Publications by authors named "Elisabeth M Zeisberg"

39 Publications

Real-time cardiovascular magnetic resonance T1 and extracellular volume fraction mapping for tissue characterisation in aortic stenosis.

J Cardiovasc Magn Reson 2020 06 22;22(1):46. Epub 2020 Jun 22.

University Medical Center Göttingen, Department of Cardiology and Pneumology, Georg-August University, Robert-Koch-Str. 40, 37099, Göttingen, Germany.

Background: Myocardial fibrosis is a major determinant of outcome in aortic stenosis (AS). Novel fast real-time (RT) cardiovascular magnetic resonance (CMR) mapping techniques allow comprehensive quantification of fibrosis but have not yet been compared against standard techniques and histology.

Methods: Patients with severe AS underwent CMR before (n = 110) and left ventricular (LV) endomyocardial biopsy (n = 46) at transcatheter aortic valve replacement (TAVR). Midventricular short axis (SAX) native, post-contrast T1 and extracellular volume fraction (ECV) maps were generated using commercially available modified Look-Locker Inversion recovery (MOLLI) (native: 5(3)3, post-contrast: 4(1)3(1)2) and RT single-shot inversion recovery Fast Low-Angle Shot (FLASH) with radial undersampling. Focal late gadolinium enhancement was excluded from T1 and ECV regions of interest. ECV and LV mass were used to calculate LV matrix volumes. Variability and agreements were assessed between RT, MOLLI and histology using intraclass correlation coefficients, coefficients of variation and Bland Altman analyses.

Results: RT and MOLLI derived ECV were similar for midventricular SAX slice coverage (26.2 vs. 26.5, p = 0.073) and septal region of interest (26.2 vs. 26.5, p = 0.216). MOLLI native T1 time was in median 20 ms longer compared to RT (p < 0.001). Agreement between RT and MOLLI was best for ECV (ICC > 0.91), excellent for post-contrast T1 times (ICC > 0.81) and good for native T1 times (ICC > 0.62). Diffuse collagen volume fraction by biopsies was in median 7.8%. ECV (RT r = 0.345, p = 0.039; MOLLI r = 0.40, p = 0.010) and LV matrix volumes (RT r = 0.45, p = 0.005; MOLLI r = 0.43, p = 0.007) were the only parameters associated with histology.

Conclusions: RT mapping offers fast and sufficient ECV and LV matrix volume calculation in AS patients. ECV and LV matrix volume represent robust and universally comparable parameters with associations to histologically assessed fibrosis and may emerge as potential targets for clinical decision making.
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http://dx.doi.org/10.1186/s12968-020-00632-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7310147PMC
June 2020

Endothelial-to-mesenchymal transition compromises vascular integrity to induce Myc-mediated metabolic reprogramming in kidney fibrosis.

Sci Signal 2020 06 9;13(635). Epub 2020 Jun 9.

Department of Cancer Biology, Metastasis Research Center, University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA.

Endothelial-to-mesenchymal transition (EndMT) is a cellular transdifferentiation program in which endothelial cells partially lose their endothelial identity and acquire mesenchymal-like features. Renal capillary endothelial cells can undergo EndMT in association with persistent damage of the renal parenchyma. The functional consequence(s) of EndMT in kidney fibrosis remains unexplored. Here, we studied the effect of Twist or Snail deficiency in endothelial cells on EndMT in kidney fibrosis. Conditional deletion of (which encodes Twist) or (which encodes Snail) in VE-cadherin or Tie1 endothelial cells inhibited the emergence of EndMT and improved kidney fibrosis in two different kidney injury/fibrosis mouse models. Suppression of EndMT limited peritubular vascular leakage, reduced tissue hypoxia, and preserved tubular epithelial health and function. Hypoxia, which was exacerbated by EndMT, resulted in increased Myc abundance in tubular epithelial cells, enhanced glycolysis, and suppression of fatty acid oxidation. Pharmacological suppression or epithelial-specific genetic ablation of Myc in tubular epithelial cells ameliorated fibrosis and restored renal parenchymal function and metabolic homeostasis. Together, these findings demonstrate a functional role for EndMT in the response to kidney capillary endothelial injury and highlight the contribution of endothelial-epithelial cross-talk in the development of kidney fibrosis with a potential for therapeutic intervention.
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http://dx.doi.org/10.1126/scisignal.aaz2597DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7790440PMC
June 2020

CRISPR/Cas Derivatives as Novel Gene Modulating Tools: Possibilities and In Vivo Applications.

Int J Mol Sci 2020 Apr 25;21(9). Epub 2020 Apr 25.

Department of Cardiology and Pneumology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany.

The field of genome editing started with the discovery of meganucleases (e.g., the LAGLIDADG family of homing endonucleases) in yeast. After the discovery of transcription activator-like effector nucleases and zinc finger nucleases, the recently discovered clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated proteins (Cas) system has opened a new window of applications in the field of gene editing. Here, we review different Cas proteins and their corresponding features including advantages and disadvantages, and we provide an overview of the different endonuclease-deficient Cas protein (dCas) derivatives. These dCas derivatives consist of an endonuclease-deficient Cas9 which can be fused to different effector domains to perform distinct in vitro applications such as tracking, transcriptional activation and repression, as well as base editing. Finally, we review the in vivo applications of these dCas derivatives and discuss their potential to perform gene activation and repression in vivo, as well as their potential future use in human therapy.
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http://dx.doi.org/10.3390/ijms21093038DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7246536PMC
April 2020

Serelaxin alleviates cardiac fibrosis through inhibiting endothelial-to-mesenchymal transition via RXFP1.

Theranostics 2020 4;10(9):3905-3924. Epub 2020 Mar 4.

Department of Cardiology and Pneumology, University Medical Center of Göttingen, Georg-August University, Göttingen, Germany.

