scholarly journals Nuclear rupture at sites of high curvature compromises retention of DNA repair factors

2018 ◽  
Vol 217 (11) ◽  
pp. 3796-3808 ◽  
Author(s):  
Yuntao Xia ◽  
Irena L. Ivanovska ◽  
Kuangzheng Zhu ◽  
Lucas Smith ◽  
Jerome Irianto ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Dna Damage ◽  
Dna Repair ◽  
Opposite Effect ◽  
Cell Attachment ◽  
Collagen Fibers ◽  
Lamin A ◽  
Soft Matrix ◽  
Damage Marker ◽  
Nuclear Rupture

The nucleus is physically linked to the cytoskeleton, adhesions, and extracellular matrix—all of which sustain forces, but their relationships to DNA damage are obscure. We show that nuclear rupture with cytoplasmic mislocalization of multiple DNA repair factors correlates with high nuclear curvature imposed by an external probe or by cell attachment to either aligned collagen fibers or stiff matrix. Mislocalization is greatly enhanced by lamin A depletion, requires hours for nuclear reentry, and correlates with an increase in pan-nucleoplasmic foci of the DNA damage marker γH2AX. Excess DNA damage is rescued in ruptured nuclei by cooverexpression of multiple DNA repair factors as well as by soft matrix or inhibition of actomyosin tension. Increased contractility has the opposite effect, and stiff tumors with low lamin A indeed exhibit increased nuclear curvature, more frequent nuclear rupture, and excess DNA damage. Additional stresses likely play a role, but the data suggest high curvature promotes nuclear rupture, which compromises retention of DNA repair factors and favors sustained damage.

scholarly journals DNA damage in 3D constricted migration or after lamin-A depletion in 2D: shared mechanisms of repair factor mis-localization under nuclear stress

2016 ◽  
Author(s):  
Yuntao Xia ◽  
Jerome Irianto ◽  
Charlotte R. Pfeifer ◽  
Jiazheng Ji ◽  
Irena L. Ivanovska ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Nuclear Envelope ◽  
Nuclear Structure ◽  
Lamin A ◽  
Soft Matrix ◽  
Progeroid Syndromes ◽  
Standard Culture ◽  
Repair Factor ◽  
Insight Into

AbstractCells that migrate through small, rigid pores and that have normal levels of the nuclear structure protein lamin-A exhibit an increase in DNA damage, which is also observed with lamin-A depletion in diseases such as cancer and with many lamin-A mutations. Here we show nuclear envelope rupture is a shared feature that increases in standard culture after lamin-A knockdown, which causes nuclear loss of multiple DNA repair factors and increased DNA damage. Some repair factors are merely mis-localized to cytoplasm whereas others are partially depleted unless rescued by lamin-A expression. Compared to standard cultures on rigid glass coverslips, the growth of lamin-A low cells on soft matrix relaxes cytoskeletal stress on the nucleus, suppresses the mis-localization of DNA repair factors, and minimizes DNA damage nearly to wildtype levels. Conversely, constricted migration of the lamin-A low cells causes abnormally high levels of DNA damage, consistent with sustained loss of repair factors. The findings add insight into why monogenic progeroid syndromes that often associate with increased DNA damage and predominantly impact cells in stiff tissues result from mutations only in lamin-A or DNA repair factors.

scholarly journals Expression of progerin does not result in an increased mutation rate

2016 ◽  
Author(s):  
Emmanuelle Deniaud ◽  
Shelagh Boyle ◽  
Wendy Bickmore
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Dna Damage Response ◽  
Mutation Rate ◽  
Genetic Defect ◽  
Lamin A ◽  
Mutant Form ◽  
Premature Ageing ◽  
Damage Response ◽  
Per Se

