Ganoderma lucidum Modulates Neuronal Distorted Cytoskeletal Proteomics and Protein-Protein Interaction in Alzheimer’s disease Model Animals

Abstract

Background: Alzheimer’s disease (AD) is the leading neurodegenerative disorder affecting memory, learning and behavior. Altered expression of proteins involved in neuronal structure and function is a recent observation of AD pathogenesis. Modulation of altered protein expression seems promising in AD therapeutics. In the present experiment, AD ameliorating effect of medicinal mushroom Ganoderma lucidum had been evaluated through its effect on neuronal cytoskeletal structure and function related protein expression pattern in AD model rats. Methods: Wistar male rats (120 ± 5gm) were divided into three groups: control (C), AD (A) and G. lucidum hot water extract (HWE) fed AD (AE), each group containing 15 rats. AD model rats were prepared by infusing Aβ1-42 (ab120959, abcam, USA) into the cerebral ventricles. Protein extraction from the brain samples was performed following homogenization of the hippocampus (50 mg ) with lysis buffer (1ml) using a homogenizer (Polytron PT 1200, Kinematica). Protein separation through SDS-PAGE and protein quantification through LC-chip MS/MS Q-TOF had been performed for label-free relative quantification. For statistical analyses, the data were exported to the Mass Profiler Professional (MPP) software and ANOVA (P<0.05) had been performed to overcome the complications of false discovery associated with multiple test analyses. Functional interaction networks of the proteins were identified using the STRING (Search Tool for the Retrieval of Interacting Genes/Proteins) database (version 10.0; http://string-db.org/). For further identifying over-representing pathways and biological functions, the ingenuity pathway analysis (IPA), build version: 389077M, content version: 27821452, (Release date: 2016-06-14) was used (https://www.ingenuity.com/wp-content/themes/ingenuity-qiagen). Datasets of the proteins significantly expressed (P<0.05) and having log fold change of 1.5 and higher were uploaded (AD versus C, AD versus AE and C versus AE). Results: Among 2,212 proteins identified in the present study, 819 had been found to be differentially expressed. Of the differentially expressed ones, 9 proteins had been linked with neuronal cytoskeletal structure and function regulation such as tubulin, β-actin, dihydropyrimidinase-related protein 2 (DRP-2), keratin, glial fibrillary acidic protein (GFAP), Rho A proteins, septin, cofilin, gelsolin and dynamin. AD rats manifested altered expression of proteins associated with neuronal structure and function. G. lucidum hot water treatment ameliorated the altered expression of those proteins. Conclusions: Altered expression of hippocampal proteins is a hallmark of AD. Neuroproteomics regulatory approach towards AD amelioration seems promising. Inclusion of G. lucidum for proteomics based AD therapeutics in regulation of the proteins involved in neuronal structure and function seem apt. Thus, G. lucidum could be considered as an AD therapeutic agent.