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

Treating patients with esophageal squamous cell carcinoma (ESCC) is challenging due to the high chemoresistance. Growth differentiation factor 15 (GDF15) is crucial in the development of various types of tumors and negatively related to the prognosis of ESCC patients according to our previous research. In this study, the link between GDF15 and chemotherapy resistance in ESCC was further explored. The relationship between GDF15 and the chemotherapy response was investigated through in vitro and in vivo studies. ESCC patients with high levels of GDF15 expression showed an inferior chemotherapeutic response. GDF15 improved the tolerance of ESCC cell lines to low-dose cisplatin by regulating AKT phosphorylation via TGFBR2. Through an in vivo study, we further validated that the anti-GDF15 antibody improved the tumor inhibition effect of cisplatin. Metabolomics showed that GDF15 could alter cellular metabolism and enhance the expression of UGT1A. AKT and TGFBR2 inhibition resulted in the reversal of the GDF15-induced expression of UGT1A, indicating that TGFBR2-AKT pathway-dependent metabolic pathways were involved in the resistance of ESCC cells to cisplatin. The present investigation suggests that a high level of GDF15 expression leads to ESCC chemoresistance and that GDF15 can be targeted during chemotherapy, resulting in beneficial therapeutic outcomes.
Humans ; Esophageal Squamous Cell Carcinoma/drug therapy* ; Cisplatin/metabolism* ; Esophageal Neoplasms/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; Carcinoma, Squamous Cell/genetics* ; Growth Differentiation Factor 15/therapeutic use* ; Receptor, Transforming Growth Factor-beta Type II/therapeutic use* ; Cell Line, Tumor ; Cell Proliferation ; Gene Expression Regulation, Neoplastic

Growth differentiation factor 15 (GDF-15) is a member of the transforming growth factor-β superfamily. It is widely distributed in the central and peripheral nervous systems. Whether and how GDF-15 modulates nociceptive signaling remains unclear. Behaviorally, we found that peripheral GDF-15 significantly elevated nociceptive response thresholds to mechanical and thermal stimuli in naïve and arthritic rats. Electrophysiologically, we demonstrated that GDF-15 decreased the excitability of small-diameter dorsal root ganglia (DRG) neurons. Furthermore, GDF-15 concentration-dependently suppressed tetrodotoxin-resistant sodium channel Nav1.8 currents, and shifted the steady-state inactivation curves of Nav1.8 in a hyperpolarizing direction. GDF-15 also reduced window currents and slowed down the recovery rate of Nav1.8 channels, suggesting that GDF-15 accelerated inactivation and slowed recovery of the channel. Immunohistochemistry results showed that activin receptor-like kinase-2 (ALK2) was widely expressed in DRG medium- and small-diameter neurons, and some of them were Nav1.8-positive. Blockade of ALK2 prevented the GDF-15-induced inhibition of Nav1.8 currents and nociceptive behaviors. Inhibition of PKA and ERK, but not PKC, blocked the inhibitory effect of GDF-15 on Nav1.8 currents. These results suggest a functional link between GDF-15 and Nav1.8 in DRG neurons via ALK2 receptors and PKA associated with MEK/ERK, which mediate the peripheral analgesia of GDF-15.
Analgesia ; Animals ; Ganglia, Spinal ; Growth Differentiation Factor 15 ; NAV1.8 Voltage-Gated Sodium Channel ; Rats ; Sensory Receptor Cells ; Sodium Channels ; Tetrodotoxin/pharmacology*

Obesity results in an inflammatory microenvironment in adipose tissue, leading to the deterioration of tissue protective mechanisms. Although recent studies suggested the importance of type 2 immunity in an anti-inflammatory microenvironment in adipose tissue, the regulatory effects of T helper 2 (Th2) cytokines on systemic metabolic regulation are not fully understood. Recently, we identified the roles of the Th2 cytokine (interleukin 4 [IL-4] and IL-13)-induced adipokine, growth differentiation factor 15 (GDF15), in adipose tissue in regulating systemic glucose metabolism via signal transducer and activator of transcription 6 (STAT6) activation. Moreover, we showed that mitochondrial oxidative phosphorylation is required to maintain these macrophage-regulating autocrine and paracrine signaling pathways via Th2 cytokine-induced secretion of GDF15. In this review, we discuss how the type 2 immune response and Th2 cytokines regulate metabolism in adipose tissue. Specifically, we review the systemic regulatory roles of Th2 cytokines in metabolic disease and the role of mitochondria in maintenance of type 2 responses in adipose tissue homeostasis.
Adipokines ; Adipose Tissue ; Cytokines ; Glucose ; Growth Differentiation Factor 15 ; Homeostasis ; Metabolic Diseases ; Metabolism ; Mitochondria ; Obesity ; Oxidative Phosphorylation ; Paracrine Communication ; STAT6 Transcription Factor

