Antagonistic roles of canonical and Alternative-RPA in disease-associated tandem CAG repeat instability.

Expansions of repeat DNA tracts cause >70 diseases, and ongoing expansions in brains exacerbate disease. During expansion mutations, single-stranded DNAs (ssDNAs) form slipped-DNAs. We find the ssDNA-binding complexes canonical replication protein A (RPA1, RPA2, and RPA3) and Alternative-RPA (RPA1, RPA3, and primate-specific RPA4) are upregulated in Huntington disease and spinocerebellar ataxia type 1 (SCA1) patient brains. Protein interactomes of RPA and Alt-RPA reveal unique and shared partners, including modifiers of CAG instability and disease presentation. RPA enhances in vitro melting, FAN1 excision, and repair of slipped-CAGs and protects against CAG expansions in human cells. RPA overexpression in SCA1 mouse brains ablates expansions, coincident with decreased ATXN1 aggregation, reduced brain DNA damage, improved neuron morphology, and rescued motor phenotypes. In contrast, Alt-RPA inhibits melting, FAN1 excision, and repair of slipped-CAGs and promotes CAG expansions. These findings suggest a functional interplay between the two RPAs where Alt-RPA may antagonistically offset RPA's suppression of disease-associated repeat expansions, which may extend to other DNA processes.

Necrosis Links Neurodegeneration and Neuroinflammation in Neurodegenerative Disease.

The mechanisms of neuronal cell death in neurodegenerative disease remain incompletely understood, although recent studies have made significant advances. Apoptosis was previously considered to be the only mechanism of neuronal cell death in neurodegenerative diseases. However, recent findings have challenged this dogma, identifying new subtypes of necrotic neuronal cell death. The present review provides an updated summary of necrosis subtypes and discusses their potential roles in neurodegenerative cell death. Among numerous necrosis subtypes, including necroptosis, paraptosis, ferroptosis, and pyroptosis, transcriptional repression-induced atypical cell death (TRIAD) has been identified as a potential mechanism of neuronal cell death. TRIAD is induced by functional deficiency of TEAD-YAP and self-amplifies via the release of HMGB1. TRIAD is a feasible potential mechanism of neuronal cell death in Alzheimer's disease and other neurodegenerative diseases. In addition to induction of cell death, HMGB1 released during TRIAD activates brain inflammatory responses, which is a potential link between neurodegeneration and neuroinflammation.

Drebrin-like (Dbnl) Controls Neuronal Migration via Regulating N-Cadherin Expression in the Developing Cerebral Cortex.

The actin cytoskeleton is crucial for neuronal migration in the mammalian developing cerebral cortex. The adaptor protein Drebrin-like (Dbnl) plays important roles in reorganization of the actin cytoskeleton, dendrite formation, and endocytosis by interacting with F-actin, cobl, and dynamin. Although Dbnl is known to be expressed in the brain, the functions of this molecule during brain development are largely unknown. In this study, to examine the roles of Dbnl in the developing cerebral cortex, we conducted experiments using mice of both sexes with knockdown of Dbnl, effected by in utero electroporation, in the migrating neurons of the embryonic cortex. Time-lapse imaging of the Dbnl-knockdown neurons revealed that the presence of Dbnl is a prerequisite for appropriate formation of processes in the multipolar neurons in the multipolar cell accumulation zone or the deep part of the subventricular zone, and for neuronal polarization and entry into the cortical plate. We found that Dbnl knockdown decreased the amount of N-cadherin protein expressed on the plasma membrane of the cortical neurons. The defect in neuronal migration caused by Dbnl knockdown was rescued by moderate overexpression of N-cadherin and αN-catenin or by transfection of the phospho-mimic form (Y337E, Y347E), but not the phospho-resistant form (Y337F, Y347F), of Dbnl. These results suggest that Dbnl controls neuronal migration, neuronal multipolar morphology, and cell polarity in the developing cerebral cortex via regulating N-cadherin expression.SIGNIFICANCE STATEMENT Disruption of neuronal migration can cause neuronal disorders, such as lissencephaly and subcortical band heterotopia. During cerebral cortical development, the actin cytoskeleton plays a key role in neuronal migration; however, the mechanisms of regulation of neuronal migration by the actin cytoskeleton still remain unclear. Herein, we report that the novel protein Dbnl, an actin-binding protein, controls multiple events during neuronal migration in the developing mouse cerebral cortex. We also showed that this regulation is mediated by phosphorylation of Dbnl at tyrosine residues 337 and 347 and αN-catenin/N-cadherin, suggesting that the Dbnl-αN-catenin/N-cadherin pathway is important for neuronal migration in the developing cortex.

