Publications by authors named "Monica Ventura Ferreira"

21 Publications

  • Page 1 of 1

Cord blood telomere shortening associates with increased gestational age and birth weight in preterm neonates.

Exp Ther Med 2021 Apr 10;21(4):344. Epub 2021 Feb 10.

Department of Hematology, Oncology, Hemostaseology and Stem Cell Transplantation, Medical Faculty, RWTH Aachen University, D-52062 Aachen, Germany.

Preterm birth is considered to be associated with premature cellular aging. To address this question, two hallmarks of aging were analyzed in cord blood cells, namely telomere length and age-associated DNA methylation. Cord blood samples from 35 preterm and 11 full-term neonates were enrolled in the present study. Furthermore, quantitative telomere fluorescence hybridization and flow cytometry (flow-FISH) were applied to demonstrate that telomere shortening was strongly associated with advanced gestational age and increased birth weight (R=0.267 for granulocytes and R=0.307 for lymphocytes). The estimated rate of telomere attrition in newborns during gestation ranged from 126 base pairs (bp)/week and 186 bp/week for granulocytes and lymphocytes, respectively. In addition, neonates with longer telomeres at birth were characterized by increased weight gain during the first year of their life compared with that noted to neonates with shorter telomeres. By contrast, the epigenetic aging signature (EAS) revealed a negative correlation between epigenetic age and premature birth of unclear basis (R=0.26). Pending prospective validation in a larger patient cohort, the present study suggested that telomere length may be a novel biomarker alone or in combination with traditional indicators for the prediction of weight development in preterm neonates.
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http://dx.doi.org/10.3892/etm.2021.9775DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7903469PMC
April 2021

Clonal hematopoiesis in donors and long-term survivors of related allogeneic hematopoietic stem cell transplantation.

Blood 2020 04;135(18):1548-1559

Department of Medical Oncology and Hematology, University of Zurich and University Hospital Zurich, Zurich, Switzerland.

Clonal hematopoiesis (CH) is associated with age and an increased risk of myeloid malignancies, cardiovascular risk, and all-cause mortality. We tested for CH in a setting where hematopoietic stem cells (HSCs) of the same individual are exposed to different degrees of proliferative stress and environments, ie, in long-term survivors of allogeneic hematopoietic stem cell transplantation (allo-HSCT) and their respective related donors (n = 42 donor-recipient pairs). With a median follow-up time since allo-HSCT of 16 years (range, 10-32 years), we found a total of 35 mutations in 23 out of 84 (27.4%) study participants. Ten out of 42 donors (23.8%) and 13 out of 42 recipients (31%) had CH. CH was associated with older donor and recipient age. We identified 5 cases of donor-engrafted CH, with 1 case progressing into myelodysplastic syndrome in both donor and recipient. Four out of 5 cases showed increased clone size in recipients compared with donors. We further characterized the hematopoietic system in individuals with CH as follows: (1) CH was consistently present in myeloid cells but varied in penetrance in B and T cells; (2) colony-forming units (CFUs) revealed clonal evolution or multiple independent clones in individuals with multiple CH mutations; and (3) telomere shortening determined in granulocytes suggested ∼20 years of added proliferative history of HSCs in recipients compared with their donors, with telomere length in CH vs non-CH CFUs showing varying patterns. This study provides insight into the long-term behavior of the same human HSCs and respective CH development under different proliferative conditions.
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http://dx.doi.org/10.1182/blood.2019003079DOI Listing
April 2020

Fibrosis in tissue engineering and regenerative medicine: treat or trigger?

Adv Drug Deliv Rev 2019 06 8;146:17-36. Epub 2019 Jul 8.

