Effect of Yishen Daluo Prescription on Rho/ROCK Signaling Pathway in EAE Mice Based on Silencing of β-arrestin1 / 中国实验方剂学杂志

ObjectiveTo investigate the effects of Yishen Daluo prescription （YSDL） on Ras homolog（Rho）/Rho-associated coiled-coil containing protein kinase（ROCK）signaling pathway in mice with experimental autoimmune encephalomyelitis （EAE） based on the silencing of β-arrestin1 gene. MethodSixty C57BL/6 female mice were randomly divided into a blank group， a model group， a virus group， a YSDL group， a virus + YSDL group， and a prednisone acetate group （hormone group）. The EAE model was induced in mice except for those in the normal group. Adeno-associated virus（AAV）solution （150 μL， 1×1011 vg·mL-1） was injected into the tail vein of each mouse in the virus group and the virus + YSDL group on the 4th day of immunization. Drugs were administered on the 8th day of modeling. Specifically， normal saline was given to the mice in the normal group，the model group，and the virus group at 10 mL∙kg-1， prednisone acetate suspension to those in the hormone group at 3.9 g∙kg-1，and YSDL to those in other groups at 20 g∙kg-1 for 14 consecutive days. The mice were weighed and scored every day. The neurological function scores of mice in each group were recorded every day after immunization. Hematoxylin-eosin （HE） staining was used to determine the inflammatory response and lesion location in the brain tissues and spinal cord tissues of mice. The protein expression of β-arrestin1，Ras homolog gene family member A（RhoA）， and Rho-associated coiled-coil forming protein kinase Ⅰ（ROCK Ⅰ） in spinal cord and brain tissues of EAE mice was determined by Western blot. ResultCompared with the model group， the virus group and the virus + YSDL group showed decreased neurological function scores （P<0.01），and the YSDL group also showed decreased neurological function scores（P<0.05）. HE results showed that there was obvious inflammatory reaction in the central nervous system （CNS） of the model group， which was alleviated to varying degrees in other groups compared with the model group. Western blot results showed that compared with the blank group， the model group showed increased protein expression levels of β-arrestin1， RhoA， and ROCK Ⅰ in the spinal cord tissues （P<0.01）. Compared with the model group， the virus group， the YSDL group， the virus + YSDL group， and the hormone group showed decreased protein expression levels of β-arrestin1， RhoA， and ROCKⅠ in the spinal cord tissues （P<0.01）. Compared with the blank group， the model group showed increased protein expression levels of β-arrestin1， RhoA， and ROCK Ⅰ in the brain tissues （P<0.01）. Compared with the model group， the virus group， the YSDL group， the virus + YSDL group， and the hormone group showed decreased protein expression level of β-arrestin1 in the brain tissues （P<0.01）， and the virus group and the YSDL group showed decreased protein expression levels of RhoA， and ROCKⅠ in the brain tissues （P<0.05）. Additionally， the virus + YSDL group and the hormone group showed decreased protein expression levels of RhoA and ROCKⅠ in the brain tissues （P<0.01）. ConclusionYSDL can improve the clinical symptoms of EAE mice and improve the inflammatory response of CNS. The mechanism is presumably attributed to the fact that YSDL inhibits the expression of β-arrestin1 in CNS，thereby reducing the expression of Rho/ROCK signaling pathway. Furthermore， YSDL may have a synergistic effect with the inhibition of β-arrestin1 gene expression.

Activation of insulin-like growth factor-1 receptor (IGF-1R) promotes growth of colorectal cancer through triggering the MEX3A-mediated degradation of RIG-I

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 βarr2Y64A and βarr2Y250A further 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.

