Analysis of target mRNAs in the fixed-frozen human brain using a modified BaseScope-ISH Assay protocol

STAR Protocols

2022 Dec 01

Carisì, M;Howell, O;Morgan, A;Davies, J;
| DOI: 10.1016/j.xpro.2022.101896

We describe a modified BaseScope Assay protocol (ACDBio) for RNA in situ hybridization on fixed-frozen human brain tissue. The original protocol caused tissue detachment due to harsh tissue pre-treatment. We therefore optimized it to improve tissue stability while providing high stain quality in fragile post-mortem tissue from aged donors with advanced neurodegeneration. The main changes include two additional fixation steps and modifications to the pre-treatment protocol. We also describe tissue imaging and stain quantification using the open-source QuPath software. For complete details on the use and execution of this protocol, please refer to Hornsby et al. (2020).

The Role of Inflammatory Cells in Tumor Angiogenesis

The Extracellular Matrix and the Tumor Microenvironment

2022 Jul 07

Tamma, R;Annese, T;Ribatti, D;
| DOI: 10.1007/978-3-030-99708-3_14

Tumor growth depends on angiogenesis. The complex tissue environment surrounding tumor cells, which is composed of a variety of resident and infiltrating host cells, secreted factors and extracellular matrix proteins, influences tumor angiogenesis and progression. Moreover, the tumor microenvironment contributes to determining therapeutic responses and resistance to therapy. The ability to block tumor resistance is related to the understanding of the cellular and molecular pathways activated in the tumor microenvironment. Novel emerging targeted therapeutic strategies are based on the combination of different antitumor approaches with the aim of resolving refractory tumors and improving cancer treatment efficiency.

Fast deep neural correspondence for tracking and identifying neurons in C. elegans using semi-synthetic training

eLife

2021 Jul 14

Yu, X;Creamer, MS;Randi, F;Sharma, AK;Linderman, SW;Leifer, AM;
PMID: 34259623 | DOI: 10.7554/eLife.66410

We present an automated method to track and identify neurons in C. elegans, called 'fast Deep Neural Correspondence' or fDNC, based on the transformer network architecture. The model is trained once on empirically derived semi-synthetic data and then predicts neural correspondence across held-out real animals. The same pre-trained model both tracks neurons across time and identifies corresponding neurons across individuals. Performance is evaluated against hand-annotated datasets, including NeuroPAL [1]. Using only position information, the method achieves 79.1% accuracy at tracking neurons within an individual and 64.1% accuracy at identifying neurons across individuals. Accuracy at identifying neurons across individuals is even higher (78.2%) when the model is applied to a dataset

Female-specific synaptic dysfunction and cognitive impairment in a mouse model of PCDH19 disorder

Science (New York, N.Y.)

2021 Apr 16

Hoshina, N;Johnson-Venkatesh, EM;Hoshina, M;Umemori, H;
PMID: 33859005 | DOI: 10.1126/science.aaz3893

Protocadherin-19 (PCDH19) mutations cause early-onset seizures and cognitive impairment. The PCDH19 gene is on the X-chromosome. Unlike most X-linked disorders, PCDH19 mutations affect heterozygous females (PCDH19HET♀ ) but not hemizygous males (PCDH19HEMI♂ ); however, the reason why remains to be elucidated. We demonstrate that PCDH19, a cell-adhesion molecule, is enriched at hippocampal mossy fiber synapses. Pcdh19HET♀ but not Pcdh19HEMI♂ mice show impaired mossy fiber synaptic structure and physiology. Consistently, Pcdh19HET♀ but not Pcdh19HEMI♂ mice exhibit reduced pattern completion and separation abilities, which require mossy fiber synaptic function. Furthermore, PCDH19 appears to interact with N-cadherin at mossy fiber synapses. In Pcdh19HET♀ conditions, mismatch between PCDH19 and N-cadherin diminishes N-cadherin-dependent signaling and impairs mossy fiber synapse development; N-cadherin overexpression rescues Pcdh19HET♀ phenotypes. These results reveal previously unknown molecular and cellular mechanisms underlying the female-specific PCDH19 disorder phenotype.

Reporter Selection and Postmortem Methods to Verify Transgene Expression

Vectorology for Optogenetics and Chemogenetics

2023 Feb 07

Heffernan, K;Smith, Y;Galvan, A;
| DOI: 10.1007/978-1-0716-2918-5_15

The accurate localization of transgene expression after viral vector delivery is essential to the interpretation of experiments based on genetic-based approaches, such as chemo- or optogenetics. Postmortem histological analysis can be used to examine the injection target, the extent of the virus transduction, the types of cells expressing the transgene, and the subcellular localization of the protein. In this chapter, we will provide a general description of methods to identify transgene expression, immunocytochemistry protocols, and examples of specific protocols. We close the chapter with an example of an application of electron microscopy to identify the localization of transgene expression.

