Details

Autor(en) / Beteiligte

• Albani, Diego
• Peverelli, Erika
• Rametta, Raffaela
• Batelli, Sara
• Veschini, Lorenzo
• Negro, Alessandro
• Forloni, Gianluigi

Titel

Protective effect of TAT‐delivered α‐synuclein: relevance of the C‐terminal domain and involvement of HSP70

Ist Teil von

• The FASEB journal, 2004-11, Vol.18 (14), p.1713-1715

Ort / Verlag

United States

Erscheinungsjahr

2004

Link zum Volltext

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• ABSTRACT α‐Synuclein (α‐syn) is a 140‐amino acid presinaptic protein whose mutations A30P and A53T have been linked to familiar Parkinson’s disease (PD). Many data suggest that α‐syn aggregation is the key event that triggers α‐syn‐mediated neurotoxicity. Nevertheless, other lines of evidence proposed a protective role of α‐syn against oxidative stress (a major feature of PD), even if the exact mechanism of this protective action and the role of the pathogenetic mutations to this respect have not been elucidated yet. To address these points, we developed an in vitro model of oxidative stress by exposing PC12 cells to hydrogen peroxide (H2O2) (150 µM) for 72 h, and we evaluated α‐syn‐mediated protection delivering increasing amounts of α‐syn (wild type [WT] or mutated) inside cells using the fusion proteins TAT‐α‐syn (WT, A30P, and A53T). We found that nanomolar amounts of TAT‐α‐syn‐mediated protected against oxidative stress and other cellular injuries (6‐hydroxydopamine and serum deprivation), whereas micromolar amounts of the fusion proteins were intrinsically toxic to cells. The protective effect was independent from the presence of the mutations A30P and A53T, but no protection occurred when cells were challenged with the proteasome inhibitors lactacystin and MG132. We verified that the protection mechanism required the presence of the C‐terminal domain of α‐syn, as nanomolar amounts of the C‐terminal truncated fusion protein TAT‐α‐syn (WT[1‐97]) failed in preventing H2O2 toxicity. To further characterize the molecular mechanisms at the basis of α‐syn protection, we investigated the possible involvement of the chaperone protein HSP70 that is widely implicated in neuroprotection. We found that, at nanomolar concentrations, TAT‐α‐syn was able to increase HSP70 protein level, whereas at the micromolar scale, TAT‐α‐syn decreased HSP70 at the protein level. These effects on HSP70 were independent from the presence of α‐syn pathogenetic mutations but required the α‐syn C‐terminal domain. The implications for α‐syn‐mediated neurotoxicity and for PD pathogenesis and progression are discussed.