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21 result(s) for "Celik, Selvi"
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Profiling of the plasma proteome across different stages of human heart failure
Heart failure (HF) is a major public health problem characterized by inability of the heart to maintain sufficient output of blood. The systematic characterization of circulating proteins across different stages of HF may provide pathophysiological insights and identify therapeutic targets. Here we report application of aptamer-based proteomics to identify proteins associated with prospective HF incidence in a population-based cohort, implicating modulation of immunological, complement, coagulation, natriuretic and matrix remodeling pathways up to two decades prior to overt disease onset. We observe further divergence of these proteins from the general population in advanced HF, and regression after heart transplantation. By leveraging coronary sinus samples and transcriptomic tools, we describe likely cardiac and specific cellular origins for several of the proteins, including Nt-proBNP, thrombospondin-2, interleukin-18 receptor, gelsolin, and activated C5. Our findings provide a broad perspective on both cardiac and systemic factors associated with HF development. Heart failure is a major health issue worldwide. Here, Egerstedt et al. perform proteomic profiling of human plasma at different stages of heart failure, providing a comprehensive analysis of changes in the plasma proteome during disease progression.
Inhibition of the long non-coding RNA NEAT1 protects cardiomyocytes from hypoxia in vitro via decreased pri-miRNA processing
While restoration of coronary blood flow to the ischemic heart is the most effective strategy for reducing infarct size, reperfusion injury represents a significant limiting factor on clinical outcomes in myocardial infarction patients. Ischemic preconditioning (IPC) has been shown to inhibit reperfusion injury and represents an attractive model for studying cardioprotective signal transduction pathways. Long non-coding RNAs (lncRNAs) are a structurally and functionally heterogenous class of RNA transcripts with unknown roles in IPC-induced cardioprotection. Through microarray-based expression profiling of 31,423 lncRNAs in cardiac tissue from IPC mice, we identified the nuclear transcript Neat1 to be rapidly and robustly decreased in response to IPC. siRNA-mediated knock down of Neat1 reduced apoptosis and necrosis in murine cardiomyocytes (CM) and human iPS-derived CMs in response to prolonged hypoxia and hypoxia-reoxygenation, assessed with Annexin V/propidium iodide-staining, a Caspase 3/7 activity assay, LDH release, and western blot for cleaved Caspase 3. Mechanistically, Neat1 was shown to regulate processing of pro-apoptotic microRNA-22 (miR-22) in murine and human CM nuclei using a luciferase reporter assay. Hypoxia-induced downregulation of Neat1 was shown to result in accumulation of unprocessed pri-miRNA and decreased availability of biologically active miRNA, including miR-22. Addition of exogenous synthetic miR-22 reversed the protective effect of Neat1 knock down in human iPS-CM. In conclusion, we have identified the nuclear lncRNA Neat1 as part of a conserved oxygen-sensitive feedback mechanism by regulation of miRNA processing and a potential target in cardioprotection.
Whole genome sequencing in early onset advanced heart failure
The genetic contributions to early onset heart failure (HF) are incompletely understood. Genetic testing in advanced HF patients undergoing heart transplantation (HTx) may yield clinical benefits, but data is limited. We performed deep-coverage whole genome sequencing (WGS) in 102 Swedish HTx recipients. Gene lists were compiled through a systematic literature review. Variants were prioritized for pathogenicity and classified manually. We also compared polygenic HF risk scores to a population-based cohort. We found a pathogenic (LP/P) variant in 34 individuals (34%). Testing yield was highest in hypertrophic (63% LP/P carriers), dilated (40%) and arrhythmogenic right ventricular (33%) cardiomyopathy and lower in ischemic cardiomyopathy (10%). A family history was more common in LP/P variant carriers than in non-carriers but was present in less than half of carriers (44% vs 13%, P  < 0.001), whereas age was similar. Polygenic risk scores were similar in HTx recipients and the population cohort. In conclusion, we observed a high prevalence of pathogenic cardiomyopathy gene variants in individuals with early-onset advanced HF, which could not accurately be ruled out by family history and age. In contrast, we did not observe higher polygenic risk scores in early onset advanced HF cases than in the general population.
