Filbin MG, Tirosh I, Hovestadt V, Shaw ML, Escalante LE, Mathewson ND, Neftel C, Frank N, Pelton K, Hebert CM, Haberler C, Yizhak K, Gojo J, Egervari K, Mount C, van Galen P, Bonal DM, Nguyen QD, Beck A, Sinai C, Czech T, Dorfer C, Goumnerova L, Lavarino
PMID: 29674595 | DOI: 10.1126/science.aao4750
Gliomas with histone H3 lysine27-to-methionine mutations (H3K27M-glioma) arise primarily in the midline of the central nervous system of young children, suggesting a cooperation between genetics and cellular context in tumorigenesis. Although the genetics of H3K27M-glioma are well characterized, their cellular architecture remains uncharted. We performed single-cell RNA sequencing in 3321 cells from six primary H3K27M-glioma and matched models. We found that H3K27M-glioma primarily contain cells that resemble oligodendrocyte precursor cells (OPC-like), whereas more differentiated malignant cells are a minority. OPC-like cells exhibit greater proliferation and tumor-propagating potential than their more differentiated counterparts and are at least in part sustained by PDGFRA signaling. Our study characterizes oncogenic and developmental programs in H3K27M-glioma at single-cell resolution and across genetic subclones, suggesting potential therapeutic targets in this disease.
Cell Rep. 2018 Dec 18;25(12):3435-3450.e6.
Wang J, Saraswat D, Sinha AK, Polanco J, Dietz K, O'Bara MA, Pol SU, Shayya HJ, Sim FJ.
PMID: 30566868 | DOI: 10.1016/j.celrep.2018.11.068
Human oligodendrocyte progenitor cells (hOPCs) persist into adulthood as an abundant precursor population capable of division and differentiation. The transcriptional mechanisms that regulate hOPC homeostasis remain poorly defined. Herein, we identify paired related homeobox protein 1 (PRRX1) in primary PDGFαR+ hOPCs. We show that enforced PRRX1 expression results in reversible G1/0 arrest. While both PRRX1 splice variants reduce hOPC proliferation, only PRRX1a abrogates migration. hOPC engraftment into hypomyelinated shiverer/rag2 mouse brain is severely impaired by PRRX1a, characterized by reduced cell proliferation and migration. PRRX1 induces a gene expression signature characteristic of stem cell quiescence. Both IFN-γ and BMP signaling upregulate PRRX1 and induce quiescence. PRRX1 knockdown modulates IFN-γ-induced quiescence. In mouse brain, PRRX1 mRNA was detected in non-dividing OPCs and is upregulated in OPCs following demyelination. Together, these data identify PRRX1 as a regulator of quiescence in hOPCs and as a potential regulator of pathological quiescence.
Dada, LA;Welch, LC;Magnani, ND;Ren, Z;Han, H;Brazee, PL;Celli, D;Flozak, AS;Weng, A;Herrerias, MM;Kryvenko, V;Vadász, I;Runyan, CE;Abdala-Valencia, H;Shigemura, M;Casalino-Matsuda, SM;Misharin, AV;Budinger, GRS;Gottardi, CJ;Sznajder, JI;
PMID: 36626234 | DOI: 10.1172/jci.insight.159331
Persistent symptoms and radiographic abnormalities suggestive of failed lung repair are among the most common symptoms in patients with COVID-19 after hospital discharge. In mechanically ventilated patients with ARDS secondary to SARS-CoV-2 pneumonia, low tidal volumes to reduce ventilator-induced lung injury necessarily elevate blood CO2 levels, often leading to hypercapnia. The role of hypercapnia on lung repair after injury is not completely understood. Here, using a mouse model of hypercapnia exposure, cell lineage-tracing, spatial transcriptomics and 3D-cultures, we show that hypercapnia limits β-catenin signaling in AT2 cells, leading to their reduced proliferative capacity. Hypercapnia alters expression of major Wnts in PDGFRα+-fibroblasts from those maintaining AT2 progenitor activity towards those that antagonize β-catenin signaling thereby limiting progenitor function. Constitutive activation of β-catenin signaling in AT2 cells or treatment of organoid cultures with recombinant WNT3A protein bypasses the inhibitory effects of hypercapnia. Inhibition of AT2 proliferation in hypercapnic patients may contribute to impaired lung repair after injury, preventing sealing of the epithelial barrier, increasing lung flooding, ventilator dependency and mortality. .
