Mitochondrial control of cell bioenergetics in Parkinson's disease

PMCID: PMC5065935Parkinson disease (PD) is a neurodegenerative disorder characterized by a selective loss of dopaminergic neurons in the substantia nigra. The earliest biochemical signs of the disease involve failure in mitochondrial-endoplasmic reticulum cross talk and lysosomal function, mitochondrial electron chain impairment, mitochondrial dynamics alterations, and calcium and iron homeostasis abnormalities. These changes are associated with increased mitochondrial reactive oxygen species (mROS) and energy deficiency. Recently, it has been reported that, as an attempt to compensate for the mitochondrial dysfunction, neurons invoke glycolysis as a low-efficient mode of energy production in models of PD. Here, we review how mitochondria orchestrate the maintenance of cellular energetic status in PD, with special focus on the switch from oxidative phosphorylation to glycolysis, as well as the implication of endoplasmic reticulum and lysosomes in the control of bioenergetics.J.P.B. is funded by the MINECO (SAF2013-41177-R; RTC-2015-3237-1), the ISCIII (RD12/0043/0021), the EU SP3-People-MC-ITN program (608381), the EU BATCure grant (666918), the NIH/NIDA (1R21DA037678-01).Peer Reviewe

Deficiency of Parkinson’s Related Protein DJ-1 Alters Cdk5 Signalling and Induces Neuronal Death by Aberrant Cell Cycle Re-entry

DJ-1 is a multifunctional protein involved in Parkinson disease (PD) that can act as antioxidant, molecular chaperone, protease, glyoxalase, and transcriptional regulator. However, the exact mechanism by which DJ-1 dysfunction contributes to development of Parkinson’s disease remains elusive. Here, using a comparative proteomic analysis between wild-type cortical neurons and neurons lacking DJ-1 (data available via ProteomeXchange, identifier PXD029351), we show that this protein is involved in cell cycle checkpoints disruption. We detect increased amount of p-tau and α-synuclein proteins, altered phosphoinositide-3-kinase/protein kinase B (PI3K/AKT) and mitogen-activated protein kinase (MAPK) signalling pathways, and deregulation of cyclin-dependent kinase 5 (Cdk5). Cdk5 is normally involved in dendritic growth, axon formation, and the establishment of synapses, but can also contribute to cell cycle progression in pathological conditions. In addition, we observed a decrease in proteasomal activity, probably due to tau phosphorylation that can also lead to activation of mitogenic signalling pathways. Taken together, our findings indicate, for the first time, that aborted cell cycle re-entry could be at the onset of DJ-1-associated PD. Therefore, new approaches targeting cell cycle re-entry can be envisaged to improve current therapeutic strategies

Loss of PRDX6 aborts proliferative and migratory signaling in hepatocarcinoma cell lines

Peroxiredoxin 6 (PRDX6), the only mammalian 1-Cys member of the peroxiredoxin family, has peroxidase, phospholipase A2 (PLA2), and lysophosphatidylcholine (LPC) acyltransferase (LPCAT) activities. It has been associated with tumor progression and cancer metastasis, but the mechanisms involved are not clear. We constructed an SNU475 hepatocarcinoma cell line knockout for PRDX6 to study the processes of migration and invasiveness in these mesenchymal cells. They showed lipid peroxidation but inhibition of the NRF2 transcriptional regulator, mitochondrial dysfunction, metabolic reprogramming, an altered cytoskeleton, down-regulation of PCNA, and a diminished growth rate. LPC regulatory action was inhibited, indicating that loss of both the peroxidase and PLA2 activities of PRDX6 are involved. Upstream regulators MYC, ATF4, HNF4A, and HNF4G were activated. Despite AKT activation and GSK3β inhibition, the prosurvival pathway and the SNAI1-induced EMT program were aborted in the absence of PRDX6, as indicated by diminished migration and invasiveness, down-regulation of bottom-line markers of the EMT program, MMP2, cytoskeletal proteins, and triggering of the “cadherin switch”. These changes point to a role for PRDX6 in tumor development and metastasis, so it can be considered a candidate for antitumoral therapies

