Deregulated Nrf2-Keap1-BACH1 axis in autism spectrum disorder

Abstract

Autism Spectrum Disorder (ASD) is a group of neurodevelopmental disorders characterized by impairments in social communication, restricted interests, and repetitive behaviors. Although its etiology remains incompletely understood, increasing evidence suggests a multifactorial origin involving genetic alterations, immune dysregulation, and environmental exposures. The aim of this study was to investigate the redox-sensitive Nrf2 signaling pathway in primary dermal fibroblasts isolated from ASD patients. Our results revealed constitutive activation of Nrf2, accompanied by reduced expression of its downstream target heme oxygenase-1 (HO1) and marked nuclear accumulation of the transcriptional repressor BACH1 in ASD cells. Moreover, ASD fibroblasts failed to increase Nrf2 nuclear translocation upon sulforaphane (SFN) stimulation, a response consistent with elevated basal levels of Keap1, a negative regulator that sequesters Nrf2 in the cytoplasm. Notably, treatment with hemin, known to induce nuclear export and degradation of BACH1, successfully restored HO1 gene and protein expression and ameliorated impaired mitochondrial function in ASD fibroblasts, as suggested by the decrease of mtROS levels and the restored mitochondrial membrane potential. Collectively, these results identify a dysregulation of the Nrf2-Keap1-BACH1 axis in ASD and suggest that pharmacological targeting of this pathway may offer therapeutic potential to correct the redox imbalance associated with the disorder.