Diaz-Casado 2014 Abstract SECF
| Melatonin restores mitochondrial regulatory gene expression and function
in the zebrafish model of parkinsonism.
Parkinson’s disease (PD) is a neurological disorder characterized by the progressive loss of dopaminergic (DA) neurons. Oxidative stress and inflammation are two key processes in the pathophysiology of PD. Both mechanisms are directly related to mitochondrial dysfunction and bioenergetic failure, which promotes neuronal death. The neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which specifically inhibits mitochondrial complex I activity, is usually used to yied parkinsonism in roedents and zebrafish. The association between mitochondrial dysfunction and neurodegeneration is gaining experimental support in PD, which can be associated with mutations in mitochondria-associated genes including DJ-1, alpha-synuclein, Park-2 and PINK-1. Because mitochondria are the main target of melatonin actions, we evaluated here whether its neuroprotective actions depend on the regulation of these genes in the zebrafish model of PD.
To generate a zebrafish model of PD with the use of MPTP, looking for molecular targets involved in the neuroprotective effects of melatonin.
Zebrafish embryos of the AB line were used at 24 hpf. 70 zebrafish embryos were randomly divided in three groups; Control Group (C); MPTP Group (MPTP), treated with MPTP (600 μM), and aMT Group (aMT), treated with MPTP (600 μM) and aMT (1μM) during 48h. Mitochondrial respiratory function and analysis of gene expression (qRT-PCR and Western Blot) of THase, Park-7, alpha-synuclein, Park-2, Park-6, and iNOS isoform were performed.
Assessment of complex I activity was 50% lower in 72 hpf embryos treated with 600 μM of MPTP compared to controls. In contrast, a significant increase in complex I activity was detected in embryos treated with MPTP plus aMT. RT-PCR and Western blot analysis suggested a significant decrease in the mRNA levels of 72 hpf embryos treated with MPTP (Park-7: -60%, THase: -55%, Park-2: - 45%, Park-6: -20% vs control) and in the proteins content (DJ: -32%, THase: -50%, Parkin:-65%, PINK-1: -45% vs control). Administration of aMT counteracted the expression of these genes. Likewise expression of alphasynuclein and iNOS increased in 72 hpf embryos treated with MPTP vs control; this rise was abrogated with the administration of aMT. A significant increase in proton leak was detected in MPTP group with a parallelly drop in coupling efficiency. Moreover, MPTP group showed a strong decline in maximum respiration rate. aMT treatment prevented these mitochondrial bioenergetic deficits.
These results suggest that 72 hpf embryos treated with MPTP showed a PD-like feature, consisting in a significant mitochondria and mitochondria-related genes impairment. These effects were antagonized by aMT treatment, supporting a functional role of aMT in controlling mitochondrial homeostasis even in the presence of a strong neurodegenerative process.
• Keywords: melatonin, parkinson, zebrafish.
• O2k-Network Lab: ES Granada Acuna-Castroviejo D
Labels: MiParea: Pharmacology;toxicology Pathology: Parkinson's Stress:Oxidative stress;RONS Organism: Zebrafish
1-Instituto de Biotecnología, Centro de Investigación Biomédica, Parque Tecnológico de Ciencias de la Salud, Universidad de Granada, Avda. Del Conocimiento s/n, 18100 Armilla, Granada, Spain. 2-Departamento de Fisiología, Facultad de Medicina,Universidad de Granada, Avenida de Madrid 11, 18012 Granada, Spain. 3-Unidad de Gestión Clínica de Laboratorios Clínicos, Hospital Universitario San Cecilio, Avenida Dr. Olóriz s/n, 18012 Granada, Spain.
Support by grant # PC-CTS-5784