RESUMEN
Astrocytes take up glucose from the bloodstream to provide energy to the brain, thereby allowing neuronal activity and behavioural responses1-5. By contrast, astrocytes are under neuronal control through specific neurotransmitter receptors5-7. However, whether the activation of astroglial receptors can directly regulate cellular glucose metabolism to eventually modulate behavioural responses is unclear. Here we show that activation of mouse astroglial type-1 cannabinoid receptors associated with mitochondrial membranes (mtCB1) hampers the metabolism of glucose and the production of lactate in the brain, resulting in altered neuronal functions and, in turn, impaired behavioural responses in social interaction assays. Specifically, activation of astroglial mtCB1 receptors reduces the phosphorylation of the mitochondrial complex I subunit NDUFS4, which decreases the stability and activity of complex I. This leads to a reduction in the generation of reactive oxygen species by astrocytes and affects the glycolytic production of lactate through the hypoxia-inducible factor 1 pathway, eventually resulting in neuronal redox stress and impairment of behavioural responses in social interaction assays. Genetic and pharmacological correction of each of these effects abolishes the effect of cannabinoid treatment on the observed behaviour. These findings suggest that mtCB1 receptor signalling can directly regulate astroglial glucose metabolism to fine-tune neuronal activity and behaviour in mice.
Asunto(s)
Astrocitos/metabolismo , Metabolismo Energético , Glucosa/metabolismo , Mitocondrias/metabolismo , Receptor Cannabinoide CB1/metabolismo , Animales , Astrocitos/citología , Astrocitos/efectos de los fármacos , Agonistas de Receptores de Cannabinoides/farmacología , Células Cultivadas , Dronabinol/farmacología , Complejo I de Transporte de Electrón/química , Complejo I de Transporte de Electrón/metabolismo , Metabolismo Energético/efectos de los fármacos , Glucólisis/efectos de los fármacos , Humanos , Factor 1 Inducible por Hipoxia/metabolismo , Ácido Láctico/metabolismo , Masculino , Ratones , Mitocondrias/efectos de los fármacos , Membranas Mitocondriales/metabolismo , Oxidación-Reducción , Fosforilación , Especies Reactivas de Oxígeno/metabolismo , Receptor Cannabinoide CB1/agonistas , Conducta SocialRESUMEN
Cellular activity in the brain depends on the high energetic support provided by mitochondria, the cell organelles which use energy sources to generate ATP. Acute cannabinoid intoxication induces amnesia in humans and animals, and the activation of type-1 cannabinoid receptors present at brain mitochondria membranes (mtCB1) can directly alter mitochondrial energetic activity. Although the pathological impact of chronic mitochondrial dysfunctions in the brain is well established, the involvement of acute modulation of mitochondrial activity in high brain functions, including learning and memory, is unknown. Here, we show that acute cannabinoid-induced memory impairment in mice requires activation of hippocampal mtCB1 receptors. Genetic exclusion of CB1 receptors from hippocampal mitochondria prevents cannabinoid-induced reduction of mitochondrial mobility, synaptic transmission and memory formation. mtCB1 receptors signal through intra-mitochondrial Gαi protein activation and consequent inhibition of soluble-adenylyl cyclase (sAC). The resulting inhibition of protein kinase A (PKA)-dependent phosphorylation of specific subunits of the mitochondrial electron transport system eventually leads to decreased cellular respiration. Hippocampal inhibition of sAC activity or manipulation of intra-mitochondrial PKA signalling or phosphorylation of the Complex I subunit NDUFS2 inhibit bioenergetic and amnesic effects of cannabinoids. Thus, the G protein-coupled mtCB1 receptors regulate memory processes via modulation of mitochondrial energy metabolism. By directly linking mitochondrial activity to memory formation, these data reveal that bioenergetic processes are primary acute regulators of cognitive functions.