: Cardiac fibrosis is an integral constituent of every form of chronic heart disease, and persistence of fibrosis reduces tissue compliance and accelerates the progression to heart failure. Relaxin-2 is a human hormone, which has various physiological functions such as mediating renal vasodilation in pregnancy. Its recombinant form Serelaxin has recently been tested in clinical trials as a therapy for acute heart failure but did not meet its primary endpoints. The aim of this study is to examine whether Serelaxin has an anti-fibrotic effect in the heart and therefore could be beneficial in chronic heart failure. : We utilized two different cardiac fibrosis mouse models (ascending aortic constriction (AAC) and Angiotensin II (ATII) administration via osmotic minipumps) to assess the anti-fibrotic potential of Serelaxin. Histological analysis, immunofluorescence staining and molecular analysis were performed to assess the fibrosis level and indicate endothelial cells which are undergoing EndMT. TGFβ1-induced endothelial-to-mesenchymal transition (EndMT) assays were performed in human coronary artery endothelial cells and mouse cardiac endothelial cells (MCECs) and were examined using molecular methods. Chromatin immunoprecipitation-qPCR assay was utilized to identify the Serelaxin effect on chromatin remodeling in the promoter region in MCECs. : Our results demonstrate a significant and dose-dependent anti-fibrotic effect of Serelaxin in the heart in both models. We further show that Serelaxin mediates this effect, at least in part, through inhibition of EndMT through the endothelial Relaxin family peptide receptor 1 (RXFP1). We further demonstrate that Serelaxin administration is able to increase its own receptor expression (RXFP1) through epigenetic regulation in form of histone modifications by attenuating TGFβ-pSMAD2/3 signaling in endothelial cells. : This study is the first to identify that Serelaxin increases the expression of its own receptor RXFP1 and that this mediates the inhibition of EndMT and cardiac fibrosis, suggesting that Serelaxin may have a beneficial effect as anti-fibrotic therapy in chronic heart failure.
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http://dx.doi.org/10.7150/thno.38640DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7086357PMC
March 2020

The axis of local cardiac endogenous Klotho-TGF-β1-Wnt signaling mediates cardiac fibrosis in human.

J Mol Cell Cardiol 2019 11 11;136:113-124. Epub 2019 Sep 11.

Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA. Electronic address:

Background: Cardiovascular fibrosis is a major contributor to cardiovascular disease, the primary cause of death in patients with chronic kidney disease (CKD). We previously reported expression of endogenous Klotho in human arteries, and that CKD is a state of Klotho deficiency, resulting in vascular calcification, but myocardial expression of Klotho is poorly understood. This study aimed to further clarify endogenous Klotho's functional roles in cardiac fibrosis in patients with underlying CKD.

Methods And Results: Human atrial appendage specimens were collected during cardiac surgery from individuals with or without CKD. Cardiac fibrosis was quantified using trichrome staining. For endogenous Klotho functional studies, primary human cardiomyocytes (HCMs) were treated with uremic serum from CKD patients or recombinant human TGF-β1. The effects of endogenous Klotho in HCMs were studied using Klotho-siRNA and Klotho-plasmid transfection. Both gene and protein expression of endogenous Klotho are found in human heart, but decreased Klotho expression is clearly associated with the degree of cardiac fibrosis in CKD patients. Moreover, we show that endogenous Klotho is expressed by HCMs and cardiac fibroblasts (HCFs) but that HCM expression is suppressed by uremic serum or TGF-β1. Klotho knockdown or overexpression aggravates or mitigates TGF-β1-induced fibrosis and canonical Wnt signaling in HCMs, respectively. Furthermore, co-culture of HCMs with HCFs increases TGF-β1-induced fibrogenic proteins in HCFs, but overexpression of endogenous Klotho in HCMs mitigates this effect, suggesting functional crosstalk between HCMs and HCFs.

Conclusions: Our data from analysis of human hearts as well as functional in vitro studies strongly suggests that the loss of cardiac endogenous Klotho in CKD patients, specifically in cardiomyocytes, facilitates intensified TGF-β1 signaling which enables more vigorous cardiac fibrosis through upregulated Wnt signaling. Upregulation of endogenous Klotho inhibits pathogenic Wnt/β-catenin signaling and may offer a novel strategy for prevention and treatment of cardiac fibrosis in CKD patients.
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http://dx.doi.org/10.1016/j.yjmcc.2019.09.004DOI Listing
November 2019

Causal Connections From Chronic Kidney Disease to Cardiac Fibrosis.

Semin Nephrol 2018 11;38(6):629-636

Department of Cardiology and Pneumology, University Medical Center Göttingen, Göttingen, Germany; German Center for Cardiovascular Research (DZHK), Partner Site, Goettingen, Germany. Electronic address:

Cardiovascular disease and heart failure are the primary cause of morbidity and mortality in patients with chronic kidney disease. Because impairment of kidney function correlates with heart failure and cardiac fibrosis, a kidney-heart axis is suspected. Although our understanding of the underlying mechanisms still is evolving, the possibility that kidney-heart messengers could be intercepted offers ample reason to focus on this clinically highly relevant problem. Here, we review the current knowledge of how kidney injury causes heart failure and fibrosis.
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http://dx.doi.org/10.1016/j.semnephrol.2018.08.007DOI Listing
November 2018

Epigenetic Regulation of Endothelial-to-Mesenchymal Transition in Chronic Heart Disease.

Arterioscler Thromb Vasc Biol 2018 09;38(9):1986-1996

From the Department of Cardiology and Pneumology, University Medical Center of Göttingen, Georg-August University, Germany (M.S.H., X.X., E.M.Z.).

Endothelial-to-mesenchymal transition (EndMT) is a process in which endothelial cells lose their properties and transform into fibroblast-like cells. This transition process contributes to cardiac fibrosis, a common feature of patients with chronic heart failure. To date, no specific therapies to halt or reverse cardiac fibrosis are available, so knowledge of the underlying mechanisms of cardiac fibrosis is urgently needed. In addition, EndMT contributes to other cardiovascular pathologies such as atherosclerosis and pulmonary hypertension, but also to cancer and organ fibrosis. Remarkably, the molecular mechanisms driving EndMT are largely unknown. Epigenetics play an important role in regulating gene transcription and translation and have been implicated in the EndMT process. Therefore, epigenetics might be the missing link in unraveling the underlying mechanisms of EndMT. Here, we review the involvement of epigenetic regulators during EndMT in the context of cardiac fibrosis. The role of DNA methylation, histone modifications (acetylation and methylation), and noncoding RNAs (microRNAs, long noncoding RNAs, and circular RNAs) in the facilitation and inhibition of EndMT are discussed, and potential therapeutic epigenetic targets will be highlighted.
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http://dx.doi.org/10.1161/ATVBAHA.118.311276DOI Listing
September 2018

Endothelial-to-mesenchymal transition shapes the atherosclerotic plaque and modulates macrophage function.