PQBP1, an intellectual disability causative gene, affects bone development and growth.

Polyglutamine tract-binding protein 1 (PQBP1), an intellectual disability causative gene, is involved in transcriptional and post-transcriptional regulation of gene expression in animals, and possibly also in plants. In our previous work, reduced brain size, associated with an elongated cell cycle duration in neural stem cells (NSCs), was observed in the NSCs conditional Pqbp1 gene knockout (cKO) mice, which mimic microcephaly patients. However, the physiological significance of PQBP1 in bone metabolism has not been elucidated. Here, we analyzed the bone phenotype of nestin-Cre Pqbp1-cKO mice. Surprisingly, the Pqbp1-cKO mice were significantly shorter than control mice and had a lower bone mass, shown by micro-computed tomography. Furthermore, bone histology showed impaired bone formation in the Pqbp1-cKO mice as well as a chondrocyte deficiency. Real-time PCR analysis showed reduced osteoblast- and chondrocyte-related gene expression in the Pqbp1-cKO mice, while the osteoclast-related gene expression remained unchanged. These results suggest that PQBP1 in bone marrow mesenchymal stem cells may play a crucial role in bone formation and cartilage development.

The intellectual disability gene PQBP1 rescues Alzheimer's disease pathology.

Early-phase pathologies of Alzheimer's disease (AD) are attracting much attention after clinical trials of drugs designed to remove beta-amyloid (Aß) aggregates failed to recover memory and cognitive function in symptomatic AD patients. Here, we show that phosphorylation of serine/arginine repetitive matrix 2 (SRRM2) at Ser1068, which is observed in the brains of early phase AD mouse models and postmortem end-stage AD patients, prevents its nuclear translocation by inhibiting interaction with T-complex protein subunit α. SRRM2 deficiency in neurons destabilized polyglutamine binding protein 1 (PQBP1), a causative gene for intellectual disability (ID), greatly affecting the splicing patterns of synapse-related genes, as demonstrated in a newly generated PQBP1-conditional knockout model. PQBP1 and SRRM2 were downregulated in cortical neurons of human AD patients and mouse AD models, and the AAV-PQBP1 vector recovered RNA splicing, the synapse phenotype, and the cognitive decline in the two mouse models. Finally, the kinases responsible for the phosphorylation of SRRM2 at Ser1068 were identified as ERK1/2 (MAPK3/1). These results collectively reveal a new aspect of AD pathology in which a phosphorylation signal affecting RNA splicing and synapse integrity precedes the formation of extracellular Aß aggregates and may progress in parallel with tau phosphorylation.

RpA1 ameliorates symptoms of mutant ataxin-1 knock-in mice and enhances DNA damage repair.

DNA damage and repair is a critical domain of many neurodegenerative diseases. In this study, we focused on RpA1, a candidate key molecule in polyQ disease pathologies, and tested the therapeutic effect of adeno-associated virus (AAV) vector expressing RpA1 on mutant Ataxin-1 knock-in (Atxn1-KI) mice. We found significant effects on motor functions, normalized DNA damage markers (γH2AX and 53BP1), and improved Purkinje cell morphology; effects that lasted for 50 weeks following AAV-RpA1 infection. In addition, we confirmed that AAV-RpA1 indirectly recovered multiple cellular functions such as RNA splicing, transcription and cell cycle as well as abnormal morphology of dendrite and dendritic spine of Purkinje cells in Atxn1-KI mice. All these results suggested a possibility of gene therapy with RpA1 for SCA1.

