A synthetic NCAM-derived peptide, FGL, protects hippocampal neurons from ischemic insult both in vitro and in vivo
ABSTRACT There is a major unmet need for development of innovative strategies for neuroprotection against ischemic brain injury. Here we show that FGL, a neural cell adhesion molecule (NCAM)-derived peptide binding to and inducing phosphorylation of the fibroblast growth factor receptor (FGFR), acts neuroprotectively after an ischemic insult both in vitro and in vivo. The neuroprotective activity of FGL was tested in vitro on dissociated rat hippocampal neurons and hippocampal slice cultures, using a protocol of oxygen-glucose deprivation (OGD). FGL protected hippocampal neurons from damage and maintained or restored their metabolic and presynaptic activity, both if employed as a pretreatment alone to OGD, and if only applied after the insult. In vivo 24 h pretreatment with a single suboccipital injection of FGL significantly protected hippocampal CA1 neurons from death in a transient global ischemia model in the gerbil. We conclude that FGL promotes neuronal survival after ischemic brain injury.
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ABSTRACT: The neural cell adhesion molecule (NCAM) plays a role in neurite outgrowth, synaptogenesis, and neuronal differentiation. The NCAM mimetic peptide FG Loop (FGL) promotes neuronal survival in vitro and enhances spatial learning and memory in rats. We here investigated the effects of FGL on neural stem cells (NSC) in vitro and in vivo. In vitro, cell proliferation of primary NSC was assessed after exposure to various concentrations of NCAM or FGL. The differentiation potential of NCAM- or FGL-treated cells was assessed immunocytochemically. To investigate its influence on endogenous NSC in vivo, FGL was injected subcutaneously into adult rats. The effects on NSC mobilization were studied both via non-invasive positron emission tomography (PET) imaging using the tracer [(18)F]-fluoro-L-thymidine ([(18)F]FLT), as well as with immunohistochemistry. Only FGL significantly enhanced NSC proliferation in vitro, with a maximal effect at 10 μg/ml. During differentiation, NCAM promoted neurogenesis, while FGL induced an oligodendroglial phenotype; astrocytic differentiation was neither affected by NCAM or FGL. Those differential effects of NCAM and FGL on differentiation were mediated through different receptors. After FGL-injection in vivo, proliferative activity of NSC in the subventricular zone (SVZ) was increased (compared to placebo-treated animals). Moreover, non-invasive imaging of cell proliferation using [(18)F]FLT-PET supported an FGL-induced mobilization of NSC from both the SVZ and the hippocampus. We conclude that FGL robustly induces NSC mobilization in vitro and in vivo, and supports oligodendroglial differentiation. This capacity renders FGL a promising agent to facilitate remyelinization, which may eventually make FGL a drug candidate for demyelinating neurological disorders.Stem cell reviews 05/2014; 10(4). DOI:10.1007/s12015-014-9512-5 · 3.21 Impact Factor
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ABSTRACT: The neural cell adhesion molecule peptide mimetic fibroblast growth loop (FGL) proved to exert neuroprotective, neurotrophic, and anti-inflammatory effects in different in vitro and in vivo experiments. Based on this beneficial efficacy profile, it is currently in clinical development for neurodegenerative diseases and brain insults. Here, we addressed the hypothesis that the peptide might affect development of seizures in a kindling paradigm, as well as associated behavioral and cellular alterations. Both doses tested, 2 and 10 mg/kg FGL, significantly reduced the number of stimulations necessary to induce a generalized seizure. FGL did not exert relevant effects on the behavioral patterns of kindled animals. As expected, kindling increased the hippocampal cell proliferation rate. Whereas the low dose of FGL did not affect this kindling-associated alteration, 10 mg/kg FGL proved to attenuate the expansion of the doublecortin-positive cell population. These data suggest that FGL administration might have an impact on disease-associated alterations in the hippocampal neuronal progenitor cell population. In conclusion, the effects of the peptide mimetic FGL in the kindling model do not confirm a disease-modifying effect with a beneficial impact on the development or course of epilepsy. The results obtained with FGL rather raise some concern regarding a putative effect, which might promote the formation of a hyperexcitable network. Future studies are required to further assess the risks in models with development of spontaneous seizures.ACS Chemical Neuroscience 01/2014; 5(3). DOI:10.1021/cn400153g · 4.21 Impact Factor
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ABSTRACT: A class of designed self-assembling peptide nanofiber scaffolds has been shown to be a good biomimetic material in tissue engineering. Here, we specifically made a new peptide hydrogel scaffold FGLmx by mixing the pure RADA16 and designer functional peptide RADA16-FGL solution, and we analyzed the physiochemical properties of each peptide with atomic force microscopy (AFM) and circular dichroism (CD). In addition, we examined the biocompatibility and bioactivity of FGLmx as well as RADA16 scaffold on spinal cord-derived neural stem cells (SC-NSCs) isolated from neonatal rats. Our results showed that RADA16-FGL displayed a weaker β-sheet structure and FGLmx could self-assemble into nanofibrous morphology. Moreover, we found that FGLmx was not only noncytotoxic to SC-NSCs but also promoted SC-NSC proliferation and migration into the three-dimensional (3-D) scaffold, meanwhile, the adhesion and lineage differentiation of SC-NSCs on FGLmx were similar to that on RADA16. Our results indicated that the FGL-functionalized peptide scaffold might be very beneficial for tissue engineering and suggested its further application for spinal cord injury (SCI) repair.Materials Science and Engineering C 01/2015; 46:140–147. DOI:10.1016/j.msec.2014.10.019 · 2.74 Impact Factor