Bir 2013 Abstract MiP2013

Bir A, Sen O, Anand S, Banerjee P, Sahoo A, Khemka V, Cappai R, Chakrabarti S (2013) α-Synuclein mediated alterations in mitochondrial oxidative phosphorylation system: Implications in the pathogenesis of Parkinson’s disease. Mitochondr Physiol Network 18.08.

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MiP2013, Book of Abstracts Open Access

Bir A, Sen O, Anand S, Banerjee P, Sahoo A, Khemka V, Cappai R, Chakrabarti S (2013)

Event: MiPNet18.08_MiP2013

α-Synucleinopathy and mitochondrial dysfunction are important elements of sporadic Parkinson’s disease (PD) pathogenesis [1]. It is, however, not clear whether the accumulated α-synuclein in degenerating dopaminergic neurons in PD causes mitochondrial injury and subsequent cell death. Our earlier study has shown that α-synuclein causes functional impairment of rat brain mitochondria incubated in vitro [2].

Mitochondrial membrane potential was measured using the carbocyanine dye JC1, and the phosphorylation capacity determined spectrophotometrically from inorganic phosphate utilization [2,3]. The respiratory functions of mitochondria in isolated preparations and within intact cells were analyzed by high-resolution respirometry. α-Synuclein accumulation within SHSY5Y cells was induced by lactacystin treatment and detected by immunoblotting. The transfection of SHSY5Y cells with α synuclein specific SiRNA was carried out using the lipofectamine kit (Invitrogen).

Our results show that α-synuclein causes a loss of membrane potential and phosphorylation capacity with alterations in respiratory parameters in isolated rat brain mitochondria. Some of these effects were inhibited very significantly by cyclosporine (1 μM). When SHSY5Y cells were exposed to 5 μM lactacystin for 24 h, α-synuclein accumulation occured intracellularly as detected by immunoblotting experiments. Further, lactacystin treatment of SHSY5Y cells also leads to mitochondrial dysfunction and cell death concomitant with α synuclein accumulation. To confirm the involvement of α synuclein in lactacystin induced mitochondrial dysfunction, the effects of cyclosporine and the gene silencing of α-synuclein with specific SiRNA on these phenomena are being investigated.

• O2k-Network Lab: IN Haldia Chakrabarti S

Labels: MiParea: Respiration, mt-Medicine  Pathology: Neurodegenerative, Parkinson's  Stress:Cell death  Organism: Rat  Tissue;cell: Nervous system, Other cell lines  Preparation: Intact cells, Isolated mitochondria 

Regulation: mt-Membrane potential  Coupling state: OXPHOS 

HRR: Oxygraph-2k 

SHSY5Y cells, MiP2013, S09 

Affiliations and author contributions

1 - Dept of Biochemistry, Institute of Postgraduate Medical Education and Research, Kolkata, India;

2 - Dept of Pathology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria, Australia.

Email: [email protected]

References

1. Beal MF (2004) Commentary on ‘‘Alpha-synuclein and mitochondria: a tangled skein”. Exp Neurol 186: 109–111.
2. Banerjee K, Sinha M, Pham Cle L, Jana S, Chanda D, Cappai R, Chakrabarti S (2010) Alpha-synuclein induced membrane depolarization and loss of phosphorylation capacity of isolated rat brain mitochondria: Implications in Parkinson’s disease. FEBS Lett 584: 1571-1576.
3. Bagh MB, Thakurta IG, Biswas M, Behera P, Chakrabarti S (2011) Age-related oxidative decline of mitochondrial functions in rat brain is prevented by long term oral antioxidant supplementation. Biogerontology 12: 119-131.