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1.
Biology (Basel) ; 13(9)2024 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-39336173

RESUMO

Mitochondria are dynamic organelles that can adjust and respond to different stimuli within a cell. This plastic ability allows them to effectively coordinate several cellular functions in cells and becomes particularly relevant in highly complex cells such as neurons. An imbalance in mitochondrial dynamics can disrupt mitochondrial function, leading to abnormal cellular function and ultimately to a range of diseases, including neurodegenerative disorders. Regulation of mRNA transport and local translation inside neurons is crucial for maintaining the proteome of distal mitochondria, which is vital for energy production and synaptic function. A significant portion of the axonal transcriptome is dedicated to mRNAs for mitochondrial proteins, emphasizing the importance of local translation in sustaining mitochondrial function in areas far from the cell body. In neurons, local translation and the regulation of mRNAs encoding mitochondrial-shaping proteins could be essential for synaptic plasticity and neuronal health. The dynamics of these mRNAs, including their transport and local translation, may influence the morphology and function of mitochondria, thereby affecting the overall energy status and responsiveness of synapses. Comprehending the mitochondria-related mRNA regulation and local translation, as well as its influence on mitochondrial morphology near the synapses will help to better understand neuronal physiology and neurological diseases where mitochondrial dysfunction and impaired synaptic plasticity play a central role.

2.
Cell Mol Life Sci ; 80(6): 173, 2023 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-37266732

RESUMO

Mitochondria are present in the pre- and post-synaptic regions, providing the energy required for the activity of these very specialized neuronal compartments. Biogenesis of synaptic mitochondria takes place in the cell body, and these organelles are then transported to the synapse by motor proteins that carry their cargo along microtubule tracks. The transport of mitochondria along neurites is a highly regulated process, being modulated by the pattern of neuronal activity and by extracellular cues that interact with surface receptors. These signals act by controlling the distribution of mitochondria and by regulating their activity. Therefore, mitochondria activity at the synapse allows the integration of different signals and the organelles are important players in the response to synaptic stimulation. Herein we review the available evidence regarding the regulation of mitochondrial dynamics by neuronal activity and by neuromodulators, and how these changes in the activity of mitochondria affect synaptic communication.


Assuntos
Mitocôndrias , Neurônios , Mitocôndrias/metabolismo , Neurônios/metabolismo , Organelas/metabolismo , Cinesinas/metabolismo , Microtúbulos/metabolismo
3.
Membranes (Basel) ; 12(10)2022 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-36295740

RESUMO

Uropathogenic Escherichia coli (UPEC) are one of the most common agents of urinary tract infection. In the last decade, several UPEC strains have acquired antibiotic resistance mechanisms and some have become resistant to all classes of antibiotics. UPEC outer membrane proteins (OMPs) seem to have a decisive role not only in the processes of invasion and colonization of the bladder mucosa, but also in mechanisms of drug resistance, by which bacteria avoid killing by antimicrobial molecules. This systematic review was performed according to the PRISMA guidelines, aiming to characterize UPEC OMPs and identify their potential role in antimicrobial resistance. The search was limited to studies in English published during the last decade. Twenty-nine studies were included for revision and, among the 76 proteins identified, seven were associated with antibiotic resistance. Indeed, OmpC was associated with ß-lactams resistance and OmpF with ß-lactams and fluoroquinolone resistance. In turn, TolC, OmpX, YddB, TosA and murein lipoprotein (Lpp) were associated with fluoroquinolones, enrofloxacin, novobiocin, ß-lactams and globomycin resistances, respectively. The clinical implications of UPEC resistance to antimicrobial agents in both veterinary and human medicine must propel the implementation of new strategies of administration of antimicrobial agents, while also promoting the development of improved antimicrobials, protective vaccines and specific inhibitors of virulence and resistance factors.

