Abstract P279: YAP, a Transcriptional Cofactor of the Hippo Pathway, Regulates Cardiomyocyte Growth, Survival, and Proliferation

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Yanfei Yang ◽  
Noritsugu Nakano ◽  
Junichi Sadoshima
Keyword(s):  
Cardiac Hypertrophy ◽  
Hippo Pathway ◽  
Neonatal Rat ◽  
Border Zone ◽  
Luciferase Reporter ◽  
Tunel Staining ◽  
H2o2 Treatment ◽  
Rat Hearts ◽  
The Hippo Pathway

Mst1 and Lats2, components of the mammalian Hippo pathway, stimulate apoptosis and inhibit hypertrophy of cardiomyocytes (CMs), thereby mediating reperfusion injury and heart failure. YAP, a transcription factor co-factor, is negatively regulated by the Hippo pathway, and controls cell survival, proliferation and tissue regeneration. The role of YAP in regulating growth and death of CMs is poorly understood. YAP overexpression in CMs induced cardiac hypertrophy, as indicated by increases in cell size (+1.2 fold, p<0.01), protein content (+1.1 fold, p<0.01) and ANF (luciferase reporter activity +1.7 fold, mRNA +2.2 fold, and staining +2.7 fold, p<0.01). Lats2 phosphorylates YAP at Serine 127, which induces cytoplasmic translocation of YAP, whereas YAP(S127A) is localized constitutively in the nucleus. Expression of YAP(S127A) enhanced hypertrophy in cultured CMs compared to that of wild type YAP (+1.87 fold ANF staining, p<0.05), suggesting that the Mst1/Hippo pathway negatively regulates cardiac hypertrophy through YAP. YAP inhibited cell death induced by H2O2 treatment, as evaluated with TUNEL staining (-65%, p<0.05) and CellTiter Blue assays (+34.9%, p<0.01), indicating that YAP plays an essential role in mediating CM survival. Interestingly, YAP also significantly increased Ki67 positive cells in cultured CMs compared to LacZ (+2.65 fold, p<0.05). We used a mouse model of chronic myocardial infarction (MI) to evaluate the function of YAP in the heart in vivo. Although YAP is diffusely localized both in the nucleus and cytosol in CMs in control hearts, CMs in the border zone of MI exhibited nuclear localization of YAP whereas YAP was excluded from the nucleus in CMs in the remodeling area four days after MI (+6.52 fold and +1.28 fold). Some of the YAP positive CMs in the border zone exhibited positive co-staining with Ki67, suggesting that YAP potentially induces CM proliferation. A significant increase in nuclear YAP and Ki67 positive CMs (+2.95 fold, p<0.01 and +2.18 fold, p<0.05) was also observed in neonatal rat hearts whose apex was surgically resected three days before euthanasia. These results suggest that YAP plays an important role in mediating not only hypertrophy and survival, but also proliferation of CMs in response to myocardial injury.

Abstract 51: Aldosterone Induces Cardiac Deleterious Effects Through A Grk2 And Grk5 Dependent Pathway

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Alessandro Cannavo ◽  
Daniela Liccardo ◽  
Sarah M Bass ◽  
Benjamin Woodall ◽  
Christopher J Traynham ◽  
...  
Keyword(s):  
Cell Death ◽  
Cardiac Hypertrophy ◽  
Cardiac Fibrosis ◽  
Neonatal Rat ◽  
Tunel Staining ◽  
Ros Generation ◽  
Angiotensin Ii Receptor ◽  
Time Data ◽  
Pre Treatment

