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Thabault M, Fernandes-Gomes C, Huot AL, Francheteau M, Balbous-Gautier A, Fernagut PO, Galvan L. Dysfunction of striatal parvalbumin interneurons drives motor stereotypies in Cntnap2-/- mouse model of autism spectrum disorders. PNAS NEXUS 2024; 3:pgae132. [PMID: 38617583 PMCID: PMC11010650 DOI: 10.1093/pnasnexus/pgae132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 03/18/2024] [Indexed: 04/16/2024]
Abstract
The involvement of parvalbumin (PV) interneurons in autism spectrum disorders (ASD) pathophysiology has been widely described without clearly elucidating how their dysfunctions could lead to ASD symptoms. The Cntnap2-/- mice, an ASD mouse model deficient for a major ASD susceptibility gene, display core ASD symptoms including motor stereotypies, which are directly linked to striatal dysfunction. This study reveals that striatal PV interneurons display hyperexcitability and hyperactivity in Cntnap2-/- mice, along with a reduced response in medium spiny neurons. We also provide evidence for a crucial role of striatal PV interneurons in motor stereotypies by demonstrating that their selective inhibition rescued a wild type-like phenotype. Our study identifies how PV interneuron dysfunctions disrupt striatal circuitry and drive the motor stereotypies in ASD.
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Estrada-Sánchez AM, Rebec GV, Galvan L. Editorial: New insight into Huntington's disease: From neuropathology to possible therapeutic targets. Front Neurosci 2023; 17:1138712. [PMID: 36816128 PMCID: PMC9933495 DOI: 10.3389/fnins.2023.1138712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 01/20/2023] [Indexed: 02/05/2023] Open
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Thabault M, Turpin V, Balado É, Fernandes-Gomes C, Huot AL, Cantereau A, Fernagut PO, Jaber M, Galvan L. Age-related behavioural and striatal dysfunctions in Shank3 ΔC/ΔC mouse model of autism spectrum disorder. Eur J Neurosci 2023; 57:607-618. [PMID: 36656446 DOI: 10.1111/ejn.15919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 12/13/2022] [Accepted: 01/13/2023] [Indexed: 01/20/2023]
Abstract
Autism spectrum disorders (ASDs) are defined as a set of neurodevelopmental disorders and a lifelong condition. In mice, most of the studies focused on the developmental aspects of these diseases. In this paper, we examined the evolution of motor stereotypies through adulthood in the Shank3ΔC/ΔC mouse model of ASD, and their underlying striatal alterations, at 10 weeks, 20 weeks, and 40 weeks. We highlighted that motor stereotypies worsened at 40 weeks possibly carried by earlier striatal medium spiny neurons (MSN) alterations in GABAergic transmission and morphology. Moreover, we report that 20 weeks could be a critical time-point in the striatal-related ASD physiopathology, and we suggest that MSN alterations may not be the direct consequence of developmental issues, but rather be a consequence of other impairments occurring earlier.
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Thabault M, Turpin V, Maisterrena A, Jaber M, Egloff M, Galvan L. Cerebellar and Striatal Implications in Autism Spectrum Disorders: From Clinical Observations to Animal Models. Int J Mol Sci 2022; 23:2294. [PMID: 35216408 PMCID: PMC8874522 DOI: 10.3390/ijms23042294] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/07/2022] [Accepted: 02/08/2022] [Indexed: 02/06/2023] Open
Abstract
Autism spectrum disorders (ASD) are complex conditions that stem from a combination of genetic, epigenetic and environmental influences during early pre- and postnatal childhood. The review focuses on the cerebellum and the striatum, two structures involved in motor, sensory, cognitive and social functions altered in ASD. We summarize clinical and fundamental studies highlighting the importance of these two structures in ASD. We further discuss the relation between cellular and molecular alterations with the observed behavior at the social, cognitive, motor and gait levels. Functional correlates regarding neuronal activity are also detailed wherever possible, and sexual dimorphism is explored pointing to the need to apprehend ASD in both sexes, as findings can be dramatically different at both quantitative and qualitative levels. The review focuses also on a set of three recent papers from our laboratory where we explored motor and gait function in various genetic and environmental ASD animal models. We report that motor and gait behaviors can constitute an early and quantitative window to the disease, as they often correlate with the severity of social impairments and loss of cerebellar Purkinje cells. The review ends with suggestions as to the main obstacles that need to be surpassed before an appropriate management of the disease can be proposed.
