Hippocampal neurons and recombinant galectins as tools for systematic carbohydrate structure-function studies in neuronal differentiation.
Membrane glycoconjugates play a central role in neuronal interactions and regulation. To define the precise links between membrane polysaccharides and neuronal functions, two main requirements must be fulfilled: (1) the availability of molecular tools able to finely discriminate among carbohydrate structures and (2) the use of an experimental system suitable for systematic and quantitative studies of particular neuronal processes. In this work, we used two chicken proto-type galectins, i.e., monomeric CG-14 and dimeric CG-16, with very similar carbohydrate affinities, and rat hippocampal neurons in culture to quantitatively measure the involvement of carbohydrate-protein interaction in axonal growth and directionality, neurite sprouting and axon regenerative capacity after section. CG-16 potently stimulated axonal growth and guidance. Neurite sprouting was enhanced by immobilized CG-16 and, notably, reduced by lectin in solution. Overall, cross-linking CG-16 invariably excelled CG-14 in these functional assays, although none of them were able to improve axon regenerative capacity when compared to mammalian galectin-1. Our results demonstrate the potential of the experimental set-up to perform a systematic study of galectin functionality in neuronal differentiation. In view of the concept of the sugar code, the presented results indicate that biological effects triggered by glycan binding engaging an endogenous lectin can be modulated by carbohydrate affinity and/or by other factors like differential cross-linking capacity.
Kopitz
Jürgen
J
Institut für Molekulare Pathologie, Klinikum der Ruprecht-Karls-Universität, Im Neuenheimer Feld 220, D-69120 Heidelberg, Germany.
Russwurm
Roland
R
Kaltner
Herbert
H
André
Sabine
S
Dotti
Carlos G
CG
Gabius
Hans-Joachim
HJ
Abad-Rodríguez
José
J
D000818:Animals; D001369:Axons / Q000187:drug effects / Q000502:physiology; D002241:Carbohydrates / Q000737:chemistry* / Q000502:physiology*; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D002642:Chick Embryo; D016650:Fluorescein-5-isothiocyanate; D005455:Fluorescent Antibody Technique; D005456:Fluorescent Dyes; D037161:Galectins / Q000494:pharmacology*; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D007785:Lactose / Q000378:metabolism; D008566:Membranes / Q000187:drug effects / Q000378:metabolism; D009416:Nerve Regeneration / Q000187:drug effects / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000494:pharmacology; D016501:Neurites / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011994:Recombinant Proteins / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013329:Structure-Activity Relationship
D002241:Carbohydrates; D005456:Fluorescent Dyes; D037161:Galectins; D009419:Nerve Tissue Proteins; D011994:Recombinant Proteins; D016650:Fluorescein-5-isothiocyanate; D007785:Lactose