Publications by authors named "Laura Braud"

11 Publications

  • Page 1 of 1

Platelets Facilitate the Wound-Healing Capability of Mesenchymal Stem Cells by Mitochondrial Transfer and Metabolic Reprogramming.

Cell Metab 2021 02 4;33(2):283-299.e9. Epub 2021 Jan 4.

Université Paris-Est Créteil, INSERM, IMRB, 94010 Créteil, France. Electronic address:

Platelets are known to enhance the wound-healing activity of mesenchymal stem cells (MSCs). However, the mechanism by which platelets improve the therapeutic potential of MSCs has not been elucidated. Here, we provide evidence that, upon their activation, platelets transfer respiratory-competent mitochondria to MSCs primarily via dynamin-dependent clathrin-mediated endocytosis. We found that this process enhances the therapeutic efficacy of MSCs following their engraftment in several mouse models of tissue injury, including full-thickness cutaneous wound and dystrophic skeletal muscle. By combining in vitro and in vivo experiments, we demonstrate that platelet-derived mitochondria promote the pro-angiogenic activity of MSCs via their metabolic remodeling. Notably, we show that activation of the de novo fatty acid synthesis pathway is required for increased secretion of pro-angiogenic factors by platelet-preconditioned MSCs. These results reveal a new mechanism by which platelets potentiate MSC properties and underline the importance of testing platelet mitochondria quality prior to their clinical use.
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http://dx.doi.org/10.1016/j.cmet.2020.12.006DOI Listing
February 2021

Increased Sirt1 secreted from visceral white adipose tissue is associated with improved glucose tolerance in obese Nrf2-deficient mice.

Redox Biol 2021 01 24;38:101805. Epub 2020 Nov 24.

University Paris-Est Créteil, INSERM, IMRB, F-94010, Créteil, France. Electronic address:

Obesity is associated with metabolic dysregulation characterized by insulin resistance and glucose intolerance. Nuclear factor E2-related factor (Nrf2) is a critical regulator of the stress response and Nrf2-deficient mice (Nrf2) are protected against high fat diet (HFD)-induced metabolic derangement. We searched for factors that could underline this favorable phenotype and found that Nrf2 mice exhibit higher circulating levels of sirtuin 1 (Sirt1), a key player in cellular homeostasis and energy metabolism, compared to wild-type mice. Increased Sirt1 levels in Nrf2 mice were found not only in animals under standard diet but also following HFD. Interestingly, we report here that the visceral adipose tissue (eWAT) is the sole source of increased Sirt1 protein in plasma. eWAT and other fat depots displayed enhanced adipocytes lipolysis, increased fatty acid oxidation and glycolysis, suggesting autocrine and endocrine actions of Sirt1 in this model. We further demonstrate that removal of eWAT completely abolishes the increase in circulating Sirt1 and that this procedure suppresses the beneficial effect of Nrf2 deficiency on glucose tolerance, but not insulin sensitivity, following a HFD regime. Thus, in contrast to many other stressful conditions where Nrf2 deficiency exacerbates damage, our study indicates that up-regulation of Sirt1 levels specifically in the visceral adipose tissue of Nrf2 mice is a key adaptive mechanism that mitigates glucose intolerance induced by nutritional stress.
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http://dx.doi.org/10.1016/j.redox.2020.101805DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7721645PMC
January 2021

LIPE-related lipodystrophic syndrome: clinical features and disease modeling using adipose stem cells.

Eur J Endocrinol 2021 Jan;184(1):155-168

Sorbonne Université, Inserm UMRS_938, Centre de Recherche Saint Antoine, Paris, France.

Objective: The term Multiple Symmetric Lipomatosis (MSL) describes a heterogeneous group of rare monogenic disorders and multifactorial conditions, characterized by upper-body adipose masses. Biallelic variants in LIPE encoding hormone-sensitive lipase (HSL), a key lipolytic enzyme, were implicated in three families worldwide. We aimed to further delineate LIPE-related clinical features and pathophysiological determinants.

Methods: A gene panel was used to identify pathogenic variants. The disease features were reviewed at the French lipodystrophy reference center. The immunohistological, ultrastructural, and protein expression characteristics of lipomatous tissue were determined in surgical samples from one patient. The functional impact of variants was investigated by developing a model of adipose stem cells (ASCs) isolated from lipomatous tissue.

Results: We identified new biallelic LIPE null variants in three unrelated patients referred for MSL and/or partial lipodystrophy. The hallmarks of the disease, appearing in adulthood, included lower-limb lipoatrophy, upper-body and abdominal pseudo-lipomatous masses, diabetes and/or insulin resistance, hypertriglyceridemia, liver steatosis, high blood pressure, and neuromuscular manifestations. Ophthalmological investigations revealed numerous auto-fluorescent drusen-like retinal deposits in all patients. Lipomatous tissue and patient ASCs showed loss of HSL and decreased expression of adipogenic and mature adipocyte markers. LIPE-mutated ASCs displayed impaired adipocyte differentiation, decreased insulin response, defective lipolysis, and mitochondrial dysfunction.

