Central role of SIAH inhibition in DCC-dependent cardioprotection provoked by netrin-1/NO

Deleted in colorectal cancer (DCC), a large transmembrane receptor of netrin-1, is critical for mediating netrin-1’s cardioprotective function. In the present study we investigated novel mechanisms underlying netrin-1–induced, rapid, and feed-forward up-regulation of DCC, which is believed to sustain nitric oxide (NO) production to potentiate cardioprotection. Intriguingly, NO markedly reduced expression of the E3 ubiquitin ligase seven in absentia homolog (SIAH) that is specific for regulation of protesome-dependent DCC degradation, resulting in accumulation of DCC. The two SIAH isoforms compensate for each other when one is repressed; inhibition of both SIAH1 and SIAH2 using combined siRNAs significantly reduced infarct size while improving cardiac function after ischemia/reperfusion injury of the heart. This effect was absent in DCC-deficient mice. Moreover, in vivo RNAi inhibition of SIAH1/2 further augmented netrin-1’s cardioprotective function. In summary, these data identify a novel therapeutic target of SIAH in facilitating NO/netrin-1–dependent cardioprotection, using the DCC receptor. Combination of netrin-1 and SIAH RNAi may prove to be a substantially effective therapy for myocardial infarction.

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Cardioprotective role of endogenous hydrogen peroxide during ischemia-reperfusion injury in canine coronary microcirculation in vivo

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00187.2006 ◽

2006 ◽

Vol 291 (3) ◽

pp. H1138-H1146 ◽

Cited By ~ 38

Author(s):

Toyotaka Yada ◽

Hiroaki Shimokawa ◽

Osamu Hiramatsu ◽

Yoshisuke Haruna ◽

Yoshitaka Morita ◽

...

Keyword(s):

Ischemia Reperfusion Injury ◽

Myocardial Infarct ◽

Ischemia Reperfusion ◽

Protective Role ◽

No Production ◽

Coronary Vasodilatation ◽

Before And After ◽

Nos Inhibitor

We have recently demonstrated that endogenous H2O2 plays an important role in coronary autoregulation in vivo. However, the role of H2O2 during coronary ischemia-reperfusion (I/R) injury remains to be examined. In this study, we examined whether endogenous H2O2 also plays a protective role in coronary I/R injury in dogs in vivo. Canine subepicardial small coronary arteries (≥100 μm) and arterioles (<100 μm) were continuously observed by an intravital microscope during coronary I/R (90/60 min) under cyclooxygenase blockade ( n = 50). Coronary vascular responses to endothelium-dependent vasodilators (ACh) were examined before and after I/R under the following seven conditions: control, nitric oxide (NO) synthase (NOS) inhibitor NG-monomethyl-l-arginine (l-NMMA), catalase (a decomposer of H2O2), 8-sulfophenyltheophylline (8-SPT, an adenosine receptor blocker), l-NMMA + catalase, l-NMMA + tetraethylammonium (TEA, an inhibitor of large-conductance Ca2+-sensitive potassium channels), and l-NMMA + catalase + 8-SPT. Coronary I/R significantly impaired the coronary vasodilatation to ACh in both sized arteries (both P < 0.01); l-NMMA reduced the small arterial vasodilatation (both P < 0.01), whereas it increased ( P < 0.05) the ACh-induced coronary arteriolar vasodilatation associated with fluorescent H2O2 production after I/R. Catalase increased the small arterial vasodilatation ( P < 0.01) associated with fluorescent NO production and increased endothelial NOS expression, whereas it decreased the arteriolar response after I/R ( P < 0.01). l-NMMA + catalase, l-NMMA + TEA, or l-NMMA + catalase + 8-SPT further decreased the coronary vasodilatation in both sized arteries (both, P < 0.01). l-NMMA + catalase, l-NMMA + TEA, and l-NMMA + catalase + 8-SPT significantly increased myocardial infarct area compared with the other four groups (control, l-NMMA, catalase, and 8-SPT; all, P < 0.01). These results indicate that endogenous H2O2, in cooperation with NO, plays an important cardioprotective role in coronary I/R injury in vivo.

