Abstract 1839: MicroRNA-499 Promotes the Differentiation of Cardiac Progenitor Cells into Myocytes

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Toru Hosoda ◽  
Konrad Urbanek ◽  
Adriana Bastos Carvalho ◽  
Claudia Bearzi ◽  
Silvana Bardelli ◽  
...  
Keyword(s):  
Gap Junctions ◽  
Progenitor Cells ◽  
Target Genes ◽  
Brdu Incorporation ◽  
Cardiac Progenitor Cells ◽  
Partial Recovery ◽  
Rt Pcr ◽  
Protein Levels ◽  
Cell Proliferation And Differentiation ◽  
Reporter Assays

Myocardial regeneration mediated by cardiac progenitor cells (CPCs) results in the partial recovery of the infarcted heart but the newly formed myocytes within the necrotic tissue have fetal-neonatal characteristics. In contrast, CPC activation in the remote viable myocardium results in the formation of mature myocytes, suggesting that CPC differentiation is conditioned by the surrounding cells. Thus, the hypothesis is raised that microRNAs (miRs) that are highly expressed in myocytes and are absent in CPCs, may translocate through gap junctions to adjacent CPCs promoting their differentiation. By employing miR array and Q-RT-PCR, miR-499 was found to be ~500-fold more expressed in myocytes than CPCs. Additionally, we demonstrated that miR-499 translocates from neighboring cells to CPCs through the formation of gap junctions. The translocated miR-499 was functional and repressed the expression of target genes. Among 200 putative targets of miR-499, we have elected to study Sox6 and Rod1. The validation of these putative miR-499-targets was obtained by reporter assays; cells transfected with miR-499 together with plasmids carrying luciferase and the 3′-UTR region of Sox6 or Rod1 show the expected decrease in luciferase activity. Transcripts of Sox6 and Rod1 were measured by Q-RT-PCR in myocytes and CPCs; Sox6 mRNA was 2-fold higher and Rod1 mRNA was 98% lower in myocytes than CPCs. However, the protein levels of Sox6 and Rod1 were significantly lower in myocytes than CPCs suggesting that miR-499 promotes degradation and/or inhibition of translation of these target genes. To document miR-499 function, CPCs were transfected with a miR-499-expression vector and cell proliferation and differentiation were evaluated 3 days later. BrdU incorporation decreased 60% and the cells displayed a marked upregulation of the myocyte-specific transcription factors Nkx2.5 and MEF2C. Similar results were obtained when Sox6 and Rod1 were selectively blocked with siRNA. In both cases, the number of Nkx2.5- and MEF2C-positive cells increased 2–3-fold. Thus, our data indicate that miR-499 translocates via gap junction from myocytes to CPCs where miR-499 is a crucial modulator of the differentiation of CPCs into cardiomyocytes through the repression of Sox6 and Rod1.

scholarly journals Gremlin2 Regulates the Differentiation and Function of Cardiac Progenitor Cells via the Notch Signaling Pathway

2018 ◽  
Vol 47 (2) ◽  
pp. 579-589 ◽  
Author(s):  
Wei Li ◽  
Yaojun Lu ◽  
Ruijuan Han ◽  
Qiang Yue ◽  
Xiurong Song ◽  
...  
Keyword(s):  
Mouse Model ◽  
Progenitor Cells ◽  
Left Ventricular ◽  
Cardiac Repair ◽  
Cardiac Progenitor Cells ◽  
Cardiomyocyte Differentiation ◽  
Rt Pcr ◽  
And Function

