Oxidative Energy Metabolism Research Articles

Metabolic and oxidative status alterations induced in Ruditapes philippinarum exposed chronically to estrogen 17α-ethinylestradiol under a warming scenario.

The presence of pharmaceuticals in the aquatic environment is an ongoing concern. However, the information regarding their effects under different climate change scenarios is still scarce. 17α-ethinylestradiol (EE2) is widely present in different aquatic systems showing negative impacts on aquatic organisms even when present at trace concentrations (≈1ng/L). Nevertheless, its impact on bivalves is poorly understood, especially considering the influence of climate change factors. This study aimed to assess the toxicological impacts of EE2 under current and predicted warming scenarios, in the edible clam Ruditapes philippinarum. For this, clams were exposed for 28 days to different EE2 concentrations (5, 25, 125, 625ng/L), under two temperatures (17 °C (control) and 21 °C). Drug concentrations, bioconcentration factors and biochemical parameters, related to oxidative stress and energy metabolism, were evaluated. Results showed that under actual and predicted temperature scenarios EE2 concentrations led to a disturbance in redox homeostasis of the clams, characterized by an increase in oxidized glutathione in contaminated organisms compared to control ones. Nevertheless, clams were capable to cope with the stressful conditions, activating their defence mechanisms (especially at the highest exposure concentration and in particular at increased temperature), and no oxidative damage occured. Although limited effects were observed, the present findings indicate that under both temperatures contaminated clams altered their biochemical performance, which can impair their sensitivity and protection capacity to respond to other environmental changes and/or affect their capacity to grow and reproduce. The results presented here highlight the need for further research on this thematic, considering that climate change is an ongoing problem, and the levels of some pharmaceutical drugs will continue to increase in marine/estuarine environments.

Induction of Synthetic Lethality by Activation of Mitochondrial ClpP and Inhibition of HDAC1/2 in Glioblastoma.

Novel therapeutic targets are critical to unravel for the most common primary brain tumor in adults, glioblastoma (GBM). We have identified a novel synthetic lethal interaction between ClpP activation and HDAC1/2 inhibition that converges on GBM energy metabolism. Transcriptome, metabolite, and U-13C-glucose tracing analyses were utilized in patient-derived xenograft (PDX) models of GBM. Orthotopic GBM models were used for in vivo studies. We showed that activation of the mitochondrial ClpP protease by mutant ClpP (Y118A) or through utilization of second-generation imipridone compounds (ONC206 and ONC212) in combination with genetic interference of HDAC1 and HDAC2 as well as with global (panobinostat) or selective (romidepsin) HDAC inhibitors caused synergistic reduction of viability in GBM model systems, which was mediated by interference with tricarboxylic acid cycle activity and GBM cell respiration. This effect was partially mediated by activation of apoptosis along with activation of caspases regulated chiefly by Bcl-xL and Mcl-1. Knockdown of the ClpP protease or ectopic expression of a ClpP D190A mutant substantially rescued from the inhibition of oxidative energy metabolism as well as from the reduction of cellular viability by ClpP activators and the combination treatment, respectively. Finally, utilizing GBM PDX models, we demonstrated that the combination treatment of HDAC inhibitors and imipridones prolonged host survival more potently than single treatments or vehicle in vivo. Collectively, these observations suggest that the efficacy of HDAC inhibitors might be significantly enhanced through ClpP activators in model systems of human GBM.

Edaravone ameliorates depressive and anxiety-like behaviors via Sirt1/Nrf2/HO-1/Gpx4 pathway

