Background: Myocardial ischemia-reperfusion (IR) injury is associated with dysregulated Ca2+ handling and oxidative stress, particularly in the middle-aged heart. Sarcoplasmic reticulum (SR)-mitochondria communication via mitochondria-associated membranes (MAMs) is essential for coordinating Ca2+ transfer and redox signaling; however, its role in IR injury in the middle-aged myocardium remains incompletely understood. This study investigated changes in cardiac MAM protein composition and associated functional and oxidative parameters during ischemia and IR. Methods: Middle-aged rat hearts were subjected to global ischemia or IR using the Langendorff perfusion model. Mitochondrial, MAM, and homogenate fractions were analyzed using biochemical, proteomic, and functional assays to assess Ca2+-handling proteins, redox enzymes, lipid peroxidation markers, and mitochondrial antioxidant defenses. Results: Myocardial ischemia and IR disrupted SR-mitochondria communication in middle-aged hearts, leading to impaired Ca2+ handling, redox imbalance, and reduced contractile recovery. Ischemia induced significant MAM remodeling, characterized by reduced mitofusin 2 levels and increased enrichment of voltage-dependent anion channel 1. These changes were associated with disturbed mitochondrial Ca2+ signaling, impaired SR Ca2+ sequestration. Although mitochondrial antioxidant defenses, including MnSOD, were largely preserved, IR was associated with compartment-specific redox alterations within MAMs, as inferred from altered redox enzyme activity and enhanced lipid peroxidation. Conclusions: Disruption of SR-mitochondria coupling and MAM-associated redox regulation represents a key mechanism underlying increased vulnerability to IR injury in the middle-aged heart. Targeting MAM integrity and modulating Ca2+-redox cross-talk may improve cardiac resilience in elderly populations.

To investigate how acute ischemic stroke induces systemic metabolic reorganization and to characterize the temporal dynamics of these alterations in relation to stroke severity. Blood plasma samples were collected from patients (n = 42) with acute ischemic stroke, including individuals undergoing mechanical thrombectomy, at two time points: within 24 h and five days after stroke onset. Analysed were circulating metabolites linked to energy metabolism and the most abundant amino acids. Stroke triggered rapid and systemic metabolic changes, including altered circulating glucose and lactate levels indicative of shifts in substrate utilization and inter-tissue energy redistribution. Ketone body concentrations were elevated, providing alternative fuels for metabolically stressed tissues. The magnitude and timing of systemic changes, including dynamic modulation of amino acids, were proportional to ischemic severity, demonstrating a graded physiological response. This study provides a characterization of the dynamic metabolic response to acute ischemic stroke, revealing extensive alterations in energy metabolism, amino acid pathways, and systemic metabolic regulation. Certain exhibited rapid changes that nearly normalized by Day 5, whereas other metabolites, including specific amino acids, showed delayed responses, highlighting the temporal heterogeneity of post-stroke metabolic response. The interconnection of metabolic pathways underscores that post-stroke alterations extend beyond isolated processes, forming a systemic network of biochemical interactions that may affect recovery trajectories and peripheral organ function. These findings provide insight into inter organ-level coordination after stroke and highlight the potential of plasma metabolomic profiling for monitoring systemic responses and recovery following cerebral ischemic events.

Background: Glioblastoma (GBM) is the most aggressive primary brain tumour in adults and is characterised by poor prognosis and frequent resistance to temozolomide (TMZ)-based chemotherapy. Increasing evidence suggests that long non-coding RNAs (lncRNAs) contribute to GBM progression, therapeutic adaptation, and chemoresistance. This study investigated the relationship between TMZ responsiveness and the expression of selected lncRNAs in GBM cell lines exhibiting distinct sensitivity profiles. Methods: Human GBM cell lines (A172, U87, and T98G) and normal human astrocytes (NHA) were exposed to TMZ for 24–72 h. Cell viability, cell cycle distribution, MGMT protein expression, and expression levels of nine selected lncRNAs were analysed using MTT assay, flow cytometry, Western blot, and quantitative RT-PCR, respectively. Results: TMZ induced dose- and time-dependent reductions in cell viability in all analysed cell lines. A172 cells exhibited the greatest TMZ sensitivity, whereas T98G cells displayed the highest resistance. TMZ-sensitive GBM cells demonstrated pronounced G2/M cell cycle arrest, while T98G cells showed minimal cell cycle perturbation. MGMT protein expression was markedly elevated in T98G cells and decreased following exposure to higher TMZ concentrations. Distinct lncRNA expression profiles were identified among GBM cell lines. MALAT1 expression was consistently reduced, whereas NCK1-AS1 was strongly upregulated, particularly in T98G cells. TMZ exposure induced significant alterations in H19, PVT1, OIP5-AS1, and NCK1-AS1 expression, suggesting their potential involvement in adaptive resistance mechanisms. Conclusions: Collectively, these findings indicate that selected lncRNAs, particularly H19, MALAT1, NCK1-AS1, and PVT1, may contribute to TMZ resistance in GBM and could be promising biomarkers and therapeutic targets for precision oncology approaches.

