Forum Posts

Alan Williams
Sep 21, 2021
In Offspring Biosciences
David Engblom, Monica Ek, Anders Ericsson‐Dahlstrand, Anders Blomqvist The Journal of Comparative Neurology, 2001, Nov 1; 440(4):378 DOI: https://doi.org/10.1002/cne.1391 Abstract Systemic inflammation activates central autonomic circuits, such as neurons in the pontine parabrachial nucleus. This activation may be the result of afferent signaling through the vagus nerve, but it may also depend on central prostaglandin-mediated mechanisms. Recently, we have shown that neurons in the parts of the parabrachial nucleus that are activated by immune challenge express prostaglandin receptors of the EP3 and EP4 subtypes, but it remains to be determined if the prostaglandin receptor-expressing neurons are identical to those that respond to immune stimuli. In the present study, bacterial wall lipopolysaccharide was injected intravenously in adult male rats and the expression of c-fos mRNA and of EP3 and EP4 receptor mRNA was examined with complementary RNA probes labeled with digoxigenin and radioisotopes, respectively. Large numbers of neurons in the external lateral parabrachial subnucleus, a major target of vagal-solitary tract efferents, expressed c-fos mRNA. Quantitative analysis showed that about 60% (range 40%–79%) of these neurons also expressed EP3 receptor mRNA. Conversely, slightly more than 50% (range 48%–63%) of the EP3 receptor-expressing neurons in the same subnucleus coexpressed c-fos mRNA. In contrast, few EP4 receptor-expressing neurons were c-fos positive, with the exception of a small population located in the superior lateral and dorsal lateral subnuclei. These findings show that immune challenge activates central autonomic neurons that could be the target of centrally produced prostaglandin E2, suggesting that synaptic signaling and paracrine mechanisms may interact on these neurons.
Activation of prostanoid EP3 and EP4 receptor mRNA‐expressing neurons in the rat parabrachial nucleus by intravenous injection content media
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Alan Williams
Sep 21, 2021
In Offspring Biosciences
Monica Ek, David Engblom, Sipra Saha, Anders Blomqvist, Per-Johan Jakobsson & Anders Ericsson-Dahlstrand Nature, 2001 March 22; 410, 430-431 (2001) DOI: https://doi.org/10.1038/35068632 Abstract Inflammatory reactions against invaders in the body call upon cytokine molecules that elicit systemic responses, such as fever, fatigue, increased pain sensitivity and appetite loss, mediated by the central nervous system. But how cytokines can induce these effects has been a mystery as they are unlikely to cross the blood–brain barrier1,2,3. Here we show that cerebral vascular cells express components enabling a blood-borne cytokine to stimulate the production of prostaglandin E2, an inflammatory mediator whose small size and lipophilic properties allow it to diffuse into the brain parenchyma. As receptors for this prostaglandin are found on responsive deep neural structures4,5,6, we propose that the activated immune system controls central reactions to peripheral inflammation through a prostaglandin-dependent, cytokine-mediated pathway.
Pathway across the blood–brain barrier content media
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Alan Williams
Sep 21, 2021
In Offspring Biosciences
Dan Sunnemark, Sana Eltayeb, Erik Wallström, Lena Appelsved, Åsa Malmberg, Hans Lassmann, Anders Ericsson-Dahlstrand, Fredrik Piehl, Tomas Olsson Brain Pathol, 2003 Oct;13(4):617-29 DOI: https://doi.org/10.1111/j.1750-3639.2003.tb00490.x Abstract Chemokines are important for the recruitment of immune cells into sites of inflammation. To better understand their functional roles during inflammation we have here studied the in vivo expression of receptors for the chemokines CCL3/CCL5/CCL7 (MIP-1α/RANTES/MCP-3) and CX3CL1 (fractalkine), CCR1 and CX3CR1, respectively, in rat myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis. Combined in situ hybridization and immunohistochemistry demonstrated intensely upregulated CCR1 mRN A expression in early, actively demyelinating plaques, whereas CX3CR1 displayed a more generalized expression pattern. CX3CR1 mRNA expressing cells were identified as microglia on the basis of their cellular morphology and positive GSA/B4 lectin staining. In contrast, CCR1 mRNA was preferentially expressed by ED1+GSA/B4+ macrophages. The notion of differential chemokine receptor expression in microglia and monocyte-derived macrophages was corroborated at the protein level by extraction and flow cytometric sorting of cells infiltrating the spinal cord using gating for the surface markers CD45, ED-2 and CD11b. These observations suggest a differential receptor expression between microglia and monocyte-derived macrophages and that mainly the latter cell type is responsible for active demyelination. This has great relevance for the possibility of therapeutic intervention in demyelinating diseases such as multiple sclerosis, for example by targeting signaling events leading to monocyte recruitment.
