Wnt- and glutamate-receptors orchestrate stem cell dynamics and asymmetric cell division

Abstract

The Wnt-pathway is part of a signalling network that regulates many aspects of cell biology. Recently we discovered crosstalk between AMPA/Kainate-type ionotropic glutamate receptors (iGluRs) and the Wnt-pathway during the initial Wnt3a-interaction at the cytonemes of mouse embryonic stem cells (ESCs). Here, we demonstrate that this crosstalk persists throughout the Wnt3a-response in ESCs. Both AMPA- and Kainate-receptors regulate early Wnt3a-recruitment, dynamics on the cell membrane, and orientation of the spindle towards a Wnt3a-source at mitosis. AMPA-receptors specifically are required for segregating cell fate components during Wnt3a-mediated asymmetric cell division (ACD). Using Wnt-pathway component knockout lines, we determine that Wnt co-receptor Lrp6 has particular functionality over Lrp5 in cytoneme formation, and in facilitating ACD. Both Lrp5 and 6, alongside pathway effector β-catenin act in concert to mediate the positioning of the dynamic interaction with, and spindle orientation to, a localized Wnt3a-source. Wnt-iGluR crosstalk may prove pervasive throughout embryonic and adult stem cell signalling.

LSD1 controls a nuclear checkpoint in Wnt/β-Catenin signaling to regulate muscle stem cell self-renewal

“…During development and to preserve tissue homeostasis, many types of stem cells rely on Wnt/β-catenin signaling to set the balance between self-renewal and differentiation by promoting asymmetric cell division (Chai et al, 2022; Garcin and Habib, 2017; Junyent et al, 2021; Kaur et al, 2020; Sun et al, 2021). In embryonic stem cells, Wnt-coreceptors and β-catenin control the orientation of the mitotic spindle to favor asymmetric division (Junyent et al, 2021).…”

“…During development and to preserve tissue homeostasis, many types of stem cells rely on Wnt/β-catenin signaling to set the balance between self-renewal and differentiation by promoting asymmetric cell division (Chai et al, 2022; Garcin and Habib, 2017; Junyent et al, 2021; Kaur et al, 2020; Sun et al, 2021). In embryonic stem cells, Wnt-coreceptors and β-catenin control the orientation of the mitotic spindle to favor asymmetric division (Junyent et al, 2021). Since both LSD1 and β-catenin promote asymmetric division and since both were shown to activate the MyoD CER (Pan et al, 2015; Scionti et al, 2017), we investigated whether LSD1 function could be linked to Wnt/β-catenin signaling.…”

“…Cells were analyzed using flow cytometry (FACS Cantoll). For Wnt3A-dependent cell division assay, freshly isolated CTRL SC or LSD1 SCiKO MuSCs were exposed to Wnt3A-coupled to beads and analyzed as previously described (15).…”

“…For demethylase assay, 15 cm plates containing 70-80% confluent HEK 293T cells were transfected with pCMV-LSD1 flag or pCMV-LSD1 K661A flag or pCMV-LSD1 K661A W754A Y761A flag or pCMV-GFP (CTRL) after 24h incubation, protein extraction has been performed. For Wnt3A-dependent cell division assay, freshly isolated CTRL SC or LSD1 SCiKO MuSCs were transfected with an shRNA against β-catenin or a wild-type -β-catenin fused with mCherry respectively, after 24h, cells were exposed to Wnt3A-coupled to beads and analyzed as previously described (15).…”

Non-Classical Intercellular Communications: Basic Mechanisms and Roles in Biology and Medicine

“…Wnt co-receptors Lrp5 and Lrp6, in concert with β-catenin, mediated dynamic interaction and spindle orientation with respect to the localized Wnt3a source. These data suggest that the Wnt-iGluR crosstalk may be involved in signaling not only in embryonic, but also in adult stem cells [ 159 , 160 ].…”