BackgroundThe inflammation and oxidative stress (OS) have been considered crucial components of the pathogenesis of depression. Edaravone (EDA), a free radical scavenger, processes strong biological activities including antioxidant, anti-inflammatory and neuroprotective properties. However, its role and potential molecular mechanisms in depression remain unclear. The present study aimed to investigate the antidepressant activity of EDA and its underlying mechanisms.MethodsA chronic social defeat stress (CSDS) depression model was performed to explore whether EDA could produce antidepressant effects. Behaviors tests were carried out to examine depressive, anxiety-like and cognitive behaviors including social interaction (SI) test, sucrose preference test (SPT), open field test (OFT), elevated plus maze (EPM), novel object recognition (NOR), tail suspension test (TST) and forced swim test (FST). Hippocampal and medial prefrontal cortex (mPFC) tissues were collected for Nissl staining, immunofluorescence, targeted energy metabolomics analysis, enzyme-linked immunosorbent assay (ELISA), measurement of MDA, SOD, GSH, GSH-PX, T-AOC and transmission electron microscopy (TEM). Western blotting (WB) and quantitative real-time polymerase chain reaction (qRT-PCR) detected the Sirt1/Nrf2/HO-1/Gpx4 signaling pathway. EX527, a Sirt1 inhibitor and ML385, a Nrf2 inhibitor were injected intraperitoneally 30 min before EDA injection daily. Knockdown experiments were performed to determine the effects of Gpx4 on CSDS mice with EDA treatment by an adeno-associated virus (AAV) vector containing miRNAi (Gpx4)–EGFP infusion.ResultsThe administrated of EDA dramatically ameliorated CSDS-induced depressive and anxiety-like behaviors. In addition, EDA notably attenuated neuronal loss, microglial activation, astrocyte dysfunction, oxidative stress damage, energy metabolism and pro-inflammatory cytokines activation in the hippocampus (Hip) and mPFC of CSDS-induced mice. Further examination indicated that the application of EDA after the CSDS model significantly increased the protein expressions of Sirt1, Nrf2, HO-1 and Gpx4 in the Hip. EX527 abolished the antidepressant effect of EDA as well as the protein levels of Nrf2, HO-1 and Gpx4. Similarly, ML385 reversed the antidepressant and anxiolytic effects of EDA via decreased expressions of HO-1 and Gpx4. In addition, Gpx4 knockdown in CSDS mice abolished EDA-generated efficacy on depressive and anxiety-like behaviors.ConclusionThese findings suggest that EDA possesses potent antidepressant and anxiolytic properties through Sirt1/Nrf2/HO-1/Gpx4 axis and Gpx4-mediated ferroptosis may play a key role in this effect.

Metabolic determination of cell fate through selective inheritance of mitochondria.

Metabolic characteristics of adult stem cells are distinct from their differentiated progeny, and cellular metabolism is emerging as a potential driver of cell fate conversions 1–4 . How these metabolic features are established remains unclear. Here, we identified inherited metabolism imposed by functionally distinct mitochondrial age-classes as a fate determinant in asymmetric division of epithelial stem-like cells. While chronologically old mitochondria support oxidative respiration, the electron transport chain of the new organelles is proteomically immature and they respire less. Upon cell division, selectively segregated mitochondrial age-classes elicit a metabolic bias in progeny cells, with oxidative energy metabolism promoting differentiation in cells inheriting old mitochondria. Cells inheriting newly synthesised mitochondria with low levels of Rieske iron-sulfur polypeptide 1 have a higher pentose phosphate pathway activity, which promotes de-novo purine biosynthesis and redox balance, and is required to maintain stemness during early fate determination after division. Our results demonstrate that fate decisions are susceptible to intrinsic metabolic bias imposed by selectively inherited mitochondria.

Integrative Metabolomics, Proteomics and Transcriptomics Analysis Reveals Liver Toxicity of Mesoporous Silica Nanoparticles.

As pharmaceutical excipients, mesoporous silica nanoparticles (MSNs) have attracted considerable concern based on potential risks to the public. The impact of MSNs on biochemical metabolism is poorly understood, and few studies have compared the effects of MSNs administered via different routes. To evaluate the hepatotoxicity of MSNs, metabolomics, proteomics and transcriptomic analyses were performed in mice after intravenous (20 mg/kg/d) or oral ad-ministration (200 mg/kg/d) of MSNs for 10 days. Intravenous injection induced significant hepatic injury based on pathological inspection and increased the levels of AST/ALT and the inflammatory factors IL-6, IL-1β and TNF-a. Omics data suggested intravenous administration of MSNs perturbed the following metabolites: succinate, hypoxanthine, GSSG, NADP+, NADPH and 6-phosphogluconic acid. In addition, increases in GPX, SOD3, G6PD, HK, and PFK at proteomic and transcriptomic levels suggested elevation of glycolysis and pentose phosphate pathway, synthesis of glutathione and nucleotides, and antioxidative pathway activity, whereas oxidative phosphorylation, TCA and mitochondrial energy metabolism were reduced. On the other hand, oral administration of MSNs disturbed inflammatory factors and metabolites of ribose-5-phosphate, 6-phosphogluconate, GSSG, and NADP+ associated with the pentose phosphate pathway, glutathione synthesis and oxidative stress albeit to a lesser extent than intravenous injection despite the administration of a ten-fold greater dose. Overall, systematic biological data suggested that intravenous injection of nanoparticles of pharmaceutical excipients substantially affected hepatic metabolism function and induced oxidative stress and inflammation, whereas oral administration exhibited milder effects compared with intravenous injection.