Differential expression of chemokine receptors CX3CR1 and CCR1 by microglia and macrophages in myelin-oligodendrocyte-glycoprotein-induced.. content media
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Alan Williams
Sep 21, 2021
In Offspring Biosciences
Bo Franzén, Yang Yang, Dan Sunnemark, Monica Wickman, Jan Ottervald, Madalina Oppermann, Kristian Sandberg Proteomics, 2003 Oct 09; 3(10):1920 DOI: https://doi.org/10.1002/pmic.200300535 Abstract Proteome analysis in the central nervous system area represents a large and important challenge in drug discovery. One major problem is to obtain representative and well characterized tissues of high quality for analysis. We have used brain tissues from normal mice to study the effect of post mortem time (up to 32 h) and temperature (4°C and room temperature) on protein expression patterns. A number of proteins were identified using mass spectrometry and potential markers were localized. One of the proteins identified, dihydropyrimidinase related protein-2 (DRP-2), occurs as multiple spots in two-dimensional electrophoresis gels. The ratio between the truncated form of DRP-2 (fDRP-2) and full length DRP-2 is suggested as an internal control that can be used as a biomarker of post mortem time and post mortem temperature between unrelated brain protein samples. Results of this study may be useful in future efforts to detect disease specific alterations in proteomic studies of human post mortem brain tissues.
Dihydropyrimidinase related protein‐2 as a biomarker for temperature and time dependent post mortem changes in the mouse brain proteome content media
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Alan Williams
Sep 21, 2021
In Offspring Biosciences
David Engblom, Monica Ek, Ingela M Andersson, Sipra Saha, Marie Dahlström, Per-Johan Jakobsson, Anders Ericsson-Dahlstrand, Anders Blomqvist The Journal of Comparative Neurology, 2002, Oct 21; 452(3)205 DOI: https://doi.org/10.1002/cne.10380 Abstract Although central nervous symptoms such as hyperalgesia, fatigue, malaise, and anorexia constitute major problems in the treatment of patients suffering from chronic inflammatory disease, little has been known about the signaling mechanisms by which the brain is activated during such conditions. Here, in an animal model of rheumatoid arthritis, we show that microsomal prostaglandin E-synthase, the inducible terminal isomerase in the prostaglandin E2-synthesizing pathway, is expressed in endothelial cells along the blood-brain barrier and in the parenchyma of the paraventricular hypothalamic nucleus. The endothelial cells but not the paraventricular hypothalamic cells displayed a concomitant induction of cyclooxygenase-2 and expressed interleukin-1 type 1 receptors, which indicates that the induction is due to peripherally released cytokines. In contrast to cyclooxygenase-2, microsomal prostaglandin E synthase had very sparse constitutive expression, suggesting that it could be a target for developing drugs that will carry fewer side effects than the presently available cyclooxygenase inhibitors. These findings, thus, suggest that immune-to-brain communication during chronic inflammatory conditions involves prostaglandin E2-synthesis both along the blood-brain barrier and in the parenchyma of the hypothalamic paraventricular nucleus and point to novel avenues for the treatment of the brain-elicited disease symptoms during these conditions.
Induction of microsomal prostaglandin E synthase in the rat brain endothelium and parenchyma in adjuvant-induced arthritis content media
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Alan Williams
Sep 21, 2021
In Offspring Biosciences
Sana Eltayeb, Dan Sunnemark, Anna-Lena Berg, Gunnar Nordvall, Asa Malmberg, Hans Lassmann, Erik Wallström, Tomas Olsson, Anders Ericsson-Dahlstrand J Neuroimmunol. 2003 Sep; 142(1-2):75-85 DOI: https://doi.org/10.1016/S0165-5728(03)00264-9 Abstract We have studied the role of the chemokine receptor CCR1 during the effector stage of myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis in DA rats. In situ hybridization histochemistry revealed local production of the CCR1 ligands CCL3 (MIP-1α) and CCL5 (RANTES), as well as large numbers of CCR1 and CCR5 expressing cells within inflammatory brain lesions. A low-molecular weight CCR1 selective antagonist potently abrogated both clinical and histopathological disease signs during a 5-day treatment period, without signs of peripheral immune compromise. Thus, we demonstrate therapeutic targeting of CCR1-dependent leukocyte recruitment to the central nervous system in a multiple sclerosis (MS)-like rat model.
