Magnetic spatiotemporal control of SOS1 coupled nanoparticles for guided neurite growth in dopaminergic single cells

Abstract

The axon regeneration of neurons in the brain can be enhanced by activating intracellular signaling pathways such as those triggered by the membrane-anchored Rat sarcoma (RAS) proto-oncogene. Here we demonstrate the induction of neurite growth by expressing tagged permanently active Harvey-RAS protein or the RAS-activating catalytic domain of the guanine nucleotide exchange factor (SOS1cat), in secondary dopaminergic cells. Due to the tag, the expressed fusion protein is captured by functionalized magnetic nanoparticles in the cytoplasm of the cell. We use magnetic tips for remote translocation of the SOS1cat-loaded magnetic nanoparticles from the cytoplasm towards the inner face of the plasma membrane where the endogenous Harvey-RAS protein is located. Furthermore, we show the magnetic transport of SOS1cat-bound nanoparticles from the cytoplasm into the neurite until they accumulate at its tip on a time scale of minutes. In order to scale-up from single cells, we show the cytoplasmic delivery of the magnetic nanoparticles into large numbers of cells without changing the cellular response to nerve growth factor. These results will serve as an initial step to develop tools for refining cell replacement therapies based on grafted human induced dopaminergic neurons loaded with functionalized magnetic nanoparticles in Parkinson model systems.

Magnetogenetics: remote activation of cellular functions triggered by magnetic switches

“…117 Similarly, using smaller MNPs, this strategy has been exploited to capture in the cytoplasm SOS1, a GEF that can convert inactive RAS-GDP into active RAS-GTP. 121 H-RAS is membraneanchored protein belonging to the RAS family that mediates a signalling cascade related with cell survival, cell division and neurite outgrowth. 122 In this case, 8 nm MNPs were coated with a silica shell and functionalised with an HaloTag ligand through click chemistry.…”

Iron Oxide Nanoparticles in Regenerative Medicine and Tissue Engineering

“…Schöneborn et al and Raudzus et al functionalized IONPs with RAS or SOS proteins, which are involved in the regulation of axonal growth as a strategy for the treatment of Parkinson’s disease (PD) that is accompanied by loss or dysfunction of dopaminergic neurons in the substantia nigra (SN). The magnetic translocation of the functionalized IONPs into the cytoplasm and from the cytoplasm to the neurite tip of human dopaminergic neurons led to the accumulation of endogenous RAS protein and the elongation of the growth cone elongated in the desired direction [ 526 , 527 ]. A promising approach to treat neurological diseases, including Alzheimer’s disease, is the use of MSCs.…”

Conjugation of Oligo-His Peptides to Magnetic γ-Fe2O3@SiO2 Core–Shell Nanoparticles Promotes Their Access to the Cytosol

“…Moreover, the aggregation of the MNPs inside the endosomes has been shown to negatively impact their heating efficiency in magnetic hyperthermia due to dipolar interactions between the MNPs, limiting the development of magnetic hyperthermia-based treatment of cancer . In cellular engineering, MNPs have recently been used to remotely control cellular functions, often referred to as “magnetogenetics”. − This approach is primarily used for the control of extracellular proteins or ion channels due to the difficulties in avoiding the endosomal confinement of MNPs after their cellular uptake. Easy access to intracellular proteins capable of triggering a cascade of signaling events would greatly expand the potential of magnetic nanoparticles for cellular engineering.…”