Summary Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative condition characterized by the loss of motor neurons. We utilized single-cell transcriptomics to uncover dysfunctional pathways in degenerating motor neurons differentiated from SOD1 E100G ALS patient-derived induced pluripotent stem cells (iPSCs) and respective isogenic controls. Differential gene expression and network analysis identified activation of developmental pathways and core transcriptional factors driving the ALS motor neuron gene dysregulation. Specifically, we identified activation of SMAD2, a downstream mediator of the transforming growth factor β (TGF-β) signaling pathway as a key driver of SOD1 iPSC-derived motor neuron degeneration. Importantly, our analysis indicates that activation of TGFβ signaling may be a common mechanism shared between SOD1, FUS, C9ORF72, VCP, and sporadic ALS motor neurons. Our results demonstrate the utility of single-cell transcriptomics in mapping disease-relevant gene regulatory networks driving neurodegeneration in ALS motor neurons. We find that ALS-associated mutant SOD1 targets transcriptional networks that perturb motor neuron homeostasis.

No abstract

RNA processing is a fundamental mode of gene regulation that is perturbed in a variety of diseases including cancer and neurodegenerative disorders. RNA-binding proteins (RBPs) regulate key aspects of RNA processing including alternative splicing, mRNA degradation and localization by physically binding RNA molecules. Current methods to map these interactions, such as CLIP, rely on purifying single proteins at a time. We have developed a new method (ePRINT) to map RBP-RNA interaction networks on a global scale without purifying individual RBPs. ePRINT allows precise mapping of the 5 prime end of the RBP binding site, and can uncover direct and indirect targets of an RBP of interest. Importantly, ePRINT can also uncover RBPs that are differentially activated between cell fate transitions, for instance, as neural progenitors differentiate into neurons. Given its versatility, ePRINT has vast application potential as an investigative tool for RNA regulation in development, health and disease.

speaking and phone use. Staff were unable to hold face-toface family meetings and families were unable to be at the bedside which would, in normal times, enable them to be part of the patient's hospital journey. Inevitably, this all led to an increased volume of phone calls. To try to solve some of these issues, it was decided that a dedicated team was needed to establish open lines of communication between patient, family and staff. A group of senior nurses from across the hospital were brought together to form the Critical Care Family Liaison Team (FLT). FLT now give coordinated information and are the first point of contact for families. Interventions include using technology such as FaceTime and Zoom to allow 'virtual visiting', conference calling for family updates, bedside photographs, voice recordings sent in by families and music playlists. The role for the FLT has evolved; the team was set up rapidly at the start of lockdown and members were in their new roles within a week. Daily verbal feedback was gathered from the medical team and interventions changed as necessary. It is difficult to assess what the situation would have been without this innovation. Formal feedback was requested from all staff members working in Critical Care and from patients and their families. Qualitative and 5 point likert scale responses have been positive. Further data collection and feedback is ongoing to ensure the service continues to evolve as we move towards a new normal.