Biology subjects

Lieberam, I.

Publications and source records attributed to Lieberam, I..

2 recordsLinked to original sources

bioRxiv2022

Pathogenic TDP-43 Disrupts Axon Initial Segment Structure and Neuronal Excitability in a Human iPSC Model of ALS

Dysregulated neuronal excitability is a hallmark of amyotrophic lateral sclerosis (ALS). We sought to investigate how functional changes to the axon initial segment (AIS), the site of action potential generation, could impact neuronal excitability in a human iPSC model of ALS. We found that early (6-week) ALS-related TDP-43G298S motor neurons showed an increase in the length of the AIS, relative to CRISPR-corrected controls. This was linked to neuronal hyperexcitability and increased spontaneous contractions of hiPSC-myofibers in compartmentalised neuromuscular co-cultures. In contrast late (10-week) TDP-43G298S motor neurons showed reduced AIS length and hypoexcitability. At a molecular level aberrant expression of the AIS master scaffolding protein Ankyrin-G, and the AIS-specific voltage-gated ion channels SCN1A (Nav1.1) and SCN8A (Nav1.6) mirrored these dynamic changes in excitability. Finally, at all stages, TDP-43G298S motor neurons showed compromised activity-dependent plasticity of the AIS, further contributing to abnormal excitability. Our results point toward the AIS as an important subcellular target driving changes to neuronal excitability in ALS.

neuroscience↗

bioRxiv2021

Prospective isolation of mouse and human hematopoietic stem cells using Plexin domain containing 2

Numerous strategies exist to isolate hematopoietic stem cells (HSCs) using complex combinations of markers and flow cytometry. However, robust identification of HSCs using imaging techniques is substantially more challenging which has prompted the recent development of HSC reporter mice. To date, none of the molecules used in these reporters have been useful for human HSC identification. Here we report that PLXDC2 is a useful marker for both mouse and human HSCs. Using a green fluorescent protein (GFP) knock-in at the Plxdc2 locus in mice (hereafter denoted as Plxdc2-GFP), we showed that Plxdc2-GFP is highly expressed in HSCs with 1 in 2.8 Plxdc2-GFP+CD150+ cells giving long-term multi-lineage reconstitution in transplantation. Moreover, we developed a novel human PLXDC2 antibody and showed that human PLXDC2+ HSCs have stronger long-term multilineage reconstitution ability compared with PLXDC2- HSCs in a xenograft model. Thus, our study identifies PLXDC2 as a highly relevant molecule in HSC identification, potentially allowing greater purity and live in vivo tracking of these cells. SummaryTo date, few molecules are available for isolation of HSCs across species. The present study shows that PLXDC2 is a highly useful molecule for isolation of HSCs, which works across mouse and human.

cell biology↗