Immunosuppressive regulatory T lymphocytes (Treg) expressing the transcription factor Foxp3 play a vital role in the maintenance of tolerance of the immune-system to self and innocuous non-self. Most Treg that are critical for the maintenance of tolerance to self, develop as an independent T-cell lineage from common T cell precursors in the thymus. In this organ, their differentiation requires signals from the T cell receptor for antigen, from co-stimulatory molecules, as well as from cytokine-receptors. Here we focus on the cytokines implicated in thymic development of Treg, with a particular emphasis on the roles of interleukin-2 (IL-2) and IL-15. The more recently appreciated involvement of TGF-β in thymic Treg development is also briefly discussed. Finally, we discuss how cytokine-dependence of Treg development allows for temporal, quantitative, and potentially qualitative modulation of this process.
Animals ; Cell Differentiation ; genetics ; Cytokines ; immunology ; Forkhead Transcription Factors ; genetics ; immunology ; Gene Expression Regulation ; Immune Tolerance ; genetics ; Interleukin-15 ; genetics ; immunology ; Interleukin-2 ; genetics ; immunology ; Mice ; Receptors, Antigen, T-Cell ; genetics ; immunology ; T-Lymphocytes, Regulatory ; immunology ; Transforming Growth Factor beta ; genetics ; immunology

Growth differentiation factor-15 (GDF-15) is a member of the transforming growth factor beta superfamily. GDF-15 expression is dramatically upregulated during acute brain injury, cancer, cardiovascular disease, and inflammation, suggesting its potential value as a disease biomarker. It has been suggested that GDF-15 has neurotropic effects in the nervous system. Our studies showed that GDF-15 modulated the expression of neuronal Kand Caion channels and increased the release of excitatory transmitter in the medial prefrontal cortex of mice. GDF-15 is also involved in the complex modulation of cancer and cardiovascular disease. Here, we reviewed studies involving the modulation of GDF-15 expression and its mechanisms, the primary pathological and physiological functions of GDF-15 in neurological and cardiovascular systems, and its role in cancer progression. The biological effects and the values of GDF-15 in basic research and clinical applications were also addressed.
Animals ; Brain Injuries ; physiopathology ; Calcium Channels ; metabolism ; Cardiovascular Diseases ; physiopathology ; Disease Progression ; Growth Differentiation Factor 15 ; metabolism ; Humans ; Inflammation ; Mice ; Neoplasms ; physiopathology ; Nervous System ; metabolism ; Potassium Channels ; metabolism ; Prefrontal Cortex ; metabolism ; Transforming Growth Factor beta ; Up-Regulation

BACKGROUND/AIMS: Growth differentiation factor 15 (GDF-15) belongs to the transforming growth factor-β superfamily. GDF-15 is emerging as a biomarker for several diseases. The aim of this study was to determine the clinical performances of GDF-15 for the prediction of liver fibrosis and severity in chronic liver disease. METHODS: The serum GDF-15 levels were examined via enzyme immunoassay in 145 patients with chronic liver disease and 101 healthy individuals. The patients with chronic liver disease consisted of 54 patients with chronic hepatitis, 44 patients with compensated liver cirrhosis, and 47 patients with decompensated liver cirrhosis. RESULTS: Of the patients with chronic liver diseases, the decompensated liver cirrhosis patients had an increased serum GDF-15 (3,483 ng/L) level compared with the patients with compensated liver cirrhosis (1,861 ng/L) and chronic hepatitis (1,232 ng/L). The overall diagnostic accuracies of GDF-15, as determined by the area under the receiver operating characteristic curves, were as follows: chronic hepatitis=0.656 (>574 ng/L, sensitivity, 53.7%; specificity, 79.2%), compensated liver cirrhosis=0.886 (>760 ng/L, sensitivity, 75.6%; specificity, 92.1%), and decompensated liver cirrhosis=0.984 (>869 ng/L, sensitivity, 97.9%; specificity, 94.1%). CONCLUSIONS: This investigation represents the first study to demonstrate the availability of GDF-15 in chronic liver disease. GDF-15 comprised a useful biomarker for the prediction of liver fibrosis and severity in chronic liver disease.
Biomarkers ; Fibrosis ; Growth Differentiation Factor 15* ; Hepatitis, Chronic ; Humans ; Immunoenzyme Techniques ; Liver Cirrhosis ; Liver Diseases* ; Liver* ; ROC Curve ; Sensitivity and Specificity

