Background

Complications caused by long-term immunosuppression remain a major concern for transplant patients. To optimize controlled and accurate dosing, we investigated an innovative drug delivery method based on solid lipid nanoparticles (SLN) to deliver the immunosuppressive drug tofacitinib (Tofa) and to explore its use as adjuvant for tolerogenic strategies.

Methods

Bone marrow derived dendritic cells (DC) from Balb/c mice were exposed to titrations of Tofa-containing SLN (Tofa-SLN), empty control SLN (c-SLN), or left untreated. After a 6 or 24h pre-incubation, overnight maturation was induced with LPS. Toxicity of SLN was assessed by measuring viability of DC. DC maturation was determined via expression of CD40, CD86, CD80, and MHC-II. Allostimulatory capacity of SLN-conditioned DC was assessed via CFSE-MLR. Using fluorescently-labeled SLN, uptake kinetics by DC was investigated in vitro; and in vivo SLN distribution was studied via live imaging after subcutaneous or intraperitoneal injection.

Results

Significant uptake of SLN by DC was observed after 5 min of exposure to fluorescent nanoparticles and plateaued within 40 min. Non-toxic concentrations of SLN were determined and used for all experiments. DC exposed to Tofa-SLN showed a dose dependent inhibition of JAK/STAT signaling (target of Tofa) confirming release of the drug. Tofa-SLN conditioned DC were profoundly inhibited in their maturative response to LPS. This was indicated by lower expression of maturation markers compared to c-SLN-DC. Accordingly, CD4+ and CD8+ T-cell proliferation induced by Tofa-SLN-DC was significantly decreased when compared to c-SLN-DC or untreated DC. In vivo imaging via epifluorescence and 3D reconstruction showed persistence of SLN around the site of injection for more than 96h. More importantly, a clear signal appeared at the draining lymph nodes at 24h post injection and lasted over 96h.

Conclusion

Tofa-SLN are very effective in targeting DC, regulating their maturation and allostimulatory capacity. The selective accumulation in the lymphoid tissues of SLN injected in vivo suggests continuous uptake and transportation by APCs. This novel delivery system has potential for effective treatment of transplant patients and could facilitate implementation of new immunoregulatory strategies.

CITATION INFORMATION: Budihardjo J, Iglesias M, Walch J, Calderon-Colon X, Lee W, Brandacher G, Patrone J, Raimondi G. Tofacitinib Delivered by Solid Lipid Nanoparticles Inhibits Dendritic Cell Maturation and Their Allostimulatory Capacity. Am J Transplant. 2016;16 (suppl 3).

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