Cellular Plasticity

Cellular and Genetic Neurobiology

Most cells in our body are sized in the 20-60 µm range, however, neurons possess neurites that extend for centimeters in the central nervous system or up to a meter in peripheral nerves. How these extreme projections deal with proteins and organelles distribution? What are the regulations of this complex axonal transport system? How transport defects impact in neuronal function and lead to disease?

Our lab is devoted to understand the establishment of the polarity, compartmentalization, and the mechanisms of proteins and organelles distribution in axons. We focus on understanding the interplay between cytoskeletal proteins, motor proteins and cargos in the regulation of axonal transport, since unraveling the mechanisms that lead to axonal transport defects will allow a better comprehension of transport related neurodegenerative diseases such as Alzheimer’s or Parkinson’s disease.

Through the design and use of fluorescent cargos using high-resolution live cell imaging microscopy, biochemical techniques and pathological characterization we describe the transport properties of different proteins, vesicles and organelles along the axon. We have developed mouse models and human-derived neuronal models based on the differentiation of human stem cells to study axonal transport properties under normal conditions and in disease.

Currently, we extended our development to include technologies for 3-dimensional cultures of human brain organoids as tools for the study of transport derived pathologies in human neural tissue and in genetic models derived from patient’s iPSC.

Proyects:

Unraveling Tau-dependent functions in cell intrinsic axonal structure and transport regulation to test putative therapeutic strategies:

We propose to analyze different parameters of neuronal function using human differentiated neurons under control conditions or after the induction of either tau imbalances, or tau silencing. We analyze the structure and plasticity of the Axon Initial Segment (AIS) and the axonal transport properties in mature polarized human neurons to build a comprehensive transport model that explain changes in dynamics.

Understanding the role of DYRK1A kinase in transport and the activation of transport related pathological mechanisms

DYRK1A is located in the critical region of chromosome 21, which is triplicated in Down Syndrome. Our working hypothesis is that DYRK1A modulates the axonal transport properties of proteins implicated in AD such as tau, the amyloid precursor protein (APP), and the neuronal survival factor (BDNF). Under this hypothesis we propose that enhanced DYRK1A expression will induce axonal transport defects that exacerbate AD pathology, and DYRK1A inhibition would recover transport dynamics and pathology in human models of disease with increased DYRK1A activity.

Human cerebral organoids models of AD neural tissue to study axonal transport defects and oxidative distress

Through the use of induced pluripotent stem cells (iPSC) from controls and AD patients with the APP Swedish mutation we propose to generate a cerebral human organoid to assess the effect of transport defects in the formation of AD pathologies to test the possibility of correction of abnormal neurodegenerative phenotypes.