Increased Thyroid DPP4 Expression Is Associated With Inflammatory Process in Patients With Hashimoto Thyroiditis.

Area of Science:

• Immunology
• Endocrinology
• Molecular Biology

Background:

• Dipeptidyl peptidase-4 (DPP4) is a surface protein on lymphocytes.
• Lymphocyte infiltration and thyroid destruction are key in Hashimoto thyroiditis (HT).

Purpose of the Study:

• Investigate DPP4 expression and activity in HT patients' peripheral blood and thyroid tissue.
• Explore DPP4's role in HT pathogenesis.

Main Methods:

• Case-control study with 40 drug-naive HT patients and 81 controls.
• Assessed DPP4 expression and activity in blood and thyroid specimens.
• Utilized single-cell RNA sequencing and in vitro cell experiments.

Main Results:

• DPP4 serum levels were similar between HT patients and controls.
• Thyroid DPP4 expression and activity were significantly higher in HT patients.
• scRNA-seq revealed increased DPP4 in HT T cells; sitagliptin inhibited inflammatory factors in vitro.

Conclusions:

• Thyroid DPP4 expression, mainly in lymphocytes, is increased in HT.
• Inhibiting lymphocyte DPP4 activity reduces inflammatory factor production.
• DPP4 inhibition shows potential for alleviating inflammation in HT.