Hypoxia-preconditioned dental pulp stem cells alleviate acetaminophen-induced liver failure via promoting MYC-HIF1A/HIF-1α-BNIP3-mediated mitophagy.

Abstract

Acetaminophen (APAP)-induced acute liver injury (AILI) is a prevalent clinical liver condition caused mostly by oxidative stress and mitochondrial damage. Dental pulp stem cells (DPSCs) possess antioxidant, anti-inflammatory, and immunomodulatory capabilities, demonstrating significant potential in liver diseases. However, during in vitro culture, they are typically maintained under normoxic conditions (21% O2), which is very different from the hypoxic oxygen level that is found in vivo. It remains unclear whether hypoxic-conditioned dental pulp stem cells (Hyp-DPSCs) exhibit superior therapeutic effects compared to normoxic-conditioned dental pulp stem cells (Nor-DPSCs). This study demonstrated that 24-h exposure to 1% O2 significantly enhanced HIF1A/HIF-1α expression in DPSCs. It promoted mitophagy through the MYC-HIF1A-BNIP3 pathway, enhancing mitochondrial shape and function while reducing oxidative stress in DPSCs. Furthermore, in vitro and in vivo experiments demonstrated that Hyp-DPSCs were far more potent than Nor-DPSCs in boosting the expression of hepatic antioxidant factors and enhancing macroautophagy/autophagy to reduce AILI. These findings revealed that hypoxia activated mitophagy in DPSCs, enhancing their therapeutic efficacy against AILI and providing a novel strategy for stem cell-based AILI treatment.Abbreviations: AILI: acetaminophen-induced acute liver injury; ANOVA: analysis of variance; APAP: acetaminophen; BAX: BCL2 associated X, apoptosis regulator; BCL2: BCL2 apoptosis regulator; BNIP3: BCL2 interacting protein 3; BNIP3L: BCL2 interacting protein 3 like; CASP3: caspase 3; CAT: catalase; CCK-8: cell counting kit-8; CM: conditioned medium; COX4I1: cytochrome c oxidase subunit 4I1; CPT1A: carnitine palmitoyltransferase 1A; CQ: chloroquine; DPSCs: dental pulp stem cells; ELISA: enzyme-linked immunosorbent assay; GO: Gene Ontology; GOT1/AST: glutamic-oxaloacetic transaminase 1; GPT/ALT: glutamic - pyruvic transaminase; GPX4: glutathione peroxidase 4; GSH: glutathione; Hyp-DPSCs: hypoxic-conditioned dental pulp stem cells; H&E: hematoxylin and eosin; HIF1A/HIF-1α: hypoxia inducible factor 1 subunit alpha; HMOX1/HO-1: heme oxygenase 1; HUVECs: human umbilical vein endothelial cells; IF: immunofluorescence; IHC: immunohistochemistry; IL1B/IL-1β: interleukin 1 beta; IL6: interleukin 6; i.p.: intraperitoneally; i.v.: intravenous injection; KEGG: Kyoto Encyclopedia of Genes and Genomes; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MSCs: mesenchymal stem cells; MYC: MYC proto-oncogene, bHLH transcription factor; NAC: N-acetylcysteine; NAPQI: N-acetyl-p-benzoquinone imine; NFE2L2/NRF2: NFE2 like bZIP transcription factor 2; Nor-DPSCs: normoxic-conditioned dental pulp stem cells; PRKN/parkin: parkin RBR E3 ubiquitin protein ligase; PLIN2: perilipin 2; PINK1: PTEN induced kinase 1; PPARA/PPARα: peroxisome proliferator activated receptor alpha; PPARG/PPARγ: peroxisome proliferator activated receptor gamma; ROS: reactive oxygen species; SEM: standard error of the mean; SOD1: superoxide dismutase 1; SQSTM1/p62: sequestosome 1; TEM: transmission electron microscopy; TNF/TNF-α: tumor necrosis factor; TOMM20: translocase of outer mitochondrial membrane 20; VDAC1: voltage dependent anion channel 1; WB: western blot.

Key Findings

• Hypoxia (1% O2) exposure significantly enhances HIF1A/HIF-1α expression in dental pulp stem cells (DPSCs).
• Hypoxia promotes mitophagy through the MYC-HIF1A-BNIP3 pathway, improving mitochondrial function and reducing oxidative stress in DPSCs.
• Hypoxia-preconditioned DPSCs exhibit superior therapeutic effects compared to normoxic DPSCs in reducing acetaminophen-induced acute liver injury by boosting hepatic antioxidant factors and enhancing autophagy.

Clinical Significance

Citation

Li Junyi, Yang Qianyu, Pang Pengchenget al.. Hypoxia-preconditioned dental pulp stem cells alleviate acetaminophen-induced liver failure via promoting MYC-HIF1A/HIF-1α-BNIP3-mediated mitophagy. Autophagy. 2026-Jul-05.