High Aldosterone (Aldo) plasma levels are present in heart failure patients and are associated with increased cardiac fibrosis and hypertrophy. These effects have been shown to be, in part, related to the transactivation of the angiotensin II receptor (AT1R), a G-protein coupled receptor (GPCR). In this regard, the GPCR kinase 2 (GRK2) and 5 (GRK5) are both critical regulators of cardiac function through GPCR regulation. Since these GRKs have also been shown to play a role in cardiac hypertrophy and HF development we investigated whether these kinases may play a role in myocardial Aldo signaling. To test this, we first treated neonatal rat ventricular cardiomyocytes (NRVMs) with Aldo (1 μM) and looked for GRK regulation. Following 12 hrs of Aldo-stimulation we observed a significant increase in both GRK2 and GRK5 protein levels. We also found that Aldo induced the localization of GRK2 to mitochondria, which the lab has previously found to occur following ischemic injury leading to increased cell death and mitochondrial dysfuntion. Indeed, high Aldo on NRVMs led to a significant increase in ROS generation and cell death, as observed by Mitosox Red and TUNEL staining, respectively. Notably, all these effects were abolished respectively by Spironolactone (Spiro, an Aldo receptor blocker) or Losartan (Los, an AT1R antagonist) pre-treatment. Next, in nuclear fractions, purified from Aldo-treated NRVMs, we observed a consistent increase in GRK5 nuclear localization that consequently induced a significant activation of hypertrophic genes, which is consistent with previous studies showing GRK5 being a key regulator of maladaptive cardiac hypertrophy after pressure-overload. Importantly, Spiro pre-treatment efficiently abolished these effects of GRK5. Finally, we treated wild-type mice in vivo with Aldo for two and four weeks and not only found that this induced significant cardiac hypertrophy and fibrosis compared to saline-treated mice, we also found significant increases in levels of GRK2 and GRK5. Therefore, our study provide, for the first time, data demonstrating that GRK2 and GRK5 are potential regulators of Aldo-mediated cardiac pathology acting either down-stream of mineralocorticoid receptor or transactivated AT1Rs.

scholarly journals Hippo-YAP/MCP-1 mediated tubular maladaptive repair promote inflammation in renal failed recovery after ischemic AKI

2021 ◽  
Vol 12 (8) ◽  
Author(s):  
Zhihuang Zheng ◽  
Chuanlei Li ◽  
Guangze Shao ◽  
Jinqing Li ◽  
Kexin Xu ◽  
...  
Keyword(s):  
Chronic Inflammation ◽  
Ischemia Reperfusion ◽  
Hippo Pathway ◽  
Glucose Deprivation ◽  
Macrophage Infiltration ◽  
Renal Inflammation ◽  
Monocyte Chemoattractant Protein 1 ◽  
The Hippo Pathway

AbstractAcute kidney injury (AKI) is associated with significant morbidity and its chronic inflammation contributes to subsequent chronic kidney disease (CKD) development. Yes-associated protein (YAP), the major transcriptional coactivator of the Hippo pathway, has been shown associated with chronic inflammation, but its role and mechanism in AKI-CKD transition remain unclear. Here we aimed to investigate the role of YAP in AKI-induced chronic inflammation. Renal ischemia/reperfusion (I/R) was used to induce a mouse model of AKI-CKD transition. We used verteporfin (VP), a pharmacological inhibitor of YAP, to treat post-IRI mice for a period, and evaluated the influence of YAP inhibition on long-term outcomes of AKI. In our results, severe IRI led to maladaptive tubular repair, macrophages infiltration, and progressive fibrosis. Following AKI, the Hippo pathway was found significantly altered with YAP persistent activation. Besides, tubular YAP activation was associated with the maladaptive repair, also correlated with interstitial macrophage infiltration. Monocyte chemoattractant protein 1 (MCP-1) was found notably upregulated with YAP activation. Of note, pharmacological inhibition of YAP in vivo attenuated renal inflammation, including macrophage infiltration and MCP-1 overexpression. Consistently, in vitro oxygen-glucose deprivation and reoxygenation (OGD/R) induced YAP activation and MCP-1 overproduction whereas these could be inhibited by VP. In addition, we modulated YAP activity by RNA interference, which further confirmed YAP activation enhances MCP-1 expression. Together, we concluded tubular YAP activation with maladaptive repair exacerbates renal inflammation probably via promoting MCP-1 production, which contributes to AKI-CKD transition.

