| 1. |
- Brinkmalm-Westman, Ann, 1966, et al.
(författare)
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Targeting synaptic pathology with a novel affinity mass spectrometry approach.
- 2014
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Ingår i: Molecular & cellular proteomics : MCP. - 1535-9484. ; 13:10, s. 2584-92
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Tidskriftsartikel (refereegranskat)abstract
- We report a novel strategy for studying synaptic pathology by concurrently measuring levels of four SNARE complex proteins from individual brain tissue samples. This method combines affinity purification and mass spectrometry and can be applied directly for studies of SNARE complex proteins in multiple species or modified to target other key elements in neuronal function. We use the technique to demonstrate altered levels of presynaptic proteins in Alzheimer disease patients and prion-infected mice.
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| 2. |
- Jakobsson, Joel, et al.
(författare)
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Altered Concentrations of Amyloid Precursor Protein Metabolites in the Cerebrospinal Fluid of Patients with Bipolar Disorder
- 2013
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Ingår i: Neuropsychopharmacology. - : Springer Science and Business Media LLC. - 0893-133X .- 1740-634X. ; 38:4, s. 664-672
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Tidskriftsartikel (refereegranskat)abstract
- Bipolar disorder is a psychiatric disorder characterized by recurrent episodes of mania/hypomania and depression. Progressive cognitive dysfunction such as impairments in executive function and verbal memory is common in euthymic bipolar patients. The cerebrospinal fluid has previously been used to study neurodegenerative processes in Alzheimer’s disease, from which changes in three core biomarkers have emerged as indicative of degeneration: amyloid β, total tau, and hyperphosphorylated tau. Here, neurodegeneration in bipolar disorder was investigated by assessing the association between bipolar disorder and cerebrospinal fluid biomarkers for neurodegenerative processes. Cerebrospinal fluid was obtained from 139 bipolar disorder patients and 71 healthy controls. Concentrations of total and phosphorylated tau, amyloid β1-42, amyloid β38/β40/β42, and the soluble forms of amyloid precursor protein were measured in patients vs controls. The concentrations of the soluble forms of amyloid precursor protein were significantly lower in bipolar patients compared with controls. The amyloid β42/amyloid β38 and the amyloid β42/amyloid β40 ratios were higher in bipolar patients than controls. There were no discernible differences in the concentrations of total/phosphorylated tau, amyloid β1-42, or amyloid β38/β40/β42. The concentrations of the biomarkers within the bipolar patient group were further associated with different ongoing medical treatments and diagnostic subgroups. The findings suggest that the amyloid precursor protein metabolism is altered in bipolar disorder. The results may have implications for the understanding of the pathophysiology of bipolar disorder and for the development of treatment strategies. Importantly, there were no signs of an Alzheimer-like neurodegenerative process among bipolar patients.
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| 3. |
- Jakobsson, Joel, et al.
(författare)
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Decreased cerebrospinal fluid secretogranin II concentrations in severe forms of bipolar disorder.
- 2013
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Ingår i: Journal of psychiatry & neuroscience : JPN. - : CMA Joule Inc.. - 1488-2434 .- 1180-4882. ; 38:4
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Tidskriftsartikel (refereegranskat)abstract
- Background: Bipolar disorder is a common psychiatric mood disorder that is defined by recurrent episodes of abnormally elevated mood and depression. Progressive structural brain changes in individuals with bipolar disorder have been suggested to be associated with defects in the secretion of neurotrophic factors. We sought to assess how the regulated secretory pathway in the brain is affected in patients with bipolar disorder by measuring chromogranin B and secretogranin II, which are 2 cerebrospinal fluid (CSF) biological markers for this process. Methods: We measured the concentrations of chromogranin B (peptide 439-451) and secretogranin II (peptide 154-165) in the CSF of patients with well-defined bipolar disorder and healthy controls. The lifetime severity of bipolar disorder was rated using the Clinical Global Impression (CGI) scale. Results: We included 126 patients with bipolar disorder and 71 healthy controls in our analysis. Concentrations of secretogranin II were significantly lower in patients with bipolar disorder type I than in healthy controls. The reduction was most pronounced in patients with high CGI scores (i.e., severe disease). Limitations: The cross-sectional design of the current study limits the ability to pinpoint the causalities behind the observed associations. Conclusion: This study shows that the CSF marker secretogranin II has the potential to act as a biological marker for severe forms of bipolar disorder. Our findings indicate that patients with bipolar disorder possess defects in the regulatory secretory pathway, which may be of relevance to the progressive structural brain changes seen in those with severe forms of the disease.
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| 4. |
- Jakobsson, Joel, et al.
(författare)
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Elevated Concentrations of Neurofilament Light Chain in The Cerebrospinal Fluid of Bipolar Disorder Patients.