Study on the mechanism of Yishen daluo decoction in alleviating nervous system inflammation in EAE model mice / 中国药房

OBJECTIVE To study the effects of Yishen daluo decoction on inflammatory factors and cyclic adenosine monophosphate（cAMP）/protein kinase A （PKA）/cAMP response element binding protein （CREB） signal pathway in experimental autoimmune encephalomyelitis （EAE） model mice by inhibiting the expressions of β-arrestin1， and to explore the mechanism of Yishen daluo decoction in the treatment of EAE. METHODS Sixty mice were randomly divided into normal group， model group， TCM group （Yishen daluo decoction 20 g/kg）， positive control group （prednisone acetate 3.9 mg/kg）， β-arrestin1 siRNA adeno- associated virus （AAV-β） group， AAV-β+TCM group， with 10 mice in each group. Except for normal group， EAE model was made in other groups. AAV-β group and AAV-β+TCM group were injected with AAV-β via tail vein to interfere with the expression of β -arrestin1 protein. Starting from the 8th day of modeling， they were given corresponding drug solution/normal saline intragastrically， once a day， for consecutive 14 days. The neurological function score of mice was detected； the pathological and morphological changes were observed in the brain and spinal cord tissues of mice； the serum levels of inflammatory factors [interleukin-2 （IL-2）， IL-23， interferon-γ （IFN-γ）] in mice were determined； the expressions of β-arrestin1， cAMP， PKA and CREB in brain and spinal cord were detected. RESULTS Compared with normal group， neurological function scores， serum levels of inflammatory factors， and protein expressions of β-arrestin1 in brain and spinal cord were significantly increased （P＜0.05 or P＜ 0.01）； protein expressions of PKA， CREB and cAMP in brain and spinal cord were decreased significantly（P＜0.05 or P＜0.01）. The deep staining of cellular shrinkage and aggregation of inflammatory cells were observed in most neurons of the brain and spinal cord， with varying degrees of demyelinating. Compared with model group， the neurological function scores， pathological changes in brain and spinal cord tissues， and most indicators （except for CREB and cAMP proteins in the brain tissue of AAV-β group） were significantly reversed （P＜0.05 or P＜0.01）.Compared with AAV- β group， the neurological function scores， the levels of IFN-γ in serum and β-arrestin1 in spinal cord were significantly decreased （P＜0.05 or P＜0.01）， PKA and cAMP in brain and spinal cord tissues were significantly increased in AAV- β +TCM group （P＜0.05 or P＜0.01）. CONCLUSIONS Yishen daluo decoction can inhibit the expression of β-arrestin1 in the central nervous system thus activating the cAMP/PKA/CREB signaling pathway， relieving nervous system inflammation， and ultimately alleviates the symptoms of EAE.

Advances in signaling pathway of 5-HT / 中国药理学通报

Classic serotonergic hallucinogens(also known as psychedelics)are powerful psychoactive substances that can induce profound alterations of human consciousness,emotion,and cognition. It is generally believed that the main target of psychedelics for their hallucinogenic effect is 5-hydroxytryptamine 2A receptor(5-HT

Inhibitory Effect of CCK-8 on Methamphetamine-Induced Apoptosis / 法医学杂志

OBJECTIVES@#To investigate the inhibitory effect of cholecystokinin octapeptide (CCK-8) binding to cholecystokinin 2 receptor (CCK2R) on methamphetamine (METH)-induced neuronal apoptosis, and to explore the signal transduction mechanism of β-arrestin 2 in CCK-8 inhibiting METH-induced neuronal apoptosis.@*METHODS@#SH-SY5Y cell line was cultured, and HEK293-CCK1R and HEK293-CCK2R cell line were constructed by lentivirus transfection. Small interfering RNA (siRNA) was used to knockdown the expression of β-arrestin 2. Annexin Ⅴ-FITC/PI staining and flow cytometry were used to detect the apoptotic rate of cells, and Western blotting was used to detect the expression of apoptosis-related proteins.@*RESULTS@#The apoptosis of SH-SY5Y cells was induced by 1 mmol/L and 2 mmol/L METH treatment, the number of nuclear fragmentation and pyknotic cells was significantly increased, and the expression of apoptosis-related proteins Bax and cleaved caspase-3 were increased. CCK-8 pre-treatment at the dose of 0.1 mmol/L and 1 mmol/L significantly reversed METH-induced apoptosis in SH-SY5Y cells, and inhibited cell nuclear fragmentation, pyknosis and the changes of apoptosis-related proteins induced by METH. In lentivirus transfected HEK293-CCK1R and HEK293-CCK2R cells, the results revealed that CCK-8 had no significant effect on METH-induced changes of apoptosis-related proteins in HEK293-CCK1R cells, but it could inhibit the expression level of apoptosis-related proteins in HEK293-CCK2R cells induced by METH. The inhibitory effect of CCK-8 on METH-induced apoptosis was blocked by the knockdown of β-arrestin 2 expression in SH-SY5Y cells.@*CONCLUSIONS@#CCK-8 can bind to CCK2R and exert an inhibitory effect on METH-induced apoptosis by activating the β-arrestin 2 signal.

