Plant aquaporin reconstituted proteoliposomes as nanosystem for
resveratrol encapsulation
Abstract
Aquaporins (AQPs) are intrinsic membrane proteins responsible for
facilitating water transport across biological membranes. AQPs found in
plant membrane vesicles (MV) have been related to the functionality and
stability of the vesicles. In this study, we focused on AQPs obtained
from Brassica oleracea var. L. italica (broccoli) by the great potential
for different biotechnological applications. To gain further insight
into the role of AQPs in MV and advance the biotechnological
applications of AQPs, we describe the heterologous overexpression of two
broccoli AQPs (BoPIP1;2 and BoPIP2;2) in Pichia pastoris, resulting in
the purification of both AQPs with high yield (0.14 and 0.99 mg per gram
cells for BoPIP1;2 and BoPIP2;2, respectively). We reconstituted
purified AQPs in liposomes to study their functionality, showing no
changes in size compared to liposomes. BoPIP2;2 facilitated water
transport, which was preserved for seven days at 4oC and 25ºC but not at
37oC, whereas BoPIP1;2 did not enhance water transport across the
proteoliposome membrane. Additionally, BoPIP2;2 was incorporated into
liposomes to encapsulate a resveratrol extract in proteoliposome
vesicles, resulting in increased entrapment efficiency compared to
conventional liposomes. Molecular docking identified potential binding
sites for resveratrol in PIP2s, highlighting the role of AQPs in the
improved entrapment efficiency of resveratrol. Moreover, a modelling
study was conducted, demonstrating interactions between a plant AQP and
human integrin, which may be a benefit to increase contact and
internalization by the human target cells. Thus, our results suggest
that AQPs-based alternative encapsulation systems can be used in
specifically target biotechnological applications.