Abstract 214: MicroRNA-451 Aggravates Lipotoxic Cardiomyopathy Through Suppression of the LKB1/AMPK Signaling Pathway

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Yasuhide Kuwabara ◽  
Takahiro Horie ◽  
Osamu Baba ◽  
Toru Kita ◽  
Takeshi Kimura ◽  
...  
Keyword(s):  
Cardiac Hypertrophy ◽  
Diabetic Cardiomyopathy ◽  
Calcium Binding ◽  
Saturated Fatty Acids ◽  
Mammalian Target Of Rapamycin ◽  
Neonatal Rat ◽  
Albumin Concentration ◽  
Dependent Manner ◽  
Ceramide Level

Rationale: In some type 2 diabetes mellitus (T2D) patients without hypertension, cardiac hypertrophy and attenuated cardiac function are observed, and this insult is termed “diabetic cardiomyopathy.” Tons of evidence suggests that microRNAs are involved in cardiac diseases. However, the functions of microRNAs in the diabetic cardiomyopathy induced by T2D and obesity are not fully understood. Methods and Results: C57BL/6 mice were fed a high-fat diet (HFD) for 20 weeks, which induced obesity and T2D. MicroRNA microarray and real-time PCR revealed that miR-451 levels were significantly increased in the T2D mouse hearts (n=4-5, p<0.05). Because excess supply of saturated fatty acids is a cause of diabetic cardiomyopathy, we stimulated neonatal rat cardiac myocytes (NRCMs) with palmitate in physiological albumin concentration and confirmed that miR-451 expression was increased in a dose-dependent manner (n=6-12, p<0.01). Loss of miR-451 function ameliorated palmitate-induced lipotoxicity in NRCMs (n=4, p<0.05). Calcium-binding protein 39 (Cab39) is a scaffold protein of liver kinase B1 (LKB1), an upstream kinase of AMP-activated protein kinase (AMPK). Cab39 was a direct target of miR-451 in NRCMs and Cab39 overexpression rescued the palmitate-induced lipotoxicity in NRCMs (n=4, p<0.01). To clarify miR-451 functions in vivo, we generated cardiomyocyte-specific miR-451 knockout (cKO) mice. HFD-induced cardiac hypertrophy and contractile reserves were ameliorated in cKO mice compared with HFD-fed control mice. Protein levels of Cab39 and phosphorylated AMPK were increased and phosphorylated mammalian target of rapamycin (mTOR) was reduced in HFD-fed cKO mouse hearts compared with HFD-fed control mouse hearts (n=10-12, p<0.05). We also measured the lipotoxic intermediates, triglyceride and ceramide, in these mouse hearts using HPLC-evaporative light scattering detector (ELSD). Although there was no difference in triglyceride levels (n=3-5), ceramide level was decreased in HFD-fed cKO mice compared with HFD-fed control mice (n=3-5, p<0.05). Conclusions: Our results indicate that miR-451 exacerbates diabetic cardiomyopathy. miR-451 is a potential therapeutic target for cardiac disease caused by T2D and obesity.

scholarly journals LncRNA SNHG12 regulates the radiosensitivity of cervical cancer through the miR-148a/CDK1 pathway

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Chen Wang ◽  
Shiqing Shao ◽  
Li Deng ◽  
Shelian Wang ◽  
Yongyan Zhang
Keyword(s):  
Cell Cycle ◽  
Cervical Cancer ◽  
Tumor Growth ◽  
Luciferase Reporter ◽  
Tunel Staining ◽  
Cell Cycle Distribution ◽  
Ki 67 ◽  
In Vivo Experiments ◽  
Potential Biomarker

