Background/Purpose: Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by inflammation and joint destruction. Angiogenesis and cytokine production are involved in the pathogenesis of RA. We have shown that soluble H and Lewis^y antigens are mediators of angiogenesis and are upregulated in the RA joints compared to normal (NL) or osteoarthritis (OA) joints. Fucosyltranseferase 1 (fut1) is an α(1,2)-fucosyltransferase responsible for synthesis of the H blood group and Lewis^y antigens. However, a direct role for fut1 in RA has not been demonstrated. In this study, we examined the expression of fut1 in RA synovial tissue (ST) and determined  the functional consequences of fut1 expression.

Methods: Fut1 expression was determined in RA, OA and NL ST samples by immunohistological staining. To determine whether fut1 was expressed by the human microvascular endothelial cell line (HMEC-1) and human dermal microvascular endothelial cells (HMVECs), real time polymerase chain reaction (RT-PCR) was performed. To block the expression of fut1, HMEC-1s and HMVECs were transfected with fut1 sense or antisense oligonucleotides (ODNs). After treatment, cells were stimulated with interleukin-1β (IL-1β), IL-17 or phorbol 12-myristate 13-acetate (PMA) to stimulate cytokine expression. We examined monocyte chemotactic protein (MCP)-1/CCL2 expression as this chemokine has been shown to be decreased in mouse KRN arthritis induced fut1 knockout joints. We also examined angiogenic vascular endothelial growth factor (VEGF) and regulated upon activation and normal T-cell expressed, and secreted (RANTES)/CCL5 expression, as these cytokines have been shown to be important in RA pathogenesis. In addition, we isolated endothelial cells (ECs) from wild type (wt) and fut1 knockout mice. To confirm the role of fut1 in angiogenesis, we performed EC chemotaxis using wt and fut1 knockout ECs in modified Boyden chambers.

Results: RA STs contained a greater percentage of fut1 ECs than did OA or NL STs [mean ± SEM; RA ST (n=18) 34 ± 8%; OA ST (n=18) 14 ± 6% and NL ST (n=18) 11 ± 4%, p<0.05 between RA ST and OA ST; RA ST and NL ST]. To determine if fut1 expression was inducible by inflammatory cytokines, we stimulated ECs with IL-1β and found that fut1 messenger RNA (mRNA) was IL-1β inducible in HMEC-1s and HMVECs.  Fut1 antisense ODN transfected HMEC-1s and HMVECs had significantly decreased expression of MCP-1/CCL2 and RANTES/CCL5 compared to fut1 sense ODN transfected cells stimulated with  IL-1β, IL-17 or PMA at the mRNA and protein levels (p<0.05). Fut1 knockout mouse ECs stimulated with IL-1β expressed less VEGF mRNA than wt ECs (p<0.05). These results indicate that fut1 regulates EC expression of cytokines important in RA pathogenesis. Finally, fut1 knockout mouse ECs had decreased migration to VEGF compared with wt mouse ECs (10 ± 1 vs. 16 ± 1 cells migrated, n=6 experiments, p<0.05).

Conclusion: These data show that fut1 is overexpressed in RA ST, and that by blocking fut1 expression, we can modify the production of many proinflammatory cytokines. In addition, we show that fut1 regulates EC migration, a facet of angiogenesis in response to VEGF. Hence, fut1 may be an important new target for RA therapy.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/fucosyltransferase-1-fut1-is-overexpressed-in-rheumatoid-arthritis-synovial-tissue-and-modifies-cytokine-production/