β-arrestin 1 facilitates acetylation of IL-6 gene promoter to affect proliferation and apoptosis of non-small cell lung cancer cells / 肿瘤

Objective: To investigate the effects of β-arrestin 1 (ARRB1) on apoptosis and proliferation of non-small cell lung cancer (NSCLC) cells, and to explore the underlying molecular mechanism. Methods: In NSCLC cell lines A549 and H1650, the expression of ARRB1 was knocked down by transfection of siRNA or over-expressed by transfection of Flag-ARRB1 recombinant plasmids, which was verified by real-time fluorescent quantitative PCR and Western blotting. The effects of down-regulating and up-regulating ARRB1 expression on the transcription and secretion of interleukin-6 (IL-6) were detected by real-time fluorescent quantitative PCR and ELISA method, respectively. The interaction between ARRB1 and p300 was detected by protein immunocoprecipitation. The recruitment of p300 and the acetylation of histone in IL-6 promoter region after ARRB1 knock-down or overexpression were detected by chromatin immunocoprecipitation. The proliferation and apoptosis of ARRB1 silencing A549 cells were detected by CCK-8 assay and FCM, respectively. The expression and activation of IL-6/signal transducer and activator of transcription 3 (STAT3) signaling pathway-related molecules in ARRB1 silencing or overexpression NSCLC cells were investigated by Western blotting. Results: In ARRB1-silenced or overexpressed NSCLC cell lines A549 and H1650, ARRB1 enhanced the transcription and production of IL-6 (all P < 0.05). The interaction of ARRB1 and p300 was confirmed by forward and reverse immunocoprecipitation. After ARRB1 knockdown or overexpression, it was found that ARRB1 enhanced the recruitment of p300 in IL-6 promoter region (both P < 0.01) and increased the acetylating of IL-6 promoter (both P < 0.05). Moreover, ARRB1 could facilitate the growth (P < 0.01) and apoptosis inhibition of NSCLC cells. ARRB1 could promote the phosphorylation of STAT3 and the expressions of c-Myc and Bcl-2 proteins. Conclusion: In NSCLC cells, ARRB1 interacts with p300, facilitates the recruitment of p300 to IL-6 promoter, and up-regulates the acetylation of histone H3 and H4 in IL-6 promoter, leading to transcriptional activation of IL-6. So that ARRB1 positively regulates the activation of IL-6/STAT3 signaling through promoting the phosphorylation of STAT3 and the expressions of c-Myc and Bcl-2 proteins, contributing to the growth and anti-apoptosis of NSCLC cells.

Bone-edge electroacupuncture relieves pain by regulating expression of GRK5, β-arrestin 2 and PKCα proteins in locus coeruleus in bone cancer pain rats with morphine tolerance / 针刺研究