FASEB J 2019 02 27;33(2):2278-2289. Epub 2018 Sep 27.

Division of Nephrology and Hypertension, Department of Internal Medicine, Hannover Medical School, Hannover, Germany.

Endothelial cells can acquire a mesenchymal phenotype upon irritation [endothelial-to-mesenchymal transition (EndMT)]. Macrophages accumulate in the atherosclerotic plaque. This study addressed whether macrophages modulate EndMT and delineated a reciprocal effect of EndMT on macrophage functions in atherosclerosis. In atherosclerotic murine and human aortas, endothelial cells with mesenchymal markers were elevated by confocal microscopy and flow cytometric analysis. Increased EndMT master transcription factor Snai1 expression and extracellular matrix are consistent with enhanced EndMT in this condition. Hypoxia was detected in individual aortic EndMT cells in vivo and rapidly induced a similar EndMT phenotype in vitro. As a novel inducer of EndMT, macrophages, which are abundant in the atherosclerotic lesions, enhance mesothelial marker expression during coculture in vitro. In the reverse relationship, EndMT altered endothelial colony-stimulating factor expression. Functionally, EndMT cell-conditioned media attenuated macrophage proliferation, antigen-presenting cell marker expression, and TNF-α production in response to oxidized LDL but increased oxidized LDL uptake and scavenger receptor expression. These experiments demonstrate that macrophages promote partial EndMT. In turn, EndMT cells modulate macrophage phenotype and lipid uptake. Our data suggest that EndMT shapes macrophage and endothelial cell phenotypes, thus affecting internal atherosclerotic plaque in addition to surface structure.-Helmke, A., Casper, J., Nordlohne, J., David, S., Haller, H., Zeisberg, E. M., von Vietinghoff, S. Endothelial-to-mesenchymal transition shapes the atherosclerotic plaque and modulates macrophage function.
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http://dx.doi.org/10.1096/fj.201801238RDOI Listing
February 2019

Sarcoplasmic reticulum calcium leak contributes to arrhythmia but not to heart failure progression.

Sci Transl Med 2018 09;10(458)

Department of Cardiology and Pneumology, Georg-August-University, 37075 Göttingen, Germany.

Increased sarcoplasmic reticulum (SR) Ca leak via the cardiac ryanodine receptor (RyR2) has been suggested to play a mechanistic role in the development of heart failure (HF) and cardiac arrhythmia. Mice treated with a selective RyR2 stabilizer, rycal S36, showed normalization of SR Ca leak and improved survival in pressure overload (PO) and myocardial infarction (MI) models. The development of HF, measured by echocardiography and molecular markers, showed no difference in rycal S36- versus placebo-treated mice. Reduction of SR Ca leak in the PO model by the rycal-unrelated RyR2 stabilizer dantrolene did not mitigate HF progression. Development of HF was not aggravated by increased SR Ca leak due to RyR2 mutation (R2474S) in volume overload, an SR Ca leak-independent HF model. Arrhythmia episodes were reduced by rycal S36 treatment in PO and MI mice in vivo and ex vivo in Langendorff-perfused hearts. Isolated cardiomyocytes from murine failing hearts and human ventricular failing and atrial nonfailing myocardium showed reductions in delayed afterdepolarizations, in spontaneous and induced Ca waves, and in triggered activity in rycal S36 versus placebo cells, whereas the Ca transient, SR Ca load, SR Ca adenosine triphosphatase function, and action potential duration were not affected. Rycal S36 treatment of human induced pluripotent stem cells isolated from a patient with catecholaminergic polymorphic ventricular tachycardia could rescue the leaky RyR2 receptor. These results suggest that SR Ca leak does not primarily influence contractile HF progression, whereas rycal S36 treatment markedly reduces ventricular arrhythmias, thereby improving survival in mice.
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http://dx.doi.org/10.1126/scitranslmed.aan0724DOI Listing
September 2018

High-fidelity CRISPR/Cas9- based gene-specific hydroxymethylation rescues gene expression and attenuates renal fibrosis.

Nat Commun 2018 08 29;9(1):3509. Epub 2018 Aug 29.

German Center for Cardiovascular Research (DZHK) Partner Site, Göttingen, Germany.

While suppression of specific genes through aberrant promoter methylation contributes to different diseases including organ fibrosis, gene-specific reactivation technology is not yet available for therapy. TET enzymes catalyze hydroxymethylation of methylated DNA, reactivating gene expression. We here report generation of a high-fidelity CRISPR/Cas9-based gene-specific dioxygenase by fusing an endonuclease deactivated high-fidelity Cas9 (dHFCas9) to TET3 catalytic domain (TET3CD), targeted to specific genes by guiding RNAs (sgRNA). We demonstrate use of this technology in four different anti-fibrotic genes in different cell types in vitro, among them RASAL1 and Klotho, both hypermethylated in kidney fibrosis. Furthermore, in vivo lentiviral delivery of the Rasal1-targeted fusion protein to interstitial cells and of the Klotho-targeted fusion protein to tubular epithelial cells each results in specific gene reactivation and attenuation of fibrosis, providing gene-specific demethylating technology in a disease model.
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http://dx.doi.org/10.1038/s41467-018-05766-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6115451PMC
August 2018

Pharmacological induction of hypoxia-inducible transcription factor ARNT attenuates chronic kidney failure.

J Clin Invest 2018 07 11;128(7):3053-3070. Epub 2018 Jun 11.

Department of Nephrology and Rheumatology.

