Epigenetic features in regulation of telomeres and telomerase in stem cells

2021 ◽  
Author(s):  
Fatma Dogan ◽  
Nicholas R. Forsyth
Keyword(s):  
Stem Cells ◽  
Telomere Length ◽  
Cell Biology ◽  
Replicative Senescence ◽  
Telomerase Activity ◽  
Cell Phenotype ◽  
Tissue Degeneration ◽  
Unique System ◽  
Telomerase Regulation

The epigenetic nature of telomeres is still controversial and different human cell lines might show diverse histone marks at telomeres. Epigenetic modifications regulate telomere length and telomerase activity that influence telomere structure and maintenance. Telomerase is responsible for telomere elongation and maintenance and is minimally composed of the catalytic protein component, telomerase reverse transcriptase (TERT) and template forming RNA component, telomerase RNA (TERC). TERT promoter mutations may underpin some telomerase activation but regulation of the gene is not completely understood due to the complex interplay of epigenetic, transcriptional, and posttranscriptional modifications. Pluripotent stem cells (PSCs) can maintain an indefinite, immortal, proliferation potential through their endogenous telomerase activity, maintenance of telomere length, and a bypass of replicative senescence in vitro. Differentiation of PSCs results in silencing of the TERT gene and an overall reversion to a mortal, somatic cell phenotype. The precise mechanisms for this controlled transcriptional silencing are complex. Promoter methylation has been suggested to be associated with epigenetic control of telomerase regulation which presents an important prospect for understanding cancer and stem cell biology. Control of down-regulation of telomerase during differentiation of PSCs provides a convenient model for the study of its endogenous regulation. Telomerase reactivation has the potential to reverse tissue degeneration, drive repair, and form a component of future tissue engineering strategies. Taken together it becomes clear that PSCs provide a unique system to understand telomerase regulation fully and drive this knowledge forward into aging and therapeutic application.

scholarly journals A feedback-loop between telomerase activity and stemness factors regulates PDAC stem cells

2020 ◽  
Author(s):  
Karolin Walter ◽  
Eva Rodriguez-Aznar ◽  
Monica S. Ventura Ferreira ◽  
Pierre-Olivier Frappart ◽  
Tabea Dittrich ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Biology ◽  
Feedback Loop ◽  
Telomerase Activity ◽  
Ductal Adenocarcinoma ◽  
Pancreatic Cancer Cells ◽  
Telomerase Regulation

AbstractTo date, it is still unclear how cancer stem cells (CSCs) regulate their stemness properties, and to what extent they share common features with normal stem cells. Telomerase regulation is a key factor in stem cell maintenance. In this study, we investigate how telomerase regulation affects cancer stem cell biology in pancreatic ductal adenocarcinoma (PDAC), and delineate the mechanisms by which telomerase activity and CSC properties are linked. Using primary patient-derived pancreatic cancer cells, we show that CSCs have higher telomerase activity and longer telomeres than bulk tumor cells. Inhibition of telomerase activity, using genetic TERT-knockdown or pharmacological inhibitor (BIBR1532) resulted in CSC marker depletion in vitro, and reduced tumorigenicity in vivo. Furthermore, we identify a positive feedback loop between stemness factors (KLF4, SOX2, OCT3/4, NANOG) and telomerase, which is essential for the self-renewal of pancreatic CSCs. Disruption the balance between telomerase activity and stemness factors, eliminates CSCs via induction of DNA damage and apoptosis, opening future perspectives to avoid CSC driven therapy resistance and tumor relapse in PDAC patients.

scholarly journals Telomere Length, Telomerase Activity, and Replicative Potential in HIV Infection: Analysis of CD4+ and CD8+T Cells from HIV-discordant Monozygotic Twins

1997 ◽  
Vol 185 (7) ◽  
pp. 1381-1386 ◽  
Author(s):  
Larry D. Palmer ◽  
Nan-ping Weng ◽  
Bruce L. Levine ◽  
Carl H. June ◽  
H. Clifford Lane ◽  
...  
Keyword(s):  
T Cells ◽  
Hiv Infection ◽  
Telomere Length ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Replicative Senescence ◽  
Monozygotic Twins ◽  
Telomerase Activity ◽  
Replicative Capacity

