564 results on '"Prévost, G"'
Search Results
202. The 26RFa (QRFP)/GPR103 Neuropeptidergic System: A Key Regulator of Energy and Glucose Metabolism.
- Author
-
Devère M, Takhlidjt S, Prévost G, Chartrel N, Leprince J, and Picot M
- Abstract
Background: Obesity and type 2 diabetes are strongly associated pathologies, currently considered as a worldwide epidemic problem. Understanding the mechanisms that drive the development of these diseases would enable to develop new therapeutic strategies for their prevention and treatment. Particularly, the role of the brain in energy and glucose homeostasis has been studied for 2 decades. In specific, the hypothalamus contains well-identified neural networks that regulate appetite and potentially also glucose homeostasis. A new concept has thus emerged, suggesting that obesity and diabetes could be due to a dysfunction of the same, still poorly understood, neural networks., Summary: The neuropeptide 26RFa (also termed QRFP) belongs to the family of RFamide regulatory peptides and has been identified as the endogenous ligand of the human G protein-coupled receptor GPR103 (QRFPR). The primary structure of 26RFa is strongly conserved during vertebrate evolution, suggesting its crucial roles in the control of vital functions. Indeed, the 26RFa/GPR103 peptidergic system is reported to be involved in the control of various neuroendocrine functions, notably the control of energy metabolism in which it plays an important role, both centrally and peripherally, since 26RFa regulates feeding behavior, thermogenesis and lipogenesis. Moreover, 26RFa is reported to control glucose homeostasis both peripherally, where it acts as an incretin, and centrally, where the 26RFa/GPR103 system relays insulin signaling in the brain to control glucose metabolism., Key Messages: This review gives a comprehensive overview of the role of the 26RFa/GPR103 system as a key player in the control of energy and glucose metabolism. In a pathophysiological context, this neuropeptidergic system represents a prime therapeutic target whose mechanisms are highly relevant to decipher., (© 2024 S. Karger AG, Basel.)
- Published
- 2024
- Full Text
- View/download PDF
203. [Continuous glucose monitoring data: how can they be collected and used in practice?]
- Author
-
Prévost G
- Subjects
- Humans, Blood Glucose analysis, Blood Glucose Self-Monitoring, Continuous Glucose Monitoring, Diabetes Mellitus, Type 1, Hypoglycemia diagnosis, Hypoglycemia prevention & control
- Abstract
Continuous Glucose Monitoring Data: HOW CAN THEY BE COLLECTED AND USED IN PRACTICE? Continuous glucose monitoring (CGM) is becoming an essential part of diabetes management. The AGP report is obtained over a 14-day period, with at least 70% of captured data. The time spent in the 70-180 mg/dl targel range, withe a target of over 70% or 50% in frail patients, is a new parameter that is essential for assessing glycemic control via CGM. Complemented by estimated HBA1c, now called GMI (Glucose Management Indicator), the time spent in hypoglycemia (target inférieur 5% or even inférieur 1% for frail patients) and the coefficient of variation (target inférieur 36%), the CGM offers a very comprehensive analysis of blood glucose levels, with individualized treatment adjustments based on ambulatory blood glucose profiles., Competing Interests: L'auteur déclare avoir reçu des honoraires pour des interventions ponctuelles (essais cliniques, travaux scientifiques, activité de conseil, conférence ou colloque) de la part des entreprises Abbott, Amgen, AstraZeneca, Beohringer Ingelheim, Dexcom, Isis, Medtronic, Novo Nordisk, Sanofi, Eli Lilly.
- Published
- 2024
204. Glycemic Risk Index (GRI) variability in type 1 diabetes adults with HbA1c ≤ 7%: Insights for clinical evaluation and intervention.
- Author
-
Oriot P, Hermans MP, Vandelaer A, Philips JC, and Prévost G
- Subjects
- Adult, Humans, Glycated Hemoglobin, Glycemic Index, Blood Glucose, Diabetes Mellitus, Type 1
- Abstract
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
- Published
- 2024
- Full Text
- View/download PDF
205. Discordance Between Glycated Hemoglobin A1c and the Glucose Management Indicator in People With Diabetes and Chronic Kidney Disease.
- Author
-
Oriot P, Viry C, Vandelaer A, Grigioni S, Roy M, Philips JC, and Prévost G
- Subjects
- Humans, Glycated Hemoglobin, Glucose, Blood Glucose Self-Monitoring methods, Retrospective Studies, Blood Glucose, Diabetes Mellitus, Renal Insufficiency, Chronic diagnosis, Diabetes Mellitus, Type 1
- Abstract
Introduction: Assessment of glucose exposure via glycated hemoglobin A
1 c (HbA1 c) has limitations for interpretation in individuals with diabetes and chronic kidney disease (CKD). The glucose management indicator (GMI) derived from continuous glucose monitoring (CGM) data could be an alternative. However, the concordance between HbA1 c measured in laboratory and GMI (HbA1 c-GMI) is uncertain in individuals with CKD. The purpose of this study is to analyze this discrepancy., Material and Method: We performed a multicentric, retrospective, observational study. A group of individuals with diabetes and CKD (n = 170) was compared with a group of individuals with diabetes without CKD (n = 185). All individuals used an intermittently scanned continuous glucose monitoring (isCGM). A comparison of 14-day and 90-day glucose data recorded by the isCGM was performed to calculate GMI and the discordance between lab HbA1 c and GMI was analyzed by a Bland-Altman method and linear regression., Results: HbA1 c-GMI discordance was significantly higher in the CKD group versus without CKD group (0.78 ± 0.57 [0.66-0.90] vs 0.59 ± 0.44 [0.50-0.66]%, P < .005). An absolute difference >0.5% was found in 68.2% of individuals with CKD versus 42.2% of individuals without CKD. We suggest a new specific formula to estimate HbA1 c from the linear regression between HbA1 c and mean glucose CGM, namely CKD-GMI = 0.0261 × 90-day mean glucose (mg/L) + 3.5579 ( r2 = 0.59)., Conclusions: HbA1c-GMI discordance is frequent and usually in favor of an HbA1c level higher than the GMI value, which can lead to errors in changes in glucose-lowering therapy, especially for individuals with CKD. This latter population should benefit from the CGM to measure their glucose exposure more precisely., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.- Published
- 2023
- Full Text
- View/download PDF
206. [How and when to use iSGLT2 (gliflozins) in clinical practice: a consensus for clinical practice proposed by the SFD, the SFC, the CNCF and the SFNDT].
- Author
-
Diévart F, Darmon P, Halimi JM, Hadjadj S, Angoulvant D, Prévost G, Delanaye P, and Boivin JM
- Subjects
- Humans, Consensus, Sodium-Glucose Transporter 2 Inhibitors
- Published
- 2023
- Full Text
- View/download PDF
207. Interactions between the regulatory peptide 26RFa (QRFP) and insulin in the regulation of glucose homeostasis in two complementary models: The high fat 26RFa-deficient mice and the streptozotocin insulin-deficient mice.
- Author
-
Le Solliec MA, Arabo A, Takhlidjt S, Maucotel J, Devère M, Berrahmoune H, Bénani A, Nedelec E, Lefranc B, Leprince J, Picot M, Chartrel N, and Prévost G
- Subjects
- Mice, Animals, Insulin metabolism, Streptozocin, Mice, Obese, Peptides pharmacology, Obesity metabolism, Glucose metabolism, Homeostasis physiology, Diet, High-Fat, Mice, Inbred C57BL, Diabetes Mellitus, Experimental, Insulin Resistance
- Abstract
The regulatory peptide 26RFa (QRFP) is involved in the control of glucose homeostasis at the periphery by acting as an incretin, and in the brain by mediating the central antihyperglycemic effect of insulin, indicating the occurrence of a close relationship between 26RFa and insulin in the regulation of glucose metabolism. Here, we investigated the physiological interactions between 26RFa and insulin in two complementary models i.e. a model of obese/hyperglycemic mice deficient for 26RFa and a model of diabetic mice deficient for insulin. For this, transgenic 26RFa-deficient mice were made obese and chronically hyperglycemic by a 3-month high fat diet (HFD) and second group of mice was made diabetic by destruction of the β cells of the pancreatic islets using a single injection of streptozotocin. Our data reveal that 26RFa deficiency does not impact significantly the "glycemic" phenotype of the HFD mice. The pancreatic islets, liver, white adipose tissue masses are not altered by the lack of 26RFa production but the brown adipose tissue (BAT) weight is significantly increased in these animals. In diabetic insulin-deficient mice, the injection of 26RFa does not exhibit any beneficial effect on the impaired glucose homeostasis characterizing this model. Finally, we show that streptozotocin diabetic mice display lowered plasma 26RFa levels as compared to untreated mice, whereas the expression of the peptide in the duodenum is not affected. Taken together, the present results indicate that dysregulation of glucose homeostasis in obese/hyperglycemic mice is not aggravated by the absence of 26RFa that may be compensated by the increase of BAT mass. In diabetic insulin-deficient mice, the antihypergycemic effect of 26RFa is totally blunted probably as a result of the impaired insulin production characterizing this model, avoiding therefore the action of the peptide., Competing Interests: Declaration of Competing Interest The authors have no competing interests to declare., (Copyright © 2023. Published by Elsevier Ltd.)
- Published
- 2023
- Full Text
- View/download PDF
208. Editorial of the Special Issue "Toxins: Mr Hyde or Dr Jekyll?"
- Author
-
Ladant D, Prévost G, Popoff MR, and Benoit E
- Abstract
The 27th Annual Meeting of the French Society of Toxinology (SFET, http://sfet [...].
- Published
- 2023
- Full Text
- View/download PDF
209. Determination of Lipoxygenase, CYP450, and Non-Enzymatic Metabolites of Arachidonic Acid in Essential Hypertension and Type 2 Diabetes.
- Author
-
Feugray G, Pereira T, Iacob M, Moreau-Grangé L, Prévost G, Brunel V, Joannidès R, Bellien J, and Duflot T
- Abstract
Type 2 diabetes (T2D) and hypertension (HTN) are common risk factors of cardiovascular diseases (CVD) characterized by chronic low-grade systemic inflammation and impaired endothelial function. This study aimed to assess whether levels of non-enzymatic, lipoxygenase (LOX)- and cytochrome P450 (CYP)-derived arachidonic acid (ARA) metabolites, which are known regulators of vascular homeostasis, are affected by HTN and T2D. For this objective, 17 plasma level derivatives of ARA were quantitated by chromatography coupled with mass spectrometry in 44 patients (12 healthy, 8 HTN, 7 T2D, and 17 HTN + T2D). Effects of hyperglycemic and hyperinsulinemic clamps on ARA metabolite levels were assessed in seven healthy subjects. No significant differences in the plasma levels of ARA metabolites were observed for T2D patients compared with healthy volunteers. HTN was associated with an alteration of ARA metabolite correlation patterns with increased 20-, 19-, 15-, and 8-hydroxyeicosatrienoic acid (HETE). A decrease of 20-HETE was also observed during both hyperglycemic and hyperinsulinemic clamps. Additional experiments are needed to assess whether the modulation of HETE metabolites in HTN may be of interest. Furthermore, although not affected by T2D, it remains to investigate whether the decrease of 20-HETE observed during clamps may be related to the regulation of glucose tolerance and insulin signaling.
