De novo variants in the RNU4-2 snRNA cause a frequent neurodevelopmental syndrome.

Around 60% of individuals with neurodevelopmental disorders (NDD) remain undiagnosed after comprehensive genetic testing, primarily of protein-coding genes1. Large genome-sequenced cohorts are improving our ability to discover new diagnoses in the non-coding genome. Here we identify the non-coding RNA RNU4-2 as a syndromic NDD gene. RNU4-2 encodes the U4 small nuclear RNA (snRNA), which is a critical component of the U4/U6.U5 tri-snRNP complex of the major spliceosome2. We identify an 18 base pair region of RNU4-2 mapping to two structural elements in the U4/U6 snRNA duplex (the T-loop and stem III) that is severely depleted of variation in the general population, but in which we identify heterozygous variants in 115 individuals with NDD. Most individuals (77.4%) have the same highly recurrent single base insertion (n.64_65insT). In 54 individuals in whom it could be determined, the de novo variants were all on the maternal allele. We demonstrate that RNU4-2 is highly expressed in the developing human brain, in contrast to RNU4-1 and other U4 homologues. Using RNA sequencing, we show how 5 splice-site use is systematically disrupted in individuals with RNU4-2 variants, consistent with the known role of this region during spliceosome activation. Finally, we estimate that variants in this 18 base pair region explain 0.4% of individuals with NDD. This work underscores the importance of non-coding genes in rare disorders and will provide a diagnosis to thousands of individuals with NDD worldwide

Rôle des voies de signalisation de deux protéines kinases, Erk et Akt, dans l effet anti-œdémateux de l érythropoïétine

Notre équipe avait montré que l érythropoïétine (EPO) diminuait significativement l œdème cérébral (OC) des rats soumis à un traumatisme crânien diffus (TC). Cette diminution était accompagnée de modifications intracérébrales précoces de phosphorylation des protéines kinases Erk et Akt. Dans cette étude, nous avons tenté de mettre en évidence un lien causal entre les modifications de phosphorylation observées et la diminution de l œdème cérébral, par inhibition de ces protéines kinases. Afin d inhiber Erk et Akt directement en intracérébral, un modèle d injection intracérébroventriculaire a été validé par injection intracérébrale d encre de Chine et visualisation en microscopie optique. L inhibiteur de Erk, U0126 ou d Akt, LY294,002 ont été injectés juste avant le traumatisme crânien. L EPO (5 000 UI/kg) a été administrée par voie intraveineuse 30 minutes après le TC. La phosphorylation des protéines kinases était mesurée à 1 heure (H1) et l œdème cérébral était évalué par gravimétrie à 2 heures (H2). L inhibition de Akt n a pas modifié l OC post-TC et l administration d EPO est demeurée sur l OC. Akt ne semble donc pas jouer de rôle dans l effet anti-œdémateux de l EPO. Après inhibition de Erk, la diminution de l OC a été comparable à celle observée avec l EPO sans effet additif. Ces données suggèrent que l effet anti-œdémateux cérébral de l EPO après TC diffus pourrait être médié par l inhibition précoce de la phosphorylation Erk.Our team found that erythropoietin (EPO) significantly reduced the development of brain edema in a rat model of diffuse traumatic brain injury (TBI). This reduction was associated with early changes of brain phosphorylation of two protein kinases, Erk and Akt. In this study, we investigated the possible causal link between phosphorylation changes and brain edema. To specifically inhibit Erk and Akt, we developed a model with intracerebroventricular injection by using intracerebral injection of Indian ink and optical microscopy visualization. The ERK-1/-2 inhibitor, U0126, or the Akt inhibitor, LY294002 were administered before traumatic brain injury. EPO (5,000 IU/kg body weight) was intravenously administrated 30 mins after injury brain. Phosphorylation of Erk and Akt was measured 1 hour after insult (H1) and brain water content were measured 2 hours (H2) after insult by gravimetric technique. The inhibition of Akt pathway did not result in significant differences in brain water contain (BWC); the addition of post injury treatment with EPO significantly decreased BWC. Inhibition of Erk reduced BWC, no further reduction of brain edema was found when Erk was combined with EPO treatment. These results suggest that the anti-edematous effect of EPO after diffuse TBI could be mediated through an early inhibition of ERK phosphorylation.GRENOBLE1-BU Médecine pharm. (385162101) / SudocSudocFranceF

[Normobaric hyperoxia therapy for patients with traumatic brain injury].

