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1.
Gene ; 806: 145929, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34461150

RESUMO

The body color of Neocaridina denticulate sinensis is a compelling phenotypic trait, in which a cascade of carotenoid metabolic processes plays an important role. The study was conducted to compare the transcriptome of cephalothoraxes among three pigmentation phenotypes (red, blue, and chocolate) of N. denticulate sinensis. The purpose of this study was to explore the candidate genes associated with different colors of N. denticulate sinensis. Nine cDNA libraries in three groups were constructed from the cephalothoraxes of shrimps. After assembly, 75022 unigenes were obtained in total with an average length of 1026 bp and N50 length of 1876 bp. There were 45977, 25284, 23605, 21913 unigenes annotated in the Nr, Swissprot, KOG, and KEGG databases, respectively. Differential expression analysis revealed that there were 829, 554, and 3194 differentially expressed genes (DEGs) in RD vs BL, RD vs CH, and BL vs CH, respectively. These DEGs may play roles in the absorption, transport, and metabolism of carotenoids. We also emphasized that electron transfer across the inner mitochondrial membrane (IMM) was a key process in pigment metabolism. In addition, a total of 6328 simple sequence repeats (SSRs) were also detected in N. denticulate sinensis. The results laid a solid foundation for further research on the molecular mechanism of integument pigmentation in the crustacean and contributed to developing more attractive aquatic animals.


Assuntos
Proteínas de Artrópodes/genética , Carotenoides/metabolismo , Decápodes/genética , Pigmentação/genética , Transcriptoma , Animais , Organismos Aquáticos , Proteínas de Artrópodes/classificação , Proteínas de Artrópodes/metabolismo , Transporte Biológico , Cor , Bases de Dados Genéticas , Decápodes/anatomia & histologia , Decápodes/metabolismo , Água Doce , Regulação da Expressão Gênica , Biblioteca Gênica , Ontologia Genética , Repetições de Microssatélites , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Anotação de Sequência Molecular , Característica Quantitativa Herdável
2.
Nat Commun ; 12(1): 4769, 2021 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-34362905

RESUMO

Beyond its role in mitochondrial bioenergetics, Coenzyme Q (CoQ, ubiquinone) serves as a key membrane-embedded antioxidant throughout the cell. However, how CoQ is mobilized from its site of synthesis on the inner mitochondrial membrane to other sites of action remains a longstanding mystery. Here, using a combination of Saccharomyces cerevisiae genetics, biochemical fractionation, and lipid profiling, we identify two highly conserved but poorly characterized mitochondrial proteins, Ypl109c (Cqd1) and Ylr253w (Cqd2), that reciprocally affect this process. Loss of Cqd1 skews cellular CoQ distribution away from mitochondria, resulting in markedly enhanced resistance to oxidative stress caused by exogenous polyunsaturated fatty acids, whereas loss of Cqd2 promotes the opposite effects. The activities of both proteins rely on their atypical kinase/ATPase domains, which they share with Coq8-an essential auxiliary protein for CoQ biosynthesis. Overall, our results reveal protein machinery central to CoQ trafficking in yeast and lend insights into the broader interplay between mitochondria and the rest of the cell.


Assuntos
Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Ubiquinona/análogos & derivados , Ubiquinona/metabolismo , Antioxidantes/metabolismo , Lipídeos , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Proteínas Mitocondriais/metabolismo , Estresse Oxidativo , Fosfotransferases/metabolismo , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética
3.
Nat Commun ; 12(1): 4980, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34404792

RESUMO

Proximity labeling (PL) with genetically-targeted promiscuous enzymes has emerged as a powerful tool for unbiased proteome discovery. By combining the spatiotemporal specificity of PL with methods for functional protein enrichment, we show that it is possible to map specific protein subclasses within distinct compartments of living cells. In particular, we develop a method to enrich subcompartment-specific RNA binding proteins (RBPs) by combining peroxidase-catalyzed PL with organic-aqueous phase separation of crosslinked protein-RNA complexes ("APEX-PS"). We use APEX-PS to generate datasets of nuclear, nucleolar, and outer mitochondrial membrane (OMM) RBPs, which can be mined for novel functions. For example, we find that the OMM RBP SYNJ2BP retains specific nuclear-encoded mitochondrial mRNAs at the OMM during translation stress, facilitating their local translation and import of protein products into the mitochondrion during stress recovery. Functional PL in general, and APEX-PS in particular, represent versatile approaches for the discovery of proteins with novel function in specific subcellular compartments.