Effector stage CC chemokine receptor-1 selective antagonism reduces multiple sclerosis-like rat disease content media
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Alan Williams
Sep 21, 2021
In Offspring Biosciences
D Engblom, M Ek, A Ericsson-Dahlstrand, A Blomqvist Neuroscience, 2004; 126(4):989-99 DOI: https://doi.org/10.1016/j.neuroscience.2004.03.042 Abstract This study examines the distribution of prostaglandin E2 receptors of subtype EP3 and EP4 among brain stem parabrachial neurons that were characterized with respect to their neuropeptide expression. By using a dual-labeling in situ hybridization method, we show that preprodynorphin mRNA expressing neurons in the dorsal and central lateral subnuclei express EP3 receptor mRNA. Such receptors are also expressed in preproenkephalin, calcitonin gene related peptide and preprotachykinin mRNA positive neurons in the external lateral subnucleus, whereas preprodynorphin mRNA expressing neurons in this subnucleus are EP receptor negative. In addition, EP3 receptor expression is seen among some enkephalinergic neurons in the Kölliker-Fuse nucleus. Neurons in the central part of the cholecystokininergic population in the regions of the superior lateral subnucleus express EP4 receptor mRNA, whereas those located more peripherally express EP3 receptors. Taken together with previous findings showing that discrete peptidergic cell groups mediate nociceptive and/or visceral afferent information to distinct brain stem and forebrain regions, the present results suggest that the processing of this information in the parabrachial nucleus is influenced by prostaglandin E2. Recent work has shown that prostaglandin E2 is released into the brain following peripheral immune challenge; hence, the parabrachial nucleus may be a region where humoral signaling of peripheral inflammatory events may interact with neuronal signaling elicited by the same peripheral processes.
EP3 and EP4 receptor mRNA expression in peptidergic cell groups of the rat parabrachial nucleus content media
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Alan Williams
Sep 21, 2021
In Offspring Biosciences
Dan Sunnemark, Sana Eltayeb, Maria Nilsson, Erik Wallström, Hans Lassmann, Tomas Olsson, Anna-Lena Berg and Anders Ericsson-Dahlstrand Journal of Neuroinflammation, 2005 July 19; 2:17 DOI: https://doi.org/10.1186/1742-2094-2-17 Abstract Background Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS). It is associated with local activation of microglia and astroglia, infiltration of activated macrophages and T cells, active degradation of myelin and damage to axons and neurons. The proposed role for CX3CL1 (fractalkine) in the control of microglia activation and leukocyte infiltration places this chemokine and its receptor CX3CR1 in a potentially strategic position to control key aspects in the pathological events that are associated with development of brain lesions in MS. In this study, we examine this hypothesis by analyzing the distribution, kinetics, regulation and cellular origin of CX3CL1 and CX3CR1 mRNA expression in the CNS of rats with an experimentally induced MS-like disease, myelin oligodendrocyte glycoprotein (MOG)-induced autoimmune encephalomyelitis (EAE). Methods The expression of CX3CL1 and its receptor CX3CR1 was studied with in situ hybridization histochemical detection of their mRNA with radio labeled cRNA probes in combination with immunohistochemical staining of phenotypic cell markers. Both healthy rat brains and brains from rats with MOG EAE were analyzed. In defined lesional stages of MOG EAE, the number of CX3CR1 mRNA-expressing cells and the intensity of the in situ hybridization signal were determined by image analysis. Data were statistically evaluated by ANOVA, followed by Tukey\primes multiple comparison test. Results Expression of CX3CL1 mRNA was present within neuronal-like cells located throughout the neuraxis of the healthy rat. Expression of CX3CL1 remained unaltered in the CNS of rats with MOG-induced EAE, with the exception of an induced expression in astrocytes within inflammatory lesions. Notably, the brain vasculature of healthy and encephalitic animals did not exhibit signs of CX3CL1 mRNA expression. The receptor, CX3CR1, was expressed by microglial cells in all regions of the healthy brain. Induction of MOG-induced EAE was associated with a distinct accumulation of CX3CR1 mRNA expressing cells within the inflammatory brain lesions, the great majority of which stained positive for markers of the microglia-macrophage lineage. Analysis in time-staged brain lesions revealed elevated levels of CX3CR1 mRNA in microglia in the periplaque zone, as well as a dramatically enhanced accumulation of CX3CR1 expressing cells within the early-active, late-active and inactive, demyelinated lesions. Conclusion Our data demonstrate constitutive and regulated expression of the chemokine CX3CL1 and its receptor CX3CR1 by neurons/astrocytes and microglia, respectively, within the normal and inflamed rat brain. Our findings propose a mechanism by which neurons and reactive astrocytes may control migration and function of the surrounding microglia. In addition, the accumulation of CX3CR1 expressing cells other than microglia within the inflammatory brain lesions indicate a possible role for CX3CL1 in controlling invasion of peripheral leucocytes to the brain.
