Abstract

Corticosterone (CORT) is the main glucocorticoid hormone involved in stress responses in rodents. It is established that CORT exerts its effects via glucocorticoid receptor (GR) and mineralocorticoid receptor that regulate downstream gene expression during development and adulthood. In our previous study, we have shown that maternal separation on postnatal day 15 increases DNA methyltransferase (DNMT) 1, 3A and 3B expression levels in rat nucleus accumbens lasting into adulthood (Anier et al. 2014). However, the exact mechanism how maternal separation alters DNMT expression is unclear. We hypothesize that stress-induced GR stimulation may increase the expression levels of DNMTs and alter long-term DNA methylation-demethylation balance in infant rat brain. Our aim is to evaluate the effect of CORT and maternal separation on the expression levels of DNMTs in rat cortex. In rat primary cortical neurons, CORT treatment increased mRNA levels of DNMT3A and DNMT3B. GR antagonist mifepristone significantly decreased CORT-induced DNMTs mRNA levels indicating GR stimulation-dependent upregulation of DNMTs expression. Higher mRNA levels of DNMT1, DNMT3A and DNMT3B in rat cortex at postnatal day 15 and increased plasma CORT levels suggest that elevated CORT upregulates DNMTs expression. Our results indicated that DNMTs are downstream targets of GR-dependent CORT stimulation and early life stress may induce aberrant DNA methylation pattern that could facilitate long-term changes in gene expression.

Highlights

  • Alzheimer’s disease (AD) is an incurable neurodegenerative disease characterized by progressive dementia

  • The results of the present study indicate that development of the neuronal hypoxic tolerance induced by the three-trial, in contrast to one-trial, mild hypoxic preconditioning is apparently largely associated with the activation of CREB, as well as brain-derived neurotrophic factor (BDNF) and Bcl-2 overexpression

  • No significant differences in serum level of Solubile form of RAGE (sRAGE) where found between rapidly progressing and slow progressing subgroup of multiple sclerosis (MS) patients.Our results suggest for the role of sRAGE in MS ethiopathogenesis, but we did not find any association of sRAGE in serum with the rate of MS disability progression

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Summary

Introduction

Alzheimer’s disease (AD) is an incurable neurodegenerative disease characterized by progressive dementia. The aim of the study was to characterize the effects of streptozocin (STZ)-indced diabetes on learning and memory of 5XFAD and wild-type (WT) mice in Morris water maze (MWM) at ages 2 and 6 months and on brain amyloid load. Existing evidence suggests GABAergic system is involved in pathophysiology of Alzheimer’s disease (AD) via inhibitory interneuron deficits (Verret et al, 2012) and decrease in functional GABAA receptors (Limon et al, 2012). Our concept: low doses of muscimol may prevent learning/memory deficits in intracerebroventricular (icv) streptozocin (STZ)-induced AD nontransgenic rat model. The Sigma-1 receptor is a chaperone protein that modulates intracellular calcium signalling of the endoplasmatic reticulum and is involved in learning and memory processes.The aim of the present study was to compare in vitro Ca2+ concentration modulating activity and in vivo behavioural effects of enantiomers of methylphenylpiracetam, a novel positive allosteric modulator of Sigma-1 receptors

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