Department of Biohybrid & Medical Textiles (BioTex), AME - Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Forckenbeckstr. 55, 52074 Aachen, Germany; Medical Materials and Implants, Department of Mechanical Engineering, Technical University of Munich, Boltzmannstr. 15, 85748 Garching, Germany. Electronic address:

Fibrosis is a life-threatening pathological condition resulting from a dysfunctional tissue repair process. There is no efficient treatment and organ transplantation is in many cases the only therapeutic option. Here we review tissue engineering and regenerative medicine (TERM) approaches to address fibrosis in the cardiovascular system, the kidney, the lung and the liver. These strategies have great potential to achieve repair or replacement of diseased organs by cell- and material-based therapies. However, paradoxically, they might also trigger fibrosis. Cases of TERM interventions with adverse outcome are also included in this review. Furthermore, we emphasize the fact that, although organ engineering is still in its infancy, the advances in the field are leading to biomedically relevant in vitro models with tremendous potential for disease recapitulation and development of therapies. These human tissue models might have increased predictive power for human drug responses thereby reducing the need for animal testing.
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http://dx.doi.org/10.1016/j.addr.2019.07.007DOI Listing
June 2019

Rps14, Csnk1a1 and miRNA145/miRNA146a deficiency cooperate in the clinical phenotype and activation of the innate immune system in the 5q- syndrome.

Leukemia 2019 07 16;33(7):1759-1772. Epub 2019 Jan 16.

Department of Hematology, Oncology, Hemostaseology, and Stem Cell Transplantation, RWTH Aachen University, Aachen, Germany.

RPS14, CSNK1A1, and miR-145 are universally co-deleted in the 5q- syndrome, but mouse models of each gene deficiency recapitulate only a subset of the composite clinical features. We analyzed the combinatorial effect of haploinsufficiency for Rps14, Csnk1a1, and miRNA-145, using mice with genetically engineered, conditional heterozygous inactivation of Rps14 and Csnk1a1 and stable knockdown of miR-145/miR-146a. Combined Rps14/Csnk1a1/miR-145/146a deficiency recapitulated the cardinal features of the 5q- syndrome, including (1) more severe anemia with faster kinetics than Rps14 haploinsufficiency alone and (2) pathognomonic megakaryocyte morphology. Macrophages, regulatory cells of erythropoiesis and the innate immune response, were significantly increased in Rps14/Csnk1a1/miR-145/146a deficient mice as well as in 5q- syndrome patient bone marrows and showed activation of the innate immune response, reflected by increased expression of S100A8, and decreased phagocytic function. We demonstrate that Rps14/Csnk1a1/miR-145 and miR-146a deficient macrophages alter the microenvironment and induce S100A8 expression in the mesenchymal stem cell niche. The increased S100A8 expression in the mesenchymal niche was confirmed in 5q- syndrome patients. These data indicate that intrinsic defects of the 5q- syndrome hematopoietic stem cell directly alter the surrounding microenvironment, which in turn affects hematopoiesis as an extrinsic mechanism.
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http://dx.doi.org/10.1038/s41375-018-0350-3DOI Listing
July 2019

Telomere shortening correlates with leukemic stem cell burden at diagnosis of chronic myeloid leukemia.

Blood Adv 2018 07;2(13):1572-1579

Department of Hematology, Oncology, Hemostaseology, and Stem Cell Transplantation, Medical Faculty, RWTH Aachen University, Aachen, Germany.

Telomere length (TL) in peripheral blood (PB) cells of patients with chronic myeloid leukemia (CML) has been shown to correlate with disease stage, prognostic scores, response to therapy, and disease progression. However, due to considerable genetic interindividual variability, TL varies substantially between individuals, limiting its use as a robust prognostic marker in individual patients. Here, we compared TL of BCR-ABL, nonleukemic CD34CD38 hematopoietic stem cells (HSC) in the bone marrow of CML patients at diagnosis to their individual BCR-ABL leukemic stem cell (LSC) counterparts. We observed significantly accelerated telomere shortening in LSC compared with nonleukemic HSC. Interestingly, the degree of LSC telomere shortening was found to correlate significantly with the leukemic clone size. To validate the diagnostic value of nonleukemic cells as internal controls and to rule out effects of tyrosine kinase inhibitor (TKI) treatment on these nontarget cells, we prospectively assessed TL in 134 PB samples collected in deep molecular remission after TKI treatment within the EURO-SKI study (NCT01596114). Here, no significant telomere shortening was observed in granulocytes compared with an age-adjusted control cohort. In conclusion, this study provides proof of principle for accelerated telomere shortening in LSC as opposed to HSC in CML patients at diagnosis. The fact that the degree of telomere shortening correlates with leukemic clone's size supports the use of TL in leukemic cells as a prognostic parameter pending prospective validation. TL in nonleukemic myeloid cells seems unaffected even by long-term TKI treatment arguing against a reduction of telomere-mediated replicative reserve in normal hematopoiesis under TKI treatment.
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http://dx.doi.org/10.1182/bloodadvances.2018017772DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6039661PMC
July 2018

CD57 identifies T cells with functional senescence before terminal differentiation and relative telomere shortening in patients with activated PI3 kinase delta syndrome.