Peroxiredoxin 6 Down-Regulation Induces Metabolic Remodeling and Cell Cycle Arrest in HepG2 Cells

Peroxiredoxin 6 (Prdx6) is the only member of 1-Cys subfamily of peroxiredoxins in human cells. It is the only Prdx acting on phospholipid hydroperoxides possessing two additional sites with phospholipase A2 (PLA2) and lysophosphatidylcholine-acyl transferase (LPCAT) activities. There are contrasting reports on the roles and mechanisms of multifunctional Prdx6 in several pathologies and on its sensitivity to, and influence on, the redox environment. We have down-regulated Prdx6 with specific siRNA in hepatoblastoma HepG2 cells to study its role in cell proliferation, redox homeostasis, and metabolic programming. Cell proliferation and cell number decreased while cell volume increased; import of glucose and nucleotide biosynthesis also diminished while polyamines, phospholipids, and most glycolipids increased. A proteomic quantitative analysis suggested changes in membrane arrangement and vesicle trafficking as well as redox changes in enzymes of carbon and glutathione metabolism, pentose-phosphate pathway, citrate cycle, fatty acid metabolism, biosynthesis of aminoacids, and Glycolysis/Gluconeogenesis. Specific redox changes in Hexokinase-2 (HK2), Prdx6, intracellular chloride ion channel-1 (CLIC1), PEP-carboxykinase-2 (PCK2), and 3-phosphoglycerate dehydrogenase (PHGDH) are compatible with the metabolic remodeling toward a predominant gluconeogenic flow from aminoacids with diversion at 3-phospohglycerate toward serine and other biosynthetic pathways thereon and with cell cycle arrest at G1/S transition

Integrated molecular signaling involving mitochondrial dysfunction and alteration of cell metabolism induced by tyrosine kinase inhibitors in cancer

Cancer cells have unlimited replicative potential, insensitivity to growth-inhibitory signals, evasion of apoptosis, cellular stress, and sustained angiogenesis, invasiveness and metastatic potential. Cancer cells adequately adapt cell metabolism and integrate several intracellular and redox signaling to promote cell survival in an inflammatory and hypoxic microenvironment in order to maintain/expand tumor phenotype. The administration of tyrosine kinase inhibitor (TKI) constitutes the recommended therapeutic strategy in different malignancies at advanced stages. There are important interrelationships between cell stress, redox status, mitochondrial function, metabolism and cellular signaling pathways leading to cell survival/death. The induction of apoptosis and cell cycle arrest widely related to the antitumoral properties of TKIs result from tightly controlled events involving different cellular compartments and signaling pathways. The aim of the present review is to update the most relevant studies dealing with the impact of TKI treatment on cell function. The induction of endoplasmic reticulum (ER) stress and Ca2+ disturbances, leading to alteration of mitochondrial function, redox status and phosphatidylinositol 3-kinase (PI3K)-protein kinase B (Akt)-mammalian target of rapamycin (mTOR) and AMP-activated protein kinase (AMPK) signaling pathways that involve cell metabolism reprogramming in cancer cells will be covered. Emphasis will be given to studies that identify key components of the integrated molecular pattern including receptor tyrosine kinase (RTK) downstream signaling, cell death and mitochondria-related events that appear to be involved in the resistance of cancer cells to TKI treatments.This study was funded by Institute of Health Carlos III (ISCiii) (PI16/00090, PI19/00838 and PI19/01266), Spanish Ministry of Economy and Competitiveness (BFU2016-80006-P), Andalusian Ministry of Economy, Innovation, Science and Employment (BIO-216 and CTS-6264), Andalusian Ministry of Equality, Health and Social Policies (PI-0198-2016) and Valencian Ministry of Education, Culture and Sports (PROMETEO/2019/027). P de la C-O was supported by FPU predoctoral fellowship (FPU17/00026) from Spanish Ministry of Education, Culture and Sports. E N-V was supported by the the predoctoral i-PFIS IIS-enterprise contract in science and technologies in health (IFI18/00014) from ISCiii. We thank the Biomedical Research Network Center for Cardiovascular Diseases (CIBERcv), and the Biomedical Research Network Center for Liver and Digestive Diseases (CIBERehd) founded by the ISCiii and co-financed by European Regional Development Fund (ERDF) "A way to achieve Europe" for their financial support

