The following is a summary of “Increased Thyroid DPP4 Expression Is Associated With Inflammatory Process in Patients With Hashimoto Thyroiditis,” published in the June 2024 issue of Endocrinology by Wen, et al.

Dipeptidyl peptidase-4 (DPP4) was initially identified as a surface protein in lymphocytes, and its role in lymphocyte infiltration and thyroid tissue destruction in Hashimoto thyroiditis (HT) has been a subject of interest. For a study, researchers sought to investigate DPP4 expression in peripheral blood and thyroid tissue in patients with HT, shedding light on its role in the pathophysiology of HT.

The case-control study recruited 40 drug-naive patients with HT and 81 control individuals. Peripheral blood and thyroid specimens were collected to assess DPP4 expression and activity. Additionally, single-cell RNA sequencing (scRNA-seq) analysis of “para-tumor tissues” samples from dataset GSE184362 and in vitro cell experiments were conducted.

While patients with HT showed similar DPP4 serum concentration and activity as controls, DPP4 expression and activity were significantly elevated in the thyroid tissue of patients with HT compared to controls. ScRNA-seq analysis revealed increased DPP4 expression in HT, predominantly in T cells. In vitro studies demonstrated that inhibiting lymphocyte DPP4 activity with sitagliptin reduced the production of inflammatory factors in co-cultured thyroid cells.

The study concluded that DPP4 expression was significantly increased in the thyroid tissue of patients with HT, primarily localized in lymphocytes. Inhibition of lymphocyte DPP4 activity may mitigate inflammatory reactions in patients with HT, suggesting the potential therapeutic benefit of DPP4 inhibition in HT management.

Reference: academic.oup.com/jcem/article/109/6/1517/7486580