The Neurofilament-Derived Peptide NFL-TBS.40-63 Targets Neural Stem Cells and Affects Their Properties
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Cell-Based Drug Development, Screening, and Toxicology CELL-BASED DRUG DEVELOPMENT,SCREENING, AND TOXICOLOGY The Neurofilament-Derived Peptide NFL-TBS.40-63 Targets Neural Stem Cells and Affects Their Properties * * CLAIRE LEPINOUX´ -CHAMBAUD, KRISTELL BARREAU, JOEL¨ EYER Key Words. Neural stem cells x NFL-TBS.40-63 peptide x Targeting x Subventricular zone x Differentiation x Proliferation Laboratoire Neurobiologie ABSTRACT et Transgenese, L’Universite´ Targeting neural stem cells (NSCs) in the adult brain represents a promising approach for developing Nantes, Angers, Le Mans, new regenerative strategies, because these cells can proliferate, self-renew, and differentiate into new Unite´ Propre de Recherche neurons, astrocytes, and oligodendrocytes. Previous work showed that the NFL-TBS.40-63 peptide, de l’Enseignement Superieur´ corresponding to thesequenceof a tubulin-binding site on neurofilaments,can target glioblastomacells, EA-3143, Institut de Biologie where it disrupts their microtubules and inhibits their proliferation. We show that this peptide targets en Sante,´ Universite´ NSCsinvitro and invivo when injected intothe cerebrospinalfluid. Although neurosphere formation was not altered by the peptide, the NSC self-renewal capacity and proliferation were reduced and were d’Angers, Centre Hospitalier associated with increased adhesion and differentiation. These results indicate that the NFL-TBS.40-63 Universitaire, Angers, France peptide represents a new molecular tool to target NSCs to develop new strategies for regenerative med- STEM CELLS TRANSLATIONAL MEDICINE – *Contributed equally. icine and the treatment of brain tumors. 2016;5:901 913 Correspondence: Joel¨ Eyer, Ph.D., Laboratoire Neurobiologie & Transgenese, L’UNAM, UPRES SIGNIFICANCE EA-3143, Institut de Biologie en In the present study, the NFL-TBS.40-63 peptide targeted neural stem cells in vitro when isolated from Sante,´ Universited´ ’Angers, Centre Hospitalier Universitaire, the subventricular zone and in vivo when injected into the cerebrospinal fluid present in the lateral Batimentˆ IBS-IRIS, 49033 Angers, ventricle. The in vitro formation of neurospheres was not altered by the peptide; however, at a high France. Telephone: 02-44-68-84-88. concentration of the peptide, the neural stem cell (NSC) self-renewal capacity and proliferation were E-Mail: [email protected] reduced and associated with increased adhesion and differentiation. These results indicate that the Received August 27, 2015; NFL-TBS.40-63 peptide represents a new molecular tool to target NSCs to develop new strategies for accepted for publication regenerative medicine and the treatment of brain tumors. February 23, 2016; published Online First on May 13, 2016. ©AlphaMed Press INTRODUCTION lesions, and malignant glioma [12, 13]. Several 1066-5099/2016/$20.00/0 studies have also showed the recruitment of http://dx.doi.org/ It is a major challenge to treat chronic diseases of endogenousNSCsinseveralbraindisorders.For in- 10.5966/sctm.2015-0221 the central nervous system, because most active stance, in patients with multiple sclerosis, endog- drugs do not pass the blood-brain barrier efficiently enous mobilization of NSCs from the SVZ to to allow sufficient bioavailability amounts in the striatal lesions was observed [14]. Endogenous mi- brain. Another important issue is to deliver the gration of NSCs to the glioma was also demon- highlybioactive moleculesspecificallyto thedesired strated [15]. A recent review of clinical trials site of action to avoid secondary or toxic effects. reported the use of NSCs as a possible treatment One promising strategy is to inject such molecules of neurodegenerative diseases, including amyo- in the cerebrospinal fluid to target neural stem cells trophic lateral sclerosis, stroke, and spinal cord in- (NSCs). These cells are located in the neurogenic re- jury [16]. Therefore, the capacity to target and gions of the adult brain (subventricular zone [SVZ], manipulate endogenous NSCs represents a promis- dentate gyrus of the hippocampus) and along the ing avenue for regenerative-based therapies to in- central canal of the spinal cord [1–8]. The SVZ rep- crease their mobilization, stimulate neurogenesis, resents the most important pool of endogenous and avoid the occurrence of side effects [17]. NSCs in the brain. They are characterized by their A potential candidate to target NSCs is the capacity to self-renew, form neurospheres in cul- NFL-TBS.40-63 peptide, which corresponds to the ture, proliferate, and differentiate into neurons, as- tubulin-binding site located on the light subunit trocytes, and oligodendrocytes [9–11]. The use of of neurofilaments [18]. The peptide