Immunol Cell Biol 2018 11 14;96(10):1060-1071. Epub 2018 Jun 14.

Center for Chronic Immunodeficiency, Medical Center - University of Freiburg, Freiburg, Germany.

Premature T-cell immunosenescence with CD57 CD8 T-cell accumulation has been linked to immunodeficiency and autoimmunity in primary immunodeficiencies including activated PI3 kinase delta syndrome (APDS). To address whether CD57 marks the typical senescent T-cell population seen in adult individuals or identifies a distinct population in APDS, we compared CD57 CD8 T cells from mostly pediatric APDS patients to those of healthy adults with similarly prominent senescent T cells. CD57 CD8 T cells from APDS patients were less differentiated with more CD27 CD28 effector memory T cells showing increased PD1 and Eomesodermin expression. In addition, transition of naïve to CD57 CD8 T cells was not associated with the characteristic telomere shortening. Nevertheless, they showed the increased interferon-gamma secretion, enhanced degranulation and reduced in vitro proliferation typical of senescent CD57 CD8 T cells. Thus, hyperactive PI3 kinase signaling favors premature accumulation of a CD57 CD8 T-cell population, which shows most functional features of typical senescent T cells, but is different in terms of differentiation and relative telomere shortening. Initial observations indicate that this specific differentiation state may offer the opportunity to revert premature T-cell immunosenescence and its potential contribution to inflammation and immunodeficiency in APDS.
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http://dx.doi.org/10.1111/imcb.12169DOI Listing
November 2018

Recurrent somatic mutations are rare in patients with cryptic dyskeratosis congenita.

Leukemia 2018 08 2;32(8):1762-1767. Epub 2018 Apr 2.

Department of Hematology, Oncology, Hemostaseology and Stem Cell Transplantation, Medical Faculty, RWTH Aachen University, Aachen, Germany.

Dyskeratosis congenita (DKC) is a paradigmatic telomere disorder characterized by substantial and premature telomere shortening, bone marrow failure, and a dramatically increased risk of developing myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). DKC can occur as a late-onset, so-called cryptic form, with first manifestation in adults. Somatic MDS-related mutations are found in up to 35% of patients with acquired aplastic anemia (AA), especially in patients with short telomeres. The aim of our study was to investigate whether cryptic DKC is associated with an increased incidence of MDS-related somatic mutations, thereby linking the accelerated telomere shortening with the increased risk of MDS/AML. Samples from 15 adult patients (median age: 42 years, range: 23-60 years) with molecularly confirmed cryptic DKC were screened using next-generation gene panel sequencing to detect MDS-related somatic variants. Only one of the 15 patients (7%) demonstrated a clinically relevant MDS-related somatic variant. This incidence was dramatically lower than formerly described in acquired AA. Based on our data, we conclude that clonal evolution of subclones carrying MDS-related mutations is not the predominant mechanism for MDS/AML initiation in adult cryptic DKC patients.
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http://dx.doi.org/10.1038/s41375-018-0125-xDOI Listing
August 2018

Effects of senolytic drugs on human mesenchymal stromal cells.

Stem Cell Res Ther 2018 04 18;9(1):108. Epub 2018 Apr 18.

Helmholtz-Institute for Biomedical Engineering, Stem Cell Biology and Cellular Engineering, RWTH Aachen University Medical School, Pauwelsstraße 20, 52074, Aachen, Germany.

Background: Senolytic drugs are thought to target senescent cells and might thereby rejuvenate tissues. In fact, such compounds were suggested to increase health and lifespan in various murine aging models. So far, effects of senolytic drugs have not been analysed during replicative senescence of human mesenchymal stromal cells (MSCs).

