RT Journal Article T1 Splicing factor SRSF1 controls T cell homeostasis and its decreased levels are linked to lymphopenia in systemic lupus erythematosus A1 Katsuyama, Takayuki A1 Juárez Martín-Delgado, Ignacio A1 Krishfield, Suzanne M A1 Kyttaris, Vasileios C A1 Moulton, Vaishali R AB Objective: Lymphopenia is a frequent clinical manifestation and risk factor for infections in SLE, but the underlying mechanisms are not fully understood. We previously identified novel roles for the RNA-binding protein serine arginine-rich splicing factor 1 (SRSF1) in the control of genes involved in signalling and cytokine production in human T cells. SRSF1 is decreased in T cells from patients with SLE and associates with severe disease. Because SRSF1 controls the expression of apoptosis-related genes, we hypothesized that SRSF1 controls T cell homeostasis and, when reduced, leads to lymphopenia.Methods: We evaluated SRSF1 expression in T cells from SLE patients by immunoblots and analysed its correlation with clinical parameters. T cell conditional Srsf1 knockout mice were used to evaluate lymphoid cells and apoptosis by flow cytometry. Quantitative PCR and immunoblots were used to assess Bcl-xL mRNA and protein expression. SRSF1 overexpression was performed by transient transfections by electroporation.Results: We found that low SRSF1 levels correlated with lymphopenia in SLE patients. Selective deletion of Srsf1 in T cells in mice led to T cell lymphopenia, with increased apoptosis and decreased expression of the anti-apoptotic Bcl-xL. Lower SRSF1 expression correlated with low Bcl-xL levels in T cells and lower Bcl-xL levels associated with lymphopenia in SLE patients. Importantly, overexpression of SRSF1 rescued survival of T cells from patients with SLE.Conclusion: Our studies uncovered a previously unrecognized role for SRSF1 in the control of T cell homeostasis and its reduced expression as a molecular defect that contributes to lymphopenia in systemic autoimmunity. PB Oxford University Press SN 1462-0324 SN 1462-0332 YR 2020 FD 2020-03-24 LK https://hdl.handle.net/20.500.14352/96996 UL https://hdl.handle.net/20.500.14352/96996 LA eng NO Katsuyama T, Martin-Delgado IJ, Krishfield SM, Kyttaris VC, Moulton VR. Splicing factor SRSF1 controls T cell homeostasis and its decreased levels are linked to lymphopenia in systemic lupus erythematosus. Rheumatology (Oxford). 2020 Aug 1;59(8):2146-2155. doi: 10.1093/rheumatology/keaa094 DS Docta Complutense RD 11 abr 2025