To address the possible role of replicative senescence in human immunodeficiency virus (HIV) infection, telomere length, telomerase activity, and in vitro replicative capacity were assessed in peripheral blood T cells from HIV+ and HIV− donors. Genetic and age-specific effects on these parameters were controlled by studying HIV-discordant pairs of monozygotic twins. Telomere terminal restriction fragment (TRF) lengths from CD4+ T cells of HIV+ donors were significantly greater than those from HIV− twins. In contrast, telomere lengths in CD8+ T cells from HIV+ donors were shorter than in HIV− donors. The in vitro replicative capacity of CD4+ cells from HIV+ donors was equivalent to that of HIV− donors in response to stimulation through T cell receptor CD3 and CD28. Little or no telomerase activity was detected in freshly isolated CD4+ or CD8+ lymphocytes from HIV+ or HIV− donors, but was induced by in vitro stimulation of both HIV+ and HIV− donor cells. These results suggest that HIV infection is associated with alterations in the population dynamics of both CD4+ and CD8+ T cells, but fail to provide evidence for clonal exhaustion or replicative senescence as a mechanism underlying the decline in CD4+ T cells of HIV-infected donors.

scholarly journals Imetelstat Inhibits Telomerase and Prevents Propagation of ADAR1-Activated Myeloproliferative Neoplasm and Leukemia Stem Cells

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 18-18
Author(s):  
Wenxue Ma ◽  
Larissa Balaian ◽  
Phoebe Mondala ◽  
Yudou He ◽  
Cayla Mason ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Stem Cell ◽  
Telomere Length ◽  
Mouse Models ◽  
Telomerase Activity ◽  
Rna Seq ◽  
Publicly Traded ◽  
Cd34 Cells

BACKGROUND Clonal stem cell derived myeloproliferative neoplasms (MPNs) have a propensity to evolve to acute myeloid leukemia (AML). Deregulation of the innate immune deaminase associated with RNA1 (ADAR1) has been linked to malignant progression and therapeutic resistance. Increased expression of the stem cell gene, human telomerase reverse transcriptase (hTERT), has also been linked with malignant transformation. However, the combinatorial role of ADAR1 and hTERT in the evolution of MPN stem cells to therapy resistant acute myeloid leukemia stem cells (LSCs) and the capacity of a telomerase inhibitor, imetelstat, to prevent survival and self-renewal of pre-LSC and LSC had not been established. Recent clinical trials show early signs of efficacy of imetelstat in treatment of myelofibrosis (MF). However, its role in selectively inhibiting pre-LSC transformation to self-renewing LSC has not been elucidated. Here we show that targeting telomerase activity prevents pre-LSC and LSC maintenance both in vitro and in vivo, suggesting telomerase inhibition as an effective strategy for preventing MPN progression. METHODS To quantify hTERT level and ADAR1 activity in the setting of normal HSPC and MPN stem cell evolution, whole genome sequencing (WGS) analysis was performed on 76 normal and MPN blood CD34+ cells and matching saliva samples. Results were compared with RNA-seq of 100 FACS purified young, aged, MPN and AML CD34+CD38- stem cells and CD34+CD38+ progenitor cells. Confocal fluorescence microscopic evaluation of stem cell ADAR1 and hTERT localization, telomere length by Flow-FISH and telomerase activity by TRAP assays, lentiviral ADAR1 overexpression and shRNA knockdown were performed. In vitro stromal co-cultures, and humanized immunocompromised mouse models were established to determine the impact of imetelstat (a oligonucleotide inhibitor of telomerase) on normal, MPN stem cell and LSC maintenance. RESULTS Combined hTERT overexpression, ADAR1 activation and a significant reduction in telomere length correlated with accelerated stem cell aging during MPN progression to AML. Increased ADAR1 mediated adenosine to inosine (A-to-I) transcript editing coincided with accelerated telomere shortening in high risk MPN stem cells. Moreover, lentiviral ADAR1 overexpression enhanced pre-LSC engraftment. Treatment with imetelstat reduced MPN stem cell and LSC propagation in stromal co-cultures as well as in humanized mouse models commensurate with reduced hTERT expression levels and telomerase activity and decreased ADAR1 editing activity. Specifically, stromal co-culture assays revealed that combined treatment with dasatinib at 1 nM, and imetelstat at 1 µM or 5 µM significantly inhibited survival and replating of blast crisis (BC) CML progenitors compared with aged bone marrow progenitors (p < 0.001, ANOVA). As a single agent, imetelstat (5 µM) inhibited survival and replating of pre-LSC derived from myelofibrosis compared with normal bone marrow progenitor samples (p < 0.001, ANOVA). In pre-LSC MPN NSG-SGM mouse models established from 4 different MF samples, a significant reduction in proliferation of human CD45+ cells (p < 0.01, t test) was observed in bone marrow and spleen, when compared with vehicle control. Treatment of humanized LSC mouse models, established with 5 different BC CML, with 30 mg/kg of imetelstat, 3 times a week for 4 weeks resulted in a significant reduction in proliferation of malignant progenitors and human CD45+ cells (p < 0.001, ANOVA). As measured by a Flow-FISH assay, abnormal telomere length was reversed by imetelstat treatment compared with mismatch control (p < 0.05, ANOVA). In addition, FACS analysis revealed a significant reduction in activated beta-catenin expression after imetelstat treatment of LSC engrafted mice compared with vehicle control (p < 0.01, ANOVA). Finally, RNA-seq analysis performed on human CD34+ cells from imetelstat treated LSC mouse models revealed a significant reduction in LSC harboring malignant ADAR1-mediated A-to-I editing at doses that spared normal hematopoietic stem cells. CONCLUSIONS Combined WGS and RNA-Seq analyses, lentiviral ADAR1 overexpression, stromal co-culture assays and humanized pre-LSC and LSC mouse model studies reveal that pre-LSC evolution into LSC coincides with both ADAR1 and hTERT activation, which can be prevented with imetelstat. Disclosures Rizo: Geron Corp: Current Employment, Current equity holder in publicly-traded company. Huang:Geron Corp: Current Employment, Current equity holder in publicly-traded company. Jamieson:Forty Seven Inc: Patents & Royalties; Bristol-Myers Squibb: Other.

