The results reported indicate that a clonal glial cell strain is capable
of synthesizing three different acid mucopolysaccharides: hyaluronic acid,
chondroitin 4-sulfate, and heparan sulfate. That the cell strain is indeed of glial
origin is supported by the fact that it also makes the S-100 brain protein."6 The
formation of these acid mucopolysaccharides by glial cells is of importance with
reference to the suggestions that acid mucopolysaccharides are essential for the
development of myelin of normal structure2 and also for the regulation of
Na+ and K+ in nerve excitation.' Intracisternal injection of testicular hyaluronidase
in cats has been found to cause lethargy, rigidity, and myoclonic
convulsions.13",4 The formation of heparan sulfate by glial cells is of particular
interest since it has been suggested by Kaplan24 that excretion of this compound
in mucopolysaccharidoses is associated with mental retardation. Thus, the
glial cells may represent a source of heparan sulfate in the forms of mucopolysaccharidoses,
especially Sanfilippo's syndrome, in which mental retardation is
prominent and in which heparan sulfate is the predominant polysaccharide excreted.
It is worthy of note that skin fibroblasts in tissue culture do not
produce heparan sulfate even when derived from patients with Sanfilippo's
syndrome. The only previous report of the synthesis of this compound in tissue
culture is that of Kraemer2' utilizing an established cell line of Chinese hamster
fibroblasts.