ATF3 attenuates cyclosporin A-induced nephrotoxicity by downregulating CHOP in HK-2 cells

Area of Science:

• Nephrology
• Molecular Biology
• Cell Biology

Background:

• Calcineurin inhibitors like cyclosporin A (CsA) are crucial for preventing organ transplant rejection.
• CsA use is limited by its significant nephrotoxicity, necessitating a deeper understanding of its mechanisms.
• Kidney dysfunction is a major complication associated with CsA treatment.

Purpose of the Study:

• To elucidate the molecular mechanisms underlying CsA-induced nephrotoxicity.
• To investigate the role of endoplasmic reticulum (ER) stress and apoptosis in CsA-mediated kidney damage.
• To identify potential protective factors against CsA nephrotoxicity.

Main Methods:

• Utilized a human embryonic kidney cell line (HK-2) for in vitro studies.
• Performed microarray-based whole-genome expression analysis to assess gene expression changes.
• Investigated the role of specific proteins (ATF3, CHOP) using knockdown experiments.
• Assessed reactive oxygen species (ROS) production and cell death markers.

Main Results:

• CsA treatment induced ER stress and apoptosis-related gene expression in HK-2 cells.
• ER stress led to G1 phase cell-cycle arrest in CsA-exposed cells.
• An inverse relationship was observed between ATF3 and CHOP expression.
• ATF3 knockdown exacerbated CsA-induced CHOP upregulation, ROS production, and cell death.

Conclusions:

• ER stress plays a critical role in CsA-induced nephrotoxicity and apoptosis.
• Activating transcription factor 3 (ATF3) acts as a protective factor against CsA nephrotoxicity.
• ATF3 attenuates CsA-induced kidney damage by downregulating CHOP and ROS production mediated by ER stress.