4.
Membranes (Basel) ; 11(9)2021 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-34564463

RESUMO

The development and adoption of cell therapies has been largely limited by difficulties associated with their safety, handling, and storage. Extracellular vesicles (EV) have recently emerged as a likely mediator for the therapeutic effect of cells, offering several advantages over cell therapies. Due to their small size and inability to expand and metastasize, EV are generally considered safer than cell transplantation. Nevertheless, few studies have scrutinized the toxicity profile of EV, particularly after repeated high-dose administration. The present study aimed to evaluate a preparation of small EV obtained from umbilical cord blood mononuclear cells (UCB-MNC-sEV) for its cytotoxicity in different cell lines, as well as its differential accumulation, distribution, and toxicity following repeated intravenous (IV) administrations in a rodent model. In vitro, repeated sEV exposure in concentrations up to 1 × 1011 particles/mL had no deleterious impact on the viability or metabolic activity of peripheral blood mononuclear cells, THP-1 monocytes, THP-1-derived macrophages, normal dermal human fibroblasts, or human umbilical vein endothelial cells. DiR-labelled sEV, injected intravenously for four weeks in healthy rats, were detected in clearance organs, particularly the kidneys, spleen, and liver, similarly to control dye. Moreover, repeated administrations for six and twelve weeks of up to 1 × 1010 total particles of sEV dye were well-tolerated, with no changes in general haematological cell counts, or kidney and liver toxicity markers. More importantly, unlabelled sEV likewise did not induce significant alterations in cellular and biochemical blood parameters, nor any morphological changes in the heart, kidney, lung, spleen, or liver tissue. In sum, our data show that UCB-MNC-sEV have no significant toxicity in vitro or in vivo, even when administered repeatedly at high concentrations, therefore confirming their safety profile and potential suitability for future clinical use.

5.
Int J Mol Sci ; 22(18)2021 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-34575956

RESUMO

Umbilical cord blood (UCB) has long been seen as a rich source of naïve cells with strong regenerative potential, likely mediated by paracrine signals. More recently, small extracellular vesicles (sEV), such as exosomes, have been shown to play essential roles in cell-to-cell communication, via the transport of numerous molecules, including small RNAs. Often explored for their potential as biomarkers, sEV are now known to have regenerative and immunomodulating characteristics, particularly if isolated from stem cell-rich tissues. In this study, we aim to characterize the immunomodulating properties of umbilical cord blood mononuclear cell-derived sEV (UCB-MNC-sEV) and explore their therapeutic potential for inflammatory skin diseases. UCB-MNC-sEV were shown to shift macrophages toward an anti-inflammatory phenotype, which in turn exert paracrine effects on fibroblasts, despite previous inflammatory stimuli. Additionally, the incubation of PBMC with UCB-MNC-sEV resulted in a reduction of total CD4+ and CD8+ T-cell proliferation and cytokine release, while specifically supporting the development of regulatory T-cells (Treg), by influencing FOXP3 expression. In a 3D model of psoriatic skin, UCB-MNC-sEV reduced the expression of inflammatory and psoriatic markers IL6, IL8, CXCL10, COX2, S100A7, and DEFB4. In vivo, UCB-MNC-sEV significantly prevented or reversed acanthosis in imiquimod-induced psoriasis, and tendentially increased the number of Treg in skin, without having an overall impact on disease burden. This work provides evidence for the anti-inflammatory and tolerogenic effect of UCB-MNC-sEV, which may be harnessed for the treatment of Th17-driven inflammatory skin diseases, such as psoriasis.


Assuntos
Exossomos/imunologia , Fatores de Transcrição Forkhead/genética , Imunomodulação/imunologia , Inflamação/terapia , Psoríase/terapia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Comunicação Celular/genética , Comunicação Celular/imunologia , Proliferação de Células/genética , Citocinas/genética , Exossomos/genética , Exossomos/transplante , Vesículas Extracelulares/transplante , Feminino , Sangue Fetal/imunologia , Sangue Fetal/transplante , Humanos , Imunomodulação/genética , Inflamação/sangue , Inflamação/patologia , Macrófagos/imunologia , Masculino , Comunicação Parácrina/genética , Comunicação Parácrina/imunologia , Psoríase/sangue , Psoríase/patologia , Linfócitos T Reguladores/imunologia
6.
Sci Rep ; 11(1): 11374, 2021 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-34059735

RESUMO

Cell culture models are important tools to study epileptogenesis mechanisms. The aim of this work was to characterize the spontaneous and synchronized rhythmic activity developed by cultured hippocampal neurons after transient incubation in zero Mg2+ to model Status Epilepticus. Cultured hippocampal neurons were transiently incubated with a Mg2+-free solution and the activity of neuronal networks was evaluated using single cell calcium imaging and whole-cell current clamp recordings. Here we report the development of synchronized and spontaneous [Ca2+]i transients in cultured hippocampal neurons immediately after transient incubation in a Mg2+-free solution. Spontaneous and synchronous [Ca2+]i oscillations were observed when the cells were then incubated in the presence of Mg2+. Functional studies also showed that transient incubation in Mg2+-free medium induces neuronal rhythmic burst activity that was prevented by antagonists of glutamate receptors. In conclusion, we report the development of epileptiform-like activity, characterized by spontaneous and synchronized discharges, in cultured hippocampal neurons transiently incubated in the absence of Mg2+. This model will allow studying synaptic alterations contributing to the hyperexcitability that underlies the development of seizures and will be useful in pharmacological studies for testing new drugs for the treatment of epilepsy.