The aim of the present study was to examine the impact of LS-102, an inhibitor of enzymatic activity of HRD1 that is an essential E3 ubiquitin ligase of endoplasmic reticulum associated degradation (ERAD) on survival of the human cell lines derived from glioblastoma multiforme (GBM), neuroblastoma, and astrocytes. We have also examined molecular responses to HRD1 inhibition with a focus on proteins playing an essential role in unfolded protein response (UPR) and ERAD. In addition, activation of IRE1α documented by XBP1 splicing was investigated. Finally, we have examined the impact of LS-102 on p53 expression in GBM cells. Inhibition of HRD1 enzymatic activity results in cell death of all tested cells. With respect to GBM cells, U87 cells are more sensitive to LS-102 as T98G cells. Cells of cell lines derived from normal astrocytes K1884 exhibit the highest sensitivity to LS-102 among all cell types used in the study while NHA cells are the most resistant. Sensitivity of neuroblastoma SH-SY5Y cells to LS-102 is comparable to the sensitivity of U87 cells. In GBM cells, inhibition of HRD1 results in induction of the expression of proteins playing an essential role in UPR and ERAD (HRD1, SEL1L, and GRP78). XBP1 splicing induced by HRD1 inhibition was documented in T98G and K1884 cells. We did not observe induction of p53 expression in U87 cells. Since LS-102 induces cell death of normal astrocytes, it is not a candidate for the testing of its potential use as an antitumor treatment of GBM.

Up-to-date data on roles of ATP‑sensitive potassium (KATP) channels indicate their emerging roles in neurodegeneration. The aim of present study was to evaluate the significance of KATP channels on cell viability, calcium dynamics, and mitochondrial morphology with the accent on their intracellular localization. We distinguished between whole-cell KATP effects and specific effects of mitochondrial KATP under both physiological conditions and pathological conditions simulating in vitro Parkinson´s-type neurodegeneration. SH‑SY5Y cells with its high fidelity to dopaminergic neurons were treated for 24 h with the non‑selective KATP opener pinacidil and blocker glibenclamide, or with the mitochondrial KATP opener diazoxide and blocker 5‑hydroxydecanoate (5HD). The effects of modulators were analysed alone or alongside with rotenone, which is widely used as an inducer of Parkinson´s-type neurodegeneration. Intracellular calcium distribution and mitochondrial rebuild pattern was evaluated using the cell segmentation performed by fluorescent confocal microscopy. Although none of the KATP modulators reversed the negative effects of rotenone, significant and selective effects of mitochondrial KATP modulation on calcium homeostasis and mitochondrial morphology were observed. For antagonists, both compounds showed consistent effects, with non-selective glibenclamide exerting stronger effects, particularly in elevating calcium. More distinctive results were obtained for agonists: both reduced calcium concentration; however, pinacidil tended to induce mitochondrial fragmentation, an effect absent in diazoxide-treated cells. Furthermore, strong correlations were identified between calcium levels and several mitochondrial and cell viability parameters.

