Techniques in gerontology: Cell lines as standards for telomere length and telomerase activity assessment

Fehrer, Christine; Voglauer, Regina; Wieser, Matthias; Pfister, Gerald; Brunauer, Regina; Cioca, Daniel; Grubeck‐Loebenstein, Beatrix; Lepperdinger, Günter

doi:10.1016/j.exger.2006.03.016

Cited by 24 publications

(22 citation statements)

References 18 publications

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“…Sixth, we determined the absolute telomere length of our calibrator to 5290 base pairs, which was comparable to previous reports for this cell line of 5360 and 6500 base pairs. 35,36 Limitations of the present study include that we examined risk of cardiovascular disease and early death in whites only, and our results may therefore not necessarily be applicable to other ethnicities. Also, we measured telomere length in leukocytes from peripheral blood only, and not in all cell types in the body; however, leukocyte telomere length is highly correlated with that in cells from other tissues.…”

Section: Weischer Et Almentioning

confidence: 95%

Short Telomere Length, Myocardial Infarction, Ischemic Heart Disease, and Early Death

Weischer

Bojesen

Cawthon

et al. 2012

ATVB

174

133

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Objective-We tested the hypothesis that short telomere length is associated with increased risk of myocardial infarction, ischemic heart disease, and early death. Methods and Results-We measured leukocyte telomere length in 2 prospective studies of 19 838 Danish general population participants from the Copenhagen City Heart Study and the Copenhagen General Population Study. Participants were followed for up to 19 years for incident myocardial infarction (nϭ929), ischemic heart disease (nϭ2038), and death (nϭ4342). Follow-up was 100% complete. Telomere length decreased linearly with increasing age in women and men in both studies (Pϭ7ϫ10 Ϫ74 to Pϭ3ϫ10 Ϫ125 ). Multifactorially adjusted hazard ratios were 1.10 (95% CI 1.01-1.19) for myocardial infarction, 1.06 (1.00 -1.11) for ischemic heart disease, and 1.09 (1.05-1.13) for early death per 1000 -base pair decrease in telomere length. The multifactorially adjusted hazard ratios for the shortest versus the longest decile of telomere length were 1.49 (1.07-2.07) for myocardial infarction, 1.24 (1.01-1.53) for ischemic heart disease, and 1.25 (1.07-1.46) for early death. Conclusion-Short telomere length is associated with only modestly increased risk of myocardial infarction, ischemic heart disease, and early death. Key Words: acute coronary syndromes Ⅲ ischemic heart disease Ⅲ death Ⅲ myocardial infarction Ⅲ telomere length T elomeres are protective chromosomal caps at the linear ends of chromosomes consisting of a variable number of TTAGGG repeats. 1 Telomeres shorten with each cell cycle in most cells and therefore reflect organism aging at a cellular level. 1,2 Accordingly, telomere length decreases with increasing age 3,4 but also with male sex, smoking, adiposity, oxidative stress, UV irradiation, and low socioeconomic status. 2,3,[5][6][7] It has therefore been a matter of speculation whether short telomere length is associated with increased risk of cardiovascular disease and early death. 5,8 -10 Previous studies of telomere length and human disease have been limited by cumbersome techniques mainly allowing low-throughput measurements. 11 Furthermore, the majority of studies so far have mainly been smaller case-control studies rather than large prospective studies of unselected individuals from the general population. 12 Accordingly, there is a need for large studies of the general population with extended follow-up, with telomere length measured reliably with a high-throughput method to examine the influence of short telomere length on cardiovascular disease and early death.We tested the hypothesis that short telomere length is associated with increased risk of myocardial infarction, ischemic heart disease, and early death. For this reason, we developed a high-throughput real-time polymerase chain reaction assay calibrated to measure absolute telomere length. Subsequently, we measured 19 838 individuals from 2 prospective studies of the Danish general population from the Copenhagen City Heart Study and the Copenhagen General Population Study, followed for u...

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Section: Weischer Et Almentioning

confidence: 95%

Short Telomere Length, Myocardial Infarction, Ischemic Heart Disease, and Early Death

Weischer

Bojesen

Cawthon

et al. 2012

ATVB

174

133

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“…Telomere length determination. Telomere length was determined in MDM by a qPCR as described in detail previously (15,26). In brief, telomere repeat copy numbers (T) and a single-copy gene (S; gene 36B4) were amplified using the following primers: for telomere amplifications, Tel1b (5=-CGGTTTGTTTGGGTTTGGGTTTGGGTTTGGGTTTGGGTT-3=) and tel2b (5=-GGCTTGCCTTACCCTTACCCTTACCCTTACCCTTAC CCT-3=); for single-copy gene amplifications, 36B4-sense (5=-CAGCAA GTGGGAAGGTGTAATCC-3=) and 36B4-antisense (5=-CCCATTCTAT CATCAACGGGTACAA-3=).…”

Section: Methodsmentioning

confidence: 99%

HIV-1 Induces Telomerase Activity in Monocyte-Derived Macrophages, Possibly Safeguarding One of Its Reservoirs

Reynoso

Wieser

Ojeda

et al. 2012

J Virol

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Monocyte-derived macrophages (MDM) are widely distributed in all tissues and organs, including the central nervous system, where they represent the main part of HIV-infected cells. In contrast to activated CD4 + T lymphocytes, MDM are resistant to cytopathic effects and survive HIV infection for a long period of time. The molecular mechanisms of how HIV is able to persist in macrophages are not fully elucidated yet. In this context, we have studied the effect of in vitro HIV-1 infection on telomerase activity (TA), telomere length, and DNA damage. Infection resulted in a significant induction of TA. This increase was directly proportional to the efficacy of HIV infection and was found in both nuclear and cytoplasmic extracts, while neither UV light-inactivated HIV nor exogenous addition of the viral protein Tat or gp120 affected TA. Furthermore, TA was not modified during monocyte-macrophage differentiation, MDM activation, or infection with vaccinia virus. HIV infection did not affect telomere length. However, HIV-infected MDM showed less DNA damage after oxidative stress than noninfected MDM, and this resistance was also increased by overexpressing telomerase alone. Taken together, our results suggest that HIV induces TA in MDM and that this induction might contribute to cellular protection against oxidative stress, which could be considered a viral strategy to make macrophages better suited as longer-lived, more resistant viral reservoirs. In the light of the clinical development of telomerase inhibitors as anticancer therapeutics, inhibition of TA in HIV-infected macrophages might also represent a novel therapeutic target against viral reservoirs.