- Published
- 2022
- Full Text
- View/download PDF
210. The 26RFa (QRFP)/GPR103 neuropeptidergic system in mice relays insulin signalling into the brain to regulate glucose homeostasis.
- Author
-
El Mehdi M, Takhlidjt S, Devère M, Arabo A, Le Solliec MA, Maucotel J, Bénani A, Nedelec E, Duparc C, Lefranc B, Leprince J, Anouar Y, Prévost G, Chartrel N, and Picot M
- Subjects
- Animals, Homeostasis drug effects, Male, Mice, Brain drug effects, Brain metabolism, Glucose metabolism, Insulin metabolism, Neuropeptides metabolism, Neuropeptides pharmacology, Receptor, Insulin metabolism
- Abstract
Aims/hypothesis: 26RFa (pyroglutamilated RFamide peptide [QRFP]) is a biologically active peptide that regulates glucose homeostasis by acting as an incretin and by increasing insulin sensitivity at the periphery. 26RFa is also produced by a neuronal population localised in the hypothalamus. In this study we investigated whether 26RFa neurons are involved in the hypothalamic regulation of glucose homeostasis., Methods: 26Rfa
+/+ , 26Rfa-/- and insulin-deficient male C57Bl/6J mice were used in this study. Mice received an acute intracerebroventricular (i.c.v.) injection of 26RFa, insulin or the 26RFa receptor (GPR103) antagonist 25e and were subjected to IPGTTs, insulin tolerance tests, acute glucose-stimulated insulin secretion tests and pyruvate tolerance tests (PTTs). Secretion of 26RFa by hypothalamic explants after incubation with glucose, leptin or insulin was assessed. Expression and quantification of the genes encoding 26RFa, agouti-related protein, the insulin receptor and GPR103 were evaluated by quantitative reverse transcription PCR and RNAscope in situ hybridisation., Results: Our data indicate that i.c.v.-injected 26RFa induces a robust antihyperglycaemic effect associated with an increase in insulin production by the pancreatic islets. In addition, we found that insulin strongly stimulates 26Rfa expression and secretion by the hypothalamus. RNAscope experiments revealed that neurons expressing 26Rfa are mainly localised in the lateral hypothalamic area, that they co-express the gene encoding the insulin receptor and that insulin induces the expression of 26Rfa in these neurons. Concurrently, the central antihyperglycaemic effect of insulin is abolished in the presence of a GPR103 antagonist and in 26RFa-deficient mice. Finally, our data indicate that the hypothalamic 26RFa neurons are not involved in the central inhibitory effect of insulin on hepatic glucose production, but mediate the central effects of the hormone on its own peripheral production., Conclusion/interpretation: We have identified a novel mechanism in the hypothalamic regulation of glucose homeostasis, the 26RFa/GPR103 system, and we provide evidence that this neuronal peptidergic system is a key relay for the central regulation of glucose metabolism by insulin., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)- Published
- 2022
- Full Text
- View/download PDF
211. Aproximación al concepto de globalización y de los derechos humanos en la obra de Niklas Luhmann
- Author
-
Oliván, Fernando, director, Sosoe, Lukas K., Guibentif, Pierre, Prévost, Gérard, Ojeda, Luis, Doncel, Luis V., Gomariz, Tomás P., Kaipl, Esteban, Dahiri, Mohammed, Oliván, Fernando, Sosoe, Lukas K., Guibentif, Pierre, Prévost, Gérard, Ojeda, Luis, Doncel, Luis V., Gomariz, Tomás P., Kaipl, Esteban, and Dahiri, Mohammed
- Published
- 2017
- Full Text
- View/download PDF
212. The switch from rapid-acting to concentrated regular insulin improves glucose control in type 2 diabetes patients on pump therapy: A cohort survey.
- Author
-
Deberles E, Morello R, Hardouin J, Amadou C, Benhamou PY, Prévost G, Schaepelynck P, Chaillous L, Joubert M, and Reznik Y
- Subjects
- Blood Glucose, Blood Glucose Self-Monitoring, Drug Substitution, Glycated Hemoglobin analysis, Humans, Hypoglycemic Agents administration & dosage, Hypoglycemic Agents therapeutic use, Insulin Infusion Systems, Retrospective Studies, Diabetes Mellitus, Type 2 drug therapy, Hypoglycemia drug therapy, Hypoglycemia prevention & control, Insulin administration & dosage, Insulin therapeutic use
- Abstract
Background: To evaluate the impact of switching from U-100 to U-500 insulin in patients with type 2 diabetes mellitus (T2DM) uncontrolled with continuous subcutaneous insulin infusion (CSII) by pump., Methods: We retrospectively collected data from patients with T2DM, treated by U-100 CSII, who were switched to U-500 regular insulin where haemoglobin A1c (Hb
A1c ) was >8% and/or insulin total daily dose (TDD) was >100 UI/d. Data collection from patient medical records included HbA1c , lipid levels, liver biomarkers, weight, TDD, declared hypoglycaemic episodes and measured by continuous glucose monitoring (CGM)., Results: Sixty-five patients were included, aged 63.9 ± 8.6 years, insulin pump since 3.7 ± 3 years, TDD 186 ± 52 U/day, body mass index 39.4 ± 5.3 kg/m², HbA1c 9.03 ± 1.6%. After switching to U-500 insulin, HbA1c dropped by -0.96% (P < 0.0001) at one year with the effect maintained at three years (- 0.95%, P < 0.01). A subgroup analysis (n=42/65) using a severity score which covered the three previous years on U-100 and the next three years on U-500 insulin confirmed the latter's efficacy. Body weight increased by + 4.8 kg and TDD by 16% at three years. Declared non-severe hypoglycaemia increased significantly three- to four-fold during follow up, but % time-below-range at six months did not differ between the two treatments. Baseline HbA1c correlated with improved glucose control with U-500., Conclusions: U-100 to U-500 insulin switch improves glucose control in CSII T2DM patients, especially with high baseline HbA1c . Use of concentrated insulin in pumps may represent an advance in the strategy for treating T2DM insulin resistant states with uncontrolled hyperglycaemia after a switch from multiple daily injections to pump therapy., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)- Published
- 2022
- Full Text
- View/download PDF
213. Report from the 27th (Virtual) Meeting on Toxinology, "Toxins: Mr Hyde or Dr Jekyll?", Organized by the French Society of Toxinology, 9-10 December 2021.
- Author
-
Ladant D, Marchot P, Diochot S, Prévost G, Popoff MR, and Benoit E
- Subjects
- Animals, Awards and Prizes, Humans, Societies, Scientific, Toxins, Biological pharmacology, Toxins, Biological therapeutic use, Toxins, Biological toxicity
- Abstract
The French Society of Toxinology (SFET) organized its 27th annual meeting on 9-10 December 2021 as a virtual meeting (e-RT27). The central theme of this meeting was "Toxins: Mr Hyde or Dr Jekyll?", emphasizing the latest findings on plant, fungal, algal, animal and bacterial toxins during 10 lectures, 15 oral communications (shorter lectures) and 20 posters shared by ca. 80 participants. The abstracts of lectures and posters, as well as the winners of the best oral communication and poster awards, are presented in this report.
- Published
- 2022
- Full Text
- View/download PDF
214. Acute but Not Chronic Central Administration of the Neuropeptide 26RFa (QRFP) Improves Glucose Homeostasis in Obese/Diabetic Mice.
- Author
-
Le Solliec MA, Arabo A, Takhlidjt S, Maucotel J, Devère M, Riancho J, Berrahmoune H, do Rego JL, do Rego JC, Bénani A, Nedelec E, Lefranc B, Leprince J, Anouar Y, Picot M, Chartrel N, and Prévost G
- Subjects
- Animals, Mice, Mice, Obese, Homeostasis, Peptides pharmacology, Glucose metabolism, Obesity metabolism, RNA, Messenger, Hypoglycemic Agents pharmacology, Diabetes Mellitus, Experimental, Neuropeptides metabolism, Insulins pharmacology
- Abstract
Introduction: The aim of the study is to investigate whether acute or chronic central administration of the hypothalamic neuropeptide 26RFa may ameliorate the glycemic control of obese/diabetic mice., Methods: Mice were treated for 4 months with a high-fat (HF) diet and received a single i.c.v. injection of 26RFa (3 µg) or a chronic i.c.v. administration of the peptide during 28 days via osmotic minipumps (25 µg/day). i.p. and oral glucose (GLU) tolerance tests, insulin (INS) tolerance test, glucose-stimulated insulin secretion (GSIS), food/water intake, horizontal/vertical activity, energy expenditure, meal pattern, and whole-body composition were monitored. In addition, 26RFa and GPR103 mRNA expressions as well as plasma 26RFa levels were evaluated by RT-QPCR and radioimmunoassay., Results: Acute administration of 26RFa in HF mice induced a robust antihyperglycemic effect by enhancing INS secretion, whereas chronic administration of the neuropeptide is unable to improve glucose homeostasis in these obese/diabetogenic conditions. By contrast, chronic 26RFa treatment induced an increase of the body weight accompanied with an enhanced food intake and a decreased energy expenditure. Finally, we show that the HF diet does not alter the hypothalamic expression of the 26RFa/GPR103 neuropeptidergic system nor the levels of circulating 26RFa., Conclusion: Our data indicate that the central beneficial effect of 26RFa on glucose homeostasis, by potentiating GSIS, is preserved in HF mice. However, chronic administration of the neuropeptide is unable to balance glycemia in these pathophysiological conditions, suggesting that the hypothalamic 26RFa/GPR103 neuropeptidergic system mainly affects short-term regulation of glucose metabolism., (© 2022 S. Karger AG, Basel.)
