The immunoexpression of LAMP2 protein in central nervous system in sporadic Creutzfeldt-Jakob disease (sCJD)
Piotr Gębski, Beata Sikorska
Introduction: Sporadic Creutzfeldt-Jakob disease (sCJD) is a fatal neurodegenerative disease. Based on the status of the codon 129 of the PRNP gene as well as the type of PrP Sc protein, sporadic CJD is divided into 6 subtypes. Each subtype possess both different histochemical phenotype and clinical manifestation. LAMP2 is a membrane protein limiting late endosomes and lysosomes, which acts as a key element in endosomal-lysosomal system (ELS). ELS plays an important role in all major protein degradation systems in eukaryotic cells. It has been recently suggested that disruptions in the function of protein degradation pathways are likely to be main events in almost all neurodegenerative diseases. The main aim for current work was to demonstrate immunoexpression of LAMP2 protein in subtypes of sCJD. Material and methods: The material for current study was 26 brain tissue samples collected from patients with sCJD. The immunoexpression of LAMP2 and PrP Sc proteins was studied by immunohistochemistry and confocal laser scanning microscopy (Olympus FluoView 1000). The studied group was subdivided into subgroups based on the subtype of sCJD. Semiquantitative results of the level of LAMP2 and PrP Sc immunoexpression were analysed using statistical methods. Correlation ratios between levels of immunoexpression of aforementioned proteins were assessed using the Pearson’s correlation test. Group differences in sCJD subtypes and age groups were assessed using ANOVA. Results: The studied group consisted of 7 cases of subtype 1, 9 cases of subtype 2, 2 cases of subtype 3 and 1 case of subtype 5 of sporadic CJD. Pearson’s correlation test showed statistically significant relationship between immunoexpression of LAMP2 and PrP Sc proteins. ANOVA showed significant differences between sCJD subtypes regarding immunoexpression of LAMP2 protein. No significant differences regarding immunoexpression of studied proteins were observed between age groups. Conclusions: 1) A strong positive correlation between levels of immunoexpressions of PrP Sc and LAMP2 may represent up-regulation of the protein processing by endosomal-lysosomal system. 2) Significant differences of immunoexpression of LAMP2 protein were observed between subtypes of sporadic CJD. 3) Confocal laser scanning microscopy results confirmed significant positive relationships between immunoexpression of PrP Sc and LAMP2 proteins.