AbstractsBiology & Animal Science

BACKGROUND AND AIM The process of alveolarization is tightly regulated and requires the contribution of different subpopulations of fibroblasts such as myofibroblasts, lipofibroblasts and platelet-derived growth factor receptor alpha (PDGFRalpha)-positive fibroblasts. Each of this fibroblasts subset fulfills certain functions during lung development in a time-dependent manner. In particular PDGFRalpha-positive cells are crucial for alveolar septation and myofibroblasts differentiation. PDGF-A deletion in vivo leads to a disruption of septum formation in mice. Therefore, we aimed to characterize PDGFRalpha-positive fibroblasts specific miRNA and mRNA expression profiles at different time points of lung development. We hypothesized that their phenotype, differentiation capacities and functions might be regulated by the change of expression profiles during the different stages of lung development and homeostasis. RESULTS Lung PDGFRalpha-positive fibroblasts were isolated using magnetic beads/anti-PDGFRalpha antibody positive selection. Using TaqMan low density array analysis we identified 98 significantly regulated miRNAs out of 750 tested miRNAs that exhibited different expression patterns across four time points of lung development. 56 of these miRNAs were up-regulated at P5 vs. W6 and only 16 miRNAs at W6 vs. P5. In silico analysis of these miRNA candidates allowed us to identify their function and gene targets. Subsequent analysis of the PDGFRalpha-positive fibroblasts transcriptome using next-generation sequencing revealed gene candidates differentially regulated during alveolarization and in adulthood. CONCLUSIONS MiRNome and transcriptome dataset analysis showed that the molecular phenotype and functions of pulmonary PDGFRalpha-positive cells greatly differ during the onset of alveolarization, and later in adulthood. Simultaneously, we identified relevant miRNAs and gene candidates which might serve as a basis for “loss or gain of function” analysis. These functional studies are essential to identify new therapeutic targets for structural lung diseases and regenerative medicine. HINTERGRUNDINFORMATION und ZIEL Der Prozess der Alveolarisierung unterliegt einer strengen Regulation. Verschiedene Subpopulationen pulmonaler Fibroblasten wie beispielsweise Myofibroblasten, Lipofibroblasten und platelet-derived growth factor receptor alpha (PDGFRalpha)-positive Fibroblasten sind daran beteiligt. Jeder dieser Fibroblasten Subtypen vollbringt eine zeitabhängige bestimmte Funktion während der Lungenentwicklung. Insbesondere tragen PDGFRalpha-positive Zellen wesentlich zu der Septenbildung und der Differenzierung von Myofibroblasten bei. In vivo Deletion von PDGF-A führt zu einer Störung der Alveolarisierung in Mäusen. Daher liegt das Ziel der vorliegenden Arbeit darin, miRNA- und mRNA-Expressionsprofile PDGFRalpha-positiver Fibroblasten, zu verschiedenen Zeitpunkten der Lungenentwicklung zu bestimmen. Die Hypothese der vorliegenden Arbeit besteht darin, dass der Phänotyp, die Differenzierungsmöglichkeiten und die…