Conslusions: Biallelic LIPE null variants result in a multisystemic disease requiring multidisciplinary care. Loss of HSL expression impairs adipocyte differentiation, consistent with the lipodystrophy/MSL phenotype and associated metabolic complications. Detailed ophthalmological examination could reveal retinal damage, further pointing to the nervous tissue as an important disease target.
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http://dx.doi.org/10.1530/EJE-20-1013DOI Listing
January 2021

Platelet-Rich Plasma Improves the Wound Healing Potential of Mesenchymal Stem Cells through Paracrine and Metabolism Alterations.

Stem Cells Int 2019 31;2019:1234263. Epub 2019 Oct 31.

Université Paris-Est, UMR-S955, UPEC, Créteil, France.

Chronic and acute nonhealing wounds represent a major public health problem, and replacement of cutaneous lesions by the newly regenerated skin is challenging. Mesenchymal stem cells (MSC) and platelet-rich plasma (PRP) were separately tested in the attempt to regenerate the lost skin. However, these treatments often remained inefficient to achieve complete wound healing. Additional studies suggested that PRP could be used in combination with MSC to improve the cell therapy efficacy for tissue repair. However, systematic studies related to the effects of PRP on MSC properties and their ability to rebuild skin barrier are lacking. We evaluated in a mouse exhibiting 4 full-thickness wounds, the skin repair ability of a treatment combining human adipose-derived MSC and human PRP by comparison to treatment with saline solution, PRP alone, or MSC alone. Wound healing in these animals was measured at day 3, day 7, and day 10. In addition, we examined in vitro and in vivo whether PRP alters in MSC their proangiogenic properties, their survival, and their proliferation. We showed that PRP improved the efficacy of engrafted MSC to replace lost skin in mice by accelerating the wound healing processes and ameliorating the elasticity of the newly regenerated skin. In addition, we found that PRP treatment stimulated , in a dose-dependent manner, the proangiogenic potential of MSC through enhanced secretion of soluble factors like VEGF and SDF-1. Moreover, PRP treatment ameliorated the survival and activated the proliferation of cultured MSC and that these effects were accompanied by an alteration of the MSC energetic metabolism including oxygen consumption rate and mitochondrial ATP production. Similar observations were found following combined administration of PRP and MSC into mouse wounds. In conclusion, our study strengthens that the use of PRP in combination with MSC might be a safe alternative to aid wound healing.
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http://dx.doi.org/10.1155/2019/1234263DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6875194PMC
October 2019

Human and murine macrophages exhibit differential metabolic responses to lipopolysaccharide - A divergent role for glycolysis.

Redox Biol 2019 04 20;22:101147. Epub 2019 Feb 20.

Institute of Transfusion Medicine, Hannover Medical School, Hannover, 30625, Germany. Electronic address:

Macrophages adopt different phenotypes in response to microenvironmental changes, which can be principally classified into inflammatory and anti-inflammatory states. Inflammatory activation of macrophages has been linked with metabolic reprogramming from oxidative phosphorylation to aerobic glycolysis. In contrast to mouse macrophages, little information is available on the link between metabolism and inflammation in human macrophages. In the current report it is demonstrated that lipopolysaccharide (LPS)-activated human peripheral blood monocyte-derived macrophages (hMDMs) fail to undergo metabolic reprogramming towards glycolysis, but rely on oxidative phosphorylation for the generation of ATP. By contrast, activation by LPS led to an increased extracellular acidification rate (glycolysis) and decreased oxygen consumption rate (oxidative phosphorylation) in mouse bone marrow-derived macrophages (mBMDMs). Mitochondrial bioenergetics after LPS stimulation in human macrophages was unchanged, but was markedly impaired in mouse macrophages. Furthermore, treatment with 2-deoxyglucose, an inhibitor of glycolysis, led to cell death in mouse, but not in human macrophages. Finally, glycolysis appeared to be critical for LPS-mediated induction of the anti-inflammatory cytokine interleukin-10 in both human and mouse macrophages. In summary, these findings indicate that LPS-induced immunometabolism in human macrophages is different to that observed in mouse macrophages.
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http://dx.doi.org/10.1016/j.redox.2019.101147DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6396203PMC
April 2019

MR (Mineralocorticoid Receptor) Induces Adipose Tissue Senescence and Mitochondrial Dysfunction Leading to Vascular Dysfunction in Obesity.

