Abstract 293: MicroRNA-125b-5p Protect the Mouse Heart from Ischemic Injury by Repressing Pro-apoptotic Bak1 And Klf13 in Cardiomyocytes

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Zuzana Broskova ◽  
Kyoung-mi Park ◽  
Yongchao Wang ◽  
Il-man Kim
Keyword(s):  
Target Genes ◽  
Cardiac Injury ◽  
Ischemic Injury ◽  
Mouse Heart ◽  
Loss Of Function ◽  
Increased Sensitivity ◽  
Induced Apoptosis ◽  
End Stage ◽  
And Function

Cardiac injury is accompanied by dynamic changes in the expression of microRNAs (miRs), small non-coding RNAs that post-transcriptionally regulate target genes. For example, miR-125a is up-regulated in patients with heart failure (HF), while miR-125b is down-regulated in patients with end-stage dilated cardiomyopathy (DCM) and ischemic DCM. Circulating levels of these two miRs have been recently proposed as potential biomarkers of HF. We previously showed that β1-adrenergic receptor-mediated cardioprotective signaling through β-arrestin1 stimulates the processing of miR-125a and miR-125b in mouse heart (Figure A-C). Here, we hypothesize that these two miRs might confer cardioprotection against ischemic injury. Using cultured cardiomyocyte (CM) and in vivo approaches, we show that these miRs are ischemic stress-responsive protectors against CM apoptosis. CMs lacking miR-125a or miR-125b have an increased sensitivity to stress-induced apoptosis, while CMs overexpressing miR-125a or miR-125b have increased phospho-AKT pro-survival signaling. Moreover, we demonstrate that loss-of-function of miR-125b in mouse heart causes abnormalities in cardiac structure and function after myocardial infarction. The cardioprotective roles of the two miRs during ischemic injury are in part attributed to direct repression of the pro-apoptotic genes Bak1 and Klf13 in CMs (Figure D). In conclusion, these findings reveal pivotal roles for miR-125a and miR-125b as important regulators of CM survival during cardiac injury.

Abstract 277: MicroRNA-125a-5p Protects the Mouse Heart From Ischemic Injury by Repressing Pro-apoptotic Bak1 and Klf13 in Cardiomyocytes

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Bruno Moukette ◽  
Tatsuya Aonuma ◽  
Il-man Kim
Keyword(s):  
Target Genes ◽  
Cardiac Injury ◽  
Cell Types ◽  
Mouse Heart ◽  
Small Noncoding Rnas ◽  
Increased Sensitivity ◽  
Β Blocker ◽  
Apoptotic Genes

Background: Cardiac injury is accompanied by dynamic changes in the expression of microRNAs (miRs), which are small noncoding RNAs to downregulate target genes. MiR-125a-5p (miR-125a) is downregulated in patients with myocardial infarction (MI). We reported that miR-125a is upregulated by the β-blocker carvedilol (Carv) acting through β-arrestin1-biased β1-adrenergic receptor (β1AR; receptor found mainly in cardiomyocytes [CMs]) cardioprotective signaling (Figure A). We also showed that pro-apoptotic genes bak1 and klf13 are downregulated by Carv and are upregulated after MI. Here, we hypothesize that miR-125a in CMs favorably regulates cardiac functional and structural remodeling after MI by repressing bak1 and klf13. Methods and Results: Fractionation of cardiac cell types from heart tissues reveals that the expression of miR-125a is higher in CMs than other myocardial cells. Using cultured CM and in vivo approaches, we show that miR-125a is an ischemic stress-responsive protector against CM apoptosis. CMs lacking miR-125a exhibit an increased sensitivity to apoptosis, while CMs overexpressing miR-125a have increased phospho-AKT pro-survival signaling. Moreover, we show that miR-125a is downregulated in post-MI mouse hearts and miR-125a overexpression protects mouse hearts against MI. We also show that global genetic deletion of miR-125a in mice worsens maladaptive post-MI remodeling. Mechanistically, the cardioprotective role of miR-125a during MI is in part attributed to direct repression of the pro-apoptotic genes bak1 and klf13 in CMs (Figure B). Conclusions: These findings reveal a pivotal role for miR-125a in regulating CM survival during MI.

