ATP Synthase: Structure, Function and Inhibition

Photo-activation of mitochondrial ATP synthesis

ATP production by mitochondria isolated from Saccharomyces cerevisiae cells was accelerated upon both direct and indirect mitochondrial photo-activation (MPA). The extent of direct MPA was dependent on the wavelength of excitation light. Direct MPA was created by light in cytochrome c spectral absorption bands (440, 520 and 550 nm), this light was absorbed producing electronically excited cytochrome c, and the excitation energy of the latter was used in the ATP production chain. The activity of cytochrome c was tested with 600 nm light, where cytochrome c does not absorb, and thus ATP production rate remained the same as in darkness. Note that ATP production rates were significantly larger under light at 550, 520 and 440 nm. Therefore, photo-activation of cytochrome c was the first step of MPA synthesis of ATP. Indirect MPA of ATP production also proceeded via electronically excited cytochrome c, by energy transfer from electronically excited Co/BN film to cytochrome c located in the inner mitochondrial membrane (IMM). Co/BN excitons were generated by photons absorbed by the Co/BN film, which was not in contact with the mitochondrial sample. Next, these excitons propagated along the Co/BN film to the part of the film that was in contact with the mitochondrial sample. There the exciton energy was transferred to cytochrome c located in the IMM, producing electronically excited cytochrome c. Thus, excited cytochrome c was generated in a way different from that of direct MPA. Next, the energy of excited cytochrome c was used in activated ATP synthesis, with virtually the same effect for 519 and 427 nm excitation. Thus, the first step of ATP synthesis in indirect MPA was the exciton energy transfer from Co/BN film to cytochrome c located in the IMM, producing an electronically excited cytochrome c molecule. A phenomenological mechanism of direct and indirect MPA was proposed, and the model parameters were obtained by fitting the model to the experimental data. However, more information is needed before the detailed mechanism of ATP synthesis activation by electronically excited cytochrome c could be understood. The present results support the earlier proposed hypothesis of indirect MPA of ATP production in vertebrate retina in daylight.

Network Analysis Reveals Different Cellulose Degradation Strategies Across Trichoderma harzianum Strains Associated With XYR1 and CRE1

Trichoderma harzianum, whose gene expression is tightly controlled by the transcription factors (TFs) XYR1 and CRE1, is a potential candidate for hydrolytic enzyme production. Here, we performed a network analysis of T. harzianum IOC-3844 and T. harzianum CBMAI-0179 to explore how the regulation of these TFs varies between these strains. In addition, we explored the evolutionary relationships of XYR1 and CRE1 protein sequences among Trichoderma spp. The results of the T. harzianum strains were compared with those of Trichoderma atroviride CBMAI-0020, a mycoparasitic species. Although transcripts encoding carbohydrate-active enzymes (CAZymes), TFs, transporters, and proteins with unknown functions were coexpressed with cre1 or xyr1, other proteins indirectly related to cellulose degradation were identified. The enriched GO terms describing the transcripts of these groups differed across all strains, and several metabolic pathways with high similarity between both regulators but strain-specific differences were identified. In addition, the CRE1 and XYR1 subnetworks presented different topology profiles in each strain, likely indicating differences in the influences of these regulators according to the fungi. The hubs of the cre1 and xyr1 groups included transcripts not yet characterized or described as being related to cellulose degradation. The first-neighbor analyses confirmed the results of the profile of the coexpressed transcripts in cre1 and xyr1. The analyses of the shortest paths revealed that CAZymes upregulated under cellulose degradation conditions are most closely related to both regulators, and new targets between such signaling pathways were discovered. Although the evaluated T. harzianum strains are phylogenetically close and their amino acid sequences related to XYR1 and CRE1 are very similar, the set of transcripts related to xyr1 and cre1 differed, suggesting that each T. harzianum strain used a specific regulation strategy for cellulose degradation. More interestingly, our findings may suggest that XYR1 and CRE1 indirectly regulate genes encoding proteins related to cellulose degradation in the evaluated T. harzianum strains. An improved understanding of the basic biology of fungi during the cellulose degradation process can contribute to the use of their enzymes in several biotechnological applications and pave the way for further studies on the differences across strains of the same species.

Recent Advances in Modeling Mitochondrial Cardiomyopathy Using Human Induced Pluripotent Stem Cells

Around one third of patients with mitochondrial disorders develop a kind of cardiomyopathy. In these cases, severity is quite variable ranging from asymptomatic status to severe manifestations including heart failure, arrhythmias, and sudden cardiac death. ATP is primarily generated in the mitochondrial respiratory chain via oxidative phosphorylation by utilizing fatty acids and carbohydrates. Genes in both the nuclear and the mitochondrial DNA encode components of this metabolic route and, although mutations in these genes are extremely rare, the risk to develop cardiac symptoms is significantly higher in this patient cohort. Additionally, infants with cardiovascular compromise in mitochondrial deficiency display a worse late survival compared to patients without cardiac symptoms. At this point, the mechanisms behind cardiac disease progression related to mitochondrial gene mutations are poorly understood and current therapies are unable to substantially restore the cardiac performance and to reduce the disease burden. Therefore, new strategies are needed to uncover the pathophysiological mechanisms and to identify new therapeutic options for mitochondrial cardiomyopathies. Here, human induced pluripotent stem cell (iPSC) technology has emerged to provide a suitable patient-specific model system by recapitulating major characteristics of the disease in vitro, as well as to offer a powerful platform for pre-clinical drug development and for the testing of novel therapeutic options. In the present review, we summarize recent advances in iPSC-based disease modeling of mitochondrial cardiomyopathies and explore the patho-mechanistic insights as well as new therapeutic approaches that were uncovered with this experimental platform. Further, we discuss the challenges and limitations of this technology and provide an overview of the latest techniques to promote metabolic and functional maturation of iPSC-derived cardiomyocytes that might be necessary for modeling of mitochondrial disorders.

Simultaneous preconcentration and fluorescence detection of ATP by a hybrid nanocomposite of magnetic nanoparticles incorporated in mixed metal hydroxide

A new approach for increasing the sensitivity of adenosine triphosphate (ATP) detection was demonstrated. The assay was based on the synergetic function of a hybrid nanocomposite (MNPs@MMH) composed of magnetic nanoparticles (MNPs) incorporated in a mixed metal hydroxide (MMH). MNPs@MMH can be utilized as an efficient green extractant and peroxidase catalyst. The trace level of ATP in the sample solution was first extracted by the MNPs@MMH hybrid nanocomposite through the ion exchange properties of MMH and adsorbed on the surface of the MNPs@MMH. The concentration of ATP was related to the fluorescence intensity of 2,3-diaminophenazine (DAP) generated from peroxidase-like activity of the MNPs in the presence of H₂O₂ and o-phenylenediamine (OPD). In the presence of ATP, the active surface of the MNPs was diminished, and the amount of DAP generated was reduced. Thus, the concentration of ATP was related to the degree of fluorescence decrease compared to the fluorescence intensity of the system without ATP. Based on the proposed strategy, a highly sensitive assay for ATP was achieved. This assay exhibited good selectivity for detection of ATP over derivatives and other common anions. The proposed assay allowed the detection of ATP in a concentration range of 2.5-20 μM with a detection limit of 0.41 μM.

