Cytochrome C Oxidase Activity Research Articles

Late onset schizophrenia and delusional disorder: activity of platelet energy, glutamate, and glutathione metabolizing enzymes

IntroductionAlterations of glutamate, energy and glutathione metabolism contribute to the pathogenesis of psychotic disordersObjectivesRevealing clinical-biological correlations in patients with late onset schizophrenia and delusional disorder by determining clinical parameters and activity of platelet enzymes of energy, glutamate, and glutathione metabolism.Methods27 women of 45-80 years old were studied, with late onset schizophrenia or delusional disorder. Activity of platelet cytochrome c-oxidase (COX), glutamate dehydrogenase (GDH), glutathione reductase (GR) and glutathione-S-transferase (GST), and scores by PANSS, HAMD, MMSE, and CGI-S were evaluated twice: before and after the 28-th day of treatment. Activity of COX, GDH, GR, and GST was measured once in 23 women of 44-81 years old comprising the control group.ResultsAs compared with controls, only GDH activity was found significantly decreased (before and after treatment, p<0.001). Clusterisation of patients by enzymatic activities resulted in 3 clusters significantly different by COX, GDH and GST. Significant correlations were found between enzymatic activities and scores by psychometric scales: in the cluster 1 (n=9) baseline COX activity correlated with scores by PANSS positive subscale (R=0.9, p=0.001) and with scores by MMSE (R=-0.9, p=0.002); in the cluster 2 (n=12) GR activity after treatment negatively correlated with scores by PANSS (R=-0.9, p=0.001), PANSS negative subscale (R=-0.8, p=0.004), and CGI-S (R=-0.9, p=0.001).ConclusionsThe revealed correlations between enzymatic activities and clinical parameters give hope on detection of useful biochemical markers which, after enlargement of patients’ group with late onset psychotic disorders, would be validated for prediction of the pharmacotherapy efficiency and outcome of treatment.DisclosureNo significant relationships.

SsCox17, a copper chaperone, is required for pathogenic process and oxidative stress tolerance of Sclerotinia sclerotiorum

Stem rot, caused by Sclerotinia sclerotiorum has emerged as one of the major fungal pathogens of oilseed Brassica across the world. The pathogenic development is exquisitely dependent on reactive oxygen species (ROS) modulation. Cox17 is a crucial factor that shuttles copper ions from the cytosol to the mitochondria for the cytochrome c oxidase (CCO) assembly. Currently, no data is available regarding the impact of Cox17 in fungal pathogenesis. The present research was carried out to functionally characterize the role of Cox17 in S. sclerotiorum pathogenesis. SsCox17 transcripts showed high expression levels during inoculation on rapeseed. Intramitochondrial copper content and CCO activity were decreased in SsCox17 gene-silenced strains. The SsCox17 gene expression was up-regulated in the hyphae under oxidative stress and a deficiency response to oxidative stress was detected in SsCox17 gene-silenced strains. Compared to the S. sclerotiorum wild-type strain, there was a concomitant reduction in the virulence of SsCox17 gene-silenced strains. The SsCox17 overexpression strain was further found to increase copper content, CCO activity, tolerance to oxidative stress and virulence. We also observed a certain correlation of appressoria formation and SsCox17. These results provide evidence that SsCox17 is positively associated with fungal virulence and oxidative detoxification.

Dicer induced reactive oxygen species inhibit hepatocellular carcinoma through interacting with cytochrome c oxidase

Dicer is an RNaseIII in microRNA processing that modulates multiple biological processes including tumorigenesis. We have shown that Dicer could inhibit the growth of hepatocellular carcinoma (HCC) previously [Zhang L, Wang C, Liu S, Zhao Y, et al. Oncol Lett 2016;11:3961-3966]. Here, we evaluated the relationships between Dicer and reactive oxygen species (ROS) as well as their modulation for HCC. We found Dicer expression was positively associated with ROS generation in HCC tissue at borderline statistical levels (p = .065); functional analysis showed Dicer could both induce the ROS generation (p < .01) and reduce the activity of Cytochrome c Oxidase (COX) (p < .05) by comparing the Dicer transfected and control HCC cells. The COX inhibitor ADDA-5 hydrochloride could increase the ROS generation, whereas the ROS scavenger N-acetylcysteine (NAC) could decrease the COX activity. Further analysis also demonstrated that one kind of ROS, H2O2, could repress the proliferation and migration as well as increase the apoptosis of HCC cells. Our data indicated that Dicer could inhibit the HCC growth by promoting ROS generation; ROS and COX interacted with each other to modify this process.

