Cytotoxicity of prion protein-derived cell-penetrating peptides is modulated by pH but independent of amyloid formation.
Prion diseases are associated with conversion of cellular prion protein (PrPC) into an abnormally folded and infectious scrapie isoform (PrPSc). We previously showed that peptides derived from the unprocessed N-termini of mouse and bovine prion proteins, mPrP1-28and bPrP1-30,function as cell-penetrating peptides (CPPs), and destabilize model membrane systems, which could explain the infectivity and toxicity of prion diseases. However, subsequent studies revealed that treatment with mPrP1-28or bPrP1-30significantly reduce PrPSclevels in prion-infected cells. To explain these seemingly contradictory results, we correlated the aggregation, membrane perturbation and cytotoxicity of the peptides with their cellular uptake and intracellular localization. Although the peptides have a similar primary sequence, mPrP1-28is amyloidogenic, whereas bPrP1-30forms smaller oligomeric or non-fibrillar aggregates. Surprisingly, bPrP1-30induces much higher cytotoxicity than mPrP1-28, indicating that amyloid formation and toxicity are independent. The toxicity is correlated with prolonged residence at the plasma membrane and membrane perturbation. Both ordered aggregation and toxicity of the peptides are inhibited by low pH. Under non-toxic conditions, the peptides are internalized by lipid-raft dependent macropinocytosis and localize to acidic lysosomal compartments. Our results shed light on the antiprion mechanism of the prion protein-derived CPPs and identify a potential site for PrPScformation.
Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates.
Vineeth
V
Mukundan
Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates.
Christy
C
Maksoudian
Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates.
Maria C
MC
Vogel
Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates.
Ibrahim
I
Chehade
Department of Chemical Engineering, The Petroleum Institute, Abu Dhabi, United Arab Emirates.
Marios S
MS
Katsiotis
Department of Chemical Engineering, The Petroleum Institute, Abu Dhabi, United Arab Emirates.
Saeed M
SM
Alhassan
Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates. Electronic address: mazin.magzoub@nyu.edu.
Mazin
M
Magzoub
D000682:Amyloid / Q000737:chemistry*; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D002470:Cell Survival; D057846:Cell-Penetrating Peptides / Q000737:chemistry*; D011992:Endosomes / Q000737:chemistry / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008081:Liposomes / Q000737:chemistry; D008247:Lysosomes / Q000737:chemistry; D051379:Mice; D046529:Microscopy, Electron, Transmission; D010455:Peptides / Q000737:chemistry; D000072002:Prion Proteins / Q000737:chemistry*; D000072417:Protein Domains; D021382:Protein Sorting Signals; D013696:Temperature
D000682:Amyloid; D057846:Cell-Penetrating Peptides; D008081:Liposomes; D010455:Peptides; D000072002:Prion Proteins; D021382:Protein Sorting Signals
Aggregation; Amyloid; Cell-penetrating peptides; Cytotoxicity; Membrane perturbation; Prion protein