Pekka Kallunki - Academia.edu (original) (raw)

Papers by Pekka Kallunki

Human Molecular Genetics, 2021

The authors have provided unedited and high resolution data from gels used in Figure 4A in the ab... more The authors have provided unedited and high resolution data from gels used in Figure 4A in the above mentioned article published in 2009 in Human Molecular Genetics. One of the cropped gels is illustrated for two distinct times of exposure, illustrating the absence of background in controls. These details have been corrected only in this corrigendum/erratum to preserve the published version of record.

The exon-intron structure of the human laminin B2 chain gene was elucidated from genomic X phage ... more The exon-intron structure of the human laminin B2 chain gene was elucidated from genomic X phage clones spanning 2 kilobase pairs (kb) of the 5”flanking region, 58 kb of the structural gene and 10 kb of the 3’flanking region. The entire gene was shown to contain 28 exons. The promoter region has no TATA or CAAT boxes whereas it contains five GC boxes and three AP2-like binding sites. Comparison with the promoter region of the mouse gene revealed six highly conserved sequences of 14 to 42 base pairs in length. Sequencing of the last exon of the gene showed that the 3”untranslated region of the mRNA can be up to 2797 nucleotides with five AATAAA potential polyadenylation signals. The similarity of the human 3”untranslated sequence with that of mouse was shown to be 68.8%. The exonintron structure of the laminin B2 chain gene demonstrated extensive divergence from the human laminin B1 chain gene, which has 34 exons. Only three intron locations are conserved in these two genes. The over...

Journal of Biological Chemistry, 1991

The exon-intron structure of the human laminin B2 chain gene was elucidated from genomic lambda p... more The exon-intron structure of the human laminin B2 chain gene was elucidated from genomic lambda phage clones spanning 2 kilobase pairs (kb) of the 5'-flanking region, 58 kb of the structural gene and 10 kb of the 3'-flanking region. The entire gene was shown to contain 28 exons. The promoter region has no TATA or CAAT boxes whereas it contains five GC boxes and three AP-2-like binding sites. Comparison with the promoter region of the mouse gene revealed six highly conserved sequences of 14 to 42 base pairs in length. Sequencing of the last exon of the gene showed that the 3'-untranslated region of the mRNA can be up to 2797 nucleotides with five AATAAA potential polyadenylation signals. The similarity of the human 3'-untranslated sequence with that of mouse was shown to be 68.8%. The exon-intron structure of the laminin B2 chain gene demonstrated extensive divergence from the human laminin B1 chain gene, which has 34 exons. Only three intron locations are conserved in these two genes. The overall exon profile of the laminin B2 chain gene correlates only marginally with the pattern of structural domains and internal cysteine-rich repeats in the laminin B2 polypeptide chain.

Translational psychiatry, Nov 30, 2017

1q21.1 hemizygous microdeletion is a copy number variant leading to eightfold increased risk of s... more 1q21.1 hemizygous microdeletion is a copy number variant leading to eightfold increased risk of schizophrenia. In order to investigate biological alterations induced by this microdeletion, we generated a novel mouse model (Df(h1q21)/+) and characterized it in a broad test battery focusing on schizophrenia-related assays. Df(h1q21)/+ mice displayed increased hyperactivity in response to amphetamine challenge and increased sensitivity to the disruptive effects of amphetamine and phencyclidine hydrochloride (PCP) on prepulse inhibition. Probing of the direct dopamine (DA) pathway using the DA D1 receptor agonist SKF-81297 revealed no differences in induced locomotor activity compared to wild-type mice, but Df(h1q21)/+ mice showed increased sensitivity to the DA D2 receptor agonist quinpirole and the D1/D2 agonist apomorphine. Electrophysiological characterization of DA neuron firing in the ventral tegmental area revealed more spontaneously active DA neurons and increased firing variabi...

Biophysical Chemistry, 2017

The 140-residue natively disordered protein α-synuclein (aSN) is a central component in the devel... more The 140-residue natively disordered protein α-synuclein (aSN) is a central component in the development of a family of neurodegenerative diseases termed synucleinopathies. This is attributed to its ability to form cytotoxic aggregates such as oligomers and amyloid fibrils. Consequently there have been intense efforts to avoid aggregation or reroute the aggregation pathway using pharmaceutical agents such as small molecules, chaperones and antibodies. aSN's lack of persistent structure in the monomeric state, as well as the multitude of different oligomeric and even different fibrillar states, makes it difficult to raise antibodies that would be efficacious in neutralizing all conformations of aSN. However, the C-terminal 20-40 residues of aSN are a promising epitope for antibody development. It is primarily disordered in both monomeric and aggregated forms, and an anti-C-terminal antibody will therefore be able to bind all forms. Furthermore, it might not interfere with the folding of aSN into membranes, which could be important for its physiological role. Here we report a screen of a series of monoclonal antibodies, which all target the C-terminal of aSN. According to dot blot analyses, different antibodies bound different forms of aSN with different preferences and showed reduced binding to monomeric compared to aggregated (oligomeric and fibrillary) aSN. Consequently they have different effects on aSN's ability to fibrillate and permeabilize membranes. Generally, the antibodies with strongest binding to aggregated aSN in dot blot, also inhibited fibrillation and membrane permeabilization the most, and promoted formation of amorphous aggregates surrounded by small and thin fibers. This suggests that the development of antibodies that targets the C-terminus, exposed in the aggregated forms of aSN, may be beneficial for improved immunotherapy against PD.