- Published
- 2022
- Full Text
- View/download PDF
215. Chronic Madura foot in a patient with Charcot foot.
- Author
-
Tedbirt B, Thorin-Savouré A, Prévost G, and Carvalho P
- Subjects
- Foot, Humans, Lower Extremity, Arthropathy, Neurogenic, Diabetic Foot complications, Diabetic Foot diagnosis, Mycetoma
- Published
- 2021
- Full Text
- View/download PDF
216. Race in Cuba : Essays on the Revolution and Racial Inequality
- Author
-
DOMÍNGUEZ, ESTEBAN MORALES, Prevost, Gary, Nimtz, August, DOMÍNGUEZ, ESTEBAN MORALES, Prevost, Gary, and Nimtz, August
- Published
- 2012
217. Point-Substitution of Phenylalanine Residues of 26RFa Neuropeptide: A Structure-Activity Relationship Study.
- Author
-
Lefranc B, Alim K, Neveu C, Le Marec O, Dubessy C, Boutin JA, Chuquet J, Vaudry D, Prévost G, Picot M, Vaudry H, Chartrel N, and Leprince J
- Subjects
- Animals, CHO Cells, Cricetulus, Humans, Phenylalanine chemistry, Phenylalanine genetics, Receptors, G-Protein-Coupled metabolism, Structure-Activity Relationship, Amino Acid Substitution, Neuropeptides chemistry, Neuropeptides genetics, Neuropeptides pharmacology, Receptors, G-Protein-Coupled agonists
- Abstract
26RFa is a neuropeptide that activates the rhodopsin-like G protein-coupled receptor QRFPR/GPR103. This peptidergic system is involved in the regulation of a wide array of physiological processes including feeding behavior and glucose homeostasis. Herein, the pharmacological profile of a homogenous library of QRFPR-targeting peptide derivatives was investigated in vitro on human QRFPR-transfected cells with the aim to provide possible insights into the structural determinants of the Phe residues to govern receptor activation. Our work advocates to include in next generations of 26RFa
(20-26) -based QRFPR agonists effective substitutions for each Phe unit, i.e., replacement of the Phe22 residue by a constrained 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid moiety, and substitution of both Phe24 and Phe26 by their para -chloro counterpart. Taken as a whole, this study emphasizes that optimized modifications in the C-terminal part of 26RFa are mandatory to design selective and potent peptide agonists for human QRFPR.- Published
- 2021
- Full Text
- View/download PDF
218. The impact of diabetes on heart failure development: The cardio-renal-metabolic connection.
- Author
-
Valensi P, Prévost G, Pinto S, Halimi JM, and Donal E
- Subjects
- Diabetes Mellitus, Type 2 pathology, Heart Failure physiopathology, Humans, Renal Insufficiency, Chronic pathology, Diabetes Mellitus, Type 2 complications, Heart Failure etiology, Renal Insufficiency, Chronic complications
- Abstract
Heart failure (HF) and chronic kidney disease (CKD) are often associated in type 2 diabetes (T2D), aggravate each other and exert synergistic effects to increase the risk of cardiac and renal events. The risks of renal worsening in HF patients and HF in CKD patients need to be evaluated to tailor preventive therapy. The recent CV and renal trials enriched our knowledge about the natural history of HF and CKD in T2D and provided evidence for the benefit of sodium-glucose cotransporter 2 inhibitors (SGLT2is) in HF and renal decline prevention. SGLT-2is are the best choice in patients with HFrEF to improve CV prognosis and HF-related outcomes and also to prevent kidney-related outcomes, and in CKD patients to slow down renal failure and also reduce hospitalization for HF and CV death. In both situations the number of patients to treat in order to prevent such events in one patient is lower than in the general T2D population at high CV risk. GLP1-receptor agonists could be an alternative in a patient who is intolerant or has a contraindication to SGLT-2is. A tight collaboration between diabetologists, nephrologists and cardiologists should be encouraged for a holistic and effective strategy to reduce the burden of cardio-renal-metabolic interaction., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: PV discloses the following potential conflicts of interest: lectures for Abbott, AstraZeneca, Bayer, Eli Lilly, Hikma Pharmaceuticals, Merck Sharp & Dohme, Novo Nordisk, Novartis, Pfizer, Sanofi; research grants from Abbott, Bristol-Myers-Squibb–AstraZeneca, Novo Nordisk; participation in expert committees for AstraZeneca, Boehringer Ingelheim, Novo Nordisk, Daiichi Sankyo, Sanofi, Servier, Stendo. GP discloses the potential following conflicts of interest: lectures for Abbott, AstraZeneca, Eli-Lilly, Merck-Sharp-Dohme, Novo Nordisk, Sanofi; participation to Expert Committees for Merck-Sharp-Dohme, Novo Nordisk, Sanofi. SP discloses no conflict of interest. JMH discloses the following potential conflicts of interest: consulting fees from Astra Zeneca, Alexion, Servier, Vifor Fresenius, Merck-Sharp-Dohme, Novo Nordisk, Boehringer Ingelheim France, Sanofi, Bayer. ED discloses the following potential conflicts of interest: consulting fees from AstraZeneca, General Electric Healthcare, Bristol-Myers-Squibb., (Copyright © 2021. Published by Elsevier B.V.)
- Published
- 2021
- Full Text
- View/download PDF
219. Rare Forms of Lipomatosis: Dercum's Disease and Roch-Leri Mesosomatous Lipomatosis.
- Author
-
Lemaitre M, Aubert S, Chevalier B, Jannin A, Bourry J, Prévost G, Lefebvre H, and Vantyghem MC
- Abstract
In contrast to obesity, which is very frequent, lipomatosis and lipodystrophy syndromes are rare diseases of adipose tissue. Lipodystrophy syndromes are characterized by metabolic abnormalities associated with partial or generalized lipoatrophy. Lipomatosis is defined by the presence of several body lipomas without lipoatrophy. Dercum's disease (DD) and Roch-Leri mesosomatous lipomatosis (RLML) are rare and poorly characterized forms of lipomatosis. They have raised little clinical interest despite the non-negligible consequences of DD on quality of life. The main clinical presentation of these diseases includes multiple lipomas, which are painful in DD (in contrast to RLML). The two diseases are frequently associated with obesity and metabolic syndrome, with hypertension, diabetes, or dyslipidemia. The long-term course of the diseases remains poorly described. DD affects mainly women, whereas RLML mostly affects men. In both diseases lipomas are found on the back and thighs, as well as on the abdomen in DD and the forearms in RLML. The painful lipomas tend to recur after surgery in DD (in contrast to RLML). Most cases are sporadic. No specific treatment has been identified, as the pathophysiology remains unknown. Nevertheless, low-grade fat inflammation and specific abnormalities such as hyperbasophilia deserve further investigation. The aim of this review is to analyze the available literature on the topic.
- Published
- 2021
- Full Text
- View/download PDF
220. Staphylococcus aureus Panton-Valentine Leukocidin triggers an alternative NETosis process targeting mitochondria.
- Author
-
Mazzoleni V, Zimmermann K, Smirnova A, Tarassov I, and Prévost G
- Subjects
- Adult, Cells, Cultured, Female, Healthy Volunteers, Hemolysin Proteins metabolism, Humans, Male, NADPH Oxidases metabolism, Reactive Oxygen Species metabolism, Respiratory Burst, Staphylococcal Infections microbiology, Bacterial Proteins metabolism, Bacterial Toxins metabolism, Exotoxins metabolism, Extracellular Traps immunology, Leukocidins metabolism, Mitochondria metabolism, Neutrophils immunology, Staphylococcal Infections immunology, Staphylococcus aureus metabolism
- Abstract
Panton-Valentine Leukocidin (PVL) is a bicomponent leukotoxin produced by 3%-10% of clinical Staphylococcus aureus (SA) strains involved in the severity of hospital and community-acquired infections. Although PVL was long known as a pore-forming toxin, recent studies have challenged the formation of a pore at the plasma membrane, while its endocytosis and the exact mode of action remain to be defined. In vitro immunolabeling of human neutrophils shows that Neutrophil Extracellular Traps (NETosis) is triggered by the action of purified PVL, but not by Gamma hemolysin CB (HlgCB), a structurally similar SA leukotoxin. PVL causes the ejection of chromatin fibers (NETs) decorated with antibacterial peptides independently of the NADPH oxidase oxidative burst. Leukotoxin partially colocalizes with mitochondria and enhances the production of reactive oxygen species from these organelles, while showing an increased autophagy, which results unnecessary for NETs ejection. PVL NETosis is elicited through Ca
2+ -activated SK channels and Myeloperoxidase activity but is abolished by Allopurinol pretreatment of neutrophils. Moreover, massive citrullination of the histone H3 is performed by peptidyl arginine deiminases. Inhibition of this latter enzymes fails to abolish NET extrusion. Unexpectedly, PVL NETosis does not seem to involve Src kinases, which is the main kinase family activated downstream the binding of PVL F subunit to CD45 receptor, while the specific kinase pathway differs from the NADPH oxidase-dependent NETosis. PVL alone causes a different and specific form of NETosis that may rather represent a bacterial strategy conceived to disarm and disrupt the immune response, eventually allowing SA to spread., (© 2020 The Authors. The FASEB Journal published by Wiley Periodicals LLC on behalf of Federation of American Societies for Experimental Biology.)- Published
- 2021
- Full Text
- View/download PDF
221. Panton-Valentine Leucocidin of Staphylococcus aureus Induces Oxidative Stress and Neurotransmitter Imbalance in a Retinal Explant Model.
- Author
-
Wurtz M, Ruhland E, Liu X, Namer IJ, Mazzoleni V, Lipsker D, Keller D, Prévost G, and Gaucher D
- Subjects
- Acetylcholine metabolism, Animals, Cells, Cultured, Culture Media, Cytokines metabolism, Fluorescent Dyes, Glycine metabolism, Magnetic Resonance Spectroscopy, Microscopy, Fluorescence, Mitochondria drug effects, Mitochondria metabolism, NADP metabolism, Rabbits, Real-Time Polymerase Chain Reaction, Retinal Ganglion Cells metabolism, Xanthine Oxidase metabolism, gamma-Aminobutyric Acid metabolism, Bacterial Toxins pharmacology, Exotoxins pharmacology, Leukocidins pharmacology, Oxidative Stress drug effects, Reactive Oxygen Species metabolism, Receptor, Anaphylatoxin C5a metabolism, Retinal Ganglion Cells drug effects, Staphylococcus aureus chemistry
- Abstract
Purpose: Endophthalmitis models have reported the virulent role of Panton-Valentine leucocidin (PVL) secreted by Staphylococcus aureus on the retina. PVL targets retinal ganglion cells (RGCs), expressing PVL membrane receptor C5aR. Interactions between PVL and retinal cells lead to glial activation, retinal inflammation, and apoptosis. In this study, we explored oxidative stress and retinal neurotransmitters in a rabbit retinal explant model incubated with PVL., Methods: Reactive oxygen species (ROS) production in RGCs has been assessed with fluorescent probes and immunohistochemistry. Nuclear magnetic resonance (NMR) spectroscopy quantified retinal concentrations of antioxidant molecules and neurotransmitters, and concentrations of neurotransmitters released in the culture medium. Quantifying the expression of some pro-inflammatory and anti-inflammatory factors was performed using RT-qPCR., Results: PVL induced a mitochondrial ROS production in RGCs after four hours' incubation with the toxin. Enzymatic sources of ROS, involving nicotinamide adenine dinucleotide phosphate-oxidase and xanthine oxidase, were also activated after four hours in PVL-treated retinal explants. Retinal antioxidants defenses, that is, glutathione, ascorbate and taurine, decreased after two hours' incubation with PVL. Glutamate retinal concentrations and glutamate release in the culture medium remained unaltered in PVL-treated retinas. GABA, glycine, and acetylcholine (Ach) retinal concentrations decreased after PVL treatment. Glycine release in the culture medium decreased, whereas Ach release increased after PVL treatment. Expression of proinflammatory and anti-inflammatory cytokines remained unchanged in PVL-treated explants., Conclusions: PVL activates oxidative pathways and alters neurotransmitter retinal concentrations and release, supporting the hypothesis that PVL could induce a neurogenic inflammation in the retina.
- Published
- 2021
- Full Text
- View/download PDF
222. Clinical Biofilm Ring Test ® Reveals the Potential Role of β-Lactams in the Induction of Biofilm Formation by P. aeruginosa in Cystic Fibrosis Patients.
