Biology subjects

Sgourdou, P.

Publications and source records attributed to Sgourdou, P..

3 recordsLinked to original sources

bioRxiv2026

SilencioM: silencing connected interfering oligonucleotides against MAPT as a potential disease modifying therapeutic for tauopathies

Tauopathies are a diverse group of neurodegenerative diseases whose pathogenesis involves brain accumulation of misfolded, pathological tau (Microtubule Associated Protein Tau, MAPT). More than twenty tauopathies have been identified thus far that collectively impact millions of people worldwide, of which the most common is Alzheimer's disease (AD). Despite substantial efforts to develop drugs for tauopathies, no effective treatments currently exist, highlighting the urgent need for therapeutics to combat these prevalent and ruinous neurodegenerative diseases. Strategies that target tau are likely to have the greatest impact since tau is the proximal cause of their pathogenesis. Small interfering RNAs (siRNAs) have emerged as a powerful class of precision therapeutics that silence disease-causing genes through RNA interference with favorable safety profiles. Delivery challenges are rapidly being addressed, and siRNA-based approaches are poised to transform the therapeutic landscape of neurological diseases. In this study, we describe SilencioM (Silencing connected interfering oligonucleotides against MAPT) and show its efficacy in markedly reducing tau pathology after a single intracerebroventricular injection in PS19 mice, a mouse model of severe tauopathy. SilencioM targets human, primate, rat and mouse ortholog genes; thus, the same compound can proceed from efficacy studies to Investigational New Drug Application (IND)-enabling studies. SilencioM is simple to manufacture and is administered without encapsulation in lipid nanoparticles and without requirements for lipophilic conjugation, making it a promising candidate for further development as a novel therapeutic for tauopathies, including AD.

pathology↗

bioRxiv2024

MIWI arginines orchestrate generation of functional pachytene piRNAs and spermiogenesis

N-terminal arginine (NTR) methylation is a conserved feature of PIWI proteins, which are central components of the PIWI-interacting RNA (piRNA) pathway. The significance and precise function of PIWI NTR methylation in mammals remains unknown. In mice, PIWI NTRs bind Tudor domain containing proteins (TDRDs) that have essential roles in piRNA biogenesis and the formation of the chromatoid body. Using mouse MIWI (PIWIL1) as paradigm, we demonstrate that the NTRs are essential for spermatogenesis through the regulation of transposons and gene expression. Surprisingly, the loss of TDRD5 and TDRKH interaction with MIWI results in defective piRNA amplification, rather than an expected failure of piRNA biogenesis. We find that piRNA amplification is necessary for both transposon control and for sustaining levels of select, nonconserved, pachytene piRNAs that target specific mRNAs required for spermatogenesis. Our findings support the notion that the vast majority of pachytene piRNAs are dispensable, acting as autonomous genetic elements that rely for propagation on MIWI piRNA amplification. MIWI-NTRs also mediate interactions with TDRD6 that are necessary for chromatoid body compaction. Furthermore, MIWI-NTRs promote stabilization of spermiogenic transcripts that drive nuclear compaction, which is essential for sperm formation. In summary, the NTRs underpin the diversification of MIWI protein function. Key pointsO_LIMIWI-NTRs coordinate interactions with TDRDs required for piRNA biogenesis to sustain piRNA amplification C_LIO_LIMIWI-NTRs are necessary for both transposon control and for sustaining levels of select pachytene piRNAs that target specific mRNAs required for spermiogenesis C_LIO_LIMIWI-NTRs mediate interactions with TDRD6 to compact the Chromatoid Body C_LIO_LIMIWI-NTRs underlie stabilization of spermiogenic transcripts that drive nuclear compaction, which is essential for sperm formation C_LI

molecular biology↗

bioRxiv2022

Combined single-cell RNA-seq profiling and enhancer editing reveals critical spatiotemporal controls over thalamic nuclei formation in the murine embryo

The thalamus is the principal information hub of the vertebrate brain, with essential roles in sensory and motor information processing, attention, and memory. The molecular mechanisms regulating the formation of thalamic nuclei are unclear. We apply longitudinal single-cell RNA-sequencing, regional abrogation of Sonic-hedgehog (Shh), and spatial profiling of gene expression to map the developmental trajectories of thalamic progenitors, intermediate progenitors, and post-mitotic neurons as they coalesce into distinct thalamic nuclei. These data reveal that the complex architecture of the thalamus is established early during embryonic brain development through the coordinated action of four cell differentiation lineages derived from Shh-dependent and independent progenitors. We systematically characterize the gene expression programs that define these lineages across time and demonstrate how their disruption upon Shh depletion causes pronounced locomotor impairment resembling infantile Parkinsons disease. These results reveal key principles of thalamic development and provide mechanistic insights into neurodevelopmental disorders resulting from thalamic dysfunction.

neuroscience↗