Asunto(s)
Cannabinoides/efectos adversos , Trastornos de la Memoria/inducido químicamente , Memoria/efectos de los fármacos , Memoria/fisiología , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Adenilil Ciclasas/metabolismo , Animales , Cannabinoides/metabolismo , Respiración de la Célula/efectos de los fármacos , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Transporte de Electrón/efectos de los fármacos , Metabolismo Energético/efectos de los fármacos , Femenino , Subunidades alfa de la Proteína de Unión al GTP Gi-Go/metabolismo , Hipocampo/efectos de los fármacos , Hipocampo/metabolismo , Hipocampo/patología , Masculino , Trastornos de la Memoria/enzimología , Trastornos de la Memoria/metabolismo , Trastornos de la Memoria/patología , Ratones , Membranas Mitocondriales/efectos de los fármacos , Membranas Mitocondriales/enzimología , Membranas Mitocondriales/metabolismo , NADH Deshidrogenasa/metabolismo , Fosforilación Oxidativa/efectos de los fármacos , Receptor Cannabinoide CB1/deficiencia , Receptor Cannabinoide CB1/genética , Receptor Cannabinoide CB1/metabolismo , Transducción de Señal/efectos de los fármacos , Transmisión Sináptica/efectos de los fármacosRESUMEN
Hereditary spastic paraplegia, SPG31, is a rare neurological disorder caused by mutations in REEP1 gene encoding the microtubule-interacting protein, REEP1. The mechanism by which REEP1-dependent processes are linked with the disease is unclear. REEP1 regulates the morphology and trafficking of various organelles via interaction with the microtubules. In this study, we collected primary fibroblasts from SPG31 patients to investigate their mitochondrial morphology. We observed that the mitochondrial morphology in patient cells was highly tubular compared with control cells. We provide evidence that these morphological alterations are caused by the inhibition of mitochondrial fission protein, DRP1, due to the hyperphosphorylation of its serine 637 residue. This hyperphosphorylation is caused by impaired interactions between REEP1 and mitochondrial phosphatase PGAM5. Genetically or pharmacologically induced decrease of DRP1-S637 phosphorylation restores mitochondrial morphology in patient cells. Furthermore, ectopic expression of REEP1 carrying pathological mutations in primary neuronal culture targets REEP1 to the mitochondria. Mutated REEP1 proteins sequester mitochondria to the perinuclear region of the neurons and therefore, hamper mitochondrial transport along the axon. Considering the established role of mitochondrial distribution and morphology in neuronal health, our results support the involvement of a mitochondrial dysfunction in SPG31 pathology.
Asunto(s)
Núcleo Celular , GTP Fosfohidrolasas , Proteínas Asociadas a Microtúbulos , Mitocondrias , Proteínas Mitocondriales , Neuronas/metabolismo , Paraplejía Espástica Hereditaria , Animales , Núcleo Celular/genética , Núcleo Celular/metabolismo , Núcleo Celular/patología , Células Cultivadas , Dinaminas , Femenino , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , Humanos , Masculino , Proteínas de Transporte de Membrana/genética , Proteínas de Transporte de Membrana/metabolismo , Ratones , Proteínas Asociadas a Microtúbulos/genética , Proteínas Asociadas a Microtúbulos/metabolismo , Mitocondrias/metabolismo , Mitocondrias/patología , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Neuronas/patología , Fosfoproteínas Fosfatasas/genética , Fosfoproteínas Fosfatasas/metabolismo , Fosforilación/genética , Paraplejía Espástica Hereditaria/metabolismo , Paraplejía Espástica Hereditaria/patologíaRESUMEN
Identification of the mechanisms by which drugs of abuse cause neuronal dysfunction is essential for understanding the biological bases of their acute and long-lasting effects in the brain. Here, we performed real-time functional experiments of axonal transport of mitochondria to explore the role of in situ mitochondrial dysfunction in 3,4-methylenedioxymethamphetamine (MDMA; "ecstasy")-related brain actions. We showed that MDMA dramatically reduced mitochondrial trafficking in hippocampal neurons in a Tau-dependent manner, in which glycogen synthase kinase 3ß activity was implicated. Furthermore, we found that these trafficking abnormalities were rescued by over-expression of Mitofusin2 and dynamin-related protein 1, but not of Miro1. Given the relevance of mitochondrial targeting for neuronal function and neurotransmission, our data underscore a novel mechanism of action of MDMA that may contribute to our understanding of how this drug of abuse alters neuronal functioning.