Background/Aims: The transplantation of cardiac progenitor cells (CPCs) improves neovascularization and left ventricular function after myocardial infarction (MI). The bone morphogenetic protein antagonist Gremlin 2 (Grem2) is required for early cardiac development and cardiomyocyte differentiation. The present study examined the role of Grem2 in CPC differentiation and cardiac repair. Methods: To determine the role of Grem 2 during CPC differentiation, c-Kit+ CPCs were cultured in differentiation medium for different times, and Grem2, Notch1 and Jagged1 expression was determined by RT-PCR and western blotting. Short hairpin RNA was used to silence Grem2 expression, and the expression of cardiomyocyte surface markers was assessed by RT-PCR and immunofluorescence staining. In vivo experiments were performed in a mouse model of left anterior descending coronary artery ligation-induced MI. Results: CPC differentiation upregulated Grem2 expression and activated the Notch1 pathway. Grem2 knockdown inhibited cardiomyocyte differentiation, and this effect was similar to that of Notch1 pathway inhibition in vitro. Jagged1 overexpression rescued the effects of Grem2 silencing. In vivo, Grem2 silencing abolished the protective effects of CPC injection on cardiac fibrosis and function. Conclusions: Grem2 regulates CPC cardiac differentiation by modulating Notch1 signaling. Grem2 enhances the protective effect of CPCs on heart function in a mouse model of MI, suggesting its potential as the rapeutic protein for cardiac repair.

scholarly journals Pre-Clinical Efficacy of Co-Targeting GFI1/KDM1A and BRD4 or JAK1/2 Against AML and Post-MPN Secondary AML Blast Progenitor Cells

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 27-27
Author(s):  
Warren Fiskus ◽  
Christopher Peter Mill ◽  
Christine Birdwell ◽  
Bernardo H Lara ◽  
Prithviraj Bose ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Research Funding ◽  
Target Genes ◽  
Amine Oxidase ◽  
Colony Growth ◽  
Protein Domain ◽  
Rna Seq ◽  
Protein Levels ◽  
Gene Sets ◽  
Induced Apoptosis

