Biology subjects

Ruan, M.

Publications and source records attributed to Ruan, M..

2 recordsLinked to original sources

bioRxiv2021

A lipid-mTORC1 nutrient-sensing pathway regulates animal development by peroxisome-derived hormones

Animals have developed many signaling mechanisms that alter cellular and developmental programs in response to changes in nutrients and their derived metabolites, many of which remain to be understood. We recently uncovered that glucosylceramides, a core sphingolipid, act as a critical nutrient signal for overall amino-acid level to promote development by activating the intestinal mTORC1 pathway. However, how the intestinal GlcCer-mTORC1 activity regulates development throughout the whole body is unknown. Through a large-scale genetic screen, we found that the peroxisomes are critical for antagonizing the GlcCer-mTORC1-mediated nutrient signal. Mechanistically, deficiency of glucosylceramide, inactivation of the downstream mTORC1 activity, or prolonged starvation relocated peroxisomes closer to the intestinal apical region to release peroxisomal-beta-oxidation derived hormones that targeting chemosensory neurons to arrest the animal development. Our data illustrated a new gut-brain axis for orchestrating nutrient-sensing dependent development in Caenorhabditis elegans, which may also explain why glucosylceramide and peroxisome become essential in metazoans.

cell biology↗

bioRxiv2020

Speed modulation of hippocampal theta frequency and power predicts water maze learning

Theta oscillations in the hippocampus have many behavioural correlates, with the magnitude and vigour of ongoing movement being the most salient. Many consider correlates of locomotion with hippocampal theta to be a confound in delineating theta contributions to cognitive processes. But, theory and empirical experiments suggest theta-movement relationships are important if spatial navigation is to support higher cognitive processes. In the current study, we tested if variations in speed modulation of hippocampal theta can predict spatial learning rates in the water maze. Using multi-step regression, we find the magnitude and robustness of hippocampal theta frequency versus speed scaling can predict water maze learning rates. Using generalised linear models, we also demonstrate that speed and water maze learning are the best predictors of hippocampal theta frequency and power. Theta oscillations recorded from the supramammillary area showed much weaker, or non-existent, relationships, which supports the idea that hippocampal theta has specific roles in speed representation and spatial learning. Our findings suggest movement-speed correlations with hippocampal theta frequency may be actively used in spatial learning.

neuroscience↗