Methods: In this study, we tested four potentially senolytic drugs: ABT-263 (navitoclax), quercetin, nicotinamide riboside, and danazol. The effects of these compounds were analysed during long-term expansion of MSCs, until replicative senescence. Furthermore, we determined the effect on molecular markers for replicative senescence, such as senescence-associated beta-galactosidase staining (SA-β-gal), telomere attrition, and senescence-associated DNA methylation changes.

Results: Co-culture experiments of fluorescently labelled early and late passages revealed that particularly ABT-263 had a significant but moderate senolytic effect. This was in line with reduced SA-β-gal staining in senescent MSCs upon treatment with ABT-263. However, none of the drugs had significant effects on the maximum number of population doublings, telomere length, or epigenetic senescence predictions.

Conclusions: Of the four tested drugs, only ABT-263 revealed a senolytic effect in human MSCs-and even treatment with this compound did not rejuvenate MSCs with regard to telomere length or epigenetic senescence signature. It will be important to identify more potent senolytic drugs to meet the high hopes for regenerative medicine.
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http://dx.doi.org/10.1186/s13287-018-0857-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5907463PMC
April 2018

Comprehensive characterization of chorionic villi-derived mesenchymal stromal cells from human placenta.

Stem Cell Res Ther 2018 02 5;9(1):28. Epub 2018 Feb 5.

Institute of Pathology, RWTH Aachen University, Aachen, Germany.

Background: Studies in which mesenchymal stromal cells (MSC) from the placenta are compared with multiple MSC types from other sources are rare. The chorionic plate of the human placenta is mainly composed of fetal blood vessels embedded in fetal stroma tissue, lined by trophoblastic cells and organized into chorionic villi (CV) structures.

Methods: We comprehensively characterized human MSC collected from postnatal human chorionic villi of placenta (CV-MSC) by analyzing their growth and proliferation potential, differentiation, immunophenotype, extracellular matrix production, telomere length, aging phenotype, and plasticity.

Results: Immunophenotypic characterization of CV-MSC confirmed the typical MSC marker expression as defined by the International Society for Cellular Therapy. The surface marker profile was consistent with increased potential for proliferation, vascular localization, and early myogenic marker expression. CV-MSC retained multilineage differentiation potential and extracellular matrix remodeling properties. They have undergone reduced telomere loss and delayed onset of cellular senescence as they aged in vitro compared to three other MSC sources. We present evidence that increased human telomerase reverse transcriptase gene expression could not explain the exceptional telomere maintenance and senescence onset delay in cultured CV-MSC. Our in-vitro tumorigenesis detection assay suggests that CV-MSC are not prone to undergo malignant transformation during long-term in-vitro culture. Besides SOX2 expression, no other pluripotency features were observed in early and late passages of CV-MSC.

Conclusions: Our work brings forward two remarkable characteristics of CV-MSC, the first being their extended life span as a result of delayed replicative senescence and the second being a delayed aged phenotype characterized by improved telomere length maintenance. MSC from human placenta are very attractive candidates for stem cell-based therapy applications.
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http://dx.doi.org/10.1186/s13287-017-0757-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5800083PMC
February 2018

Evidence for a pre-existing telomere deficit in non-clonal hematopoietic stem cells in patients with acute myeloid leukemia.

Ann Hematol 2017 Sep 3;96(9):1457-1461. Epub 2017 Jul 3.

Department of Hematology, Oncology, Haemostaseology and Stem Cell Transplantation, RWTH Aachen University Medical Faculty, Aachen, Germany.

Telomere shortening represents an established mechanism connecting aging and cancer development. We sequentially analyzed telomere length (TL) of 49 acute myeloid leukemia (AML) patients at diagnosis (n = 24), once they achieved complete cytological remission (CCR) and/or during refractory disease or relapse and after 1-year follow-up, with all patients having at least two sequential samples. TL was analyzed by monochrome multiplex quantitative polymerase chain reaction. We have observed substantially shortened TL in the cells of patients at diagnosis compared to age-adjusted controls. In patients reaching CCR after chemotherapy, telomere shortening was less pronounced than in persistence or relapse but still significantly shortened compared to controls. We estimate patients harboring approximately 20 years of premature telomere loss compared to healthy aged-matched subjects at the time of AML onset. Our data indicate a pre-existing telomere deficit in non-clonal hematopoiesis of AML patients providing a link between age and AML development.
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http://dx.doi.org/10.1007/s00277-017-3049-zDOI Listing
September 2017

Gli1 Mesenchymal Stromal Cells Are a Key Driver of Bone Marrow Fibrosis and an Important Cellular Therapeutic Target.

