RESUMEN
CD95L is a transmembrane ligand (m-CD95L) that is cleaved by metalloproteases to release a soluble ligand (s-CD95L). Unlike m-CD95L, interaction between s-CD95L and CD95 fails to recruit caspase-8 and FADD to trigger apoptosis and instead induces a Ca2+ response via docking of PLCγ1 to the calcium-inducing domain (CID) within CD95. This signaling pathway induces accumulation of inflammatory Th17 cells in damaged organs of lupus patients, thereby aggravating disease pathology. A large-scale screen revealed that the HIV protease inhibitor ritonavir is a potent disruptor of the CD95-PLCγ1 interaction. A structure-activity relationship approach highlighted that ritonavir is a peptidomimetic that shares structural characteristics with CID with respect to docking to PLCγ1. Thus, we synthesized CID peptidomimetics abrogating both the CD95-driven Ca2+ response and transmigration of Th17 cells. Injection of ritonavir and the CID peptidomimetic into lupus mice alleviated clinical symptoms, opening a new avenue for the generation of drugs for lupus patients.
Asunto(s)
Inflamación/prevención & control , Peptidomiméticos/farmacología , Fosfolipasa C gamma/metabolismo , Células Th17/efectos de los fármacos , Receptor fas/metabolismo , Animales , Antiinflamatorios no Esteroideos/química , Antiinflamatorios no Esteroideos/farmacología , Modelos Animales de Enfermedad , Evaluación Preclínica de Medicamentos/métodos , Femenino , Humanos , Inflamación/metabolismo , Inflamación/patología , Lupus Eritematoso Sistémico/tratamiento farmacológico , Lupus Eritematoso Sistémico/etiología , Masculino , Ratones Mutantes , Simulación del Acoplamiento Molecular , Peptidomiméticos/química , Fosfolipasa C gamma/genética , Dominios Proteicos , Ritonavir/química , Ritonavir/farmacología , Relación Estructura-Actividad , Células Th17/metabolismo , Células Th17/patología , Tiazoles/química , Tiazoles/farmacología , Receptor fas/genéticaRESUMEN
CD95 ligand (CD95L) is expressed by immune cells and triggers apoptotic death. Metalloprotease-cleaved CD95L (cl-CD95L) is released into the bloodstream but does not trigger apoptotic signaling. Hence, the pathophysiological role of cl-CD95L remains unclear. We observed that skin-derived endothelial cells from systemic lupus erythematosus (SLE) patients expressed CD95L and that after cleavage, cl-CD95L promoted T helper 17 (Th17) lymphocyte transmigration across the endothelial barrier at the expense of T regulatory cells. T cell migration relied on a direct interaction between the CD95 domain called calcium-inducing domain (CID) and the Src homology 3 domain of phospholipase Cγ1. Th17 cells stimulated with cl-CD95L produced sphingosine-1-phosphate (S1P), which promoted endothelial transmigration by activating the S1P receptor 3. We generated a cell-penetrating CID peptide that prevented Th17 cell transmigration and alleviated clinical symptoms in lupus mice. Therefore, neutralizing the CD95 non-apoptotic signaling pathway could be an attractive therapeutic approach for SLE treatment.