Targeting TEAD/YAP-transcription-dependent necrosis, TRIAD, ameliorates Huntington's disease pathology.

Neuronal cell death in neurodegenerative diseases is not fully understood. Here we report that mutant huntingtin (Htt), a causative gene product of Huntington's diseases (HD) selectively induces a new form of necrotic cell death, in which endoplasmic reticulum (ER) enlarges and cell body asymmetrically balloons and finally ruptures. Pharmacological and genetic analyses revealed that the necrotic cell death is distinct from the RIP1/3 pathway-dependent necroptosis, but mediated by a functional deficiency of TEAD/YAP-dependent transcription. In addition, we revealed that a cell cycle regulator, Plk1, switches the balance between TEAD/YAP-dependent necrosis and p73/YAP-dependent apoptosis by shifting the interaction partner of YAP from TEAD to p73 through YAP phosphorylation at Thr77. In vivo ER imaging with two-photon microscopy detects similar ER enlargement, and viral vector-mediated delivery of YAP as well as chemical inhibitors of the Hippo pathway such as S1P recover the ER instability and necrosis in HD model mice. Intriguingly S1P completely stops the decline of motor function of HD model mice even after the onset of symptom. Collectively, we suggest approaches targeting the signalling pathway of TEAD/YAP-transcription-dependent necrosis (TRIAD) could lead to a therapeutic development against HD.

Comprehensive phosphoproteome analysis unravels the core signaling network that initiates the earliest synapse pathology in preclinical Alzheimer's disease brain.

Using a high-end mass spectrometry, we screened phosphoproteins and phosphopeptides in four types of Alzheimer's disease (AD) mouse models and human AD postmortem brains. We identified commonly changed phosphoproteins in multiple models and also determined phosphoproteins related to initiation of amyloid beta (Aß) deposition in the mouse brain. After confirming these proteins were also changed in and human AD brains, we put the proteins on experimentally verified protein-protein interaction databases. Surprisingly, most of the core phosphoproteins were directly connected, and they formed a functional network linked to synaptic spine formation. The change of the core network started at a preclinical stage even before histological Aß deposition. Systems biology analyses suggested that phosphorylation of myristoylated alanine-rich C-kinase substrate (MARCKS) by overactivated kinases including protein kinases C and calmodulin-dependent kinases initiates synapse pathology. Two-photon microscopic observation revealed recovery of abnormal spine formation in the AD model mice by targeting a core protein MARCKS or by inhibiting candidate kinases, supporting our hypothesis formulated based on phosphoproteome analysis.

Systems biology analysis of Drosophila in vivo screen data elucidates core networks for DNA damage repair in SCA1.

DNA damage repair is implicated in neurodegenerative diseases; however, the relative contributions of various DNA repair systems to the pathology of these diseases have not been investigated systematically. In this study, we performed a systematic in vivo screen of all available Drosophila melanogaster homolog DNA repair genes, and we tested the effect of their overexpression on lifespan and developmental viability in Spinocerebellar Ataxia Type 1 (SCA1) Drosophila models expressing human mutant Ataxin-1 (Atxn1). We identified genes previously unknown to be involved in CAG-/polyQ-related pathogenesis that function in multiple DNA damage repair systems. Beyond the significance of each repair system, systems biology analyses unraveled the core networks connecting positive genes in the gene screen that could contribute to SCA1 pathology. In particular, RpA1, which had the largest effect on lifespan in the SCA1 fly model, was located at the hub position linked to such core repair systems, including homologous recombination (HR). We revealed that Atxn1 actually interacted with RpA1 and its essential partners BRCA1/2. Furthermore, mutant but not normal Atxn1 impaired the dynamics of RpA1 in the nucleus after DNA damage. Uptake of BrdU by Purkinje cells was observed in mutant Atxn1 knockin mice, suggesting their abnormal entry to the S-phase. In addition, chemical and genetic inhibitions of Chk1 elongated lifespan and recovered eye degeneration. Collectively, we elucidated core networks for DNA damage repair in SCA1 that might include the aberrant usage of HR.