Progression of chronic kidney disease associated with progressive fibrosis and impaired tubular epithelial regeneration is still an unmet biomedical challenge because, once chronic lesions have manifested, no effective therapies are available as of yet for clinical use. Prompted by various studies across multiple organs demonstrating that preconditioning regimens to induce endogenous regenerative mechanisms protect various organs from later incurring acute injuries, we here aimed to gain insights into the molecular mechanisms underlying successful protection and to explore whether such pathways could be utilized to inhibit progression of chronic organ injury. We identified a protective mechanism controlled by the transcription factor ARNT that effectively inhibits progression of chronic kidney injury by transcriptional induction of ALK3, the principal mediator of antifibrotic and proregenerative bone morphogenetic protein-signaling (BMP-signaling) responses. We further report that ARNT expression itself is controlled by the FKBP12/YY1 transcriptional repressor complex and that disruption of such FKBP12/YY1 complexes by picomolar FK506 at subimmunosuppressive doses increases ARNT expression, subsequently leading to homodimeric ARNT-induced ALK3 transcription. Direct targeting of FKBP12/YY1 with in vivo morpholino approaches or small molecule inhibitors, including GPI-1046, was equally effective for inducing ARNT expression, with subsequent activation of ALK3-dependent canonical BMP-signaling responses and attenuated chronic organ failure in models of chronic kidney disease, and also cardiac and liver injuries. In summary, we report an organ-protective mechanism that can be pharmacologically modulated by immunophilin ligands FK506 and GPI-1046 or therapeutically targeted by in vivo morpholino approaches.
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http://dx.doi.org/10.1172/JCI89632DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6025987PMC
July 2018

Low-dose hydralazine prevents fibrosis in a murine model of acute kidney injury-to-chronic kidney disease progression.

Kidney Int 2017 01 28;91(1):157-176. Epub 2016 Sep 28.

Department of Nephrology and Rheumatology, Göttingen University Medical Center, Georg August University, Göttingen, Germany; German Center for Cardiovascular Research, Göttingen, Germany. Electronic address:

Acute kidney injury (AKI) and progressive chronic kidney disease (CKD) are intrinsically tied syndromes. In this regard, the acutely injured kidney often does not achieve its full regenerative capacity and AKI directly transitions into progressive CKD associated with tubulointerstitial fibrosis. Underlying mechanisms of such AKI-to-CKD progression are still incompletely understood and specific therapeutic interventions are still elusive. Because epigenetic modifications play a role in maintaining tissue fibrosis, we used a murine model of ischemia-reperfusion injury to determine whether aberrant promoter methylation of RASAL1 contributes causally to the switch between physiological regeneration and tubulointerstitial fibrogenesis, a hallmark of AKI-to-CKD progression. It is known that the antihypertensive drug hydralazine has demethylating activity, and that its optimum demethylating activity occurs at concentrations below blood pressure-lowering doses. Administration of low-dose hydralazine effectively induced expression of hydroxylase TET3, which catalyzed RASAL1 hydroxymethylation and subsequent RASAL1 promoter demethylation. Hydralazine-induced CpG promoter demethylation subsequently attenuated renal fibrosis and preserved excretory renal function independent of its blood pressure-lowering effects. In comparison, RASAL1 demethylation and inhibition of tubulointerstitial fibrosis was not detected upon administration of the angiotensin-converting enzyme inhibitor Ramipril in this model. Thus, RASAL1 promoter methylation and subsequent transcriptional RASAL1 suppression plays a causal role in AKI-to-CKD progression.
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http://dx.doi.org/10.1016/j.kint.2016.07.042DOI Listing
January 2017

Differentiation of functional endothelial cells from human induced pluripotent stem cells: A novel, highly efficient and cost effective method.

Differentiation 2016 Oct - Nov;92(4):225-236. Epub 2016 Jun 4.

Department of Cardiology and Pneumology, University Medical Center of Göttingen, Georg August University, 37075 Göttingen, Germany; DZHK (German Centre for Cardiovascular Research) Partner Site Göttingen, 37075 Göttingen, Germany. Electronic address:

Endothelial cells derived from human induced pluripotent stem cells (hiPSC- EC) are of significant value for research on human vascular development, in vitro disease models and drug screening. Here we report an alternative, highly efficient and cost-effective simple three step method (mesoderm induction, endothelial cell differentiation and endothelial cell expansion) to differentiate hiPSC directly into endothelial cells. We demonstrate that efficiency of described method to derive CD31+ and VE-Cadherin+ double positive cells is higher than 80% in 12 days. Most notably we established that hiPSC-EC differentiation efficacy depends on optimization of both mesoderm differentiation and endothelial cell differentiation steps.
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http://dx.doi.org/10.1016/j.diff.2016.05.004DOI Listing
August 2017

Hypoxia-induced endothelial-mesenchymal transition is associated with RASAL1 promoter hypermethylation in human coronary endothelial cells.

FEBS Lett 2016 04 21;590(8):1222-33. Epub 2016 Apr 21.

Department of Cardiology and Pneumology, University Medical Center of Göttingen, Georg-August University, Göttingen, Germany.

Cardiac fibrosis is integral in chronic heart disease, and one of the cellular processes contributing to cardiac fibrosis is endothelial-to-mesenchymal transition (EndMT). We recently found that hypoxia efficiently induces human coronary artery endothelial cells (HCAEC) to undergo EndMT through a hypoxia inducible factor-1α (HIF1α)-dependent pathway. Promoter hypermethylation of Ras-Gap-like protein 1 (RASAL1) has also been recently associated with EndMT progression and cardiac fibrosis. Our findings suggest that HIF1α and transforming growth factor (TGF)/SMAD signalling pathways synergistically regulate hypoxia-induced EndMT through both DNMT3a-mediated hypermethylation of RASAL1 promoter and direct SNAIL induction. The findings indicate that multiple cascades may be activated simultaneously to mediate hypoxia-induced EndMT.
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http://dx.doi.org/10.1002/1873-3468.12158DOI Listing
April 2016

DNMT1 and HDAC2 Cooperate to Facilitate Aberrant Promoter Methylation in Inorganic Phosphate-Induced Endothelial-Mesenchymal Transition.

PLoS One 2016 27;11(1):e0147816. Epub 2016 Jan 27.

Department of Cardiology and Pneumology, Göttingen University Medical Center, Georg August University, Göttingen, Germany.

