AIM： To determine circulating and hepatic adiponectin in rodents with fatty liver disease or liver cirrhosis and investigate expression of the adiponectin receptors AdipoR1 on the mRNA and protein level and AdipoR2 o...AIM： To determine circulating and hepatic adiponectin in rodents with fatty liver disease or liver cirrhosis and investigate expression of the adiponectin receptors AdipoR1 on the mRNA and protein level and AdipoR2 on the mRNA level. METHODS： Fat fed rats were used as a model for fatty liver disease and bile duct ligation in mice to investigate cirrhotic liver. Expression of AdipoR1 and AdipoR2 mRNA was determined by real time RT-PCR. AdipoR1 protein was analysed by immunoblot. Adiponectin was measured by ELISA. RESULTS： Systemic adiponectin is reduced in fatfed rats but is elevated in mice after bile duct ligation （BDL）. Hepatic adiponectin protein is lower in steatotic liver but not in the liver of BE）L-mice when compared to controls. Adiponectin mRNA was not detected in human liver samples or primary human hepatocytes nor in rat liver but recombinant adiponectin is taken up by isolated hepatocytes in-vitro. AdipoR1 mRNA and AdipoR1 protein levels are similar in the liver tissue of control and fat fed animals whereas AdipoR2 mRNA is induced. AdipoR2 mRNA and AdipoR1 mRNA and protein is suppressed in the liver of BDL-mice. CONCLUSION： Our studies show reduced circulating adiponectin in a rat model of fatty liver disease whereas circulating adiponectin is elevated in a mouse model of cirrhosis and similar findings have been described in humans. Diminished hepatic expression of adiponectin receptors was only found in liver cirrhosis.展开更多
[ Objective] To clone and analyze the sequence of Adiponectin receptor 1 （ AdipoR1 ） and receptor 2 （AdipoR2） cDNA of Guangxi Bama mini-pig. [Method] The Adiponectin receptors cDNAs were amplified by RT-PCR using ...[ Objective] To clone and analyze the sequence of Adiponectin receptor 1 （ AdipoR1 ） and receptor 2 （AdipoR2） cDNA of Guangxi Bama mini-pig. [Method] The Adiponectin receptors cDNAs were amplified by RT-PCR using skeletal muscle total RNA as template and then ligated into pMD18-T vector after purification. The recombinant pMD18-T vector was transformed into the E. coil DH5α for identification and sequencing. And the results were compared with the cDNA sequence from other species. [Result] The fragments, 1 128 bp and 1 161 bp in size, were amplified by RT-PCR and respectively consistent with the coding sequence of AdipoR1 gene and AdipoR2 gene. The homology analysis showed that the sequences of AdipoR1 gene and AdipoR2 gene were respectively 99.8% and 99.7% homologous to the sequence of domestic pig reported in GenBank with one base and three base missense mutations correspondingly. [ Conclusion] The AdipoR1 gene and AdipoR2. gene were successfully amplified from Guangxi Bama mini-pig, laying the foundation for the further study of the biological function of AdipoR genes and the design of novel drugs with AdipoR as target.展开更多
Pancreatic ductal adenocarcinoma (PDAC) is the fourth cause of cancer death with an overall survival of 5% at five years. The development of PDAC is characteristically associated to the accumulation of distinctive gen...Pancreatic ductal adenocarcinoma (PDAC) is the fourth cause of cancer death with an overall survival of 5% at five years. The development of PDAC is characteristically associated to the accumulation of distinctive genetic mutations and is preceded by the exposure to several risk factors. Epidemiology has demonstrated that PDAC risk factors may be non-modifiable risks (sex, age, presence of genetic mutations, ethnicity) and modifiable and co-morbidity factors related to the specific habits and lifestyle. Recently it has become evident that obesity and diabetes are two important modifiable risk factors for PDAC. Obesity and diabetes are complex systemic and intertwined diseases and, over the years, experimental evidence indicate that insulin-resistance, alteration of adipokines, especially leptin and adiponectin, oxidative stress and inflammation may play a role in PDAC. Peroxisome proliferator activated receptor-γ (PPARγ) is a nuclear receptor transcription factor that is implicated in the regulation of metabolism, differentiation and inflammation. PPARγ is a key regulator of adipocytes differentiation, regulates insulin and adipokines production and secretion, may modulate inflammation, and it is implicated in PDAC. PPARγ agonists are used in the treatment of diabetes and oxidative stress-associated diseases and have been evaluated for the treatment of PDAC. PPARγ is at the cross-road of diabetes, obesity, and PDAC and it is an interesting target to pharmacologically prevent PDAC in obese and diabetic patients.展开更多