Effects of 3,3',5-triiodothyronine on microglial functions.

L-tri-iodothyronine (3, 3', 5-triiodothyronine; T3) is an active form of the thyroid hormone (TH) essential for the development and function of the CNS. Though nongenomic effect of TH, its plasma membrane-bound receptor, and its signaling has been identified, precise function in each cell type of the CNS remained to be investigated. Clearance of cell debris and apoptotic cells by microglia phagocytosis is a critical step for the restoration of damaged neuron-glia networks. Here we report nongenomic effects of T3 on microglial functions. Exposure to T3 increased migration, membrane ruffling and phagocytosis of primary cultured mouse microglia. Injection of T3 together with stab wound attracted more microglia to the lesion site in vivo. Blocking TH transporters and receptors (TRs) or TRα-knock-out (KO) suppressed T3-induced microglial migration and morphological change. The T3-induced microglial migration or membrane ruffling was attenuated by inhibiting Gi /o -protein as well as NO synthase, and subsequent signaling such as phosphoinositide 3-kinase (PI3K), mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK). Inhibitors for Na(+) /K(+) -ATPase, reverse mode of Na(+) /Ca(2+) exchanger (NCX), and small-conductance Ca(2+) -dependent K(+) (SK) channel also attenuated microglial migration or phagocytosis. Interestingly, T3-induced microglial migration, but not phagocytosis, was dependent on GABAA and GABAB receptors, though GABA itself did not affect migratory aptitude. Our results demonstrate that T3 modulates multiple functional responses of microglia via multiple complex mechanisms, which may contribute to physiological and/or pathophysiological functions of the CNS.

Dynamic molecular network analysis of iPSC-Purkinje cells differentiation delineates roles of ISG15 in SCA1 at the earliest stage.

Better understanding of the earliest molecular pathologies of all neurodegenerative diseases is expected to improve human therapeutics. We investigated the earliest molecular pathology of spinocerebellar ataxia type 1 (SCA1), a rare familial neurodegenerative disease that primarily induces death and dysfunction of cerebellum Purkinje cells. Extensive prior studies have identified involvement of transcription or RNA-splicing factors in the molecular pathology of SCA1. However, the regulatory network of SCA1 pathology, especially central regulators of the earliest developmental stages and inflammatory events, remains incompletely understood. Here, we elucidated the earliest developmental pathology of SCA1 using originally developed dynamic molecular network analyses of sequentially acquired RNA-seq data during differentiation of SCA1 patient-derived induced pluripotent stem cells (iPSCs) to Purkinje cells. Dynamic molecular network analysis implicated histone genes and cytokine-relevant immune response genes at the earliest stages of development, and revealed relevance of ISG15 to the following degradation and accumulation of mutant ataxin-1 in Purkinje cells of SCA1 model mice and human patients.

Expression, subunit composition, and function of AMPA-type glutamate receptors are changed in activated microglia; possible contribution of GluA2 (GluR-B)-deficiency under pathological conditions.

Microglia express AMPA (α-amino-hydroxy-5-methyl-isoxazole-4-propionate)-type of glutamate (Glu) receptors (AMPAR), which are highly Ca(2+) impermeable due to the expression of GluA2. However, the functional importance of AMPAR in microglia remains to be investigated, especially under pathological conditions. As low expression of GluA2 was reported in some neurodegenerative diseases, GluA2(-/-) mice were used to show the functional change of microglial AMPARs in response to Glu or kainate (KA). Here we found that Glu-induced currents in the presence of 100 µM cyclothiazide, an inhibitor of AMPAR desensitization, showed time-dependent decrease after activation of microglia with lipopolysaccharide (LPS) in GluA2(+/+) microglia, but not in GluA2(-/-) microglia. Upon activation of microglia, expression level of GluA2 subunits significantly increased, while expression of GluA1, A3 and A4 subunits on membrane surface significantly decreased. These results suggest that nearly homomeric GluA2 subunits were the main reason for low conductance of AMPAR in activated microglia. Increased expression of GluA2 in microglia was also detected partially in brain slices from LPS-injected mice. Cultured microglia from GluA2(-/-) mice showed higher Ca(2+) -permeability, consequently inducing significant increase in the release of proinflammatory cytokine, such as TNF-α. The conditioning medium from KA-treated GluA2(-/-) microglia had more neurotoxic effect on wild type cultured neurons than that from KA-treated GluA2(+/+) microglia. These results suggest that membrane translocation of GluA2-containing AMPARs in activated microglia has functional importance and thus, dysfunction or decreased expression of GluA2 may accelerate Glu neurotoxicity via excess release of proinflammatory cytokines from microglia.

