Mitochondrial roles of the psychiatric disease risk factor DISC1

NRF-2α and mitophagy underlie enhanced mitochondrial functions and biogenesis induced by T-2 toxin in GH3 cells

T-2 toxin is a natural contaminant in grain cereals produced by species of Fusarium. Studies indicate that T-2 toxin can positively affect mitochondrial function, but the underlying mechanism is unclear. In this study, we examined the role of nuclear respiratory factor 2α (NRF-2α) in T-2 toxin-activated mitochondrial biogenesis and the direct target genes of NRF-2α. Furthermore, we investigated T-2 toxin-induced autophagy and mitophagy, and the role of mitophagy in changes in mitochondrial function and apoptosis. It was found that T-2 toxin significantly increased NRF-2α levels and nuclear localization of NRF-2α was induced. NRF-2α deletion significantly increased the production of reactive oxygen species (ROS), abrogated T-2 toxin-induced increases in ATP and mitochondrial complex I activity, and inhibited the mitochondrial DNA copy number. Meanwhile, With chromatin immunoprecipitation sequencing (ChIP-Seq), various novel NRF-2α target genes were identified, such as mitochondrial iron-sulphur subunits (Ndufs 3,7) and mitochondrial transcription factors (Tfam, Tfb1m, and Tfb2m). Some target genes were also involved in mitochondrial fusion and fission (Drp1), mitochondrial translation (Yars2) and splicing (Ddx55), and mitophagy. Further studies showed that T-2 toxin induced Atg5 dependent autophagy and Atg5/PINK1-dependent mitophagy. In addition, mitophagy defects increase ROS production, inhibit ATP levels and the expression of genes related to mitochondrial dynamics, and promote apoptosis in the presence of T-2 toxins. Altogether, these results suggest that NRF-2α plays a critical role in promoting mitochondrial function and biogenesis through regulation of mitochondrial genes, and, interestingly, mitophagy caused by T-2 toxin positively affected mitochondrial function and protected cell survival against T-2 toxin.

Roles of neuronal toll-like receptors in neuropathic pain and central nervous system injuries and diseases

Toll-like receptors (TLRs) are innate immune receptors that are expressed in immune cells as well as glia and neurons of the central and peripheral nervous systems. They are best known for their role in the host defense in response to pathogens and for the induction of inflammation in infectious and non-infectious diseases. In the central nervous system (CNS), TLRs modulate glial and neuronal functions as well as innate immunity and neuroinflammation under physiological or pathophysiological conditions. The majority of the studies on TLRs in CNS pathologies investigated their overall contribution without focusing on a particular cell type, or they analyzed TLRs in glia and infiltrating immune cells in the context of neuroinflammation and cellular activation. The role of neuronal TLRs in CNS diseases and injuries has received little attention and remains underappreciated. The primary goal of this review is to summarize findings demonstrating the pivotal and unique roles of neuronal TLRs in neuropathic pain, Alzheimer's disease, Parkinson's disease and CNS injuries. We discuss how the current findings warrant future investigations to better define the specific contributions of neuronal TLRs to these pathologies. We underline the paucity of information regarding the role of neuronal TLRs in other neurodegenerative, demyelinating, and psychiatric diseases. We draw attention to the importance of broadening research on neuronal TLRs in view of emerging evidence demonstrating their distinctive functional properties.

Clinical translational neuroimaging of the antioxidant effect of N-acetylcysteine on neural microstructure

PURPOSE

Oxidative stress and downstream effectors have emerged as important pathological processes that drive psychiatric illness, suggesting that antioxidants may have a therapeutic role in psychiatric disease. However, no imaging biomarkers are currently available to track therapeutic response. The purpose of this study was to examine whether advanced DWI techniques are able to sensitively detect the potential therapeutic effects of the antioxidant N-acetylcysteine (NAC) in a Disc1 svΔ2 preclinical rat model of psychiatric illness.

