γδ T cell profiling in a cohort of preterm infants reveals elevated frequencies of CD83+ γδ T cells in sepsis.

Preterm infants are at high risk of developing neonatal sepsis. γδ T cells are thought to be an important set of effector cells in neonates. Here, γδ T cells were investigated in a longitudinal cohort of preterm neonates using next-generation sequencing, flow cytometry, and functional assays. During the first year of life, the Vγ9Vδ2 T cell subset showed dynamic phenotypic changes and elevated levels of fetal-derived Vγ9Vδ2 T cells were evident in infants with sepsis. Single-cell transcriptomics identified HLA-DRhiCD83+ γδ T cells in neonatal sepsis, which expressed genes related to antigen presentation. In vitro assays showed that CD83 was expressed on activated Vγ9Vδ2 T cells in preterm and term neonates, but not in adults. In contrast, activation of adult Vγ9Vδ2 T cells enhanced CD86 expression, which was presumably the key receptor to induce CD4 T cell proliferation. Together, we provide a map of the maturation of γδ T cells after preterm birth and highlight their phenotypic diversity in infections.

Evolution of Fetal Growth in Symptomatic Sars-Cov-2 Pregnancies.

INTRODUCTION: SARS-CoV-2 is a viral disease with potentially devastating effects. Observational studies of pregnant women infected with SARS-CoV-2 report an increased risk for FGR. This study utilizes data from a prospective SARS-CoV-2 registry in pregnancy, investigating the progression of fetuses to fetal growth restriction (FGR) at birth following maternal SARS-CoV-2 and evaluating the hypothesis of whether the percentage of SGA at birth is increased after maternal SARS-CoV-2 taking into account the time interval between infection and birth. MATERIALS & METHODS: CRONOS is a prospective German registry enrolling pregnant women with confirmed SARS-CoV-2 infection during their pregnancy. SARS-CoV-2 symptoms, pregnancy- and delivery-specific information were recorded. The data evaluated in this study range from March 2020 until August 2021. Women with SARS-CoV-2 were divided into three groups according to the time of infection/symptoms to delivery: Group I<2 weeks, Group II 2-4 weeks, and Group III>4 weeks. FGR was defined as estimated and/or birth weight<10% ile, appropriate for gestational age (AGA) was within 10 and 90%ile, and large for gestational age (LGA) was defined as fetal or neonatal weight>90%ile. RESULTS: Data for a total of 2,650 SARS-CoV-2-positive pregnant women were available. The analysis was restricted to symptomatic cases that delivered after 24+0 weeks of gestation. Excluding those cases with missing values for estimated fetal weight at time of infection and/or birth weight centile, 900 datasets remained for analyses. Group I consisted of 551 women, Group II of 112 women, and Group III of 237 women. The percentage of changes from AGA to FGR did not differ between groups. However, there was a significantly higher rate of large for gestational age (LGA) newborns at the time of birth compared to the time of SARS-CoV-2 infection in Group III (p=0.0024), respectively. CONCLUSION: FGR rates did not differ between symptomatic COVID infections occurring within 2 weeks and>4 weeks before birth. On the contrary, it presented a significant increase in LGA pregnancies in Group III. However, in this study population, an increase in the percentage of LGA may be attributed to pandemic measures and a reduction in daily activity.

[COVID-19 in Pregnancy - a Risk for the Unborn Child?] / COVID-19 in der Schwangerschaft: Ursache für eine intrakranielle Blutung bei einem Frühgeborenen?

Geburtskliniken werden zunehmend mit an Covid-19 erkrankten Schwangeren konfrontiert. Dies stellt Geburtshelfer vor große Herausforderungen, da einige Fragestellungen noch nicht ausreichend wissenschaftlich erforscht sind. Über Covid-19 während der Schwangerschaft und seine Auswirkungen auf das ungeborene und neugeborene Kind ist nicht viel bekannt.

Impairment of the neurotrophic signaling hub B-Raf contributes to motoneuron degeneration in spinal muscular atrophy.

Spinal muscular atrophy (SMA) is a motoneuron disease caused by deletions of the Survival of Motoneuron 1 gene (SMN1) and low SMN protein levels. SMN restoration is the concept behind a number of recently approved drugs which result in impressive yet limited effects. Since SMN has already been enhanced in treated patients, complementary SMN-independent approaches are needed. Previously, a number of altered signaling pathways which regulate motoneuron degeneration have been identified as candidate targets. However, signaling pathways form networks, and their connectivity is still unknown in SMA. Here, we used presymptomatic SMA mice to elucidate the network of altered signaling in SMA. The SMA network is structured in two clusters with AKT and 14-3-3 ζ/δ in their centers. Both clusters are connected by B-Raf as a major signaling hub. The direct interaction of B-Raf with 14-3-3 ζ/δ is important for an efficient neurotrophic activation of the MEK/ERK pathway and crucial for motoneuron survival. Further analyses in SMA mice revealed that both proteins were down-regulated in motoneurons and the spinal cord with B-Raf being reduced at presymptomatic stages. Primary fibroblasts and iPSC-derived motoneurons from SMA patients both showed the same pattern of down-regulation. This mechanism is conserved across species since a Caenorhabditis elegans SMA model showed less expression of the B-Raf homolog lin-45 Accordingly, motoneuron survival was rescued by a cell autonomous lin-45 expression in a C. elegans SMA model resulting in improved motor functions. This rescue was effective even after the onset of motoneuron degeneration and mediated by the MEK/ERK pathway.