Downregulation of lncRNAs Gomafu, NONMMUT033604.2, and NONMMUT064397.2 in the hippocampus of mice with model of post-traumatic stress disorder.

OBJECTIVES: Molecular mechanisms of post-traumatic stress disorder (PTSD) development have been analysed by evaluati-ng changes in the expression level of long non-coding RNA (lncRNA) as a potential biomarker of the disease and as one of the molecular aspects associated with the disease development. METHODS: In our study, we used quantitative polymerase chain reaction (qPCR) to evaluate changes in the expression level of long non-coding RNA - Gomafu, NONMMUT033604.2, and NONMMUT064397.2 - in the hippocampus of mice that were subjected to an artificially induced middle single prolonged stress (mSPS) model of post-traumatic stress disorder. RESULTS: We found a significant reduction in the expression levels of each of the three lncRNAs tested: Gomafu in 45.4 times, NONMMUT033604.2 in 53.4 times, and NONMMUT064397.2 in 5.2 times. The results of the present study provide evidence that the mSPS model effectively induces PTSD-like behaviour in mice leading to a significant decrease in the expression level of Gomafu, NONMMUT033604.2 and NONMMUT064397.2 lncRNA in mice hippocampus. CONCLUSIONS: This data provides evidence that the three studied lncRNAs could be potential biomarkers of PTSD development.

Pure purr virtual reality technology: measuring heart rate variability and anxiety levels in healthy volunteers affected by moderate stress.

Introduction: Traditional approaches to stress management are difficult to learn and to implicate in daily life. Emerging technologies like virtual reality (VR) have become a target of extensive study for recreational and medical purposes. The autonomic nervous system (ANS) plays a crucial role in stress response, post-stress relaxation, and recovery. This study aimed to assess the effect of modified VR intervention on short-term heart rate variability (HRV) and perceived anxiety levels in healthy volunteers affected by moderate stress. The stressors included mental arithmetic tasks. Material and methods: The study involved healthy adults, of both sexes, aged 20 to 60 years, without history of cardiovascular diseases, essential abnormalities on ECG, and with normal or moderate level of situational anxiety. The VR gadgets used in the study were commercially available Bobo-VR X1 headsets, one with modification for medical applications (Pure Purr technology) and one with none (sham technology). The investigational (Pure Purr) headset with an audio-visual sequence was modified by adding a binaural effect and was synchronised with the tract of respiratory movements and the frequency of heart rate. To track changes in the ANS, participants underwent both electrocardiography (ECG) and measurement of HRV. Results: The findings showed a significant increase in parasympathetic activity after 5-minute exposure to the investigational device compared to stress, as shown by high-frequency HRV (499.8 ms2 and 340.5 ms2, p < 0.001). RMSSD for a modified headset was higher (p = 0.02) compared to a sham headset with no modifications (RMSSD difference of 12.3% (2.6% to 23.1%)). The LF/HF ratio, however, was lower (difference of 14.5% (2.6% to 23.1%), p = 0.04). Conclusions: These findings suggest that a medical device with pre-installed Pure Purr software had a significant effect on the recovery of the ANS in healthy volunteers affected by moderate stress.

Cardiac dysfunction in spontaneously hypertensive old rats is associated with a significant decrease of SUR2 expression.

ATP-sensitive potassium (KATP) channels are participants of mechanisms of pathological myocardial remodeling containment. The aim of our work was to find the association of changes in the expression of Kir6.1, Kir6.2, SUR1, and SUR2 subunits of KATP channels with changes in heart function and structure during aging under conditions of the constant increase of vascular pressure. The experiments were carried out on young and old spontaneously hypertensive rats (SHR) and Wistar rats. The expression levels of KATP channels subunits were determined using reverse transcription and quantitative PCR. It is shown that the mRNA expression level of Kir6.1 in young SHR rats is significantly lower (6.3-fold, p = 0.035) than that of young Wistar rats that may be one of the causes of arterial hypertension in SHR. At the same time, mRNA expression of both Kir6.1 and Kir6.2 in old SHR rats was significantly higher (6.8-fold, p = 0.003, and 5.9-fold, p = 0.006, respectively) than in young hypertensive animals. In both groups of old animals, SUR2 expression was significantly reduced compared to young animals, in Wistar rats at 3.87-fold (p = 0.028) and in SHR rats at 48.2-fold (p = 0.033). Changes in SUR1 expression were not significant. Thus, significant changes in the cardiovascular system, including impaired function and structure of the heart in old SHR rats, were associated with a significant decrease in SUR2 expression that may be one of the mechanisms of heart failure decompensation. Therefore, it can be assumed that increased expression of SUR2 may be one of the protective mechanisms against pathological myocardial remodeling.