Hypertension 2019 02;73(2):458-468

From the Department of Physiology, INSERM UMRS 1138 Team 1, Centre de Recherche des Cordeliers, Sorbonne University, Paris, France (C.L., R.P.-R., N.B., F.J., A.N.D.C.).

Adipose tissue (AT) senescence and mitochondrial dysfunction are associated with obesity. Studies in obese patients and animals demonstrate that the MR (mineralocorticoid receptor) contributes to obesity-associated cardiovascular complications through its specific role in AT. However, underlying mechanisms remain unclear. This study aims to elucidate whether MR regulates mitochondrial function in obesity, resulting in AT premature aging and vascular dysfunction. Obese (db/db) and lean (db/+) mice were treated with an MR antagonist or a specific mitochondria-targeted antioxidant. Mitochondrial and vascular functions were determined by respirometry and myography, respectively. Molecular mechanisms were probed by Western immunoblotting and real-time polymerase chain reaction in visceral AT and arteries and focused on senescence markers and redox-sensitive pathways. db/db mice displayed AT senescence with activation of the p53-p21 pathway and decreased SIRT (sirtuin) levels, as well as mitochondrial dysfunction. Furthermore, the beneficial anticontractile effects of perivascular AT were lost in db/db via ROCK (Rho kinase) activation. MR blockade prevented these effects. Thus, MR activation in obesity induces mitochondrial dysfunction and AT senescence and dysfunction, which consequently increases vascular contractility. In conclusion, our study identifies novel mechanistic insights involving MR, adipose mitochondria, and vascular function that may be of importance to develop new therapeutic strategies to limit obesity-associated cardiovascular complications.
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http://dx.doi.org/10.1161/HYPERTENSIONAHA.118.11873DOI Listing
February 2019

Carbon monoxide-induced metabolic switch in adipocytes improves insulin resistance in obese mice.

JCI Insight 2018 11 15;3(22). Epub 2018 Nov 15.

Inserm U955, Team 12, Créteil, France.

Obesity is characterized by accumulation of adipose tissue and is one the most important risk factors in the development of insulin resistance. Carbon monoxide-releasing (CO-releasing) molecules (CO-RMs) have been reported to improve the metabolic profile of obese mice, but the underlying mechanism remains poorly defined. Here, we show that oral administration of CORM-401 to obese mice fed a high-fat diet (HFD) resulted in a significant reduction in body weight gain, accompanied by a marked improvement in glucose homeostasis. We further unmasked an action we believe to be novel, by which CO accumulates in visceral adipose tissue and uncouples mitochondrial respiration in adipocytes, ultimately leading to a concomitant switch toward glycolysis. This was accompanied by enhanced systemic and adipose tissue insulin sensitivity, as indicated by a lower blood glucose and increased Akt phosphorylation. Our findings indicate that the transient uncoupling activity of CO elicited by repetitive administration of CORM-401 is associated with lower weight gain and increased insulin sensitivity during HFD. Thus, prototypic compounds that release CO could be investigated for developing promising insulin-sensitizing agents.
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http://dx.doi.org/10.1172/jci.insight.123485DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6302946PMC
November 2018

Vascular endothelial function masks increased sympathetic vasopressor activity in rats with metabolic syndrome.

Am J Physiol Heart Circ Physiol 2018 03 10;314(3):H497-H507. Epub 2017 Nov 10.

Laboratoire de Pharm-Ecologie Cardiovasculaire, Avignon University , Avignon , France.

Sympathetic hyperactivation, a common feature of obesity and metabolic syndrome, is a key trigger of hypertension. However, some obese subjects with autonomic imbalance present a dissociation between sympathetic activity-mediated vasoconstriction and increased blood pressure. Here, we aimed to determine in a rat model of metabolic syndrome whether the endothelium endothelial nitric oxide (NO) synthase (eNOS)-NO pathway contributes to counteract the vasopressor effect of the sympathetic system. Rats were fed a high-fat and high-sucrose (HFS) diet for 15 wk. Sympathovagal balance was evaluated by spectral analysis of heart rate variability and plasmatic catecholamine measurements. Blood pressure was measured in the presence or absence of N-nitro-l-arginine methyl ester (l-NAME) to inhibit the contribution of eNOS. Vascular reactivity was assessed on isolated aortic rings in response to α-adrenergic agonist. The HFS diet increased sympathetic tone, which is characterized by a higher low on the high-frequency spectral power ratio and a higher plasmatic concentration of epinephrine. Despite this, no change in blood pressure was observed. Interestingly, HFS rats exhibited vascular hyporeactivity (-23.6%) to α-adrenergic receptor stimulation that was abolished by endothelial removal or eNOS inhibition (l-NAME). In addition, eNOS phosphorylation (Ser) was increased in response to phenylephrine in HFS rats only. Accordingly, eNOS inhibition in vivo revealed higher blood pressure in HFS rats compared with control rats (147 vs. 126 mmHg for mean blood pressure, respectively). Restrain of adrenergic vasopressor action by endothelium eNOS is increased in HFS rats and contributes to maintained blood pressure in the physiological range. NEW & NOTEWORTHY Despite the fact that prohypertensive sympathetic nervous system activity is markedly increased in rats with early metabolic syndrome, they present with normal blood pressure. These observations appear to be explained by increased endothelial nitric oxide synthase response to adrenergic stimulation, which results in vascular hyporeactivity to α-adrenergic stimulation, and therefore blood pressure is preserved in the physiological range. Listen to this article's corresponding podcast at http://www.physiology.org/doi/10.1152/ajpheart.00217.2017 .
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http://dx.doi.org/10.1152/ajpheart.00217.2017DOI Listing
March 2018