AbstractIn the premature ageing disease Hutchinson-Gilford progeria syndrome (HGPS) the underlying genetic defect in the lamin A gene leads to accumulation at the nuclear lamina of progerin – a mutant form of lamin A that cannot be correctly processed. This has been reported to result in defects in the DNA damage response and in DNA repair, leading to the hypothesis that, as in normal ageing and in other progeroid syndromes caused by mutation of genes of the DNA repair and DNA damage response pathways, increased DNA damage may be responsible for the premature ageing phenotypes in HGPS patients. However, this hypothesis is based upon the study of markers of the DNA damage response, rather than measurement of DNA damage per se or the consequences of unrepaired DNA damage -mutation. Here, using a mutation reporter cell line, we directly compared the inherent and induced mutation rates in cells expressing wild-type lamin A or progerin. We find no evidence for an elevated mutation rate in progerin-expressing cells. We conclude that the cellular defect in HGPS cells does not lie in the repair of DNA damage per se.

scholarly journals DNA damage and repair in a model of rat vascular injury

2010 ◽  
Vol 118 (7) ◽  
pp. 473-485 ◽  
Author(s):  
Amalia Forte ◽  
Mauro Finicelli ◽  
Mario Grossi ◽  
Mariano Vicchio ◽  
Nicola Alessio ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Oxidative Dna Damage ◽  
Vascular Wall ◽  
Tissue Expression ◽  
Dna Damage And Repair ◽  
Reverse Transcription Pcr ◽  
Relevant Role ◽  
Temporary Decrease ◽  
Damage Marker

Restenosis rates following vascular interventions still limit their long-term success. Oxidative stress plays a relevant role in this pathophysiological phenomenon, but less attention has been devoted to its effects on DNA damage and to the subsequent mechanisms of repair. In the present study, we analysed in a model of arteriotomy-induced stenosis in rat carotid arteries the time-dependent expression of DNA damage markers and of DNA repair genes, together with the assessment of proliferation and apoptosis indexes. The expression of the oxidative DNA damage marker 7,8-dihydro-8-oxo-2′-deoxyguanosine was increased at 3 and 7 days after arteriotomy, with immunostaining distributed in the injured vascular wall and perivascular tissue. Expression of the DNA damage marker phospho-H2A.X was less relevant, but increased from 4 h to 7 days after arteriotomy, with immunostaining prevalently present in the adventitia and, to a lesser extent, in medial smooth muscle cells at the injury site. RT (reverse transcription)–PCR indicated a decrease in eight out of 12 genes involved in the DNA repair machinery we selected from 4 h to 7 days after arteriotomy, with the exception of an increase in the Mutyh and Slk genes (P<0.05). Western blot analysis revealed a decrease in p53 and catalase at 3 days after arteriotomy (P<0.05). A maximal 7% of BrdU-positive cells in the endothelium and media occurred at 7 days after arteriotomy, whereas the apoptotic index peaked at 3 days after injury (P<0.05). In conclusion, our results highlight a persistent DNA damage, presumably related to a temporary decrease in the expression of the DNA repair machinery and of the antioxidant enzyme catalase, playing a role in stenosis progression.

scholarly journals Mechanosensing by the lamina protects against nuclear rupture, DNA damage, and cell cycle arrest

2019 ◽  
Author(s):  
Sangkyun Cho ◽  
Manasvita Vashisth ◽  
Amal Abbas ◽  
Stephanie Majkut ◽  
Kenneth Vogel ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Arrest ◽  
Cell Types ◽  
Genome Integrity ◽  
Lamin A ◽  
Cycle Arrest ◽  
Nonmuscle Cell ◽  
Repair Factor ◽  
Nuclear Rupture

SummaryWhether cell forces or extracellular matrix (ECM) can impact genome integrity is largely unclear. Here, acute perturbations (~1hr) to actomyosin stress or ECM elasticity cause rapid and reversible changes in lamin-A, DNA damage, and cell cycle. Embryonic hearts, differentiated iPS-cells, and various nonmuscle cell types all show that actomyosin-driven nuclear rupture causes cytoplasmic mis-localization of DNA repair factors and excess DNA damage. Binucleation and micronuclei increase as telomeres shorten, which all favor cell cycle arrest. Deficiencies in lamin-A and repair factors exacerbate these effects, but lamin-A-associated defects are rescued by repair factor overexpression and by contractility modulators in clinical trials. Contractile cells on stiff ECM normally exhibit low phosphorylation and slow degradation of lamin-A by matrix-metalloprotease-2 (MMP2), and inhibition of this lamin-A turnover and also actomyosin contractility is seen to minimize DNA damage. Lamin-A is thus stress-stabilized to mechano-protect the genome.