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Matas E, Maisterrena A, Thabault M, Balado E, Francheteau M, Balbous A, Galvan L, Jaber M. Major motor and gait deficits with sexual dimorphism in a Shank3 mutant mouse model. Mol Autism 2021; 12:2. [PMID: 33468258 PMCID: PMC7814442 DOI: 10.1186/s13229-020-00412-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/29/2020] [Indexed: 11/10/2022] Open
Abstract
Background Contrasting findings were reported in several animal models with a Shank3 mutation used to induce various autism spectrum disorder (ASD) symptoms. Here, we aimed at investigating behavioral, cellular, and molecular consequences of a C-terminal (frameshift in exon 21) deletion in Shank3 protein in mice, a mutation that is also found in clinical conditions and which results in loss of major isoforms of Shank3. A special focus was made on cerebellar related parameters. Methods All three genotypes were analyzed [wild type (WT), heterozygote (Shank3+/ΔC) and homozygote (Shank3 ΔC/ΔC)] and males and females were separated into two distinct groups. Motor and social behavior, gait, Purkinje cells (PC) and glutamatergic protein levels were determined. Behavioral and cellular procedures used here were previously validated using two environmental animal models of ASD. ANOVA and post-hoc analysis were used for statistical analysis. Results Shank3 ΔC/ΔC mice showed significant impairments in social novelty preference, stereotyped behavior and gait. These were accompanied by a decreased number of PC in restricted cerebellar sub-regions and decreased cerebellar expression of mGluR5. Females Shank3 ΔC/ΔC were less affected by the mutation than males. Shank3+/ΔC mice showed impairments only in social novelty preference, grooming, and decreased mGluR5 expression and that were to a much lesser extent than in Shank3 ΔC/ΔC mice. Limitations As Shank3 mutation is a haploinsufficiency, it is of interest to emphasize that Shank3+/ΔC mice showed only mild to no deficiencies compared to Shank3 ΔC/ΔC. Conclusions Our findings indicate that several behavioral, cellular, and molecular parameters are affected in this animal model. The reported deficits are more pronounced in males than in females. Additionally, male Shank3 ΔC/ΔC mice show more pronounced alterations than Shank3+/ΔC. Together with our previous findings in two environmental animal models of ASD, our studies indicate that gait dysfunction constitutes a robust set of motor ASD symptoms that may be considered for implementation in clinical settings as an early and quantitative diagnosis criteria.
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Galvan L, Francelle L, Gaillard MC, de Longprez L, Carrillo-de Sauvage MA, Liot G, Cambon K, Stimmer L, Luccantoni S, Flament J, Valette J, de Chaldée M, Auregan G, Guillermier M, Joséphine C, Petit F, Jan C, Jarrige M, Dufour N, Bonvento G, Humbert S, Saudou F, Hantraye P, Merienne K, Bemelmans AP, Perrier AL, Déglon N, Brouillet E. The striatal kinase DCLK3 produces neuroprotection against mutant huntingtin. Brain 2019. [PMID: 29534157 PMCID: PMC5917821 DOI: 10.1093/brain/awy057] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The neurobiological functions of a number of kinases expressed in the brain are unknown. Here, we report new findings on DCLK3 (doublecortin like kinase 3), which is preferentially expressed in neurons in the striatum and dentate gyrus. Its function has never been investigated. DCLK3 expression is markedly reduced in Huntington's disease. Recent data obtained in studies related to cancer suggest DCLK3 could have an anti-apoptotic effect. Thus, we hypothesized that early loss of DCLK3 in Huntington's disease may render striatal neurons more susceptible to mutant huntingtin (mHtt). We discovered that DCLK3 silencing in the striatum of mice exacerbated the toxicity of an N-terminal fragment of mHtt. Conversely, overexpression of DCLK3 reduced neurodegeneration produced by mHtt. DCLK3 also produced beneficial effects on motor symptoms in a knock-in mouse model of Huntington's disease. Using different mutants of DCLK3, we found that the kinase activity of the protein plays a key role in neuroprotection. To investigate the potential mechanisms underlying DCLK3 effects, we studied the transcriptional changes produced by the kinase domain in human striatal neurons in culture. Results show that DCLK3 regulates in a kinase-dependent manner the expression of many genes involved in transcription regulation and nucleosome/chromatin remodelling. Consistent with this, histological evaluation showed DCLK3 is present in the nucleus of striatal neurons and, protein-protein interaction experiments suggested that the kinase domain interacts with zinc finger proteins, including the transcriptional activator adaptor TADA3, a core component of the Spt-ada-Gcn5 acetyltransferase (SAGA) complex which links histone acetylation to the transcription machinery. Our novel findings suggest that the presence of DCLK3 in striatal neurons may play a key role in transcription regulation and chromatin remodelling in these brain cells, and show that reduced expression of the kinase in Huntington's disease could render the striatum highly vulnerable to neurodegeneration.
