Role of the LRP1-pPyk2-MMP9 pathway in hyperoxia-induced lung injury in neonatal rats. / LRP1-pPyk2-MMP9é€šè·¯åœ¨é«˜æ°§è¯±å¯¼æ–°ç”Ÿå¤§é¼ è‚ºæŸä¼¤ä¸­çš„ä½œç”¨.

OBJECTIVES: To study the role of the low-density lipoprotein receptor-related protein 1 (LRP1)-proline-rich tyrosine kinase 2 phosphorylation (pPyk2)-matrix metalloproteinases 9 (MMP9) pathway in hyperoxia-induced lung injury in neonatal rats. METHODS: A total of 16 neonatal rats were randomly placed in chambers containing room air (air group) or 95% medical oxygen (hyperoxia group) immediately after birth, with 8 rats in each group. All of the rats were sacrificed on day 8 of life. Hematoxylin and eosin staining was used to observe the pathological changes of lung tissue. ELISA was used to measure the levels of soluble LRP1 (sLRP1) and MMP9 in serum and bronchoalveolar lavage fluid (BALF). Western blot was used to measure the protein expression levels of LRP1, MMP9, Pyk2, and pPyk2 in lung tissue. RT-PCR was used to measure the mRNA expression levels of LRP1 and MMP9 in lung tissue. RESULTS: The hyperoxia group had significantly higher levels of sLRP1 and MMP9 in serum and BALF than the air group (P<0.05). Compared with the air group, the hyperoxia group had significant increases in the protein expression levels of LRP1, MMP9, and pPyk2 in lung tissue (P<0.05). The hyperoxia group had significantly higher relative mRNA expression levels of LRP1 and MMP9 in lung tissue than the air group (P<0.05). CONCLUSIONS: The activation of the LRP1-pPyk2-MMP9 pathway is enhanced in hyperoxia-induced lung injury in neonatal rats, which may be involved in the pathogenesis of bronchopulmonary dysplasia.

All-trans retinoic acid upregulates the expression of ciliary neurotrophic factor in retinal pigment epithelial cells.

Retinopathy of prematurity, a leading cause of visual impairment in low birth-weight infants, remains a crucial therapeutic challenge. Ciliary neurotrophic factor (CNTF) is a promyelinating trophic factor that promotes rod and cone photoreceptor survival and cone outer segment regeneration in the degenerating retina. Ciliary neurotrophic factor expression is regulated by many factors such as all-trans retinoic acid (ATRA). In this study, we found that ATRA increased CNTF expression in mouse retinal pigment epithelial (RPE) cells in a dose- and time-dependent manner, and PKA signaling pathway is necessary for ATRA-induced CNTF upregulation. Furthermore, we showed that ATRA promoted CNTF expression through CREB binding to its promoter region. In addition, CNTF levels were decreased in serum of retinopathy of prematurity children and in retinal tissue of oxygen-induced retinopathy mice. In mouse RPE cells cultured with high oxygen, CNTF expression and secretion were decreased, but could be recovered after treatment with ATRA. In conclusion, our data suggest that ATRA administration upregulates CNTF expression in RPE cells.

[Expression of long non-coding RNA NANCI in lung tissues of neonatal mice with hyperoxia-induced lung injury and its regulatory effect on NKX2.1].

OBJECTIVE: To investigate the expression of long non-coding RNA NANCI in lung tissues of neonatal mice with hyperoxia-induced lung injury and its regulatory effect on NKX2.1. METHODS: A total of 48 neonatal C57BL/6J mice were randomly divided into an air group and a hyperoxia group, with 24 mice in each group. Each group was further divided into 7-day, 14-day, and 21-day subgroups, with 8 mice in each subgroup. The mice in the air group were fed in the indoor environment (FiO2=21%) and those in the hyperoxia group were fed in a high-oxygen box (oxygen concentration: >95%). The mice were sacrificed at each time point and lung tissue samples were collected. Hematoxylin and eosin staining was used to observe pathological changes in lung tissues. RT-qPCR and Western blot were used to measure the mRNA and protein expression of NANCI and NKX2.1. RESULTS: The air group had the highest mRNA expression of NANCI and NKX2.1 at 7 days and the same level of mRNA expression at 14 and 21 days. Compared with the air group, the hyperoxia group had significant reductions in the degree of alveolarization and radial alveolar count (RAC) in lung tissues (P<0.05), and in the hyperoxia group, RAC gradually decreased over the time of hyperoxia exposure (P<0.05). The hyperoxia group had significantly lower mRNA and protein expression of NANCI and NKX2.1 than the air group at all time points (P<0.05). In both groups, the relative mRNA and protein expression of NANCI and NKX2.1 gradually decreased over the time of hyperoxia exposure (P<0.05). The expression of NKX2 was positively correlated with that of NANCI (r=0.585, P=0.003), and the expression of NKX2 and NANCI was positively correlated with RAC in the hyperoxia group (r=0.655 and 0.541 respectively, P<0.05). CONCLUSIONS: NANCI may be involved in the development of immature lung tissues. Lung injury is gradually aggravated over the time of hyperoxia exposure. The levels of NANCI and NKX2.1 are associated with the severity of lung injury, suggesting that the NANCI/NKX2.1 target gene signaling pathway might be involved in the development of hyperoxia-induced lung injury in neonatal mice.

Differential expression of long non-coding RNAs in hyperoxia-induced bronchopulmonary dysplasia.

Bronchopulmonary dysplasia (BPD) is a common complication of premature birth that seriously affects the survival rate and quality of life among preterm neonates. Long non-coding RNAs (lncRNAs) have been implicated in many human diseases. However, the role of lncRNAs in the pathogenesis of BPD remains poorly understood. Here, we exposed neonatal C57BL/6J mice to 95% concentrations of ambient oxygen and established a mouse lung injury model that mimicked human BPD. Next, we compared lncRNA and messenger RNA (mRNA) expression profiles between BPD and normal lung tissues using a high-throughput mouse lncRNA + mRNA array system. Compared with the control group, 882 lncRNAs were upregulated, and 887 lncRNAs were downregulated in BPD lung tissues. We validated some candidate BPD-associated lncRNAs by real-time quantitative reverse-transcription polymerase chain reaction analysis in eight pairs of BPD and normal lung tissues. Gene ontology, pathway and bioinformatics analyses revealed that a downregulated lncRNA, namely AK033210, associated with tenascin C may be involved in the pathogenesis of BPD. To the best of our knowledge, our study is the first to reveal differential lncRNA expression in BPD, which provides a foundation for further understanding of the molecular mechanism of BPD development. Copyright © 2016 John Wiley & Sons, Ltd.