In order to confirm whether the mRNA levels of adiponectin in adipose tissue and mRNA levels of AdipoR1 in the skeletal muscles were correlated with the serum parameters of glucose and lipid metabolism and to clarify ...In order to confirm whether the mRNA levels of adiponectin in adipose tissue and mRNA levels of AdipoR1 in the skeletal muscles were correlated with the serum parameters of glucose and lipid metabolism and to clarify the regulation of adiponectin receptor gene expression in diabetic states, serum adiponectin, mRNA levels of adiponectin in adipose tissue and mRNA levels of AdipoR1 in the skeletal muscles were examined in type 2 diabetic rats. The model of type 2 diabetes was prepared by feeding high fat diet and injecting low dosage of streptozotocin (STZ). The diabetic rats were screened out by oral glucose tolerance test. One group of type 2 diabetic rats received rosiglitazone. The serum adiponectin concentration was detected by using ELISA and mRNA levels were examined by RT-PCR. The serum adiponectin levels and mRNA levels of adiponectin in adipose tissue of type 2 diabetic rats were significantly decreased as compared with the normal control rats (P<0.05, P<0.01 respectively). No siglificant changes were observed in the expression of adiponectin receptor 1 in the skeletal muscle of type 2 diabetic rats. The mRNA levels of adiponectin in adipose tissue were reversely correlated with serum insulin (r=-0.66, P<0.05), triglyceride (r=-0.58, P<0.05), cholesterol (r=-0.49, P<0.05), interleukin-6 (r=-0.49, P<0.05) and tumor necrosis factor (r=-0.43, P<0.05). The expression of adiponectin receptors was not altered in the skeletal muscle of Type 2 diabetic rats. The decreased serum adiponectin was caused by the decreased expression of adiponectin mRNA in adipose tissue rather than the adiponectin receptors in the skeletal muscle, which could be improved by rosiglitazone.展开更多
In eukaryotic cells, receptor endocytosis is a key event regulating signaling transduction. Adiponectin receptors belong to a new receptor family that is distinct from G-protein-coupled receptors and has critical role...In eukaryotic cells, receptor endocytosis is a key event regulating signaling transduction. Adiponectin receptors belong to a new receptor family that is distinct from G-protein-coupled receptors and has critical roles in the pathogenesis of diabetes and metabolic syndrome. Here, we analyzed the endocytosis of adiponectin and adiponectin receptor 1 （AdipoR1） and found that they are both internalized into transferrin-positive compartments that follow similar traffic routes. Blocking clathrin-mediated endocytosis by expressing Eps15 mutants or depleting K^＋ trapped AdipoR1 at the plasma membrane, and K^＋ depletion abolished adiponectin internalization, indicating that the endocytosis of AdipoR1 and adiponectin is clathrin-dependent. Depletion of K^＋ and overexpression of Eps15 mutants enhance adiponectin- stimulated AMP-activated protein kinase phosphorylation, suggesting that the endocytosis of AdipoR1 might down-regulate adiponectin signaling. In addition, AdipoR1 colocalizes with the small GTPase Rab5, and a dominant negative Rab5 abrogates AdipoR1 endocytosis. These data indicate that AdipoR1 is internalized through a clathrin- and Rab5- dependent pathway and that endocytosis may play a role in the regulation of adiponectin signaling.展开更多