Effect of formononetin from Trifolium pratense L. on oxidative stress, energy metabolism and inflammatory response after cerebral ischemia-reperfusion injury in mice

Cerebral ischemia-reperfusion injury (CIRI) is one of the main diseases leading to death and disability. Studying the role and mechanism of drugs in mitigating CIRI is of great significance. In the present study, the effect of formononetin from Trifolium pratense L. on oxidative stress, energy metabolism impairment and inflammatory response after cerebral ischemia-reperfusion injury (CIRI) in mice were investigated. Formononetin was extracted from Trifolium pratense L. and was purified. The mice were treated with formononetin for six days. Then, the CIRI model was established. After 24 h of reperfusion, compared with model group, in formononetin group, the neurological deficit score, cerebral water content and cerebral infarction rate were significantly decreased, the brain tissue nitric oxide and malondialdehyde levels were significantly decreased, the brain tissue superoxide dismutase level was significantly increased, the brain tissue Na+-K+-ATPase, Ca2+-Mg2+-ATPase and Ca2+-ATPase activities were significantly increased, and the brain tissue tumor necrosis factor α, interleukin 1β and interleukin 6 levels were significantly decreased. In conclusion, formononetin from Trifolium pratense L. can reduce the oxidative stress, energy metabolism impairment and inflammatory response in brain tissues, thus mitigating the CIRI in mice.

Product inhibition of mammalian thiamine pyrophosphokinase is an important mechanism for maintaining thiamine diphosphate homeostasis

BackgroundThiamine diphosphate (ThDP), an indispensable cofactor for oxidative energy metabolism, is synthesized through the reaction thiamine + ATP ⇆ ThDP + AMP, catalyzed by thiamine pyrophosphokinase 1 (TPK1), a cytosolic dimeric enzyme. It was claimed that the equilibrium of the reaction is in favor of the formation of thiamine and ATP, at odds with thermodynamic calculations. Here we show that this discrepancy is due to feedback inhibition by the product ThDP. MethodsWe used a purified recombinant mouse TPK1 to study reaction kinetics in the forward (physiological) and for the first time also in the reverse direction. ResultsKeq values reported previously are strongly underestimated, due to the fact the reaction in the forward direction rapidly slows down and reaches a pseudo-equilibrium as ThDP accumulates. We found that ThDP is a potent non-competitive inhibitor (Ki ≈ 0.4 μM) of the forward reaction. In the reverse direction, a true equilibrium is reached with a Keq of about 2 × 10−5, strongly in favor of ThDP formation. In the reverse direction, we found a very low Km for ThDP (0.05 μM), in agreement with a tight binding of ThDP to the enzyme. General significanceInhibition of TPK1 by ThDP explains why intracellular ThDP levels remain low after administration of even very high doses of thiamine. Understanding the consequences of this feedback inhibition is essential for developing reliable methods for measuring TPK activity in tissue extracts and for optimizing the therapeutic use of thiamine and its prodrugs with higher bioavailability under pathological conditions.

AMPK-PINK1/Parkin Mediated Mitophagy Is Necessary for Alleviating Oxidative Stress-Induced Intestinal Epithelial Barrier Damage and Mitochondrial Energy Metabolism Dysfunction in IPEC-J2.

