OBJECTIVE: To determine the effect of metformin and adiponectin on the proliferation of EC cells and the relationship between metformin and adiponectin. METHODS: The proliferation impact of different concentrations of metformin and adiponectin on two types of EC cells ishikawa (IK) and HEC-1B was confirmed by CCK-8 method. qRT-PCR and Western blot were used to detect the effect of different concentrations of metformin on the changes of adiponectin receptors (AdipoR1 and AdipoR2) of the EC cells both in mRNA and protein level and the role of compound C, an adenosine monophosphate-activated protein kinase (AMPK) inhibitor, on the above effects. RESULTS: (1) Both metformin and adiponectin could significantly promote the proliferation of endometrial cancer (EC) cells in a time and concentration dependent manner (P<0.05).(2)Metformin and adiponectin had synergy anti-proliferative effect on EC cells and the combination index (CI) value of IK cells was 0.906 34 and of HEC-1B cells was 0.827 65. (3)qRT-PCR was used to detect the mRNA levels of AdipoR1 and AdipoR2 after 5 mmol/L and 10 mmol/L metformin, respectively, stimulating IK and HEC-1B cells for 48 hours and the mRNA expressions of AdipoR1 and AdipoR2 were significantly increased when compared with the control group (0 mmol/L)(IK: AdipoR1 of 5 mmol/L and 10 mmol/L group: P<0.001,AdipoR2 of 5 mmol/L group: P<0.001; HEC-1B: AdipoR1 of 5 mmol/L group: P<0.001, 10 mmol/L group: P=0.023, AdipoR2 of 5 mmol/L group: P<0.001, 10 mmol/L group: P=0.024). When combined with compound C, the RNA levels of AdipoR1 and AdipoR2 were not different compared with the control group (0 mmol/L, P>0.05). (4) Western blot was used to detect the protein levels of AdipoR1 and AdipoR2 after 5 mmol/L and 10 mmol/L metformin, stimulating IK and HEC-1B cells for 48 hours and the protein level was significantly increased when compared with the control group (0 mmol/L)(IK: AdipoR1 of 5 mmol/L group: P=0.04, 10 mmol/L group: P=0.033, AdipoR2 of 5 mmol/L group: P=0.044, 10 mmol/L group: P=0.046; HEC-1B: AdipoR1 of 5 mmol/L group: P=0.04, 10 mmol/L group: P=0.049, AdipoR2 of 5 mmol/L group: P=0.043, 10 mmol/L group: P=0.035). When combined with compound C,the protein levels of AdipoR1 and AdipoR2 were not different compared with the control group (0 mmol/L, P>0.05). CONCLUSION We find that metformin and adiponectin have synergy anti-proliferative effect on EC cells. Besides, metformin can increase adiponectin receptors expressions of EC cells both in mRNA and protein levels and this effect is accomplished by the activation of AMPK signaling pathway.
Adiponectin/physiology* ; Cell Proliferation/drug effects* ; Endometrial Neoplasms/pathology* ; Female ; Humans ; Hypoglycemic Agents/pharmacology* ; Metformin/pharmacology* ; Receptors, Adiponectin ; Signal Transduction

OBJECTIVETo investigate the effects of GW4064, a farnesoid X receptor (FXR) agonist, on adiponectin and its receptors during the differentiation of 3T3-L1 preadipocytes and on adiponectin receptors in HepG2 cells.

METHODSThe mRNA expressions of FXR, PPARγ2, adiponectin, AdipoR1, and AdipoR2 and the protein levels of adiponectin on days 0, 2, 4, 6, and 8 during the differentiation of 3T3-L1 preadipocytes treated with GW4064 were detected by fluorescent real-time PCR and ELISA, respectively. The mRNA expressions of AdipoR1 and AdipoR2 in HepG2 cells were also examined at 0, 12, 24, and 48 h after GW4064 treatment.

RESULTSThe mRNA expressions of FXR, PPARγ2, adiponectin, and AdipoR2 in 3T3-L1 preadipocytes and AdipoR2 in HepG2 cells treated with GW4064 was significantly increased compared with the control group (all P<0.05). The protein level of adiponectin was also significantly increased after GW4064 treatment. The expression of AdipoR1 in either 3T3-L1 preadipocytes or HepG2 cells showed no significant changes after GW4064 treatment.

