Rôles des cytokines IL-6 et MCP-1 dans le recrutement précoce de macrophages antiinflammatoires lors de la phase aiguë de l’infarctus du myocarde : rôle de l’inflammasome NLRP3

Cardiovascular diseases remain the leading causes of mortality worldwide. Among cardiovascular diseases, myocardial infarction results from a coronary artery occlusion. This ischemic pathology activates inflammation mechanisms that could lead to secondary complications. Despite improved therapies, such as reperfusion, clinical management of complications remains a real challenge. Thus, understanding inflammatory mechanism development after myocardial infarction remains a major public health issue. The objective of the study is to evaluate the cytokines secretions and macrophages infiltration in the very acute phase of myocardial infarction. The thesis project is divided in three main axes, the first aimed to decipher the kinetics of the cytokinic secretions in patients suffering from myocardial infarction with ST segment elevation. The second axis, based on a murine model of myocardial infarction, is performed to evaluate the macrophage infiltration in whole organ in the first 24 hours of reperfusion in correlation with the systemic inflammatory status evaluated by the quantification of cytokine secretions in the sera. The third axis aimed to evaluate in vitro the ability of primary adult cardiac myocyte to induce macrophages recruitment and activation in response to an hypoxia-reoxygenation stress. This translational study demonstrates that several cytokines are secreted in response to myocardial infarction. Among cytokines, IL-6 and MCP-1 release reach a peak at 24h and a high level of those two cytokines is associated with the occurrence of major adverse cardiac event. We demonstrated that cardiac myocytes are at least partly responsible for these IL-6 and MCP-1 secretions and induce an anti-inflammatory macrophages recruitment. The acute anti-inflammatory macrophages recruitment is observed in the pre-clinical model of myocardial infarction. We finally shown that a reduction of acute anti-inflammatory macrophages leads to reduce infarct size. Taking together, the study results highlight the importance of the temporal kinetics of inflammation regulation and suggest that a too early anti-inflammatory mechanism activation may be deleterious.L’infarctus du myocarde touche environ 80 000 personnes par an en France chaque année. Malgré l’amélioration de la prise en charge des patients avec notamment le développement des techniques de reperfusion, la mortalité associée demeure trop élevée. Durant l’ensemble de la séquence d’ischémie et de reperfusion, un statut inflammatoire s’installe au niveau local et systémique. Ce projet de thèse a pour but de mieux décrire les évènements précoces afin d’améliorer les stratégies de cardioprotection visant l’inflammation dans l’infarctus du myocarde en se concentrant sur les sécrétions cytokiniques et l’infiltration des macrophages. Les travaux de thèse sont divisés en trois axes de travail avec un premier axe visant à déterminer les cinétiques de sécrétions cytokiniques dans une cohorte de patients souffrant d’un infarctus du myocarde avec élévation du segment ST. S’appuyant sur un modèle in vivo d’infarctus du myocarde, le second axe a pour but d’évaluer la cinétique d’infiltration cardiaque de macrophages en trois dimensions durant les 24 premières heures post infarctus en corrélation avec les sécrétions cytokiniques. Enfin, un troisième axe de travail s’appuie sur un modèle in vitro de culture de cardiomyocytes adultes primaires pour déterminer si les cardiomyocytes participent au recrutement et à l’activation précoce des macrophages. Cette étude translationnelle a permis de montrer qu’un grand nombre de cytokines étaient secrétées post infarctus, parmi lesquelles IL-6 et MCP-1 qui atteignent un pic de libération à 24H. Des taux circulants élevés d’IL-6 et de MCP-1 sont associés à la survenue d’évènements secondaires majeurs chez le patient. Nous avons également démontré que les cardiomyocytes souffrant sont au moins en partie responsable de ces secrétions systémiques et induisent un recrutement de macrophages anti-inflammatoires. Ce recrutement de macrophages anti-inflammatoire est observé également in vivo dans le modèle pré-clinique d’infarctus du myocarde. Enfin nous avons démontré qu’une réduction de ce recrutement précoce de macrophages anti-inflammatoires était bénéfique en réduisant la taille d’infarctus. L’ensemble des résultats de cette thèse démontrent l’importance de la notion de temporalité dans la régulation de l’inflammation post infarctus et suggèrent qu’une activation trop précoce des mécanismes anti-inflammatoires pourrait être délétère