The imbalance of redox biology and oxidative stress leads to intestinal barrier injury and mitophagy. However, much uncertainty still exists about the role of mitophagy in oxidative stress and intestinal function. Here, we showed the effects of hydrogen peroxide (H2O2)-induced oxidative stress on intestinal epithelial cell oxidation balance, intestinal barrier function and mitochondrial energy metabolism and its underlying mechanism. In this study, we found that H2O2-induced oxidative stress activated adenosine monophosphate-activated protein kinase (AMPK) and enhanced mitophagy in intestinal porcine epithelial cells (IPEC-J2). While compound C (AMPK inhibitor) and mdivi-1 (mitophagy inhibitor) significantly reduced the activity of superoxide dismutase (SOD) and increased mitochondrial reactive oxygen species (ROS) levels in H2O2 treated cells. Moreover, compound C and mdivi-1 significantly reduced the trans-epithelium electrical resistant (TER) and increased the fluorescein isothiocyanate-dextran (FD4) flux in H2O2 treated IPEC-J2. Furthermore, compound C and mdivi-1 significantly reduced the activity of mitochondrial complex II. Seahorse XF96 data showed that compound C + mdivi-1+ H2O2 treatment significantly reduced maximum respiratory oxygen consumption and spare respiratory capacity. Additionally, compound C or mdivi-1 treatment reduced the formation of mitochondrial autophagosomes. These results unveiled that AMPK and PINK1/Parkin mediated mitophagy is necessary for alleviating oxidative stress induced intestinal epithelial barrier damage and mitochondrial energy metabolism dysfunction in IPEC-J2.

The study of sirtuins in Alzheimer's disease.

Previous studies have shown sirtuins 3 has neuroprotective effects in regulating oxidative stress and energy metabolism in Alzheimer's disease. However, it is unclear whether other sirtuins are associated with cognitive performance and pathological changes in AD. We used postmortem brains of AD (n= 16), mild cognitive impairment (n= 11) and age- and education-matched cognitively normal (CN, n= 11) subjects from the Banner Sun Health Research Institute Brain Bank. We measured the protein levels of Sirt1-7, synaptic proteins, nucleus signal molecules, AD pathology and cognitive performance. Besides Sirt3 as we previously reported, only Sirt6 level was reduced in the middle temporal gyrus of AD subjects compared to that of CN. This reduction was associated with the severity of tau pathology and poorer cognitive performance, which was consistent with impaired synaptic integrity. This study has shown that Sirt6 is downregulated in AD and is related to synaptic loss. Sirt6 may play a critical role in pathogenesis of AD.

CSF protein panels reflecting multiple pathophysiological mechanisms for early and specific diagnosis of Alzheimer’s disease

AbstractBackgroundThe development of disease‐modifying therapies against Alzheimer’s disease (AD) requires biomarker panels that reflect the diverse pathological pathways specifically involved in AD. Here we aimed to identify and validate panels of cerebrospinal fluid (CSF) proteins covering different molecular pathways for early and specific diagnosis of AD.MethodWe measured 665 proteins in 797 CSF samples from patients with mild cognitive impairment with abnormal amyloid (MCI(Aβ+): n=50), AD‐dementia (n=230), non‐AD dementias (n=322; 123 DLB and 199 FTD) and cognitively‐unimpaired controls (n=195; classical AD CSF biomarkers negative) using proximity ligation‐based multiplex immunoassays. Nested and penalized linear modeling were used to identify protein differences (q<0,05) and translatable classification signatures.ResultWe detected highly dysregulated CSF proteins in MCI(Aβ+) or AD compared to controls (112 and 288 proteins respectively, lowest q:1‐15 and 1‐23), as well as between AD and non‐AD dementias (469 proteins; lowest q:1‐29). We confirmed previous findings (e.g., DDAH1, ENO2, PARK7), but we also identified novel proteins especially associated to the prodromal and/or dementia AD stages (e.g., ABL1, SCD4, ENTPD5). Proteins dysregulated in MCI(Aβ+) were primarily related to oxidative stress and energy metabolism, while those specifically dysregulated in later stages of AD dementia were related to cell remodeling, vascular function and immune system. Using penalised generalised linear modeling we identified the minimal number of markers with maximal power to discriminate clinical groups: for MCI(Aβ+) vs. controls: 10‐CSF proteins, AUC:0.99 (95%CI:0.97‐1); for AD vs. controls: 8‐CSF proteins, AUC:0.95 (95%CI:0.92‐0.99) and for AD vs. non‐AD dementias: 9‐CSF proteins, AUC:0.87 (95%CI:0.81‐0.93). The CSF panel discriminating AD from cognitively unimpaired controls was validated in an independent external cohort (n=62, AUC:0.94). Only 3 proteins overlapped across panels, suggesting that the panels with the strongest discriminative power are specific for disease stage and clinical group.ConclusionThis unprecedented large and protein‐rich CSF study indicates that CSF proteome follows a highly dynamic trajectory with distinct CSF profiles associated to different biological processes along the AD continuum. We unveil optimal CSF biomarker panels reflecting the specific multifactorial nature of AD, which can be now translated into customised assays for widespread validation and potential use in heterogeneous diagnostic settings or clinical trials.

