Identification of genes and pathways involved in alveolar epithelial cell differentiation using DNA microarray

Abstract

Scope and Method of Study:

In this project, genes and pathways involved in lung alveolar epithelial cell (AEC) differentiation were identified. In-house printed DNA microarray, data analysis software (RealSpot) and multiple sample hybridization system were developed. These tools were tested at organ and cell level with biological samples from rats. Differentially expressed genes during AEC differentiation were identified using the tested tools and a rat model of hyperoxia exposure and recovery. Data from DNA microarray were verified at mRNA level with real-time PCR, at protein level with Western blot, and at cell level with in vitro/ AEC culture. Pathways based on the verified genes were proposed to elucidate the mechanisms of AEC differentiation.

Findings and Conclusions:

1. At organ level, 147 genes are expressed predominantly in lung by directly comparing transcriptomes of lung, heart, kidney, liver, spleen and brain.

2. At cell level, P2X7 and GABRP are potential type I AEC (AEC I) and type II AEC (AEC II) markers. Among the 1080 AEC I- and 1142 II- specific genes, two AEC I-specific genes, Apo E and transferrin may have protective effect against oxidative stress during hyperoxia exposure.

3. During AEC II differentiation, 6 verified genes may be involved in a regulatory network, which fine-tunes AEC II differentiation through MAPK and TGF? pathways during in vivo hyperoxia exposure and recovery and in vitro AEC culture.