METHODS

Male and female Disc1 svΔ2 rats and age-matched, sex-matched Sprague-Dawley wild-type controls were treated with a saline vehicle or NAC before ex vivo MRI acquisition at P50. Imaging data were fit to DTI and neurite orientation dispersion and density imaging models and analyzed for region-specific changes in quantitative diffusion metrics. Brains were further processed for cellular quantification of microglial density and morphology. All experiments were repeated for Disc1 svΔ2 rats exposed to chronic early-life stress to test how gene-environment interactions might alter effectiveness of NAC therapy.

RESULTS

The DTI and neurite orientation dispersion and density imaging analyses demonstrated amelioration of early-life, sex-specific neural microstructural deficits with concomitant differences in microglial morphology across multiple brain regions relevant to neuropsychiatric illness with NAC treatment, but only in male Disc1 svΔ2 rats. Addition of chronic early-life stress reduced the ability of NAC to restore microstructural deficits.

CONCLUSION

These findings provide evidence for a treatment pathway targeting endogenous antioxidant capacity, and the clinical translational utility of neurite orientation dispersion and density imaging microstructural imaging to sensitively detect microstructural alterations resulting from antioxidant treatment.

Mitochondrial Miro GTPases coordinate mitochondrial and peroxisomal dynamics

Mitochondria and peroxisomes are highly dynamic, multifunctional organelles. Both perform key roles for cellular physiology and homoeostasis by mediating bioenergetics, biosynthesis, and/or signalling. To support cellular function, they must be properly distributed, of proper size, and be able to interact with other organelles. Accumulating evidence suggests that the small atypical GTPase Miro provides a central signalling node to coordinate mitochondrial as well as peroxisomal dynamics. In this review, I summarize our current understanding of Miro-dependent functions and molecular mechanisms underlying the proper distribution, size and function of mitochondria and peroxisomes.

Mitophagy in Human Diseases

Mitophagy is a selective autophagic process, essential for cellular homeostasis, that eliminates dysfunctional mitochondria. Activated by inner membrane depolarization, it plays an important role during development and is fundamental in highly differentiated post-mitotic cells that are highly dependent on aerobic metabolism, such as neurons, muscle cells, and hepatocytes. Both defective and excessive mitophagy have been proposed to contribute to age-related neurodegenerative diseases, such as Parkinson’s and Alzheimer’s diseases, metabolic diseases, vascular complications of diabetes, myocardial injury, muscle dystrophy, and liver disease, among others. Pharmacological or dietary interventions that restore mitophagy homeostasis and facilitate the elimination of irreversibly damaged mitochondria, thus, could serve as potential therapies in several chronic diseases. However, despite extraordinary advances in this field, mainly derived from in vitro and preclinical animal models, human applications based on the regulation of mitochondrial quality in patients have not yet been approved. In this review, we summarize the key selective mitochondrial autophagy pathways and their role in prevalent chronic human diseases and highlight the potential use of specific interventions.

Miro (Mitochondrial Rho GTPase), a key player of mitochondrial axonal transport and mitochondrial dynamics in neurodegenerative diseases

Miro (mitochondrial Rho GTPases) a mitochondrial outer membrane protein, plays a vital role in the microtubule-based mitochondrial axonal transport, mitochondrial dynamics (fusion and fission) and Mito-Ca²⁺ homeostasis. It forms a major protein complex with Milton (an adaptor protein), kinesin and dynein (motor proteins), and facilitates bidirectional mitochondrial axonal transport such as anterograde and retrograde transport. By forming this protein complex, Miro facilitates the mitochondrial axonal transport and fulfills the neuronal energy demand, maintain the mitochondrial homeostasis and neuronal survival. It has been demonstrated that altered mitochondrial biogenesis, improper mitochondrial axonal transport, and mitochondrial dynamics are the early pathologies associated with most of the neurodegenerative diseases (NDs). Being the sole mitochondrial outer membrane protein associated with mitochondrial axonal transport-related processes, Miro proteins can be one of the key players in various NDs such as Alzheimer's disease (AD), Parkinson's disease (PD), Amyotrophic lateral sclerosis (ALS) and Huntington's disease (HD). Thus, in the current review, we have discussed the evolutionarily conserved Miro proteins and its role in the pathogenesis of the various NDs. From this, we indicated that Miro proteins may act as a potential target for a novel therapeutic intervention for the treatment of various NDs.

