Vivo detection of phospholipase activation
The present invention is directed to a phospholipid-based NIR molecular beacon, having a phospholipid moiety; with an NIR fluorophore moiety covalently linked to a phospholipid glycerol backbone and a quencher moiety covalently linked to the phospholipid glycerol backbone. Additionally, provided herein is methods of analyzing a sample for the presence of a phospholipase and methods of identifying the activity of a phospholipase in vivo utilizing phospholipid-based NIR molecular beacon.
1. A phospholipid-based near infrared (NIR) molecular beacon comprising a phospholipid moiety with a glycerol backbone, a first fluorophore moiety covalently linked to the glycerol backbone of said phospholipid either directly or via a linker, wherein said first fluorophore moiety is an NIR fluorophore moiety, and a fluorescence quencher moiety covalently linked to said phospholipid glycerol backbone either directly or via a linker, wherein the fluorophore moiety, quencher moiety or both are uncharged when covalently linked at either or both sn-1 or sn-2 fatty acyl positions, wherein a change in NIR fluorescence of said NIR fluorophore is detectable upon cleavage of said phospholipid with a phospholipase.
2. The beacon of claim 1 , wherein said NIR fluorophore is covalently bound to the glycerol phosphate backbone at either sn-1 or sn-2 fatty acyl positions or to the sn-3 head group.
3. The beacon of claim 2 , wherein the binding position on the acyl group of said NIR fluorophore is enzyme-specific.
4. The beacon of claim 1 , wherein said NIR fluorophore is pyropheophorbide a, bacteriochlorin or Cy5.5.
5. The beacon of claim 1 , wherein said linker has variable moieties.
6. The beacon of claim 1 , wherein said quencher moiety is black hole quencher 3 (BHQ3) or BlackBerry Quencher 650.
7. The beacon of claim 1 , wherein said phospholipase is phospholipase A1 (PLA1), lysophosphoslipase, phospholipase A2 (PLA2), phospholipase B (PLB), phospholipase C (PLC) or phospholipase D (PLD).
8. The beacon of claim 7 , wherein said PLC is phosphatidylcholine-specific phospholipase C (PC-PLC).
9. The beacon of claim 1 , wherein said phospholipase is phosphatidylinositol-specific PLC (PI-PLC), sphingomyelinase (SMase), PC-specific PLD (PC-PLD), type IA secretory phospholipase A2 (sPLA2) or type IB sPLA2.
10. The beacon of claim 1 , wherein said phospholipid moiety is phosphatidylcholine.
11. A composition comprising the molecular beacons of claim 1 , wherein the molecular beacons are stereospecific at the sn-2 chiral center.
12. The composition of claim 11 , wherein the molecular beacons have an enantiomeric excess greater than 98%.
13. The composition of claim 11 , wherein the stereospecific sn-2 chiral center is the (S) stereoisomer.
14. The composition of claim 11 , wherein the stereospecific sn-2 chiral center is the (R) stereoisomer.