Cell Stem Cell 2017 06 27;20(6):785-800.e8. Epub 2017 Apr 27.

Division of Nephrology and Clinical Immunology, RWTH Aachen University, 52074 Aachen, Germany. Electronic address:

Bone marrow fibrosis (BMF) develops in various hematological and non-hematological conditions and is a central pathological feature of myelofibrosis. Effective cell-targeted therapeutics are needed, but the cellular origin of BMF remains elusive. Here, we show using genetic fate tracing in two murine models of BMF that Gli1 mesenchymal stromal cells (MSCs) are recruited from the endosteal and perivascular niche to become fibrosis-driving myofibroblasts in the bone marrow. Genetic ablation of Gli1 cells abolished BMF and rescued bone marrow failure. Pharmacological targeting of Gli proteins with GANT61 inhibited Gli1 cell expansion and myofibroblast differentiation and attenuated fibrosis severity. The same pathway is also active in human BMF, and Gli1 expression in BMF significantly correlates with the severity of the disease. In addition, GANT61 treatment reduced the myofibroblastic phenotype of human MSCs isolated from patients with BMF, suggesting that targeting of Gli proteins could be a relevant therapeutic strategy.
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http://dx.doi.org/10.1016/j.stem.2017.03.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6485654PMC
June 2017

Rps14 haploinsufficiency causes a block in erythroid differentiation mediated by S100A8 and S100A9.

Nat Med 2016 Mar 15;22(3):288-97. Epub 2016 Feb 15.

Division of Hematology, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.

Impaired erythropoiesis in the deletion 5q (del(5q)) subtype of myelodysplastic syndrome (MDS) has been linked to heterozygous deletion of RPS14, which encodes the ribosomal protein small subunit 14. We generated mice with conditional inactivation of Rps14 and demonstrated an erythroid differentiation defect that is dependent on the tumor suppressor protein p53 (encoded by Trp53 in mice) and is characterized by apoptosis at the transition from polychromatic to orthochromatic erythroblasts. This defect resulted in age-dependent progressive anemia, megakaryocyte dysplasia and loss of hematopoietic stem cell (HSC) quiescence. As assessed by quantitative proteomics, mutant erythroblasts expressed higher levels of proteins involved in innate immune signaling, notably the heterodimeric S100 calcium-binding proteins S100a8 and S100a9. S100a8--whose expression was increased in mutant erythroblasts, monocytes and macrophages--is functionally involved in the erythroid defect caused by the Rps14 deletion, as addition of recombinant S100a8 was sufficient to induce a differentiation defect in wild-type erythroid cells, and genetic inactivation of S100a8 expression rescued the erythroid differentiation defect of Rps14-haploinsufficient HSCs. Our data link Rps14 haploinsufficiency in del(5q) MDS to activation of the innate immune system and induction of S100A8-S100A9 expression, leading to a p53-dependent erythroid differentiation defect.
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http://dx.doi.org/10.1038/nm.4047DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4870050PMC
March 2016

An engineered multicomponent bone marrow niche for the recapitulation of hematopoiesis at ectopic transplantation sites.

J Hematol Oncol 2016 Jan 25;9. Epub 2016 Jan 25.

Department of Hematology, Oncology, Hemostaseology and Stem Cell Transplantation, University Hospital Aachen, RWTH Aachen University, Aachen, Germany.

Background: Bone marrow (BM) niches are often inaccessible for controlled experimentation due to their difficult accessibility, biological complexity, and three-dimensional (3D) geometry.

Methods: Here, we report the development and characterization of a BM model comprising of cellular and structural components with increased potential for hematopoietic recapitulation at ectopic transplantation sites. Cellular components included mesenchymal stromal cells (MSCs) and hematopoietic stem and progenitor cells (HSPCs). Structural components included 3D β-tricalcium phosphate (β-TCP) scaffolds complemented with Matrigel or collagen I/III gels for the recreation of the osteogenic/extracellular character of native BM.