Dual-specificity RNA aptamers enable manipulation of target-specific O-GlcNAcylation and unveil functions of O-GlcNAc on β-catenin

Cell

2023 Jan 19

Zhu, Y;Hart, GW;
PMID: 36626902 | DOI: 10.1016/j.cell.2022.12.016

O-GlcNAc is a dynamic post-translational modification (PTM) that regulates protein functions. In studying the regulatory roles of O-GlcNAc, a major roadblock is the inability to change O-GlcNAcylation on a single protein at a time. Herein, we developed a dual RNA-aptamer-based approach that simultaneously targeted O-GlcNAc transferase (OGT) and β-catenin, the key transcription factor of the Wnt signaling pathway, to selectively increase O-GlcNAcylation of the latter without affecting other OGT substrates. Using the OGT/β-catenin dual-specificity aptamers, we found that O-GlcNAcylation of β-catenin stabilizes the protein by inhibiting its interaction with β-TrCP. O-GlcNAc also increases β-catenin's interaction with EZH2, recruits EZH2 to promoters, and dramatically alters the transcriptome. Further, by coupling riboswitches or an inducible expression system to aptamers, we enabled inducible regulation of protein-specific O-GlcNAcylation. Together, our findings demonstrate the efficacy and versatility of dual-specificity aptamers for regulating O-GlcNAcylation on individual proteins.

Towards a definition of microglia heterogeneity

Communications biology

2022 Oct 20

Healy, LM;Zia, S;Plemel, JR;
PMID: 36266565 | DOI: 10.1038/s42003-022-04081-6

High dimensional single-cell analysis such as single cell and single nucleus RNA sequencing (sc/snRNAseq) are currently being widely applied to explore microglia diversity. The use of sc/snRNAseq provides a powerful and unbiased approach to deconvolve heterogeneous cellular populations. However, sc/snRNAseq and analyses pipelines are designed to find heterogeneity. Indeed, cellular heterogeneity is often the most frequently reported finding. In this Perspective, we consider the ubiquitous concept of heterogeneity focusing on its application to microglia research and its influence on the field of neuroimmunology. We suggest that a clear understanding of the semantic and biological implications of microglia heterogeneity is essential for mitigating confusion among researchers.

Cell-specific RNA purification to study translatomes of mouse central nervous system

STAR protocols

2022 Jun 17

Bravo-Ferrer, I;Khakh, BS;Díaz-Castro, B;
PMID: 35620074 | DOI: 10.1016/j.xpro.2022.101397

Cell-specific RNA sequencing has revolutionized the study of cell biology. Here, we present a protocol to assess cell-specific translatomes of genetically targeted cell types. We focus on astrocytes and describe RNA purification using RiboTag tools. Unlike single-cell RNA sequencing, this approach allows high sequencing depth to detect low expression genes, and the exploration of RNAs translated in subcellular compartments. Furthermore, it avoids underestimation of transcripts from cells susceptible to cell isolation procedures. The protocol can be applied to a variety of cell types. For complete details on the use and execution of this protocol, please refer to Chai et al. (2017), Díaz-Castro et al. (2021), Díaz-Castro et al. (2019), Srinivasan et al. (2016), and Yu et al. (2018).

Studying of Molecular Regulation of Developmental Processes of Lower Metazoans Exemplified by Cnidaria Using High-Throughput Sequencing

Biochemistry (Moscow)

2022 Mar 01

Erofeeva, T;Grigorenko, A;Gusev, F;Kosevich, I;Rogaev, E;
| DOI: 10.1134/S0006297922030075

A unique set of features and characteristics of species of the Cnidaria phylum is the one reason that makes them a model for a various studies. The plasticity of a life cycle and the processes of cell differentiation and development of an integral multicellular organism associated with it are of a specific scientific interest. A new stage of development of molecular genetic methods, including methods for high-throughput genome, transcriptome, and epigenome sequencing, both at the level of the whole organism and at the level of individual cells, makes it possible to obtain a detailed picture of the development of these animals. This review examines some modern approaches and advances in the reconstruction of the processes of ontogenesis of cnidarians by studying the regulatory signal transduction pathways and their interactions.

