| 1. |
- Berglöf, Elisabet, et al.
(författare)
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Inhibition of proteoglycan synthesis affects neuronal outgrowth and astrocytic migration in organotypic cultures of fetal ventral mesencephalon
- 2008
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Ingår i: Journal of Neuroscience Research. - : Wiley-Blackwell. - 0360-4012 .- 1097-4547. ; 86:1, s. 84-92
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Grafting fetal ventral mesencephalon has been utilized to alleviate the symptoms of Parkinson's disease. One obstacle in using this approach is the limited outgrowth from the transplanted dopamine neurons. Thus, it is important to evaluate factors that promote outgrowth from fetal dopamine neurons. Proteoglycans (PGs) are extracellular matrix molecules that modulate neuritic growth. This study was performed to evaluate the role of PGs in dopamine nerve fiber formation in organotypic slice cultures of fetal ventral mesencephalon. Cultures were treated with the PG synthesis inhibitor methyl-umbelliferyl-beta-D-xyloside (beta-xyloside) and analyzed using antibodies against tyrosine hydroxylase (TH) to visualize dopamine neurons, S100beta to visualize astrocytes, and neurocan to detect PGs. Two growth patterns of TH-positive outgrowth were observed: nerve fibers formed in the presence of astrocytes and nerve fibers formed in the absence of astrocytes. Treatment with beta-xyloside significantly reduced the distance of glial-associated TH-positive nerve fiber outgrowth but did not affect the length of the non-glial-associated nerve fibers. The addition of beta-xyloside shifted the nerve fiber growth pattern from being mostly glial-guided to being non-glial-associated, whereas the total amount of TH protein was not affected. Further, astrocytic migration and proliferation were impaired after beta-xyloside treatment, and levels of non-intact PG increased. beta-Xyloside treatment changed the distribution of neurocan in astrocytes, from being localized in vesicles to being diffusely immunoreactive in the processes. To conclude, inhibition of PG synthesis affects glial-associated TH-positive nerve fiber formation in ventral mesencephalic cultures, which might be an indirect effect of impaired astrocytic migration. (c) 2007 Wiley-Liss, Inc.
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| 2. |
- Cernak, Ibolja, et al.
(författare)
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A novel mouse model of penetrating brain injury.
- 2014
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Ingår i: Frontiers in Neurology. - : Frontiers Media SA. - 1664-2295. ; 5, s. 209-
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Tidskriftsartikel (refereegranskat)abstract
- Penetrating traumatic brain injury (pTBI) has been difficult to model in small laboratory animals, such as rats or mice. Previously, we have established a non-fatal, rat model for pTBI using a modified air-rifle that accelerates a pellet, which hits a small probe that then penetrates the experimental animal's brain. Knockout and transgenic strains of mice offer attractive tools to study biological reactions induced by TBI. Hence, in the present study, we adapted and modified our model to be used with mice. The technical characterization of the impact device included depth and speed of impact, as well as dimensions of the temporary cavity formed in a brain surrogate material after impact. Biologically, we have focused on three distinct levels of severity (mild, moderate, and severe), and characterized the acute phase response to injury in terms of tissue destruction, neural degeneration, and gliosis. Functional outcome was assessed by measuring bodyweight and motor performance on rotarod. The results showed that this model is capable of reproducing major morphological and neurological changes of pTBI; as such, we recommend its utilization in research studies aiming to unravel the biological events underlying injury and regeneration after pTBI.
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| 3. |
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| 4. |
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| 5. |
- Günther, Mattias, et al.
