The heat shock protein 70 co-chaperone ST13 - a candidate disease-modifying gene for Parkinson disease
Final Report Abstract
Parkinson’s disease (PD) is a neurodegenerative illness that affects five million people worldwide and no treatments are available to stop its relentless progression. The α- synuclein gene (aS), coding for small protein appears to be central to the pathogenesis of both rare familial and common sporadic forms of human PD. Importantly, aS toxicity in cellular, yeast, and fly models of PD can be suppressed by a molecular chaperone, heat shock protein 70 (HSP70). Recently, the host laboratory found that in the substantia nigra of patients with PD, expression of different HSP70 members like the co-chaperone ST13 is highly perturbed. This DFG project on the ST13 and its involvement in Parkinson’s disease was conducted at the hosting lab of Prof. Dr. Clemens Scherzer (Brigham & Women’s Hospital, Boston, USA). The scientific objectives of this were based on the hypothesis that “in common, sporadic PD reduced ST13 chaperone activity critically exacerbates αS aggregation and toxicity”. Two main aims were originally pursued: Firstly, analysis of ST13 modulation on αS aggregation and toxicity in cultured neuronal, dopaminergic cells. Secondly, delineation of changes in ST13 expression in brain and blood specimens of Parkinson disease patients compared to age- and sexmatched healthy and disease controls by kinetic, quantitative PCR and protein expression analyses. Aim one was to set up an appropriate cell model for studies of ST13 on alpha synulcein (aS). This was performed using neuronal, dopaminergic SH- SY5Y and 3D5 cells as a starting point to mimic a PD-like phenotype. Cellular toxicity and viability assays as well as fluorescence microcopy were used as a readout. Due to improper ST13 antibodies to detect ST13 overexpression fluorescence microscopy gave only insufficient results. Nevertheless, the 3D5 cell model showed very promising results in terms of inducible aS based toxicity to mimic PD like phenotypes. Aim two was pursued by quantifying ST13 expression changes in blood of PD patients. Initial studies showed that ST13 mRNA is reduced in PD patients as compared to healthy controls. Quantitative real time PCR was used to investigate the ST13 mRNA expression levels of one year follow- up samples to see whether ST13 could serve as a biomarker over progress of the disease. The follow- up study show that this decreased ST13 level was still persistent but more efforts are needed to validate ST13 as a proper biomarker for Parkinson’s disease.
Publications
- (2008). "RNA biomarkers of Parkinson'a disease: developing tools for novel therapies." Future Medicine 2(1): 41-53
Hennecke, G. and C. Scherzer