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Holley SM, Galvan L, Kamdjou T, Dong A, Levine MS, Cepeda C. Major Contribution of Somatostatin-Expressing Interneurons and Cannabinoid Receptors to Increased GABA Synaptic Activity in the Striatum of Huntington's Disease Mice. Front Synaptic Neurosci 2019; 11:14. [PMID: 31139071 PMCID: PMC6527892 DOI: 10.3389/fnsyn.2019.00014] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Accepted: 04/23/2019] [Indexed: 01/01/2023] Open
Abstract
Huntington’s disease (HD) is a heritable neurological disorder that affects cognitive and motor performance in patients carrying the mutated huntingtin (HTT) gene. In mouse models of HD, previous reports showed a significant increase in spontaneous GABAA receptor-mediated synaptic activity in striatal spiny projection neurons (SPNs). In this study, using optogenetics and slice electrophysiology, we examined the contribution of γ-aminobutyric acid (GABA)-ergic parvalbumin (PV)- and somatostatin (SOM)-expressing interneurons to the increase in GABA neurotransmission using the Q175 (heterozygote) mouse model of HD. Patch clamp recordings in voltage-clamp mode were performed on SPNs from brain slices of presymptomatic (2 months) and symptomatic (8 and 12 months) Q175 mice and wildtype (WT) littermates. While inhibitory postsynaptic currents (IPSCs) evoked in SPNs following optical activation of PV- and SOM-expressing interneurons differed in amplitude, no genotype-dependent differences were observed at all ages from both interneuron types; however, responses evoked by either type were found to have faster kinetics in symptomatic mice. Since SOM-expressing interneurons are constitutively active in striatal brain slices, we then examined the effects of acutely silencing these neurons in symptomatic mice with enhanced Natronomonas pharaonis halorhodopsin (eNpHR). Optically silencing SOM-expressing interneurons resulted in a greater decrease in the frequency of spontaneous IPSCs (sIPSCs) in a subset of SPNs from Q175 mice compared to WTs, suggesting that SOM-expressing interneurons are the main contributors to the overall increased GABA synaptic activity in HD SPNs. Additionally, the effects of activating GABAB and cannabinoid (CB1) receptors were investigated to determine whether these receptors were involved in modulating interneuron-specific GABA synaptic transmission and if this modulation differed in HD mice. When selectively activating PV- and SOM-expressing interneurons in the presence of the CB1 receptor agonist WIN-55,212, the magnitudes of the evoked IPSCs in SPNs decreased for both interneuron types although this change was less prominent in symptomatic Q175 SPNs during SOM-expressing interneuron activation. Overall, these findings show that dysfunction of SOM-expressing interneurons contributes to the increased GABA synaptic activity found in HD mouse models and that dysregulation of the endocannabinoid system may contribute to this effect.
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Holley SM, Galvan L, Kamdjou T, Cepeda C, Levine MS. Striatal GABAergic interneuron dysfunction in the Q175 mouse model of Huntington's disease. Eur J Neurosci 2018; 49:79-93. [PMID: 30472747 DOI: 10.1111/ejn.14283] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 11/01/2018] [Accepted: 11/13/2018] [Indexed: 01/01/2023]
Abstract
The pathological hallmark of Huntington's disease (HD) is the massive loss of striatal and cortical neurons. Until recently, it was believed that striatal interneurons were spared from degeneration. This view has changed after the demonstration that parvalbumin (PV)-expressing interneurons also are vulnerable in humans. Here we compared morphological and functional changes of striatal fast-spiking interneurons (FSIs) and low-threshold spiking (LTS) interneurons in the Q175 mouse model of HD at presymptomatic (2 months) and symptomatic (12 months) stages of the disease. Electrophysiological intrinsic and synaptic properties of FSIs were significantly altered in symptomatic mice compared to wild-type (WT) littermates. Overall, FSIs became more excitable with disease progression. Sholl analysis also revealed a significant loss of dendritic complexity and excitatory synaptic inputs. The basic membrane and synaptic properties of LTS interneurons were similar in Q175 and WT mice regardless of disease stage. The resilience of LTS interneurons could be related to their sparsity of excitatory synaptic inputs compared with FSIs. However, in symptomatic mice, a subpopulation of LTS interneurons displayed an increase in action potential firing within oscillating bursts. Thus, we conclude that while both FSI and LTS interneurons demonstrate increases in excitability, the HD mutation differentially affects their membrane and synaptic properties as well as their ability to respond to compensatory challenges presented during the late stage of the disease. Alterations in GABAergic interneuron intrinsic activity and responsiveness to incoming signals may significantly affect SPN output thus contributing to abnormal motor movements in patients afflicted with HD.
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Galvan L, André VM, Wang EA, Cepeda C, Levine MS. Functional Differences Between Direct and Indirect Striatal Output Pathways in Huntington's Disease. J Huntingtons Dis 2016; 1:17-25. [PMID: 25063187 DOI: 10.3233/jhd-2012-120009] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
There is morphological evidence for differential alterations in striatal medium-sized spiny neurons (MSNs) giving rise to the direct and indirect output pathways in Huntington's disease (HD). MSNs of the indirect pathway appear to be particularly vulnerable and markers for these neurons are lost early in postmortem brains and in genetic mouse models. In contrast, MSNs of the direct pathway appear to be relatively spared in the early stages. Because of the great morphological and electrophysiological similarities between MSNs of these pathways, until recently it was difficult to tease apart their functional alterations in HD models. The recent use of the enhanced green fluorescent protein gene as a reporter to identify dopamine D1 (direct pathway) and D2 (indirect pathway) receptor-expressing MSNs has made it possible to examine synaptic function in each pathway. The outcomes of such studies demonstrate significant time-dependent changes in the balance of excitatory and inhibitory inputs to both direct and indirect pathway MSNs in HD and emphasize early increases in both excitatory and inhibitory inputs to direct pathway MSNs. There also is a strong influence of alterations in dopamine modulation that possibly cause some of the changes in excitatory and inhibitory synaptic transmission in the HD models. These changes will markedly alter the output structures, the GPi and the SNr. In the future, the use of combined optogenetics with identified neurons in each pathway will help unravel the next set of questions about how the output nuclei are affected in HD.