Antioxidant properties of tea blunt ROS-dependent lipogenesis: beneficial effect on hepatic steatosis in a high fat-high sucrose diet NAFLD obese rat model.

J Nutr Biochem 2017 02 29;40:95-104. Epub 2016 Oct 29.

Laboratoire de Pharm-Ecologie Cardiovasculaire (EA4278), Faculty of Sciences, Avignon University, 33 rue Louis Pasteur, 84000 Avignon, France.

Oxidative stress could trigger lipid accumulation in liver and thus hepatic steatosis. Tea is able to prevent liver disorders, but a direct link between antioxidant capacities and prevention of steatosis has not been reported yet. We aimed to investigate such relationship in a rat model of high fat-high sucrose diet (HFS)-induced obesity and to explore more deeply the mechanisms in isolated hepatocytes. Wistar rats were divided into a control group (standard diet), an HFS group (high fat-sucrose diet) and an HFS+tea group (HFS diet with ad-libitum access to tea drink). Body weight, fat mass, glycemic parameters in blood, lipid and oxidative stress parameters in blood and liver were measured in each group after 14 weeks. Isolated hepatocytes were treated with the reactive oxygen species (ROS) inducer t-BHP in the presence or not of antioxidants (tempol or tea), and superoxide anion production and lipid accumulation were measured using specific fluorescent probes. We reported that the HFS diet highly increased hepatic lipids content, while tea consumption attenuated steatosis and improved the oxidative status (decrease in hepatic oxidative stress, increase in plasma total antioxidant capacity). The role of antioxidant properties of tea in such phenomenon was confirmed in primary cultured rat hepatocytes. Indeed, the increase of mitochondrial ROS production with t-BHP resulted in lipid accumulation in hepatocytes (positive linear regression), and antioxidants (tempol or tea) normalized both. We reported that the antioxidant properties of tea protect rats from an obesogenic HFS diet-induced hepatic steatosis by counteracting the ROS-dependent lipogenesis.
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http://dx.doi.org/10.1016/j.jnutbio.2016.10.012DOI Listing
February 2017

Effect of Brewing Duration on the Antioxidant and Hepatoprotective Abilities of Tea Phenolic and Alkaloid Compounds in a t-BHP Oxidative Stress-Induced Rat Hepatocyte Model.

Molecules 2015 Aug 17;20(8):14985-5002. Epub 2015 Aug 17.

Laboratoire PROTEE, EB2M, Université de Toulon, CS 60 584, 83 041 Toulon Cedex, Campus La Garde, France.

Tea is an interesting source of antioxidants capable of counteracting the oxidative stress implicated in liver diseases. We investigated the impact of antioxidant molecules provided by a mixture of teas' leaves (green, oolong, pu-erh) after different infusion durations in the prevention of oxidative stress in isolated rat hepatocytes, by comparison with pure epigallocatechin-3-gallate (EGCG), the main representative of tea catechins. Dried aqueous tea extracts (ATE) obtained after 5, 15 and 30 min infusion time were characterized for total polyphenols (gallic acid equivalent), catechins, gallic acid and caffeine (HPLC-DAD/ESI-MS) contents, and for scavenging ability against 2,2-diphenyl-1-picrylhydrazyl free radical. Hepatoprotection was evaluated through hepatocyte viability tests using tert-butyl hydroperoxide as a stress inducer, (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, neutral red uptake, real-time cellular impedance) and mitochondrial function tests. We showed that a 5-min incubation time is sufficient for an optimal bioaccessibility of tea compounds with the highest antioxidative ability, which decreases for longer durations. A 4-h pretreatment of cells with ATE significantly prevented cell death by regulating reactive oxygen species production and maintaining mitochondrial integrity. Pure EGCG, at doses similar in ATE (5-12 µM), was inefficient, suggesting a plausible synergy of several water-soluble tea compounds to explain the ATE beneficial effects.
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http://dx.doi.org/10.3390/molecules200814985DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6331988PMC
August 2015