RESUMO
Interleukin-10 (IL-10) is a dimeric cytokine with both immunosuppressive and immunostimulatory activities; however, IL-10-based therapies have shown only marginal clinical benefits. Here, we explored whether the stability of the IL-10 receptor complex contributes to the immunomodulatory potency of IL-10. We generated an IL-10 mutant with enhanced affinity for its IL-10Rß receptor using yeast surface display. Compared to the wild-type cytokine, the affinity-enhanced IL-10 variants recruited IL-10Rß more efficiently into active cell surface signaling complexes and triggered greater STAT1 and STAT3 activation in human monocytes and CD8+ T cells. These effects, in turn, led to more robust induction of IL-10-mediated gene expression programs at low ligand concentrations in both human cell subsets. IL-10-regulated genes are involved in monocyte energy homeostasis, migration, and trafficking and in CD8+ T cell exhaustion. At nonsaturating doses, IL-10 did not induce key components of its gene expression program, which may explain its lack of efficacy in clinical settings. Our engineered IL-10 variant showed a more robust bioactivity profile than that of wild-type IL-10 at low doses in monocytes and CD8+ T cells. Moreover, CAR-modified T cells expanded with the engineered IL-10 variant displayed superior cytolytic activity than those expanded with wild-type IL-10. Our study provides insights into how IL-10 receptor complex stability fine-tunes IL-10 biology and opens new opportunities to revitalize failed IL-10 therapies.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Interleucina-10/imunologia , Monócitos/imunologia , Mutação/imunologia , Transdução de Sinais/imunologia , Animais , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/metabolismo , Movimento Celular/genética , Movimento Celular/imunologia , Células Cultivadas , Metabolismo Energético/genética , Metabolismo Energético/imunologia , Perfilação da Expressão Gênica/métodos , Humanos , Interleucina-10/genética , Interleucina-10/metabolismo , Ligantes , Monócitos/citologia , Monócitos/metabolismo , Ligação Proteica , Receptores de Interleucina-10/genética , Receptores de Interleucina-10/imunologia , Receptores de Interleucina-10/metabolismo , Fator de Transcrição STAT1/genética , Fator de Transcrição STAT1/imunologia , Fator de Transcrição STAT1/metabolismo , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/imunologia , Fator de Transcrição STAT3/metabolismo , Células Sf9 , Transdução de Sinais/genética , SpodopteraRESUMO
Cytokines comprise a large family of secreted ligands that are critical for the regulation of immune homeostasis. Cytokines initiate signaling via dimerization or oligomerization of the cognate receptor subunits, triggering the activation of the Janus Kinases (JAKs)/ signal transducer and activator of transcription (STATs) pathway and the induction of specific gene expression programs and bioactivities. Deregulation of cytokines or their downstream signaling pathways are at the root of many human disorders including autoimmunity and cancer. Identifying and understanding the mechanistic principles that govern cytokine signaling will, therefore, be highly important in order to harness the therapeutic potential of cytokines. In this review, we will analyze how biophysical (ligand-receptor binding geometry and affinity) and cellular (receptor trafficking and intracellular abundance of signaling molecules) parameters shape the cytokine signalosome and cytokine functional pleiotropy; from the initial cytokine binding to its receptor to the degradation of the cytokine receptor complex in the proteasome and/or lysosome. We will also discuss how combining advanced protein engineering with detailed signaling and functional studies has opened promising avenues to tackle complex questions in the cytokine signaling field.