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Boussicault L, Alves S, Lamazière A, Planques A, Heck N, Moumné L, Despres G, Bolte S, Hu A, Pagès C, Galvan L, Piguet F, Aubourg P, Cartier N, Caboche J, Betuing S. CYP46A1, the rate-limiting enzyme for cholesterol degradation, is neuroprotective in Huntington's disease. Brain 2016; 139:953-70. [PMID: 26912634 PMCID: PMC4766376 DOI: 10.1093/brain/awv384] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 11/04/2015] [Indexed: 11/22/2022] Open
Abstract
Huntington’s disease is an autosomal dominant neurodegenerative disease caused by abnormal polyglutamine expansion in huntingtin (Exp-HTT) leading to degeneration of striatal neurons. Altered brain cholesterol homeostasis has been implicated in Huntington’s disease, with increased accumulation of cholesterol in striatal neurons yet reduced levels of cholesterol metabolic precursors. To elucidate these two seemingly opposing dysregulations, we investigated the expression of cholesterol 24-hydroxylase (CYP46A1), the neuronal-specific and rate-limiting enzyme for cholesterol conversion to 24S-hydroxycholesterol (24S-OHC). CYP46A1 protein levels were decreased in the putamen, but not cerebral cortex samples, of post-mortem Huntington’s disease patients when compared to controls.
Cyp46A1
mRNA and CYP46A1 protein levels were also decreased in the striatum of the R6/2 Huntington’s disease mouse model and in ST
hdh
Q111 cell lines.
In vivo
, in a wild-type context, knocking down CYP46A1 expression in the striatum, via an adeno-associated virus-mediated delivery of selective shCYP46A1, reproduced the Huntington’s disease phenotype, with spontaneous striatal neuron degeneration and motor deficits, as assessed by rotarod.
In vitro
, CYP46A1 restoration protected ST
hdh
Q111 and Exp-HTT-expressing striatal neurons in culture from cell death. In the R6/2 Huntington’s disease mouse model, adeno-associated virus-mediated delivery of CYP46A1 into the striatum decreased neuronal atrophy, decreased the number, intensity level and size of Exp-HTT aggregates and improved motor deficits, as assessed by rotarod and clasping behavioural tests. Adeno-associated virus-CYP46A1 infection in R6/2 mice also restored levels of cholesterol and lanosterol and increased levels of desmosterol.
In vitro
, lanosterol and desmosterol were found to protect striatal neurons expressing Exp-HTT from death. We conclude that restoring CYP46A1 activity in the striatum promises a new therapeutic approach in Huntington’s disease.
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Berg JM, Lee C, Chen L, Galvan L, Cepeda C, Chen JY, Peñagarikano O, Stein JL, Li A, Oguro-Ando A, Miller JA, Vashisht AA, Starks ME, Kite EP, Tam E, Gdalyahu A, Al-Sharif NB, Burkett ZD, White SA, Fears SC, Levine MS, Wohlschlegel JA, Geschwind DH. JAKMIP1, a Novel Regulator of Neuronal Translation, Modulates Synaptic Function and Autistic-like Behaviors in Mouse. Neuron 2015; 88:1173-1191. [PMID: 26627310 DOI: 10.1016/j.neuron.2015.10.031] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 09/02/2015] [Accepted: 10/15/2015] [Indexed: 11/18/2022]
Abstract
Autism spectrum disorder (ASD) is a heritable, common neurodevelopmental disorder with diverse genetic causes. Several studies have implicated protein synthesis as one among several of its potential convergent mechanisms. We originally identified Janus kinase and microtubule-interacting protein 1 (JAKMIP1) as differentially expressed in patients with distinct syndromic forms of ASD, fragile X syndrome, and 15q duplication syndrome. Here, we provide multiple lines of evidence that JAKMIP1 is a component of polyribosomes and an RNP translational regulatory complex that includes fragile X mental retardation protein, DEAD box helicase 5, and the poly(A) binding protein cytoplasmic 1. JAKMIP1 loss dysregulates neuronal translation during synaptic development, affecting glutamatergic NMDAR signaling, and results in social deficits, stereotyped activity, abnormal postnatal vocalizations, and other autistic-like behaviors in the mouse. These findings define an important and novel role for JAKMIP1 in neural development and further highlight pathways regulating mRNA translation during synaptogenesis in the genesis of neurodevelopmental disorders.