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Role of α/β and γ/δ T cells in renal ischemia-reperfusion injury

AJP Renal Physiology ◽

10.1152/ajprenal.00486.2006 ◽

2007 ◽

Vol 293 (3) ◽

pp. F741-F747 ◽

Cited By ~ 31

Author(s):

Kathrin Hochegger ◽

Tobias Schätz ◽

Philipp Eller ◽

Andrea Tagwerker ◽

Dorothea Heininger ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Reperfusion Injury ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Renal Ischemia ◽

Wild Type ◽

Renal Ischemia Reperfusion Injury ◽

Deficient Mice

T cells have been implicated in the pathogenesis of renal ischemia-reperfusion injury (IRI). To date existing data about the role of the T cell receptor (Tcr) are contradictory. We hypothesize that the Tcr plays a prominent role in the late phase of renal IRI. Therefore, renal IRI was induced in α/β, γ/δ T cell-deficient and wild-type mice by clamping renal pedicles for 30 min and reperfusing for 24, 48, 72, and 120 h. Serum creatinine increased equally in all three groups 24 h after ischemia but significantly improved in Tcr-deficient animals compared with wild-type controls after 72 h. A significant reduction in renal tubular injury and infiltration of CD4+ T-cells in both Tcr-deficient mice compared with wild-type controls was detected. Infiltration of α/β T cells into the kidney was reduced in γ/δ T cell-deficient mice until 72 h after ischemia. In contrast, γ/δ T cell infiltration was equal in wild-type and α/β T cell-deficient mice, suggesting an interaction between α/β and γ/δ T cells. Data from γ/δ T cell-deficient mice were confirmed by in vivo depletion of γ/δ T cells in C57BL/6 mice. Whereas α/β T cell-deficient mice were still protected after 120 h, γ/δ T cell-deficient mice showed a “delayed wild-type phenotype” with a dramatic increase in kidney-infiltrating α/β, Tcr-expressing CD4+ T-cells. This report provides further evidence that α/β T cells are major effector cells in renal IRI, whereas γ/δ T cells play a role as mediator cells in the first 72 h of renal IRI.

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STIM1/Orai1-mediated SOCE: current perspectives and potential roles in cardiac function and pathology

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00104.2013 ◽

2013 ◽

Vol 305 (4) ◽

pp. H446-H458 ◽

Cited By ~ 71

Author(s):

Helen E. Collins ◽

Xiaoyuan Zhu-Mauldin ◽

Richard B. Marchase ◽

John C. Chatham

Keyword(s):

Cardiac Function ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Molecular Regulation ◽

Cardiomyocyte Hypertrophy ◽

Substantial Evidence ◽

Contraction Coupling

Store-operated Ca2+ entry (SOCE) is critical for Ca2+ signaling in nonexcitable cells; however, its role in the regulation of cardiomyocyte Ca2+ homeostasis has only recently been investigated. The increased understanding of the role of stromal interaction molecule 1 (STIM1) in regulating SOCE combined with recent studies demonstrating the presence of STIM1 in cardiomyocytes provides support that this pathway co-exists in the heart with the more widely recognized Ca2+ handling pathways associated with excitation-contraction coupling. There is now substantial evidence that STIM1-mediated SOCE plays a key role in mediating cardiomyocyte hypertrophy, both in vitro and in vivo, and there is growing support for the contribution of SOCE to Ca2+ overload associated with ischemia/reperfusion injury. Here, we provide an overview of our current understanding of the molecular regulation of SOCE and discuss the evidence supporting the role of STIM1/Orai1-mediated SOCE in regulating cardiomyocyte function.

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Up-regulation of MicroRNA-21 Mediates Isoflurane-induced Protection of Cardiomyocytes

Anesthesiology ◽

10.1097/aln.0000000000000567 ◽

2015 ◽

Vol 122 (4) ◽

pp. 795-805 ◽

Cited By ~ 29

Author(s):

Jessica M. Olson ◽

Yasheng Yan ◽

Xiaowen Bai ◽

Zhi-Dong Ge ◽

Mingyu Liang ◽

...