CONCLUSIONGW4064 can up-regulate the expressions of FXR, PPARγ2, adiponectin, AdipoR2 in 3T3-L1 preadipocytes and AdipoR2 in HepG2 cells. As adiponectin and its receptors are two important factors in the treatment of non-alcoholic fatty liver disease, FXR agonist may potentially produce therapeutic effect on non-alcoholic fatty liver disease and can regulate adipocytes via up-regulating PPARγ during adipocyte differentiation.

3T3-L1 Cells ; Adiponectin ; metabolism ; Animals ; Cell Differentiation ; drug effects ; Hep G2 Cells ; Humans ; Isoxazoles ; pharmacology ; Mice ; PPAR gamma ; metabolism ; Receptors, Adiponectin ; metabolism ; Receptors, Cytoplasmic and Nuclear ; agonists

OBJECTIVE: To investigate the effect of adiponectin on the osteoblast differentiation and its signal transduction. METHODS: Adipopnectin receptor (AdipoR) was detected by immunoblot analysis. Alkaline phosphatase (ALP) activity was measured by enzyme-linked immunosorbent assay. Osteocalcin was measured by a specific radioimmunoassay kit, and the extent of mineralized matrix was determined. RNA interference was used to down-regulate the expression of AdipoR1 in human osteoblasts, and the effect of adiponectin on osteoblast differentiation was investigated. RESULTS: Only AdipoR1 protein was detected in human osteoblasts. Adiponectin could promote osteoblast differentiation, and result in a dose-dependent increase in ALP activity, osteocalcin secretion, and an increase in mineralized nodules. Suppression of AdipoR1 with siRNA could abolish the adiponectin induced ALP expression. Adiponectin could induce the activation of p38 and JNK, but not ERK1/2 in osteoblasts, and the pretreatment of osteoblasts with the p38 inhibitor (SB203580) could block the adiponectin-induced ALP activity. CONCLUSION Adiponectin can induce human osteoblast differentiation via AdipoR1/p38 pathway.
Adiponectin ; pharmacology ; Alkaline Phosphatase ; metabolism ; Cell Differentiation ; drug effects ; Cells, Cultured ; Humans ; Osteoblasts ; cytology ; metabolism ; Osteocalcin ; analysis ; RNA, Small Interfering ; genetics ; Receptors, Adiponectin ; biosynthesis ; Signal Transduction

AMP-activated protein kinase (AMPK) is a key enzyme in the regulation of cellular energy homeostasis. Recent studies demonstrated that AMPK also plays an important role in the modulation of inflammation, an energy-intensive molecular response. The commonly used AMPK activators include 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) and A-769662. In addition, the biological activities of metformin and adiponectin are closely related to activation of AMPK. Numerous studies have shown that these AMPK activators play an effectively protective role in animal models of acute lung injury, asthma, colitis, hepatitis, atherosclerosis and other inflammatory diseases. Therefore, AMPK activators may have promising potential for the prevention and treatment of inflammation related diseases.
AMP-Activated Protein Kinases ; physiology ; Adiponectin ; pharmacology ; Aminoimidazole Carboxamide ; pharmacology ; Animals ; Enzyme Activation ; Inflammation ; enzymology ; Metformin ; pharmacology ; Pyrones ; pharmacology ; Thiophenes ; pharmacology

Adiponectin ; blood ; Adolescent ; Adult ; Female ; Hepatitis C, Chronic ; blood ; drug therapy ; Humans ; Interferon-alpha ; pharmacology ; Male ; Middle Aged ; Polyethylene Glycols ; pharmacology ; Recombinant Proteins ; pharmacology ; Ribavirin ; pharmacology ; Young Adult

BACKGROUNDThe synovial fluid concentrations of adiponectin are significantly higher in patients with rheumatoid arthritis (RA) than in patients with osteoarthritis (OA). Accumulating evidence suggests that adiponectin may be an inducer of inflammation in arthritis, but the mechanism remains unclear. The objectives of this study were to compare the expression levels of adiponectin receptors in rheumatoid arthritis synovial fibroblasts (RASF) and osteoarthritis synovial fibroblasts (OASF), evaluate the roles of adiponectin receptors in adiponectin-induced prostaglandin E(2) (PGE(2)) production, and then investigate the effects of a nonsteroidal anti-inflammatory drug (NSAID) and a cyclooxygenase (COX)-2-selective inhibitor on adiponectin-induced PGE(2) release.