Is Type 2 Diabetes a Primary Mitochondrial Disorder?

Diabetes mellitus is the most common endocrine disturbance in inherited mitochondrial diseases. It is essential to increase awareness of the correct diagnosis and treatment of diabetes in these patients and screen for the condition in family members, as diabetes might appear with distinctive clinical features, complications and at different ages of onset. The severity of mitochondrial-related diabetes is likely to manifest on a large scale of phenotypes depending on the location of the mutation and whether the number of affected mitochondria copies (heteroplasmy) reaches a critical threshold. Regarding diabetes treatment, the first-choice treatment for type 2 diabetes (T2D), metformin, is not recommended because of the risk of lactic acidosis. The preferred treatment for diabetes in patients with mitochondrial disorders is SGLT-2i and mitochondrial GLP-1-related substances. The tight relationship between mitochondrial dysfunction, reduced glucose-stimulated insulin secretion (GSIS), and diabetes development in human patients is acknowledged. However, despite the well-characterized role of mitochondria in GSIS, there is a relative lack of data in humans implicating mitochondrial dysfunction as a primary defect in T2D. Our recent studies have provided data supporting the significant role of the mitochondrial respiratory-chain enzyme, cytochrome c oxidase (COX), in regulating GSIS in a rodent model of T2D, the Cohen diabetic sensitive (CDs) rat. The nutritionally induced diabetic CDs rat demonstrates several features of mitochondrial diseases: markedly reduced COX activity in several tissues, increased reactive oxygen production, decreased ATP generation, and increased lactate dehydrogenase expression in islets. Moreover, our data demonstrate that reduced islet-COX activity precedes the onset of diabetes, suggesting that islet-COX deficiency is the primary defect causing diabetes in this model. This review examines the possibility of including T2D as a primary mitochondrial-related disease. Understanding the critical interdependence between diabetes and mitochondrial dysfunction, centering on the role of COX, may open novel avenues to diagnose and treat diabetes in patients with mitochondrial diseases and mitochondrial dysfunction in diabetic patients.

No Effects of Photobiomodulation on Prefrontal Cortex and Hippocampal Cytochrome C Oxidase Activity and Expression of c-Fos Protein of Young Male and Female Rats.

The role of light in our biological processes and systems is extensively known. In addition, the use of light devices has been introduced in the field of healthcare as an opportunity to administer power light at specific wavelengths to improve our body functions and counteract light deficiency. One of these techniques is photobiomodulation (PBM), which uses red to infrared light in a non-invasive way to stimulate, heal, regenerate, and protect tissue. The main proposed mechanism of action is the stimulation of the cytochrome c oxidase (CCO), the terminal enzyme in the mitochondrial electron transport chain. PBM has achieved positive effects on brain activity and behavioral function of several adult animal models of health and disease, the potential use of this technique in developing stages is not surprising. This research aims to examine the effects of PBM on the prefrontal cortex and hippocampus of 23 day-old healthy male (n = 31) and female (n = 30) Wistar rats. Three groups of each sex were used: a PBM group which received 5 days of PBM, a device group submitted to the same conditions but without light radiation, and a control basal group. CCO histochemistry and c-Fos immunostaining were used to analyze brain metabolic activity and immediate early genes activation, respectively. Results displayed no metabolic differences between the three groups in both sexes. The same results were found in the analysis of c-Fos positive cells, reporting no differences between groups. This research, in contrast to the PBM consequences reported in healthy adult subjects, showed a lack of PBM effects in the brain markers we examined in young healthy rat brains. At this stage, brain function, specifically brain mitochondrial function, is not disturbed so it could be that the action of PBM in the mitochondria may not be detectable using the analysis of CCO activity and c-Fos protein expression. Further studies are needed to examine in depth the effects of PBM in brain development, cognitive functions and postnatal disorders, along with the exploration of the optimal light parameters.

