Figure 1. Hypothesis of our laboratory.

Amyotrophic lateral sclerosis (ALS), Parkinson’s disease (PD), Alzheimer’s disease (AD), SOD1, optineurin, Parkin, Pink1, DJ-1, ATP13A2, LRRK2, α-synuclein, amyloid precursor protein (APP), Presenilin1 (PS1), N-cadherin, mitochondria, misfolded proteins, ER stress, ubiquitin-proteasome system (UPS), induced pluripotent stem cell (iPS cell), high-throughput assay, medaka fish

1. Molecular pathogenesis and treatment of Amyotrophic Lateral Sclerosis (ALS)
2. Parkinson’s disease (PD)
3. Molecular investigation of the pathogenesis of Alzheimer’s disease (AD)

We are now focusing on the two responsible genes for familial ALS, superoxide dismutase 1(SOD1) and Optineurin.
Mutant SOD1 is the most frequent cause of familial ALS and its toxicity depends on the expression level of the mutant protein. We developed and optimized a cell-based, high-throughput assay to identify small molecules that transcriptionally decrease SOD1 expression (Figure 2a). Screening with the assay followed by biochemical analysis identified a number of hit compounds and drugs that selectively downregulate SOD1 expression. We will investigate whether one of these hit drugs can ameliorate the ALS phenotype of mutant SOD1 mice.
Direct reduction of the transcription of pathogenic SOD1 protein provides a new therapeutic strategy for SOD1-mediated ALS.
One of the main difficulties in studying the pathogenesis of ALS is the unavailability of biopsy samples from patients, i.e., spinal cords. We are trying to establish novel in vitro disease models using induced pluripotent stem cells (iPS cells). We have established iPS cells from SOD1 transgenic mice that have been widely used as mouse model for ALS, and have succeeded in inducing motor neuronal differentiation (Figure 2b).
Optineurin is also important for ALS research, because it is virtually the only gene that is thought to cause ALS by loss of its functions. We are knocking down optineurin expression in cultured cells by siRNA (Figure 2c), and are now analyzing the phenotype and downstream signals.
Several lines of evidence have shown that the disturbance of the ubiquitin-proteasome system (UPS), one of the cell’s protein degradation systems, is associated with ALS in model animals and cells (Figure 2d). We therefore established model mice with dysfunctional UPS by using the Cre-loxP system. Models with motor neuron-specific UPS dysfunction showed movement disorders and pathological findings present in sporadic ALS cases. We are continuing to study the pathological mechanisms behind ALS with this new ALS mouse model.

2. Parkinson’s disease (PD)

　Parkinson’s disease (PD) is the most common movement disorder, and the second most common neurodegenerative disorder after Alzheimer’s disease, affecting about 1-2% of people over 65 years. Although the etiology PD is still unknown, about 10% of PD cases are familial. Parkin, Pink1, DJ-1 and ATP13A2 are causative genes for autosomal recessive PD, while LRRK2 and α-synuclein are for autosomal dominant PD.
 The final goal of our research is to develop treatments for idiopathic PD by understanding the pathogenesis of familial as well as idiopathic PD.

(1) Autosomal recessive PD

a) The role of Parkin and Pink1 especially on maintenance of mitochondrial function by using cellular systems and genetically engineered Drosophila and medaka fish.

Figure 3a. PINK1 and Parkin act together with Miro, to keep the mitochondrial quality control

b) Drug screening modifying functions and interactions of Parkin and Pink1.
c) The role of DJ-1 by using genetically engineered DT40 cell line.
d) The role of ATP13A2 by using genetically engineered medaka fish.