Assuntos
RNA Mensageiro/metabolismo , RNA Mitocondrial/metabolismo , Proteínas de Ligação a RNA/metabolismo , Técnicas de Inativação de Genes , Células HEK293 , Humanos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Fosforilação , Proteoma/metabolismo , Proteômica , RNA Mensageiro/genética , Proteínas de Ligação a RNA/genética
4.
Molecules ; 26(16)2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34443546

RESUMO

Recent studies found that short-chain fatty acids (SCFAs), which are produced through bacterial fermentation in the gastrointestinal tract, have oncoprotective effects against cervical cancer. The most common SCFAs that are well known include acetic acid, butyric acid, and propionic acid, among which propionic acid (PA) has been reported to induce apoptosis in HeLa cells. However, the mechanism in which SCFAs suppress HeLa cell viability remain poorly understood. Our study aims to provide a more detailed look into the mechanism of PA in HeLa cells. Flow cytometry analysis revealed that PA induces reactive oxygen species (ROS), leading to the dysfunction of the mitochondrial membrane. Moreover, PA inhibits NF-κB and AKT/mTOR signaling pathways and induces LC3B protein levels, resulting in autophagy. PA also increased the sub-G1 cell population that is characteristic of cell death. Therefore, the results of this study propose that PA inhibits HeLa cell viability through a mechanism mediated by the induction of autophagy. The study also suggests a new approach for cervical cancer therapeutics.


Assuntos
Antineoplásicos/farmacologia , Propionatos/farmacologia , Neoplasias do Colo do Útero/patologia , Antineoplásicos/química , Autofagia/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Feminino , Células HeLa , Humanos , Membranas Mitocondriais/efeitos dos fármacos , Membranas Mitocondriais/metabolismo , NF-kappa B/metabolismo , Propionatos/química , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Neoplasias do Colo do Útero/metabolismo
5.
Int J Mol Sci ; 22(16)2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34445139

RESUMO

Recent evidence pinpoints extracellular vesicles (EVs) as key players in intercellular communication. Given the importance of cholesterol and sphingomyelin in EV biology, and the relevance of mitochondria-associated endoplasmic reticulum membranes (MAMs) in cholesterol/sphingomyelin homeostasis, we evaluated if MAMs and sphingomyelinases (SMases) could participate in ethanol-induced EV release. EVs were isolated from the extracellular medium of BV2 microglia treated or not with ethanol (50 and 100 mM). Radioactive metabolic tracers combined with thin layer chromatography were used as quantitative methods to assay phospholipid transfer, SMase activity and cholesterol uptake/esterification. Inhibitors of SMase (desipramine and GW4869) and MAM (cyclosporin A) activities were also utilized. Our data show that ethanol increases the secretion and inflammatory molecule concentration of EVs. Ethanol also upregulates MAM activity and alters lipid metabolism by increasing cholesterol uptake, cholesterol esterification and SMase activity in microglia. Notably, the inhibition of either SMase or MAM activity prevented the ethanol-induced increase in EV secretion. Collectively, these results strongly support a lipid-driven mechanism, specifically via SMases and MAM, to explain the effect of ethanol on EV secretion in glial cells.


Assuntos
Retículo Endoplasmático/efeitos dos fármacos , Etanol/farmacologia , Vesículas Extracelulares/efeitos dos fármacos , Metabolismo dos Lipídeos/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Membranas Mitocondriais/efeitos dos fármacos , Esfingomielina Fosfodiesterase/metabolismo , Compostos de Anilina/farmacologia , Animais , Compostos de Benzilideno/farmacologia , Células Cultivadas , Colesterol/metabolismo , Ciclosporina/farmacologia , Retículo Endoplasmático/metabolismo , Vesículas Extracelulares/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microglia/efeitos dos fármacos , Microglia/metabolismo , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Fosfolipídeos/metabolismo
6.
Molecules ; 26(13)2021 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-34279427

RESUMO

The functioning of mitochondria and their biogenesis are largely based on the proper function of the mitochondrial outer membrane channels, which selectively recognise and import proteins but also transport a wide range of other molecules, including metabolites, inorganic ions and nucleic acids. To date, nine channels have been identified in the mitochondrial outer membrane of which at least half represent the mitochondrial protein import apparatus. When compared to the mitochondrial inner membrane, the presented channels are mostly constitutively open and consequently may participate in transport of different molecules and contribute to relevant changes in the outer membrane permeability based on the channel conductance. In this review, we focus on the channel structure, properties and transported molecules as well as aspects important to their modulation. This information could be used for future studies of the cellular processes mediated by these channels, mitochondrial functioning and therapies for mitochondria-linked diseases.