Results: In vitro, β-TCP/Matrigel combinations robustly maintained proliferation, osteogenic differentiation, and matrix remodeling capacities of MSCs and maintenance of HSPCs function over time. In vivo, scaffolds promoted strong and robust recruitment of hematopoietic cells to sites of ectopic transplantation, vascularization, and soft tissue formation.

Conclusions: Our tissue-engineered BM system is a powerful tool to explore the regulatory mechanisms of hematopoietic stem and progenitor cells for a better understanding of hematopoiesis in health and disease.
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http://dx.doi.org/10.1186/s13045-016-0234-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4727380PMC
January 2016

Telomere shortening in enterocytes of patients with uncontrolled acute intestinal graft-versus-host disease.

Blood 2015 Nov 20;126(22):2518-21. Epub 2015 Oct 20.

Department of Hematology, Oncology, Hemostaseology and Stem Cell Transplantation, Medical Faculty University Hospital Aachen, Rheinisch-Westfälische Technische Hochschule Aachen University, Aachen, Germany;

Acute intestinal graft-versus-host disease (aGVHD) refractory to immunosuppressive treatment is a serious complication after allogenic hematopoietic stem cell transplantation (HSCT). The underlying mechanisms of refractory aGVHD of the gut are not fully understood. Although telomere length (TL) reflects the replicative history of a cell, critically short telomeres have been associated with replicative exhaustion and tissue failure. In this study, we demonstrate that enterocytes of patients with refractory intestinal aGVHD show significantly increased proliferation, which translates into significant and critical telomere attrition following HSCT as compared with unaffected patients undergoing HSCT. Calculated telomere loss in aGVHD patients is 190 bp/wk, thereby massively exceeding physiological steady-state TL shortening rates such as in lymphocytes (∼50 bp/y). Our data support the hypothesis that increased compensatory proliferation following continued tissue damage can result in massive telomere loss in enterocytes of aGVHD patients. The present study introduces aGVHD-triggered increased cellular turnover and telomere loss with subsequent replicative exhaustion as a mechanism for refractory gut GVHD that is compatible with the long-term clinical aspect of the disease and provides a basis for stem cell protective therapies in the treatment of aGVHD.
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http://dx.doi.org/10.1182/blood-2015-03-633289DOI Listing
November 2015

Telomere dynamics in patients with del (5q) MDS before and under treatment with lenalidomide.

Leuk Res 2015 Sep 21. Epub 2015 Sep 21.

Department of Hematology, Oncology and Stem Cell Transplantation, Medical Faculty, RWTH Aachen University, Aachen, Germany.

Myelodysplastic syndrome (MDS) associated with an acquired, isolated deletion of chromosome 5q (del (5q) MDS), represent a clonal disorder of hematopoiesis and a clinically distinct entity of MDS. Treatment of del (5q) MDS with the drug lenalidomide has significantly improved quality of life leading to transfusion independence and complete cytogenetic response rates (CCR) in the majority of patients. Telomeres are located at the end of eukaryotic chromosomes and are linked to replicative history/potential as well as genetic (in) stability of hematopoietic stem cells. Here, we analyzed telomere length (TL) dynamics before and under lenalidomide treatment in the peripheral blood and/or bone marrow of del (5q) patients enrolled in the LEMON-5 study (NCT01081431). Hematopoietic cells from del (5q) MDS patients were characterized by significantly shortened TL compared to age-matched healthy controls. Telomere loss was more accelerated in patients with longer disease duration (>2 years) and more pronounced cytopenias. Sequential analysis under lenalidomide treatment revealed that previously shortened TL in peripheral blood cells was significantly "elongated" towards normal levels within the first six months suggesting a shift from clonal del (5q) cells towards normal hematopoiesis in lenalidomide treated MDS patients. Taken together our findings suggest that the development of the del (5q) clone is associated with accelerated telomere shortening at diagnosis. However, upon induction of CCR and reoccurrence of normal hematopoiesis, the lack of a persistent TL deficit argues against telomere-mediated genetic instability neither as a disease-promoting event of del (5q) MDS nor for lenalidomide mediated development of secondary primary malignancies of the hematopoietic system in responding patients.
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http://dx.doi.org/10.1016/j.leukres.2015.09.003DOI Listing
September 2015

Activation of IL-1β and TNFα genes is mediated by the establishment of permissive chromatin structures during monopoiesis.