DJ1 represses glycolysis and cell proliferation by transcriptionally up-regulating pink1

PMCID: PMC4385472Using mouse embryonic fibroblasts (MEFs) from DJ1-knockout mice, in the present study, we show that DJ1, by binding with Foxo3a (forkhead box O3a), transcriptionally activates pink1 (phosphatase and tensin homologue deleted on chromosome 10-induced protein kinase-1) gene. Moreover, we demonstrate that, by promoting pink1 expression, DJ1 represses the rate of glycolysis and cell proliferation.This work was funded by the Spanish Ministerio de Economia y Competitividad [SAF2013-41177-R], the Instituto de Salud Carlos III [RD12/0043/0021], the SP3-People-MC-ITN programme of the European Commission [608381], the National Institutes of Drug Abuse/National Institutes of Health (NIH/NIDA) [1R21DA03767801], and the European Regional Development Fund to JPB. AAP was funded by the Instituto de Salud Carlos III [PI12/00685; RD12/0014/0007]. ILB is the recipient of a FPI Fellowship from the Spanish Ministerio de Economia y Competitividad (Spain).Peer Reviewe

Neuron-specific oxidative stress using a novel RNAi strategy in vivo causes cognitive impairment and carbonylation of key dendrite proteins

Resumen del póster presentado al XXXVI Congreso de la Sociedad Española de Bioquímica y Biología Molecular celebrado en Madrid del 3 al 6 de septiembre de 2013.Excess reactive oxygen species is behind the causes of neurological disorders, but the lack of tissue-specific experimental models of oxidative stress has complicated in vivo demonstration of proof-of-concept and mechanisms. Here, we designed and constructed a DNA vector with two unique restriction sites ready to insert any small hairpin RNA (shRNA) sequence in the opposite strand orientation, flanked by LoxP and Lox2272 sites, and governed by the polymerase III (H1) promoter. This DNA construct, after insertion of any shRNA, is suitable to trigger protein knockdown-mediated loss-of-function after tissue specific Cre-mediated recombination in vitro or in vivo. Using this strategy, we inserted a previously validated shRNA sequence targeted against glutamate-cysteine ligase catalytic subunit (GCL), the rate-limiting step in glutathione biosynthesis, into the above-mentioned DNA vector. With this shGCLfloxed DNA construct, we generated several transgenic mice founders, one of which harbored a unique insertion site and showed no apparent biochemical or phenotypic alterations. This shGCLfloxed mouse was crossed with mice harboring Cre recombinase governed by the neuron-specific CaMKIIα promoter (CaMKIIα-Cre), which is active after two postnatal weeks. The resulting CaMKIIα-shGCL mouse showed decreased GCL protein levels and increased signs of oxidative stress in hippocampal neurons during adulthood in vivo, as well as cognitive impairment. Oxy-proteome analysis of this region revealed a 3-fold increase in carbonylation of several proteins, of which at least one is involved in dendrite formation. To the best of our knowledge, this is the first evidence showing that neuron-specific oxidative stress in vivo oxidizes a key protein involved in memory formation leading to signs of dementia.Peer Reviewe

NOX1 and PRDX6 synergistically support migration and invasiveness of hepatocellular carcinoma cells through enhanced NADPH oxidase activity