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Francelle L, Galvan L, Gaillard MC, Guillermier M, Houitte D, Bonvento G, Petit F, Jan C, Dufour N, Hantraye P, Elalouf JM, De Chaldée M, Déglon N, Brouillet E. Loss of the thyroid hormone-binding protein Crym renders striatal neurons more vulnerable to mutant huntingtin in Huntington's disease. Hum Mol Genet 2014; 24:1563-73. [PMID: 25398949 PMCID: PMC4381754 DOI: 10.1093/hmg/ddu571] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The mechanisms underlying preferential atrophy of the striatum in Huntington's disease (HD) are unknown. One hypothesis is that a set of gene products preferentially expressed in the striatum could determine the particular vulnerability of this brain region to mutant huntingtin (mHtt). Here, we studied the striatal protein µ-crystallin (Crym). Crym is the NADPH-dependent p38 cytosolic T3-binding protein (p38CTBP), a key regulator of thyroid hormone (TH) T3 (3,5,3'-triiodo-l-thyronine) transportation. It has been also recently identified as the enzyme that reduces the sulfur-containing cyclic ketimines, which are potential neurotransmitters. Here, we confirm the preferential expression of the Crym protein in the rodent and macaque striatum. Crym expression was found to be higher in the macaque caudate than in the putamen. Expression of Crym was reduced in the BACHD and Knock-in 140CAG mouse models of HD before onset of striatal atrophy. We show that overexpression of Crym in striatal medium-size spiny neurons using a lentiviral-based strategy in mice is neuroprotective against the neurotoxicity of an N-terminal fragment of mHtt in vivo. Thus, reduction of Crym expression in HD could render striatal neurons more susceptible to mHtt suggesting that Crym may be a key determinant of the vulnerability of the striatum. In addition our work points to Crym as a potential molecular link between striatal degeneration and the THs deregulation reported in HD patients.
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Francelle L, Galvan L, Brouillet E. Possible involvement of self-defense mechanisms in the preferential vulnerability of the striatum in Huntington's disease. Front Cell Neurosci 2014; 8:295. [PMID: 25309327 PMCID: PMC4176035 DOI: 10.3389/fncel.2014.00295] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 09/03/2014] [Indexed: 01/01/2023] Open
Abstract
HD is caused by a mutation in the huntingtin gene that consists in a CAG repeat expansion translated into an abnormal poly-glutamine (polyQ) tract in the huntingtin (Htt) protein. The most striking neuropathological finding in HD is the atrophy of the striatum. The regional expression of mutant Htt (mHtt) is ubiquitous in the brain and cannot explain by itself the preferential vulnerability of the striatum in HD. mHtt has been shown to produce an early defect in transcription, through direct alteration of the function of key regulators of transcription and in addition, more indirectly, as a result of compensatory responses to cellular stress. In this review, we focus on gene products that are preferentially expressed in the striatum and have down- or up-regulated expression in HD and, as such, may play a crucial role in the susceptibility of the striatum to mHtt. Many of these striatal gene products are for a vast majority down-regulated and more rarely increased in HD. Recent research shows that some of these striatal markers have a pro-survival/neuroprotective role in neurons (e.g., MSK1, A2A, and CB1 receptors) whereas others enhance the susceptibility of striatal neurons to mHtt (e.g., Rhes, RGS2, D2 receptors). The down-regulation of these latter proteins may be considered as a potential self-defense mechanism to slow degeneration. For a majority of the striatal gene products that have been identified so far, their function in the striatum is unknown and their modifying effects on mHtt toxicity remain to be experimentally addressed. Focusing on these striatal markers may contribute to a better understanding of HD pathogenesis, and possibly the identification of novel therapeutic targets.
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Damiano M, Diguet E, Malgorn C, D'Aurelio M, Galvan L, Petit F, Benhaim L, Guillermier M, Houitte D, Dufour N, Hantraye P, Canals JM, Alberch J, Delzescaux T, Déglon N, Beal MF, Brouillet E. A role of mitochondrial complex II defects in genetic models of Huntington's disease expressing N-terminal fragments of mutant huntingtin. Hum Mol Genet 2013; 22:3869-82. [PMID: 23720495 PMCID: PMC3766181 DOI: 10.1093/hmg/ddt242] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by an abnormal expansion of a CAG repeat encoding a polyglutamine tract in the huntingtin (Htt) protein. The mutation leads to neuronal death through mechanisms which are still unknown. One hypothesis is that mitochondrial defects may play a key role. In support of this, the activity of mitochondrial complex II (C-II) is preferentially reduced in the striatum of HD patients. Here, we studied C-II expression in different genetic models of HD expressing N-terminal fragments of mutant Htt (mHtt). Western blot analysis showed that the expression of the 30 kDa Iron–Sulfur (Ip) subunit of C-II was significantly reduced in the striatum of the R6/1 transgenic mice, while the levels of the FAD containing catalytic 70 kDa subunit (Fp) were not significantly changed. Blue native gel analysis showed that the assembly of C-II in mitochondria was altered early in N171-82Q transgenic mice. Early loco-regional reduction in C-II activity and Ip protein expression was also demonstrated in a rat model of HD using intrastriatal injection of lentiviral vectors encoding mHtt. Infection of the rat striatum with a lentiviral vector coding the C-II Ip or Fp subunits induced a significant overexpression of these proteins that led to significant neuroprotection of striatal neurons against mHtt neurotoxicity. These results obtained in vivo support the hypothesis that structural and functional alterations of C-II induced by mHtt may play a critical role in the degeneration of striatal neurons in HD and that mitochondrial-targeted therapies may be useful in its treatment.