While phosphorus in the form of inorganic or organic phosphate is critically involved in most cellular functions, high plasma levels of inorganic phosphate levels have emerged as independent risk factor for cardiac fibrosis, cardiovascular morbidity and decreased life-expectancy. While the link of high phosphate and cardiovascular disease is commonly explained by direct cellular effects of phospho-regulatory hormones, we here explored the possibility of inorganic phosphate directly eliciting biological responses in cells. We demonstrate that human coronary endothelial cells (HCAEC) undergo an endothelial-mesenchymal transition (EndMT) when exposed to high phosphate. We further demonstrate that such EndMT is initiated by recruitment of aberrantly phosphorylated DNMT1 to the RASAL1 CpG island promoter by HDAC2, causing aberrant promoter methylation and transcriptional suppression, ultimately leading to increased Ras-GTP activity and activation of common EndMT regulators Twist and Snail. Our studies provide a novel aspect for known adverse effects of high phosphate levels, as eukaryotic cells are commonly believed to have lost phosphate-sensing mechanisms of prokaryotes during evolution, rendering them insensitive to extracellular inorganic orthophosphate. In addition, our studies provide novel insights into the mechanisms underlying specific targeting of select genes in context of fibrogenesis.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0147816PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4729486PMC
July 2016

High inorganic phosphate causes DNMT1 phosphorylation and subsequent fibrotic fibroblast activation.

Biochem Biophys Res Commun 2016 Apr 14;472(3):459-64. Epub 2016 Jan 14.

Department of Nephrology and Rheumatology, Göttingen University Medical Center, Georg August University, Göttingen, Germany; German Center for Cardiovascular Research (DZHK), Göttingen, Germany. Electronic address:

Phosphate is an essential constituent of critical cellular functions including energy metabolism, nucleic acid synthesis and phosphorylation-dependent cell signaling. Increased plasma phosphate levels are an independent risk factor for lowered life-expectancy as well as for heart and kidney failure. Nevertheless, direct cellular effects of elevated phosphate concentrations within the microenvironment are poorly understood and have been largely neglected in favor of phosphor-regulatory hormones. Because interstitial fibrosis is the common determinant of chronic progressive kidney disease, and because fibroblasts are major mediators of fibrogenesis, we here explored the effect of high extracellular phosphate levels on renal fibroblasts. We demonstrate that high inorganic phosphate directly induces fibrotic fibroblast activation associated with increased proliferative activity, increased expression of α-smooth muscle actin and increased synthesis of type I collagen. We further demonstrate that such fibroblast activation is dependent on phosphate influx, aberrant phosphorylation of DNA methyltransferase DNMT1 and aberrant CpG island promoter methylation. In summary, our studies demonstrate that elevated phosphate concentrations induce pro-fibrotic fibroblast activation independent of phospho-regulatory hormones.
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http://dx.doi.org/10.1016/j.bbrc.2016.01.077DOI Listing
April 2016

Hepatic Interferon-λ3 (IFNL3) Gene Expression Reveals Not to Be Attenuated in Non-Favorable IFNL3 rs4803217 or IFNL4 rs368234815 Minor Allele Carriers in Chronic Hepatitis C.

PLoS One 2015 25;10(11):e0143783. Epub 2015 Nov 25.

Department of Gastroenterology and Gastrointestinal Oncology, University Medical Center, Georg-August University Goettingen, Goettingen, Germany.

Genetic polymorphisms in the region of the interferon-λ genes (IFNL) associate with clearance of hepatitis C virus (HCV) infection. One of these polymorphisms, IFNL4 rs368234815, determines loss or gain of function of the IFNL4 gene by frameshift variation. The very same and a second one, IFNL3 rs4803217, are supposed to impact the expression of IFNL3: while IFNL4 rs368234815 is suggested to modulate IFNL3 transcription, IFNL3 rs4803217 is thought to alter IFNL3 mRNA stability. The latter process is believed to be partially driven by an HCV-induced ectopic expression of myosin heavy chain genes 7B and 7 and their co-expressed microRNAs mir499 and mir208B. These ideas are evidenced by functional investigations on peripheral blood mononuclear and hepatoma cells in culture. Our study aimed at exploring IFNL3 gene expression in clinical samples, i.e., in ex vivo derived liver tissue from patients with chronic hepatitis C (n = 57) and various other diseases (n = 56). By applying an assay designed to specifically quantify IFNL3 and discriminating paralogous IFNL2 transcripts, IFNL3 mRNA expression was not found to differ significantly between chronic hepatitis C and control samples. Among patients with chronic HCV infection, moreover, IFNL3 rs4803217 or IFNL4 rs368234815 minor alleles did not associate with reduced IFNL3 gene expression. Finally, myosin heavy chain genes 7B and 7 and corresponding microRNAs mir499 and mir208B were not found activated in liver in chronic HCV infection. Of note, detectability of MYH7 mRNA related to the procedure of liver biopsy sampling, as tissue obtained by direct punctation of the liver during laparoscopic inspection was less likely to contain MYH7 transcripts than samples acquired by percutaneous punctation. In conclusion, data on ex vivo derived liver tissue samples argue against an attenuating impact of IFNL3 rs4803217 or IFNL4 rs368234815 minor alleles on hepatic IFNL3 gene expression in vivo.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0143783PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4659612PMC
June 2016

Precision renal medicine: a roadmap towards targeted kidney fibrosis therapies.

Fibrogenesis Tissue Repair 2015 1;8:16. Epub 2015 Sep 1.

Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany ; German Center for Cardiovascular Research (DZHK), Robert Koch Street 40, Göttingen, Germany.

Based on extensive pre-clinical achievements over the past decades, it appears to be due time for a successful clinical translation in the renal fibrosis field-but what is the quickest road to get there? In light of the recent launch of the Precision Medicine Initiative and success of molecularly informed drugs in oncology, we here discuss what it may take to bring molecularly targeted anti-fibrotic to clinical use in chronic progressive kidney disease.
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http://dx.doi.org/10.1186/s13069-015-0033-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4556008PMC
September 2015

Evidence for antifibrotic incretin-independent effects of the DPP-4 inhibitor linagliptin.

Kidney Int 2015 Sep;88(3):429-31

Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg August University, Göttingen, Germany.

Among gliptins, linagliptin is unique, because decreased glomerular filtration rate does not require dose reduction. Linagliptin was originally developed to lower blood glucose by inhibiting dipeptidyl peptidase-4 (DPP-4). However, DPP-4 has numerous additional substrates, and thus gliptins possess a vast range of additional off-target effects. Shi et al. report that linagliptin directly targets interaction of DPP-4 with integrin β1, preventing endothelial-mesenchymal transition and ultimately renal fibrosis, providing additional rationale for use of linagliptin in diabetic nephropathy.
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http://dx.doi.org/10.1038/ki.2015.175DOI Listing
September 2015

Association of circulating angiogenesis inhibitors and asymmetric dimethyl arginine with coronary plaque burden.

