Supplementary Material for: Survivin Impairs the Apoptotic Machinery in CD4⁺ T Cells of Patients with Ulcerative Colitis

Background: The increase in CD4⁺ T cell infiltration and overproduction of CD4⁺ T cell-associated cytokines have been observed in the inflamed colon mucosa of patients with ulcerative colitis (UC); the underlying mechanisms are not fully understood. Survivin plays a critical role in the interference with apoptotic machinery. This study aims to elucidate the role of survivin in the interference with the apoptotic machinery in CD4⁺ T cells of UC patients. Methods: Peripheral blood samples were collected from UC patients (UC group) and healthy subjects (healthy group). The apoptotic status in CD4⁺ T cells was analyzed by flow cytometry. Results: We observed that the expression of survivin was significantly higher in CD4⁺ T cells of UC patients than in healthy subjects. UC CD4⁺ T cells were resistant to apoptosis induction. A complex of survivin and c-Myc, the transcription factor of FasL, was detected in CD4⁺ T cells in UC patients, which prevented the binding of c-Myc to the FasL promoter and interfered with the expression of FasL. Increased expression of survivin prevented the activation-induced CD4⁺ T cells from apoptosis. Conclusions: The data indicate that UC CD4⁺ T cells express high levels of survivin, which impairs the apoptotic machinery in CD4⁺ T cells and prevents the activation-induced CD4⁺ T cell apoptosis. Therefore, target therapy against survivin has translational potential in the treatment of UC patients.