Melanoma Extracellular Vesicles Generate Immunosuppressive Myeloid Cells by Upregulating PD-L1 via TLR4 Signaling.

Tumor cell-derived extracellular vesicles (EV) convert normal myeloid cells into myeloid-derived suppressor cells (MDSC), inhibiting antitumor immune responses. Here, we show that EV from Ret mouse melanoma cells upregulate the expression of programmed cell death ligand 1 (PD-L1) on mouse immature myeloid cells (IMC), leading to suppression of T-cell activation. PD-L1 expression and the immunosuppressive potential of EV-generated MDSC were dependent on the expression of Toll-like receptors (TLR). IMC from Tlr4-/- mice failed to increase T-cell PD-L1 expression and immunosuppression with Ret-EV treatment, and this effect was dependent on heat-shock protein 86 (HSP86) as HSP86-deficient Ret cells could not stimulate PD-L1 expression on normal IMC; IMC from Tlr2-/- and Tlr7-/- mice demonstrated similar results, although to a lesser extent. HSP86-deficient Ret cells slowed tumor progression in vivo associated with decreased frequency of tumor-infiltrating PD-L1+CD11b+Gr1+ MDSC. EV from human melanoma cells upregulated PD-L1 and immunosuppression of normal monocytes dependent on HSP86. These findings highlight a novel EV-mediated mechanism of MDSC generation from normal myeloid cells, suggesting the importance of EV targeting for tumor therapy. SIGNIFICANCE: These findings validate the importance of TLR4 signaling in reprogramming normal myeloid cells into functional myeloid-derived suppressor cells.

Altered biogenesis of microRNA-1 is associated with cardiac dysfunction in aging of spontaneously hypertensive rats.

Currently we face the issues of aging-associated pathologies, particularly those leading to heart failure. With that in mind, in current research we focus on aging and hypertension combination as a widely spread threating problem. In a row with functional and morphological characterization of these aging- and hypertension-associated cardiac changes, we evaluate biogenesis of microRNA-1 being one of major microRNAs in the heart. The aim of this study was to check the hypothesis if dysregulation of microRNA-1 biogenesis is associated with heart failure in aged and especially aged hypertensive rats. The experiments were carried out on male SHR and Wistar rats of age 6 months (young) and 18 months (old). The evaluation of hemodynamic parameters was performed in heart left ventricles of narcotized rats using the ultra-small 2F catheter. The development of fibrosis was determined using light and electron microscopy. Levels of mature and immature forms of microRNA-1 and mRNA encoding the proteins involved in its biogenesis were determined using reverse transcription and quantitative PCR. Aging of both Wistar and SHRs is accompanied with altered hemodynamic parameters compared with correspondent younger mates. SHRs, especially old ones, demonstrated significant heart fibrosis. In aged animals, the level of primary microRNA-1 in Wistar rats were 7 times higher (p < 0.05) and in SHR 17 times higher (p < 0.05) in comparison with young rats of the same strain. We also observed 22 times higher level of immature microRNA-1 in the heart of Wistar and 5.9 times higher level for aged hypertensive rats (p < 0.05) compared to young rats. At the same time, the level of mature microRNA-1 occurred 2.5 and 3.2 times lower in respective groups (p < 0.05). In the current study, we observe the significant dysregulation of microRNA-1 processing in the heart associated with aging and arterial hypertension.

shRNA-Induced Knockdown of a Bioinformatically Predicted Target IL10 Influences Functional Parameters in Spontaneously Hypertensive Rats with Asthma.

