Isoforskolin targets ADCY7 to restore mitochondrial function in COPD-associated macrophages

Mitochondrial dysfunction in alveolar macrophages (AMs) drives chronic airway inflammation in chronic obstructive pulmonary disease (COPD). Adenylyl cyclase 7 (ADCY7) is a key enzyme in cAMP signaling, but its role in macrophage mitochondrial dysfunction and immune regulation in COPD remains unclear. Isoforskolin (ISOF), a bioactive natural product from Coleus forskohlii, has known anti-inflammatory properties, yet whether it improves macrophage mitochondrial function via ADCY7 is unknown.

To investigate whether ISOF acts through ADCY7 to restore mitochondrial function and correct the dysfunctional phenotype of a COPD-enriched ADCY7⁺CCL4⁺ macrophage subpopulation.

ADCY7 expression was measured in AMs from COPD patients. Single-cell and bulk transcriptomics (GSE171541, GSE57148) were used to identify ADCY7⁺ macrophage subpopulations. Network pharmacology, molecular docking and molecular dynamics simulations predicted the ISOF-ADCY7 interaction. A cigarette smoke extract (CSE)-induced THP-1-derived macrophage model and a cigarette smoke plus lipopolysaccharide (LPS)-induced mouse COPD model were employed, combined with ADCY7 silencing and rescue experiments. Mitochondrial function was assessed by Seahorse analysis, transmission electron microscopy, mtROS, mtDNA copy number, ATP, JC-1 and calcium assays.

ADCY7 expression was significantly downregulated in AMs from COPD patients and negatively correlated with lung function. Single-cell analysis identified a COPD-enriched ADCY7⁺CCL4⁺ macrophage subpopulation exhibiting a transitional inflammatory-repair phenotype. Molecular docking and dynamics simulations predicted stable binding of ISOF to ADCY7 (binding energy -5.9 kcal/mol). In vitro and in vivo experiments confirmed that ISOF upregulated ADCY7 expression. In vivo, ISOF improved pulmonary function, reduced collagen deposition and inflammatory cytokines (TNF-α, IL-1β, IL-6), and increased cAMP and ATP levels in mouse AMs. In vitro, ISOF reversed CSE-induced mitochondrial ultrastructural damage, calcium overload, mtROS overproduction, loss of mitochondrial membrane potential and respiratory chain deficiency.

ISOF alleviates COPD by modulating ADCY7-dependent pathways to improve macrophage mitochondrial function and reverse the functional imbalance of the ADCY7⁺CCL4⁺ macrophage subpopulation. These findings position ISOF as a promising immunometabolic and mitochondrial-targeted candidate for COPD therapy.