Background The genes encoding adiponectin receptor 1 （ADIPOR1） and small ubiquitin-like modifier 4 （SUM04） have been linked to anti-atherogenic effects, but little is known about whether polymorphisms in the two g...Background The genes encoding adiponectin receptor 1 （ADIPOR1） and small ubiquitin-like modifier 4 （SUM04） have been linked to anti-atherogenic effects, but little is known about whether polymorphisms in the two genes, acting separately or interacting, affect risk of coronary artery disease （CAD） without diabetes. Methods We genotyped 200 CAD patients without diabetes and 200 controls without CAD or diabetes at three single-nucleotide polymorphisms （SNPs） in ADIPOR1 and one SNP in SUM04, which were chosen based on previous studies. Potential associations were also explored between these SNPs and clinical characteristics of CAD without diabetes. Results Risk alleles at three SNPs inADIPOR1 （rs7539542-G, rs7514221-C and rs3737884-G） and the G allele at SNP rs237025 in SUM04 significantly increased risk of CAD without diabetes, with ORs ranging from 1.79 to 4.44. Carriers of any of these four risk alleles showed similar adverse clinical characteristics. Compared with individuals with a CC or GC genotype, those with a GG genotype at rs3737884 were at significantly higher risk of CAD that affected the left anterior descending coronary artery （OR： 6.77, P = 0.009）, the right coronary artery （OR： 4.81, P = 0.028） or a relatively large number of vessels （P = 0.04）. Individuals carrying a risk allele at one or more of the three SNPs in ADIPOR1 as well as a risk allele at the SNP in SUM04 were at significantly higher risk of CAD without diabetes than individuals not carrying any risk alleles （OR： 5.82, 95% CI： 1.23-27.7, P= 0.013）. Conelusions SNPs in ADIPORl and SUMO4 are associated with elevated risk of CAD without diabetes, and SNPs in the two genes may interact to jointly affect disease risk.展开更多
BACKGROUND Antagonists of cannabinoid type 1 receptor(CB1)have been shown to promote body weight loss and improve insulin sensitivity.Cannabinoids decrease adiponectin,and CB1 blocker increase adiponectin.However,the ...BACKGROUND Antagonists of cannabinoid type 1 receptor(CB1)have been shown to promote body weight loss and improve insulin sensitivity.Cannabinoids decrease adiponectin,and CB1 blocker increase adiponectin.However,the mediators of CB1 actions are not well defined.AIM To investigate whether the beneficial effects of CB1 inhibition are,at least in part,mediated by adiponectin.METHODS We compared metabolic and inflammatory phenotypes of wild-type(WT)mice,CB1-null(CB1^(-/-))and CB1/adiponectin double-knockout(DKO)mice.We assessed the insulin sensitivity using insulin tolerance test and glucose tolerance test,and inflammation using flow cytometry analysis of macrophages.RESULTS CB1^(-/-)mice exhibited significantly reduced body weight and fat mass when compared to WT mice.While no significance was found in total daily food intake and locomotor activity,CB1^(-/-)mice showed increased energy expenditure,enhanced thermogenesis in brown adipose tissue(BAT),and improved insulin sensitivity compared to WT mice.DKO showed no difference in body weight,adiposity,nor insulin sensitivity;only showed a modestly elevated thermogenesis in BAT compared to CB1^(-/-)mice.The metabolic phenotype of DKO is largely similar to CB1^(-/-)mice,suggesting that adiponectin is not a key mediator of the metabolic effects of CB1.Interestingly,CB1^(-/-)mice showed reduced pro-inflammatory macrophage polarization in both peritoneal macrophages and adipose tissue macrophages compared to WT mice;in contrast,DKO mice exhibited increased pro-inflammatory macrophage polarization in these macrophages compared to CB1^(-/-)mice,suggesting that adiponectin is an important mediator of the inflammatory effect of CB1.CONCLUSION Our findings reveal that CB1 functions through both adiponectin-dependent and adiponectin-independent mechanisms:CB1 regulates energy metabolism in an adiponectin-independent manner,and inflammation in an adiponectin-dependent manner.The differential effects of adiponectin on CB1-mediated metabolic and inflammatory functions should be taken into consideration in CB1 antagonist utilization.展开更多
基金Supported by a grant from the Deutsche Forschungsgemeinschaft (BU 1141/3-2)
