PGK1 depletion activates Nrf2 signaling to protect human osteoblasts from dexamethasone

Area of Science:

• Biochemistry
• Cell Biology
• Molecular Medicine

Background:

• Dexamethasone (DEX) induces oxidative injury and death in human osteoblasts.
• Nuclear-factor-E2-related factor 2 (Nrf2) signaling cascade activation can protect against this DEX-induced damage.
• Phosphoglycerate kinase 1 (PGK1) inhibition activates Nrf2 signaling via Kelch-like ECH-associated protein 1 (Keap1) modification.

Purpose of the Study:

• To investigate the role of PGK1 depletion in protecting human osteoblasts from DEX-induced oxidative injury.
• To elucidate the underlying mechanism involving the Keap1-Nrf2 signaling pathway.

Main Methods:

• PGK1 silencing using targeted shRNA in OB-6 osteoblastic cells and primary human osteoblasts.
• PGK1 knockout using CRISPR/Cas9 technology.
• Assessment of Nrf2 signaling activation (protein stabilization, nuclear translocation, ARE-dependent gene expression).
• Evaluation of cytoprotection against DEX-induced injury.
• Manipulation of Nrf2 and Keap1 expression to confirm pathway involvement.

Main Results:

• PGK1 silencing or knockout activated the Nrf2 signaling cascade, increasing Nrf2 stabilization and nuclear translocation.
• Activation of Nrf2 led to increased expression of antioxidant genes (HO1, NQO1, GCLC).
• PGK1 depletion significantly attenuated DEX-induced oxidative injury and cell death in osteoblasts.
• The cytoprotective effect of PGK1 depletion was dependent on Nrf2 activation and involved Keap1.
• Downregulation of PGK1 and HO1 was observed in human osteonecrosis tissues from DEX-treated patients.

Conclusions:

• PGK1 depletion protects human osteoblasts against DEX-induced oxidative stress and cell death.
• This protection is mediated through the activation of the Keap1-Nrf2 signaling pathway.
• PGK1 may represent a novel therapeutic target for preventing DEX-induced osteotoxicity.