Biology subjects

FLEURIOT, L.

Publications and source records attributed to FLEURIOT, L..

4 recordsLinked to original sources

bioRxiv2021

Lysophosphatidylcholine induces heat pain hypersensitivity in obese mice fed with a high-fat diet through activation of peripheral Acid-Sensing Ion Channel 3

Diet induced obesity is one of the major causes of obesity, which affects 13% of the worlds adult population. Obesity is correlated to chronic pain regardless of other components of the metabolic syndrome. Our study focuses on investigating the effect of high-fat diet induced obesity on peripheral sensory neurons activity and pain perception, followed by deciphering the underlying cellular and molecular mechanisms that involve Acid-Sensing Ion Channel 3 (ASIC3). We show here that heat sensitive C-fibers from mice made obese by consumption of a high-fat diet exhibited an increased activity during baseline and upon heating. Obese mice showed long-lasting heat pain hypersensitivity once obesity was well established, while mechanical sensitivity was not affected. We found that the serum of obese mice was enriched in lysophosphatidylcholine (LPC) species (LPC16:0, LPC18:0 and LPC18:1), which activate ASIC3 channels and increased peripheral neuron excitability. Genetic deletion and in vivo pharmacological inhibition of ASIC3 protected and rescued mice from obesity-induced thermal hypersensitivity. Our results identify ASIC3 channels in DRG neurons and circulating LPC species that activate them as a mechanism contributing to heat pain hypersensitivity associated with high-fat diet induced obesity.

neuroscience↗

bioRxiv2020

Docosahexaenoic fatty acid-containing phospholipids affect plasma membrane susceptibility to disruption by bacterial toxin-induced macroapertures

Metabolic studies and animal knockout models point to the critical role of polyunsaturated docosahexaenoic acid (22:6, DHA)-containing phospholipids (PLs) in physiology. Here, we study the impact of DHA-PLs on the dynamics of transendothelial cell macroapertures (TEMs) tunnels triggered by the RhoA GTPase inhibitory exotoxin C3 from Clostridium botulinum. Through lipidomic analyses, we show that primary human umbilical vein endothelial cells (HUVECs) subjected to DHA-diet undergo a 6-fold DHA-PLs enrichment in plasma membrane at the expense of monounsaturated OA-PLs. In contrast, OA-diet had almost no effect on PLs composition. Consequently, DHA treatment increases the nucleation rate of TEMs by 2-fold that we ascribe to a reduction of cell thickness. We reveal that the global transcellular area of cells remains conserved through a reduction of the width and lifetime of TEMs. Altogether, we reveal a homeostasis between plasma membrane DHA-PLs content and large-scale membrane dynamics.

cell biology↗

bioRxiv2020

UBTD1 regulates ceramide balance and endolysosomal positioning to coordinate EGFRsignaling

To adapt in an ever-changing environment, cells must integrate physical and chemical signals and translate them into biological meaningful information through complex signaling pathways. By combining lipidomic and proteomic approaches with functional analysis, we have shown that UBTD1 (Ubiquitin domain-containing protein 1) plays a crucial role in both the EGFR (Epidermal Growth Factor Receptor) self-phosphorylation and its lysosomal degradation. On the one hand, by modulating the cellular level of ceramides through ASAH1 (N-Acylsphingosine Amidohydrolase 1) ubiquitination, UBTD1 controls the ligand-independent phosphorylation of EGFR. On the other hand, UBTD1, via the ubiquitination of SQSTM1/p62 (Sequestosome 1) and endolysosome positioning, participates in the lysosomal degradation of EGFR. The coordination of these two ubiquitin-dependent processes contributes to the control of the duration of the EGFR signal. Moreover, we showed that UBTD1 depletion exacerbates EGFR signaling and induces cell proliferation emphasizing a hitherto unknown function of UBTD1 in EGF-driven cell proliferation.

cell biology↗

bioRxiv2020

Osh6 requires Ist2 for localization to the ER-PM contacts and efficient phosphatidylserine transport

Osh6 and Osh7 are lipid transfer proteins (LTPs) that move phosphatidylserine (PS) from the endoplasmic reticulum (ER) to the plasma membrane (PM). High PS level at the PM is key for many cellular functions. Intriguingly, Osh6/7 localize to ER-PM contact sites, although they lack membrane-targeting motifs, in contrast to multidomain LTPs that both bridge membranes and convey lipids. We show that Osh6 localization to contact sites depends on its interaction with the cytosolic tail of the ER-PM tether Ist2, a homologue of TMEM16 proteins. We identify a motif in the Ist2 tail, conserved in yeasts, as the Osh6-binding region, and we map an Ist2-binding surface on Osh6. Mutations in the Ist2 tail phenocopy osh6{Delta} osh7{Delta} deletion: they decrease cellular PS levels, and block PS transport to the PM. Our study unveils an unexpected partnership between a TMEM16-like protein and a soluble LTP, which together mediate lipid transport at contact sites.

cell biology↗