CX3CL1 (fractalkine) and CX3CR1 expression in myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis content media
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Alan Williams
Sep 21, 2021
In Offspring Biosciences
Anne Morinville, Bengt Fundin, Luc Meury, Anders Juréus, Kristian Sandberg, Johannes Krupp, Sultan Ahmad, Dajan O'Donnell J Comp Neurol. 2007 Oct 20;504(6):680-9 DOI: https://doi.org/10.1002/cne.21484 Abstract It is generally accepted that the voltage-gated, tetrodotoxin-sensitive sodium channel, NaV1.7, is selectively expressed in peripheral ganglia. However, global deletion in mice of NaV1.7 leads to death shortly after birth (Nassar et al. [2004] Proc. Natl. Acad. Sci. U. S. A. 101:12706–12711), suggesting that this ion channel might be more widely expressed. To understand better the potential physiological function of this ion channel, we examined NaV1.7 expression in the rat by in situ hybridization and immunohistochemistry. As expected, highest mRNA expression levels are found in peripheral ganglia, and the protein is expressed within these ganglion cells and on the projections of these neurons in the central nervous system. Importantly, we found that NaV1.7 is present in discrete rat brain regions, and the unique distribution pattern implies a central involvement in endocrine and autonomic systems as well as analgesia. In addition, NaV1.7 expression was detected in the pituitary and adrenal glands. These results indicate that NaV1.7 is not only involved in the processing of sensory information but also participates in the regulation of autonomic and endocrine systems; more specifically, it could be implicated in such vital functions as fluid homeostasis and cardiovascular control.
Distribution of the voltage-gated sodium channel Na(v)1.7 in the rat: expression in the autonomic and endocrine systems content media
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Alan Williams
Sep 21, 2021
In Offspring Biosciences
Sana Eltayeb, Anna-Lena Berg, Hans Lassmann, Erik Wallström, Maria Nilsson, Tomas Olsson, Anders Ericsson-Dahlstrand and Dan Sunnemark Journal of Neuroinflammation 2007 May 7, 4:14 DOI: https://doi.org/10.1186/1742-2094-4-14 Abstract Background The CC chemokine receptors CCR1, CCR2 and CCR5 are critical for the recruitment of mononuclear phagocytes to the central nervous system (CNS) in multiple sclerosis (MS) and other neuroinflammatory diseases. Mononuclear phagocytes are effector cells capable of phagocytosing myelin and damaging axons. In this study, we characterize the regional, temporal and cellular expression of CCR1, CCR2 and CCR5 mRNA in the spinal cord of rats with myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis (MOG-EAE). While resembling human MS, this animal model allows unique access to CNS-tissue from various time-points of relapsing neuroinflammation and from various lesional stages: early active, late active, and inactive completely demyelinated lesions. Methods The expression of CCR1, CCR2 and CCR5 mRNA was studied with in situ hybridization using radio labelled cRNA probes in combination with immunohistochemical staining for phenotypic cell markers. Spinal cord sections from healthy rats and rats with MOG-EAE (acute phase, remission phase, relapse phase) were analysed. In defined lesion stages, the number of cells expressing CCR1, CCR2 and CCR5 mRNA was determined. Data were statistically analysed by the nonparametric Mann-Whitney U test. Results In MOG-EAE rats, extensive up-regulation of CCR1 and CCR5 mRNA, and moderate up-regulation of CCR2 mRNA, was found in the spinal cord during episodes of active inflammation and demyelination. Double staining with phenotypic cell markers identified the chemokine receptor mRNA-expressing cells as macrophages/microglia. Expression of all three receptors was substantially reduced during clinical remission, coinciding with diminished inflammation and demyelination in the spinal cord. Healthy control rats did not show any detectable expression of CCR1, CCR2 or CCR5 mRNA in the spinal cord. Conclusion Our results demonstrate that the acute and chronic-relapsing phases of MOG-EAE are associated with distinct expression of CCR1, CCR2, and CCR5 mRNA by cells of the macrophage/microglia lineage within the CNS lesions. These data support the notion that CCR1, CCR2 and CCR5 mediate recruitment of both infiltrating macrophages and resident microglia to sites of CNS inflammation. Detailed knowledge of expression patterns is crucial for the understanding of therapeutic modulation and the validation of CCR1, CCR2 and CCR5 as feasible targets for therapeutic intervention in MS.
