Previous studies indicated that a ganglioside 9acGD3 (9-O-acetyl GD3) antibody [the J-Ab (Jones antibody)] reduces GCP (granule cell progenitor) migration in vitro and in vivo. We here investigated, using cerebellar explants of post-natal day (P) 6 mice, the mechanism by which 9acGD3 reduces GCP migration. We found that immunoblockade of the ganglioside with the J-Ab or the lack of GD3 synthase reduced GCP in vitro migration and the frequency of Ca2+ oscillations. Immunocytochemistry and pharmacological assays indicated that GCPs expressed P2Y1Rs (P2Y1 receptors) and that deletion or blockade of these receptors decreased the migration rate of GCPs and the frequency of Ca2+ oscillations. The reduction in P2Y1-mediated calcium signals seen in Jones-treated and GD3 synthase-null GCPs were paralleled by P2Y1R internalization. We conclude that 9acGD3 controls GCP migration by influencing P2Y1R cellular distribution and function.
Keywords: cerebellar granule cell, Jones antibody, GD3 synthase, P2Y1 receptor, calcium signalling and neuronal migration
Abbreviations: 9acGD3, 9-O-acetyl GD3; DAPI, 4′,6-diamidino-2-phenylindole; DMEM, Dulbecco's modified Eagle's medium; DPBS, Dulbecco's PBS; eGFP, enhanced green fluorescent protein; GCP, granule cell progenitor; GFAP, glial fibrillary acidic protein; J-Ab, Jones antibody; MAP, microtubule-associated protein; P2R, purinergic P2 receptor; WT, wild-type