Rôles des cytokines IL-6 et MCP-1 dans le recrutement précoce de macrophages antiinflammatoires lors de la phase aiguë de l’infarctus du myocarde : rôle de l’inflammasome NLRP3

Cardiovascular diseases remain the leading causes of mortality worldwide. Among cardiovascular diseases, myocardial infarction results from a coronary artery occlusion. This ischemic pathology activates inflammation mechanisms that could lead to secondary complications. Despite improved therapies, such as reperfusion, clinical management of complications remains a real challenge. Thus, understanding inflammatory mechanism development after myocardial infarction remains a major public health issue. The objective of the study is to evaluate the cytokines secretions and macrophages infiltration in the very acute phase of myocardial infarction. The thesis project is divided in three main axes, the first aimed to decipher the kinetics of the cytokinic secretions in patients suffering from myocardial infarction with ST segment elevation. The second axis, based on a murine model of myocardial infarction, is performed to evaluate the macrophage infiltration in whole organ in the first 24 hours of reperfusion in correlation with the systemic inflammatory status evaluated by the quantification of cytokine secretions in the sera. The third axis aimed to evaluate in vitro the ability of primary adult cardiac myocyte to induce macrophages recruitment and activation in response to an hypoxia-reoxygenation stress. This translational study demonstrates that several cytokines are secreted in response to myocardial infarction. Among cytokines, IL-6 and MCP-1 release reach a peak at 24h and a high level of those two cytokines is associated with the occurrence of major adverse cardiac event. We demonstrated that cardiac myocytes are at least partly responsible for these IL-6 and MCP-1 secretions and induce an anti-inflammatory macrophages recruitment. The acute anti-inflammatory macrophages recruitment is observed in the pre-clinical model of myocardial infarction. We finally shown that a reduction of acute anti-inflammatory macrophages leads to reduce infarct size. Taking together, the study results highlight the importance of the temporal kinetics of inflammation regulation and suggest that a too early anti-inflammatory mechanism activation may be deleterious.L’infarctus du myocarde touche environ 80 000 personnes par an en France chaque année. Malgré l’amélioration de la prise en charge des patients avec notamment le développement des techniques de reperfusion, la mortalité associée demeure trop élevée. Durant l’ensemble de la séquence d’ischémie et de reperfusion, un statut inflammatoire s’installe au niveau local et systémique. Ce projet de thèse a pour but de mieux décrire les évènements précoces afin d’améliorer les stratégies de cardioprotection visant l’inflammation dans l’infarctus du myocarde en se concentrant sur les sécrétions cytokiniques et l’infiltration des macrophages. Les travaux de thèse sont divisés en trois axes de travail avec un premier axe visant à déterminer les cinétiques de sécrétions cytokiniques dans une cohorte de patients souffrant d’un infarctus du myocarde avec élévation du segment ST. S’appuyant sur un modèle in vivo d’infarctus du myocarde, le second axe a pour but d’évaluer la cinétique d’infiltration cardiaque de macrophages en trois dimensions durant les 24 premières heures post infarctus en corrélation avec les sécrétions cytokiniques. Enfin, un troisième axe de travail s’appuie sur un modèle in vitro de culture de cardiomyocytes adultes primaires pour déterminer si les cardiomyocytes participent au recrutement et à l’activation précoce des macrophages. Cette étude translationnelle a permis de montrer qu’un grand nombre de cytokines étaient secrétées post infarctus, parmi lesquelles IL-6 et MCP-1 qui atteignent un pic de libération à 24H. Des taux circulants élevés d’IL-6 et de MCP-1 sont associés à la survenue d’évènements secondaires majeurs chez le patient. Nous avons également démontré que les cardiomyocytes souffrant sont au moins en partie responsable de ces secrétions systémiques et induisent un recrutement de macrophages anti-inflammatoires. Ce recrutement de macrophages anti-inflammatoire est observé également in vivo dans le modèle pré-clinique d’infarctus du myocarde. Enfin nous avons démontré qu’une réduction de ce recrutement précoce de macrophages anti-inflammatoires était bénéfique en réduisant la taille d’infarctus. L’ensemble des résultats de cette thèse démontrent l’importance de la notion de temporalité dans la régulation de l’inflammation post infarctus et suggèrent qu’une activation trop précoce des mécanismes anti-inflammatoires pourrait être délétère