Mitochondria as a target and central hub of energy division during cold stress in insects

Temperature stress is one of the crucial factors determining geographical distribution of insect species. Most of them are active in moderate temperatures, however some are capable of surviving in extremely high as well as low temperatures, including freezing. The tolerance of cold stress is a result of various adaptation strategies, among others the mitochondria are an important player. They supply cells with the most prominent energy carrier—ATP, needed for their life processes, but also take part in many other processes like growth, aging, protection against stress injuries or cell death. Under cold stress, the mitochondria activity changes in various manner, partially to minimize the damages caused by the cold stress, partially because of the decline in mitochondrial homeostasis by chill injuries. In the response to low temperature, modifications in mitochondrial gene expression, mtDNA amount or phosphorylation efficiency can be observed. So far study also showed an increase or decrease in mitochondria number, their shape and mitochondrial membrane permeability. Some of the changes are a trigger for apoptosis induced via mitochondrial pathway, that protects the whole organism against chill injuries occurring on the cellular level. In many cases, the observed modifications are not unequivocal and depend strongly on many factors including cold acclimation, duration and severity of cold stress or environmental conditions. In the presented article, we summarize the current knowledge about insect response to cold stress focusing on the role of mitochondria in that process considering differences in results obtained in different experimental conditions, as well as depending on insect species. These differentiated observations clearly indicate that it is still much to explore.

Effect of surfactants on the production of polysaccharides from Schizophyllum commune through submerged fermentation

Schizophyllum commune (S. commune) polysaccharides are biomacromolecules with multiple biological activities and wide applications. In this study, polysaccharide production through submerged fermentation of S. commune using different surfactants was investigated. The addition of 1 g/L of polyoxyethylene sorbitan monooleate (Tween 80) at the beginning of the fermentation showed the best promotional effects on collective exopolysaccharide (EPS) production (which increased by 37.17%) while shortening the production cycle by 2 days. The monosaccharide composition of the EPS produced when the added Tween 80 was similar to that of the control; however, the molecular weight (Mw) was lower. Notably, the addition of Tween 80 significantly increased the ATP levels and the transcription levels of phosphoglucomutase and β-glucan synthase genes in the polysaccharide synthesis pathway. The addition of Tween 80 reduced the pellet size of the mycelium compared to that of the control, but did not significantly change the microstructure of the mycelial cells. This study proposes an efficient strategy for the production of polysaccharides through submerged fermentation of S. commune, and elucidates the detailed mechanism of using Tween 80 as a fermentation stimulatory reagent.

Mechanobiology of muscle and myofibril morphogenesis

Muscles generate forces for animal locomotion. The contractile apparatus of muscles is the sarcomere, a highly regular array of large actin and myosin filaments linked by gigantic titin springs. During muscle development many sarcomeres assemble in series into long periodic myofibrils that mechanically connect the attached skeleton elements. Thus, ATP-driven myosin forces can power movement of the skeleton. Here we review muscle and myofibril morphogenesis, with a particular focus on their mechanobiology. We describe recent progress on the molecular structure of sarcomeres and their mechanical connections to the skeleton. We discuss current models predicting how tension coordinates the assembly of key sarcomeric components to periodic myofibrils that then further mature during development. This requires transcriptional feedback mechanisms that may help to coordinate myofibril assembly and maturation states with the transcriptional program. To fuel the varying energy demands of muscles we also discuss the close mechanical interactions of myofibrils with mitochondria and nuclei to optimally support powerful or enduring muscle fibers.

Proteomic Analysis Identifies NDUFS1 and ATP5O as Novel Markers for Survival Outcome in Prostate Cancer

We aimed to identify novel markers for aggressive prostate cancer in a STAT3-low proteomics-derived dataset of mitochondrial proteins by immunohistochemical analysis and correlation with transcriptomic data and biochemical recurrence in a STAT3 independent PCa cohort. Formalin-fixed paraffin-embedded tissue (FFPE) sample selection for proteomic analysis and tissue-microarray (TMA) generation was conducted from a cohort of PCa patients. Retrospective data analysis was performed with the same cohort. 153 proteins differentially expressed between STAT3-low and STAT3-high samples were identified. Out of these, 46 proteins were associated with mitochondrial processes including oxidative phosphorylation (OXPHOS), and 45 proteins were upregulated, including NDUFS1/ATP5O. In a STAT3 independent PCa cohort, high expression of NDUFS1/ATP5O was confirmed by immunocytochemistry (IHC) and was significantly associated with earlier biochemical recurrence (BCR). mRNA expression levels for these two genes were significantly higher in intra-epithelial neoplasia and in PCa compared to benign prostate glands. NDUFS1/ATP5O levels are increased both at the mRNA and protein level in aggressive PCa. Our results provide evidence that NDUFS1/ATP5O could be used to identify high-risk PCa patients.

Mitochondria as a Cellular Hub in Infection and Inflammation

Mitochondria are the energy center of the cell. They are found in the cell cytoplasm as dynamic networks where they adapt energy production based on the cell’s needs. They are also at the center of the proinflammatory response and have essential roles in the response against pathogenic infections. Mitochondria are a major site for production of Reactive Oxygen Species (ROS; or free radicals), which are essential to fight infection. However, excessive and uncontrolled production can become deleterious to the cell, leading to mitochondrial and tissue damage. Pathogens exploit the role of mitochondria during infection by affecting the oxidative phosphorylation mechanism (OXPHOS), mitochondrial network and disrupting the communication between the nucleus and the mitochondria. The role of mitochondria in these biological processes makes these organelle good targets for the development of therapeutic strategies. In this review, we presented a summary of the endosymbiotic origin of mitochondria and their involvement in the pathogen response, as well as the potential promising mitochondrial targets for the fight against infectious diseases and chronic inflammatory diseases.

Rapid and delayed effects of single-walled carbon nanotubes in glioma cells

Single-walled carbon nanotubes (SWCNTs) demonstrate a strong potential as an optically activated theranostic nano-agent. However, using SWCNTs in theranostics still requires revealing mechanisms of the SWCNT-mediated effects on cellular functions. Even though rapid and delayed cellular responses can differ significantly and may lead to undesirable consequences, understanding of these mechanisms is still incomplete. We demonstrate that introducing short (150-250 nm) SWCNTs into C6 rat glioma cells leads to SWCNT-driven effects that show pronounced time dependence. Accumulation of SWCNTs is carried out due to endocytosis with modification of the actin cytoskeleton but not accompanied with autophagy. Its initial stage launches a rapid cellular response via significantly heightened mitochondrial membrane potential and superoxide anion radical production, satisfying the cell demand of energy for SWCNT transfer inside the cytoplasm. In the long term, SWCNTs agglomerate to micron-sized structures surrounded by highly active mitochondria having parameters return to control values. SWCNTs postponed effects are also manifested themselves in the suppression of the cell proliferative activity with further restoration after five passages. These results demonstrate relative cellular inertness and safety of SWCNTs eliminating possible side effects caused by optically activated theranostic applications.

