453 - Gene Expression Signatures in Cord Blood Monocytes After Exposure to Postnatal Hyperoxia

Publication Number: 2441.453

Rochelle Sequeira Gomes, Nemours Children's Hospital, Orlando, FL, United States; Suhita Gayen Nee Betal, Maryland Department of Health, Joppa, MD, United States; sankar Addya, Cooper UniversityHealth Care, Secane, PA, United States; Saurabh Gayen, Lincoln University, Joppa, MD, United States; Zubair H. Aghai, Nemours Children's Hospital, Philadelphia, PA, United States

Background: Postnatal hyperoxia exposure in neonates is known to cause multisystemic cellular injury with altered repair, possibly modulated by altered immune signaling and upregulated or downregulated immune function. The differential gene expression and molecular pathways altered in innate immune cells like monocytes in neonatal hyperoxia are not well understood. This altered immune function may also be associated with long term health disorders following neonatal hyperoxia exposure.

Objective: To study differential gene expression and the molecular pathways altered in neonatal cord blood monocytes following in vitro exposure to 95% compared to 21% oxygen.

Design/Methods: Umbilical cord blood samples were collected at birth and cord blood monocytes were isolated and incubated for 18-20 hours in room air or 95% oxygen to make comparison groups between normoxia and hyperoxia. Total RNA was then isolated, and global gene expression was determined using Affyrmetrix gene chips and human transcriptome array (2.0). Global gene expression was compared between normoxia and hyperoxia groups using transcriptome analysis console software 4.0. We identified differentially expressed genes with fold change ≥1.5 and p-value ≤ 0.05. Ingenuity Pathway Analyis (IPA) Software (Qiagen, Germentown, MD) was used to delineate molecular pathways altered with corresponding physiological and pathological entitites altered.

Results: 14 cord blood samples were exposed to normoxia and hyperoxia, as above. On RNA analysis, a total of 500 genes had altered expression, of which were 171 were upregulated and 329 were downregulated. The top 10 altered genes with fold change are shown in Table 1. In Table 2, top canonical pathways identified are shown, which notably included SUMOylation of DNA which can modulate cellular damage response and function of repair proteins. Top molecular and cellular functions altered were cell-to-cell signaling and interaction and free radical scavenging. Physiological systems altered included organismal survival, tissue development, hematological system development and function, immune cell trafficking and humoral immune response. Table 3 shows the pathological entitities correlating with genes altered.

Conclusion(s): Neonatal cord blood monocytes following in vitro exposure to hyperoxia compared to normoxia show altered gene expression with prominent effects on cellular injury and repair. The pathways identified may help enhance our understanding of long-term diseases associated with neonatal oxygen therapy and altered immune function.

Table 1_Top 10 altered genes with fold change in cord blood monocytes following hyperoxia compared to normoxia
Table 1.pdf

Table 2_Top canonical pathways with hyperoxia in neonatal cord blood monocytes
Table 2.pdf

Table 3: Diseases and Disorders associated with altered genes
Table 3.pdf