Assuntos
Canais Iônicos/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Mitocôndrias/patologia , Doenças Mitocondriais/patologia , Membranas Mitocondriais/metabolismo , Humanos , Mitocôndrias/metabolismo , Doenças Mitocondriais/metabolismo , Transporte Proteico
7.
Int J Mol Sci ; 22(14)2021 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-34298976

RESUMO

The voltage-dependent anion channel (VDAC) is the primary regulating pathway of water-soluble metabolites and ions across the mitochondrial outer membrane. When reconstituted into lipid membranes, VDAC responds to sufficiently large transmembrane potentials by transitioning to gated states in which ATP/ADP flux is reduced and calcium flux is increased. Two otherwise unrelated cytosolic proteins, tubulin, and α-synuclein (αSyn), dock with VDAC by a novel mechanism in which the transmembrane potential draws their disordered, polyanionic C-terminal domains into and through the VDAC channel, thus physically blocking the pore. For both tubulin and αSyn, the blocked state is observed at much lower transmembrane potentials than VDAC gated states, such that in the presence of these cytosolic docking proteins, VDAC's sensitivity to transmembrane potential is dramatically increased. Remarkably, the features of the VDAC gated states relevant for bioenergetics-reduced metabolite flux and increased calcium flux-are preserved in the blocked state induced by either docking protein. The ability of tubulin and αSyn to modulate mitochondrial potential and ATP production in vivo is now supported by many studies. The common physical origin of the interactions of both tubulin and αSyn with VDAC leads to a general model of a VDAC inhibitor, facilitates predictions of the effect of post-translational modifications of known inhibitors, and points the way toward the development of novel therapeutics targeting VDAC.


Assuntos
Ânions/metabolismo , Respiração Celular/fisiologia , Proteínas Intrinsicamente Desordenadas/fisiologia , Membranas Mitocondriais/efeitos dos fármacos , Tubulina (Proteína)/fisiologia , Canais de Ânion Dependentes de Voltagem/antagonistas & inibidores , alfa-Sinucleína/fisiologia , Sequência de Aminoácidos , Animais , Cálcio/metabolismo , Respiração Celular/efeitos dos fármacos , Fluoresceínas/química , Humanos , Proteínas Intrinsicamente Desordenadas/química , Ativação do Canal Iônico/efeitos dos fármacos , Ativação do Canal Iônico/fisiologia , Cinética , Membranas Mitocondriais/metabolismo , Modelos Moleculares , Concentração Osmolar , Cloreto de Potássio/farmacologia , Conformação Proteica , Mapeamento de Interação de Proteínas , Processamento de Proteína Pós-Traducional , Transporte Proteico , Alinhamento de Sequência , Ácidos Sulfônicos/química , Tubulina (Proteína)/química , Canais de Ânion Dependentes de Voltagem/química , Canais de Ânion Dependentes de Voltagem/fisiologia , alfa-Sinucleína/química
8.
Nat Commun ; 12(1): 4583, 2021 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-34321484

RESUMO

Voltage dependent anion channel 2 (VDAC2) is an outer mitochondrial membrane porin known to play a significant role in apoptosis and calcium signaling. Abnormalities in calcium homeostasis often leads to electrical and contractile dysfunction and can cause dilated cardiomyopathy and heart failure. However, the specific role of VDAC2 in intracellular calcium dynamics and cardiac function is not well understood. To elucidate the role of VDAC2 in calcium homeostasis, we generated a cardiac ventricular myocyte-specific developmental deletion of Vdac2 in mice. Our results indicate that loss of VDAC2 in the myocardium causes severe impairment in excitation-contraction coupling by altering both intracellular and mitochondrial calcium signaling. We also observed adverse cardiac remodeling which progressed to severe cardiomyopathy and death. Reintroduction of VDAC2 in 6-week-old knock-out mice partially rescued the cardiomyopathy phenotype. Activation of VDAC2 by efsevin increased cardiac contractile force in a mouse model of pressure-overload induced heart failure. In conclusion, our findings demonstrate that VDAC2 plays a crucial role in cardiac function by influencing cellular calcium signaling. Through this unique role in cellular calcium dynamics and excitation-contraction coupling VDAC2 emerges as a plausible therapeutic target for heart failure.


