| 1. |
- Enarsson, Maria, et al.
(författare)
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Extracellular signal-regulated protein kinase signaling is uncoupled from initial differentiation of central nervous system stem cells to neurons
- 2002
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Ingår i: Molecular Cancer Research. - 1541-7786 .- 1557-3125. ; 1:2, s. 147-154
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge about signaling pathways in response to external signals is needed to understand the regulation of stem cell proliferation and differentiation toward particular cell fates. The Ras/extracellular signal-regulated kinase (ERK) pathway has been suggested to play an essential role in neuronal differentiation. We have examined ERK signaling in the transition from multipotent stem cell to post-mitotic progeny using primary stem cells from the rat embryonic cortex. Fibroblast growth factor-2 (FGF-2) is a stem cell mitogen, whereas platelet-derived growth factor AA (PDGF-AA) expands a pool of committed neuronal precursors from stem cells. When comparing ERK activation by these growth factors, we found that FGF-2 stimulates high and PDGF-AA lower levels of ERK phosphorylation in stem cells. Differentiation was monitored as down-regulation of the bHLH transcription factor mammalian achaete-scute homologue-1 (MASH1). Even in the absence of active ERK, MASH1 became down-regulated and microtubule-associated protein 2-positive cells could form. Thus, ERK activation seems dispensable for the earliest steps of CNS stem cell differentiation.
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| 2. |
- Erlandsson, Anna, et al.
(författare)
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Immature neurons from CNS stem cells proliferate in response toplatelet-derived growth factor
- 2001
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Ingår i: Journal of Neuroscience. - 0270-6474 .- 1529-2401. ; 21:10, s. 3483-3491
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Tidskriftsartikel (refereegranskat)abstract
- Identifying external signals involved in the regulation of neural stem cell proliferation and differentiation is fundamental to the understanding of CNS development. In this study we show that platelet-derived growth factor (PDGF) can act as a mitogen for neural precursor cells. Multipotent stem cells from developing CNS can be maintained in a proliferative state under serum-free conditions in the presence of fibroblast growth factor-2 (FGF2) and induced to differentiate into neurons, astrocytes, and oligodendrocytes on withdrawal of the mitogen. PDGF has been suggested to play a role during the differentiation into neurons. We have investigated the effect of PDGF on cultured stem cells from embryonic rat cortex. The PDGF alpha-receptor is constantly expressed during differentiation of neural stem cells but is phosphorylated only after PDGF-AA treatment. In contrast, the PDGF beta-receptor is hardly detectable in uncommitted cells, but its expression increases during differentiation. We show that PDGF stimulation leads to c-fos induction, 5'-bromo-2'deoxyuridine incorporation, and an increase in the number of immature cells stained with antibodies to neuronal markers. Our findings suggest that PDGF acts as a mitogen in the early phase of stem cell differentiation to expand the pool of immature neurons.
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| 3. |
- Persson, Linn, et al.
(författare)
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Elevated antibody reactivity to measles virus Ncore protein among patients with multiple sclerosis and their healthy siblings with intrathecal oligoclonal immunoglobulin G production
- 2014
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Ingår i: Journal of Clinical Virology. - : Elsevier BV. - 1386-6532. ; 61:1, s. 107-112
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Tidskriftsartikel (refereegranskat)abstract
- Patients with multiple sclerosis (MS) and their healthy siblings with the MS oligoclonal bands (OCB) trait, (a hyperimmune condition in form of two or more CSF enriched OCBs) harbor in cerebrospinal fluid (CSF) and serum elevated immunoglobulin G (IgG) titers against measles crude whole-cell antigen. The underlying mechanism resulting in the increased IgG antibody reactivity to measles remains unclear. The response may represent specific IgG reactivity to measles antigens or unspecific auto-antibodies targeting cellular components in the crude whole virus antigens commonly used in detection assays.
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