PGC-1-Related Coactivator Modulates Mitochondrial-Nuclear Crosstalk through Endogenous Nitric Oxide in a Cellular Model of Oncocytic Thyroid Tumours

BACKGROUND:The PGC-1 related coactivator (PRC), which shares structural and functional features with PGC-1alpha, is believed to regulate several metabolic pathways as well as mitochondrial biogenesis. Its involvement in the early programming of cell proliferation suggests the existence of finely regulated crosstalk between mitochondrial functions and the cell cycle status. METHODOLOGY/PRINCIPAL FINDINGS:PRC-regulated pathways were explored in a cell-line model derived from mitochondrial-rich tumours with an essentially oxidative metabolism and specifically high PRC expression. The functional status of mitochondria was compared to the results of microarray analysis under conditions of temporal PRC inhibition. To specify the fine PRC regulation, the expression levels of the genes and proteins involved in the oxidative phosphorylation process were studied by real time quantitative PCR and western blotting. As in earlier studies on PGC-1alpha, we investigated the role of nitric oxide in PRC-regulated mitochondrial biogenesis and determined its action in the control of the phosphorylation status of the mitogen-activated protein kinase pathway. CONCLUSION/SIGNIFICANCE:We found that nitric oxide rapidly influences PRC expression at the transcriptional level. Focusing on mitochondrial energetic metabolism, we observed that PRC differentially controls respiratory chain complexes and coupling efficiency in a time-dependent manner to maintain mitochondrial homeostasis. Our results highlight the key role of PRC in the rapid modulation of metabolic functions in response to the status of the cell cycle

International initiative for a curated SDHB variant database improving the diagnosis of hereditary paraganglioma and pheochromocytoma

Funder: Cancer Research UK Cambridge Cancer CentreBackground: SDHB is one of the major genes predisposing to paraganglioma/pheochromocytoma (PPGL). Identifying pathogenic SDHB variants in patients with PPGL is essential to the management of patients and relatives due to the increased risk of recurrences, metastases and the emergence of non-PPGL tumours. In this context, the ‘NGS and PPGL (NGSnPPGL) Study Group’ initiated an international effort to collect, annotate and classify SDHB variants and to provide an accurate, expert-curated and freely available SDHB variant database. Methods: A total of 223 distinct SDHB variants from 737 patients were collected worldwide. Using multiple criteria, each variant was first classified according to a 5-tier grouping based on American College of Medical Genetics and NGSnPPGL standardised recommendations and was then manually reviewed by a panel of experts in the field. Results: This multistep process resulted in 23 benign/likely benign, 149 pathogenic/likely pathogenic variants and 51 variants of unknown significance (VUS). Expert curation reduced by half the number of variants initially classified as VUS. Variant classifications are publicly accessible via the Leiden Open Variation Database system (https://databases.lovd.nl/shared/genes/SDHB). Conclusion: This international initiative by a panel of experts allowed us to establish a consensus classification for 223 SDHB variants that should be used as a routine tool by geneticists in charge of PPGL laboratory diagnosis. This accurate classification of SDHB genetic variants will help to clarify the diagnosis of hereditary PPGL and to improve the clinical care of patients and relatives with PPGL

Primary hyperparathyroidism as first manifestation in multiple endocrine neoplasia type 2A: an international multicenter study.

Multiple endocrine neoplasia type 2A (MEN 2A) is a rare syndrome caused by RET germline mutations and has been associated with primary hyperparathyroidism (PHPT) in up to 30% of cases. Recommendations on RET screening in patients with apparently sporadic PHPT are unclear. We aimed to estimate the prevalence of cases presenting with PHPT as first manifestation among MEN 2A index cases and to characterize the former cases. An international retrospective multicenter study of 1085 MEN 2A index cases. Experts from MEN 2 centers all over the world were invited to participate. A total of 19 centers in 17 different countries provided registry data of index cases followed from 1974 to 2017. Ten cases presented with PHPT as their first manifestation of MEN 2A, yielding a prevalence of 0.9% (95% CI: 0.4-1.6). 9/10 cases were diagnosed with medullary thyroid carcinoma (MTC) in relation to parathyroid surgery and 1/10 was diagnosed 15 years after parathyroid surgery. 7/9 cases with full TNM data were node-positive at MTC diagnosis. Our data suggest that the prevalence of MEN 2A index cases that present with PHPT as their first manifestation is very low. The majority of index cases presenting with PHPT as first manifestation have synchronous MTC and are often node-positive. Thus, our observations suggest that not performing RET mutation analysis in patients with apparently sporadic PHPT would result in an extremely low false-negative rate, if no other MEN 2A component, specifically MTC, are found during work-up or resection of PHPT.S D received a national grant (AZV 16-32665A).S