Journal of psychiatry & neuroscience : JPN, Jan 7, 2016

The hemizygous 22q11.2 microdeletion is a common copy number variant in humans. The deletion conf... more The hemizygous 22q11.2 microdeletion is a common copy number variant in humans. The deletion confers high risk for neurodevelopmental disorders, including autism and schizophrenia. Up to 41% of deletion carriers experience psychotic symptoms. We present a new mouse model (Df(h22q11)/+) of the deletion syndrome (22q11.2DS) and report on, to our knowledge, the most comprehensive study undertaken to date in 22q11.2DS models. The study was conducted in male mice. We found elevated postpubertal N-methyl-d-aspartate (NMDA) receptor antagonist-induced hyperlocomotion, age-independent prepulse inhibition (PPI) deficits and increased acoustic startle response (ASR). The PPI deficit and increased ASR were resistant to antipsychotic treatment. The PPI deficit was not a consequence of impaired hearing measured by auditory brain stem responses. The Df(h22q11)/+ mice also displayed increased amplitude of loudness-dependent auditory evoked potentials. Prefrontal cortex and dorsal striatal elevatio...

PLoS ONE, 2013

Impaired olfaction is an early pre-motor symptom of Parkinson's disease. The neuropathology under... more Impaired olfaction is an early pre-motor symptom of Parkinson's disease. The neuropathology underlying olfactory dysfunction in Parkinson's disease is unknown, however a-synuclein accumulation/aggregation and altered neurogenesis might play a role. We characterized olfactory deficits in a transgenic mouse model of Parkinson's disease expressing human wild-type a-synuclein under the control of the mouse a-synuclein promoter. Preliminary clinical observations suggest that rasagiline, a monoamine oxidase-B inhibitor, improves olfaction in Parkinson's disease. We therefore examined whether rasagiline ameliorates olfactory deficits in this Parkinson's disease model and investigated the role of olfactory bulb neurogenesis. a-Synuclein mice were progressively impaired in their ability to detect odors, to discriminate between odors, and exhibited alterations in short-term olfactory memory. Rasagiline treatment rescued odor detection and odor discrimination abilities. However, rasagiline did not affect short-term olfactory memory. Finally, olfactory changes were not coupled to alterations in olfactory bulb neurogenesis. We conclude that rasagiline reverses select olfactory deficits in a transgenic mouse model of Parkinson's disease. The findings correlate with preliminary clinical observations suggesting that rasagiline ameliorates olfactory deficits in Parkinson's disease.

Methods and compositions are provided for protecting or enhancing a responsive cell, tissue, orga... more Methods and compositions are provided for protecting or enhancing a responsive cell, tissue, organ or body part function or viability in vivo, insitu or ex vivo in mammals, including human beings, by systemic or local administration of an erythropoietin receptor activity modulator, such as an recombinant tissue protective cytokine.

Xenobiotica, 2014

1. Regulation of hepatic metabolism or transport may lead to increase in drug clearance and compr... more 1. Regulation of hepatic metabolism or transport may lead to increase in drug clearance and compromise efficacy or safety. In this study, cryopreserved human hepatocytes were used to assess the effect of 309 compounds on the activity and mRNA expression (using qPCR techniques) of CYP1A2, CYP2B6 and CYP3A4, as well as mRNA expression of six hepatic transport proteins: OATP1B1 (SCLO1B1), OCT1 (SLC22A1), MDR1 (ABCB1), MRP2 (ABCC2), MRP3 (ABCC3) and BCRP (ABCG2). 2. The results showed that 6% of compounds induced CYP1A2 activity (1.5-fold increase); 30% induced CYP2B6 while 23% induced CYP3A4. qPCR data identified 16, 33 or 32% inducers of CYP1A2, CYP2B6 or CYP3A4, respectively. MRP2 was induced by 27 compounds followed by MDR1 (16)>BCRP (9)>OCT1 (8)>OATP1B1 (5)>MRP3 (2). 3. CYP3A4 appeared to be down-regulated (≥2-fold decrease in mRNA expression) by 53 compounds, 10 for CYP2B6, 6 for OCT1, 4 for BCRP, 2 for CYP1A2 and OATP1B1 and 1 for MDR1 and MRP2. 4. Structure-activity relationship analysis showed that CYP2B6 and CYP3A4 inducers are bulky lipophilic molecules with a higher number of heavy atoms and a lower number of hydrogen bond donors. Finally, a strategy for testing CYP inducers in drug discovery is proposed.

Journal of Cell Biology, 1992

The primary structure of the large human basement membrane heparan sulfate proteoglycan (HSPG) co... more The primary structure of the large human basement membrane heparan sulfate proteoglycan (HSPG) core protein was determined from cDNA clones. The cDNA sequence codes for a 467-kD protein with a 21-residue signal peptide. Analysis of the amino acid sequence showed that the protein consists of five domains. The amino-terminal domain I contains three putative heparan sulfate attachment sites; domain II has four LDL receptor-like repeats; domain III contains repeats similar to those in the short arms of laminin; domain IV has lg-like repeats resembling those in neural cell adhesion molecules; and domain V contains sequences resembling repeats in the G domain of the laminin A chain and repeats in the EGF. The domain structure of the human basement membrane HSPG core protein suggests that this mosaic protein has evolved through shuffling of at least four different functional elements previously identified in other proteins and through duplication of these elements to form the functional do...

