Biology subjects

Terenzio, M.

Publications and source records attributed to Terenzio, M..

4 recordsLinked to original sources

bioRxiv2025

Impairment in axonal translation and cytoplasmic viscosity during aging in sensory neurons

Mitochondria are trafficked along axons and provide the energy required for several intracellular mechanisms including molecular transport and local translation, which is believed to contribute to the homeostasis of the axonal compartment. Decline in mitochondria activity is one of the hallmarks of aging. It is still unclear, though, whether this decline corresponds to a concomitant reduction in the extent of axonal translation during aging. Using live cell imaging of sensory neurons, we found a significant decrease in the number of active mitochondria and the percentage of mitochondria localized to axons in aged mice compared to young mice. This decrease was mirrored by a loss of intracellular ATP as well as an ATP-dependent decrease in axoplasmic viscosity. In addition, the size of G3BP1 positive axonal granules and the number of FMRP axonal granules increased. Cumulatively, we found a functional decrease in the overall level of axonal translation in aged neurons. We were able to rescue this effect by increasing ATP synthesis, which induced a global decrease in axoplasmic viscosity, while promoting RNA granule solubilization and boosting axonal translation. Proteomic analysis of newly synthesized proteins in axons of aged vs young neurons revealed a dysregulation of pathways related to axonal biology and growth. We identified MAP1B and STAT3 as proteins whose axonal local synthesis was impaired in aged axons, and more notably show that this impairment could be rescued by increasing ATP synthesis. We believe that this research sheds light on axonal translation in aged neurons and its relationship with energy sources inside the axonal compartment, possibly presenting an opportunity for future therapeutics.

neuroscience↗

bioRxiv2023

SUPREM: an engineered non-site-specific m6A RNA methyltransferase with highly improved efficiency

m6A RNA methylation plays a key role in RNA processing and translational regulation, influencing both normal physiological and pathological processes. Yet, current techniques for studying RNA methylation struggle to isolate the effects of individual m6A modifications. Engineering of RNA methyltransferases (RNA MTases) could enable development of improved synthetic biology tools to manipulate RNA methylation, but it is challenging due to limited understanding of structure-function relationships in RNA MTases. Herein, using ancestral sequence reconstruction we explore the sequence space of the bacterial DNA methyltransferase EcoGII (M.EcoGII), a promising target for protein engineering due to its lack of sequence specificity and its residual activity on RNA. We thereby created an efficient non-specific RNA MTase termed SUPREM, which exhibits 8-fold higher expression levels, 7 {degrees}C higher thermostability, and 12-fold greater m6A RNA methylation activity compared with M.EcoGII. Immunofluorescent staining and quantitative LC/MS-MS analysis confirmed SUPREMs higher RNA methylation activity compared with M.EcoGII in mammalian cells. Additionally, Nanopore direct RNA sequencing highlighted that SUPREM is capable of methylating a larger number of RNA methylation sites than M.EcoGII. Through phylogenetic and mutational analysis, we identified a critical residue for the enhanced RNA methylation activity of SUPREM. Collectively, our findings indicate that SUPREM holds promise as a versatile tool for in vivo RNA methylation and labeling.

biochemistry↗

bioRxiv2023

Local translation is required for sustained circuit integrity in impaired Wallerian degeneration

After injury, the severed axon separated from the soma activates programmed axon degeneration, an evolutionarily conserved pathway to initiate its degeneration within a day. Conversely, severed projections deficient in programmed axon degeneration remain morphologically preserved with functional synapses for weeks to months after injury. How this synaptic function is sustained remains currently unknown. Here, we demonstrate that dNmnat-mediated over-expression attenuates programmed axon degeneration in distinct neuronal populations. Severed projections remain morphologically preserved for weeks after injury. When evoked, they elicit a postsynaptic behavior which is a readout for preserved synaptic function. We used ribosomal pulldown to isolate translatomes from these projections. Transcriptional profiling revealed several enriched biological classes. Identified candidates were validated in a screen using a novel system to automatically quantify evoked antennal grooming behavior as a proxy for preserved synaptic function. We used RNAi-mediated knockdown to identify mTOR as a mediator of local protein synthesis, and specifically candidates involved in protein ubiquitination and calcium homeostasis, required for preserved synaptic function. Our dataset uncovered several uncharacterized genes linked to human diseases. It may therefore offer insights into novel avenues for therapeutic treatments.

neuroscience↗

bioRxiv2019

DYNLRB1 is Essential for Dynein Mediated Transport and Neuronal Survival

The cytoplasmic dynein motor complex transports essential signals and organelles from the cell periphery to perinuclear region, hence is critical for the survival and function of highly polarized cells such as neurons. Dynein Light Chain Roadblock-Type 1 (DYNLRB1) is thought to be an accessory subunit required for specific cargos, but here we show that it is essential for general dynein-mediated transport and sensory neuron survival. Homozygous Dynlrb1 null mice are not viable and die during early embryonic development. Furthermore, heterozygous or adult knockdown animals display reduced neuronal growth, and selective depletion of Dynlrb1 in proprioceptive neurons compromises their survival. Conditional depletion of Dynlrb1 in sensory neurons causes deficits in several signaling pathways, including {beta}-catenin subcellular localization, and a severe impairment in the axonal transport of both lysosomes and retrograde signaling endosomes. Hence, DYNLRB1 is an essential component of the dynein complex.

neuroscience↗