DISC1 Regulates Mitochondrial Trafficking in a Miro1-GTP-Dependent Manner

The disrupted in schizophrenia 1 (DISC1) protein is implicated in major mental illnesses including schizophrenia and bipolar disorder. A key feature of psychiatric disease is aberrant synaptic communication. Correct synaptic transmission is dependent on spatiotemporally regulated energy provision and calcium buffering. This can be achieved by precise distribution of mitochondria throughout the elaborate architecture of the neuron. Central to this process is the calcium sensor and GTPase Miro1, which allows mitochondrial trafficking by molecular motors. While the role of Miro1-calcium binding in mitochondrial transport is well described, far less is known regarding the functions of the two GTPase domains. Here, we investigate the effects of a psychiatric disease-associated mutation in DISC1 on mitochondrial trafficking. We show that this DISC1 mutation impairs Miro1’s ability to transport mitochondria. We also demonstrate the necessity of the first Miro1 GTPase domain in determining direction of mitochondrial transport and the involvement of DISC1 in this process. Finally, we describe the effects of mutant DISC1 on positioning of mitochondria at synapses.

Mitochondria, endoplasmic reticulum and innate immune dysfunction in mood disorders: Do Mitochondria-Associated Membranes (MAMs) play a role?

Mood disorders like major depression and bipolar disorder (BD) are among the most prevalent forms of mental illness. Current knowledge of the neurobiology and pathophysiology of these disorders is still modest and clear biological markers are still missing. Thus, a better understanding of the underlying pathophysiological mechanisms to identify potential therapeutic targets is a prerequisite for the design of new drugs as well as to develop biomarkers that help in a more accurate and earlier diagnosis. Multiple pieces of evidence including genetic and neuro-imaging studies suggest that mood disorders are associated with abnormalities in endoplasmic-reticulum (ER)-related stress responses, mitochondrial function and calcium signalling. Furthermore, deregulation of the innate immune response has been described in patients diagnosed with mood disorders, including depression and BD. These disease-related events are associated with functions localized to a subdomain of the ER, known as Mitochondria-Associated Membranes (MAMs), which are lipid rafts-like domains that connect mitochondria and ER, both physically and biochemically. This review will outline the current understanding of the role of mitochondria and ER dysfunction under pathological brain conditions, particularly in major depressive disorder (MDD) and BD, that support the hypothesis that MAMs can act in these mood disorders as the link connecting ER-related stress response and mitochondrial impairment, as well as a mechanisms behind sterile inflammation arising from deregulation of innate immune responses. The role of MAMs in the pathophysiology of these pathologies and its potential relevance as a potential therapeutic target will be discussed.

Metabolic Changes in Synaptosomes in an Animal Model of Schizophrenia Revealed by 1H and 1H,13C NMR Spectroscopy

Synaptosomes are isolated nerve terminals that contain synaptic components, including neurotransmitters, metabolites, adhesion/fusion proteins, and nerve terminal receptors. The essential role of synaptosomes in neurotransmission has stimulated keen interest in understanding both their proteomic and metabolic composition. Mass spectrometric (MS) quantification of synaptosomes has illuminated their proteomic composition, but the determination of the metabolic composition by MS has been met with limited success. In this study, we report a proof-of-concept application of one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy for analyzing the metabolic composition of synaptosomes. We utilize this approach to compare the metabolic composition synaptosomes from a wild-type rat with that from a newly generated genetic rat model (Disc1 svΔ2), which qualitatively recapitulates clinically observed early DISC1 truncations associated with schizophrenia. This study demonstrates the feasibility of using NMR spectroscopy to identify and quantify metabolites within synaptosomal fractions.

