Nuclear factor-κB (NF-κB) is a transcription factor regulating a wide array of genes mediating numerous cellular processes such as proliferation, differentiation, motility and survival, to name a few. Aberrant activation of NF-κB is a frequent event in numerous cancers, including glioblastoma, the most common and lethal form of brain tumours of glial cell origin (collectively termed gliomas). Glioblastoma is characterized by high cellular heterogeneity, resistance to therapy and almost inevitable recurrence after surgery and treatment. NF-κB is aberrantly activated in response to a variety of stimuli in glioblastoma, where its activity has been implicated in processes ranging from maintenance of cancer stem-like cells, stimulation of cancer cell invasion, promotion of mesenchymal identity, and resistance to radiotherapy. This review examines the mechanisms of NF-κB activation in glioblastoma, the involvement of NF-κB in several mechanisms underlying glioblastoma propagation, and discusses some of the important questions of future research into the roles of NF-κB in glioblastoma.

Fragile X syndrome (FXS) is caused by a repression of the FMR1 gene that codes the Fragile X mental retardation protein (FMRP), an RNA binding protein involved in processes that are crucial for proper brain development. To better understand the consequences of the absence of FMRP, we analyzed gene expression profiles and activities of cortical neural progenitor cells (NPCs) and neurons obtained from FXS patients’ induced pluripotent stem cells (IPSCs) and IPSC-derived cells from FMR1 knock-out engineered using CRISPR-CAS9 technology. Multielectrode array recordings revealed in FMR1 KO and FXS patient cells, decreased mean firing rates; activities blocked by tetrodotoxin application. Increased expression of presynaptic mRNA and transcription factors involved in the forebrain specification and decreased levels of mRNA coding AMPA and NMDA subunits were observed using RNA sequencing on FMR1 KO neurons and validated using quantitative PCR in both models. Intriguingly, 40% of the differentially expressed genes were commonly deregulated between NPCs and differentiating neurons with significant enrichments in FMRP targets and autism-related genes found amongst downregulated genes. Our findings suggest that the absence of FMRP affects transcriptional profiles since the NPC stage, and leads to impaired activity and neuronal differentiation over time, which illustrates the critical role of FMRP protein in neuronal development.

Oligodendrocytes (OLs) are key players in the central nervous system, critical for the formation and maintenance of the myelin sheaths insulating axons, ensuring efficient neuronal communication. In the last decade, the use of human induced pluripotent stem cells (iPSCs) has become essential for recapitulating and understanding the differentiation and role of OLs in vitro. Current methods include overexpression of transcription factors for rapid OL generation, neglecting the complexity of OL lineage development. Alternatively, growth factor‐based protocols offer physiological relevance but struggle with efficiency and cell heterogeneity. To address these issues, we created a novel SOX10‐P2A‐mOrange iPSC reporter line to track and purify oligodendrocyte precursor cells. Using this reporter cell line, we analyzed an existing differentiation protocol and shed light on the origin of glial cell heterogeneity. Additionally, we have modified the differentiation protocol, toward enhancing reproducibility, efficiency, and terminal maturity. Our approach not only advances OL biology but also holds promise to accelerate research and translational work with iPSC‐derived OLs.

Astrocytes play important roles in the function and survival of neuronal cells. Dysfunctions of astrocytes are associated with numerous disorders and diseases of the nervous system, including motor neuron diseases such as amyotrophic lateral sclerosis (ALS). Human-induced pluripotent stem cell (iPSC)-based approaches are becoming increasingly important for the study of the mechanisms underlying the involvement of astrocytes in non-cell autonomous processes of motor neuron degeneration in ALS. These studies must account for the molecular and functional diversity among astrocytes in different regions of the brain and spinal cord. It is essential that the most pathologically relevant astrocyte preparations are used when investigating non-cell autonomous mechanisms of either upper or lower motor neuron degeneration in ALS. Here, we describe the efficient and streamlined generation of human iPSC-derived astrocytes with molecular and biological properties similar to physiological astrocytes in the ventral spinal cord. These induced astrocytes exhibit spontaneous and ATP-induced calcium transients, and lack signs of overt activation. Human iPSC-derived astrocytes with ventral spinal cord features offer advantages over more generic astrocyte preparations for the study of both ventral spinal cord astrocyte biology and the involvement of astrocytes in mechanisms of lower motor neuron degeneration in ALS.

Oligodendrocytes (OLs) are key players in the central nervous system, critical for the formation and maintenance of the myelin sheaths insulating axons, ensuring efficient neuronal communication. In the last decade, the use of human induced pluripotent stem cells (iPSCs) has become essential for recapitulating and understanding the differentiation and role of OLs in vitro . Current methods include overexpression of transcription factors for rapid OL generation, neglecting the complexity of OL lineage development. Alternatively, growth factor-based protocols offer physiological relevance but struggle with efficiency and cell heterogeneity. To address these issues, we created a novel SOX10-P2A-mOrange iPSC reporter line to track and purify oligodendrocyte precursor cells (OPCs). Using this reporter cell line, we analyzed an existing differentiation protocol and shed light on the origin of glial cell heterogeneity. Additionally, we have modified the differentiation protocol, towards enhancing reproducibility, efficiency, and terminal maturity. Our approach not only advances OL biology but holds promise to accelerate research and translational work with iPSC-derived OLs. Main Points: The differentiation of iPSCs in Oligodendrocyte Precursor Cells (OPCs) and Oligodendrocytes (OLs) is a notoriously difficult technique and often displays variable efficiency and cellular heterogeneity. We engineered a novel reporter line carrying the fluorescent protein mOrange under the control of the OL-specific transcription factor SOX10 to track, purify and characterize OLs. By experimenting with diverse differentiation media, we improved the generation of SOX10-positive cells. Consequently, these cells exhibited increased consistency and effectiveness in evolving into myelinating OLs.

The lack of fragile X mental retardation protein (FMRP) protein, due to a repression of the FMR1 gene, causes Fragile X syndrome (FXS), one of the most prevalent forms of syndromic autisms. The FMR1 gene codes for an RNA binding protein involved in the regulation of gene expression through RNA processing, control of local translation, and protein-protein interactions; processes that are crucial for proper brain development. Taking advantage of induced pluripotent stem cells (iPSCs) and CRISPR-Cas9 genome editing technologies, we generated iPSC-derived cortical neural progenitors and cortical neurons from an FMR1 knock-out and patient cell line with the aim of identifying common phenotypes between the two cellular models. Using RNA sequencing, quantitative PCR and multielectrode array approaches, we assessed how the absence of the functional FMR1 gene affects the transcriptional profiles and the activities of iPSC-derived cortical neuronal progenitor cells (NPCs) and neurons with both models. We observed that FMR1 KO and FXS patient cells have a decrease in their mean firing rate; a cellular activity that can also be blocked by tetrodotoxin (TTX) application in wild-type active neurons. Relative to wild-type neurons, in FMR1 KO neurons, increased expression of presynaptic mRNA and transcription factors involved in the forebrain specification and decreased levels of mRNA coding AMPA and NMDA subunits were observed. Intriguingly, 40% of the differentially expressed genes were commonly deregulated between NPCs and differentiating neurons with significant enrichments in FMRP targets and Autism Related Genes found amongst downregulated genes. This implies that an absence of functional FMRP affects transcriptional profiles at the NPC stage, resulting in impaired activity and differentiation of the progenitors into mature neurons over time. These findings from the FMR1 KO lines were also shared with FXS patients’ iPSC-derived cells that also present with an impairment in activity and neuronal differentiation, illustrating the critical role of FMRP protein in neuronal development.