engleski

Hippocampal expression of neuroplastin in Alzheimer's disease

AIM The aim of this study was to analyze the expression of neuroplastin in human hippocampal tissue a"ected by Alzheimer’s neurodegeneration in comparison with age- and gender-matched controls. INTRODUCTION Neuroplastin, a cell surface glycoprotein found in two splice isoforms (np65, np55), is a member of immunoglobulin superfamily of cell adhesion molecules. Association of brain-specific neuroplastin isoform, np65, with developmental processes such as neuronal migration, neurite outgrowth and synaptogenesis has been found in rodent brain. Although distribution of np65 in adult human brain has been described, there are no data on np65 expression during aging and neurodegeneration. Alzheimer’s disease (AD) is characterized by up-regulated expression of plasticity molecules, particularly in hippocampus and entorhinal cortex, reflecting compensatory reorganization of remaining cellular structures. METHODS For that purpose, parafin-embedded sections of AD and control hippocampal tissue were analyzed by immunohistochemistry, using primary anti neuroplastin antibody. In addition, homogenates of hippocampal tissue samples are being used for Western blot analysis and RNA isolation, in order to determine neuroplastin expression at both transcriptomic and proteomic level. RESULTS Results on tissue distribution of neuroplastin immunoreactivity confirmed its extracellular localization in both control and AD hippocampal sections. The overall intensity of neuroplastin immunoreactivity was higher in AD than in control hippocampi, and was most notably expressed in neuronal population of dentate gyrus inner molecular layer. Interestingly, intracellular localisation of neuroplastin was detected in AD hippocampi, mostly in subiculum, which may indicate altered posttranslational modification and tra$cking of neuroplastin molecule. CONCLUSION We conclude that neuroplastin may serve as a plasticity marker and that detected increased expression of neuroplastin immunoreactivity in AD hippocampal tissue is related to neuronal remodelling and plasticity reactivation occurring in neurodegeneration.

neuroplastin; hippocampus; neurodegeneration

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