title: Sustained accumulation of prelamin A and depletion of lamin A/C both cause oxidative stress and mitochondrial dysfunction but induce different cell fates.
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.
authors.affiliation: a Laboratory of Cell Biology and Histology; Department of Veterinary Sciences ; University of Antwerp ; Antwerp , Belgium.
authors.forename: Tom
authors.initials: T
authors.lastname: Sieprath
authors.forename: Tobias D J
authors.initials: TD
authors.lastname: Corne
authors.forename: Marco
authors.initials: M
authors.lastname: Nooteboom
authors.forename: Charlotte
authors.initials: C
authors.lastname: Grootaert
authors.forename: Andreja
authors.initials: A
authors.lastname: Rajkovic
authors.forename: Benjamin
authors.initials: B
authors.lastname: Buysschaert
authors.forename: Joke
authors.initials: J
authors.lastname: Robijns
authors.forename: Jos L V
authors.initials: JL
authors.lastname: Broers
authors.forename: Frans C S
authors.initials: FC
authors.lastname: Ramaekers
authors.forename: Werner J H
authors.initials: WJ
authors.lastname: Koopman
authors.forename: Peter H G M
authors.initials: PH
authors.lastname: Willems
authors.forename: Winnok H
authors.initials: WH
authors.lastname: De Vos
mesh_terms: D017209:Apoptosis; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D034904:Lamin Type A / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D053078:Membrane Potential, Mitochondrial; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism* / Q000473:pathology; D034881:Nuclear Lamina / Q000737:chemistry / Q000378:metabolism*; D018384:Oxidative Stress; D061251:Primary Cell Culture; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000819:agonists / Q000378:metabolism*; D015398:Signal Transduction; D013997:Time Factors
chemical_list: C494847:LMNA protein, human; D034904:Lamin Type A; D008565:Membrane Proteins; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; C090764:prelamin A; D008666:Metalloendopeptidases; C120130:ZMPSTE24 protein, human
keywords: 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