Acute respiratory distress syndrome (ARDS) remains a frequently fatal syndrome with incompletely defined mechanisms. The authors aimed to identify genes that contribute to ARDS pathogenesis through effects on macrophage polarization, focusing on genes that associate with ARDS in bulk transcriptomic datasets and that are differentially expressed between M1 macrophages and M2 macrophages in single-cell data. The stated goal was to generate candidate genes for functional follow-up and to validate top candidates in vitro and in vivo.
The study combined multiple public transcriptomic resources. Bulk RNA profiling from three independent murine ARDS models was analyzed to find commonly differentially expressed genes. Single-cell RNA sequencing data derived from ARDS lungs were used to identify genes that differ between M1 and M2 macrophage populations. The authors explicitly report that all transcriptomic and single-cell data analyzed were obtained from public GEO repositories and list the accession numbers: GSE193958, GSE216943, GSE263867, and GSE217324.
Candidate genes were defined by intersecting the list of genes commonly altered across the three bulk murine ARDS datasets with genes differentially expressed between M1 and M2 macrophages in the single-cell dataset. From this intersection, the investigators selected top candidates for validation. Validation was performed by qRT-PCR in the lungs of ARDS mice. The gene highlighted as the top candidate is TARM1, which the authors report was markedly elevated in ARDS lung tissue and shown to colocalize with the macrophage marker CD68 in lung tissue.
To explore mechanism, the authors examined the effects of manipulating TARM1 in a macrophage cell line. In LPS-stimulated RAW264.7 macrophages, knockdown of TARM1 reduced expression of pro‑inflammatory cytokines and attenuated LPS-induced M1 macrophage polarization. These in vitro data are presented as functional evidence that TARM1 can regulate macrophage activation states and downstream proinflammatory signaling in a commonly used macrophage model.
The study extended the findings to in vivo ARDS models by using macrophage-specific AAV6-mediated knockdown of TARM1. Macrophage-targeted suppression of TARM1 in the animal models led to reductions in several experimental markers of lung injury. Specifically, the authors report that macrophage-specific TARM1 suppression decreased the lung wet-to-dry ratio, lowered inflammatory cytokine levels measured in the lung, and ameliorated histologic lung damage. These outcomes are described as indicating that TARM1 contributes to ARDS pathogenesis in vivo, at least in the experimental systems used.
Taken together, the bioinformatic intersection strategy and subsequent experimental validation support a model in which TARM1 promotes ARDS progression by regulating macrophage M1 polarization and associated proinflammatory cytokine production. The reported mitigation of lung injury after macrophage-specific TARM1 knockdown suggests that TARM1 could be explored as a potential therapeutic target in ARDS.
Limitations noted by inference from the source: the analyses and experiments were conducted in murine ARDS models and in the RAW264.7 macrophage cell line; thus, translational relevance to human ARDS requires further study. The abstract and PubMed entry provide the study design, datasets used, and qualitative outcomes, but do not report detailed numerical effect sizes, specific cytokine names and concentrations, sample sizes, or full methodological parameters in the abstract. Those details were not reported in the source summary and would require consultation of the full text for complete appraisal.
The authors declare no competing financial interests or personal relationships that could have influenced the reported work. All transcriptomic and single-cell datasets used for discovery were obtained from public GEO repositories (GSE193958, GSE216943, GSE263867, and GSE217324). Experimental validation included qRT-PCR on ARDS mouse lungs, LPS-stimulated RAW264.7 macrophage assays, and macrophage-specific AAV6-mediated knockdown in vivo. The study was reported in Biochemical and Biophysical Research Communications (doi: 10.1016/j.bbrc.2026.154466).