One of the most common comorbid pathology is asthma and arterial hypertension. For experimental modeling of comorbidity we have used spontaneously hypertensive rats with ovalbumin (OVA)-induced asthma. Rats were randomly divided into three groups: control group, OVA-induced asthma group; OVA-induced asthma + IL10 shRNA interference group. Target gene (IL10) was predicted by ANDSystem. We have demonstrated that RNA-interference of IL10 affected cardiovascular (tested using Millar microcatheter system) as well as respiratory functions (tested using force-oscillation technique, Flexivent) in rats. We have shown that during RNA-interference of IL10 gene in vivo there were changes in both cardiac and lung function parameters. These changes in the cardiovascular parameters can be described as positive. But the more intensive heart workload can lead to exhaust and decompensation of the heart functions. Knockdown of IL10 gene in asthma modeling induces some positive changes in respiratory functions of asthmatic animals such as decreased elastance and increased compliance of the lungs, as well as less pronounced pathomorphological changes in the lung tissue. Thus, we provide the data about experimentally confirmed functionality changes of the target which was in silico predicted to be associated with both asthma and hypertension - in our new experimental model of comorbid pathology.

Myeloid-Derived Suppressor Cells Hinder the Anti-Cancer Activity of Immune Checkpoint Inhibitors.

Immune checkpoint inhibitors (ICI) used for cancer immunotherapy were shown to boost the existing anti-tumor immune response by preventing the inhibition of T cells by tumor cells. Antibodies targeting two negative immune checkpoint pathways, namely cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1), and programmed cell death-ligand 1 (PD-L1), have been approved first for patients with melanoma, squamous non-small cell lung cancer (NSCLC), and renal cell carcinoma. Clinical trials are ongoing to verify the efficiency of these antibodies for other cancer types and to evaluate strategies to block other checkpoint molecules. However, a number of patients do not respond to this treatment possibly due to profound immunosuppression, which is mediated partly by myeloid-derived suppressor cells (MDSC). This heterogeneous population of immature myeloid cells can strongly inhibit anti-tumor activities of T and NK cells and stimulate regulatory T cells (Treg), leading to tumor progression. Moreover, MDSC can contribute to patient resistance to immune checkpoint inhibition. Accumulating evidence demonstrates that the frequency and immunosuppressive function of MDSC in cancer patients can be used as a predictive marker for therapy response. This review focuses on the role of MDSC in immune checkpoint inhibition and provides an analysis of combination strategies for MDSC targeting together with ICI to improve their therapeutic efficiency in cancer patients.

Targeting Myeloid-Derived Suppressor Cells to Bypass Tumor-Induced Immunosuppression.

The immune system has many sophisticated mechanisms to balance an extensive immune response. Distinct immunosuppressive cells could protect from excessive tissue damage and autoimmune disorders. Tumor cells take an advantage of those immunosuppressive mechanisms and establish a strongly immunosuppressive tumor microenvironment (TME), which inhibits antitumor immune responses, supporting the disease progression. Myeloid-derived suppressor cells (MDSC) play a crucial role in this immunosuppressive TME. Those cells represent a heterogeneous population of immature myeloid cells with a strong immunosuppressive potential. They inhibit an antitumor reactivity of T cells and NK cells. Furthermore, they promote angiogenesis, establish pre-metastatic niches, and recruit other immunosuppressive cells such as regulatory T cells. Accumulating evidences demonstrated that the enrichment and activation of MDSC correlated with tumor progression, recurrence, and negative clinical outcome. In the last few years, various preclinical studies and clinical trials targeting MDSC showed promising results. In this review, we discuss different therapeutic approaches on MDSC targeting to overcome immunosuppressive TME and enhance the efficiency of current tumor immunotherapies.

N-3 long chain polyunsaturated fatty acids increase the expression of PPARγ-target genes and resistance of isolated heart and cultured cardiomyocytes to ischemic injury.

BACKGROUND: The goal of present investigation is to check the hypothesis that cardioprotective effect of polyunsaturated fatty acids (PUFAs) is mediated by influence on mRNA expression level of the FATP, IL-1ra and GJP43 through stimulation of PPARγ. METHODS: Animals obtained n-3 PUFAs orally during 4 weeks (0.1ml/100g b.w. per day) or during prenatal period. In experiments, isolated perfused hearts were subjected to 20-min regional ischemia and 40min reperfusion. The hearts of newborn rats (2-3days old) were used for isolated cardiomyocytes culture preparing. Culture cells underwent 30min of anoxia followed by 60min of reoxygenation. Using rtPCR the level of FATP, IL-1ra, GJP43 and BCL2 mRNA in isolated cardiomyocyte and hearts was evaluated. RESULTS: The data obtained indicate that in heart tissues from pups with prenatal n-3 PUFAs application the level of LA and DHA acids were increased in 3.6-fold and 2-fold correspondingly comparing to control. In adult hearts the level of DHA was increased in 1.4-fold, and the level of EPA-in 6.9-fold. We observed the increase in mRNA level of PPARγ-target genes: FATP in 2.25 times, and IL-1ra in 8.4 times. At the same time the level of mRNA of antiapoptotic gene BCL2 was increased in 2.13 times and Connexin-43 gene in 2.2 times after n-3 PUFAs application. These effects were accompanied by significantly improved cardiac function, and increase of living cardiomyocytes number at modeling of ischemia-reperfusion. CONCLUSIONS: n-3 PUFAs application has cardioprotective effects and increases mRNA level of FATP, IL-1ra, GJP43, and BCL2 genes in culture of neonatal cardiomyocytes and in adult hearts.