Sulfur vacancies affect the environmental fate, corona formation, and microalgae toxicity of molybdenum disulfide nanoflakes

Sulfur vacancy (SV) defects have been engineered in two-dimensional (2D) transition metal dichalcogenides (TMDs) for high performance applications in various fields involving environmental protection. Understanding the influence of SVs on the environmental fate and toxicity of TMDs is critical for evaluating their risk. Our work discovered that SVs (with S/Mo ratios of 1.65 and 1.32) reduced the dispersibility and promoted aggregation of 2H phase molybdenum disulfide (2H-MoS₂, a hot TMD) in aqueous solution. The generation capability of •O₂^- and •OH was increased and the dissolution of 2H-MoS₂ was significantly accelerated after SVs formation. Different with pristine form, S-vacant 2H-MoS₂ preferentially harvested proteins (i.e., forming protein corona) involved in antioxidation, photosynthetic electron transport, and the cytoskeleton structure of microalgae. These proteins contain a higher relative number of thiol groups, which exhibited stronger affinity to S-vacant than pristine 2H-MoS₂, as elucidated by density functional theory calculations. Notably, SVs aggravated algal growth inhibition, oxidative damage, photosynthetic efficiency and cell membrane permeability reduction induced by 2H-MoS₂ due to increased free radical yield and the specific binding of functional proteins. Our findings provide insights into the roles of SVs on the risk of MoS₂ while highlighting the importance of rational design for TMDs application.

Evolutionary rate covariation identifies SLC30A9 (ZnT9) as a mitochondrial zinc transporter

Recent advances in genome sequencing have led to the identification of new ion and metabolite transporters, many of which have not been characterized. Due to the variety of subcellular localizations, cargo and transport mechanisms, such characterization is a daunting task, and predictive approaches focused on the functional context of transporters are very much needed. Here we present a case for identifying a transporter localization using evolutionary rate covariation (ERC), a computational approach based on pairwise correlations of amino acid sequence evolutionary rates across the mammalian phylogeny. As a case study, we find that poorly characterized transporter SLC30A9 (ZnT9) coevolves with several components of the mitochondrial oxidative phosphorylation chain, suggesting mitochondrial localization. We confirmed this computational finding experimentally using recombinant human SLC30A9. SLC30A9 loss caused zinc mishandling in the mitochondria, suggesting that under normal conditions it acts as a zinc exporter. We therefore propose that ERC can be used to predict the functional context of novel transporters and other poorly characterized proteins.

LC-MS/MS Proteomic Study of MCF-7 Cell Treated with Dox and Dox-Loaded Calcium Carbonate Nanoparticles Revealed Changes in Proteins Related to Glycolysis, Actin Signalling, and Energy Metabolism

Simple Summary

This work revealed that DOX-Ar-CC-NPs have the ability to promote cell death in MCF-7 cells, showing high potency in drug delivery. DOX-Ar-CC-NPs prompts cell death of MCF-7 cancer cells in vivo. LC-MS/MS Proteomic experemnt showed alteration on the expression of proteins linked to actine signaling, carbohydrate metabolisim.

Abstract

One of the most prevalent death causes among women worldwide is breast cancer. This study aimed to characterise and differentiate the proteomics profiles of breast cancer cell lines treated with Doxorubicin (DOX) and Doxorubicin-CaCO₃-nanoparticles (DOX-Ar-CC-NPs). This study determines the therapeutic potential of doxorubicin-loaded aragonite CaCO₃ nanoparticles using a Liquid Chromatography/Mass Spectrometry analysis. In total, 334 proteins were expressed in DOX-Ar-CC-NPs treated cells, while DOX treatment expressed only 54 proteins. Out of the 334 proteins expressed in DOX-CC-NPs treated cells, only 36 proteins showed changes in abundance, while in DOX treated cells, only 7 out of 54 proteins were differentially expressed. Most of the 30 identified proteins that are differentially expressed in DOX-CC-NPs treated cells are key enzymes that have an important role in the metabolism of carbohydrates as well as energy, including: pyruvate kinase, ATP synthase, enolase, glyceraldehyde-3-phosphate dehydrogenase, mitochondrial ADP/ATP carrier, and trypsin. Other identified proteins are structural proteins which included; Keratin, α- and β-tubulin, actin, and actinin. Additionally, one of the heat shock proteins was identified, which is Hsp90; other proteins include Annexins and Human epididymis protein 4. While the proteins identified in DOX-treated cells were tubulin alpha-1B chain and a beta chain, actin cytoplasmic 1, annexin A2, IF rod domain-containing protein, and 78 kDa glucose-regulated protein. Bioinformatics analysis revealed the predicted canonical pathways linking the signalling of the actin cytoskeleton, ILK, VEGF, BAG2, integrin and paxillin, as well as glycolysis. This research indicates that proteomic analysis is an effective technique for proteins expression associated with chemotherapy drugs on cancer tumours; this method provides the opportunity to identify treatment targets for MCF-7 cancer cells, and a liquid chromatography-mass spectrometry (LC-MS/MS) system allowed the detection of a larger number of proteins than 2-DE gel analysis, as well as proteins with maximum pIs and high molecular weight.

Targeting Mitochondrial Oxidative Phosphorylation in Glioblastoma Therapy

As a multi-functional cellular organelle, mitochondrial metabolic reprogramming is well recognized as a hallmark of cancer. The center of mitochondrial metabolism is oxidative phosphorylation (OXPHOS), in which cells use enzymes to oxidize nutrients, thereby converting the chemical energy to the biological energy currency ATPs. OXPHOS also creates the mitochondrial membrane potential and serve as the driving force of other mitochondrial metabolic pathways and experiences significant reshape in the different stages of tumor progression. In this minireview, we reviewed the major mitochondrial pathways that are connected to OXPHOS and are affected in cancer cells. In addition, we summarized the function of novel bio-active molecules targeting mitochondrial metabolic processes such as OXPHOS, mitochondrial membrane potential and mitochondrial dynamics. These molecules exhibit intriguing preclinical and clinical results and have been proven to be promising antitumor candidates in recent studies.

