Niels Bohr Institutet > Kalender - det sker på NBI > 2010 > Master thesis defense ...

Master thesis defense by Ninna Rossen

Endothelial cell spreading and migration play an important role in angiogenesis, the formation of new blood vessels. Angiogenesis plays a part in many pathologies, e.g., as a prerequisite for malignant tumor growth. Amphiphilic compounds influence cell migration, possibly through their incorporation into the cellular membrane, and propose a novel non-receptor specific regulation of angiogenesis. This thesis investigates the effect of the amphiphilic compound arachidonic acid and shows that it has an effect on endothelial cell spreading and migration. This thesis’s investigation of arachidonic acid’s effect on the spreading of adhering endothelial cells shows that aracidonic acid enhances spreading of adhering cells at low concentrations (20 μM) and inhibits spreading of adhering cells at high concentrations (60-80 μM). Previous literature on cell adhesion has shown adhesion contact area versus time traces display either two or three distinct phases of spreading, each phase being governed by a separate scaling law. The adhesion assay data presented here can be treated to fit both the two and the three phase models. In this thesis, a general analysis method, which introduces a lag-time variable, is proposed. It reconciles the three phase model with the two phase model, such that it agrees with the two state model. This thesis also investigates the migration of endothelial cells using a razor wound assay. The migration traces of individual cells were followed continuously for 24 hours. When arachidonic acid is present in the cells’ media, the leading cells lose their sense of direction, and their traces become less directed and more random than in the control assay.

Endotelcellers spredning og migration spiller en vigtig rolle i angiogenese, som er dannelsen af nye blodkar. Angiogenese spiller en rolle i mange pathologier, f.eks. er det en forudsætning for væksten af maligne tumorer. Amphifile stoffer influerer celle migration, muligvis gennem deres inkorporering i cellens membran, og udgør en ny ikke-receptor specifik regulering af angiogenese. Dette speciale undersøger effekten af det amphifile stof arakidonsyre, og viser at tilstedeværelsen af arakidonsyre påvirker endotelcellernes spredning og migration. Specialets undersøgelser af arakidonsyres effekt på adhererende cellers spredning viser at arakidonsyre fremskynder spredningen af adhererende celler ved lave koncentrationer (20 μM) og bremser spredningen af adhererende celler ved høje koncentrationer (60-80 μM). Tidligere litteratur omhandlende cellespredning viser at cellens adhesionskontaktareal som funktion af tid udviser enten to eller tre faser, hvor hver fase styres af hver deres skalerings lov. De eksperimentelle data for adhesionsassays kan behandles så det passer med både to og tre fase modellen. I dette speciale fremføres en generel analysemetoder, hvori der introduceres en tidsforskydnings variable, som kan få tre fase modellen til at stemme overens med to fase modelen.  Endotelcellers migration undersøges også i specialet ved hjælp af razor wound assays. De enkelte cellers migration blev fulgt nøje over 24 timer. Når arakidonsyre er tilstede i cellernes medie, så  mister de førende celler deres retningssans og deres spor bliver mindre retningsorientered, og mere tilfældige end i de tilsvarende kontrolforsøg der ikke havde arakidonsyre i cellernes medie.

Supervisor: Lene Oddershede