Changes in the Golgi Apparatus of Neocortical and Hippocampal Neurons in the Hibernating Hamster.

Alejandro Antón-Fernández,Gonzalo León-Espinosa,Alberto Muñoz,Javier Defelipe

doi:10.3389/fnana.2015.00157

Abstract

Hibernating animals have been used as models to study several aspects of the plastic changes that occur in the metabolism and physiology of neurons. These models are also of interest in the study of Alzheimer's disease because the microtubule-associated protein tau is hyperphosphorylated during the hibernation state known as torpor, similar to the pretangle stage of Alzheimer's disease. Hibernating animals undergo torpor periods with drops in body temperature and metabolic rate, and a virtual cessation of neural activity. These processes are accompanied by morphological and neurochemical changes in neurons, which reverse a few hours after coming out of the torpor state. Since tau has been implicated in the structural regulation of the neuronal Golgi apparatus (GA) we have used Western Blot and immunocytochemistry to analyze whether the GA is modified in cortical neurons of the Syrian hamster at different hibernation stages. The results show that, during the hibernation cycle, the GA undergo important structural changes along with differential modifications in expression levels and distribution patterns of Golgi structural proteins. These changes were accompanied by significant transitory reductions in the volume and surface area of the GA elements during torpor and arousal stages as compared with euthermic animals.

Highlights

The Golgi complex is a cellular organelle involved in the processing, modification, transport and targeting of cellular proteins
To characterize possible alterations during the hibernation cycle in the Golgi apparatus (GA) of neocortical and hippocampal neurons of Syrian hamsters, we first performed experiments with immunocytochemical staining using antibodies directed against GM130, MG160, and Golgin84 to study their distribution in euthermic hamsters (Figure 1)
It has been previously established that GM130 is mainly localized in the cis-Golgi compartment, MG160 is localized in the medial cisternae and golgin-84 is present throughout the Golgi stacks with an increasing gradient toward the transside

Summary

Introduction

The Golgi complex is a cellular organelle involved in the processing, modification, transport and targeting of cellular proteins It is composed of stacks comprising closely apposed flattened cisternae and vesicles usually localized in the juxtanuclear area (Képès et al, 2005; Egea et al, 2006; Yadav and Linstedt, 2011) and held in position due to microtubule (MT)-dependent mechanisms. In mammalian cells, these stacks are laterally linked to form a membrane network, termed the Golgi ribbon, that allows an increase in the efficiency of glycosylation by creating enzymatic subcompartments in the order required for processing (Storrie et al, 1998; Storrie and Yang, 1998). The results indicate that the GA undergoes a profound and reversible morphological and neurochemical reorganization during the hibernation cycle that likely affects the ability to process and sort proteins

Methods

Results

Conclusion