(författare)
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Cox‐2 Regulation Differs Between Sexes in the Secondary Inflammatory Response Following Experimental Penetrating Focal Brain Injury in Rats
- 2014
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Ingår i: Journal of Neurotrauma. ; 31:5, s. A-18
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Traumatic brain injury (TBI) is followed by secondary neuronal degeneration, largely dependent on an inflammatory response. This response is probably gender specific, since females are generally better protected than males in animal models and human epidemiological studies of TBI. The reasons are not fully known. We examined aspects of the inflammatory response following experimental TBI in male and female rats to explore possible gender differences. A penetrating brain injury model was used to produce focal TBI in male (n=10) and female (n=10) rats. After 24 h and 72 h the brains were removed and subjected to immunohistochemical analyses and in situ hybridization. Cox‐2 mRNA was elevated in the perilesional area compared to the un‐injured contralateral side, and significantly higher in males compared to females at 24 h and 72 h (p
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| 6. |
- Günther, Mattias, et al.
(författare)
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Neuroprotective effects of N-acetylcysteine amide on experimental focal penetrating brain injury in rats
- 2014
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Ingår i: Neuroscience Meeting, Washington DC, 2014 Nov 15-21. ; , s. 486.06-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Background The beneficial effects of N-acetylcysteine (NAC) on CNS ischemia and after TBI in animal models are well documented. However, the bioavailability of NAC is very low. N-acetylcysteine Amide (NACA) is a newly modified form of N-acetylcysteine that contains an amide group in place of the carboxyl group of NAC. NACA has more efficient membrane permeation and crosses the blood brain barrier. We examined the effects of NACA in the secondary inflammatory response following focal penetrating TBI in rats. Material and methods Focal penetrating TBI were produced in a total of 24 male Sprague-Dawley rats randomly selected for treatment (n=5), non-treatment (n=5) and sham (n=4). The treated animals were given NACA 300 mg/kg ip after 5 min and in the 24h survival group a bolus of 300 mg/kg ip after 4h. After 2h and 24h the brains were removed, cut in 14 µm coronal sections and subjected to immunohistochemistry, immunofluorescence, Fluoro-Jade and TUNEL analyses. Results NACA treatment decreased neuronal degeneration by Fluoro-Jade at 24h (p
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| 7. |
- Plantman, Stefan
(författare)
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Cell-matrix interactions in neuronal regeneration : focus on integrins and laminins
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The central and peripheral nervous system (CNS and PNS, respectively) differ in their ability to regenerate after injury. This difference has been attributed both to intrinsic differences in the properties of the neurons and to the extracellular environment. Several studies have provided evidence that PNS regeneration is dependent upon the interaction between members of the extracellular protein family known as laminins and their cellular receptors called integrins. Neurons projecting to the PNS such as motoneurons upregulate their expression of integrins after axonal injury. This has been interpreted as a sign of a switch from a transmission mode to a regenerative mode where focus is to regrow the injured axon and reestablish the lost connection with its target. The dorsal root ganglion (DRG) neurons are unique in the sense that they have two branches with different regenerative ability. The peripheral branch conveys information from sensory organs and the central branch projects from the DRG into the spinal cord. The peripheral branch can regenerate after injury, whereas the central branch cannot. We determined that integrin mRNA is upregulated after peripheral, but not central branch injury, indicating that this could partly explain the poor outcome after central branch injury. We also examined the regulation of neuronal integrin expression after a pure CNS injury: axotomy of neurons located in the red nucelus. In doing so, we could not detect similar upregulations as described for sensory or motoneurons. Interestingly, we could se an increase in integrin beta1 after axotomy if the neurotrophic factor NT-3 was administered. The combined results of these experiments give further support to the notion that integrin upregulation is an important feature of neuronal regeneration. Also, the results indicate that integrin production can be manipulated by trophic factors and could therefore constitute a possible way to increase the regenerative ability of CNS neurons. The most abundant laminins in the peripheral nerve are laminin-2 (alpha2beta1gamma1) and laminin-8 (alpha4beta1gamma1). Loss of laminin-2 leads to a hereditary muscular dystrophy, affecting both muscles and peripheral nerves. We examined, for the first time, the phenotype of peripheral nerves of mice