3. Molecular investigation of the pathogenesis of Alzheimer’s Disease (AD).

　AD is poised to become a significant public health crisis. The occurrence of AD is largely sporadic, typically affecting individuals over 65 years. Deposition of amyloid plaques is one of the pathological hallmarks of AD. Amyloid plaques are composed of β-amyloid (Aβ), which are derived from the amyloid precursor protein (APP) via proteolytic cleavage by β- and γ-secretases.  Presenilin 1 (PS1), a causative gene for familial AD is found to be the enzymatic core of γ-secretase. A widely accepted hypothesis on AD pathogenesis is the amyloid hypothesis where Aβ plays a crucial role in neurodegeneration.
Current studies predict that the Aβ oligomer is a potent toxin for synapses. Indeed, synapse loss is another feature of AD pathology. For example, the degree of synapse loss is significantly correlated to the magnitude of cognitive decline. In this sense, AD can be recognized as a “Synapse disease”. In our group, we focus on the function of PS1 as well as that of N-cadherin, an essential adhesion molecule for synaptic contact, to elucidate the pathophysiology underlying AD.
On the other hand, there are a number of modifiable risk factors for AD. For instance, hypertension, diabetes mellitus and hyperlipidemia (metabolic syndrome) are believed to increase the risk of AD. Conversely, social activity, education and exercise are protective against cognitive decline. We are also focusing on these modifiable risk factors for AD and investigating the molecular mechanisms by which these risk factors affect AD pathology, using APP transgenic mice presenting metabolic syndrome (Figure 4).

Figure 4. A: APP-high fat diet (HFD) model (mimicking metabolic syndrome) and environmental enrichment (EE). B: HFD worsens the cognitive function of APP model mice, whereas EE ameliorates it (demonstrated by Morris Water Maze test).

Current lab members:
Staff

Graduate Students

Technical Staff

Secretary

Address correspondence:
Section of Molecular Neuroscience (4th laboratory)
Department of Neurology,
Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto City, Kyoto 606-8507
Tel: +81-75-751-4397
Fax: +81-75-751-9780

Parkin interacts with Klokin1 for mitochondrial import and maintenance of membrane potential.
Kuroda Y, Sako W, Goto S, Sawada T, Uchida D, Izumi Y, Takahashi T, Kagawa N, Matsumoto M, Matsumoto M, Takahashi R, Kaji R, Mitsui T.
Hum Mol Genet. 2012 Mar 1;21(5):991-1003.

Environmental enrichment ameliorated high-fat diet-induced Aβ deposition and memory deficit in APP transgenic mice.
Maesako M, Uemura K, Kubota M, Kuzuya A, Sasaki K, Asada M, Watanabe K, Hayashida N, Ihara M, Ito H, Shimohama S, Kihara T, Kinoshita A.
Neurobiol Aging. 2011 Dec 23. [Epub ahead of print]

Cell therapy for brain diseases: Perspective and future prospects.
Takahashi R, Kondo T.
Rinsho Shinkeigaku. 2011 Nov;51(11):1075-7.

N-cadherin enhances APP dimerization at the extracellular domain and modulates Aβ production.
Asada-Utsugi M, Uemura K, Noda Y, Kuzuya A, Maesako M, Ando K, Kubota M, Watanabe K, Takahashi M, Kihara T, Shimohama S, Takahashi R, Berezovska O, Kinoshita A.
J Neurochem. 2011 Oct;119(2):354-63.

P301S mutant human tau transgenic mice manifest early symptoms of human tauopathies with dementia and altered sensorimotor gating.
Takeuchi H, Iba M, Inoue H, Higuchi M, Takao K, Tsukita K, Karatsu Y, Iwamoto Y, Miyakawa T, Suhara T, Trojanowski JQ, Lee VM, Takahashi R.
PLoS One. 2011;6(6):e21050.

Presenilin regulates insulin signaling via a gamma-secretase-independent mechanism.
Maesako M, Uemura K, Kuzuya A, Sasaki K, Asada M, Watanabe K, Ando K, Kubota M, Kihara T, Kinoshita A.
J Biol Chem. 2011 Jul 15;286(28):25309-16.

Optineurin is co-localized with FUS in basophilic inclusions of ALS with FUS mutation and in basophilic inclusion body disease.
Ito H, Fujita K, Nakamura M, Wate R, Kaneko S, Sasaki S, Yamane K, Suzuki N, Aoki M, Shibata N, Togashi S, Kawata A, Mochizuki Y, Mizutani T, Maruyama H, Hirano A, Takahashi R, Kawakami H, Kusaka H.
Acta Neuropathol. 2011 Apr;121(4):555-7.

Chemical library screening identifies a small molecule that downregulates SOD1 transcription for drugs to treat amyotrophic lateral sclerosis.
Murakami G, Inoue H, Tsukita K, Asai Y, Amagai Y, Aiba K, Shimogawa H, Uesugi M, Nakatsuji N, Takahashi R.
J Biomol Screen. 2011 Apr;16(4):405-14.

