Biology subjects

Lutservitz, A.

Publications and source records attributed to Lutservitz, A..

5 recordsLinked to original sources

bioRxiv2024

Concerted neuron-astrocyte gene expression declines in aging and schizophrenia

Human brains vary across people and over time; such variation is not yet understood in cellular terms. Here we describe a striking relationship between peoples cortical neurons and cortical astrocytes. We used single-nucleus RNA-seq to analyze the prefrontal cortex of 191 human donors ages 22-97 years, including healthy individuals and persons with schizophrenia. Latent-factor analysis of these data revealed that in persons whose cortical neurons more strongly expressed genes for synaptic components, cortical astrocytes more strongly expressed distinct genes with synaptic functions and genes for synthesizing cholesterol, an astrocyte-supplied component of synaptic membranes. We call this relationship the Synaptic Neuron- and-Astrocyte Program (SNAP). In schizophrenia and aging - two conditions that involve declines in cognitive flexibility and plasticity 1,2 - cells had divested from SNAP: astrocytes, glutamatergic (excitatory) neurons, and GABAergic (inhibitory) neurons all reduced SNAP expression to corresponding degrees. The distinct astrocytic and neuronal components of SNAP both involved genes in which genetic risk factors for schizophrenia were strongly concentrated. SNAP, which varies quantitatively even among healthy persons of similar age, may underlie many aspects of normal human interindividual differences and be an important point of convergence for multiple kinds of pathophysiology.

neuroscience↗

bioRxiv2023

Sibling chimerism among microglia in marmosets

Chimerism happens rarely among most mammals but is common in marmosets and tamarins, a result of fraternal twin or triplet birth patterns in which in utero connected circulatory systems (through which stem cells transit) lead to persistent blood chimerism (12-80%) throughout life. The presence of Y-chromosome DNA sequences in organs of female marmosets has long suggested that chimerism might also affect these organs. However, a longstanding question is whether this chimerism is driven by blood-derived cells or involves contributions from other cell types. To address this question, we analyzed single-cell RNA-seq data from blood, liver, kidney and many brain regions across a number of marmosets, using transcribed single nucleotide polymorphisms (SNPs) to identify cells with the siblings genome in various cell types within these tissues. Sibling-derived chimerism in all tissues arose entirely from cells of hematopoietic origin (i.e., myeloid and lymphoid lineages). In brain tissue this was reflected as sibling-derived chimerism among microglia (20-52%) and macrophages (18-64%) but not among other resident cell types (neurons, glia or ependymal cells). The percentage of microglia that were sibling-derived showed significant variation across brain regions, even within individual animals, likely reflecting distinct responses by genetic-sibling microglia to local recruitment or proliferation cues or, potentially, distinct clonal expansion histories in different brain areas. In the animals and tissues we analyzed, microglial gene expression profiles bore a much stronger relationship to local/host context than to sibling genetic differences. Naturally occurring marmoset chimerism will provide new ways to recognize the effects of genes, mutations and brain contexts on microglial biology and to distinguish between effects of microglia and other cell types on brain phenotypes.

neuroscience↗

bioRxiv2022

A marmoset brain cell census reveals persistent influence of developmental origin on neurons

The mammalian brain is composed of many brain structures, each with its own ontogenetic and developmental history. Transcriptionally-based cell type taxonomies reveal cell type composition and similarity relationships within and across brain structures. We sampled over 2.4 million brain cells across 18 locations in the common marmoset, a New World monkey primed for genetic engineering, and used single-nucleus RNA sequencing to examine global gene expression patterns of cell types within and across brain structures. Our results indicate that there is generally a high degree of transcriptional similarity between GABAergic and glutamatergic neurons found in the same brain structure, and there are generally few shared molecular features between neurons that utilize the same neurotransmitter but reside in different brain structures. We also show that in many cases the transcriptional identities of cells are intrinsically retained from their birthplaces, even when they migrate beyond their cephalic compartments. Thus, the adult transcriptomic identity of most neuronal types appears to be shaped much more by their developmental identity than by their primary neurotransmitter signaling repertoire. Using quantitative mapping of single molecule FISH (smFISH) for markers for GABAergic interneurons, we found that the similar types (e.g. PVALB+ interneurons) have distinct biodistributions in the striatum and neocortex. Interneuron types follow medio-lateral gradients in striatum but form complex distributions across the neocortex that are not described by simple gradients. Lateral prefrontal areas in marmoset are distinguished by high relative proportions of VIP+ neurons. We further used cell-type-specific enhancer driven AAV-GFP to visualize the morphology of molecularly-resolved interneuron classes in neocortex and striatum, including the previously discovered novel primate-specific TAC3+ striatal interneurons. Our comprehensive analyses highlight how lineage and functional class contribute to the transcriptional identity and biodistribution of primate brain cell types. One-Sentence SummaryAdult primate neurons are imprinted by their region of origin, more so than by their functional identity.

neuroscience↗

bioRxiv2019

Hedgehog signaling regulates neurogenesis in the larval and adult zebrafish hypothalamus

While neurogenesis in the adult hypothalamus is now known to be essential for proper function, the cell-cell signaling events that regulate neurogenesis in this evolutionarily conserved brain region remain poorly understood. Here we show that Hedgehog (Hh)/Gli signaling positively regulates hypothalamic neurogenesis in both larval and adult zebrafish and is necessary and sufficient for normal hypothalamic proliferation rates. Hedgehog-responsive cells are relatively rapidly proliferating pluripotent neural precursors that give rise to dopaminergic, serotonergic, and GABAergic neurons. in situ and transgenic reporter analyses revealed substantial heterogeneity in cell-cell signaling within the hypothalamic niche, with slow cycling Nestin-expressing cells residing among distinct and overlapping populations of Sonic Hh (Shh)-expressing, Hh-responsive, Notch-responsive, and Wnt-responsive radial glia. This work shows for the first time that Hh/Gli-signaling is a key component of the complex cell-cell signaling environment that regulates hypothalamic neurogenesis throughout life.

neuroscience↗

bioRxiv2019

Innovations in Primate Interneuron Repertoire

Primates and rodents, which descended from a common ancestor more than 90 million years ago, exhibit profound differences in behavior and cognitive capacity. Modifications, specializations, and innovations to brain cell types may have occurred along each lineage. We used Drop-seq to profile RNA expression in more than 184,000 individual telencephalic interneurons from humans, macaques, marmosets, and mice. Conserved interneuron types varied significantly in abundance and RNA expression between mice and primates, but varied much more modestly among primates. In adult primates, the expression patterns of dozens of genes exhibited spatial expression gradients among neocortical interneurons, suggesting that adult neocortical interneurons are imprinted by their local cortical context. In addition, we found that an interneuron type previously associated with the mouse hippocampus--the \"ivy cell\", which has neurogliaform characteristics--has become abundant across the neocortex of humans, macaques, and marmosets. The most striking innovation was subcortical: we identified an abundant striatal interneuron type in primates that had no molecularly homologous cell population in mouse striatum, cortex, thalamus, or hippocampus. These interneurons, which expressed a unique combination of transcription factors, receptors, and neuropeptides, including the neuropeptide TAC3, constituted almost 30% of striatal interneurons in marmosets and humans. Understanding how gene and cell-type attributes changed or persisted over the evolutionary divergence of primates and rodents will guide the choice of models for human brain disorders and mutations and help to identify the cellular substrates of expanded cognition in humans and other primates.

neuroscience↗