Temporal expression and cellular origin of CC chemokine receptors CCR1, CCR2 and CCR5 in the central nervous system: insight into mechanisms content media
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Alan Williams
Sep 21, 2021
In Offspring Biosciences
Anders Juréus 1, Britt-Marie Swahn, Johan Sandell, Fredrik Jeppsson, Allan E Johnson, Peter Johnström, Jan A M Neelissen, Dan Sunnemark, Lars Farde, Samuel P S Svensson J Neurochem. 2010 Aug;114(3):784-94. DOI: https://doi.org/10.1111/j.1471-4159.2010.06812.x Abstract Positron emission tomography (PET) radioligands that bind selectively to β-amyloid plaques (Aβ) are promising imaging tools aimed at supporting the diagnosis of Alzheimer’s disease and the evaluation of new drugs aiming to modify amyloid plaque load. For extended clinical use, there is a particular need for PET tracers labeled with fluorine-18, a radionuclide with 110 min half-life allowing for central synthesis followed by wide distribution. The development of fluorinated radioligands is, however, challenging because of the lipophilic nature of aromatic fluorine, rendering fluorinated ligands more prone to have high non-specific white matter binding. We have here developed the new benzofuran-derived radioligand containing fluorine, AZD4694 that shows high affinity for β-amyloid fibrils in vitro (Kd = 2.3 ± 0.3 nM). In cortical sections from human Alzheimer’s disease brain [3H]AZD4694 selectively labeled β-amyloid deposits in gray matter, whereas there was a lower level of non-displaceable binding in plaque devoid white matter. Administration of unlabeled AZD4694 to rat showed that it has a pharmacokinetic profile consistent with good PET radioligands, i.e., it quickly entered and rapidly cleared from normal rat brain tissue. Ex vivo binding data in aged Tg2576 mice after intravenous administration of [3H]AZD4694 showed selective binding to β-amyloid deposits in a reversible manner. In Tg2576 mice, plaque bound [3H]AZD4694 could still be detected 80 min after i.v. administration. Taken together, the preclinical profile of AZD4694 suggests that fluorine-18 labeled AZD4694 may have potential for PET-visualization of cerebral β-amyloid deposits in the living human brain.
Characterization of AZD4694, a novel fluorinated Abeta plaque neuroimaging PET radioligand content media
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Alan Williams
Sep 21, 2021
In Offspring Biosciences
Harald Lund 1, Richard F Cowburn, Elin Gustafsson, Kia Strömberg, Anne Svensson, Leif Dahllund, David Malinowsky, Dan Sunnemark Brain Pathol. 2013 Jul;23(4):378-89. DOI: https://doi.org/10.1111/bpa.12001 Abstract Recent reports have implicated tau-tubulin kinase 1 (TTBK1) in the pathological phospho- rylation of tau that occurs in Alzheimer’s disease (AD). The present study was undertaken to provide an extensive characterization of TTBK1 mRNA and protein expression in human brain from AD cases and non-demented controls so as to better understand the disease relevance of this novel kinase. In situ hybridization and immunohistochemistry revealed abundant expression of TTBK1 in the somatodedritic compartment of cortical and hippocampal neurons of both AD cases and controls. TTBK1 immunoreactivity appeared to vary with the level of phospho-tau stain- ing, and was strong in the somatodendritic compartment of apparently healthy hippocampal neurons as well as in pre-tangle neurons where it co-localized with diffuse phospho-Ser422 tau staining. Ser422 was confirmed as a TTBK1 substrate in vitro, and an antibody towards the site, in addition to labeling AT8-positive neurofibrillary tangles (NFTs), neuritic plaques and neuropil threads, also labeled a small population of neurons that were unla- beled with AT8. These data suggest a role for TTBK1 in pre-tangle formation prior to the formation of fibrillar tau and strengthen the idea that tau is phosphorylated at Ser422 at an early/ intermediate stage in NFT formation.
