Abstract
Tau proteins are critical for healthy neuronal function, which depends on (i) robust spatial organization
and stabilization of the microtubules network and (ii) precise transportation of proteins and subcellular
organelles from the soma to distinct neuronal compartments. In its pathological form, Tau is known to
contribute to the propagation of Alzheimer’s disease at the cellular level. Precisely controlling and guiding
the spatial distribution and function of Tau proteins in populations of neurons is a powerful tool, with huge
potential for discovery of a strategy to non-invasively block the progression of Alzheimer’s disease.
Technically this method, however, remains a challenge. In this proposal we will address this challenge
with on-chip arrays of parallelized nanomagnetic force stimulation that can be targeted to the subcellular
scale to manipulate organelles in ten thousand of neurons at a time with an unprecedented level of
precision. In previous studies employing this technique, we have observed that Tau-5 protein distribution
localized within 24 h from one side in rat cortical neurons to the opposing side when subjected to a
subcellular force range of 4.5 pN to 70 pN. The underlying mechanism between forces actuation and
protein transport and the interactions between size, shape, dimension of magnetic structures dominating
nanomagnetic force ranges are poorly understood. A better understanding of mechanism and interaction,
however, is critical for a greater adoption of this tool in the lab and for use in implantable devices. In this
proposal we will first determine how size, shape and dimensions of magnetic elements impact the
magnitude and directionality of nanomagnetic force stimulation at high spatiotemporal precision (SA1).
Second, we will identify the spatiotemporal mechanisms underlying nanomagnetic force control in tau-
centric protein transporting (SA2). It is known that intracellular forces can act either on proteins
associated to ferromagnetic nanoparticles, or on actin filaments, or on the microtubules network. This
results in three possible mechanisms to direct tau-centric proteins towards magnetic elements: (1)
directly through dragging nanoparticles, (2) indirectly through microtubules network dynamics, or (3)
indirectly through actin signaling. Our experiments will reveal or exclude potential mechanism and the
outcome will significantly advance our fundamental understanding of nanomagnetic forces in tau-centric
neuronal cell function.