Vascular smooth muscle-specific YAP/TAZ deletion triggers aneurysm development in mouse aorta
Inadequate adaption to mechanical forces, including blood pressure, contributes to development of arterial aneurysms. Recent studies have pointed to a mechano-protective role of YAP and TAZ in vascular smooth muscle cells (SMCs). Here, we identified reduced expression of YAP1 in human aortic aneurysms. Vascular SMC-specific knockouts (KOs) of YAP/TAZ were thus generated using the novel integrin α8 (Itga8)-Cre mouse model (i8-YT-KO). i8-YT-KO mice spontaneously developed aneurysms in the abdominal aorta within two weeks of knockout induction and in smaller arteries at later times. The vascular specificity of the Itga8-Cre circumvented gastrointestinal effects. Aortic aneurysms were characterized by elastin disarray, SMC apoptosis, and accumulation of proteoglycans and immune cell populations. RNA-sequencing, proteomics, and myography demonstrated decreased contractile differentiation of SMCs and impaired vascular contractility. This associated with partial loss of myocardin expression, reduced blood pressure, and edema. Mediators in the inflammatory cGAS-STING pathway, were increased. A sizeable increase of SOX9, along with several direct target genes, including aggrecan (Acan), contributed to proteoglycan accumulation. This was the earliest detectable change, occurring three days after knockout induction and before the pro-inflammatory transition. In conclusion, Itga8-Cre deletion of YAP and TAZ represents a rapid and spontaneous aneurysm model that recapitulates features of human abdominal aortic aneurysms.
Sprouty3 and Sprouty4, Two Members of a Family Known to Inhibit FGF-Mediated Signaling, Exert Opposing Roles on Proliferation and Migration of Glioblastoma-Derived Cells
Dysregulation of receptor tyrosine kinase-induced pathways is a critical step driving the oncogenic potential of brain cancer. In this study, we investigated the role of two members of the Sprouty (Spry) family in brain cancer-derived cell lines. Using immunoblot analyses we found essential differences in the pattern of endogenous Spry3 and Spry4 expression. While Spry4 expression was mitogen-dependent and repressed in a number of cells from higher malignant brain cancers, Spry3 levels neither fluctuated in response to serum withdrawal nor were repressed in glioblastoma (GBM)-derived cell lines. In accordance to the well-known inhibitory role of Spry proteins in fibroblast growth factor (FGF)-mediated signaling, both Spry proteins were able to interfere with FGF-induced activation of the MAPK pathway although to a different extent. In response to serum solely, Spry4 exerts its role as a negative regulator of MAPK activation. Ectopic expression of Spry4 inhibited proliferation and migration of GBM-originated cells, positioning it as a tumor suppressor in brain cancer. In contrast, elevated Spry3 levels accelerated both proliferation and migration of these cell lines, while repression of Spry3 levels using shRNA caused a significant diminished growth and migration velocity rate of a GBM-derived cell line. This argues for a tumor-promoting function of Spry3 in GBMs. Based on these data we conclude that Spry3 and Spry4 fulfill different if not opposing roles within the cancerogenesis of brain malignancies.
Treatment with a GnRH receptor agonist, but not the GnRH receptor antagonist degarelix, induces atherosclerotic plaque instability in ApoE−/− mice
Androgen-deprivation therapy (ADT) for prostate cancer has been associated with increased risk for development of cardiovascular events and recent pooled analyses of randomized intervention trials suggest that this primarily is the case for patients with pre-existing cardiovascular disease treated with gonadotropin-releasing hormone receptor (GnRH-R) agonists. In the present study we investigated the effects of the GnRH-R agonist leuprolide and the GnRH-R antagonist degarelix on established atherosclerotic plaques in ApoE −/− mice. A shear stress modifier was used to produce both advanced and more stable plaques in the carotid artery. After 4 weeks of ADT, increased areas of necrosis was observed in stable plaques from leuprolide-treated mice (median and IQR plaque necrotic area in control, degarelix and leuprolide-treated mice were 0.6% (IQR 0–3.1), 0.2% (IQR 0–4.4) and 11.0% (IQR 1.0-19.8), respectively). There was also evidence of increased inflammation as assessed by macrophage immunohistochemistry in the plaques from leuprolide-treated mice, but we found no evidence of such changes in plaques from control mice or mice treated with degarelix. Necrosis destabilizes plaques and increases the risk for rupture and development of acute cardiovascular events. Destabilization of pre-existing atherosclerotic plaques could explain the increased cardiovascular risk in prostate cancer patients treated with GnRH-R agonists.