Keyword(s):

Cell Death ◽

Programmed Cell Death ◽

Messenger Rna ◽

Functional Role ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Cell Death Protein

Abstract Background: Anesthetic cardioprotection reduces myocardial infarct size after ischemia–reperfusion injury. Currently, the role of microRNA in this process remains unknown. MicroRNAs are short, noncoding nucleotide sequences that negatively regulate gene expression through degradation or suppression of messenger RNA. In this study, the authors uncovered the functional role of microRNA-21 (miR-21) up-regulation after anesthetic exposure. Methods: MicroRNA and messenger RNA expression changes were analyzed by quantitative real-time polymerase chain reaction in cardiomyocytes after exposure to isoflurane. Lactate dehydrogenase release assay and propidium iodide staining were conducted after inhibition of miR-21. miR-21 target expression was analyzed by Western blot. The functional role of miR-21 was confirmed in vivo in both wild-type and miR-21 knockout mice. Results: Isoflurane induces an acute up-regulation of miR-21 in both in vivo and in vitro rat models (n = 6, 247.8 ± 27.5% and 258.5 ± 9.0%), which mediates protection to cardiomyocytes through down-regulation of programmed cell death protein 4 messenger RNA (n = 3, 82.0 ± 4.9% of control group). This protective effect was confirmed by knockdown of miR-21 and programmed cell death protein 4 in vitro. In addition, the protective effect of isoflurane was abolished in miR-21 knockout mice in vivo, with no significant decrease in infarct size compared with nonexposed controls (n = 8, 62.3 ± 4.6% and 56.2 ± 3.2%). Conclusions: The authors demonstrate for the first time that isoflurane mediates protection of cardiomyocytes against oxidative stress via an miR-21/programmed cell death protein 4 pathway. These results reveal a novel mechanism by which the damage done by ischemia/reperfusion injury may be decreased.

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cGAS-mediated autophagy protects the liver from ischemia-reperfusion injury independently of STING

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00326.2017 ◽

2018 ◽

Vol 314 (6) ◽

pp. G655-G667 ◽

Cited By ~ 20

Author(s):

Zhao Lei ◽

Meihong Deng ◽

Zhongjie Yi ◽

Qian Sun ◽

Richard A. Shapiro ◽

...

Keyword(s):

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Adenosine Monophosphate ◽

Cyclic Guanosine Monophosphate ◽

Protective Role ◽

Guanosine Monophosphate ◽

Independent Manner

Liver ischemia-reperfusion (I/R) injury occurs through induction of oxidative stress and release of damage-associated molecular patterns (DAMPs), including cytosolic DNA released from dysfunctional mitochondria or from the nucleus. Cyclic guanosine monophosphate–adenosine monophosphate (cGAMP) synthase (cGAS) is a cytosolic DNA sensor known to trigger stimulator of interferon genes (STING) and downstream type 1 interferon (IFN-I) pathways, which are pivotal innate immune system responses to pathogen. However, little is known about the role of cGAS/STING in liver I/R injury. We subjected C57BL/6 (WT), cGAS knockout (cGAS−/−), and STING-deficient (STINGgt/gt) mice to warm liver I/R injury and that found cGAS−/− mice had significantly increased liver injury compared with WT or STINGgt/gt mice, suggesting a protective effect of cGAS independent of STING. Liver I/R upregulated cGAS in vivo and also in vitro in hepatocytes subjected to anoxia/reoxygenation (A/R). We confirmed a previously published finding that hepatocytes do not express STING under normoxic conditions or after A/R. Hepatocytes and liver from cGAS−/− mice had increased cell death and reduced induction of autophagy under hypoxic conditions as well as increased apoptosis. Protection could be restored in cGAS−/− hepatocytes by overexpression of cGAS or by pretreatment of mice with autophagy inducer rapamycin. Our findings indicate a novel protective role for cGAS in the regulation of autophagy during liver I/R injury that occurs independently of STING. NEW & NOTEWORTHY Our studies are the first to document the important role of cGAS in the acute setting of sterile injury induced by I/R. Specifically, we provide evidence that cGAS protects liver from I/R injury in a STING-independent manner.

