The urine proteome for radiation biodosimetry: effect of total body vs. local kidney irradiation

Abstract

Victims of nuclear accidents or radiological terrorism are likely to receive varying doses of ionizing radiation inhomogeneously distributed over the body. Early biomarkers may be useful in determining organ-specific doses due to total body irradiation (TBI) or partial body irradiation. The authors used liquid chromatography and mass spectrometry to compare the effect of TBI and local kidney irradiation (LKI) on the rat urine proteome using a single 10-Gy dose of x-rays. Both TBI and LKI altered the urinary protein profile within 24 h with noticeable differences in gene ontology categories. Some proteins, including fetuin-B, tissue kallikrein, beta-glucuronidase, vitamin D-dependent calcium binding protein and chondroitin sulfate proteoglycan NG2, were detected only in the TBI group. Some other proteins, including major urinary protein-1, RNA binding protein 19, neuron navigator, Dapper homolog 3, WD repeat and FYVE domain containing protein 3, sorting nexin-8, ankycorbin and aquaporin were detected only in the LKI group. Protease inhibitors and kidney proteins were more abundant (fraction of total scans) in the LKI group. Urine protein (Up) and creatinine (Uc) (Up/Uc) ratios and urinary albumin abundance decreased in both TBI and LKI groups. Several markers of acute kidney injury were not detectable in either irradiated group. Present data indicate that abundance and number of proteins may follow opposite trends. These novel findings demonstrate intriguing differences between TBI and LKI, and suggest that urine proteome may be useful in determining organ-specific changes caused by partial body irradiation.

Fig. 1

The Venn diagram presents an overview of LC-MS/MS results. These numbers are derived from raw protein counts. About one third of all proteins (28.9%) were present in all groups. Proteins uniquely present in the Control, TBI and LKI groups were 20.1%, 10.2% and 25.0%, respectively. Differences between the TBI and LKI groups suggest tissue-specific effects of ionizing radiation.

Fig. 2

Fig. 2A. Proteins assigned to cellular compartments extracellular spaces, various membrane compartments, nucleus, lysosomes, endoplasmic reticulum, actin filament, cytosol, plasma membrane, intermediate filament, soluble fraction and golgi stack were most abundant in all groups and higher in the Control group compared with the TBI or LKI groups. Fig. 2B. Proteins assigned to molecular functions transporter activity, pheromone binding, growth factor binding, epidermal growth factor receptor binding, heme binding were in the order LKI > Control > TBI. Proteins assigned molecular functions hydrolase activity, alpha amylase activity, glycosyl binding, endopeptidase activity, actin binding and structural molecule binding activity were in the order TBI > LKI > Control. Fig. 2C. Proteins assigned to biological process transport, Type 1 hypersensitivity, oxygen transport, iron ion homeostasis and glutathione biosynthesis were in the order LKI > TBI > Control.

Fig. 2

Fig. 2A. Proteins assigned to cellular compartments extracellular spaces, various membrane compartments, nucleus, lysosomes, endoplasmic reticulum, actin filament, cytosol, plasma membrane, intermediate filament, soluble fraction and golgi stack were most abundant in all groups and higher in the Control group compared with the TBI or LKI groups. Fig. 2B. Proteins assigned to molecular functions transporter activity, pheromone binding, growth factor binding, epidermal growth factor receptor binding, heme binding were in the order LKI > Control > TBI. Proteins assigned molecular functions hydrolase activity, alpha amylase activity, glycosyl binding, endopeptidase activity, actin binding and structural molecule binding activity were in the order TBI > LKI > Control. Fig. 2C. Proteins assigned to biological process transport, Type 1 hypersensitivity, oxygen transport, iron ion homeostasis and glutathione biosynthesis were in the order LKI > TBI > Control.

Fig. 2

Fig. 2A. Proteins assigned to cellular compartments extracellular spaces, various membrane compartments, nucleus, lysosomes, endoplasmic reticulum, actin filament, cytosol, plasma membrane, intermediate filament, soluble fraction and golgi stack were most abundant in all groups and higher in the Control group compared with the TBI or LKI groups. Fig. 2B. Proteins assigned to molecular functions transporter activity, pheromone binding, growth factor binding, epidermal growth factor receptor binding, heme binding were in the order LKI > Control > TBI. Proteins assigned molecular functions hydrolase activity, alpha amylase activity, glycosyl binding, endopeptidase activity, actin binding and structural molecule binding activity were in the order TBI > LKI > Control. Fig. 2C. Proteins assigned to biological process transport, Type 1 hypersensitivity, oxygen transport, iron ion homeostasis and glutathione biosynthesis were in the order LKI > TBI > Control.

Fig. 3

Proteases and protease inhibitors in Control, LKI and TBI groups are presented as percent of total scans. Proteases were detected in the order Control > LKI > TBI. Protease inhibitors were detected in the order TBI > Control ≥LKI. Increased abundance of protease inhibitors suggests activation of proteases in the blood.

Fig. 4

Proteins grouped as kidney proteins, kidney injury proteins, acute phase proteins and major urinary protein based on UniProt classification are shown. Kidney proteins in the LKI group were significantly different from Control (P<0.001 vs. LKI) and TBI groups (P<0.001 vs. LKI). MUP in the LKI was significantly increased compared with Control (P<0.05). Kidney injury proteins and acute phase proteins constituted very small fractions of the total.

Fig. 5

The protein count (protein number) of proteases, protease inhibitors and kidney proteins increased in the urine proteome following irradiation in the order TBI > LKI Control.