scholarly journals The Gridlock transcriptional repressor impedes vertebrate heart regeneration by restricting expression of lysine methyltransferase

Development ◽  
2020 ◽  
Vol 147 (18) ◽  
pp. dev190678
Author(s):  
Peilu She ◽  
Huifang Zhang ◽  
Xiangwen Peng ◽  
Jianjian Sun ◽  
Bangjun Gao ◽  
...  
Keyword(s):  
Transcriptional Repression ◽  
Transcriptional Repressor ◽  
Heart Regeneration ◽  
Protein Levels ◽  
Helix Loop Helix ◽  
Lysine Methyltransferase ◽  
Heart Injury ◽  
Potential Strategy ◽  
Phosphorylated Stat3 ◽  
Zebrafish Heart

ABSTRACTTeleost zebrafish and neonatal mammalian hearts exhibit the remarkable capacity to regenerate through dedifferentiation and proliferation of pre-existing cardiomyocytes (CMs). Although many mitogenic signals that stimulate zebrafish heart regeneration have been identified, transcriptional programs that restrain injury-induced CM renewal are incompletely understood. Here, we report that mutations in gridlock (grl; also known as hey2), encoding a Hairy-related basic helix-loop-helix transcriptional repressor, enhance CM proliferation and reduce fibrosis following damage. In contrast, myocardial grl induction blunts CM dedifferentiation and regenerative responses to heart injury. RNA sequencing analyses uncover Smyd2 lysine methyltransferase (KMT) as a key transcriptional target repressed by Grl. Reduction in Grl protein levels triggered by injury induces smyd2 expression at the wound myocardium, enhancing CM proliferation. We show that Smyd2 functions as a methyltransferase and modulates the Stat3 methylation and phosphorylation activity. Inhibition of the KMT activity of Smyd2 reduces phosphorylated Stat3 at cardiac wounds, suppressing the elevated CM proliferation in injured grl mutant hearts. Our findings establish an injury-specific transcriptional repression program in governing CM renewal during heart regeneration, providing a potential strategy whereby silencing Grl repression at local regions might empower regeneration capacity to the injured mammalian heart.

scholarly journals HES-1 Repression of Differentiation and Proliferation in PC12 Cells: Role for the Helix 3-Helix 4 Domain in Transcription Repression

2000 ◽  
Vol 20 (16) ◽  
pp. 6170-6183 ◽  
Author(s):  
Paul Castella ◽  
Shoji Sawai ◽  
Keiko Nakao ◽  
John A. Wagner ◽  
Michael Caudy
Keyword(s):  
Dna Binding ◽  
Pc12 Cells ◽  
Transcriptional Repression ◽  
Kinase Inhibitor ◽  
Induced Differentiation ◽  
Transcription Repression ◽  
Protein Levels ◽  
Helix Loop Helix ◽  
Neurite Formation ◽  
Differentiation And Proliferation

ABSTRACT HES-1 is a Hairy-related basic helix-loop-helix protein with three evolutionarily conserved regions known to define its function as a transcription repressor. The basic region, helix-loop-helix domain, and WRPW motif have been characterized for their molecular function in DNA binding, dimer formation, and corepressor recruitment, respectively. In contrast, the function conferred by a fourth conserved region, the helix 3-helix 4 (H-3/4) domain, is not known. To better understand H-3/4 domain function, we expressed HES-1 variants under tetracycline-inducible control in PC12 cells. As expected, the induced expression of moderate levels of wild-type HES-1 in PC12 cells strongly inhibited nerve growth factor-induced differentiation. This repression was dependent on the H-3/4 domain. Unexpectedly, expression of HES-1 also arrested cell growth, an effect that could be reversed upon down regulation of HES-1. Concomitant with growth arrest, there was a strong reduction in bromodeoxyuridine incorporation and PCNA protein levels, although not in cyclin D1 expression. Expression of a HES-1 protein carrying the H-3/4 domain, but not the WRPW domain, still partially inhibited both proliferation and differentiation. Transcription assays in PC12 cells directly demonstrated that the H-3/4 domain can mediate DNA-binding-dependent transcription repression, even in the absence of corepressor recruitment by the WRPW motif. HES-1 expression strongly repressed transcription of the p21 cip1promoter, a cyclin–cyclin-dependent kinase inhibitor up regulated during NGF-induced differentiation, and the H-3/4 domain is necessary for this repression. Thus, the H-3/4 domain of HES-1 contributes to transcription repression independently of WRPW function, inhibits neurite formation, and facilitates two distinct and previously uncharacterized roles for HES-1: the inhibition of cell proliferation and the direct transcriptional repression of the NGF-induced gene,p21.