Telomerase activity, mTert gene expression and the telomere length in mouse mesenchymal stem cells in the late period after γ- and γ,n-irradiation and in the tumors developed from these cells

2020 ◽  
Vol 66 (3) ◽  
pp. 265-273
Author(s):  
O.V. Vysotskaya ◽  
A.I. Glukhov ◽  
Yu.P. Semochkina ◽  
S.A. Gordeev ◽  
E.Yu. Moskaleva
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Bone Marrow ◽  
Mesenchymal Stem Cells ◽  
Telomere Length ◽  
Cell Lines ◽  
Telomerase Activity ◽  
Mouse Bone Marrow ◽  
Fibrosarcoma Cell

In proliferating normal and tumor cells, the telomere length (TL) is maintained by high telomerase activity (TA). In the absence of TA the TL maintenance involves a mechanism of alternative lengthening of telomeres (ALT). The aim of this study was to investigate the level of TA, the mTert expression and TL in cultured normal and transformed by γ- and γ,n-irradiation mesenchymal stem cells (MSCs) from mouse bone marrow, in sarcomas that developed after the transplantation of these cells into syngeneic mice, and in fibrosarcoma cell lines obtained from these tumors to find out the role of AT or ALT in maintaining TL in these cells. During prolonged cultivation of normal and transformed under the influence of γ- (1 Gy and 6 Gy) and γ,n-irradiation (0.05 Gy, 0.5 Gy, and 2 Gy) MSCs from mouse bone marrow, a decrease in TA was detected in irradiated cells. Even deeper decrease in TA was found in sarcomas developed after administration of transformed MSCs to syngeneic mice and in fibrosarcoma cell lines isolated from these tumors in which TA was either absent or was found to be at a very low level. TL in three of the four lines obtained was halved compared to the initial MSCs. With absent or low TA and reduced TL, the cells of all the obtained fibrosarcoma lines successfully proliferated without signs of a change in survival. The mechanism of telomere maintainance in fibrosarcoma cell lines in the absence of TA needs further investigation and it can be assumed that it is associated with the use of the ALT. The detected decrease or absence of TA in transformed under the action of irradiation MSCs with the preservation or even an increase in the telomerase gene expression may be associated with the formation of inactive splicing variants, and requires further study. The obtained lines of transformed MSCs and fibrosarcomas with TA and without the activity of this enzyme can be a useful model for studying the efficacy of TA and ALT inhibitors in vitro and in vivo.

scholarly journals Empty spiracles homeobox genes EMX1 and EMX2 regulate WNT pathway activation in sarcomagenesis

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Manuel Pedro Jimenez-García ◽  
Antonio Lucena-Cacace ◽  
Daniel Otero-Albiol ◽  
Amancio Carnero
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Transcription Factors ◽  
Cell Biology ◽  
Wnt Pathway ◽  
Ectopic Expression ◽  
Homeobox Genes ◽  
Cell Phenotype