Assuntos
Epilepsia/fisiopatologia , Hipocampo/metabolismo , Magnésio/metabolismo , Neurônios/metabolismo , Animais , Cálcio/metabolismo , Células Cultivadas , Meios de Cultura , Hipocampo/citologia , Hipocampo/fisiopatologia , Técnicas de Patch-Clamp , Ratos , Ratos Wistar
7.
Stem Cells Transl Med ; 10(6): 910-921, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33577723

RESUMO

Extracellular vesicles (EV) are a promising therapeutic tool in regenerative medicine. These particles were shown to accelerate wound healing, through delivery of regenerative mediators, such as microRNAs. Herein we describe an optimized and upscalable process for the isolation of EV smaller than 200 nm (sEV), secreted by umbilical cord blood mononuclear cells (UCB-MNC) under ischemic conditions and propose quality control thresholds for the isolated vesicles, based on the thorough characterization of their protein, lipid and RNA content. Ultrafiltration and size exclusion chromatography (UF/SEC) optimized methodology proved superior to traditional ultracentrifugation (UC), regarding production time, standardization, scalability, and vesicle yield. Using UF/SEC, we were able to recover approximately 400 times more sEV per mL of media than with UC, and upscaling this process further increases EV yield by about 3-fold. UF/SEC-isolated sEV display many of the sEV/exosomes classical markers and are enriched in molecules with anti-inflammatory and regenerative capacity, such as hemopexin and miR-150. Accordingly, treatment with sEV promotes angiogenesis and extracellular matrix remodeling, in vitro. In vivo, UCB-MNC-sEV significantly accelerate skin regeneration in a mouse model of delayed wound healing. The proposed isolation protocol constitutes a significant improvement compared to UC, the gold-standard in the field. Isolated sEV maintain their regenerative properties, whereas downstream contaminants are minimized. The use of UF/SEC allows for the standardization and upscalability required for mass production of sEV to be used in a clinical setting.


Assuntos
Exossomos , Vesículas Extracelulares , Sangue Fetal , Animais , Biomarcadores , Camundongos , MicroRNAs
8.
Biology (Basel) ; 9(12)2020 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-33371511

RESUMO

The most famous role of mitochondria is to generate ATP through oxidative phosphorylation, a metabolic pathway that involves a chain of four protein complexes (the electron transport chain, ETC) that generates a proton-motive force that in turn drives the ATP synthesis by the Complex V (ATP synthase). An impressive number of more than 1000 mitochondrial proteins have been discovered. Since mitochondrial proteins have a dual genetic origin, it is predicted that ~99% of these proteins are nuclear-encoded and are synthesized in the cytoplasmatic compartment, being further imported through mitochondrial membrane transporters. The lasting 1% of mitochondrial proteins are encoded by the mitochondrial genome and synthesized by the mitochondrial ribosome (mitoribosome). As a result, an appropriate regulation of mitochondrial protein synthesis is absolutely required to achieve and maintain normal mitochondrial function. Regarding miRNAs in mitochondria, it is well-recognized nowadays that several cellular mechanisms involving mitochondria are regulated by many genetic players that originate from either nuclear- or mitochondrial-encoded small noncoding RNAs (sncRNAs). Growing evidence collected from whole genome and transcriptome sequencing highlight the role of distinct members of this class, from short interfering RNAs (siRNAs) to miRNAs and long noncoding RNAs (lncRNAs). Some of the mechanisms that have been shown to be modulated are the expression of mitochondrial proteins itself, as well as the more complex coordination of mitochondrial structure and dynamics with its function. We devote particular attention to the role of mitochondrial miRNAs and to their role in the modulation of several molecular processes that could ultimately contribute to tissue regeneration accomplishment.

