Mitochondrial and autophagic dysfunctions of skin fibroblasts derived from pantothenate kinase-associated neurodegeneration patients carrying PANK2 mutations and the rescuing effects of allantoin

Abstract

Introduction

Pantothenate kinase-associated neurodegeneration (PKAN) is a rare neurodegenerative disorder marked by brain iron accumulation and mitochondrial dysfunction, with limited effective treatments. This study investigates cellular dysfunctions in PKAN fibroblasts with PANK2 mutations and evaluates the therapeutic potential of the antioxidant allantoin for protecting mitochondrial and autophagic functions.

Methods

We investigated oxidative stress, mitochondrial impairment, and autophagic dysfunction in skin fibroblasts derived from PKAN patients carrying mutations in the PANK2 gene and siR-pank2 treated fibroblasts, and evaluates the therapeutic potential of allantoin in mitigating these defects.

Results

Our results revealed significantly elevated levels of H₂O₂ and an increased mitochondrial labile iron pool (LIP), also reduced aconitase 2 (ACO2) activity and mitochondrial membrane potential, suggesting heightened oxidative stress and mitochondrial dysfunction. Autophagic flux was also impaired, as evidenced by the increased LC3-II and p62 accumulation. Allantoin treatment significantly reduced intracellular iron deposition and lipid peroxidation in PANK2-deficient fibroblasts. LIP levels were decreased, and ACO2 activity was elevated in allantoin-treated PANK2 mutant fibroblasts and siRNA-pank2 fibroblasts. Additionally, allantoin treatment promoted autophagic flux by reducing LC3-II and p62 levels.

Conclusion

These findings highlight the key pathological effect of oxidative stress, mitochondrial dysfunction and impaired autophagy in PKAN and suggest a protective role of allantoin in iron deposition via dual regulation of mitochondrial dysfunction and compromised autophagy. The data provides a foundation for future in vivo studies and the potential clinical application of allantoin in PKAN and related neurodegenerative diseases.