Crosstalk between oxidative stress, mitochondrial dysfunction, chromosome instability, and the activation of the cGAS-STING/IFN pathway in systemic sclerosis

Abstract

Systemic sclerosis (SSc) is an autoimmune disorder characterized by fibrosis, vascular dysfunction, and immune dysregulation. Recent studies have highlighted the crucial role of cellular stress responses and their connection to innate immunity in SSc pathogenesis, particularly the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) signaling pathway, which has emerged as a pivotal mediator. In SSc, cGAS detects cytosolic DNA and activates STING, triggering type I interferon production and proinflammatory responses. Errors in chromosome segregation, leading to chromosomal instability (CIN) and micronucleus formation, are major contributors to cytosolic DNA release. Additionally, mitochondrial dysfunction in response to stress signaling leads to the release of mitochondrial DNA (mtDNA) into the cytoplasm, further enhancing cGAS-STING activation, although this mechanism requires further validation. Furthermore, mitochondrial impairment leads to excessive production of reactive oxygen species (ROS), which cleave chromosomal DNA and oxidize mtDNA, contributing to chronic inflammation and fibrosis. Alterations in inflammasome and endosome pathways further amplify interleukin and type I interferon responses. This review highlights the crosstalk between mitochondria, ROS, chromosomal missegregation, and the cGAS-STING pathway in SSc pathogenesis. We also discuss emerging therapeutics targeting the cGAS-STING pathway, which hold promise for regulating disease progression and improving outcomes for SSc patients. Although most evidence remains preclinical and long-term outcome data are scarce, this review underscores the potential of emerging therapeutic strategies and emphasizes the importance of personalized approaches. Further research into the molecular signatures of this pathway in SSc could pave the way for precision medicine strategies in the clinical management of this disease.