9.
Br J Pharmacol ; 176(18): 3666-3680, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31220343

RESUMO

BACKGROUND AND PURPOSE: Parkinson's disease (PD) involves an initial loss of striatal dopamine terminals evolving into degeneration of dopamine neurons in substantia nigra (SN), which can be modelled by 6-hydroxydopamine (6-OHDA) administration. Adenosine A2A receptor blockade attenuates PD features in animal models, but the source of the adenosine causing A2A receptor over-activation is unknown. As ATP is a stress signal, we have tested if extracellular catabolism of adenine nucleotides into adenosine (through ecto-5'-nucleotidase or CD73) leads to A2A receptor over-activation in PD. EXPERIMENTAL APPROACH: Effects of blocking CD73 with α,ß-methylene ADP (AOPCP) were assayed in 6-OHDA-treated rats and dopamine-differentiated neuroblastoma SH-SY5Y cells. KEY RESULTS: 6-OHDA increased ATP release and extracellular conversion into adenosine through CD73 up-regulation in SH-SY5Y cells. Removing extracellular adenosine with adenosine deaminase, blocking CD73 with AOPCP, or blocking A2A receptors with SCH58261 were equi-effective in preventing 6-OHDA-induced damage in SH-SY5Y cells. In vivo striatal exposure to 6-OHDA increased ATP release and extracellular formation of adenosine from adenosine nucleotides and up-regulated CD73 and A2A receptors in striatal synaptosomes. Intracerebroventricular administration of AOPCP phenocopied effects of SCH58261, attenuating 6-OHDA-induced (a) increase of contralateral rotations after apomorphine, (b) reduction of dopamine content in striatum and SN, (c) loss of TH staining in striatum and SN, (d) motor dysfunction in the cylinder test, and (e) short-term memory impairment in the object recognition test. CONCLUSION AND IMPLICATIONS: Our data indicate that increased ATP-derived adenosine formation is responsible for A2A receptor over-activation in PD, suggesting CD73 as a new target to manage PD.


Assuntos
5'-Nucleotidase/metabolismo , Trifosfato de Adenosina/metabolismo , Adenosina/metabolismo , Transtornos Parkinsonianos/metabolismo , Receptor A2A de Adenosina/metabolismo , 5'-Nucleotidase/antagonistas & inibidores , Antagonistas do Receptor A2 de Adenosina/farmacologia , Difosfato de Adenosina/análogos & derivados , Difosfato de Adenosina/farmacologia , Animais , Linhagem Celular Tumoral , Humanos , Masculino , Oxidopamina/farmacologia , Pirimidinas/farmacologia , Ratos Wistar , Triazóis/farmacologia
10.
J Toxicol Environ Health A ; 80(19-21): 1129-1144, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28880749

RESUMO

Polybrominated diphenyl ethers (PBDE) are ubiquitous environmental pollutants. Exposure to these chemicals has been associated with developmental neurotoxicity, endocrine dysfunctions, reproductive disorders, and hepatotoxicity. The widespread use of PBDE as flame retardants has culminated in daily exposure of humans and wildlife to these contaminants and resulted in their banned use. Thus assessment of the potential effects of each PBDE congener on living organisms has become cause for concern. The aim of this study was to (1) examine the effects of decabromodiphenyl ether (BDE)-209 on different functions of HepG2 cells and (2) investigate whether this congener is involved in mitochondrial toxicity. The use of multiple methods was employed to (i) study the influence of BDE-209 on mitochondrial permeability transition (MPT) process in mitochondria isolated from rat liver and (ii) determine the consequential cellular damage. Our results showed that BDE-209 induced matrix swelling related to MPT with 10 µM and ATP depletion with 0.1 µM. In addition, 0.5 µM BDE-209 reduced HepG2 cell viability, produced collapse of membrane potential, but increased levels of reactive oxygen species (ROS) after 48 h incubation. After 24 h with 5 µM treatment elevated levels of ROS, DNA fragmentation and cytochrome c release, accompanied by caspase 9 and caspase 3 activation was noted. Taken together, these results suggest that short-duration exposure (24 or 48 h) to 0.5 µM or 5 µM BDE-209 concentrations diminished HepG2 cell viability due to apoptosis associated with mitochondrial dysfunction.