Transcriptional regulators (TFs) involved in cell-growth, differentiation and survival of AML stem/progenitor cells (LSCs) include RUNX1, PU.1, CEBPα, c-Myb and c-Myc. LSD1 (KDM1A) is an FAD-dependent amine-oxidase that demethylates mono and dimethyl histone H3 lysine 4 (H3K4Me1 and H3K4Me2). LSD1 is part of the repressor complexes involving GFI1, CoREST and HDAC1/2, that regulate active super-enhancers/enhancers (SEs/Es) and their target genes, mediating transcriptional repression and differentiation block in LSCs. GFI1 is a zinc-finger transcriptional repressor involved in AML development and differentiation. GFI1 contains an N-terminal domain through which it binds to the CoREST/LSD1/HDAC1/2 complex to regulate differentiation in LSCs. CRISPR-suppressor scanning revealed that enzymatic activity of LSD1 was not required for LSC differentiation, instead disruption of binding of LSD1 to GFI1 and CoREST induced differentiation in LSCs. LSD1 and GFI1 expression correlates with worse prognosis in MDS/AML. In present studies, we demonstrate first-time ever that knockout (KO) or degradation of LSD1 utilizing CRISPR-Cas9 or LSD1-FKBP12(F36V) and dTAG-13, respectively, disrupted LSD1-binding to GFI1/1B and CoREST, inhibiting colony growth and inducing differentiation markers (CD86 and CD11b) and morphologic differentiation of AML and post-MPN sAML blast progenitor cells (BPCs). CRISPR-mediated knockout of LSD1 in the AML OCI-AML5 and sAML SET2 cells significantly increased the permissive H3K4Me2/3-marked chromatin, reduced H3K27Ac occupancy at SEs/Es (by ChIP-Seq), especially of c-Myc and CDK6, as well as repressed DNMT1, CoREST, c-Myc, CDK6, and c-KIT, while inducing GFI1, PU.1, CEBPα, p21, CD11b, and CD86 levels (log2 -fold change by RNA-Seq and by Western analyses). This correlated with growth inhibition, % differentiation and apoptosis of AML and sAML cells. CRISPR-mediated GFI1-KO ± the irreversible LSD1 inhibitor (LSD1i) (INCB059872, INCB), repressed GFI1 levels, yet enhanced expressions of PU.1, p21 and CD11b and significantly increased % morphologic differentiation. Treatment with INCB (0.25 to 1.0 µM) also disrupted binding of LSD1 to GFI1 and to CoREST, increased GFI1/1B and PU.1 and repressed c-Myc protein levels, while significantly inhibiting colony growth, inducing differentiation and loss of viability of AML and post-MPN sAML (SET2 and HEL92.1.7) cells, as well as patient-derived AML and post-MPN sAML blasts (p < 0.01). Following INCB treatment, ATAC-Seq analysis demonstrated gained peaks in GFI1 and PU.1-target genes. Following H3K27Ac ChIP-seq analysis rank-ordering of SEs (ROSE) plot highlighted active SEs of RUNX1, GFI1, BCL2, PU.1, IRF8 and SMYD3, accompanied by increased H3K27Ac occupancy at the chromatin of GFI1 and PU.1 targets. Notably, INCB treatment also increased BRD4 occupancy, especially at the GFI1 and PU.1-target genes. RNA-Seq analysis showed that INCB treatment perturbed mRNA expressions, with positive normalized enrichment scores (NES) for interferon α, inflammatory-response, GFI1-targets and E2F-target gene-sets, and negative NES for c-Myc-targets and oxidative-phosphorylation gene-sets. RNA-Seq analyses of INCB-treated compared to untreated OCI-AML5 and SET-2 cells also demonstrated log2 fold-increase in the mRNA expressions of GFI1, PU.1 and CEBPα target-genes. Utilizing a protein domain-scanning CRISPR-Cas9 sgRNA screen followed by LSD1i treatment, present studies also demonstrate co-dependencies, including BRD4, in AML cells. BET inhibitor (BETi) treatment also depleted LSD1 protein levels, and co-treatment with the BETi OTX015 and INCB induced synergistic lethality in AML and post-MPN sAML blasts (Combination Indices < 1.0). Pre-treatment with INCB re-sensitized JAKi-resistant sAML cells to ruxolitinib-induced apoptosis and BETi-resistant post-MPN sAML cells to BETi-induced apoptosis. Notably, co-treatment with INCB (1.5 mg/kg) and ruxolitinib (20 mg/kg) or OTX015 (50 mg/kg), administered orally for 21 days, compared to ruxolitinib alone or vehicle control, significantly reduced the sAML burden and improved survival of immune-depleted mice engrafted with luciferized sAML HEL92.1.7 xenografts (p < 0.01). Collectively, these findings support further pre-clinical development of LSD1i-based combinations with ruxolitinib and BETi against post-MPN sAML. Disclosures Bose: CTI BioPharma: Honoraria, Research Funding; NS Pharma: Research Funding; Celgene Corporation: Honoraria, Research Funding; Pfizer, Inc.: Research Funding; Constellation Pharmaceuticals: Research Funding; Astellas Pharmaceuticals: Research Funding; Blueprint Medicines Corporation: Honoraria, Research Funding; Promedior, Inc.: Research Funding; Incyte Corporation: Consultancy, Honoraria, Research Funding, Speakers Bureau; Kartos Therapeutics: Honoraria, Research Funding. Kadia:Incyte: Research Funding; Pulmotec: Research Funding; Cellenkos: Research Funding; Celgene: Research Funding; Amgen: Research Funding; Genentech: Honoraria, Research Funding; JAZZ: Honoraria, Research Funding; Cyclacel: Research Funding; Novartis: Honoraria; Ascentage: Research Funding; Astellas: Research Funding; Pfizer: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; Astra Zeneca: Research Funding; BMS: Honoraria, Research Funding. Verstovsek:CTI Biopharma Corp: Research Funding; AstraZeneca: Research Funding; Sierra Oncology: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Incyte Corporation: Consultancy, Research Funding; PharmaEssentia: Research Funding; Blueprint Medicines Corp: Research Funding; NS Pharma: Research Funding; Roche: Research Funding; Gilead: Research Funding; Protagonist Therapeutics: Research Funding; Promedior: Research Funding; Genentech: Research Funding; Celgene: Consultancy, Research Funding; ItalPharma: Research Funding.