Fibrogenesis Tissue Repair 2015 21;8:13. Epub 2015 Jul 21.

Departments of Cardiology and Pneumology, University Medical Center, Georg-August University, Robert-Koch-Str. 40, Göttingen, 37075 Germany ; DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany.

Background: Chronic kidney disease (CKD) is an independent risk factor for the development and severity of coronary artery disease (CHD) and endothelial dysfunction. There is an increase in the circulating angiogenesis inhibitors endostatin (END), thrombospondin-2 (TSP), angiopoietin-2 (ANG) and the nitric oxide (NO) inhibitor asymmetric dimethyl arginine (ADMA) in CKD patients. The aim of this study was to evaluate associations of the serum level of these factors and of the related angiogenesis inhibitor, endoglin (ENG), with burden of coronary atherosclerosis.

Methods: One hundred twenty-two patients undergoing coronary angiography were recruited from the cardiac catheterization lab at a single center. The total burden of coronary plaque (mm(2)) and the presence of coronary collaterals were quantified using quantitative coronary angiography (QCA). Serum levels of angiogenesis inhibitors were measured by ELISA (ENG, END, and ANG), Luminex assay (TSP), or HLPC (ADMA), respectively. Associations with plaque burden and coronary collateral supply were analyzed in multi-variable linear and logistic regression models.

Results: There was no significant association found between levels of circulating ADMA, ENG, END, ANG, or TSP and coronary plaque burden or collateral formation.

Conclusions: Our findings suggest that associations of circulating END, ENG, TSP, and ANG with cardiovascular mortality are unlikely to be mediated via direct effects on coronary plaque formation or by inhibition of collateral formation. Whether associations of these factors with mortality are mediated via local concentrations, myocardial tissue, or intra-plaque expression of these factors or by an effect on plaque vulnerability merits additional investigation.
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http://dx.doi.org/10.1186/s13069-015-0029-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4514965PMC
July 2015

Snail Is a Direct Target of Hypoxia-inducible Factor 1α (HIF1α) in Hypoxia-induced Endothelial to Mesenchymal Transition of Human Coronary Endothelial Cells.

J Biol Chem 2015 Jul 13;290(27):16653-64. Epub 2015 May 13.

From the Departments of Cardiology and Pneumology and DZHK (German Centre for Cardiovascular Research) partner site, 37075 Göttingen, Germany

Endothelial to mesenchymal transition (EndMT) was originally described in heart development where the endocardial endothelial cells that line the atrioventricular canal undergo an EndMT to form the endocardial mesenchymal cushion that later gives rise to the septum and mitral and tricuspid valves. In the postnatal heart specifically, endothelial cells that originate from the endocardium maintain increased susceptibility to undergo EndMT as remnants from their embryonic origin. Such EndMT involving adult coronary endothelial cells contributes to microvascular rarefaction and subsequent chronification of hypoxia in the injured heart, ultimately leading to cardiac fibrosis. Although in most endothelial beds hypoxia induces tip cell formation and sprouting angiogenesis, here we demonstrate that hypoxia is a stimulus for human coronary endothelial cells to undergo phenotypic changes reminiscent of EndMT via a mechanism involving hypoxia-inducible factor 1α-induced activation of the EndMT master regulatory transcription factor SNAIL. Our study adds further evidence for the unique susceptibility of endocardium-derived endothelial cells to undergo EndMT and provides novel insights into how hypoxia contributes to progression of cardiac fibrosis. Additional studies may be required to discriminate between distinct sprouting angiogenesis and EndMT responses of different endothelial cells populations.
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http://dx.doi.org/10.1074/jbc.M115.636944DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4505417PMC
July 2015

Association of activated vitamin D use with myocardial fibrosis and capillary supply: results of an autopsy study.

Ren Fail 2015 Jul 8;37(6):1067-9. Epub 2015 May 8.

c Department of Cardiology and Pneumology , University Medical Center, Georg-August University , Göttingen , Germany , and.

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http://dx.doi.org/10.3109/0886022X.2015.1040704DOI Listing
July 2015

Induction of Tet3-dependent Epigenetic Remodeling by Low-dose Hydralazine Attenuates Progression of Chronic Kidney Disease.

EBioMedicine 2015 Jan;2(1):19-36

Department of Nephrology and Rheumatology, Göttingen University Medical Center, Georg August University, Robert Koch Street 40, Göttingen, Germany ; Division of Matrix Biology, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Ave, Boston, MA, USA.

Progression of chronic kidney disease remains a principal problem in clinical nephrology and there is a pressing need for novel therapeutics and biomarkers. Aberrant promoter CpG island methylation and subsequent transcriptional silencing of specific genes have emerged as contributors to progression of chronic kidney disease. Here, we report that transcriptional silencing of the Ras-GTP suppressor RASAL1 contributes causally to progression of kidney fibrosis and we identified that circulating methylated promoter DNA fragments in peripheral blood correspond with levels of intrarenal levels of promoter methylation and degree of fibrosis in kidney biopsies, enabling non-invasive longitudinal analysis of intrarenal CpG island methylation.
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http://dx.doi.org/10.1016/j.ebiom.2014.11.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4337426PMC
January 2015

Endothelial p53 deletion improves angiogenesis and prevents cardiac fibrosis and heart failure induced by pressure overload in mice.

J Am Heart Assoc 2015 Feb 24;4(2). Epub 2015 Feb 24.

Department of Cardiology and Pneumology, University Medical Center Göttingen, Germany (R.G., X.X., J.H.S., S.E.L., E.M.Z., K.S.) Division of Cardiology, Department of Medicine 2, University Medical Center Mainz, Germany (M.L.B., P.W., K.S.) German Center for Cardiovascular Research (DZHK), University of Maryland Baltimore, MD (S.E.L., E.M.Z., K.S.).

Background: Cardiac dysfunction developing in response to chronic pressure overload is associated with apoptotic cell death and myocardial vessel rarefaction. We examined whether deletion of tumor suppressor p53 in endothelial cells may prevent the transition from cardiac hypertrophy to heart failure.