文摘AIM： To determine circulating and hepatic adiponectin in rodents with fatty liver disease or liver cirrhosis and investigate expression of the adiponectin receptors AdipoR1 on the mRNA and protein level and AdipoR2 on the mRNA level. METHODS： Fat fed rats were used as a model for fatty liver disease and bile duct ligation in mice to investigate cirrhotic liver. Expression of AdipoR1 and AdipoR2 mRNA was determined by real time RT-PCR. AdipoR1 protein was analysed by immunoblot. Adiponectin was measured by ELISA. RESULTS： Systemic adiponectin is reduced in fatfed rats but is elevated in mice after bile duct ligation （BDL）. Hepatic adiponectin protein is lower in steatotic liver but not in the liver of BE）L-mice when compared to controls. Adiponectin mRNA was not detected in human liver samples or primary human hepatocytes nor in rat liver but recombinant adiponectin is taken up by isolated hepatocytes in-vitro. AdipoR1 mRNA and AdipoR1 protein levels are similar in the liver tissue of control and fat fed animals whereas AdipoR2 mRNA is induced. AdipoR2 mRNA and AdipoR1 mRNA and protein is suppressed in the liver of BDL-mice. CONCLUSION： Our studies show reduced circulating adiponectin in a rat model of fatty liver disease whereas circulating adiponectin is elevated in a mouse model of cirrhosis and similar findings have been described in humans. Diminished hepatic expression of adiponectin receptors was only found in liver cirrhosis.
基金Supported by Guangxi Science Foundation (0542025)~~
文摘[ Objective] To clone and analyze the sequence of Adiponectin receptor 1 （ AdipoR1 ） and receptor 2 （AdipoR2） cDNA of Guangxi Bama mini-pig. [Method] The Adiponectin receptors cDNAs were amplified by RT-PCR using skeletal muscle total RNA as template and then ligated into pMD18-T vector after purification. The recombinant pMD18-T vector was transformed into the E. coil DH5α for identification and sequencing. And the results were compared with the cDNA sequence from other species. [Result] The fragments, 1 128 bp and 1 161 bp in size, were amplified by RT-PCR and respectively consistent with the coding sequence of AdipoR1 gene and AdipoR2 gene. The homology analysis showed that the sequences of AdipoR1 gene and AdipoR2 gene were respectively 99.8% and 99.7% homologous to the sequence of domestic pig reported in GenBank with one base and three base missense mutations correspondingly. [ Conclusion] The AdipoR1 gene and AdipoR2. gene were successfully amplified from Guangxi Bama mini-pig, laying the foundation for the further study of the biological function of AdipoR genes and the design of novel drugs with AdipoR as target.
基金Supported by Fondo per gli Investimenti della Ricerca di BaseNo.RBAP10MY35_002+1 种基金Ente Cassa di Risparmio di Firenzeand Fior Gen ONLUS to Galli A
文摘Pancreatic ductal adenocarcinoma (PDAC) is the fourth cause of cancer death with an overall survival of 5% at five years. The development of PDAC is characteristically associated to the accumulation of distinctive genetic mutations and is preceded by the exposure to several risk factors. Epidemiology has demonstrated that PDAC risk factors may be non-modifiable risks (sex, age, presence of genetic mutations, ethnicity) and modifiable and co-morbidity factors related to the specific habits and lifestyle. Recently it has become evident that obesity and diabetes are two important modifiable risk factors for PDAC. Obesity and diabetes are complex systemic and intertwined diseases and, over the years, experimental evidence indicate that insulin-resistance, alteration of adipokines, especially leptin and adiponectin, oxidative stress and inflammation may play a role in PDAC. Peroxisome proliferator activated receptor-γ (PPARγ) is a nuclear receptor transcription factor that is implicated in the regulation of metabolism, differentiation and inflammation. PPARγ is a key regulator of adipocytes differentiation, regulates insulin and adipokines production and secretion, may modulate inflammation, and it is implicated in PDAC. PPARγ agonists are used in the treatment of diabetes and oxidative stress-associated diseases and have been evaluated for the treatment of PDAC. PPARγ is at the cross-road of diabetes, obesity, and PDAC and it is an interesting target to pharmacologically prevent PDAC in obese and diabetic patients.
