Biochemical and Biophysical Research Communications
SIRT3 deacetylated and increased citrate synthase activity in PD model
Introduction
Parkinson's disease (PD) is the second most common neurodegenerative disorder, as well as the most common movement disorder associated with the elderly [1]. PD, affects more than 1% of the population over the age of 65 years and more than 4% of the population by the age of 85 years [2]. So far there are no effective treatments or preventive therapies [3]. Therefore, it's of great importance to study the underlying mechanisms of dopaminergic (DA) neuronal degeneration and develop the relevant neuroprotective/therapeutic strategies. There are various factors involved in PD pathogenesis, of which mitochondrial dysfunction is the most remarkable one. It is generally accepted that DA neurons turn sensitive to mitochondrial dysfunction particularly in energy status. Neuronal damage has been closely connected with the reduction of intracellular adenosine triphosphate (ATP) level in the brain of PD patients, and in models of PD [4], [5]. Given that mitochondrial-based oxidative damage is a major postulated mechanism for PD pathogenesis [6], many investigators are focusing on mitochondrial enzymes.
Sirtuins, NAD+-dependent protein deacetylases, participates in systemic metabolic regulation, of which SIRT3, SIRT4, and SIRT5 are mitochondrial localized [3]. As the most principal one, SIRT3 is expected to participate in PD progression [3], but how it works still has been unknown. Recent findings suggest that SIRT3 deacetylates and activates mitochondrial enzymes, of which involved in fatty acid β-oxidation, amino acid metabolism, the electron transport chain, and antioxidant defenses [7].
Accumulating evidences have suggested that protein acetylation, as a major post-translational modification, is recognized as a major regulatory mechanism in mitochondrial function and neuronal health [8]. Our previous study found that MPP+ treatment decreased the expression of SIRT1 of DA neuron, which weakened the deacetylation to H3K14 and strengthened the combination of H3K14 with HIF1α promoter, and then increased the transcription activity of HIF1α [9].
Citrate synthase (CS), isocitrate dehydrogenase 2 (IDH2) and pyruvatede hydrogenase (PDH) are the gatekeeper enzymes of the citric acid cycle (TCA), which occur in the mitochondrial matrix and generate high-energy product for oxidative phosphorylation. Impaired CS activity could thus impact mitochondrial function and exacerbate age-related hearing loss [10]. Johnson et al. found that a missense mutation of CS is responsible for the ahl4-related hearing loss of A/J strain mice [10]. Other researchers found that PDH α1 subunit can be deacetylated by SIRT3 in vitro and in vivo, altering the activity of PDH as well as tumor cell metabolism [11]. Whether CS, IDH2 and PDH are participated in PD or associate with SIRT3 are unclear. The aim of this study is to examine the effects of SIRT3 on PD pathogenesis and uncover the molecular mechanisms involved.
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Cell culture and treatments
SH-SY5Y cells were maintained in Dulbecco's modified eagle's medium (DMEM) containing 10% heat-inactivated fetal bovine serum (GIBCO, Gaithersburg, MD, USA) and grown in a CO2 incubator maintained at atmospheric oxygen levels and 5% CO2. MPP+ (Sigma–Aldrich, St. Louis, MO, USA) stocks were dissolved in phosphate buffered saline (PBS) at a stock concentration at 125 mM which was stored at −20 °C. MPP+ was further diluted in serum free DMEM to achieve the final concentrations.
CCK8 cell viability assay
Cell viability was
MPP+ stimulated the proliferation inhibition, apoptosis, cell cycle arresting and mitochondrial dysfunction
MPP+ has been vastly used in all sorts of cell damage and PD cell models. In this study, to evaluate the neurotoxicity of MPP+ in SH-SY5Y cells, we examined the cell inhibition rate by CCK-8 method. We treated cells with MPP+ at various concentrations (0, 0.5, 1, 2.5, 5 mM)for 24 h. Compared to the control group, cells treated with MPP+ at a concentration of 2.5 mM achieved an approximate 50% increase in cell inhibition rate. So, the most suitable concentration is 2.5 mM. We used the indicated
Discussion
Sirtuins, including SIRT1-7, widely exists in various organisms from bacteria to humans [12]. SIRT1 is located in the nucleus, it regulates adaptive changes in gene expression in response to bioenergetic challenges [13]. While SIRT3 are mitochondrial localized, where it plays a critical role in regulating mitochondrial metabolic pathways [13]. Mitochondria are energy supply station of cells and contain many metabolic pathways. So the regulation of SIRT3 will affect not only the function of
Conflict of interest statement
The authors report no conflicts of interest with this study.
Acknowledgements
This work was supported by grants from the National Natural Science Foundation of China [grant numbers 81371410, 81171205], and the Biomedical Multidisciplinary Program of Shanghai Jiao Tong University [grant number YG2014MS31 to Yun-Cheng Wu], This work was supported by grant from Shanghai Natural Science Foundation (No. 16ZR1434000) to Te Liu.
References (25)
- et al.
Neuroprotection by Orexin-A via HIF-1alpha induction in a cellular model of Parkinson's disease
Neurosci Lett.
(2014) - et al.
Mitochondrial SIRT3 mediates adaptive responses of neurons to exercise and metabolic and excitatory challenges
Cell Metab.
(2016) - et al.
Mechanisms and dynamics of protein acetylation in mitochondria
Trends Biochem. Sci.
(2016) - et al.
The epigenetic regulation of HIF-1alpha by SIRT1 in MPP(+) treated SH-SY5Y cells
Biochem. Biophys. Res. Commun.
(2016) - et al.
Association of a citrate synthase missense mutation with age-related hearing loss in A/J mice
Neurobiol. Aging
(2012) - et al.
SIRT3 deacetylates and increases pyruvate dehydrogenase activity in cancer cells
Free Radic. Biol. Med.
(2014) - et al.
Mitochondrial SIRT3 mediates adaptive responses of neurons to exercise and metabolic and excitatory challenges
Cell Metab.
(2016) - et al.
Pituitary adenylate cyclase-activating polypeptide protects against beta-amyloid toxicity
Neurobiol. Aging
(2014) - et al.
Mutant SOD1(G93A) triggers mitochondrial fragmentation in spinal cord motor neurons: neuroprotection by SIRT3 and PGC-1 alpha
Neurobiol. Dis.
(2013) - et al.
SIRT3 protein deacetylates isocitrate dehydrogenase 2 (IDH2) and regulates mitochondrial redox status
J. Biol. Chem.
(2012)
Neuroprotection of deferoxamine on rotenone-induced injury via accumulation of HIF-1 alpha and induction of autophagy in SH-SY5Y cells
Neurochem. Int.
trans-(-)-ε-Viniferin increases mitochondrial sirtuin 3 (SIRT3), activates AMP-activated protein kinase (AMPK), and protects cells in models of Huntington Disease
J. Biol. Chem.
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