Controlled release formulations of IL-2, TGF-β1 and rapamycin for the induction of regulatory T cells

Abstract

The absence of regulatory T cells (Treg) is a hallmark for a wide variety of disorders such as autoimmunity, dermatitis, periodontitis and even transplant rejection. A potential treatment option for these disorders is to increase local Treg numbers. Enhancing local numbers of Treg through in situ Treg expansion or induction could be a potential treatment option for these disorders. Current methods for in vivo Treg expansion rely on biologic therapies, which are not Treg-specific and are associated with many adverse side-effects. Synthetic formulations capable of inducing Treg could be an alternative strategy to achieve in situ increase in Treg numbers. Here we report the development and in vitro testing of a Treg-inducing synthetic formulation that consists of controlled release vehicles for IL-2, TGF-β and rapamycin (a combination of cytokines and drugs that have previously been reported to induce Treg). We demonstrate that IL-2, TGF-β and rapamycin (rapa) are released over 3-4 weeks from these formulations. Additionally, Treg induced in the presence of these formulations expressed the canonical markers for Treg (phenotype) and suppressed naïve T cell proliferation (function) at levels similar to soluble factor induced Treg as well as naturally occurring Treg. Most importantly, we show that these release formulations are capable of inducing FoxP3+ Treg in human cells in vitro. In conclusion, our data suggest that controlled release formulations of IL-2, TGF-β and rapa can induce functional Treg in vitro with the potential to be developed into an in vivo Treg induction and expansion therapy.

Paracrine co-delivery of TGF-β and IL-2 using CD4-targeted nanoparticles for induction and maintenance of regulatory T cells

“…Sustained release of both cytokines was comparable due to physiochemical similarities between both proteins. Both cytokines have individually been encapsulated in PLGA matrices previously [30,32], but they have not been co-encapsulated in the same particle. To verify preservation of each cytokine’s structure following PLGA encapsulation and particle synthesis, we assayed for bioactivity during particle-mediated release.…”

“…Therefore, we chose to use nanoparticles composed of poly(lactic-co-glycolic) acid (PLGA), which have been used extensively for the controlled delivery of various proteins to many cell types [28–30]. Given the clear goal here, directed delivery of pleiotropic cytokines to CD4 + T cells, and its clinical implication for autoimmune treatment, we chose to use the simplest and most ubiquitous nanocarrier delivery system.…”

Role of Cytokines and Transcription Factors in Periodontitis: A Review of Cellular and Molecular Mechanisms

“…A potential treatment option for these disorders revolves around increasing the number of Tregs in local sites (Jhunjhunwala et al, 2012;Gonzales et al, 2013). Current methods for in vivo expansion of Tregs depend on biological therapies, which are not specific for Tregs and are still associated with many adverse side effects.…”

“…These formulations were also able to induce transcription factors FoxP3+ Tregs in human cells in vitro. The authors concluded that the combination of these microparticle formulations have the potential to be used for the in vivo induction of Tregs at local sites of rejected transplants or autoimmunity (Jhunjhunwala et al, 2012).…”

“…Moreover, the modulation of the host immune system by drugs may result in adverse side effects, requiring close monitoring of patients for trying this approach (Jhunjhunwala et al, 2012). Therefore, additional studies are needed to understand the onset and progression of periodontitis and to develop therapeutic interventions able to treat and control the disease.…”