Activation of V-Domain Immunoglobulin Suppressor of T-Cell Activation by Baloxavir Marboxil Ameliorates Systemic Lupus Erythematosus through Inhibiting Lysophosphatidylcholine/CD40 Ligand.

Deficiency of the V-domain immunoglobulin suppressor of T-cell activation (VISTA) accelerates disease progression in lupus-prone mice, and activation of VISTA shows therapeutic effects in mouse models of a lupus-like disease. Metabolic reprogramming of T cells in systemic lupus erythematosus (SLE) patients is important in regulating T-cell function and disease progression. However, the mechanism by which VISTA affects the immunometabolism in SLE remains unclear. Here, we demonstrated that the deficiency of VISTA promoted the synthesis of the metabolite lysophosphatidylcholine (LPC) using untargeted metabolomics and increased the protein expression of the CD40 ligand (CD40L). Furthermore, baloxavir marboxil (BXM), a small molecule agonist of VISTA, significantly ameliorated autoantibody production, renal damage, and imbalance of immune cell subpopulations in the models of a lupus-like disease in mice (chronic graft-versus-host disease and MRL/MpJ-Faslpr/J mice) possibly by inhibiting LPC synthesis to downregulate CD40L protein expression and inhibiting aberrant activation of noncanonical nuclear factor-κB pathway. Our results indicated that BXM targeting VISTA ameliorated lupus-like symptoms by altering lipid metabolism and CD40L expression, which offers novel mechanisms and a promising therapy for SLE.