Search results for "telomere"

Determinants for Tight and Selective Binding of a Medicinal Dicarbene Gold(I) Complex to a Telomeric DNA G-Quadruplex: a Joint ESI MS and XRD Investi…

2016

International audience; The dicarbene gold(I) complex [Au(9-methylcaffein-8-ylidene)(2)]BF4 is an exceptional organometallic compound of profound interest as a prospective anticancer agent. This gold(I) complex was previously reported to be highly cytotoxic toward various cancer cell lines invitro and behaves as a selective G-quadruplex stabilizer. Interactions of the gold complex with various telomeric DNA models have been analyzed by a combined ESI MS and X-ray diffraction (XRD) approach. ESI MS measurements confirmed formation of stable adducts between the intact gold(I) complex and Tel 23 DNA sequence. The crystal structure of the adduct formed between [Au(9-methylcaffein-8-ylidene)(2)]…

Genetic and Environmental Effects on Telomere Length and Lung Function: A Twin Study.

2015

Background The purpose of the study was to estimate the heritability of leukocyte telomere length (LTL) and lung function and to examine whether LTL and lung function share genetic or environmental effects in common. Methods 386 monozygotic and dizygotic Finnish twin sisters (age 68.4±3.4 years) were included. Relative LTL was determined from peripheral blood DNA by qPCR. Lung function measures of FEV1, FVC, FEV1/FVC, and PEF were derived from spirometry. Genetic modeling was performed with MPlus statistical software. Results Univariate analysis revealed that in LTL, 62% (95% confidence interval 50-72) of the variance was explained by additive genetic and 38% (28-50) by unique environmental…

Role of the antioxidant defence system and telomerase in arsenic-induced genomic instability

2016

Arsenic (AS) is a reactive oxygen species (ROS)-inducer carcinogen, whose mode of action is still unclear. To defend against ROS, cells use enzymatic and non-enzymatic antioxidants, such as superoxide dismutase (SOD) and catalase. Failure of antioxidant systems (AXS) can result in dicentric chromosomes formation as well as telomere associations for the reduced activity of telomerase. In order to clarify the long-term effects of a past AS exposure, we evaluated the efficiency of the AXS and the telomerase activity in the progeny of arsenite-treated cells named ASO (arsenic shake-off) cells, previously obtained from arsenite-treated V79 cells and selected by shake-off. Despite SOD1 expression…

Telomeres and Telomerase During Human Papillomavirus-Induced Carcinogenesis

2018

Human papillomaviruses (HPVs) belong to a small spherical virus family and are transmitted through direct contact, most often through sexual behavior. More than 200 types of HPV are known, a dozen or so of which are classified as high-risk viruses (HR HPV) and may contribute to the development of cervical cancer. HPV is a small virus with a capsid composed of L1 and L2 proteins, which are crucial for entry to the cell. The infection begins at the basal cell layer and progresses to involve cells from higher layers of the cervical epithelium. E6 and E7 viral proteins are involved in the process of carcinogenesis. They interact with suppressors of oncogenesis, including p53 and Rb proteins. Th…

Acute depletion of telomerase components DKC1 and NOP10 induces oxidative stress and disrupts ribosomal biogenesis via NPM1 and activation of the P53…

2020

Mutations in DKC1, NOP10, and TINF2 genes, coding for proteins in telomerase and shelterin complexes, are responsible for diverse diseases known as telomeropathies and ribosomopathies, including dyskeratosis congenita (DC, ORPHA 1775). These genes contribute to the DC phenotype through mechanisms that are not completely understood. We previously demonstrated in models of DC that oxidative stress is an early and independent event that occurs prior to telomere shortening. To clarify the mechanisms that induce oxidative stress, we silenced genes DKC1, NOP10, and TINF2 with siRNA technology. With RNA array hybridisation, we found several altered pathways for each siRNA model. Afterwards, we ide…

The effect of long-term ultra-endurance exercise and SOD2 genotype on telomere shortening with age

2020

Telomere shortening, a well-known biomarker of aging, is a complex process influenced by several intrinsic and lifestyle factors. Although habitual exercise may promote telomere length maintenance, extreme endurance exercise has been also associated with increased oxidative stress—presumed to be the major cause of telomere shortening. Therefore, the pace of telomere shortening with age may also depend on antioxidant system efficiency, which is, in part, genetically determined. In this study, we aimed to evaluate the impact of ultra-endurance exercise and oxidative stress susceptibility (determined by the rs4880 polymorphism in the superoxide dismutase 2 (SOD2) gene) on telomere length. Geno…

Leukocyte and Skeletal Muscle Telomere Length and Body Composition in Monozygotic Twin Pairs Discordant for Long-term Hormone Replacement Therapy

2017

Estrogen-based hormone replacement therapy (HRT) may be associated with deceleration of cellular aging. We investigated whether long-term HRT has effects on leukocyte (LTL) or mean and minimum skeletal muscle telomere length (SMTL) in a design that controls for genotype and childhood environment. Associations between telomeres, body composition, and physical performance were also examined. Eleven monozygotic twin pairs (age 57.6 ± 1.8 years) discordant for HRT were studied. Mean duration of HRT use was 7.3 ± 3.7 years in the user sister, while their co-twins had never used HRT. LTL was measured by qPCR and SMTLs by southern blot. Body and muscle composition were estimated by bioimpedance an…

2020

Telomeres have the ability to adopt a lariat conformation and hence, engage in long and short distance intra-chromosome interactions. Budding yeast telomeres were proposed to fold back into subtelomeric regions, but a robust assay to quantitatively characterize this structure has been lacking. Therefore, it is not well understood how the interactions between telomeres and non-telomeric regions are established and regulated. We employ a telomere chromosome conformation capture (Telo-3C) approach to directly analyze telomere folding and its maintenance inS.cerevisiae. We identify the histone modifiers Sir2, Sin3 and Set2 as critical regulators for telomere folding, which suggests that a disti…

3D in Suspension versus 2D in Adhesion: molecular profiles in stemness and mesenchymal differentiation of Spheroids from Adipose-derived Stem Cells

2021

Purpose: Adipose stem cells (ASCs) represent a reliable source of stem cells with a widely demonstrated potential in regenerative medicine and tissue engineering applications. New recent insights suggest that three-dimensional (3D) models may closely mimic the native tissue properties; spheroids from adipose derived stem cells (S-ASCs) exhibit enhanced regenerative abilities compared with those of 2D models. Stem cell therapy success is determined by “cell-quality”; for this reason, microRNA profiles, the involvement of stress signals and cellular aging need to be further investigated. Material and Methods: Adipose tissue was collected from healthy individuals, 44 females and 17 males, afte…

A double-negative (IgD−CD27−) B cell population is increased in the peripheral blood of elderly people

2009

The T cell branch of the immune system has been extensively studied in the elderly and it is known that the elderly have impaired immune function, mainly due to the chronic antigenic load that ultimately causes shrinkage of the T cell repertoire and filling of the immunologic space with memory T cells. In the present paper, we describe the IgD(-)CD27(-) double-negative B cell population which (as we have recently described) is higher in the elderly. Most of these cells were IgG(+). Evaluation of the telomere length and expression of the ABCB1 transporter and anti-apoptotic molecule, Bcl2, shows that they have the markers of memory B cells. We also show that these cells do not act as antigen…