Abstract Background Radiation resistance is a major obstacle to the prognosis of cervical cancer (CC) patients. Many studies have confirmed that long non-coding RNAs (lncRNAs) are involved in the regulation of radiosensitivity of cancers. However, whether small nucleolar RNA host gene 12 (SNHG12) regulates the radiosensitivity of CC remains unknown. Methods Quantitative real-time polymerase chain reaction was used to measure the expression levels of SNHG12 and microRNA-148a (miR-148a). The radiosensitivity of cells was evaluated by clonogenic assay. Flow cytometry and caspase-3 activity assay were performed to assess the apoptosis ability and cell cycle distribution of cells. Besides, dual-luciferase reporter and RNA immunoprecipitation assay were used to verify the interaction between miR-148a and SNHG12 or cyclin-dependent kinase 1 (CDK1). Also, the protein levels of CDK1, CCND1 and γ-H2AX were detected by western blot analysis. Furthermore, in vivo experiments were conducted to verify the effect of SNHG12 on CC tumor growth. Ki-67 and TUNEL staining were employed to evaluate the proliferation and apoptosis rates in vivo. The hematoxylin and eosin (HE) staining were employed to evaluate the tumor cell morphology. Results SNHG12 was upregulated in CC tissues and cells, and its knockdown improved the radiosensitivity by promoting the radiation-induced apoptosis and cell cycle arrest of CC cells. Also, miR-148a could be sponged by SNHG12 and could target CDK1. MiR-148a inhibitor or CDK1 overexpression could invert the promotion effect of silenced-SNHG12 on CC radiosensitivity. Meanwhile, SNHG12 interference reduced the tumor growth of CC, increased miR-148a expression, and inhibited CDK1 level in vivo. Conclusion LncRNA SNHG12 promoted CDK1 expression to regulate the sensitivity of CC cells to radiation through sponging miR-148a, indicating that SNHG12 could be used as a potential biomarker to treat the radiotherapy resistance of CC patients.

scholarly journals MiR-22-3p suppresses sepsis-induced acute kidney injury by targeting PTEN

2020 ◽  
Vol 40 (6) ◽  
Author(s):  
Xudong Wang ◽  
Yali Wang ◽  
Mingjian Kong ◽  
Jianping Yang
Keyword(s):  
Acute Kidney Injury ◽  
Inflammatory Response ◽  
Periodic Acid ◽  
Kidney Injury ◽  
Luciferase Reporter ◽  
Tunel Staining ◽  
Tnf Α

Abstract Background: Septic acute kidney injury is considered as a severe and frequent complication that occurs during sepsis. The present study was performed to understand the role of miR-22-3p and its underlying mechanism in sepsis-induced acute kidney injury. Methods: Rats were injected with adenovirus carrying miR-22-3p or miR-NC in the caudal vein before cecal ligation. Meanwhile, HK-2 cells were transfected with the above adenovirus following LPS stimulation. We measured the markers of renal injury (blood urea nitrogen (BUN), serum creatinine (SCR)). Histological changes in kidney tissues were examined by hematoxylin and eosin (H&E), Masson staining, periodic acid Schiff staining and TUNEL staining. The levels of IL-1β, IL-6, TNF-α and NO were determined by ELISA assay. Using TargetScan prediction and luciferase reporter assay, we predicted and validated the association between PTEN and miR-22-3p. Results: Our data showed that miR-22-3p was significantly down-regulated in a rat model of sepsis-induced acute kidney injury, in vivo and LPS-induced sepsis model in HK-2 cells, in vitro. Overexpression of miR-22-3p remarkably suppressed the inflammatory response and apoptosis via down-regulating HMGB1, p-p65, TLR4 and pro-inflammatory factors (IL-1β, IL-6, TNF-α and NO), both in vivo and in vitro. Moreover, PTEN was identified as a target of miR-22-3p. Furthermore, PTEN knockdown augmented, while overexpression reversed the suppressive role of miR-22-3p in LPS-induced inflammatory response. Conclusions: Our results showed that miR-22-3p induced protective role in sepsis-induced acute kidney injury may rely on the repression of PTEN.