Regulation and roles of mitophagy at synapses

Maintenance of synaptic homeostasis is a challenging task, due to the intricate spatial organization and intense activity of synapses. Typically, synapses are located far away from the neuronal cell body, where they orchestrate neuronal signalling and communication, through neurotransmitter release. Stationary mitochondria provide energy required for synaptic vesicle cycling, and preserve ionic balance by buffering intercellular calcium at synapses. Thus, synaptic homeostasis is critically dependent on proper mitochondrial function. Indeed, defective mitochondrial metabolism is a common feature of several neurodegenerative and psychiatric disorders, including Alzheimer's disease (AD), Parkinson's disease (PD), bipolar disorders and schizophrenia among others, which are also accompanied by excessive synaptic abnormalities. Specialized and compartmentalized quality control mechanisms have evolved to restore and maintain synaptic energy metabolism. Here, we survey recent advances towards the elucidation of the pivotal role of mitochondria in neurotransmission and implicating mitophagy in the maintenance of synaptic homeostasis during ageing.

Tourette Syndrome Risk Genes Regulate Mitochondrial Dynamics, Structure, and Function

Gilles de la Tourette syndrome (GTS) is a neurodevelopmental disorder characterized by motor and vocal tics with an estimated prevalence of 1% in children and adolescents. GTS has high rates of inheritance with many rare mutations identified. Apart from the role of the neurexin trans-synaptic connexus (NTSC) little has been confirmed regarding the molecular basis of GTS. The NTSC pathway regulates neuronal circuitry development, synaptic connectivity and neurotransmission. In this study we integrate GTS mutations into mitochondrial pathways that also regulate neuronal circuitry development, synaptic connectivity and neurotransmission. Many deleterious mutations in GTS occur in genes with complementary and consecutive roles in mitochondrial dynamics, structure and function (MDSF) pathways. These genes include those involved in mitochondrial transport (NDE1, DISC1, OPA1), mitochondrial fusion (OPA1), fission (ADCY2, DGKB, AMPK/PKA, RCAN1, PKC), mitochondrial metabolic and bio-energetic optimization (IMMP2L, MPV17, MRPL3, MRPL44). This study is the first to develop and describe an integrated mitochondrial pathway in the pathogenesis of GTS. The evidence from this study and our earlier modeling of GTS molecular pathways provides compounding support for a GTS deficit in mitochondrial supply affecting neurotransmission.

Evidence of association of the DISC1 interactome gene set with schizophrenia from GWAS

DISC1 was discovered as a gene disrupted by a balanced translocation in a large pedigree that segregated with major mental disorders, including schizophrenia. Further attempts to find genetic association with schizophrenia were inconclusive. Most of the biology of DISC1 was inferred from the functionality of its protein partners. Recently, a gene set constituted by DISC1 and several of its partners has been associated with cognitive performance during development, a well-known schizophrenia endophenotype, by means of burden test of rare disruptive variants. Here, we performed a gene set analysis using common variants from the largest schizophrenia genome-wide association study of the Psychiatric Genomics Consortium to test if this gene set is associated with schizophrenia. The main test was based on the MAGMA software. Several additional tests were performed to analyze the robustness of the main findings. The DISC1 interactome gene set was associated with schizophrenia (P = .0056), confirmed by an additional method (INRICH). This association was robust to removal of the major histocompatibility complex region, different definitions of gene boundaries, or different statistical gene models. Conditional analysis revealed that the association was not solely explained by higher expression in brain. Three genes from the gene set, CLIC1, DST, and PDE4B, were associated with schizophrenia at the gene level. Consideration of other DISC1 interactome gene sets revealed the importance of gene set definition. Therefore, we present the first evidence from genome-wide association studies of the role of DISC1 and interacting partners in schizophrenia susceptibility, reconciling genetic and molecular biology data.