MO438: Excessive Mitochondrial Copper Load Driven by Upregulated Copper Transporter 1 Contributes to Mitochondrial Dysfunction and Renal Fibrosis

Abstract BACKGROUND AND AIMS Copper is an essential trace element for eukaryotes and a vital cofactor for various enzymes for a multiplicity of functions. Our previous study indicated that intracellular copper overload plays an important role in renal fibrosis. However, the underlying mechanism invoked by copper overload in renal fibrosis remains largely unknown. In this study, we found copper ions in cells were mainly accumulated in mitochondria, which damage the structure and function of mitochondria. Furthermore, copper transporter 1 (CTR1), the major transporter for the copper influx, was significantly increased in fibrotic kidneys. The activity of cytochrome C oxidase (COX), a copper coenzyme mediating the final step in the electron transport chain, was decreased. Therefore, we proposed that CTR1 might be involved in mitochondrial copper overload and renal fibrosis. METHOD The expression of CTR1 was examined in ischemia-reperfusion injury (IRI 28d) mice model. The regulatory mechanisms of CTR1 in vitro were investigated by treating renal tubule epithelium cell line (NRK-52E) with TGF-β1 or copper ions with or without copper chelator tetrathiomolybdate (TM) and in vivo, we use CTR1 transgenic mice subjected to IRI operation. ICP-MS, mitoSOX Red, electron microscopy, realtime-PCR and western blot analysis were applied in the current study. RESULTS We found that stimulated by TGF-β1, COX activity was declined. Mitochondria and cytosol, especially mitochondria, accumulated a large amount of copper in fibrotic kidney tissues. Furthermore, we found Copper transporter 1 (CTR1) expression was increased in fibrotic kidneys from chronic kidney disease patients, experimental fibrosis model mice and in vitro. More importantly, compared with WT mice, CTR1+/- mice subjected to an ischemia-reperfusion injury (IRI) had reduced mitochondrial copper level and ameliorated mitochondrial function and renal fibrosis, as evidenced by improving mitochondrial structure, inhibiting mtROS production and reducing expression of α-smooth muscle actin (α-SMA), collagen I and fibronectin. In addition, after treatment with the copper chelator tetrathiomolybdate (TM), mitochondrial function and kidney fibrosis were improved. CONCLUSION Collectively, our study showed that copper overload in mitochondria could damage the mitochondrial function and lead to renal fibrosis and CTR1 is involved in the mitochondrial copper overload. Copper overload inhibits the activity of COX and impairs mitochondria, subsequently leading to renal fibrosis.

Heat Stress More Negatively Impacts Cardiac Muscle Mitochondria in Female Versus Male Pigs

With continued trends toward more frequent and more severe heat events there is a greater risk of environment‐induced heat stress (HS). How persistently elevated core temperatures impacts body tissues remains largely unknown. Our preliminary evidence indicates HS may negatively impact cardiac tissue and that biological sex may play a role in HS‐mediated pathology. To further test the hypothesis that cardiac muscle mitochondria are more negatively impacted by HS in females than in males, samples were isolated from the left ventricle (LV) of the heart from 3‐month‐old castrated male and prepubertal female pigs that were exposed to thermoneutral (TN) conditions (n = 4 per sex) or HS conditions for 24 h at 37°C (HS; n = 6 per sex). Samples were analyzed for citrate synthase (CS) and cytochrome c oxidase (COX) activities, and for mitochondrial oxidative phosphorylation (P) and electron transfer (E) capacities via high resolution respirometry. Data were analyzed by mixed linear models in SAS v9.4 with treatment, sex, and treatment × sex as fixed effects. A traditional marker of mitochondrial volume density, CS activity, tended to be greater in TN males compared to HS males (P = 0.08) but was unaffected by HS in female pigs. Conversely, intrinsic (relative to CS activity) mitochondrial function, as measured by COX activity, was greater in TN females than HS females (P = 0.04) and within HS, males maintained greater intrinsic mitochondrial function than females (P = 0.02). Both integrative (relative to tissue wet weight) and intrinsic mitochondrial leak respiration were greater in HS than TN pigs (P = 0.03) but the contribution of leak to total E (flux control ratio; FCRLEAK) tended to be greater in males than females (P = 0.07). Conversely, both integrative and intrinsic maximal E (ECI+II) tended to be greater in female than male pigs (P = 0.08) indicating a greater degree of excess electron transfer capacity in females. The contribution of complex I‐supported P (PCI) to total E (FCRPCI) tended to be greater in TN compared to HS pigs regardless of sex (P = 0.09) and the contribution of maximal P to E (FCRPCI+II) was greater in TN females compared to HS females (P = 0.05). This resulted in the FCRPCI+IIbeing greater in males compared to females in the HS condition (P = 0.01), suggesting greater coupling of oxidative phosphorylation and electron transfer in cardiac mitochondria in males during 24 h of HS. These results suggest that HS may negatively impact cardiac muscle mitochondria in female pigs compared to males. Moreover, these data indicate that persistent HS has deleterious consequences for the myocardium and may represent an additional health concern caused by global climate trends. This project was supported by USDA NIFA Award #2020‐68014‐31954.