Mitochondrial Epigenetics and Environmental Health: Making a Case for Endocrine Disrupting Chemicals

Recent studies implicate mitochondrial dysfunction in the development and progression of numerous chronic diseases, which may be partially due to modifications in mitochondrial DNA (mtDNA). There is also mounting evidence that epigenetic modifications to mtDNA may be an additional layer of regulation that controls mitochondrial biogenesis and function. Several environmental factors (eg, smoking, air pollution) have been associated with altered mtDNA methylation in a handful of mechanistic studies and in observational human studies. However, little is understood about other environmental contaminants that induce mtDNA epigenetic changes. Numerous environmental toxicants are classified as endocrine disrupting chemicals (EDCs). Beyond their actions on hormonal pathways, EDC exposure is associated with elevated oxidative stress, which may occur through or result in mitochondrial dysfunction. Although only a few studies have assessed the impacts of EDCs on mtDNA methylation, the current review provides reasons to consider mtDNA epigenetic disruption as a mechanism of action of EDCs and reviews potential limitations related to currently available evidence. First, there is sufficient evidence that EDCs (including bisphenols and phthalates) directly target mitochondrial function, and more direct evidence is needed to connect this to mtDNA methylation. Second, these and other EDCs are potent modulators of nuclear DNA epigenetics, including DNA methylation and histone modifications. Finally, EDCs have been shown to disrupt several modulators of mtDNA methylation, including DNA methyltransferases and the mitochondrial transcription factor A/nuclear respiratory factor 1 pathway. Taken together, these studies highlight the need for future research evaluating mtDNA epigenetic disruption by EDCs and to detail specific mechanisms responsible for such disruptions.

Effect of Novel Antipsychotics on Energy Metabolism - In Vitro Study in Pig Brain Mitochondria

The identification and quantification of mitochondrial effects of novel antipsychotics (brexpiprazole, cariprazine, loxapine, and lurasidone) were studied in vitro in pig brain mitochondria. Selected parameters of mitochondrial metabolism, electron transport chain (ETC) complexes, citrate synthase (CS), malate dehydrogenase (MDH), monoamine oxidase (MAO), mitochondrial respiration, and total ATP and reactive oxygen species (ROS) production were evaluated and associated with possible adverse effects of drugs. All tested antipsychotics decreased the ETC activities (except for complex IV, which increased in activity after brexpiprazole and loxapine addition). Both complex I- and complex II-linked respiration were dose-dependently inhibited, and significant correlations were found between complex I-linked respiration and both complex I activity (positive correlation) and complex IV activity (negative correlation). All drugs significantly decreased mitochondrial ATP production at higher concentrations. Hydrogen peroxide production was significantly increased at 10 µM brexpiprazole and lurasidone and at 100 µM cariprazine and loxapine. All antipsychotics acted as partial inhibitors of MAO-A, brexpiprazole and loxapine partially inhibited MAO-B. Based on our results, novel antipsychotics probably lacked oxygen uncoupling properties. The mitochondrial effects of novel antipsychotics might contribute on their adverse effects, which are mostly related to decreased ATP production and increased ROS production, while MAO-A inhibition might contribute to their antidepressant effect, and brexpiprazole- and loxapine-induced MAO-B inhibition might likely promote neuroplasticity and neuroprotection. The assessment of drug-induced mitochondrial dysfunctions is important in development of new drugs as well as in the understanding of molecular mechanism of adverse or side drug effects.

TCMIP v2.0 Powers the Identification of Chemical Constituents Available in Xinglou Chengqi Decoction and the Exploration of Pharmacological Mechanisms Acting on Stroke Complicated With Tanre Fushi Syndrome

Xinglou Chengqi (XLCQ) decoction, composed of three botanical drugs and one inorganic drug, is used in clinics during the treatment of acute stroke complicated with Tanre Fushi (TRFS) syndrome in China. However, its active ingredients and the molecular mechanism have not been clarified. So, we aimed to preliminarily characterize its chemical constituents and investigate its pharmacological mechanisms using an integrative pharmacology strategy, including component analysis, network prediction, and experimental verification. We employed UPLC-QTOF-MS/MS to describe the chemical profile of XLCQ, Integrative Pharmacology-based Network Computational Research Platform of Traditional Chinese Medicine (TCMIP v2.0, http://www.tcmip.cn/), to assist in identifying the chemical components and predict the putative molecular mechanism against acute stroke complicated with TRFS, and LPS-stimulated BV-2 cells to verify the anti-neuroinflammatory effects of luteolin, apigenin, and chrysoeriol. Altogether, 197 chemical compounds were identified or tentatively characterized in the water extraction of XLCQ, 22 of them were selected as the key active constituents that may improve the pathological state by regulating 27 corresponding targets that are mainly involved in inflammation/immune-related pathways, and furthermore, luteolin, apigenin, and chrysoeriol exhibited good anti-neuroinflammatory effects from both protein and mRNA levels. In summary, it is the first time to employ an integrative pharmacology strategy to delineate 22 constituents that may improve the pathological state of stroke with TRFS by regulating 27 corresponding targets, which may offer a highly efficient way to mine the scientific connotation of traditional Chinese medicine prescriptions. This study might be a supplement for the deficiency of the basic research of XLCQ.

Interaction between extracellular ATP5A1 and LPS alleviates LPS-induced neuroinflammation in mice

Neuroinflammation is one of the main causes of Alzheimer's disease (AD). The presence of Lipopolysaccharide (LPS) in senile plaques (SP) of AD suggests that it plays a role in AD pathogenesis. ATP5A1 (F1F0-ATP synthase F1 α subunit) is abundant in SP. Further, the protein has recently been found to have an anti-infection role in zebrafish embryos. In the present study, we observed that LPS levels were higher in the brains of APP/PS1 mice than in control mice, and LPS co-localised with ATP5A1 in amyloid plaques. The interaction of recombinant ATP5A1(rATP5A1) and LPS was evidenced by cellular thermal shift assay and enzyme-linked immunosorbent assay-based binding assay in vitro. Neuroinflammation in the brain of a mouse model was induced by intracerebroventricular injection of LPS. The addition of rATP5A1 relieved LPS-induced reduction of spontaneous locomotor ability, depressive-like behaviour, and working memory impairment. Furthermore, rATP5A1 suppressed the activation of astrocytes and microglia, IL-1β accumulation, and tau phosphorylation induced by LPS. Taken together, findings suggest that ATP5A1 is involved in the regulation of LPS-mediated neuroinflammation in AD.

Carbonyl cyanide 3-chlorophenylhydrazone induced the imbalance of mitochondrial homeostasis in the liver of Megalobrama amblycephala: A dynamic study

Carbonylcyanide-3-chlorophenylhydrazone (CCCP) is a protonophore, which causes uncoupling of proton gradient in the inner mitochondrial membrane, thus inhibiting the rate of ATP synthesis. However, this information is manly derived from mammals, while its effects on the mitochondrial homeostasis of aquatic animals are largely unknown. In this study, the mitochondrial homeostasis of a carp fish Megalobrama amblycephala was investigated systematically in a time-course manner by using CCCP. Fish was injected intraperitoneally with CCCP (1.8 mg/kg per body weight) and DMSO (control), respectively. The results showed that CCCP treatment induced hepatic mitochondrial oxidative stress, as was evidenced by the significantly increased MDA and PC contents coupled with the decreased SOD and MnSOD activities. Meanwhile, mitochondrial fission was up-regulated remarkably characterized by the increased transcriptions of Drp-1, Fis-1 and Mff. However, the opposite was true for mitochondrial fusion, as was indicative of the decreased transcriptions of Mfn-1, Mfn-2 and Opa-1. This consequently triggered mitophagy, as was supported by the accumulated mitochondrial autophagosomes and the increased protein levels of PINK1, Parkin, LC3-II and P62 accompanied by the increased LC3-II/LC3-I ratio. Mitochondrial biogenesis and function both decreased significantly addressed by the decreased activities of CS, SDH and complex I, IV and V, as well as the protein levels of PGC-1β coupled with the decreased transcriptions of TFAM, COX-1, COX-2 and ATP-6. Unlikely, DMSO treatment exerted little influence. Overall, CCCP treatment resulted in the imbalance of mitochondrial homeostasis in Megalobrama amblycephala by promoting mitochondrial oxidative stress, fission and mitophagy, but depressing mitochondrial fusion, biogenesis and function.