Cardiomyocyte antisense transcription regulates exon usage in the elastic spring region of Titin to modulate sarcomere function
The spring-like sarcomere protein Titin (TTN) is a key determinant of cardiac passive stiffness and diastolic function. Alternative splicing of TTN I-band exons produce protein isoforms with variable size and elasticity, but the mechanisms regulating TTN exon skipping and isoform composition in the human heart are not well studied. Non-coding RNA transcripts from the antisense strand of protein-coding genes have been shown to regulate alternative splicing of the sense gene. The TTN gene locus harbours >80 antisense transcripts with unknown function in the human heart. The aim of this study was to determine if TTN antisense transcripts play a role in alternative splicing of TTN. RNA-sequencing and RNA in situ hybridization (ISH) of cardiac tissue from unused organ donor hearts (n=7) and human induced pluripotent stem cell-derived cardiomyocytes (iPS-CMs) were used to determine the expression and localization of TTN antisense transcripts. The effect of siRNA-mediated knock down of TTN antisense transcripts on TTN exon usage in iPS-CMs was determined using RNA-sequencing. Live cell imaging with sarcomere tracking was used to analyze the effect of antisense transcript knock down on sarcomere length, organization and contraction dynamics. RNA ISH, immunofluorescence and high content microscopy was performed in iPS-CMs to study the interaction between antisense transcripts, TTN mRNA and splice factor protein RBM20. In mapping TTN antisense transcription, we found that TTN-AS1-276 was the predominant transcript in the human heart and that it was mainly localized in cardiomyocyte nuclear chromatin. Knock down of TTN-AS1-276 in human iPS-CMs resulted in decreased interaction between the splicing factor RBM20 and TTN pre-mRNA, decreased TTN I-band exon skipping, and markedly lower expression of the less elastic TTN isoform N2B. The effect on TTN exon usage was independent of sense-antisense exon overlap and polymerase II elongation rate. Furthermore, knockdown resulted in longer sarcomeres with preserved alignment, improved fractional shortening and relaxation times. We demonstrate a role for the cardiac TTN antisense transcript TTN-AS1-276 in facilitating alternative splicing of TTN and regulating sarcomere properties. This transcript could constitute a target for improving cardiac passive stiffness and diastolic function in conditions such as heart failure with preserved ejection fraction.
Türkiye'Nin Enerjide Dışa Bağımlılığının Azaltılmasında Yenilenebilir Enerji Kaynaklarının Önemi
Günümüzde mal ve hizmet üretimindeki genişlemeye paralel olarak enerjiye olan talep giderek artmaktadır. Mevcut enerji talebinin önemli bir kısmını karşılayan fosil yakıtlar (petrol, kömür, doğalgaz) ise sonsuz ihtiyaçları karşılayabilme konusundasınırlı enerji kaynaklarıdır. Fosil yakıtların mevcudiyeti noktasında sıkıntı yaşayan ülkeler bu kaynağa ulaşılabilirlik konusunda yüksek maliyetlere katlanmak zorunda kalmaktadır. Bu durumda ülkelerin ekonomik büyümeleri açısından fosil yakıtlarınyerini alacak yenilenebilir enerji kaynaklarının gerekli olduğu ortaya çıkmaktadır. Türkiye artan enerji talebini karşılayabilecek yeterli miktarda fosil yakıt kaynaklarına sahip olmadığından dolayı yüksek maliyetlere katlanarak enerjide dışa bağımlı hale gelmiştir. Türkiye geniş bir kaynak potansiyeline sahip olduğu yenilenebilir enerji kaynaklarının kullanımına yönelik AR-GE çalışmaları ve sürdürülebilir enerji politikaları ile enerjide dışa bağımlılığını azaltabilir. Bu çalışmanın amacı, fosil yakıtlar yerine kullanılabilecek çevre dostu, sınırsız ömre sahip ve düşük maliyetli yenilenebilir enerji kaynaklarının Türkiye açısından önemini ortaya koymaktır. Birinci bölümde enerji kaynaklarının tanımlarına, özelliklerine, avantaj ve dezavantajlarına yer verilmiştir. İkinci bölümde yenilenebilir enerji kaynaklarının Dünya ve Türkiye açısından potansiyeli, kurulu gücü ve yatırım maliyetleri incelenmiştir. Son bölümde ise fosil yakıtlar ile yenilenebilir enerji kaynaklarının üretimi, tüketimi, ithalattaki payları ve yatırım maliyetleri karşılaştırılarak analiz edilmiştir.