Cytochrome c oxidase mediates labile iron level and radioresistance in glioblastoma

Radiotherapy is an important treatment modality for glioblastoma (GBM), yet the initial effectiveness of radiotherapy is eventually lost due to the development of adaptive radioresistance during fractionated radiation therapy. Defining the molecular mechanism(s) responsible for the adaptive radioresistance in GBM is necessary for the development of effective treatment options. The cellular labile iron pool (LIP) is very important for determining the cellular response to radiation, as it contributes to radiation-induced production of reactive oxygen species (ROS) such as lipid radicals through Fenton reactions. Recently, cytochrome c oxidase (CcO), a mitochondrial heme-containing enzyme also involved in regulating ROS production, was found to be involved in GBM chemoresistance. However, the role of LIP and CcO in GBM radioresistance is not known. Herein, we tested the hypothesis that CcO-mediated alterations in the level of labile iron contribute to adaptive radioresistance. Using an in vitro model of GBM adaptive radioresistance, we found an increase in CcO activity in radioresistant cells that associated with a decrease in the cellular LIP, decrease in lipid peroxidation, and a switch in the CcO subunit 4 (COX4) isoform expressed, from COX4-2 to COX4-1. Furthermore, knockdown of COX4-1 in radioresistant GBM cells decreased CcO activity and restored radiosensitivity, whereas overexpression of COX4-1 in radiosensitive cells increased CcO activity and rendered the cells radioresistant. Overexpression of COX4-1 in radiosensitive cells also significantly reduced the cellular LIP and lipid peroxidation. Pharmacological manipulation of the cellular labile iron level using iron chelators altered CcO activity and the radiation response. Overall, these results demonstrate a mechanistic link between CcO activity and LIP in GBM radioresistance and identify the CcO subunit isoform switch from COX4-2 to COX4-1 as a novel biochemical node for adaptive radioresistance of GBM. Manipulation of CcO and the LIP may restore the sensitivity to radiation in radioresistant GBM cells and thereby provide a strategy to improve therapeutic outcome in patients with GBM.

Hypothermal Effects on Energy Supply for Ionocytes in Gills of Freshwater- and Seawater-Acclimated Milkfish, Chanos chanos

The milkfish, Chanos chanos, is an important aquaculture species that can be cultured in freshwater (FW) and seawater (SW) ponds because of its high euryhalinity. In winter, cold snap leading to high mortality of this tropical species is a critical issue for the aquaculture industry in Taiwan. Under hypothermal stress, however, changes in energy supply for osmoregulation of this euryhaline species is intriguing. In this study, we used an antibody against glycogen phosphorylase (GP) to identify glycogen-rich (GR) cells distributed adjacent to the mitochondria-rich (MR) ionocytes in milkfish gills. Glucose transporter 1 (GLUT1), which plays a major role in energy supply, was also identified and localized in GR cells. Moreover, the expression of indicators of aerobic metabolism and energy production, citrate synthase (CS) and cytochrome c oxidase (COX), were analyzed in gills of FW- and SW-acclimated milkfish to reveal different strategies of energy utilization under hypothermal stress. When exposed to a low-temperature environment, SW individuals used branchial glycogen and lactate to match the energy demands of aerobic metabolism in ionocytes, and elevated aerobic capacity to support and maintain normal functions in gills. However, branchial glycogen mainly localized in the GR cells of FW milkfish was not utilized under hypothermal stress. Meanwhile, a similar level of branchial COX activity and COXIV protein abundance at low temperatures between FW and SW milkfish indicated similar energy requirements in gills. This suggested that another source, but not branchial glycogen, maintained the energy demand in FW milkfish. The present study illustrated differential energy supply strategies in gills between SW- and FW-acclimated milkfish for osmoregulation under low temperatures.