Metabolic energy conservation for fermentative product formation

Microbial production of bulk chemicals and biofuels from carbohydrates competes with low-cost fossil-based production. To limit production costs, high titres, productivities and especially high yields are required. This necessitates metabolic networks involved in product formation to be redox-neutral and conserve metabolic energy to sustain growth and maintenance. Here, we review the mechanisms available to conserve energy and to prevent unnecessary energy expenditure. First, an overview of ATP production in existing sugar-based fermentation processes is presented. Substrate-level phosphorylation (SLP) and the involved kinase reactions are described. Based on the thermodynamics of these reactions, we explore whether other kinase-catalysed reactions can be applied for SLP. Generation of ion-motive force is another means to conserve metabolic energy. We provide examples how its generation is supported by carbon-carbon double bond reduction, decarboxylation and electron transfer between redox cofactors. In a wider perspective, the relationship between redox potential and energy conservation is discussed. We describe how the energy input required for coenzyme A (CoA) and CO2 binding can be reduced by applying CoA-transferases and transcarboxylases. The transport of sugars and fermentation products may require metabolic energy input, but alternative transport systems can be used to minimize this. Finally, we show that energy contained in glycosidic bonds and the phosphate-phosphate bond of pyrophosphate can be conserved. This review can be used as a reference to design energetically efficient microbial cell factories and enhance product yield.

Molecular Pumps and Motors

Pumps and motors are essential components of the world as we know it. From the complex proteins that sustain our cells, to the mechanical marvels that power industries, much we take for granted is only possible because of pumps and motors. Although molecular pumps and motors have supported life for eons, it is only recently that chemists have made progress toward designing and building artificial forms of the microscopic machinery present in nature. The advent of artificial molecular machines has granted scientists an unprecedented level of control over the relative motion of components of molecules through the development of kinetically controlled, away-from-thermodynamic equilibrium chemistry. We outline the history of pumps and motors, focusing specifically on the innovations that enable the design and synthesis of the artificial molecular machines central to this Perspective. A key insight connecting biomolecular and artificial molecular machines is that the physical motions by which these machines carry out their function are unambiguously in mechanical equilibrium at every instant. The operation of molecular motors and pumps can be described by trajectory thermodynamics, a theory based on the work of Onsager, which is grounded on the firm foundation of the principle of microscopic reversibility. Free energy derived from thermodynamically non-equilibrium reactions kinetically favors some reaction pathways over others. By designing molecules with kinetic asymmetry, one can engineer potential landscapes to harness external energy to drive the formation and maintenance of geometries of component parts of molecules away-from-equilibrium, that would be impossible to achieve by standard synthetic approaches.

Mitochondrial redox and TCA cycle metabolite signaling in the heart

Mitochondria are essential signaling organelles that regulate a broad range of cellular processes and thereby heart function. Multiple mechanisms participate in the communication between mitochondria and the nucleus that maintain cardiomyocyte homeostasis, including mitochondrial reactive oxygen species (ROS) and metabolic shifts in TCA cycle metabolite availability. An increased rate of ROS generation can cause irreversible damage to the cell and proposed to be a leading cause of many pathologies, including accelerated aging and heart disease. Myocardial impairments are also characterised by specific coordinated metabolic changes and dysregulated inflammatory responses. Hence, the mitochondrial respiratory chain is an important mediator between health and disease in the heart. This review will first outline the sources of ROS in the heart, mitochondrial metabolite dynamics, and provide an overview of their implications for heart disease. In addition, we will concentrate our discussion around current cardioprotective strategies relevant to mitochondrial ROS. Thorough understanding of mitochondrial signaling and the complex interplay with vital signaling pathways in the heart might allow us to develop novel therapeutic approaches to cardiovascular disease.

Mechanisms of Energy Transduction by Charge Translocating Membrane Proteins

Life relies on the constant exchange of different forms of energy, i.e., on energy transduction. Therefore, organisms have evolved in a way to be able to harvest the energy made available by external sources (such as light or chemical compounds) and convert these into biological useable energy forms, such as the transmembrane difference of electrochemical potential (Δμ̃). Membrane proteins contribute to the establishment of Δμ̃ by coupling exergonic catalytic reactions to the translocation of charges (electrons/ions) across the membrane. Irrespectively of the energy source and consequent type of reaction, all charge-translocating proteins follow two molecular coupling mechanisms: direct- or indirect-coupling, depending on whether the translocated charge is involved in the driving reaction. In this review, we explore these two coupling mechanisms by thoroughly examining the different types of charge-translocating membrane proteins. For each protein, we analyze the respective reaction thermodynamics, electron transfer/catalytic processes, charge-translocating pathways, and ion/substrate stoichiometries.

Mitochondrial Homeostasis Mediates Lipotoxicity in the Failing Myocardium

Heart failure remains the most common cause of death in the industrialized world. In spite of new therapeutic interventions that are constantly being developed, it is still not possible to completely protect against heart failure development and progression. This shows how much more research is necessary to understand the underlying mechanisms of this process. In this review, we give a detailed overview of the contribution of impaired mitochondrial dynamics and energy homeostasis during heart failure progression. In particular, we focus on the regulation of fatty acid metabolism and the effects of fatty acid accumulation on mitochondrial structural and functional homeostasis.

Specificity and Plasticity of the Functional Ionome of Brassica napus and Triticum aestivum Subjected to Macronutrient Deprivation

The composition of the functional ionome was studied in Brassica napus and Triticum aestivum with respect to the response of 20 elements under macronutrient deprivation. Analysis of relative root contents showed that some nutrients, such as Fe, Ni, Cu, Na, V, and Co, were largely sequestered in roots. After 10 days of deprivation of each one of these 6 macronutrients, plant growth was similar to control plants, and this was probably the result of remobilization from roots (Mg and Ca) or old leaves (N, P, K, S). Some tissue concentrations and net nutrient uptakes into roots were either decreased or increased, revealing multiple interactions (93 in wheat, 66 in oilseed rape) that were common to both species (48) or were species specific. While some interactions have been previously described (increased uptake of Na under K deficiency; or increased uptake of Mo and Se under S deficiency), a number of new interactions were found and some key mechanisms underlying their action have been proposed from analysis of Arabidopsis mutants. For example, nitrate uptake seemed to be functionally linked to Na(influx, while the uptake of vanadium was probably mediated by sulfate transporters whose expression was stimulated during S deprivation.