Role of the cytokines IL-6 and MCP-1 in the acute anti-inflammatory macrophages recruitment during the early phase of myocardial infarction

L’infarctus du myocarde touche environ 80 000 personnes par an en France chaque année. Malgré l’amélioration de la prise en charge des patients avec notamment le développement des techniques de reperfusion, la mortalité associée demeure trop élevée. Durant l’ensemble de la séquence d’ischémie et de reperfusion, un statut inflammatoire s’installe au niveau local et systémique. Ce projet de thèse a pour but de mieux décrire les évènements précoces afin d’améliorer les stratégies de cardioprotection visant l’inflammation dans l’infarctus du myocarde en se concentrant sur les sécrétions cytokiniques et l’infiltration des macrophages. Les travaux de thèse sont divisés en trois axes de travail avec un premier axe visant à déterminer les cinétiques de sécrétions cytokiniques dans une cohorte de patients souffrant d’un infarctus du myocarde avec élévation du segment ST. S’appuyant sur un modèle in vivo d’infarctus du myocarde, le second axe a pour but d’évaluer la cinétique d’infiltration cardiaque de macrophages en trois dimensions durant les 24 premières heures post infarctus en corrélation avec les sécrétions cytokiniques. Enfin, un troisième axe de travail s’appuie sur un modèle in vitro de culture de cardiomyocytes adultes primaires pour déterminer si les cardiomyocytes participent au recrutement et à l’activation précoce des macrophages. Cette étude translationnelle a permis de montrer qu’un grand nombre de cytokines étaient secrétées post infarctus, parmi lesquelles IL-6 et MCP-1 qui atteignent un pic de libération à 24H. Des taux circulants élevés d’IL-6 et de MCP-1 sont associés à la survenue d’évènements secondaires majeurs chez le patient. Nous avons également démontré que les cardiomyocytes souffrant sont au moins en partie responsable de ces secrétions systémiques et induisent un recrutement de macrophages anti-inflammatoires. Ce recrutement de macrophages anti-inflammatoire est observé également in vivo dans le modèle pré-clinique d’infarctus du myocarde. Enfin nous avons démontré qu’une réduction de ce recrutement précoce de macrophages anti-inflammatoires était bénéfique en réduisant la taille d’infarctus. L’ensemble des résultats de cette thèse démontrent l’importance de la notion de temporalité dans la régulation de l’inflammation post infarctus et suggèrent qu’une activation trop précoce des mécanismes anti-inflammatoires pourrait être délétère.Cardiovascular diseases remain the leading causes of mortality worldwide. Among cardiovascular diseases, myocardial infarction results from a coronary artery occlusion. This ischemic pathology activates inflammation mechanisms that could lead to secondary complications. Despite improved therapies, such as reperfusion, clinical management of complications remains a real challenge. Thus, understanding inflammatory mechanism development after myocardial infarction remains a major public health issue. The objective of the study is to evaluate the cytokines secretions and macrophages infiltration in the very acute phase of myocardial infarction. The thesis project is divided in three main axes, the first aimed to decipher the kinetics of the cytokinic secretions in patients suffering from myocardial infarction with ST segment elevation. The second axis, based on a murine model of myocardial infarction, is performed to evaluate the macrophage infiltration in whole organ in the first 24 hours of reperfusion in correlation with the systemic inflammatory status evaluated by the quantification of cytokine secretions in the sera. The third axis aimed to evaluate in vitro the ability of primary adult cardiac myocyte to induce macrophages recruitment and activation in response to an hypoxia-reoxygenation stress. This translational study demonstrates that several cytokines are secreted in response to myocardial infarction. Among cytokines, IL-6 and MCP-1 release reach a peak at 24h and a high level of those two cytokines is associated with the occurrence of major adverse cardiac event. We demonstrated that cardiac myocytes are at least partly responsible for these IL-6 and MCP-1 secretions and induce an anti-inflammatory macrophages recruitment. The acute anti-inflammatory macrophages recruitment is observed in the pre-clinical model of myocardial infarction. We finally shown that a reduction of acute anti-inflammatory macrophages leads to reduce infarct size. Taking together, the study results highlight the importance of the temporal kinetics of inflammation regulation and suggest that a too early anti-inflammatory mechanism activation may be deleterious

