Lipopolysaccharide distinctively alters human microglia transcriptomes to resemble microglia from Alzheimer's disease mouse models.

Alzheimer's disease (AD) is the most common form of dementia, and risk-influencing genetics implicates microglia and neuroimmunity in the pathogenesis of AD. Induced pluripotent stem cell (iPSC)-derived microglia (iPSC-microglia) are increasingly used as a model of AD, but the relevance of historical immune stimuli to model AD is unclear. We performed a detailed cross-comparison over time on the effects of combinatory stimulation of iPSC-microglia, and in particular their relevance to AD. We used single-cell RNA sequencing to measure the transcriptional response of iPSC-microglia after 24 h and 48 h of stimulation with prostaglandin E2 (PGE2) or lipopolysaccharide (LPS)+interferon gamma (IFN-γ), either alone or in combination with ATPγS. We observed a shared core transcriptional response of iPSC-microglia to ATPγS and to LPS+IFN-γ, suggestive of a convergent mechanism of action. Across all conditions, we observed a significant overlap, although directional inconsistency to genes that change their expression levels in human microglia from AD patients. Using a data-led approach, we identify a common axis of transcriptomic change across AD genetic mouse models of microglia and show that only LPS provokes a transcriptional response along this axis in mouse microglia and LPS+IFN-γ in human iPSC-microglia. This article has an associated First Person interview with the first author of the paper.

Negative Pressure Wound Therapy in Postbariatric Lower Body Lift-A Method of Decreasing Postoperative Complications.

BACKGROUND: Lower body lift procedure is one of the most common procedures in postbariatric surgery, which can be followed by postoperative complications that delay the healing time. The purpose of this study was to analyse whether the use of negative pressure wound therapy (NPWT) as a replacement for the classical drainage method would provide better postoperative results with fewer complications. METHODS: The authors reviewed their experience with 46 consecutive patients that underwent lower body lift surgery from 2018 to 2021. They were divided into two groups: 23 of them received NPWT as drainage method and another 23 received classical active drains. We assessed the complication rates and types between the two groups to demonstrate the efficiency of NPWT as a support in the surgical protocol. RESULTS: Forty-six patients were included in this study. Two equal groups formed by 23 patients were analysed for age, sex, type of weight loss, type of circumferential lower body lift, type of drainage, quantity of drainage, time of drain usance, postoperative complications, operation time, hospital stay and frequency of hospital visits. The group that received NPWT had a 26.08% rate of complications as compared with the drain group that had a 47.8% complication rate. CONCLUSIONS: This study is performed as a comparison between negative pressure wound therapy and classical drainage method in lower body lift surgery, as a new method of reducing the postoperative complications. By achieving faster closure of large, undermining areas, it concludes in a lower risk of seroma or hematoma formation. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Post-traumatic stress disorder following childbirth.

BACKGROUND: Childbirth experience could be complicated and even traumatic. This study explored the possible risk factors for post-traumatic stress disorder following childbirth (PTSD-FC) in mothers and partners. METHODS: Through a cross-sectional online survey biographical, medical, psychological, obstetrical and trauma history data were collected. The PTSD-FC, postnatal depression, social support, and perceived mother-infant bond in 916 mothers and 64 partners were measured through self-reported psychometric assessments. RESULTS: Our findings highlight the possible impact of several risk factors such as emergency childbirth, past traumatic experiences and distressing events during childbirth on PTSD-FC. The difficulties in mother-infant bond and the postpartum depression were highly associated with the total score of PTSD-FC symptoms for mothers. While for partners, post-partum depression was highly associated with the total score of PTSD-FC. CONCLUSIONS: Our study demonstrated significant links between psychological, traumatic and birth-related risk factors as well as the perceived social support and the possible PTSD following childbirth in mothers and partners. Given that, a specific attention to PTSD-FC and psychological distress following childbirth should be given to mothers and their partners following childbirth.

Maturation of the 90S pre-ribosome requires Mrd1 dependent U3 snoRNA and 35S pre-rRNA structural rearrangements.

In eukaryotes, ribosome biogenesis requires folding and assembly of the precursor rRNA (pre-rRNA) with a large number of proteins and snoRNPs into huge RNA-protein complexes. In spite of intense genetic, biochemical and high-resolution cryo-EM studies in Saccharomyces cerevisiae, information about the structure of the 35S pre-rRNA is limited. To overcome this, we performed high-throughput SHAPE chemical probing on the 35S pre-rRNA within 90S pre-ribosomes. We focused our analyses on external (5'ETS) and internal (ITS1) transcribed spacers as well as the 18S rRNA region. We show that in the 35S pre-rRNA, the central pseudoknot is not formed and the central core of the 18S rRNA is in an open configuration but becomes more constrained in 20S pre-rRNA. The essential ribosome biogenesis protein Mrd1 influences the structure of the 18S rRNA region locally and is involved in organizing the central pseudoknot and surrounding structures. We demonstrate that U3 snoRNA dynamically interacts with the 35S pre-rRNA and that Mrd1 is required for disrupting U3 snoRNA base pairing interactions in the 5'ETS. We propose that the dynamic U3 snoRNA interactions and Mrd1 are essential for establishing the structure of the central core of 18S rRNA that is required for processing and 40S subunit function.

High-throughput RNA structure probing reveals critical folding events during early 60S ribosome assembly in yeast.

While the protein composition of various yeast 60S ribosomal subunit assembly intermediates has been studied in detail, little is known about ribosomal RNA (rRNA) structural rearrangements that take place during early 60S assembly steps. Using a high-throughput RNA structure probing method, we provide nucleotide resolution insights into rRNA structural rearrangements during nucleolar 60S assembly. Our results suggest that many rRNA-folding steps, such as folding of 5.8S rRNA, occur at a very specific stage of assembly, and propose that downstream nuclear assembly events can only continue once 5.8S folding has been completed. Our maps of nucleotide flexibility enable making predictions about the establishment of protein-rRNA interactions, providing intriguing insights into the temporal order of protein-rRNA as well as long-range inter-domain rRNA interactions. These data argue that many distant domains in the rRNA can assemble simultaneously during early 60S assembly and underscore the enormous complexity of 60S synthesis.Ribosome biogenesis is a dynamic process that involves the ordered assembly of ribosomal proteins and numerous RNA structural rearrangements. Here the authors apply ChemModSeq, a high-throughput RNA structure probing method, to quantitatively measure changes in RNA flexibility during the nucleolar stages of 60S assembly in yeast.

Snapshots of pre-rRNA structural flexibility reveal eukaryotic 40S assembly dynamics at nucleotide resolution.

Ribosome assembly in eukaryotes involves the activity of hundreds of assembly factors that direct the hierarchical assembly of ribosomal proteins and numerous ribosomal RNA folding steps. However, detailed insights into the function of assembly factors and ribosomal RNA folding events are lacking. To address this, we have developed ChemModSeq, a method that combines structure probing, high-throughput sequencing and statistical modeling, to quantitatively measure RNA structural rearrangements during the assembly of macromolecular complexes. By applying ChemModSeq to purified 40S assembly intermediates we obtained nucleotide-resolution maps of ribosomal RNA flexibility revealing structurally distinct assembly intermediates and mechanistic insights into assembly dynamics not readily observed in cryo-electron microscopy reconstructions. We show that RNA restructuring events coincide with the release of assembly factors and predict that completion of the head domain is required before the Rio1 kinase enters the assembly pathway. Collectively, our results suggest that 40S assembly factors regulate the timely incorporation of ribosomal proteins by delaying specific folding steps in the 3' major domain of the 20S pre-ribosomal RNA.