Stiffness of collagen type I inhibits axon growth of sympathetic neurons: a 3D culture model to study mechanical signals

G F MARTÍNEZ; J FAGETTI; G VIERCI; M BRAUER; N UNSAIN; A RICHERI

Congreso; XXXV Congreso Reunión Anual ? Sociedad Argentina de Investigación en Neurociencia. Modalidad Virtual; 2020

Mechanical signals influence axon growth of both CNS and PNS neurons. Type I collagen(Col-I) has been widely used as a substrate to study axon growth, since it emulates an invivo environment. Here, we evaluated the influence of Col-I stiffness to the extent ofsympathetic axon growth in three dimensions (3D). With this aim, superior cervicalganglion explants from neonatal rats were cultured in soft or stiff Col-I 3D matrices. StiffCol-I 3D matrices were achieved following 4hs of treatment with glycolaldehyde (GA).Sympathetic axon growth was greatly influenced by Col-I stiffness both after 24 and48hs. The main findings were: (1) explants seeded in soft Col-I matrices, formed radiallysymmetric halos composed of an intricate meshwork of neurites; (2) in stiff Col-Imatrices, the neurites fasciculated, and formed smaller and apparently less dense halos;(3) neurites showed limited growth in stiff Col-I matrices evidenced by reduced lengthcompared to those that grew in soft matrices and (4) a loss of growth cones in axonsgrowing in Col-I stiff matrices was also evidenced. Here we showed that a mechanicalproperty of the microenvironment, such as stiffness, can be less favorable to the growthof sympathetic axons. Together these results provide insights to the understanding ofhow growing neurons are affected when they interact mechanically with theirenvironment, an issue that should be considered in tissue engineering and organoidresearch.