Hauling, T. | Search bioRxiv

bioRxiv2019

Spatial and temporal localization of immune transcripts defines hallmarks and diversity in the tuberculosis granuloma

Granulomas are the pathological hallmark of Tuberculosis (TB), and the niche in which bacilli can either grow and disseminate or the immunological microenvironment in which host cells interact to prevent bacterial dissemination. Here, after in situ sequencing, thirty-four immune transcripts in lung sections from Mycobacterium tuberculosis-infected mice were aligned to the tissue morphology at cellular resolution, allowing the analysis of local immune interactions in the granuloma.\n\nCo-localizing transcript networks at <10 m in C57BL/6 mouse granulomas increased in complexity with time after infection. B-cell clusters developed late after infection. Transcripts from activated macrophages were enriched at subcellular distances from M. tuberculosis. Encapsulated C3HeB/FeJ granulomas showed necrotic centers with transcripts associated with immunosuppression (foxp3, il10), while those in the granuloma rims associated with activated T cells and macrophages. Highly diverse networks with common interactors were observed in similar lesions.\n\nThus, different immune landscapes of M. tuberculosis granulomas depending on the time after infection, the histopathological features of the lesion and the proximity to bacteria were here defined.

immunology↗

bioRxiv2018

A spatial atlas of inhibitory cell types in mouse hippocampus

Understanding the function of a tissue requires knowing the spatial organization of its constituent cell types. In the cerebral cortex, single-cell RNA sequencing (scRNA-seq) has revealed the genome-wide expression patterns that define its many, closely related cell types, but cannot reveal their spatial arrangement. Here we introduce probabilistic cell typing by in situ sequencing (pciSeq), an approach that leverages prior scRNA-seq classification to identify cell types using multiplexed in situ RNA detection. We applied this method to map the inhibitory neurons of hippocampal area CA1, a cell system critical for memory function, for which ground truth is available from extensive prior work identifying the laminar organization of subtly differing cell types. Our method confidently identified 16 interneuron classes, in a spatial arrangement closely matching ground truth. This method will allow identifying the spatial organization of fine cell types across the brain and other tissues.

neuroscience↗