Methods And Results: Mice with endothelial-specific deletion of p53 (End.p53-KO) were generated by crossing p53fl/fl mice with mice expressing Cre recombinase under control of an inducible Tie2 promoter. Cardiac hypertrophy was induced by transverse aortic constriction. Serial echocardiography measurements revealed improved cardiac function in End.p53-KO mice that also exhibited better survival. Cardiac hypertrophy was associated with increased p53 levels in End.p53-WT controls, whereas banded hearts of End.p53-KO mice exhibited lower numbers of apoptotic endothelial and non-endothelial cells and altered mRNA levels of genes regulating cell cycle progression (p21), apoptosis (Puma), or proliferation (Pcna). A higher cardiac capillary density and improved myocardial perfusion was observed, and pharmacological inhibition or genetic deletion of p53 also promoted endothelial sprouting in vitro and new vessel formation following hindlimb ischemia in vivo. Hearts of End.p53-KO mice exhibited markedly less fibrosis compared with End.p53-WT controls, and lower mRNA levels of p53-regulated genes involved in extracellular matrix production and turnover (eg, Bmp-7, Ctgf, or Pai-1), or of transcription factors involved in controlling mesenchymal differentiation were observed.

Conclusions: Our analyses reveal that accumulation of p53 in endothelial cells contributes to blood vessel rarefaction and fibrosis during chronic cardiac pressure overload and suggest that endothelial cells may be a therapeutic target for preserving cardiac function during hypertrophy.
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http://dx.doi.org/10.1161/JAHA.115.001770DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4345879PMC
February 2015

Epigenetic balance of aberrant Rasal1 promoter methylation and hydroxymethylation regulates cardiac fibrosis.

Cardiovasc Res 2015 Mar 23;105(3):279-91. Epub 2015 Jan 23.

Department of Cardiology and Pneumology, University Medical Center of Göttingen, Georg-August University, Robert-Koch-Str. 40, 37075 Göttingen, Germany German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany

Aims: Methylation of CpG island promoters is a prototypical epigenetic mechanism to stably control gene expression. The aim of this study was to elucidate the contribution of aberrant promoter DNA methylation in pathological endothelial to mesenchymal transition (EndMT) and subsequent cardiac fibrosis.

Methods And Results: In human coronary endothelial cells, TGFβ1 causes aberrant methylation of RASAL1 promoter, increased Ras-GTP activity, and EndMT. In end-stage failing vs. non-failing human myocardium, increased fibrosis was associated with significantly increased RASAL1 promoter methylation, decreased RASAL1 expression, increased Ras-GTP activity, and increased expression of markers of EndMT. In mice with pressure overload due to ascending aortic constriction, BMP7 significantly reduced RASAL1 promoter methylation, increased RASAL1 expression, and decreased EndMT markers as well as decreased cardiac fibrosis. The ten eleven translocation (TET) family enzyme TET3, which demethylates through hydroxymethylation, was significantly decreased in fibrotic mouse hearts, restored with BMP7, and BMP7 effects were absent in coronary endothelial cells with siRNA knockdown of TET3.

Conclusion: Our study provides proof-in-principle evidence that transcriptional suppression of RASAL1 through aberrant promoter methylation contributes to EndMT and ultimately to progression of cardiac fibrosis. Such aberrant methylation can be reversed through Tet3-mediated hydroxymethylation, which can be specifically induced by BMP7. This may reflect a new treatment strategy to stop cardiac fibrosis.
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http://dx.doi.org/10.1093/cvr/cvv015DOI Listing
March 2015

Endocardial fibroelastosis is caused by aberrant endothelial to mesenchymal transition.

Circ Res 2015 Feb 13;116(5):857-66. Epub 2015 Jan 13.

From the Department of Cardiology and Pneumology (X.X., F.A., E.M.Z.), Department of Nephrology and Rheumatology (B.T., M.Z.), University Medical Center of Göttingen, Georg-August University, Göttingen, Germany; Department of Cardiac Surgery, Boston Children's Hospital, Harvard Medical School, MA (I.F., I.V., P.J.d N.); Division of Matrix Biology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (T.Z.H., R.K., E.M.Z.); Lab Genetica Molecolare, Papa Giovanni XXIII Hospital, Bergamo, Italy (M.I.); Department of Cancer Biology and the Metastasis Research Center, University of Texas MD Anderson Cancer Center, Houston (R.K.); and DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany (E.M.Z.).

Rationale: Endocardial fibroelastosis (EFE) is a unique form of fibrosis, which forms a de novo subendocardial tissue layer encapsulating the myocardium and stunting its growth, and which is typically associated with congenital heart diseases of heterogeneous origin, such as hypoplastic left heart syndrome. Relevance of EFE was only recently highlighted through the establishment of staged biventricular repair surgery in infant patients with hypoplastic left heart syndrome, where surgical removal of EFE tissue has resulted in improvement in the restrictive physiology leading to the growth of the left ventricle in parallel with somatic growth. However, pathomechanisms underlying EFE formation are still scarce, and specific therapeutic targets are not yet known.

Objective: Here, we aimed to investigate the cellular origins of EFE tissue and to gain insights into the underlying molecular mechanisms to ultimately develop novel therapeutic strategies.

Methods And Results: By utilizing a novel EFE model of heterotopic transplantation of hearts from newborn reporter mice and by analyzing human EFE tissue, we demonstrate for the first time that fibrogenic cells within EFE tissue originate from endocardial endothelial cells via aberrant endothelial to mesenchymal transition. We further demonstrate that such aberrant endothelial to mesenchymal transition involving endocardial endothelial cells is caused by dysregulated transforming growth factor beta/bone morphogenetic proteins signaling and that this imbalance is at least in part caused by aberrant promoter methylation and subsequent transcriptional suppression of bone morphogenetic proteins 5 and 7. Finally, we provide evidence that supplementation of exogenous recombinant bone morphogenetic proteins 7 effectively ameliorates endothelial to mesenchymal transition and experimental EFE in rats.