International audienceCerebral ischaemia plays a major role in the outcome of brain-injured patients. Because brain oxygenation can be assessed at bedside using intra-parenchymal devices, there has been a growing interest about whether therapeutic hyperoxia could be beneficial for severely head-injured patients. Normobaric hyperoxia increases brain oxygenation and may improve glucose-lactate metabolism in brain regions at risk for ischaemia. However, benefits of normobaric hyperoxia on neurological outcome are not established yet, that hinders the systematic use of therapeutic hyperoxia in head-injured patients. This therapeutic option might be proposed when brain ischemia persists despite the optimization of cerebral blood flow and arterial oxygen blood content

Reduced brain edema and functional deficits after treatment of diffuse traumatic brain injury by carbamylated erythropoietin derivative.

International audienceOBJECTIVE: To investigate the effects of carbamylated erythropoietin, a modified erythropoietin lacking erythropoietic activity, on brain edema and functional recovery in a model of diffuse traumatic brain injury. DESIGN: Adult male Wistar rats. SETTING: Neurosciences and physiology laboratories. INTERVENTIONS: Thirty minutes after diffuse traumatic brain injury (impact-acceleration model), rats were intravenously administered with either a saline solution (traumatic brain injury-saline) or carbamylated erythropoietin (50 μg/kg; traumatic brain injury-carbamylated erythropoietin). A third group received no traumatic brain injury insult (sham-operated). MEASUREMENTS AND MAIN RESULTS: Three series of experiments were conducted to investigate: 1) the effect of carbamylated erythropoietin on brain edema before and 1 hr after traumatic brain injury using diffusion-weighted magnetic resonance imaging and measurements of apparent diffusion coefficient (n = 10 rats per group), and the phosphorylation level of brain extracellular-regulated kinase-1/-2 was also determined to indicate the presence of an activated cell signaling pathway; 2) the time course of brain edema using magnetic resonance imaging between 4 and 6 hrs postinjury and the gravimetric technique at 6 hrs (n = 10 rats per group); and 3) motor and cognitive function over 10 days post traumatic brain injury, testing acute somatomotor reflexes, adhesive paper removal, and two-way active avoidance (n = 8 rats per group). Compared to traumatic brain injury-saline rats, rats receiving traumatic brain injury-carbamylated erythropoietin showed a significant reduction in brain edema formation at 1 hr that was sustained until 6 hrs when results were comparable with sham-operated rats. This antiedematous effect of carbamylated erythropoietin was possibly mediated through an early inhibition of extracellular-regulated kinase-1/-2 phosphorylation. Compared to traumatic brain injury-saline rats, traumatic brain injury-carbamylated erythropoietin rats showed improved functional recovery of the acute somatomotor reflexes post traumatic brain injury, took less time to remove adhesive from the forelimbs, and showed higher percentages of correct avoidance responses. CONCLUSION: Our findings indicate that early posttraumatic administration of carbamylated erythropoietin reduces brain edema development until at least 6 hrs postinjury and improves neurologic recovery. Carbamylated erythropoietin can thus be considered as a potential agent in the treatment of traumatic brain injury-induced diffuse edema

The impact of erythropoietin on short-term changes in phosphorylation of brain protein kinases in a rat model of traumatic brain injury.