CD38 is critical for social behaviour by regulating oxytocin secretion.

CD38, a transmembrane glycoprotein with ADP-ribosyl cyclase activity, catalyses the formation of Ca2+ signalling molecules, but its role in the neuroendocrine system is unknown. Here we show that adult CD38 knockout (CD38-/-) female and male mice show marked defects in maternal nurturing and social behaviour, respectively, with higher locomotor activity. Consistently, the plasma level of oxytocin (OT), but not vasopressin, was strongly decreased in CD38-/- mice. Replacement of OT by subcutaneous injection or lentiviral-vector-mediated delivery of human CD38 in the hypothalamus rescued social memory and maternal care in CD38-/- mice. Depolarization-induced OT secretion and Ca2+ elevation in oxytocinergic neurohypophysial axon terminals were disrupted in CD38-/- mice; this was mimicked by CD38 metabolite antagonists in CD38+/+ mice. These results reveal that CD38 has a key role in neuropeptide release, thereby critically regulating maternal and social behaviours, and may be an element in neurodevelopmental disorders.

Mutant α-synuclein propagates via the lymphatic system of the brain in the monomeric state.

Prion-like protein propagation is considered a common pathogenic mechanism in neurodegenerative diseases. Here we investigate the in vivo propagation pattern and aggregation state of mutant α-synuclein by injecting adeno-associated viral (AAV)-α-synuclein-A53T-EGFP into the mouse olfactory cortex. Comparison of aggregation states in various brain regions at multiple time points after injection using western blot analyses shows that the monomeric state of the mutant/misfolded protein propagates to remote brain regions by 2 weeks and that the propagated proteins aggregate in situ after being incorporated into neurons. Moreover, injection of Alexa 488-labeled α-synuclein-A53T confirms the monomeric propagation at 2 weeks. Super-resolution microscopy shows that both α-synuclein-A53T proteins propagate via the lymphatic system, penetrate perineuronal nets, and reach the surface of neurons. Electron microscopy shows that the propagated mutant/misfolded monomer forms fibrils characteristic of Parkinson's disease after its incorporation into neurons. These findings suggest a mode of propagation different from that of aggregate-dependent propagation.

PQBP5/NOL10 maintains and anchors the nucleolus under physiological and osmotic stress conditions.

Polyglutamine binding protein 5 (PQBP5), also called nucleolar protein 10 (NOL10), binds to polyglutamine tract sequences and is expressed in the nucleolus. Using dynamic imaging of high-speed atomic force microscopy, we show that PQBP5/NOL10 is an intrinsically disordered protein. Super-resolution microscopy and correlative light and electron microscopy method show that PQBP5/NOL10 makes up the skeletal structure of the nucleolus, constituting the granule meshwork in the granular component area, which is distinct from other nucleolar substructures, such as the fibrillar center and dense fibrillar component. In contrast to other nucleolar proteins, which disperse to the nucleoplasm under osmotic stress conditions, PQBP5/NOL10 remains in the nucleolus and functions as an anchor for reassembly of other nucleolar proteins. Droplet and thermal shift assays show that the biophysical features of PQBP5/NOL10 remain stable under stress conditions, explaining the spatial role of this protein. PQBP5/NOL10 can be functionally depleted by sequestration with polyglutamine disease proteins in vitro and in vivo, leading to the pathological deformity or disappearance of the nucleolus. Taken together, these findings indicate that PQBP5/NOL10 is an essential protein needed to maintain the structure of the nucleolus.