Proteasome Inhibition Diminishes the Formation of Neutrophil Extracellular Traps and Prevents the Death of Cardiomyocytes in Coculture with Activated Neutrophils during Anoxia-Reoxygenation.

OBJECTIVE: Polymorphic mononuclear neutrophils (PMN) are very important cells participating in nonspecific defense of the organism. Among their well-known functions, the formation of neutrophil extracellular traps (NET) is interesting and potentially dangerous for the mechanisms of other cells. Ubiquitin-dependent proteasomal proteolysis is a very important regulator of all cellular activities, but the role of proteasomal proteolysis in NET formation has not been investigated. METHODS: We performed experiments with PMN activated to form NET with phorbol 12-myristate 13-acetate (PMA) and the application of a proteasome inhibitor. We also added activated neutrophils to primary culture of isolated rat neonatal cardiomyocytes with or without anoxia-reoxygenation modeling. RESULTS: The data obtained show that proteasomes participate in NET formation and proteasome inhibitors facilitate the blocking of the NET program. The percentage of NET after PMA application was 70.8 ± 7.2 and the proteasome inhibitor decreased this amount to 4.7 ± 0.9%. In coculture with cardiomyocytes during anoxia-reoxygenation, this effect prevented cardiac cell death induced by activated PMN. The stimulation of NET formation by PMA in coculture with isolated cardiomyocytes led to an increase in the number of necrotic cardiomyocytes of up to 33.1 ± 12.9% and a corresponding decrease in living cardiomyocytes to 66.9 ± 12.9%. The number of living cardiomyocytes in coculture after incubation with both PMA and proteasome inhibitor was 76.6 ± 13.3% (p < 0.05), and the number of necrotic cardiomyocytes was 23.4 ± 13.3% (p < 0.05). CONCLUSION: Proteasome inhibition blocks NET formation and prevents cardiomyocyte necrosis in coculture with activated neutrophils.

Knockdown of PSMB7 induces autophagy in cardiomyocyte cultures: possible role in endoplasmic reticulum stress.

Proteasomal and autophagic pathways of protein degradation are two essential, endoplasmic reticulum (ER)-associated proteolytic systems involved in the ER stress response. The functional interaction between them has been shown by proteasome pharmacological inhibition. However, little data have been found concerning autophagy induction using an RNA interference approach due to the multisubunit composition of proteolytic systems. We suggested that silencing of single proteasome subunits can induce massive autophagy. Psmb7-specific small interference RNA added to isolated cardiomyocytes significantly affected mRNA expression of essential ER stress marker proteins, including DDIT3/CHOP and HSPA5/GRP78. mRNA expression of the key autophagy regulator MTOR was also increased. These findings were confirmed by single-cell reverse transcription real-time PCR on individual monodansylcadaverine (MDC)-labeled cardiomyocytes. RNA interference that decreased the levels of non-catalytic PSMB7 subunits of the proteasome had no influence on chymotrypsin- and trypsin-like activities, but significantly decreased peptidyl-glutamyl peptide-hydrolyzing activity. Immunohistochemical analysis showed increased levels of LC3-marked vacuoles in the cytoplasm of Psmb7-knockdown cells, and MDC staining showed significantly increased numbers of neonatal cardiomyocytes with autophagic vacuoles. After anoxia-reoxygenation, the number of cells with signs of autophagy after Psmb7 gene silencing was higher. Our results indicate that Psmb7 knockdown induces ER stress and autophagy in cardiomyocytes, which may be a useful approach to activate specific autophagy.