International audienceWe found that recombinant human erythropoietin (rhEPO) reduced significantly the development of brain edema in a rat model of diffuse traumatic brain injury (TBI) (impact-acceleration model). In this study, we investigated the molecular and intracellular changes potentially involved in these immediate effects. Brain tissue nitric oxide (NO) synthesis, phosphorylation level of two protein kinases (extracellular-regulated kinase (ERK)-1/-2 and Akt), and brain water content were measured 1 (H1) and 2 h (H2) after insult. Posttraumatic administration of rhEPO (5,000 IU/kg body weight, intravenously, 30 mins after injury) reduced TBI-induced upregulation of ERK phosphorylation, although it increased Akt phosphorylation at H1. These early molecular changes were associated with a reduction in brain NO synthesis at H1 and with an attenuation of brain edema at H2. Intraventricular administration of the ERK-1/-2 inhibitor, U0126, or the Akt inhibitor, LY294002, before injury showed that ERK was required for brain edema formation, and that rhEPO-induced reduction of edema could involve the ERK pathway. These results were obtained in the absence of any evidence of blood-brain barrier damage on contrast-enhanced magnetic resonance images. The findings of our study indicate that the anti edematous effect of rhEPO could be mediated through an early inhibition of ERK phosphorylation after diffuse TBI

Impact on disease mortality of clinical, biological, and virological characteristics at hospital admission and overtime in COVID‐19 patients

International audienc

De novo variants in the non-coding spliceosomal snRNA gene RNU4-2 are a frequent cause of syndromic neurodevelopmental disorders.

Around 60% of individuals with neurodevelopmental disorders (NDD) remain undiagnosed after comprehensive genetic testing, primarily of protein-coding genes 1 . Increasingly, large genome-sequenced cohorts are improving our ability to discover new diagnoses in the non-coding genome. Here, we identify the non-coding RNA RNU4-2 as a novel syndromic NDD gene. RNU4-2 encodes the U4 small nuclear RNA (snRNA), which is a critical component of the U4/U6.U5 tri-snRNP complex of the major spliceosome 2 . We identify an 18 bp region of RNU4-2 mapping to two structural elements in the U4/U6 snRNA duplex (the T-loop and Stem III) that is severely depleted of variation in the general population, but in which we identify heterozygous variants in 119 individuals with NDD. The vast majority of individuals (77.3%) have the same highly recurrent single base-pair insertion (n.64_65insT). We estimate that variants in this region explain 0.41% of individuals with NDD. We demonstrate that RNU4-2 is highly expressed in the developing human brain, in contrast to its contiguous counterpart RNU4-1 and other U4 homologs, supporting RNU4-2 's role as the primary U4 transcript in the brain. Overall, this work underscores the importance of non-coding genes in rare disorders. It will provide a diagnosis to thousands of individuals with NDD worldwide and pave the way for the development of effective treatments for these individuals. </p

Long-term neurological symptoms after acute COVID-19 illness requiring hospitalization in adult patients: insights from the ISARIC-COVID-19 follow-up study

in this study we aimed to characterize the type and prevalence of neurological symptoms related to neurological long-COVID-19 from a large international multicenter cohort of adults after discharge from hospital for acute COVID-19

De novo variants in the RNU4-2 snRNA cause a frequent neurodevelopmental syndrome

Around 60% of individuals with neurodevelopmental disorders (NDD) remain undiagnosed after comprehensive genetic testing, primarily of protein-coding genes1. Large genome-sequenced cohorts are improving our ability to discover new diagnoses in the non-coding genome. Here, we identify the non-coding RNA RNU4-2 as a syndromic NDD gene. RNU4-2 encodes the U4 small nuclear RNA (snRNA), which is a critical component of the U4/U6.U5 tri-snRNP complex of the major spliceosome2. We identify an 18 bp region of RNU4-2 mapping to two structural elements in the U4/U6 snRNA duplex (the T-loop and Stem III) that is severely depleted of variation in the general population, but in which we identify heterozygous variants in 115 individuals with NDD. Most individuals (77.4%) have the same highly recurrent single base insertion (n.64_65insT). In 54 individuals where it could be determined, the de novo variants were all on the maternal allele. We demonstrate that RNU4-2 is highly expressed in the developing human brain, in contrast to RNU4-1 and other U4 homologs. Using RNA-sequencing, we show how 5' splice site usage is systematically disrupted in individuals with RNU4-2 variants, consistent with the known role of this region during spliceosome activation. Finally, we estimate that variants in this 18 bp region explain 0.4% of individuals with NDD. This work underscores the importance of non-coding genes in rare disorders and will provide a diagnosis to thousands of individuals with NDD worldwide