Project description:Bronchopulmonary dysplasia (BPD) is characterized by an arrest in alveolarization, abnormal vascular development and variable interstitial fibroproliferation in the premature lung. Endothelial to mesenchymal transition (Endo-MT) may be a source of pathologic fibrosis in many organ systems. Whether Endo-MT contributes to the pathogenesis of BPD is not known. We tested the hypothesis that pulmonary endothelial cells will show increased expression of Endo-MT markers upon exposure to hyperoxia and that sex as a biological variable will modulate differences in expression. WT and Cdh5-PAC CreERT2 (endothelial reporter) neonatal male and female mice (C57BL6) were exposed to hyperoxia (0.95 FiO2) either during the saccular stage of lung development (95% FiO2; PND1-5) or through the saccular and early alveolar stages of lung development (75% FiO2; PND1-14). Expression of Endo-MT markers were measured in whole lung and endothelial cell mRNA. Sorted lung endothelial cells were subjected to bulk RNA-Seq. We show that exposure of the neonatal lung to hyperoxia leads to upregulation of key markers of EndoMT Neonatal male mice show higher expression of genes related to EndoMT. Furthermore, using lung sc-RNAseq data from neonatal lung we were able to show that xxx. Markers related to Endo-MT are upregulated in the neonatal lung upon exposure to hyperoxia and show sex-specific differences. Mechanisms mediating EndoMT in the injured neonatal lung can modulate the response of the neonatal lung to hyperoxic injury and need further investigation.
Project description:Recovery from lung injury during the neonatal period requires the orchestration of many biological pathways. Modulation of biological pathways can drive the developing lung towards proper repair or persistent maldevelopment after injury that can lead to a disease phenotype. Sex as a biological variable can modulate these pathways differently in the male and female lung exposed to neonatal hyperoxia. In this study, we assessed the contribution of cellular diversity in the male and female neonatal lung following injury. Our objective was to investigate sex and cell-type specific transcriptional changes that drive repair or persistent injury in the neonatal lung at single-cell resolution and delineate the alterations in the immune-endothelial cell communication networks in the developing lung using single cell RNA sequencing (sc-RNAseq) in a murine model of hyperoxic lung injury. We generated transcriptional profiles of >55,000 cells isolated from the lungs of postnatal day 1 (PND 1) andpostnatal day 21 (PND 21) neonatal male and female C57BL/6 mice exposed to 95% FiO2between PND 1-5 (saccular stage of lung development).We show the presence of sex-based differences in the transcriptional states of lung endothelial and immune cells at PND 1 and PND 21. Furthermore, we demonstrate that biological sex significantly influences the response to injury, with a greater number of differentially expressed genes showing sex-specific patterns than those shared between male and female lungs. Pseudotime trajectory analysis highlighted genes needed for lung development that were altered by hyperoxia. Finally, we show intercellular communication between endothelial and immune cells at saccular and alveolar stages of lung development with sex-based biases in the cross-talk and identify novel ligand-receptor pairs. Our findings provide valuable insights into the cell diversity, transcriptional state, developmental trajectory, and cell-cell communication underlying neonatal lung injury, with implications for understanding lung development and therapeutic interventions while highlighting the crucial role of sex as a biological variable.
Project description:The goal of the project was to delineate sex-specific differences in the neonatal lung exposed to postnatal hyperoxia to model the pathophysiologic mechanisms in the human disease; bronchopulmonary dysplasia (BPD).
Project description:Resident-tissue macrophages (RTMs) arise from embryonic precursors1,2, yet the developmental signals that shape their longevity remain largely unknown. Here we demonstrate in mice genetically deficient in 12-lipoxygenase and 15-lipoxygenase (Alox15-/- mice) that neonatal neutrophil-derived 12-HETE is required for self-renewal and maintenance of alveolar macrophages (AMs) during lung development. Although the seeding and differentiation of AM progenitors remained intact, the absence of 12-HETE led to a significant reduction in AMs in adult lungs and enhanced senescence owing to increased prostaglandin E2 production. A compromised AM compartment resulted in increased susceptibility to acute lung injury induced by lipopolysaccharide and to pulmonary infections with influenza A virus or SARS-CoV-2. Our results highlight the complexity of prenatal RTM programming and reveal their dependency on in trans eicosanoid production by neutrophils for lifelong self-renewal.
Project description:Immaturity of alveolar macrophages (AMs) around birth contributes to the susceptibility of newborns to lung disease. However, the molecular features differentiating neonatal and mature, adult AMs are poorly understood. In this study, we identify the unique transcriptomes and enhancer landscapes of neonatal and adult AMs in mice. Although the core AM signature was similar, murine adult AMs expressed higher levels of genes involved in lipid metabolism, whereas neonatal AMs expressed a largely proinflammatory gene profile. Open enhancer regions identified by an assay for transposase-accessible chromatin followed by high-throughput sequencing (ATAC-seq) contained motifs for nuclear receptors, MITF, and STAT in adult AMs and AP-1 and NF-κB in neonatal AMs. Intranasal LPS activated a similar innate immune response in both neonatal and adult mice, with higher basal expression of inflammatory genes in neonates. The lung microenvironment drove many of the distinguishing gene expression and open chromatin characteristics of neonatal and adult AMs. Neonatal mouse AMs retained high expression of some proinflammatory genes, suggesting that the differences in neonatal AMs result from both inherent cell properties and environmental influences.
Project description:BackgroundThe pathophysiology and mechanisms of irritable bowel syndrome (IBS) involve both central and peripheral mechanisms that result in altered perception, as well as changes in bowel functions. These dysfunctions are associated with motor, sensory, immune, barrier, and intraluminal perturbations, including the microbiota, and their products and endogenous molecules with bioactive properties. There is evidence that these mechanisms are altered in both females and males. However, there is also increasing evidence that sex is a biological variable that impacts a number of aspects of the mechanisms, epidemiology, and manifestations of IBS.PurposeThe objective of this article is to review the evidence of the differences among genders of the following factors in IBS: the brain-gut axis and sex hormones, epidemiology, diagnostic criteria and prognosis, pain perception, colonic transit, abdominal distension, overlap with urogynecological conditions, psychologic issues, anorexia, fibromyalgia, serotonin, and responsiveness to treatment of IBS. It is important to consider the variations attributable to sex in order to enhance the management of patients with IBS and the research of mechanisms involved in IBS.