Abstracts from the 20th International Symposium on Signal Transduction at the Blood-Brain Barriers

https://deepblue.lib.umich.edu/bitstream/2027.42/138963/1/12987_2017_Article_71.pd

Copy Number of Human Ribosomal Genes With Aging: Unchanged Mean, but Narrowed Range and Decreased Variance in Elderly Group

Introduction: The multi-copied genes coding for the human 18, 5.8, and 28S ribosomal RNA (rRNA) are located in five pairs of acrocentric chromosomes forming so-called rDNA. Human genome contains unmethylated, slightly methylated, and hypermethylated copies of rDNA. The major research question: What is the rDNA copy number (rDNA CN) and the content of hypermethylated rDNA as a function of age?Materials and Methods: We determined the rDNA CN in the blood leukocyte genomes of 651 subjects aged 17 to 91 years. The subjects were divided into two subgroups: “elderly” group (E-group, N = 126) – individuals over 72 years of age (the age of the population’s mean lifetime for Russia) and “non-elderly” group (NE-group, N = 525). The hypermethylated rDNA content was determined in the 40 DNA samples from the each group. The change in rDNA during replicative cell senescence was studied for the cultured skin fibroblast lines of five subjects from NE-group. Non-radioactive quantitative dot- and blot-hybridization techniques (NQH) were applied.Results: In the subjects from the E-group the mean rDNA CN was the same, but the range of variation was narrower compared to the NE-group: a range of 272 to 541 copies in E-group vs. 200 to 711 copies in NE-group. Unlike NE-group, the E-group genomes contained almost no hypermethylated rDNA copies. A case study of cultured skin fibroblasts from five subjects has shown that during the replicative senescence the genome lost hypermethylated rDNA copies only.Conclusion: In the elderly group, the mean rDNA CN is the same, but the range of variation is narrower compared with the younger subjects. During replicative senescence, the human fibroblast genome loses hypermethylated copies of rDNA. Two hypotheses were put forward: (1) individuals with either very low or very high rDNA content in their genomes do not survive till the age of the population’s mean lifetime; and/or (2) during the aging, the human genome eliminates hypermethylated copies of rDNA

Application of Fluorescence Spectroscopy for Assesment of Myocardial Ischemic Injury

Представлены результаты экспериментального исследования возможности применения лазерно-флуоресцентного анализа миокарда для оценки повреждения, индуцированного ишемией в условиях кардиохирургического вмешательства. Доказано, что метод оптической биопсии с использованием азотного лазера (337 нм) позволяет регистрировать метаболические изменения в миокарде, проявляющиеся нарушением уровня пиридиновых нуклеотидов, изменением функции гемопротеидов, активности НАД(Ф)Н-утилизирующих процессов и развитием контрактуры и гибели кардиомиоцитов.Data of experimental assessment of a possibility to use laser-fluorescent analysis of myocardium for detecting alterations caused by ischemia under the conditions of cardiac surgery are presented. It is confirmed that the method of optical biopsy with Nitrogen laser (337 nm) allows registering metabolic changes in myocardium associated with alterations in pyridine nucleotides concentrations, dysfunction of hemoproteids, changes in the activity of NAD(P)H-utilizing enzymes, and development of contraction and death of cardiomyocytes

Application of Fluorescence Spectroscopy for Assesment of Myocardial Ischemic Injury

Представлены результаты экспериментального исследования возможности применения лазерно-флуоресцентного анализа миокарда для оценки повреждения, индуцированного ишемией в условиях кардиохирургического вмешательства. Доказано, что метод оптической биопсии с использованием азотного лазера (337 нм) позволяет регистрировать метаболические изменения в миокарде, проявляющиеся нарушением уровня пиридиновых нуклеотидов, изменением функции гемопротеидов, активности НАД(Ф)Н-утилизирующих процессов и развитием контрактуры и гибели кардиомиоцитов.Data of experimental assessment of a possibility to use laser-fluorescent analysis of myocardium for detecting alterations caused by ischemia under the conditions of cardiac surgery are presented. It is confirmed that the method of optical biopsy with Nitrogen laser (337 nm) allows registering metabolic changes in myocardium associated with alterations in pyridine nucleotides concentrations, dysfunction of hemoproteids, changes in the activity of NAD(P)H-utilizing enzymes, and development of contraction and death of cardiomyocytes

Changes of KEAP1/NRF2 and IKB/NF-κB Expression Levels Induced by Cell-Free DNA in Different Cell Types

Cell-free DNA (cfDNA) is a circulating DNA of nuclear and mitochondrial origin mainly derived from dying cells. Recent studies have shown that cfDNA is a stress signaling DAMP (damage-associated molecular pattern) molecule. We report here that the expression profiles of cfDNA-induced factors NRF2 and NF-κB are distinct depending on the target cell’s type and the GC-content and oxidation rate of the cfDNA. Stem cells (MSC) have shown higher expression of NRF2 without inflammation in response to cfDNA. In contrast, inflammatory response launched by NF-κB was dominant in differentiated cells HUVEC, MCF7, and fibroblasts, with a possibility of transition to massive apoptosis. In each cell type examined, the response for oxidized cfDNA was more acute with higher peak intensity and faster resolution than that for nonoxidized cfDNA. GC-rich nonoxidized cfDNA evoked a weaker and prolonged response with proinflammatory component (NF-κB) as predominant. The exploration of apoptosis rates after adding cfDNA showed that cfDNA with moderately increased GC-content and lightly oxidized DNA promoted cell survival in a hormetic manner. Novel potential therapeutic approaches are proposed, which depend on the current cfDNA content: either preconditioning with low doses of cfDNA before a planned adverse impact or eliminating (binding, etc.) cfDNA when its content has already become high