scholarly journals Rescue of DNA damage after constricted migration reveals a mechano-regulated threshold for cell cycle

2019 ◽  
Vol 218 (8) ◽  
pp. 2545-2563 ◽  
Author(s):  
Yuntao Xia ◽  
Charlotte R. Pfeifer ◽  
Kuangzheng Zhu ◽  
Jerome Irianto ◽  
Dazhen Liu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Damage Threshold ◽  
Chromatin Binding ◽  
Lamin B ◽  
Cell Cycle Block ◽  
Break Formation ◽  
Damage Marker ◽  
Partial Effects ◽  
Nuclear Rupture

Migration through 3D constrictions can cause nuclear rupture and mislocalization of nuclear proteins, but damage to DNA remains uncertain, as does any effect on cell cycle. Here, myosin II inhibition rescues rupture and partially rescues the DNA damage marker γH2AX, but an apparent block in cell cycle appears unaffected. Co-overexpression of multiple DNA repair factors or antioxidant inhibition of break formation also exert partial effects, independently of rupture. Combined treatments completely rescue cell cycle suppression by DNA damage, revealing a sigmoidal dependence of cell cycle on excess DNA damage. Migration through custom-etched pores yields the same damage threshold, with ∼4-µm pores causing intermediate levels of both damage and cell cycle suppression. High curvature imposed rapidly by pores or probes or else by small micronuclei consistently associates nuclear rupture with dilution of stiff lamin-B filaments, loss of repair factors, and entry from cytoplasm of chromatin-binding cGAS (cyclic GMP-AMP synthase). The cell cycle block caused by constricted migration is nonetheless reversible, with a potential for DNA misrepair and genome variation.

scholarly journals Matrix Rigidity Myosin-II and Lamin-A Regulate Curvature Induced Nuclear Rupture Causing Repair Factor Mislocalization and DNA Damage

2018 ◽  
Vol 114 (3) ◽  
pp. 515a
Author(s):  
Yuntao Xia ◽  
Jerome Irianto ◽  
Kuangzheng Zhu ◽  
Cory Alvey ◽  
Lucas Smith ◽  
...  
Keyword(s):  
Dna Damage ◽  
Myosin Ii ◽  
Lamin A ◽  
Matrix Rigidity ◽  
Repair Factor ◽  
Nuclear Rupture

Naturally Produced Extracellular Matrix Is an Excellent Substrate for Canine Endothelial Cell Proliferation and Resistance to Shear Stress on PTFE Vascular Grafts

1997 ◽  
Vol 78 (05) ◽  
pp. 1392-1398 ◽  
Author(s):  
A Schneider ◽  
M Chandra ◽  
G Lazarovici ◽  
I Vlodavsky ◽  
G Merin ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Shear Stress ◽  
Endothelial Cell ◽  
Cell Attachment ◽  
Thrombus Formation ◽  
Endothelial Cell Proliferation ◽  
Ptfe Graft ◽  
Vascular Prostheses ◽  
Endothelial Cell Attachment

SummaryPurpose: Successful development of a vascular prosthesis lined with endothelial cells (EC) may depend on the ability of the attached cells to resist shear forces after implantation. The present study was designed to investigate EC detachment from extracellular matrix (ECM) precoated vascular prostheses, caused by shear stress in vitro and to test the performance of these grafts in vivo. Methods: Bovine aortic endothelial cells were seeded inside untreated polytetrafluoro-ethylene (PTFE) vascular graft (10 X 0.6 cm), PTFE graft precoated with fibronectin (FN), or PTFE precoated with FN and a naturally produced ECM (106 cells/graft). Sixteen hours after seeding the medium was replaced and unattached cells counted. The strength of endothelial cell attachment was evaluated by subjecting the grafts to a physiologic shear stress of 15 dynes/cm2 for 1 h. The detached cells were collected and quantitated. PTFE or EC preseeded ECM coated grafts were implanted in the common carotid arteries of dogs. Results: While little or no differences were found in the extent of endothelial cell attachment to the various grafts (79%, 87% and 94% of the cells attached to PTFE, FN precoated PTFE, or FN+ECM precoated PTFE, respectively), the number of cells retained after a shear stress was significanly increased on ECM coated PTFE (20%, 54% and 85% on PTFE, FN coated PTFE, and FN+ECM coated PTFE, respectively, p <0.01). Implantation experiments in dogs revealed a significant increase in EC coverage and a reduced incidence of thrombus formation on ECM coated grafts that were seeded with autologous saphenous vein endothelial cells prior to implantation. Conclusion: ECM coating significantly increased the strength of endothelial cell attachment to vascular prostheses subjected to shear stress. The presence of adhesive macromolecules and potent endothelial cell growth promoting factors may render the ECM a promising substrate for vascular prostheses.