Ichihara, R;Shiraki, Y;Mizutani, Y;Iida, T;Miyai, Y;Esaki, N;Kato, A;Mii, S;Ando, R;Hayashi, M;Takami, H;Fujii, T;Takahashi, M;Enomoto, A;
PMID: 35020975 | DOI: 10.1111/pin.13198
Cancer-associated fibroblasts (CAFs), a compartment of the tumor microenvironment, were previously thought to be a uniform cell population that promotes cancer progression. However, recent studies have shown that CAFs are heterogeneous and that there are at least two types of CAFs, that is, cancer-promoting and -restraining CAFs. We previously identified Meflin as a candidate marker of cancer-restraining CAFs (rCAFs) in pancreatic ductal adenocarcinoma (PDAC). The precise nature of rCAFs, however, has remained elusive owing to a lack of understanding of their comprehensive gene signatures. Here, we screened genes whose expression correlated with Meflin in single-cell transcriptomic analyses of human cancers. Among the identified genes, we identified matrix remodeling-associated protein 8 (MXRA8), which encodes a type I transmembrane protein with unknown molecular function. Analysis of MXRA8 expression in human PDAC samples showed that MXRA8 was differentially co-expressed with other CAF markers. Moreover, in patients with PDAC or syngeneic tumors developed in MXRA8-knockout mice, MXRA8 expression did not affect the roles of CAFs in cancer progression, and the biological importance of MXRA8+ CAFs is still unclear. Overall, we identified MXRA8 as a new CAF marker; further studies are needed to determine the relevance of this marker.
van Bruggen, D;Pohl, F;Langseth, CM;Kukanja, P;Lee, H;Albiach, AM;Kabbe, M;Meijer, M;Linnarsson, S;Hilscher, MM;Nilsson, M;Sundström, E;Castelo-Branco, G;
PMID: 35523173 | DOI: 10.1016/j.devcel.2022.04.016
Oligodendrogenesis in the human central nervous system has been observed mainly at the second trimester of gestation, a much later developmental stage compared to oligodendrogenesis in mice. Here, we characterize the transcriptomic neural diversity in the human forebrain at post-conception weeks (PCW) 8-10. Using single-cell RNA sequencing, we find evidence of the emergence of a first wave of oligodendrocyte lineage cells as early as PCW 8, which we also confirm at the epigenomic level through the use of single-cell ATAC-seq. Using regulatory network inference, we predict key transcriptional events leading to the specification of oligodendrocyte precursor cells (OPCs). Moreover, by profiling the spatial expression of 50 key genes through the use of in situ sequencing (ISS), we identify regions in the human ventral fetal forebrain where oligodendrogenesis first occurs. Our results indicate evolutionary conservation of the first wave of oligodendrogenesis between mice and humans and describe regulatory mechanisms involved in human OPC specification.
Animals : an open access journal from MDPI
Verdile, N;Pasquariello, R;Cardinaletti, G;Tibaldi, E;Brevini, TAL;Gandolfi, F;
PMID: 35011180 | DOI: 10.3390/ani12010074
In order to improve the sustainability of trout farming, it is essential to develop alternatives to fish-based meals that prevent intestinal disorders and support growth performances. Therefore, an accurate knowledge of intestinal morphology and physiology is desirable. We previously described the epithelial component of the intestinal stem-cell (ISC) niche in rainbow trout (Oncorhynchus mykiss), which is one of the most successfully farmed species and a representative model of the salmonids family. This work aims to expand that knowledge by investigating the niche stromal components that contribute to intestinal homeostasis. We analyzed samples belonging to five individuals collected from a local commercial farm. Histological and ultrastructural studies revealed peculiar mesenchymal cells adjacent to the epithelium that generated an intricate mesh spanning from the folds' base to their apex. Their voluminous nuclei, limited cytoplasm and long cytoplasmic projections characterized them as telocytes (TCs). TEM analysis showed the secretion of extracellular vesicles, suggesting their functional implication in cell-to-cell communication. Furthermore, we evaluated the localization of well-defined mouse TC markers (pdgfrα and foxl1) and their relationship with the epithelial component of the niche. TCs establish a direct connection with ISCs and provide short-range signaling, which also indicates their key role as the mesenchymal component of the stem-cell niche in this species. Interestingly, the TC distribution and gene-expression pattern in rainbow trout closely overlapped with those observed in mice, indicating that they have the same functions in both species. These results substantially improve our understanding of the mechanisms regulating intestinal homeostasis and will enable a more detailed evaluation of innovative feed effects.