МЕХАНИЗМЫ МИТОХОНДРИАЛЬНОЙ ДИСФУНКЦИИ НЕЙРОНОВ ПРИ ВОЗДЕЙСТВИИ МЫШЬЯКА И АЛЮМИНИЯ (ОБЗОР)

Exposure to neurotropic chemicals (aluminum, arsenic, etc.) as a result of pollution of environmental objects can cause disruption of the bioenergetics of nerve cells. Objectives. To analyze and summarize the literature data on the mechanisms of the effects of arsenic and aluminum on the structure and functions of neuronal mitochondria. Sources of data: literature sources reflecting the mechanisms of the influence of these neurotoxicants on neuronal mitochondria. Methods. The basis of this study was the review of literature on this topic. Results. The influence of arsenic compounds on nerve cells causes mitochondrial dysfunction due to the activation of oxidative stress, an increase in the intracellular level of Ca&lt;sup&gt;2+&lt;/sup&gt;, a decrease in the mitochondrial membrane potential and the level of calpain 1, but aluminum compounds increase the formation of reactive oxygen species (ROS) and disrupt the activity of cytochrome c-oxidase and the energy-producing function of mitochondria in various types of neurons. Mitochondrial dysfunction, caused when exposed to these metals is accompanied by the decrease in ROS resynthesis and the activation of oxidative stress, which in its turn decreases energy generation in mitochondria still to a greater extent according to the mechanism of a vicious circle («CIRCULUS VITIOSUS»). Conclusions. The presented information deepens our knowledge about the mechanisms of neuronal bioenergetics disorders under the influence of arsenic and aluminum compounds, which is the basis for further research in order to develop effective methods of prevention, detoxification and antioxidant therapy for acute and chronic arsenic and aluminum poisoning and to implement the results obtained in practical healthcare.

Photobiomodulation of Cytochrome c Oxidase by Chronic Transcranial Laser in Young and Aged Brains

In cellular bioenergetics, cytochrome c oxidase (CCO) is the enzyme responsible for oxygen consumption in the mitochondrial electron transport chain, which drives oxidative phosphorylation for adenosine triphosphate (ATP) production. CCO is also the major intracellular acceptor of photons in the light wavelengths used for photobiomodulation (PBM). Brain function is critically dependent on oxygen consumption by CCO for ATP production. Therefore, our objectives were (1) to conduct the first detailed brain mapping study of the effects of PBM on regional CCO activity, and (2) to compare the chronic effects of PBM on young and aged brains. Specifically, we used quantitative CCO histochemistry to map the differences in CCO activity of brain regions in healthy young (4 months old) and aged (20 months old) rats from control groups with sham stimulation and from treated groups with 58 consecutive days of transcranial laser PBM (810 nm wavelength and 100 mW power). We found that aging predominantly decreased regional brain CCO activity and systems-level functional connectivity, while the chronic laser stimulation predominantly reversed these age-related effects. We concluded that chronic PBM modified the effects of aging by causing the CCO activity on brain regions in laser-treated aged rats to reach levels similar to those found in young rats. Given the crucial role of CCO in bioenergetics, PBM may be used to augment brain and behavioral functions of older individuals by improving oxidative energy metabolism.

Cytochrome c Oxidase Activity as a Metabolic Regulator in Pancreatic Beta-Cells.

Pancreatic β-cells couple glucose-stimulated insulin secretion (GSIS) with oxidative phosphorylation via cytochrome c oxidase (COX), a mitochondrial respiratory-chain enzyme. The Cohen diabetic-sensitive (CDs) rats exhibit hyperglycemia when fed a diabetogenic diet but maintain normoglycemia on a regular diet. We have previously reported a decreased COX activity in CDs rats and explored its relevance for type 2 diabetes (T2D). In this study, we investigated the relation between COX activity in islets, peripheral-blood mononuclear cells (PBMCs), and GSIS during diabetes development in CDs rats fed a diabetogenic diet for 4, 11, 20, and 30 days and during reversion to normoglycemia in hyperglycemic CDs rats fed a reversion diet for 7, 11, and 20 days. An oral glucose-tolerance test was performed at different periods of the diets measuring blood glucose and insulin concentrations. COX activity was determined in islets and PBMCs isolated from rats at the different periods of the diets. We demonstrated a progressive reduction in COX activity in CDs-islets that correlated positively with the decreasing GSIS (R2 = 0.9691, p < 0.001) and inversely with the elevation in blood glucose levels (R2 = 0.8396, p < 0.001). Hyperglycemia was initiated when islet COX activity decreased below 46%. The reversion diet restored >46% of the islet COX activity and GSIS while re-establishing normoglycemia. Interestingly, COX activity in PBMCs correlated significantly with islet COX activity (R2 = 0.8944, p < 0.001). Our data support islet COX activity as a major metabolic regulator of β-cells function. The correlation between COX activity in PBMCs and islets may serve as a noninvasive biomarker to monitor β-cell dysfunction in diabetes.

Direct Interaction of Mitochondrial Cytochrome c Oxidase with Thyroid Hormones: Evidence for Two Binding Sites.