AAV-mediated editing of PMP22 rescues Charcot-Marie-Tooth disease type 1A features in patient-derived iPS Schwann cells.

BACKGROUND: Charcot-Marie-Tooth disease type 1A (CMT1A) is one of the most common hereditary peripheral neuropathies caused by duplication of 1.5 Mb genome region including PMP22 gene. We aimed to correct the duplication in human CMT1A patient-derived iPS cells (CMT1A-iPSCs) by genome editing and intended to analyze the effect on Schwann cells differentiated from CMT1A-iPSCs. METHODS: We designed multiple gRNAs targeting a unique sequence present at two sites that sandwich only a single copy of duplicated peripheral myelin protein 22 (PMP22) genes, and selected one of them (gRNA3) from screening their efficiencies by T7E1 mismatch detection assay. AAV2-hSaCas9-gRNAedit was generated by subcloning gRNA3 into pX601-AAV-CMV plasmid, and the genome editing AAV vector was infected to CMT1A-iPSCs or CMT1A-iPSC-derived Schwann cell precursors. The effect of the genome editing AAV vector on myelination was evaluated by co-immunostaining of myelin basic protein (MBP), a marker of mature myelin, and microtubule-associated protein  2(MAP2), a marker of neurites or by electron microscopy. RESULTS: Here we show that infection of CMT1A-iPS cells (iPSCs) with AAV2-hSaCas9-gRNAedit expressing both hSaCas9 and gRNA targeting the tandem repeat sequence decreased PMP22 gene duplication by 20-40%. Infection of CMT1A-iPSC-derived Schwann cell precursors with AAV2-hSaCas9-gRNAedit normalized PMP22 mRNA and PMP22 protein expression levels, and also ameliorated increased apoptosis and impaired myelination in CMT1A-iPSC-derived Schwann cells. CONCLUSIONS: In vivo transfer of AAV2-hSaCas9-gRNAedit to peripheral nerves could be a potential therapeutic modality for CMT1A patient after careful examinations of toxicity including off-target mutations.

Charcot-Marie-Tooth disease type 1A (CMT1A) is a common heritable form of the condition that develops when nerves in the body's extremities, such as the hands, feet and arms, are damaged due to an extra copy of PMP22 gene being incorrectly produced. Currently, no known therapies exist. Here, we developed a method to delete the additional copy of PMP22 gene by 20­40% to prevent overproduction. Our results show that this method can reduce PMP22 protein production, leading to near normal production in patient's nerve cells. Further safety assessments should now be undertaken. If the treatment is safe for patients it could become a therapeutic option for CMT1A patients.

IL-6 receptor is a possible target against growth of metastasized lung tumor cells in the brain.

In the animal model of brain metastasis using human lung squamous cell carcinoma-derived cells (HARA-B) inoculated into the left ventricle of the heart of nude mice, metastasized tumor cells and brain resident cells interact with each other. Among them, tumor cells and astrocytes have been reported to stimulate each other, releasing soluble factors from both sides, subsequently promoting tumor growth significantly. Among the receptors for soluble factors released from astrocytes, only IL-6 receptor (IL-6R) on tumor cells was up-regulated during the activation with astrocytes. Application of monoclonal antibody against human IL-6R (tocilizumab) to the activated HARA-B cells, the growth of HARA-B cells stimulated by the conditioned medium of HARA-B/astrocytes was significantly inhibited. Injecting tocilizumab to animal models of brain metastasis starting at three weeks of inoculation of HARA-B cells, two times a week for three weeks, significantly inhibited the size of the metastasized tumor foci. The up-regulated expression of IL-6R on metastasized lung tumor cells was also observed in the tissue from postmortem patients. These results suggest that IL-6R on metastasized lung tumor cells would be a therapeutic target to inhibit the growth of the metastasized lung tumor cells in the brain.

