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Contribution of heparan sulfate to the non‐permissive role of the midline glia to the growth of midbrain neurites
Author(s) -
GarciaAbreu José,
Mendes Fabio A.,
Onofre Glaucia R.,
De Freitas Marta S.,
Silva Luiz C.F.,
Moura Neto Vivaldo,
Cavalcante Leny A.
Publication year - 2000
Publication title -
glia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.954
H-Index - 164
eISSN - 1098-1136
pISSN - 0894-1491
DOI - 10.1002/(sici)1098-1136(20000201)29:3<260::aid-glia7>3.0.co;2-i
Subject(s) - neurite , biology , microbiology and biotechnology , astrocyte , neuroglia , laminin , heparan sulfate , chondroitin sulfate proteoglycan , glycosaminoglycan , chondroitin sulfate , neuroscience , biochemistry , central nervous system , extracellular matrix , in vitro
Radial glial cells and astrocytes are heterogeneous with respect to morphology, cytoskeletal‐ and membrane‐associated molecules and intercellular interactions. Astrocytes derived from lateral (L) and medial (M) midbrain sectors differ in their abilities to support neuritic growth of midbrain neurons in coculture (Garcia‐Abreu et al. J Neurosci Res 40:471, 1995). There is a correlation between these abilities and the differential patterns of laminin (LN) organization that is fibrillar in growth‐permissive L astrocytes and punctate in the non‐permissive M astroglia (Garcia‐Abreu et al. NeuroReport 6:761, 1995). There are also differences in the production of glycosaminoglycans (GAGs) by L and M midbrain astrocytes (Garcia‐Abreu et al. Glia 17:339, 1996). We show that the relative amounts of the glycoproteins laminin LN, fibronectin (FN) and tenascin (TN) are virtually identical in L and M glia, thus, confirming that an abundant content of LN is not sufficient to promote neurite growth. To further analyze the role of GAGs in the properties of M and L glia, we employed enzymatic degradation of the GAGs chondroitin sulfate (CS) and heparan sulfate (HS). Treatment with chondroitinase has little effect on the non‐permissive properties of M glia but reduces the growth‐supporting ability of L glia. By contrast, heparitinase I produces no significant changes on L glia but leads to neurite growth promotion by M glia. Taken together, these results suggest that glial CS helps to promote neurite growth and, more importantly, they indicate that a HS proteoglycan is, at least, partially responsible for the non‐permissive role of the midline glia to the growth of midbrain neurites. GLIA 29:260–272, 2000. © 2000 Wiley‐Liss, Inc.