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Chen JY, Wang E, Galvan L, Huynh M, Joshi P, Cepeda C, Levine MS. Effects of the Pimelic Diphenylamide Histone Deacetylase Inhibitor HDACi 4b on the R6/2 and N171-82Q Mouse Models of Huntington's Disease. PLOS CURRENTS 2013; 5. [PMID: 23437422 PMCID: PMC3574864 DOI: 10.1371/currents.hd.ec3547da1c2a520ba959ee7bf8bdd202] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This report represents a detailed description of experiments designed to replicate and extend the findings of a published study on the effects of treating the R6/2 Huntington’s disease (HD) mouse model with ~300 CAG repeats using the pimelic diphenylamide histone deacetylase (HDAC) inhibitor, HDACi 4b (Thomas et al., 2008). In addition to testing the R6/2 mice, similar experiments examined the effects of the drug on a second transgenic HD mouse model, the N171-82Q mice. As in the original study, the drug was delivered in the drinking water. In the present study we tested larger groups of mice than in the original study. The results indicated that we were unable to replicate the significant behavioral effects of oral HDACi 4b treatment in the R6/2 mice. There were however, non-significant trends for the treated R6/2 mice to be less affected on some of the measures and there were instances of phenotype progression being delayed in these treated mice. In contrast, we did replicate the protection from striatal atrophy in the R6/2 mice. We also did not observe any beneficial effects of HDACi 4b treatment in the N171-82Q mice. Although the behavioral procedures were replicated and an automated activity assessment was added, there were several unexpected complications in terms of solubility of the drug, CAG repeat length differences and gender differences in progression of the phenotype that could have affected outcomes. Clearly more studies will have to be performed using other methods of delivery as well as assessing effects in more slowly progressing HD models to better evaluate the effects of this HDAC inhibitor.
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Olmo M, Galvan L, Capdevila J, Serna C, Mangues I, Schoenenberger JA. Management by objectives and its impact on specialist prescription quality at discharge and in external consultations. FARMACIA HOSPITALARIA 2011; 35:58-63. [PMID: 20678949 DOI: 10.1016/j.farma.2010.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Accepted: 04/26/2010] [Indexed: 10/19/2022] Open
Abstract
OBJECTIVE To verify that implementing a policy of management by objectives, based on collaboration between hospital pharmacy, primary care and specialised medical managers, improves prescription quality indicators in specialised care and reduces unwanted "induced" prescriptions (i.e. those issued by specialists, hospital doctors or the patients themselves) in primary care. METHOD A four year quasi-experimental controlled intervention study on prescription at discharge and in outpatient hospital consultations was conducted. In hospital A, a quality cycle was applied: assessment, identifying improvement opportunities, implementing corrective actions and re-assessment. However, it was not applied in control hospital B. The indicators chosen were the percentage of generic medicines prescribed, the percentage of prescriptions for new therapies with no added value and the percentage of prescriptions for ACE inhibitors recommended. RESULTS In hospital A, an increase in indicators 1 and 3 has been observed, both being statistically significant, between the last year of intervention and the year previous to intervention. Hospital A managed to reduce indicator 2 to 4.5%, while this indicator increased in hospital B to 8.8%. Furthermore, a statistically significant difference in indicators between the two hospitals has been registered. CONCLUSION Pay-for-Performance programs in prescription practices of hospital physicians are effective actions to improve quality indicators of medication use.
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Damiano M, Galvan L, Déglon N, Brouillet E. Mitochondria in Huntington's disease. Biochim Biophys Acta Mol Basis Dis 2010; 1802:52-61. [DOI: 10.1016/j.bbadis.2009.07.012] [Citation(s) in RCA: 201] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Revised: 07/31/2009] [Accepted: 07/31/2009] [Indexed: 11/16/2022]
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Galvan L, Brouillet E. Rhes, a protein with selective expression in the striatum, plays a major role in Huntington’s disease pathogenesis. FUTURE NEUROLOGY 2009. [DOI: 10.2217/fnl.09.46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Evaluation of: Subramaniam S, Sixt KM, Barrow R, Snyder SH: Rhes, a striatal specific protein, mediates mutant-huntingtin cytotoxicity. Science 324, 1327–1330 (2009). Huntington’s disease (HD) is an autosomal dominant neurodegenerative disorder characterized by choreiform movements, cognitive deficits and psychiatric disturbances. The disease is caused by an abnormal expansion of a CAG repeat located in exon 1 of the gene encoding the huntingtin protein (Htt). The genetic defect encodes a polyglutamine tract in the N-terminal part of Htt that confers a toxic function to the protein. The most striking neuropathological hallmark in HD patients is the selective atrophy of the striatum. The mechanisms underlying the particular vulnerability of the striatum are unknown. Subramaniam and collaborators demonstrate that the cytotoxicity of mutant Htt is greatly enhanced in the presence of the small GTPase, Rhes, a protein of unclear function that has a preferential expression in the striatum. The study demonstrates that Rhes is an E3 ligase, interacts with mutant Htt and modifies it through SUMOylation, a post-transcriptional process that consists of the addition of the protein SUMO1 to mutant Htt. By contrast, the GTPase activity of Rhes does not seem to be involved in the toxicity of mutant Htt. The Rhes-mediated sumoylation of mutant Htt eventually leads to reduced levels of neuroprotective insoluble aggregates, and increased levels of the toxic soluble form of mutant Htt. These completely novel results shed new light on HD pathogenesis. The selective expression of Rhes in the striatum and its role in mutant Htt toxicity could explain why the striatum is so vulnerable in HD. This work may lead to new therapeutic strategies targeting Rhes.