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Protective role of ischemic conditioning procedures against skeletal muscle ischemia-reperfusion injury via improving in vivo energy metabolism and mitochondrial function

Archives of Cardiovascular Diseases Supplements ◽

10.1016/s1878-6480(17)30466-4 ◽

2017 ◽

Vol 9 (2) ◽

pp. 188

Author(s):

A. Delgove ◽

D. Detaille ◽

J. Retortillo Garcia ◽

J. Magat ◽

V. Loyer ◽

...

Keyword(s):

Skeletal Muscle ◽

Energy Metabolism ◽

Mitochondrial Function ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Protective Role ◽

Ischemic Conditioning ◽

Muscle Ischemia

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The E3 Ubiquitin Ligase Cbl-b Limits Nascent Th9 Differentiation

Blood ◽

10.1182/blood.v126.23.2222.2222 ◽

2015 ◽

Vol 126 (23) ◽

pp. 2222-2222

Author(s):

Isabelle Cornez ◽

Sowmya Parampalli Yajnanarayana ◽

Natascha Hermann-Kleiter ◽

Stefan Ulrich Schmidt ◽

Peter Brossart ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Ubiquitin Ligase ◽

Cd4 T Cells ◽

Lung Inflammation ◽

E3 Ubiquitin Ligase ◽

Th9 Cells ◽

Deficient Mice ◽

Th9 Cell

Abstract Introduction: Th9 cells are critical mediators of allergy and anti-cancer immunity. The E3 ubiquitin ligase Cbl-b modulates T cell activation via regulation of the T cell receptor (TCR) activation threshold as well as by inducing TGF-β sensitivity, which is a critical differentiation factor for Th9 differentiation. Even though some evidence shows that Cbl-b impairs Th9 differentiation by targeting IL-4 dependent STAT6 activation, a complete suppression of Th9 differentiation in the absence of both STAT6 and Cbl-b is not achieved, implying the involvement of additional mechanisms. In this study, we evaluate the role of Cbl-b in early stages of TGF-β dependent Th9 differentiation. Methods: Th9 cells were generated from WT and cblb-deficient naïve CD4+ T cells. After maximum 3 days in presence of IL-4, TGF-β and anti-IFN-γ antibodies, differentiation was determined by the quantification of cytokines, mainly IL-9, and that of the two required transcription factors for Th9 differentiation, namely IRF4 and PU.1. Microarray assay revealed gene candidates that were further validated by mRNA and protein expression analysis. The functional role of Cbl-b was tested in a Th9-mediated murine lung allergy model, in which mice were challenged by intratracheal injections of house dust mite (HDM) extracts. Results: cblb-deficient naïve T cells more efficiently differentiate into Th9 cells after 3 days in culture, express in parallel PU.1 more intensively compared to WT Th9 cells, while retaining similar expression levels of IRF4, another important Th9 differentiation factor. Increased IL-9 level is not based on cblb -deficient T cell hyperproliferation, as we show an increased IL-9 production per cell by using combination of CFSE with intracellular IL-9 staining. Microarray analysis revealed that RUNX1, a known transcriptional modulator of PU.1, is more rapidly down-regulated in cblb-deficient Th9 cells compared to WT Th9 cells. Accordingly, knocking down RUNX1 by siRNA in naïve CD4+ T cells and subsequently differentiating them into Th9 cells, also induces higher IL-9 expression at the mRNA and protein levels in RUNX1-depleted Th9 cells compared to control scrambled siRNA-nucleofected Th9 cells. In the HDM murine allergy model, cblb-deficient mice have a higher lung inflammation as mirrored by increased eosinophils in the BAL and in the lungs, as well as by increased IgE production in the blood. These are also paralleled by an increased IL-9 expression level in the lungs of the allergic cblb -deficient mice. Conclusions: Cbl-b critically limits Th9 differentiation and may thus be a potential target to modify Th9 cell generation in allergy or cancer. Future studies will validate the molecular link that exists between Cbl-b and the RUNX1-dependent IL-9 expression as well as the in vivo significance of increased Th9 cell differentiation in cblb-deficient animal models of lung inflammation and cancer. Disclosures No relevant conflicts of interest to declare.

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