Multi-omics reveals cholesterol-driven macrophage metabolic reprogramming and inflammation in chronic obstructive pulmonary disease

Abstract

Background: Chronic obstructive pulmonary disease (COPD) is a progressive inflammatory disorder with rising global morbidity and mortality. Emerging evidence suggests that systemic metabolic alterations, particularly dyslipidemia, contribute to COPD pathogenesis. However, the mechanisms linking lipid dysregulation to pulmonary inflammation and tissue injury remain poorly defined.

Methods: Untargeted metabolomic profiling was performed on plasma samples from healthy individuals and patients with stage III-IV COPD to identify disease associated metabolic alterations. A high-cholesterol diet (HCD) mouse model, with or without chronic cigarette smoke exposure, was used to examine the impact of systemic cholesterol elevation on lung structure and inflammation. THP-1 derived and bone marrow derived macrophages were employed to assess cholesterol-induced mitochondrial dysfunction, ROS production, and downstream inflammatory signaling. Transcriptomic profiling was conducted to identify key molecular mediators.

Results: Plasma metabolomics revealed significant dysregulation of lipid pathways in COPD, with elevated cholesterol levels inversely correlated with lung function. In vivo, HCD feeding induced pulmonary inflammation and further exacerbated cigarette smoke induced alveolar destruction. In macrophages, combined cholesterol loading and cigarette smoke extraction treatment disrupted mitochondrial integrity, reduced respiratory capacity, and increased ROS production. Excess ROS upregulated PPIA, which activated NF-κB signaling and enhanced IL-1β secretion. Silencing PPIA or inhibiting ROS attenuated NF-κB activation and cytokine release. Consistent with these findings, lungs from HCD-fed, cigarette smoke exposed mice exhibited increased PPIA expression and NF-κB phosphorylation, and PPIA levels were elevated in bronchoalveolar lavage fluid from COPD patients.

Conclusions: This study identifies a cholesterol-driven metabolic–inflammatory pathway in which mitochondrial dysfunction and ROS-dependent activation of the PPIA–NF-κB axis in macrophages contribute to persistent pulmonary inflammation in COPD. These findings establish a mechanistic link between systemic cholesterol dysregulation and COPD progression and highlight cholesterol metabolism and mitochondrial homeostasis as potential therapeutic targets.

Supplementary Information: The online version contains supplementary material available at 10.1186/s13073-025-01591-w.

Keywords: Cholesterol metabolism; Chronic obstructive pulmonary disease; Metabolomics; Mitochondrial dysfunction; Peptidylprolyl isomerase A; Pulmonary inflammation; Reactive oxygen species.

Fig. 1

Plasma cholesterol levels are elevated and correlate with lung function decline in COPD. A Principal component analysis (PCA) showing distinct separation between plasma metabolomic profiles of healthy controls and COPD patients. B OPLS-DA score plot confirming distinct metabolic signatures between the two groups. C Volcano plot of differential metabolites identifying 199 upregulated and 188 downregulated compounds in COPD plasma. FC, fold change; VIP, variable importance in projection. D Pathway enrichment analysis revealing significant metabolic alterations. E Metabolite set enrichment analysis highlighting dysregulated metabolite clusters. F–G Correlation analysis showing inverse associations between plasma cholesterol levels and lung function parameters (FEV₁/FVC and FEV₁% predicted). H–I Quantification of plasma cholesterol levels showing progressive elevation with COPD severity in the discovery (H) and validation (I) cohorts

Fig. 2

High-cholesterol diet promotes alveolar destruction and lung inflammation in mice. A Schematic of the 6‑month experimental design comparing normal and HCD under air or CS exposure. B Comparison of body weight after 6 months under the indicated conditions. C Cholesterol levels in lung tissue following 6 months of diet and exposure. D Representative Oil Red O staining showing lipid distribution in lungs from each group. E Pulmonary function results, including functional residual capacity (FRC), chord compliance (Cchord), forced vital capacity (FVC), and the ratios of forced expiratory volume at 20 ms or 50 ms to FVC (FEV₂₀/FVC, FEV₅₀/FVC). F Representative lung histology and (G) quantification of the mean linear intercept (MLI). H Representative airway histology and (I) quantification of airway epithelial thickness. J Proportion of macrophages among total cells in bronchoalveolar lavage fluid. K–M Levels of IL‑1β, TNF‑α, and IL‑10 in lung tissue homogenates

Fig. 3

Cigarette smoke disrupts hepatic lipid metabolism and promotes cholesterol accumulation. A Oil Red O staining showing lipid accumulation in liver tissues from mice exposed to air or CS for 6 months. B–C Cholesterol levels in liver tissue after 4 and 6 months of CS exposure. D–E Western blot and densitometric analysis showing concentration-dependent reduction of HSD3B7 expression in hepatocytes following CSE treatment. F–G Western blot and quantification of HSD3B7 protein levels in liver tissues from air- and CS-exposed mice

Fig. 4

Cholesterol exacerbates CS induced mitochondrial dysfunction in macrophages. A Oil Red O staining showing lipid accumulation and increased alveolar macrophages in lung tissues of CS-HCD mice. B Transmission electron micrographs of THP-1 derived macrophages treated with CSE, cholesterol, or their combination, showing swollen mitochondria with disrupted cristae, especially in the CSE + Chol group. C–I Mitochondrial oxygen consumption rate (OCR) analysis, including the OCR trace (C), basal respiration (D), maximal respiration (E), spare respiratory capacity (F), non-mitochondrial respiration (G), proton leak (H), and ATP production (I)

Fig. 5

HCD elevates PPIA expression in lungs of CS exposed mice. A PCA plot showing distinct transcriptomic profiles between CS-Normal and CS-Chol mouse lungs. B Volcano plot of 146 differentially expressed genes (84 upregulated and 62 downregulated) in CS-Chol lungs. FC, fold change. C Protein–protein interaction (PPI) network identifying PPIA as a central hub gene among cholesterol-responsive proteins. The node size represents the degree (number of direct interactors) of each protein, indicating its relative importance within the network, while edge width reflects the strength of the interaction. D Ppia transcripts in mouse lungs as identified by RNA-Seq. E Validation of Ppia mRNA expression by qPCR. F-G Western blot and quantification showing increased PPIA protein levels in CS-Chol lungs

Fig. 6

Combined CSE and Cholesterol treatment induces ROS production, upregulates PPIA and activates NF-κB signaling in macrophages. A Single-cell RNA-Seq data from healthy human lungs showing predominant PPIA expression in alveolar macrophages and myofibroblasts. B-C Western blot and quantification of PPIA expression in THP-1–derived macrophages treated with CSE, cholesterol, or CSE + cholesterol. D-E ROS fluorescence assay and quantification showing elevated ROS production in THP-1–derived macrophages, especially in the CSE + Chol group. F-G Western blot showing PPIA expression after treatment with a ROS agonist (Rosup, F) or a ROS inhibitor (Mito-TEMPO, G) in bone-marrow-derived macrophages (BMDMs). H-I Quantification of PPIA protein levels from (F) and (G). J-K Western blot and quantification showing increased p65 phosphorylation following CSE + Chol treatment, which was attenuated by Ppia knockdown. L-M IL-1β secretion in culture media from THP-1 derived macrophages and BMDMs treated with CSE + Chol, showing significant reduction upon Ppia silencing. N–O Elevated phospho-p65 levels in lung tissues of CS-Chol mice compared with CS-Normal controls. P Increased PPIA levels in BALF from COPD patients