The aim of our work was to study impact of tauroursodeoxycholic acid (TUDCA), 4-phenylbutyric acid (PBA) and their combination on mitochondrial functions and morphology. TUDCA, PBA and their combination have a significant impact on mitochondrial respiration. Although both TUDCA and PBA are considered to be chemical chaperones influencing endoplasmic reticulum (ER) stress, they affect mitochondrial respiration in a specific way. While TUDCA decreases ROUTINE, maximal, succinate-driven maximal, ATP-coupled and leak respirations; PBA increases spare respiratory capacity (SRC). Combination of TUDCA with PBA increases ROUTINE, maximal, succinate driven maximal and ATP-coupled respirations and SRC. TUDCA, PBA and their combination exhibits positive impact on mitochondria elongation and do not induce expression of proteins involved in mitochondrial fusion and unfolded protein response. Our results do not indicate the impact of either TUDCA or PBA on ER stress since pre-treatment of the cells with either TUDCA or PBA does not significantly affect tunicamycin-induced expression of HRD1, GRP78 and SEL1L. The impact of PBA and combination of TUDCA with PBA on mitochondrial functions might be associated with their possible neuroprotective effects. Although TUDCA exhibits positive effect on inner mitochondrial membrane, the possible neuroprotective effect of TUDCA might involve mechanism distinct from modification of mitochondrial functions.

OBJECTIVES: Histone deacetylases (SHDAC) are enzymes that catalyse removal of acetyl group from lysine side chains of histones and non-histone proteins. Inhibitors of HDAC (HDACi) are extensively studied because of their ability to induce death of tumour cells. HDACi are also studied as neuroprotective molecules in different models of neurodegenerative diseases. We have examined impact of HDACi, butyrate and vorinostat, on relative survival of SH-SY5Y cells and intracellular stress response. METHODS: Relative cell survival was determined by MTT assay and light microscopy. The expression of the key stress proteins was determined by Western blot analysis. RESULTS: We have shown that both butyrate and vorinostat have significant negative impact on relative survival of SH-SY5Y cells. Treatment of the cells with vorinostat was associated with significantly increased expression of HRD1 that is protein of ER stress response. Expression of HRD1 was also elevated in the cells treated with butyrate but the increase was not statistically significant. Both butyrate and vorinostat did not significantly affect expression of mitochondrial HSP60 as a protein of mitochondrial stress and HSP70 that is upregulated after proteasome stress. CONCLUSION: Negative impact of vorinostat on survival of neuronal cells could account for neuropathy observed as an adverse effect of the treatment of cutaneous T-cell lymphoma with vorinostat. The potential of HDACi including vorinostat to induce ER stress proteins is probably not associated with neuproprotective effects of HDACi.

Inward rectifying potassium channels sensitive to ATP levels (KATP) have been the subject of investigation for several decades. Modulators of KATP channels are well-established treatments for metabolic as well as cardiovascular diseases. Experimental studies have also shown the potential of KATP modulation in neurodegenerative disorders. However, to date, data regarding the effects of KATP antagonists/agonists in experiments related to neurodegeneration remain inconsistent. The main source of confusion in evaluating available data seems to be the choice of experimental models. The present study aims to provide a comprehensive understanding of the effects of both opening and blocking KATP channels in two forms of SH-SY5Y cells. Our results offer valuable insights into the significance of metabolic differences between differentiated and non-differentiated SH-SY5Y cells, particularly in the context of glibenclamide and diazoxide effects under normal conditions and during the initiation of pathological events simulating Parkinson's disease in vitro. We emphasize the analysis of mitochondrial functions and changes in mitochondrial network morphology. The heightened protein expression of KATP channels identified in non-differentiated SH-SY5Y cells seems to be a platform for a more significant impact of KATP modulators in this cell type. The efficiency of rotenone treatment in inducing morphological changes in the mitochondrial network depends on the differentiation status of SH-SY5Y cells.

Matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) play critical roles in regulating processes associated with malignant behavior. These endopeptidases selectively degrade components of the extracellular matrix (ECM), growth factors, and their receptors, contributing to cancer cell invasiveness and migratory characteristics by disrupting the basal membrane. However, the expression profile and role of various matrix metalloproteinases remain unclear, and only a few studies have focused on differences between diagnoses of brain tumors. Using quantitative real-time PCR analysis, we identified the expression pattern of ECM modulators (n = 10) in biopsies from glioblastoma (GBM; n = 20), astrocytoma (AST; n = 9), and meningioma (MNG; n = 19) patients. We found eight deregulated genes in the glioblastoma group compared to the benign meningioma group, with only MMP9 (FC = 2.55; p = 0.09) and TIMP4 (7.28; p < 0.0001) upregulated in an aggressive form. The most substantial positive change in fold regulation for all tumors was detected in matrix metalloproteinase 2 (MNG = 30.9, AST = 4.28, and GBM = 4.12). Notably, we observed an influence of TIMP1, demonstrating a positive correlation with MMP8, MMP9, and MMP10 in tumor samples. Subsequently, we examined the protein levels of the investigated MMPs (n = 7) and TIMPs (n = 3) via immunodetection. We confirmed elevated levels of MMPs and TIMPs in GBM patients compared to meningiomas and astrocytomas. Even when correlating glioblastomas versus astrocytomas, we showed a significantly increased level of MMP1, MMP3, MMP13, and TIMP1. The identified metalloproteases may play a key role in the process of gliomagenesis and may represent potential targets for personalized therapy. However, as we have not confirmed the relationship between mRNA expression and protein levels in individual samples, it is therefore natural that the regulation of metalloproteases will be subject to several factors.

