A novel approach for investigating glycan involvement in embryonic cellular interactions

We use the NIH sea urchin embryo model to investigate molecular mechanisms of cellular interactions. Twenty‐four hour Strongylocentrotus purpuratus e mbryo s were incubated with 14 different sugars in low calcium seawater (that speeds molecular entry into the living embryo blastocoel) using a microplate assay. Three experiments with 10 replicate wells, and hundreds of embryos for each sugar concentration and controls without sugar showed that the most effective sugars were alpha cyclodextrin, fructose, and maltotriose in inhibiting archenteron elongation/attachment at 3 mM concentration. Cyclodextrin and maltotriose are polymers of glucose monosaccharide that was a less effective inhibitor. In all cases, unpaired t‐tests revealed p values of less than 0.05, when comparing archenteron attachment versus no attachment in the sugar samples vs controls. In these experiments, sugars were tested at concentrations of 0.6 mM ‐ 330 mM. In new experiments lower sugar concentrations are being tested to more definitively identify those sugars that are most effective at the lowest concentrations. The working hypothesis is that specific sugars enter the embryo blastocoel and bind to receptors involved in the cellular interaction. Information on lowest effective sugar concentrations should help pin down those sugars that might be more likely to be involved in the cellular interaction under study. The use of sugars, low calcium sea water and a quantitative microplate assay, that easily identifies specific embryo morphologies, is a novel approach for helping to elucidate the nature of glycan‐involved cellular interactions in many different systems (supported by NIH NIGMS SCORE (S0648680), RISE, MARC, the Joseph Drown Foundation and the Sidney Stern Memorial Trust).