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ABSTRACT: Lowering mutant Huntingtin is a consensus therapeutic strategy for Huntington's disease. In this issue of Neuron, Kordasiewicz et al. (2012) show the benefit of transient antisense oligonucleotide (ASO) therapy to degrade Huntingtin mRNA and elicit sustained therapeutic benefit in HD mice.
Neuron 06/2012; 74(6):964-6. · 14.74 Impact Factor
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Jifang Tao,
Hao Wu,
Quan Lin,
Weizheng Wei, Xiao-Hong Lu,
Jeffrey P Cantle,
Yan Ao,
Richard W Olsen,
X William Yang,
Istvan Mody,
Michael V Sofroniew,
Yi E Sun
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ABSTRACT: The endoribonuclease, Dicer, is indispensable for generating the majority of mature microRNAs (miRNAs), which are posttranscriptional regulators of gene expression involved in a wide range of developmental and pathological processes in the mammalian CNS. Although functions of Dicer-dependent miRNA pathways in neurons and oligodendrocytes have been extensively investigated, little is known about the role of Dicer in astrocytes. Here, we report the effect of Cre-loxP-mediated conditional deletion of Dicer selectively from postnatal astroglia on brain development. Dicer-deficient mice exhibited normal motor development and neurological morphology before postnatal week 5. Thereafter, mutant mice invariably developed a rapidly fulminant neurological decline characterized by ataxia, severe progressive cerebellar degeneration, seizures, uncontrollable movements, and premature death by postnatal week 9-10. Integrated transcription profiling, histological, and functional analyses of cerebella showed that deletion of Dicer in cerebellar astrocytes altered the transcriptome of astrocytes to be more similar to an immature or reactive-like state before the onset of neurological symptoms or morphological changes. As a result, critical and mature astrocytic functions including glutamate uptake and antioxidant pathways were substantially impaired, leading to massive apoptosis of cerebellar granule cells and degeneration of Purkinje cells. Collectively, our study demonstrates the critical involvement of Dicer in normal astrocyte maturation and maintenance. Our findings also reveal non-cell-autonomous roles of astrocytic Dicer-dependent pathways in regulating proper neuronal functions and implicate that loss of or dysregulation of astrocytic Dicer-dependent pathways may be involved in neurodegeneration and other neurological disorders.
Journal of Neuroscience 06/2011; 31(22):8306-19. · 7.11 Impact Factor
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ABSTRACT: This article reviews recent literature describing novel mouse genetic models of obsessive-compulsive disorder-like behaviors and neurobiological insights gained from analyses of such models.
Obsessive-compulsive disorder is a common neuropsychiatric disorder characterized by recurrent intrusive thoughts (obsessions) and ritualistic (compulsive) behaviors. Although the cause of this disorder remains unclear, recent studies of novel mouse genetic models with excessive grooming behaviors have begun to shed light on the molecular and cellular mechanisms underlying the pathogenesis of 'obsessive-compulsive disorder-like' behaviors. Genetic deletion of three genes in mice, Hoxb8, Sapap3, and Slitrk5, leads to pathological behaviors including adult-onset excessive grooming with mild-to-severe hair loss and self-injury. In two of the models, the Sapap3-deficient and the Slitrk5-deficient mice, the abnormal grooming behaviors are associated with enhanced anxiety and these pathological behaviors can be curtailed with subchronic administration of a selective serotonin reuptake inhibitor, suggesting the predictive validity of such models. Molecular, pathophysiological, and genetic analyses of these models reveal several insights on the etiological basis of abnormal behaviors in these mice, including abnormal cortico-striatal synapse formation and function in Sapap3 mice, impaired development and function of bone marrow-derived microglia in Hoxb8 mice, and abnormal striatal neuronal differentiation and neurotransmission in Slitrk5 mice.
Novel animal models provide powerful tools to investigate the molecular, cellular, and circuitry mechanisms of obsessive-compulsive disorder-like behaviors. Detailed analyses of these models may provide candidate molecules and mechanisms for the investigation of cause and therapy of obsessive-compulsive disorder.