Psychopharmacology, 2011

Rationale Psychosis susceptibility is mediated in part by the dopaminergic neurotransmitter syste... more Rationale Psychosis susceptibility is mediated in part by the dopaminergic neurotransmitter system. In humans, individual differences in vulnerability for psychosis are reflected in differential sensitivity for psychostimulants such as amphetamine. We hypothesize that the same genes and pathways underlying behavioral sensitization in mice are also involved in the vulnerability to psychosis. Objectives The aim of the current study was to investigate which genes and pathways may contribute to behavioral sensitization in different dopaminergic output areas in the mouse brain. Methods We took advantage of the naturally occurring difference in psychostimulant sensitivity in DBA/2 mice and selected animals displaying extremes in behavioral sensitization to amphetamine. Subsequently, the dopamine output areas, prefrontal cortex, nucleus accumbens, and cornu ammonis 1 (CA1) area of the hippocampus, were isolated by laser microdissection and subjected to DNA microarray analysis 1 h after a challenge dose of amphetamine. Results A large number of genes with differential expression between high and low responders were identified, with no overlap between brain regions. Validation of these gene expression changes with real-time quantitative polymerase chain reaction demonstrated that the most robust and reproducible effects on gene expression were in the CA1 region of the hippocampus. Interestingly, many of the validated genes in CA1 are members of the cAMP response element (CRE) family and targets of the glucocorticoid receptor (GR) and myocyte enhancer factor 2 (Mef2) transcription factors. Conclusion We hypothesize that CRE, Mef2, and GR signaling form a transcription regulating network, which underlies differential amphetamine sensitivity, and therefore, may play an important role in susceptibility to psychosis.

Psychiatric Genetics, 2010

Linkage and association studies of bipolar affective disorder (BAD) point out chromosome 12q24 as... more Linkage and association studies of bipolar affective disorder (BAD) point out chromosome 12q24 as a region of interest. To investigate this region further, we conducted an association study of 22 DNA markers within a 1.14 Mb region in a Danish sample of 166 patients with BAD and 311 control individuals. Two-hundred and four Danish patients with schizophrenia were also included in the study. We observed highly significant allelic and genotypic association between BAD and two highly correlated markers. The risk allele of both markers considered separately conferred an odds ratio of 2 to an individual carrying one risk allele and an odds ratio of 4 for individuals carrying both risk alleles assuming an additive genetic model. These findings were supported by the haplotype analysis. In addition, we obtained a replication of four markers associated with BAD in an earlier UK study. The most significantly associated marker was also analyzed in a Scottish case-control sample and was earlier associated with BAD in the UK cohort. The association of that particular marker was strongly associated with BAD in a meta-analysis of the Danish, Scottish and UK sample (P=0.0003). The chromosome region confined by our most distant markers is gene-poor and harbours only a few predicted genes. This study implicates the Slynar locus. We confirmed one annotated Slynar transcript and identified a novel transcript in human brain cDNA. This study confirms 12q24.3 as a region of functional importance in the pathogenesis of BAD and highlights the importance of focused genotyping.

Psychiatric Genetics, 2011

Objective An interaction between predisposing genes and environmental stressors is thought to und... more Objective An interaction between predisposing genes and environmental stressors is thought to underlie the neurodevelopmental disorder schizophrenia. In a targeted gene screening, we previously found that the minor allele of the single nucleotide polymorphism (SNP) rs6336 in the neurotrophic tyrosine kinase receptor 1 (NTRK1/TRKA) gene is associated with schizophrenia as a risk factor. Methods We genotyped the TRKA SNP in a total of eight independent Caucasian schizophrenia case-control groups. Result Remarkably, although in five of the groups a higher frequency of the risk allele was indeed found in the patients compared with the controls, in the three other groups the SNP acted as a protective factor. Conclusion An intriguing possibility is that this dual character of the TRKA SNP is caused by its interaction with endophenotypic and/or epistatic factors.

Proceedings of the National Academy of Sciences, 1997

Homeobox genes are regulators of place-dependent morphogenesis and play important roles in contro... more Homeobox genes are regulators of place-dependent morphogenesis and play important roles in controlling the expression patterns of cell adhesion molecules (CAMs). To identify proteins that bind to a regulatory element common to the genes for two neural CAMs, Ng–CAM and L1, we screened a mouse cDNA expression library with a concatamer of the sequence CCATTAGPyGA and found a new homeobox gene, which we have called Barx2 . The homeodomain encoded by Barx2 is 87% identical to that of Barx1 , and both genes are related to genes at the Bar locus of Drosophila melanogaster . Barx1 and Barx2 also encode an identical stretch of 17 residues downstream of the homeobox; otherwise, they share no appreciable homology. In vitro , Barx2 stimulated activity of an L1 promoter construct containing the CCATTAGPyGA motif but repressed activity when this sequence was deleted. Localization studies showed that expression of Barx1 and Barx2 overlap in the nervous system, particularly in the telencephalon, sp...

