Molecular imaging of chemokine-like receptor 1 (CMKLR1) in experimental acute lung injury.

The lack of techniques for noninvasive imaging of inflammation has challenged precision medicine management of acute respiratory distress syndrome (ARDS). Here, we determined the potential of positron emission tomography (PET) of chemokine-like receptor-1 (CMKLR1) to monitor lung inflammation in a murine model of lipopolysaccharide-induced injury. Lung uptake of a CMKLR1-targeting radiotracer, [64Cu]NODAGA-CG34, was significantly increased in lipopolysaccharide-induced injury, correlated with the expression of multiple inflammatory markers, and reduced by dexamethasone treatment. Monocyte-derived macrophages, followed by interstitial macrophages and monocytes were the major CMKLR1-expressing leukocytes contributing to the increased tracer uptake throughout the first week of lipopolysaccharide-induced injury. The clinical relevance of CMKLR1 as a biomarker of lung inflammation in ARDS was confirmed using single-nuclei RNA-sequencing datasets which showed significant increases in CMKLR1 expression among transcriptionally distinct subsets of lung monocytes and macrophages in COVID-19 patients vs. controls. CMKLR1-targeted PET is a promising strategy to monitor the dynamics of lung inflammation and response to anti-inflammatory treatment in ARDS.

microRNA-144 functions as a diagnostic and prognostic marker for retinoblastoma.

OBJECTIVES: Retinoblastoma (RB) is a highly malignant eye tumor with a low survival rate and a high metastatic rate. The current work was designed to investigate the potential roles of microRNA-144 (miR-144) in the diagnosis and prognosis of RB. METHODS: miR-144 expression levels in RB tissues and adjacent normal tissues, as well as serum samples from RB patients and healthy controls were measured. The association between miR-144 expression levels and clinical features were analyzed. Moreover, diagnostic and prognostic values of miR-144 in RB were verified by receiver operating characteristic analysis and Kaplan-Meier survival assays. RESULTS: The expression level of miR-144 was markedly decreased in tumor tissues of RB patients, and the expression level of miR-144 was positively associated with tumor size and metastasis in RB patients. Moreover, miR-144 can distinguish tumor tissues from normal tissues with high specificity and sensitivity, and RB patients with lower miR-144 expression have shorter overall and disease-free survival rates than those with higher miR-144 expression. Alternatively, miR-144 also decreased in the serum of RB patients in comparison with healthy subjects, and miR-144 expression levels in the tissue samples and serum were positively correlated. Furthermore, miR-144 levels in the serum of RB patients sensitively distinguished RB patients from healthy controls. CONCLUSIONS: miR-144 expression was downregulated in serum and tissue samples of RB patients and may function as a diagnostic and prognostic marker for RB.

Developmental trajectory of prehematopoietic stem cell formation from endothelium.

Hematopoietic stem and progenitor cells (HSPCs) in the bone marrow are derived from a small population of hemogenic endothelial (HE) cells located in the major arteries of the mammalian embryo. HE cells undergo an endothelial to hematopoietic cell transition, giving rise to HSPCs that accumulate in intra-arterial clusters (IAC) before colonizing the fetal liver. To examine the cell and molecular transitions between endothelial (E), HE, and IAC cells, and the heterogeneity of HSPCs within IACs, we profiled ∼40 000 cells from the caudal arteries (dorsal aorta, umbilical, vitelline) of 9.5 days post coitus (dpc) to 11.5 dpc mouse embryos by single-cell RNA sequencing and single-cell assay for transposase-accessible chromatin sequencing. We identified a continuous developmental trajectory from E to HE to IAC cells, with identifiable intermediate stages. The intermediate stage most proximal to HE, which we term pre-HE, is characterized by increased accessibility of chromatin enriched for SOX, FOX, GATA, and SMAD motifs. A developmental bottleneck separates pre-HE from HE, with RUNX1 dosage regulating the efficiency of the pre-HE to HE transition. A distal candidate Runx1 enhancer exhibits high chromatin accessibility specifically in pre-HE cells at the bottleneck, but loses accessibility thereafter. Distinct developmental trajectories within IAC cells result in 2 populations of CD45+ HSPCs; an initial wave of lymphomyeloid-biased progenitors, followed by precursors of hematopoietic stem cells (pre-HSCs). This multiomics single-cell atlas significantly expands our understanding of pre-HSC ontogeny.

Runx1 negatively regulates inflammatory cytokine production by neutrophils in response to Toll-like receptor signaling.

RUNX1 is frequently mutated in myeloid and lymphoid malignancies. It has been shown to negatively regulate Toll-like receptor 4 (TLR4) signaling through nuclear factor κB (NF-κB) in lung epithelial cells. Here we show that RUNX1 regulates TLR1/2 and TLR4 signaling and inflammatory cytokine production by neutrophils. Hematopoietic-specific RUNX1 loss increased the production of proinflammatory mediators, including tumor necrosis factor-α (TNF-α), by bone marrow neutrophils in response to TLR1/2 and TLR4 agonists. Hematopoietic RUNX1 loss also resulted in profound damage to the lung parenchyma following inhalation of the TLR4 ligand lipopolysaccharide (LPS). However, neutrophils with neutrophil-specific RUNX1 loss lacked the inflammatory phenotype caused by pan-hematopoietic RUNX1 loss, indicating that dysregulated TLR4 signaling is not due to loss of RUNX1 in neutrophils per se. Rather, single-cell RNA sequencing indicates the dysregulation originates in a neutrophil precursor. Enhanced inflammatory cytokine production by neutrophils following pan-hematopoietic RUNX1 loss correlated with increased degradation of the inhibitor of NF-κB signaling, and RUNX1-deficient neutrophils displayed broad transcriptional upregulation of many of the core components of the TLR4 signaling pathway. Hence, early, pan-hematopoietic RUNX1 loss de-represses an innate immune signaling transcriptional program that is maintained in terminally differentiated neutrophils, resulting in their hyperinflammatory state. We hypothesize that inflammatory cytokine production by neutrophils may contribute to leukemia associated with inherited RUNX1 mutations.

microRNA-144 functions as a diagnostic and prognostic marker for retinoblastoma

OBJECTIVES: Retinoblastoma (RB) is a highly malignant eye tumor with a low survival rate and a high metastatic rate. The current work was designed to investigate the potential roles of microRNA-144 (miR-144) in the diagnosis and prognosis of RB. METHODS: miR-144 expression levels in RB tissues and adjacent normal tissues, as well as serum samples from RB patients and healthy controls were measured. The association between miR-144 expression levels and clinical features were analyzed. Moreover, diagnostic and prognostic values of miR-144 in RB were verified by receiver operating characteristic analysis and Kaplan-Meier survival assays. RESULTS: The expression level of miR-144 was markedly decreased in tumor tissues of RB patients, and the expression level of miR-144 was positively associated with tumor size and metastasis in RB patients. Moreover, miR-144 can distinguish tumor tissues from normal tissues with high specificity and sensitivity, and RB patients with lower miR-144 expression have shorter overall and disease-free survival rates than those with higher miR-144 expression. Alternatively, miR-144 also decreased in the serum of RB patients in comparison with healthy subjects, and miR-144 expression levels in the tissue samples and serum were positively correlated. Furthermore, miR-144 levels in the serum of RB patients sensitively distinguished RB patients from healthy controls. CONCLUSIONS: miR-144 expression was downregulated in serum and tissue samples of RB patients and may function as a diagnostic and prognostic marker for RB.