Pachernegg, S. | bioRxiv Science

bioRxiv2023

COUP-TFII regulates early bipotential gonad signaling and commitment to ovarian progenitors

The absence of expression of the Y-chromosome linked testis-determining gene SRY in early supporting gonadal cells (ESGC) of bipotential gonads leads to ovarian development. However, genetic variants in NR2F2/COUP-TFII represent a novel cause of SRY-negative 46,XX testicular/ovotesticular differences of sex development (T/OT-DSD). Thus, we hy-pothesized that COUP-TFII is part of the ovarian developmental network. We examined NR2F2/COUP-TFII expression and the genetic network under its regulation in human gonadal cells by analyzing single cell RNA-sequencing datasets of fetal gonads, differentiating induced pluripotent stem cells into bipotential gonad-like cells in vitro, and generating a NR2F2 knockout (KO) in the human granulosa-like cell line COV434. NR2F2 expression is highly upregulated during the bipotential gonad development, being detected in ESGCs. We identified that NR2F2 ablation in COV434 cells downregulated markers of ESGC and pre-granulosa cells, suggesting that COUP-TFII has a role in maintaining a multipotent state necessary for commitment to the ovarian development. We propose that impairment of COUP-TFII function may disrupt the transcriptional plasticity of ESGCs and instead drive them into commitment to the testicular pathway.

developmental biology↗

bioRxiv2023

Distinctive in vitro phenotypes in iPSC-derived neurons from patients with gain- and loss-of-function SCN2A developmental and epileptic encephalopathy

SCN2A encodes NaV1.2, an excitatory neuron voltage-gated sodium channel and major monogenic cause of neurodevelopmental disorders, including developmental and epileptic encephalopathies (DEE) and autism. Clinical presentation and pharmocosensitivity vary with nature of SCN2A variant dysfunction with gain-of-function (GoF) cases presenting with pre- or peri-natal seizures and loss-of-function (LoF) patients typically having infantile spasms after 6 months of age. Here, we established and assessed patient induced pluripotent stem cell (iPSC) - derived neuronal models for two recurrent SCN2A DEE variants with GoF R1882Q and LoF R853Q associated with early- and late-onset DEE, respectively. Patient-derived iPSC lines were differentiated using a Neurogenin-2 overexpression yielding populations of cortical-like glutamatergic neurons. Electrophysiological and transcriptomic profiles were assessed after 2-4 weeks in culture. Increased neuronal activity at both cellular and network level was observed for R1882Q iPSC-derived neurons at three weeks of differentiation. In contrast, R853Q neurons showed only subtle changes in excitability after four weeks in vitro. In alignment with the reported efficacy in some GoF SCN2A patients, phenytoin (sodium channel blocker) reduced excitability of neurons to the control levels in R1882Q neuronal cultures. Transcriptomic alterations in neurons were detected for each variant and convergent pathways pointed at the shared mechanisms underlying SCN2A DEE.

neuroscience↗