- Author
-
Olivares E, Tasse J, Badel-Berchoux S, Provot C, Prévost G, and Bernardi T
- Abstract
Biofilms are characterized by high tolerance to antimicrobials. However, conventional antibiograms are performed on planktonic microorganisms. Through the clinical Biofilm Ring Test
® (cBRT), initially aimed to measure the adhesion propensity of bacteria, we discerned a variable distribution of biofilm-producer strains among P. aeruginosa samples isolated from expectorations of cystic fibrosis (CF) patients. Despite a majority of spontaneous adherent isolates, few strains remained planktonic after 5 h of incubation. Their analysis by an adapted protocol of the cBRT revealed an induction of the biofilm early formation by sub-inhibitory doses of β-lactams. Microscopic observations of bacterial cultures stained with Syto 9/Propidium Iodide (PI) confirmed the ability of antimicrobials to increase either the bacterial biomass or the biovolume occupied by induced sessile cells. Finally, the cBRT and its derivatives enabled to highlight in a few hours the potential inducer property of antibiotics on bacterial adhesion. This phenomenon should be considered carefully in the context of CF since patients are constantly under fluctuating antimicrobial treatments. To conclude, assays derived from the Biofilm Ring Test® (BRT) device, not only define efficient doses preventing biofilm formation, but could be useful for the antimicrobial selection in CF, to avoid inducer molecules of the early biofilm initiation.- Published
- 2020
- Full Text
- View/download PDF
223. Glucose homeostasis is impaired in mice deficient in the neuropeptide 26RFa (QRFP).
- Author
-
El-Mehdi M, Takhlidjt S, Khiar F, Prévost G, do Rego JL, do Rego JC, Benani A, Nedelec E, Godefroy D, Arabo A, Lefranc B, Leprince J, Anouar Y, Chartrel N, and Picot M
- Subjects
- Animals, Energy Metabolism genetics, Feeding Behavior, Gene Knockout Techniques, Hyperglycemia genetics, Hyperglycemia metabolism, Insulin biosynthesis, Insulin-Secreting Cells metabolism, Locomotion genetics, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Phenotype, Blood Glucose metabolism, Homeostasis genetics, Neuropeptides deficiency, Neuropeptides genetics
- Abstract
Introduction: 26RFa (pyroglutamyl RFamide peptide (QRFP)) is a biologically active peptide that has been found to control feeding behavior by stimulating food intake, and to regulate glucose homeostasis by acting as an incretin. The aim of the present study was thus to investigate the impact of 26RFa gene knockout on the regulation of energy and glucose metabolism., Research Design and Methods: 26RFa mutant mice were generated by homologous recombination, in which the entire coding region of prepro26RFa was replaced by the iCre sequence. Energy and glucose metabolism was evaluated through measurement of complementary parameters. Morphological and physiological alterations of the pancreatic islets were also investigated., Results: Our data do not reveal significant alteration of energy metabolism in the 26RFa-deficient mice except the occurrence of an increased basal metabolic rate. By contrast, 26RFa mutant mice exhibited an altered glycemic phenotype with an increased hyperglycemia after a glucose challenge associated with an impaired insulin production, and an elevated hepatic glucose production. Two-dimensional and three-dimensional immunohistochemical experiments indicate that the insulin content of pancreatic β cells is much lower in the 26RFa
-/- mice as compared with the wild-type littermates., Conclusion: Disruption of the 26RFa gene induces substantial alteration in the regulation of glucose homeostasis, with in particular a deficit in insulin production by the pancreatic islets. These findings further support the notion that 26RFa is an important regulator of glucose homeostasis., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)- Published
- 2020
- Full Text
- View/download PDF
224. Clinical Impact of Antibiotics for the Treatment of Pseudomonas aeruginosa Biofilm Infections.
- Author
-
Olivares E, Badel-Berchoux S, Provot C, Prévost G, Bernardi T, and Jehl F
- Abstract
Bacterial biofilms are highly recalcitrant to antibiotic therapies due to multiple tolerance mechanisms. The involvement of Pseudomonas aeruginosa in a wide range of biofilm-related infections often leads to treatment failures. Indeed, few current antimicrobial molecules are still effective on tolerant sessile cells. In contrast, studies increasingly showed that conventional antibiotics can, at low concentrations, induce a phenotype change in bacteria and consequently, the biofilm formation. Understanding the clinical effects of antimicrobials on biofilm establishment is essential to avoid the use of inappropriate treatments in the case of biofilm infections. This article reviews the current knowledge about bacterial growth within a biofilm and the preventive or inducer impact of standard antimicrobials on its formation by P. aeruginosa . The effect of antibiotics used to treat biofilms of other bacterial species, as Staphylococcus aureus or Escherichia coli , was also briefly mentioned. Finally, it describes two in vitro devices which could potentially be used as antibiotic susceptibility testing for adherent bacteria., (Copyright © 2020 Olivares, Badel-Berchoux, Provot, Prévost, Bernardi and Jehl.)
- Published
- 2020
- Full Text
- View/download PDF
225. CVOTs: What did the endocrinologist learn?
- Author
-
Valensi P and Prévost G
- Subjects
- Humans, Hypoglycemic Agents pharmacology, Diabetes Mellitus, Type 2 drug therapy, Endocrinologists standards, Hypoglycemic Agents therapeutic use
- Abstract
The recent CVOTs which tested the new glucose-lowering drugs (GLD) show that in patients with type 2 diabetes mellitus (T2DM) it is now possible to reduce cardiovascular complications including ischemic events and hospitalization for heart failure, and mortality, and, to some extent, microvascular complications of diabetes, in particular renal outcomes. Additionally CVOTs provide major informations on safety and metabolic effects for long-term use of these drugs. The benefits with GLP-1 RAs are most likely derived through the reduction of atherosclerosis-related events while SGLT-2is seem mostly to reduce heart failure-related events. Specific mechanisms independent from glucose control are involved. Based on CVOTs results it is time, as stated in the new EASD-ADA and ESC/EASD guidelines, to take into consideration such opportunities in the decision-making process when treating T2DM patients, favoring the use of drugs that have shown clear cardiovascular and renal benefits. The treatment decisions require more expertise in the evaluation of cardiovascular and renal risk which becomes a major determinant for the choice of GLD treatment, the target for lipids, the adjustment of anti-hypertensive treatments and the prescription of aspirin. In this context it is essential that endocrinologists-diabetologists communicate more with cardiologists and nephrologists and with the primary care practitioners., Competing Interests: Declaration of Competing Interest Paul Valensi disclosed the potential following conflict of interest: - lectures for Abbott, AstraZeneca, Bayer, Eli-Lilly, Hikma, Merck-Sharp-Dohme, Novo Nordisk, Novartis, Pfizer, Sanofi; - research grants from Abbott, Bristol-Myers-Squibb-AstraZeneca, Novo Nordisk; participation to Expert Committees for Astra Zeneca, Boehringer Ingelheim, Novo Nordisk, Daiichi-Sankyo, Sanofi. Gaëtan Prévost disclosed the potential following conflict of interest: - lectures for Abbott, AstraZeneca, Eli-Lilly, Merck-Sharp-Dohme, Novo Nordisk, Sanofi; participation to Expert Committees for Merck-Sharp-Dohme, Novo Nordisk, Sanofi., (Copyright © 2019 Elsevier B.V. All rights reserved.)
- Published
- 2020
- Full Text
- View/download PDF
226. Targets for blood glucose: What have the trials told us.
- Author
-
Valensi P, Prévost G, Schnell O, Standl E, and Ceriello A
- Subjects
- Diabetic Angiopathies prevention & control, Glycated Hemoglobin analysis, Humans, Life Style, Quality of Life, Randomized Controlled Trials as Topic, Blood Glucose analysis, Cardiovascular Diseases prevention & control, Diabetes Mellitus, Type 2 prevention & control
- Abstract
The challenges of diabetes treatment are to prevent or delay microangiopathic complications and macrovascular disease. Early, effective and sustained glycaemic control is advocated by all diabetes guidelines to mitigate the risks of prolonged hyperglycaemia. The post-hoc analyses of the large randomised glucose intervention trials and the long-term results of these trials have shown clearly that intensive glycaemic control may have more favourable cardiovascular effects when initiated earlier in the course of diabetes, particularly among in patients without cardiovascular disease. Based on the intervention trials a haemoglobin A1c level of less than 7.0% (<53 mmol/mol) is a generally accepted target to reduce microvascular disease and should be initiated early in the course of the diabetes. However, haemoglobin A1c targets should be individualised. Achieving a good glycaemic control without detrimental effect and preferably with benefit to the cardiovascular system and to renal function is an important challenge. When targeting a tight glycaemic control, avoidance of hypoglycaemia is crucial particularly in patients with coronary artery disease and in patients with heart failure. The cardiovascular outcomes trials performed to test the cardiovascular safety of the new glucose-lowering therapies offer compelling evidence in favour of the role of these drugs for cardiovascular prevention. Thus, both the glycaemic target and the choice of therapies should now be defined on an individual basis.
- Published
- 2019
- Full Text
- View/download PDF
227. Neuropeptide 26RFa (QRFP) is a key regulator of glucose homeostasis and its activity is markedly altered in obese/hyperglycemic mice.
- Author
-
Prévost G, Arabo A, Le Solliec MA, Bons J, Picot M, Maucotel J, Berrahmoune H, El Mehdi M, Cherifi S, Benani A, Nédélec E, Coëffier M, Leprince J, Nordqvist A, Brunel V, Déchelotte P, Lefebvre H, Anouar Y, and Chartrel N
- Subjects
- Animals, Blood Glucose drug effects, Blood Glucose metabolism, Cells, Cultured, Glucose Tolerance Test, Homeostasis drug effects, Humans, Hyperglycemia complications, Insulin metabolism, Male, Mice, Mice, Inbred C57BL, Mice, Obese, Neuropeptides physiology, Obesity complications, Carbohydrate Metabolism drug effects, Glucose metabolism, Hyperglycemia metabolism, Neuropeptides pharmacology, Obesity metabolism
- Abstract
Recent studies have shown that the hypothalamic neuropeptide 26RFa regulates glucose homeostasis by acting as an incretin and increasing insulin sensitivity. In this study, we further characterized the role of the 26RFa/GPR103 peptidergic system in the global regulation of glucose homeostasis using a 26RFa receptor antagonist and also assessed whether a dysfunction of the 26RFa/GPR103 system occurs in obese hyperglycemic mice. First, we demonstrate that administration of the GPR103 antagonist reduces the global glucose-induced incretin effect and insulin sensitivity whereas, conversely, administration of exogenous 26RFa attenuates glucose-induced hyperglycemia. Using a mouse model of high-fat diet-induced obesity and hyperglycemia, we found a loss of the antihyperglcemic effect and insulinotropic activity of 26RFa, accompanied with a marked reduction of its insulin-sensitive effect. Interestingly, this resistance to 26RFa is associated with a downregulation of the 26RFa receptor in the pancreatic islets, and insulin target tissues. Finally, we observed that the production and release kinetics of 26RFa after an oral glucose challenge is profoundly altered in the high-fat mice. Altogether, the present findings support the view that 26RFa is a key regulator of glucose homeostasis whose activity is markedly altered under obese/hyperglycemic conditions.