Abstract 206: Stem Cell-derived Exosomes Induce Cardiac Repair via mRNA Modification

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Prabhu Mathiyalagan ◽  
Yaxuan Liang ◽  
Adriano S Martins ◽  
Douglas W Losordo ◽  
Roger J Hajjar ◽  
...  
Keyword(s):  
Stem Cell ◽  
Myocardial Ischemia ◽  
Target Genes ◽  
Critical Role ◽  
Cell Communication ◽  
Target Cells ◽  
Mouse Heart ◽  
Loss Of Function

Exosomes are cell-derived nanovesicles that carry and shuttle microRNAs (miRNAs) to mediate cell-cell communication. Vast majority of cell types including cardiac myocytes and progenitors actively secrete exosomes, whose miRNA contents are altered after physiological or pathological changes such as myocardial ischemia (MI). In this new study, we have discovered that chemical modification to mRNAs is a novel regulator of ischemia-induced gene expression changes in the heart. We hypothesized that the benefits of human CD34 + stem cell-derived exosomes (CD34exo) are mediated by mRNA modifications in the target cells via miRNA delivery. MiRNA profiling and bioinformatic analysis identified that CD34exo is selectively enriched with a number of miRNAs that directly target genes implicated in regulation of mRNA modifications. Interestingly, under myocardial ischemia, there was a significant increase in mRNA modifications in the mouse heart, which was decreased by about 70% with CD34exo-treatment. In line with the in vivo MI data, in vitro hypoxic stimulation in neonatal / adult rodent myocytes and non-myocytes increased mRNA modifications and controls known regulators of those mRNA modifications. Loss-of-function studies for regulators of mRNA modifications attenuated hypoxia-induced changes to epitranscriptome indicating important roles for these molecules under stress conditions. Finally, using gain-of-function and loss-of-function studies, we demonstrate that miR-126, one of the most enriched miRNAs in CD34exo, plays a critical role in regulating the mRNA modifications. We conclude that miRNAs enriched in CD34exo mediate their cardioprotective effect at least in part, by regulating the mRNA epitranscriptome of the target cell. Our new data suggests hypoxia as a novel regulator of the mRNA epitranscriptome and provides novel insights to post-transcriptional gene regulation in the heart.

scholarly journals A Conserved Myc Protein Domain, MBIV, Regulates DNA Binding, Apoptosis, Transformation, and G2 Arrest

2006 ◽  
Vol 26 (11) ◽  
pp. 4226-4239 ◽  
Author(s):  
Victoria H. Cowling ◽  
Sanjay Chandriani ◽  
Michael L. Whitfield ◽  
Michael D. Cole
Keyword(s):  
Dna Binding ◽  
Target Genes ◽  
Binding Activity ◽  
Protein Domain ◽  
Loss Of Function ◽  
Dna Binding Activity ◽  
Induced Apoptosis

ABSTRACT The myc family of oncogenes is well conserved throughout evolution. Here we present the characterization of a domain conserved in c-, N-, and L-Myc from fish to humans, N-Myc317-337, designated Myc box IV (MBIV). A deletion of this domain leads to a defect in Myc-induced apoptosis and in some transformation assays but not in cell proliferation. Unlike other Myc mutants, MycΔMBIV is not a simple loss-of-function mutant because it is hyperactive for G2 arrest in primary cells. Microarray analysis of genes regulated by N-MycΔMBIV reveals that it is weakened for transactivation and repression but not nearly as defective as N-MycΔMBII. Although the mutated region is not part of the previously defined DNA binding domain, we find that N-MycΔMBIV has a significantly lower affinity for DNA than the wild-type protein in vitro. Furthermore, chromatin immunoprecipitation shows reduced binding of N-MycΔMBIV to some target genes in vivo, which correlates with the defect in transactivation. Thus, this conserved domain has an unexpected role in Myc DNA binding activity. These data also provide a novel separation of Myc functions linked to the modulation of DNA binding activity.

scholarly journals DJ-1 regulates the integrity and function of ER-mitochondria association through interaction with IP3R3-Grp75-VDAC1

2019 ◽  
Vol 116 (50) ◽  
pp. 25322-25328 ◽  
Author(s):  
Yi Liu ◽  
Xiaopin Ma ◽  
Hisashi Fujioka ◽  
Jun Liu ◽  
Shengdi Chen ◽  
...  
Keyword(s):  
Autosomal Recessive ◽  
Cellular Mechanism ◽  
Loss Of Function ◽  
Wild Type ◽  
Calcium Efflux ◽  
And Function ◽  
The Brain ◽  
Early Onset Parkinson’S Disease

