The Mre11-Rad50-Nbs1 complex mediates the robust recruitment of Polo to DNA lesions during mitosis in Drosophila

International audienceThe DNA damage sensor Mre11-Rad50-Nbs1 complex and Polo kinase are recruited to DNA lesions during mitosis. However, their mechanism of recruitment is elusive. Here, using live-cell imaging combined with micro-irradiation of single chromosomes, we analyze the dynamics of Polo and Mre11 at DNA lesions during mitosis in Drosophila. These two proteins display distinct kinetics. Whereas Polo kinetics at double-strand breaks (DSBs) are Cdk1-driven, Mre11 promptly but briefly associates with DSBs regardless of the phase of mitosis and re-associates with DSBs in the proceeding interphase. Mechanistically, Polo kinase activity is required for its own recruitment and that of the mitotic proteins BubR1 and Bub3 to DSBs. Moreover, depletion of Rad50 severely impaired Polo kinetics at mitotic DSBs. Conversely, ectopic tethering of Mre11 to chromatin was sufficient to recruit Polo. Our study highlights a novel pathway that links the DSB sensor Mre11-Rad50-Nbs1 complex and Polo kinase to initiate a prompt, decisive response to the presence of DNA damage during mitosis

Myosin efflux promotes cell elongation to coordinate chromosome segregation with cell cleavage

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A new type F Wolbachia from Splendidofilariinae (Onchocercidae) supports the recent emergence of this supergroup

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Bub3–BubR1-dependent sequestration of Cdc20Fizzy at DNA breaks facilitates the correct segregation of broken chromosomes

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Obesity in adult patients with inflammatory bowel disease: Clinical features and impact on disability. A cross-sectional survey from the GETAID

International audienceBackground: In recent years, an increasing prevalence of obesity in inflammatory bowel disease (IBD) has been observed. However, only a few studies have focused on the impact of overweight and obesity on IBD-related disability.Aims: To identify the factors associated with obese and overweight patients with IBD, including IBD-related disability.Patients and methods: In this cross-sectional study, we included 1704 consecutive patients with IBD in 42 centres affiliated with the Groupe d'Etude Therapeutique des Affections Inflammatoires du tube Digestif (GETAID) using a 4-page questionnaire. Factors associated with obesity and overweight were assessed using univariate and multivariate analyses (odds ratios (ORs) are provided with 95% confidence intervals).Results: The prevalence rates of overweight and obesity were 24.1% and 12.2%, respectively. Multivariable analyses were stratified by age, sex, type of IBD, clinical remission and age at diagnosis of IBD. Overweight was significantly associated with male sex (OR = 0.52, 95% CI [0.39-0.68], p < 0.001), age (OR = 1.02, 95% CI [1.01-1.03], p < 0.001) and body image subscore (OR = 1.15, 95% CI [1.10-1.20], p < 0.001) (Table 2). Obesity was significantly associated with age (OR = 1.03, 95% CI [1.02-1.04], p < 0.001), joint pain subscore (OR = 1.08, 95% CI [1.02-1.14], p < 0.001) and body image subscore (OR = 1.25, 95% CI [1.19-1.32], p < 0.001) (Table 3).Conclusion: The increasing prevalence of overweight and obesity in patients with IBD is associated with age and poorer body image. A holistic approach to IBD patient care should be encouraged to improve IBD-related disability and to prevent rheumatological and cardiovascular complications

Inherited CARD9 Deficiency: Invasive Disease Caused by Ascomycete Fungi in Previously Healthy Children and Adults

Abstract: Autosomal recessive CARD9 deficiency underlies life-threatening, invasive fungal infections in otherwise healthy individuals normally resistant to other infectious agents. In less than 10 years, 58 patients from 39 kindreds have been reported in 14 countries from four continents. The patients are homozygous (n = 49; 31 kindreds) or compound heterozygous (n = 9; 8 kindreds) for 22 different CARD9 mutations. Six mutations are recurrent, probably due to founder effects. Paradoxically, none of the mutant alleles has been experimentally demonstrated to be loss-of-function. CARD9 is expressed principally in myeloid cells, downstream from C-type lectin receptors that can recognize fungal components. Patients with CARD9 deficiency present impaired cytokine and chemokine production by macrophages, dendritic cells, and peripheral blood mononuclear cells and defective killing of some fungi by neutrophils in vitro. Neutrophil recruitment to sites of infection is impaired in vivo. The proportion of Th17 cells is low in most, but not all, patients tested. Up to 52 patients suffering from invasive fungal diseases (IFD) have been reported, with ages at onset of 3.5 to 52 years. Twenty of these patients also displayed superficial fungal infections. Six patients had only mucocutaneous candidiasis or superficial dermatophytosis at their last follow-up visit, at the age of 19 to 50 years. Remarkably, for 50 of the 52 patients with IFD, a single fungus was involved; only two patients had IFDs due to two different fungi. IFD recurred in 44 of 45 patients who responded to treatment, and a different fungal infection occurred in the remaining patient. Ten patients died from IFD, between the ages of 12 and 39 years, whereas another patient died at the age of 91 years, from an unrelated cause. At the most recent scheduled follow-up visit, 81% of the patients were still alive and aged from 6.5 to 75 years. Strikingly, all the causal fungi belonged to the phylum Ascomycota: commensal Candida and saprophytic Trychophyton, Aspergillus, Phialophora, Exophiala, Corynesprora, Aureobasidium, and Ochroconis. Human CARD9 is essential for protective systemic immunity to a subset of fungi from this phylum but seems to be otherwise redundant. Previously healthy patients with unexplained invasive fungal infection, at any age, should be tested for inherited CARD9 deficiency. Key Points: • Inherited CARD9 deficiency (OMIMSCOPUS: re.jinfo:eu-repo/semantics/publishe