Biology subjects

Jarretou, G.

Publications and source records attributed to Jarretou, G..

3 recordsLinked to original sources

bioRxiv2025

CSF1R regulates monocyte subset differentiation and intracellular metabolism.

Monocytes are key circulating effectors of vascular homeostasis, innate immunity and inflammation. Following their generation in mouse bone marrow, classical (Ly6Chigh) monocytes are mobilized into the blood circulation where they mature into non-classical (Ly6Clow) patrolling monocytes or are recruited into peripheral tissues where they differentiate into tissue resident or inflammatory macrophages. Monocytes and macrophages express CSF1R (CD115), the receptor for lineage-specific growth factors CSF1 and IL34. Here, we report that acute CSF1R blockade or genetic deletion negatively interferes with monocyte intracellular metabolism and reduces blood Ly6Clow monocytes in part by blunting differentiation of Ly6Chigh monocytes. Based upon lineage-specific deletion of GFPT1 (Glutamine-Fructose-6-Phosphate Transaminase 1), the hexosamine biosynthetic pathway (HBP) is identified as a novel regulator of CSF1R expression and monocyte subset diversity. Our findings provide new insights into the link between CSF1R signaling, metabolic regulation, and monocyte survival and differentiation.

immunology↗

bioRxiv2024

Rapid microfluidic perfusion system enables controlling dynamics of intracellular pH regulated by Na+/H+ exchanger NHE1

pH regulation of eukaryotic cells is of crucial importance and influences different mechanisms including chemical kinetics, buffer effects, metabolic activity, membrane transport and cell shape parameters. In this study, we develop a microfluidic system to rapidly and precisely control a continuous flow of ionic chemical species to acutely challenge the intracellular pH regulation mechanisms and confront predictive models. We monitor the intracellular pH dynamics in real-time using pH-sensitive fluorescence imaging and establish a robust mathematical tool to translate the fluorescence signals to pH values. By varying flow rate across the cells and duration for rinsing process, we manage to tweak the dynamics of intracellular pH from a smooth recovery to either an overshooting state, where the pH goes excitedly to a maximum value before decreasing to a plateau, or an undershooting state where the pH is unable to recover to [~] 7. We believe our findings will provide more insight into intracellular regulatory mechanisms and promote the possibility of exploring cellular behavior in the presence of strong gradients or fast changes in homogeneous conditions.

bioengineering↗

bioRxiv2022

Biological fractionation of lithium isotopes by cellular Na+/H+ exchangersunravels fundamental transport mechanisms.

Lithium (Li) has a wide range of uses in science, medicine and industry but its isotopy is underexplored, except in nuclear science and in geoscience. 6Li and 7Li isotopic ratio exhibits the second largest variation on Earths surface and constitutes a widely used tool for reconstructing past oceans and climates. As large variations have been measured in mammalian organs, plants or marine species, and as 6Li elicits stronger effects than natural Li (~95% 7Li) a central issue is the identification and quantification of biological influence of Li isotopes distribution. We show here that membrane ion channels and Na+-Li+/H+ exchangers (NHEs), strongly fractionate Li isotopes. This systematic 6Li enrichment is driven by membrane potential for channels, and by intracellular pH for NHEs, where it displays cooperativity, a hallmark of dimeric transport. Evidencing that transport proteins discriminate between isotopes differing by one neutron, opens new avenues for transport mechanisms, Li physiology, and paleoenvironments.

biochemistry↗