Abstract 12247: Mitochondrial Metabolic Transcriptome Profiles During Cardiomyocyte Differentiation From Mouse and Human Pluripotent Stem Cells

Introduction: Simultaneous increase of myofibrils and mitochondria is a key process of cardiomyocyte differentiation from pluripotent stem cells (PSCs). Specifically, development of mitochondrial oxidative energy metabolism in cardiomyocytes is essential to providing the beating function. Although previous studies reported that mitochondrial oxidative metabolism have some correlation with the differentiation of cardiomyocytes, the mechanism by which mitochondrial oxidative metabolism is regulated and the link between cardiomyogenesis and mitochondrial function are still poorly understood. Methods: We performed transcriptome analysis on cells at specific stages of cardiomyocyte differentiation from mouse embryonic stem cells (mESCs) and human induced PSCs (hiPSCs). We selected highly upregulated mitochondrial metabolic genes at cardiac lineage commitment and time-dependent manner during cardiomyocyte differentiation and identified the protein-protein interaction network connecting between mitochondrial metabolic and cardiac developmental genes. Results: We found several mitochondrial metabolic regulatory genes at cardiac lineage commitment (Cck, Bdnf, Fabp4, Cebpa, Cdkn2a in mESC-derived cells and CCK, NOS3 in hiPSC-derived cells) and time-dependent manner during cardiomyocyte differentiation (Eno3, Pgam2, Cox6a2, Fabp3 in mESC-derived cells and PGAM2, SLC25A4 in hiPSC-derived cells). Notably, mitochondrial metabolic proteins are highly interacted with cardiac developmental proteins time-dependent manner during cardiomyocyte differentiation rather than cardiac lineage commitment. Furthermore, mitochondrial metabolic proteins are mainly interacted with cardiac muscle contractile proteins rather than cardiac transcription factors in cardiomyocyte. Conclusions: Mitochondrial metabolism is critical at cardiac maturation rather than cardiac lineage commitment.

Metal stresses modify soluble proteomes and toxin profiles in two Mediterranean strains of the distributed dinoflagellate Alexandrium pacificum

HABs involving Alexandrium pacificum have been reported in metal-contaminated ecosystems, suggesting that this distributed species adapts to and/or can tolerate the effects of metals. Modifications in soluble proteomes and PST contents were characterized in two Mediterranean A. pacificum strains exposed to mono- or polymetallic stresses (zinc, lead, copper, cadmium). These strains were isolated from two anthropized locations: Santa Giusta Lagoon (Italy, SG C10-3) and the Tarragona seaport (Spain, TAR C5-4F). In both strains, metals primarily downregulated key photosynthesis proteins. Metals also upregulated other proteins involved in photosynthesis (PCP in both strains), the oxidative stress response (HSP 60, proteasome and SOD in SG C10-3; HSP 70 in TAR C5-4F), energy metabolism (AdK in TAR C5-4F), neoglucogenesis/glycolysis (GAPDH and PEP synthase in SG C10-3) and protein modification (PP in TAR C5-4F). These proteins, possibly involved in adaptive proteomic responses, may explain the development of these A. pacificum strains in metal-contaminated ecosystems. The two strains showed different proteomic responses to metals, with SG C10-3 upregulating more proteins, particularly PCP. Among the PSTs, regardless of the metal and the strain studied, C2 and GTX4 predominated, followed by GTX5. Under the polymetallic cocktail, (i) total PSTs, C2 and GTX4 reached the highest levels in SG C10-3 only, and (ii) total PSTs, C2, GTX5 and neoSTX were higher in SG C10-3 than in TAR C5-4F, whereas in SG C10-3 under copper stress, total PSTs, GTX5, GTX1 and C1 were higher than in the controls, revealing variability in PST biosynthesis between the two strains. Total PSTs, C2, GTX4 and GTX1 showed significant positive correlations with PCP, indicating that PST production may be positively related to photosynthesis. Our results showed that the A. pacificum strains adapt their proteomic and physiological responses to metals, which may contribute to their ecological success in highly anthropized areas.

