Involvement of PINK1-related Mitophagy and Necroptosis in TDI-Induced Experimental Asthma

Toluene diisocyanate (TDI) is a prevalent cause of occupational asthma. Although mitophagy contributes to various pulmonary diseases, its role and downstream signaling in TDI-induced asthma remain unclear. In this study, we first utilized BALB/c mice to investigate the effects of TDI exposure on pulmonary injury, mitophagy, and associated regulatory mechanisms. Based on these findings, we constructed an adverse outcome pathway (AOP) network for TDI-induced asthma. Mechanistic connections predicted by the AOP were validated in vitro using PINK1-knockdown bronchial epithelial cells, assessing PINK1-related mitophagy, mitochondrial function, cytosolic mtDNA release, attenuated the increased expression of cGAS/STING pathway-related proteins, and necroptosis. Finally, we predicted potential natural product therapeutics through bioactivity screening and toxicity profiling, targeting key genes implicated in TDI-induced asthma. Integration of in vivo, in vitro, and AOP network analyses indicated that TDI exposure induced airway hyperresponsiveness and pulmonary histopathological changes, along with elevated Th2 cytokine production. This exposure selectively upregulated PINK1 and Parkin expression, without altering levels of BNIP3, NIX, or FUNDC1. PINK1 knockdown mitigated TDI-induced mitophagy-related alterations, restored mitochondrial function, reduced cytosolic mtDNA release, attenuated the increased expression of cGAS/STING pathway-related proteins, and reduced necroptosis. In silico screening predicted β-lapachone, genistein, and apigenin as promising candidate therapeutics for TDI-induced asthma. Overall, PINK1-related mitophagy may contribute to TDI-induced occupational asthma, and natural compounds identified via in silico screening are potential candidates that require further in vitro and in vivo validation of their safety and efficacy.