Proceedings of the National Academy of Sciences, 1999

The cell adhesion molecule L1 regulates axonal guidance and fasciculation during development. We ... more The cell adhesion molecule L1 regulates axonal guidance and fasciculation during development. We previously identified the regulatory region of the L1 gene and showed that it was sufficient for establishing the neural pattern of L1 expression in transgenic mice. In the present study, we characterize a DNA element within this region called the HPD that contains binding motifs for both homeodomain and Pax proteins and responds to signals from bone morphogenetic proteins (BMPs). An ATTA sequence within the core of the HPD was required for binding to the homeodomain protein Barx2 while a separate paired domain recognition motif was necessary for binding to Pax-6. In cellular transfection experiments, L1-luciferase reporter constructs containing the HPD were activated an average of 4-fold by Pax-6 in N2A cells and 5-fold by BMP-2 and BMP-4 in Ng108 cells. Both of these responses were eliminated on deletion of the HPD from L1 constructs. In transgenic mice, deletion of the HPD from an L1-...

Proceedings of the National Academy of Sciences, 1998

The cell adhesion molecule L1 mediates axonal guidance during neural development and mutations in... more The cell adhesion molecule L1 mediates axonal guidance during neural development and mutations in its gene result in severe neurological defects. In previous studies, we identified the promoter for the L1 gene and showed that a neural restrictive silencer element (NRSE) was critical for preventing ectopic expression of L1 during early embryonic development. In the present study, we have investigated the role of the NRSE in the regulation of L1 expression during postnatal development. In gel mobility shift experiments, the NRSE formed DNA–protein complexes with nuclear extracts prepared from the brains of postnatal mice. To examine the influence of the NRSE on postnatal patterns of L1 expression in vivo , we compared the expression of two lacZ transgene constructs, one containing the native L1 gene regulatory sequences (L1lacZ) and another (L1lacZΔN) lacking the NRSE. Newborn mice carrying the L1lacZΔN showed enhanced β-galactosidase expression relative to L1lacZ in the brain and ect...

Neuroscience Letters, 2013

h i g h l i g h t s • We examined the effects of exogenous alpha-synuclein protein on dopamine si... more h i g h l i g h t s • We examined the effects of exogenous alpha-synuclein protein on dopamine signaling. • We injected the protein into mouse brain and studied the effects using amperometry. • The effects depended on the presence of endogenous alpha-synuclein. • Dopamine release and re-uptake rate were decreased six days after injection. • Immediate effects of the injection were opposite but statistically non-significant.

Molecular and Cellular Neuroscience, 2008

LRRK2, α-synuclein, UCH-L1 and DJ-1 are implicated in the etiology of Parkinson's disease. We sho... more LRRK2, α-synuclein, UCH-L1 and DJ-1 are implicated in the etiology of Parkinson's disease. We show for the first time that increase in striatal α-synuclein levels induce increased Lrrk2 mRNA levels while Dj-1 and Uch-L1 are unchanged. We also demonstrate that a mouse strain lacking the dopamine signaling molecule DARPP-32 has significantly reduced levels of both Lrrk2 and α-synuclein, while mice carrying a disabling mutation of the DARPP-32 phosphorylation site T34A or lack α-synuclein do not show any changes. To test if striatal dopamine depletion influences Lrrk2 or α-synuclein expression, we used the neurotoxin 6-hydroxydopamine in rats and MitoPark mice in which there is progressive degeneration of dopamine neurons. Because striatal Lrrk2 and α-synuclein levels were not changed by dopamine depletion, we conclude that Lrrk2 and α-synuclein mRNA levels are possibly co-regulated, but they are not influenced by striatal dopamine levels.

Journal of Clinical Investigation, 2011

Post-mortem analyses of brains from patients with Parkinson disease who received fetal mesencepha... more Post-mortem analyses of brains from patients with Parkinson disease who received fetal mesencephalic transplants show that α-synuclein-containing (α-syn-containing) Lewy bodies gradually appear in grafted neurons. Here, we explored whether intercellular transfer of α-syn from host to graft, followed by seeding of α-syn aggregation in recipient neurons, can contribute to this phenomenon. We assessed α-syn cell-to-cell transfer using microscopy, flow cytometry, and high-content screening in several coculture model systems. Coculturing cells engineered to express either GFP-or DsRed-tagged α-syn resulted in a gradual increase in double-labeled cells. Importantly, α-syn-GFP derived from 1 neuroblastoma cell line localized to red fluorescent aggregates in other cells expressing DsRed-α-syn, suggesting a seeding effect of transmitted α-syn. Extracellular α-syn was taken up by cells through endocytosis and interacted with intracellular α-syn. Next, following intracortical injection of recombinant α-syn in rats, we found neuronal uptake was attenuated by coinjection of an endocytosis inhibitor. Finally, we demonstrated in vivo transfer of α-syn between host cells and grafted dopaminergic neurons in mice overexpressing human α-syn. In summary, intercellularly transferred α-syn interacts with cytoplasmic α-syn and can propagate α-syn pathology. These results suggest that α-syn propagation is a key element in the progression of Parkinson disease pathology. Authorship note: Christian Hansen and Elodie Angot are co-first authors. Jia-Yi Li and Patrik Brundin are co-senior authors.