Increasing the Number of Thyroid Lesions Classes in Microarray Analysis Improves the Relevance of Diagnostic Markers

BackgroundGenetic markers for thyroid cancers identified by microarray analysis have offered limited predictive accuracy so far because of the few classes of thyroid lesions usually taken into account. To improve diagnostic relevance, we have simultaneously analyzed microarray data from six public datasets covering a total of 347 thyroid tissue samples representing 12 histological classes of follicular lesions and normal thyroid tissue. Our own dataset, containing about half the thyroid tissue samples, included all categories of thyroid lesions. Methodology/Principal Findings Classifier predictions were strongly affected by similarities between classes and by the number of classes in the training sets. In each dataset, sample prediction was improved by separating the samples into three groups according to class similarities. The cross-validation of differential genes revealed four clusters with functional enrichments. The analysis of six of these genes (APOD, APOE, CLGN, CRABP1, SDHA and TIMP1) in 49 new samples showed consistent gene and protein profiles with the class similarities observed. Focusing on four subclasses of follicular tumor, we explored the diagnostic potential of 12 selected markers (CASP10, CDH16, CLGN, CRABP1, HMGB2, ALPL2, ADAMTS2, CABIN1, ALDH1A3, USP13, NR2F2, KRTHB5) by real-time quantitative RT-PCR on 32 other new samples. The gene expression profiles of follicular tumors were examined with reference to the mutational status of the Pax8-PPARγ, TSHR, GNAS and NRAS genes. Conclusion/Significance We show that diagnostic tools defined on the basis of microarray data are more relevant when a large number of samples and tissue classes are used. Taking into account the relationships between the thyroid tumor pathologies, together with the main biological functions and pathways involved, improved the diagnostic accuracy of the samples. Our approach was particularly relevant for the classification of microfollicular adenomas

Letter in response to remote ischaemic conditioning provides humoral cross-species cardioprotection through glycine receptor activation

International audienceO

Marqueurs de différenciation thyroïdienne et de prolifération mitochondriale dans le modèle des tumeurs oncocytaires

Les tumeurs thyroïdiennes papillaires et folliculaires malignes comportent un nombre plus élevé de mitochondries que les tumeurs folliculaires bénignes, soulevant l'hypothèse d'un lien entre prolifération mitochondriale et malignité. Le rôle spécifique des cellules thyroïdiennes dans la prolifération mitochondriale a été abordé par l'étude des oncocytomes, tumeurs riches en mitochondries, dont la fréquence est plus élevée dans la thyroïde que dans les autres tissus épithéliaux. Si la prolifération mitochondriale des oncocytomes n'est pas liée à un déficit de la chaîne respiratoire, ce travail montre qu'il est en rapport avec une surexpression de la voie de régulation de la biogenèse mitochondriale. Nous avons également montré que le métabolisme oxydatif est maintenu dans la lignée cellulaire XTC.UC1 issue d'un oncocytome. Ce phénomène nous semble secondaire à une stimulation importante et concomitante de la prolifération mitochondriale et de la voie de régulation de la prolifération cellulaire, favorisant d'autant plus l'utilisation de la voie oxydative que ces tumeurs sont très vascularisées.ANGERS-BU Médecine-Pharmacie (490072105) / SudocSudocFranceF

Marqueurs de différenciation thyroïdienne et de prolifération mitochondriale dans le modèle des tumeurs oncocytaires

Les tumeurs thyroïdiennes papillaires et folliculaires malignes comportent un nombre plus élevé de mitochondries que les tumeurs folliculaires bénignes, soulevant l'hypothèse d'un lien entre prolifération mitochondriale et malignité. Le rôle spécifique des cellules thyroïdiennes dans la prolifération mitochondriale a été abordé par l'étude des oncocytomes, tumeurs riches en mitochondries, dont la fréquence est plus élevée dans la thyroïde que dans les autres tissus épithéliaux. Si la prolifération mitochondriale des oncocytomes n'est pas liée à un déficit de la chaîne respiratoire, ce travail montre qu'il est en rapport avec une surexpression de la voie de régulation de la biogenèse mitochondriale. Nous avons également montré que le métabolisme oxydatif est maintenu dans la lignée cellulaire XTC.UC1 issue d'un oncocytome. Ce phénomène nous semble secondaire à une stimulation importante et concomitante de la prolifération mitochondriale et de la voie de régulation de la prolifération cellulaire, favorisant d'autant plus l'utilisation de la voie oxydative que ces tumeurs sont très vascularisées.ANGERS-BU Médecine-Pharmacie (490072105) / SudocSudocFranceF