alone, as well normal or genetically modified NSCs has been de- as nanoparticles functionalized with the peptide, scribed for the treatment of neurodegenerative dis- can massively enter glioblastoma cells in vitro orders (Parkinson’s, Huntington’s, and Alzheimer’s and in vivo; however, the uptake is very low in diseases, amyotrophic lateral sclerosis), spinal cord healthy cells (astrocytes and neurons) [19–21]. STEM CELLS TRANSLATIONAL MEDICINE 2016;5:901–913 www.StemCellsTM.com ©AlphaMed Press 2016 902 NFL-TBS.40-63 Peptide Targets Neural Stem Cells Moreover, this peptide disrupts the microtubule network of glio- 20 ng/ml EGF. The cells were incubated in the absence or presence blastoma cells and reduces the tumor volume in animals bearing of increasing concentrations of biotinylated NFL-TBS.40-63 peptide glioma but has no major toxicity on healthy cells. The peptide or with 1 mg/ml colchicine (Sigma-Aldrich). After 5–7 days, the total did not damage the tissue when injected into healthy brain number of primary neurospheres and the percentage of adherent [19–21]. Recent works have also shown that this peptide promotes primary neurospheres were determined in each condition using mi- the differentiation and maturation of oligodendrocytes derived croscope analysis. For the self-renewal assay, primary neurospheres from newborn rats in vitro [22, 23]. were collected in each condition, dissociated into single cells, and In the present study, we investigated the targeting capacity and seeded in media containing 20 ng/ml EGF. After 5 days, the total potential effects of this peptide on NSCs. We show that the peptide is number of secondary neurospheres was counted in each condition able to target NSCs isolated from newborn and adult animals in vitro using microscopeanalysis. The morphologyofprimaryneurospheres and in vivo after its injection into the lateral ventricle of adult rats. was observed with an inverted microscope (Leica DMI6000; Leica Although the peptide showed a cytotoxic effect on the glioblastoma Biosystems, Nussloch, Germany, http://www.leicabiosystems.com) cells, it has no major effect on NSCs at concentrations less than equipped with a CoolSNAP-HQ2 camera and analyzed using 10 mmol/l. At higher concentrations, the peptide affects their self- MetaMorph, version 7.1.7.0, software (Molecular Devices, renewal and proliferation ability and increases their adhesion and dif- Sunnyvale, CA, http://www.moleculardevices.com). They were ferentiation. Together, these results indicate that the NFL-TBS.40-63 also observed using scanning electron microscopy. peptide represents a promising tool for targeting the delivery of bi- ologically active proteins into NSCs and/or manipulating these cells. Flow Cytometry (Fluorescence-Activated Cell Sorting) The uptake of 5-FAM-labeled NFL-TBS.40-63 and NFL-SCR pep- MATERIALS AND METHODS tides was quantified in NSCs derived from newborn and adult rats. Cell Culture and Materials A total of 200–300 neurospheres were seeded in 35-mm dishes and cultured for 30 minutes at 37°C in media containing 5-FAM- Primary cultures of NSCs were derived from the SVZ of newborn labeled peptides. To quench the extracellular signal of the 5-FAM- (1–5days)andadult(,4 months) Wistar rats, as previously de- labeled peptides, 0.4% trypan blue (Sigma-Aldrich) was added scribed [24]. The dissociated cells were grown in minimal essential before analysis. To investigate the uptake molecular mechanism, medium-a (Thermo Fisher Scientific Life Sciences, Waltham, MA, neurospheres were preincubated at 4°C for 30 minutes or with http://www.thermofisher.com) supplemented with 25 mmol/l 10 mmol/l sodium azide in the presence of 6mmol/l 2-deoxy-D-glucose D-glucose (Sigma-Aldrich, St. Louis, MO, http://www.sigmaaldrich. to deplete cellular ATP or with different endocytosis and signaling com), 1 mmol/l sodium pyruvate, 15 mmol/l HEPES, 5% penicillin/ pathway inhibitors for 30 minutes at 37°C, as previously described streptomycin, 1% B27 (Thermo Fisher Scientific Life Sciences), and [21]. Next, 20 mmol/l 5-FAM-labeled NFL-TBS.40-63 peptide was 20 ng/ml epidermal growth factor (EGF; Promega, Madison, WI, added to the cells for 30 minutes at 37C°. Subsequently, after centri- http://www.promega.com). After 5–7 days, the stem cells formed fugation (5 minutes at 42g), the cells were dissociated mechanically floating neurospheres. andwashedtwicewithPBSandthenresuspendedin50mg/ml propi- The NFL-TBS.40-63 peptide (YSSYSAPVSSSLSVRRSYSSSSGS) is dium iodide (PI; Sigma-Aldrich). The fluorescent-positive viable cells biotinylated or coupled to 5-carboxyfluorescein (5-FAM) and was that incorporated the 5-FAM-labeled peptide were analyzed by flow synthesized by Millegen (Toulouse, France), Eurogentec (Seraing, cytometry (FACSCalibur; Becton Dickinson, Franklin Lakes, NJ, http:// Belgium, http://www.eurogentec.com),