Radiosurgery effects and adverse effects in symptomatic eloquent brain-located Cavernomas
In this study, the dose schedule efficacy, safety and late adverse effects of stereotactic radiosurgery (SRS) were evaluated for patients with symptomatic cavernomas who were not eligible for surgery and treated with SRS. Between January 2013 and December 2018, 53 patients with cavernomas were treated using SRS with the CyberKnife® system. Patients’ diseases were deeply located or were in subcortical functional brain regions. In addition to bleeding, 23 (43.4%) patients had epilepsy, 12 (22.6%) had neurologic symptoms and 16 patients (30.2%) had severe headaches. The median volume was 741 (range, 421–1351) mm3, and the median dose was 15 (range, 14–16) Gy in one fraction. After treatment, six (50%) of 12 patients with neurologic deficits still had deficits. Rebleeding after treatment developed in only two (3.8%) patients. The drug was completely stopped in 14 (60.9%) out of 23 patients who received epilepsy treatment, and the dose of levetiracetam decreased from 2000 mg to 1000 mg in four (17.3%) of nine patients. Radiologically, complete response (CR) was observed in 13 (24.5%) patients, and partial responses (PR) were observed in 32 (60.2%) patients. Clinical response of CR was observed in 30 (56.6%) patients, PR was observed in 16 (30.2%), stable disease (SD) was observed in three (5.7%) and four (7.5%) patients progressed. In conclusion, SRS applied in the appropriate dose schedule may be an effective and reliable method in terms of symptom control and prevention of rebleeding, especially in patients with inoperable cavernomas.
An observational, multicenter, registry-based cohort study of Turkish Neonatal Society in neonates with Hypoxic ischemic encephalopathy
Hypoxic ischemic encephalopathy (HIE) is a significant cause of mortality and short- and long-term morbidities. Therapeutic hypothermia (TH) has been shown to be the standard care for HIE of infants ≥36 weeks gestational age (GA), as it has been demonstrated to reduce the rates of mortality, and adverse neurodevelopmental outcomes. This study aims to determine the incidence of HIE in our country, to assess the TH management in infants with HIE, and present short-term outcomes of these infants. The Turkish Hypoxic Ischemic Encephalopathy Online Registry database was established for this multicenter, prospective, observational, nationally-based cohort study to evaluate the data of infants born at ≥34 weeks GA who displayed evidence of neonatal encephalopathy (NE) between March, 2020 and April 2022. The incidence of HIE among infants born at ≥36 weeks GA (n = 965) was 2.13 per 1000 live births (517:242440), and accounting for 1.55% (965:62062) of all neonatal intensive care unit admissions. The rates of mild, moderate and severe HİE were 25.5% (n = 246), 58.9% (n = 568), and 15.6% (n = 151), respectively. Infants with severe HIE had higher rates of abnormal magnetic resonance imaging (MRI) findings, and mortality (p<0.001). No significant difference in mortality and abnormal MRI results was found according to the time of TH initiation (<3 h, 3-6 h and >6 h) (p>0.05). TH was administered to 85 (34.5%) infants with mild HIE, and of those born of 34-35 weeks of GA, 67.4% (n = 31) received TH. A total of 58 (6%) deaths were reported with a higher mortality rate in infants born at 34-35 weeks of GA (OR 3.941, 95% Cl 1.446-10.7422, p = 0.007). The incidence of HIE remained similar over time with a reduction in mortality rate. The timing of TH initiation, whether <3 or 3-6 h, did not result in lower occurrences of brain lesions on MRI or mortality. An increasing number of infants with mild HIE and late preterm infants with HIE are receiving TH; however, the indications for TH require further clarification. Longer follow-up studies are necessary for this vulnerable population.