FIGURE 2.

Mitochondrial dysfunction in aging and neurodegeneration. Mitochondrial dysfunction can have either a positive or a negative effect on the normal function of the cell; mild mitochondrial dysfunction stimulates retrograde signaling, increasing – among others – the production of antioxidant enzymes and inducing metabolic changes. This adaptive response leads to the extension of the lifespan of the organism. On the contrary, severe disturbance of the mitochondrial activity may become detrimental for the survival of the cell, as it compromises energy production, induces oxidative stress and disturbs calcium homeostasis. Under these conditions, neurons undergo rapid changes of the dendritic structures and, according to the damage, can engage detrimental programs that cause cell death. Thus, strong mitochondrial inefficiency may lead to the development of neurodegenerative diseases.