Assuntos
Cálcio/metabolismo , Cardiomiopatia Dilatada/metabolismo , Homeostase , Canal de Ânion 2 Dependente de Voltagem/genética , Canal de Ânion 2 Dependente de Voltagem/metabolismo , Animais , Apoptose , Sinalização do Cálcio , Cardiomiopatia Dilatada/mortalidade , Insuficiência Cardíaca/metabolismo , Camundongos , Camundongos Knockout , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Contração Miocárdica , Miócitos Cardíacos/metabolismo , Transcriptoma
9.
Int J Mol Sci ; 22(11)2021 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-34198873

RESUMO

Nicotinamide nucleotide transhydrogenase (NNT) is a proton pump in the inner mitochondrial membrane that generates reducing equivalents in the form of NAPDH, which can be used for anabolic pathways or to remove reactive oxygen species (ROS). A number of studies have linked NNT dysfunction to cardiomyopathies and increased risk of atherosclerosis; however, biallelic mutations in humans commonly cause a phenotype of adrenal insufficiency, with rare occurrences of cardiac dysfunction and testicular tumours. Here, we compare the transcriptomes of the hearts, adrenals and testes from three mouse models: the C57BL/6N, which expresses NNT; the C57BL/6J, which lacks NNT; and a third mouse, expressing the wild-type NNT sequence on the C57BL/6J background. We saw enrichment of oxidative phosphorylation genes in the C57BL/B6J in the heart and adrenal, possibly indicative of an evolved response in this substrain to loss of Nnt. However, differential gene expression was mainly driven by mouse background with some changes seen in all three tissues, perhaps reflecting underlying genetic differences between the C57BL/B6J and -6N substrains.


Assuntos
Aterosclerose/genética , Cardiomiopatias/genética , Miocárdio/metabolismo , NADP Trans-Hidrogenase Específica para A ou B/genética , Fosforilação Oxidativa , Glândulas Suprarrenais/metabolismo , Animais , Aterosclerose/metabolismo , Aterosclerose/patologia , Cardiomiopatias/patologia , Modelos Animais de Doenças , Regulação da Expressão Gênica/genética , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/genética , Membranas Mitocondriais/metabolismo , Proteínas Mitocondriais/genética , Fenótipo , Espécies Reativas de Oxigênio/metabolismo , Testículo/metabolismo
10.
FASEB J ; 35(8): e21764, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34245631

RESUMO

The size of the permeability transition pore (PTP) is accepted to be ≤1.5 kDa. However, different authors reported values from 650 to 4000 Da. The present study is focused on the variability of the average PTP size in and between mitochondrial samples, its reasons and relations with PTP dynamics. Measurement of PTP size by the standard method revealed its 500 Da-range variability between mitochondrial samples. Sequential measurements in the same sample showed that the PTP size tends to grow with time and Ca2+ concentration. Selective damage to the mitochondrial outer membrane (MOM) reduced the apparent PTP size by ~200-300 Da. Hypotonic and hypertonic osmotic shock and partial removal of the MOM with the preservation of the mitochondrial inner membrane intactness decreased the apparent PTP size by ~50%. We developed an approach to continuous monitoring of the PTP size that revealed the existence of stable PTP states with different pore sizes (~700, 900-1000, ~1350, 1700-1800, and 2100-2200 Da) and transitions between them. The transitions were accelerated by elevating the Ca2+ concentration, temperature, and osmotic pressure, which demonstrates an increased capability of PTP to accommodate to large molecules (plasticity). Cyclosporin A inhibited the transitions between states. The analysis of PTP size dynamics in osmotically shocked mitochondria and mitoplasts confirmed the importance of the MOM for the stabilization of PTP structure. Thus, this approach provides a new tool for PTP studies and the opportunity to reconcile data on the PTP size and mitochondrial megachannel conductance.


