The Study Of The Role Of Galectin-9^lowDC In The Progression Of Hashimoto’s Thyroiditis

Hashimoto thyroiditis is an autoimmune disease which clinically mainly manifests as lesion such as the medium swelled, growing stiff and gradually lymphocytes infiltrating in the thyroid of patients. HT also pathologically manifests as the existence of high concentration of TPOAb and TgAb in peripheral blood and activated Thl cells and CD8+T cells migration into thyroid of patients. In which CD8+T cells largely cause inflammatory injury in thyroid. Dendritic cells which function as the principal antigen-presenting cells in the immune system can activate CD8+T cells and avail its cytotoxic ability. Thus DCs may play important and latent roles in the progression of HT. We are purposed to detect the differential expression of glycoproteins and discover the roles of them in HT.Peripheral blood samples of 16 HT patients and 22 healthy donors were harvested and DCs were sorted. Lectin microarrays were performed to detect the differential expressed glycoproteins, the results showed that Galectin-9 was outstanding. Lectin-bound glucan was utilized to pull down the glycoproteins of DCs cytomembrane and the glycoproteins pulled down were detected through mass spectrum identification. The results showed that Galectin-9 still was outstanding. Then qRT-PCR and Western blotting were performed to detect the expression of Galectin-9 in DCs of HT patients and healthy donors respectively, the results showed that there was significant lower expression of Galectin-9 in DCs from peripheral blood of HT patients.DCs were stained by FITC-CD11c and PE-anti-Galectin-9 and then separated by FCM, the results showed there were significant lower expression of Galectin-9 in part of DCs and which was named Galectin-9low DCs. There were significant much more Galectin-9lowDCs in HT patients. Galectin-9lowDCs were co-cultured with CD8+T cells and the secretion of IFN-gamma, perforin and granzyme B was detected by ELISA. The results showed that Galectin-9lowDCs could significantly promote the generation of IFN-gamma, perforin and granzyme B of CD8+T cells.To further study the function of Galectin-9 in DCs, Galectin-9 gene was cloned, then pcDNA3.1-Galectin-9 was constructed and transfected into Galectin-9lowDCs. After co-cuture with these Galectin-9lowDCs, CD8+T cells no longer showed a stronger ability to secret IFN-gamma, perforin and granzyme B.pET-28a-Galectin-9 was constructed at the same time and Galectin-9 protein was extracted. Ectogenic Galectin-9 of different concentration gradient was added while CD8+T cells were co-cultured with Galectin-9lowDCs, gradual reduction of the secretion of IFN-gamma, perforin and granzyme B was observed.The study above showed that Galectin-9lowDCs in peripheral blood of HT patients can promote the secretion of IFN-gamma, perforin and granzyme B and enhance the cytotoxic ability of CD8+T cells, thus led to the exacerbation of HT. While when transinfected with pcDNA3.1-Galectin-9 or treated with ectogenic Galectin-9 protein, Galectin-9lowDCs could not stengthen CD8+T cells. So we can draw a prudent conclusion that Galectin-9 may be a new target for treatment of HT, up-ragulate the expression of Galectin-9 could be a potential cure to stop the exacerbation of HT.