- Published
- 2019
- Full Text
- View/download PDF
228. The neuropeptide 26RFa in the human gut and pancreas: potential involvement in glucose homeostasis.
- Author
-
Prévost G, Picot M, Le Solliec MA, Arabo A, Berrahmoune H, El Mehdi M, Cherifi S, Benani A, Nédélec E, Gobet F, Brunel V, Leprince J, Lefebvre H, Anouar Y, and Chartrel N
- Abstract
Objective: Recent studies performed in mice revealed that the neuropeptide 26RFa regulates glucose homeostasis by acting as an incretin and by increasing insulin sensitivity. However, in humans, an association between 26RFa and the regulation of glucose homeostasis is poorly documented. In this study, we have thus investigated in detail the distribution of 26RFa and its receptor, GPR103, in the gut and the pancreas, and determined the response of this peptidergic system to an oral glucose challenge in obese patients., Design and Methods: Distribution of 26RFa and GPR103 was examined by immunohistochemistry using gut and pancreas tissue sections. Circulating 26RFa was determined using a specific radioimmunoassay in plasma samples collected during an oral glucose tolerance test., Results: 26RFa and GPR103 are present all along the gut but are more abundant in the stomach and duodenum. In the stomach, the peptide and its receptor are highly expressed in the gastric glands, whereas in the duodenum, ileum and colon they are present in the enterocytes and the goblet cells. In the pancreatic islets, the 26RFa/GPR103 system is mostly present in the β cells. During an oral glucose tolerance test, plasma 26RFa profile is different between obese patients and healthy volunteers, and we found strong positive correlations between 26RFa blood levels and the BMI, and with various parameters of insulin secretion and insulin resistance., Conclusion: The present data suggest an involvement of the 26RFa/GPR103 peptidergic system in the control of human glucose homeostasis.
- Published
- 2019
- Full Text
- View/download PDF
229. fbl -Typing of Staphylococcus lugdunensis : A Frontline Tool for Epidemiological Studies, but Not Predictive of Fibrinogen Binding Ability.
- Author
-
Dahyot S, Lebeurre J, Laumay F, Argemi X, Dubos C, Lemée L, Prévost G, François P, and Pestel-Caron M
- Abstract
Staphylococcus lugdunensis is increasingly recognized as a potent pathogen, responsible for severe infections with an outcome resembling that of Staphylococcus aureus . Here, we developed and evaluated a tool for S. lugdunensis typing, using DNA sequence analysis of the repeat-encoding region (R-domain) in the gene encoding the fibrinogen (Fg)-binding protein Fbl ( fbl -typing). We typed 240 S. lugdunensis isolates from various clinical and geographical origins. The length of the R-domain ranged from 9 to 52 repeats. fbl -typing identified 54 unique 18-bp repeat sequences and 92 distinct fbl -types. The discriminatory power of fbl -typing was higher than that of multilocus sequence typing (MLST) and equivalent to that of tandem repeat sequence typing. fbl -types could assign isolates to MLST clonal complexes with excellent predictive power. The ability to promote adherence to immobilized human Fg was evaluated for 55 isolates chosen to reflect the genetic diversity of the fbl gene. We observed no direct correlation between Fg binding ability and fbl -types. However, the lowest percentage of Fg binding was observed for isolates carrying a 5'-end frameshift mutation of the fbl gene and for those harboring fewer than 43 repeats in the R-domain. qRT-PCR assays for some isolates revealed no correlation between fbl gene expression and Fg binding capacity. In conclusion, this study shows that fbl -typing is a useful tool in S. lugdunensis epidemiology, especially because it is an easy, cost-effective, rapid and portable method (http://fbl-typing.univ-rouen.fr/). The impact of fbl polymorphism on the structure of the protein, its expression on the cell surface and in virulence remains to be determined.
- Published
- 2019
- Full Text
- View/download PDF
230. Altered bioavailability of epoxyeicosatrienoic acids is associated with conduit artery endothelial dysfunction in type 2 diabetic patients.
- Author
-
Duflot T, Moreau-Grangé L, Roche C, Iacob M, Wils J, Rémy-Jouet I, Cailleux AF, Leuillier M, Renet S, Li D, Morisseau C, Lamoureux F, Richard V, Prévost G, Joannidès R, and Bellien J
- Subjects
- Aged, Biomarkers blood, Case-Control Studies, Diabetes Mellitus, Type 2 diagnosis, Diabetes Mellitus, Type 2 physiopathology, Diabetic Angiopathies diagnosis, Diabetic Angiopathies physiopathology, Epoxide Hydrolases metabolism, Essential Hypertension diagnosis, Essential Hypertension physiopathology, Female, Humans, Hyperthermia, Induced, Male, Middle Aged, Nitric Oxide metabolism, Nitrites blood, Nitroglycerin administration & dosage, Radial Artery drug effects, Radial Artery physiopathology, Vasodilator Agents administration & dosage, Diabetes Mellitus, Type 2 blood, Diabetic Angiopathies blood, Eicosanoids blood, Essential Hypertension blood, Radial Artery metabolism, Vasodilation drug effects
- Abstract
Background: This pathophysiological study addressed the hypothesis that soluble epoxide hydrolase (sEH), which metabolizes the vasodilator and anti-inflammatory epoxyeicosatrienoic acids (EETs) to dihydroxyeicosatrienoic acids (DHETs), contributes to conduit artery endothelial dysfunction in type 2 diabetes., Methods and Results: Radial artery endothelium-dependent flow-mediated dilatation in response to hand skin heating was reduced in essential hypertensive patients (n = 9) and type 2 diabetic subjects with (n = 19) or without hypertension (n = 10) compared to healthy subjects (n = 36), taking into consideration cardiovascular risk factors, flow stimulus and endothelium-independent dilatation to glyceryl trinitrate. Diabetic patients but not non-diabetic hypertensive subjects displayed elevated whole blood reactive oxygen species levels and loss of NO release during heating, assessed by measuring local plasma nitrite variation. Moreover, plasma levels of EET regioisomers increased during heating in healthy subjects, did not change in hypertensive patients and decreased in diabetic patients. Correlation analysis showed in the overall population that the less NO and EETs bioavailability increases during heating, the more flow-mediated dilatation is reduced. The expression and activity of sEH, measured in isolated peripheral blood mononuclear cells, was elevated in diabetic but not hypertensive patients, leading to increased EETs conversion to DHETs. Finally, hyperglycemic and hyperinsulinemic euglycemic clamps induced a decrease in flow-mediated dilatation in healthy subjects and this was associated with an altered EETs release during heating., Conclusions: These results demonstrate that an increased EETs degradation by sEH and altered NO bioavailability are associated with conduit artery endothelial dysfunction in type 2 diabetic patients independently from their hypertensive status. The hyperinsulinemic and hyperglycemic state in these patients may contribute to these alterations. Trial registration NCT02311075. Registered December 8, 2014.
- Published
- 2019
- Full Text
- View/download PDF
231. Coagulase-Negative Staphylococci Pathogenomics.
- Author
-
Argemi X, Hansmann Y, Prola K, and Prévost G
- Subjects
- Genome, Bacterial, Genomics methods, Humans, Phylogeny, Staphylococcus classification, Staphylococcus pathogenicity, Virulence genetics, Virulence Factors genetics, Coagulase deficiency, Staphylococcal Infections microbiology, Staphylococcus genetics
- Abstract
Coagulase-negative Staphylococci (CoNS) are skin commensal bacteria. Besides their role in maintaining homeostasis, CoNS have emerged as major pathogens in nosocomial settings. Several studies have investigated the molecular basis for this emergence and identified multiple putative virulence factors with regards to Staphylococcus aureus pathogenicity. In the last decade, numerous CoNS whole-genome sequences have been released, leading to the identification of numerous putative virulence factors. Koch's postulates and the molecular rendition of these postulates, established by Stanley Falkow in 1988, do not explain the microbial pathogenicity of CoNS. However, whole-genome sequence data has shed new light on CoNS pathogenicity. In this review, we analyzed the contribution of genomics in defining CoNS virulence, focusing on the most frequent and pathogenic CoNS species: S. epidermidis , S. haemolyticus, S. saprophyticus , S. capitis , and S. lugdunensis .
- Published
- 2019
- Full Text
- View/download PDF
232. Panton-Valentine Leucocidin Proves Direct Neuronal Targeting and Its Early Neuronal and Glial Impacts a Rabbit Retinal Explant Model.
- Author
-
Liu X, Roux MJ, Picaud S, Keller D, Sauer A, Heitz P, Prévost G, and Gaucher D
- Subjects
- Animals, Cells, Cultured, Inflammation Mediators metabolism, Neuroglia metabolism, Neuroglia pathology, Neurons metabolism, Neurons pathology, Rabbits, Bacterial Toxins toxicity, Exotoxins toxicity, Leukocidins toxicity, Neuroglia drug effects, Neurons drug effects
- Abstract
: Panton-Valentine leukocidin (PVL) retinal intoxication induces glial activation and inflammatory response via the interaction with retinal neurons. In this study, rabbit retinal explant was used as a model to study neuronal and glial consequences of PVL intoxication. Retinal explants were treated with different concentrations of PVL. PVL location and neuronal and glial changes were examined using immunohistochemistry. Some inflammatory factors were quantified using RT-qPCR at 4 and 8 h. These results were compared with those of control explants. PVL co-localized rapidly with retinal ganglion cells and with horizontal cells. PVL induced Müller and microglial cell activation. Retinal structure was altered and some amacrine and microglial cells underwent apoptosis. Glial activation and cell apoptosis increased in a PVL concentration- and time-dependent manner. IL-6 and IL-8 expression increased in PVL-treated explants but less than in control explants, which may indicate that other factors were responsible for glial activation and retinal apoptosis. On retinal explants, PVL co-localized with neuronal cells and induced glial activation together with microglial apoptosis, which confirms previous results observed in in vivo model. Rabbit retinal explant seems to be suitable model to further study the process of PVL leading to glial activation and retinal cells apoptosis., Competing Interests: The authors declare no conflict of interest.
- Published
- 2018
- Full Text
- View/download PDF
233. Comparative genomic analysis of Staphylococcus lugdunensis shows a closed pan-genome and multiple barriers to horizontal gene transfer.
- Author
-
Argemi X, Matelska D, Ginalski K, Riegel P, Hansmann Y, Bloom J, Pestel-Caron M, Dahyot S, Lebeurre J, and Prévost G
- Subjects
- CRISPR-Cas Systems genetics, Humans, Phylogeny, Sequence Analysis, DNA, Staphylococcal Infections microbiology, Virulence, Virulence Factors genetics, Gene Transfer, Horizontal genetics, Genome, Bacterial, Staphylococcus lugdunensis genetics
- Abstract
Background: Coagulase negative staphylococci (CoNS) are commensal bacteria on human skin. Staphylococcus lugdunensis is a unique CoNS which produces various virulence factors and may, like S. aureus, cause severe infections, particularly in hospital settings. Unlike other staphylococci, it remains highly susceptible to antimicrobials, and genome-based phylogenetic studies have evidenced a highly conserved genome that distinguishes it from all other staphylococci., Results: We demonstrate that S. lugdunensis possesses a closed pan-genome with a very limited number of new genes, in contrast to other staphylococci that have an open pan-genome. Whole-genome nucleotide and amino acid identity levels are also higher than in other staphylococci. We identified numerous genetic barriers to horizontal gene transfer that might explain this result. The S. lugdunensis genome has multiple operons encoding for restriction-modification, CRISPR/Cas and toxin/antitoxin systems. We also identified a new PIN-like domain-associated protein that might belong to a larger operon, comprising a metalloprotease, that could function as a new toxin/antitoxin or detoxification system., Conclusion: We show that S. lugdunensis has a unique genome profile within staphylococci, with a closed pan-genome and several systems to prevent horizontal gene transfer. Its virulence in clinical settings does not rely on its ability to acquire and exchange antibiotic resistance genes or other virulence factors as shown for other staphylococci.