We investigated an association between serum Growth Differentiation Factor 15 (GDF15) level and cardiovascular risk in patients with newly diagnosed type 2 diabetes mellitus (T2D). A total of 107 participants were screened for T2D and divided into a T2D group and a control group (without diabetes). We used the Framingham risk score (FRS) and the New Pooled Cohort Equation score to estimate the 10-year risk of atherosclerotic cardiovascular disease. Serum GDF15 levels were measured using an enzyme-linked immunosorbent assay. Correlation analyses were performed to evaluate the associations between GDF15 level and cardiovascular risk scores. The mean serum GDF15 level was elevated in the T2D group compared to the control group (P < 0.001). A positive correlation was evident between serum GDF15 level and age (r = 0.418, P = 0.001), the FRS (r = 0.457, P < 0.001), and the Pooled Cohort Equation score (r = 0.539, P < 0.001). After adjusting for age, LDL-C level, and body mass index (BMI), the serum GDF15 level was positively correlated with the FRS and the New Pooled Cohort Equation score. The serum GDF15 level is independently associated with cardiovascular risk scores of newly diagnosed T2D patients. This suggests that the level of GDF15 may be a useful predictive biomarker of cardiovascular risk in newly diagnosed T2D patients.
Body Mass Index ; Cardiovascular Diseases ; Cohort Studies ; Diabetes Mellitus, Type 2* ; Enzyme-Linked Immunosorbent Assay ; Growth Differentiation Factor 15* ; Humans

BACKGROUNDIncreased level of serum macrophage inhibitory cytokine-1 (MIC-1), a member of transforming growth factor-μ superfamily, was found in patients with epithelial tumors. This study aimed to evaluate whether serum level of MIC-1 can be a candidate diagnostic and prognostic indicator for early-stage nonsmall cell lung cancer (NSCLC).

METHODSA prospective study enrolled 152 patients with Stage I-II NSCLC, who were followed up after surgical resection. Forty-eight patients with benign pulmonary disease (BPD) and 105 healthy controls were also included in the study. Serum MIC-1 levels were measured using an enzyme-linked immunosorbent assay, and the association with clinical and prognostic features was analyzed.

RESULTSIn patients with NSCLC, serum protein levels of MIC-1 were significantly increased compared with healthy controls and BPD patients (all P< 0.001). A threshold of 1000 pg/ml of MIC-1 was found in patients with early-stage (Stage I and II) NSCLC, with sensitivity and specificity of 70.4% and 99.0%, respectively. The serum levels of MIC-1 were associated with age (P = 0.001), gender (P = 0.030), and T stage (P = 0.022). Serum MIC-1 threshold of 1465 pg/ml was found in patients with poor early outcome, with sensitivity and specificity of 72.2% and 66.1%, respectively. The overall 3-year survival rate of NSCLC patients with high serum levels of MIC-1 (≥1465 pg/ml) was lower than that of NSCLC patients with low serum MIC-1 levels (77.6% vs. 94.8%). Multivariate Cox regression survival analysis showed that a high serum level of MIC-1 was an independent risk factor for reduced overall survival (hazard ratio = 3.37, 95% confidential interval: 1.09-10.42, P= 0.035).

CONCLUSIONThe present study suggested that serum MIC-1 may be a potential diagnostic and prognostic biomarker for patients with early-stage NSCLC.

Adult ; Aged ; Carcinoma, Non-Small-Cell Lung ; blood ; mortality ; pathology ; surgery ; Enzyme-Linked Immunosorbent Assay ; Female ; Growth Differentiation Factor 15 ; blood ; Humans ; Male ; Middle Aged ; Neoplasm Staging ; Prognosis ; Proportional Hazards Models ; Prospective Studies ; Survival Rate

BACKGROUND: Elevated serum levels of growth differentiation factor-15 (GDF-15) are associated with type 2 diabetes. Therefore, the effects of atorvastatin on metabolic parameters and GDF-15 levels in patients with type 2 diabetes and dyslipidemia were evaluated. METHODS: In this prospective randomized trial from February 2013 to March 2014, 50 consecutive type 2 diabetic patients with a low density lipoprotein cholesterol (LDL-C) levels > or =100 mg/dL were enrolled. The patients were divided into two groups based on the amount of atorvastatin prescribed, 10 mg/day (n=23) or 40 mg/day (n=27). The effect of atorvastatin on metabolic parameters, including lipid profiles and GDF-15 levels, at baseline and after 8 weeks of treatment were compared. RESULTS: The baseline metabolic parameters and GDF-15 levels were not significantly different between the two groups. After 8 weeks of treatment, the total cholesterol (TC) and LDL-C levels were significantly decreased in both groups. The mean changes in TC and LDL-C levels were more significant in the 40 mg atorvastatin group. The GDF-15 level was decreased in the 10 mg atorvastatin group, from 1,460.6+/-874.8 to 1,451.0+/-770.8 pg/mL, and was increased in the 40 mg atorvastatin group, from 1,271.6+/-801.0 to 1,341.4+/-855.2 pg/mL. However, the change in the GDF-15 level was not statistically significant in the 10 or 40 mg atorvastatin group (P=0.665 and P=0.745, respectively). CONCLUSION: The GDF-15 levels were not significantly changed after an 8-week treatment with atorvastatin in type 2 diabetic patients.
Cholesterol ; Cholesterol, LDL ; Diabetes Mellitus, Type 2* ; Dyslipidemias* ; Growth Differentiation Factor 15 ; Humans ; Prospective Studies ; Atorvastatin Calcium