scholarly journals Estrogen accelerates heart regeneration by promoting inflammatory responses in zebrafish

2019 ◽  
Author(s):  
Shisan Xu ◽  
Fangjing Xie ◽  
Samane Fallah ◽  
Fatemeh Babaei ◽  
Lina Zhu ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Specific Protein ◽  
Model System ◽  
Sexual Differences ◽  
Heart Regeneration ◽  
Heart Injury ◽  
Underlying Mechanisms ◽  
Female Specific ◽  
Estrogen Antagonist ◽  
Zebrafish Heart

AbstractSexual differences are observed in the onset and prognosis of human cardiovascular diseases, but the underlying mechanisms are not clear. Here, we report that zebrafish heart regeneration is faster in females, can be accelerated by estrogen and suppressed by estrogen-antagonist tamoxifen. Injuries to the heart, but not other tissues, increased plasma estrogen level and expression of estrogen receptors, especiallyesr2a, in zebrafish hearts. The resulting endocrine disruption induces the expression of female-specific protein vitellogenin in male zebrafish. Transcriptomic analyses suggested heart injuries triggered more pronounced immune and inflammatory responses in females. These responses, previously shown to enhance heart regeneration, could be enhanced by estrogen treatment in males and reduced by tamoxifen in female. Furthermore, a brief exposure to estrogen could precondition zebrafish for an accelerated heart regeneration. Altogether, this study reveals that heart regeneration is modulated by an estrogen-inducible inflammatory response to heart injury. These findings elucidate a previously unknown layer of control in zebrafish heart regeneration and provides a new model system for the study of sexual differences in human cardiac repair.

scholarly journals SIN3-dependent transcriptional repression by interaction with the Mad1 DNA-binding protein.

1996 ◽  
Vol 16 (8) ◽  
pp. 4215-4221 ◽  
Author(s):  
M M Kasten ◽  
D E Ayer ◽  
D J Stillman
Keyword(s):  
Transcriptional Repression ◽  
Leucine Zipper ◽  
Protein A ◽  
Transcriptional Repressor ◽  
Dna Binding Protein ◽  
Negative Regulator ◽  
Helix Loop Helix ◽  
N Terminus ◽  
Number Of Genes ◽  
Two Hybrid

The SIN3 gene in Saccharomyces cerevisiae encodes a negative regulator of transcription of a large number of genes. Mouse homologs of SIN3 have been identified through screens for proteins interacting with the mammalian Mad1 protein, a transcriptional repressor. We find that yeast Sin3 (ySin3) interacts with Madl and that, as for mouse Sin3, the N terminus of Mad1 interacts with the PAH2 domain of ySin3. Although Mad1 (a basic helix-loop-helix leucine zipper [bHLH-Zip) protein) forms a heterodimer with the Max bHLH-Zip protein, LexA-Mad1 and VP16-Max do not activate transcription of a reporter gene in a two-hybrid assay. This failure in activation is due to direct repression by ySin3, as LexA-Mad1 and VP16-Max are able to activate the two-hybrid reporter in a sin3 mutant. This inhibition of activation by LexA-Mad1 and VP16-Max requires the PAH2 domain of ySin3 and the N-terminal interaction region of Mad1. These data demonstrate that ySin3 functions as a transcriptional repressor by being brought to promoters by interacting with proteins bound to DNA.

scholarly journals Loss of FOXF1 expression promotes human lung-resident mesenchymal stromal cell migration via ATX/LPA/LPA1 signaling axis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Pengxiu Cao ◽  
Natalie M. Walker ◽  
Russell R. Braeuer ◽  
Serina Mazzoni-Putman ◽  
Yoshiro Aoki ◽  
...  
Keyword(s):  
Mesenchymal Stromal Cells ◽  
Stromal Cells ◽  
Transcriptional Repression ◽  
Inflammatory Responses ◽  
Transcriptional Repressor ◽  
Boyden Chamber ◽  
Signaling Axis ◽  
Lpa1 Receptor ◽  
Human Adult Lung ◽  
Upregulated Genes