The endoplasmic reticulum stress sensor, ATF6α, protects against neurotoxin-induced dopaminergic neuronal death.
Egawa N, Yamamoto K, Inoue H, Hikawa R, Nishi K, Mori K, Takahashi R.
J Biol Chem. 2011 Mar 11;286(10):7947-57.

N-cadherin regulates p38 MAPK signaling via association with JNK-associated leucine zipper protein: implications for neurodegeneration in Alzheimer disease.
Ando K, Uemura K, Kuzuya A, Maesako M, Asada-Utsugi M, Kubota M, Aoyagi N, Yoshioka K, Okawa K, Inoue H, Kawamata J, Shimohama S, Arai T, Takahashi R, Kinoshita A.
J Biol Chem. 2011 Mar 4;286(9):7619-28.

Ammonium chloride and tunicamycin are novel toxins for dopaminergic neurons and induce Parkinson’s disease-like phenotypes in medaka fish.
Matsui H, Ito H, Taniguchi Y, Takeda S, Takahashi R.
J Neurochem. 2010 Dec;115(5):1150-60.

The loss of PGAM5 suppresses the mitochondrial degeneration caused by inactivation of PINK1 in Drosophila.
Imai Y, Kanao T, Sawada T, Kobayashi Y, Moriwaki Y, Ishida Y, Takeda K, Ichijo H, Lu B, Takahashi R.
PLoS Genet. 2010 Dec 2;6(12):e1001229.

Localization of HtrA2/Omi immunoreactivity in brains affected by Alzheimer’s disease.
Kawamoto Y, Ito H, Kobayashi Y, Suzuki Y, Takahashi R.
Neuroreport. 2010 Dec 8;21(17):1121-5.

Proteasome inhibition in medaka brain induces the features of Parkinson’s disease.
Matsui H, Ito H, Taniguchi Y, Inoue H, Takeda S, Takahashi R.
J Neurochem. 2010 Oct;115(1):178-87.

Insulin regulates Presenilin 1 localization via PI3K/Akt signaling.
Maesako M, Uemura K, Kubota M, Ando K, Kuzuya A, Asada M, Kihara T, Kinoshita A.
Neurosci Lett. 2010 Oct 15;483(3):157-61.

Induction of protective immunity by vaccination with wild-type apo superoxide dismutase 1 in mutant SOD1 transgenic mice.
Takeuchi S, Fujiwara N, Ido A, Oono M, Takeuchi Y, Tateno M, Suzuki K, Takahashi R, Tooyama I, Taniguchi N, Julien JP, Urushitani M.
J Neuropathol Exp Neurol. 2010 Oct;69(10):1044-56.

Mutations in LGI1 gene in Japanese families with autosomal dominant lateral temporal lobe epilepsy: the first report from Asian families.
Kawamata J, Ikeda A, Fujita Y, Usui K, Shimohama S, Takahashi R.
Epilepsia. 2010 Apr;51(4):690-3.

Loss of PINK1 in medaka fish (Oryzias latipes) causes late-onset decrease in spontaneous movement.
Matsui H, Taniguchi Y, Inoue H, Kobayashi Y, Sakaki Y, Toyoda A, Uemura K, Kobayashi D, Takeda S, Takahashi R.
Neurosci Res. 2010 Feb;66(2):151-61.

PI3K inhibition causes the accumulation of ubiquitinated presenilin 1 without affecting the proteasome activity.
Aoyagi N, Uemura K, Kuzuya A, Kihara T, Kawamata J, Shimohama S, Kinoshita A, Takahashi R.
Biochem Biophys Res Commun. 2010 Jan 8;391(2):1240-5.

[Pathogenesis of sporadic Parkinson’s disease: contribution of genetic and environmental risk factors].
Takahashi R, Kawamata J, Takeuchi H.
Rinsho Shinkeigaku. 2009 Nov;49(11):885-7. Review. Japanese.

A chemical neurotoxin, MPTP induces Parkinson’s disease like phenotype, movement disorders and persistent loss of dopamine neurons in medaka fish.
Matsui H, Taniguchi Y, Inoue H, Uemura K, Takeda S, Takahashi R.
Neurosci Res. 2009 Nov;65(3):263-71.