Current opinion in neurology 04/2011; 24(2):114-8. · 5.43 Impact Factor
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Xiao-Hong Lu,
Sheila M Fleming,
Bernhard Meurers,
Larry C Ackerson,
Farzad Mortazavi,
Victor Lo,
Daniela Hernandez,
David Sulzer,
George R Jackson,
Nigel T Maidment,
Marie-Francoise Chesselet,
X William Yang
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ABSTRACT: Recessive mutations in parkin are the most common cause of familial early-onset Parkinson's disease (PD). Recent studies suggest that certain parkin mutants may exert dominant toxic effects to cultured cells and such dominant toxicity can lead to progressive dopaminergic (DA) neuron degeneration in Drosophila. To explore whether mutant parkin could exert similar pathogenic effects to mammalian DA neurons in vivo, we developed a BAC (bacterial artificial chromosome) transgenic mouse model expressing a C-terminal truncated human mutant parkin (Parkin-Q311X) in DA neurons driven by a dopamine transporter promoter. Parkin-Q311X mice exhibit multiple late-onset and progressive hypokinetic motor deficits. Stereological analyses reveal that the mutant mice develop age-dependent DA neuron degeneration in substantia nigra accompanied by a significant loss of DA neuron terminals in the striatum. Neurochemical analyses reveal a significant reduction of the striatal dopamine level in mutant mice, which is significantly correlated with their hypokinetic motor deficits. Finally, mutant Parkin-Q311X mice, but not wild-type controls, exhibit age-dependent accumulation of proteinase K-resistant endogenous alpha-synuclein in substantia nigra and colocalized with 3-nitrotyrosine, a marker for oxidative protein damage. Hence, our study provides the first mammalian genetic evidence that dominant toxicity of a parkin mutant is sufficient to elicit age-dependent hypokinetic motor deficits and DA neuron loss in vivo, and uncovers a causal relationship between dominant parkin toxicity and progressive alpha-synuclein accumulation in DA neurons. Our study underscores the need to further explore the putative link between parkin dominant toxicity and PD.
Journal of Neuroscience 03/2009; 29(7):1962-76. · 7.11 Impact Factor
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Xiao-Hong Lu
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ABSTRACT: Basal ganglia neurodegenerative disorders, such as Parkinson's disease (PD) and Huntington's disease (HD), are characterized by not only spectrum of motor deficits, ranging form hypokinesia to hyperkinesia, but also emotional, cognitive, and psychiatric manifestations. The symptoms and pathogenic mechanism of these disorders should be viewed as dysfunctions of specific cortico-subcortical neurocircuits. Transgenic approaches using large genomic inserts, such as bacterial artificial chromosome (BAC)-mediated transgenesis, due to its capacity to propagate large-size genomic DNA and faithful production of endogenous-like gene expression pattern/lever, have provided an ideal basis for the generation of transgenic mice as model for basal ganglia neurodegenerative disorders, as well as the functional and structural analysis of neurocircuits. In this chapter, the basic concepts and practical approaches about application of BAC transgenic system are introduced. Existent major BAC transgenic mouse models for PD and HD are evaluated according to their construct, face, and predicative validity. Finally, considerations, possible solutions, and future perspectives of using BAC transgenic approach to study basal ganglia neurodegenerative disorders are discussed.
International Review of Neurobiology 01/2009; 89:37-56. · 2.35 Impact Factor
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ABSTRACT: To observe the expression of hepatocyte nuclear factor 4alpha (HNF4alpha) and the activity of key enzyme glucokinase (GK) in glucose metabolism, and further to investigate the possible mechanism of berberine in treating type 2 diabetes.
Mouse primary hepatocytes were isolated by an improved single two-step perfusion method. The murine hepatocytes were cultured and incubated with berberine (0, 1, 3, 10, 30, 100 micromol x L(-1)) and 1 mmol x L(-1) metformin for 24 h respectively. The mRNA expression of HNF4alpha were quantified by RT-PCR and the protein expression of HNF4alpha were quantified by Western-blot. And the activity of GK were detected with enzyme kinetics method.