Immunobiology 2013 Jun 26;218(6):860-8. Epub 2012 Oct 26.

Institute of Immunology, Medical Faculty, RWTH Aachen University, Aachen, Germany.

IL-1β and TNFα participate in a wide range of immunoregulatory activities. The overproduction of these cytokines can result in inflammatory and autoimmune diseases. Monocytes are the main producers of both cytokines. In contrast, studies with highly purified polymorphonuclear leukocytes (PMN) showed their inability to synthesize IL-1β and TNFα. Mature monocytes and PMN are derived from the same precursors. However, the reason for the differential IL-1β and TNFα expression is not elucidated. Our study investigates the epigenetic mechanisms that may explain this apparent discrepancy. The expression and promoter accessibilities of IL-1β and TNFα genes of primary and in vitro differentiated monocytes and PMN and their common precursors were compared. The effects of histone deacetylase (HDAC)-inhibition by trichostatin A (TSA) on IL-1β and TNFα expression and their promoter structures were measured in promyeloid HL-60 cells. Cytokine expression was assessed by real-time PCR and ELISA. Chromatin structures were analyzed using chromatin accessibility by real-time PCR (CHART) assay. The proximal IL-1β promoter was remodeled into an open conformation during monopoiesis, but not granulopoiesis. Although stimulation-dependent, remodeling of the TNFα promoter was again only observed in monocytes. TSA activated IL-1β and TNFα expression and supported chromatin remodeling of their promoters in HL-60 cells. The ability to express IL-1β and TNFα is linked to a cell type specific promoter structure, which is established during monocytic but not granulocytic differentiation. The participation of acetylation in IL-1β and TNFα promoter activation shed new light on the regulation of IL-1β or TNFα expression. These data may have implications for understanding the progression from normal to disease conditions.
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http://dx.doi.org/10.1016/j.imbio.2012.10.011DOI Listing
June 2013

Ex vivo expansion of cord blood-CD34(+) cells using IGFBP2 and Angptl-5 impairs short-term lymphoid repopulation in vivo.

J Tissue Eng Regen Med 2013 Dec 1;7(12):944-54. Epub 2012 Jun 1.

Institute of Pathology, RWTH Aachen University, Germany.

Cord blood-derived haematopoietic stem cells (CB-HSCs) are an attractive source for transplantation in haematopoietic disorders. However, the yield of CB-HSCs per graft is limited and often insufficient, particularly for the treatment of adult patients. Here we compare the capacity of three cytokine cocktails to expand CB-CD34(+) cells. Cells were cultured for 5 or 14 days in media supplemented with: (a) SCF, FL, IL-3 and IL-6 (SFLIL3/6); (b) SCF, TPO, FGF-1 and IL-6 (STFIL6); and (c) SCF, TPO, FGF-1, IGFBP2 and Angptl-5 (STFAI). We observed that STFAI-culture expansion sustained the most vigorous cell proliferation, maintenance of CD34(+) phenotype and colony-forming unit counts. In addition, STFAI-cultured cells had a potent ex vivo migration activity. STFAI-expanded cells were able to engraft NSG mice. However, no significant difference in overall engraftment was observed among the expansion cocktails. Assessment of short-term reconstitution using multilineage markers demonstrated that the STFAI cocktail for HSCs expansion greatly improved total cell expansion but may impair short-term lymphoid repopulation.
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http://dx.doi.org/10.1002/term.1486DOI Listing
December 2013

3D co-culture of hematopoietic stem and progenitor cells and mesenchymal stem cells in collagen scaffolds as a model of the hematopoietic niche.

Biomaterials 2012 Feb 1;33(6):1736-47. Epub 2011 Dec 1.

Institute of Pathology, RWTH Aachen University, Medical School, Pauwelsstrasse 30, 52074 Aachen, Germany.

