Bim Nuclear Translocation and Inactivation by Viral Interferon Regulatory Factor

Viral replication efficiency is in large part governed by the ability of viruses to counteract pro-apoptotic signals induced by infection of the host cell. Human herpesvirus 8 (HHV-8) uses several strategies to block the host's innate antiviral defenses via interference with interferon and apoptotic signaling. Contributors include the four viral interferon regulatory factors (vIRFs 1–4), which function in dominant negative fashion to block cellular IRF activities in addition to targeting IRF signaling-induced proteins such as p53 and inhibiting other inducers of apoptosis such as TGFβ receptor-activated Smad transcription factors. Here we identify direct targeting by vIRF-1 of BH3-only pro-apoptotic Bcl-2 family member Bim, a key negative regulator of HHV-8 replication, to effect its inactivation via nuclear translocation. vIRF-1-mediated relocalization of Bim was identified in transfected cells, by both immunofluorescence assay and western analysis of fractionated cell extracts. Also, co-localization of vIRF-1 and Bim was detected in nuclei of lytically infected endothelial cells. In vitro co-precipitation assays using purified vIRF-1 and Bim revealed direct interaction between the proteins, and Bim-binding residues of vIRF-1 were mapped by deletion and point mutagenesis. Generation and experimental utilization of Bim-refractory vIRF-1 variants revealed the importance of vIRF-1:Bim interaction, specifically, in pro-replication and anti-apoptotic activity of vIRF-1. Furthermore, blocking of the interaction with cell-permeable peptide corresponding to the Bim-binding region of vIRF-1 confirmed the relevance of vIRF-1:Bim association to vIRF-1 pro-replication activity. To our knowledge, this is the first report of an IRF protein that interacts with a Bcl-2 family member and of nuclear sequestration of Bim or any other member of the family as a means of inactivation. The data presented reveal a novel mechanism utilized by a virus to control replication-induced apoptosis and suggest that inhibitory targeting of vIRF-1:Bim interaction may provide an effective antiviral strategy

Evaluation d'une maison médicale de garde dans un secteur rural de l'Indre

TOURS-BU Médecine (372612103) / SudocSudocFranceF

Incidence de la course sur l’apparition de FHL2 au sein des cellules de la moelle osseuse

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Impact of Treadmill Interval Running on the Appearance of Zinc Finger Protein FHL2 in Bone Marrow Cells in a Rat Model: A Pilot Study

International audienceAlthough the benefits of physical exercise to preserve bone quality are now widely recognized, the intimate mechanisms leading to the underlying cell responses still require further investigations. Interval training running, for instance, appears as a generator of impacts on the skeleton, and particularly on the progenitor cells located in the bone marrow. Therefore, if this kind of stimulus initiates bone cell proliferation and differentiation, the activation of a devoted signaling pathway by mechano-transduction seems likely. This study aimed at investigating the effects of an interval running program on the appearance of the zinc finger protein FHL2 in bone cells and their anatomical location. Twelve 5-week-old male Wistar rats were randomly allocated to one of the following groups (n = 6 per group): sedentary control (SED) or high-intensity interval running (EX, 8 consecutive weeks). FHL2 identification in bone cells was performed by immuno-histochemistry on serial sections of radii. We hypothesized that impacts generated by running could activate, in vivo, a specific signaling pathway, through an integrin-mediated mechano-transductive process, leading to the synthesis of FHL2 in bone marrow cells. Our data demonstrated the systematic appearance of FHL2 (% labeled cells: 7.5%, p < 0.001) in bone marrow obtained from EX rats, whereas no FHL2 was revealed in SED rats. These results suggest that the mechanical impacts generated during highintensity interval running activate a signaling pathway involving nuclear FHL2, such as that also observed with dexamethasone administration. Consequently, interval running could be proposed as a non-pharmacological strategy to contribute to bone marrow cell osteogenic differentiation

Different effects of Endurance versus Intermittent High Intensity runnings on activation of bone marrow cells

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Suprapubic versus transurethral catheterization for bladder drainage in male rectal cancer surgery (GRECCAR10), a randomized clinical trial

International audienceBackground: Bladder drainage is systematically used in rectal cancer surgery; however, the optimal type of drainage, transurethral catheterization (TUC) or suprapubic catheterization (SPC), is still controversial. The aim was to compare the rates of urinary tract infection on the fourth postoperative day (POD4) between TUC and SPC, after rectal cancer surgery regardless of the day of removal of the urinary drain.Methods: This randomized clinical trial in 19 expert colorectal surgery centers in France and Belgium was performed between October 2016 and October 2019 and included 240 men (with normal or subnormal voiding function) undergoing mesorectal excision with low anastomosis for rectal cancer. Patients were followed at postoperative days 4, 30, and 180.Results: In 208 patients (median age 66 years [IQR 58-71]) randomized to TUC (n = 99) or SPC (n = 109), the rate of urinary infection at POD4 was not significantly different whatever the type of drainage (11/99 (11.1%) vs. 8/109 (7.3%), 95% CI, - 4.2% to 11.7%; p = 0.35). There was significantly more pyuria in the TUC group (79/99 (79.0%) vs. (60/109 (60.9%), 95% CI, 5.7-30.0%; p = 0.004). No difference in bacteriuria was observed between the groups. Patients in the TUC group had a shorter duration of catheterization (median 4 [2-5] vs. 4 [3-5] days; p = 0.002). Drainage complications were more frequent in the SPC group at all followup visits.Conclusions: TUC should be preferred over SPC in male patients undergoing surgery for mid and/or lower rectal cancers, owing to the lower rate of complications and shorter duration of catheterization

Mitochondrial BCL-2 inhibits AMBRA1-induced autophagy

AMBRA1 is a positive regulator of BECLIN 1- dependent autophagy. Under basal conditions, AMBRA-1 is sequestered by Bcl-2 at the mitochondria. Upon induction of autophagy or apoptosis, AMBRA-1 is released to interact with BECLIN-1