Tau-tubulin kinase 1 expression, phosphorylation and co-localization with phospho-Ser422 tau in the Alzheimer's disease brain content media
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Alan Williams
Sep 21, 2021
In Offspring Biosciences
Gucci Jijuan Gu, Harald Lund, Di Wu, Andries Blokzijl, Christina Classon, Gabriel von Euler, Ulf Landegren, Dan Sunnemark & Masood Kamali-Moghaddam Neuro Molecular Medicine. 2013 May 12, volume 15, pages458–469(2013) DOI: https://doi.org/10.1007/s12017-013-8232-3 Abstract The microtubule-affinity regulating kinase (MARK) family consists of four highly conserved members that have been implicated in phosphorylation of tau protein, causing formation of neurofibrillary tangles in Alzheimer’s disease (AD). Understanding of roles by individual MARK isoform in phosphorylating tau has been limited due to lack of antibodies selective for each MARK isoform. In this study, we first applied the proximity ligation assay on cells to select antibodies specific for each MARK isoform. In cells, a CagA peptide specifically and significantly inhibited tau phosphorylation at Ser262 mediated by MARK4 but not other MARK isoforms. We then used these antibodies to study expression levels of MARK isoforms and interactions between tau and individual MARK isoforms in postmortem human brains. We found a strong and significant elevation of MARK4 expression and MARK4–tau interactions in AD brains, correlating with the Braak stages of the disease. These results suggest the MARK4–tau interactions are of functional importance in the progression of AD and the results also identify MARK4 as a promising target for AD therapy.
Role of Individual MARK Isoforms in Phosphorylation of Tau at Ser262 in Alzheimer’s Disease content media
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Alan Williams
Sep 21, 2021
In Offspring Biosciences
Gucci Jijuan Gu 1, Di Wu, Harald Lund, Dan Sunnemark, Alexander J Kvist, Roy Milner, Sonia Eckersley, Lars N G Nilsson, Karin Agerman, Ulf Landegren, Masood Kamali-Moghaddam J Alzheimers Dis. 2013 Jan;33(3):699-713 DOI: https://pubmed.ncbi.nlm.nih.gov/23001711/ Abstract The appearance of neurofibrillary tangles (NFT), one of the major hallmarks of Alzheimer's disease (AD), is most likely caused by inappropriate phosphorylation and/or dephosphorylation of tau, eventually leading to the accumulation of NFTs. Enhanced phosphorylation of tau on Ser(262) is detected early in the course of the disease and may have a role in the formation of tangles. Several kinases such as microtubule-affinity regulating kinase (MARK), protein kinase A, calcium calmodulin kinase II, and checkpoint kinase 2 are known to phosphorylate tau on Ser(262) in vitro. In this study, we took advantage of the in situ proximity ligation assay to investigate the role of MARK2, one of the four MARK isoforms, in AD. We demonstrate that MARK2 interacts with tau and phosphorylates tau at Ser(262) in stably transfected NIH/3T3 cells expressing human recombinant tau. Staurosporine, a protein kinase inhibitor, significantly reduced the interaction between MARK2 and tau, and also phosphorylation of tau at Ser(262). Furthermore, we observed elevated interactions between MARK2 and tau in post-mortem human AD brains, compared to samples from non-demented elderly controls. Our results from transfected cells demonstrate a specific interaction between MARK2 and tau, as well as MARK2-dependent phosphorylation of tau at Ser(262). Furthermore, the elevated interactions between MARK2 and tau in AD brain sections suggests that MARK2 may play an important role in early phosphorylation of tau in AD, possibly qualifying as a therapeutic target for intervention to prevent disease progression.
Elevated MARK2-dependent phosphorylation of Tau in Alzheimer's disease content media
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Alan Williams
Sep 21, 2021
In Offspring Biosciences
Anna Ridderstad Wollberg, Anders Ericsson-Dahlstrand, Anders Juréus, Petra Ekerot, Sylvia Simon, Maria Nilsson, Stig-Johan Wiklund, Anna-Lena Berg, Mats Ferm, Dan Sunnemark, and Rolf Johansson PNAS April 8, 2014 111 (14) 5409-5414 DOI: https://doi.org/10.1073/pnas.1316510111 Abstract One hallmark of multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE) is infiltration of leukocytes into the CNS, where chemokines and their receptors play a major mediatory role. CX3CR1 is a chemokine receptor involved in leukocyte adhesion and migration and hence a mediator of immune defense reactions. The role of CX3CR1 in MS and EAE pathogenesis however remains to be fully assessed. Here, we demonstrate CX3CR1 mRNA expression on inflammatory cells within active plaque areas in MS brain autopsies. To test whether blocking CNS infiltration of peripheral leukocytes expressing CX3CR1 would be a suitable treatment strategy for MS, we developed a selective, high-affinity inhibitor of CX3CR1 (AZD8797). The compound is active outside the CNS and AZD8797 treatment in Dark Agouti rats with myelin oligodendrocyte glycoprotein-induced EAE resulted in reduced paralysis, CNS pathology, and incidence of relapses. The compound is effective when starting treatment before onset, as well as after the acute phase. This treatment strategy is mechanistically similar to, but more restricted than, current very late antigen-4–directed approaches that have significant side effects. We suggest that blocking CX3CR1 on leukocytes outside the CNS could be an alternative approach to treat MS.