文摘In order to confirm whether the mRNA levels of adiponectin in adipose tissue and mRNA levels of AdipoR1 in the skeletal muscles were correlated with the serum parameters of glucose and lipid metabolism and to clarify the regulation of adiponectin receptor gene expression in diabetic states, serum adiponectin, mRNA levels of adiponectin in adipose tissue and mRNA levels of AdipoR1 in the skeletal muscles were examined in type 2 diabetic rats. The model of type 2 diabetes was prepared by feeding high fat diet and injecting low dosage of streptozotocin (STZ). The diabetic rats were screened out by oral glucose tolerance test. One group of type 2 diabetic rats received rosiglitazone. The serum adiponectin concentration was detected by using ELISA and mRNA levels were examined by RT-PCR. The serum adiponectin levels and mRNA levels of adiponectin in adipose tissue of type 2 diabetic rats were significantly decreased as compared with the normal control rats (P<0.05, P<0.01 respectively). No siglificant changes were observed in the expression of adiponectin receptor 1 in the skeletal muscle of type 2 diabetic rats. The mRNA levels of adiponectin in adipose tissue were reversely correlated with serum insulin (r=-0.66, P<0.05), triglyceride (r=-0.58, P<0.05), cholesterol (r=-0.49, P<0.05), interleukin-6 (r=-0.49, P<0.05) and tumor necrosis factor (r=-0.43, P<0.05). The expression of adiponectin receptors was not altered in the skeletal muscle of Type 2 diabetic rats. The decreased serum adiponectin was caused by the decreased expression of adiponectin mRNA in adipose tissue rather than the adiponectin receptors in the skeletal muscle, which could be improved by rosiglitazone.
文摘In eukaryotic cells, receptor endocytosis is a key event regulating signaling transduction. Adiponectin receptors belong to a new receptor family that is distinct from G-protein-coupled receptors and has critical roles in the pathogenesis of diabetes and metabolic syndrome. Here, we analyzed the endocytosis of adiponectin and adiponectin receptor 1 （AdipoR1） and found that they are both internalized into transferrin-positive compartments that follow similar traffic routes. Blocking clathrin-mediated endocytosis by expressing Eps15 mutants or depleting K^＋ trapped AdipoR1 at the plasma membrane, and K^＋ depletion abolished adiponectin internalization, indicating that the endocytosis of AdipoR1 and adiponectin is clathrin-dependent. Depletion of K^＋ and overexpression of Eps15 mutants enhance adiponectin- stimulated AMP-activated protein kinase phosphorylation, suggesting that the endocytosis of AdipoR1 might down-regulate adiponectin signaling. In addition, AdipoR1 colocalizes with the small GTPase Rab5, and a dominant negative Rab5 abrogates AdipoR1 endocytosis. These data indicate that AdipoR1 is internalized through a clathrin- and Rab5- dependent pathway and that endocytosis may play a role in the regulation of adiponectin signaling.
基金Acknowledgments This study was funded by the National Natural Science Foundation of China （81570323, 30972709, 81061120527, 81241082） and the 12th Five-Year National Program of the Ministry of Scientific Technology （2012BAI10B01）. We thank Liu M and Zhou L from Beijing Hospital for providing experimental data, the nurses from Beijing Anzhen Hospital for collecting specimens, and the study volunteers.
