Differential Leukocyte miRNA Responses Following Pan T Cell, Allorecognition and Allosecretome-Based Therapeutics Activation

Abstract

Background Effective immunomodulation of T cell responses is critical in treating both autoimmune diseases and cancer. Our previous studies have demonstrated that secretomes derived from control or methoxypolyethylene glycol (mPEG) mixed lymphocyte alloactivation assays exerted potent immunomodulatory activity that was mediated by microRNAs (miRNA). In this study, the immunomodulatory effects of biomanufactured miRNA-based allo-secretome therapeutics (SYN, TA1, IA1 and IA2) were compared to Pan T cell activators (PHA and anti-CD3/CD28) and alloactivation (MHC-disparate donors; ± mPEG grafting). The differential effects of these activation strategies on resting PBMC were assessed via T cell differentiation and proliferation as well as the differential expression of multiple miRNA.Results Mitogen-induced PBMC proliferation (average of > 85%) significantly exceed that arising from either allostimulation (~ 30%) or the proinflammatory IA1 secretome product (~ 12%). Consequent to stimulation, the ratio of CD4 to CD8 cells of the resting PBMC (CD4:CD8; 1.7 ± 0.1) decreased in the Pan-T cell, allrecognition and IA1 activated cells (average of 1.1 ± 0.2; 1.2 ± 0.1 and 1.0 ± 0.1). These changes arose consequent to the expansion of both CD4+CD8+ and CD4-CD8- populations and the shrinkage of the CD4 subset relative to the expansion of the CD8 T cells. Most importantly, this study demonstrated that these activation strategies exert profoundly unique effects on the differential expression of miRNA within the treated PBMC and that these 'differential patterns of miRNA expression' are associated with significant differences in cellular differentiation and biological function.Conclusions These findings support the concept that the 'differential pattern of miRNA expression', not a change in a single miRNA, governs the biologic immune response in a 'lock and key' manner. The biomanufacturing of miRNA-enriched secretome biotherapeutics may be a successful approach for producing miRNA cocktails (e.g., TA1 and IA1) that replicate the normal biological 'lock and key' miRNA configuration necessary for the systemic treatment of autoimmune diseases (TA1) or enhancing the endogenous immune response to cancer (IA1).