engleski

Hippocampal Filopodia but not Growth Cones can Climb Over 600 nm Steps

Guidance molecules, such as Sema3A or Netrin-1, can induce growth cone repulsion or attraction in the presence of a flat surface, but very little is known of the action of guidance molecules in the presence of obstacles. In order to address this issue, we analysed the action of Netrin-1 molecules in the presence of patterned polydimethylsiloxane (PDMS) surfaces with lines with a height varying from 100 to 600 nm. Filopodia can crawl over these lines easily, but not neurites. Indeed axons and thick dendrites are able to cross lines with a height of 100 nm, but progressively less when the line height is increased. When neurons are grown for 3 days over patterned surfaces it was possible to label selectively axons with axonal neurofilament marker SMI 312 and dendrites with microtubule associated protein 2 (MAP2): axons and dendrites do not differ in their ability to cross lines with a height varying from 100 to 600 nm. When axons and dendrites grow along lines, a clear staining for the adhesion marker paxillin was observed, but not when neurites cross the lines.

guidance molecules ; growth cone

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