Abstract Background Sarcomas are a very heterogeneous group of tumors with intrinsic developmental programs derived from the cell of origin. This implies a functional hierarchy inside tumors governed by sarcoma stem cells. Therefore, genetic and/or epigenetic changes profoundly affect the biology of sarcoma tumor stem cells. EMX genes are proposed to be transcription factors that are involved in the sarcomagenesis process, regardless of the neural or mesodermal embryological sarcoma origin. It has been shown that EMX1 or EMX2 overexpression reduces tumorigenic properties, while reducing the levels of these genes enhances these properties. Furthermore, it has been shown that EMX genes decrease the expression of stem cell regulatory genes and the stem cell phenotype. Taken together, these results indicate that the EMX1 and EMX2 genes negatively regulate these tumor-remodeling populations or sarcoma stem cells, acting as tumor suppressors in sarcoma. Methods Bioinformatic analysis, quantitative mRNA and protein expression analysis, cell models of sarcoma by ectopic expression of EMX genes. By cell biology methods we measured tumorigenesis and populations enriched on stem cell phenotypes, either in vitro or in vivo. Results In this work, we showed that the canonical Wnt pathway is one of the mechanisms that explains the relationships of EMX1/EMX2 and stem cell genes in sarcoma. The Wnt-EMX1/EMX2 relationship was validated in silico with sarcoma patient datasets, in vitro in primary derived sarcoma cell lines, and in vivo. EMX expression was found to negatively regulate the Wnt pathway. In addition, the constitutive activation of the Wnt pathway revers to a more aggressive phenotype with stem cell properties, and stemness gene transcription increased even in the presence of EMX1 and/or EMX2 overexpression, establishing the relationship among the Wnt pathway, stem cell genes and the EMX transcription factors. Conclusions Our data showed that Empty Spiracles Homeobox Genes EMX1 and EMX2 represses WNT signalling and activation of WNT pathway bypass EMX-dependent stemness repression and induces sarcomagenesis. These results also suggest the relevance of the Wnt/b-catenin/stemness axis as a therapeutic target in sarcoma.

scholarly journals Telomerase reverses epidermal hair follicle stem cell defects and loss of long-term survival associated with critically short telomeres

2007 ◽  
Vol 179 (2) ◽  
pp. 277-290 ◽  
Author(s):  
Irene Siegl-Cachedenier ◽  
Ignacio Flores ◽  
Peter Klatt ◽  
Maria A. Blasco
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Hair Follicle ◽  
Tissue Regeneration ◽  
Cell Biology ◽  
Premature Death ◽  
Telomerase Activity ◽  
Term Survival ◽  
Normal Life Span

Organ homeostasis and organismal survival are related to the ability of stem cells to sustain tissue regeneration. As a consequence of accelerated telomerase shortening, telomerase-deficient mice show defective tissue regeneration and premature death. This suggests a direct impact of telomere length and telomerase activity on stem cell biology. We recently found that short telomeres impair the ability of epidermal stem cells to mobilize out of the hair follicle (HF) niche, resulting in impaired skin and hair growth and in the suppression of epidermal stem cell proliferative capacity in vitro. Here, we demonstrate that telomerase reintroduction in mice with critically short telomeres is sufficient to correct epidermal HF stem cell defects. Additionally, telomerase reintroduction into these mice results in a normal life span by preventing degenerative pathologies in the absence of increased tumorigenesis.

312 ISOLATION, PROLIFERATION, AND CHARACTERIZATION OF MESENCHYMAL STEM CELLS FROM AMNIOTIC FLUID, AMNION, AND UMBILICAL CORD MATRIX IN THE DOG

2011 ◽  
Vol 23 (1) ◽  
pp. 252 ◽  
Author(s):  
L. Valentini ◽  
M. Filioli Uranio ◽  
A. Lange Consiglio ◽  
A. C. Guaricci ◽  
M. Caira ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Amniotic Fluid ◽  
Cell Viability ◽  
Umbilical Cord ◽  
Cell Biology ◽  
Cell Types ◽  
Telomerase Activity ◽  
Umbilical Cord Matrix