Loss-of-function mutations in DJ-1 are associated with autosomal recessive early onset Parkinson’s disease (PD), yet the underlying pathogenic mechanism remains elusive. Here we demonstrate that DJ-1 localized to the mitochondria-associated membrane (MAM) both in vitro and in vivo. In fact, DJ-1 physically interacts with and is an essential component of the IP3R3-Grp75-VDAC1 complexes at MAM. Loss of DJ-1 disrupted the IP3R3-Grp75-VDAC1 complex and led to reduced endoplasmic reticulum (ER)-mitochondria association and disturbed function of MAM and mitochondria in vitro. These deficits could be rescued by wild-type DJ-1 but not by the familial PD-associated L166P mutant which had demonstrated reduced interaction with IP3R3-Grp75. Furthermore, DJ-1 ablation disturbed calcium efflux-induced IP3R3 degradation after carbachol treatment and caused IP3R3 accumulation at the MAM in vitro. Importantly, similar deficits in IP3R3-Grp75-VDAC1 complexes and MAM were found in the brain of DJ-1 knockout mice in vivo. The DJ-1 level was reduced in the substantia nigra of sporadic PD patients, which was associated with reduced IP3R3-DJ-1 interaction and ER-mitochondria association. Together, these findings offer insights into the cellular mechanism in the involvement of DJ-1 in the regulation of the integrity and calcium cross-talk between ER and mitochondria and suggests that impaired ER-mitochondria association could contribute to the pathogenesis of PD.

NFATc3 regulates the transcription of genes involved in T-cell activation and angiogenesis

Blood ◽  
2011 ◽  
Vol 118 (3) ◽  
pp. 795-803 ◽  
Author(s):  
Katia Urso ◽  
Arantzazu Alfranca ◽  
Sara Martínez-Martínez ◽  
Amelia Escolano ◽  
Inmaculada Ortega ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Target Genes ◽  
Gene Knockout ◽  
Activated T Cells ◽  
Knock Down ◽  
And Function

Abstract The nuclear factor of activated T cells (NFAT) family of transcription factors plays important roles in many biologic processes, including the development and function of the immune and vascular systems. Cells usually express more than one NFAT member, raising the question of whether NFATs play overlapping roles or if each member has selective functions. Using mRNA knock-down, we show that NFATc3 is specifically required for IL2 and cyclooxygenase-2 (COX2) gene expression in transformed and primary T cells and for T-cell proliferation. We also show that NFATc3 regulates COX2 in endothelial cells, where it is required for COX2, dependent migration and angiogenesis in vivo. These results indicate that individual NFAT members mediate specific functions through the differential regulation of the transcription of target genes. These effects, observed on short-term suppression by mRNA knock-down, are likely to have been masked by compensatory effects in gene-knockout studies.

scholarly journals The Ubiquitously Expressed Csk Adaptor Protein Cbp Is Dispensable for Embryogenesis and T-Cell Development and Function

2005 ◽  
Vol 25 (23) ◽  
pp. 10533-10542 ◽  
Author(s):  
Marc-Werner Dobenecker ◽  
Christian Schmedt ◽  
Masato Okada ◽  
Alexander Tarakhovsky
Keyword(s):  
T Cell ◽  
Adaptor Protein ◽  
Regulatory Function ◽  
Loss Of Function ◽  
Thymic Development ◽  
Cell Functions ◽  
Carboxy Terminal ◽  
And Function

ABSTRACT Regulation of Src family kinase (SFK) activity is indispensable for a functional immune system and embryogenesis. The activity of SFKs is inhibited by the presence of the carboxy-terminal Src kinase (Csk) at the cell membrane. Thus, recruitment of cytosolic Csk to the membrane-associated SFKs is crucial for its regulatory function. Previous studies utilizing in vitro and transgenic models suggested that the Csk-binding protein (Cbp), also known as phosphoprotein associated with glycosphingolipid microdomains (PAG), is the membrane adaptor for Csk. However, loss-of-function genetic evidence to support this notion was lacking. Herein, we demonstrate that the targeted disruption of the cbp gene in mice has no effect on embryogenesis, thymic development, or T-cell functions in vivo. Moreover, recruitment of Csk to the specialized membrane compartment of “lipid rafts” is not impaired by Cbp deficiency. Our results indicate that Cbp is dispensable for the recruitment of Csk to the membrane and that another Csk adaptor, yet to be discovered, compensates for the loss of Cbp.