Assuntos
Poluentes Ambientais/toxicidade , Retardadores de Chama/toxicidade , Éteres Difenil Halogenados/toxicidade , Fígado/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Animais , Morte Celular/efeitos dos fármacos , Células Hep G2 , Humanos , Masculino , Mitocôndrias/fisiologia , Ratos , Ratos Wistar
11.
Purinergic Signal ; 13(2): 179-190, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-27848069

RESUMO

Although adenosine A1 receptors (A1R) have been associated to ischemic preconditioning (IPC), direct evidence for their ability to preserve mitochondrial function upon hepatic preconditioning is still missing and could represent a novel strategy to boost the quality of liver transplants. We tested if the A1R antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) prevented IPC in the liver and if the A1R agonist 2-chloro-N6-cyclopentyladenosine (CCPA) might afford a pharmacological preconditioning. Livers underwent a 120 min of 70% warm ischemia and 16 h of reperfusion (I/R), and the IPC group underwent a 5-min ischemic episode followed by a 10-min period of reperfusion before I/R. DPCPX or CCPA was administered intraperitoneally 2 h before IPC or I/R. The control of mitochondrial function emerged as the central element affected by IPC and controlled by endogenous A1R activation. Thus, livers from IPC- or CCPA-treated rats displayed an improved oxidative phosphorylation with higher state 3 respiratory rate, higher respiratory control ratio, increased ATP content, and decreased lag phase. IPC and CCPA also prevented the I/R-induced susceptibility to calcium-induced mitochondrial permeability transition, the rate of reactive oxygen species (ROS) generation, and the decreased mitochondrial content of phospho-Ser9 GSK-3ß. DPCPX abrogated these effects of IPC. These implicate the control of GSK-3ß activity by Akt-mediated Ser9-GSK-3ß phosphorylation preserving the efficiency of oxidative phosphorylation and ROS-mediated cell death in the ability of A1R activation to mimic IPC in the liver. In conclusion, the parallel between IPC and A1R-mediated preconditioning also paves the way to consider a putative therapeutic use of the later in liver transplants.


Assuntos
Precondicionamento Isquêmico/métodos , Fígado/metabolismo , Mitocôndrias/metabolismo , Receptor A1 de Adenosina/metabolismo , Agonistas do Receptor A1 de Adenosina/farmacologia , Antagonistas do Receptor A1 de Adenosina/farmacologia , Animais , Fígado/irrigação sanguínea , Fígado/efeitos dos fármacos , Masculino , Mitocôndrias/efeitos dos fármacos , Ratos , Ratos Wistar
12.
Basic Clin Pharmacol Toxicol ; 119(5): 485-497, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27060917

RESUMO

Apoptotic cell death is one of the main consequences of exposure to brominated flame retardants, including polybrominated diphenyl ethers. However, few of these compounds have had their potential toxicity investigated. BDE-154 is one of the most poorly studied polybrominated diphenyl ether (PBDE) congeners, but its level in the environment and in biological fluids is rising. In addition, its chemical structure differs from the other congeners with well-documented toxicity, so BDE-154 may display a distinct toxicity pattern. This study has evaluated how BDE-154 affects the human hepatoblastoma cell line (HepG2) and has looked into the impact of this congener on human health. In addition, this study has related the effects of BDE-154 with the effects of BDE-47 to clarify the mechanism of PBDE toxicity. The HepG2 cell line was exposed to BDEs for 24 and 48 hr and submitted to assays to examine proliferation, viability, mitochondrial membrane potential, reactive oxygen species accumulation, phosphatidylserine exposure, nuclear fragmentation and evaluation of pro-caspase 3, pro-caspase 9, cytochrome c release, and apoptosis inductor factor release by Western blot analysis. BDE-154 induced mitochondrial damage and led to apoptotic death of HepG2 cells, but these effects were less intense than the effects promoted by BDE-47. Unlike other extensively reported congeners, BDE-154 was only toxic at the higher tested concentrations, whereas BDE-47 cytotoxicity was evident even at lower concentrations. Hence, like the toxicity pattern of other classes of substances such as polychlorinated biphenyls, the toxicity pattern of BDEs also depends on their chemical structure and aromatic substituent.


Assuntos
Apoptose/efeitos dos fármacos , Retardadores de Chama/toxicidade , Éteres Difenil Halogenados/toxicidade , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Bifenil Polibromatos/toxicidade , Fator de Indução de Apoptose/metabolismo , Caspase 3/metabolismo , Caspase 9/metabolismo , Citocromos c/metabolismo , Células Hep G2 , Humanos , Espécies Reativas de Oxigênio/metabolismo
13.
Adv Exp Med Biol ; 888: 123-54, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26663182