Mesenchymal stem cells (MSC) are defined as multipotent stem cells that can differentiate into various cell types in vivo and in vitro under controlled conditions. These cells express specific markers detectable by analysis at the mRNA or protein level. Important sources of MSC could be fetal adnexa, such as amniotic fluid (AF), amnion (AM), and umbilical cord matrix (UCM). Canine MSC should be of use for cell-based therapies and tissue engineering improving treatment of several diseases. Moreover, the dog has been considered an attractive animal model to study human diseases. In the present study, we successfully isolated and molecularly characterised AF-MSC, AM-MSC, and UCM-MSC from dogs. Chromosomal stability and telomerase activity were also investigated. Samples were recovered after elective ovariohysterectomy in 3 bitches 25 to 40 days of gestational age. After isolation, cells were maintained in culture (Bossolasco et al. 2006 Cell Res. 16, 329–336) for different passages to perform growth and doubling time (DT) studies. Expression analyses of embryonic (Oct-4, Nanog), mesenchymal (CD44, CD184, CD29), and haematopoietic (CD34, CD45) markers were carried out by RT-PCR. Karyotype analysis was performed by Q banding. Telomerase activity was analysed by TRAPeze Telomerase Detection Kit. In all 3 cell types, the morphology of proliferating cells appeared typically fibroblast-like. In the growth study, cells isolated from AF and AM were cultured until P3, and cells isolated from UCM were maintained until P7. The population DT in AF-MSC was significantly increased (Student’s t-test: P < 0.05) when comparing P1 v. P4. In AM-MSC, DT increased significantly in P1 v. P2 (P < 0.001), and in UCM-MSC, DT significantly increased in P1 v. P4 (P < 0.001). In AF-MSC, cell viability did not change with passages. In AM-MSC, cell viability significantly decreased (P < 0.001) between P1 and P4. In UCM-MSC, cell viability remained at approximately constant levels up to P6 and significantly decreased at P7 (P < 0.001). Amnion and UCM-MSC expressed Oct-4 and CD44, CD184, and CD29, whereas AF-MSC expressed only Oct-4 and CD44. Nanog, CD34, and CD45 were never found to be expressed in any cell line at any passage. In all cell lines, analysed metaphases at P4 showed normal chromosomal number and structure. Telomerase activity was observed in UCM-MSC, whereas tests on AF and AM-MSC are still on going. We first reported data on isolation, in vitro culture, and characterisation of MSC from AM and UCM in the dog. Cells expressed embryonic and MSC markers beginning at P1 and showed normal karyotype. These data indicated that canine MSC from fetal adnexa could be used to study stem cell biology and their application in therapeutic programs. Financial support was provided by Fondi di Ateneo 2009. University of Bari Aldo Moro (COD. ORBA09UDWX) (Resp. Sci. Maria Elena Dell’Aquila).

scholarly journals Establishing a deeper understanding of the osteogenic differentiation of monolayer cultured human pluripotent stem cells using novel and detailed analyses

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ping Zhou ◽  
Jia-Min Shi ◽  
Jing-E Song ◽  
Yu Han ◽  
Hong-Jiao Li ◽  
...  
Keyword(s):  
Stem Cells ◽  
Osteogenic Differentiation ◽  
Pluripotent Stem Cells ◽  
Embryonic Stem ◽  
Telomerase Activity ◽  
Human Pluripotent Stem Cells ◽  
Cell Counting ◽  
Cell Type ◽  
Alizarin Red

Abstract Background Derivation of osteoblast-like cells from human pluripotent stem cells (hPSCs) is a popular topic in bone tissue engineering. Although many improvements have been achieved, the low induction efficiency because of spontaneous differentiation hampers their applications. To solve this problem, a detailed understanding of the osteogenic differentiation process of hPSCs is urgently needed. Methods Monolayer cultured human embryonic stem cells and human-induced pluripotent stem cells were differentiated in commonly applied serum-containing osteogenic medium for 35 days. In addition to traditional assays such as cell viability detection, reverse transcription-polymerase chain reaction, immunofluorescence, and alizarin red staining, we also applied studies of cell counting, cell telomerase activity, and flow cytometry as essential indicators to analyse the cell type changes in each week. Results The population of differentiated cells was quite heterogeneous throughout the 35 days of induction. Then, cell telomerase activity and cell cycle analyses have value in evaluating the cell type and tumourigenicity of the obtained cells. Finally, a dynamic map was made to integrate the analysis of these results during osteogenic differentiation of hPSCs, and the cell types at defined stages were concluded. Conclusions Our results lay the foundation to improve the in vitro osteogenic differentiation efficiency of hPSCs by supplementing with functional compounds at the desired stage, and then establishing a stepwise induction system in the future.

