Oxidative stress is a major contributor to kidney injury following
ischemia reperfusion.
Ferritin, a highly conserved
iron-binding protein, is a key
protein in the maintenance of cellular
iron homeostasis and protection from oxidative stress.
Ferritin mitigates
oxidant stress by sequestering
iron and preventing its participation in reactions that generate
reactive oxygen species.
Ferritin is composed of two subunit types,
ferritin H and
ferritin L. Using an in vivo model that enables conditional tissue-specific
doxycycline-inducible expression of
ferritin H in the mouse kidney, we tested the hypothesis that an increased level of H-rich
ferritin is renoprotective in ischemic
acute renal failure. Prior to induction of
ischemia,
doxycycline increased
ferritin H in the kidneys of the transgenic mice nearly 6.5-fold. Following reperfusion for 24 hours, induction of neutrophil gelatinous-associated
lipocalin (NGAL, a urine marker of renal dysfunction) was reduced in the
ferritin H overexpressers compared to controls. Histopathologic examination following
ischemia reperfusion revealed that
ferritin H overexpression increased intact nuclei in renal tubules, reduced the frequency of tubular profiles with
luminal cast materials, and reduced activated
caspase-3 in the kidney. In addition, generation of 4-hydroxy
2-nonenal protein adducts, a measurement of
oxidant stress, was decreased in
ischemia-reperfused kidneys of
ferritin H overexpressers. These studies demonstrate that
ferritin H can inhibit apoptotic cell death, enhance tubular epithelial viability, and preserve renal function by limiting oxidative stress following
ischemia reperfusion injury.