RESUMO

microRNAs (miRNAs) are small, single-stranded noncoding RNA molecules involved in posttranscriptional control of gene expression of a wide number of genes. miRNAs align and bind especially to 3'UTR sequences of their target genes and initiate either mRNA degradation or translational repression, resulting in reduced protein levels. miRNAs are now recognized as major players in virtually every biological process. In recent years, the discovery of miRNAs has revolutionized the traditional view of gene expression and our understanding of miRNA biogenesis and function has thereby expanded. The discovery of mitochondrial-located miRNAs raises the issue of the molecular mechanism underlying their translocation from the nucleus to the mitochondria. Studies in different species indicate that it may exist a number of import pathways of nucleus-encoded RNAs to mitochondria, being the most of them largely ATP-dependent. Not only pre-miRNAs, but also mature miRNAs, are present in the mitochondria; these findings have also raised the possibility of mitochondrial miRNA synthesis. Some pre-miRNAs sequences seem to be processed in the mitochondria, giving origin to mature miRNAs, which could be immediately active on the mitochondrial transcripts or exported to the cytosol in order to interfere with genomic-derived mRNA. Thus, the mitochondrial-processed miRNAs are likely to contribute to some posttranscriptional regulation of gene expression related to the mitochondrial functions. Coming from their location, the mitochondria, some miRNAs are currently named as mitomiRs; it refers to those miRNAs that can localize in mitochondria, whether transcribed from the nuclear or, potentially, the mitochondrial genome. When their genomics was analyzed, a number of mitomiRs mapped the nuclear genome at loci relevant to mitochondrial functions or diseases. Current computational analyses, using different algorithms, drive scientists to argue that the mitochondrial genome can harbor sequences that could be a target for several mitomiRs. However, perhaps a more challenging topic concerning mitomiRs is whether the mitochondrial DNA can harbor miRNA sequences, indicating an involvement of mitochondria in small RNA-generating pathways. The identification of populations of miRNAs in the mitochondria pushed scientists in the field to question its biological functions. It is established that miRNAs, originated in the nuclear genome, are exported to cytosol where they are processed and exert their function by inhibiting nuclear genome-derived mRNA. Actually it is also known that some miRNAs are imported into mitochondria where they interact with some mitochondrial genome-derived mRNA molecules. More strikingly, it has also come to light that mitochondrial genome (mtDNA) can originate some miRNA molecules that exert their function directly on mitochondrial transcripts. The links between miRNA deregulation and human disease have been reported in almost all medicine fields. Currently, great efforts are being invested in understanding the involvement of miRNA deregulation in disease and unlocking the mechanisms by which they act. This new field of investigation has revealed the tremendous potential of miRNAs as diagnostic or even as valuable therapeutic tools. miRNAs have recently emerged as key regulators of metabolism. Metabolic syndrome is a systemic disorder that includes a spectrum of abnormalities associated with obesity and type II diabetes. Defects in mitochondrial function, namely related to oxidation of fatty acids, have been linked to diet-induced obesity and the development of insulin resistance in adipose tissue and skeletal muscle. Consistently, obese individuals have mitochondria with compromised bioenergetic capacity. Therefore, increasing interest is being given to the role of miRNAs on metabolic regulation, with relevance on mitochondria and the mechanisms purported for miRNA actions, particularly acting in mitochondria or in mitochondria-related pathways. The involvement of miRNAs in mitochondrial metabolism, mitochondrial oxidative phosphorylation (OXPHOS), electron transport chain (ETC) components, lipid metabolism, and metabolic disorders is becoming more and more comprehended, as well as miRNAs contribution for processes such as mitochondrial dynamics or apoptosis regulation and cancer.


Assuntos
Doenças Metabólicas/genética , MicroRNAs/genética , Mitocôndrias/genética , Neoplasias/genética , Doenças Neurodegenerativas/genética , Regulação da Expressão Gênica , Genoma Mitocondrial/genética , Humanos , Mitocôndrias/metabolismo , Dinâmica Mitocondrial/genética , Modelos Genéticos , Fosforilação Oxidativa , RNA/genética , RNA/metabolismo , RNA Mitocondrial
14.
Curr Med Chem ; 22(20): 2468-79, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25973983

RESUMO

Mitochondria are key players in the maintenance of cellular homeostasis, as they generate ATP via OXPHOS. As such, disruption in mitochondrial homeostasis is closely associated with disease states, caused by subtle alterations in the function of tissues or by major defects, particularly evident in tissues with high metabolic demands. Adaptations in mitochondrial copy number or mitochondrial mass, and the induction of genes implicated in OXPHOS or in intermediary metabolism as well, depend on the balanced contribution of both the nuclear and mitochondrial genomes. This forms a biogenesis program, controlled by several nuclear factors that act coordinately and in a categorized manner. Dynamic changes in mitochondrial regulators are associated with post-translational modifications mediated by metabolic sensors, such as SIRT1 and AMPK. Nrf2, which induces an antioxidant protective response against oxidative stress, also modulates bioenergetic function and metabolism. Additionally, the stability of mitochondrial transcripts is decreased by miRNA detected in the mitochondria, thus affecting the bioenergetic capacity of the cell. However, mitochondrial adaptation to metabolic demands is also dependent on the removal of damaged mitochondria (mitophagy) and fission/fusion events of the mitochondrial network.