scholarly journals The Cellular Senescence Stress Response in Post-Mitotic Brain Cells: Cell Survival at the Expense of Tissue Degeneration

Life ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 229
Author(s):  
Eric Sah ◽  
Sudarshan Krishnamurthy ◽  
Mohamed Y. Ahmidouch ◽  
Gregory J. Gillispie ◽  
Carol Milligan ◽  
...  
Keyword(s):  
Stress Response ◽  
Cell Fate ◽  
Cellular Senescence ◽  
Cell Biology ◽  
Brain Aging ◽  
Complex Stress ◽  
Brain Cell ◽  
Tissue Degeneration ◽  
Cellular Dna

In 1960, Rita Levi-Montalcini and Barbara Booker made an observation that transformed neuroscience: as neurons mature, they become apoptosis resistant. The following year Leonard Hayflick and Paul Moorhead described a stable replicative arrest of cells in vitro, termed “senescence”. For nearly 60 years, the cell biology fields of neuroscience and senescence ran in parallel, each separately defining phenotypes and uncovering molecular mediators to explain the 1960s observations of their founding mothers and fathers, respectively. During this time neuroscientists have consistently observed the remarkable ability of neurons to survive. Despite residing in environments of chronic inflammation and degeneration, as occurs in numerous neurodegenerative diseases, often times the neurons with highest levels of pathology resist death. Similarly, cellular senescence (hereon referred to simply as “senescence”) now is recognized as a complex stress response that culminates with a change in cell fate. Instead of reacting to cellular/DNA damage by proliferation or apoptosis, senescent cells survive in a stable cell cycle arrest. Senescent cells simultaneously contribute to chronic tissue degeneration by secreting deleterious molecules that negatively impact surrounding cells. These fields have finally collided. Neuroscientists have begun applying concepts of senescence to the brain, including post-mitotic cells. This initially presented conceptual challenges to senescence cell biologists. Nonetheless, efforts to understand senescence in the context of brain aging and neurodegenerative disease and injury emerged and are advancing the field. The present review uses pre-defined criteria to evaluate evidence for post-mitotic brain cell senescence. A closer interaction between neuro and senescent cell biologists has potential to advance both disciplines and explain fundamental questions that have plagued their fields for decades.

Assessment of Long-Term in vitro Multiplied Human Wharton’s Jelly-Derived Mesenchymal Stem Cells prior to Their Use in Clinical Administration

2021 ◽  
pp. 1-11
Author(s):  
Urvi Panwar ◽  
Kanchan Mishra ◽  
Parizad Patel ◽  
Sumit Bharadva ◽  
Salil Vaniawala ◽  
...  
Keyword(s):  
Telomere Length ◽  
Replicative Senescence ◽  
Ex Vivo ◽  
Wharton’S Jelly ◽  
Cellular Aging ◽  
Human Umbilical Cord ◽  
Surface Markers ◽  
Wharton's Jelly ◽  
Ex Vivo Culture

The quantity of mesenchymal stem/stromal cells (MSCs) required for a particular therapy demands their subsequent expansion through ex vivo culture. During in vitro multiplication, they undergo replicative senescence which may alter their genetic stability. Therefore, this study was aimed to analyze cellular, molecular, and chromosomal alterations in Wharton’s jelly-derived MSCs (WJ-MSCs) during their in vitro sequential passages, where WJ-MSCs were sequentially passaged up to P14 and cells were evaluated at an interval of P2, P6, P10, and P14. They were examined for their morphology, tumorigenicity, surface markers, stemness markers, DNA damage, chromosomal aberration, and telomere length. We have processed five full-term delivered human umbilical cord samples to obtain WJ-MSCs. Morphological appearance observed at initial stages was small fine spindle-shaped WJ-MSCs which were transformed to flat, long, and broader cells in later passages. The cell proliferation rate was gradually decreased after the 10th passage. WJ-MSCs have expressed stemness markers OCT-4 and NANOG, while they showed high expression of positive surface markers CD90 and CD105 and lower expression of CD34 and CD45. They were non-tumorigenic with slow cellular aging during subsequent passages. There was no chromosomal abnormality up to the 14th passage, while increase in comet score and decrease in telomere length were observed in later passages. Hence, our study suggests that early and middle passaged (less than P10) WJ-MSCs are good candidates for clinical administration for treatment.

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