17th Symposium on the Treatment of Parkinson’s Disease. September 27, 2008, Tokyo. Foreword.
Kuzuhara S, Takahashi R.
J Neurol. 2009 Aug;256 Suppl 3:269.

[Frontier researches for the development of molecular-targeted therapies for familial Parkinson disease].
Imai Y, Takahashi R.
Brain Nerve. 2009 Aug;61(8):903-13.

Edaravone in ALS.
Takahashi R.
Exp Neurol. 2009 Jun;217(2):235-6.

[Pathological mechanisms of Parkinson’s disease].
Matsui H, Takahashi R.
Brain Nerve. 2009 Apr;61(4):441-6.

Nicotinic receptor stimulation protects nigral dopaminergic neurons in rotenone-induced Parkinson’s disease models.
Takeuchi H, Yanagida T, Inden M, Takata K, Kitamura Y, Yamakawa K, Sawada H, Izumi Y, Yamamoto N, Kihara T, Uemura K, Inoue H, Taniguchi T, Akaike A, Takahashi R, Shimohama S.
J Neurosci Res. 2009 Feb;87(2):576-85.

N-cadherin-based adhesion enhances Abeta release and decreases Abeta42/40 ratio.
Uemura K, Lill CM, Banks M, Asada M, Aoyagi N, Ando K, Kubota M, Kihara T, Nishimoto T, Sugimoto H, Takahashi R, Hyman BT, Shimohama S, Berezovska O, Kinoshita A.
Neurochem. 2009 Jan;108(2):350-60.

Phosphorylation of 4E-BP by LRRK2 affects the maintenance of dopaminergic neurons in Drosophila.
Imai Y, Gehrke S, Wang HQ, Takahashi R, Hasegawa K, Oota E, Lu B.
EMBO J. 2008 Sep 17;27(18):2432-43.

[Recent progress and future direction of neurodegenerative disease research].
Takahashi R.
Rinsho Shinkeigaku. 2008 Nov;48(11):903-5.

Pael-R transgenic mice crossed with parkin deficient mice displayed progressive and selective catecholaminergic neuronal loss.
Wang HQ, Imai Y, Inoue H, Kataoka A, Iita S, Nukina N, Takahashi R.
J Neurochem. 2008 Oct;107(1):171-85.

Pael receptor is involved in dopamine metabolism in the nigrostriatal system.
Imai Y, Inoue H, Kataoka A, Hua-Qin W, Masuda M, Ikeda T, Tsukita K, Soda M, Kodama T, Fuwa T, Honda Y, Kaneko S, Matsumoto S, Wakamatsu K, Ito S, Miura M, Aosaki T, Itohara S, Takahashi R.
Neurosci Res. 2007 Dec;59(4):413-25.

[Animal models for familial Parkinson’s disease].
Takahashi R.
Rinsho Shinkeigaku. 2007 Nov;47(11):938-40.

Heat-shock protein 105 interacts with and suppresses aggregation of mutant Cu/Zn superoxide dismutase: clues to a possible strategy for treating ALS.
Yamashita H, Kawamata J, Okawa K, Kanki R, Nakamizo T, Hatayama T, Yamanaka K, Takahashi R, Shimohama S.
J Neurochem. 2007 Sep;102(5):1497-505.

[Pathogenesis of Parkinson disease].
Takeuchi H, Takahashi R.
Nihon Ronen Igakkai Zasshi. 2007 Jul;44(4):415-21.

Expanding insights on the involvement of endoplasmic reticulum stress in Parkinson’s disease.
Wang HQ, Takahashi R.
Antioxid Redox Signal. 2007 May;9(5):553-61.

Cell type-specific upregulation of Parkin in response to ER stress.
Wang HQ, Imai Y, Kataoka A, Takahashi R.
Antioxid Redox Signal. 2007 May;9(5):533-42.

Presenilin 1 is involved in the maturation of beta-site amyloid precursor protein-cleaving enzyme 1 (BACE1).
Kuzuya A, Uemura K, Kitagawa N, Aoyagi N, Kihara T, Ninomiya H, Ishiura S, Takahashi R, Shimohama S.
J Neurosci Res. 2007 Jan;85(1):153-65.

[Ubiquitin and Parkinson’s disease].
Tashiro Y, Takahashi R.
Tanpakushitsu Kakusan Koso. 2006 Aug;51(10 Suppl):1413-7. Review. Japanese. No abstract available.