Anti-glycan antibodies halt axon regeneration in a model of Guillain Barrè Syndrome axonal neuropathy by inducing microtubule disorganization via RhoA-ROCK-dependent inactivation of CRMP-2

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• 作者：Victoria Rozé ; s Salvador^a ; Florencia Heredia^a ; André ; s Berardo^a ; Anabela Palandri^a ; Jose Wojnacki^a ; Ana L. Vivinetto^a ; Kazim A. Sheikh^c ; Alfredo Caceres^a ; Pablo H.H. Lopez^a ; ^b ; ^{phhlopez@immf.uncor.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：GBS ; Guillain Barrè ; Syndrome ; DRGn ; dorsal root ganglion neurons ; MTs ; microtubules ; DRG ; dorsal root ganglion ; GC ; growth cone ; CRMP-2 ; collapsing response mediator protein 2 ; intraperitoneally ; IP ; IgG ; immunoglobulin G ; tubulin GFP ; green fluorescent protein (GFP)-tagged α-tubulin ; CRMP-2 T555A ; mutant form of CRMP-2 at residue 555 (threonine  ; &rarr ;   ; alanine) ; p75NTR ; low affinity receptor for neurothrophins p75 ; Rho-GDIα ; Rho-GDP dissociation inhibitor α ; ROCK ; Rho-associated
• 刊名：Experimental Neurology
• 出版年：2016
• 出版时间：April 2016
• 年：2016
• 卷：278
• 期：Complete
• 页码：42-53
• 全文大小：3561 K

文摘

Several reports have linked the presence of high titers of anti-Gg Abs with delayed recovery/poor prognosis in GBS. In most cases, failure to recover is associated with halted/deficient axon regeneration. Previous work identified that monoclonal and patient-derived anti-Gg Abs can act as inhibitory factors in an animal model of axon regeneration. Further studies using primary dorsal root ganglion neuron (DRGn) cultures demonstrated that anti-Gg Abs can inhibit neurite outgrowth by targeting gangliosides via activation of the small GTPase RhoA and its associated kinase (ROCK), a signaling pathway common to other established inhibitors of axon regeneration. We aimed to study the molecular basis of the inhibitory effect of anti-Gg abs on neurite outgrowth by dissecting the molecular dynamics of growth cones (GC) cytoskeleton in relation to the spatial–temporal analysis of RhoA activity. We now report that axon growth inhibition in DRGn induced by a well characterized mAb targeting gangliosides GD1a/GT1b involves: i) an early RhoA/ROCK-independent collapse of lamellipodia; ii) a RhoA/ROCK-dependent shrinking of filopodia; and iii) alteration of GC microtubule organization/and presumably dynamics via RhoA/ROCK-dependent phosphorylation of CRMP-2 at threonine 555. Our results also show that mAb 1B7 inhibits peripheral axon regeneration in an animal model via phosphorylation/inactivation of CRMP-2 at threonine 555. Overall, our data may help to explain the molecular mechanisms underlying impaired nerve repair in GBS. Future work should define RhoA-independent pathway/s and effectors regulating actin cytoskeleton, thus providing an opportunity for the design of a successful therapy to guarantee an efficient target reinnervation.