Carboxy-terminal fragment of fibroblast growth factor 23 induces heart hypertrophy in sickle cell disease

International audienc

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Rôle de la chaperonne HSP 70 dans l'éythropoïèse inefficace des béta-thalassémies majeures

Β-TM is an inherited hemoglobinopathy caused by a quantitative defect in the synthesis of the β-globin chains of hemoglobin, leading to the accumulation of free α-globin chains that form toxic aggregates. Despite extensive knowledge on the molecular defects causing β-TM, little is known about the mechanisms responsible for ineffective erythropoiesis (IE), which is characterised by accelerated erythroid differentiation, maturation arrest and apoptosis at the polychromatophilic stage. We have previously demonstrated that normal human erythroid cell maturation requires a transient activation of caspase-3. Although GATA-1, the master transcriptional factor of erythropoiesis, is a caspase-3 target, we have shown that during human erythroid differentiation, it is protected from cleavage through its association with the chaperone Hsp70 in the nucleus. Hsp70 is constitutively highly expressed in normal human erythroid cells. The best-known role of this ubiquitous chaperone is to participate in proteins folding and refolding of proteins denatured by cytoplasmic stress, thus preventing their aggregation.In this study, we have evidenced that during the maturation of human β-TM erythroblasts, Hsp70 is sequestrated in the cytoplasm by the excess of free α-globin chains, resulting in nuclear GATA-1 cleavage and, in turn, end-stage maturation arrest and apoptosis. A molecular modeling shows that α-globin binds to a highly electronegative cavity formed by all Hsp70 domains. Additionally, the transduction of a nuclear-targeted Hsp70 mutant (Hsp70-S400A) or caspase-3 uncleavable GATA-1 mutant (µGATA-1) corrects β-TM ineffective erythropoiesis in human cultured β-TM cells. Our data indicate that cytosolic Hsp70 sequestration by α-globin chains prevents its nuclear localization and is a key mechanism of the β-TM IE. In order to increase nuclear Hsp70 translocation, developing small molecules that could increase Hsp70 expression or disrupt the Hsp70/α-globin complex could be a novel approach of targeted therapies to improve erythropoiesis in β-TM.L’érythropoïèse inefficace joue un rôle central dans la physiopathologie de l’anémie des β-TM. Ses caractéristiques sont triple: accélération de la différenciation érythroïde, arrêt de maturation au stade d’érythroblaste polychromatophile et mort par apoptose à ce stade de différenciation. Les mécanismes précis de cette apoptose et de l’arrêt de la maturation n’ont pas encore été élucidés. Il a été montré, au cours de l’érythropoïèse physiologique, que la protéine chaperonne Hsp70, en se localisant dans le noyau des érythroblastes en cours de différenciation, protège GATA-1 (facteur de transcription érythroïde majeur) de sa destruction par la caspase-3. Cette enzyme clé de l’apoptose est en effet activée physiologiquement au cours de la différenciation érythroïde et peut cliver GATA-1. Notre travail se base sur l’hypothèse suivante : Hsp70 pourrait, au cours de l’érythropoïèse des β-TM, être séquestrée dans le cytoplasme des érythroblastes matures (stade d’une intense hémoglobinisation) afin d’exercer son rôle de chaperonne des chaînes d’α-globine libres. Cela aurait comme conséquence néfaste l’absence de localisation nucléaire d’Hsp70 et, en conséquence, la destruction de GATA-1 à l’origine de l’arrêt de maturation et de la mort cellulaire. Nous avons montré dans ce travail qu’Hsp70 était localisée principalement dans le cytoplasme des érythroblastes matures dans la moelle de patients β-TM, avec un défaut d’expression nucléaire. Par ailleurs, GATA-1 n’est plus exprimé dans ces cellules. Nous avons confirmé ces résultats dans un système de culture cellulaire érythroïde humaine en milieu liquide reproduisant les étapes de la différenciation érythroïde terminale. Une intéraction physique directe entre Hsp70 et l’α-globine a été identifiée par techniques de microscopie confocale, d’immunoprécipitation et de double hybride. Enfin, la transduction dans les érythroblastes de β-TM d’un mutant d’Hsp70-S400A, principalement nucléaire, ou d’un mutant de GATA-1 non clivable par la caspase-3 corrige l’érythropoïèse inefficace.Une modélisation mathématique du complexe Hsp70/α-globine nous a permis de préciser les domaines impliqués dans l’intéraction, ce qui ouvre la voie à une possibilité de criblage de petites molécules permettant la rupture de ce complexe afin de ramener Hsp70 dans le noyau avec un espoir thérapeutique pour améliorer l’érythropoïèse inefficace des β-TM