TAMI-17. INDUCTION OF SYNTHETIC LETHALITY BY ACTIVATION OF MITOCHONDRIAL CLPP AND INHIBITION OF HDAC1/2 IN GLIOBLASTOMA

Abstract Activation of the mitochondrial ClpP protease is an innovative therapeutic concept and the identification of synthetic lethal interactions may foster the development of novel therapies for glioblastoma (GBM). By integration of a transcriptome, metabolite and U-13C-glucose tracing analyses, we showed that activation of the mitochondrial ClpP protease through constitutively active ClpP (Y118A) or utilization of second-generation imipridone compounds (ONC206 and ONC212) in combination with genetic interference of HDAC1 and HDAC2 as well as with global (Panobinostat) and selective (Romidepsin) HDAC inhibitors caused synergistic reduction of viability in established, neuro-sphere and patient-derived xenograft (PDX) cultures of human GBM, which was mediated by interference with tricarboxylic acid cycle activity and GBM cell respiration. Notably, human astrocytes were significantly less susceptible to the combination treatment of HDAC-inhibitors and ClpP activators. The reduction of GBM viability occurred independent of TP53 status and was accompanied by activation of cell death with apoptotic features along with cleavage of caspases regulated chiefly by Bcl-xL and Mcl-1. Importantly, knockdown of the ClpP protease or ectopic expression of a ClpP D190A mutant almost completely rescued from the inhibition of oxidative energy metabolism as well as from the reduction of cellular viability by ClpP activators and the combination treatment, suggesting critical involvement of this protein. Finally, utilizing GBM PDX models, we demonstrated that the combination treatment of HDAC-inhibitors and imipridones reduced tumor growth and prolonged host survival more potently than single treatments or vehicle in vivo. Collectively, these observations suggest that the efficacy of HDAC inhibitors might be significantly enhanced through ClpP activators in model systems of human GBM.

Oxidative Stress and Energy Metabolism in the Brain: Midlife as a Turning Point.

Neural tissue is one of the main oxygen consumers in the mammalian body, and a plentitude of metabolic as well as signaling processes within the brain is accompanied by the generation of reactive oxygen (ROS) and nitrogen (RNS) species. Besides the important signaling roles, both ROS and RNS can damage/modify the self-derived cellular components thus promoting neuroinflammation and oxidative stress. While previously, the latter processes were thought to progress linearly with age, newer data point to midlife as a critical turning point. Here, we describe (i) the main pathways leading to ROS/RNS generation within the brain, (ii) the main defense systems for their neutralization and (iii) summarize the recent literature about considerable changes in the energy/ROS homeostasis as well as activation state of the brain’s immune system at midlife. Finally, we discuss the role of calorie restriction as a readily available and cost-efficient antiaging and antioxidant lifestyle intervention.

18β‐glycyrrhetinic acid improves high‐intensity exercise performance by promoting glucose‐dependent energy production and inhibiting oxidative stress in mice

It has been shown that 18β-glycyrrhetinic acid (18β-GA), the main bioactive compound of licorice, can modulate oxidative stress and metabolic processes in liver and skin. Given the critical role of oxidative stress and energy metabolism in exercise-induced fatigue, we hypothesized that 18β-GA could exert an ergogenic action by inhibiting excess reactive oxygen species (ROS) induction and promoting energy production in muscles. Mice were gavage-fed with 18β-GA for four consecutive days. Running ability was assessed based on the exhaustive treadmill test with high- and moderate-intensity. Western blot analysis, enzyme-linked immunosorbent assay, and immunofluorescence staining were used to measure the changes of muscle fatigue-related markers, oxidative stress status, and energy metabolism in response to 18β-GA exposure. Treatment with 18β-GA significantly increased the exhaustive running distance (~37%) in the high-intensity exercise, but not in the moderate-intensity exercise. Mechanistically, reduction of oxidative stress and induction of antioxidants (SOD, CAT, and GSH) by 18β-GA were observed. Moreover, 18β-GA treatment caused an improved preservation of muscle glycogen (12%), which was associated with upregulation of glucose transporter 4 (GLUT4) (91%) and increased insulin level (17%). The findings of the present study clearly suggest that 18β-GA holds excellent potential as a novel bioactive agent against high-intensity exercise-induced fatigue.

