The effect of Fructus Mume formula and its separated prescription extract on insulin resis- tance in type 2 diabetic rats was investigated. The rat model of type 2 diabetes was established by feed- ing on a high-fat d...The effect of Fructus Mume formula and its separated prescription extract on insulin resis- tance in type 2 diabetic rats was investigated. The rat model of type 2 diabetes was established by feed- ing on a high-fat diet for 8 weeks and by subsequently intravenous injection of small doses of strepto- zotocin. Rats in treatment groups, including the Fructus Mume formula treatment group （FM）, the cold property herbs of Fructus Mume formula treatment group （CFM）, the warm property herbs of Fructus Mume formula treatment group （WFM）, were administrated with Fructus Mume formula and its sepa- rated prescription extract by gavage, while the rats in diabetic model group （DM） and metformin group （MET） were given by gavage with normal saline and metformin correspondingly. The body weight be- fore and after treatment was measured, and the oral glucose tolerance test （OGTT） and the insulin re- lease test （IRT） were performed. The homeostasis model assessment-insulin resistance index （HOMA-IR） was calculated. The protein and mRNA expression levels of Insr, β-arrestin-2, Its-1 and Glut-4 in the liver, skeletal muscle and fat tissues were detected by using Western blotting and RT-PCR respectively. The results demonstrated that, as compared with DM group, OGTT, IRT （0 h, 1 h） levels and HOMR-IR in treatment groups were all reduced, meanwhile their protein and mRNA expression levels of Insr, Irs-1 and Glut-4 in the liver, skeletal muscle and fat tissues were obviously increased, and their protein and mRNA expression levels of β-arrestin-2 in the liver and skeletal muscle tissues were also markedly increased. It was suggested that the Fructus Mume formula and its separated prescription extracts could effectively improve insulin resistance in type 2 diabetic rats, which might be related to the up-regulated expression of Insr, Irs-1 and Glut-4 in the liver, skeletal muscle and fat tissues, and β-arrestin-2 in the liver and skeletal muscle tissues.展开更多
BACKGROUND: The increased β-arrestin-2 and its combination with G-protein-coupled receptors (GPCRs) lead to GPCRs desensitization. The latter may be responsible for decreased contractile reactivity in the mesenteric ...BACKGROUND: The increased β-arrestin-2 and its combination with G-protein-coupled receptors (GPCRs) lead to GPCRs desensitization. The latter may be responsible for decreased contractile reactivity in the mesenteric arteries of cirrhotic patients and rats. The present study is to investigate the machinery changes of α-adrenergic receptors and G proteins and their roles in the contractility of mesenteric arteries of cirrhotic patients and animal models. METHODS: Patients with cirrhosis due to hepatitis B and cirrhotic rats induced by CCl 4 were studied. Mesenteric artery contractility in response to norepinephrine was determined by a vessel perfusion system. The contractile effect of G protein-coupled receptor kinase-2 (GRK-2) inhibitor on the mesenteric artery was evaluated. The protein expression of the α 1 adrenergic receptor, G proteins, β-arrestin-2, GRK-2 as well as the activity of Rho associated coiled-coil forming protein kinase-1 (ROCK-1) were measured by Western blot. In addition, the interaction of α 1 adrenergic receptor with β-arrestin-2 was assessed by co-immunoprecipitation. RESULTS: The portal vein pressure of cirrhotic patients and rats was significantly higher than that of controls. The doseresponse curve to norepinephrine in mesenteric arteriole was shifted to the right, and EC 50 was significantly increased in cirrhotic patients and rats. There were no significant differences in the expressions of the α 1 adrenergic receptor and G proteins in the cirrhotic group compared with the controls. However, the protein expressions of GRK-2 and β-arrestin-2 were significantly elevated in cirrhotic patients and rats compared with those of the controls. The interaction of the α 1 adrenergic receptor and β-arrestin-2 was significantly aggravated. This interaction was significantly reversed by GRK-2 inhibitor. Both the protein expression and activity of ROCK-1 were significantly decreased in the mesenteric artery in patients with cirrhosis compared with those of the controls, and this phenomenon wa展开更多