Kinase network dysregulation in a human induced pluripotent stem cell model of DISC1 schizophrenia

Protein kinases orchestrate signal transduction pathways involved in central nervous system functions ranging from neurodevelopment to synaptic transmission and plasticity. Abnormalities in kinase-mediated signaling are involved in the pathophysiology of neurological disorders, including neuropsychiatric disorders. Here, we expand on the hypothesis that kinase networks are dysregulated in schizophrenia. We investigated changes in serine/threonine kinase activity in cortical excitatory neurons differentiated from induced pluripotent stem cells (iPSCs) from a schizophrenia patient presenting with a 4 bp mutation in the disrupted in schizophrenia 1 (DISC1) gene and a corresponding control. Using kinome peptide arrays, we demonstrate large scale abnormalities in DISC1 cells, including a global depression of serine/threonine kinase activity, and changes in activity of kinases, including AMP-activated protein kinase (AMPK), extracellular signal-regulated kinases (ERK), and thousand-and-one amino acid (TAO) kinases. Using isogenic cell lines in which the DISC1 mutation is either introduced in the control cell line, or rescued in the schizophrenia cell line, we ascribe most of these changes to a direct effect of the presence of the DISC1 mutation. Investigating the gene expression signatures downstream of the DISC1 kinase network, and mapping them on perturbagen signatures obtained from the Library of Integrated Network-based Cellular Signatures (LINCS) database, allowed us to propose novel drug targets able to reverse the DISC1 kinase dysregulation gene expression signature. Altogether, our findings provide new insight into abnormalities of kinase networks in schizophrenia and suggest possible targets for disease intervention.

Mitochondrial function and abnormalities implicated in the pathogenesis of ASD

Mitochondria are the powerhouse that generate over 90% of the ATP produced in cells. In addition to its role in energy production, the mitochondrion also plays a major role in carbohydrate, fatty acid, amino acid and nucleotide metabolism, programmed cell death (apoptosis), generation of and protection against reactive oxygen species (ROS), immune response, regulation of intracellular calcium ion levels and even maintenance of gut microbiota. With its essential role in bio-energetic as well as non-energetic biological processes, it is not surprising that proper cellular, tissue and organ function is dependent upon proper mitochondrial function. Accordingly, mitochondrial dysfunction has been shown to be directly linked to a variety of medical disorders, particularly neuromuscular disorders and increasing evidence has linked mitochondrial dysfunction to neurodegenerative and neurodevelopmental disorders such as Alzheimer's Disease (AD), Parkinson's Disease (PD), Rett Syndrome (RS) and Autism Spectrum Disorders (ASD). Over the last 40 years there has been a dramatic increase in the diagnosis of ASD and, more recently, an increasing body of evidence indicates that mitochondrial dysfunction plays an important role in ASD development. In this review, the latest evidence linking mitochondrial dysfunction and abnormalities in mitochondrial DNA (mtDNA) to the pathogenesis of autism will be presented. This review will also summarize the results of several recent `approaches used for improving mitochondrial function that may lead to new therapeutic approaches to managing and/or treating ASD.

Systems Analysis of the 22q11.2 Microdeletion Syndrome Converges on a Mitochondrial Interactome Necessary for Synapse Function and Behavior

