scholarly journals Binding of LncRNA-DACH1 to dystrophin impairs the membrane trafficking of Nav1.5 protein and increases ventricular arrhythmia susceptibility

2021 ◽  
Author(s):  
Zhenwei Pan ◽  
Gen-Long Xue ◽  
Yang Zhang ◽  
Jiming Yang ◽  
Ying Yang ◽  
...  
Keyword(s):  
Ventricular Arrhythmia ◽  
Membrane Trafficking ◽  
Ex Vivo ◽  
Conditional Knockout ◽  
Human Homologue ◽  
Interacting Protein ◽  
Membrane Anchoring ◽  
Ventricular Arrhythmogenesis

Abstract Dystrophin is a critical interacting protein of Nav1.5 that determines its membrane anchoring in cardiomyocytes. The study aims to explore whether lncRNA-DACH1(lncDACH1) can regulate the distribution of Nav1.5 by binding to dystrophin and participate in ventricular arrhythmogenesis. LncDACH1 was confirmed to bind to dystrophin. Cardiomyocyte-specific transgenic overexpression of lncDACH1(lncDACH1-TG) reduced the membrane distribution of dystrophin and Nav1.5 in cardiomyocytes. The opposite data were collected from lncDACH1 cardiomyocyte conditional knockout (lncDACH1-CKO) mice. Moreover, increased ventricular arrhythmia susceptibility was observed in lncDACH1-TG mice in vivo and ex vivo. The conservative fragment of lncDACH1 inhibited membrane distribution of dystrophin and Nav1.5 and promoted the inducibility of ventricular arrhythmia. Upregulation of dystrophin in lncDACH1-TG mice rescued the impaired membrane distribution of dystrophin and Nav1.5. The human homologue of lncDACH1 inhibited the membrane distribution of Nav1.5 in human iPS-differentiated cardiomyocytes. Collectively, lncDACH1 regulates Nav1.5 membrane distribution by binding to dystrophin and participates in ventricular arrhythmogenesis.

IRF6 and TAK1 coordinately promote the activation of HIPK2 to stimulate apoptosis during palate fusion

2019 ◽  
Vol 12 (593) ◽  
pp. eaav7666 ◽  
Author(s):  
Chen-Yeh Ke ◽  
Hua-Hsuan Mei ◽  
Fen-Hwa Wong ◽  
Lun-Jou Lo
Keyword(s):  
Transcription Factor ◽  
Cell Apoptosis ◽  
Transforming Growth Factor ◽  
Kinase Inhibitor ◽  
Ex Vivo ◽  
Human Cancer ◽  
Ectopic Expression ◽  
Interacting Protein ◽  
Human Cancer Cells

Cleft palate is a common craniofacial defect caused by a failure in palate fusion. The palatal shelves migrate toward one another and meet at the embryonic midline, creating a seam. Transforming growth factor–β3 (TGF-β3)–induced apoptosis of the medial edge epithelium (MEE), the cells located along the seam, is required for completion of palate fusion. The transcription factor interferon regulatory factor 6 (IRF6) promotes TGF-β3–induced MEE cell apoptosis by stimulating the degradation of the transcription factor ΔNp63 and promoting the expression of the gene encoding the cyclin-dependent kinase inhibitor p21. Because homeodomain-interacting protein kinase 2 (HIPK2) functions downstream of IRF6 in human cancer cells and is required for ΔNp63 protein degradation in keratinocytes, we investigated whether HIPK2 played a role in IRF6-induced ΔNp63 degradation in palate fusion. HIPK2 was present in the MEE cells of mouse palatal shelves during seam formation in vivo, and ectopic expression of IRF6 in palatal shelves cultured ex vivo stimulated the expression of Hipk2 and the accumulation of phosphorylated HIPK2. Knockdown and ectopic expression experiments in organ culture demonstrated that p21 was required for HIPK2- and IRF6-dependent activation of caspase 3, MEE apoptosis, and palate fusion. Contact between palatal shelves enhanced the phosphorylation of TGF-β–activated kinase 1 (TAK1), which promoted the phosphorylation of HIPK2 and palate fusion. Our findings demonstrate that HIPK2 promotes seam cell apoptosis and palate fusion downstream of IRF6 and that IRF6 and TAK1 appear to coordinately enhance the abundance and activation of HIPK2 during palate fusion.