BACKGROUND Portal hypertension,a common complication associated with liver cirrhosis,can result in variceal bleeding,which greatly impacts patient survival.Recently,β-arrestin-2 has been shown to predict the acute he...BACKGROUND Portal hypertension,a common complication associated with liver cirrhosis,can result in variceal bleeding,which greatly impacts patient survival.Recently,β-arrestin-2 has been shown to predict the acute hemodynamic response to nonselectiveβ-blocker therapy for cirrhotic portal hypertension.However,more data is needed on the long-term effects of and changes inβ-arrestin-2 following nonselectiveβ-blocker therapy.AIM To investigate the expression and role ofβ-Arrestin-2 in predicting the long-term response to nonselectiveβ-blockers in cirrhotic portal hypertensive patients.METHODS We prospectively enrolled 91 treatment-naïve patients with cirrhotic portal hypertension.Baseline clinical and laboratory data were obtained.Gastroscopy was performed for grading and treating varices and obtaining gastric antral biopsies.We measured the serum and antral expression ofβ-arrestin-2 and obtained Doppler measurement of the portal vein congestion index.Treatment with nonselectiveβ-blockers was then started.The patients were followed up for 18 mo,after which they have undergone a repeat antral biopsy and re-evaluation of the portal vein congestion index.RESULTS A higher serum level and antral expression ofβ-arrestin-2 was associated with longer bleedingfree intervals,greater reduction in the portal vein congestion index,and improved grade of varices.Among patients with a lowβ-arrestin-2 expression,17.6%were nonselectiveβ-blocker responders,whereas,among those with high expression,95.1%were responders(P<0.001).A serumβ-arrestin-2 value≥2.23 ng/mL was associated with a lower likelihood of variceal bleeding(90%sensitivity and 71%specificity).β-arrestin-2 expression significantly decreased after nonselectiveβ-blocker therapy.CONCLUSIONβ-arrestin-2 expression in cirrhotic portal hypertension predicts the clinical response to long-term nonselectiveβ-blocker treatment.Serumβ-arrestin-2 is a potential noninvasive biomarker for selecting the candidate patients for nonselectiveβ-blockers.展开更多
Insulin-like growth factor-1 receptor(IGF-1R) has been made an attractive anticancer target due to its overexpression in cancers.However,targeting it has often produced the disappointing results as the role played by ...Insulin-like growth factor-1 receptor(IGF-1R) has been made an attractive anticancer target due to its overexpression in cancers.However,targeting it has often produced the disappointing results as the role played by cross talk with numerous downstream signalings.Here,we report a disobliging IGF-1R signaling which promotes growth of cancer through triggering the E3 ubiquitin ligase MEX3A-mediated degradation of RIG-I.The active β-arrestin-2 scaffolds this disobliging signaling to talk with MEX3A.In response to ligands,IGF-1Rβ activated the basal βarr2 into its active state by phosphorylating the interdomain domain on Tyr64 and Tyr250,opening the middle loop(Leu130-Cys141) to the RING domain of MEX3A through the conformational changes of βarr2.The models of βarr2/IGF-1Rβ and βarr2/MEX3A could interpret the mechanism of the activated-IGF-1R in triggering degradation of RIG-I.The assay of the mutants βarr2Y64Aand βarr2Y250Afurther confirmed the role of these two Tyr residues of the interlobe in mediating the talk between IGF-1Rβ and the RING domain of MEX3A.The truncated-βarr2 and the peptide ATQAIRIF,which mimicked the RING domain of MEX3A could prevent the formation of βarr2/IGF-1Rβ and βarr2/MEX3A complexes,thus blocking the IGF-1R-triggered RIG-I degradation.Degradation of RIG-I resulted in the suppression of the IFN-I-associated immune cells in the TME due to the blockade of the RIG-I-MAVS-IFN-I pathway.Poly(I:C) could reverse anti-PD-L1 insensitivity by recovery of RIG-I.In summary,we revealed a disobliging IGF-1R signaling by which IGF-1Rβ promoted cancer growth through triggering the MEX3A-mediated degradation of RIG-I.展开更多