Role of the chaperone Hsp70 in beta-thalassemia major (β-TM) ineffective erythropoiesis

L’érythropoïèse inefficace joue un rôle central dans la physiopathologie de l’anémie des β-TM. Ses caractéristiques sont triple: accélération de la différenciation érythroïde, arrêt de maturation au stade d’érythroblaste polychromatophile et mort par apoptose à ce stade de différenciation. Les mécanismes précis de cette apoptose et de l’arrêt de la maturation n’ont pas encore été élucidés. Il a été montré, au cours de l’érythropoïèse physiologique, que la protéine chaperonne Hsp70, en se localisant dans le noyau des érythroblastes en cours de différenciation, protège GATA-1 (facteur de transcription érythroïde majeur) de sa destruction par la caspase-3. Cette enzyme clé de l’apoptose est en effet activée physiologiquement au cours de la différenciation érythroïde et peut cliver GATA-1. Notre travail se base sur l’hypothèse suivante : Hsp70 pourrait, au cours de l’érythropoïèse des β-TM, être séquestrée dans le cytoplasme des érythroblastes matures (stade d’une intense hémoglobinisation) afin d’exercer son rôle de chaperonne des chaînes d’α-globine libres. Cela aurait comme conséquence néfaste l’absence de localisation nucléaire d’Hsp70 et, en conséquence, la destruction de GATA-1 à l’origine de l’arrêt de maturation et de la mort cellulaire. Nous avons montré dans ce travail qu’Hsp70 était localisée principalement dans le cytoplasme des érythroblastes matures dans la moelle de patients β-TM, avec un défaut d’expression nucléaire. Par ailleurs, GATA-1 n’est plus exprimé dans ces cellules. Nous avons confirmé ces résultats dans un système de culture cellulaire érythroïde humaine en milieu liquide reproduisant les étapes de la différenciation érythroïde terminale. Une intéraction physique directe entre Hsp70 et l’α-globine a été identifiée par techniques de microscopie confocale, d’immunoprécipitation et de double hybride. Enfin, la transduction dans les érythroblastes de β-TM d’un mutant d’Hsp70-S400A, principalement nucléaire, ou d’un mutant de GATA-1 non clivable par la caspase-3 corrige l’érythropoïèse inefficace.Une modélisation mathématique du complexe Hsp70/α-globine nous a permis de préciser les domaines impliqués dans l’intéraction, ce qui ouvre la voie à une possibilité de criblage de petites molécules permettant la rupture de ce complexe afin de ramener Hsp70 dans le noyau avec un espoir thérapeutique pour améliorer l’érythropoïèse inefficace des β-TM.Β-TM is an inherited hemoglobinopathy caused by a quantitative defect in the synthesis of the β-globin chains of hemoglobin, leading to the accumulation of free α-globin chains that form toxic aggregates. Despite extensive knowledge on the molecular defects causing β-TM, little is known about the mechanisms responsible for ineffective erythropoiesis (IE), which is characterised by accelerated erythroid differentiation, maturation arrest and apoptosis at the polychromatophilic stage. We have previously demonstrated that normal human erythroid cell maturation requires a transient activation of caspase-3. Although GATA-1, the master transcriptional factor of erythropoiesis, is a caspase-3 target, we have shown that during human erythroid differentiation, it is protected from cleavage through its association with the chaperone Hsp70 in the nucleus. Hsp70 is constitutively highly expressed in normal human erythroid cells. The best-known role of this ubiquitous chaperone is to participate in proteins folding and refolding of proteins denatured by cytoplasmic stress, thus preventing their aggregation.In this study, we have evidenced that during the maturation of human β-TM erythroblasts, Hsp70 is sequestrated in the cytoplasm by the excess of free α-globin chains, resulting in nuclear GATA-1 cleavage and, in turn, end-stage maturation arrest and apoptosis. A molecular modeling shows that α-globin binds to a highly electronegative cavity formed by all Hsp70 domains. Additionally, the transduction of a nuclear-targeted Hsp70 mutant (Hsp70-S400A) or caspase-3 uncleavable GATA-1 mutant (µGATA-1) corrects β-TM ineffective erythropoiesis in human cultured β-TM cells. Our data indicate that cytosolic Hsp70 sequestration by α-globin chains prevents its nuclear localization and is a key mechanism of the β-TM IE. In order to increase nuclear Hsp70 translocation, developing small molecules that could increase Hsp70 expression or disrupt the Hsp70/α-globin complex could be a novel approach of targeted therapies to improve erythropoiesis in β-TM

