Project description:We conducted a prospective cohort study with independent Discovery and Validation cohorts, to formulate predictive biomarkers for Bronchopulmonary Dysplasia in extremely preterm infants. Tracheal aspirate samples were collected at birth from extremely preterm infants. Exosomes were extracted from tracheal aspirates and total RNA was extracted from these exosomes from individual samples. miRNA profiling for all ~ 800 miRNAs was conducted on each sample by nanostring platform. This study found that a distinct airway exosomal miRNA sigrature at birth (decreased miR 876-3p) predicts future development of severe Bronchopulmonary Dysplasia in extremely preterm infants.
Project description:Background: Metabolic dysregulation has been implicated in bronchopulmonary dysplasia development. Taurine is an essential amino acid for neonates and is critically involved in glucose and fatty acid metabolism. Neonatal tissue obtains taurine mainly through the taurine transporter. The biological role of taurine in neonatal lung development has never been explored. As glucose metabolism mechanistically modulates angiogenesis and angiogenesis is the central player for neonatal lung development, we hypothesize that taurine depletion contributes to bronchopulmonary dysplasia development. Results: Although most genes and proteins for oxidative phosphorylation were enriched in hyperoxia pup lungs, the complex-1 activity decreased. The decrease in taurine-dependent complex-1 core subunits, ND5 and ND6, in hyperoxia lungs reasonably explained the discrepancy. Metabolomics analysis demonstrated decreased lung taurine with increased blood taurine of hyperoxia pups, compatible with the decreased taurine transporter expression. Decreased glycosylation and increased degradation explained the decreased taurine transporter expression. The results of the complementary study using tunicamycin and tauroursodeoxycholic acid studies supported that endoplasmic reticulum stress contributes to decreased taurine transporter expression in hyperoxia lungs. The effect of taurine treatment on reducing endoplasmic reticulum stress, increasing ND5 and ND6 expression, angiogenesis, and, most importantly, the alveolar formation is beneficial to hyperoxia rat pups. Conclusion: Hyperoxia exposure causes endoplasmic reticulum stress, increases taurine transporter degradation, and leads to taurine depletion in the neonatal lungs with subsequent metabolic dysregulation, resulting in poor alveolar formation of the neonatal lungs. We provide evidence of the never-being-reported protective role of taurine in neonatal lung development. The fact that taurine attenuates the severity of bronchopulmonary dysplasia by reducing hyperoxia-induced endoplasmic reticulum stress and mitochondrial dysfunction indicates its therapeutic potential for treating bronchopulmonary dysplasia.
Project description:We performed miRNA and mRNA profiling at postnatal day 14 and day 29 to compare hyperoxia-induced bronchopulmonary dysplasia and wild type. We built potential miRNA-mRNA interaction networks specific to brochopulmonary dysplasia. Replicated time course of mouse lung development at 2 time points (P14, P29). Three replicates per time point for bronchopulmonary dysplasia induced by hyperoxia mouse lung, and two replicates per time point for wild type mouse lung. This dataset represents the mRNA expression profiling component of the study.
Project description:We performed miRNA and mRNA profiling at postnatal day 14 and day 29 to compare hyperoxia-induced bronchopulmonary dysplasia and wild type. We built potential miRNA-mRNA interaction networks specific to brochopulmonary dysplasia. Replicated time course of mouse lung development at 2 time points (P14, P29). Three replicates per time point for bronchopulmonary dysplasia induced by hyperoxia mouse lung, and two replicates per time point for wild type mouse lung. This dataset represents the miRNA profiling component of the study.
Project description:Oxygen is toxic across all three domains of life. Yet, the underlying molecular mechanisms remain largely unknown. Here, we systematically investigate the major cellular pathways affected by excess molecular oxygen. We find that hyperoxia destabilizes a specific subset of Fe-S cluster (ISC)-containing proteins, resulting in impaired diphthamide synthesis, purine metabolism, nucleotide excision repair, and electron transport chain (ETC) function. Our findings translate to primary human lung cells and a mouse model of pulmonary oxygen toxicity. We demonstrate that the ETC is the most vulnerable to damage, resulting in decreased mitochondrial oxygen consumption. This leads to further tissue hyperoxia and cyclic damage of the additional ISC-containing pathways. In support of this model, primary ETC dysfunction in the Ndufs4 KO mouse model causes lung tissue hyperoxia and dramatically increases sensitivity to hyperoxia-mediated ISC damage. This work has important implications for hyperoxia pathologies, including bronchopulmonary dysplasia, ischemia-reperfusion injury, aging, and mitochondrial disorders.
Project description:To study whether increase in mitochondrial oxidative stress (SOD2 removal) and decrease in mitochondrial DNA repair (Ogg1 dMTS) results into increase in mitochondrial DNA mutation load. Oxidative stress has been suggested to induce mutations in mtDNA. To verify this, we extracted and sequenced (Illumina) mitochondrial DNA from heart Sod2 knockout animals that were also deficient for mitochondrial base-excision repair. The repair deficiency was induced by removing the genomic region encoding for the predicted mitochondrial targeting sequence from endogenous OGG1 (L2 to W23) called Ogg1 dMTS mice, thus excluding the protein from mitochondria. OGG1 is a DNA glycosylase that recognizes and repairs 8-oxo-dG damage from DNA. Oxidative stress can induce 8-oxo-dG lesions, thus we removed the mitochondrial matrix localized superoxide dismutase (SOD2) from these mice to increase the level of oxidative stress. 8-oxo-dG lesion can be mutagenic because some DNA repair polymerases are known to erroneously incorporate adenosine opposite to 8-oxo-dG during replication leading to GC>TA transversion mutations.