METHODSThe expressions of adiponectin receptor 1 (AdipoR1) and AdipoR2 mRNA and protein in synovial fibroblasts from seven patients with RA and eight patients with OA undergoing total knee replacement were evaluated by real-time polymerase chain reaction, immunofluorescence microscopy and Western blotting analysis. Adiponectin-induced PGE(2) production was detected by enzyme-linked immunosorbent assay. RNA interference against the AdipoR1 and AdipoR2 genes was performed to investigate the effects of the adiponectin receptors on adiponectin-induced PGE(2) production in both RASF and OASF.

RESULTSAdipoR1 and AdipoR2 mRNA and protein were expressed by both RASF and OASF. Compared with OASF, RASF exhibited higher levels of AdipoR1, but there was no significant difference for AdipoR2. Adiponectin induced the production of PGE(2) by the synovial fibroblasts in a concentration-dependent manner, and this was more obvious in RASF. RNA interference showed that the difference may be mediated by the diverse distribution of AdipoR1. The adiponectin-induced PGE(2) production was efficiently relieved by the NSAID and COX-2-selective inhibitor.

CONCLUSIONThe present findings suggest that AdipoR1 may mediate the difference in adiponectin-induced PGE(2) production in RASF and OASF.

Adiponectin ; pharmacology ; Arthritis, Rheumatoid ; metabolism ; Blotting, Western ; Cells, Cultured ; Dinoprostone ; metabolism ; Female ; Fibroblasts ; drug effects ; metabolism ; Humans ; Immunoassay ; Male ; Microscopy, Fluorescence ; Middle Aged ; Osteoarthritis ; metabolism ; RNA, Small Interfering ; Real-Time Polymerase Chain Reaction ; Receptors, Adiponectin ; genetics ; metabolism ; Synovial Membrane ; cytology

OBJECTIVE: Depression and metabolic disorders have overlapping psychosocial and pathophysiological causes. Current research is focused on the possible role of adiponectin in regulating common biological mechanisms. Xiaoyao San (XYS), a classic Chinese medicine compound, has been widely used in the treatment of depression and can alleviate metabolic disorders such as lipid or glucose metabolism disorders. However, the ability of XYS to ameliorate depression-like behavior as well as metabolic dysfunction in mice and the underlying mechanisms are unclear. METHODS: An in vivo animal model of depression was established by chronic social defeat stress (CSDS). XYS and fluoxetine were administered by gavage to the drug intervention group. Depression-like behaviors were analyzed by the social interaction test, open field test, forced swim test, and elevated plus maze test. Glucose levels were measured using the oral glucose tolerance test. The involvement of certain molecules was validated by immunofluorescence, histopathology, and Western blotting. In vitro, hypothalamic primary neurons were exposed to high glucose to induce neuronal damage, and the neuroprotective effect of XYS was evaluated by cell counting kit-8 assay. Immunofluorescence and Western blotting were used to evaluate the influences of XYS on adiponectin receptor 1 (AdipoR1), adenosine 5'-monophosphate-activated protein kinase (AMPK), acetyl-coenzyme A carboxylase (ACC) and other related proteins. RESULTS: XYS ameliorated CSDS-induced depression-like behaviors and glucose tolerance impairment in mice and increased the level of serum adiponectin. XYS also restored Nissl bodies in hypothalamic neurons in mice that exhibited depression-like behaviors and decreased the degree of neuronal morphological damage. In vivo and in vitro studies indicated that XYS increased the expression of AdipoR1 in hypothalamic neurons. CONCLUSION Adiponectin may be a key regulator linking depression and metabolic disorders; regulation of the hypothalamic AdipoR1/AMPK/ACC pathway plays an important role in treatment of depression by XYS.
AMP-Activated Protein Kinases/metabolism* ; Acetyl-CoA Carboxylase/metabolism* ; Adiponectin/metabolism* ; Animals ; Antidepressive Agents/pharmacology* ; China ; Depression/drug therapy* ; Disease Models, Animal ; Drugs, Chinese Herbal/therapeutic use* ; Glucose ; Hypothalamus/metabolism* ; Mice ; Receptors, Adiponectin/metabolism*

OBJECTIVETo explore the effects of berberine and insulin on adiponectin mRNA expression in 3T3-L1 adipocyte.

