Dissertation
BACTERIAL DOUBLE-LAYERED MEMBRANE VESICLES (DMVS) IN VACCINES AND TARGETED DRUG DELIVERY
Doctor of Philosophy (PhD), Washington State University
01/2018
Handle:
https://hdl.handle.net/2376/117289
Abstract
Extracellular vesicles (EVs) are cell membrane-derived compartments and harness the membrane features of parent cells, thus, having a great potential to become a novel platform of drug carriers. Particularly, bacteria spontaneously release outer membrane vesicles (OMVs) that contain various immunogenic antigens and pathogen associated-molecular pattern molecules. Recent studies show that OMVs have demonstrated the potentials in vaccination and targeted drug delivery but there are several limitations to translate them in clinic, such as their complex compositions, low production (39) and the unstable single-layered membrane structure of OMVs (40). The work presented herein was aimed at developing novel methods to artificially generate membrane vesicles directly from bacteria, so-called bacterial double-layered membrane vesicles (DMVs). We hypothesized that DMVs can be exploited to develop vaccines to prevent bacterium-induced sepsis and deliver anti-cancer therapeutics to tumor tissues via bioengineering bacterial membrane. 1) Firstly, we have developed nitrogen cavitation to efficiently generate DMVs from Pseudomonas aeruginosa. Cryo-TEM images and proteomics analysis of DMVs show that DMVs are made from the parent bacterial cell membrane with a wide range of bacterial antigens. Compared to OMVs, DMVs immunizations have demonstrated the higher potency to prevent Pseudomonas aeruginosa-induced sepsis. The cellular mechanism in the higher protection of DMVs has been investigated, and we find that it is involved with innate and adaptive immunity and unique bio-distribution of DMVs. 2) To selectively deliver anti-cancer drugs into tumor tissues, we bioengineered Escgherichia Coli to express a tumor-targeted ligand on membrane followed by making DMVs using nitrogen cavitation. In this work, we can remotely load doxorubicin (an anti-cancer drug) into DMVs made from RGD-engineered bacteria. The tumor vasculature highly expresses αvβ3 integrin that binds to RGD. In the B16BL6 melanoma mouse model, we have demonstrated that our DMVs prevented tumor growth compared to free drug.
Collectively, our work reveals that DMVs generated via nitrogen cavitation have similar properties to OMVs (naturally made from bacteria) but exhibit the higher potency in vaccination. Furthermore, we have developed a new cancer targeted therapy based on DMVs. Our studies demonstrate that DMVs would be a novel platform for vaccine development and cancer targeted therapy.
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Details
- Title
- BACTERIAL DOUBLE-LAYERED MEMBRANE VESICLES (DMVS) IN VACCINES AND TARGETED DRUG DELIVERY
- Creators
- Sihan Wang
- Contributors
- Zhenjia Wang (Advisor)Zhenjia Wang (Committee Member)Philip Lazarus (Committee Member)Santanu Bose (Committee Member)Hui Zhang (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- College of Pharmacy and Pharmaceutical Sciences
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 176
- Identifiers
- 99900581506101842
- Language
- English
- Resource Type
- Dissertation