RESUMO
Protein arginine methyltransferase 5 (PRMT5) catalyzes symmetric dimethylation (SDM) of arginine, a posttranslational modification involved in oncogenesis and embryonic development. However, the role and mechanisms by which PRMT5 modulates Th cell polarization and autoimmune disease have not yet been elucidated. Here, we found that PRMT5 promoted SREBP1 SDM and the induction of cholesterol biosynthetic pathway enzymes that produce retinoid-related orphan receptor (ROR) agonists that activate RORγt. Specific loss of PRMT5 in the CD4+ Th cell compartment suppressed Th17 differentiation and protected mice from developing experimental autoimmune encephalomyelitis (EAE). We also found that PRMT5 controlled thymic and peripheral homeostasis in the CD4+ Th cell life cycle and invariant NK (iNK) T cell development and CD8+ T cell maintenance. This work demonstrates that PRMT5 expression in recently activated T cells is necessary for the cholesterol biosynthesis metabolic gene expression program that generates RORγt agonistic activity and promotes Th17 differentiation and EAE. These results point to Th PRMT5 and its downstream cholesterol biosynthesis pathway as promising therapeutic targets in Th17-mediated diseases.
Assuntos
Autoimunidade , Diferenciação Celular/imunologia , Colesterol/imunologia , Encefalomielite Autoimune Experimental/imunologia , Proteína-Arginina N-Metiltransferases/imunologia , Células Th17/imunologia , Animais , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/patologia , Diferenciação Celular/genética , Colesterol/genética , Encefalomielite Autoimune Experimental/genética , Encefalomielite Autoimune Experimental/patologia , Camundongos , Camundongos Transgênicos , Células T Matadoras Naturais/imunologia , Células T Matadoras Naturais/patologia , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/genética , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/imunologia , Proteína-Arginina N-Metiltransferases/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/imunologia , Células Th17/patologiaRESUMO
Chemical signals are conveyed to cells through ligand-receptor binding, triggering cascades of biochemical reactions and resulting in pivotal cellular functions. These binding events are important in understanding membrane signaling and drug interactions. To probe ligand-receptor binding, surface enhanced Raman scattering (SERS) tags are a promising tool. SERS tags are plasmonic nanostructures functionalized with a protective coating, a Raman reporter molecule, and a biorecognition element. In biological fluids, native proteins have affinity for bare nanoparticles and form a protein corona. SERS tags have a protective shell which eliminates this complication. It is important to analyze ligand-receptor binding with SERS tags in live cells since cell fixatives alter protein structure, leading to spectral changes and data misinterpretation. In this study, we synthesized a novel SERS tag by creating a mixed monolayer of the small cyclic arginine-glycine-aspartic acid-phenylalanine-cysteine (RGDFC) peptide and 4-mercaptobenzonitrile (MBN) on the surface of spherical gold nanoparticles (Au NP). Au-RGDFC-MBN NP showed resistance to PC formation and were successfully detected in both fixed and living human metastatic colon cancer cells.
