TREM2 Orchestrates Myeloid Cell Programming and Immune Dysregulation in Pulmonary Hypertension

Authors

Oliveira, A. C., da Silva, F., Zhang, Y., Alves, M. D., Pham, A. T., Harris, C. L., Khanfar, S., Abdelnor, R., Alvarez-Castanon, J. V., Philips, C. M., Tarantino, M., Fu, C., Virk, S. T., Ray, K. E., Chen, L., Krause, E. G., de Kloet, A. D., Bryant, A. J.

Abstract

Pulmonary hypertension (PH) is a progressive and fatal disease characterized by pulmonary vascular remodeling, inflammation, and immune dysregulation. Myeloid-derived suppressor cells (MDSCs) and macrophages contribute to PAH pathobiology; however, the molecular regulators of their pathological activation remain poorly defined. The triggering receptor expressed on myeloid cells 2 (TREM2) is an immunomodulatory receptor that shapes myeloid cell metabolism, survival, and immunosuppressive function, yet its role in PH has not been investigated. Methods: Single-cell RNA sequencing (scRNA-seq) data from human pulmonary artery tissue (GSE210248; n=3 PAH, n=3 donors) were analyzed to characterize TREM2 expression across cell populations. Wild-type (WT) and global TREM2 knockout (TREM2 KO) mice were exposed to chronic hypoxia (10% FiO2, 28 days). Hemodynamic, histological, flow cytometric, and ex vivo functional assessments were performed. TREM2 expression was measured by flow cytometry in circulating MDSCs from PAH patients (n=22) and healthy controls (n=13). Results: TREM2 was markedly enriched in monocyte/macrophage populations in PH pulmonary arteries and TREM2-high immune cells exhibited transcriptional downregulation of chemotaxis programs and upregulation of antigen processing and MHC II presentation pathways. TREM2 deficiency significantly attenuated hypoxia-induced RVSP increase, right ventricular dysfunction, pulmonary inflammation, and vascular remodeling. MDSCs from TREM2 KO mice exerted significantly less suppression of CD4+ and CD8+ T cell proliferation. TREM2 was significantly elevated in circulating MDSCs from PAH patients and showed a directional association with hemodynamic severity. Conclusions: TREM2 is a novel regulator of myeloid-driven immunosuppression and vascular remodeling in PAH and warrants investigation as a therapeutic target and biomarker.

Preprint server: bioRxiv
The authors list and abstract were imported from bioRxiv on 25 Sep 2026.

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