Spinal and bulbar muscular atrophy (SBMA) is a motoneuronal diseases caused by an elogated polyglutamine (polyQ) tract in the androgen receptor (AR). The polyQ expansion causes the AR protein to misfold and the binding with the ligand testosterone triggers a cascade of events, including ARpolyQ aggregation, that led to motoneuron death. The intracellular accumulation of misfolded ARpolyQ both altered the protein quality control system (PQC) and impaired the protective mechanisms deputed to refolding and clearance of misfolded proteins. In PQC, the molecular chaperones allow the refolding or the clearance of the misfolded proteins through the Ubiquitin Proteasome system (UPS) or the autophagic pathway. Moreover, emerging evidence reveal that ARpolyQ toxicity is not related only to motoneuron degeneration but also skeletal muscle damage plays a primary role in SBMA. AIM: The aim of the study was both to unravell the contribution of PQC in SBMA and to find molecular and pharmacological approaches for modulating PQC as potential therapeutic target. Methods: Western blot and filter retardation assay were used to analyse the biochemical properties of ARpolyQ and the protein level of PQC markers. RT-qPCR was used to quantify the mRNA expression of PQC genes in presence of ARpolyQ. Results: In SBMA motoneuronal cell line, we demonstrated that both UPS and autophagic pathway are impaired or blocked, leading to ARpolyQ accumulation into the aggregates. Moreover, analysis in SBMA animal model showed that in the spinal cord and in the skeletal muscle, the PQC could differ considerably in how degrading the mutant and misfolded ARpolyQ. In these conditions of PQC impairment we tested, in SBMA cell model, the overexpression of the small heat shock protein B8 (HspB8), involved in the autophagic pathway. HpB8 led to the autophagic removal of misfolded ARpolyQ, restorating the intracellular autophagic flux. Interestingly, we found that trehalose, a known autophagic stimulator, was able to induce the HspB8 expression and to facilitate the ARpolyQ clearance. Then, we tested the combined treatment of trehalose with Bicalutamide, an antiandrogen. Bicalutamide is able to slow down AR nuclear translocation and to retain it into the cytoplasm, where the autophagic pathway is active. Bicalutamide and trehalose showed synergic activity in the degradation of ARpolyQ. Conclusions: the PQC plays a crucial role in SBMA, the modulation of its activity with trehalose and Bicalutamide might be a promising approach for this no cure disease.
The protein quality control system in motoneuron diseases / V. Crippa, M.E. Cicardi, M.J. Polanco, M. Meroni, R. Cristofani, M. Pennuto, M. Galbiati, A. Poletti. ((Intervento presentato al 16. convegno Congress for the Italian Society for Neuroscience tenutosi a Cagliari nel 2015.
|Titolo:||The protein quality control system in motoneuron diseases|
CICARDI, MARIA ELENA (Secondo)
GALBIATI, MARIARITA (Penultimo)
POLETTI, ANGELO (Ultimo)
|Data di pubblicazione:||9-ott-2015|
|Settore Scientifico Disciplinare:||Settore BIO/13 - Biologia Applicata|
|Enti collegati al convegno:||SOCIETA' ITALIANA DI NEUROSCIEZE|
|Citazione:||The protein quality control system in motoneuron diseases / V. Crippa, M.E. Cicardi, M.J. Polanco, M. Meroni, R. Cristofani, M. Pennuto, M. Galbiati, A. Poletti. ((Intervento presentato al 16. convegno Congress for the Italian Society for Neuroscience tenutosi a Cagliari nel 2015.|
|Appare nelle tipologie:||14 - Intervento a convegno non pubblicato|