Mitochondria are devoid of poly(ADP-ribose)polymerase-1, but harbor its product oligo(ADP-ribose)

There are conflicting data about localization of poly(ADP-ribose)polymerase-1 and its product poly(ADP-ribose) in mitochondria. To finally clarify the discussion, we investigated with biochemical and cell biological methods the potential presence of poly(ADP-ribose) polymerase-1 in these organelles. Our data show that endogenous and overexpressed poly(ADP-ribose)polymerase 1 is only localized to the nucleus with a clear exclusion of cytosolic compartments. In addition, highly purified mitochondria devoid of nuclear contaminations do not contain poly(ADP-ribose)polymerase-1. Although no poly(ADP-ribose)polymerase-1 enzyme is detectable in mitochondria, a shorter variant of its product poly(ADP-ribose) is present, associated specifically with a small subset of mitochondrial proteins as revealed by immunoprecipitation and protein fingerprint analysis. These proteins are located at key-points of the Krebs-cycle, are chaperones involved in mitochondrial functionality and quality-control, and are RNA-binding proteins important for transcript stability, respectively. Of note, despite the fact that especially poly(ADP-ribose)polymerase-1 is its own major target for modification, we could not detect this enzyme by mass spectrometry in these organelles. These data suggests a new way of targeted nuclear-mitochondrial signaling, mediated by nuclear poly(ADP-ribosyl)ation dependent on poly(ADP-ribose)polymerase-1.

Red LED Light Acts on the Mitochondrial Electron Chain of Mammalian Sperm via Light-Time Exposure-Dependent Mechanisms

This work analyzes the effects of red LED light on mammalian sperm mitochondrial function, using the pig as an animal model. Liquid-stored pig semen was stimulated with red-light for 1, 5 and 10 min in the presence or absence of oligomycin A, a specific inhibitor of mitochondrial ATP synthase, or carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP), a specific disruptor of mitochondrial electron chain. Whereas exposure for 1 and 5 min significantly (p < 0.05) decreased total motility and intracellular ATP levels, irradiation for 10 min induced the opposite effect. Oligomycin A abolished the light-effects on intracellular ATP levels, O2 consumption and mitochondrial membrane potential, whereas compared to non-irradiated samples, FCCP significantly (p < 0.05) increased O2 consumption when sperm were irradiated for 1 min. Both oligomycin A and FCCP significantly (p < 0.05) decreased total motility. Red-light increased cytochrome c oxidase activity with a maximal effect after 5 min of irradiation, which was abolished by both oligomycin A and FCCP. In conclusion, red-light modulates sperm mitochondrial function via electron chain activity in an exposition, time-dependent manner.

Effects of Fluoride Long-Term Exposure over the Cerebellum: Global Proteomic Profile, Oxidative Biochemistry, Cell Density, and Motor Behavior Evaluation

Although the literature does not provide evidence of health risks from exposure to fluoride (F) in therapeutic doses, questions remain about the effects of long-term and high-dose use on the function of the central nervous system. The objective of this study was to investigate the effect of long-term exposure to F at levels similar to those found in areas of artificial water fluoridation and in areas of endemic fluorosis on biochemical, proteomic, cell density, and functional parameters associated with the cerebellum. For this, mice were exposed to water containing 10 mg F/L or 50 mg F/L (as sodium fluoride) for 60 days. After the exposure period, the animals were submitted to motor tests and the cerebellum was evaluated for fluoride levels, antioxidant capacity against peroxyl radicals (ACAP), lipid peroxidation (MDA), and nitrite levels (NO). The proteomic profile and morphological integrity were also evaluated. The results showed that the 10 mg F/L dose was able to decrease the ACAP levels, and the animals exposed to 50 mg F/L presented lower levels of ACAP and higher levels of MDA and NO. The cerebellar proteomic profile in both groups was modulated, highlighting proteins related to the antioxidant system, energy production, and cell death, however no neuronal density change in cerebellum was observed. Functionally, the horizontal exploratory activity of both exposed groups was impaired, while only the 50 mg F/L group showed significant changes in postural stability. No motor coordination and balance impairments were observed in both groups. Our results suggest that fluoride may impair the cerebellar oxidative biochemistry, which is associated with the proteomic modulation and, although no morphological impairment was observed, only the highest concentration of fluoride was able to impair some cerebellar motor functions.

Oligomycins inhibit Magnaporthe oryzae Triticum and suppress wheat blast disease

Oligomycins are macrolide antibiotics, produced by Streptomyces spp. that show antagonistic effects against several microorganisms such as bacteria, fungi, nematodes and the oomycete Plasmopara viticola. Conidiogenesis, germination of conidia and formation of appressoria are determining factors pertaining to pathogenicity and successful diseases cycles of filamentous fungal phytopathogens. The goal of this research was to evaluate the in vitro suppressive effects of two oligomycins, oligomycin B and F along with a commercial fungicide Nativo® 75WG on hyphal growth, conidiogenesis, conidial germination, and appressorial formation of the wheat blast fungus, Magnaporthe oryzae Triticum (MoT) pathotype. We also determined the efficacy of these two oligomycins and the fungicide product in vivo in suppressing wheat blast with a detached leaf assay. Both oligomycins suppressed the growth of MoT mycelium in a dose dependent manner. Between the two natural products, oligomycin F provided higher inhibition of MoT hyphal growth compared to oligomycin B with a minimum inhibitory concentration of 0.005 and 0.05 μg/disk, respectively. The application of the compounds completely halted conidial formation of the MoT mycelium in agar medium. Further bioassays showed that these compounds significantly inhibited MoT conidia germination and induced lysis. The compounds also caused abnormal germ tube formation and suppressed appressorial formation of germinated spores. Interestingly, the application of these macrolides significantly inhibited wheat blast on detached leaves of wheat. This is the first report on the inhibition of mycelial growth, conidiogenesis, germination of conidia, deleterious morphological changes in germinated conidia, and suppression of blast disease of wheat by oligomycins from Streptomyces spp. Further study is needed to unravel the precise mode of action of these natural compounds and consider them as biopesticides for controlling wheat blast.

Effects of adenosine triphosphate on vandetanib induced skin damage in rats

PURPOSE

Vandetanib is a wide spectrum tyrosine kinase inhibitor used for the treatment of metastatic medullary thyroid cancer (MTC) and various other cancer types. Although it is usually well-tolerated ıt has been linked to a variety of severe dermatologic reactions. Our study aimed was to investigate adenosine 5'-triphosphate (ATP) on vandetanib-induced skin damage.

