bioRxiv Science⌕ Search

Biology subjects

Tietz, J.

Publications and source records attributed to Tietz, J..

2 recordsLinked to original sources

Multi-omic characterization of human sural nerves acrosspolyneuropathies

Diseases of peripheral nerves termed polyneuropathies (PNPs) are common, mechanistically heterogeneous, and challenging to diagnose. Here, we integrated single nuclei transcriptomics of peripheral nerves from 33 human PNP patients and four controls (365,708 nuclei) with subcellular spatial transcriptomics. We identified novel and human-specific nerve cell type markers including unexpectedly heterogeneous perineurial fibroblasts. All PNPs shared a loss of myelinating and an increase in repair Schwann cells and endoneurial lipid-associated macrophages. Transcriptional changes affected multiple cells outside of the endoneurium across PNPs, suggesting PNPs as pan-nerve diseases. Spatially, PNPs showed a previously unknown perineurial hyperplasia and fibrotic dispersion and this was most pronounced in immune-mediated PNPs. Single cell transcriptomics supported the differential diagnosis of PNPs with potential for future unbiased diagnostic classification. One-sentence summaryThe first large-scale integrated single cell and spatial transcriptomic characterization of human peripheral nerves identifies novel cell markers and unexpected heterogeneity of perineurial cells, reveals polyneuropathies as pan-nerve diseases, and shows that single cell transcriptomics hold potential for unbiased nerve disease classification.

neuroscience↗

Single-cell transcriptomic changes in oligodendrocytes and precursors derived from Parkinson's disease patient-iPSCs with LRRK2-G2019S mutation

Despite extensive research, the contribution of the LRRK2 p.G2019S mutation to Parkinsons disease (PD) remains unclear. Recent findings indicate oligodendrocytes (ODCs) and their progenitors are vulnerable in PD pathogenesis. Notably, oligodendrocyte precursor cells (OPCs) exhibit high endogenous expression of LRRK2. We induced PD patient-iPSCs with the LRRK2 p.G2019S mutation into oligodendroglial lineages and performed single-cell RNA sequencing. Cell type composition analysis revealed an increase in OPCs, proliferating OPCs and ciliated ependymal cells in LRRK2 lines, all of which are characterized by LRRK2 expression. Differential expression analysis revealed transcriptomic changes in several pathways, including down-regulation of genes related to myelin assembly in ODCs, semaphorin-plexin pathway in OPCs, and cilium movement in proliferating OPCs. Cell-cell communication analysis identified significant alterations in several signaling pathways including a deactivation of PSAP signaling and an activation of MIF signaling in LRRK2 lines. Additionally, we observed an overall increase in SEMA6 signaling communication in LRRK2 cell lines; however, OPCs derived from these LRRK2 lines specifically lost SEMA6 signaling due to a down-regulation of SEMA6A and PLXNA2. Pseudotemporal trajectory analysis revealed that SHH had significantly altered expression along the pseudotime, accompanied by higher expression levels in LRRK2 lines. We propose that dysfunctional semaphorin-plexin signaling, along with cilia movement and SHH signaling, might represent early events in PD pathology.

neuroscience↗