Human Molecular Genetics, 2021

The authors have provided unedited and high resolution data from gels used in Figure 4A in the ab... more The authors have provided unedited and high resolution data from gels used in Figure 4A in the above mentioned article published in 2009 in Human Molecular Genetics. One of the cropped gels is illustrated for two distinct times of exposure, illustrating the absence of background in controls. These details have been corrected only in this corrigendum/erratum to preserve the published version of record.

The exon-intron structure of the human laminin B2 chain gene was elucidated from genomic X phage ... more The exon-intron structure of the human laminin B2 chain gene was elucidated from genomic X phage clones spanning 2 kilobase pairs (kb) of the 5”flanking region, 58 kb of the structural gene and 10 kb of the 3’flanking region. The entire gene was shown to contain 28 exons. The promoter region has no TATA or CAAT boxes whereas it contains five GC boxes and three AP2-like binding sites. Comparison with the promoter region of the mouse gene revealed six highly conserved sequences of 14 to 42 base pairs in length. Sequencing of the last exon of the gene showed that the 3”untranslated region of the mRNA can be up to 2797 nucleotides with five AATAAA potential polyadenylation signals. The similarity of the human 3”untranslated sequence with that of mouse was shown to be 68.8%. The exonintron structure of the laminin B2 chain gene demonstrated extensive divergence from the human laminin B1 chain gene, which has 34 exons. Only three intron locations are conserved in these two genes. The over...

Journal of Biological Chemistry, 1991

The exon-intron structure of the human laminin B2 chain gene was elucidated from genomic lambda p... more The exon-intron structure of the human laminin B2 chain gene was elucidated from genomic lambda phage clones spanning 2 kilobase pairs (kb) of the 5'-flanking region, 58 kb of the structural gene and 10 kb of the 3'-flanking region. The entire gene was shown to contain 28 exons. The promoter region has no TATA or CAAT boxes whereas it contains five GC boxes and three AP-2-like binding sites. Comparison with the promoter region of the mouse gene revealed six highly conserved sequences of 14 to 42 base pairs in length. Sequencing of the last exon of the gene showed that the 3'-untranslated region of the mRNA can be up to 2797 nucleotides with five AATAAA potential polyadenylation signals. The similarity of the human 3'-untranslated sequence with that of mouse was shown to be 68.8%. The exon-intron structure of the laminin B2 chain gene demonstrated extensive divergence from the human laminin B1 chain gene, which has 34 exons. Only three intron locations are conserved in these two genes. The overall exon profile of the laminin B2 chain gene correlates only marginally with the pattern of structural domains and internal cysteine-rich repeats in the laminin B2 polypeptide chain.

Translational psychiatry, Nov 30, 2017

1q21.1 hemizygous microdeletion is a copy number variant leading to eightfold increased risk of s... more 1q21.1 hemizygous microdeletion is a copy number variant leading to eightfold increased risk of schizophrenia. In order to investigate biological alterations induced by this microdeletion, we generated a novel mouse model (Df(h1q21)/+) and characterized it in a broad test battery focusing on schizophrenia-related assays. Df(h1q21)/+ mice displayed increased hyperactivity in response to amphetamine challenge and increased sensitivity to the disruptive effects of amphetamine and phencyclidine hydrochloride (PCP) on prepulse inhibition. Probing of the direct dopamine (DA) pathway using the DA D1 receptor agonist SKF-81297 revealed no differences in induced locomotor activity compared to wild-type mice, but Df(h1q21)/+ mice showed increased sensitivity to the DA D2 receptor agonist quinpirole and the D1/D2 agonist apomorphine. Electrophysiological characterization of DA neuron firing in the ventral tegmental area revealed more spontaneously active DA neurons and increased firing variabi...

Biophysical Chemistry, 2017

The 140-residue natively disordered protein α-synuclein (aSN) is a central component in the devel... more The 140-residue natively disordered protein α-synuclein (aSN) is a central component in the development of a family of neurodegenerative diseases termed synucleinopathies. This is attributed to its ability to form cytotoxic aggregates such as oligomers and amyloid fibrils. Consequently there have been intense efforts to avoid aggregation or reroute the aggregation pathway using pharmaceutical agents such as small molecules, chaperones and antibodies. aSN's lack of persistent structure in the monomeric state, as well as the multitude of different oligomeric and even different fibrillar states, makes it difficult to raise antibodies that would be efficacious in neutralizing all conformations of aSN. However, the C-terminal 20-40 residues of aSN are a promising epitope for antibody development. It is primarily disordered in both monomeric and aggregated forms, and an anti-C-terminal antibody will therefore be able to bind all forms. Furthermore, it might not interfere with the folding of aSN into membranes, which could be important for its physiological role. Here we report a screen of a series of monoclonal antibodies, which all target the C-terminal of aSN. According to dot blot analyses, different antibodies bound different forms of aSN with different preferences and showed reduced binding to monomeric compared to aggregated (oligomeric and fibrillary) aSN. Consequently they have different effects on aSN's ability to fibrillate and permeabilize membranes. Generally, the antibodies with strongest binding to aggregated aSN in dot blot, also inhibited fibrillation and membrane permeabilization the most, and promoted formation of amorphous aggregates surrounded by small and thin fibers. This suggests that the development of antibodies that targets the C-terminus, exposed in the aggregated forms of aSN, may be beneficial for improved immunotherapy against PD.