OBJECTIVE: To observe the effect of bone-edge electroacupuncture (EA) intervention on mechanical pain threshold (PT) and expression of G protein-coupled receptor kinase (GRK5), β-arrestin 2, total and phosphorylated PKC alpha (p-PKCα) proteins in the locus coeruleus (LC) of rats with bone cancer pain induced morphine tolerance, so as to reveal its partial central mechanisms underlying pain relief. METHODS: Forty SD rats were randomly divided into 5 groups, namely sham bone cancer, bone cancer pain, morphine tolerance, bone-edge EA, and sham EA (n＝ 8 rats in each group). The bone cancer with morphine tolerance model was established by intramedullary injection of MRMT-1 cells into the tibial cavity, and then intraperitoneal injection of morphine hydrochloride injection. After successful establishment of morphine tolerance model, the bone-edge EA (2 Hz/100 Hz，0.5－1.5 mA) was applied to bilateral "Zusanli" (ST36) and "Kunlun" (BL60) for 30 min, once a day for 7 days, after inserting the needle-tip to the tibial bone surface. The ipsilateral mechanical paw withdrawal thresholds (PWTs) were detected dynamically. The expression levels of GRK5, β-arrestin 2, PKCα and p-PKCα in the LC area were measured by Western blot. RESULTS: The PWTs of bone cancer pain rats were decreased on day 10 after inoculation of cancer cells (P0.05). The PWTs were significantly increased in the bone-edge EA intervention group (P0.05). In comparison with the sham bone cancer group, the expression of GRK5 protein in morphine tolerance group was significantly decreased (P<0.01); compared with morphine tolerance group, the expression of GRK5 protein in bone-edge EA group was increased(P<0.01). In comparison with the sham bone cancer group, the expression of β-arrestin 2 and p-PKCα in bone cancer group significantly increased (P<0.01). After the intervention, the increased β-arrestin 2 and p-PKCα expressions were reversed in the bone-edge EA group (P<0.01); compared with morphine tolerance group and sham EA group, the expression of PKCα protein was decreased(P<0.01). CONCLUSION: Bone-edge EA can effectively relieve morphine tolerance in bone cancer pain rats, which may be related to its functions in up-regulating GRK5 protein and down-regulating β-arrestin 2, PKCα and p-PKCα proteins in LC.　.

β-arrestin-2 inhibits autophagy by up-regulating PI3K/Akt signal to alleviate liver ischemia-reperfusion injury in mice / 器官移植

Objective To verify whether β-arrestin-2 inhibits autophagy by up-regulating PI3K/Akt signal to protect the liver from ischemia-reperfusion injury (IRI) in mice. Methods Twelve β-arrestin-2 knockout (KO) and twelve wild-type (WT) C57BL/6 mice were randomly divided into the KO+sham group, KO+IRI group, WT+sham group and WT+IRI group, six mice in each group. The mouse models with 70% liver IRI were established or sham operation was performed. Relevant experiments were carried out at 6 h after liver reperfusion or operation. The expression levels of apoptosis signal protein cleaved Caspase-3, proliferation signal protein Ki-67 and the PI3K/Akt signal protein p-Akt were detected by immunohistochemical staining. Results Immunohistochemical staining demonstrated that compared with the corresponding sham group, the positive cell count for cleaved Caspase-3, Ki-67 and p-Akt in liver tissues of mice was significantly increased in the KO+IRI and WT+IRI groups (all P < 0.01). Compared with the WT+IRI group, the positive cell count for cleaved Caspase-3 in liver tissues of mice was significantly increased, whereas the positive cell count forKi-67 and p-Akt was significantly decreased in the KO+IRI group (both P < 0.05). Conclusions β-arrestin-2 can mitigate the liver cell apoptosis and promote the repair of injury after IRI in mice. Moreover, β-arrestin-2 inhibits autophagy by up-regulating the PI3K/Akt signal to alleviate liver IRI in mice.