Polygenic risk scores distinguish patients from non-affected adult relatives and from normal controls in Schizophrenia and Bipolar Disorder multi-affected kindreds

Recent studies have used results on SNP association with schizophrenia (SZ) and bipolar disorder (BD) to create polygenic risk scores (PRS) discriminating non‐familial unrelated patients from controls. Little is known about the role of PRS in densely affected multigenerational families. We tested PRS differences between affected SZ and BD family members from their non‐affected adult relatives (NAARs) in Eastern Quebec Kindreds and from controls. We examined 1227 subjects: from 17 SZ and BD kindreds, we studied 153 patients (57 SZ, 13 schizoaffective, and 83 BD) and 180 NAARs, and 894 unrelated controls from the Eastern Quebec population. PRS were derived from published case‐control association studies of SZ and BD. We also constructed a combined SZ and BD PRS by using SNPs from both SZ and BD PRS. SZ patients had higher SZ PRS than controls (p = 0.0039, R2 = 0.027) and BD patients had higher BD PRS than controls (p = 0.013, R2 = 0.027). Differences between affected subjects and NAARs and controls were significant with both SZ and BD PRS. Moreover, a combined SZ‐BD PRS was also significantly associated with SZ and BD when compared to NAARs (p = 0.0019, R2 = 0.010) and controls (p = 0.0025, R2 = 0.028), revealing a SZ‐BD commonality effect in PRS at the diagnosis level. The SZ and the BD PRS, however, showed a degree of specificity regarding thought disorder symptoms. Overall, our report would confirm the usefulness of PRS in capturing the contribution of common genetic variants to the risk of SZ and BD in densely affected families

The interaction of GSK3B and FXR1 genotypes may influence the mania and depression dimensions in mood disorders

Background: Previous evidence in healthy subjects suggested that functional polymorphisms GSK3B rs12630592 and FXR1 rs496250 interact in regulating mood and emotional processing. We attempted to replicate this interaction primarily on manic and depressive dimensions in mood disorder patients, and secondarily on schizophrenia patients, diagnosis itself and age of onset. Methods : Symptom dimensions were derived from the Comprehensive Assessment of Symptoms and History 82 items rated lifetime in acute episodes and stabilized interepisode intervals in 384 patients from the Schizophrenia and Bipolar Disorder Eastern Quebec Kindred Study. Linear mixed effect models of symptom dimensions included rs12630592-rs496250 main and interaction fixed effects (obtained from TaqMan genotypes), and a polygenic random effect. The distribution of lifetime best-estimate DSM-IV diagnosis of 855 kindred members was studied versus genotype under a polytomous logistic model. Results : In mood disorder patients, the level of mania (in both acute and stabilized periods) and depression in stabilized periods was positively associated with GSK3B rs12630592 T only in FXR1 rs496250 A-allele carriers (Bonferroni-corrected interaction p=0.024, 0.052 and 0.017 respectively). The two polymorphisms explained 11% of mania variance and 5% of interepisode depression variance. The association was observed neither in schizophrenia patients nor with the psychotic dimension in mood disorder patients. Interaction with the diagnosis distribution (p=0.03) was driven by the decreasing prevalence of recurrent major depression with rs12630592 T also only in carriers of rs496250 A. Limitations : Sample size was limited, but power was sufficient to detect the tested interaction effect in this replication sample. Conclusions : We replicate in affective patients an interaction between the FXR1 rs496250 and GSK3B rs12630592 polymorphisms in regulating mood dimensions

A multimodal attempt to follow-up linkage regions using RNA expression, SNPs and CpG methylation in schizophrenia and bipolar disorder kindreds