- Published
- 2018
- Full Text
- View/download PDF
234. Multiple-Locus Variable Number Tandem Repeat Analysis (MLVA) and Tandem Repeat Sequence Typing (TRST), helpful tools for subtyping Staphylococcus lugdunensis.
- Author
-
Dahyot S, Lebeurre J, Argemi X, François P, Lemée L, Prévost G, and Pestel-Caron M
- Subjects
- Biodiversity, Humans, Linkage Disequilibrium genetics, Phylogeny, Staphylococcus lugdunensis isolation & purification, Genetic Loci, Minisatellite Repeats genetics, Staphylococcus lugdunensis classification, Staphylococcus lugdunensis genetics
- Abstract
Staphylococcus lugdunensis is an emergent virulent coagulase-negative Staphylococcus that is increasingly responsible for severe infections. In an attempt to generate informative sequence data for subtyping S. lugdunensis, we selected and sequenced seven polymorphic variable number of tandem repeats (VNTRs) to develop two new methods: a classic length-based multiple-locus VNTR analysis (MLVA) method and a tandem repeat sequence typing (TRST) method. We assessed their performances compared to two existing methods, multilocus sequence typing (MLST) and multivirulence-locus sequence typing (MVLST) for 128 isolates from diverse clinical settings and geographical origins. The clustering achieved by the four methods was highly congruent, with MLVA discriminating within clonal complexes as defined by MLST. Indeed, MLVA was highly discriminant compared to MLST and MVLST in terms of number of genotypes as well as diversity indexes. Sequencing of the seven VNTRs showed that they were stable, and analysis of sequence polymorphisms provided superior discriminatory power. The typeability, reproducibility, and epidemiological concordance of these new methods were excellent. Of note, no link between clustering and clinical settings was identified. This study demonstrates that MLVA and TRST provide valuable information for molecular epidemiological study of S. lugdunensis, and represent promising tools to distinguish between strains of homogenous lineages in this clonal species.
- Published
- 2018
- Full Text
- View/download PDF
235. Response of life-history traits to artificial and natural selection for virulence and nonvirulence in a Drosophila parastitoid, Asobara tabida.
- Author
-
Moiroux J, van Baaren J, Poyet M, Couty A, Eslin P, Prévost G, Séguin J, and Le Roux V
- Subjects
- Animals, Climate, Drosophila melanogaster parasitology, Female, Locomotion, Male, Reproduction, Selective Breeding, Virulence, Wasps genetics, Wasps growth & development, Host-Parasite Interactions genetics, Life History Traits, Selection, Genetic, Wasps pathogenicity
- Abstract
Co-evolution of host-parasitoid interactions is determined by the costs of host resistance, which received empirical evidence, and the costs of parasitoid virulence, which have been mostly hypothesized. Asobara tabida is a parasitoid, which mainly parasitizes Drosophila melanogaster and D. subobscura, the first species being able to resist to the parasitoid development while the second species is not. To parasitize resistant hosts, including D. melanogaster, A. tabida develops sticky eggs, which prevent encapsulation, but this virulence mechanism may be costly. Interindividual and interpopulation variation in the proportion of sticky eggs respectively allowed us to (i) artificially select and compare life-history traits of a virulent and a nonvirulent laboratory strain, and (ii) compare a virulent and a nonvirulent field strain, to investigate the hypothetical costs of virulence. We observed strong differences between the 2 laboratory strains. The nonvirulent strain invested fewer resources in reproduction and walked less than the virulent one but lived longer. Concerning the field strains, we observed that the nonvirulent strain had larger wings while the virulent one walked more and faster. All together, our results suggest that virulence may not always be costly, but rather that different life histories associated with different levels of virulence may coexist at both intra- and interpopulation levels., (© 2016 Institute of Zoology, Chinese Academy of Sciences.)
- Published
- 2018
- Full Text
- View/download PDF
236. Characterization of Human Type C Enterotoxin Produced by Clinical S. epidermidis Isolates.
- Author
-
Nanoukon C, Affolabi D, Keller D, Tollo R, Riegel P, Baba-Moussa L, and Prévost G
- Subjects
- Cell Proliferation drug effects, Cytokines metabolism, Humans, Leukocytes, Mononuclear drug effects, Leukocytes, Mononuclear physiology, Recombinant Proteins chemistry, Recombinant Proteins pharmacology, T-Lymphocytes drug effects, T-Lymphocytes physiology, Enterotoxins chemistry, Enterotoxins metabolism, Enterotoxins pharmacology, Staphylococcus epidermidis physiology, Superantigens chemistry, Superantigens metabolism, Superantigens pharmacology
- Abstract
Staphylococcal Enterotoxins (SEs) are superantigens (SAg) originally produced by S. aureus , but their presence in coagulase negative staphylococci (CNS) has long been suspected. This study aims to better characterize a novel C-like enterotoxin expressed by clinical S. epidermidis strains, called SEC
epi . We isolated and characterized SECepi for its molecular and functional properties. The toxin was structurally modeled according to its significant similarity with S. aureus SEC3. Most of SEC amino acid residues important for the formation of the trimolecular Major Histocompatibility Complex II MHCII-SEC-T Cell Receptor TCR complex are conserved in SECepi . The functional properties of SECepi were estimated after cloning, expression in E. coli , and purification. The recombinant SECepi toxin exhibits biological characteristics of a SAg including stimulation of human T-cell mitogenicity, inducing and releasing high cytokines levels: IL-2, -4, -6, -8, -10, IFN-γ, TNF-α and GM-CSF at a dose as low as 3.7 pM. Compared to SECaureus , the production of pro-sepsis cytokine IL-6 is significantly higher with SECepi -activated lymphocytes. Furthermore, SECepi is stable to heat, pepsin or trypsin hydrolysis. The SECepi superantigen produced by CNS is functionally very close to that of S. aureus , possibly inducing a systemic inflammatory response at least comparable to that of SECaureus , and may account for S. epidermidis pathogenicity., Competing Interests: The authors declare no conflicts of interest.- Published
- 2018
- Full Text
- View/download PDF
237. Comparative Genomics and Identification of an Enterotoxin-Bearing Pathogenicity Island, SEPI-1/SECI-1, in Staphylococcus epidermidis Pathogenic Strains.
- Author
-
Argemi X, Nanoukon C, Affolabi D, Keller D, Hansmann Y, Riegel P, Baba-Moussa L, and Prévost G
- Subjects
- Genomic Islands, Genomics, Staphylococcus aureus genetics, Enterotoxins genetics, Staphylococcus epidermidis genetics
- Abstract
Staphylococcus epidermidis is a leading cause of nosocomial infections, majorly resistant to beta-lactam antibiotics, and may transfer several mobile genetic elements among the members of its own species, as well as to Staphylococcus aureus ; however, a genetic exchange from S. aureus to S. epidermidis remains controversial. We recently identified two pathogenic clinical strains of S. epidermidis that produce a staphylococcal enterotoxin C3-like (SEC) similar to that by S. aureus pathogenicity islands. This study aimed to determine the genetic environment of the SEC-coding sequence and to identify the mobile genetic elements. Whole-genome sequencing and annotation of the S. epidermidis strains were performed using Illumina technology and a bioinformatics pipeline for assembly, which provided evidence that the SEC-coding sequences were located in a composite pathogenicity island that was previously described in the S. epidermidis strain FRI909, called SePI-1/SeCI-1, with 83.8-89.7% nucleotide similarity. Various other plasmids were identified, particularly p_3_95 and p_4_95, which carry antibiotic resistance genes ( hsrA and dfrG , respectively), and share homologies with SAP085A and pUSA04-2-SUR11, two plasmids described in S. aureus . Eventually, one complete prophage was identified, ΦSE90, sharing 30 out of 52 coding sequences with the Acinetobacter phage vB_AbaM_IME200. Thus, the SePI-1/SeCI-1 pathogenicity island was identified in two pathogenic strains of S. epidermidis that produced a SEC enterotoxin causing septic shock. These findings suggest the existence of in vivo genetic exchange from S. aureus to S. epidermidis ., Competing Interests: The authors declare no conflict of interest.
- Published
- 2018
- Full Text
- View/download PDF
238. Panton-Valentine Leukocidin Colocalizes with Retinal Ganglion and Amacrine Cells and Activates Glial Reactions and Microglial Apoptosis.
- Author
-
Liu X, Heitz P, Roux M, Keller D, Bourcier T, Sauer A, Prévost G, and Gaucher D
- Subjects
- Animals, Biological Transport, Gene Expression Regulation, Interleukin-6 metabolism, Rabbits, Tyrosine analogs & derivatives, Tyrosine metabolism, Amacrine Cells metabolism, Apoptosis, Bacterial Toxins metabolism, Exotoxins metabolism, Leukocidins metabolism, Microglia cytology, Retinal Ganglion Cells metabolism
- Abstract
Experimental models have established Panton-Valentine leukocidin (PVL) as a potential critical virulence factor during Staphylococcus aureus endophthalmitis. In the present study, we aimed to identify retinal cell targets for PVL and to analyze early retinal changes during infection. After the intravitreous injection of PVL, adult rabbits were euthanized at different time points (30 min, 1, 2, 4 and 8 h). PVL location in the retina, expression of its binding receptor C5a receptor (C5aR), and changes in Müller and microglial cells were analyzed using immunohistochemistry, Western blotting and RT-qPCR. In this model of PVL eye intoxication, only retinal ganglion cells (RGCs) expressed C5aR, and PVL was identified on the surface of two kinds of retinal neural cells. PVL-linked fluorescence increased in RGCs over time, reaching 98% of all RGCs 2 h after PVL injection. However, displaced amacrine cells (DACs) transiently colocalized with PVL. Müller and microglial cells were increasingly activated after injection over time. IL-6 expression in retina increased and some microglial cells underwent apoptosis 4 h and 8 h after PVL infection, probably because of abnormal nitrotyrosine production in the retina.
