Estradiol beta-D-xyloside, an efficient primer for heparan sulfate biosynthesis

Area of Science:

• Biochemistry
• Cell Biology
• Glycobiology

Background:

• Animal cells use beta-D-xylosides as primers for glycosaminoglycan (GAG) synthesis.
• Most xylosides primarily stimulate chondroitin sulfate (CS) synthesis, with limited efficacy in priming heparan sulfate (HS) synthesis.

Purpose of the Study:

• To investigate if the aglycone structure of beta-D-xylosides influences the type of GAG synthesized.
• To compare the priming activity of various beta-D-xylosides on GAG synthesis.

Main Methods:

• Tested the priming activity of methyl, n-octyl, p-nitrophenyl, 4-methylumbelliferyl, trans,trans-farnesyl, cholesteryl, and estradiol beta-D-xylosides.
• Utilized pgsA-745 Chinese hamster ovary (CHO) cells, a mutant deficient in xylosyltransferase, to assess GAG synthesis initiation.
• Evaluated HS synthesis induction in various cell types, including wild-type CHO cells, bovine aortic endothelial cells, baby hamster kidney cells, and Balb/c 3T3 fibroblasts.

Main Results:

• All tested xylosides stimulated CS synthesis in the pgsA-745 mutant cells.
• Estradiol beta-D-xyloside was unique in efficiently priming heparan sulfate (HS) synthesis.
• Mutant cells treated with estradiol beta-D-xyloside produced 3-fold more GAGs than untreated wild-type cells, with up to 50% HS.
• Estradiol beta-D-xyloside induced HS synthesis in multiple cell types and inhibited endogenous HS proteoglycan formation at low concentrations.

Conclusions:

• The aglycone structure of beta-D-xylosides is critical in determining the type of glycosaminoglycan synthesized.
• Estradiol beta-D-xyloside serves as an effective primer for heparan sulfate synthesis, offering a novel tool for GAG research.
• This finding has implications for understanding and manipulating GAG biosynthesis pathways.