Echinacoside regulates the IRE1/XBP1 signaling pathway through HSP72 to reduce endoplasmic reticulum stress and improve diabetic kidney disease.

INTRODUCTION

Diabetic kidney disease (DKD), a predominant driver of end-stage renal disease, intimately linked to endoplasmic reticulum stress. Echinacoside (Ech), a naturally derived phenylethanoid glycoside, exhibits diverse pharmacological activities; however, its mechanism of action in ameliorating DKD remains unclear.

OBJECTIVE

To clarify the underlying molecular mechanisms of Ech's therapeutic impact on DKD.

METHODS

DKD models were established using db/db mice and high glucose-induced HK-2 cells. The anti-DKD effects of Ech were systematically evaluated. Kidney proteomic sequencing was employed to screen for potential regulatory proteins, which identified Heat Shock Protein 72 (HSP72) as a core target. The IRE1/XBP1 (UPR) pathway was investigated given the established role of HSP72 as a key molecular chaperone in modulating this signaling cascade. Surface plasmon resonance (SPR), microscale thermophoresis (MST), and molecular dynamics simulations (MD) were utilized to validate interactions between Ech and HSP72. Finally, HSP72 knockdown models were generated in both in vivo and in vitro to conclusively validate Ech mechanism of action.

RESULTS

Ech intervention ameliorated DKD in db/db mice, as evidenced by improved insulin resistance, restored glucolipid metabolic homeostasis, and attenuated kidney injury and fibrosis. Furthermore, it protected HK-2 cells against high glucose-induced cytotoxicity, reactive oxygen species (ROS)-mediated damage, and mitochondrial oxidative stress. Mechanistically, kidney proteomics revealed that Ech markedly upregulated HSP72 expression. SPR, MST, and MD results established HSP72 as a direct target of Ech, and the gene knockdown experiments demonstrated that the therapeutic efficacy of Ech against DKD was significantly abrogated in the absence of HSP72. Through direct interaction with HSP72, Ech activated the IRE1/XBP1 pathway, thereby alleviating endoplasmic reticulum stress, reducing mitochondrial oxidative stress, and suppressing apoptosis, ultimately ameliorating DKD.

CONCLUSION

Our study demonstrates that Ech ameliorates DKD by targeting HSP72 to activate the IRE1/XBP1 pathway, thereby mitigating mitochondrial and endoplasmic reticulum stress and reducing kidney apoptosis. These findings highlight the potential of Ech as a therapeutic agent for DKD.