Abstract 51: Nucleostemin Induced by Pim-1 Kinase Is Critical to Maintain Pluripotency and Enhance Regenerative Potential of Cardiac Progenitor Cells

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Nirmala Hariharan ◽  
Anya Y Joyo ◽  
Kaitlen M Samse ◽  
Daniele Avitabile ◽  
Brandi Bailey ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Shape Control ◽  
Kinase Inhibitor ◽  
Cardiac Regeneration ◽  
Stem Cell Marker ◽  
Cardiac Progenitor Cells ◽  
Protein Levels ◽  
Regulation Of Cell Cycle ◽  
Factor C

Myocardial regeneration and repair in response to injury are governed in part by cell survival, proliferation and pluripotency. Proliferation and survival in cardiac progenitor cells (CPCs) are mediated by Pim-1, a serine threonine kinase, and nucleostemin (NS), a nucleolar stress sensor protein. The role of NS in regulating CPC pluripotency and the molecular mechanism of NS induction and action is largely unknown. The hypothesis of the study is that NS, induced by Pim-1 mediated stabilization of transcription factor c-Myc is critical to maintain CPC pluripotency and inhibits senescence. NS and c-Myc protein levels are increased in cultured CPCs overexpressing Pim-1 (3.1 and 5.5 fold, p<0.01) while knockdown of Pim-1 using sh-RNA decreases c-Myc and NS expression (-60%, -54%, p<0.05), similar to effects mediated by a Pim-1 kinase inhibitor (p<0.01), indicating that Pim-1 regulates both c-Myc and NS. c-Myc is necessary and sufficient for NS regulation, as indicated by the increase (3.1 fold, p<0.01) and decrease (-60.2%, p<0.01) in NS expression upon lentiviral mediated over-expression or knockdown of c-Myc, respectively. Regulation of NS promoter by c-Myc is evident from loss of GFP expression and fluorescence following knock down of c-Myc in CPCs isolated from transgenic mice expressing eGFP driven by the NS promoter. The role of NS in regulating CPC pluripotency is determined by silencing NS. Change in morphology (flat, round cells vs spindle shape control CPCs), decreased expression of stem cell marker c-Kit (-55%, p<0.05), up-regulation of cell cycle inhibitors p53 and p16 (4.2, 3.8 fold, p<0.01) and decreased proliferation (p<0.05) result from loss of NS in CPCs, suggestive of increased senescence and loss of pluripotency. NS-mediated regulation of CPC senescence is p53 dependent, as silencing p53 reverses CPC morphology and pluripotency lost by NS depletion. In conclusion, NS which is induced downstream of Pim-1 kinase maintains pluripotency and enhances regenerative potential in CPCs. These findings are consistent with cumulative evidence that Pim-1 induced cardiac regeneration is mediated in part by NS, providing an additional mechanistic basis for benefits of genetic engineering with Pim-1 to enhance NS expression in cardiac stem cells.

scholarly journals Target genes of the largest human SWI/SNF complex subunit control cell growth

2011 ◽  
Vol 434 (1) ◽  
pp. 83-92 ◽  
Author(s):  
Hiroko Inoue ◽  
Stavros Giannakopoulos ◽  
Christopher N. Parkhurst ◽  
Tatsushi Matsumura ◽  
Evelyn A. Kono ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Growth ◽  
Target Genes ◽  
Control Cell ◽  
Cycle Phase ◽  
Chromatin Remodelling Complex ◽  
Baf Complex ◽  
Protein Levels ◽  
Hela Cell Lines ◽  
Reporter Assays

The largest subunit of the mammalian SWI/SNF-A or BAF (BRG1-associated factor) chromatin-remodelling complex is encoded by two related cDNAs hOsa1/BAF250a and hOsa2/BAF250b that are unique to the BAF complex and absent in the related PBAF (Polybromo BAF). hOsa/BAF250 has been shown to interact with transcriptional activators and bind to DNA suggesting that it acts to target the remodelling complex to chromatin. To better understand the functions of hOsa2, we established inducible stable HeLa cell lines over-expressing FLAG–hOsa2 or a derivative lacking the ARID (AT-rich interactive domain) DNA-binding domain. Immunopurification of complexes containing hOsa2 that was followed by mass spectrometry and immunoblotting demonstrated the presence of BRG1 and known BAFs, but not hOsa1 or hBRM. Deletion of the ARID did not compromise the integrity of the complex. Induction of hOsa2 expression caused impaired cell growth and accumulation of cells in the G0/G1 cell cycle phase. Elevated levels of the p53 and p21 proteins were detected in these cells while c-Myc mRNA and protein levels were found to decrease. Chromatin immunoprecipitation and reporter assays suggested that hOsa2 had a direct effect on c-myc and p21 promoter activity. Thus hOsa2 plays an important role in controlling genes regulating the cell cycle.

