Suppression of glucose-6-phosphate-isomerase induced arthritis by oral administration of transgenic rice seeds expressing altered peptide ligands of glucose-6-phosphate-isomerase

Abstract

Objective: To investigate the effects of transgenic rice seeds expressing the altered peptide ligand (APL) of human glucose-6-phosphate-isomerase (hGPI_325–339) in mice model of GPI-induced arthritis (GIA).

Methods: We generated transgenic rice expressing T-cell epitope of hGPI_325–339 and APL12 contained in the seed endosperm. The transgenic rice seeds were orally administered prophylactically before the induction of GIA. The severity of arthritis and titers of serum anti-GPI antibodies were evaluated. We examined for IL-17 production in splenocytes and inguinal lymph node (iLN) cells, and analyzed the expression levels of functional molecules in splenocytes.

Results: Prophylactic treatment of GIA mice with APL12 transgenic (APL12-TG) rice seeds significantly reduced the severity of arthritis and titers of serum anti-GPI antibodies compared with non-transgenic (Non-TG) rice-treated mice. APL12-TG and hGPI_325–339 transgenic (hGPI_325–339-TG) rice seeds improved the histopathological arthritis scores and decreased IL-17 production compared with non-TG rice-treated mice. APL12-TG rice-treated GIA mice showed upregulation of Foxp3 and GITR protein in CD4 ⁺ CD25 ⁺ Foxp3⁺cells in the spleen compared with non-TG rice- and hGPI_325–339-TG rice-treated mice.

Conclusion: APL12-TG rice seeds improved the severity of GIA through a decrease in production of IL-17 and anti-GPI antibodies via upregulation of Foxp3 and GITR expression on Treg cells in spleen.

Keywords:

• Altered peptide ligands
• glucose-6-phosphate-isomerase
• arthritis

Conflict of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.