Biology subjects

Morin, N.

Publications and source records attributed to Morin, N..

4 recordsLinked to original sources

bioRxiv2026

RAPTOR-targeted Antisense Oligonucleotides Restrict Pathological mTORC1 Activity in GATOR1-dependent Disease

Loss-of-function mutations in the GATOR1 complex (NPRL2, NPRL3, and DEPDC5) are among the most common genetic causes of epilepsy. These mutations impair amino acid-dependent regulation of mTORC1 and cause hyperactive signaling, neuronal hyperexcitability, astrocytic metabolic remodeling, seizures, and early mortality. Here, we report the development of antisense oligonucleotides (ASOs) targeting RAPTOR, an mTORC1 scaffolding subunit, to correct pathological mTORC1 hyperactivity caused by defective upstream regulation. RAPTOR-targeted ASO treatment reduced RAPTOR expression in mouse and human systems and dampened mTORC1 signaling in GATOR1-deficient models. ASO-mediated RAPTOR reduction rescued neuronal hyperexcitability, corrected astrocytic mitochondrial dysfunction, and suppressed spontaneous seizures in vivo. A single treatment significantly extended longevity across neuronal and astrocytic models of GATOR1 deficiency. Collectively, these findings establish RAPTOR-targeted ASOs as a mechanism-based therapeutic approach that durably corrects cellular and circuit-level consequences of GATOR1 deficiency. By tuning RAPTOR abundance, this strategy provides a therapeutic framework for mTORC1-driven epilepsies and related diseases.

neuroscience↗

bioRxiv2022

eIf2α-regulated translation modulates the early adhesion of mesenchymal-like cells

Cellular invasion is a complex process that requires several interdependent biological mechanisms, which are initiated by changes in adhesion that establish a morphology favorable for migration. Hence, the regulation of adhesion potential is a rate-limiting step in metastasis. Our previous work revealed that de novo translation is necessary to regulate the adhesion of mesenchymal-like cells; however, the underlying translational regulatory mechanism and the identity of newly synthesized proteins needed for the adhesion process remain unidentified. Here, we identify a mechanotransduction pathway linking force-mediated protein unfolding to translational reprogramming via the activation of the integrated stress response (ISR). Specifically, we demonstrate that phosphorylation of eukaryotic translation initiation factor 2 alpha (eIF2) during early adhesion events leads to selective translation of mRNAs encoding proteins critical for adhesion complex formation, mechanosensing, and contractility. These findings uncover a mechanosensitive translational control axis that links intracellular force generation to cell adhesion and stress adaptation, with implications for understanding mesenchymal cell adhesion and morphological behavior

cell biology↗

bioRxiv2021

Functional screen of Inflammatory Bowel Disease genes reveals key epithelial functions

BackgroundGenetic studies have been tremendously successful in identifying genomic regions associated with a wide variety of phenotypes, although the success of these studies in identifying causal genes, their variants, and their functional impacts have been more limited. MethodsWe identified 145 genes from IBD-associated genomic loci having endogenous expression within the intestinal epithelial cell compartment. We evaluated the impact of lentiviral transfer of the open reading frame (ORF) of these IBD genes into the HT-29 intestinal epithelial cell line via transcriptomic analyses. Comparing the genes whose expression was modulated by each ORF, as well as the functions enriched within these gene lists, identified ORFs with shared impacts and their putative disease-relevant biological functions. ResultsAnalysis of the transcriptomic data for cell lines expressing the ORFs for known causal genes such as HNF4a, IFIH1 and SMAD3 identified functions consistent for what is known for these genes. These analyses also identified two major cluster of genes: Cluster 1 contained the known IBD causal genes IFIH1, SBNO2, NFKB1 and NOD2, as well as genes from other IBD loci (ZFP36L1, IRF1, GIGYF1, OTUD3, AIRE and PITX1), whereas Cluster 2 contained the known causal gene KSR1 and implicated DUSP16 from another IBD locus. Our analyses highlight how multiple IBD gene candidates impact on epithelial structure and function, including the protection of the mucosa from intestinal microbiota, and demonstrate that DUSP16, acts a regulator of MAPK activity and contributes to mucosal defense, in part via its regulation of the polymeric immunoglobulin receptor, involved in the protection of the intestinal mucosa from enteric microbiota. ConclusionsThis functional screen, based on expressing IBD genes within an appropriate cellular context, in this instance intestinal epithelial cells, resulted in changes to the cells transcriptome that are relevant to their endogenous biological function(s). This not only helped in identifying likely causal genes within genetic loci but also provided insight into their biological functions. Furthermore, this work has highlighted the central role of intestinal epithelial cells in IBD pathophysiology, providing a scientific rationale for a drug development strategy that targets epithelial functions in addition to the current therapies targeting immune functions.

genetics↗

bioRxiv2017

Initiation of DNA replication requires actin dynamics and formin activity

Nuclear actin influences transcription in a manner dependent on its dynamics of polymerisation and nucleocytoplasmic translocation. Using human somatic cells and transcriptionally-silent Xenopus egg extracts, we show that actin dynamics is also required for DNA replication. We identify many actin regulators in replicating nuclei from Xenopus egg extracts, and show that in human cells, nuclear actin filaments form in early G1 and disassemble prior to S-phase. In either system, treatments that stabilise nuclear actin filaments abrogate nuclear transport and initiation of DNA replication. Mechanistically, actin directly binds RanGTP-importin complexes and disruption of its dynamics hinders cargo release. This prevents both nuclear pore complex (NPC) formation and active nuclear transport, which we show is required throughout DNA replication. Nuclear formin activity is required for two further steps: loading of cyclin-dependent kinase (CDK) and proliferating cell nuclear antigen (PCNA) onto chromatin and initiation of DNA replication. Thus, actin dynamics and formins are involved in several nuclear processes essential for cell proliferation.

cell biology↗