Journal of psychiatry & neuroscience : JPN, Jan 7, 2016

The hemizygous 22q11.2 microdeletion is a common copy number variant in humans. The deletion conf... more The hemizygous 22q11.2 microdeletion is a common copy number variant in humans. The deletion confers high risk for neurodevelopmental disorders, including autism and schizophrenia. Up to 41% of deletion carriers experience psychotic symptoms. We present a new mouse model (Df(h22q11)/+) of the deletion syndrome (22q11.2DS) and report on, to our knowledge, the most comprehensive study undertaken to date in 22q11.2DS models. The study was conducted in male mice. We found elevated postpubertal N-methyl-d-aspartate (NMDA) receptor antagonist-induced hyperlocomotion, age-independent prepulse inhibition (PPI) deficits and increased acoustic startle response (ASR). The PPI deficit and increased ASR were resistant to antipsychotic treatment. The PPI deficit was not a consequence of impaired hearing measured by auditory brain stem responses. The Df(h22q11)/+ mice also displayed increased amplitude of loudness-dependent auditory evoked potentials. Prefrontal cortex and dorsal striatal elevatio...

PLoS ONE, 2013

Impaired olfaction is an early pre-motor symptom of Parkinson's disease. The neuropathology under... more Impaired olfaction is an early pre-motor symptom of Parkinson's disease. The neuropathology underlying olfactory dysfunction in Parkinson's disease is unknown, however a-synuclein accumulation/aggregation and altered neurogenesis might play a role. We characterized olfactory deficits in a transgenic mouse model of Parkinson's disease expressing human wild-type a-synuclein under the control of the mouse a-synuclein promoter. Preliminary clinical observations suggest that rasagiline, a monoamine oxidase-B inhibitor, improves olfaction in Parkinson's disease. We therefore examined whether rasagiline ameliorates olfactory deficits in this Parkinson's disease model and investigated the role of olfactory bulb neurogenesis. a-Synuclein mice were progressively impaired in their ability to detect odors, to discriminate between odors, and exhibited alterations in short-term olfactory memory. Rasagiline treatment rescued odor detection and odor discrimination abilities. However, rasagiline did not affect short-term olfactory memory. Finally, olfactory changes were not coupled to alterations in olfactory bulb neurogenesis. We conclude that rasagiline reverses select olfactory deficits in a transgenic mouse model of Parkinson's disease. The findings correlate with preliminary clinical observations suggesting that rasagiline ameliorates olfactory deficits in Parkinson's disease.

Methods and compositions are provided for protecting or enhancing a responsive cell, tissue, orga... more Methods and compositions are provided for protecting or enhancing a responsive cell, tissue, organ or body part function or viability in vivo, insitu or ex vivo in mammals, including human beings, by systemic or local administration of an erythropoietin receptor activity modulator, such as an recombinant tissue protective cytokine.

Xenobiotica, 2014

1. Regulation of hepatic metabolism or transport may lead to increase in drug clearance and compr... more 1. Regulation of hepatic metabolism or transport may lead to increase in drug clearance and compromise efficacy or safety. In this study, cryopreserved human hepatocytes were used to assess the effect of 309 compounds on the activity and mRNA expression (using qPCR techniques) of CYP1A2, CYP2B6 and CYP3A4, as well as mRNA expression of six hepatic transport proteins: OATP1B1 (SCLO1B1), OCT1 (SLC22A1), MDR1 (ABCB1), MRP2 (ABCC2), MRP3 (ABCC3) and BCRP (ABCG2). 2. The results showed that 6% of compounds induced CYP1A2 activity (1.5-fold increase); 30% induced CYP2B6 while 23% induced CYP3A4. qPCR data identified 16, 33 or 32% inducers of CYP1A2, CYP2B6 or CYP3A4, respectively. MRP2 was induced by 27 compounds followed by MDR1 (16)>BCRP (9)>OCT1 (8)>OATP1B1 (5)>MRP3 (2). 3. CYP3A4 appeared to be down-regulated (≥2-fold decrease in mRNA expression) by 53 compounds, 10 for CYP2B6, 6 for OCT1, 4 for BCRP, 2 for CYP1A2 and OATP1B1 and 1 for MDR1 and MRP2. 4. Structure-activity relationship analysis showed that CYP2B6 and CYP3A4 inducers are bulky lipophilic molecules with a higher number of heavy atoms and a lower number of hydrogen bond donors. Finally, a strategy for testing CYP inducers in drug discovery is proposed.

Journal of Cell Biology, 1992

The primary structure of the large human basement membrane heparan sulfate proteoglycan (HSPG) co... more The primary structure of the large human basement membrane heparan sulfate proteoglycan (HSPG) core protein was determined from cDNA clones. The cDNA sequence codes for a 467-kD protein with a 21-residue signal peptide. Analysis of the amino acid sequence showed that the protein consists of five domains. The amino-terminal domain I contains three putative heparan sulfate attachment sites; domain II has four LDL receptor-like repeats; domain III contains repeats similar to those in the short arms of laminin; domain IV has lg-like repeats resembling those in neural cell adhesion molecules; and domain V contains sequences resembling repeats in the G domain of the laminin A chain and repeats in the EGF. The domain structure of the human basement membrane HSPG core protein suggests that this mosaic protein has evolved through shuffling of at least four different functional elements previously identified in other proteins and through duplication of these elements to form the functional do...

