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Volume 3, Issue 4 (Suppl)
Polym Sci
ISSN: 2471-9935 Polym Sci, an open access journal
October 12-13, 2017 Osaka, Japan
Annual Meeting on
Biopolymers and Drug Delivery Systems
Biopolymers Meeting 2017
October 12-13 2017
Page 60
Polym Sci 2017, 3:4
DOI: 10.4172/2471-9935-C1-006
Efficient delivery of structurally diverse protein cargo into mammalian cells by a bacterial toxin
Anick Auger
1
, Minyoung Park
2
, Greg L Beilhartz
2
and Roman A Melnyk
2
1
Inception Sciences, Canada
2
The Hospital for Sick Children, Canada
G
iven the vast array of applications for protein-based tools and therapeutics inside cells, there is great interest in developing
safe and efficient protein delivery platforms that direct biologics into cells. To date, numerous approaches been investigated
to facilitate protein entry into the cytoplasm of cells, however, though each capable of delivering protein cargo into cells to varying
degrees, general mechanism-based limitations exist for these platforms. In particular, selectivity and/or efficiency remain elusive
features for most platforms owing to their shared nonspecific mode of interaction with membranes. Protein toxins, which use host
cell-surface receptors to initiate entry into cells, are attractive vectors to consider given their natural tendency to delivery proteins into
specific cells with high efficiency. The paucity of development efforts for toxins as protein delivery vectors stem from early studies,
which suggested that delivery was restricted to a select few cargo that were largely unfolded prior to translocation and that the cargo
itself greatly diminished the efficiency of translocation of the system. Through careful engineering of the platform, we show that
neither of these assertions is true. We show that the diphtheria toxin platform is capable of delivering proteins that are over 100 kDa
in size and of varying structures and stability with exquisite efficiency. In fact, to our surprise, we found that diphtheria toxin could
deliver the hyper-stable passenger protein mCherry, which we calculated to have a melting temperature greater than 90 degrees under
the translocation conditions, suggesting that even folded proteins could be delivered into cells. Through a rigorous set of experiments
we trace the misleading early results to effect of cargo on the readout of translocation, rather than the efficiency of translocation. We
also provide functional evidence that the delivered cargo is functional. Using a-amylase as cargo we show that cytosolic glycogen is
degraded in a dose and time dependent manner.
roman.melnyk@sickkids.ca