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Espallergues J, Galvan L, Sabatier F, Rana-Poussine V, Maurice T, Chatonnet A. Behavioral phenotyping of heterozygous acetylcholinesterase knockout (AChE+/-) mice showed no memory enhancement but hyposensitivity to amnesic drugs. Behav Brain Res 2009; 206:263-73. [PMID: 19766675 DOI: 10.1016/j.bbr.2009.09.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Revised: 09/09/2009] [Accepted: 09/14/2009] [Indexed: 12/24/2022]
Abstract
Decrease in the expression or activity of acetylcholinesterase (AChE) enzymatic activity results in increased cholinergic tonus in the brain and periphery, with concomitant regulations of nicotinic and muscarinic receptors expression. We generated AChE knockout mice and characterized the behavioral phenotype of heterozygous animals, focusing on learning and memory functions. Male and female, AChE+/- and AChE+/+ littermate controls (129 sv strain) were tested at 5-9 weeks of age. AChE activity was significantly decreased in the hippocampus and cortex of AChE+/- mice, but butyrylcholinesterase activity was preserved. AChE+/- mice failed to show any difference in terms of locomotion, exploration and anxiety parameters in the open-field test. Animals were then tested for place learning in the water-maze. They were trained using a 'sustained acquisition' protocol (3 swim trials per day) or a 'mild acquisition' protocol (2 swim trials per day) to locate an invisible platform in fixed position (reference memory procedure). Then, during 3 days, they were trained to locate the platform in a variable position (working memory procedure). Learning profiles and probe test performances were similar for AChE+/- and AChE+/+ mice. Mice were then treated with the muscarinic receptor antagonist scopolamine (0.5, 5 mg/kg) 20 min before each training session. Scopolamine impaired learning at both doses in AChE+/+ mice, but only at the highest dose in AChE+/- mice. Moreover, the intracerebroventricular injection of amyloid-beta25-35 peptide, 9 nmol, 7 days before water-maze acquisition, failed to induce learning deficits in AChE+/- mice, but impaired learning in AChE+/+ controls. The peptide failed to be toxic in forebrain structures of AChE+/- mice, since an increase in lipid peroxidation levels was measured in the hippocampus of AChE+/+ but not AChE+/- mice. We conclude that the increase in cholinergic tonus observed in AChE+/- mice did not result in increased memory functions but allowed a significant prevention of the deleterious effects of muscarinic blockade or amyloid toxicity.
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Abstract
Heparin, an anticoagulant that is widely used for cardiac patients, has been studied to determine its effects on wound healing. The role of heparin in wound healing has been demonstrated in both in vitro and in vivo studies. In cell culture studies, heparin and growth factors are associated with rapid and effective endothelial cell repair. In clinical studies, patients with burns and those with diabetic foot ulcers showed an increase in capillary circulation and decreased healing time. In contrast, heparin may not be beneficial in populations with ischemia, malnourishment, and vascular problems, although research in these populations is limited. Nevertheless, heparin continues to have therapeutic advantages for wound healing in carefully selected patients.
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Galvan L, Evans JE, Huang CH, Prestayko A, Wu B, Crooke ST. Inhibition of PM-2 DNA degradation by a human serum protein. Cancer Res 1982; 42:1555-61. [PMID: 6174227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A unique DNA-binding protein was detected that inhibited DNA degradation induced by bleomycin and was decreased in sera of cancer patients. The protein from normal human serum was purified to homogeneity by ammonium sulfate precipitation and DEAE-cellulose and DNA-cellulose column chromatography. Two-dimensional isoelectric focusing gel electrophoresis revealed a single protein spot with a molecular weight of 64,000 and a pI at pH 5.9. The NH2 terminus was lysine, and the ratio of acidic to basic residues was 1.2. DNA binding was demonstrated by column chromatography, agarose gel electrophoresis, fluorescence quenching, and circular dichroism. The inhibitory activity was abolished by treatment with Pronase but not by RNase or DNase I. FeCl2 caused a partial loss of inhibitory activity. The inhibition of DNA degradation was more effective for breakage induced by bleomycin than neocarzinostatin, macromomycin, or DNase I. Evidence from DNA-binding studies suggests the inhibition is due to binding of the protein to sites on DNA preferred by bleomycin. Thus, the protein could be useful for studies on the mechanism of action of bleomycin and other antitumor agents, the cytotoxic effects of which are due primarily to damage of cellular DNA. The protein was decreased significantly in sera of cancer patients, and its potential use as a diagnostic tool for neoplasias is being investigated further.