METHODThe 3T3-L1 adipocyte was treated with berberine and insulin for 48 hours, the level of adiponectin mRNA in 3T3-L1 adipocyte expression was determined with semiquantity RT-PCR using beta-actin as internal reference.

RESULTThe level of adiponetin mRNA in 3T3-L1 adipocyte was increased after treated with berberine only (P < 0.05), the effect of berberine was inhibited by high concentration insulin (P < 0.05).

CONCLUSIONIn vitro, berberine increases the expression of adiponectin in 3T3-L1 adipocyte, insulin inhibits the effect of berberine.

3T3-L1 Cells ; metabolism ; Adipocytes ; cytology ; metabolism ; Adiponectin ; Animals ; Berberine ; pharmacology ; Insulin ; pharmacology ; Intercellular Signaling Peptides and Proteins ; biosynthesis ; genetics ; Mice ; RNA, Messenger ; biosynthesis ; genetics

BACKGROUNDEndothelial dysfunction is a key event in the onset and progression of atherosclerosis in diabetic patients. Apoptosis may lead to endothelial dysfunction and contribute to vascular complications. However, no study has addressed apoptosis in human umbilical vein endothelial cells (HUVECs) induced by an intermittent high-glucose media and its association with adiponectin receptor 1 (adipoR1), adipoR2, or adenosine monophosphate (AMP)-activated protein kinase (AMPK).

METHODSHUVECs were cultured in continuous normal glucose (5.5 mmol/L), continuous high glucose (25 mmol/L), alternating normal and high glucose and mannitol. In the alternating normal and high-glucose media, HUVECs were treated under different conditions. First, cells were transfected with the adipoR1-specific small-interfering RNA (siRNA) and then stimulated with globular adiponectin (gAD). Second, cells were cultured in both gAD and the AMPK activator 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR). Third, cells were cultured in the AMPK inhibitor adenine-9-β-D-arabino-furanoside (araA), gAD, and in AICAR.

RESULTSHUVEC apoptosis increased more significantly in an intermittent high-glucose medium than in a constant high-glucose medium. HUVEC apoptosis induced by an intermittent high-glucose medium was inhibited when the cells were pretreated with 3 µg/ml gAD, which rapidly activated AMPK and adipoR1 in HUVECs. However, adipoR2 was not activated.

CONCLUSIONSWe found that adipoR1, not adipoR2, is involved in mediating intermittent high-concentration glucose-evoked apoptosis in endothelial cells. gAD activated AMPK through adipoR1, leads to the partial inhibition of HUVEC apoptosis. A fluctuating glucose medium is more harmful than a constant high-glucose medium to endothelial cells.

AMP-Activated Protein Kinases ; antagonists & inhibitors ; genetics ; metabolism ; Adiponectin ; pharmacology ; Aminoimidazole Carboxamide ; analogs & derivatives ; pharmacology ; Apoptosis ; drug effects ; Glucose ; pharmacology ; Human Umbilical Vein Endothelial Cells ; cytology ; drug effects ; metabolism ; Humans ; RNA, Small Interfering ; Receptors, Adiponectin ; genetics ; metabolism ; Ribonucleotides ; pharmacology ; Signal Transduction ; drug effects ; genetics

Adipokines, the bioactive factors derived mainly from adipocytes, regulate pancreatic beta-cell function including insulin secretion, gene expression and apoptosis. In this review, we propose that adipokines influence beta-cell function through three interdependent pathways. The first is through regulating lipid and glucose metabolism in beta-cells. The second implicates the change of ion channel opening and closing in beta-cells. The third pathway is via the modification of insulin sensitivity of beta-cells. The endocrine function of adipocytes is dynamic, and the secretion of various adipokines changes under different metabolic conditions. During the progression from the normal state to obesity and to type 2 diabetes, adipokines contribute to the occurrence and development of beta-cell dysfunction in type 2 diabetes.
Adipocytes ; physiology ; Adiponectin ; physiology ; Animals ; Diabetes Mellitus, Type 2 ; physiopathology ; Glucose ; metabolism ; Humans ; Insulin ; pharmacology ; Insulin-Secreting Cells ; physiology ; Leptin ; physiology ; Lipid Metabolism