PLURIPOTENT STEM CELLS FROM THE ADULT MOUSE UTRICLE

Abstract

Researchers discovered that cochlear epithelia in mice especially the vestibular one,
contains stem cells that have the capacity to differentiate in sensorial auditory hair
cell progenitors specific to the organ. They are reduced in number as the animal
progresses in age. This process leads to a loss in the regenerative and proliferative
potential of sensorial inner ear epithelia secondary to different injuries. Isolation,
cultivation and than in vitro differentiation of vestibular stem cells could become a
regenerative implant for acquired hearing loss. These were the motives that
determined us to try to isolate, cultivate and finally differentiate vestibular stem cells
from vestibular epithelia.Utricles from 7 days old mice NMRI were harvested, the
otolites were removed, the utricles were trypsinized in order to isolate cells.
Obtained cells were cultivated at 37ºC and 5% CO2 in DMEM with F12 Nutrient
mixture, B27, N2 supplement. Pluripotency of obtained spheres was established with
the help of stem cell markers Nanog and Oct-4. For identification of progenitor cells
we used the marker, which reveals the gene which encodes the protein nestin. In all
experiments we obtained floating colonies called spheres, formed by mitotic
multiplying. For testing the pluripotency of spheres we used Nanog and Oct-4, two
transcription factors that are expressed at high levels in stem cells and that we found
to be expressed in our spheres. The presence of nestin mRNA in cells composing the
spheres showed that these progressed to a progenitor cell stage.We concluded that
utricular epithelia in 7 days old mice contains sufficient stem cells that can be
cultivated and that can be later differentiated.