Assuntos
Cálcio/química , Mitocôndrias/química , Proteínas de Transporte da Membrana Mitocondrial/química , Membranas Mitocondriais/química , Humanos , Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Membranas Mitocondriais/metabolismo
11.
Methods Mol Biol ; 2275: 363-378, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34118050

RESUMO

In the last decades, membrane contact sites (MCSs) have been the object of intense investigation in different fields of cell physiology and pathology and their importance for the correct functioning of the cell is now widely recognized. MCS between any known intercellular organelles, including endoplasmic reticulum (ER), mitochondria, Golgi, endosomes, peroxisomes, lysosomes, lipid droplets, and the plasma membrane (PM), have been largely documented and in some cases the molecules responsible for the tethering also identified. They represent specific membrane hubs where a tightly coordinated exchange of ions, lipids, nutrients, and factors required to maintain proper cellular homeostasis takes place. Their delicate, dynamic, and sometimes elusive nature prevented and/or delayed the development of tools to easily image interorganelle proximity under physiological conditions and in living organisms. Nowadays, this aspect received great momentum due to the finding that MCSs' dysregulation is involved in several pathological conditions. We have recently developed modular, split-GFP-based contact site sensors (SPLICS) engineered to fluoresce when homo- and heterotypic juxtapositions between ER and mitochondria occur over a range of specific distances. Here we describe in detail, by highlighting strengths and weaknesses, the use and the application of these novel genetically encoded SPLICS sensors and how to properly quantify short- and long-range ER-mitochondria interactions.


Assuntos
Membrana Celular/metabolismo , Retículo Endoplasmático/metabolismo , Proteínas de Fluorescência Verde/metabolismo , Mitocôndrias/metabolismo , Células HeLa , Humanos , Membranas Mitocondriais/metabolismo , Transporte Proteico
12.
J Cell Sci ; 134(13)2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34106255

RESUMO

Mitochondrial supercomplexes form around a conserved core of monomeric complex I and dimeric complex III; wherein a subunit of the former, NDUFA11, is conspicuously situated at the interface. We identified nduf-11 (B0491.5) as encoding the Caenorhabditis elegans homologue of NDUFA11. Animals homozygous for a CRISPR-Cas9-generated knockout allele of nduf-11 arrested at the second larval (L2) development stage. Reducing (but not eliminating) expression using RNAi allowed development to adulthood, enabling characterisation of the consequences: destabilisation of complex I and its supercomplexes and perturbation of respiratory function. The loss of NADH dehydrogenase activity was compensated by enhanced complex II activity, with the potential for detrimental reactive oxygen species (ROS) production. Cryo-electron tomography highlighted aberrant morphology of cristae and widening of both cristae junctions and the intermembrane space. The requirement of NDUF-11 for balanced respiration, mitochondrial morphology and development presumably arises due to its involvement in complex I and supercomplex maintenance. This highlights the importance of respiratory complex integrity for health and the potential for its perturbation to cause mitochondrial disease. This article has an associated First Person interview with Amber Knapp-Wilson, joint first author of the paper.


Assuntos
Complexo I de Transporte de Elétrons , Mitocôndrias , Animais , Caenorhabditis elegans , Transporte de Elétrons , Complexo I de Transporte de Elétrons/genética , Complexo I de Transporte de Elétrons/metabolismo , Humanos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Oxirredução , Espécies Reativas de Oxigênio/metabolismo
13.
Commun Biol ; 4(1): 667, 2021 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-34083717

RESUMO

Complex formation between hexokinase-II (HKII) and the mitochondrial VDAC1 is crucial to cell growth and survival. We hypothesize that HKII first inserts into the outer membrane of mitochondria (OMM) and then interacts with VDAC1 on the cytosolic leaflet of OMM to form a binary complex. To systematically investigate this process, we devised a hybrid approach. First, we describe membrane binding of HKII with molecular dynamics (MD) simulations employing a membrane mimetic model with enhanced lipid diffusion capturing membrane insertion of its H-anchor. The insertion depth of the H-anchor was then used to derive positional restraints in subsequent millisecond-scale Brownian dynamics (BD) simulations to preserve the membrane-bound pose of HKII during the formation of the HKII/VDAC1 binary complex. Multiple BD-derived structural models for the complex were further refined and their structural stability probed with additional MD simulations, resulting in one stable complex. A major feature in the complex is the partial (not complete) blockade of VDAC1's permeation pathway, a result supported by our comparative electrophysiological measurements of the channel in the presence and absence of HKII. We also show how VDAC1 phosphorylation disrupts HKII binding, a feature that is verified by our electrophysiology recordings and has implications in mitochondria-mediated cell death.