文摘Background The genes encoding adiponectin receptor 1 （ADIPOR1） and small ubiquitin-like modifier 4 （SUM04） have been linked to anti-atherogenic effects, but little is known about whether polymorphisms in the two genes, acting separately or interacting, affect risk of coronary artery disease （CAD） without diabetes. Methods We genotyped 200 CAD patients without diabetes and 200 controls without CAD or diabetes at three single-nucleotide polymorphisms （SNPs） in ADIPOR1 and one SNP in SUM04, which were chosen based on previous studies. Potential associations were also explored between these SNPs and clinical characteristics of CAD without diabetes. Results Risk alleles at three SNPs inADIPOR1 （rs7539542-G, rs7514221-C and rs3737884-G） and the G allele at SNP rs237025 in SUM04 significantly increased risk of CAD without diabetes, with ORs ranging from 1.79 to 4.44. Carriers of any of these four risk alleles showed similar adverse clinical characteristics. Compared with individuals with a CC or GC genotype, those with a GG genotype at rs3737884 were at significantly higher risk of CAD that affected the left anterior descending coronary artery （OR： 6.77, P = 0.009）, the right coronary artery （OR： 4.81, P = 0.028） or a relatively large number of vessels （P = 0.04）. Individuals carrying a risk allele at one or more of the three SNPs in ADIPOR1 as well as a risk allele at the SNP in SUM04 were at significantly higher risk of CAD without diabetes than individuals not carrying any risk alleles （OR： 5.82, 95% CI： 1.23-27.7, P= 0.013）. Conelusions SNPs in ADIPORl and SUMO4 are associated with elevated risk of CAD without diabetes, and SNPs in the two genes may interact to jointly affect disease risk.
基金Supported by the NIH,No.DK118334 and No.AG064869and the BrightFocus,No.A2019630S(to Sun Y).
文摘BACKGROUND Antagonists of cannabinoid type 1 receptor(CB1)have been shown to promote body weight loss and improve insulin sensitivity.Cannabinoids decrease adiponectin,and CB1 blocker increase adiponectin.However,the mediators of CB1 actions are not well defined.AIM To investigate whether the beneficial effects of CB1 inhibition are,at least in part,mediated by adiponectin.METHODS We compared metabolic and inflammatory phenotypes of wild-type(WT)mice,CB1-null(CB1^(-/-))and CB1/adiponectin double-knockout(DKO)mice.We assessed the insulin sensitivity using insulin tolerance test and glucose tolerance test,and inflammation using flow cytometry analysis of macrophages.RESULTS CB1^(-/-)mice exhibited significantly reduced body weight and fat mass when compared to WT mice.While no significance was found in total daily food intake and locomotor activity,CB1^(-/-)mice showed increased energy expenditure,enhanced thermogenesis in brown adipose tissue(BAT),and improved insulin sensitivity compared to WT mice.DKO showed no difference in body weight,adiposity,nor insulin sensitivity;only showed a modestly elevated thermogenesis in BAT compared to CB1^(-/-)mice.The metabolic phenotype of DKO is largely similar to CB1^(-/-)mice,suggesting that adiponectin is not a key mediator of the metabolic effects of CB1.Interestingly,CB1^(-/-)mice showed reduced pro-inflammatory macrophage polarization in both peritoneal macrophages and adipose tissue macrophages compared to WT mice;in contrast,DKO mice exhibited increased pro-inflammatory macrophage polarization in these macrophages compared to CB1^(-/-)mice,suggesting that adiponectin is an important mediator of the inflammatory effect of CB1.CONCLUSION Our findings reveal that CB1 functions through both adiponectin-dependent and adiponectin-independent mechanisms:CB1 regulates energy metabolism in an adiponectin-independent manner,and inflammation in an adiponectin-dependent manner.The differential effects of adiponectin on CB1-mediated metabolic and inflammatory functions should be taken into consideration in CB1 antagonist utilization.
基金Acknowledgment This research was supported by grants from the American Diabetes Association （1-11-JF56） and the Natural Science Foundation of China （30900592, 81170199） （to YJW） , and NIH （ HL-63828, HL-096686 ） and American Diabetes Association （7-11-BS-93） （to XLM）.