β-arrestin1 overexpression suppresses progression of human T-cell acute lymphatic leukemia Molt-4 cell xenograft in mice / 南方医科大学学报

OBJECTIVE@#To investigate the effect of β-arrestin1 overexpression on tumor progression in a NCG mouse model bearing T-cell acute lymphocytic leukemia (T-ALL) Molt-4 cell xenograft.@*METHODS@#Molt-4 cells were tagged with firefly-luciferase (F-Luc) by lentiviral infection, and fluorescence intensity of the cells was detected using a luminescence detector. Molt-4 cell lines with β-arrestin1 overexpression or knockdown were constructed by lentivirus infection and injected the tail vein in sub-lethal irradiated NCG mice. Body weight changes and survival time of the xenografted mice were observed, and the progression of T-ALL in the mice was evaluated using an fluorescence imaging system. Sixteen days after xenografting, the mice were euthanatized and tumor cell infiltration was observed in the slices of the liver and spleen.@*RESULTS@#We successfully tagged Molt-4 cells with F-Luc and overexpressed or knocked down β-arrestin1 in the tagged cells. Bioluminescent imaging showed obvious luminescence catalyzed by F-Luc in Molt-4 cells. After injection of Molt-4-Luc cells into irradiated NCG mice, a gradual enhancement of luminescence in the xenografted mice was observed over time, while the body weight of the mice decreased. Compared with the control mice, the mice xenografted with β-arrestin1-overexpressing Molt-4 cells had significantly prolonged survival time ( < 0.001), while the survival time of the mice xenografted with Molt-4 cells with β- arrestin1 knockdown was significantly shortened ( < 0.001). Histological examination revealed fewer infiltrating tumor cells in the liver and spleen of the mice xenografted with β-arrestin1-overexpressing Molt-4 cells in comparison with the mice bearing parental Molt-4 cell xenografts.@*CONCLUSIONS@#β-arrestin1 overexpression suppresses tumor progression in mice bearing Molt-4 cell xenograft.

Mechanisms of β-arrestin-biased GPCR signal transduction and advances in drug research / 药学学报

G protein-coupled receptors (GPCR) are a class of receptor superfamily that exist on the surface of cell membrane. With the intensive studies on the GPCR desensitization regulator—β-arrestins, it is found that activated GPCR can not only conduct signal transduction through G protein-dependent pathway, but also mediate via non-G protein-dependent pathway. In addition to mediate endocytosis and desensitization, β-arrestins also initiate a new series of signal transduction events. Therefore, the concept of "biased transduction" was put forward: the receptor activated by a specific ligand could selectively activate a specific signaling pathway, leading the signal to be transmitted downstream along a "preferential" pathway. We call the ligand that binds to the receptor and causes biased activation "biased ligand". It is generally believed that the phenomenon of bias results from different binding modes of ligands and receptors, including multiple receptor conformations, diverse sites that downstream signal proteins bind, and signal proteins’ own conformations, etc. Here we give a brief review focusing on the mechanisms of β-arrestin-biased GPCR signal transduction and the advances in the drug development on β-arrestin biased ligands.

β-arrestin2 promoting mice colitis through impairment of epithelial barrier function / 实用医学杂志

Objective To investigate the role of β-arrestin2 in intestinal inflammation and illustrate the mechanisms from the perspective of epithelial barrier function. Methods Dextran sodium sulfate(DSS)is used to induce acute intestinal colitis in mice. The experiment groups are designed as the wild type control(WT),the wild type colitis (WT+DSS) and the β-arrestin2- knockout colitis (KO+DSS). The expression of β-arrestin2 gene by mRNA and protein level is compared between the WT and WT + DSS groups. The difference of weight loss , disease activity index(DAI),spleen weight,colon length,histological score,intestinal permeability and important tight junction proteins (occludin ,claudin1 and ZO-1) were detected in the WT+DSS and KO+DSS groups. Results Compared with the WT group,the expression of β-arrestin2 was significantly higher in the colon of the WT+DSS group. Compared with the WT+DSS group,the KO+DSS group had less weight loss(P < 0.05),lower DAI(P<0.05),smaller spleen,longer colon and lower histological score(P=0.002). The KO+DSS group had a lower intestinal permeability(P = 0.009)and higher protein level of occludin and claudin1.There was no signifi-cant difference of ZO-1 in the two groups. Conclusion β-arrestin2 may promote mouse colitis through impairment of epithelial barrier function.