Assuntos
Hexoquinase/metabolismo , Proteínas Mitocondriais/metabolismo , Simulação de Dinâmica Molecular , Complexos Multiproteicos/metabolismo , Canal de Ânion 1 Dependente de Voltagem/metabolismo , Sítios de Ligação , Cristalografia por Raios X , Hexoquinase/química , Hexoquinase/genética , Humanos , Membranas Mitocondriais/metabolismo , Proteínas Mitocondriais/química , Proteínas Mitocondriais/genética , Complexos Multiproteicos/química , Complexos Multiproteicos/genética , Mutação , Ligação Proteica , Domínios Proteicos , Canal de Ânion 1 Dependente de Voltagem/química , Canal de Ânion 1 Dependente de Voltagem/genética
14.
Toxicology ; 458: 152836, 2021 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-34147545

RESUMO

China's clean energy and resources are mainly located in the west and north while electric load center is concentrated in the middle and east. Thus, these resources and energy need to be converted into electrical energy in situ and transported to electric load center through ultra-high voltage direct current (UHVDC) transmissions. China has built 25,000 km UHVDC transmission lines of 800 kV and 1100 kV, near which the impact of electric field on health has attracted public attention. Previous studies showed that time-varying electromagnetic field exposure could disturb testosterone secretion. To study the effect of non-time-varying electric field caused by direct current transmission lines on testosterone synthesis, male ICR mice were continually (24 h/d) exposed to static electric field of 56.3 ± 1.4 kV/m. Results showed that on the 3rd day of exposure and on the 7th day after ceasing the exposure of 28 d, serum testosterone level and testicular oxidative stress indicators didn't change significantly. On the 28th day of exposure, serum testosterone levels, testicular glutathione peroxidase (GSH-Px) activity, the mRNA and protein levels of testicular StAR, PBR, CYP11A1 decreased significantly, and testicular malondialdehyde (MDA) content increased significantly. Meanwhile, electron-dense edges and vacuolation appeared in lipid droplets of Leydig cells. The gap between inner mitochondrial membrane (IMM) and outer mitochondrial membrane (OMM) enlarged, which would cause the swelling of mitochondria, the rupture and deficiency of mitochondrial membranes. Analysis showed that testicular oxidative stress could induce the damage of mitochondrial structure in Leydig cells, which would decrease the rate of cholesterol transport from cytoplasm to mitochondria. Since cholesterol is the necessary precursor of testosterone synthesis, testosterone synthesis was inhibited. The decrease of the mRNA and protein expression levels of StAR and PBR in testes could diminish the cholesterol transported from OMM to IMM. The decrease of the mRNA and protein expression levels of CYP11A1 could reduce the pregnenolone required in testosterone synthesis and inhibit testosterone synthesis consequently.


Assuntos
Campos Eletromagnéticos , Células Intersticiais do Testículo/metabolismo , Células Intersticiais do Testículo/efeitos da radiação , Testosterona/biossíntese , Animais , Antioxidantes/metabolismo , Colesterol/metabolismo , Citoplasma/metabolismo , Citoplasma/efeitos da radiação , Glutationa Peroxidase/metabolismo , Células Intersticiais do Testículo/ultraestrutura , Masculino , Camundongos , Camundongos Endogâmicos ICR , Membranas Mitocondriais/metabolismo , Membranas Mitocondriais/efeitos da radiação , Dilatação Mitocondrial/efeitos da radiação , Estresse Oxidativo/efeitos da radiação , Fosfoproteínas/metabolismo , Testosterona/sangue , Vacúolos/efeitos da radiação , Vacúolos/ultraestrutura
15.
Methods Mol Biol ; 2276: 103-112, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34060035

RESUMO

Native electrophoresis is a powerful tool to analyze the mitochondrial electron transport chain complexes (Cx) I-V and their assembly into supercomplexes. Valuable information regarding the composition and bioenergetic regulation in physiological and pathological conditions can be obtained. This chapter compares different types of native electrophoresis to analyze mitochondrial supercomplexes.


Assuntos
Complexo de Proteínas da Cadeia de Transporte de Elétrons/metabolismo , Eletroforese em Gel Bidimensional/métodos , Eletroforese em Gel de Poliacrilamida/métodos , Immunoblotting/métodos , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Proteínas Mitocondriais/metabolismo , Animais , Transporte de Elétrons , Complexo de Proteínas da Cadeia de Transporte de Elétrons/química , Humanos , Proteínas Mitocondriais/química
16.
Methods Mol Biol ; 2276: 129-141, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34060037