Objective： To investigate the β2-adrenoceptor （ β 2AR）-β-arrestin2-nuclear factor- K B （NF- κ B） signal transduction pathway and the intervention effects of oxymatrine in a rat model of ulcerative colitis. Me...Objective： To investigate the β2-adrenoceptor （ β 2AR）-β-arrestin2-nuclear factor- K B （NF- κ B） signal transduction pathway and the intervention effects of oxymatrine in a rat model of ulcerative colitis. Methods： Forty SD rats were randomly divided into four groups, which included the normal control group, the model group, the mesalazine group and the oxymatrine treatment group, with 10 rats per group. Experimental colitis induced with trinitrobenzene sulfonic acid （TNBS） was established in each group except the normal control group, The rats in the oxymatrine treatment group were treated with intramuscular injection of oxymatrine 63 mg/（kg.d） for 15 days and the rats in the mesalazine group were treated with mesalazine solution 0.5 g/（kg.d） by gastric lavage for 15 days. The rats in the normal control group and model group were treated with 3 mL water by gastric lavage for 15 days. Diarrhea and bloody stool were carefully observed. Histological changes in colonic tissue were examined on day 7 in 2 rats per group that were randomly selected. The expression of β 2AR, β -arrestin2 and NF- κ B p65 in colon tissue and spleen lymphocytes were detected with immunohistochemistry and Western immunoblotting techniques on day 16 after fasting for 24 h. Six rats died of lavage with 2 each in the normal control, the model group and the mesalazine group; and were not included in the analysis. Results： The rats in the model group suffered from looser stool and bloody purulent stool after modeling. But in the oxymatrine and mesalazine groups, looser stool and bloody purulent stool reduced after treatment. And the colonic wall in the model group was thickened and the colon length shortened. The colon mucosa was congested in multiple areas with edema, erosion, superficial or linear ulcer and scar formation, while the intestinal mucosa injury reduced in the mesalazine and oxymatrine groups （P〈0.01）. In colonic mucosa and in spleen lymphocytes, compared with the normal control group, the exp展开更多
AIM To study the role and the possible mechanism of β-arrestin 2 in lipopolysaccharide(LPS)-induced liver injury in vivo and in vitro.METHODS Male β-arrestin 2^(+/+) and β-arrestin 2^(-/-)C57 BL/6 J mice were used ...AIM To study the role and the possible mechanism of β-arrestin 2 in lipopolysaccharide(LPS)-induced liver injury in vivo and in vitro.METHODS Male β-arrestin 2^(+/+) and β-arrestin 2^(-/-)C57 BL/6 J mice were used for in vivo experiments, and the mouse macrophage cell line RAW264.7 was used for in vitro experiments. The animal model was established via intraperitoneal injection of LPS or physiological sodium chloride solution. Blood samples and liver tissues were collected to analyze liver injury and levels of pro-inflammatory cytokines. Cultured cell extracts were collected to analyze the production of pro-inflammatory cytokines and expression of key molecules involved in the TLR4/NF-κB signaling pathway.RESULTS Compared with wild-type mice, the β-arrestin 2 knockout mice displayed more severe LPS-induced liver injury and significantly higher levels of proinflammatory cytokines, including interleukin(IL)-1β, IL-6, tumor necrosis factor(TNF)-α, and IL-10. Compared with the control group, pro-inflammatory cytokines(including IL-1β, IL-6, TNF-α, and IL-10) produced by RAW264.7 cells in the β-arrestin 2 si RNA group were significantly increased at 6 h after treatment with LPS. Further, key molecules involved in the TLR4/NF-κB signaling pathway, including phosphoIκBα and phosho-p65, were upregulated.CONCLUSION β-arrestin 2 can protect liver tissue from LPS-induced injury via inhibition of TLR4/NF-κB signaling pathwaymediated inflammation.展开更多