Matson, KJE;Russ, DE;Kathe, C;Hua, I;Maric, D;Ding, Y;Krynitsky, J;Pursley, R;Sathyamurthy, A;Squair, JW;Levi, BP;Courtine, G;Levine, AJ;
PMID: 36163250 | DOI: 10.1038/s41467-022-33184-1
After spinal cord injury, tissue distal to the lesion contains undamaged cells that could support or augment recovery. Targeting these cells requires a clearer understanding of their injury responses and capacity for repair. Here, we use single nucleus RNA sequencing to profile how each cell type in the lumbar spinal cord changes after a thoracic injury in mice. We present an atlas of these dynamic responses across dozens of cell types in the acute, subacute, and chronically injured spinal cord. Using this resource, we find rare spinal neurons that express a signature of regeneration in response to injury, including a major population that represent spinocerebellar projection neurons. We characterize these cells anatomically and observed axonal sparing, outgrowth, and remodeling in the spinal cord and cerebellum. Together, this work provides a key resource for studying cellular responses to injury and uncovers the spontaneous plasticity of spinocerebellar neurons, uncovering a potential candidate for targeted therapy.
Paeger L, Karakasilioti I, Altmüller J, Frommolt P, Brüning J, Kloppenburg P.
PMID: 28632132 | DOI: 10.7554/eLife.25770
In the arcuate nucleus of the hypothalamus (ARH) satiety signaling (anorexigenic) pro-opiomelanocortin (POMC)-expressing and hunger signaling (orexigenic) agouti-related peptide (AgRP)-expressing neurons are key components of the neuronal circuits that control food intake and energy homeostasis. Here, we assessed whether the catecholamine noradrenalin directly modulates the activity of these neurons in mice. Perforated patch clamp recordings showed that noradrenalin changes the activity of these functionally antagonistic neurons in opposite ways, increasing the activity of the orexigenic NPY/AgRP neurons and decreasing the activity of the anorexigenic POMC neurons. Cell type-specific transcriptomics and pharmacological experiments revealed that the opposing effect on these neurons is mediated by the activation of excitatory α1A - and β- adrenergic receptors in NPY/AgRP neurons, while POMC neurons are inhibited via α2A - adrenergic receptors. Thus, the coordinated differential modulation of the key hypothalamic neurons in control of energy homeostasis assigns noradrenalin an important role to promote feeding.
Tokarska, A;Silberberg, G;
PMID: 35613598 | DOI: 10.1016/j.celrep.2022.110842
The interactions between the striatal cholinergic and GABAergic systems are crucial in shaping reward-related behavior and reinforcement learning; however, the synaptic pathways mediating them are largely unknown. Here, we use Chrna2-Cre mice to characterize striatal interneurons (INs) expressing the nicotinic α2 receptor subunit. Using triple patch-clamp recordings combined with optogenetic stimulations, we characterize the electrophysiological, morphological, and synaptic properties of striatal Chrna2-INs. Striatal Chrna2-INs have diverse electrophysiological properties, distinct from their counterparts in other brain regions, including the hippocampus and neocortex. Unlike in other regions, most striatal Chrna2-INs are fast-spiking INs expressing parvalbumin. Striatal Chrna2-INs are intricately integrated in the striatal microcircuit, forming inhibitory synaptic connections with striatal projection neurons and INs, including other Chrna2-INs. They receive excitatory inputs from primary motor cortex mediated by both AMPA and NMDA receptors. A subpopulation of Chrna2-INs responds to nicotinic input, suggesting reciprocal interactions between this GABAergic interneuron population and striatal cholinergic synapses.