Proteome Analysis of Whole-Body Responses in Medaka Experimentally Exposed to Fish-Killing Dinoflagellate Karenia mikimotoi.

Karenia mikimotoi is a well-known harmful algal bloom species. Blooms of this dinoflagellate have become a serious threat to marine life, including fish, shellfish, and zooplanktons and are usually associated with massive fish death. Despite the discovery of several toxins such as gymnocins and gymnodimines in K. mikimotoi, the mechanisms underlying the ichthyotoxicity of this species remain unclear, and molecular studies on this topic have never been reported. The present study investigates the fish-killing mechanisms of K. mikimotoi through comparative proteomic analysis. Marine medaka, a model fish organism, was exposed to K. mikimotoi for a three-part time period (LT25, LT50 and LT90). Proteins extracted from the whole fish were separated by using two-dimensional gel electrophoresis, and differentially expressed proteins were identified with reference to an untreated control. The change in fish proteomes over the time-course of exposure were analyzed. A total of 35 differential protein spots covering 19 different proteins were identified, of which most began to show significant change in expression levels at the earliest stage of intoxication. Among the 19 identified proteins, some are closely related to the oxidative stress responses, energy metabolism, and muscle contraction. We propose that oxidative stress-mediated muscle damage might explain the symptoms developed during the ichthyotoxicity test, such as gasping for breath, loss of balance, and body twitching. Our findings lay the foundations for more in-depth studies of the mechanisms of K. mikimotoi’s ichthyotoxicity.

A Quantitative Proteomics Approach to Gain Insight into NRF2-KEAP1 Skeletal Muscle System and Its Cysteine Redox Regulation.

Mammalian skeletal muscle (SkM) tissue engages the Nrf2-Keap1-dependent antioxidant defense mechanism to respond adaptively to stress. Redox homeostasis mediated by the reversible modification of selective cysteines is the prevalent mode of regulation. The protein targets of SkM redox regulation are largely unknown. We previously reported the proteomic profiles of soleus (Sol) and extensor digitorum longus (EDL) with Nrf2 or Keap1 gene deletion, using SkM-specific Nrf2 or Keap1 knockout models; iMS-Nrf2flox/flox; and iMS-Keap1flox/flox. Here, we employed these two animal models to understand the global expression profile of red tibialis anterior (RTA) using a label free approach and its redox proteomics using iodoacetyl tandem mass tag (iodoTMTTM)-labeled cysteine quantitation. We quantified 298 proteins that were significantly altered globally in the RTA with Nrf2 deficiency but only 21 proteins in the Keap1 KO samples. These proteins are involved in four intracellular signaling pathways: sirtuin signaling, Nrf2 mediated oxidative stress response, oxidative phosphorylation, and mitochondrion dysfunction. Moreover, we identified and quantified the cysteine redox peptides of 34 proteins, which are associated with mitochondrial oxidative phosphorylation, energy metabolism, and extracellular matrix. Our findings suggest that Nrf2-deficient RTA is implicated in metabolic myopathy, mitochondrial disorders, and motor dysfunction, possibly due to an enhanced oxidative modification of the structure and functional proteins in skeletal myocytes.

