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Joudeh LA, DiCintio AJ, Ries MR, Gasperson AS, Griffin KE, Robbins VP, Bonner M, Nolan S, Black E, Waldman AS. Corruption of DNA end-joining in mammalian chromosomes by progerin expression. DNA Repair (Amst) 2023; 126:103491. [PMID: 37018982 PMCID: PMC10133198 DOI: 10.1016/j.dnarep.2023.103491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/23/2023] [Accepted: 03/29/2023] [Indexed: 04/03/2023]
Abstract
Hutchinson-Gilford Progeria Syndrome (HGPS) is a rare genetic condition characterized by features of accelerated aging and a life expectancy of about 14 years. HGPS is commonly caused by a point mutation in the LMNA gene which codes for lamin A, an essential component of the nuclear lamina. The HGPS mutation alters splicing of the LMNA transcript, leading to a truncated, farnesylated form of lamin A termed "progerin." Progerin is also produced in small amounts in healthy individuals by alternative splicing of RNA and has been implicated in normal aging. HGPS is associated with an accumulation of genomic DNA double-strand breaks (DSBs), suggesting alteration of DNA repair. DSB repair normally occurs by either homologous recombination (HR), an accurate, templated form of repair, or by nonhomologous end-joining (NHEJ), a non-templated rejoining of DNA ends that can be error-prone; however a good portion of NHEJ events occurs precisely with no alteration to joined sequences. Previously, we reported that over-expression of progerin correlated with increased NHEJ relative to HR. We now report on progerin's impact on the nature of DNA end-joining. We used a model system involving a DNA end-joining reporter substrate integrated into the genome of cultured thymidine kinase-deficient mouse fibroblasts. Some cells were engineered to express progerin. Two closely spaced DSBs were induced in the integrated substrate through expression of endonuclease I-SceI, and DSB repair events were recovered through selection for thymidine kinase function. DNA sequencing revealed that progerin expression correlated with a significant shift away from precise end-joining between the two I-SceI sites and toward imprecise end-joining. Additional experiments revealed that progerin did not reduce HR fidelity. Our work suggests that progerin suppresses interactions between complementary sequences at DNA termini, thereby shifting DSB repair toward low-fidelity DNA end-joining and perhaps contributing to accelerated and normal aging through compromised genome stability.
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Affiliation(s)
- Liza A Joudeh
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Alannah J DiCintio
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Madeline R Ries
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Andrew S Gasperson
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Kennedy E Griffin
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Victoria P Robbins
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Makenzie Bonner
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Sarah Nolan
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Emma Black
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Alan S Waldman
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.
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Komari CJ, Guttman AO, Carr SR, Trachtenberg TL, Orloff EA, Haas AV, Patrick AR, Chowdhary S, Waldman BC, Waldman AS. Alteration of genetic recombination and double-strand break repair in human cells by progerin expression. DNA Repair (Amst) 2020; 96:102975. [PMID: 33010688 DOI: 10.1016/j.dnarep.2020.102975] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/21/2020] [Accepted: 09/04/2020] [Indexed: 01/04/2023]
Abstract
Hutchinson-Gilford Progeria Syndrome (HGPS) is a rare autosomal, dominant genetic condition characterized by many features of accelerated aging. On average, children with HGPS live to about fourteen years of age. The syndrome is commonly caused by a point mutation in the LMNA gene which normally codes for lamin A and its splice variant lamin C, components of the nuclear lamina. The LMNA mutation alters splicing, leading to production of a truncated, farnesylated form of lamin A referred to as "progerin." Progerin is also expressed at very low levels in healthy individuals and appears to play a role in normal aging. HGPS is associated with an accumulation of genomic DNA double-strand breaks (DSBs), suggesting corruption of DNA repair. In this work, we investigated the influence of progerin expression on DSB repair in the human genome at the nucleotide level. We used a model system that involves a reporter DNA substrate inserted in the genome of cultured human cells. A DSB could be induced within the substrate through exogenous expression of endonuclease I-SceI, and DSB repair events occurring via either homologous recombination (HR) or nonhomologous end-joining (NHEJ) were recoverable. Additionally, spontaneous HR events were recoverable in the absence of artificial DSB induction. We compared DSB repair and spontaneous HR in cells overexpressing progerin versus cells expressing no progerin. We report that overexpression of progerin correlated with an increase in DSB repair via NHEJ relative to HR, as well as an increased fraction of HR events occurring via gene conversion. Progerin also engendered an apparent increase in spontaneous HR events, with a highly significant shift toward gene conversion events, and an increase in DNA amplification events. Such influences of progerin on DNA transactions may impact genome stability and contribute to aging.