Methylation of the hippo signalling effector YAP by SETD7 drives myocardial ischemic injury

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
S Ambrosini ◽  
F Montecucco ◽  
A Akhmedov ◽  
S.A Mohammed ◽  
P Brown ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Infarct Size ◽  
Hippo Pathway ◽  
Neonatal Rat ◽  
Doppler Imaging ◽  
Coronary Artery Ligation ◽  
Physical Interaction ◽  
Funding Source ◽  
Gene Promoters ◽  
The Hippo Pathway

Abstract Introduction Myocardial ischemia/reperfusion (I/R) injury is one of the most deleterious cardiovascular conditions and a leading cause of mortality. The Hippo pathway effector YAP critically regulates cardiomyocyte proliferation and survival during myocardial I/R injury. However, the mechanisms regulating YAP activation in this setting remain poorly understood. Post-translational modifications of proteins, namely methylation, modulate pathways implicated in myocardial I/R injury. The methyltransferase SETD7 is emerging as a regulator of cell survival via methylation of histone and non-histone proteins. Whether SETD7 participates to myocardial I/R injury remains elusive. Purpose To investigate the role of SETD7 in regulating Hippo signaling during myocardial I/R injury. Methods Neonatal rat ventricular myocytes (NRVM) were exposed to normal glucose levels or glucose deprivation (GD) for 15 h, in the presence of the selective SETD7 inhibitor [(R)-PFI-2] or its inactive enantiomer [(S)-PFI-2]. Western blot and real time PCR were employed to investigate the effects of energy stress on SETD7 and the Hippo pathway, while apoptosis was assessed by Caspase-3 activity assay. YAP activity was assessed through chromatin immunoprecipitation assay (ChIP), its localization was examined by confocal microscopy while mono-methylation was assessed by immunoblotting. SETD7 knockout (SETD7−/−) mice and wild-type (WT) littermates (male, 8–12 weeks old) underwent 1 h of left anterior descending (LAD) coronary artery ligation followed by 24 h of reperfusion. Infarct size was assessed by TTC staining and shown as infarct size per ventricle surface (I/V). Cardiac function was investigated at 24h by conventional and Tissue Doppler Imaging (TDI) echocardiography. Results GD in NRVMs led to upregulation of SETD7 and physical interaction with the pro-survival transcriptional cofactor YAP, resulting in its direct mono-methylation. Furthermore SETD7-dependent methylation of YAP led to its cytosolic retention and subsequent reduction of YAP binding to the promoter of pro-survival genes. Of note, pharmacological inhibition of SETD7 by (R)-PFI-2 blunted YAP mono-methylation while restoring its nuclear retention. Mechanistically, SETD7 inhibition promoted YAP binding to catalase and superoxide dismutase (SOD) gene promoters, thus preventing GD-induced mitochondrial oxidative stress and apoptosis. In line with our in vitro findings, SETD7−/− mice showed decreased infarct size as compared to WT littermates and preserved cardiac systolic (ejection fraction, fractional shortening) and diastolic function, as assessed by both conventional and TDI echocardiography. Conclusions We show that SETD7-dependent methylation of YAP is required for its inactivation, thus leading to myocyte oxidative stress and apoptosis. Pharmacological modulation of SETD7 by (R)-PFI-2 may represent a new therapeutic approach to prevent myocardial ischemic damage through modulation of the Hippo pathway. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): Swiss Heart Foundation

MicroRNA-183 as a Novel Regulator Protects Against Cardiomyocytes Hypertrophy via Targeting TIAM1

2020 ◽  
Author(s):  
Fu-han Gong ◽  
Xi-Lu Chen ◽  
Quan Zhang ◽  
Xiao-qiang Xiao ◽  
Yong-sheng Yang ◽  
...  
Keyword(s):  
Cardiac Hypertrophy ◽  
Bioinformatics Analysis ◽  
Negative Control ◽  
Neonatal Rat ◽  
Luciferase Reporter ◽  
Ang Ii ◽  
Direct Target Gene ◽  
Phenotype Analysis ◽  
Reporter Assays