Conclusions: In summary, our data point to aberrant endothelial to mesenchymal transition as a common denominator of infant EFE development in heterogeneous, congenital heart diseases, and to bone morphogenetic proteins 7 as an effective treatment for EFE and its restriction of heart growth.
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http://dx.doi.org/10.1161/CIRCRESAHA.116.305629DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4344885PMC
February 2015

Thrombospondin-1 deficiency causes a shift from fibroproliferative to inflammatory kidney disease and delays onset of renal failure.

Am J Pathol 2014 Oct 10;184(10):2687-98. Epub 2014 Aug 10.

Division of Matrix Biology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts; Department of Cancer Biology and the Metastasis Research Center, University of Texas MD Anderson Cancer Center, Houston, Texas. Electronic address:

Thrombospondin-1 (TSP1) is a multifunctional matricellular protein known to promote progression of chronic kidney disease. To gain insight into the underlying mechanisms through which TSP1 accelerates chronic kidney disease, we compared disease progression in Col4a3 knockout (KO) mice, which develop spontaneous kidney failure, with that of Col4a3;Tsp1 double-knockout (DKO) mice. Decline of excretory renal function was significantly delayed in the absence of TSP1. Although Col4a3;Tsp1 DKO mice did progress toward end-stage renal failure, their kidneys exhibited distinct histopathological lesions, compared with creatinine level-matched Col4a3 KO mice. Although kidneys of both Col4a3 KO and Col4a3;Tsp1 DKO mice exhibited a widened tubulointerstitium, predominant lesions in Col4a3 KO kidneys were collagen deposition and fibroblast accumulation, whereas in Col4a3;Tsp1 DKO kidney inflammation was predominant, with less collagen deposition. Altered disease progression correlated with impaired activation of transforming growth factor-β1 (TGF-β1) in vivo and in vitro in the absence of TSP1. In summary, our findings suggest that TSP1 contributes to progression of chronic kidney disease by catalyzing activation of latent TGF-β1, resulting in promotion of a fibroproliferative response over an inflammatory response. Furthermore, the findings suggest that fibroproliferative and inflammatory lesions are independent entities, both of which contribute to decline of renal function.
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http://dx.doi.org/10.1016/j.ajpath.2014.06.014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4715225PMC
October 2014

Increased concentration of circulating angiogenesis and nitric oxide inhibitors induces endothelial to mesenchymal transition and myocardial fibrosis in patients with chronic kidney disease.

Int J Cardiol 2014 Sep 6;176(1):99-109. Epub 2014 Jul 6.

Department of Cardiology and Pneumology, University Medical Center, Georg-August University, Göttingen, Germany; DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany.

Background: Sudden cardiovascular death is increased in chronic kidney disease (CKD). Experimental CKD models suggest that angiogenesis and nitric oxide (NO) inhibitors induce myocardial fibrosis and microvascular dropout thereby facilitating arrhythmogenesis. We undertook this study to characterize associations of CKD with human myocardial pathology, NO-related circulating angiogenesis inhibitors, and endothelial cell behavior.

Methods: We compared heart (n=54) and serum (n=162) samples from individuals with and without CKD, and assessed effects of serum on human coronary artery endothelial cells (HCAECs) in vitro. Left ventricular fibrosis and capillary density were quantified in post-mortem samples. Endothelial to mesenchymal transition (EndMT) was assessed by immunostaining of post-mortem samples and RNA expression in heart tissue obtained during cardiac surgery. Circulating asymmetric dimethylarginine (ADMA), endostatin (END), angiopoietin-2 (ANG), and thrombospondin-2 (TSP) were measured, and the effect of these factors and of subject serum on proliferation, apoptosis, and EndMT of HCAEC was analyzed.

Results: Cardiac fibrosis increased 12% and 77% in stage 3-4 CKD and ESRD and microvascular density decreased 12% and 16% vs. preserved renal function. EndMT-derived fibroblast proportion was 17% higher in stage 3-4 CKD and ESRD (P trend = 0.02). ADMA, ANG, TSP, and END concentrations increased in CKD. Both individual factors and CKD serum increased HCAEC apoptosis (P=0.02), decreased proliferation (P=0.03), and induced EndMT.

Conclusions: CKD is associated with an increase in circulating angiogenesis and NO inhibitors, which impact proliferation and apoptosis of cardiac endothelial cells and promote EndMT, leading to cardiac fibrosis and capillary rarefaction. These processes may play key roles in CKD-associated CV disease.
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http://dx.doi.org/10.1016/j.ijcard.2014.06.062DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4161362PMC
September 2014

Tet3-mediated hydroxymethylation of epigenetically silenced genes contributes to bone morphogenic protein 7-induced reversal of kidney fibrosis.

J Am Soc Nephrol 2014 May 30;25(5):905-12. Epub 2014 Jan 30.

Departments of Nephrology and Rheumatology, and

Methylation of CpG island promoters is an epigenetic event that can effectively silence transcription over multiple cell generations. Hypermethylation of the Rasal1 promoter contributes to activation of fibroblasts and progression of kidney fibrosis. Here, we explored whether such causative hypermethylation could be reversed through endogenous mechanisms and whether such reversal of hypermethylation is a constituent of the antifibrotic activity of bone morphogenic protein 7 (BMP7). We show that successful inhibition of experimental kidney fibrosis through administration of BMP7 associates with normalization of Rasal1 promoter hypermethylation. Furthermore, this reversal of pathologic hypermethylation was achieved specifically through Tet3-mediated hydroxymethylation. Collectively, our findings reveal a new mechanism that may be exploited to facilitate therapeutic DNA demethylation to reverse kidney fibrosis.
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http://dx.doi.org/10.1681/ASN.2013070723DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4005308PMC
May 2014

The role of promoter hypermethylation in fibroblast activation and fibrogenesis.

J Pathol 2013 Jan;229(2):264-73

Department of Cardiology and Pneumology, Göttingen University Medical Centre, Georg August University, Göttingen, Germany.

The aberrant methylation of CpG island promoters of selected genes is the prominent epigenetic mechanism by which gene transcription can be effectively silenced. Aberrant hypermethylation of a few selected genes plays an important role in facilitating fibrotic fibroblast activation and in driving fibrogenesis. Here we review mechanisms of DNA methylation and demethylation and their implications for fibroblast activation and tissue fibrosis.
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http://dx.doi.org/10.1002/path.4120DOI Listing
January 2013