Assuntos
Mitocôndrias/metabolismo , Estresse Oxidativo , Animais , Humanos
15.
Genes (Basel) ; 5(4): 865-86, 2014 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-25264560

RESUMO

MicroRNAs (miRNAs) are short, single-stranded, non-coding RNA molecules that act as post-transcriptional gene regulators. They can inhibit target protein-coding genes, through repressing messenger RNA (mRNA) translation or promoting their degradation. miRNAs were initially found to be originated from nuclear genome and exported to cytosol; where they exerted most of their actions. More recently, miRNAs were found to be present specifically in mitochondria; even originated there from mitochondrial DNA, regulating in a direct manner genes coding for mitochondrial proteins, and consequently mitochondrial function. Since miRNAs are recognized as major players in several biological processes, they are being considered as a key to better understand, explain, and probably prevent/cure not only the pathogenesis of multifactorial diseases but also mitochondrial dysfunction and associated diseases. Here we review some of the molecular mechanisms purported for miRNA actions in several biological processes, particularly the miRNAs acting in mitochondria or in mitochondria-related mechanisms.

16.
Cell Metab ; 15(5): 675-90, 2012 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-22560220

RESUMO

Resveratrol induces mitochondrial biogenesis and protects against metabolic decline, but whether SIRT1 mediates these benefits is the subject of debate. To circumvent the developmental defects of germline SIRT1 knockouts, we have developed an inducible system that permits whole-body deletion of SIRT1 in adult mice. Mice treated with a moderate dose of resveratrol showed increased mitochondrial biogenesis and function, AMPK activation, and increased NAD(+) levels in skeletal muscle, whereas SIRT1 knockouts displayed none of these benefits. A mouse overexpressing SIRT1 mimicked these effects. A high dose of resveratrol activated AMPK in a SIRT1-independent manner, demonstrating that resveratrol dosage is a critical factor. Importantly, at both doses of resveratrol no improvements in mitochondrial function were observed in animals lacking SIRT1. Together these data indicate that SIRT1 plays an essential role in the ability of moderate doses of resveratrol to stimulate AMPK and improve mitochondrial function both in vitro and in vivo.


Assuntos
Mitocôndrias/efeitos dos fármacos , Músculo Esquelético/efeitos dos fármacos , Proteínas Quinases/metabolismo , Sirtuína 1/metabolismo , Estilbenos/farmacologia , Quinases Proteína-Quinases Ativadas por AMP , Animais , Células Cultivadas , Ativação Enzimática , Hepatócitos/efeitos dos fármacos , Hepatócitos/enzimologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias/enzimologia , Mitocôndrias/genética , Músculo Esquelético/enzimologia , NAD/metabolismo , Proteínas Quinases/genética , Resveratrol , Transdução de Sinais/efeitos dos fármacos , Sirtuína 1/genética
17.
Toxicol Lett ; 209(1): 35-42, 2012 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-22173198

RESUMO

Environmental pollutants, such as dioxins and furans, are extremely toxic and related with pulmonary disease development. Exposure of A549 human lung cells to dibenzofuran showed both time- and concentration-dependent decreases in cell proliferation and MTT reduction, but no alterations in cell viability. No differences were observed in the number of apoptotic nuclei, which can be due to the energetic failure caused by dibenzofuran-induced ATP depletion. Moreover, cells in culture exposed to the pollutant showed an increase in the conversion of LC3, a protein involved in the autophagic process. Incubation of A549 lung cells with dibenzofuran caused an increase in Lysotracker Red staining, indicating an increase in lysosomal vacuoles content. These results suggest that exposure to dibenzofuran affects lung mitochondrial phosphorylative function, causing an increase in the population of dysfunctional mitochondria and an impairment in the energetic status maintenance, therefore stimulating autophagy as a possible rescue mechanism in this cell line.


