Fibroblast-derived CSF2 acts as a central paracrine effector linking metabolic stress to pro-inflammatory myeloid dysfunction and maladaptive pulmonary vascular remodeling in a murine PH-cHFpEF model.
Fibroblast-derived CSF2 links metabolic stress to pro-inflammatory myeloid dysfunction and pulmonary vascular remodeling in a preclinical model of HFpEF-associated pulmonary hypertension.
Abstract Introduction Pulmonary hypertension (PH) is a common and prognostically adverse complication in obese patients with heart failure with preserved ejection fraction (HFpEF). Cardiometabolic HFpEF–associated PH (PH-cHFpEF) is characterized by inflammation and metabolic dysregulation. Alterations in pulmonary immune cell populations, particularly interstitial and infiltrating macrophages, may amplify inflammation, and promote maladaptive vascular remodeling. However, the contribution of monocyte heterogeneity and macrophage activation to PH-cHFpEF pathogenesis remains unclear. Purpose To determine the role of monocytes and macrophages in driving vascular remodeling and inflammation in PH-cHFpEF. Methods A murine model of PH-cHFpEF was generated using high-fat diet and L-NAME treatment for 15 weeks. Right ventricular function and pulmonary pressures were assessed by echocardiography, hemodynamics, and treadmill exercise testing. Single-nucleus RNA sequencing (snRNA-seq) was performed to characterize pulmonary immune cell populations. Primary lung fibroblasts (mFb) were isolated and their secretome analyzed by proteomics. Mechanistic in vitro studies were conducted in THP-1 monocytes exposed to palmitic acid (PA) to model metabolic stress. Results PH-cHFpEF mice developed right ventricular dysfunction and elevated pulmonary pressures. SnRNA-seq revealed a marked expansion and transcriptional reprogramming of immune cells. Specifically, patrolling monocytes (pMos) exhibited Srgn and Dusp1 upregulation as well as Dram1 downregulation, consistent with enhanced granule-mediated secretion, activation of MAPK signaling, and impaired autophagy. On the other hand, CD206+MHC-II+ macrophages showed increased Atf3 and reduced Fkbp5 levels, suggesting activation of stress-resolution programs, heightened glucocorticoid sensitivity, and enhanced antigen-presenting/tissue-repair functions. In vitro, THP-1 macrophages exposed to PA showed a mixed but predominantly pro-inflammatory phenotype. Interactome analyses revealed that mFbs are the primary source of intercellular signals in HFpEF-PH lungs. Exposure of THP-1 cells to HFpEF-PH-mFb-conditioned media recapitulated macrophages activation, supporting a paracrine effect of mFbs. Proteomic profiling of mFb-conditioned media showed increased CSF2 secretion, a cytokine that promotes pro-inflammatory myeloid differentiation, activates MAPK cascade, augments Srgn-dependent granule biogenesis, and represses autophagy programs. Conclusion Our findings identify mFb-derived CSF2 as a central paracrine effector linking metabolic stress to myeloid dysfunction in PH-cHFpEF. CSF2-driven transcriptional program induces a pro-inflammatory activation state, suppresses autophagic programs, and alters tissue repair responses, collectively promoting maladaptive pulmonary vascular remodeling. Therefore, modulating the interaction between fibroblasts and immune cells may represent a new therapeutic avenue in PH-cHFpEF.Figure 1For image description, please refer to the figure legend and surrounding text. Figure 2For image description, please refer to the figure legend and surrounding text.
Masciovecchio et al. (Fri,) conducted a other in Cardiometabolic HFpEF-associated PH (PH-cHFpEF). High-fat diet and L-NAME was evaluated on Right ventricular function and pulmonary pressures. Fibroblast-derived CSF2 acts as a central paracrine effector linking metabolic stress to pro-inflammatory myeloid dysfunction and maladaptive pulmonary vascular remodeling in a murine PH-cHFpEF model.