scholarly journals Validation of human microRNA target pathways enables evaluation of target prediction tools

2020 ◽  
Author(s):  
Fabian Kern ◽  
Lena Krammes ◽  
Karin Danz ◽  
Caroline Diener ◽  
Tim Kehl ◽  
...  
Keyword(s):  
Target Genes ◽  
Cell Model ◽  
Mirna Gene ◽  
Neuronal Cell ◽  
Target Prediction ◽  
Reporter Assay ◽  
Microrna Target ◽  
Protein Levels ◽  
Endogenous Protein ◽  
Reporter Assays

Abstract MicroRNAs are regulators of gene expression. A wide-spread, yet not validated, assumption is that the targetome of miRNAs is non-randomly distributed across the transcriptome and that targets share functional pathways. We developed a computational and experimental strategy termed high-throughput miRNA interaction reporter assay (HiTmIR) to facilitate the validation of target pathways. First, targets and target pathways are predicted and prioritized by computational means to increase the specificity and positive predictive value. Second, the novel webtool miRTaH facilitates guided designs of reporter assay constructs at scale. Third, automated and standardized reporter assays are performed. We evaluated HiTmIR using miR-34a-5p, for which TNF- and TGFB-signaling, and Parkinson's Disease (PD)-related categories were identified and repeated the pipeline for miR-7-5p. HiTmIR validated 58.9% of the target genes for miR-34a-5p and 46.7% for miR-7-5p. We confirmed the targeting by measuring the endogenous protein levels of targets in a neuronal cell model. The standardized positive and negative targets are collected in the new miRATBase database, representing a resource for training, or benchmarking new target predictors. Applied to 88 target predictors with different confidence scores, TargetScan 7.2 and miRanda outperformed other tools. Our experiments demonstrate the efficiency of HiTmIR and provide evidence for an orchestrated miRNA-gene targeting.

HIF-1α-targeted pathways are activated by heat acclimation and contribute to acclimation-ischemic cross-tolerance in the heart

2005 ◽  
Vol 23 (1) ◽  
pp. 79-88 ◽  
Author(s):  
Alina Maloyan ◽  
Luba Eli-Berchoer ◽  
Gregg L. Semenza ◽  
Gary Gerstenblith ◽  
Michael D. Stern ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Target Genes ◽  
Hypoxia Inducible Factor ◽  
Heat Acclimation ◽  
Heme Oxygenase 1 ◽  
Mrna Levels ◽  
Rt Pcr ◽  
Cross Tolerance ◽  
Protein Levels ◽  
Rat Hearts

Hypoxia-inducible factor-1 (HIF-1) is a key regulator of the cellular hypoxic response. We previously showed that HIF-1 activation is essential for heat acclimation (AC) in Caenorhabditis elegans. Metabolic changes in AC rat hearts indicate HIF-1α activation in mammals as well. Here we characterize the HIF-1α profile and the transcriptional activation of its target genes following AC and following heat stress (HS) in hearts from nonacclimated (C; 24°C) and AC (34°C, 1 mo) rats. We used Western blot and immunohistochemistry to measure HIF-1α levels and EMSA and RT-PCR/quantitative RT-PCR to detect expression of the HIF-1α-targeted genes, including vascular endothelial growth factor ( Vegf), heme oxygenase-1 ( HO1), erythropoietin ( Epo), and Epo receptor ( EpoR). EpoR and Epo mRNA levels were measured to determine systemic effects in the kidneys and cross-tolerance effects in C and AC ischemic hearts (Langendorff, 75% ischemia, 40 min). The results demonstrated that 1) after AC, HIF-1α protein levels were increased, 2) HS alone induced transient HIF-1α upregulation, and 3) VEGF and HO1 mRNA levels increased after HS, with greater magnitude in the AC hearts. Epo mRNA in AC kidneys and EpoR mRNA in AC hearts were also elevated. In AC hearts, EpoR expression was markedly higher after HS or ischemia. Hearts from AC rats were dramatically protected against infarction after ischemia-perfusion. We conclude that HIF-1 contributes to the acclimation-ischemia cross-tolerance mechanism in the heart by induction of both chronic and inducible adaptive components.