Psychopharmacology, 2011

Rationale Psychosis susceptibility is mediated in part by the dopaminergic neurotransmitter syste... more Rationale Psychosis susceptibility is mediated in part by the dopaminergic neurotransmitter system. In humans, individual differences in vulnerability for psychosis are reflected in differential sensitivity for psychostimulants such as amphetamine. We hypothesize that the same genes and pathways underlying behavioral sensitization in mice are also involved in the vulnerability to psychosis. Objectives The aim of the current study was to investigate which genes and pathways may contribute to behavioral sensitization in different dopaminergic output areas in the mouse brain. Methods We took advantage of the naturally occurring difference in psychostimulant sensitivity in DBA/2 mice and selected animals displaying extremes in behavioral sensitization to amphetamine. Subsequently, the dopamine output areas, prefrontal cortex, nucleus accumbens, and cornu ammonis 1 (CA1) area of the hippocampus, were isolated by laser microdissection and subjected to DNA microarray analysis 1 h after a challenge dose of amphetamine. Results A large number of genes with differential expression between high and low responders were identified, with no overlap between brain regions. Validation of these gene expression changes with real-time quantitative polymerase chain reaction demonstrated that the most robust and reproducible effects on gene expression were in the CA1 region of the hippocampus. Interestingly, many of the validated genes in CA1 are members of the cAMP response element (CRE) family and targets of the glucocorticoid receptor (GR) and myocyte enhancer factor 2 (Mef2) transcription factors. Conclusion We hypothesize that CRE, Mef2, and GR signaling form a transcription regulating network, which underlies differential amphetamine sensitivity, and therefore, may play an important role in susceptibility to psychosis.

Psychiatric Genetics, 2010

Linkage and association studies of bipolar affective disorder (BAD) point out chromosome 12q24 as... more Linkage and association studies of bipolar affective disorder (BAD) point out chromosome 12q24 as a region of interest. To investigate this region further, we conducted an association study of 22 DNA markers within a 1.14 Mb region in a Danish sample of 166 patients with BAD and 311 control individuals. Two-hundred and four Danish patients with schizophrenia were also included in the study. We observed highly significant allelic and genotypic association between BAD and two highly correlated markers. The risk allele of both markers considered separately conferred an odds ratio of 2 to an individual carrying one risk allele and an odds ratio of 4 for individuals carrying both risk alleles assuming an additive genetic model. These findings were supported by the haplotype analysis. In addition, we obtained a replication of four markers associated with BAD in an earlier UK study. The most significantly associated marker was also analyzed in a Scottish case-control sample and was earlier associated with BAD in the UK cohort. The association of that particular marker was strongly associated with BAD in a meta-analysis of the Danish, Scottish and UK sample (P=0.0003). The chromosome region confined by our most distant markers is gene-poor and harbours only a few predicted genes. This study implicates the Slynar locus. We confirmed one annotated Slynar transcript and identified a novel transcript in human brain cDNA. This study confirms 12q24.3 as a region of functional importance in the pathogenesis of BAD and highlights the importance of focused genotyping.

Psychiatric Genetics, 2011

Objective An interaction between predisposing genes and environmental stressors is thought to und... more Objective An interaction between predisposing genes and environmental stressors is thought to underlie the neurodevelopmental disorder schizophrenia. In a targeted gene screening, we previously found that the minor allele of the single nucleotide polymorphism (SNP) rs6336 in the neurotrophic tyrosine kinase receptor 1 (NTRK1/TRKA) gene is associated with schizophrenia as a risk factor. Methods We genotyped the TRKA SNP in a total of eight independent Caucasian schizophrenia case-control groups. Result Remarkably, although in five of the groups a higher frequency of the risk allele was indeed found in the patients compared with the controls, in the three other groups the SNP acted as a protective factor. Conclusion An intriguing possibility is that this dual character of the TRKA SNP is caused by its interaction with endophenotypic and/or epistatic factors.

Proceedings of the National Academy of Sciences, 1997

Homeobox genes are regulators of place-dependent morphogenesis and play important roles in contro... more Homeobox genes are regulators of place-dependent morphogenesis and play important roles in controlling the expression patterns of cell adhesion molecules (CAMs). To identify proteins that bind to a regulatory element common to the genes for two neural CAMs, Ng–CAM and L1, we screened a mouse cDNA expression library with a concatamer of the sequence CCATTAGPyGA and found a new homeobox gene, which we have called Barx2 . The homeodomain encoded by Barx2 is 87% identical to that of Barx1 , and both genes are related to genes at the Bar locus of Drosophila melanogaster . Barx1 and Barx2 also encode an identical stretch of 17 residues downstream of the homeobox; otherwise, they share no appreciable homology. In vitro , Barx2 stimulated activity of an L1 promoter construct containing the CCATTAGPyGA motif but repressed activity when this sequence was deleted. Localization studies showed that expression of Barx1 and Barx2 overlap in the nervous system, particularly in the telencephalon, sp...