INFLUENCE DE L'INACTIVATION DE MTS1, MTS2, ET MTAP DANS LES LEUCEMIES AIGUES LYMPHOBLASTIQUES DE L'ENFANT

PARIS-BIUM (751062103) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocSudocFranceF

Remote Ischemic Conditioning in a Model of Severe Renal Ischemia-Reperfusion Injury

International audienceIschemia-reperfusion (I/R) injury is a leading cause of acute renal dysfunction. Remote ischemic conditioning (rIC) is known to protect organs exposed to I/R. We sought to investigate whether rIC would influence renal function recovery in a severe renal I/R injury rat model. Rats were randomly assigned to four experimental groups following median laparotomy and right nephrectomy: Sham (n = 6); 30-min left renal ischemia (RI) only (n = 20); RI+rIC (n = 20) (four 5-min cycles of limb ischemia interspersed with 5-min limb reperfusion during RI); RI+erythropoietin pre-treatment (EPO) (n = 20). Renal function was evaluated by assessing blood urea nitrogen (BUN) and serum creatinine (Cr) levels before surgery and after 1 day of reperfusion. All animals were monitored for 7 days for survival analysis. BUN and Cr baseline levels did not significantly differ between groups. At Day 1, BUN and Cr were significantly higher than baseline values in all groups. BUN and Cr levels did not significantly differ at Day 1 between RI and RI+rIC (p = 0.68). Conversely, EPO pre-treatment injected 60 minutes before RI was associated with lower BUN and Cr levels compared to RI (p &lt; 0.001 and p = 0.003, respectively) and RI+rIC (p &lt; 0.001 and p = 0.001, respectively). In addition, 7-day survival rates were significantly higher in the Sham group (100%) compared to RI (50%; p = 0.039 vs Sham) and RI+rIC (45%; p = 0.026 vs Sham). Conversely, survival rate did not significantly differ between the Sham and RI+EPO groups (70%, p = 0.15). In conclusion, rIC affected neither acute renal dysfunction nor early mortality in a severe I/R renal injury rat model, contrary to EPO pre-treatment.</p

Cardioprotective Role of Colchicine Against Inflammatory Injury in a Rat Model of Acute Myocardial Infarction

International audienceBACKGROUND: Inflammation plays a crucial role in the pathophysiology of myocardial ischemia/reperfusion (I/R) injury. A clinical trial has recently reported a smaller infarct size in a cohort of patients with ST-segment elevation myocardial infarction (MI) treated with a short colchicine course. The mechanism underlying colchicine-induced cardioprotection in the early MI phase remains unclear. We hypothesized that a short pretreatment with colchicine could induce acute beneficial effects by protecting the heart against inflammation in myocardial I/R injury.METHODS AND RESULTS: Rats were subjected to 40-minute left anterior descending coronary occlusion, followed by 120-minute reperfusion. Colchicine (0.3 mg/kg) or a vehicle was administered per os 24 hours and immediately before surgery. Infarct size was significantly reduced in the colchicine group (35.6% ± 3.0% vs 46.6% ± 3.3%, P &lt; .05). The beneficial effects of colchicine were associated with an increased systemic interleukin-10 (IL-10) level and decreased cardiac transforming growth factor-β level. Interleukin-1β was found to increase in a "time of reperfusion"-dependent manner. Colchicine inhibited messenger RNA expression of caspase-1 and pro-IL-18. Interleukin-1β injected 10 minutes prior to myocardial ischemia induced greater infarct size (58.0% ± 2.0%, P &lt; .05) as compared to the vehicle. Colchicine combined to IL-1β injection significantly decreased infarct size (47.1% ± 2.2%, P &lt; .05) as compared to IL-1β alone, while colchicine alone exhibited a significantly more marked cardioprotective effect than the colchicine-IL-1β association.CONCLUSION: The cardioprotection induced by a short colchicine pretreatment was associated with an anti-inflammatory effect in the early reperfusion phase in our rat MI model.</p