Antiatherogenic effect of quercetin is mediated by proteasome inhibition in the aorta and circulating leukocytes.

Quercetin, a plant-derived flavonoid, has attracted considerable attention as promising compound for heart disease prevention and therapy. It has been linked to decreased mortality from heart disease and decreased incidence of stroke. Here, we report new data showing the angioprotective properties of quercetin mediated by its effect on proteasomal proteolysis. This study was designed to investigate the ability of quercetin to modulate proteasomal activity in a rabbit model of cholesterol-induced atherosclerosis. First, we show proteasomal trypsin-like (TL) activity increased up to 2.4-fold, chymotrypsin-like (CTL) activity increased by up to 43% and peptidyl-glutamyl peptide-hydrolyzing (PGPH) activity increased by up to 10% after 8 weeks of a cholesterol-rich diet. A single intravenous injection of the water-soluble form of quercetin (Corvitin) significantly decreased proteasomal TL activity 1.85-fold in monocytes, and decreased the CTL and PGPH activities more than 2-fold in polymorphonuclear leukocytes (PMNL) after 2 h. Prolonged administration (1 month) of Corvitin to animals following a cholesterol-rich diet significantly decreased all types of proteolytic proteasome activities both in tissues and in circulating leukocytes and was associated with the reduction of atherosclerotic lesion areas in the aorta. Additionally, the pharmacological form of quercetin (Quertin) was shown to have an antiatherogenic effect and an ability to inhibit proteasome activities.

Cardioprotective effect of 5-lipoxygenase gene (ALOX5) silencing in ischemia-reperfusion.

It is well known that 5-lipoxygenase derivates of arachidonic acid play an important pathogenic role during myocardial infarction. Therefore, the gene encoding arachidonate 5-lipoxygenase (ALOX5) appears to be an attractive target for RNA interference (RNAi) application. In experiments on cultivated cardiomyocytes with anoxia-reoxygenation (AR) and in vivo using rat model of heart ischemia-reperfusion (IR) we determined influence of ALOX5 silencing on myocardial cell death. ALOX5 silencing was quantified using real-time PCR, semi-quantitative PCR, and evaluation of LTC(4) concentration in cardiac tissue. A 4.7-fold decrease of ALOX5 expression (P < 0.05) was observed in isolated cardiomyocytes together with a reduced number of necrotic cardiomyocytes (P < 0.05), increased number live (P < 0.05) and unchanged number of apoptotic cells during AR of cardiomyocytes. Downregulation of ALOX5 expression in myocardial tissue by 19% (P < 0.05) resulted in a 3.8-fold reduction of infarct size in an open chest rat model of heart IR (P < 0.05). Thus, RNAi targeting of ALOX5 protects heart cells against IR injury both in culture and in vivo.

Effect of a low dose of proteasome inhibitor on cell death and gene expression in neonatal rat cardiomyocyte cultures exposed to anoxia-reoxygenation.

BACKGROUND: Recent data suggest that low concentrations of proteasome inhibitors (PIs) are cytoprotective in models of ischemia-reperfusion injury, but the underlying mechanisms of this effect still remain unclear. AIM: To investigate the effect of 100 nM of clasto-lactacystin beta-lactone on cell death and gene expression in neonatal rat cardiomyocytes exposed to anoxia-reoxygenation. METHODS: Fluorescent microscopy and real-time polymerase chain reaction were used to detect different types of cell death and gene expression, respectively, in neonatal rat cardiomyocyte cultures exposed to anoxia-reoxygenation. RESULTS: It was shown that a low dose of clasto-lactacystin beta-lactone protected the cells against anoxia-reoxygenation injury by a reduction in the number of necrotic and apoptotic cells. The number of autophagic cells was greatly increased by proteasomal inhibition. The PI increased the heat shock protein 70 messenger RNA expression twofold and slightly reduced the expression of heat shock protein 90 gene. The expression of the FK506 binding protein 12-rapamycin associated protein gene was increased 1.57-fold on PI application. The B-cell lymphoma 2 gene expression was unaffected by the use of clasto-lactacystin beta-lactone in low dose. CONCLUSION: Although PIs are injurious, they may be cardioprotective in low doses; ie, they do not result in cell death. Moreover, PIs initiate the protective mechanisms that prevent cell damage by changing the expression of several genes.

Effects of late postconditioning on gene expression and cell death in neonatal rat cardiomyocyte cultures.

