Sustained accumulation of prelamin A and depletion of lamin A/C both cause oxidative stress and mitochondrial dysfunction but induce different cell fates.
Nucleus
; 6(3): 236-46, 2015.
Article
em En
| MEDLINE
| ID: mdl-25996284
ABSTRACT
The cell nucleus is structurally and functionally organized by lamins, intermediate filament proteins that form the nuclear lamina. Point mutations in genes that encode a specific subset of lamins, the A-type lamins, cause a spectrum of diseases termed laminopathies. Recent evidence points to a role for A-type lamins in intracellular redox homeostasis. To determine whether lamin A/C depletion and prelamin A accumulation differentially induce oxidative stress, we have performed a quantitative microscopy-based analysis of reactive oxygen species (ROS) levels and mitochondrial membrane potential (Δψm) in human fibroblasts subjected to sustained siRNA-mediated knockdown of LMNA and ZMPSTE24, respectively. We measured a highly significant increase in basal ROS levels and an even more prominent rise of induced ROS levels in lamin A/C depleted cells, eventually resulting in Δψm hyperpolarization and apoptosis. Depletion of ZMPSTE24 on the other hand, triggered a senescence pathway that was associated with moderately increased ROS levels and a transient Δψm depolarization. Both knockdowns were accompanied by an upregulation of several ROS detoxifying enzymes. Taken together, our data suggest that both persistent prelamin A accumulation and lamin A/C depletion elevate ROS levels, but to a different extent and with different effects on cell fate. This may contribute to the variety of disease phenotypes witnessed in laminopathies.
Palavras-chave
CM-H2DCFDA, 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate; HGPS, Hutchinson-Gilford progeria syndrome; LA, lamin A; LMNAkd, LMNA knockdown; MEF, mouse embryonic fibroblasts; NHDF, normal human dermal fibroblasts; NT, non-targeting; OCR, oxygen consumtion rate; PDL, population doubling level; PLA, prelamin A; RD, restrictive dermopathy; ROS, reactive oxygen species; TBHP, tert-butyl hydrogen peroxide; TMRM, tetramethyl rhodamine methyl ester; ZMPSTE24; ZMPSTE24kd, ZMPSTE24 knockdown; apoptosis; hMSCs, human mesenchymal stem cells; high-content microscopy; lamin A/C; laminopathies; mitochondria; mitochondrial dysfunction; oxidative stress; prelamin A; senescence; Δψm, mitochondrial membrane potential
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Espécies Reativas de Oxigênio
/
Lâmina Nuclear
/
Lamina Tipo A
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Fibroblastos
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Mitocôndrias
Limite:
Humans
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article