Inhibition of mTOR Reverses the Ability of c-MYC To Block the Differentiation of Murine Granulocytes.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 310-310
Author(s):  
Meaghan Wall ◽  
Gretchen Poortinga ◽  
Richard B. Pearson ◽  
Ross D. Hannan ◽  
Grant A. McArthur
Keyword(s):  
Cell Cycle ◽  
Cell Growth ◽  
Target Genes ◽  
Terminal Differentiation ◽  
S Phase ◽  
Brdu Incorporation ◽  
Granulocytic Differentiation ◽  
Differentiation Potential ◽  
Protein Levels ◽  
Vehicle Treated Control

Abstract The proto-oncogene c-MYC encodes a bHLH leucine-zipper transcription factor that acts as a potent differentiation inhibitor and as a promoter of cell cycle progression. Additionally, c-MYC and mTOR are widely acknowledged as major regulators of cell growth, the process by which cells accumulate biomass. Both c-MYC overexpression and constitutive activation of the PI 3-kinase/mTOR pathway are frequent events in acute myeloid leukaemia; a haemopoietic malignancy characterised by failure to undergo terminal differentiation. In this study we used the MPRO system, an in vitro murine myeloid terminal differentiation model, to study the relationship between cell growth effectors and differentiation in more detail. Enforced expression of c-MYC by the addition of 4-hydoxytamoxifen (4-OHT) to MPRO cells carrying the inducible mycER fusion protein prevents downregulation of growth and impairs retinoid-induced terminal myeloid differentiation. Because downregulation of mTOR limits growth we hypothesised that inhibition of mTOR may reverse the phenotypic effects of c-MYC. Strikingly, pharmacological inhibition of mTOR by rapamycin, but not growth limitation by other means such as amino acid deprivation or cycloheximide treatment, restores differentiation in granulocytes with enforced c-MYC expression (74.0±2.0% mature granulocytes in the rapamycin+4-OHT-treated mycER MPROs vs 4.5±1.0% in the cells treated with 4-OHT alone and 92.9±1.1% in vehicle-treated controls). Rapamycin restores cell growth parameters to levels equivalent to those of vehicle-treated control cells undergoing physiological granulocytic differentiation (2–3 fold reduction in 35S methionine incorporation in rapamycin+4-OHT-treated and vehicle-treated controls compared to levels in 4-OHT-treated cells) and facilitates cell cycle exit (26.0±7.14% of rapamycin+4-OHT-treated cells and 10.7±2.48% of vehicle-treated control cells in S phase vs 51.9±1.72% of tamoxifen-treated cells in S phase as determined by BrdU incorporation). Interestingly, rapamycin attenuates c-MYC’s ability to activate transcription of its target genes without impairing activation of RARα target genes. c-mycER protein levels are reduced while levels of retrovirus-driven c-mycER mRNA do not fall in rapamycin-treated MPRO mycER cells. Furthermore, c-mycER protein levels decrease in rapamycin-treated MPRO cells expressing the ER fusion of the mycT58A point mutation known to increase protein stability. Overall, this data suggests that rapamycin restores the differentiation potential of granulocytes in the MPRO mycER system by regulating c-MYC at the level of protein translation, rather than at the level of gene transcription or protein degradation. These findings suggest that mTOR could be targeted to influence terminal differentiation regulated by MYC in haemopoietic malignancies.

