ; Humans ; Interferon Regulatory Factor-1 ; metabolism ; Interferon-Stimulated Gene Factor 3, gamma Subunit ; metabolism ; Intracellular Signaling Peptides and Proteins ; genetics ; Leukemia, Promyelocytic, Acute ; genetics ; STAT2 Transcription Factor ; metabolism ; Signal Transduction ; Tretinoin ; pharmacology ; Tumor Cells, Cultured

As a member of the hox gene family, hoxB4 gene encodes a class of DNA-dependent homeobox domain nucleoprotein, which is a specific transcription factor, playing an important role in regulating the balance between self-renewal and differentiation of hematopoietic stem cells (HSCs). Therefore, it is important to understand the mechanisms involved in regulating expression of hoxB4 in the HSC. Previous studies have suggested that some hoxB4 upstream regulatory factors, such as USF-1 (upstream activating factor -1), USF-2 (upstream activating factor -2) and NF-Y complex, as well as hematopoietic cytokines, such as platelet growth factor (TPO) and Wnt3a protein, play important regulatory roles in the expression of hoxB4 in hematopoietic stem cells. In this review the structure and biological characteristics of hoxB4, mechanisms involved in regulating expression of hoxB4 in the HSC are summarized.
CCAAT-Binding Factor ; metabolism ; Gene Expression Regulation ; Genes, Homeobox ; genetics ; physiology ; Hematopoietic Stem Cells ; metabolism ; Homeodomain Proteins ; genetics ; metabolism ; physiology ; Humans ; Transcription Factors ; genetics ; metabolism ; physiology ; Upstream Stimulatory Factors ; metabolism ; Wnt Proteins ; metabolism ; Wnt3 Protein ; Wnt3A Protein