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“…20,21 The single-copy gene 36B4 was used as a housekeeping gene (S). Telomere length of each sample was expressed as the relative T/S ratio after being standardized to the single-copy gene of the same sample as well as the mean T/S ratio for all samples on the same plate reflecting the well-to-well variation.…”

Section: Telomere Measurement By Real-time Quantitative Pcrmentioning

confidence: 99%

“…In addition, the average telomere length of HIV-1-specific CD8 ϩ T cells from individuals with chronic progressive infection was significantly lower compared with the corresponding bulk CD8 ϩ T cells sorted from the same study population (P ϭ .009), while the telomeres of HIV-1-specific CD8 ϩ T cells from controllers were significantly longer than those from the respective bulk CD8 ϩ T cells isolated from that study cohort (P ϭ .004; Figure 1B). Using 2 cell lines (293T and K562) with known telomere lengths as references, 21 we calculated the absolute telomere lengths of HIV-1-specific CD8 ϩ T cells from progressors to reach a median of 5.8 kb (range, 4.8-6.4 kb). In contrast, HIV-1-specific CD8 ϩ T cells from controllers has a median absolute telomere length of 7.4 kb (range, 6.3-12.9 kb; P Ͻ .001).…”

Section: Telomere Length Stabilization In Hiv-1-specific Cd8 ؉ T Cellmentioning

confidence: 99%

Telomerase activity of HIV-1–specific CD8+ T cells: constitutive up-regulation in controllers and selective increase by blockade of PD ligand 1 in progressors

Lichterfeld

Mou

Cung

et al. 2008

Blood

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Exhaustion of virus-specific T cells may play an important role in the pathophysiology of chronic viral infections. Here, we analyzed telomere length and telomerase activity in HIV-1-specific CD8 ؉ T cells from progressors or controllers to determine underlying molecular pathways of T-cell exhaustion and senescence. Telomere lengths of HIV-1-specific CD8 ؉ T cells from progressors were significantly shorter compared with autologous cytomegalovirus (CMV)/Epstein-Barr virus (EBV)-specific CD8 ؉ T cells or bulk CD8 ؉ T cells, while telomere lengths from controllers significantly exceeded those of autologous bulk CD8 ؉ T cells and reached a similar level as HIV-1-specific CD8 ؉ T cells collected during primary HIV-1 infection. Telomere length stabilization in controllers corresponded to high levels of constitutive telomerase activity, which was associated with preservation of cytotoxic and proliferative properties. Conversely, limited constitutive telomerase activity was observed in HIV-1-specific CD8 ؉ T cells from progressors, although an increase in both telomere length and telomerase activity was IntroductionSpontaneous control of HIV-1 viremia is achieved in a small proportion of infected individuals called HIV controllers. The relative overrepresentation of specific MHC class I alleles such as HLA-B57 and HLA-B27 in this specific patient population 1,2 suggests that low-level viremia in these persons is at least partially mediated by HIV-1-specific CD8 ϩ T cells. However, progressive viremia in advanced stages of infection typically occurs in the presence of strong, broadly diversified, and polyclonal HIV-1-specific CD8 ϩ T-cell populations [3][4][5] with preserved recognition of the autologous virus 6 and a similar immunodominance pattern as described in controllers. 7,8 This paradoxic finding has recently been related to a defective functional profile of HIV-1-specific CD8 ϩ T cells in chronic progressive infection, which have preserved IFN-␥ secretion, but lack ex vivo antigen-specific proliferative activities. In contrast, HIV-1-specific CD8 ϩ T cells collected from HIV-1 controllers were found to have strong ex vivo proliferative activities, which was associated with increased perforin expression and superior cytotoxic properties. 3 Although cellular exhaustion and accelerated immune senescence has been repeatedly suggested as key mechanisms in HIV immunopathogenesis, 9-13 aging of HIV-1-specific T cells as well as regulatory molecular processes governing their senescence have never been analyzed. Moreover, how alterations in immune senescence are involved in the development of HIV-1-specific T-cell dysfunction in progressive HIV-1 infection or in the maintenance of polyfunctional HIV-1-specific T cells in HIV controllers is currently unknown. In addition, it is currently unclear whether progressive senescence of HIV-1-specific T cells is an irreversible process, or whether aging of these cells can actively be manipulated for immunotherapeutic purposes.In the present study, we conducted a detailed analys...

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Techniques in gerontology: Cell lines as standards for telomere length and telomerase activity assessment

Cited by 24 publications

References 18 publications

Short Telomere Length, Myocardial Infarction, Ischemic Heart Disease, and Early Death

Short Telomere Length, Myocardial Infarction, Ischemic Heart Disease, and Early Death

HIV-1 Induces Telomerase Activity in Monocyte-Derived Macrophages, Possibly Safeguarding One of Its Reservoirs

Telomerase activity of HIV-1–specific CD8+ T cells: constitutive up-regulation in controllers and selective increase by blockade of PD ligand 1 in progressors

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