(168v) Engineering Lipid Nanoparticles for Controlled Spaciotemporal Release of Therapeutic Cargo to Enhance Cell Survivability during Stem Cell Transplant Therapy

Acute lung injury (ALI) is a life-threatening disorder characterized by severe inflammation and destruction of the lung vascular barrier. Studies have demonstrated that mesenchymal stem cells (MSCs) can be utilized to treat ALI due to their immunomodulatory and anti-inflammatory properties. However, the therapeutic efficacy of transplanted MSCs is limited due to the poor cell survival rate in a high oxidative stress microenvironment. Pretreatment of cells with an antioxidant prior to the transplant process can improve cellular function and thus the survival rate of the MSCs. Further lipid nanoparticle (LNP) mediated delivery can enhance the antioxidant's biopharmacokinetics and reduced offsite effects. In this study, we engineered highly customizable Vitamin E-loaded lipid nanoparticles (VitE-LNP) and investigated their effect on boosting the therapeutic capacity of MSCs under high oxidative stress conditions. The LNPs were created in various sizes, surface charges, and coating density of hydrophilic polymer using non-cationic lipid and cholesterol components. LNPs were characterized by both photon correlation spectroscopy to determine particle size distribution, hydrodynamic diameter, and polydispersity, and by zeta potential measurements to determine nanoparticle surface charge characteristics and to quantify colloidal stability. The encapsulation efficiency was evaluated using the standard curve for absorbance measurement of vitamin E at 295 nm wavelength. We obtained stable liposome formulations along with nearly 75% encapsulation efficiency of vitamin E. In vitrostudies were performed to examine the effects of VitE-LNP in mitigating oxidative stress in MSCs induced by peroxide (H₂O₂) treatment. The uptake studies using FITC tagged LNPs in MSCs revealed that the nanocarriers were uniformly internalized into the cytosol. The VitE-LNPs treated cells showed a significant decrease in reactive oxidative stress induced by peroxide. Live dead assay further revealed a significantly lower concentration of dead cells in the VitE-LNP treated group in comparison to the control group just treated with peroxide. We conducted in vivo studies by implanting vit E-LNP pretreated MSC in a mouse model of lipopolysaccharide (LPS) induced ALI. In vivo studies demonstrated that the LPS treated mice implanted with VitE-LNP pretreated MSCs survived for significantly more days in comparison to untreated MSCs. Taken together, our findings from both in vitro and in vivo experiments indicate that VitE-LNP treatment can ameliorate the quality of MSCs and enhance their survival rate during the transplant process. This LNP design can potentially be utilized to enhance the immunoregulatory functions of MSCs and mediate their clinical translation for ALI therapy.