GABA-receptive microglia selectively sculpt developing inhibitory circuits

Cell

2021 Jul 22

Favuzzi, E;Huang, S;Saldi, GA;Binan, L;Ibrahim, LA;Fernández-Otero, M;Cao, Y;Zeine, A;Sefah, A;Zheng, K;Xu, Q;Khlestova, E;Farhi, SL;Bonneau, R;Datta, SR;Stevens, B;Fishell, G;
PMID: 34233165 | DOI: 10.1016/j.cell.2021.06.018

Microglia, the resident immune cells of the brain, have emerged as crucial regulators of synaptic refinement and brain wiring. However, whether the remodeling of distinct synapse types during development is mediated by specialized microglia is unknown. Here, we show that GABA-receptive microglia selectively interact with inhibitory cortical synapses during a critical window of mouse postnatal development. GABA initiates a transcriptional synapse remodeling program within these specialized microglia, which in turn sculpt inhibitory connectivity without impacting excitatory synapses. Ablation of GABAB receptors within microglia impairs this process and leads to behavioral abnormalities. These findings demonstrate that brain wiring relies on the selective communication between matched neuronal and glial cell types.

Embryo-scale, single-cell spatial transcriptomics

Science (New York, N.Y.)

2021 Jul 02

Srivatsan, SR;Regier, MC;Barkan, E;Franks, JM;Packer, JS;Grosjean, P;Duran, M;Saxton, S;Ladd, JJ;Spielmann, M;Lois, C;Lampe, PD;Shendure, J;Stevens, KR;Trapnell, C;
PMID: 34210887 | DOI: 10.1126/science.abb9536

Spatial patterns of gene expression manifest at scales ranging from local (e.g., cell-cell interactions) to global (e.g., body axis patterning). However, current spatial transcriptomics methods either average local contexts or are restricted to limited fields of view. Here, we introduce sci-Space, which retains single-cell resolution while resolving spatial heterogeneity at larger scales. Applying sci-Space to developing mouse embryos, we captured approximate spatial coordinates and whole transcriptomes of about 120,000 nuclei. We identify thousands of genes exhibiting anatomically patterned expression, leverage spatial information to annotate cellular subtypes, show that cell types vary substantially in their extent of spatial patterning, and reveal correlations between pseudotime and the migratory patterns of differentiating neurons. Looking forward, we anticipate that sci-Space will facilitate the construction of spatially resolved single-cell atlases of mammalian development.

A constant pool of Lgr5+ intestinal stem cells is required for intestinal homeostasis

Cell reports

2021 Jan 26

Tan, SH;Phuah, P;Tan, LT;Yada, S;Goh, J;Tomaz, LB;Chua, M;Wong, E;Lee, B;Barker, N;
PMID: 33503423 | DOI: 10.1016/j.celrep.2020.108633

Lgr5+ crypt base columnar cells, the operational intestinal stem cells (ISCs), are thought to be dispensable for small intestinal (SI) homeostasis. Using a Lgr5-2A-DTR (diphtheria toxin receptor) model, which ablates Lgr5+ cells with near-complete efficiency and retains endogenous levels of Lgr5 expression, we show that persistent depletion of Lgr5+ ISCs in fact compromises SI epithelial integrity and reduces epithelial turnover in vivo. In vitro, Lgr5-2A-DTR SI organoids are unable to establish or survive when Lgr5+ ISCs are continuously eliminated by adding DT to the media. However, transient exposure to DT at the start of culture allows organoids to form, and the rate of outgrowth reduces with the increasing length of DT presence. Our results indicate that intestinal homeostasis requires a constant pool of Lgr5+ ISCs, which is supplied by rapidly reprogrammed non-Lgr5+ crypt populations when preexisting Lgr5+ ISCs are ablated.

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	Description
sense Example: Hs-LAG3-sense	Standard probes for RNA detection are in antisense. Sense probe is reverse complent to the corresponding antisense probe.
Intron# Example: Mm-Htt-intron2	Probe targets the indicated intron in the target gene, commonly used for pre-mRNA detection
Pool/Pan Example: Hs-CD3-pool (Hs-CD3D, Hs-CD3E, Hs-CD3G)	A mixture of multiple probe sets targeting multiple genes or transcripts
No-XSp Example: Hs-PDGFB-No-XMm	Does not cross detect with the species (Sp)
XSp Example: Rn-Pde9a-XMm	designed to cross detect with the species (Sp)
O# Example: Mm-Islr-O1	Alternative design targeting different regions of the same transcript or isoforms
CDS Example: Hs-SLC31A-CDS	Probe targets the protein-coding sequence only
EnEm	Probe targets exons n and m
En-Em	Probe targets region from exon n to exon m
Retired Nomenclature
tvn Example: Hs-LEPR-tv1	Designed to target transcript variant n
ORF Example: Hs-ACVRL1-ORF	Probe targets open reading frame
UTR Example: Hs-HTT-UTR-C3	Probe targets the untranslated region (non-protein-coding region) only
5UTR Example: Hs-GNRHR-5UTR	Probe targets the 5' untranslated region only
3UTR Example: Rn-Npy1r-3UTR	Probe targets the 3' untranslated region only
Pan Example: Pool	A mixture of multiple probe sets targeting multiple genes or transcripts

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