Asunto(s)
Dinaminas/metabolismo , GTP Fosfohidrolasas/metabolismo , Mitocondrias/efectos de los fármacos , Dinámicas Mitocondriales/efectos de los fármacos , N-Metil-3,4-metilenodioxianfetamina/toxicidad , Neuronas/efectos de los fármacos , Proteínas tau/metabolismo , Animales , Transporte Axonal/efectos de los fármacos , Calcio/metabolismo , Células Cultivadas , Hipocampo/citología , Hipocampo/efectos de los fármacos , Hipocampo/embriología , Ratones Endogámicos C57BL , Mitocondrias/metabolismo , Neuronas/metabolismo , FosforilaciónRESUMEN
Astrocytes control brain activity via both metabolic processes and gliotransmission, but the physiological links between these functions are scantly known. Here we show that endogenous activation of astrocyte type-1 cannabinoid (CB1) receptors determines a shift of glycolysis towards the lactate-dependent production of D-serine, thereby gating synaptic and cognitive functions in male mice. Mutant mice lacking the CB1 receptor gene in astrocytes (GFAP-CB1-KO) are impaired in novel object recognition (NOR) memory. This phenotype is rescued by the gliotransmitter D-serine, by its precursor L-serine, and also by lactate and 3,5-DHBA, an agonist of the lactate receptor HCAR1. Such lactate-dependent effect is abolished when the astrocyte-specific phosphorylated-pathway (PP), which diverts glycolysis towards L-serine synthesis, is blocked. Consistently, lactate and 3,5-DHBA promoted the co-agonist binding site occupancy of CA1 post-synaptic NMDA receptors in hippocampal slices in a PP-dependent manner. Thus, a tight cross-talk between astrocytic energy metabolism and gliotransmission determines synaptic and cognitive processes.
Asunto(s)
Astrocitos , Cognición , Glucólisis , Ácido Láctico , Ratones Noqueados , Serina , Animales , Masculino , Astrocitos/metabolismo , Cognición/fisiología , Ratones , Ácido Láctico/metabolismo , Serina/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Receptores de N-Metil-D-Aspartato/genética , Hipocampo/metabolismo , Sinapsis/metabolismo , Ratones Endogámicos C57BL , Receptores Acoplados a Proteínas G/metabolismo , Receptores Acoplados a Proteínas G/genéticaRESUMEN
Corticosteroid-mediated stress responses require the activation of complex brain circuits involving mitochondrial activity, but the underlying cellular and molecular mechanisms are scantly known. The endocannabinoid system is implicated in stress coping, and it can directly regulate brain mitochondrial functions via type 1 cannabinoid (CB1) receptors associated with mitochondrial membranes (mtCB1). In this study, we show that the impairing effect of corticosterone in the novel object recognition (NOR) task in mice requires mtCB1 receptors and the regulation of mitochondrial calcium levels in neurons. Different brain circuits are modulated by this mechanism to mediate the impact of corticosterone during specific phases of the task. Thus, whereas corticosterone recruits mtCB1 receptors in noradrenergic neurons to impair NOR consolidation, mtCB1 receptors in local hippocampal GABAergic interneurons are required to inhibit NOR retrieval. These data reveal unforeseen mechanisms mediating the effects of corticosteroids during different phases of NOR, involving mitochondrial calcium alterations in different brain circuits.
Asunto(s)
Neuronas Adrenérgicas , Corticosterona , Ratones , Animales , Corticosterona/farmacología , Receptores de Cannabinoides , Calcio , Mitocondrias , Endocannabinoides , Receptor Cannabinoide CB1 , Hipocampo/fisiologíaRESUMEN
Cannabis use disorder (CUD) is widespread, and there is no pharmacotherapy to facilitate its treatment. AEF0117, the first of a new pharmacological class, is a signaling-specific inhibitor of the cannabinoid receptor 1 (CB1-SSi). AEF0117 selectively inhibits a subset of intracellular effects resulting from Δ9-tetrahydrocannabinol (THC) binding without modifying behavior per se. In mice and non-human primates, AEF0117 decreased cannabinoid self-administration and THC-related behavioral impairment without producing significant adverse effects. In single-ascending-dose (0.2 mg, 0.6 mg, 2 mg and 6 mg; n = 40) and multiple-ascending-dose (0.6 mg, 2 mg and 6 mg; n = 24) phase 1 trials, healthy volunteers were randomized to ascending-dose cohorts (n = 8 per cohort; 6:2 AEF0117 to placebo randomization). In both studies, AEF0117 was safe and well tolerated (primary outcome measurements). In a double-blind, placebo-controlled, crossover phase 2a trial, volunteers with CUD were randomized to two ascending-dose cohorts (0.06 mg, n = 14; 1 mg, n = 15). AEF0117 significantly reduced cannabis' positive subjective effects (primary outcome measurement, assessed by visual analog scales) by 19% (0.06 mg) and 38% (1 mg) compared to placebo (P < 0.04). AEF0117 (1 mg) also reduced cannabis self-administration (P < 0.05). In volunteers with CUD, AEF0117 was well tolerated and did not precipitate cannabis withdrawal. These data suggest that AEF0117 is a safe and potentially efficacious treatment for CUD.ClinicalTrials.gov identifiers: NCT03325595 , NCT03443895 and NCT03717272 .