Role of M3 receptor in the effect of penehyclidine hydrochloride up-regulating β-arrestin-1 expression / 重庆医学

Objective To investigate the role of M3 receptor in the effect of penehyclidine hydrochloride(PHC) upregulating β-arrestin-1 expression in lipopolysaccharide(LPS)-induced human pulmonary microvascular endothelial cell(HPMVEC) injury.Methods.M3 shRNA transfected HPMVEC and normal HPMVEC cells were randomly divided into LPS group(A),LPS+pHC group(B),LPS+ M3 shRNA transfection group(C) and PHC+ LPS+ M3 shRNA transfection group(D).The cytoskeleton change was observed by laser scanning confocal.The LDH level in cellular supernate was detected.The VCAM 1 protein expression was examined by immunofluorescence chemistry.β-arrestin-1 protein expression was determined by Western blot and β-arrestin-1mRNA expression was measured by real-time PCR.Results Compared with the group A or C,F-actin cytoskeleton arrangement in the group B or D was neat,the LDH level and VCAM-1 protein expression were decreased,and β-arrestin-1 expression was increased;compared with group A or B,F-actin cytoskeleton arrangement in the group C or D was neat,the LDH level and VCAM-1 protein expression were decreased,while the β-arrestin-1 expression had no obvious change.Conclusion Silence M3 receptor is conducive to reduce LPS-induced HPMVEC injury.But the role of PHC up-regulating β-arrestin-1 expression has no necessary connection with M3 receptor.

Biased G Protein-Coupled Receptor Signaling: New Player in Modulating Physiology and Pathology

G protein-coupled receptors (GPCRs) are a family of cell-surface proteins that play critical roles in regulating a variety of pathophysiological processes and thus are targeted by almost a third of currently available therapeutics. It was originally thought that GPCRs convert extracellular stimuli into intracellular signals through activating G proteins, whereas β-arrestins have important roles in internalization and desensitization of the receptor. Over the past decade, several novel functional aspects of β-arrestins in regulating GPCR signaling have been discovered. These previously unanticipated roles of β-arrestins to act as signal transducers and mediators of G protein-independent signaling have led to the concept of biased agonism. Biased GPCR ligands are able to engage with their target receptors in a manner that preferentially activates only G protein- or β-arrestin-mediated downstream signaling. This offers the potential for next generation drugs with high selectivity to therapeutically relevant GPCR signaling pathways. In this review, we provide a summary of the recent studies highlighting G protein- or β-arrestin-biased GPCR signaling and the effects of biased ligands on disease pathogenesis and regulation.

Molecular Signature That Determines the Acute Tolerance of G Protein-Coupled Receptors

Desensitization and acute tolerance are terms used to describe the attenuation of receptor responsiveness by prolonged or intermittent exposure to an agonist. Unlike desensitization of G protein-coupled receptors (GPCRs), which is commonly explained by steric hindrance caused by the β-arrestins that are translocated to the activated receptors, molecular mechanisms involved in the acute tolerance of GPCRs remain unclear. Our studies with several GPCRs and related mutants showed that the acute tolerance of GPCRs could occur independently of agonist-induced β-arrestin translocation. A series of co-immunoprecipitation experiments revealed a correlation between receptor tolerance and interactions among receptors, β-arrestin2, and Gβγ. Gβγ displayed a stable interaction with receptors and β-arrestin2 in cells expressing GPCRs that were prone to undergo tolerance compared to the GPCRs that were resistant to acute tolerance. Strengthening the interaction between Gβγ and β-arrestin rendered the GPCRs to acquire the tendency of acute tolerance. Overall, stable interaction between the receptor and Gβγ complex is required for the formation of a complex with β-arrestin, and determines the potential of a particular GPCR to undergo acute tolerance. Rather than turning off the signal, β-arrestins seem to contribute on continuous signaling when they are in the context of complex with receptor and Gβγ.

