Probes for INS

Vascular dementia (VaD) is cognitive decline linked to reduced cerebral blood perfusion, yet there are few therapeutic options to protect cognitive function following cerebrovascular accidents. The purpose of this study was to profile gene expression changes unique to VaD to identify and characterize disease relevant changes that could offer clues for future therapeutic direction. Microarray-based profiling and validation studies of postmortem frontal cortex samples from VaD, Alzheimer disease, and age-matched control subjects revealed that the oxytocin receptor (OXTR) was strongly and differentially upregulated in VaD. Further characterization in fixed tissue from the same cases showed that OXTR upregulation occurs de novo around and within microinfarcts in peri-infarct reactive astrocytes as well as within vascular profiles, likely on microvascular endothelial cells. These results indicate that increased OXTR expression in peri-infarct regions may be a specific response to microvascular insults. Given the established OXTR signaling cascades that elicit antioxidant, anti-inflammatory, and pro-angiogenic responses, the present findings suggest that de novo OXTR expression in the peri-infarct space is a tissue-protective response by astroglial and vascular cells in the wake of ischemic damage that could be exploited as a therapeutic option for the preservation of cognition following cerebrovascular insults.

Alzheimer's disease (AD) is a pervasive neurodegenerative disorder, the molecular and cellular complexity of which remains poorly understood. Here, we profiled and analysed 80,660 single-nucleus transcriptomes from prefrontal cortex of 48 individuals with varying degrees of AD pathology. We identified transcriptionally-distinct subpopulations across six major brain cell-types, including those associated with pathology and characterized by regulators of myelination, inflammation, and neuron survival. The strongest AD-associated changes appeared early in pathological progression and were highly cell-type-specific, whereas genes upregulated in late-stage were common across cell types and primarily involved in global stress response. Surprisingly, we found an overrepresentation of female cells in AD-associated subpopulations, and substantially different transcriptional responses between sexes in multiple cell types, including oligodendrocytes. Overall, myelination-related processes were recurrently perturbed in multiple cell types, suggesting a key role in AD pathophysiology. Our single-celltranscriptomic resource provides a first blueprint for interrogating the molecular underpinnings and cellular basis of AD.

Abstract

Shank2 is an abundant postsynaptic scaffolding protein implicated in neurodevelopmental and psychiatric disorders, including autism spectrum disorders (ASD). Deletion of Shank2 in mice has been shown to induce social deficits, repetitive behaviors, and hyperactivity, but the identity of the cell types that contribute to these phenotypes has remained unclear. Here, we report a conditional mouse line with a Shank2 deletion restricted to parvalbumin (PV)-positive neurons (Pv-Cre;Shank2fl/fl mice). These mice display moderate hyperactivity in both novel and familiar environments and enhanced self-grooming in novel, but not familiar, environments. In contrast, they showed normal levels of social interaction, anxiety-like behavior, and learning and memory. Basal brain rhythms in Pv-Cre;Shank2fl/fl mice, measured by electroencephalography, were normal, but susceptibility to pentylenetetrazole (PTZ)-induced seizures was decreased. These results suggest that Shank2 deletion in PV-positive neurons leads to hyperactivity, enhanced self-grooming and suppressed brain excitation.

RNA abundance is a powerful indicator of the state of individual cells. Single-cell RNA sequencing can reveal RNA abundance with high quantitative accuracy, sensitivity and throughput1. However, this approach captures only a static snapshot at a point in time, posing a challenge for the analysis of time-resolved phenomena such as embryogenesis or tissue regeneration. Here we show that RNA velocity-the time derivative of the gene expression state-can be directly estimated by distinguishing between unspliced and spliced mRNAs in common single-cell RNA sequencing protocols. RNA velocity is a high-dimensional vector that predicts the future state of individual cells on a timescale of hours. We validate its accuracy in the neural crest lineage, demonstrate its use on multiple published datasets and technical platforms, reveal the branching lineage tree of the developing mouse hippocampus, and examine the kinetics of transcription in human embryonic brain. We expect RNA velocity to greatly aid the analysis of developmental lineages and cellular dynamics, particularly in humans.