Novel Tools towards Magnetic Guidance of Neurite Growth: (I) Guidance of Magnetic Nanoparticles into Neurite Extensions of Induced Human Neurons and In Vitro Functionalization with RAS Regulating Proteins.

Hendrik Schöneborn,Jérome Fresnais,Irmgard D Dietzel,Nils Otten,Christine Ménager,Rolf Heumann,Holm Zaehres,Jean-Michel Siaugue,Aude Michel,Emilie Secret,Fabian Raudzus

doi:10.3390/jfb10030032

Abstract

Parkinson’s disease (PD) is a neurodegenerative disease associated with loss or dysfunction of dopaminergic neurons located in the substantia nigra (SN), and there is no cure available. An emerging new approach for treatment is to transplant human induced dopaminergic neurons directly into the denervated striatal brain target region. Unfortunately, neurons grafted into the substantia nigra are unable to grow axons into the striatum and thus do not allow recovery of the original connectivity. Towards overcoming this general limitation in guided neuronal regeneration, we develop here magnetic nanoparticles functionalized with proteins involved in the regulation of axonal growth. We show covalent binding of constitutive active human rat sarcoma (RAS) proteins or RAS guanine nucleotide exchange factor catalytic domain of son of sevenless (SOS) by fluorescence correlation spectroscopy and multiangle light scattering as well as the characterization of exchange factor activity. Human dopaminergic neurons were differentiated from neural precursor cells and characterized by electrophysiological and immune histochemical methods. Furthermore, we demonstrate magnetic translocation of cytoplasmic γ-Fe2O3@SiO2 core-shell nanoparticles into the neurite extensions of induced human neurons. Altogether, we developed tools towards remote control of directed neurite growth in human dopaminergic neurons. These results may have relevance for future therapeutic approaches of cell replacement therapy in Parkinson’s disease.

Highlights

Neurodegenerative disorders are a major public health issue affecting the worldwide aging population
neural progenitor cells (NPCs) were cultured on Matrigel-coated 12-well cell-culture plates (Nunc, Rochester, New York, NY, USA) in N2B27 medium supplemented with 3 μM CHIR99021 (Axon Medchem, Groningen, The Netherlands), 0.5 μM Smoothened agonist (SAG) (Cayman Chemical, Ann Arbor, MI, USA), and 150 μM Ascorbic Acid (AA; Merck, Darmstadt, Germany) with a medium change every second day
After size sorting of the synthesized nanoparticles, their average diameter, measured by transmission electron microscopy (TEM) images analysis (Figure 1A), was 8.8 nm

Summary

Introduction

Neurodegenerative disorders are a major public health issue affecting the worldwide aging population. Parkinson’s disease (PD) caused by loss and dysfunction of dopaminergic neurons in the substantia nigra of the midbrain is not curable by pharmacological treatment. To this date, symptoms of progressing PD can be retarded mainly by antiparkinsonian medication such as levodopa (L-DOPA) or by deep brain stimulation (DBS) [1]. A major breakthrough was achieved for patient-specific cell replacement therapies based on the findings by Yamanaka et al, who described four transcription factors to reprogram somatic cells to induced pluripotent stem cells (iPSCs) by retroviral transduction [2,3]. New approaches are required to remote control cell fiber growth of surviving transplanted neurons upon their neuronal differentiation in situ [4]

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