Here, we propose a collagen-based three-dimensional (3D) environment for hematopoietic stem and progenitor cells (HPC) with mesenchymal stem cells (MSC) derived either from bone marrow (BM) or umbilical cord (UC), to recapitulate the main components of the BM niche. Mechanisms described for HPC homeostasis were systematically analyzed in comparison to the conventional liquid HPC culture. The 3D-cultivation allows dissecting two sub-populations of HPC: (I) HPC in suspension above the collagen gel and (II) migratory HPC in the collagen fibres of the collagen gel. The different sites represent distinct microenvironments with significant impact on HPC fate. HPC in niche I (suspension) are proliferative and a dynamic culture containing HPC (CD34(+)/CD38(-)), maturing myeloid cells (CD38(+), CD13(+), CAE(+)) and natural killer (NK) cells (CD56(+)). In contrast, HPC in niche II showed clonal growth with significant high levels of the primitive CD34(+)/CD38(-) phenotype with starting myeloid (CD13(+), CAE(+)) differentiation, resembling the endosteal part of the BM niche. In contrast, UC-MSC are not adequate for HSC expansion as they significantly enhance HPC proliferation and lineage commitment. In conclusion, the 3D-culture system using collagen and BM-MSC enables HPC expansion and provides a potential platform to dissect regulatory mechanisms in hematopoiesis.
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http://dx.doi.org/10.1016/j.biomaterials.2011.11.034DOI Listing
February 2012

Compatibility of different polymers for cord blood-derived hematopoietic progenitor cells.

J Mater Sci Mater Med 2012 Jan 10;23(1):109-16. Epub 2011 Nov 10.

Institute of Pathology, RWTH Aachen University, Aachen, Germany.

The low yield of hematopoietic progenitor cells (HPC) present in cord blood grafts limits their application in clinics. A reliable strategy for ex vivo expansion of functional HPC is a present goal in regenerative medicine. Here we evaluate the capacity of several two-dimensional polymers to support HPC proliferation. Basic compatibility was tested by measuring cell viability, cytotoxicity and apoptosis of CD34(+) progenitors that were short and long-term exposed to sixteen bio and synthetic polymers. Resomer(®) RG503, PCL and Fibrin might be good alternatives to tissue culture plastic for culture of CB-derived CD34(+) progenitors. Further, these polymers will be produced in three-dimensional structures and tested for their cytocompatibility.
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http://dx.doi.org/10.1007/s10856-011-4483-4DOI Listing
January 2012

Synergistic effects of growth factors and mesenchymal stromal cells for expansion of hematopoietic stem and progenitor cells.

Exp Hematol 2011 Jun 26;39(6):617-28. Epub 2011 Feb 26.

Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany.

Objective: The number of hematopoietic stem and progenitor cells (HPCs) per cord blood unit is limited, and this can result in delayed engraftment or graft failure. In vitro expansion of HPCs provides a perspective to overcome these limitations. Cytokines as well as mesenchymal stromal cells (MSCs) have been shown to support HPCs ex vivo expansion, but a systematic analysis of their interplay remains elusive.

Materials And Methods: Twenty different combinations of growth factors (stem cell factor [SCF], thrombopoietin [TPO], fibroblast growth factor-1 [FGF-1], angiopoietin-like 5, and insulin-like growth factor-binding protein 2), either with or without MSC coculture were systematically compared for their ability to support HPC expansion. CD34(+) cells were stained with carboxyfluorescein diacetate N-succinimidyl ester to monitor cell division history in conjunction with immunophenotype. Colony-forming unit frequencies and hematopoietic reconstitution of nonobese diabetic severe combined immunodeficient mice were also assessed.

Results: Proliferation of HPCs was stimulated by coculture with MSCs. This was further enhanced in combination with SCF, TPO, and FGF-1. Moreover, these conditions maintained expression of primitive surface markers for more than four cell divisions. Colony-forming unit-initiating cells were not expanded without stromal support, whereas an eightfold increase was reached by simultaneous cytokine-treatment and MSC coculture. Importantly, in comparison to expansion without stromal support, coculture with MSCs significantly enhanced hematopoietic chimerism in a murine transplantation model.

Conclusions: The supportive effect of MSCs on hematopoiesis can be significantly increased by addition of specific recombinant growth factors; especially in combination with SCF, TPO, and FGF-1.
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http://dx.doi.org/10.1016/j.exphem.2011.02.011DOI Listing
June 2011