AbstractForkhead box F1 (FOXF1) is a lung embryonic mesenchyme-associated transcription factor that demonstrates persistent expression into adulthood in mesenchymal stromal cells. However, its biologic function in human adult lung-resident mesenchymal stromal cells (LR-MSCs) remain to be elucidated. Here, we demonstrate that FOXF1 expression acts as a restraint on the migratory function of LR-MSCs via its role as a novel transcriptional repressor of autocrine motility-stimulating factor Autotaxin (ATX). Fibrotic human LR-MSCs demonstrated lower expression of FOXF1 mRNA and protein, compared to non-fibrotic controls. RNAi-mediated FOXF1 silencing in LR-MSCs was associated with upregulation of key genes regulating proliferation, migration, and inflammatory responses and significantly higher migration were confirmed in FOXF1-silenced LR-MSCs by Boyden chamber. ATX is a secreted lysophospholipase D largely responsible for extracellular lysophosphatidic acid (LPA) production, and was among the top ten upregulated genes upon Affymetrix analysis. FOXF1-silenced LR-MSCs demonstrated increased ATX activity, while mFoxf1 overexpression diminished ATX expression and activity. The FOXF1 silencing-induced increase in LR-MSC migration was abrogated by genetic and pharmacologic targeting of ATX and LPA1 receptor. Chromatin immunoprecipitation analyses identified three putative FOXF1 binding sites in the 1.5 kb ATX promoter which demonstrated transcriptional repression of ATX expression. Together these findings identify FOXF1 as a novel transcriptional repressor of ATX and demonstrate that loss of FOXF1 promotes LR-MSC migration via the ATX/LPA/LPA1 signaling axis.

scholarly journals LOXL1 confers antiapoptosis and promotes gliomagenesis through stabilizing BAG2

2020 ◽  
Vol 27 (11) ◽  
pp. 3021-3036 ◽  
Author(s):  
Hua Yu ◽  
Jun Ding ◽  
Hongwen Zhu ◽  
Yao Jing ◽  
Hu Zhou ◽  
...  
Keyword(s):  
Molecular Chaperone ◽  
Glioma Cell ◽  
Lysyl Oxidase ◽  
The Cancer Genome Atlas ◽  
Loss Of Function ◽  
Protein Levels ◽  
Important Mediator ◽  
Cancer Genome Atlas ◽  
Potential Strategy ◽  
Glioma Progression

Abstract The lysyl oxidase (LOX) family is closely related to the progression of glioma. To ensure the clinical significance of LOX family in glioma, The Cancer Genome Atlas (TCGA) database was mined and the analysis indicated that higher LOXL1 expression was correlated with more malignant glioma progression. The functions of LOXL1 in promoting glioma cell survival and inhibiting apoptosis were studied by gain- and loss-of-function experiments in cells and animals. LOXL1 was found to exhibit antiapoptotic activity by interacting with multiple antiapoptosis modulators, especially BAG family molecular chaperone regulator 2 (BAG2). LOXL1-D515 interacted with BAG2-K186 through a hydrogen bond, and its lysyl oxidase activity prevented BAG2 degradation by competing with K186 ubiquitylation. Then, we discovered that LOXL1 expression was specifically upregulated through the VEGFR-Src-CEBPA axis. Clinically, the patients with higher LOXL1 levels in their blood had much more abundant BAG2 protein levels in glioma tissues. Conclusively, LOXL1 functions as an important mediator that increases the antiapoptotic capacity of tumor cells, and approaches targeting LOXL1 represent a potential strategy for treating glioma. In addition, blood LOXL1 levels can be used as a biomarker to monitor glioma progression.

scholarly journals Inhibition of let-7c Regulates Cardiac Regeneration after Cryoinjury in Adult Zebrafish

2019 ◽  
Vol 6 (2) ◽  
pp. 16 ◽  
Author(s):  
Suneeta Narumanchi ◽  
Karri Kalervo ◽  
Sanni Perttunen ◽  
Hong Wang ◽  
Katariina Immonen ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Cardiac Regeneration ◽  
Nuclear Antigen ◽  
Heart Regeneration ◽  
Adult Zebrafish ◽  
Tissue Samples ◽  
Micro Rnas ◽  
Proliferating Cell ◽  
Zebrafish Heart

The let-7c family of micro-RNAs (miRNAs) is expressed during embryonic development and plays an important role in cell differentiation. We have investigated the role of let-7c in heart regeneration after injury in adult zebrafish. let-7c antagomir or scramble injections were given at one day after cryoinjury (1 dpi). Tissue samples were collected at 7 dpi, 14 dpi and 28 dpi and cardiac function was assessed before cryoinjury, 1 dpi, 7 dpi, 14 dpi and 28 dpi. Inhibition of let-7c increased the rate of fibrinolysis, increased the number of proliferating cell nuclear antigen (PCNA) positive cardiomyocytes at 7 dpi and increased the expression of the epicardial marker raldh2 at 7 dpi. Additionally, cardiac function measured with echocardiography recovered slightly more rapidly after inhibition of let-7c. These results reveal a beneficial role of let-7c inhibition in adult zebrafish heart regeneration.

scholarly journals A Systematic Exposition of Methods used for Quantification of Heart Regeneration after Apex Resection in Zebrafish