Science translational medicine
Ko, KI;Merlet, JJ;DerGarabedian, BP;Zhen, H;Suzuki-Horiuchi, Y;Hedberg, ML;Hu, E;Nguyen, AT;Prouty, S;Alawi, F;Walsh, MC;Choi, Y;Millar, SE;Cliff, A;Romero, J;Garvin, MR;Seykora, JT;Jacobson, D;Graves, DT;
PMID: 35108061 | DOI: 10.1126/scitranslmed.abj0324
Skin is composed of diverse cell populations that cooperatively maintain homeostasis. Up-regulation of the nuclear factor κB (NF-κB) pathway may lead to the development of chronic inflammatory disorders of the skin, but its role during the early events remains unclear. Through analysis of single-cell RNA sequencing data via iterative random forest leave one out prediction, an explainable artificial intelligence method, we identified an immunoregulatory role for a unique paired related homeobox-1 (Prx1)+ fibroblast subpopulation. Disruption of Ikkb-NF-κB under homeostatic conditions in these fibroblasts paradoxically induced skin inflammation due to the overexpression of C-C motif chemokine ligand 11 (CCL11; or eotaxin-1) characterized by eosinophil infiltration and a subsequent TH2 immune response. Because the inflammatory phenotype resembled that seen in human atopic dermatitis (AD), we examined human AD skin samples and found that human AD fibroblasts also overexpressed CCL11 and that perturbation of Ikkb-NF-κB in primary human dermal fibroblasts up-regulated CCL11. Monoclonal antibody treatment against CCL11 was effective in reducing the eosinophilia and TH2 inflammation in a mouse model. Together, the murine model and human AD specimens point to dysregulated Prx1+ fibroblasts as a previously unrecognized etiologic factor that may contribute to the pathogenesis of AD and suggest that targeting CCL11 may be a way to treat AD-like skin lesions.
Nutritional regulation of oligodendrocyte differentiation regulates perineuronal net remodeling in the median eminence
Kohnke, S;Buller, S;Nuzzaci, D;Ridley, K;Lam, B;Pivonkova, H;Bentsen, MA;Alonge, KM;Zhao, C;Tadross, J;Holmqvist, S;Shimizo, T;Hathaway, H;Li, H;Macklin, W;Schwartz, MW;Richardson, WD;Yeo, GSH;Franklin, RJM;Karadottir, RT;Rowitch, DH;Blouet, C;
PMID: 34260928 | DOI: 10.1016/j.celrep.2021.109362
The mediobasal hypothalamus (MBH; arcuate nucleus of the hypothalamus [ARH] and median eminence [ME]) is a key nutrient sensing site for the production of the complex homeostatic feedback responses required for the maintenance of energy balance. Here, we show that refeeding after an overnight fast rapidly triggers proliferation and differentiation of oligodendrocyte progenitors, leading to the production of new oligodendrocytes in the ME specifically. During this nutritional paradigm, ME perineuronal nets (PNNs), emerging regulators of ARH metabolic functions, are rapidly remodeled, and this process requires myelin regulatory factor (Myrf) in oligodendrocyte progenitors. In genetically obese ob/ob mice, nutritional regulations of ME oligodendrocyte differentiation and PNN remodeling are blunted, and enzymatic digestion of local PNN increases food intake and weight gain. We conclude that MBH PNNs are required for the maintenance of energy balance in lean mice and are remodeled in the adult ME by the nutritional control of oligodendrocyte differentiation.
Salinas CBG, Lu TT, Gabery S, Marstal K, Alanentalo T, Mercer AJ, Cornea A, Conradsen K, Hecksher-Sørensen J, Dahl AB, Knudsen LB, Secher A.
PMID: 29985439 | DOI: 10.1038/s41598-018-28496-6
Light Sheet Fluorescence Microscopy (LSFM) of whole organs, in particular the brain, offers a plethora of biological data imaged in 3D. This technique is however often hindered by cumbersome non-automated analysis methods. Here we describe an approach to fully automate the analysis by integrating with data from the Allen Institute of Brain Science (AIBS), to provide precise assessment of the distribution and action of peptide-based pharmaceuticals in the brain. To illustrate this approach, we examined the acute central nervous system effects of the glucagon-like peptide-1 (GLP-1) receptor agonist liraglutide. Peripherally administered liraglutide accessed the hypothalamus and brainstem, and led to activation in several brain regions of which most were intersected by projections from neurons in the lateral parabrachial nucleus. Collectively, we provide a rapid and unbiased analytical framework for LSFM data which enables quantification and exploration based on data from AIBS to support basic and translational discovery.