Syndrome hémophagocytaire au cours de la maladie de Still de l'adulte

PARIS6-Bibl. St Antoine CHU (751122104) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Rôle d’HSP70 dans l’érythropoïèse inefficace des β-thalassémies majeures

International audienc

Comparison between Adult Patients with Sickle Cell Disease of Sub-Saharan African Origin Born in Metropolitan France and in Sub-Saharan Africa

Sickle cell disease (SCD) prevalence has increased rapidly in Europe as a result of an increase in the life expectancy of these patients and the arrival of SCD migrants from Africa. The aim of our study was to compare the phenotypes of adult patients born in Sub-Saharan Africa (SSA) who migrated to France with those of patients with the same origin who were born in France. This single-center observational study compared the demographic, clinical and biological characteristics of SCD adult patients of SSA origin who were born in France or SSA. Data were collected from computerized medical charts. Groups were compared using multivariate logistic regression with adjustment for age, gender and type of SCD. Of the 323 SCD patients followed in our center, 235 were enrolled, including 111 patients born in France and 124 patients born in SSA. SCD genotypes were balanced between groups. Patients born in Africa were older (median age 32.1 (24.4–39) vs. 25.6 (22.1–30.5) years, p < 0.001) and more often women (n = 75 (60.5%) vs. 48 (43.2%), p = 0.008). The median age at arrival in France was 18 years (13–23). The median height was lower among patients born in SSA (169 (163–175) vs. 174.5 cm (168–179), p < 0.001). Over their lifetimes, patients born in France had more acute chest syndromes (median number 2 (1–4) vs. 1 (0–3), p = 0.002), with the first episode occurring earlier (19 (11.6–22.3) vs. 24 (18.4–29.5) years, p < 0.007), and were admitted to intensive care units more often (53.3% vs. 34.9%, p = 0.006). This difference was more pronounced in the SS/Sβ0 population. Conversely, patients born in SSA had more skin ulcers (19.4% vs. 6.3%, p = 0.03). No significant differences were found in social and occupational insertion or other complications between the two groups. Patients born in SSA had a less severe disease phenotype regardless of their age than those born in France. This difference could be related to a survival bias occurring in Africa during childhood and migration to Europe that selected the least severe phenotypes

Protein-based therapeutic for anemia caused by dyserythropoiesis

International audienc

Primary Hyperparathyroidism in Sickle Cell Disease: An Unknown Complication of the Disease in Adulthood

International audiencePrimary hyperparathyroidism (pHPT) is the third most common endocrine disorder and usually affects patients between 60 and 70 years of age. To our knowledge, this condition has never been studied in young patients with sickle cell disease (SCD). Our objective was to describe the clinical and biological characteristics of pHPT in adult patients with SCD and its management. We conducted a retrospective study that included SCD patients who were diagnosed with pHPT in four SCD referral centers. pHPT was defined by the presence of elevated serum calcium levels with inappropriate normal or increased parathyroid hormone (PTH) serum levels or histopathological evidence of parathyroid adenoma or hyperplasia. Patients with severe renal impairment (GFR <30 mL/min) were excluded. Twenty-eight patients (18 women, 64%; 22 homozygous genotype, 79%) were included. The median age at pHPT diagnosis was 41 years (interquartile range –IQR- 31.5–49.5). The median serum calcium and PTH concentration were, respectively, 2.62 mmol/L (IQR 2.60–2.78) and 105 pg/mL (IQR 69–137). Bone mineral density (BMD) revealed very low BMD (≤−2.5 SD) in 44% of patients explored (vs. 12.5% among 32 SCD patients matched for SCD genotype, sex, age, and BMI, p = 0.03). Fourteen patients (50%) received surgical treatment, which was successful in all cases, but four of these patients (29%) presented with pHPT recurrence after a median time of 6.5 years. Three of these patients underwent a second cervical surgery that confirmed the presence of a new parathyroid adenoma. These results suggest that SCD is a condition associated with pHPT in young subjects. SCD patients with pHPT have a high risk of very low BMD. A diagnosis of pHPT should be suspected in the presence of mild hypercalcemia or low BMD in SCD patients. View Full-Tex