Pharmacological inhibition of the chemokine receptor CX3CR1 attenuates disease in a chronic-relapsing rat model for multiple sclerosis content media
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Alan Williams
Sep 16, 2021
In Offspring Biosciences
Harald Lund, Elin Gustafsson, Anne Svensson, Maria Nilsson, Margareta Berg, Dan Sunnemark, and Gabriel von Euler Acta Neuropathol Commun. 2014; 2: 22 DOI: https://doi.org/10.1186/2051-5960-2-22 Abstract Background: The progression of Alzheimer’s disease (AD) is associated with an increase of phosphorylated tau in the brain. One of the earliest phosphorylated sites on tau is Ser262 that is preferentially phosphorylated by microtubule affinity regulating kinase (MARK), of which four isoforms exist. Herein we investigated the expression of MARK1-4 in the hippocampus of non-demented elderly (NDE) and AD cases. Results: In situ hybridization revealed a uniform, neuronal distribution of all four isoform mRNAs in NDE and AD. Immunohistochemical analyses using isoform-selective antibodies demonstrated that MARK4 in a phosphorylated form colocalizes with p-tau Ser262 in granulovacuolar degeneration bodies (GVDs) that progressively accumulate in AD. In contrast MARK4 is largely absent in the neuronal cytoplasm. MARK3 was localized to a subset of the GVD-containing neurons and also had a weak general cytoplasmic neuronal staining in both NDE and AD. These results suggest that in AD, phosphorylated MARK3 and MARK4 are sequestered and proteolysed in GVDs. MARK1 and MARK2 were absent in GVDs and exhibited relatively uniform neuronal expressions with no apparent differences between NDE and AD. Conclusion: We found that the phosphorylated and fragmented forms of MARK4 and to some extent MARK3 are present in GVDs in AD, and that this expression is highly correlated with phosphorylation of tau at Ser262. This may represent a cellular defense mechanism to remove activated MARK and p-tau Ser262 from the cytosol, thereby reducing the phosphorylating effect on tau Ser262 that appears to be a critical step for subsequent neurodegeneration. Keywords: Alzheimer’s disease, MARK, Phosphorylation, Granulovacuolar degeneration bodies, Tau
MARK4 and MARK3 associate with early tau phosphorylation in Alzheimer’s disease granulovacuolar degeneration bodies content media
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Alan Williams
Sep 16, 2021
In Offspring Biosciences
Sandra Gellhaar, Dan Sunnemark, Håkan Eriksson, Lars Olson & Dagmar Galter Cell and Tissue Research. 2017 May 02; volume 369, pages 445–454(2017) DOI: https://doi.org/10.1007/s00441-017-2626-8 Abstract Myeloperoxidase (MPO) is a key enzyme in inflammatory and degenerative processes, although conflicting reports have been presented concerning its expression in the brain. We studied the cellular localization of MPO and compared numbers of MPO cells in various brain regions between neurologically healthy individuals and patients with Parkinson’s disease (PD) or Alzheimer’s disease (AD; n = 10–25). We also investigated two rodent PD models. MPO immunoreactivity (ir) was detected in monocytes, perivascular macrophages and amoeboid microglia in the human brain parenchyma, whereas no co-localization with glial fibrillary acidic protein (GFAP) ir was observed. In the midbrain, caudate and putamen, we found a significant increase of MPO-immunoreactive cells in PD compared with control brains, whereas in the cerebellum, no difference was apparent. MPO ir was detected neither in neurons nor in occasional small beta-amyloid-immunoreactive plaques in PD or control cases. In the frontal cortex of AD patients, we found significantly more MPO-immunoreactive cells compared with control cases, together with intense MPO ir in extracellular plaques. In the hippocampus of several AD cases, MPO-like ir was observed in some pyramidal neurons. Neither rapid dopamine depletion in the rat PD model, nor slow degeneration of dopamine neurons in MitoPark mice induced the expression of MPO ir in any brain region. MPO mRNA was not detectable with radioactive in situ hybridization in any human or rodent brain area, although myeloid cells from bone marrow displayed clear MPO signals. Our results indicate significant increases of MPO-immunoreactive cells in brain regions affected by neurodegeneration in PD and AD, supporting investigations of MPO inhibitors in novel treatment strategies.
