Identification of ARNT-regulated BIRC3 as the target factor in cadmium renal toxicity

• Published in: Scientific reports Vol. 7; no. 1; pp. 17287 - 16
• Main Authors: Lee, Jin-Yong, Tokumoto, Maki, Hwang, Gi-Wook, Lee, Moo-Yeol, Satoh, Masahiko
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 11.12.2017; Nature Publishing Group
• Subjects: 13/2; 13/89; 14/34; 45/61; 631/154/570; 631/92/321; 82/1; Apoptosis; Apoptosis - drug effects; Aryl Hydrocarbon Receptor Nuclear Translocator - genetics; Aryl Hydrocarbon Receptor Nuclear Translocator - metabolism; Baculoviral IAP Repeat-Containing 3 Protein - genetics; Baculoviral IAP Repeat-Containing 3 Protein - metabolism; Cadmium; Cadmium - adverse effects; Cadmium Poisoning - etiology; Cadmium Poisoning - metabolism; Cadmium Poisoning - pathology; Caspase; Caspase 3 - genetics; Caspase 3 - metabolism; Caspase-3; Cells, Cultured; Contaminants; DNA microarrays; Gene expression; Gene Expression Profiling; Gene Expression Regulation - drug effects; Humanities and Social Sciences; Humans; Kidney Tubules, Proximal - drug effects; Kidney Tubules, Proximal - metabolism; Kidney Tubules, Proximal - pathology; Kidneys; multidisciplinary; Science; Science (multidisciplinary); siRNA; Toxicity; Transcription factors
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-17494-9

Cadmium (Cd) is an environmental contaminant that exhibits renal toxicity. The target transcription factors involved in Cd renal toxicity are still unknown. In this study, we demonstrated that Cd decreased the activity of the ARNT transcription factor, and knockdown of ARNT significantly decreased the viability of human proximal tubular HK-2 cells. Microarray analysis in ARNT knockdown cells revealed a decrease in the expression of a number of genes, including a known apoptosis inhibitor, BIRC3, whose gene and protein expression level was also decreased by Cd treatment. Although the BIRC family consists of 8 members, Cd suppressed only BIRC3 gene expression. BIRC3 is known to suppress apoptosis through the inhibition effect on caspase-3. Knockdown of BIRC3 by siRNA as well as Cd treatment increased the level of active caspase-3. Moreover, knockdown of BIRC3 not only triggered cell toxicity and apoptosis but also strengthened Cd toxicity in HK-2 cells. Meanwhile, the activation of caspase-3 by suppression of BIRC3 gene expression was mostly specific to Cd and to proximal tubular cells. These results suggest that Cd induces apoptosis through the inhibition of ARNT-regulated BIRC3 in human proximal tubular cells.