Guillain Barre Syndrome-Associated Anti-Glycan Antibodies Alter Growth Cone Tubulin Cytoskeleton Via RhoA/ROCK Pathway from Growing DRGs Neurons

ROZÉS SALVADOR, VICTORIA; HEREDIA, FLORENCIA; WOJNAKI, JOSE; PALANDRI, ANABELA; CACERES, ALFREDO; PABLO HECTOR HORACIO LOPEZ

Congreso; Reunión Anual de la Sociedad Argentina de Investigación en Neurociencias; 2014

immune neuropathies such as Guillain Barré Syndrome (GBS).Clinical studies associate the presence of anti-ganglioside antibodies (anti-Gg abs) with poor recovery in GBS.Passive transfer of mAb (GD1a/GT1b,clone 1B7) or patient-derived anti-Gg Abs in an animal model halts axon regeneration.The aim of this work is to study the molecular bases of axonal regeneration inhibition produced by anti-Gg Abs.Two in vitro models were developed including co-cultures of dorsal root ganglion (DRG) explants with peripheral nerve and culture of primary dissociated DRG neuron (DRGn) where the inhibitory effect of mAb 1B7 was confirmed.Fluorescent-tagged cytoskeleton components were used to study their dynamics at growth cones (GC) by time-lapse video microscopy together with immunofluorescence analysis of microtubules.Studies of 1B7-triggered signaling events included measurement of RhoA GTPasa activity using a FRET-based biosensor and activity of its downstream target Collapsin-Response-Mediator Protein-2 (CRMP-2) by phospho-specific mutants and western blot.1B7-treated explants showed a ganglioside-dependent inhibition of axon regeneration associated with the presence of dysthrophic GC. Also, 1B7 treatment induced a RhoA/ROCK-dependent collapse of tubulin cytoskeleton via inactivation of CRMP-2 at T-555.Overall, our data provide knowledge about the mechanisms determining impaired nerve repair.