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Affiliation(s)
- Celina J Komari
- Department of Public Health, University of South Carolina, Columbia, SC 29208, USA
| | - Anne O Guttman
- Department of Exercise Science, University of South Carolina, Columbia, SC 29208, USA
| | - Shelby R Carr
- Department of Exercise Science, University of South Carolina, Columbia, SC 29208, USA
| | - Taylor L Trachtenberg
- Department of Exercise Science, University of South Carolina, Columbia, SC 29208, USA
| | - Elise A Orloff
- Department of Exercise Science, University of South Carolina, Columbia, SC 29208, USA
| | - Ashley V Haas
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Andrew R Patrick
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Sona Chowdhary
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Barbara C Waldman
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Alan S Waldman
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.
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Brassard JA, Fekete N, Garnier A, Hoesli CA. Hutchinson-Gilford progeria syndrome as a model for vascular aging. Biogerontology 2015; 17:129-45. [PMID: 26330290 DOI: 10.1007/s10522-015-9602-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Accepted: 08/24/2015] [Indexed: 01/03/2023]
Abstract
Hutchinson-Gilford progeria syndrome (HGPS) is a premature aging disorder caused by a de novo genetic mutation that leads to the accumulation of a splicing isoform of lamin A termed progerin. Progerin expression alters the organization of the nuclear lamina and chromatin. The life expectancy of HGPS patients is severely reduced due to critical cardiovascular defects. Progerin also accumulates in an age-dependent manner in the vascular cells of adults that do not carry genetic mutations associated with HGPS. The molecular mechanisms that lead to vascular dysfunction in HGPS may therefore also play a role in vascular aging. The vascular phenotypic and molecular changes observed in HGPS are strikingly similar to those seen with age, including increased senescence, altered mechanotransduction and stem cell exhaustion. This article discusses the similarities and differences between age-dependent and HGPS-related vascular aging to highlight the relevance of HGPS as a model for vascular aging. Induced pluripotent stem cells derived from HGPS patients are suggested as an attractive model to study vascular aging in order to develop novel approaches to treat cardiovascular disease.
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Affiliation(s)
- Jonathan A Brassard
- Department of Chemical Engineering, McGill University, Wong Building, 3610 University Street, Montréal, QC, H3A 0C5, Canada.,Department of Chemical Engineering, Université Laval, 1065 Avenue de la Médecine, Québec, QC, G1V 0A6, Canada
| | - Natalie Fekete
- Department of Chemical Engineering, McGill University, Wong Building, 3610 University Street, Montréal, QC, H3A 0C5, Canada
| | - Alain Garnier
- Department of Chemical Engineering, Université Laval, 1065 Avenue de la Médecine, Québec, QC, G1V 0A6, Canada
| | - Corinne A Hoesli
- Department of Chemical Engineering, McGill University, Wong Building, 3610 University Street, Montréal, QC, H3A 0C5, Canada.
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Endisha H, Merrill-Schools J, Zhao M, Bristol M, Wang X, Kubben N, Elmore LW. Restoring SIRT6 Expression in Hutchinson-Gilford Progeria Syndrome Cells Impedes Premature Senescence and Formation of Dysmorphic Nuclei. Pathobiology 2015; 82:9-20. [PMID: 25765721 DOI: 10.1159/000368856] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 10/03/2014] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES Mice overexpressing SIRT6 live longer than wild-type mice while SIRT6 knockout mice exhibit similar degenerative phenotypes as individuals with Hutchinson-Gilford progeria syndrome (HGPS). Thus, we sought to test whether levels of SIRT6 are reduced in cells from individuals with HGPS and whether restored SIRT6 expression may impede premature aging phenotypes. METHODS Levels of endogenous SIRT6 and progerin in HGPS and normal fibroblasts were assessed by Western blotting and immunofluorescence. A tetracycline-inducible system was utilized to test whether progerin causes a rapid reduction in SIRT6 protein. SIRT6 was overexpressed in HGPS cells via lentiviral infection with biological endpoints including senescence-associated β-galactosidase (SA-β-gal) positivity, frequency of nuclear atypia, the number of 53BP1-positive DNA damage foci and growth rates. RESULTS Typical HGPS fibroblasts express lower levels of SIRT6 than fibroblasts from normal and atypical HGPS donors. Experimental induction of progerin did not cause a detectable reduction of SIRT6 protein. However, overexpression of SIRT6 in HGPS cells was associated with a reduced frequency of SA-β-gal positivity, fewer misshapen nuclei, fewer DNA damage foci, and increased growth rates. CONCLUSIONS Typical HGPS fibroblasts exhibit reduced levels of SIRT6 protein via a mechanism that remains to be elucidated. Our findings suggest that restoring SIRT6 expression in HGPS cells may partially impede senescence and the formation of dysmorphic nuclei. © 2015 S. Karger AG, Basel.
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Affiliation(s)
- Helal Endisha
- Department of Pathology, Virginia Commonwealth University, Richmond, Va., USA
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