Proteomic analysis of 3-MCPD and 3-MCPD dipalmitate-induced toxicity in rat kidney

Abstract

3-Chloropropane-1,2-diol (3-MCPD) and its fatty acid esters are formed during thermal treatment of fat-containing foodstuff in the presence of salt. Toxicological studies indicate a carcinogenic potential of 3-MCPD, pointing to the kidney as the main target organ. It is assumed that the toxicological property of 3-MCPD esters is constituted by the release of 3-MCPD during digestion. In a repeated-dose 28-day oral toxicity study using Wistar rats, animals were treated with equimolar doses of either 3-MCPD (10 mg/kg body weight) or 3-MCPD dipalmitate (53 mg/kg body weight). A lower dose of 3-MCPD dipalmitate (13.3 mg/kg body weight) was also applied. No histopathologically visible toxicity was observed in the study. To address molecular mechanisms leading to toxicity of 3-MCPD and its esters, kidney samples were analyzed by a comparative, two-dimensional gel electrophoresis/mass spectrometry proteomic approach. After either 3-MCPD or 3-MCPD dipalmitate treatment, alterations in proteins related to various metabolic pathways, including carbohydrate, amino acid, and fatty acid metabolism, were detected. These findings confirm and complement previous data on the inhibition of glucose metabolism by 3-MCPD. Altogether, broad overlap of 3-MCPD- and 3-MCPD dipalmitate-induced proteomic changes was observed. Further analyses revealed that the observed induction of glutathione S-transferase pi 1 (Gstp1) occurred at the transcriptional level and was not related to nuclear factor (erythroid-derived 2)-like 2 activation. Overall, the results indicate common mechanisms of toxicity for 3-MCPD and its dipalmitate ester. Furthermore, data suggest Gstp1 as a sensitive marker for early 3-MCPD-induced effects in rat kidney.

Comparative proteomic analysis of silver nanoparticle effects in human liver and intestinal cells

“…MALDI‐MS analysis was carried out in duplicate measurement in PMF and LIFT mode on an Ultraflex II MS (Bruker, Bremen, Germany). Mascot search parameters were as described in Sawada et al () with minor modifications (species: Homo sapiens ). For biostatistical evaluation of deregulated protein spots, freely available tools obtained from biostatistical software R (version 3.2.3; R Development Core Team) and Bioconductor were used.…”

“…Two‐dimensional gel electrophoresis (2‐DE) procedures followed the protocol developed by Gorg et al (). Full details of the experimental workflow are provided in Sawada et al (). In brief, isoelectric focusing was performed using 24 cm immobilized pH gradient gel strips loaded with 150 μg protein (in‐gel sample rehydration; for running conditions please refer to Gorg et al, ).…”

“…Four gels were run for each sample and a total of 100 2‐DE gels were processed (four technical and five biological replicates, four treatments plus control). Gel imaging and image analysis was conducted according to Sawada et al ().…”

“…In brief, a robotic spot picker was used for removal of differentially expressed spots from the gels. Tryptic digestion was performed using a published approach (Sawada et al, ). MALDI‐MS analysis was carried out in duplicate measurement in PMF and LIFT mode on an Ultraflex II MS (Bruker, Bremen, Germany).…”

“…MALDI-MS analysis was carried out in duplicate measurement in PMF and LIFT mode on an Ultraflex II MS (Bruker, Bremen, Germany). Mascot search parameters were as described in Sawada et al (2016) with minor modifications (species:…”