Mitochondrial damage modulates alternative splicing in neuronal cells: implications for neurodegeneration.
Mitochondrial damage is linked to many neurodegenerative conditions, such as Parkinson's disease, Alzheimer's disease and amyotrophic lateral sclerosis. These diseases are associated with changes in the splicing pattern of individual mRNAs. Here, we tested the hypothesis that mitochondrial damage modulates alternative splicing, not only of a few mRNAs, but in a general manner. We incubated cultured human neuroblastoma cells with the chemical agent paraquat (a neurotoxin that interferes with mitochondrial function, causing energy deficit and oxidative stress) and analysed the splicing pattern of 13 genes by RT-PCR. For all mRNAs that are alternatively spliced, we observed a dose- and time-dependent increase of the smaller isoforms. In contrast, splicing of all constitutive splicing exons that we monitored did not change. Using other drugs, we show that the modulation of alternative splicing correlates with ATP depletion, not with oxidative stress. Such drastic changes in alternative splicing are not observed in cell lines of non-neuronal origin, suggesting a selective susceptibility of neuronal cells to modulation of splicing. As a significant percentage of all mammalian mRNAs undergo alternative splicing, we predict that mitochondrial failure will unbalance a vast number of isoform equilibriums, which would give an important contribution to neurodegeneration.
Maracchioni
Alessia
A
Department of Experimental Neurosciences, European Centre for Brain Research, Fondazione Santa Lucia IRCCS, Rome, Italy.
Totaro
Antonio
A
Angelini
Daniela F
DF
Di Penta
Alessandra
A
Bernardi
Giorgio
G
Carrì
Maria Teresa
MT
Achsel
Tilmann
T
D000255:Adenosine Triphosphate / Q000378:metabolism; D017398:Alternative Splicing; D002460:Cell Line; D003513:Cycloheximide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D005910:Glioma; D006801:Humans; D008928:Mitochondria / Q000378:metabolism*; D009410:Nerve Degeneration / Q000139:chemically induced / Q000378:metabolism*; D009447:Neuroblastoma; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009498:Neurotoxins / Q000494:pharmacology; D010269:Paraquat / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013997:Time Factors
D009498:Neurotoxins; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D000255:Adenosine Triphosphate; D003513:Cycloheximide; D010269:Paraquat