Open AccessConstitutive activation of CTNNB1 results in a loss of spermatogonial stem cell activity in mice
Author(s) -
Alexandre Boyer,
Xiangfan Zhang,
Adrien Levasseur,
Nour Abou Nader,
G St-Jean,
Makoto Nagano,
Derek Boerboom
Publication year - 2021
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0251911
Subject(s) - wnt signaling pathway , progenitor cell , biology , stem cell , germ cell , spermatogenesis , microbiology and biotechnology , progenitor , transplantation , transgene , cell fate determination , genetically modified mouse , cell , gene , signal transduction , genetics , transcription factor , medicine , endocrinology
Spermatogenesis requires that a careful balance be maintained between the self-renewal of spermatogonial stem cells (SSCs) and their commitment to the developmental pathway through which they will differentiate into spermatozoa. Recently, a series of studies employing various in vivo and in vitro models have suggested a role of the wingless-related MMTV integration site gene family/beta-catenin (WNT/CTNNB1) pathway in determining the fate of SSCs. However, conflicting data have suggested that CTNNB1 signaling may either promote SSC self-renewal or differentiation. Here, we studied the effects of sustained CTNNB1 signaling in SSCs using the Ctnnb1 tm1Mmt/+ ; Ddx4 -Cre Tr/+ (Δ Ctnnb1 ) mouse model, in which a stabilized form of CTNNB1 is expressed in all germ cells. Δ Ctnnb1 mice were found to have reduced testis weights and partial germ cell loss by 4 months of age. Germ cell transplantation assays showed a 49% reduction in total functional SSC numbers in 8 month-old transgenic mice. In vitro , Thy 1-positive undifferentiated spermatogonia from Δ Ctnnb1 mice formed 57% fewer clusters, which was associated with decreased cell proliferation. A reduction in mRNA levels of genes associated with SSC maintenance ( Bcl6b , Gfra1 , Plzf ) and increased levels for markers associated with progenitor and differentiating spermatogonia ( Kit , Rarg , Sohlh1 ) were detected in these cluster cells. Furthermore, RNAseq performed on these clusters revealed a network of more than 900 genes regulated by CTNNB1, indicating that CTNNB1 is an important regulator of spermatogonial fate. Together, our data support the notion that CTNNB1 signaling promotes the transition of SSCs to undifferentiated progenitor spermatogonia at the expense of their self-renewal.