Asunto(s)
Cannabis , Alucinógenos , Abuso de Marihuana , Síndrome de Abstinencia a Sustancias , Animales , Ratones , Método Doble Ciego , Dronabinol/efectos adversos , Alucinógenos/uso terapéutico , Ensayos Clínicos Controlados Aleatorios como Asunto , Síndrome de Abstinencia a Sustancias/tratamiento farmacológicoRESUMEN
Mitochondrial calcium handling is a particularly active research area in the neuroscience field, as it plays key roles in the regulation of several functions of the central nervous system, such as synaptic transmission and plasticity, astrocyte calcium signaling, neuronal activity In the last few decades, a panel of techniques have been developed to measure mitochondrial calcium dynamics, relying mostly on photonic microscopy, and including synthetic sensors, hybrid sensors and genetically encoded calcium sensors. The goal of this review is to endow the reader with a deep knowledge of the historical and latest tools to monitor mitochondrial calcium events in the brain, as well as a comprehensive overview of the current state of the art in brain mitochondrial calcium signaling. We will discuss the main calcium probes used in the field, their mitochondrial targeting strategies, their key properties and major drawbacks. In addition, we will detail the main roles of mitochondrial calcium handling in neuronal tissues through an extended report of the recent studies using mitochondrial targeted calcium sensors in neuronal and astroglial cells, in vitro and in vivo.
Asunto(s)
Señalización del Calcio , Calcio , Encéfalo/diagnóstico por imagen , Encéfalo/metabolismo , Calcio/metabolismo , Mitocondrias/metabolismo , Neuronas/metabolismoRESUMEN
The endocannabinoid system (ECS) is involved in a variety of brain functions, mainly through the activation of the type-1 cannabinoid receptors (CB1R). CB1R are highly expressed throughout the brain at different structural, cellular and subcellular locations and its activity and expression levels have a direct impact in synaptic activity and behavior. In the last few decades, astrocytes have arisen as active players of brain physiology through their participation in the tripartite synapse and through their metabolic interaction with neurons. Here, we discuss some of the mechanisms by which astroglial CB1R at different subcellular locations, regulate astrocyte calcium signals and have an impact on gliotransmission and metabolic regulation. In addition, we discuss evidence pointing at astrocytes as potential important sources of endocannabinoid synthesis and release. Thus, we summarize recent findings that add further complexity and establish that the ECS is a fundamental effector of astrocyte functions in the brain. This article is part of the special issue on 'Cannabinoids'.
Asunto(s)
Astrocitos/metabolismo , Encéfalo/metabolismo , Endocannabinoides/metabolismo , Neuronas/metabolismo , Receptor Cannabinoide CB1/metabolismo , Animales , Sinapsis/metabolismo , Transmisión Sináptica/fisiologíaRESUMEN
ARMCX3 is encoded by a member of the Armcx gene family and is known to be involved in nervous system development and function. We found that ARMCX3 is markedly upregulated in mouse liver in response to high lipid availability, and that hepatic ARMCX3 is upregulated in patients with NAFLD and hepatocellular carcinoma (HCC). Mice were subjected to ARMCX3 invalidation (inducible ARMCX3 knockout) and then exposed to a high-fat diet and diethylnitrosamine-induced hepatocarcinogenesis. The effects of experimental ARMCX3 knockdown or overexpression in HCC cell lines were also analyzed. ARMCX3 invalidation protected mice against high-fat-diet-induced NAFLD and chemically induced hepatocarcinogenesis. ARMCX3 invalidation promoted apoptotic cell death and macrophage infiltration in livers of diethylnitrosamine-treated mice maintained on a high-fat diet. ARMCX3 downregulation reduced the viability, clonality and migration of HCC cell lines, whereas ARMCX3 overexpression caused the reciprocal effects. SOX9 was found to mediate the effects of ARMCX3 in hepatic cells, with the SOX9 interaction required for the effects of ARMCX3 on hepatic cell proliferation. In conclusion, ARMCX3 is identified as a novel molecular actor in liver physiopathology and carcinogenesis. ARMCX3 downregulation appears to protect against hepatocarcinogenesis, especially under conditions of high dietary lipid-mediated hepatic insult.
