The trypanocidal benznidazole promotes adaptive response to oxidative injury: Involvement of the nuclear factor-erythroid 2-related factor-2 (Nrf2) and multidrug resistance associated protein 2 (MRP2)

Abstract

Oxidative stress is a frequent cause underlying drug-induced hepatotoxicity. Benznidazole (BZL) is the only antitripanocide agent available for treatment of Chagas disease in endemic areas. Its use is associated with side effects, including increases in biomarkers of hepatotoxicity. However, BZL potential to cause oxidative stress has been poorly investigated. Here, we evaluated the effect of a pharmacologically relevant BZL concentration (200 μM) at different time points on redox status and the counteracting mechanisms in the human hepatic cell line HepG2. BZL increased reactive oxygen species (ROS) after 1 and 3 h of exposure, returning to normality at 24 h. Additionally, BZL increased glutathione peroxidase activity at 12 h and the oxidized glutathione/total glutathione (GSSG/GSSG+GSH) ratio that reached a peak at 24 h. Thus, an enhanced detoxification of peroxide and GSSG formation could account for ROS normalization. GSSG/GSSG+GSH returned to control values at 48 h. Expression of the multidrug resistance-associated protein 2 (MRP2) and GSSG efflux via MRP2 were induced by BZL at 24 and 48 h, explaining normalization of GSSG/GSSG+GSH. BZL activated the nuclear erythroid 2-related factor 2 (Nrf2), already shown to modulate MRP2 expression in response to oxidative stress. Nrf2 participation was confirmed using Nrf2-knockout mice in which MRP2 mRNA expression was not affected by BZL. In summary, we demonstrated a ROS increase by BZL in HepG2 cells and a glutathione peroxidase- and MRP2 driven counteracting mechanism, being Nrf2 a key modulator of this response. Our results could explain hepatic alterations associated with BZL therapy.

Drug transporter and oxidative stress gene expression in human macrophages infected with benznidazole-sensitive and naturally benznidazole-resistant Trypanosoma cruzi parasites treated with benznidazole

“…Among these genes, we identified CAT (catalase), GCLC (glutamate-cysteine ligase catalytic subunit), GCLM (glutamate-cysteine ligase modifier subunit), GPX1 (glutathione peroxidase 1), GSR (glutathione reductase), GSS (glutathione synthetase) and GSTP1 (glutathione S-transferase π1) (Additional file 2: Table S2). In contrast to our findings of downregulation of these genes, recent studies have shown enzymatic upregulation of CAT, SOD and GPX as a natural response to attenuate damage mediated by ROS/RNS after 12 h of exposure to BZ [28, 30]. These differences suggest that to evaluate the significance of these results, a strategy combining different time points could elucidate the true involvement of these molecules in host cell responses to BZ treatment.…”

“…Despite the high mRNA expression levels of MRP2 observed in all treated conditions, the results suggest that this transporter may play a role in BZ detoxification. MRP2 has been reported to be involved in xenobiotic efflux, which potentially induces oxidative stress in host cells [28]. Moreover, MRP2 extrudes GSSG, which, along with de novo GSH synthesis, contributes to the return of normal GSH levels and redox homeostasis [28].…”

ROS and Trypanosoma cruzi: Fuel to infection, poison to the heart

“…Although the full mechanism of action of benznidazole remains to be elucidated, these results indicate that ROS are not involved in benznidazole’s trypanocidal effects. Benznidazole also activates nuclear erythroid factor-2 (Nrf2) and protects the host from oxidative damage in a delayed time frame [ 16 ].…”

Chemopreventive effects of atractylenolide II on mammary tumorigenesis via activating Nrf2-ARE pathway

“…Activation of the Nrf2 pathway is a promising strategy for chemoprevention, however, some investigation has revealed that Nrf2 and its downstream detoxifying enzymes are overexpressed in various cancer cell lines and human cancer tissues, giving cancer cells an advantage for survival and growth [ 45 , 46 ]. In addition, Nrf2 is upregulated in multiple drug resistant (MDR) cancer cells, which accounts for the acquired chemoresistance [ 47 , 48 ]. The E2 induced MCF 10A cell model indicated that ATR-II had chemopreventive effects on MCF 10A cells associated with activating the Nrf2-ARE signaling pathway.…”