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Galvan L, Evans JE, Comis RL, Gottlieb A, Gyorkey F, Lane M, Prestayko AW, Crooke ST. Detection of a serum DNA-binding protein associated with cancer. Cancer Res 1982; 42:1562-6. [PMID: 6174228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
An accompanying report describes the purification and partial characterization of a unique DNA-binding protein (Mr 64,000; pI 5.9) that is present in human sera. This report gives the results of assays of sera from patients for the bleomycin inhibitor protein (BIP) using the Pseudomonas bacteriophage covalently closed circular DNA fluorescence technique standardized for DNA breakage induced by bleomycin. The results of the BIP assays were expressed by values of specific activity of inhibition. One arbitrary unit of inhibitory activity was defined as equivalent to the amount of serum protein required to cause 50% inhibition of DNA degradation using standard conditions of the DNA breakage assay. The mean values of specific activity of inhibition (SAI) for groups of healthy individuals (n = 26), patients with nonmalignant diseases (n = 33), and patients with malignant diseases (n = 83) were 12.60 +/- 4.69 (S.E.), 12.53 +/- 3.17, and 2.40 +/- 0.84 units/mg, respectively. Mean SAI values for patients with cancers of various types were: solid tumors (n = 46), 2.44 +/- 0.86; leukemias (n = 24), 2.59 +/- 0.96; and lymphomas (n = 18), 2.07 +/- 0.64. The decrease in BIP activity was not correlated with sex, age, or prior chemotherapy. Mean SAI values of male (n = 29) and female (n = 59) patients with cancer were 2.61 +/- 0.87 and 2.30 +/- 0.83 units/mg, respectively. Mean SAI values for different age groups were: 0 to 40 years (n = 21), 2.05 +/- 0.68 units/mg; 41 to 70 years (n = 56), 2.59 +/- 0.68 units/mg; and greater than 70 years (n = 11), 2.12 +/- 0.67 units/mg. Cancer patients with and without prior chemotherapy had mean SAI values of 2.97 +/- 0.85 (n = 23) and 2.20 +/- 0.86 units/mg (n = 65), respectively. Linear regression analysis comparing SAI values and serum protein levels showed no correlation (r = 0.21). These results suggest the decrease of the BIP is associated with malignant disease. Additional controlled studies are required before the significance of this association can be adequately assessed.
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Galvan L, Huang CH, Prestayko AW, Stout JT, Evans JE, Crooke ST. Inhibition of bleomycin-induced DNA breakage by superoxide dismutase. Cancer Res 1981; 41:5103-6. [PMID: 6171347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Inhibition of bleomycin (BLM)-induced DNA breakage by superoxide dismutase (SOD) has been reported and presumed to be due to its removal of the superoxide free radicals generated by BLM in the presence of iron(II). We have studied the possibility that the inhibitory effect might result from DNA-binding of SOD. The effect of copper-zinc SOD on BLM-induced DNA degradation was investigated using the PM-2 DNA fluorescence technique. PM-2 DNA was incubated with BLM in the presence or absence of native and heat-inactivated copper-zinc SOD as determined by the epinephrine autoxidation method. The concentrations of SOD required to inhibit 50% PM-2 DNA degradation for the native and the inactivated SOD were 100 and 120 microgram/ml, respectively. Analysis of the reaction mixture by agarose gel electrophoresis confirmed the absence of DNA degradation by BLM in the presence of either form of SOD. PM-2 DNA was shown to bind native or inactivated SOD by Sephadex G-100 column chromatography, fluorescence-quenching studies, and agarose gel electrophoresis. Thus, these results indicate that SOD is able to bind to PM-2 DNA and inhibit BLM-induced degradation independently of its free radical-scavenging activity. The inhibitor was more effective against BLM than other compounds which degrade PM-2 DNA. This suggests that SOD may bind to BLM-binding and/or BLM degradation sites in PM-2 DNA, and the observed inhibition is unrelated to its effects on free radicals.
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Huang CH, Galvan L, Crooke ST. Interactions of bleomycin analogues with deoxyribonucleic acid and metal ions studied by fluorescence quenching. Biochemistry 1980; 19:1761-7. [PMID: 6155142 DOI: 10.1021/bi00550a006] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Galvan L, Strong JE, Crooke ST. Use of PM-2 DNA degradation as a pharmacokinetic assay for bleomycin. Cancer Res 1979; 39:3948-51. [PMID: 89893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The PM-2 DNA fluorescence assay has been shown to be a rapid, sensitive, and reproducible assay for bleomycin biochemical activity. The assay can detect bleomycin in human serum in the nmol range. The method measures DNA degradative activity of bleomycin and could be used to determine activity of bleomycin analogs and metabolites. The usefulness of the assay to perform bleomycin pharmacokinetic studies in cancer patients has been demonstrated. Linear regression analyses of parallel bleomycin assays with the radioimmunoassay gave a coefficient of correlation of 0.98 to 0.78 with trichloroacetic acid-treated serum. These results indicate excellent agreement between the two assays.
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