Biology subjects

Nutter, L. M. J.

Publications and source records attributed to Nutter, L. M. J..

4 recordsLinked to original sources

bioRxiv2025

Tau deletion results in sex-dependent modulation of synaptic weakening in rat hippocampus

Tangles, a defining characteristic of Alzheimers disease (AD), are composed principally of hyperphosphorylated and misfolded tau species. However, dysregulation of tau precedes tangle formation by many years and is associated with cognitive decline, the best functional correlate of which is synaptic weakening and eventual synaptic loss. Although tau is present at synapses, its normal synaptic function is poorly understood - information vital to the rational development of tau-modifying therapies. Since rats have a greater cognitive repertoire than mice and display more robust signs of tau pathology in AD models, we developed a tau knockout (Mapt-/-) rat to investigate the impact of tau elimination on synaptic function. We observed that long-term depression (LTD), a form of synaptic weakening, is enhanced in the hippocampus of male, but not female, rats. This enhanced LTD was dependent on the synaptic activation of group I metabotropic glutamate receptors and involved altered synaptic actin polymerization. These studies therefore provide mechanistic insights into how tau modulates synaptic function via regulation of the actin cytoskeleton. Our findings are relevant to the understanding of the physiological roles of synaptic tau, the functional consequences of tau-lowering therapies, and the influence of sex in AD susceptibility.

neuroscience↗

bioRxiv2025

A Rosella-PLIN2 Knock-in Mouse Reveals Lipophagy and Immunometabolic Interplay in Atherosclerosis

Cytosolic lipid droplets (LDs) regulate lipid homeostasis, with abnormal LD dynamics linked to metabolic diseases like atherosclerosis. In macrophage foam cells, LDs undergo autophagic degradation via lipophagy, but the extent of this process in vascular smooth muscle cell (VSMC) foam cells remains unclear. To track lipophagy in real time, we developed a Rosella-PLIN2 biosensor by tagging perilipin 2 (PLIN2) with the fluorescent pH-biosensor Rosella. We show that proatherogenic lipoproteins and autophagy activators stimulate lipophagy in human macrophages. Targeting LDs with an LC3 fusion protein or LD-autophagy tethering compounds (LD-ATTECs) selectively enhanced lipophagy, promoting foam cell LD clearance. In an atherosclerosis model, Rosella-PLIN2 accurately tracked lipophagy in arterial foam cells, revealing distinct PLIN2 expression patterns in macrophage and non-leukocyte foam cells. We identified a lipophagy deficiency in VSMC foam cells and demonstrate that enhancing lipophagy promotes LD catabolism in primary VSMC foam cells. TREM2+ macrophages exhibited high lipid content and low lipophagy flux, whereas TREM2- macrophages had low lipid content and high lipophagy flux. Our findings highlight a cell-specific interplay between lipophagy and immunometabolism in arterial foam cells, unveiling novel therapeutic avenues for atherosclerosis. Additionally, the Rosella-PLIN2 model provides a powerful tool for studying LD metabolism, offering new insights into lipid homeostasis and disease mechanisms.

cell biology↗

bioRxiv2020

FORCAST: a fully integrated and open source pipeline to design Cas-mediated mutagenesis experiments

Cas-mediated genome editing has enabled researchers to perform mutagenesis experiments with relative ease. Effective genome editing requires tools for guide RNA selection, off-target prediction, and genotyping assay design. While independent tools exist for these functions, there is still a need for a comprehensive platform to design, view, evaluate, store, and catalogue guides and their associated primers. The Finding Optimizing and Reporting Cas Targets (FORCAST) application integrates existing open source tools such as JBrowse, Primer3, BLAST, bwa, and Silica to create a complete allele design and quality assurance pipeline. FORCAST is a fully integrated software that allows researchers performing Cas-mediated genome editing to generate, visualize, store, and share information related to guides and their associated experimental parameters. It is available from a public GitHub repository and as a Docker image, for ease of installation and portability.

bioinformatics↗

bioRxiv2019

Human and mouse essentiality screens as a resource for disease gene discovery

Although genomic sequencing has been transformative in the study of rare genetic diseases, identifying causal variants remains a considerable challenge that can be addressed in part by new gene-specific knowledge. Here, we integrate measures of how essential a gene is to supporting life, as inferred from the comprehensive viability and phenotyping screens performed on knockout mice by the International Mouse Phenotyping Consortium and from human cell line essentiality screens. We propose a novel, cross-species gene classification across the Full Spectrum of Intolerance to Loss-of-function (FUSIL) and demonstrate that genes in five mutually exclusive FUSIL categories have differing characteristics in the biological processes they regulate, tissue expression levels and human mutation rates. Most notably, Mendelian disease genes, particularly those associated with developmental disorders, are highly overrepresented in the developmental lethal category, representing genes not essential for cell survival but required for organism development. Exploiting this finding, we have screened developmental disorder cases from three independent disease sequencing consortia and identified potentially pathogenic, de novo variants shared in different patients for several developmental lethal genes that have not previously been associated with rare disease. We therefore propose FUSIL as an efficient resource for disease gene discovery.

genomics↗