Diethylene glycol (DEG) has produced many mass poisonings that have led to severe acute kidney
injury, peripheral neuropathy, and >800 deaths throughout the world. Although DEG is a health concern in the
US because it is found in easily available consumer products, its toxicity offers a unique aspect in the
relationship between its nephrotoxicity and its neurotoxicity. Because the toxic mechanism is not well
understood, the proposed studies relating the mechanism of the renal damage and that of the peripheral
neuropathy will advance the field by increasing the knowledge of such damage-associated pathways. Our
studies have definitively shown that the metabolite responsible for the renal damage is diglycolic acid (DGA),
however its role in the neuropathy is not established. Mechanistic studies with DGA have shown that it
produces mitochondrial dysfunction as an inhibitor of oxidative phosphorylation leading to ATP depletion and
ultimately cell death. DGA has also been shown to chelate free calcium in a similar strength as known calcium
chelator EGTA. Part of the mechanism of DGA-induced cell death might include chelation of intracellular
calcium, thereby decreasing transport of energy-producing substrates into the mitochondria by the calcium-
regulated protein aralar, which then can explain the decreased production of ATP by the electron transport We
hypothesize that DGA exerts a detrimental change in intracellular calcium homeostasis by chelating
cytosolic calcium stores, thus leading to mitochondrial dysfunction in both the kidney and in
sensorimotor neurons. Development of efficacious therapy to counteract DGA toxicity is needed for better
treatment of DEG poisoning, so this research is critical to determine the mechanism by which DGA is toxic and
to be able to develop and test potential new therapies.
Aim 1 will establish an animal model of the neurotoxicity of DEG and will characterize the toxicity
profile of DGA in the brain and kidney as it pertains to calcium homeostasis and aralar-mediated mitochondrial
dysfunction. Aim 2 will examine the effects of DGA on calcium homeostasis in the renal proximal tubule (HPT)
cell model and kinetically relate these changes to DGA-mediated mitochondrial dysfunction. Aim 3 will relate
alterations by DGA in calcium-related proteins to changes in calcium homeostasis and will examine changes in
aralar levels in HPT cells to test whether such manipulations rescue effects of DGA toxicity. Outcome. These
mechanistic studies will significantly impact the field of kidney and neuronal function by using a unique
toxicological model (DGA accumulation) to assess common mechanisms of toxicity between the two tissues.
These in vivo and in vitro studies will convincingly show that DGA produces organ damage by altering calcium-
regulated uptake of energy substrates thereby leading to inhibition of mitochondrial function. AREA Impact.
This project will offer area undergraduates an excellent research training experience and thus will enhance the
research capacity of the NW Louisiana region.