Hyperhomocysteinemia (HHcy) is considered an independent risk factor of cardiovascular diseases. Among the proposed mechanisms underlying homocysteine toxicity are altered protein expression and induction of oxidative stress. In the present study, we explored protein abundance and parameters related to oxidative stress in heart homogenates of rats exposed to chronic mild HHcy. Using two-dimensional gel electrophoresis followed by MALDI-TOF/TOF mass spectrometry 22 altered proteins (6 upregulated and 14 downregulated) were identified. For eight proteins the altered abundances were validated by Western blot analysis. Identified proteins are primarily involved in energy metabolism (mainly enzymes of glycolysis, pyruvate dehydrogenase complex, citric acid cycle, and ATP synthase), cardiac muscle contraction (alpha-actin and myosin light chains), stress response (heat-shock protein beta1 and alphaB-crystallin) and antioxidant defense (glutathione peroxidase 1). Diminished antioxidant defense was confirmed by decreases in total antioxidant capacity and GSH/GSSG ratio. Consistent with the decline in enzymatic and non-enzymatic antioxidant defense the protein oxidative modification, as determined by tyrosine nitration, was significantly increased. These findings suggest that both, altered protein expression and elevated oxidative stress contribute to cardiovascular injury caused by HHcy. Keywords: Homocysteine, Heart, Protein abundance, Antioxidant capacity, Nitrotyrosines.

BACKGROUND:Brain tumors are a heterogeneous group of malignancies characterized by inter- and intratumoral heterogeneity. Among them, the most aggressive and, despite advances in medicine, still incurable remains glioblastoma. One of the reasons is the high recurrence rate of the disease and resistance to temozolomide, a golden standard in chemotherapy of brain tumors. Therefore, mapping the pathways responsible for tumorigenesis at the transcriptional level may help to determine the causes and aggressive behavior among different glial tumors.PATIENTS AND METHODS:Biopsies from patients with astrocytoma (N = 6), glioblastoma (N = 22), and meningioma (N = 14) were included in the sample set. A control group consisted of RNA isolated from healthy human brain (N = 3). The reverse-transcribed cDNAs were analyzed using the Human Cancer PathwayFinder™ real-time PCR Array in a 96-well format. The expression of 84 genes belonging to 9 signaling pathways (angiogenesis, apoptosis, cell cycle and senescence, DNA damage and repair, epithelial-to-mesenchymal transition, hypoxia, overall metabolism, and telomere dynamics) was determined for each sample.RESULTS:By determining the relative expression of selected genes, we characterized the transcriptomic profile of individual brain malignancies in the context of signaling pathways involved in tumorigenesis. We observed deregulation in 50, 52.4 and 53.6% % of the genes in glioblastomas, meningiomas and astrocytomas, respectively. The most pronounced changes with statistical significance compared to control were observed in the genes associated with epithelial-to-mesenchymal transition (CDH2, FOXC2, GSC, SNAI2, and SOX10), cellular senescence (BMI1, ETS2, MAP2K1, and SOD1), DNA repair (DDB2, ERCC3, GADD45G, and LIG4), and dynamic of telomeres (TEP1, TERF2IP, TNKS, and TNKS2).CONCLUSION:Based on the obtained data, we can conclude that individual diagnoses differ in transcriptomic profile. An individual molecular approach is therefore necessary in order to provide comprehensive and targeted therapy on multiple metabolic pathways in the diagnosis of brain tumors.