Graphene-triphenyl phosphate (TPP) co-exposure in the marine environment: Interference with metabolism and immune regulation in mussel Mytilus galloprovincialis

Both immune regulation and endocrine systems are great challenges to marine organisms, and effective protocols for determining these adverse outcome pathways are limited, especially in vivo. The increasing usage of graphene nanomaterials can lead to the frequent exposure to marine organisms. Triphenyl phosphate (TPP), an organophosphate flame retardant, is frequently detected in natural environments. In this study, the combined toxic effects of co-exposure to graphene and TPP was investigated in Mytilus galloprovincialis using computational toxicology and multi-omics technology. Noticeably, graphene could disturb the membrane stability and increase the tissue accumulation of TPP. The adsorption behavior of TPP on graphene could inhibit the surface activity of graphene. In the digestive gland, transcriptomics analysis revealed the down-regulated genes in graphene + TPP treatment, including glyceraldehyde-3-phosphate dehydrogenase (GAPDH), sorbitol dehydrogenase (SORD), glutathione s-transferase mu 3 (GSTM3) and 4-aminobutyrate aminotransferase (ABAT), were mainly associated with oxidative stress and energy metabolism. Moreover, metabolic responses indicated that graphene + TPP could cause disturbances in energy metabolism and osmotic regulation marked by differentially altered ATP, glucose and taurine in mussels. These data underline the need for further knowledge on the potential interactions of nanomaterials with existing contaminants in marine organisms.

Hepatotoxicity or hepatoprotection of emodin? Two sides of the same coin by 1H-NMR metabolomics profiling

Emodin is the major anthraquinone component of many important traditional Chinese herbs, such as Rheum palmatum L. and Polygonum multiflorum Thunb. They have been popular health products but recently aroused concerns about their hepatotoxicity, which are believed to be arising from the contained anthraquinones, such as emodin. However, emodin exerts potent hepatoprotective ability, such as anti-fibrotic, anti-oxidative, and anti-inflammatory effects. In this study, 1H NMR based metabolomics approach, complemented with histopathological observation, biochemical measurements, western blotting analysis and real-time quantitative PCR (RT-qPCR), was applied to interpret the paradox of emodin (30 mg/kg, 10 mg/kg BW) using both healthy mice (male, ICR) and chronic CCl4-injured mice (0.1 mL/kg, 0.35% CCl4, 3 times a week for a month). Emodin exerted a weight loss property associated with its lipid-lowing effects, which helped alleviate CCl4-induced steatosis. Emodin effectively ameliorated CCl4-induced oxidative stress and energy metabolism dysfunction in mice liver via regulating glucose, lipid and amino acid metabolism, and inhibited excessive inflammatory response. In healthy mice, emodin only exhibited hepatoxicity on high-dosage by disturbing hepatic anti-oxidant homeostasis, especially GSH and xanthine metabolism. This integrated metabolomics approach identified the bidirectional potential of emodin, which are important for its rational use.

ITRAQ-based proteomic analysis provides insights into the molecular mechanisms of rice formyl tetrahydrofolate deformylase in salt response.

A new molecular mechanism of tetrahydrofolate deformylase involved in the salt response presumably affects mitochondrial and chloroplast function by regulating energy metabolism and accumulation of reactive oxygen species. High salinity severely restrains plant growth and development, consequently leading to a reduction in grain yield. It is therefore critical to identify the components involved in plant salt resistance. In our previous study, we identified a rice leaf early-senescence mutant hpa1, which encodes a formyl tetrahydrofolate deformylase (Xiong et al. in Sci China Life Sci 64(5):720-738, 2021). Here, we report that HPA1 also plays a role in the salt response. To explore the molecular mechanism of HPA1 in salt resistance, we attempted to identify the differentially expressed proteins between wild type and hpa1 mutant for salinity treatment using an iTRAQ-based comparative protein quantification approach. A total of 4598 proteins were identified, of which 279 were significantly altered, including 177 up- and 102 down-regulated proteins. A functional analysis suggested that the 279 differentially expressed proteins are involved mainly in the regulation of oxidative phosphorylation, phenylpropanoid biosynthesis, photosynthesis, posttranslational modifications, protein turnover and energy metabolism. Moreover, a deficiency in HPA1 impaired chlorophyll metabolism and photosynthesis in chloroplasts and affected the electron flow of the electron transport chain in mitochondria. These changes led to abnormal energy metabolism and accumulation of reactive oxygen species, which may affect the permeability and integrity of cell membranes, leading to cell death. In addition, the results were verified by transcriptional or physiological experiments. Our results provide an insight into a new molecular mechanism of the tetrahydrofolate cycle protein formyl tetrahydrofolate deformylase, which is involved in the salt response, presumably by affecting mitochondrial and chloroplast function regulating energy metabolism and accumulation of reactive oxygen species under salt stress.