CAN ICE-BINDING PROTEINS ENHANCE SURVIVAL OF HUMAN EMBRYONIC KIDNEY

• Main Author: Cells After Freezing
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; Antarc*; ice algae; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.542.1480; http://www.ishib.org/journal/18-2s1/ethn-18-02s1-16.pdf

Ice-binding proteins (IBPs) have recently been identified in Antarctic sea-ice algae, cold-adapted fungi, and bacteria. These proteins are known to bind to the surface of ice and inhibit recrystallization. Studies have also shown that these proteins enhance cell survival after freezing and thawing in algal cells and human red blood cells. The objective of this study was to determine if recombinant IBP expression can enhance survival of human embryonic kidney cells (HEK293) following freezing. We hypothesized that HEK293 cells expressing IBPs would result in a higher proportion of live versus dead cells following freezing and thawing. HEK293 cells were stably transfected with IBPs from an Antarctic sea-ice algae (Navicula glaciei), enoki mush-room, or shiitake mushroom. Transfected cell lysates were isolated to confirm IBP activity. Cells were grown to confluence, isolated by trypsin, separated into cryotubes at equal cell density, frozen for 24 hours in liquid nitrogen, thawed, and the percent alive was quantified. Results from two freeze/thaw experiments were not conclusive, although one experiment showed a significantly higher survival in all cells expressing IBPs [expressed as percent mean survival +/2 SE (HEK control: 18.03 % +/2 8.10; shiitake: 39.94 % +/2 1.30; enoki: 48.40 % +/2 3.48; Navicula: 43.27 % +/2 2.87, P,0.05)]. These data suggest that under optimal conditions, IBPs may enhance the survival of mammalian cells when held at low temperatures.