Assuntos
Autofagia/efeitos dos fármacos , Benzofuranos/toxicidade , Poluentes Ambientais/toxicidade , Pulmão/citologia , Nucleotídeos de Adenina/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Western Blotting , Morte Celular/efeitos dos fármacos , Linhagem Celular , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/ultraestrutura , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Corantes , Relação Dose-Resposta a Droga , Metabolismo Energético , Humanos , L-Lactato Desidrogenase/metabolismo , Pulmão/efeitos dos fármacos , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos , Espécies Reativas de Oxigênio/metabolismo , Sais de Tetrazólio , Tiazóis
18.
Biochim Biophys Acta ; 1822(2): 185-95, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22027215

RESUMO

Berberine (BBR) has recently been shown to improve insulin sensitivity in rodent models of insulin resistance. Although this effect was explained partly through an observed activation of AMP-activated protein kinase (AMPK), the upstream and downstream mediators of this phenotype were not explored. Here, we show that BBR supplementation reverts mitochondrial dysfunction induced by High Fat Diet (HFD) and hyperglycemia in skeletal muscle, in part due to an increase in mitochondrial biogenesis. Furthermore, we observe that the prevention of mitochondrial dysfunction by BBR, the increase in mitochondrial biogenesis, as well as BBR-induced AMPK activation, are blocked in cells in which SIRT1 has been knocked-down. Taken together, these data reveal an important role for SIRT1 and mitochondrial biogenesis in the preventive effects of BBR on diet-induced insulin resistance.


Assuntos
Berberina/farmacologia , Dieta Hiperlipídica , Mitocôndrias Musculares/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Biogênese de Organelas , Sirtuína 1/metabolismo , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Linhagem Celular , Glucose/metabolismo , Hormônios/metabolismo , Hiperglicemia/metabolismo , Resistência à Insulina , Masculino , Camundongos , Mitocôndrias/metabolismo , Mitocôndrias Musculares/metabolismo , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Mioblastos/efeitos dos fármacos , Mioblastos/metabolismo , NAD/metabolismo , Obesidade/metabolismo , Fosforilação/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Sirtuína 1/genética
19.
Toxicol Mech Methods ; 21(8): 571-6, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21554085

RESUMO

Environmental pollutants, such as dioxins and furans, are extremely toxic and related with pulmonary diseases development. Impairment of mitochondrial function has been shown in pollutant-induced hepatic injury, but it has not been addressed in lungs, even though lung mitochondria are primary cellular targets for pollutants-induced toxicity. In isolated lung mitochondria, dibenzofuran significantly increased the lag phase preceding mitochondrial repolarization, suggesting a decrease in the efficiency of the mitochondrial phosphorylative system.


Assuntos
Benzofuranos/toxicidade , Pulmão/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Adenosina Trifosfatases/metabolismo , Animais , Citocromos c , Pulmão/citologia , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Potenciais da Membrana/efeitos dos fármacos , Consumo de Oxigênio , Permeabilidade , Suínos
20.
Toxicol In Vitro ; 25(3): 664-70, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21232593

RESUMO

The major toxicological concern associated with nanomaterials is the fact that some manufactured nanomaterials are redox active, and some particles transport across cell membranes, especially into mitochondria. Thus, evaluation of their toxicity upon acute exposure is essential. In this work, we evaluated the toxicity of silver nanoparticles (40 and 80 nm) and their effects in rat liver mitochondria bioenergetics. Wistar rat liver mitochondria demonstrate alterations in respiration and membrane potential capacities in the presence of either 40 or 80 nm silver nanoparticles. Our data demonstrated a statistically significant decrease in mitochondrial membrane potential, ADP-induced depolarization, and respiratory control ratio (RCR) upon exposure to silver nanoparticles. Our results show that silver nanoparticles cause impairment of mitochondrial function, due mainly to alterations of mitochondrial membrane permeability. This results in an uncoupling effect on the oxidative phosphorylation system. Thus, mitochondrial toxicity may have a central role in the toxicity resulting from exposure to silver nanoparticles.


Assuntos
Nanopartículas Metálicas/toxicidade , Mitocôndrias Hepáticas/efeitos dos fármacos , Compostos de Prata/toxicidade , Animais , Cálcio/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Nanopartículas Metálicas/ultraestrutura , Microscopia Eletrônica de Transmissão , Mitocôndrias Hepáticas/metabolismo , Dilatação Mitocondrial/efeitos dos fármacos , Consumo de Oxigênio/efeitos dos fármacos , Tamanho da Partícula , Ratos , Ratos Wistar , Testes de Toxicidade Aguda
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