The NADPH oxidase 1 (NOX1) complex formed by proteins NOX1, p22phox, NOXO1, NOXA1, and RAC1 plays an important role in the generation of superoxide and other reactive oxygen species (ROS) which are involved in normal and pathological cell functions due to their effects on diverse cell signaling pathways. Cell migration and invasiveness are at the origin of tumor metastasis during cancer progression which involves a process of cellular de-differentiation known as the epithelial-mesenchymal transition (EMT). During EMT cells lose their polarized epithelial phenotype and express mesenchymal marker proteins that enable cytoskeletal rearrangements promoting cell migration, expression and activation of matrix metalloproteinases (MMPs), tissue remodeling, and cell invasion during metastasis. In this work, we explored the importance of the peroxiredoxin 6 (PRDX6)-NOX1 enzyme interaction leading to NOXA1 protein stabilization and increased levels of superoxide produced by NOX in hepatocarcinoma cells. This increase was accompanied by higher levels of N-cadherin and MMP2, correlating with a greater capacity for cell migration and invasiveness of SNU475 hepatocarcinoma cells. The increase in superoxide and the associated downstream effects on cancer progression were suppressed when phospholipase A2 or peroxidase activities of PRDX6 were abolished by site-directed mutagenesis, reinforcing the importance of these catalytic activities in supporting NOX1-based superoxide generation. Overall, these results demonstrate a clear functional cooperation between NOX1 and PRDX6 catalytic activities which generate higher levels of ROS production, resulting in a more aggressive tumor phenotype

Pink1 deficiency sustains cell proliferation by reprogramming glucose metabolism through hif1

PTEN-induced kinase-1 (PINK1) is a Ser/Thr kinase implicated in familial early-onset Parkinson's disease, and was first reported as a growth suppressor. PINK1 loss-of-function compromises both mitochondrial autophagy and oxidative phosphorylation. Here we report that PINK1 deficiency triggers hypoxia-inducible factor-1α (HIF1α) stabilization in cultured Pink1-/- mouse embryonic fibroblasts and primary cortical neurons as well as in vivo. This effect, mediated by mitochondrial reactive oxygen species, led to the upregulation of the HIF1 target, pyruvate dehydrogenase kinase-1, which inhibits PDH activity. Furthermore, we show that HIF1a stimulates glycolysis in the absence of Pink1, and that the promotion of intracellular glucose metabolism by HIF1α stabilization is required for cell proliferation in Pink1 -/- mice. We propose that loss of Pink1 reprograms glucose metabolism through HIF1a, sustaining increased cell proliferation. © 2014 Macmillan Publishers Limited.This work was funded by the Spanish Ministerio de Economia y Competitividad (to J.P.B., grant number SAF2013-41177-R), the Instituto de Salud Carlos III (to J.P.B., grant number RD12/0043/0021; to A.A., grant numbers PI12/00685 and RD12/0014/0007), Junta de Castilla y Leon (to J.P.B., SA003U13), the SP3-People-MC-ITN programme of the European Commission (to J.P.B., 608381 TINTIN), and the European Regional Development Fund. I.L.-F. is the recipient of a FPI Fellowship from the MINECO (Spain).Peer Reviewe

Loss of PRDX6 Aborts Proliferative and Migratory Signaling in Hepatocarcinoma Cell Lines

Peroxiredoxin 6 (PRDX6), the only mammalian 1-Cys member of the peroxiredoxin family, has peroxidase, phospholipase A2 (PLA2), and lysophosphatidylcholine (LPC) acyltransferase (LPCAT) activities. It has been associated with tumor progression and cancer metastasis, but the mechanisms involved are not clear. We constructed an SNU475 hepatocarcinoma cell line knockout for PRDX6 to study the processes of migration and invasiveness in these mesenchymal cells. They showed lipid peroxidation but inhibition of the NRF2 transcriptional regulator, mitochondrial dysfunction, metabolic reprogramming, an altered cytoskeleton, down-regulation of PCNA, and a diminished growth rate. LPC regulatory action was inhibited, indicating that loss of both the peroxidase and PLA2 activities of PRDX6 are involved. Upstream regulators MYC, ATF4, HNF4A, and HNF4G were activated. Despite AKT activation and GSK3β inhibition, the prosurvival pathway and the SNAI1-induced EMT program were aborted in the absence of PRDX6, as indicated by diminished migration and invasiveness, down-regulation of bottom-line markers of the EMT program, MMP2, cytoskeletal proteins, and triggering of the “cadherin switch”. These changes point to a role for PRDX6 in tumor development and metastasis, so it can be considered a candidate for antitumoral therapies