MATERIALS AND METHODS

A total number of 18 rats were divided into three equal groups as vandetanib group (VDB), vandetanib plus ATP group (VAT), and healthy group (HG); 25 mg/kg ATP was injected intraperitoneally (ip) to the VAT group. Normal saline was given to the HG and VDB groups as solvent via intraperitoneally. One hour later, 25 mg/kg vandetanib was applied orally via an orogastric catheter in the VAT and VDB groups. This procedure was repeated once daily for 4 weeks. After that period, all animals were sacrificed and their skin tissues removed. Malondialdehyde (MDA), total glutathione (tGSH), total oxidant status (TOS), total antioxidant status (TAS) levels in rats' skin tissues were evaluated with histopathological analyses.

RESULTS

MDA and TOS levels measured higher in the VDB group compared to the VAT and HG groups (p < 0.001). tGSH and TAS levels of the VDB group measured lower than the VAT and HG groups (p < 0.001). The structure and morphology of skin tissue were normal in the control group. In the VDB group, skin tissue damage with thinner epitelium, ruptured and degenerated hair follicles, abnormal accumulation of abnormal keratin on the epithelium and oedematous areas in the dermis was observed. In the VAT group, these findings were significantly improved.

CONCLUSION

We demonstrated that adenosine triphosphate can prevent vandetanib-induced skin toxicity in rats for the first time. The promising results denote that further studies testing this agent in other animal models and in humans are warranted.

Enhanced exopolysaccharide production in submerged fermentation of Ganoderma lucidum by Tween 80 supplementation

Bioactive polysaccharides extracted from Ganoderma lucidum (G. lucidum) have been widely applied in food and medicine for their multiple functions. In this study, G. lucidum exopolysaccharide (EPS) production in submerged fermentation was stimulated by Tween 80. The addition of 0.25% Tween 80 on day 3 gave a maximum production of mycelial biomass and EPS, with an increase of 19.76 and 137.50%, respectively. Analysis of fermentation kinetics showed that glucose was consumed faster after adding Tween 80, while the expression of EPS biosynthesis-related genes and ATP generation were greatly improved. Moreover, Tween 80 resulted in the significant accumulation of reactive oxygen species and increased cell membrane and cell wall permeability. The EPS from Tween 80-containing medium had higher contents of carbohydrate and uronic acid, lower molecular weight, and higher antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals than those of EPS produced in the absence of Tween 80. This study provides further evidence to clarify the stimulatory effects of Tween 80 in fermentation and provides a guide for the production of bioactive G. lucidum EPS.

Protective effect of adenosine triphosphate against sunitinib-related skin damage in rats

Cutaneous side effects associated with sunitinib use are a major problem in patients receiving cancer treatment. The aim of this study was to investigate the protective effect of adenosine triphosphate (ATP) against possible skin damage resulting from sunitinib use in rats. Thirty Albino Winstar rats were divided into the following three groups: healthy controls (HCs, n = 10), sunitinib (SUN, n = 10), and sunitinib + ATP (SAT, n = 10). ATP was injected intraperitoneally at a dose of 2 mg/kg. One hour subsequent to the administration of ATP and 0.9% NaCl, the SAT and SUN groups were orally administered a dose of 25 mg/kg sunitinib to the stomach. Macroscopic evaluation of the skin indicated lower levels of skin damage in the SAT group than in the SUN group. As an indicator of oxidative stress, malondialdehyde (MDA), total oxidant status (TOS), and oxidative stress index (OSI) levels were significantly higher in the SUN group than in the HC group, while total glutathione (tGSH) and total antioxidant status (TAS) levels were significantly lower. However, MDA, TOS, and OSI levels were significantly lower in the SAT group than in the SUN group, while tGSH and TAS levels were significantly higher. Histopathological examination revealed keratin plugs with edema, vasopathology, and inflammatory cell infiltration in the SUN group. The SAT group showed less necrotic epithelium, keratin plugs, edema, and vasopathology than the SUN group. ATP can be effective in preventing skin damage caused by sunitinib use by reducing oxidative stress.

C3a receptor blockade protects podocytes from injury in diabetic nephropathy

Renal activation of the complement system has been described in patients with diabetic nephropathy (DN), although its pathological relevance is still ill-defined. Here, we studied whether glomerular C3a, generated by uncontrolled complement activation, promotes podocyte damage, leading to proteinuria and renal injury in mice with type 2 diabetes. BTBR ob/ob mice exhibited podocyte loss, albuminuria, and glomerular injury accompanied by C3 deposits and increased C3a and C3a receptor (C3aR) levels. Decreased glomerular nephrin and α-actinin4 expression, coupled with integrin-linked kinase induction, were also observed. Treatment of DN mice with a C3aR antagonist enhanced podocyte density and preserved their phenotype, limiting proteinuria and glomerular injury. Mechanistically, ultrastructural and functional mitochondrial alterations, accompanied by downregulation of antioxidant superoxide dismutase 2 (SOD2) and increased protein oxidation, occurred in podocytes and were normalized by C3aR blockade. In cultured podocytes, C3a induced cAMP-dependent mitochondrial fragmentation. Alterations of mitochondrial membrane potential, SOD2 expression, and energetic metabolism were also found in response to C3a. Notably, C3a-induced podocyte motility was inhibited by SS-31, a peptide with mitochondrial protective effects. These data indicate that C3a blockade represents a potentially novel therapeutic strategy in DN for preserving podocyte integrity through the maintenance of mitochondrial functions.

Murburn concept: a paradigm shift in cellular metabolism and physiology

Two decades of evidence-based exploratory pursuits in heme-flavin enzymology led to the formulation of a new biological electron/moiety transfer paradigm, called murburn concept. Murburn is a novel literary abstraction from "mured burning" or "mild unrestricted burning". This concept was invoked to explain the longstanding conundrum of maverick physiological dose responses and also applied to remodel the prevailing understanding of drug metabolism and cellular respiration. A conglomeration of simple ideas grounded in the known principles of thermodynamics and reaction chemistry, murburn concept invokes catalytic/functional roles for diffusible reactive species or radicals. Hitherto, diffusible reactive species were primarily seen as toxic agents of chaos, non-conducible to the maintenance of life-order. Since the murburn paradigm offers a distinctly different perspective for several biological phenomena, researchers holding conventional views of cellular metabolism pose a direct conflict of interests to the advancement of murburn concept. Murburn schemes are poised to integrate numerous metabolic motifs with holistic physiological outcomes; redefining pursuits in biology and medicine. To advance this agenda, I present a brief account of murburn concept and point out how redundant ideas are still advocated in some prestigious journals.

Using the NIH symptom science model to understand fatigue and mitochondrial bioenergetics

The symptom of fatigue is prevalent among patients with chronic diseases and conditions such as congestive heart failure and cancer. It has a significant debilitating impact on patients' physical health, quality of life, and well-being. Early detection and appropriate assessment of fatigue is essential for diagnosing, treating, and monitoring disease progression. However, it is often challenging to manage the symptom of fatigue without first investigating the underlying biological mechanisms. In this narrative review, we conceptualize the symptom of fatigue and its relationship with mitochondrial bioenergetics using the National Institute of Health Symptom Science Model (NIH-SSM). In particular, we discuss mental and physical measures to assess fatigue, the importance of adenosine triphosphate (ATP) in cellular and organ functions, and how impaired ATP production contributes to fatigue. Specific methods to measure ATP are described. Recommendations are provided concerning how to integrate biological mechanisms with the symptom of fatigue for future research and clinical practice to help alleviate symptoms and improve patients' quality of life.