The changes of β-arrestin 2 and microtubule-associated protein light chain 3 in renal tissue of rats with renal ischemia reperfusion injury / 中国小儿急救医学

Objective To investigate the expression of β-arrestin2 and microtubule-associated pro-tein light chain(LC)3 in renal of rat with acute renal ischemia reperfusion injury,and to analyze the relation-ship between them and renal injury. Methods Fifty-four male SD rat(3-4 weeks old) were randomly divid-ed into three groups:control group,sham group,acute ischemic reperfusion injury group. We established the acute renal ischemia reperfusion injury model through removing the right kidney and clamping the left renal for 45 minutes with noninvasive arterial clip. We obtained the kidney and blood samples respectively at 12 h, 24 h,36 h,48 h,72 h,96 h after the surgery. Expressions ofβ-arrestin2 and LC3 protein were detected by the immunohistochemistry method and Western blot method. The renal function and morphological changes were assessed. Results Compared with control group and sham group,the serum creatinine and kidney pathologi-cal grading of acute ischemia reperfusion injury group obviously rised. The kidney injury was the most serious at the 24 h after acute ischemic reperfusion injury. The expressions of β-arrestin2 and LC3 were little in the control group and sham group. However,the expressions of these two indicators were obviously higher and reached the peak at the 12 h after acute ischemia reperfusion injury. All these results suggested that the chan-ges of these two indicators were anterior to the histopathological changes. The expressions ofβ-arrestin 2 and LC3 protein were in positive correlation with the kidney injury(r=0. 821,P<0. 05;r=0. 913,P<0. 05). Conclusion In the acute renal ischemia-reperfusion injury,β-arrestin2 may be as a kind of upstream regula-tory protein involving in the kidney pathological process through the regulation of the autophagy.

β-arrestin1 promotes leukemia cell K562 migration and invasion by activating STAT3 signaling pathway / 中国免疫学杂志

Objective:To investigate the function of β-arrestin1 and its related mechanisms in migration and invasion capacity of leukemia cell K562. Methods:β-arrestin1-siRNA or negative siRNA was transfected into K562 cells of experiment group or control group. The migration and invasion capacity of K562 cells was detected by transwell tests;and the protein expression of β-arrestin1 and pSTAT3 were detected by Western blot. Results:As compared to control group and negative siRNA group,the migration and invasion capacity of transfected β-arrestin1-siRNA group were attenuated about 43% or 52% ( P<0. 05 );Western blot showed that the expression of phosphorylation of STAT3 was decreased inβ-arrestin1-siRNA group. And the STAT3 inhibitors obviously suppressed the migration and invasion capacity of K562 cells. Conclusion:In leukemia cells K562,β-arrestin1 activates STAT3 signaling pathway to promote the cell migration and invasion.

Roles of Dopamine D₂ Receptor Subregions in Interactions with β-Arrestin2

β-Arrestins are one of the protein families that interact with G protein-coupled receptors (GPCRs). The roles of β-arrestins are multifaceted, as they mediate different processes including receptor desensitization, endocytosis, and G protein-independent signaling. Thus, determining the GPCR regions involved in the interactions with β-arrestins would be a preliminary step in understanding the molecular mechanisms involved in the selective direction of each function. In the current study, we determined the roles of the N-terminus, intracellular loops, and C-terminal tail of a representative GPCR in the interaction with β-arrestin2. For this, we employed dopamine D₂ and D₃ receptors (D₂R and D₃R, respectively), since they display distinct agonist-induced interactions with β-arrestins. Our results showed that the second and third intracellular loops of D₂R are involved in the agonist-induced translocation of β-arrestins toward plasma membranes. In contrast, the N- and C-termini of D₂R exerted negative effects on the basal interaction with β-arrestins.

Type Ⅲ TGF-βreceptor mediated signaling pathway and its role in fibrotic diseases / 中国药理学通报

Transforming growth factor β(TGF-β)superfamily ligands play an important role in regulating cellular homeostasis including proliferation,differentiation,apoptosis,immune sur-veillance and angiogenesis.Type Ⅲ TGF-βreceptor (TβRⅢ) is considered to be the coreceptor of TGF-βsuperfamily.TβRⅢnot only has an effect on classical Smad signaling pathway,but also on non-Smad signaling pathway.TβRⅢplays a crucial role in fibrosis,tumor,cardiovascular diseases via mediating kinds of signaling pathways.This paper reviews TβRⅢ mediated sig-naling pathway and its role in fibrotic diseases.

