Protein therapeutics are being widely used for supplementing or modulating biological functions, targeting various cell types, vaccination and diagnostics. Compared to small molecule drugs, proteins are potentially advantageous in exerting more complicated functions, higher specificity and higher bio-compatibility. Nevertheless, proteins are prone to enzymatic degradation and elimination via renal and hepatic pathways and are too large to diffuse into cells. The development of protein delivery systems such as liposomal nanoparticles would substantially facilitate the use of proteins in clinic.
To prepare and evaluate the efficiency of liposomal magnesium phosphate nanoparticles (LP MgP NP) for intracellular protein (catalase) delivery.
Magnesium phosphate nanoparticles (MgP NP) were prepared by microemulsion precipitation. Catalase encapsulated liposomes (CELP) were prepared by hydrating lipid films (DOTAP:Chol) with catalase solution followed by extrusion. Catalase complexed liposomes (CCLP) were prepared by mixing solutions of empty cationic liposomes and catalase. CELP and CCLP were then mixed with MgP NP to form LP MgP NP. Size and zeta-potential were measured using a Malvern NANO-ZS90 zeta sizer. Hydrogen peroxide degradation assay was used to measure pH-triggered release of catalase from the LP-MgP NP formulation. The delivery of catalase into EA.hy926 cells was determined by the decrease of the reactive oxygen species (ROS) level using fluorescence spectrometry. Catalase (10μg/mice) formulations were administered by intravenous and intranasal routes to female CD-1 mice. Mice lung tissue was analyzed for catalase activity and ROS levels.
Catalase complexed LP-MgP NP were successfully prepared. The diameter of the catalase complexed LP-MgP NP formulation was 170.43 nm (PDI = 0.28) with a zeta-potential of 36.9 mV. Catalase complexed LP MgP NP was sensitive to mildly acidic pH 6.0 at which the nanoparticles released more catalase than at pH 7.4. ROS levels normalized with total cellular protein reduced by 65% when treated with catalase-complexed LP MgP NP, which were significantly lower than catalase-complexed LP without the MgP NP core. Catalase complexed LP-MgP NP significantly lowered ROS levels in mice lungs when delivered intranasally.
Our preliminary data showed that LP MgP NP successfully delivered catalase into the cytosol when tested in vitro and in vivo, showing its great potential for intracellular protein delivery in the clinic.
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Mallika Vadlamudi, Prathyusha Naidu, Yifan Lu, Harshavardan Gurrala, et al.. "Liposomal Magnesium Phosphate Nanoparticles for Intracellular Delivery of Catalase" (2017)
Available at: http://works.bepress.com/xin-guo/8/