Autoantibodies against NCAM1 from patients with schizophrenia cause schizophrenia-related behavior and changes in synapses in mice.

From genetic and etiological studies, autoimmune mechanisms underlying schizophrenia are suspected; however, the details remain unclear. In this study, we describe autoantibodies against neural cell adhesion molecule (NCAM1) in patients with schizophrenia (5.4%, cell-based assay; 6.7%, ELISA) in a Japanese cohort (n = 223). Anti-NCAM1 autoantibody disrupts both NCAM1-NCAM1 and NCAM1-glial cell line-derived neurotrophic factor (GDNF) interactions. Furthermore, the anti-NCAM1 antibody purified from patients with schizophrenia interrupts NCAM1-Fyn interaction and inhibits phosphorylation of FAK, MEK1, and ERK1 when introduced into the cerebrospinal fluid of mice and also reduces the number of spines and synapses in frontal cortex. In addition, it induces schizophrenia-related behavior in mice, including deficient pre-pulse inhibition and cognitive impairment. In conclusion, anti-NCAM1 autoantibodies in patients with schizophrenia cause schizophrenia-related behavior and changes in synapses in mice. These antibodies may be a potential therapeutic target and serve as a biomarker to distinguish a small but treatable subgroup in heterogeneous patients with schizophrenia.

Prediction and verification of the AD-FTLD common pathomechanism based on dynamic molecular network analysis.

Multiple gene mutations cause familial frontotemporal lobar degeneration (FTLD) while no single gene mutations exists in sporadic FTLD. Various proteins aggregate in variable regions of the brain, leading to multiple pathological and clinical prototypes. The heterogeneity of FTLD could be one of the reasons preventing development of disease-modifying therapy. We newly develop a mathematical method to analyze chronological changes of PPI networks with sequential big data from comprehensive phosphoproteome of four FTLD knock-in (KI) mouse models (PGRNR504X-KI, TDP43N267S-KI, VCPT262A-KI and CHMP2BQ165X-KI mice) together with four transgenic mouse models of Alzheimer's disease (AD) and with APPKM670/671NL-KI mice at multiple time points. The new method reveals the common core pathological network across FTLD and AD, which is shared by mouse models and human postmortem brains. Based on the prediction, we performed therapeutic intervention of the FTLD models, and confirmed amelioration of pathologies and symptoms of four FTLD mouse models by interruption of the core molecule HMGB1, verifying the new mathematical method to predict dynamic molecular networks.

Role of the Drosophila YATA protein in the proper subcellular localization of COPI revealed by in vivo analysis.

yata mutants of Drosophila melanogaster exhibit phenotypes including progressive brain shrinkage, developmental abnormalities and shortened lifespan, whereas in mammals, null mutations of the yata ortholog Scyl1 result in motor neuron degeneration. yata mutation also causes defects in the anterograde intracellular trafficking of a subset of proteins including APPL, which is the Drosophila ortholog of mammalian APP, a causative molecule in Alzheimer's disease. SCYL1 binds and regulates the function of coat protein complex I (COPI) in secretory vesicles. Here, we reveal a role for the Drosophila YATA protein in the proper localization of COPI. Immunohistochemical analyses performed using confocal microscopy and structured illumination microscopy showed that YATA colocalizes with COPI and GM130, a cis-Golgi marker. Analyses using transgenically expressed YATA with a modified N-terminal sequence revealed that the N-terminal portion of YATA is required for the proper subcellular localization of YATA. Analysis using transgenically expressed YATA proteins in which the C-terminal sequence was modified revealed a function for the C-terminal portion of YATA in the subcellular localization of COPI. Notably, when YATA was mislocalized, it also caused the mislocalization of COPI, indicating that YATA plays a role in directing COPI to the proper subcellular site. Moreover, when both YATA and COPI were mislocalized, the staining pattern of GM130 revealed Golgi with abnormal elongated shapes. Thus, our in vivo data indicate that YATA plays a role in the proper subcellular localization of COPI.