- 2014
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Ingår i: Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology. - : Springer Science and Business Media LLC. - 1740-634X. ; 39, s. 2349-2356
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Tidskriftsartikel (refereegranskat)abstract
- Bipolar disorder (BD) is characterized by mood swings between manic and depressive states. The etiology and pathogenesis of BD is unclear, but many of the affected cognitive domains, as well as neuroanatomical abnormalities, resemble symptoms and signs of small vessel disease. In small vessel disease, cerebrospinal fluid (CSF) markers reflecting damages in different cell types and subcellular structures of the brain have been established. Hence, we hypothesized that CSF markers related to small vessel disease may also be applicable as biomarkers for bipolar disorder. To investigate this hypothesis, we sampled CSF from 133 patients with bipolar disorder and 86 healthy controls. The concentrations of neurofilament light chain (NF-L), myelin basic protein (MBP), S100B, and heart-fatty acid binding protein (H-FABP) were measured in CSF and analyzed in relation to diagnosis, clinical characteristics, and ongoing medications. Hereby we found an elevation of the marker of subcortical axonal damage, NF-L, in bipolar subjects. We also identified positive associations between NF-L and treatment with atypical antipsychotics, MBP and lamotrigine, and H-FABP and lithium. These findings indicate axonal damage as an underlying neuropathological component of bipolar disorder, though the clinical value of elevated NF-L remains to be validated in follow-up studies. The associations between current medications and CSF brain injury markers might aid in the understanding of both therapeutic and adverse effects of these drugs.Neuropsychopharmacology accepted article peview online, 03 April 2014; doi:10.1038/npp.2014.81.
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| 5. |
- Jakobsson, Joel
(författare)
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Molecular mechanisms in synaptic vesicle recycling
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Neurons communicate through specialized contacts called synapses, which consist of pre- and postsynaptic compartments separated by a narrow synaptic cleft. The stimulus- dependent rapid influx of calcium ions into the presynaptic compartment induces fusion of neurotransmitter-filled vesicles with the plasma membrane and release of their content into the synaptic cleft. The vesicle membrane then needs to be recycled to avoid disruption of synapse morphology and depletion of synaptic vesicles. Three pathways have been described in the literature: clathrin-mediated endocytosis in which vesicles already the size of synaptic vesicles are retrieved at the periactive zone, bulk endocytosis in which larger pieces of membrane are retrieved, and kiss-and-run in which the vesicle remains intact and forms only a transient fusion pore through which neurotransmitter is released. In this thesis, the molecular mechanisms of synaptic vesicle recycling were studied using acute perturbations in lamprey giant reticulospinal axons. The aim was to clarify three different aspects in the recycling machinery: first – how the clathrin coat assembly is regulated, second – how dynamin-dependent fission is regulated, and third – how the synapse copes with intense activity. Three proteins (epsin, EHD, and syndapin) were cloned in Lampetra fluviatilis using PCR-based methods. Binding partners were identified in pull-down assays and lipid-interacting properties were investigated in liposome sedimentation, tubulation, and budding assays. The cloned proteins were further used in the immunization of rabbits for the generation of domain-specific antibodies. These antibodies were used for Western blot, immunoprecipitations, immunolocalization, and presynaptic microinjections. Microinjection experiments were mainly analyzed with electron microscopy to reveal morphological phenotypes. All three proteins cloned in this thesis showed a high degree of homology in protein and lipid interacting regions with their mammalian orthologs as well as similar biochemical properties. The proteins were all localized to the pre-synaptic compartment where they were shown to accumulate at specific regions during synaptic activity: epsin – to the coat of clathrin-coated pits, EHD – to neck regions of GTP S induced endocytic structures, and syndapin – to the peri-active zone (excluding clathrin-coated pits). Perturbation of epsin, EHD, and syndapin in living synapses impaired synaptic vesicle recycling, observed as a loss of synaptic vesicles. Disruption of epsin’s N- terminal region inhibited coat assembly while perturbation of epsin’s clathrin/AP-2- binding domain resulted in abnormal coat assembly. Perturbation of EHD resulted in an accumulation of clathrin coated pits with long necks indicating an impairment of endocytic fission. The perturbation of syndapin was associated with a massive accumulation of membranous cisternae and invaginations, but not of clathrin-coated pits at the plasma membrane. The findings in this thesis suggest that epsin links membrane deformation to clathrin-coated pit formation with a potential role in regulating the size of synaptic vesicles, that EHD regulates dynamin-mediated fission in an ATP-dependent fashion, and that syndapin is required for bulk endocytosis and for stabilizing the plasma membrane during intense synaptic activity. Thus, this thesis has added new knowledge about the molecular network that mediates synaptic vesicle recycling.
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| 6. |
- Jakobsson, Joel, et al.