Thyroid hormones regulate tissue metabolism to establish an energy balance in the cell, in particular, by affecting oxidative phosphorylation. Their long-term impact is mainly associated with changes in gene expression, while the short-term effects may differ in their mechanisms. Our work was devoted to studying the short-term effects of hormones T2, T3 and T4 on mitochondrial cytochrome c oxidase (CcO) mediated by direct contact with the enzyme. The data obtained indicate the existence of two separate sites of CcO interaction with thyroid hormones, differing in their location, affinity and specificity to hormone binding. First, we show that T3 and T4 but not T2 inhibit the oxidase activity of CcO in solution and on membrane preparations with Ki ≈ 100–200 μM. In solution, T3 and T4 compete in a 1:1 ratio with the detergent dodecyl-maltoside to bind to the enzyme. The peroxidase and catalase partial activities of CcO are not sensitive to hormones, but electron transfer from heme a to the oxidized binuclear center is affected. We believe that T3 and T4 could be ligands of the bile acid-binding site found in the 3D structure of CcO by Ferguson-Miller’s group, and hormone-induced inhibition is associated with dysfunction of the K-proton channel. A possible role of this interaction in the physiological regulation of the enzyme is discussed. Second, we find that T2, T3, and T4 inhibit superoxide generation by oxidized CcO in the presence of excess H2O2. Inhibition is characterized by Ki values of 0.3–5 μM and apparently affects the formation of O2●− at the protein surface. The second binding site for thyroid hormones presumably coincides with the point of tight T2 binding on the Va subunit described in the literature.

Morphological and physiological correlates of among- individual variation in basal metabolic rate in two passerine birds

Basal metabolic rate (BMR) has been shown to be a highly phenotypic flexibility trait within species. A significant proportion of an individual's energy budget is accounted for by BMR, hence among-individual variation in this trait may affect other energetic processes, as well as fitness. In this study, we measured BMR, organ mass, mitochondrial respiration capacities and cytochrome c oxidase (COX) activities in muscle and liver and circulating levels of plasma triiodothyronine (T3) in Chinese bulbuls (Pycnonotus sinensis) and Eurasian tree sparrows (Passer montanus). Our results showed that heart and kidney mass was positively correlated with BMR in Chinese bulbuls, whereas liver and kidney mass was positively correlated with BMR in Eurasian tree sparrows. Regarding metabolic biochemical markers of tissues, state 4 respiration and COX activity in the muscles of the Chinese bulbuls was correlated with BMR, while state 4 respiration in the muscle and liver was correlated with BMR in Eurasian tree sparrows. T3 was significantly and positively correlated with BMR in Chinese bulbuls and Eurasian tree sparrows. Consistent with the above results, our findings suggest that T3 levels play an important role in modulating BMR in Chinese bulbuls and Eurasian tree sparrows. Moreover, individual variation in BMR can be explained partly by morphological and physiological mechanisms.

Seasonal changes in mitochondrial bioenergetics and physiological performance of the bluegill sunfish, Lepomis macrochirus, from a shallow, Midwest river.

As global temperature shifts due to anthropogenic impacts, seasonal temperatures in shallow aquatic ecosystems are expected to increase. Previous studies on freshwater fishes that experience significant temperature changes during the annual seasons found pronounced physiological restructuring not observed in animals inhabiting more thermally stable environments. Studies evaluating mitochondrial bioenergetics in fish are often performed on animals acclimated to constant temperatures in the laboratory. However, natural habitats are much more complex. Fishes may experience substantial daily and seasonal variation in temperature, energy requirements and resource availability, which are impossible to emulate on acclimation studies. Our study explores the effects of these more complex natural environments on whole-organism thermal tolerance and mitochondrial bioenergetics in bluegill sunfish (Lepomis macrochirus), a native fish to the temperate zone of North America. Compensatory mechanisms and variations in physiological thresholds were observed in specimens acclimatized to the fall season compared to specimens acclimatized to spring and summer seasons. Somatic indices, such as relative weights and hepatosomatic indices, showed significant differences across seasons and critical thermal maxima significantly decreased in the cold acclimatized specimens. Liver mitochondria from L. macrochirus also showed significantly higher uncoupled proton conductance, cytochrome c oxidase (COX) activity, and reduced respiratory control ratios in individuals sampled in the colder season. These findings suggest that mechanisms regulating proton conductance and COX activity modulate mitochondrial function across seasons to sustain physiological fitness in ectotherms inhabiting shallow, inland aquatic habitats.

