Biology subjects

Malki, S.

Publications and source records attributed to Malki, S..

3 recordsLinked to original sources

bioRxiv2025

Selective GSK3α Inhibition Promotes Self-Renewal Across Different Stem Cell States

Pan-GSK3/{beta} inhibition promotes stem cell self-renewal through activation of WNT/{beta}-catenin signaling, but its broad effects complicate the precise control of stem cell states. Here, we show that selective inhibition of GSK3 with BRD0705 supports the long-term self-renewal of mouse embryonic stem cells (ESCs), epiblast stem cells (EpiSCs), and neural stem cells (NSCs), independent of {beta}-catenin signaling. When combined with the tankyrase inhibitor IWR1, BRD0705 broadly supports the maintenance of diverse pluripotent stem cell states, including ESCs, EpiSCs, and formative pluripotent stem cells. This BRD0705/IWR1 cocktail enables stable co-culture of naive ESCs and primed EpiSCs while preserving their distinct molecular and functional identities. Single-cell transcriptomics, epigenomic profiling, and functional assays confirm sustained lineage-specific features across stem cell types. These findings demonstrate that selective GSK3 inhibition enhances stemness by buffering against differentiation cues and promoting intrinsic self-renewal capacity. This work identifies GSK3 as a key regulator of self-renewal across distinct stem cell states and establishes a versatile culture system with broad applications. In BriefWang et al. demonstrate that selective GSK3 inhibition with BRD0705 supports self-renewal of pluripotent and neural stem cells. Combined with IWR1, it enables long-term co-culture of naive and primed stem cells while preserving their distinct molecular and functional identities. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=181 HEIGHT=200 SRC="FIGDIR/small/653860v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@4e371eorg.highwire.dtl.DTLVardef@104b287org.highwire.dtl.DTLVardef@164bd96org.highwire.dtl.DTLVardef@daf1ba_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIGSK3 inhibition by BRD0705 promotes self-renewal of ESCs, EpiSCs, and NSCs C_LIO_LIBRD0705/IWR1 enables long-term co-culture of ESCs and EpiSCs C_LIO_LICo-cultured ESCs and EpiSCs retain distinct naive or primed identities C_LIO_LIBRD0705 preserves stem cell states independently of {beta}-catenin signaling C_LI

cell biology↗

bioRxiv2023

Cnot3 is required for male germ cell development and spermatogonial stem cell maintenance

The foundation of spermatogenesis and lifelong fertility is provided by spermatogonial stem cells (SSCs). SSCs divide asymmetrically to either replenish their numbers (self-renewal) or produce undifferentiated progenitors that proliferate before committing to differentiation. However, regulatory mechanisms governing SSC maintenance are poorly understood. Here, we show that the CCR4-NOT mRNA deadenylase complex subunit CNOT3 plays a critical role in maintaining spermatogonial populations in mice. Cnot3 is highly expressed in undifferentiated spermatogonia, and its deletion in spermatogonia resulted in germ cell loss and infertility. Single cell analyses revealed that Cnot3 deletion led to the de-repression of transcripts encoding factors involved in spermatogonial differentiation, including those in the glutathione redox pathway that are critical for SSC maintenance. Together, our study reveals that CNOT3 - likely via the CCR4-NOT complex - actively degrades transcripts encoding differentiation factors to sustain the spermatogonial pool and ensure the progression of spermatogenesis, highlighting the importance of CCR4-NOT-mediated post-transcriptional gene regulation during male germ cell development. HighlightsO_LICnot3 is predominantly expressed in undifferentiated spermatogonia, and its expression decreases in later stages. C_LIO_LIConditional deletion of Cnot3 leads to total germ cell loss and male infertility. C_LIO_LICNOT3 represses transcripts encoding factors involved in spermatogonial differentiation. C_LIO_LICNOT3 protects spermatogonial stem cells maintenance via GSH/redox pathway. C_LI Graphical AbstractCnot3 promotes SSC self-renewal by balancing ROS production via the regulation of GSH production O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/562256v1_ufig1.gif" ALT="Figure 1"> View larger version (37K): org.highwire.dtl.DTLVardef@3afef9org.highwire.dtl.DTLVardef@139cb19org.highwire.dtl.DTLVardef@1450c47org.highwire.dtl.DTLVardef@293300_HPS_FORMAT_FIGEXP M_FIG C_FIG

developmental biology↗

bioRxiv2019

Evading non-essential fetal oocyte attrition maximizes the ovarian reserve

Female reproductive success depends on the size and quality of a finite ovarian reserve. Paradoxically, mammals such as mice and humans eliminate up to 80% of the initial oocyte pool during development through the enigmatic process of fetal oocyte attrition (FOA). Here we report that the combined inhibition of retrotransposon L1 reverse transcriptase and the Chk2-dependent DNA damage checkpoint prevents FOA, thus preserving the entire fetal oocyte population. Remarkably, reverse transcriptase inhibitor AZT-treated Chk2 mutant oocytes initially accumulate, but subsequently resolve L1-instigated genotoxic threats and differentiate, resulting in a maximized functional ovarian reserve. We conclude that FOA is a consequence of genotoxic stress that acts to preserve oocyte genome integrity, and is not an obligatory developmental program for oogenesis.

developmental biology↗