Expression of the heparan sulfate biosynthesis enzymes NDST1 and NDST2 and their major splice variants in human tissues.

Sammanfattning: The aim of the study was to investigate the expression NDST transcripts in a wide variety of tissues using RNA-sequencing experimental data from five published studies, using two common in silico tools: the Tophat-Cufflink pipeline and the HTSeq-DEXSeq pipeline. We show that to detect NDST alternative transcripts, paired-end sequencing should be used with replicates of samples or conditions together with 100 base read length to allow for reliable detection of the low expressed transcripts in the NDST family.  As a demonstration project, we also characterized HS synthesized by the adrenal carcinoma (ACC) cell line H295R and determined expression of NDSTs in the cells and in ACC tumor samples. We could show that roughly 65% of newly synthesized proteoglycans isolated after metabolic 35S-sulfate labeling of the cells are made up of heparan sulfate (HS) with an average chain length of 45 kDa. The HS chains show a high frequency of N-sulfation and a high total degree of sulfation. Interestingly, disaccharide analysis demonstrated a three-time higher amount of stored chondroitin sulfate (CS) compared to HS in the ACC cell line.