New approaches to the typology and prediction of the effectiveness of therapy for late-life depression

To analyze clinical parameters and effectiveness of therapy in depressed patients of late age with different activity of enzymes of energy, glutamate metabolism and antioxidant glutathione system in platelets and red blood cells. The study included 53 hospitalized patients (41 women and 12 men), aged 60 to 86 years (median - 66 years), with a depressive episode of mild to marked severity within the framework of recurrent depressive disorder, bipolar affective disorder or a single depressive episode according to ICD-10. The patients were examined using clinical, psychometric, biochemical and statistical methods. Psychometric assessment of patients' condition was performed before the start of therapy and on the 28th day of treatment using HAMD-17 and HARS. Blood sampling was carried out to determine the activity of cytochrome c-oxidase (COX), glutathione reductase (GR), glutathione S-transferase (GST) and glutamate dehydrogenase (GDH). Cluster analysis revealed 3 clusters (Cl.1, Cl.2, Cl.3), which differed in biochemical indicators. In Cl.1 (n=24, 45.2%), there was a decrease in the activity of COX (p<0.05) and a decrease of GR activity in red blood cells and GST activity in platelets (p<0.001). Patients of Cl.2 (n=11, 20.8%) had increased COX activity (p<0.001) and decreased GDH activity (p<0.001). In patients of Cl.3 (n=18, 34%) the enzyme activity was similar to that in the controls. Later age at disease onset was observed in Cl.1 compared to Cl.2 (51 years [40; 60.5] and 32 years [19; 59], p=0.052). Compared with Cl.2 and Cl.3, patients of Cl.1 significantly more often (p<0.05) had apathetic depressions (41.7%), while complex depressions were observed almost 2 times less often than in Cl.2 (50% and 91.9%, p<0.05). The effectiveness and tolerability of psychopharmacotherapy was higher in Cl.3. There is a relationship between the nature of changes in metabolic parameters and differences in the phenomenology and course of late-age depression. The results of the study open up new directions in the field of predicting the effectiveness of therapy and the development of personalized therapeutic approaches to improve the effectiveness and safety of treatment of depressed elderly patients.

Chemical composition and actoprotective activity of extracts from the grass Lysimachia punctata L. (Verbena Pointness)

An important task of modern pharmacology and medical chemistry is to expand the range of effective and safe medicines. In this regard, the scientific community is paying more and more attention to objects of plant origin. The aim of the study was to study the chemical composition of the extraction of verbena pointness grass and to evaluate its actoprotective activity. The total content of flavonoids was determined by the spectrophotometric method. The amino acid and trace element composition in the extraction of verbena pointness grass was determined by capillary electrophoresis. The actoroprotective activity of the extraction of verbena pointness grass was evaluated on male mice of the Balb/c line in the forced swimming with load test. The effect of the studied extraction on the change in the activity of succinate dehydrogenase and cytochrome-c oxidase in muscle tissue was also determined. During the study, it was found that 12 free amino acids were found in the analyzed extract, of which 6 are essential (arginine, β-phenylalanine, leucine, methionine, threonine, valine), with a flavonoid content from 0.57% to 0.60%. The analyzed extraction is quantitatively dominated by potassium among trace elements. The use of the studied extract increased the level of efficiency of animals by 156.6% (p&lt;0.05) with an increase in the activity of cytochrome-c-oxidase and succinate dehydrogenase by 40.5% (p&lt;0.05) and 61.5% (p&lt;0.05), respectively. Thus, it was found that the extraction of verbena pointness grass is characterized by a rich chemical composition and the presence of actoprotective potential, which makes it a promising object for further study.

Prospective biomarker study in newly diagnosed glioblastoma: Cyto-C clinical trial.

BackgroundGlioblastoma (GBM) has a 5-year survival rate of 3%-5%. GBM treatment includes maximal resection followed by radiotherapy with concomitant and adjuvant temozolomide (TMZ). Cytochrome C oxidase (CcO) is a mitochondrial enzyme involved in the mechanism of resistance to TMZ. In a prior retrospective trial, CcO activity in GBMs inversely correlated with clinical outcome. The current Cyto-C study was designed to prospectively evaluate and validate the prognostic value of tumor CcO activity in patients with newly diagnosed primary GBM, and compared to the known prognostic value of MGMT promoter methylation status.MethodsThis multi-institutional, blinded, prospective biomarker study enrolled 152 patients with newly diagnosed GBM who were to undergo surgical resection and would be candidates for standard of care. The primary end point was overall survival (OS) time, and the secondary end point was progression-free survival (PFS) time. Tumor CcO activity and MGMT promoter methylation status were assayed in a centralized laboratory.ResultsOS and PFS did not differ by high or low tumor CcO activity, and the prognostic validity of MGMT promoter methylation was confirmed. Notably, a planned exploratory analysis suggested that the combination of low CcO activity and MGMT promoter methylation in tumors may be predictive of long-term survival.ConclusionsTumor CcO activity alone was not confirmed as a prognostic marker in GBM patients. However, the combination of low CcO activity and methylated MGMT promoter may reveal a subgroup of GBM patients with improved long-term survival that warrants further evaluation. Our work also demonstrates the importance of performing large, multi-institutional, prospective studies to validate biomarkers. We also discuss lessons learned in assembling such studies.