Abstract O-3: A β1-Adrenergic Receptor/β-Arrestin1-Regulatable MicroRNA, MiR-150 Protects the Mouse Heart from Ischemic Injury by Repressing Pro-apoptotic Egr2 and P2x7r

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Il-man Kim ◽  
Yaoping Tang ◽  
Yongchao Wang ◽  
Kyoung-mi Park ◽  
Qiuping Hu
Keyword(s):  
Adrenergic Receptor ◽  
Cardiac Injury ◽  
Ischemic Injury ◽  
Mouse Heart ◽  
Functional Remodeling ◽  
Β Blocker ◽  
Genetic Deletion ◽  
Circulating Levels ◽  
Cardiomyocyte Survival

MicroRNA (miR)-150 is down-regulated in patients with acute myocardial infarction (AMI), atrial fibrillation, dilated and ischemic cardiomyopathy as well as in various mouse heart failure (HF) models. Circulating miR-150 has been recently proposed as a better biomarker of HF than clinically used markers such as brain natriuretic peptide. We recently showed that β-arrestin1-biased β1-adrenergic receptor (β1AR) cardioprotective signaling activated by the β-arrestin-biased β-blocker, carvedilol (Carv) stimulates the processing of miR-150 in the heart (see figure A). However, the potential role of miR-150 in ischemic injury and HF is unknown. Here, we show that genetic deletion of miR-150 in mice causes abnormalities in cardiac structural and functional remodeling after MI. The cardioprotective roles of miR-150 during ischemic injury were attributed to repression of the pro-apoptotic genes egr2 (zinc binding transcription factor induced by ischemia) and p2x7r (pro-inflammatory ATP receptor) [see figure B]. These findings reveal a pivotal role for miR-150 as a regulator of cardiomyocyte survival during cardiac injury. In conclusion, our study will help to stratify HF patients that may respond better to β-arrestin-biased β-blockers, which is guided by circulating levels of miR-150.

scholarly journals Mediator complex subunit Med19 binds directly GATA transcription factors and is required with Med1 for GATA-driven gene regulation in vivo

2020 ◽  
Vol 295 (39) ◽  
pp. 13617-13629
Author(s):  
Clément Immarigeon ◽  
Sandra Bernat-Fabre ◽  
Emmanuelle Guillou ◽  
Alexis Verger ◽  
Elodie Prince ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Target Genes ◽  
Direct Interaction ◽  
Mediator Complex ◽  
Loss Of Function ◽  
Transcriptional Responses ◽  
Rna Pol Ii ◽  
Evolutionarily Conserved

The evolutionarily conserved multiprotein Mediator complex (MED) serves as an interface between DNA-bound transcription factors (TFs) and the RNA Pol II machinery. It has been proposed that each TF interacts with a dedicated MED subunit to induce specific transcriptional responses. But are these binary partnerships sufficient to mediate TF functions? We have previously established that the Med1 Mediator subunit serves as a cofactor of GATA TFs in Drosophila, as shown in mammals. Here, we observe mutant phenotype similarities between another subunit, Med19, and the Drosophila GATA TF Pannier (Pnr), suggesting functional interaction. We further show that Med19 physically interacts with the Drosophila GATA TFs, Pnr and Serpent (Srp), in vivo and in vitro through their conserved C-zinc finger domains. Moreover, Med19 loss of function experiments in vivo or in cellulo indicate that it is required for Pnr- and Srp-dependent gene expression, suggesting general GATA cofactor functions. Interestingly, Med19 but not Med1 is critical for the regulation of all tested GATA target genes, implying shared or differential use of MED subunits by GATAs depending on the target gene. Lastly, we show a direct interaction between Med19 and Med1 by GST pulldown experiments indicating privileged contacts between these two subunits of the MED middle module. Together, these findings identify Med19/Med1 as a composite GATA TF interface and suggest that binary MED subunit–TF partnerships are probably oversimplified models. We propose several mechanisms to account for the transcriptional regulation of GATA-targeted genes.