RESUMEN
Intracellular calcium signaling underlies the astroglial control of synaptic transmission and plasticity. Mitochondria-endoplasmic reticulum contacts (MERCs) are key determinants of calcium dynamics, but their functional impact on astroglial regulation of brain information processing is unexplored. We found that the activation of astrocyte mitochondrial-associated type-1 cannabinoid (mtCB1) receptors determines MERC-dependent intracellular calcium signaling and synaptic integration. The stimulation of mtCB1 receptors promotes calcium transfer from the endoplasmic reticulum to mitochondria through a specific molecular cascade, involving the mitochondrial calcium uniporter (MCU). Physiologically, mtCB1-dependent mitochondrial calcium uptake determines the dynamics of cytosolic calcium events in astrocytes upon endocannabinoid mobilization. Accordingly, electrophysiological recordings in hippocampal slices showed that conditional genetic exclusion of mtCB1 receptors or dominant-negative MCU expression in astrocytes blocks lateral synaptic potentiation, through which astrocytes integrate the activity of distant synapses. Altogether, these data reveal an endocannabinoid link between astroglial MERCs and the regulation of brain network functions.
Asunto(s)
Astrocitos/metabolismo , Calcio/metabolismo , Cannabinoides/metabolismo , Retículo Endoplásmico/metabolismo , Mitocondrias/metabolismo , Receptores de Cannabinoides/fisiología , Sinapsis/fisiología , Animales , Astrocitos/citología , Canales de Calcio/fisiología , Señalización del Calcio , Células Cultivadas , Hipocampo/metabolismo , Homeostasis , Ratones , Ratones Endogámicos C57BL , Plasticidad Neuronal , Transmisión SinápticaRESUMEN
Recent evidence indicates that, besides its canonical localization at cell plasma membranes, the type-1 cannabinoid receptor, CB1 is functionally present at brain and muscle mitochondrial membranes (mtCB1). Through mtCB1 receptors, cannabinoids can directly regulate intramitochondrial signaling and respiration. This new and surprising discovery paves the way to new potential fields of research, dealing with the direct impact of G protein-coupled receptors on bioenergetic processes and its functional implications. In this chapter, we summarize some key experimental approaches established in our laboratories to identify anatomical, biochemical, and functional features of mtCB1 receptors in the brain. In particular, we describe the procedures to obtain reliable and controlled detection of mtCB1 receptors by immunogold electromicroscopy and by immunoblotting methods. Then, we address the study of direct cannabinoid effects on the electron transport system and oxidative phosphorylation. Finally, we present a functional example of the impact of mtCB1 receptors on mitochondrial mobility in cultured neurons. Considering the youth of the field, these methodological approaches will very likely be improved and refined in the future, but this chapter aims at presenting the methods that are currently used and, in particular, at underlining the need of rigorous controls to obtain reliable results. We hope that this chapter might help scientists becoming interested in this new and exciting field of research.
Asunto(s)
Encéfalo/metabolismo , Mitocondrias/metabolismo , Receptor Cannabinoide CB1/metabolismo , Animales , Western Blotting , Encéfalo/ultraestructura , Respiración de la Célula , Complejo I de Transporte de Electrón/metabolismo , Inmunohistoquímica , Inmunoprecipitación , Ratones Noqueados , Microscopía Electrónica de Transmisión , Mitocondrias/ultraestructura , Membranas Mitocondriales/metabolismo , Membranas Mitocondriales/ultraestructura , Consumo de Oxígeno , Receptor Cannabinoide CB1/genética , Receptor Cannabinoide CB1/aislamiento & purificaciónRESUMEN
3,4-Methylenedioxymethamphetamine (MDMA; "ecstasy") is a potentially neurotoxic recreational drug of abuse. Though the mechanisms involved are still not completely understood, formation of reactive metabolites and mitochondrial dysfunction contribute to MDMA-related neurotoxicity. Neuronal mitochondrial trafficking, and their targeting to synapses, is essential for proper neuronal function and survival, rendering neurons particularly vulnerable to mitochondrial dysfunction. Indeed, MDMA-associated disruption of Ca(2+) homeostasis and ATP depletion have been described in neurons, thus suggesting possible MDMA interference on mitochondrial dynamics. In this study, we performed real-time functional experiments of mitochondrial trafficking to explore the role of in situ mitochondrial dysfunction in MDMA's neurotoxic actions. We show that the mixture of MDMA and six of its major in vivo metabolites, each compound at 10µM, impaired mitochondrial trafficking and increased the fragmentation of axonal mitochondria in cultured hippocampal neurons. Furthermore, the overexpression of mitofusin 2 (Mfn2) or dynamin-related protein 1 (Drp1) K38A constructs almost completely rescued the trafficking deficits caused by this mixture. Finally, in hippocampal neurons overexpressing a Mfn2 mutant, Mfn2 R94Q, with impaired fusion and transport properties, it was confirmed that a dysregulation of mitochondrial fission/fusion events greatly contributed to the reported trafficking phenotype. In conclusion, our study demonstrated, for the first time, that the mixture of MDMA and its metabolites, at concentrations relevant to the in vivo scenario, impaired mitochondrial trafficking and increased mitochondrial fragmentation in hippocampal neurons, thus providing a new insight in the context of "ecstasy"-induced neuronal injury.