Abstract 1115: Impaired Angiogenic Potential of Cardiac Progenitor Cells in Mice with a Cardiomyocyte-Restricted Knock Out of STAT3

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Philipp Fischer ◽  
Ewa Missol-Kolka ◽  
Nils-Holger Zschemisch ◽  
Christian Templin ◽  
Helmut Drexler ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Adipocyte Differentiation ◽  
Prostaglandin E ◽  
Mouse Heart ◽  
Cardiac Progenitor Cells ◽  
Rt Pcr ◽  
Differentiation Potential ◽  
Intramyocardial Injection ◽  
Knock Out

Mice with a cardiomyocyte-restricted knock out of STAT3 (KO: alpha-MHC-Cre tg/+; STAT3 flox/flox ) show a continuous decrease of the cardiac capillary density and develop heart failure beyond the age of 9 months. We sought to determine the paracrine influence of cardiomyocyte STAT3 on the endothelial differentiation potential of cardiac progenitor cells (CPC) of the adult mouse heart. Sca-1 + CPC were isolated from male mice hearts by MACS separation. STAT3 was entirely deleted in cardiomyocytes of KO mice, while CPC from KO showed normal expression of STAT3 (confirmed by PCR and Western blot). No difference in the total number of CPC per heart was observed between wildtype (WT: STAT3 flox/flox ) and KO mice. FACS analysis revealed a reduced number of endothelial progenitor cells (as defined by coexpression of Sca-1, CD31 and CD38, −25%, P<0.05) among CPC from KO compared to CPC from WT. The differentiation potential of CPC from WT and KO was analyzed during in vitro culture on fibronectin-coated plates. After 4 weeks of culture RT-PCR for CD31 and immunohistochemistry (IHC) for endothelial cell (EC) marker tie2 and isolectin B4 was performed. CPC from WT showed markedly more efficient EC differentiation and tube formation compared to CPC from KO (p<0.01). In contrast, adipocyte differentiation was enhanced in CPC from KO (p<0.05, oil red staining and RT-PCR). Proliferation capacity of CPC from KO was reduced by 33% (p<0.01) as compared to CPC from WT. Microarray results of freshly isolated CPC were consistent with the differences in EC and adipocyte differentiation (i.e. prostaglandin E receptor 3 up 2.3-fold in CPC from WT, Lipocalin-2 up 2.7-fold in CPC from KO). We did not observe cardiomyocyte differentiation (IHC for alpha-sarcomeric actinin; RT-PCR for Nkx 2.5, alpha-MHC, or alpha-skeletal actin) of CPC from both genotypes, neither in vitro by addition of oxytocin, 5-AZA, DMSO, nor following intramyocardial injection of CPC in vivo. Conclusion: STAT3-dependent paracrine mediators released from cardiomyocytes are determinants of differentiation and vasculogenic properties of new EC derived from cardiac progenitor cells. The identification of these factors may offer new approaches to enforce the endogenous vasculogenic repair potential of the adult heart.

Abstract 5569: Paracrine Effects of Cardiomyocyte STAT3 Determine the Vasculogenic Differentiation Potential of Cardiac Progenitor Cells: Potential Role of Endogenous Erythropoietin

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Philipp Fischer ◽  
Melanie Hoch ◽  
Britta Stapel ◽  
Helmut Drexler ◽  
Denise Hilfiker-Kleiner
Keyword(s):  
Progenitor Cells ◽  
Adipocyte Differentiation ◽  
Left Ventricular ◽  
Prostaglandin E ◽  
Cardiac Progenitor Cells ◽  
Rt Pcr ◽  
Paracrine Factors ◽  
Differentiation Potential ◽  
Paracrine Effects

