ATP13A2-mediated endo-lysosomal polyamine export counters mitochondrial oxidative stress

Area of Science:

• Neuroscience
• Cell Biology
• Genetics

Background:

• Recessive mutations in ATP13A2 (PARK9) cause neurodegenerative disorders like Parkinson's disease (PD).
• ATP13A2 transports polyamines, such as spermine, out of lysosomes.
• Dysfunction of ATP13A2 leads to polyamine buildup within lysosomes, causing cell damage.

Purpose of the Study:

• Investigate ATP13A2's protective role against mitochondrial toxins, specifically rotenone, a PD risk factor.
• Elucidate the mechanisms by which ATP13A2 mitigates rotenone-induced mitochondrial oxidative stress.

Main Methods:

• Utilized SH-SY5Y cells and patient-derived fibroblasts with ATP13A2 deficiency.
• Assessed mitochondrial reactive oxygen species (MitoROS) production and mitochondrial function.
• Employed rotenone, MitoTEMPO (antioxidant), and DFMO (synthesis inhibitor).
• Investigated cellular stress responses (ATF4-CHOP pathway).
• Validated findings in a C. elegans model deficient in the ATP13A2 ortholog (catp-6).

Main Results:

• ATP13A2 deficiency exacerbated rotenone-induced MitoROS, mitochondrial dysfunction, and cell death.
• Rotenone exposure in ATP13A2-deficient cells triggered an ATF4-CHOP stress response.
• MitoROS and stress responses were mitigated by MitoTEMPO and linked to spermine's antioxidant properties.
• ATP13A2's polyamine transport function was crucial for reducing rotenone/DFMO-induced MitoROS.
• Mitochondrial spermine uptake decreased with ATP13A2 deficiency.
• C. elegans lacking catp-6 showed elevated basal MitoROS, mitochondrial dysfunction, and rotenone hypersensitivity.

Conclusions:

• ATP13A2 plays a conserved role in protecting against mitochondrial oxidative stress.
• The protective mechanism involves ATP13A2-mediated lysosomal spermine export, which counters MitoROS.
• This pathway is vital for cellular defense against environmental toxins linked to neurodegeneration.