Myeloperoxidase-immunoreactive cells are significantly increased in brain areas affected by neurodegeneration in Parkinson’s and Alzheimer’s content media
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Alan Williams
Sep 16, 2021
In Offspring Biosciences
Sara F Hansson, Alex-Xianghua Zhou, Paulina Vachet, Jan W Eriksson, Maria J Pereira, Stanko Skrtic, Helen Jongsma Wallin, Anders Ericsson-Dahlstrand, Daniel Karlsson, Andrea Ahnmark, Maria Sörhede Winzell, Maria Chiara Magnone, Pia Davidsson PLoS One. . 2018 Apr 27;13(4):e0196601 DOI: https://doi.org/10.1371/journal.pone.0196601 Abstract Beta cell dysfunction accompanies and drives the progression of type 2 diabetes mellitus (T2D), but there are few clinical biomarkers available to assess islet cell stress in humans. Secretagogin, a protein enriched in pancreatic islets, demonstrates protective effects on beta cell function in animals. However, its potential as a circulating biomarker released from human beta cells and islets has not been studied. In this study primary human islets, beta cells and plasma samples were used to explore secretion and expression of secretagogin in relation to the T2D pathology. Secretagogin was abundantly and specifically expressed and secreted from human islets. Furthermore, T2D patients had an elevated plasma level of secretagogin compared with matched healthy controls, which was confirmed in plasma of diabetic mice transplanted with human islets. Additionally, the plasma secretagogin level of the human cohort had an inverse correlation to clinical assessments of beta cell function. To explore the mechanism of secretagogin release in vitro, human beta cells (EndoC-βH1) were exposed to elevated glucose or cellular stress-inducing agents. Secretagogin was not released in parallel with glucose stimulated insulin release, but was markedly elevated in response to endoplasmic reticulum stressors and cytokines. These findings indicate that secretagogin is a potential novel biomarker, reflecting stress and islet cell dysfunction in T2D patients.
Secretagogin is increased in plasma from type 2 diabetes patients and potentially reflects stress and islet dysfunction content media
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Alan Williams
Sep 16, 2021
In Offspring Biosciences
Patricia Miranda-Azpiazua, Marie Svedberga, Makoto Higuchib, Maiko Onob, Zhisheng Jiaa,Dan Sunnemarkc, Charles S. Elmoree, Magnus Schoua, Andrea Varronea Brain Research, 2020 Sep 14; 1749 (2020) 147131 DOI: https://doi.org/10.1016/j.brainres.2020.147131 Abstract The neuropathological hallmark of Parkinsońs disease, multiple system atrophy and dementia with Lewy bodies is the accumulation of α-synuclein. The development of an imaging biomarker for α-synuclein is an unmet need. To date, no selective α-synuclein imaging agent has been identified, though initial studies suggest that the tau tracer [11C]PBB3 displays some degree of binding to α-synuclein. In this study, a series of compounds derived from the PBB3 scaffold were examined using fluorescence imaging and tissue microarrays (TMAs) derived from brain samples with different proteinopathies. One compound, C05-01, was selected based on its higher fluorescence signal associated with Lewy body aggregates compared with other PBB3 analogues. In vitro binding assays using human brain homogenates and recombinant fibrils indicated that C05-01 had higher affinity for α-synuclein (KD/Ki 25 nM for fibrils, Ki 3.5 nM for brain homogenates) as compared with PBB3 (KD 58 nM). In autoradiography (ARG) studies using fresh frozen human tissue and TMAs, [3H]C05-01 displayed specific binding in cases with α-synuclein pathology. C05-01 is the first PBB3 analogue developed as a potential compound targeting α-synuclein. Despite improved affinity for α-synuclein, C05-01 showed specific binding in AD tissue with Amyloid β and tau pathology, as well as relatively high non-specific and off-target binding. Additional efforts are needed to optimize the pharmacological and physicochemical properties of this series of compounds as ligands for α-synuclein. This study also showed that the construction of TMAs from different proteinopathies provides a tool for evaluation of fluorescent or radiolabelled compounds binding to misfolded proteins.
Identification and in vitro characterization of C05-01, a PBB3 derivative with improved affinity for alpha-synuclein content media
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