Neurodevelopmental disorders offer insight into synaptic mechanisms. To unbiasedly uncover these mechanisms, we studied the 22q11.2 syndrome, a recurrent copy number variant, which is the highest schizophrenia genetic risk factor. We quantified the proteomes of 22q11.2 mutant human fibroblasts from both sexes and mouse brains carrying a 22q11.2-like defect, Df(16)A+/- Molecular ontologies defined mitochondrial compartments and pathways as some of top ranked categories. In particular, we identified perturbations in the SLC25A1-SLC25A4 mitochondrial transporter interactome as associated with the 22q11.2 genetic defect. Expression of SLC25A1-SLC25A4 interactome components was affected in neuronal cells from schizophrenia patients. Furthermore, hemideficiency of the Drosophila SLC25A1 or SLC25A4 orthologues, dSLC25A1-sea and dSLC25A4-sesB, affected synapse morphology, neurotransmission, plasticity, and sleep patterns. Our findings indicate that synapses are sensitive to partial loss of function of mitochondrial solute transporters. We propose that mitoproteomes regulate synapse development and function in normal and pathological conditions in a cell-specific manner.SIGNIFICANCE STATEMENT We address the central question of how to comprehensively define molecular mechanisms of the most prevalent and penetrant microdeletion associated with neurodevelopmental disorders, the 22q11.2 microdeletion syndrome. This complex mutation reduces gene dosage of ∼63 genes in humans. We describe a disruption of the mitoproteome in 22q11.2 patients and brains of a 22q11.2 mouse model. In particular, we identify a network of inner mitochondrial membrane transporters as a hub required for synapse function. Our findings suggest that mitochondrial composition and function modulate the risk of neurodevelopmental disorders, such as schizophrenia.

Disrupted-in-schizophrenia-1 protects synaptic plasticity in a transgenic mouse model of Alzheimer's disease as a mitophagy receptor

Mitochondrial dysfunction is an early feature of Alzheimer's disease (AD). Accumulated damaged mitochondria, which are associated with impaired mitophagy, contribute to neurodegeneration in AD. We show levels of Disrupted‐in‐schizophrenia‐1 (DISC1), which is genetically associated with psychiatric disorders and AD, decrease in the brains of AD patients and transgenic model mice and in Aβ‐treated cultured cells. Disrupted‐in‐schizophrenia‐1 contains a canonical LC3‐interacting region (LIR) motif (²¹⁰FSFI²¹³), through which DISC1 directly binds to LC3‐I/II. Overexpression of DISC1 enhances mitophagy through its binding to LC3, whereas knocking‐down of DISC1 blocks Aβ‐induced mitophagy. We further observe overexpression of DISC1, but not its mutant (muFSFI) which abolishes the interaction of DISC1 with LC3, rescues Aβ‐induced mitochondrial dysfunction, loss of spines, suppressed long‐term potentiation (LTP). Overexpression of DISC1 via adeno‐associated virus (serotype 8, AAV8) in the hippocampus of 8‐month‐old APP/PS1 transgenic mice for 4 months rescues cognitive deficits, synaptic loss, and Aβ plaque accumulation, in a way dependent on the interaction of DISC1 with LC3. These results indicate that DISC1 is a novel mitophagy receptor, which protects synaptic plasticity from Aβ accumulation‐induced toxicity through promoting mitophagy.

The Complex Interaction of Mitochondrial Genetics and Mitochondrial Pathways in Psychiatric Disease

While accounting for only 2% of the body's weight, the brain utilizes up to 20% of the body's total energy. Not surprisingly, metabolic dysfunction and energy supply-and-demand mismatch have been implicated in a variety of neurological and psychiatric disorders. Mitochondria are responsible for providing the brain with most of its energetic demands, and the brain uses glucose as its exclusive energy source. Exploring the role of mitochondrial dysfunction in the etiology of psychiatric disease is a promising avenue to investigate further. Genetic analysis of mitochondrial activity is a cornerstone in understanding disease pathogenesis related to metabolic dysfunction. In concert with neuroimaging and pathological study, genetics provides an important bridge between biochemical findings and clinical correlates in psychiatric disease. Mitochondrial genetics has several unique aspects to its analysis, and corresponding special considerations. Here, we review the components of mitochondrial genetic analysis - nuclear DNA, mitochon-drial DNA, mitochondrial pathways, pseudogenes, nuclear-mitochondrial mismatch, and microRNAs - that could contribute to an observable clinical phenotype. Throughout, we highlight psychiatric diseases that can arise due to dysfunction in these processes, with a focus on schizophrenia and bipolar disorder.