The significant complexity of the brain can lead to the development of serious neuropsychiatric disorders, including schizophrenia. A number of mechanisms are involved in the etiopathogenesis of schizophrenia, pointing to its complexity and opening a new perspective on studying this disorder. In this review of currently published studies, we focused on the contribution of mitochondria to the process, with an emphasis on oxidative damage, ROS, and energy metabolism. In addition, we point out the influence of redox imbalance, which can lead to the occurrence of oxidative stress with increased lipid peroxidation, linked to the formation of toxic aldehydes such as 4-hydroxynonenal (4-HNE) and HNE protein adducts. We also analysed the role of lactate in the process of energy metabolism and cognitive functions in schizophrenia.

A brief period of transient global brain ischemia leads to selective ischemic neurodegeneration associated with death of hippocampal CA1 pyramidal neurons days after reperfusion. The mechanism of such selective and delayed neurodegeneration is still uncertain. Our work aimed to study the involvement of proteasomal and endoplasmic reticulum (ER) stress in ischemic neurodegeneration. We have performed laser scanning confocal microscopy analysis of brain slices from control and experimental animals that underwent global brain ischemia for 15 min and varying times of reperfusion. We have focused on ubiquitin, PUMA, a proapoptotic protein of the Bcl-2 family overexpressed in response to both proteasomal and ER stress, and p53, which controls expression of PUMA. We have also examined the expression of HRD1, an E3 ubiquitin ligase that was shown to be overexpressed after ER stress. We have also examined potential crosstalk between proteasomal and ER stress using cellular models of both proteasomal and ER stress. We demonstrate that global brain ischemia is associated with an appearance of distinct immunoreactivity of ubiquitin, PUMA and p53 in pyramidal neurons of the CA1 layer of the hippocampus 72 h after ischemic insults. Such changes correlate with a delay and selectivity of ischemic neurodegeneration. Immunoreactivity of HRD1 observed in all investigated regions of rat brain was transiently absent in both CA1 and CA3 pyramidal neurones 24 h after ischemia in the hippocampus , which does not correlate with a delay and selectivity of ischemic neurodegeneration. We do not document significant crosstalk between proteasomal and ER stress. Our results favour dysfunction of the ubiquitin proteasome system and consequent p53-induced expression of PUMA as the main mechanisms responsible for selective and delayed degeneration of pyramidal neurons of the hippocampal CA1 layer in response to global brain ischemia.

During aging, heart structure and function gradually deteriorate, which subsequently increases susceptibility to ischemia–reperfusion (IR). Maintenance of Ca2+ homeostasis is critical for cardiac contractility. We used Langendorff’s model to monitor the susceptibility of aging (6-, 15-, and 24-month-old) hearts to IR, with a specific focus on Ca2+-handling proteins. IR, but not aging itself, triggered left ventricular changes when the maximum rate of pressure development decreased in 24-month-olds, and the maximum rate of relaxation was most affected in 6-month-old hearts. Aging caused a deprivation of Ca2+-ATPase (SERCA2a), Na+/Ca2+ exchanger, mitochondrial Ca2+ uniporter, and ryanodine receptor contents. IR-induced damage to ryanodine receptor stimulates Ca2+ leakage in 6-month-old hearts and elevated phospholamban (PLN)-to-SERCA2a ratio can slow down Ca2+ reuptake seen at 2–5 μM Ca2+. Total and monomeric PLN mirrored the response of overexpressed SERCA2a after IR in 24-month-old hearts, resulting in stable Ca2+-ATPase activity. Upregulated PLN accelerated inhibition of Ca2+-ATPase activity at low free Ca2+ in 15-month-old after IR, and reduced SERCA2a content subsequently impairs the Ca2+-sequestering capacity. In conclusion, our study suggests that aging is associated with a significant decrease in the abundance and function of Ca2+-handling proteins. However, the IR-induced damage was not increased during aging.

Pyruvate carboxylase (PC) is an enzyme catalyzing the carboxylation of pyruvate to oxaloacetate. The enzymatic generation of oxaloacetate, an intermediate of the Krebs cycle, could provide the cancer cells with the additional anaplerotic capacity and promote their anabolic metabolism. Recent studies revealed that several types of cancer cells express PC. The gained anaplerotic capability of cells mediated by PC correlates with their expedited growth, higher aggressiveness, and increased metastatic potential. By immunohistochemical staining and immunoblotting analysis, we investigated PC expression among samples of different types of human brain tumors. Our results show that PC is expressed by the cells in glioblastoma, astrocytoma, oligodendroglioma, and meningioma tumors. The presence of PC in these tumors suppose that PC could support the anabolic metabolism of their cellular constituents by its anaplerotic capability.