基金supported by grants from the National Natural Science Foundation of China(No.81273683)the Foundation of Hubei Provincial Health Department(No.2012Z-Y04)
文摘The effect of Fructus Mume formula and its separated prescription extract on insulin resis- tance in type 2 diabetic rats was investigated. The rat model of type 2 diabetes was established by feed- ing on a high-fat diet for 8 weeks and by subsequently intravenous injection of small doses of strepto- zotocin. Rats in treatment groups, including the Fructus Mume formula treatment group （FM）, the cold property herbs of Fructus Mume formula treatment group （CFM）, the warm property herbs of Fructus Mume formula treatment group （WFM）, were administrated with Fructus Mume formula and its sepa- rated prescription extract by gavage, while the rats in diabetic model group （DM） and metformin group （MET） were given by gavage with normal saline and metformin correspondingly. The body weight be- fore and after treatment was measured, and the oral glucose tolerance test （OGTT） and the insulin re- lease test （IRT） were performed. The homeostasis model assessment-insulin resistance index （HOMA-IR） was calculated. The protein and mRNA expression levels of Insr, β-arrestin-2, Its-1 and Glut-4 in the liver, skeletal muscle and fat tissues were detected by using Western blotting and RT-PCR respectively. The results demonstrated that, as compared with DM group, OGTT, IRT （0 h, 1 h） levels and HOMR-IR in treatment groups were all reduced, meanwhile their protein and mRNA expression levels of Insr, Irs-1 and Glut-4 in the liver, skeletal muscle and fat tissues were obviously increased, and their protein and mRNA expression levels of β-arrestin-2 in the liver and skeletal muscle tissues were also markedly increased. It was suggested that the Fructus Mume formula and its separated prescription extracts could effectively improve insulin resistance in type 2 diabetic rats, which might be related to the up-regulated expression of Insr, Irs-1 and Glut-4 in the liver, skeletal muscle and fat tissues, and β-arrestin-2 in the liver and skeletal muscle tissues.
基金supported by a grant from the National Natural Science Foundation of China (30972920)
文摘BACKGROUND: The increased β-arrestin-2 and its combination with G-protein-coupled receptors (GPCRs) lead to GPCRs desensitization. The latter may be responsible for decreased contractile reactivity in the mesenteric arteries of cirrhotic patients and rats. The present study is to investigate the machinery changes of α-adrenergic receptors and G proteins and their roles in the contractility of mesenteric arteries of cirrhotic patients and animal models. METHODS: Patients with cirrhosis due to hepatitis B and cirrhotic rats induced by CCl 4 were studied. Mesenteric artery contractility in response to norepinephrine was determined by a vessel perfusion system. The contractile effect of G protein-coupled receptor kinase-2 (GRK-2) inhibitor on the mesenteric artery was evaluated. The protein expression of the α 1 adrenergic receptor, G proteins, β-arrestin-2, GRK-2 as well as the activity of Rho associated coiled-coil forming protein kinase-1 (ROCK-1) were measured by Western blot. In addition, the interaction of α 1 adrenergic receptor with β-arrestin-2 was assessed by co-immunoprecipitation. RESULTS: The portal vein pressure of cirrhotic patients and rats was significantly higher than that of controls. The doseresponse curve to norepinephrine in mesenteric arteriole was shifted to the right, and EC 50 was significantly increased in cirrhotic patients and rats. There were no significant differences in the expressions of the α 1 adrenergic receptor and G proteins in the cirrhotic group compared with the controls. However, the protein expressions of GRK-2 and β-arrestin-2 were significantly elevated in cirrhotic patients and rats compared with those of the controls. The interaction of the α 1 adrenergic receptor and β-arrestin-2 was significantly aggravated. This interaction was significantly reversed by GRK-2 inhibitor. Both the protein expression and activity of ROCK-1 were significantly decreased in the mesenteric artery in patients with cirrhosis compared with those of the controls, and this phenomenon wa