Correlation of CCR5 expression with β-arrestin 2 expression in colonic mucosa of patients with inflammatory bowel disease / 中国病理生理杂志

AIM:To analyze the expression of CCR5 and correlation with the expression ofβ-arrestin 2 in the intestinal mucosa of the patients with inflammatory bowel disease ( IBD) , so as to study the role of CCR5 andβ-arrestin 2 in the pathogenesis of IBD.METHODS:Paraffin sections of the colonic mucosa were prepared from 53 patients with active IBD, 26 patients with remissive IBD and 30 healthy people.Immunohistochemical EnVision two-step method was used to test the expression of CCR5 andβ-arrestin 2 in the biopsic intestinal mucosa.RESULTS:The positive rate, strongly posi-tive rate and immunohistochemical score of CCR5 expression in active IBD were significantly higher than those in normal controls or remissive IBD (P<0.05).No correlation of CCR5 expression with clinical severity, lesion distribution, and endoscopic grade in active IBD was observed.The expression ofβ-arrestin 2 was significantly lower in active IBD than that in the remissive IBD and normal controls, and there was a negative correlation ofβ-arrestin 2 expression with CCR5 expres-sion (P<0.05).CONCLUSION:The expression of CCR5 is higher, and expression ofβ-arrestin 2 is lower, and there is a negative correlation of expression of CCR5 with expression ofβ-arrestin 2 in intestinal mucosa of the active IBD.

β-arrestin-2 alleviates mouse hepatic ischemia-reperfusion injury by inhibiting autophagy / 器官移植

Objective To investigate the impact of β-arrestin-2 on hepatic autophagy after ischemia-reperfusion (IR)and its effect on mouse hepatic ischemia-reperfusion injury (IRI).Methods β-arrestin-2 wild type (WT)and knock out (KO)mice were used to build a mouse model of hepatic IR (70% hepatic warm ischemia for 90 min).Mice were divided into four groups:WT mice sham-operated group (WT +Sham group),WT mice IR group (WT +IR group),KO mice sham-operated group (KO +Sham group)and KO mice IR group (KO +IR group),18 mice in each group.Serum and liver tissues were collected at 6,12 and 24 h after reperfusion.The alanine aminotransferase (ALT),aspartate aminotransferase (AST)measurement and liver tissues hematoxylin-eosin (HE)staining and pathology analysis were used to estimate hepatic injury. The expression of light chain (LC)3,the key protein of autophagy,were detected by immunohistochemical (IHC)staining and western blot.Autophagosomes in liver tissues were evaluated by transmission electron microscopy (TEM).Results Compared with Sham groups,the levels of serum ALT and AST significantly increased in IR groups at each time point (all in P <0.01).The levels of KO +IR group were higher than those of WT +IR group at each time point (all in P <0.01).The result of liver tissue HE staining showed that liver cell morphology and lobular architecture was normal in WT +Sham group and KO +Sham group at each time point after reperfusion.Liver cells were light or moderate swelling with liver sinus expansion in KO +IR group and WT +IR group at 6 h after reperfusion.And liver cells were severe swelling with inflammatory cells infiltration,and flake damage area is obvious at 12 h after reperfusion.Liver rope arranged regularly at 24 h after reperfusion.The degree of hepatic injury in KO +IR group was more serious than WT +IR group.IHC staining and western blot analysis showed that the expression levels of LC3 increased in IR groups at 6,12 h but slightly decreased at 24 h after reperfusion.And the expression levels of KO +IR group were higher than WT +IR group.TEMresult show that autophagosomes in IR groups were obviously more than those in Sham groups (both in P <0.01).The counts of autophagosomes in KO +IR group were more than those of WT +IR group (P <0.05).Conclusions β-arrestin-2 may alleviate mouse hepatic IRI by inhibiting autophagy.