Abstract: Objective To investigate the role of high mobility group protein 1 (HMGB1) in aldosterone (ALDO) -
induced autophagy of rat renal tubular epithelial cells. Methods Rat renal tubular epithelial cells (NRK-52E) in
logarithmic growth phase were divided into control group, ALDO group (10 nmol/L), HMGB1 antibody group (1 mg/L), IgG
group (1 mg/L), ALDO + HMGB1 antibody group (1 mg/L HMGB1 antibody pretreatment for 1 h, then 10 nmol/L ALDO
stimulation for 24 h) and positive control group (Rosup, 100 µmol/L). After 24 h treatment, the changes of reactive oxygen
species (ROS) levels in NRK-52E cells were detected by flow cytometry after labeling with fluorescent probe DCFH-DA. In
addition, the cultured NRK-52E cells were divided into control group, ALDO group (10 nmol/L), N-acetylcysteine group
(NAC, 50 µmol/L) and NAC+ALDO group (50 µmol/L NAC pretreatment for 1 hour, followed by 10 nmol/L ALDO). The
expression of IL-1β protein was detected by Western blot assay 24 hours after treatment. The expression of HMGB1 protein was observed 24 hours after 10 nmol/L ALDO stimulation.Finally, the expressions of LC3-Ⅱ, Beclin-1 and p62 proteins were detected by Western blot assay after pretreatment with 1 mg/L HMGB1 antibody for 1 hour and stimulation with 10 nmol/L ALDO for 24 hours. Results Flow cytometry showed that ROS production in NRK-52E cells increased significantly
in ALDO group compared with those of control group (P＜0.05). Compared with ALDO group, the intracellular ROS level
decreased significantly in ALDO+HMGB1 antibody group (P＜0.05). Western blot results showed that compared with control
group, the expressions of IL-1β, HMGB1, LC3- Ⅱ and Beclin-1 proteins were up-regulated in ALDO group, and the
expression of p62 protein was down-regulated (P＜ 0.05). Compared with ALDO group, the expression of IL-1β protein was
down-regulated in NAC+ALDO group (P＜0.05), the expression of LC3-Ⅱ protein was down-regulated and the expression
of p62 protein was increased in ALDO+HMGB1 antibody group (P＜0.05). There was no significant difference in the
expression of Beclin-1 protein (P＞0.05). Conclusion ALDO can induce autophagy by promoting ROS production,
increasing the secretion of HMGB1 and stimulating the release of IL-1β in NRK-52E cells. Inhibiting the release of HMGB1
can reverse this phenomenon and provide new targets and ideas for the prevention and treatment of chronic kidney diseases.

Key words: high mobility group proteins, aldosterone, autophagy, chronic kidney disease, renal tubular epithelial cells