文摘BACKGROUND Portal hypertension,a common complication associated with liver cirrhosis,can result in variceal bleeding,which greatly impacts patient survival.Recently,β-arrestin-2 has been shown to predict the acute hemodynamic response to nonselectiveβ-blocker therapy for cirrhotic portal hypertension.However,more data is needed on the long-term effects of and changes inβ-arrestin-2 following nonselectiveβ-blocker therapy.AIM To investigate the expression and role ofβ-Arrestin-2 in predicting the long-term response to nonselectiveβ-blockers in cirrhotic portal hypertensive patients.METHODS We prospectively enrolled 91 treatment-naïve patients with cirrhotic portal hypertension.Baseline clinical and laboratory data were obtained.Gastroscopy was performed for grading and treating varices and obtaining gastric antral biopsies.We measured the serum and antral expression ofβ-arrestin-2 and obtained Doppler measurement of the portal vein congestion index.Treatment with nonselectiveβ-blockers was then started.The patients were followed up for 18 mo,after which they have undergone a repeat antral biopsy and re-evaluation of the portal vein congestion index.RESULTS A higher serum level and antral expression ofβ-arrestin-2 was associated with longer bleedingfree intervals,greater reduction in the portal vein congestion index,and improved grade of varices.Among patients with a lowβ-arrestin-2 expression,17.6%were nonselectiveβ-blocker responders,whereas,among those with high expression,95.1%were responders(P<0.001).A serumβ-arrestin-2 value≥2.23 ng/mL was associated with a lower likelihood of variceal bleeding(90%sensitivity and 71%specificity).β-arrestin-2 expression significantly decreased after nonselectiveβ-blocker therapy.CONCLUSIONβ-arrestin-2 expression in cirrhotic portal hypertension predicts the clinical response to long-term nonselectiveβ-blocker treatment.Serumβ-arrestin-2 is a potential noninvasive biomarker for selecting the candidate patients for nonselectiveβ-blockers.
基金supported by Beijing Natural Science Foundation(7222253,China)National Natural Science Foundation of China(81973350/82173841)supported by Beijing Natural Science Foundation(7212149,China)。
文摘Insulin-like growth factor-1 receptor(IGF-1R) has been made an attractive anticancer target due to its overexpression in cancers.However,targeting it has often produced the disappointing results as the role played by cross talk with numerous downstream signalings.Here,we report a disobliging IGF-1R signaling which promotes growth of cancer through triggering the E3 ubiquitin ligase MEX3A-mediated degradation of RIG-I.The active β-arrestin-2 scaffolds this disobliging signaling to talk with MEX3A.In response to ligands,IGF-1Rβ activated the basal βarr2 into its active state by phosphorylating the interdomain domain on Tyr64 and Tyr250,opening the middle loop(Leu130-Cys141) to the RING domain of MEX3A through the conformational changes of βarr2.The models of βarr2/IGF-1Rβ and βarr2/MEX3A could interpret the mechanism of the activated-IGF-1R in triggering degradation of RIG-I.The assay of the mutants βarr2Y64Aand βarr2Y250Afurther confirmed the role of these two Tyr residues of the interlobe in mediating the talk between IGF-1Rβ and the RING domain of MEX3A.The truncated-βarr2 and the peptide ATQAIRIF,which mimicked the RING domain of MEX3A could prevent the formation of βarr2/IGF-1Rβ and βarr2/MEX3A complexes,thus blocking the IGF-1R-triggered RIG-I degradation.Degradation of RIG-I resulted in the suppression of the IFN-I-associated immune cells in the TME due to the blockade of the RIG-I-MAVS-IFN-I pathway.Poly(I:C) could reverse anti-PD-L1 insensitivity by recovery of RIG-I.In summary,we revealed a disobliging IGF-1R signaling by which IGF-1Rβ promoted cancer growth through triggering the MEX3A-mediated degradation of RIG-I.
