The microRNA miR-21 Is a Mediator of FGF8 Action on Cortical COUP-TFI Translation

Abstract

SummaryThe morphogen FGF8 plays a pivotal role in neocortical area patterning through its inhibitory effect on COUP-TFI/Nr2f1 anterior expression, but its mechanism of action is poorly understood. We established an in vitro model of mouse embryonic stem cell corticogenesis in which COUP-TFI protein expression is inhibited by the activation of FGF8 in a time window corresponding to cortical area patterning. Interestingly, overexpression of the COUP-TFI 3′UTR reduces the inhibitory effect of FGF8 on COUP-TFI translation. FGF8 induces the expression of few miRNAs targeting COUP-TFI 3′UTR in silico. We found that the functional inhibition of miR-21 can effectively counteract the inhibitory effect of FGF8 in vitro and regulate COUP-TFI protein levels in vivo. Accordingly, miR-21 expression is complementary to COUP-TFI expression during corticogenesis. These data support a translational control of COUP-TFI gradient expression by FGF8 via miR-21 and contribute to our understanding of how regionalized expression is established during neocortical area mapping.

An Eutherian-Specific microRNA Controls the Translation ofSatb2in a Model of Cortical Differentiation

“…Mouse ES cell corticalization in vitro, cell transfection and analysis were performed as previously described (Terrigno et al, 2018a(Terrigno et al, , 2018b. Human hiPS cells (ATCC-DYS0100 line, American Type Culture Collection) were neuralized according to Chambers at al.…”

Pluripotent Stem Cells for Brain Repair: Protocols and Preclinical Applications in Cortical and Hippocampal Pathologies

“…The positional identity of neural cells obtained by pluripotent cell during in vitro differentiation is often established by the simple study of their neurotransmitter phenotype (Eiraku and Sasai, 2011; Shi et al, 2012; Yu et al, 2014; Shiraishi et al, 2017), or by deeper investigation of their molecular nature through methods of global gene expression analysis (Bertacchi et al, 2013, 2014; Espuny-Camacho et al, 2013; Leemput et al, 2014; Edri et al, 2015; Yao et al, 2017; Terrigno et al, 2018a). However, specific neural subtypes present in different areas of the adult brain show, in addition to distinct gene expression profiles, also defined connectivity patterns, electrophysiological proprieties and morphologies (Cadwell et al, 2015; Fuzik et al, 2015; Tiklová et al, 2019).…”

“…Notably, cortical-like cultures, expressing anterior neural markers (FOXG1 and EMX1/2) and enriched in several cortical cell types (BCL11B, TBR1/2, SATB2, BRN2, and CUX1), can be obtained by simply differentiating PSCs, cultured in suspension as embryoid bodies (Ebs), or as attached monolayer, in a chemically defined minimum medium, devoid of any grow factors (Gaspard et al, 2008; Li et al, 2009; Zeng et al, 2010; Lancaster et al, 2013). However, most authors block endogenous posteriorizing or ventralizing factors (Figure 1) to promote the commitment toward an anterior dorsal fate and enrich the culture in cortical cell types (Eiraku et al, 2008; Gaspard et al, 2008; Mariani et al, 2012; Shi et al, 2012; Bertacchi et al, 2013, 2014; Espuny-Camacho et al, 2013, 2018; Kadoshima et al, 2013; Renner et al, 2013; Yu et al, 2014; Paşca et al, 2015; Sakaguchi et al, 2015; Motono, 2016; Gunhanlar et al, 2017; Sarkar et al, 2018; Terrigno et al, 2018a), including BMP inhibitors (Noggin, BMPR1A-Fc, LDN193189, or Dorsomorphin), WNT inhibitors (Dkk1, IWR-1-endo, 53AH, or WNTC59) and TGFβ inhibitors (Lefty, SB431542). In addition, the default fate of PSC-derived neural progenitors appears to be dorsal, thus fewer protocols include the inhibition of SHH signaling (Gaspard et al, 2008; Yu et al, 2014; Sarkar et al, 2018).…”

“…Furthermore, several groups were able to efficiently generate forebrain GABAergic interneurons from PSCs (Gaspard et al, 2008; Li et al, 2009; Zeng et al, 2010; Falk et al, 2012; Germain et al, 2013; Liu et al, 2013; Maroof et al, 2013; Nicholas et al, 2013; Tornero et al, 2013; Yuan et al, 2015; Liao et al, 2016; Sun et al, 2016; Xu et al, 2016). However, due to the ventral origin of the forebrain interneurons, PSCs committed in culture to dorsal telencephalic fates, such as cortex and hippocampus, generate mainly glutamatergic neurons (Zhang et al, 2001; Bibel et al, 2004; Eiraku et al, 2008; Gaspard et al, 2008, 2009; Bertacchi et al, 2013, 2014; Espuny-Camacho et al, 2013; Yu et al, 2014; Michelsen et al, 2015; Livesey et al, 2016; Motono, 2016; Sarkar et al, 2018; Terrigno et al, 2018a). Since GABA-ergic inhibition is essential for maintaining the balanced activity of cortical neural circuits and for the development of neural network activity (Ben-Ari et al, 2007), grafting of PSC-derived cortical or hippocampal cultures enriched with interneurons could have significant clinical repercussions and should be further investigated.…”

“…The first report of PSC-derived neural progenitors committed to a medial pallial identity was by Sasai and colleagues (Eiraku et al, 2008). Since then, several authors described methods to commit PSC to either choroid plexus or hippocampus (Figures 1, 2; Yu et al, 2014; Sakaguchi et al, 2015; Sarkar et al, 2018; Terrigno et al, 2018a). Most of these protocols share an initial phase of WNT, BMP and TGFβ inhibition, followed by activation of BMP and WNT signaling, by either suppling WNT3a or a small-molecule inhibitor of GSK3 (CHIR).…”