Mice with a cardiomyocyte-restricted knock out of STAT3 (αMHC-Cretg/+; STAT3flox/flox, STAT3-KO) show a continuous decrease of cardiac vascularization and develop heart failure beyond the age of 9 months. We investigated the role of cardiomyocyte STAT3-driven paracrine effects on Sca-1+ cardiac progenitor cells (CPC) in the mouse heart. CPC were immunomag-netically isolated from KO and wildtype (STAT3flox/flox, WT) hearts (age: 3 months). PCR and Western blot confirmed deletion of STAT3 in cardiomyocytes of KO mice, while CPC from KO showed normal expression of STAT3. The total number of CPC per heart was similar between WT and KO mice. FACS analysis revealed a reduced number of endothelial progenitor cells (defined by co-expression of Sca-1, CD31 and CD38, −25%, P<0.05) in CPC from KO compared to CPC from WT. In vitro culture for 4 weeks on fibronectin-coated plates of CPC from KO revealed reduced proliferation (−33%, p<0.01), impaired endothelial cell (EC) tubeformation (monitored with Tie2, eNOS and CD31 immunohistochemistry (IHC), p<0.01) and enhanced adipocyte differentiation (oil red staining and RT-PCR, p<0.05) compared with CPC from WT. Microarray of freshly isolated CPC reflected this differences in EC and adipocyte differentiation on the mRNA level (i.e. EC marker Prostaglandin E Rezeptor-3: 2.3-fold lower; adipocyte marker Lipocalin-2 2.7-fold higher in CPC from KO hearts). Microarray results from whole left ventricular tissue showed a decrease in gene expression of Erythropoietin (Epo) in KO hearts (-9,25-fold). ELISA, IHC and methylcellulose assay confirm expression of active EPO by cardiomyocytes. CPC express high levels of EPO receptor (IHC, RT-PCR). Epo enhanced tube formation and sprouting of EC and attenuated adipocyte differentiation of CPCs from KO. In vivo treatment with Epo rescued impaired proliferation, promoted EC differentiation and attenuated adipocyte differentiation of CPC from KO hearts. Conclusion: STAT3-dependent paracrine factors from cardiomyocytes regulate proliferation, differentiation and vasculogenic properties of CPCs. Cardiomyocyte derived EPO is an important paracrine mediator that promotes differentiation into EC and attenuates differentiation into adipocytes from CPCs in the adult heart.

scholarly journals A high-fat diet induces lower expression of retinoid receptors and their target genes GAP-43/neuromodulin and RC3/neurogranin in the rat brain

2010 ◽  
Vol 103 (12) ◽  
pp. 1720-1729 ◽  
Author(s):  
Benjamin Buaud ◽  
Laure Esterle ◽  
Carole Vaysse ◽  
Serge Alfos ◽  
Nicole Combe ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Retinoic Acid ◽  
Fatty Acid ◽  
Dietary Fat ◽  
High Fat Diet ◽  
Target Genes ◽  
Rt Pcr ◽  
High Fat ◽  
Pufa Content ◽  
Protein Levels

Numerous studies have reported an association between cognitive impairment in old age and nutritional factors, including dietary fat. Retinoic acid (RA) plays a central role in the maintenance of cognitive processes via its nuclear receptors (NR), retinoic acid receptor (RAR) and retinoid X receptor (RXR), and the control of target genes, e.g. the synaptic plasticity markers GAP-43/neuromodulin and RC3/neurogranin. Given the relationship between RA and the fatty acid signalling pathways mediated by their respective NR (RAR/RXR and PPAR), we investigated the effect of a high-fat diet (HFD) on (1) PUFA status in the plasma and brain, and (2) the expression of RA and fatty acid NR (RARβ, RXRβγ and PPARδ), and synaptic plasticity genes (GAP-43 and RC3), in young male Wistar rats. In the striatum of rats given a HFD for 8 weeks, real-time PCR (RT-PCR) revealed a decrease in mRNA levels of RARβ ( − 14 %) and PPARδ ( − 13 %) along with an increase in RXRβγ (+52 %). Concomitantly, RT-PCR and Western blot analysis revealed (1) a clear reduction in striatal mRNA and protein levels of RC3 ( − 24 and − 26 %, respectively) and GAP-43 ( − 10 and − 42 %, respectively), which was confirmed by in situ hybridisation, and (2) decreased hippocampal RC3 and GAP-43 protein levels (approximately 25 %). Additionally, HFD rats exhibited a significant decrease in plasma ( − 59 %) and brain ( − 6 %) n-3 PUFA content, mainly due to the loss of DHA. These results suggest that dietary fat induces neurobiological alterations by modulating the brain RA signalling pathway and n-3 PUFA content, which have been previously correlated with cognitive impairment.

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