- Published
- 2018
- Full Text
- View/download PDF
239. D-Cateslytin, a new antimicrobial peptide with therapeutic potential.
- Author
-
Zaet A, Dartevelle P, Daouad F, Ehlinger C, Quilès F, Francius G, Boehler C, Bergthold C, Frisch B, Prévost G, Lavalle P, Schneider F, Haïkel Y, Metz-Boutigue MH, and Marban C
- Subjects
- Anti-Infective Agents chemical synthesis, Anti-Infective Agents toxicity, Antimicrobial Cationic Peptides chemical synthesis, Antimicrobial Cationic Peptides toxicity, Caco-2 Cells, Cell Membrane drug effects, Cell Survival drug effects, Cell Wall drug effects, Chromogranin A chemical synthesis, Chromogranin A toxicity, Drug Synergism, Epithelial Cells drug effects, Firmicutes drug effects, Humans, Microbial Sensitivity Tests, Microbial Viability drug effects, Peptide Fragments chemical synthesis, Peptide Fragments toxicity, Permeability drug effects, Prevotella intermedia drug effects, Anti-Infective Agents pharmacology, Antimicrobial Cationic Peptides pharmacology, Chromogranin A pharmacology, Escherichia coli drug effects, Peptide Fragments pharmacology
- Abstract
The rise of antimicrobial resistant microorganisms constitutes an increasingly serious threat to global public health. As a consequence, the efficacy of conventional antimicrobials is rapidly declining, threatening the ability of healthcare professionals to cure common infections. Over the last two decades host defense peptides have been identified as an attractive source of new antimicrobials. In the present study, we characterized the antibacterial and mechanistic properties of D-Cateslytin (D-Ctl), a new epipeptide derived from L-Cateslytin, where all L-amino acids were replaced by D-amino acids. We demonstrated that D-Ctl emerges as a potent, safe and robust peptide antimicrobial with undetectable susceptibility to resistance. Using Escherichia coli as a model, we reveal that D-Ctl targets the bacterial cell wall leading to the permeabilization of the membrane and the death of the bacteria. Overall, D-Ctl offers many assets that make it an attractive candidate for the biopharmaceutical development of new antimicrobials either as a single therapy or as a combination therapy as D-Ctl also has the remarkable property to potentiate several antimicrobials of reference such as cefotaxime, amoxicillin and methicillin.
- Published
- 2017
- Full Text
- View/download PDF
240. Effect of food deprivation on the hypothalamic gene expression of the secretogranin II-derived peptide EM66 in rat.
- Author
-
Trebak F, Dubuc I, Picot M, Alaoui A, Leprince J, Prévost G, Anouar Y, Magoul R, and Chartrel N
- Subjects
- Animals, Behavior, Animal physiology, Gene Expression physiology, Male, Peptide Fragments metabolism, RNA, Messenger metabolism, Rats, Rats, Wistar, Time Factors, Feeding Behavior physiology, Food Deprivation, Hypothalamus metabolism, Neuropeptide Y metabolism, Pro-Opiomelanocortin metabolism, Secretogranin II metabolism
- Abstract
EM66 is a peptide derived from the chromogranin, secretogranin II (SG-II). Recent findings in mice indicate that EM66 is a novel anorexigenic neuropeptide that regulates hypothalamic feeding behavior, at least in part, by activating the POMC neurons of the arcuate nucleus. The present study aimed to investigate the mechanism of action of EM66 in the control of feeding behavior and, more specifically, its potential interactions with the NPY and POMC systems in rat. We analyzed by Q-PCR the gene expression of the EM66 precursor, SG-II, in hypothalamic extracts following 2, 3, or 4 days of food deprivation and compared it with the expression levels of the two major neuropeptidergic systems, that is, POMC and NPY, modulating feeding behavior. Our results show that fasting for 2 and 3 days has no effect on SG-II mRNA levels. However, 4 days of food deprivation induced a significant alteration in the expression levels of the three genes studied, with a significant increase in SG-II and NPY mRNAs, and conversely, a significant decrease in POMC mRNA. These data indicate that the EM66 gene expression is modulated by a negative energy status and suggest interactions between EM66 and NPY to regulate food intake through the POMC system.
- Published
- 2017
- Full Text
- View/download PDF
241. Staphylococcus lugdunensis small colony variant conversion resulting in chronic prosthetic joint infection.
- Author
-
Argemi X, Dahyot S, Lebeurre J, Hansmann Y, Ronde Oustau C, and Prévost G
- Subjects
- Aged, Chronic Disease, Female, Humans, Arthritis, Infectious microbiology, Knee Prosthesis adverse effects, Prosthesis-Related Infections microbiology, Staphylococcal Infections microbiology, Staphylococcus lugdunensis
- Published
- 2017
- Full Text
- View/download PDF
242. Is Staphylococcus lugdunensis Significant in Clinical Samples?
- Author
-
Argemi X, Hansmann Y, Riegel P, and Prévost G
- Subjects
- Humans, Staphylococcus lugdunensis pathogenicity, Virulence Factors analysis, Staphylococcal Infections epidemiology, Staphylococcal Infections microbiology, Staphylococcus lugdunensis isolation & purification
- Abstract
The implication of coagulase-negative staphylococci in human diseases is a major issue, particularly in hospital settings wherein these species often act as opportunistic pathogens. In addition, some coagulase-negative staphylococci such as S. lugdunensis have emerged as pathogenic bacteria, implicated in severe infections, particularly, osteoarticular infections, foreign-body-associated infections, bacteremia, and endocarditis. In vitro studies have shown the presence of several putative virulence factors such as adhesion factors, biofilm production, and proteolytic factors that might explain clinical manifestations. Taken together, the clinical and microbiological data might change the way clinicians and microbiologists look at S. lugdunensis in clinical samples., (Copyright © 2017 American Society for Microbiology.)
- Published
- 2017
- Full Text
- View/download PDF
243. Kinetics of biofilm formation by Staphylococcus lugdunensis strains in bone and joint infections.
- Author
-
Argemi X, Prévost G, Riegel P, Provot C, Badel-Berchoux S, Jehl F, Olivares E, and Hansmann Y
- Subjects
- Aged, Female, Humans, Kinetics, Male, Middle Aged, Biofilms growth & development, Bone and Bones microbiology, Joints microbiology, Staphylococcal Infections microbiology, Staphylococcus lugdunensis growth & development
- Abstract
Objective: To describe the clinical presentation and 1-year follow-up of patients with bone and joint infections (BJIs) caused by Staphylococcus lugdunensis and evaluate its biofilm-forming capacities., Patients and Methods: Overall, 28 patients with BJIs from VISLISI clinical trials were included. We evaluated 1-year clinical follow-up and analyzed biofilm production kinetics of the 28 strains using the BioFilm Ring Test®., Results: Of all patients, 12 had osteoarticular infections without material and 16 had prosthetic joint infections, of which 9 underwent a 1-stage revision procedure. At the 1-year follow-up, all patients were cured but needed a surgical intervention. Diabetes affected 46.4% of all patients. Of all, 20 strains (71.4%) started biofilm formation within 2 h, but all strains started the formation after 4 h experiment, and 25 strains (89.3%) reached a maximum after 6 h., Conclusions: This study describes the clinical and surgical management of BJIs caused by S. lugdunensis and shows that 1-stage prosthesis exchange procedures may be efficient. Further, It shows that biofilm production by this strain was not marginal and directly impacted clinical and surgical management., (Copyright © 2017 Elsevier Inc. All rights reserved.)
- Published
- 2017
- Full Text
- View/download PDF
244. Biochemical characterization and comparison of aspartylglucosaminidases secreted in venom of the parasitoid wasps Asobara tabida and Leptopilina heterotoma.
- Author
-
Coulette Q, Lemauf S, Colinet D, Prévost G, Anselme C, Poirié M, and Gatti JL
- Subjects
- Amino Acid Sequence, Animals, Aspartylglucosylaminase chemistry, Drosophila melanogaster parasitology, Models, Molecular, Sequence Alignment, Wasp Venoms chemistry, Wasps chemistry, Wasps metabolism, Aspartylglucosylaminase metabolism, Wasp Venoms metabolism, Wasps enzymology
- Abstract
Aspartylglucosaminidase (AGA) is a low-abundance intracellular enzyme that plays a key role in the last stage of glycoproteins degradation, and whose deficiency leads to human aspartylglucosaminuria, a lysosomal storage disease. Surprisingly, high amounts of AGA-like proteins are secreted in the venom of two phylogenetically distant hymenopteran parasitoid wasp species, Asobara tabida (Braconidae) and Leptopilina heterotoma (Cynipidae). These venom AGAs have a similar domain organization as mammalian AGAs. They share with them key residues for autocatalysis and activity, and the mature α- and β-subunits also form an (αβ)2 structure in solution. Interestingly, only one of these AGAs subunits (α for AtAGA and β for LhAGA) is glycosylated instead of the two subunits for lysosomal human AGA (hAGA), and these glycosylations are partially resistant to PGNase F treatment. The two venom AGAs are secreted as fully activated enzymes, they have a similar aspartylglucosaminidase activity and are both also efficient asparaginases. Once AGAs are injected into the larvae of the Drosophila melanogaster host, the asparaginase activity may play a role in modulating their physiology. Altogether, our data provide new elements for a better understanding of the secretion and the role of venom AGAs as virulence factors in the parasitoid wasps' success.
- Published
- 2017
- Full Text
- View/download PDF
245. Tobramycin and Amikacin Delay Adhesion and Microcolony Formation in Pseudomonas aeruginosa Cystic Fibrosis Isolates.
- Author
-
Olivares E, Badel-Berchoux S, Provot C, Jaulhac B, Prévost G, Bernardi T, and Jehl F
- Abstract
Cystic fibrosis (CF) patients are predisposed to chronic colonization of the major airways by Pseudomonas aeruginosa biofilms. Pulmonary infections, involving sessile bacteria, are the main cause of morbidity and mortality. As the eradication of antibiotic-resistant biofilms remains impossible, one key objective for the treatment of lung infections is to delay the switch of P. aeruginosa to a sessile phenotype. Few tools are currently available in hospital laboratories to evaluate the susceptibility of adherent microorganisms to antimicrobials. In this study, we used the Biofilm Ring Test
® , for the achievement of Antibiofilmograms® on CF clinical isolates. In comparison to standard antibiograms, these procedures allow the investigation of antibiotic effects on the biofilm formation by bacteria. To confirm the inter-assay reproducibility, conventional Crystal Violet assays were performed. To mimic the pathologic reality of CF, we also used a model allowing the biofilm growth on CF-derived cells. Results obtained from these three different assays showed that amikacin and tobramycin, the two favored aminoglycosides in CF therapies, were able to prevent the early adhesion of P. aeruginosa isolates. This promising inhibitory effect of antimicrobials confirm that biofilm setting up is governed by adaptive responses and depends on environmental conditions, as opposite processes of biofilm induction by aminoglycosides were previously described in literature. Finally, Antibiofilmograms® , whose given results are in concordance with other in vitro antibiotic susceptibility testing, appear to be useful for the optimisation of CF therapies by the selection of antimicrobials able to delay chronic infection establishment.- Published
- 2017
- Full Text
- View/download PDF
246. VISLISI trial, a prospective clinical study allowing identification of a new metalloprotease and putative virulence factor from Staphylococcus lugdunensis.