scholarly journals CHIP Represses Myocardin-Induced Smooth Muscle Cell Differentiation via Ubiquitin-Mediated Proteasomal Degradation

2009 ◽  
Vol 29 (9) ◽  
pp. 2398-2408 ◽  
Author(s):  
Ping Xie ◽  
Yongna Fan ◽  
Hua Zhang ◽  
Yuan Zhang ◽  
Mingpeng She ◽  
...  
Keyword(s):  
Gene Expression ◽  
Smooth Muscle ◽  
Molecular Mechanisms ◽  
Serum Response Factor ◽  
Ex Vivo ◽  
Critical Role ◽  
Physiological Control ◽  
Interacting Protein

ABSTRACT Myocardin, a coactivator of serum response factor (SRF), plays a critical role in the differentiation of vascular smooth muscle cells (SMCs). However, the molecular mechanisms regulating myocardin stability and activity are not well defined. Here we show that the E3 ligase C terminus of Hsc70-interacting protein (CHIP) represses myocardin-dependent SMC gene expression and transcriptional activity. CHIP interacts with and promotes myocardin ubiquitin-mediated degradation by the proteasome in vivo and in vitro. Furthermore, myocardin ubiquitination by CHIP requires its phosphorylation. Importantly, CHIP overexpression reduces the level of myocardin-dependent SMC contractile gene expression and diminishes arterial contractility ex vivo. These findings for the first time, to our knowledge, demonstrate that CHIP-promoted proteolysis of myocardin plays a key role in the physiological control of SMC phenotype and vessel tone, which may have an important implication for pathophysiological conditions such as atherosclerosis, hypertension, and Alzheimer's disease.

scholarly journals Expression Silencing of Glutathione Peroxidase 4 in Mouse Erythroleukemia Cells Delays In Vitro Erythropoiesis

2021 ◽  
Vol 22 (15) ◽  
pp. 7795
Author(s):  
Marlena Rademacher ◽  
Hartmut Kuhn ◽  
Astrid Borchert
Keyword(s):  
Glutathione Peroxidase ◽  
Ex Vivo ◽  
Lipid Peroxides ◽  
Erythroid Differentiation ◽  
Conditional Knockout ◽  
Erythroleukemia Cells ◽  
Vitro Model ◽  
Mouse Erythroleukemia

Among the eight human glutathione peroxidase isoforms, glutathione peroxidase 4 (GPX4) is the only enzyme capable of reducing complex lipid peroxides to the corresponding alcohols. In mice, corruption of the Gpx4 gene leads to embryonic lethality and more detailed expression silencing studies have implicated the enzyme in several physiological processes (e.g., embryonal cerebrogenesis, neuronal function, male fertility). Experiments with conditional knockout mice, in which expression of the Gpx4 gene was silenced in erythroid precursors, indicated a role of Gpx4 in erythropoiesis. To test this hypothesis in a cellular in vitro model we transfected mouse erythroleukemia cells with a Gpx4 siRNA construct and followed the expression kinetics of erythropoietic gene products. Our data indicate that Gpx4 is expressed at high levels in mouse erythroleukemia cells and that expression silencing of the Gpx4 gene delays in vitro erythropoiesis. However, heterozygous expression of a catalytically inactive Gpx4 mutant (Gpx4+/Sec46Ala) did not induce a defective erythropoietic phenotype in different in vivo and ex vivo models. These data suggest that Gpx4 plays a role in erythroid differentiation of mouse erythroleukemia cells but that heterozygous expression of a catalytically inactive Gpx4 is not sufficient to compromise in vivo and ex vivo erythropoiesis.

scholarly journals Role of RIPK1 in SMAC mimetics-induced apoptosis in primary human HIV-infected macrophages