Asunto(s)
Transporte Axonal/efectos de los fármacos , Hipocampo/efectos de los fármacos , Dinámicas Mitocondriales/efectos de los fármacos , N-Metil-3,4-metilenodioxianfetamina/metabolismo , N-Metil-3,4-metilenodioxianfetamina/toxicidad , Neuronas/efectos de los fármacos , Adenosina Trifosfato/metabolismo , Animales , Calcio/metabolismo , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Relación Dosis-Respuesta a Droga , GTP Fosfohidrolasas/metabolismo , Hipocampo/metabolismo , Ratones , Neuronas/metabolismo , Síndromes de Neurotoxicidad/etiología , Síndromes de Neurotoxicidad/metabolismo , RatasRESUMEN
The regulation of mitochondrial dynamics is vital in complex cell types, such as neurons, that transport and localize mitochondria in high energy-demanding cell domains. The Armcx3 gene encodes a mitochondrial-targeted protein (Alex3) that contains several arm-like domains. In a previous study we showed that Alex3 protein regulates mitochondrial aggregation and trafficking. Here we studied the contribution of Wnt proteins to the mitochondrial aggregation and dynamics regulated by Alex3. Overexpression of Alex3 in HEK293 cells caused a marked aggregation of mitochondria, which was attenuated by treatment with several Wnts. We also found that this decrease was caused by Alex3 degradation induced by Wnts. While the Wnt canonical pathway did not alter the pattern of mitochondrial aggregation induced by Alex3, we observed that the Wnt/PKC non-canonical pathway regulated both mitochondrial aggregation and Alex3 protein levels, thereby rendering a mitochondrial phenotype and distribution similar to control patterns. Our data suggest that the Wnt pathway regulates mitochondrial distribution and dynamics through Alex3 protein degradation.
Asunto(s)
Proteínas del Dominio Armadillo/metabolismo , Mitocondrias/metabolismo , Dinámicas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Proteína Quinasa C/metabolismo , Proteínas Wnt/metabolismo , Vía de Señalización Wnt , Secuencias de Aminoácidos , Proteínas del Dominio Armadillo/genética , Regulación de la Expresión Génica , Genes Reporteros , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Células HEK293 , Humanos , Mitocondrias/genética , Proteínas Mitocondriales/genética , Datos de Secuencia Molecular , Naftalenos/farmacología , Proteína Quinasa C/genética , Inhibidores de Proteínas Quinasas/farmacología , Estabilidad Proteica , Estructura Terciaria de Proteína , Proteolisis , Proteínas Wnt/genéticaRESUMEN
Brain function requires neuronal activity-dependent energy consumption. Neuronal energy supply is controlled by molecular mechanisms that regulate mitochondrial dynamics, including Kinesin motors and Mitofusins, Miro1-2 and Trak2 proteins. Here we show a new protein family that localizes to the mitochondria and controls mitochondrial dynamics. This family of proteins is encoded by an array of armadillo (Arm) repeat-containing genes located on the X chromosome. The Armcx cluster is unique to Eutherian mammals and evolved from a single ancestor gene (Armc10). We show that these genes are highly expressed in the developing and adult nervous system. Furthermore, we demonstrate that Armcx3 expression levels regulate mitochondrial dynamics and trafficking in neurons, and that Alex3 interacts with the Kinesin/Miro/Trak2 complex in a Ca(2+)-dependent manner. Our data provide evidence of a new Eutherian-specific family of mitochondrial proteins that controls mitochondrial dynamics and indicate that this key process is differentially regulated in the brain of higher vertebrates.