SUMO-1 modification of IκBα controls NFκB-mediated
transcription. A, wild type, knockdown, and overexpressing SUMO-1
cells were assayed for IL-6 mRNA transcript levels using real time PCR at
base-line normoxia or after 24 h of hypoxia. Control and SUMO-1 knockdown
cells demonstrated remarkable increase in IL-6 expression in hypoxia
(*, p < 0.005) compared with Normoxic cells.
SUMO-1-overexpressing cells showed impressive attenuation of IL-6 expression
despite hypoxia (**, p < 0.005). B, IL-6 mRNA
levels of whole lung tissue lysates from C57BL/6 or CD 73 null mice exposed to
hypoxia or in vivo protocols of H/R. In wild type mice (WT),
H/R induced attenuation of IL-6 expression (*, p <
0.05, compared with hypoxia) similar to the effect observed in vitro.
In CD 73 (-/-) tissue, the absence of Ado signaling produced a substantial
increase (10-fold; **, p < 0.01) in base-line normoxic
levels of IL-6 and 11-fold (***, p < 0.01, compared
with normoxic WT) increase during hypoxia. C, protein levels of
SUMO-1/IκBα. WT animals exposed to H/R showed restoration of
SUMO-1/IκBα compared with degraded levels in animals exposed to
hypoxia (p < 0.01). Basal levels of SUMO-1/IκBα in CD
73 null mice were substantially lower (p < 0.001) compared with WT
animals and no increase was observed despite H/R.