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.

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

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-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.

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.

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.