Proceedings of the National Academy of Sciences, 1999

The cell adhesion molecule L1 regulates axonal guidance and fasciculation during development. We ... more The cell adhesion molecule L1 regulates axonal guidance and fasciculation during development. We previously identified the regulatory region of the L1 gene and showed that it was sufficient for establishing the neural pattern of L1 expression in transgenic mice. In the present study, we characterize a DNA element within this region called the HPD that contains binding motifs for both homeodomain and Pax proteins and responds to signals from bone morphogenetic proteins (BMPs). An ATTA sequence within the core of the HPD was required for binding to the homeodomain protein Barx2 while a separate paired domain recognition motif was necessary for binding to Pax-6. In cellular transfection experiments, L1-luciferase reporter constructs containing the HPD were activated an average of 4-fold by Pax-6 in N2A cells and 5-fold by BMP-2 and BMP-4 in Ng108 cells. Both of these responses were eliminated on deletion of the HPD from L1 constructs. In transgenic mice, deletion of the HPD from an L1-...

Proceedings of the National Academy of Sciences, 1998

The cell adhesion molecule L1 mediates axonal guidance during neural development and mutations in... more The cell adhesion molecule L1 mediates axonal guidance during neural development and mutations in its gene result in severe neurological defects. In previous studies, we identified the promoter for the L1 gene and showed that a neural restrictive silencer element (NRSE) was critical for preventing ectopic expression of L1 during early embryonic development. In the present study, we have investigated the role of the NRSE in the regulation of L1 expression during postnatal development. In gel mobility shift experiments, the NRSE formed DNA–protein complexes with nuclear extracts prepared from the brains of postnatal mice. To examine the influence of the NRSE on postnatal patterns of L1 expression in vivo , we compared the expression of two lacZ transgene constructs, one containing the native L1 gene regulatory sequences (L1lacZ) and another (L1lacZΔN) lacking the NRSE. Newborn mice carrying the L1lacZΔN showed enhanced β-galactosidase expression relative to L1lacZ in the brain and ect...

Neuroscience Letters, 2013

h i g h l i g h t s • We examined the effects of exogenous alpha-synuclein protein on dopamine si... more h i g h l i g h t s • We examined the effects of exogenous alpha-synuclein protein on dopamine signaling. • We injected the protein into mouse brain and studied the effects using amperometry. • The effects depended on the presence of endogenous alpha-synuclein. • Dopamine release and re-uptake rate were decreased six days after injection. • Immediate effects of the injection were opposite but statistically non-significant.

Molecular and Cellular Neuroscience, 2008

LRRK2, α-synuclein, UCH-L1 and DJ-1 are implicated in the etiology of Parkinson's disease. We sho... more LRRK2, α-synuclein, UCH-L1 and DJ-1 are implicated in the etiology of Parkinson's disease. We show for the first time that increase in striatal α-synuclein levels induce increased Lrrk2 mRNA levels while Dj-1 and Uch-L1 are unchanged. We also demonstrate that a mouse strain lacking the dopamine signaling molecule DARPP-32 has significantly reduced levels of both Lrrk2 and α-synuclein, while mice carrying a disabling mutation of the DARPP-32 phosphorylation site T34A or lack α-synuclein do not show any changes. To test if striatal dopamine depletion influences Lrrk2 or α-synuclein expression, we used the neurotoxin 6-hydroxydopamine in rats and MitoPark mice in which there is progressive degeneration of dopamine neurons. Because striatal Lrrk2 and α-synuclein levels were not changed by dopamine depletion, we conclude that Lrrk2 and α-synuclein mRNA levels are possibly co-regulated, but they are not influenced by striatal dopamine levels.

Journal of Clinical Investigation, 2011

Post-mortem analyses of brains from patients with Parkinson disease who received fetal mesencepha... more Post-mortem analyses of brains from patients with Parkinson disease who received fetal mesencephalic transplants show that α-synuclein-containing (α-syn-containing) Lewy bodies gradually appear in grafted neurons. Here, we explored whether intercellular transfer of α-syn from host to graft, followed by seeding of α-syn aggregation in recipient neurons, can contribute to this phenomenon. We assessed α-syn cell-to-cell transfer using microscopy, flow cytometry, and high-content screening in several coculture model systems. Coculturing cells engineered to express either GFP-or DsRed-tagged α-syn resulted in a gradual increase in double-labeled cells. Importantly, α-syn-GFP derived from 1 neuroblastoma cell line localized to red fluorescent aggregates in other cells expressing DsRed-α-syn, suggesting a seeding effect of transmitted α-syn. Extracellular α-syn was taken up by cells through endocytosis and interacted with intracellular α-syn. Next, following intracortical injection of recombinant α-syn in rats, we found neuronal uptake was attenuated by coinjection of an endocytosis inhibitor. Finally, we demonstrated in vivo transfer of α-syn between host cells and grafted dopaminergic neurons in mice overexpressing human α-syn. In summary, intercellularly transferred α-syn interacts with cytoplasmic α-syn and can propagate α-syn pathology. These results suggest that α-syn propagation is a key element in the progression of Parkinson disease pathology. Authorship note: Christian Hansen and Elodie Angot are co-first authors. Jia-Yi Li and Patrik Brundin are co-senior authors.