deficient for laminin-8. We found that these mice have a pronounced dysmyelinating phenotype with thinner sheaths and bundles of unsorted and unmyelinated axons. Using cell cultures, we found that Schwann cells adhere to laminin-8 via integrin alpha6beta1 and that they grow longer processes on laminin-8 compared to laminin-2 which might explain the inability of Schwann cells to properly sort and ensheath axons in laminin-8 mutant mice. Next, we examined the growth of adult DRG neurons on four laminin isoforms. Growth was extensive on laminin-1 and -10, but very poor on laminin-2 and -8 where addition of nerve growth factor was necessary to achieve substantial growth. By use of function blocking antibodies, we saw that DRG neurons interact with laminin-1 and -2 via integrins alpha7beta and alpha3beta1 and with laminin-8 and -10 via alpha6beta1. Finally, in order for integrins to be functional in neuronal outgrowth, they need to be transported to the tip of the growing neurite. A motorprotein called myosin-X was recently shown to be essential for growth of cellular processes by binding and transporting integrins. We therefore examined the regulation of myosin-X in neurons and found that the mRNA was upregulated in both sensory and motoneurons after axotomy. Reducing protein levels in a motoneuron cell line by use of RNA interference decreased neurite growth on laminin. These results indicate that myosin-X could be important for successful axonal regeneration. In summary, the results presented here show that integrins are upregulated after injury by neurons with a regenerative capability. Also, the interaction between laminins and integrins are of fundamental importance for neurite growth from peripheral neurons and for myelination of the peripheral nerve. Finally, the motor protein myosin-X is upregulated after axonal injury and is essential for integrin-mediated neurite growth.
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| 8. |
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| 9. |
- Plantman, Stefan, et al.
(författare)
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Integrin messenger RNAs in the red nucleus after axotomy and neurotrophic administration.
- 2005
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Ingår i: Neuroreport. - : Ovid Technologies (Wolters Kluwer Health). - 0959-4965. ; 16:7, s. 709-13
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Tidskriftsartikel (refereegranskat)abstract
- Integrins are cell surface receptors known to be important for regeneration in the peripheral nervous system. We have investigated the expression of integrin messenger RNAs in red nucleus neurons of adult rats after axotomy and administration of neurotrophic factors. Using radioactive in situ hybridization, messenger RNA for integrin subunits beta1, alpha3, alpha7 and alphaV could be detected. No change of any alpha subunit could be detected after axotomy. In contrast, a small upregulation of beta1 was detected after lesion. Administration of neurotrophin-3 induced a robust further increase in beta1 messenger RNA levels, whereas brain-derived neurotrophic factor did not. By analogy to the peripheral nervous system, we propose that integrins may be important for a regenerative response in central nervous system neurons.
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| 10. |
- Plantman, Stefan, et al.
(författare)
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Neuronal myosin-X is upregulated after peripheral nerve injury and mediates laminin-induced growth of neurites
- 2013
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Ingår i: Molecular and Cellular Neuroscience. - : Academic Press. - 1044-7431 .- 1095-9327. ; 56, s. 96-101
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Tidskriftsartikel (refereegranskat)abstract
- The successful outcome of peripheral neuronal regeneration is attributed both to the growth permissive milieu and the intrinsic ability of the neuron to initiate appropriate cellular responses such as changes in gene expression and cytoskeletal rearrangements. Even though numerous studies have shown the importance of interactions between the neuron and the extracellular matrix (ECM) in axonal outgrowth, the molecular mechanisms underlying the contact between ECM receptors and the cellular cytoskeleton remain largely unknown. Unconventional myosins constitute an important group of cytoskeletal-associated motor proteins. One member of this family is the recently described myosin-X. This protein interacts with several members of the axon growth-associated ECM receptor family of integrins and could therefore be important in neuronal outgrowth. In this study, using radioactive in situ hybridization, we found that expression of myosin-X mRNA is upregulated in adult rat sensory neurons and spinal motoneurons after peripheral nerve injury, but not after central injury. Thus, myosin-X was upregulated after injuries that can be followed by axonal regeneration. We also found that the protein is localized to neuronal growth cones and that silencing of myosin-X using RNA interference impairs the integrin-mediated growth of neurites on laminin, but has no effect on non-integrin mediated growth on N-cadherin.
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