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Acta Neuropathologica

, Volume 128, Issue 6, pp 835–852

First Online: 24 October 2014Received: 09 July 2014Revised: 29 September 2014Accepted: 29 September 2014

Abstract

Paraneoplastic cerebellar degeneration PCD is characterized by loss of Purkinje cells PCs associated with progressive pancerebellar dysfunction in the presence of onconeural Yo antibodies. These antibodies recognize the cerebellar degeneration-related antigens CDR2 and CDR2L. Response to PCD therapy is disappointing due to limited understanding of the neuropathological mechanisms. Here, we report the pathological role of CDR antibodies on the calcium homeostasis in PCs. We developed an antibody-mediated PCD model based on co-incubation of cerebellar organotypic slice culture with human patient serum or rabbit CDR2 and CDR2L antibodies. The CDR antibody-induced pathology was investigated by high-resolution multiphoton imaging and biochemical analysis. Both human and rabbit CDR antibodies were rapidly internalized by PCs and led to reduced immunoreactivity of calbindin D28K CB and L7-Pcp-2 as well as reduced dendritic arborizations in the remaining PCs. Washout of the CDR antibodies partially recovered CB immunoreactivity, suggesting a transient structural change in CB calcium-binding site. We discovered that CDR2 and CB co-immunoprecipitate. Furthermore, the expression levels of voltage-gated calcium channel Cav2.1, protein kinase C gamma and calcium-dependent protease, calpain-2, were increased after CDR antibody internalization. Inhibition of these signaling pathways prevented or attenuated CDR antibody-induced CB and L7-Pcp-2 immunoreactivity loss, morphological changes and increased protein expression. These results signify that CDR antibody internalization causes dysregulation of cell calcium homeostasis. Hence, drugs that modulate these events may represent novel neuroprotective therapies that limit the damaging effects of CDR antibodies and prevent PC neurodegeneration.

KeywordsCalbindin D28K Calcium homeostasis Paraneoplastic cerebellar degeneration Onconeural Yo antibodies Purkinje cell death Purkinje cell-specific protein-2 AbbreviationsAbsAntibodies

AMPAα-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid

CaCalcium ion

CBCalcium-binding protein calbindin D28K

CDRCerebellar degeneration-related protein

cOTSCCerebellar organotypic slice culture

IgGImmunoglobulin G

L7-Pcp-2Purkinje cell-specific protein-2

PCPurkinje cell

PCDParaneoplastic cerebellar degeneration

PKCProtein kinase C

VGCCVoltage-gated calcium channel

Electronic supplementary materialThe online version of this article doi:10.1007-s00401-014-1351-6 contains supplementary material, which is available to authorized users.

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Autor: Manja Schubert - Debabrata Panja - Mette Haugen - Clive R. Bramham - Christian A. Vedeler

Fuente: https://link.springer.com/







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