New options for ALS/FTD therapies

A team lead by scientists at Thomas Jefferson University have demonstrated a new opportunity for intervening in ALS/FTD. 

They worked on the hypothesis that aberrant arginine-rich dipeptide repeat (R-DPR) proteins are a key toxicity, aggregating with RNA binding proteins. They demonstrated that it was possible to disrupt the aggregation, though initially at the cost of the function of beneficial liquid-liquid phase separations that occur in stress granules and nucleoli, for example.  Modification of the active protein Kapβ2 to be deficient for the nuclear localisation signal (NLS) enabled them, in vitro, to inhibit R-DPR toxicity without side-effect.

In one demonstration of this, neurones were exposed to combinations of an R-DPR with and without NLS-deficient Kapβ2 in the presence of DRAQ7 as a real-time reporter of toxicity resulting in cell death under the different treatments.  

DRAQ7 again displayed its own ultra-low toxicity over long time-courses (here 18h), enabling such ground-breaking work.

Reference:

Kim, K.M., Girdhar, A., Cicardi, M.E. et al. NLS-binding deficient Kapβ2 reduces neurotoxicity via selective interaction with C9orf72-ALS/FTD dipeptide repeats. Commun Biol 8, 2 (2025).  DOI:10.1038/s42003-024-07412-x

3D platform to study EndMT under shear stress

Endothelial to Mesenchymal Transition (EndMT) is a well-understood in development but not in the adult.  This may be important in development of disease or progression through invasion, as in metastasis.  A laboratory at the University of Binghamton, NY has developed a 3D fluidic device that permits the application of shear stress to endothelial cells to determine if this is a driver of EndMT.

To test this required measurement of major cell compartments, cell boundaries and their cell interactions - for example, tight junctions.  DRAQ5 was used to counterstain the cell nucleus at the end of the shear stress period, and this necessitated permeating the collagen matrix utilised and which was tuned to mimic the stiffness of blood vessels.  Using DRAQ5 and fluorescently-tagged phalloidin it was possible to measure the shape index (SI) and orientation angle (OA) under different shear stress conditions, amongst the measurements undertaken to determine the different states of cells under shear stress. 

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Reference:

Mina, S. G., Wang, W., Cao, Q., Huang, P., Murray, B. T., & Mahler, G. J. (2016). Shear stress magnitude and transforming growth factor-βeta 1 regulate endothelial to mesenchymal transformation in a three-dimensional culture microfluidic device. RSC Advances, 6(88), 85457-85467.