Modulation of Small RNA Signatures in Schwann-Cell-Derived Extracellular Vesicles by the p75 Neurotrophin Receptor and Sortilin

Abstract

Schwann cells (SCs) are the main glial cells of the peripheral nervous system (PNS) and are known to be involved in various pathophysiological processes, such as diabetic neuropathy and nerve regeneration, through neurotrophin signaling. Such glial trophic support to axons, as well as neuronal survival/death signaling, has previously been linked to the p75 neurotrophin receptor (p75NTR) and its co-receptor Sortilin. Recently, SC-derived extracellular vesicles (EVs) were shown to be important for axon growth and nerve regeneration, but cargo of these glial cell-derived EVs has not yet been well-characterized. In this study, we aimed to characterize signatures of small RNAs in EVs derived from wild-type (WT) SCs and define differentially expressed small RNAs in EVs derived from SCs with genetic deletions of p75NTR (Ngfr−/−) or Sortilin (Sort1−/−). Using RNA sequencing, we identified a total of 366 miRNAs in EVs derived from WT SCs of which the most highly expressed are linked to the regulation of axonogenesis, axon guidance and axon extension, suggesting an involvement of SC EVs in axonal homeostasis. Signaling of SC EVs to non-neuronal cells was also suggested by the presence of several miRNAs important for regulation of the endothelial cell apoptotic process. Ablated p75NTR or sortilin expression in SCs translated into a set of differentially regulated tRNAs and miRNAs, with impact in autophagy and several cellular signaling pathways such as the phosphatidylinositol signaling system. With this work, we identified the global expression profile of small RNAs present in SC-derived EVs and provided evidence for a regulatory function of these vesicles on the homeostasis of other cell types of the PNS. Differentially identified miRNAs can pave the way to a better understanding of p75NTR and sortilin roles regarding PNS homeostasis and disease.

Sortilin regulates blood–brain barrier integrity

“…Wild-type (WT) Sprague Dawley rats were obtained from Janvier laboratories, while Sort1−/− Sprague Dawley rats (KO) were purchased from Horizon Discovery and custom made, respectively, for breeding at the Animal Facility at Aarhus University. Sort1−/− is a 5 basepair deletion in exon 9 resulting in a stop codon, with subsequent complete destruction of the Vps10p-domain folding [30]. No mRNA splice variants or protein fragments were detected by sequencing or western blot analysis.…”

Production and internalization of extracellular vesicules in normal and under conditions of hyperglycemia and insulin resistance

“…Выявлено, что ряд микроРНК, секретируемых в составе ВВ при экспериментальном или клиническом диабетах, вовлечены в патогенез диабетической ретинопатии и нейропатии и в перспективе также могут быть полезны в качестве ранних и достоверных маркеров этих осложнений [47][48][49][50]. Кроме того, вышеперечисленные маркеры могут быть использованы для контроля эффективности терапии данных осложнений [51].…”

Metabolic Control of Sensory Neuron Survival by the p75 Neurotrophin Receptor in Schwann Cells

“…Historically, hyperglycemic conditions, and/or ischemic and hypoxic conditions from vascular modifications were accepted as the most probable cause of axonal degeneration in DN. However, clinical trials have found glycemic control is not sufficient to prevent DN from occurring, suggesting that progression of DN is also mediated by other factors (M. C. Perez-Matos, Gonçalves, Yan, et al, 2020).…”