Combining MPTP mouse experiments and GEO-based bioinformatics, the paper shows ACE2 deficiency worsens dopaminergic neuron loss, α-synuclein–linked neuroinflammation and lung fibrosis via downregulated FoxO1 and upregulated TNF, JAK1-STAT3 and AGE-RAGE pathways, and it nominates diagnostic hub…

The work links a clear, targetable mechanistic axis (ACE2→FoxO1/TNF/JAK1-STAT3/AGE-RAGE) to both neurodegeneration and pulmonary fibrosis, offering actionable biomarkers and drug-repurposing leads that could accelerate therapeutic strategies for PD patients with respiratory comorbidity.

Pulmonary fibrosis is a common and life-threatening complication of Parkinson's disease (PD), yet the molecular mechanisms linking the two diseases remain unclear, creating a critical gap in targeted therapeutic strategies for comorbid patients. Angiotensin-converting enzyme 2 (ACE2) plays a key role in neuroprotection and lung homeostasis; its deficiency exacerbates PD-related neuroinflammation and α-synuclein aggregation, while also promoting pulmonary inflammation and fibrotic remodeling. Clarifying how ACE2 deficiency drives PD-exacerbated pulmonary fibrosis is therefore an urgent unmet need. This study explored the underlying mechanisms using MPTP-induced PD mouse models and bioinformatics analyses of PD/idiopathic pulmonary fibrosis (IPF) datasets from the GEO database. In MPTP-induced PD mice, ACE2 deficiency significantly worsened motor/non-motor dysfunction, dopaminergic neuron loss, microglial/astrocytic activation, and lung fibrosis (evidenced by elevated α-SMA/TGF-β and increased collagen deposition). Bioinformatics identified 41 overlapping differentially expressed genes (DEGs) between PD and IPF, enriched in critical pathways: downregulated FoxO1 (impairing antioxidant defense) and upregulated TNF, JAK1-STAT3, and AGE-RAGE (amplifying inflammation/fibrosis). ROC analysis validated hub genes (e.g., BDNF, FOSL2) with good diagnostic value (AUC > 0.7), and molecular docking identified Smilagenin, Fostamatinib, Olopatadine, and Amlexanox as potential therapeutics. This study confirms ACE2 deficiency is a central driver of PD-exacerbated pulmonary fibrosis via the FoxO1/TNF/JAK1-STAT3/AGE-RAGE pathways, providing novel biomarkers and drug candidates to address the clinical need for managing this comorbidity.