Abstract BACKGROUND MicroRNAs serve as important regulators of the pathogenesis of cardiac hypertrophy. Among them, miR-183 is well documented as a novel tumor suppressor in previous studies, whereas it exhibits a downregulated expression in cardiac hypertrophy recently. The present study was aimed to examine the effect of miR-183 on cardiomyocytes hypertrophy. METHODS Angiotensin II (Ang II) was used for establishment of cardiac hypertrophy model in vitro. Neonatal rat ventricular cardiomyocytes transfected with miR-183 mimic or negative control were further utilized for the phenotype analysis. Moreover, the bioinformatics analysis and luciferase reporter assays were used for exploring the potential target of miR-183 in cardiomyocytes. RESULTS We observed a significant decreased expression of miR-183 in hypertrophic cardiomyocytes. Overexpression of miR-183 significantly attenuated the cardiomyocytes size morphologically and prohypertrophic genes expression. Moreover, we demonstrated that TIAM1 was a direct target gene of miR-183 verified by bioinformatics analysis and luciferase reporter assays, which showed a decreased mRNA and protein expression in the cardiomyocytes transfected with miR-183 upon Ang II stimulation. Additionally, the downregulated TIAM1 expression was required for the attenuated effect of miR-183 on cardiomyocytes hypertrophy. CONCLUSIONS Taken together, these evidences indicated that miR-183 acted as a cardioprotective regulator for the development of cardiomyocytes hypertrophy via directly regulation of TIAM1.

scholarly journals A Drosophila model of oral peptide therapeutics for adult intestinal stem cell tumors

2020 ◽  
Vol 13 (7) ◽  
pp. dmm044420 ◽  
Author(s):  
Anjali Bajpai ◽  
Taushif Ahmad Quazi ◽  
Hong-Wen Tang ◽  
Nishat Manzar ◽  
Virender Singh ◽  
...  
Keyword(s):  
Stem Cell ◽  
Hippo Pathway ◽  
Intestinal Stem Cell ◽  
Peptide Therapeutics ◽  
Small Molecule Drugs ◽  
Drosophila Model ◽  
Therapeutic Peptides ◽  
Oral Therapeutic ◽  
The Hippo Pathway

ABSTRACTPeptide therapeutics, unlike small-molecule drugs, display crucial advantages of target specificity and the ability to block large interacting interfaces, such as those of transcription factors. The transcription co-factor of the Hippo pathway, YAP/Yorkie (Yki), has been implicated in many cancers, and is dependent on its interaction with the DNA-binding TEAD/Sd proteins via a large Ω-loop. In addition, the mammalian vestigial-like (VGLL) proteins, specifically their TONDU domain, competitively inhibit YAP-TEAD interaction, resulting in arrest of tumor growth. Here, we show that overexpression of the TONDU peptide or its oral uptake leads to suppression of Yki-driven intestinal stem cell tumors in the adult Drosophila midgut. In addition, comparative proteomic analyses of peptide-treated and untreated tumors, together with chromatin immunoprecipitation analysis, reveal that integrin pathway members are part of the Yki-oncogenic network. Collectively, our findings establish Drosophila as a reliable in vivo platform to screen for cancer oral therapeutic peptides and reveal a tumor suppressive role for integrins in Yki-driven tumors.This article has an associated First Person interview with the first author of the paper.

scholarly journals Overexpression of TIMP3 Protects Against Cardiac Ischemia/Reperfusion Injury by Inhibiting Myocardial Apoptosis Through ROS/Mapks Pathway

2017 ◽  
Vol 44 (3) ◽  
pp. 1011-1023 ◽  
Author(s):  
Hui Liu ◽  
Xibo Jing ◽  
Aiqiao Dong ◽  
Baobao Bai ◽  
Haiyan Wang
Keyword(s):  
Myocardial Infarct ◽  
Ischemia Reperfusion ◽  
Neonatal Rat ◽  
Tunel Staining ◽  
Ros Production ◽  
Rat Cardiomyocytes ◽  
Doxorubicin Treatment ◽  
Myocardial Apoptosis