The complexity of schizophrenia (SZ) and bipolar disorder (BD) has slowed down progress in understanding their genetic roots. Alternative genomic approaches are needed to bypass these difficulties. We attempted a multimodal approach to follow-up on reported linkage findings in SZ and BD from the Eastern Quebec kindreds in chromosomes 3q21, 4p34, 6p22, 8p21, 8p11, 13q11-q14, 15q13, 16p12, and 18q21. First, in 498 subjects, we measured RNA expression (47 K Illumina chips) in SZ and BD patients that we compared with their non-affected relatives (NARs) to identify, for each chromosomal region, genes showing the most significant differences in expression. Second, we performed SNP genotyping (700 K Illumina chips) and cis-eQTN analysis. Third, we measured DNA methylation on genes with RNA expression differences or eQTNs. We found a significant overexpression of the gene ITGB5 at 3q25 in SZ and BD after multiple testing p value adjustment. SPCS3 gene at 4q34, and FZD3 gene at 8p21, contained significant eQTNs after multiple testing corrections, while ITGB5 provided suggestive results. Methylation in associated genes did not explain the expression differences between patients and NARs. Our multimodal approach involving RNA expression, dense SNP genotyping and eQTN analyses, restricted to chromosomal regions having shown linkage, lowered the multiple testing burden and allowed for a deeper examination of candidate genes in SZ or BD

Myocardial Ischemia-Reperfusion and Diabetes: Lessons Learned From Bedside to Bench

International audienceIn front of the failure to translate from bench to bedside cardioprotective drugs against myocardial ischemia-reperfusion, research scientists are currently revising their animal models. Owing to its growing incidence nowadays, type 2 diabetes (T2D) represents one of the main risk factors of co-morbidities in myocardial infarction. However, discrepancies exist between reported animal and human studies. Our aim was here to compare the impact of diabetes on cell death after cardiac ischemia-reperfusion in a human cohort of ST-elevation myocardial infarction (STEMI) patients with a diet-induced mouse model of T2D, using a high-fat high-sucrose diet for 16 weeks (HFHSD). Interestingly, a small fraction (<14%) of patients undergoing a myocardial infarct were diabetic, but treated, and did not show a bigger infarct size when compared to non-diabetic patients. On the contrary, HFHSD mice displayed an increased infarct size after an in vivo cardiac ischemia-reperfusion, together with an increased cell death after an in vitro hypoxia-reoxygenation on isolated cardiomyocytes. To mimic the diabetic patients' medication profile, 6 weeks of oral gavage with Metformin was performed in the HFHSD mouse group. Metformin treatment of the HFHSD mice led to a similar extent of lower cell death after hypoxia-reoxygenation as in the standard diet group, compared to the HFHSD cardiomyocytes. Altogether, our data highlight that due to their potential protective effect, anti-diabetic medications should be included in pre-clinical study of cardioprotective approaches. Moreover, since diabetic patients represent only a minor fraction of the STEMI patients, diabetic animal models may not be the most suitable translatable model to humans, unlike aging that appears as a common feature of all infarcted patients

IL-10/IL-6 serum ratio as a prognosis marker of STEMI

International audienc

IL-10/IL-6 serum ratio as a prognosis marker of STEMI

International audienc

A Dynamic Transcriptional Analysis Reveals IL-6 Axis as a Prominent Mediator of Surgical Acute Response in Non-ischemic Mouse Heart

International audienceBackground: Ischemic heart diseases are a major cause of death worldwide. Different animal models, including cardiac surgery, have been developed over time. Unfortunately, the surgery models have been reported to trigger an important inflammatory response that might be an effect modifier, where involved molecular processes have not been fully elucidated yet. Objective: We sought to perform a thorough characterization of the sham effect in the myocardium and identify the interfering inflammatory reaction in order to avoid misinterpretation of the data via systems biology approaches. Methods and Results: We combined a comprehensive analytical pipeline of mRNAseq dataset and systems biology analysis to characterize the acute phase response of mouse myocardium at 0 min, 45 min, and 24 h after surgery to better characterize the molecular processes inadvertently induced in sham animals. Our analysis showed that the surgical intervention induced 1209 differentially expressed transcripts (DETs). The clustering of positively co-regulated transcript modules at 45 min fingerprinted the activation of signalization pathways, while positively co-regulated genes at 24 h identified the recruitment of neutrophils and the differentiation of macrophages. In addition, we combined the prediction of transcription factors (TF) regulating DETs with proteinprotein interaction networks built from these TFs to predict the molecular network which have induced the DETs. By mean of this retro-analysis of processes upstream gene transcription, we revealed a major role of the Il-6 pathway and further confirmed a significant increase in circulating IL-6 at 45 min after surgery. Conclusion: This study suggests that a strong induction of the IL-6 axis occurs in sham animals over the first 24 h and leads to the induction of inflammation and tissues' homeostasis processes