DISC1 regulates lactate metabolism in astrocytes: implications for psychiatric disorders

Our knowledge of how genetic risk variants contribute to psychiatric disease is mainly limited to neurons. However, the mechanisms whereby the same genetic risk factors could affect the physiology of glial cells remain poorly understood. We studied the role of a psychiatric genetic risk factor, Disrupted-In-Schizophrenia-1 (DISC1), in metabolic functions of astrocytes. We evaluated the effects of knockdown of mouse endogenous DISC1 (DISC1-KD) and expression of a dominant-negative, C-terminus truncated human DISC1 (DN-DISC1) on the markers of energy metabolism, including glucose uptake and lactate production, in primary astrocytes and in mice with selective expression of DN-DISC1 in astrocytes. We also assessed the effects of lactate treatment on altered affective behaviors and impaired spatial memory in DN-DISC1 mice. Both DISC1-KD and DN-DISC1 comparably decreased mRNA and protein levels of glucose transporter 4 and glucose uptake by primary astrocytes. Decreased glucose uptake was associated with reduced oxidative phosphorylation and glycolysis as well as diminished lactate production in vitro and in vivo. No significant effects of DISC1 manipulations in astrocytes were observed on expression of the subunits of the electron transport chain complexes or mitofilin, a neuronal DISC1 partner. Lactate treatment rescued the abnormal behaviors in DN-DISC1 male and female mice. Our results suggest that DISC1 may be involved in the regulation of lactate production in astrocytes to support neuronal activity and associated behaviors. Abnormal expression of DISC1 in astrocytes and resulting abnormalities in energy supply may be responsible for aspects of mood and cognitive disorders observed in patients with major psychiatric illnesses.

Understanding Miro GTPases: Implications in the Treatment of Neurodegenerative Disorders

The Miro GTPases represent an unusual subgroup of the Ras superfamily and have recently emerged as important mediators of mitochondrial dynamics and for maintaining neuronal health. It is now well-established that these enzymes act as essential components of a Ca²⁺-sensitive motor complex, facilitating the transport of mitochondria along microtubules in several cell types, including dopaminergic neurons. The Miros appear to be critical for both anterograde and retrograde mitochondrial transport in axons and dendrites, both of which are considered essential for neuronal health. Furthermore, the Miros may be significantly involved in the development of several serious pathological processes, including the development of neurodegenerative and psychiatric disorders. In this review, we discuss the molecular structure and known mitochondrial functions of the Miro GTPases in humans and other organisms, in the context of neurodegenerative disease. Finally, we consider the potential human Miros hold as novel therapeutic targets for the treatment of such disease.

HDAC1 links early life stress to schizophrenia-like phenotypes

Schizophrenia is a devastating disease that arises on the background of genetic predisposition and environmental risk factors, such as early life stress (ELS). In this study, we show that ELS-induced schizophrenia-like phenotypes in mice correlate with a widespread increase of histone-deacetylase 1 (Hdac1) expression that is linked to altered DNA methylation. Hdac1 overexpression in neurons of the medial prefrontal cortex, but not in the dorsal or ventral hippocampus, mimics schizophrenia-like phenotypes induced by ELS. Systemic administration of an HDAC inhibitor rescues the detrimental effects of ELS when applied after the manifestation of disease phenotypes. In addition to the hippocampus and prefrontal cortex, mice subjected to ELS exhibit increased Hdac1 expression in blood. Moreover, Hdac1 levels are increased in blood samples from patients with schizophrenia who had encountered ELS, compared with patients without ELS experience. Our data suggest that HDAC1 inhibition should be considered as a therapeutic approach to treat schizophrenia.