Genetic evidence for the transcriptional-activating function of Homothorax during adult fly development

Development ◽  
2001 ◽  
Vol 128 (18) ◽  
pp. 3405-3413 ◽  
Author(s):  
Adi Inbal ◽  
Naomi Halachmi ◽  
Charna Dibner ◽  
Dale Frank ◽  
Adi Salzberg
Keyword(s):  
Transcriptional Activity ◽  
Target Genes ◽  
Genetic Evidence ◽  
In Vivo Studies ◽  
Loss Of Function ◽  
Native Form ◽  
Downstream Target ◽  
Activating Function

Homothorax (HTH) is a homeobox-containing protein, which plays multiple roles in the development of the embryo and the adult fly. HTH binds to the homeotic cofactor Extradenticle (EXD) and translocates it to the nucleus. Its function within the nucleus is less clear. It was shown, mainly by in vitro studies, that HTH can bind DNA as a part of ternary HTH/EXD/HOX complexes, but little is known about the transcription regulating function of HTH-containing complexes in the context of the developing fly. Here we present genetic evidence, from in vivo studies, for the transcriptional-activating function of HTH. The HTH protein was forced to act as a transcriptional repressor by fusing it to the Engrailed (EN) repression domain, or as a transcriptional activator, by fusing it to the VP16 activation domain, without perturbing its ability to translocate EXD to the nucleus. Expression of the repressing form of HTH in otherwise wild-type imaginal discs phenocopied hth loss of function. Thus, the repressing form was working as an antimorph, suggesting that normally HTH is required to activate the transcription of downstream target genes. This conclusion was further supported by the observation that the activating form of HTH caused typical hth gain-of-function phenotypes and could rescue hth loss-of-function phenotypes. Similar results were obtained with XMeis3, the Xenopus homologue of HTH, extending the known functional similarity between the two proteins. Competition experiments demonstrated that the repressing forms of HTH or XMeis3 worked as true antimorphs competing with the transcriptional activity of the native form of HTH. We also describe the phenotypic consequences of HTH antimorph activity in derivatives of the wing, labial and genital discs. Some of the described phenotypes, for example, a proboscis-to-leg transformation, were not previously associated with alterations in HTH activity. Observing the ability of HTH antimorphs to interfere with different developmental pathways may direct us to new targets of HTH. The HTH antimorph described in this work presents a new means by which the transcriptional activity of the endogenous HTH protein can be blocked in an inducible fashion in any desired cells or tissues without interfering with nuclear localization of EXD.

Identification of apoptotic genes mediating TGF-β/Smad3-induced cell death in intestinal epithelial cells using a genomic approach

2007 ◽  
Vol 292 (1) ◽  
pp. G28-G38 ◽  
Author(s):  
Yanna Cao ◽  
Lu Chen ◽  
Weili Zhang ◽  
Yan Liu ◽  
Harry T. Papaconstantinou ◽  
...  
Keyword(s):  
Caspase 3 ◽  
Target Genes ◽  
Transforming Growth Factor ◽  
Intestinal Epithelial ◽  
Cytochrome C Release ◽  
Apoptotic Pathway ◽  
Genomic Approach ◽  
Apoptotic Genes ◽  
Induced Apoptosis

Transforming growth factor (TGF)-β-dependent apoptosis is important in the elimination of damaged or abnormal cells from normal tissues in vivo. Previously, we have shown that TGF-β inhibits the growth of rat intestinal epithelial (RIE)-1 cells. However, RIE-1 cells are relatively resistant to TGF-β-induced apoptosis due to a low endogenous Smad3-to-Akt ratio. Overexpression of Smad3 sensitizes RIE-1 cells (RIE-1/Smad3) to TGF-β-induced apoptosis by altering the Smad3-to-Akt ratio in favor of apoptosis. In this study, we utilized a genomic approach to identify potential downstream target genes that are regulated by TGF-β/Smad3. Total RNA samples were analyzed using Affymetrix oligonucleotide microarrays. We found that TGF-β regulated 518 probe sets corresponding to its target genes. Interestingly, among the known apoptotic genes included in the microarray analyses, only caspase-3 was induced, which was confirmed by real-time RT-PCR. Furthermore, TGF-β activated caspase-3 through protein cleavage. Upstream of caspase-3, TGF-β induced mitochondrial depolarization, cytochrome c release, and cleavage of caspase-9, which suggests that the intrinsic apoptotic pathway mediates TGF-β-induced apoptosis in RIE-1/Smad3 cells.

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