Identification of potential therapeutic targets for gliomas by bioinformatics analysis
ONCOLOGY LETTERS
Authors: Ma, Ke; Cheng, Zhihua; Sun, Liqun; Li, Haibo
Abstract
Gliomas are primary tumors that originate in the brain or spinal cord and develop from supportive glial cells. The present study aimed to identify potential candidate molecular markers for the treatment of gliomas, and to explore the underlying mechanisms of this disease. The gene expression profile data GSE50021, which consisted of 10 specimens of normal brain tissues and 35 specimens of glioma tissues, was downloaded from Gene Expression Omnibus (GEO). The methylation microarray data GSE50022, consisting of 28 glioma specimens, was also downloaded from GEO. Differentially expressed genes (DEGs) between patients with glioma and normal individuals were identified, and key methylation sites were screened. Transcriptional regulatory networks were constructed, and target genes were selected. Survival analysis of key methylation sites and risk analysis of sub-pathways were performed, from which key genes and pathways were selected. A total of 79 DEGs and 179 key methylation sites were identified, of which 20 target genes and 36 transcription factors were included in the transcriptional regulatory network. Glutamate metabotropic receptor 2 (GRM2) was regulated by 8 transcription factors. Inositol-trisphosphate 3-kinase A (ITPKA) was a significantly enriched DEG, associated with the inositol phosphate metabolism pathway, Survival analysis revealed that the survival time of patients with lower methylation levels in cg00157228 was longer than patients with higher methylation levels. ITPKA was the closest located gene to cg00157228. In conclusion, GRM2 and enriched ITPKA, associated with the inositol phosphate metabolism pathway, may be key mechanisms in the development and progression of gliomas. Furthermore, the present study provided evidence for an additional mechanism of methylation-induced gliomas, in which methylation results in the dysregulation of specific transcripts. The results of the present study may provide a research direction for studying the mechanisms underlying the development and progression of gliomas.
The Long-Term Effects of Early Postnatal Stress on Cognitive Abilities and Expression of Genes of the Glutamatergic System in Mice
NEUROCHEMICAL JOURNAL
Authors: Reshetnikov, V. V.; Lepeshko, A. A.; Ryabushkina, Yu. A.; Studenikina, A. A.; Merkulova, T. I.; Bondar, N. P.
Abstract
Stressing events in the early period of life affect neuronal plasticity and cognitive functions in adulthood. A key role in the mechanisms of formation of memory and attention is played by the glutamatergic system. However, there has been virtually no systematic study on the effect of early postnatal stress on the expression of glutamatergic system genes in various regions of the brain in mice. In this study, we used two types of early postnatal stress: prolonged separation of pups from mothers (for 3 hours per day) and shortterm separation (15 minutes per day) during the first 2 weeks of life. We used an object recognition test to evaluate attention and memory to assess cognitive abilities in adults. We found that prolonged maternal separation reduced the ability to recognize a novel object and also disrupted motor and exploratory activities in adult animals, while short-term separation did not affect the studied parameters. We assessed the expression of the major genes of the glutamatergic system (AMPA receptor subunits Gria1, Gria2; NMDA subunits Grin1, Grin2a, and Grin2b; metabotropic receptor subunits Grm1, Grm2, and Grm3; glutamate transporters Vglut2, Eaat2, and Rab4a) in the frontal cortex, hippocampus, and hypothalamus. In the group with prolonged maternal separation, we found a decrease in the expression of Grin2b in the hypothalamus in comparison with the control, which led to a decrease in the mRNA ratio of this subunit to Grin2a mRNA, and possibly to a change in the ratio of these subunits in the NMDA receptor. In spite of the revealed cognitive impairments, we did not find significant changes in the expression of genes in the frontal cortex and hippocampus. Shortterm daily separation from mothers did not lead to changes in cognitive abilities and expression of genes of the glutamatergic system in mice. Thus, our results show that prolonged maternal separation may lead to a redistribution of the receptor subunits in the hypothalamus, which can modify the activity of the HPAA and determine the response to stress in these mice.