SIRT-2 inhibition by AK-7 orchestrates fibrotic cascades in airways through neuroimmune interaction via TRPA1, TRPM8 and TGF-β signalling

Chronic obstructive pulmonary diseases (COPD) is characterized by airflow limitation, chronic inflammation and airway remodeling (AR) in airways and lung parenchyma. AR, a lung response, involves mucus production, airflow issues, and structural changes. It is exacerbated by neurogenic inflammation from activated sensory nerves, highlighting the interplay between neuronal and immune regulation in COPD. Sirtuins play a crucial role in lung remodeling, with SIRT-2 being the least studied. Present study explores how SIRT-2 regulates neurogenic inflammation and fibrosis in experimental BALB/c mice with cigarette smoke-induced COPD. Mice from each group, except the control, were exposed to CS for 60 days and AK-7 (100ug/kg and 200ug/kg) was administered intranasally. The study evaluated lung injury and inflammation marked by increased Cortisol, ACTH, COX-2 and LDH in COPD group with its attenuation by SIRT-2 inhibition. Additionally, CS exposure exhibited neurogenic inflammation represented by activated TPRV1 and TRPM8, elevated neuromediators levels (dopamine, acetylcholine, substance P, serotonin) and their respective receptors which were mitigated by AK-7. CS exposure enhanced fibrosis by targeting the fibrotic cascade, enhancing MMP-9, total collagen, hydroxyproline, and upregulating αSMA, MUC5AC, TGF-β, PKA, GATA-3, FOXO3, and STAT-6. SIRT-2 inhibition effectively reversed all these factors suppressing fibrosis further supported by downregulated SIRT-2 expression and histopathological studies where collagen deposition and mucus production were also attenuated by AK-7. Molecular docking revealed strong binding affinity of certain protein such as COX-2, D5DR and 5HT with AK-7. Overall, targeting SIRT-2 to modulate neuro-immune interplay presents a promising therapeutic approach for addressing AR in COPD.