Long-term efficacy of a new medical device containing Fernblock® and DNA repair enzyme complex in the treatment and prevention of cancerization field in patients with actinic keratosis.

2019 ◽  
Vol 2 (02) ◽  
pp. 80-89
Author(s):  
Blanca De Unamuno Bustos ◽  
Natalia Chaparr´´o Aguilera ◽  
Inmaculada Azorín García ◽  
Anaid Calle Andrino ◽  
Margarita Llavador Ros ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Medical Device ◽  
Actinic Keratosis ◽  
Statistical Significance ◽  
Dna Lesions ◽  
Enzyme Complex ◽  
Repair Enzyme ◽  
P53 Expression ◽  
Cancerization Field

Actinic keratosis (AKs) are part of the cancerization field, a region adjacent to AKs containing subclinical and histologically abnormal epidermal tissue due to Ultraviolet (UV)-induced DNA damage. The photoproducts as consequence of DNA damage induced by UV are mainly cyclobutane pyrimidine dimers (CPDs). Fernblock® demonstrated in previous studies significant reduction of the number of CPDs induced by UV radiation. Photolyases are a specific group of enzymes that remove the major UV-induced DNA lesions by a mechanism called photo-reactivation. A monocentric, prospective, controlled, and double blind interventional study was performed to evaluate the effect of a new medical device (NMD) containing a DNA-repair enzyme complex (photolyases, endonucleases and glycosilases), a combination of UV-filters, and Fernblock® in the treatment of the cancerization field in 30 AK patients after photodynamic therapy. Patients were randomized into two groups: patients receiving a standard sunscreen (SS) andpatients receiving the NMD. Clinical, dermoscopic, reflectance confocal microscopy (RCM) and histological evaluations were performed. An increase of AKs was noted in all groups after three months of PDT without significant differences between them (p=0.476). A significant increase in the number of AKs was observed in SS group after six (p=0.026) and twelve months of PDT (p=0.038); however, this increase did not reach statistical significance in the NMD group. Regarding RCM evaluation, honeycomb pattern assessment after twelve months of PDT showed significant differences in the extension and grade of the atypia in the NMD group compared to SS group (p=0.030 and p=0.026, respectively). Concerning histopathological evaluation, keratinocyte atypia grade improved from baseline to six months after PDT in all the groups, with no statistically significant differences between the groups. Twelve months after PDT, p53 expression was significantly lower in the NMD group compared to SS group (p=0.028). The product was well-tolerated, with no serious adverse events reported. Our results provide evidence of the utility of this NMD in the improvement of the cancerization field and in the prevention of the development of new AKs.  

Serum of 8-OHdG as a potential biomarker of oxidative DNA damage in workers exposed to harmful working environments

2020 ◽  
pp. 783-783
Author(s):  
I. A. Umnyagina ◽  
L. A. Strakhova ◽  
T. V. Blinova
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Blood Serum ◽  
Oxidative Dna Damage ◽  
Working Environment ◽  
Working Environments ◽  
Potential Biomarker ◽  
High Level ◽  
Damage Marker

In the blood serum of 70% individuals exposed to harmful factors of the working environment, a high level of oxidative stress and the DNA damage marker 8-Hydroxy-2’-Deoxyguanosine (8-OHdG) were detected.

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