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ramon Edwin Caballero ◽  
Simon Xin Min Dong ◽  
Niranjala Gajanayaka ◽  
Hamza Ali ◽  
Edana Cassol ◽  
...  
Keyword(s):  
Cell Death ◽  
Hiv Infection ◽  
Ex Vivo ◽  
Laboratory Strain ◽  
Interacting Protein ◽  
Heat Stable Antigen ◽  
Smac Mimetics ◽  
Induced Apoptosis

AbstractMacrophages serve as viral reservoirs due to their resistance to apoptosis and HIV-cytopathic effects. We have previously shown that inhibitor of apoptosis proteins (IAPs) confer resistance to HIV-Vpr-induced apoptosis in normal macrophages. Herein, we show that second mitochondrial activator of caspases (SMAC) mimetics (SM) induce apoptosis of monocyte-derived macrophages (MDMs) infected in vitro with a R5-tropic laboratory strain expressing heat stable antigen, chronically infected U1 cells, and ex-vivo derived MDMs from HIV-infected individuals. To understand the mechanism governing SM-induced cell death, we show that SM-induced cell death of primary HIV-infected macrophages was independent of the acquisition of M1 phenotype following HIV infection of macrophages. Instead, SM-induced cell death was found to be mediated by IAPs as downregulation of IAPs by siRNAs induced cell death of HIV-infected macrophages. Moreover, HIV infection caused receptor interacting protein kinase-1 (RIPK1) degradation which in concert with IAP1/2 downregulation following SM treatment may result in apoptosis of macrophages. Altogether, our results show that SM selectively induce apoptosis in primary human macrophages infected in vitro with HIV possibly through RIPK1. Moreover, modulation of the IAP pathways may be a potential strategy for selective killing of HIV-infected macrophages in vivo.

scholarly journals Cloning and characterization of hELD/OSA1, a novel BRG1 interacting protein

2002 ◽  
Vol 364 (1) ◽  
pp. 255-264 ◽  
Author(s):  
Adam F.L. HURLSTONE ◽  
Ivan A. OLAVE ◽  
Nick BARKER ◽  
Mascha van NOORT ◽  
Hans CLEVERS
Keyword(s):  
Protein A ◽  
The Other ◽  
Dna Binding Domain ◽  
Related Protein ◽  
Related Gene ◽  
Human Homologue ◽  
Interacting Protein

A highly conserved multisubunit enzymic complex, SWI/SNF, participates in the regulation of eukaryote gene expression through its ability to remodel chromatin. While a single component of SWI/SNF, Swi2 or a related protein, can perform this function in vitro, the other components appear to modulate the activity and specificity of the complex in vivo. Here we describe the cloning of hELD/OSA1, a 189KDa human homologue of Drosophila Eld/Osa protein, a constituent of Drosophila SWI/SNF. By comparing conserved peptide sequences in Eld/Osa homologues we define three domains common to all family members. A putative DNA binding domain, or ARID (AT-rich DNA-interacting domain), may function in targetting SWI/SNF to chromatin. Two other domains unique to Eld/Osa proteins, EHD1 and EHD2, map to the C-teminus. We show that EHD2 mediates binding to Brahma-related gene 1 (BRG1), a human homologue of yeast Swi2. EHD1 and EHD2 also appear capable of interacting with each other. Using an antibody raised against EHD2 of hELD/OSA1, we detected Eld/Osa1 in endogenous SWI/SNF complexes derived from mouse brain.

scholarly journals A functional genetic screen identifies Aurora kinase b as a critical regulator of Sox9-positive embryonic lung progenitor cells

Development ◽  
2021 ◽  
Author(s):  
Ah-Cann C ◽  
Wimmer VC ◽  
Weeden CE ◽  
Marceaux C ◽  
Law CW ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Ex Vivo ◽  
Aurora Kinase ◽  
Postnatal Growth ◽  
Branching Morphogenesis ◽  
Genetic Screen ◽  
Conditional Knockout ◽  
Embryonic Lung ◽  
Aurora Kinase B