(författare)
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Regulation of Synaptic Vesicle Budding and Dynamin Function by an EHD ATPase
- 2011
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Ingår i: Journal of Neuroscience. - 0270-6474 .- 1529-2401. ; 31:39, s. 13972-13980
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Tidskriftsartikel (refereegranskat)abstract
- Eps15 homology domain-containing proteins (EHDs) are conserved ATPases implicated in membrane remodeling. Recently, EHD1 was found to be enriched at synaptic release sites, suggesting a possible involvement in the trafficking of synaptic vesicles. We have investigated the role of an EHD1/3 ortholog (1-EHD) in the lamprey giant reticulospinal synapse. 1-EHD was detected by immunogold at endocytic structures adjacent to release sites. In antibody microinjection experiments, perturbation of 1-EHD inhibited synaptic vesicle endocytosis and caused accumulation of clathrin-coated pits with atypical, elongated necks. The necks were covered with helix-like material containing dynamin. To test whether 1-EHD directly interferes with dynamin function, we used fluid-supported bilayers as in vitro assay. We found that 1-EHD strongly inhibited vesicle budding induced by dynamin in the constant presence of GTP. 1-EHD also inhibited dynamin-induced membrane tubulation in the presence of GTP gamma S, a phenomenon linked with dynamin helix assembly. Our in vivo results demonstrate the involvement of 1-EHD in clathrin/dynamin-dependent synaptic vesicle budding. Based on our in vitro observations, we suggest that 1-EHD acts to limit the formation of long, unproductive dynamin helices, thereby promoting vesicle budding.
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| 7. |
- Lautner, Ronald, et al.
(författare)
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Apolipoprotein e genotype and the diagnostic accuracy of cerebrospinal fluid biomarkers for Alzheimer disease.
- 2014
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Ingår i: JAMA psychiatry. - : American Medical Association (AMA). - 2168-6238 .- 2168-622X. ; 71:10, s. 1183-91
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Tidskriftsartikel (refereegranskat)abstract
- Several studies suggest that the apolipoprotein E (APOE) ε4 allele modulates cerebrospinal fluid (CSF) levels of β-amyloid 42 (Aβ42). Whether this effect is secondary to the association of the APOE ε4 allele with cortical Aβ deposition or whether APOE ε4 directly influences CSF levels of Aβ42 independently of Aβ pathology remains unknown.
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| 8. |
- Sandberg, Johan V, et al.
(författare)
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Low neuropeptide Y in cerebrospinal fluid in bipolar patients is associated with previous and prospective suicide attempts.
- 2014
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Ingår i: European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology. - : Elsevier BV. - 1873-7862. ; 24:12, s. 1907-15
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Tidskriftsartikel (refereegranskat)abstract
- The attempted and accomplished suicide rates in patients with bipolar disorder are 40-50% and 15-20%, respectively. No biological markers that help predict suicide been identified. Human and experimental animal data indicate that dysregulation of the neuropeptide Y (NPY) system plays a role in depression, anxiety, and posttraumatic stress disorder (PTSD). The aim of this study was to explore if low cerebrospinal fluid (CSF) NPY is associated with (1) past suicide attempts, (2) future suicide attempts, and (3) trait anxiety. Lumbar puncture was performed on 120 clinically stable patients with bipolar disorder enrolled in the St Göran Bipolar Project, where the number of previous suicide attempts was documented. NPY-like immunoreactivity (NPY-LI) was determined in cerebrospinal fluid (CSF). Patients were reexamined one year after the lumbar puncture and suicide attempts were recorded. NPY-LI was significantly lower in patients with a history of suicide attempt than in patients who had not attempted suicide prior to lumbar puncture. Importantly, NPY-LI was markedly lower in patients who made a suicide attempt during the follow-up period compared to patients who did not. Patients who attempted suicide during the follow-up also had markedly lower NPY-LI than those with previous suicide attempts who did not reattempt. Our results suggest that low CSF NPY-LI predicts future suicide attempts. The data are in line with the hypothesis that NPY signaling is altered in affective disorders and states of emotional dysregulation.
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| 9. |
- Zetterberg, Henrik, 1973, et al.
(författare)
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Blood-cerebrospinal fluid barrier dysfunction in patients with bipolar disorder in relation to antipsychotic treatment
- 2014
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Ingår i: Psychiatry Research. - : Elsevier BV. - 0165-1781 .- 1872-7123. ; 217:3, s. 143-146
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Tidskriftsartikel (refereegranskat)abstract
- Blood-cerebrospinal barrier (BCB) dysfunction has previously been shown in subjects with schizophrenia and depressed patients with attempted suicide. Bipolar disorder (BPD) shares clinical features with both these disorders, but it is unknown if the integrity of the BCB is altered also in BPD. To assess if BCB function in BPD we surveyed 134 mood-stabilized BPD patients and 86 healthy controls. Serum and cerebrospinal fluid (CSF) samples were collected and analyzed for albumin concentration by immunonephelometry. CSF/serum albumin ratio, an established measure of BCB function, was significantly elevated in BPD patients as compared to controls. After stratifying patients according to diagnostic subtype, BPD I patients had the highest CSF/serum albumin ratios. Moreover, BPD patients on antipsychotic treatment had higher CSF/serum albumin ratio than BPD patients on other treatments. When excluding BPD patients on antipsychotic treatment the difference in CSF/serum albumin ratio between the BPD and control groups disappeared. In conclusion, antipsychotic treatment in BPD is associated with elevated CSF/serum albumin ratio, tentatively as a sign of impaired BCB function. Whether this elevation is caused by antipsychotic treatment or is associated with a certain subtype of BPD, requiring antipsychotic treatment, remains to be determined. (C) 2014 Elsevier Ireland 'Ltd. All rights reserved.
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