As compared with the negative control group, at a certain concentration range, the expression of HNF4alpha mRNA and protein and the activity of GK were promoted by berberine. Both of them reached the top at the concentration of 30 micromol x L(-1) (P<0.01). But the metformin made no difference with the negative control group on the expression of HNF4alpha and the activity of GK.
It is suggested that the effects of berberine on improving glucose metabolism can be mechanically associated with its up-regulating the HNF4a expression and inducing the activity of hepatic glucokinase.
Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica 09/2008; 33(18):2105-9.
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Michelle Gray,
Dyna I Shirasaki,
Carlos Cepeda,
Véronique M André,
Brian Wilburn, Xiao-Hong Lu,
Jifang Tao,
Irene Yamazaki,
Shi-Hua Li,
Yi E Sun,
Xiao-Jiang Li,
Michael S Levine,
X William Yang
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ABSTRACT: To elucidate the pathogenic mechanisms in Huntington's disease (HD) elicited by expression of full-length human mutant huntingtin (fl-mhtt), a bacterial artificial chromosome (BAC)-mediated transgenic mouse model (BACHD) was developed expressing fl-mhtt with 97 glutamine repeats under the control of endogenous htt regulatory machinery on the BAC. BACHD mice exhibit progressive motor deficits, neuronal synaptic dysfunction, and late-onset selective neuropathology, which includes significant cortical and striatal atrophy and striatal dark neuron degeneration. Power analyses reveal the robustness of the behavioral and neuropathological phenotypes, suggesting BACHD as a suitable fl-mhtt mouse model for preclinical studies. Additional analyses of BACHD mice provide novel insights into how mhtt may elicit neuropathogenesis. First, unlike previous fl-mhtt mouse models, BACHD mice reveal that the slowly progressive and selective pathogenic process in HD mouse brains can occur without early and diffuse nuclear accumulation of aggregated mhtt (i.e., as detected by immunostaining with the EM48 antibody). Instead, a relatively steady-state level of predominantly full-length mhtt and a small amount of mhtt N-terminal fragments are sufficient to elicit the disease process. Second, the polyglutamine repeat within fl-mhtt in BACHD mice is encoded by a mixed CAA-CAG repeat, which is stable in both the germline and somatic tissues including the cortex and striatum at the onset of neuropathology. Therefore, our results suggest that somatic repeat instability does not play a necessary role in selective neuropathogenesis in BACHD mice. In summary, the BACHD model constitutes a novel and robust in vivo paradigm for the investigation of HD pathogenesis and treatment.
Journal of Neuroscience 07/2008; 28(24):6182-95. · 7.11 Impact Factor
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ABSTRACT: Antipsychotic treatment during pregnancy is indicated when risk of drug exposure to the fetus is outweighed by the untreated psychosis in the mother. Although increased risk of congenital malformation has not been associated with most available antipsychotic drugs, there is a paucity of knowledge on the subtle neurodevelopmental and behavioral consequences of prenatal receptor blockade by these drugs. In the present study, antipsychotic drugs, sulpiride (SUL, a selective D2 receptor antagonist) and risperidone (RIS, a D2/5HT2 receptor antagonist) were administered to pregnant Sprague-Dawley dams from gestational day 6 to 18. Both RIS and SUL prenatal exposed rats had lower birth body weights compared to controls. RIS exposure had a significant main effect to retard body weight growth in male offspring until postnatal day (PND) 60. Importantly, water maze tests revealed that SUL prenatal exposure impaired visual cue response in visual task performance (stimulus-response, S-R memory), but not place response as reflected in hidden platform task (spatial memory acquisition and retention). In addition, prenatal SUL treatment reduced spontaneous activity as measured in open field. Both behavioral deficits suggest that SUL prenatal exposure may lead to subtle disruption of striatum development and related learning and motor systems. RIS exposure failed to elicit deficits in both water maze tasks and increased rearing in open field test. These results suggest prenatal exposure to SUL and RIS may produce lasting effects on growth, locomotion and memory in rat offspring. And the differences may exist in the effects of antipsychotic drugs which selectively block dopamine D2 receptors (SUL) as compared to second generation drugs (RIS) that potently antagonize serotonin and dopamine receptors.