基金Supported by the National Natural Science Foundation of China (No.30772878)
文摘Objective： To investigate the β2-adrenoceptor （ β 2AR）-β-arrestin2-nuclear factor- K B （NF- κ B） signal transduction pathway and the intervention effects of oxymatrine in a rat model of ulcerative colitis. Methods： Forty SD rats were randomly divided into four groups, which included the normal control group, the model group, the mesalazine group and the oxymatrine treatment group, with 10 rats per group. Experimental colitis induced with trinitrobenzene sulfonic acid （TNBS） was established in each group except the normal control group, The rats in the oxymatrine treatment group were treated with intramuscular injection of oxymatrine 63 mg/（kg.d） for 15 days and the rats in the mesalazine group were treated with mesalazine solution 0.5 g/（kg.d） by gastric lavage for 15 days. The rats in the normal control group and model group were treated with 3 mL water by gastric lavage for 15 days. Diarrhea and bloody stool were carefully observed. Histological changes in colonic tissue were examined on day 7 in 2 rats per group that were randomly selected. The expression of β 2AR, β -arrestin2 and NF- κ B p65 in colon tissue and spleen lymphocytes were detected with immunohistochemistry and Western immunoblotting techniques on day 16 after fasting for 24 h. Six rats died of lavage with 2 each in the normal control, the model group and the mesalazine group; and were not included in the analysis. Results： The rats in the model group suffered from looser stool and bloody purulent stool after modeling. But in the oxymatrine and mesalazine groups, looser stool and bloody purulent stool reduced after treatment. And the colonic wall in the model group was thickened and the colon length shortened. The colon mucosa was congested in multiple areas with edema, erosion, superficial or linear ulcer and scar formation, while the intestinal mucosa injury reduced in the mesalazine and oxymatrine groups （P〈0.01）. In colonic mucosa and in spleen lymphocytes, compared with the normal control group, the exp
基金Supported by the National Natural Science Foundation of China,No.81470848the Breeding Foundation for Young Pioneers’Research of Sun Yat-sen University,No.14ykpy27
文摘AIM To study the role and the possible mechanism of β-arrestin 2 in lipopolysaccharide(LPS)-induced liver injury in vivo and in vitro.METHODS Male β-arrestin 2^(+/+) and β-arrestin 2^(-/-)C57 BL/6 J mice were used for in vivo experiments, and the mouse macrophage cell line RAW264.7 was used for in vitro experiments. The animal model was established via intraperitoneal injection of LPS or physiological sodium chloride solution. Blood samples and liver tissues were collected to analyze liver injury and levels of pro-inflammatory cytokines. Cultured cell extracts were collected to analyze the production of pro-inflammatory cytokines and expression of key molecules involved in the TLR4/NF-κB signaling pathway.RESULTS Compared with wild-type mice, the β-arrestin 2 knockout mice displayed more severe LPS-induced liver injury and significantly higher levels of proinflammatory cytokines, including interleukin(IL)-1β, IL-6, tumor necrosis factor(TNF)-α, and IL-10. Compared with the control group, pro-inflammatory cytokines(including IL-1β, IL-6, TNF-α, and IL-10) produced by RAW264.7 cells in the β-arrestin 2 si RNA group were significantly increased at 6 h after treatment with LPS. Further, key molecules involved in the TLR4/NF-κB signaling pathway, including phosphoIκBα and phosho-p65, were upregulated.CONCLUSION β-arrestin 2 can protect liver tissue from LPS-induced injury via inhibition of TLR4/NF-κB signaling pathwaymediated inflammation.