The cell death and gene expression in neonatal cardiomyocyte cultures were investigated in a late postconditioning model. The primary cultures were subjected to a 30min of anoxia followed by 60min or 24h of reoxygenation. Postconditioning was carried out in three cycles of 1min reoxygenations followed by 1min anoxia, respectively. After 24h of reperfusion the percentages of living, necrotic, and apoptotic cells were determined by staining with bis-benzimide and propidium iodide. Anoxia-reoxygenation significantly increased the necrotic and apoptotic cells both at its first and second episodes. Postconditioning in remote period did not protect the cells from the second anoxia. Postconditioning decreased the anoxia-reoxygenation-induced increase of HSP70 and HSP90 mRNA expression. We observed a decrease of HIF-3alpha gene expression in remote postconditioning. The FRAP gene expression was leveled to control value. Thus, the changes of mRNA gene expression did not show cytoprotection of cardiomyocytes in remote postconditioning model.

Protective effect of autophagy in anoxia-reoxygenation of isolated cardiomyocyte?

Preconditioning and postconditioning increased numbers of living cells and decreased that of necrotic, apoptotic and autophagic cells in anoxia-reoxygenation of isolated cardiomyocytes. It was established that proteasome inhibitors prevented the necrotic and apoptotic cell death of cardiomyocytes in anoxia-reoxygenation and in such a way reproduce the effect of pharmacological preconditioning and postconditioning. In this case, the population of autophagic cardiomyocytes has not changed considerably or had a tendency of increasing compared to anoxia-reoxygenation. The data obtained showed that the specific protective effect of proteasome inhibitors could be caused by autophagy activation. In our recent experiments new data supporting this hypothesis were obtained. The inhibition of autophagy with N-3-methyladenine during anoxia-reoxygenation caused an increase in the number of necrotic cells and a decrease of the live cell population. Moreover, simultaneous inhibition of both autophagy and apoptosis (N-3-methyladenine and caspase-3 inhibitor application) in anoxia-reoxygenation led to a dramatic increase of necrotic cardiomyocytes and a concomitant decrease in the number of living cells. Thus, the process of autophagy in cardiomyocytes during anoxia-reoxygenation may lead not only to programmed cell death, but has also some protective effect. The mechanisms of this phenomenon are still in need of thorough investigation.

Proteasomal proteolysis in anoxia-reoxygenation, preconditioning and postconditioning of isolated cardiomyocytes.

The role of proteasomal proteolysis in the pathogenesis of ischemia-reperfusion is being actively studied. To evaluate the participation of the proteasome in the preconditioning and postconditioning phenomena we used primary culture of neonatal cardiomyocytes. This culture was undergone 30min of anoxia followed by 60min of reoxygenation. Preconditioning was modeled by three cycles of 3min anoxia followed by 3min reoxygenation. Postconditioning was modeled by three cycles of 1min reoxygenation followed by 1min anoxia, respectively. Clasto-lactacystin beta-lactone, a specific proteasome inhibitor, was added to the culture medium right before the cycles of preconditioning or postconditioning in the dose that does not cause cell death (2.5muM). Percentages of living, necrotic, and apoptotic cells were determined by staining with bisbenzimide and propidium iodide. Autophagy was demonstrated by staining vacuolar structures with monodansyl cadaverine. Proteasomal activity was determined by cleavage intensity of specific fluorogenic substrates. Trypsin-like, chymotrypsin-like and peptidyl-glutamyl peptide-hydrolyzing (PGPH) activities were decreased after anoxia. Reoxygenation has led to the increase in trypsin-like and chymotrypsin-like activities comparing to anoxia, but these parameters have never reached the control levels. PGPH activity has been restored up to the initial level. Preconditioning and postconditioning increased numbers of living cells and decreased that of necrotic, apoptotic and autophagic cells. Paradoxically, it was established that proteasome inhibitors prevented the necrotic and apoptotic cell death of cardiomyocytes in anoxia-reoxygenation, but in the same concentration abolished the effects of preconditioning and postconditioning. Low doses of proteasome inhibitors, particularly the ones used in our experiments, resulted in the abolishing of preconditioning and postconditioning phenomena, but at the same time led to the increase of the population of living cells in anoxia-reoxygenation, and can be considered as potential pharmacological agents of preconditioning and postconditioning.