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Neurotrophins stimulate the regeneration of neural tissue after lesions. It is also known that the sources of neurogenesis and cerebral function recovery are predominantly located in subcortical brain structures. The effects of ischemia on the expression of genes that encode neurotrophins (Bdnf, Ngf, Nt-3) and their receptors (TrkB, TrkA, TrkC, p75) in brain structures outside the lesion site were studied 3, 24, and 72 h after irreversible unilateral occlusion of the middle cerebral artery in rats. Changes in the mRNA expression of these genes were assessed by relative quantification using real-time RT-PCR. Sham surgery was found to stimulate the expression of genes that encode neurotrophins (Bdnf, Ngf) and their receptor (p75). It has been shown that ischemia influenced the expression of neurotrophins (Bdnf, Ngf, Nt-3) and their receptors (TrkB, TrkA, TrkC, p75) in brain structures outside the lesion focus, including the contralateral hemisphere. The downregulation of Bdnf and TrkB transcripts and Ngf and TrkA upregulation in the contralateral cortex on the first day of ischemia obviously reflected stress response. On day 3, Nt-3 transcription increased in all investigated structures outside the lesion focus. In the contralateral hemisphere, relative levels of TrkA and TrkC mRNA expression increased, while p75 expression decreased. Presumably, the observed changes in gene transcription serve to facilitate neuroplasticity and neural tissue regeneration.

Sphingomyelin synthase 1 (SMS1) is a vitally important enzyme responsible for the synthesis of sphingomyelin and diacylglycerol from phosphatidylcholine and ceramide in eukaryotic cells. Previously, we have investigated the structure of the human gene SGMS1 in detail and identified a lot of its transcripts. We have found mRNA isoforms that differ in their 5′-untranslated regions (UTRs) and encode a full-length protein. We have also detected the transcripts that arise from an alternative exon combination and comprise a coding region of the gene and a 3′-UTR. Computer analysis revealed that the synthesis of the transcripts differing in 5′-UTRs starts from different SGMS1 gene promoters. In the present study performed using the realtime PCR, we demonstrated that the contents of five alternative gene transcripts that differ in their 5′-UTRs is substantially dissimilar in the studied human tissues. The transcripts synthesized under the control of the distal promoter comprising exon 1 were the most abundant. The content of the transcripts comprising 5′-terminal exons, the synthesis of which is enabled by the promoters localized in the gene introns, is lower. Different contents of gene SGMS1 transcripts that differ in 5′-UTRs indicates that the use of certain alternative promoters is tissue-specific and, apparently, strictly regulated. The 5′-UTR structures of the SGMS1 gene transcripts controlled by alternative promoters differ significantly, which indicates that the gene functioning is regulated at the posttranscriptional level.

The investigation of molecular mechanisms contributing to cancer progression is the burning problem of current research. Considerable attention has been focused on the study of gene expression in cancer cells. Sphingomyelin synthase 1 gene (SGMS1) is one of the genes, the expression of which can be altered in cancer. SMS1 enzyme encoded by this gene catalyzes synthesis of sphingomyelin and diacylglycerol from phosphatidylcholine and ceramide. SMS1 may maintain the balance between cell death and survival by regulating the formation of the proaptotic mediator ceramide and anti-apoptotic mediator diacylglycerol. In addition, changes in the sphingomyelin level and sphingomyelin synthase activity have been observed in cancers of many tissues. However, the peculiarities of SGMS1 gene transcription have been insufficiently explored. In this work, the expression of transcripts of SGMS1 has been investigated by the method of real-time PCR in matched pairs of samples of human lung and esophagus cancer and adjacent tissues without pathology. A significant decrease in SMS1 transcript expression has been found in the samples of human lung cancer. At the same time, in the samples of human esophagus cancer and the adjacent tissues, the expression of SMS1 transcripts varies insignificantly, i.e., it is increased in seven and decreased in five of the fifteen samples. The obtained results indicate that SGMS1 gene is expressed differently in cancers of different genesis.

Tripeptide Pro-Gly-Pro (PGP) belongs to the group of biologically active regulatory peptides that are resistant to peptidases. This makes it possible to use it as a C-terminal fragment of peptide agents Semax and Selank. In recent years, the independent effects of PGP were revealed. The question was raised of whether PGP contributes to the action of pharmaceutical agents that contain this peptide as a fragment. Genome-wide analysis was performed to examine the PGP impacts on the transcriptome of rat cerebral cortex in experimental ischemia. We compared the gene expression levels in animals exposed to ischemia and PGP and in rats of the ischemia control group in 3 and 24 h after the permanent occlusion of the left middle cerebral artery. The altered expression of 29 genes was detected in 3 h, while the altered expression of 57 genes was detected in 24 h. The proteins encoded by these genes fulfill various functions, such as cytokines, transport proteins, transcription factors, transmembrane receptors, etc. Biological processes associated with the genes with altered expression under experimental conditions were determined. It was shown that PGP affects a number of processes involved in the functioning of various body systems. The expression of genes associated with the immune response process changed most significantly a day after the occlusion of the middle cerebral artery. The predominant effect of the suppression of the expression of the immune system genes was observed.

