Monoallelic deletion of the microRNA biogenesis gene Dgcr8 produces deficits in the development of excitatory synaptic transmission in the prefrontal cortex

Abstract Background Neuronal phenotypes associated with hemizygosity of individual genes within the 22q11.2 deletion syndrome locus hold potential towards understanding the pathogenesis of schizophrenia and autism. Included among these genes is Dgcr8, which encodes an RNA-binding protein required for microRNA biogenesis. Dgcr8 haploinsufficient mice (Dgcr8+/-) have reduced expression of microRNAs in brain and display cognitive deficits, but how microRNA deficiency affects the development and function of neurons in the cerebral cortex is not fully understood. Results In this study, we show that Dgcr8+/- mice display reduced expression of a subset of microRNAs in the prefrontal cortex, a deficit that emerges over postnatal development. Layer V pyramidal neurons in the medial prefrontal cortex of Dgcr8+/- mice have altered electrical properties, decreased complexity of basal dendrites, and reduced excitatory synaptic transmission. Conclusions These findings demonstrate that precise microRNA expression is critical for the postnatal development of prefrontal cortical circuitry. Similar defects in neuronal maturation resulting from microRNA deficiency could represent endophenotypes of certain neuropsychiatric diseases of developmental onset

Detection of Multiple Variants of Grapevine Fanleaf Virus in Single Xiphinema index Nematodes

Grapevine fanleaf virus (GFLV) is responsible for a widespread disease in vineyards worldwide. Its genome is composed of two single-stranded positive-sense RNAs, which both show a high genetic diversity. The virus is transmitted from grapevine to grapevine by the ectoparasitic nematode Xiphinema index. Grapevines in diseased vineyards are often infected by multiple genetic variants of GFLV but no information is available on the molecular composition of virus variants retained in X. index following nematodes feeding on roots. In this work, aviruliferous X. index were fed on three naturally GFLV-infected grapevines for which the virome was characterized by RNAseq. Six RNA-1 and four RNA-2 molecules were assembled segregating into four and three distinct phylogenetic clades of RNA-1 and RNA-2, respectively. After 19 months of rearing, single and pools of 30 X. index tested positive for GFLV. Additionally, either pooled or single X. index carried multiple variants of the two GFLV genomic RNAs. However, the full viral genetic diversity found in the leaves of infected grapevines was not detected in viruliferous nematodes, indicating a genetic bottleneck. Our results provide new insights into the complexity of GFLV populations and the putative role of X. index as reservoirs of virus diversity

Nanobody-mediated resistance to grapevine fanleaf virus in plants

Since their discovery, single-domain antigen-binding fragments of camelid-derived heavy-chain-only antibodies, also known as nanobodies (Nbs), have proven to be of outstanding interest as therapeutics against human diseases and pathogens including viruses, but their use against phytopathogens remains limited. Many plant viruses including Grapevine fanleaf virus (GFLV), a nematode-transmitted icosahedral virus and causal agent of fanleaf degenerative disease, have worldwide distribution and huge burden on crop yields representing billions of US dollars of losses annually, yet solutions to combat these viruses are often limited or inefficient. Here, we identified a Nb specific to GFLV that confers strong resistance to GFLV upon stable expression in the model plant Nicotiana benthamiana and also in grapevine rootstock, the natural host of the virus. We showed that resistance was effective against a broad range of GFLV isolates independently of the inoculation method including upon nematode transmission but not against its close relative, Arabis mosaic virus. We also demonstrated that virus neutralization occurs at an early step of the virus life cycle, prior to cell-to-cell movement. Our findings will not only be instrumental to confer resistance to GFLV in grapevine, but more generally they pave the way for the generation of novel antiviral strategies in plants based on Nbs

Extending autologous transplantation as first line therapy in multiple myeloma patients with severe renal impairment: a retrospective study by the SFGM-TC

IF 4.497International audienceRenal impairment is a common complication of multiple myeloma (MM), accounting for 20–30% of MM patients at diagnosis and 40–50% of patients during the course of their disease. This feature is associated with poor prognosis and shorter survival as compared to patients with normal renal function (NRF). Therefore, therapeutic management is challenging as autologous stem cell transplantation (ASCT) is often not considered as a valuable strategy, mainly due to concerns of toxicity. In this retrospective and multicenter study, we included 55 MM patients with dialysis-dependent or independent renal failure who underwent high-dose melphalan-based ASCT in order to assess the efficacy outcomes and toxicities of this strategy. Response to ASCT was at least VGPR (very good PR) in 58% of patients and 96% of patients who also received bortezomib-based induction were at least in PR after ASCT. Median OS was 76 months and median PFS was 55 months, similarly to MM patients with NRF. In multivariate analysis, dose of melphalan (140 mg/m2) was correlated with better PFS (18 months, P = 0.005). Toxicities included febrile neutropenia (75%) and severe mucositis (34%). Overall, this work confirmed that ASCT conditioned by 140 mg/m2 melphalan is a beneficial procedure for MM patients with renal failure