Uricase alkaline enzymosomes with enhanced stabilities and anti-hyperuricemia effects induced by favorable microenvironmental changes

Yunli Zhou,Jianyong Wu,Dan He,Xueyuan Hu,Biyue Zhu,Huarong Xiong,Jingqing Zhang,Mi Zhang

doi:10.1038/srep20136

Abstract

Enzyme therapy is an effective strategy to treat diseases. Three strategies were pursued to provide the favorable microenvironments for uricase (UCU) to eventually improve its features: using the right type of buffer to constitute the liquid media where catalyze reactions take place; entrapping UCU inside the selectively permeable lipid vesicle membranes; and entrapping catalase together with UCU inside the membranes. The nanosized alkaline enzymosomes containing UCU/(UCU and catalase) (ESU/ESUC) in bicine buffer had better thermal, hypothermal, acid-base and proteolytic stabilities, in vitro and in vivo kinetic characteristics, and uric acid lowering effects. The favorable microenvironments were conducive to the establishment of the enzymosomes with superior properties. It was the first time that two therapeutic enzymes were simultaneously entrapped into one enzymosome having the right type of buffer to achieve added treatment efficacy. The development of ESU/ESUC in bicine buffer provides valuable tactics in hypouricemic therapy and enzymosomal application.

Highlights

The ESU and ESUC were successfully prepared with the entrapment efficiencies ranging from ~52%–~57%; the size of ESU ranged from 260 nm–330 nm, whereas the size of ESUC showed a sudden increase to 750–850 nm (Fig. 2A)
The development of better nanosized therapeutic enzymosomes represents a valuable tactic in an effective enzyme therapy that is, totally different from traditional chemotherapy and newly emerging gene therapy
We have developed UCU/(UCU and CAT) alkaline enzymosomes (ESU/ESUC) for efficient UCU delivery to cure hyperuricemia

Summary

Introduction

One catalysate of UCU (hydrogen peroxide) is the sole substrate of CAT ( a therapeutic enzyme)[21], whereas the resulting catalysate of CAT (oxygen) is in turn one substrate of UCU If both UCU and CAT are simultaneously entrapped inside one enzymosome, this should be a novel favorable delivery system (i.e., ESUC) than ESU alone. The critical role of the buffer in enhancing uricolytic activity of UCU in single or complex alkaline enzymosomes was systematically investigated. The favorable microenvironment is conducive to establishing the best single/complex alkaline enzymosomes with markedly improved stabilities and therapeutic efficacies of an enzyme UCU. The UCU single/ complex enzymosomes in the right buffer significantly can enhance the enzymatic activity, and this has great clinical significance in reducing UCU dosage and adverse enzyme events while increasing the clinical efficacy. The development of single/ complex alkaline UCU enzymosomes in suitable buffers provides valuable tactics in hypouricemic therapy and enzymosomal application

Methods

Results

Conclusion