Overview
Putting exosomes to work: Target exosomes to specific tissues
Use exosomes to deliver protein, RNA, DNA, or small molecule cargo to specific tissues with XStamp. The patented XStamp technology is an optimized, exosome surface display system that efficiently places protein sequences on exosomal surfaces. When a tissue-specific protein ligand is used, the engineered exosomes become targeted to the specified tissue, enabling directed cargo delivery.
- Display proteins on exosome surfaces
- Coat exosomes with targeting ligands
- Target specific cellular destinations
- Create stable XStamp cell lines
In addition to the XStamp Cloning and Expression Lentivector, SBI also offers a selection of pre-built targeting XStamp Lentivectors:
| Cat.# | Specificity | Targeting Ligand Used |
|---|---|---|
| XSTP710PA-1 | Clone-your-own | You decide |
| XSTP720PA-1 | GI tract cells | Motilin |
| XSTP721PA-1 | Neural cells | NCAM |
| XSTP722PA-1 | Brain cells | BHP1 |
| XSTP723PA-1 | Cancer cells | GE11 |
| XSTP724PA-1 | Breast cancer cells | HER2 |
| XSTP725PA-1 | Antigen-presenting cells | CD40L/CD154 |
| XSTP726PA-1 | Immune cells | IL-2 |
How It Works
Engineering exosomes with specific surface proteins
XStamp is based upon a C-terminal fusion of the C1C2 domain from the protein MFG-E8, which is targeted to the exosome surface. Protein sequences that are fused to the XStamp tag will efficiently display the protein ligand fusion on the surfaces of secreted exosomes.
To target your protein ligand to the exosome surface, simply clone the gene encoding your protein ligand-of-interest into the MCS site of the XStamp Cloning and Expression Vector. Your ligand will have a 5’ secretion signal sequence and a C-term XStamp. The XStamp Lentivector also features a downstream EF1-Puromycin cassette for positive selection and, when packaged into virus, the XStamp Lentivector can be used to create stable cell lines that secrete your engineered exosomes.
Supporting Data
See XStamp targeting in action
Figure 1. XStamp with motilin specifically targets exosomes to GI cells. Motilin is a 22-amino acid polypeptide hormone that binds to the motilin receptor, which is exclusively expressed in the intestine. XStamp with motilin can be used to target exosomes to GI cells. METHODS: The XStamp-Motilin construct (Cat.# XSTP720PA-1) was transfected into HEK293 cells and after 48 hours, the exosomes were isoalted using ExoQuick-TC. The next day, the XStamp-Motilin exosomes were Exo-Fected with a Texas-Red-labeled siRNA to monitor exosome docking and delivery. The transfected XStamp-Motilin exosomes were then added to MDA-MB-231 Breast Cancer Cells (motilin receptor negative) and to HT-29 Colon Cancer Cells (motilin receptor positive). The cells were imaged after 24 hours for uptake of the Texas-Red-labeled siRNA delivery from the XStamped exosomes. The HT-29 colon cancer cells that are motilin receptor positive took up the XStamp-Motilin exosomes at a much higher rate than the MDA-MB-231 Breast Cancer (motilin receptor negative) cells.
