Preparation of Plasma Membrane Vesicles from Bone Marrow Mesenchymal Stem Cells for Potential Cytoplasm Replacement Therapy

We have previously reported on the generation of plasma membrane vesicles (PMVs) through the mechanical extrusion of mammalian cells. The fusion of PMVs ...

Shantou University

The objective of this study was to determine if plasma membrane vesicles (PMVs) could be exploited for efficient transfer of macro-biomolecules and mitochondria. PMVs were derived from mechanical extrusion, and made fusogenic (fPMVs) by incorporating the glycoprotein G of vesicular stomatitis virus (VSV-G). Confocal microscopy examination revealed that cytoplasmic proteins and mitochondria were enclosed in PMVs as evidenced by tracing with cytoplasmically localized and mitochondria-targeted EGFP, respectively. However, no fluorescence signal was detected in PMVs from cells whose nucleus was labeled with an EGFP-tagged histone H2B. Consistently, qRT-PCR measurement showed that mRNA, miRNA and mitochondrial DNA decreased slightly; while nuclear DNA was not measureable. Further, Western blot analysis revealed that cytoplasmic and membrane-bound proteins fell inconspicuously while nuclear proteins were barely detecsle. In addition, fPMVs carrying cytoplamic DsRed proteins transduced about ~40 % of recipient cells. The transfer of protein was further confirmed by using the inducible Cre/loxP system. Mitochondria transfer was found in about 20 % recipient cells after incubation with fPMVs for 5 h. To verify the functionalities of transferred mitochondria, mitochodria-deficient HeLa cells (Rho0) were generated and cultivated with fPMVs. Cell enumeration demonstrated that adding fPMVs into culture media stimulated Rho0 cell growth by 100 % as compared to the control. Lastly, MitoTracker and JC-1 staining showed that transferred mitochondria maintained normal shape and membrane potential in Rho0 cells. This study established a time-saving and efficient approach to delivering proteins and mitochondria by using fPMVs, which would be helpful for finding a cure to mitochondria-associated diseases. Graphical abstract Schematic of the delivery of macro-biomolecules and organelles by fPMVs. VSV-G-expressing cells were extruded through a 3 μm polycarbonate membrane filter to generate fusogenic plasma membrane vesicles (fPMVs), which contain bioactive molecules and organelles but not the nucleus. fPMVs can be endocytosed by target cells, while the cargo is released due to low-pH induced membrane fusion. These nucleus-free fPMVs are efficient at delivery of cytoplasmic proteins and mitochondria, leading to recovery of mitochondrial biogenesis and proliferative ability in mitochondria-deficient cells.

Incorporation of VSV-G produces fusogenic plasma membrane vesicles capable of efficient transfer of bioactive macromolecules and mitochondria.

We previously found niacin receptor GPR109A was expressed in murine islet beta-cells, and signaling through GPR109A inhibited glucose stimulated insulin secretion (GSIS). However, the expression of GPR109A in human islets and its functional relevance is still not known.

Niacin receptor GPR109A inhibits insulin secretion and is down-regulated in type 2 diabetic islet beta-cells.

The objective of this study was to formulate a novel gene delivery system based on the erythrocyte ghost (EG) integrated with fusogenic viral glycoprotein vesicular stomatitis virus glycoprotein G (VSV-G). VSV-G proteins were harvested as condition medium of Ad293 cells carrying a VSV-G transgene and then incorporated into EG. Plasmid DNA was condensed by various transfection reagents. A luciferase expression construct (pGL3-control) and a DsRed expression cassette (pCMV-DsRed) were used to evaluate the delivery efficiency of DNA/EG/VSV-G complexes. VSV-G proteins could be incorporated into EG in static incubation under acidic conditions as evidenced by the Western blot analysis. Condensed plasmid DNA was bound mostly to the outer surface of EG, which could be detected by electromicroscopy and measured by electrophoresis. EG/VSV-G complexes stimulated the delivery of pGL3-control into Ad293 cells significantly with the luciferase activity increased about 4-fold as compared to that of the control. The delivery of pCMV-DsRed was also enhanced with the percentage of DsRed-positive Ad293 cells increased from 55 % to about 80 %. Moreover, the transfection efficiency in 3T3, HeLa, INS-1, and bone marrow stem cell (BMSC) cells increased about 2-3-fold. Finally, confocal microscopy analysis showed that incorporation of VSV-G significantly enhanced the endocytosis of EG into target cells. In the present study, a novel type of non-viral DNA delivery vehicle consisting of EG and fusogenic VSV-G proteins was formulated, which showed superior transfection efficiency even in cells resistant to classical transfection.

Incorporation of Viral Glycoprotein VSV-G Improves the Delivery of DNA by Erythrocyte Ghost into Cells Refractory to Conventional Transfection.

Vesicular stomatitis virus G glycoprotein (VSV-G) has been widely used for pseudotyping retroviral, lentiviral and artificial viral vectors. The objective of this study was to establish a potential approach for large scale production of VSV-G. To this end, VSV-G was cloned with a N-terminal His-tag into Pichia pastoris expression vector pPIC3.5K. Three clones (Mut(s)) containing the VSV-G expression cassette were identified by PCR. All clones proliferated normally in expansion medium, while the proliferation was reduced significantly under induction conditions. VSV-G protein was detected in cell lysates by Western Blot, and the highest expression level was observed at 96 h post induction. VSV-G could also be obtained from the condition medium of yeast protoplasts. Further, VSV-G could be incorporated into Ad293 cells and was able to induce cell fusion, leading to the transfer of cytoplasmic protein. Finally, VSV-G mediated DNA transfection was assayed by flow cytometry and luciferase measurement. Incubation of VSV-G lysate with pGL3-control DNA complex increased luciferase activity in Ad293 and HeLa cells by about 3-fold. Likewise, incubation of VSV-G lysate with pCMV-DsRed DNA complex improved transfection efficiency into Ad293 by 10% and HeLa cells by about 1-fold. In conclusions, these results demonstrated that VSV-G could be produced from Pichia pastoris with bio-functionalities, demonstrating large scale production of the viral glycoprotein is feasible.

Yun-pan Li

Multidisciplinary Research Center

Shantou University

Preparation of Plasma Membrane Vesicles from Bone Marrow Mesenchymal Stem Cells for Potential Cytoplasm Replacement Therapy

Yun-pan Li

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Multidisciplinary Research Center

Shantou University

Preparation of Plasma Membrane Vesicles from Bone Marrow Mesenchymal Stem Cells for Potential Cytoplasm Replacement Therapy

Multidisciplinary Research Center