Background/Aims: Myocardial ischemia/reperfusion (I/R) injury remains a great challenge in clinical therapy. Tissue inhibitor of metalloproteinases 3 (TIMP3) plays a crucial role in heart physiological and pathophysiological processes. However, the effects of TIMP3 on I/R injury remain unknown. Methods: C57BL/6 mice were infected with TIMP3 adenovirus by local delivery in myocardium followed by I/R operation or doxorubicin treatment. Neonatal rat cardiomyocytes were pretreated with TIMP3 adenovirus prior to anoxia/reoxygenation (A/R) treatment in vitro. Histology, echocardiography, in vivo phenotypical analysis, flow cytometry and western blotting were used to investigate the altered cardiac function and underlying mechanisms. Results: The results showed that upregulation of TIMP3 in myocardium markedly inhibited myocardial infarct areas and the cardiac dysfunction induced by I/R or by doxorubicin treatment. TUNEL staining revealed that TIMP3 overexpression attenuated I/R-induced myocardial apoptosis, accompanied by decreased Bax/Bcl-2 ratio, Cleaved Caspase-3 and Cleaved Caspase-9 expression. In vitro, A/R-induced cardiomyocyte apoptosis was abrogated by pharmacological inhibition of reactive oxygen species (ROS) production or MAPKs signaling. Attenuation of ROS production reversed A/R-induced MAPKs activation, whereas MAPKs inhibitors showed on effect on ROS production. Furthermore, in vivo or in vitro overexpression of TIMP3 significantly inhibited I/R- or A/R-induced ROS production and MAPKs activation. Conclusion: Our findings demonstrate that TIMP3 upregulation protects against cardiac I/R injury through inhibiting myocardial apoptosis. The mechanism may be related to inhibition of ROS-initiated MAPKs pathway. This study suggests that TIMP3 may be a potential therapeutic target for the treatment of I/R injury.

The Nedd4-like ubiquitin E3 ligases target angiomotin/p130 to ubiquitin-dependent degradation

2012 ◽  
Vol 444 (2) ◽  
pp. 279-289 ◽  
Author(s):  
Chenji Wang ◽  
Jian An ◽  
Pingzhao Zhang ◽  
Chen Xu ◽  
Kun Gao ◽  
...  
Keyword(s):  
Hippo Pathway ◽  
State Level ◽  
Proteasomal Degradation ◽  
Binding Motif ◽  
Ww Domains ◽  
E3 Ligases ◽  
Tight Junction Formation ◽  
Junction Formation ◽  
The Hippo Pathway

AMOT (angiomotin) is a membrane-associated protein that is expressed in ECs (endothelial cells) and controls migration, TJ (tight junction) formation, cell polarity and angiogenesis. Recent studies have revealed that AMOT and two AMOT-like proteins, AMOTL1 and AMOTL2, play critical roles in the Hippo pathway by regulating the subcellular localization of the co-activators YAP (Yes-associated protein) and TAZ (transcriptional co-activator with PDZ-binding motif). However, it has been unclear how AMOT is regulated. In the present study, we report that AMOT undergoes proteasomal degradation. We identify three members of Nedd4 (neural-precursor-cell-expressed developmentally down-regulated)-like ubiquitin E3 ligases, Nedd4, Nedd4-2 and Itch, as the ubiquitin E3 ligases for the long isoform of AMOT, AMOT/p130. We demonstrate that Nedd4, Nedd4-2 and Itch mediate poly-ubiquitination of AMOT/p130 in vivo. Overexpression of Nedd4, Nedd4-2 or Itch leads to AMOT/p130 proteasomal degradation. Knockdown of Nedd4, Nedd4-2 and Itch causes an accumulation of steady-state level of AMOT/p130. We also show that three L/P-PXY motifs of AMOT/p130 and the WW domains of Nedd4 mediate their interaction. Furthermore, Nedd4-like ubiquitin E3 ligases might compete with YAP for the binding to AMOT/p130, and subsequently targeting AMOT/p130 for ubiquitin-dependent degradation. Together, these observations reveal a novel post-translational regulatory mechanism of AMOT/p130.

Sign in / Sign up

Export Citation Format

Share Document