- Author
-
Argemi X, Prévost G, Riegel P, Keller D, Meyer N, Baldeyrou M, Douiri N, Lefebvre N, Meghit K, Ronde Oustau C, Christmann D, Cianférani S, Strub JM, and Hansmann Y
- Subjects
- Adult, Aged, Aged, 80 and over, Amino Acid Sequence, Aminoglycosides therapeutic use, Base Sequence, DNA, Bacterial genetics, Drug Resistance, Multiple, Bacterial, Erythromycin therapeutic use, Female, Fluoroquinolones therapeutic use, Follow-Up Studies, Fosfomycin therapeutic use, Fusidic Acid therapeutic use, Humans, Male, Metalloproteases metabolism, Methicillin therapeutic use, Middle Aged, Phosphonoacetic Acid therapeutic use, Prospective Studies, Sequence Analysis, DNA, Staphylococcal Infections diagnosis, Staphylococcal Infections drug therapy, Staphylococcus lugdunensis genetics, Staphylococcus lugdunensis pathogenicity, Vancomycin therapeutic use, Metalloproteases genetics, Staphylococcus lugdunensis enzymology, Virulence Factors genetics
- Abstract
Objective: Staphylococcus lugdunensis is a coagulase-negative staphylococcus that displays an unusually high virulence rate close to that of Staphylococcus aureus. It also shares phenotypic properties with S. aureus and several studies found putative virulence factors. The objective of the study was to describe the clinical manifestations of S. lugdunensis infections and investigate putative virulence factors., Method: We conducted a prospective study from November 2013 to March 2016 at the University Hospital of Strasbourg. Putative virulence factors were investigated by clumping factor detection, screening for proteolytic activity, and sequence analysis using tandem nano-liquid chromatography-mass spectrometry., Results: In total, 347 positive samples for S. lugdunensis were collected, of which 129 (37.2%) were from confirmed cases of S. lugdunensis infection. Eighty-one of these 129 patients were included in the study. Bone and prosthetic joints (PJI) were the most frequent sites of infection (n=28; 34.6%) followed by skin and soft tissues (n=23; 28.4%). We identified and purified a novel protease secreted by 50 samples (61.7%), most frequently associated with samples from deep infections and PJI (pr 0.97 and pr 0.91, respectively). Protease peptide sequencing by nano-liquid chromatography-mass spectrometry revealed a novel protease bearing 62.42% identity with ShpI, a metalloprotease secreted by Staphylococcus hyicus., Conclusion: This study confirms the pathogenicity of S. lugdunensis, particularly in bone and PJI. We also identified a novel metalloprotease called lugdulysin that may contribute to virulence., (Copyright © 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2017
- Full Text
- View/download PDF
247. Whole-Genome Sequencing of Seven Strains of Staphylococcus lugdunensis Allows Identification of Mobile Genetic Elements.
- Author
-
Argemi X, Martin V, Loux V, Dahyot S, Lebeurre J, Guffroy A, Martin M, Velay A, Keller D, Riegel P, Hansmann Y, Paul N, and Prévost G
- Subjects
- Genome, Bacterial, Genomic Islands, Interspersed Repetitive Sequences, Molecular Sequence Annotation, Prophages, Recombination, Genetic, Staphylococcal Infections microbiology, Staphylococcus lugdunensis pathogenicity, Virulence Factors genetics, Staphylococcus lugdunensis classification, Staphylococcus lugdunensis genetics
- Abstract
Coagulase negative staphylococci are normal inhabitant of the human skin flora that account for an increasing number of infections, particularly hospital-acquired infections. Staphylococcus lugdunensis has emerged as a most virulent species causing various infections with clinical characteristics close to what clinicians usually observe with Staphylococcus aureus and both bacteria share more than 70% of their genome. Virulence of S. aureus relies on a large repertoire of virulence factors, many of which are encoded on mobile genetic elements. S. lugdunensis also bears various putative virulence genes but only one complete genome with extensive analysis has been published with one prophage sequence (φSL2) and a unique plasmid was previously described. In this study, we performed de novo sequencing, whole genome assembly and annotation of seven strains of S. lugdunensis from VISLISI clinical trial. We searched for the presence of virulence genes and mobile genetics elements using bioinformatics tools. We identified four new prophages, named φSL2 to φSL4, belonging to the Siphoviridae class and five plasmids, named pVISLISI_1 to pVISLISI_5. Three plasmids are homologous to known plasmids that include, amongst others, one S. aureus plasmid. The two other plasmids were not described previously. This study provides a new context for the study of S. lugdunensis virulence suggesting the occurrence of several genetic recombination' with other staphylococci., (© The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.)
- Published
- 2017
- Full Text
- View/download PDF
248. A potential role for the secretogranin II-derived peptide EM66 in the hypothalamic regulation of feeding behaviour.
- Author
-
Trebak F, Dubuc I, Arabo A, Alaoui A, Boukhzar L, Maucotel J, Picot M, Cherifi S, Duparc C, Leprince J, Prévost G, Anouar Y, Magoul R, and Chartrel N
- Subjects
- Animals, Caloric Restriction, Food Preferences drug effects, Hypothalamus metabolism, Infusions, Intraventricular, Male, Mice, Mice, Inbred C57BL, Peptide Fragments administration & dosage, Secretogranin II administration & dosage, Secretogranin II chemistry, Appetite Regulation drug effects, Feeding Behavior drug effects, Hypothalamus drug effects, Peptide Fragments pharmacology, Secretogranin II pharmacology
- Abstract
EM66 is a conserved 66-amino acid peptide derived from secretogranin II (SgII), a member of the granin protein family. EM66 is widely distributed in secretory granules of endocrine and neuroendocrine cells, as well as in hypothalamic neurones. Although EM66 is abundant in the hypothalamus, its physiological function remains to be determined. The present study aimed to investigate a possible involvement of EM66 in the hypothalamic regulation of feeding behaviour. We show that i.c.v. administration of EM66 induces a drastic dose-dependent inhibition of food intake in mice deprived of food for 18 hours, which is associated with an increase of hypothalamic pro-opiomelanocortin (POMC) and melanocortin-3 receptor mRNA levels and c-Fos immunoreactivity in the POMC neurones of the arcuate nucleus. By contrast, i.c.v. injection of EM66 does not alter the hypothalamic expression of neuropeptide Y (NPY), or that of its Y1 and Y5 receptors. A 3-month high-fat diet (HFD) leads to an important decrease of POMC and SgII mRNA levels in the hypothalamus, whereas NPY gene expression is not affected. Finally, we show that a 48 hours of fasting in HFD mice decreases the expression of POMC and SgII mRNA, which is not observed in mice fed a standard chow. Taken together, the present findings support the view that EM66 is a novel anorexigenic neuropeptide regulating hypothalamic feeding behaviour, at least in part, by activating the POMC neurones of the arcuate nucleus., (© 2017 British Society for Neuroendocrinology.)
- Published
- 2017
- Full Text
- View/download PDF
249. Above and beyond C5a Receptor Targeting by Staphylococcal Leucotoxins: Retrograde Transport of Panton-Valentine Leucocidin and γ-Hemolysin.
- Author
-
Zimmermann-Meisse G, Prévost G, and Jover E
- Subjects
- Apoptosis, Biological Transport, Calcium Signaling, Endoplasmic Reticulum metabolism, Endoplasmic Reticulum microbiology, Endosomes metabolism, Endosomes microbiology, Golgi Apparatus metabolism, Golgi Apparatus microbiology, Host-Pathogen Interactions, Humans, Kinetics, Lysosomes metabolism, Lysosomes microbiology, Neutrophils microbiology, Neutrophils pathology, Phosphorylation, Protein Binding, Protein Transport, Bacterial Proteins metabolism, Bacterial Toxins metabolism, Endocytosis, Exotoxins metabolism, Hemolysin Proteins metabolism, Leukocidins metabolism, Neutrophils metabolism, Receptor, Anaphylatoxin C5a metabolism, Staphylococcus aureus metabolism
- Abstract
Various membrane receptors associated with the innate immune response have recently been identified as mediators of the cellular action of Staphylococcus aureus leucotoxins. Two of these, the Panton-Valentine leucotoxin LukS-PV/LukF-PV and the γ-hemolysin HlgC/HlgB, bind the C5a complement-derived peptide receptor. These leucotoxins utilize the receptor to induce intracellular Ca
2+ release from internal stores, other than those activated by C5a. The two leucotoxins are internalized with the phosphorylated receptor, but it is unknown whether they divert retrograde transport of the receptor or follow another pathway. Immunolabeling and confocal microscopic techniques were used to analyze the presence of leucotoxins in endosomes, lysosomes, endoplasmic reticulum, and Golgi. The two leucotoxins apparently followed retrograde transport similar to that of the C5a peptide-activated receptor. However, HlgC/HlgB reached the Golgi network very early, whereas LukS-PV/LukF-PV followed slower kinetics. The HlgC/HlgB leucotoxin remained in neutrophils 6 h after a 10-min incubation of the cells in the presence of the toxin with no signs of apoptosis, whereas apoptosis was observed 3 h after neutrophils were incubated with LukS-PV/LukF-PV. Such retrograde transport of leucotoxins provides a novel understanding of the cellular effects initiated by sublytic concentrations of these toxins., Competing Interests: Conflicts of InterestThe funding agencies had no role in the study design, data collection or analysis, decision to publish, or preparation of the manuscript. None of the results obtained are part of a patent or commercial product. E.J. is permanent staff of the CNRS (governmental) and G.P. is a permanent faculty member of the Université de Strasbourg. None of the authors has a conflict of interest to declare.- Published
- 2017
- Full Text
- View/download PDF
250. Excess Body Mass Index Loss at 3 Months: A Predictive Factor of Long-Term Result after Sleeve Gastrectomy.
- Author
-
Philouze G, Voitellier E, Lacaze L, Huet E, Gancel A, Prévost G, Bubenheim M, and Scotté M
- Subjects
- Adult, Female, Gastrectomy, Humans, Linear Models, Male, Postoperative Complications, Predictive Value of Tests, Retrospective Studies, Treatment Outcome, Body Mass Index, Obesity, Morbid surgery, Weight Loss
- Abstract
Introduction. Laparoscopic Sleeve Gastrectomy (SG) is considered as successful if the percentage of Excess Body Mass Index Loss (% EBMIL) remains constant over 50% with long-term follow-up. The aim of this study was to evaluate whether early % EBMIL was predictive of success after SG. Methods. This retrospective study included patients who had SG with two years of follow-up. Patients had follow-up appointments at 3 (M3), 6, 12, and 24 months (M24). Data as weight and Body Mass Index (BMI) were collected systematically. We estimated the % EBMIL necessary to establish a correlation between M3 and M24 compared to % EBMIL speeds and calculated a limit value of % EBMIL predictive of success. Results. Data at operative time, M3, and M24 were available for 128 patients. Pearson test showed a correlation between % EBMIL at M3 and that at M24 ( r = 0.74; p < 0.0001). % EBMIL speed between surgery and M3 ( p = 0.0011) was significant but not between M3 and M24. A linear regression analysis proved that % EBMIL over 20.1% at M3 ( p < 0.0001) predicted a final % EBMIL over 50%. Conclusions. % EBMIL at M3 after SG is correlated with % EBMIL in the long term. % EBMIL speed was significant in the first 3 months. % EBMIL over 20.1% at M3 leads to the success of SG., Competing Interests: None of the authors (Guillaume Philouze, Emmanuel Huet, Antoine Gancel, Gaëtan Prévost, Michael Bubenheim, and Michel Scotté) declared any conflict of interests.
- Published
- 2017
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.