RESUMO

Cellular energy metabolism is regulated by complex metabolic pathways. Although anaerobic glycolysis was reported as a primary source of energy in cancer leading to a high rate of lactate production, current evidence shows that the main energy source supporting cancer cell metabolism relies on mitochondrial metabolism. Mitochondria are the key organelle maintaining optimal cellular energy levels. MitoPlate™ S-1 provides a highly reproducible bioenergetics tool to analyze the electron flow rate in live cells. Measuring the rates of electron flow into and through the electron transport chain using different NADH and FADH2-producing metabolic substrates enables the assessment of mitochondrial functionality. MitoPlate™ S-1 are 96-well microplates pre-coated with different substrates used as probes to examine the activity of mitochondrial metabolic pathways based on a colorimetric assay. A comparative metabolic analysis between cell lines or primary cells allows to establish a specific metabolic profile and to detect possible alterations of the mitochondrial function of a tumor cell. Moreover, the direct measurements of electron flux triggered by metabolic pathway activation could highlight targets for potential drug candidates.


Assuntos
Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Neoplasias/metabolismo , Linhagem Celular Tumoral , Transporte de Elétrons , Ensaios de Triagem em Larga Escala/métodos , Humanos , Redes e Vias Metabólicas , Neoplasias/patologia , Oxirredução
17.
Methods Mol Biol ; 2276: 235-248, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34060046

RESUMO

Mitochondria are intracellular organelles, which play a crucial role in the generation of ATP. Mitochondria are surrounded by a double membrane, consisting of a smooth outer membrane (OMM) and a markedly folded inner mitochondrial membrane (IMM). Mitochondrion that has been stripped of its outer membrane, leaving the inner membrane intact is called mitoplast. There is a number of different transport proteins located in the inner mitochondrial membrane including ion channels that mediate fluxes of potassium, calcium, and chloride ions. These channels regulate the mitochondrial membrane potential, respiration, and production of reactive oxygen species. The stability of mitoplasts offers the possibility of measuring the activity of ion channels from IMM using the patch-clamp technique. Electrophysiological measurements of currents through ion channels in the IMM permit discovery of unique properties of these channels with the aim of new specific pharmacological therapies. In this chapter, we describe the isolation of mitochondria, preparation of mitoplast for patch-clamp recordings and single-mitoplast PCR experiments, which can be helpful in mastering the technique of recording the activity of mitochondrial ion channels.


Assuntos
Canais Iônicos/metabolismo , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Técnicas de Patch-Clamp/métodos , Animais , Células Cultivadas , Humanos , Potencial da Membrana Mitocondrial
18.
Molecules ; 26(11)2021 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-34072205

RESUMO

Mitochondria play a key role in energy metabolism within the cell. Potassium channels such as ATP-sensitive, voltage-gated or large-conductance Ca2+-regulated channels have been described in the inner mitochondrial membrane. Several hypotheses have been proposed to describe the important roles of mitochondrial potassium channels in cell survival and death pathways. In the current study, we identified two populations of mitochondrial large-conductance Ca2+-regulated potassium (mitoBKCa) channels in human bronchial epithelial (HBE) cells. The biophysical properties of the channels were characterized using the patch-clamp technique. We observed the activity of the channel with a mean conductance close to 285 pS in symmetric 150/150 mM KCl solution. Channel activity was increased upon application of the potassium channel opener NS11021 in the micromolar concentration range. The channel activity was completely inhibited by 1 µM paxilline and 300 nM iberiotoxin, selective inhibitors of the BKCa channels. Based on calcium and iberiotoxin modulation, we suggest that the C-terminus of the protein is localized to the mitochondrial matrix. Additionally, using RT-PCR, we confirmed the presence of α pore-forming (Slo1) and auxiliary ß3-ß4 subunits of BKCa channel in HBE cells. Western blot analysis of cellular fractions confirmed the mitochondrial localization of α pore-forming and predominately ß3 subunits. Additionally, the regulation of oxygen consumption and membrane potential of human bronchial epithelial mitochondria in the presence of the potassium channel opener NS11021 and inhibitor paxilline were also studied. In summary, for the first time, the electrophysiological and functional properties of the mitoBKCa channel in a bronchial epithelial cell line were described.


