Figure 3. Lgr5+ cell-derived taste bud organoid culture. Source: 67.
Reproduced with permission of Proc Natl Acad Sci USA. (a)
Lgr5+ cells in the taste papilla. (b) Results of FACS
sorting of Lgr5+ cells. (c) Single
Lgr5+ cell (green). (d) Representative images of taste
bud organoids at different days in culture.
3.2 Tissue-derived approach
The commonly used approach of cultivating taste bud organoids is to
obtain the digestive juice of taste bud tissue and then cultivate it.
Both mice and rats can be used as research objects to obtain taste buds
for the cultivation of taste bud organoids. Injecting collagenase and
dispase into the tongue to obtain the tongue epithelium, then separate
the CV papillae, as well as part of the non-taste epithelium without
taste buds[73]. [68]After further digesting the obtained taste
papilla tissue with trypsin, it was mixed with matrigel and inoculated
in a culture plate, and organoids were grown from these tissues (Figure
4). Then, the expression levels of taste bud lineage markers mRNA and
proteins as well as immunofluorescence be used to characterize their
physiological characteristics. The greatest convenience of the
tissue-derived taste bud organoid culture approach is that there is no
need to screen and culture specific cells and omit the step of
single-cell sorting. In addition, the tissues contain other types of
cells, which can better simulate the physiological conditions in the
body and provide a living environment closer to the living body for the
cultivation of organoids. Taste bud organoids from FUCCI2 mice in which
mCherry-hCdt1 (red fluorescence) is expressed during G1 phase while
mVenus-hGem (green fluorescence) is expressed during the S/G2/M phase of
the cell cycle[68]. Another study showed that Trpv4 deficiency
reduced sensitivity to sourness and the expression of type III cells in
taste bud organoid[25]. These results can well prove that taste bud
organoids derived from tissues can be used in research.