ObjectiveTo investigate the expression of α7 nicotinic acetylcholine receptor (α7 nAChR) in thymocytes of patients with myasthenia gravis (MG) and its effect on cytokine secretion and T cell proliferation. MethodsPatients with MG who underwent expanded thoracoscopic thymectomy in the Comprehensive Diagnosis and Treatment Center of the Henan Provincial People’s Hospital from June 2021 to June 2022 were selected and allocated to a MG group. Patients who underwent partial thymectomy to expose the surgical field during the cardiac disease surgery from June 2021 to September 2022 in the Department of Adult Cardiac Surgery of Fuwai Huazhong Cardiovascular Hospital were selected as the control group. Thymic single cell suspensions were prepared from MG and control groups, and the expression of α7 nAChR in thymocytes of the two groups was detected by real-time polymerase chain reaction and Western blotting. Then CD3/CD28 monoclonal antibody coupled with magnetic beads was used to induce T cell activation, and the levels of cytokines interferon-gamma (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-4 (IL-4), IL-6, IL-10, IL-17, and IL-21 in thymocytes of the two groups were detected by enzyme-linked immunosorbent assay (ELISA). The activated T cells of the MG group were divided into a blank control group, an α7 nAChR antagonist group, and an α7 nAChR agonist group according to different treatment methods. After 72 hours of culture, IFN-γ, TNF-α, IL-4, IL-6, IL-10, IL-17, and IL-21 expression levels in the culture supernatant were measured by ELISA. Afterwards, CD4-PE and CD8-APC antibodies were added, and the proliferation of T cell subsets was detected by flow cytometry. ResultsA total of 10 MG patients were collected, including 3 males and 7 females with an average age of 19.25±6.28 years; and 15 control patients were collected, including 6 males and 9 females with an average age of 26.18±6.77 years. Compared with the control group, the mRNA and protein levels of α7 nAChR in the thymocytes of MG group were decreased, and the expression levels of IFN-γ, TNF-α, IL-4, IL-6 and IL-21 in the supernatant were increased (P<0.05), but there was no statistical difference in the expression of IL-10 and IL-17 (P>0.05). The cell-culture experiment showed that compared with the blank control group, the levels of IFN-γ, TNF-α, IL-6 and IL-21 secreted by T cells in the α7 nAChR antagonist group were increased (P<0.05), while they were decreased in the α7 nAChR agonist group (P<0.05). There was no statistical difference in the secretion levels of IL-4, IL-10 or IL-17 among the three groups (P>0.05). CD4+ T and CD8+ T cells in the α7 nAChR agonist group were significantly less than those in the blank control group and α7 nAChR antagonist group (P<0.001), while they were significantly more in the α7 nAChR antagonist group than those in the blank control group (P<0.001).ConclusionThe expression of α7 nAChR in thymocytes of MG patients is decreased, and α7 nAChR may be involved in the inflammatory response in thymocytes and thus in thymic function.
Objective To investigate the role of T follicular helper cells (TFH) and their expression of α7 nicotinic acetylcholine receptor (α7nAChR) in patients with Myasthenia gravis (MG). Methods Fifteen MG patients who underwent surgical treatment in the Myasthenia Gravis Comprehensive Diagnosis and Treatment Center of Henan Provincial People's Hospital from June 2022 to June 2023 were selected as the MG group, including 7 males and 8 females, aged 12-30 years. Twelve healthy individuals who underwent partial thymectomy without obstruction during cardiac surgery in Fuwai Central China Cardiovascular Hospital from June 2022 to June 2023 were selected as the healthy control group, including 5 males and 7 females aged 20-35 years. Thymus single cell suspension was obtained by grinding the thymus tissue, and flow cytometry was used to detect the expression of α7nAChR in TFH cells. The thymus cell suspension was purified using density gradient centrifugation, followed by immunomagnetic bead separation to obtain CD4+T cells. CXCR5 antibody and coupled magnetic beads were added to isolate TFH cells. Real-time fluorescent polymerase chain reaction (RT-PCR) and Western blotting were performed to further investigate the expression of α7nAChR in TFH cells. Results Compared with the healthy control group, there was a significant decrease in α7nAChR levels within thymic TFH cells in the MG group (P<0.001), along with significantly decreased mRNA and protein expression levels of α7nAChR within these cells (P<0.01). Conclusion The findings suggest that there is a reduced expression of α7nAChR within thymic TFH cells in MG patients, leading to weakened immunosuppressive function which may indirectly contribute to disease onset and progression.