Abnormal Expression Of S100A9 Impairs Junctional Adhesion Molecule-A Of Thyroid Follicular Epithelial Cells In Hashimoto’s Thyroiditis Disease

Objective Hashimoto’s thyroiditis(HT)is induced by pathogenic factors to make an autoimmune response in the thyroid,which eventually leads to the destruction of follicular structure in the thyroid gland and hypothyroidism.This study aims to explore the effect of S100A9 in thyroid tissues of HT patients on human thyroid follicular epithelial cells and JAM-A which maintains tight connections between cells,and to understand the role of S100A9 in the pathogenesis of HT,and to provide new therapeutic targets for clinical treatment.Methods 1.Serum samples from 14 healthy subjects,14 simple thyroid nodule patients and 14 HT patients were collected.Content of S100A9 in the above serums was detected by enzyme-linked immunosorbent assay(ELISA).2.Thyroid tissue samples of 7 patients with simple thyroid nodules and 7 patients with HT were collected through surgery.The distribution and expression of S100A9 and JAM-A proteins were detected by immunohistochemistry.3.Small interfering(si-S100A9-100,si-S100A9-267)sequences and negative control(si-Con)sequence,Overexpressed plasmid(pc DNA3.1 S100A9)and no-loaded control(pc DNA3.1)plasmid were transfected into thyroid epithelial cell strain Nthy-ori 3-1.After 48 h,the expression of S100A9 and JAM-A was detected by q PCR and Western blot(WB).4.After S100A9 overexpressed plasmid and no-loaded plasmid were successfully transfected into Nthy-ori 3-1 for 48 h,the changes of cell morphology and number were identified with an inverted microscope,and the level of cell apoptosis is detected by flow cytometry.Results 1.Compared with healthy people or simple thyroid nodule control group,the concentration of serum S100A9 in HT patients was significantly increased.2.Compared with the control of simple thyroid nodule group,the expression of S100A9 was significantly higher(P <0.001)and the expression of JAM-A was lower(P <0.001)in thyroid tissues of HT patients.3.Compared with the correspoding control,S100A9 m RNA expression in Nthy-ori 3-1 cells was significantly decreased after treatment with si RNA-S100A9(P <0.01);although JAM-A m RNA level was not significantly changed,JAM-A protein level was increased.When the Nthy-ori 3-1 cells were transfected with pc DNA3.1 S100A9,the m RNA level of S100A9 was significantly increased(P <0.01),the JAM-A m RNA expression didn’t show a significant change similarly,but the level of JAM-A protein was decreased.4.After 48 h of successful transfection,adhered cells in the S100A9 overexpression group were observed to become round and the number of cells was significantly reduced(P <0.01).Flowcytometry results showed that the level of total apoptosis(early apoptosis + late apoptosis)was significantly increased(P <0.001).Conclusion By inhibiting the expression of JAM-A protein and promoting the apoptosis of thyroid epithelial cells,the abnormally high expression of S100A9 in the thyroid tissues of HT patients had adverse effects on the normal thyroid follicular structure,and was involved in the occurrence and development of hashimoto’s thyroiditis.