Mitochondrial Bioenergetics and Dynamics in Secretion Processes

Secretion is an energy consuming process that plays a relevant role in cell communication and adaptation to the environment. Among others, endocrine cells producing hormones, immune cells producing cytokines or antibodies, neurons releasing neurotransmitters at synapsis, and more recently acknowledged, senescent cells synthesizing and secreting multiple cytokines, growth factors and proteases, require energy to successfully accomplish the different stages of the secretion process. Calcium ions (Ca²⁺) act as second messengers regulating secretion in many of these cases. In this setting, mitochondria appear as key players providing ATP by oxidative phosphorylation, buffering Ca²⁺ concentrations and acting as structural platforms. These tasks also require the concerted actions of the mitochondrial dynamics machinery. These proteins mediate mitochondrial fusion and fission, and are also required for transport and tethering of mitochondria to cellular organelles where the different steps of the secretion process take place. Herein we present a brief overview of mitochondrial energy metabolism, mitochondrial dynamics, and the different steps of the secretion processes, along with evidence of the interaction between these pathways. We also analyze the role of mitochondria in secretion by different cell types in physiological and pathological settings.

Important Role of Mitochondria and the Effect of Mood Stabilizers on Mitochondrial Function

Mitochondria primarily serve as source of cellular energy through the Krebs cycle and β-oxidation to generate substrates for oxidative phosphorylation. Redox reactions are used to transfer electrons through a gradient to their final acceptor, oxygen, and to pump hydrogen protons into the intermembrane space. Then, ATP synthase uses the electrochemical gradient to generate adenosine triphosphate (ATP). During these processes, reactive oxygen species (ROS) are generated. ROS are highly reactive molecules with important physiological functions in cellular signaling. Mitochondria play a crucial role in intracellular calcium homeostasis and serve as transient calcium stores. High levels of both, ROS and free cytosolic calcium, can damage mitochondrial and cellular structures and trigger apoptosis. Impaired mitochondrial function has been described in many psychiatric diseases, including mood disorders, in terms of lowered mitochondrial membrane potential, suppressed ATP formation, imbalanced Ca2+ levels and increased ROS levels. In vitro models have indicated that mood stabilizers affect mitochondrial respiratory chain complexes, ROS production, ATP formation, Ca2+ buffering and the antioxidant system. Most studies support the hypothesis that mitochondrial dysfunction is a primary feature of mood disorders. The precise mechanism of action of mood stabilizers remains unknown, but new mitochondrial targets have been proposed for use as mood stabilizers and mitochondrial biomarkers in the evaluation of therapy effectiveness.

Identification of ATP synthase α subunit as a new maternal factor capable of protecting zebrafish embryos from bacterial infection

Previous studies have shown that ATP synthase α subunit (ATP5A1) plays multiple roles, but our understanding of its biologic functions remains poor and incomprehensive. Here, we clearly demonstrated that zebrafish ATP5A1 was a newly characterized lipoteichoic acid (LTA)- and LPS-binding protein abundantly stored in the eggs and embryos of zebrafish. Zebrafish ATP5A1 acted not only as a pattern recognition receptor, capable of identifying LTA and LPS, but also as an effector molecule, capable of inhibiting the growth of both gram-positive and -negative bacteria. ATP5A1 could disrupt the bacterial membranes by a combined action of membrane depolarization and permeabilization. We also found that the N-terminal 65 residues were critical for the antibacterial activity of zebrafish ATP5A1. In particular, we showed that microinjection of exogenous recombinant (r)ATP5A1 into early embryos could promote their resistance against pathogenic Aeromonas hydrophila challenge, and this pathogen-resistant activity was markedly reduced by the coinjection of anti-ATP5A1 antibody or by the knockdown with morpholino for atp5a1 but not by the coinjection of anti-actin antibody. Moreover, each egg/embryo contains a sufficient amount of ATP5A1 in vivo to kill A. hydrophila. Furthermore, the N-terminal 65 residues 1-65 of ATP5A1 α subunit (rA_1-65) with in vitro antibacterial activity also promoted the resistance of embryos against A. hydrophila, but the N-terminal 69 residues 66-134 (rA_66-134) or C-terminal residues 135-551 (rA_135-551) of ATP5A1 α subunit without in vitro antibacterial activity did not. Finally, we showed that the antibacterial activity of the N-terminal 65 residues of ATP5A1 α subunit was conserved throughout animal evolution. Collectively, these results indicate that ATP5A1 is a novel maternal immunocompetent factor that can protect the early embryos of zebrafish from bacterial infection. This work also provides a new viewpoint for understanding the biologic roles of ATP5A1, which is ubiquitously present in animals.-Ni, S., Zhou, Y., Chen, Y., Du, X., Zhang, S. Identification of ATP synthase α subunit as a new maternal factor capable of protecting zebrafish embryos from bacterial infection.

Genome-Wide Identification and Characterization of Long Noncoding RNAs of Brown to White Adipose Tissue Transformation in Goats

Long noncoding RNAs (lncRNAs) play an important role in the thermogenesis and energy storage of brown adipose tissue (BAT). However, knowledge of the cellular transition from BAT to white adipose tissue (WAT) and the potential role of lncRNAs in goat adipose tissue remains largely unknown. In this study, we analyzed the transformation from BAT to WAT using histological and uncoupling protein 1 (UCP1) gene analyses. Brown adipose tissue mainly existed within the goat perirenal fat at 1 day and there was obviously a transition from BAT to WAT from 1 day to 1 year. The RNA libraries constructed from the perirenal adipose tissues of 1 day, 30 days, and 1 year goats were sequenced. A total number of 21,232 lncRNAs from perirenal fat were identified, including 5393 intronic-lncRNAs and 3546 antisense-lncRNAs. Furthermore, a total of 548 differentially expressed lncRNAs were detected across three stages (fold change ≥ 2.0, false discovery rate (FDR) < 0.05), and six lncRNAs were validated by qPCR. Furthermore, trans analysis found lncRNAs that were transcribed close to 890 protein-coding genes. Additionally, a coexpression network suggested that 4519 lncRNAs and 5212 mRNAs were potentially in trans-regulatory relationships (r > 0.95 or r < -0.95). In addition, Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses showed that the targeted genes were involved in the biosynthesis of unsaturated fatty acids, fatty acid elongation and metabolism, the citrate cycle, oxidative phosphorylation, the mitochondrial respiratory chain complex, and AMP-activated protein kinase (AMPK) signaling pathways. The present study provides a comprehensive catalog of lncRNAs involved in the transformation from BAT to WAT and provides insight into understanding the role of lncRNAs in goat brown adipogenesis.