Assuntos
Brônquios/metabolismo , Cálcio/metabolismo , Células Epiteliais/metabolismo , Canais de Potássio Ativados por Cálcio de Condutância Alta/metabolismo , Consumo de Oxigênio , Potássio/metabolismo , Biofísica , Sobrevivência Celular , Eletrofisiologia , Metabolismo Energético , Epitélio/metabolismo , Humanos , Indóis/química , Potencial da Membrana Mitocondrial , Potenciais da Membrana , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Técnicas de Patch-Clamp , Peptídeos/química , Domínios Proteicos
19.
FASEB J ; 35(7): e21688, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34143516

RESUMO

The mitochondria-associated membrane (MAM) is a functional subdomain of the endoplasmic reticulum membrane that tethers to the mitochondrial outer membrane and is essential for cellular homeostasis. A defect in MAM is involved in various neurological diseases, including amyotrophic lateral sclerosis (ALS). Recently, we and others reported that MAM was disrupted in the models expressing several ALS-linked genes, including SOD1, SIGMAR1, VAPB, TARDBP, and FUS, suggesting that MAM disruption is deeply involved in the pathomechanism of ALS. However, it is still uncertain whether MAM disruption is a common pathology in ALS, mainly due to the absence of a simple, quantitative tool for monitoring the status of MAM. In this study, to examine the effects of various ALS-causative genes on MAM, we created the following two novel MAM reporters: MAMtracker-Luc and MAMtracker-Green. The MAMtrackers could detect MAM disruption caused by suppression of SIGMAR1 or the overexpression of ALS-linked mutant SOD1 in living cells. Moreover, the MAMtrackers have an advantage in their ability to monitor reversible changes in the MAM status induced by nutritional conditions. We used the MAMtrackers with an expression plasmid library of ALS-causative genes and noted that 76% (16/21) of the genes altered MAM integrity. Our results suggest that MAM disruption is a common pathological feature in ALS. Furthermore, we anticipate our MAMtrackers, which are suitable for high-throughput assays, to be valuable tools to understand MAM dynamics.


Assuntos
Esclerose Amiotrófica Lateral/patologia , Mitocôndrias/patologia , Membranas Mitocondriais/patologia , Proteínas Mitocondriais/metabolismo , Mutação , Neuroblastoma/patologia , Esclerose Amiotrófica Lateral/etiologia , Esclerose Amiotrófica Lateral/metabolismo , Animais , Humanos , Camundongos , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Proteínas Mitocondriais/genética , Neuroblastoma/genética , Neuroblastoma/metabolismo
20.
Int J Mol Sci ; 22(9)2021 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-34063207

RESUMO

Recent studies have implicated mitochondrial disruption in podocyte dysfunction, which is a characteristic feature of primary and diabetic glomerular diseases. However, the mechanisms by which primary mitochondrial dysfunction in podocytes affects glomerular renal diseases are currently unknown. To investigate the role of mitochondrial oxidative phosphorylation (OxPhos) in podocyte dysfunction, glomerular function was examined in mice carrying a loss of function mutation of the gene encoding CR6-interacting factor-1 (CRIF1), which is essential for intramitochondrial production and the subsequent insertion of OxPhos polypeptides into the inner mitochondrial membrane. Homozygotic deficiency of CRIF1 in podocytes resulted in profound and progressive albuminuria from 3 weeks of age; the CRIF1-deficient mice also developed glomerular and tubulointerstitial lesions by 10 weeks of age. Furthermore, marked glomerular sclerosis and interstitial fibrosis were observed in homozygous CRIF1-deficient mice at 20 weeks of age. In cultured mouse podocytes, loss of CRIF1 resulted in OxPhos dysfunction and marked loss or abnormal aggregation of F-actin. These findings indicate that the OxPhos status determines the integrity of podocytes and their ability to maintain a tight barrier and control albuminuria. Analyses of the glomerular function of the podocyte-specific primary OxPhos dysfunction model mice demonstrate a link between podocyte mitochondrial dysfunction, progressive glomerular sclerosis, and tubulointerstitial diseases.


Assuntos
Albuminúria/metabolismo , Proteínas de Ciclo Celular/deficiência , Proteínas de Ciclo Celular/metabolismo , Mitocôndrias/metabolismo , Podócitos/metabolismo , Esclerose/metabolismo , Albuminúria/genética , Albuminúria/patologia , Animais , Proteínas de Ciclo Celular/genética , Nefropatias Diabéticas/metabolismo , Modelos Animais de Doenças , Feminino , Fibrose , Rim/patologia , Masculino , Camundongos , Camundongos Knockout , Mitocôndrias/genética , Membranas Mitocondriais/metabolismo , Fosforilação Oxidativa , Peptídeos/metabolismo , Esclerose/genética , Esclerose/patologia
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