Cells ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 548 ◽  
Author(s):  
Helene Juul Belling ◽  
Wolfgang Hofmeister ◽  
Ditte Caroline Andersen
Keyword(s):  
Human Heart ◽  
Quantitative Methods ◽  
Heart Function ◽  
Heart Regeneration ◽  
Cardiomyocyte Proliferation ◽  
Ability To Regenerate ◽  
Specific Proteins ◽  
Heart Injury ◽  
Whole Heart ◽  
Study Designs

Myocardial infarction (MI) is a worldwide condition that affects millions of people. This is mainly caused by the adult human heart lacking the ability to regenerate upon injury, whereas zebrafish have the capacity through cardiomyocyte proliferation to fully regenerate the heart following injury such as apex resection (AR). But a systematic overview of the methods used to evidence heart regrowth and regeneration in the zebrafish is lacking. Herein, we conducted a systematical search in Embase and Pubmed for studies on heart regeneration in the zebrafish following injury and identified 47 AR studies meeting the inclusion criteria. Overall, three different methods were used to assess heart regeneration in zebrafish AR hearts. 45 out of 47 studies performed qualitative (37) and quantitative (8) histology, whereas immunohistochemistry for various cell cycle markers combined with cardiomyocyte specific proteins was used in 34 out of 47 studies to determine cardiomyocyte proliferation qualitatively (6 studies) or quantitatively (28 studies). For both methods, analysis was based on selected heart sections and not the whole heart, which may bias interpretations. Likewise, interstudy comparison of reported cardiomyocyte proliferation indexes seems complicated by distinct study designs and reporting manners. Finally, six studies performed functional analysis to determine heart function, a hallmark of human heart injury after MI. In conclusion, our data implies that future studies should consider more quantitative methods eventually taking the 3D of the zebrafish heart into consideration when evidencing myocardial regrowth after AR. Furthermore, standardized guidelines for reporting cardiomyocyte proliferation and sham surgery details may be considered to enable inter study comparisons and robustly determine the effect of given genes on the process of heart regeneration.

scholarly journals Functional Domains of c-myc Promoter Binding Protein 1 Involved in Transcriptional Repression and Cell Growth Regulation

1999 ◽  
Vol 19 (4) ◽  
pp. 2880-2886 ◽  
Author(s):  
Asish K. Ghosh ◽  
Robert Steele ◽  
Ratna B. Ray
Keyword(s):  
Amino Acids ◽  
Cell Growth ◽  
Dna Binding ◽  
Transcriptional Repression ◽  
Growth Regulation ◽  
Transcriptional Repressor ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Repressor Activity

ABSTRACT We initially identified c-myc promoter binding protein 1 (MBP-1), which negatively regulates c-myc promoter activity, from a human cervical carcinoma cell expression library. Subsequent studies on the biological role of MBP-1 demonstrated induction of cell death in fibroblasts and loss of anchorage-independent growth, reduced invasive ability, and tumorigenicity of human breast carcinoma cells. To investigate the potential role of MBP-1 as a transcriptional regulator, a chimeric protein containing MBP-1 fused to the DNA binding domain of the yeast transactivator factor GAL4 was constructed. This fusion protein exhibited repressor activity on the herpes simplex virus thymidine kinase promoter via upstream GAL4 DNA binding sites. Structure-function analysis of mutant MBP-1 in the context of the GAL4 DNA binding domain revealed that MBP-1 transcriptional repressor domains are located in the N terminus (amino acids 1 to 47) and C terminus (amino acids 232 to 338), whereas the activation domain lies in the middle (amino acids 140 to 244). The N-terminal domain exhibited stronger transcriptional repressor activity than the C-terminal region. When the N-terminal repressor domain was transferred to a potent activator, transcription was strongly inhibited. Both of the repressor domains contained hydrophobic regions and had an LXVXL motif in common. Site-directed mutagenesis in the repressor domains indicated that the leucine residues in the LXVXL motif are required for transcriptional repression. Mutation of the leucine residues in the common motif of MBP-1 also abrogated the repressor activity on the c-mycpromoter. In addition, the leucine mutant forms of MBP-1 failed to suppress cell growth in fibroblasts like wild-type MBP-1. Taken together, our results indicate that MBP-1 is a complex cellular factor containing multiple transcriptional regulatory domains that play an important role in cell growth regulation.

Abstract 706: Changes in Translational Efficacy During Zebrafish Heart Regeneration

2019 ◽  
Vol 125 (Suppl_1) ◽  
Author(s):  
Joseph A Goldman ◽  
Ariel Bazzini ◽  
Antonio Giraldez ◽  
Kenneth Poss
Keyword(s):  
Heart Regeneration ◽  
Zebrafish Heart
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