Progress in Neuro-Psychopharmacology and Biological Psychiatry 03/2008; 32(2):387-97. · 3.25 Impact Factor
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ABSTRACT: The aim of the study was to determine the prevalence and the distribution pattern of lesion site of intracranial vascular stenosis and to identify risk factors for the stenosis in patients with essential hypertension.
A total of 231 consecutive inpatients with essential hypertension were included in this study. Patients with the history of cerebrovascular diseases and relevant neurological symptoms were excluded. Intracranial vascular stenosis (>50% diameter reduction) was detected using CT angiography (CTA).
Of 231 patients, 69 (29.87%) had intracranial artery stenosis. The most common stenosis site is middle cerebral artery (43.69%), followed by carotid siphon (20.39%). The stenosis in internal carotid arterial system (78.64%) was more common than in vertebrobasilar arterial system (21.56%, P < 0.05). The patients with intracranial vascular stenosis were older, had longer history of hypertension, higher levels of systolic blood pressure, higher plasma cholesterol, higher LDL-C. Lp (a), higher urinary microalbumin excretion, thicker ventricular septum, and lower levels of HDL-C than the patients without stenosis. Logistic analysis showed that systolic blood pressure (OR 1.650, 95% CI 1.134 - 2.400, P = 0.023), course of hypertension (OR 1.238, 95% CI 1.072 - 1.429, P = 0.006), LDL-C (OR 2.103, 95% CI 1.157 - 3.823, P = 0.014) and type 2 diabetes (OR 2.325, 95% CI 1.161 - 4.341, P = 0.011) were the independent risk factors of asymptomatic intracranial arterial stenosis.
Nearly 30% inpatients with essential hypertension had asymptomatic intracranial artery stenosis. The most common site of stenosis was middle cerebral artery. Hypertension, dyslipidemia and diabetes were risk factors for the development of intracranial arterial stenosis.
Zhonghua xin xue guan bing za zhi [Chinese journal of cardiovascular diseases] 11/2007; 35(10):893-6.
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ABSTRACT: To observe the effects of Huanglian Jiedu Decoction (HLJDD), a traditional Chinese compound herbal medicine, on p85 mRNA and protein expressions of phosphatidylinositol-3-kinase (PI-3K) in target tissues (skeletal muscular and adipose tissues) in rats with type 2 diabetes mellitus (T2DM) and to investigate the molecular mechanism of HLJDD in treating T2DM.
The male Wistar rats were injected with streptozotocin (STZ) 30 mg/kg through tail vein, and fed with high-fat and high-caloric diets to induce T2DM. Then the rats were randomly divided into untreated group, aspirin-treated group and HLJDD group, and treated correspondingly. Meanwhile, a group of normal animals without any treatment was set up for normal control group. Ten weeks later, serum fasting blood glucose (FBG), serum fasting insulin (FINS) and oral glucose tolerance test (OGTT) were routinely determined. The expressions of PI-3K p85 mRNA and protein in skeletal muscle and adipose tissue were determined with RT-PCR and Western blotting before and after insulin treatment.
Compared with the untreated group, the FBG and OGTT levels in T2DM rats treated with HLJDD decreased significantly (P<0.05). The FINS in HLJDD group was lower than that in the normal control group (P<0.05), but was not significantly different from that in the untreated group. The PI-3K p85 mRNA and protein expressions in HLJDD group obviously increased, as compared with those in the untreated group.
The effect of HLJDD in treating T2DM was probably associated with its improvement of PI-3K p85 mRNA and protein expressions in skeletal muscle and adipose tissue of the T2DM rats.
Journal of Chinese Integrative Medicine 10/2007; 5(5):541-5.