The use of antioxidant medicine as an adjunctive therapy in late-onset schizophrenia spectrum disorders

BACKGROUND. Imbalance in the activity of neurotransmitter systems, mitochondrial impairment, and oxidative stress are potential neurobiological factors in the schizophrenia development.&#x0D; AIM. To test the hypothesis about the possibility of a subgroup selection from patients with late-onset schizophrenia spectrum disorders, for which the use of ethylmethylhydroxypyridine succinate as an adjunctive to antipsychotic therapy would be the most effective in relation to symptoms that are relatively more pronounced in patients of this subgroup.&#x0D; MATERIAL AND METHODS. 43 patients (women and men) aged 4578 years with late-onset (after 40 years) schizophrenia spectrum disorders were examined using clinical psychopathological, psychometric, biochemical and statistical research methods. Enzymatic activities of cytochrome C-oxidase, glutamate dehydrogenase, glutathione reductase and glutathione-S-transferase were assessed in blood cells twice (on a patient admission to the hospital and after a 28-day treatment course).&#x0D; RESULTS. Criteria for a patient assignment to the subgroup for ethylmethylhydroxypyridine succinate prescription were: more prominent side effects of pharmacotherapy, predominance of anxiety-hypochondriac symptoms and a lesser severity of psychosis. Before the treatment starting, the subgroup to which ethylmethylhydroxypyridine succinate was prescribed significantly differed in the activity of platelet glutamate dehydrogenase (p=0.031), glutathione-S-transferase (p=0.005), and erythrocyte glutathione reductase (p=0.045). As a result of the treatment course, the severity of symptoms by which the patients receiving ethylmethylhydroxypyridine succinate significantly differed before the starting the treatment, became undistinguished from those in the rest examined patients. After the treatment course, no significant differences in enzymatic activities were found in patients treated with ethylmethylhydroxypyridine succinate from those in other patients.&#x0D; CONCLUSION. This study confirmed the clinical validity of using a medicine with antioxidant properties as an adjunctive therapy to the main treatment in the selected subgroup of patients.

Hippocampal neuropeptide Y2 receptor blockade improves spatial memory retrieval and modulates limbic brain metabolism

IntroductionThe neuropeptide Y (NPY) is broadly distributed in the central nervous system (CNS), and it has been related to neuroprotective functions. NPY seems to be an important component to counteract brain damage and cognitive impairment mediated by drugs of abuse and neurodegenerative diseases, and both NPY and its Y2 receptor (Y2R) are highly expressed in the hippocampus, critical for learning and memory. We have recently demonstrated its influence on cognitive functions; however, the specific mechanism and involved brain regions where NPY modulates spatial memory by acting on Y2R remain unclear. MethodsHere, we examined the involvement of the hippocampal NPY Y2R in spatial memory and associated changes in brain metabolism by bilateral administration of the selective antagonist BIIE0246 into the rat dorsal hippocampus. To further evaluate the relationship between memory functions and neuronal activity, we analysed the regional expression of the mitochondrial enzyme cytochrome c oxidase (CCO) as an index of oxidative metabolic capacity in limbic and non-limbic brain regions. ResultsThe acute blockade of NPY Y2R significantly improved spatial memory recall in rats trained in the Morris water maze that matched metabolic activity changes in spatial memory processing regions. Specifically, CCO activity changes were found in the dentate gyrus of the dorsal hippocampus and CA1 subfield of the ventral hippocampus, the infralimbic region of the PFC and the mammillary bodies. ConclusionsThese findings suggest that the NPY hippocampal system, through its Y2R receptor, influences spatial memory recall (retrieval) and exerts control over patterns of brain activation that are relevant for associative learning, probably mediated by Y2R modulation of long-term potentiation and long-term depression.