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

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.

Clodronate liposomes reduce excessive scar formation in a mouse model of burn injury by reducing collagen deposition and TGF-ß1 expression.

Clodronate liposome injection is an effective approach to selectively and specifically depleting macrophages. Macrophages play a crucial role in cutaneous wound healing and are associated with excessive scar formation. Use of clodronate liposomes to enhance cutaneous wound healing and reduce scar formation could represent a major advance in wound therapy and hypertrophic scar treatment. This study aimed to investigate the effects of subcutaneous or intraperitoneal injection of clodronate liposomes on cutaneous wound healing and scar formation. A burn injury mouse model was used. Mice were treated with subcutaneous or intraperitoneal injection of clodronate liposomes. Wound healing time was analyzed and scar tissues were harvested for hematoxylin and eosin (HE) staining, reverse transcription polymerase chain reaction (RT-PCR) and Western blot analyses. Wound healing time in treated mice was extended. HE showed that the basal layer of the epidermis in treated scars was flattened, the dermis layer was not significantly thickened, and collagen fibers were well arranged, with few cells and micro vessels. RT-PCR and Western blot analyses showed that the levels of TGF-ß1 and collagen I-α2 were decreased in treated mice. Clodronate liposomes reduce excessive scar formation and delay cutaneous wound healing possibly by reducing collagen deposition and macrophage-derived TGF-ß1 expression.