a-minimally-invasive-method-for-intratracheal-instillation-drugs

A Minimally Invasive Method for Intratracheal Instillation of Drugs in Neonatal Rodents to Treat Lung Disease

Treatment of neonatal rodent with drugs instilled directly into the trachea could serve as a valuable tool to study the impact of a locally administered ...

Case Western Reserve University

Hyperoxia (HO)-induced lung injury contributes to bronchopulmonary dysplasia (BPD) in preterm newborns. Intractable wheezing seen in BPD survivors is associated with airway remodeling (AWRM). Sphingosine kinase 1 (SPHK1)/sphingosine-1-phosphate (S1P) signaling promotes HO-mediated neonatal BPD; however, its role in the sequela of AWRM is not known. We noted an increased concentration of S1P in tracheal aspirates of neonatal infants with severe BPD, and earlier, demonstrated that  mice showed protection against HO-induced BPD. The role of SPHK1/S1P in promoting AWRM following exposure of neonates to HO was investigated in a murine model. Therapy using PF543, the specific SPHK1 inhibitor, during neonatal HO reduced alveolar simplification followed by reduced AWRM in adult mice. This was associated with reduced airway hyperreactivity to intravenous methacholine. Neonatal HO exposure was associated with increased expression of SPHK1 in lung tissue of adult mice, which was reduced with PF543 therapy in the neonatal stage. This was accompanied by amelioration of HO-induced reduction of E-cadherin in airway epithelium. This may be suggestive of arrested partial epithelial mesenchymal transition (EMT) induced by HO. In vitro studies using human primary airway epithelial cells (HAEpCs) showed that SPHK1 inhibition or deletion restored HO-induced reduction in E-cadherin and reduced formation of mitochondrial reactive oxygen species (mtROS). Blocking mtROS with MitoTempo attenuated HO-induced partial EMT of HAEpCs. These results collectively support a therapeutic role for PF543 in preventing HO-induced BPD in neonates and the long-term sequela of AWRM, thus conferring a long-term protection resulting in improved lung development and function.

Neonatal therapy with PF543, a sphingosine kinase 1 inhibitor, ameliorates hyperoxia-induced airway remodeling in a murine model of bronchopulmonary dysplasia.

 () infection increases reactive oxygen species (ROS), and earlier, we have shown a role for NADPH oxidase-derived ROS in -mediated lung inflammation and injury. Here, we show a role for the lung epithelial cell (LEpC) NOX4 in -mediated chromatin remodeling and lung inflammation. Intratracheal administration of  to Nox4 mice for 24 h caused lung inflammatory injury; however, epithelial cell-deleted Nox4 mice exhibited reduced lung inflammatory injury, oxidative stress, secretion of pro-inflammatory cytokines, and decreased histone acetylation. In LEpCs, NOX4 was localized both in the cytoplasmic and nuclear fractions, and  stimulation increased the nuclear NOX4 expression and ROS production. Downregulation or inhibition of NOX4 and PKC δ attenuated the -induced nuclear ROS. -induced histone acetylation was attenuated by -specific siRNA, unlike .  stimulation increased HDAC1/2 oxidation and reduced HDAC1/2 activity. The -induced oxidation of HDAC2 was attenuated by -acetyl-L-cysteine and siRNA specific for , , and .  stimulated RAC1 activation in the nucleus and enhanced the association between HDAC2 and RAC1, p-PKC δ, and NOX4 in LEpCs. Our results revealed a critical role for the alveolar epithelial NOX4 in mediating -induced lung inflammatory injury via nuclear ROS generation, HDAC1/2 oxidation, and chromatin remodeling.

NOX4 Mediates -Induced Nuclear Reactive Oxygen Species Generation and Chromatin Remodeling in Lung Epithelium.

Neonatal lung injury as a consequence of hyperoxia (HO) therapy and ventilator care contribute to the development of bronchopulmonary dysplasia (BPD). Increased expression and activity of lysyl oxidase (LOX), a key enzyme that cross-links collagen, was associated with increased sphingosine kinase 1 (SPHK1) in human BPD. We, therefore, examined closely the link between LOX and SPHK1 in BPD.

Sphingosine kinase 1 regulates lysyl oxidase through STAT3 in hyperoxia-mediated neonatal lung injury.

We have earlier shown that hyperoxia (HO)-induced sphingosine kinase 1 (SPHK1)/sphingosine-1-phosphate (S1P) signaling contribute to bronchopulmonary dysplasia (BPD). S1P acts through G protein-coupled receptors, S1P through S1P. Further, we noted that heterozygous deletion of S1pr1 ameliorated the HO-induced BPD in the murine model. The mechanism by which S1P signaling contributes to HO-induced BPD was explored.

Article	Year
Neonatal therapy with PF543, a sphingosine kinase 1 inhibitor, ameliorates hyperoxia-induced airway remodeling in a murine model of bronchopulmonary dysplasia. American journal of physiology. Lung cellular and molecular physiology\| PubMed ID: 32697651	2020
NOX4 Mediates -Induced Nuclear Reactive Oxygen Species Generation and Chromatin Remodeling in Lung Epithelium. Antioxidants (Basel, Switzerland)\| PubMed ID: 33802941	2021
Sphingosine kinase 1 regulates lysyl oxidase through STAT3 in hyperoxia-mediated neonatal lung injury. Thorax\| PubMed ID: 33883249	2021
Hyperoxia-induced S1P signaling reduced angiogenesis by suppression of TIE-2 leading to experimental bronchopulmonary dysplasia. Cell biochemistry and biophysics\| PubMed ID: 34176100	2021

Tara Sudhadevi

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