Development of a branching tree in the embryonic lung is critical for the formation of a fully mature functional lung at birth. Sox9+ cells present at the tip of the primary embryonic lung endoderm are multipotent cells responsible for branch formation and elongation. We performed a genetic screen and identified Aurora kinase b (Aurkb) as a critical regulator of Sox9+ cells ex vivo. In vivo conditional knockout studies confirmed that Aurkb was critical for lung development but was not necessary for postnatal growth and the repair of the adult lung after injury. Deletion of Aurkb in embryonic Sox9+ cells led to the formation of a stunted lung that retained the expression of Sox2 in the proximal airways, as well as Sox9 in the distal tips. While we found no change in cell polarity, we showed that loss of Aurkb or chemical inhibition of Aurkb induced a block of Sox9+ cells in G2/M, likely responsible for the lack of branch bifurcation. This work demonstrates the power of genetic screens in identifying novel regulators of Sox9+ progenitor cells and lung branching morphogenesis.

scholarly journals Inhibitor of apoptosis, IAP, genes play a critical role in the survival of HIV-infected macrophages

2019 ◽  
Author(s):  
Ashok Kumar ◽  
Ramon Edwin Hernandez Caballero ◽  
Simon Xin Min Dong ◽  
Niranjala Gajanayaka ◽  
Hamza Ali ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Critical Role ◽  
Laboratory Strain ◽  
Inhibitor Of Apoptosis ◽  
Viral Reservoirs ◽  
Interacting Protein ◽  
Heat Stable Antigen ◽  
Induced Apoptosis

Latent viral reservoirs of HIV-1 that persist despite antiretroviral therapy (ART) are major barriers for a successful cure. Macrophages serve as viral reservoirs due to their resistance to apoptosis and HIV-cytopathic effects. We have previously shown that inhibitor of apoptosis proteins (IAPs) confer resistance to HIV-Vpr-induced apoptosis in normal macrophages. Herein, we show that second mitochondrial activator of caspases (SMAC)-mimetics (SM) specifically induce apoptosis of monocyte-derived macrophages (MDMs) infected in vitro with a R5-tropic laboratory strain expressing heat stable antigen, and GFP-expressing HIV, chronically infected U1 cells, and ex-vivo derived MDMs from naïve and ART-treated HIV patients. SM-induced cell death was found to be mediated by IAPs using IAP siRNAs, was independent of endogenously produced TNFα and was attributed to the concomitant downregulation of IAP-1/2 and the receptor interacting protein kinase-1 degradation following HIV infection. Altogether, modulation of the IAP pathways may be a potential strategy for selective killing of HIV-infected macrophages in vivo.

scholarly journals LncEGFL7OS regulates human angiogenesis by interacting with MAX at the EGFL7/miR-126 locus

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Qinbo Zhou ◽  
Bo Yu ◽  
Chastain Anderson ◽  
Zhan-Peng Huang ◽  
Jakub Hanus ◽  
...  
Keyword(s):  
Therapeutic Potential ◽  
Ex Vivo ◽  
Bidirectional Promoter ◽  
Interacting Protein ◽  
Sprouting Angiogenesis ◽  
Pathway Activation ◽  
Opposite Strand ◽  
Ets Factors

In an effort to identify human endothelial cell (EC)-enriched lncRNAs,~500 lncRNAs were shown to be highly restricted in primary human ECs. Among them, lncEGFL7OS, located in the opposite strand of the EGFL7/miR-126 gene, is regulated by ETS factors through a bidirectional promoter in ECs. It is enriched in highly vascularized human tissues, and upregulated in the hearts of dilated cardiomyopathy patients. LncEGFL7OS silencing impairs angiogenesis as shown by EC/fibroblast co-culture, in vitro/in vivo and ex vivo human choroid sprouting angiogenesis assays, while lncEGFL7OS overexpression has the opposite function. Mechanistically, lncEGFL7OS is required for MAPK and AKT pathway activation by regulating EGFL7/miR-126 expression. MAX protein was identified as a lncEGFL7OS-interacting protein that functions to regulate histone acetylation in the EGFL7/miR-126 promoter/enhancer. CRISPR-mediated targeting of EGLF7/miR-126/lncEGFL7OS locus inhibits angiogenesis, inciting therapeutic potential of targeting this locus. Our study establishes lncEGFL7OS as a human/primate-specific EC-restricted lncRNA critical for human angiogenesis.

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

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