Vascular endothelial growth factor (VEGF-A) is hypoxia-inducible signal glycoprotein. VEGF-A induces vascular endothelial cell proliferation, which leads to the reconstitution of the vascular network in brain regions damaged by ischemia. However, this protein is also involved in the processes of inflammation and edema in early stages of ischemia. The synthetic peptide Semax has neuroprotective and anti-inflammatory properties and is actively used in the treatment of cerebral ischemia. We have previously shown that Semax reduces vascular injury and activates the mRNA synthesis of neurotrophins and their receptors during global cerebral ischemia in rats. In this work, we studied the effect of Semax and its C-terminal Pro-Gly-Pro tripeptide on Vegfa mRNA expression in different regions of the rat brain after 0.5, 1, 2, 4, 8, 12 and 24 h, which is the irreversible occlusion of the common carotid arteries. It was shown that ischemia increases the levels of Vegfa mRNA in rat brains (4 h after occlusion in cerebellum, cerebral cortex, and hippocampus; 8 h after occlusion in the cortex and hippocampus; and 24 h after occlusion in the cortex). Treatment with Semax reduces the levels of Vegfa mRNA in the frontal cortex (4, 8 and 12 h after occlusion) and the hippocampus (2 and 4 h after occlusion). The effect of PGP on the Vegfa gene expression was almost negligible. It was shown that Semax prevents the activating effect of hypoxia on the expression of the Vegfa gene at early stages of global cerebral ischemia. In turn, an increase in the level of Vegfa mRNA in the hippocampus 24 h after occlusion and Semax administration apparently reflects the neuroprotective properties of the drug.

Neurotrophins regulate key functions of nervous tissue cells. Analysis of neurotrophin mRNA expression is an appropriate tool to assess therapeutic efficiency of antistroke drugs. We have analyzed the effect of synthetic peptide semax and its C-terminal Pro-Gly-Pro tripeptide on mRNA expression of neurotrophins Ngf, Bdnf, and Nt-3 and their receptors TrkA, TrkB, TrkC, and p75 in rat frontal cortex, hippocampus, and cerebellum after bilateral common carotid artery occlusion. The animals were decapitated at 30 min and 1, 2, 4, 8, 12, and 24 h after the operation. The mRNA expression of neurotrophins and their receptors was assessed by relative quantification using real-time RT-PCR. Our results demonstrated that ischemia caused a significant decrease in gene expression in the hippocampus. Semax and PGP treatment affected the expression of neurotrophins and their receptors predominantly in the frontal cortex and hippocampus of the ischemized animals. In the frontal cortex, Semax treatment resulted in a decrease of mRNA level of neurotrophin receptors, while PGP treatment increased the level of these mRNA. Maximal neuroprotective effect of both peptides was observed in the hippocampus 12 h after occlusion. A decrease of gene expression of neurotrophins and their receptors caused by the occlusion was overcome by Semax and PGP. These results clarify the mechanism of Semax action and reveal certain features of mRNA expression of neurotrophins and their receptors under experimental conditions.

Parkinson’s disease (PD) is the second most common progressive neurodegenerative disorder characterized by the degeneration of dopaminergic neurons. Detecting changes in gene expression in untreated de novo patients with PD is important for understanding the disease pathogenesis and for identifying biomarkers of the preclinical stage of PD. In this study, the expression of the glycogen synthase kinase-3 beta gene (GSK3B) was investigated in the peripheral blood of several groups of neurological patients using reverse transcription reaction and real-time PCR. Our results suggest that the GSK3B expression level cannot serve as a biomarker for early stages of PD.

The review covers selected research topics in the fields of medical and ethnic genomics conducted at the Department of Molecular Bases of Human Genetics, the Institute of Molecular Genetics. Primary concern is given to genetic causes of monogenic neurological disorders, among them hepatolenticular degeneration (Wilson disease), torsion dystonia, and myotonic dystrophy. Results of polymorphic DNA marker surveys in Russia and neighboring countries are also presented.

A genomic clone hybridizing with brain-specific sequence Hfb1 was isolated from a chromosome 5 cosmid library. Hfb1 proved to correspond to a new gene exon which codes for a large 3"-untranslated region of the mRNA for synaptic protein complexin 2. Together with the 985-nt Hfb1 cDNA (EMBL Y15167) isolated previously from a cDNA library of the frontal cerebral cortex, the primary structure was established for genomic clone Ghfb sized more than 4 kb. A GenBank search revealed complete identity of the 5" end of Ghfb and the 3"-untranslated region (878–933) of the human complexin 2 mRNA. Large transcripts with the 5" end corresponding to the complexin 2 mRNA and the 3" end to Ghfb were detected in total mRNA of the human brain by means of RT-PCR. The size of the 3"-untranslated region of the human complexin 2 mRNA was estimated at 4 kb.