Project description:Dysfunction of motile cilia can impair mucociliary clearance in the airway and result in primary ciliary dyskinesia (PCD), a pediatric syndrome characterized by chronic respiratory infection and bronchiectasis, as well as infertility, laterality defects, and occasionally hydrocephalus due to defects in cilia in other organ systems. We have previously shown that mutations in genes encoding components of the ciliary central pair apparatus (CPA) perturb ciliary motility and result in PCD in mouse models. However, little is known about how epithelial cell types in the ciliary microenvironment of the upper airway respond to defects in ciliary motility and mucociliary clearance. In this study, we have used a single-cell RNA sequencing (scRNA-seq) approach to investigate the effects of ciliary dysfunction on the tracheal epithelial cells from mouse models with mutations in CPA genes Cfap221 (also known as Pcdp1), Cfap54, and Spef2. Expected cell types were identified in the tracheal epithelial samples, including basal cells, suprabasal cells, secretory cells, deuterosomal cells, ciliated cells, tuft cells, ionocytes, and neuroendocrine cells, as well as an unidentified cell type that does not express markers of typical airway cells. The deuterosomal cells were found to exist in two states that differ largely in expression of genes involved in differentiation into the ciliated cell type. Differentially expressed genes (DEGs) were identified for each cell type, and functional enrichment analysis revealed a variety of important cellular functions altered in mutant cells. Overlapping DEGs shed light on general cellular responses to cilia dysfunction, while unique DEGs indicate that some responses may be specific to the individual mutation and ciliary defect. These analyses uncover new information about cellular responses to mucociliary clearance defects in the airway and pathogenesis of PCD.
Project description:Current spatial transcriptomics methods identify cell types and states in a spatial context but lack morphological information. Electron microscopy, in contrast, provides structural details at nanometer resolution without decoding the diverse cellular states and identity. STEM address this limitation by correlating multiplexed error-robust FISH with electron microscopy from adjacent tissue sections. Using STEM to characterize demyelinated lesions in mice, we were able to bridge spatially resolved transcriptional data with morphological information on cell identities. This approach allowed us to link the morphology of foamy microglia and interferon-response microglia with their transcriptional signatures.
Project description:We performed whole genome gene expression profiling in bronchial biopsies from PCD patients. We used the Quality Threshold clustering algorithm to identify groups of genes that revealed highly correlated RNA expression patterns in the biopsies. The largest cluster contained 372 genes and was significantly enriched for genes related to cilia. The database and literature search showed that 16250 genes in this cluster were known cilia genes, strongly indicating that the remaining 21022 genes were likely to be new cilia genes. The tissue expression pattern of the 210 new cilia genes and the 162 known genes was consistent with the presence of motile cilia in a given tissue. Analysis of the upstream promotor sequences revealed evidence for RFX transcription factors binding site motif in both subgroups. Total RNA obtained from 6 primary ciliary dyskinesia patients and 9 control individuals
Project description:Cellular responses in the airway ciliary microenvironment from mouse models of primary ciliary dyskinesia with central pair apparatus defects
Project description:Current spatial transcriptomics methods provide molecular and spatial information but no morphological readout. Here, we present STEM - a method that correlates multiplexed error-robust FISH with electron microscopy from neighboring tissue sections of the same sample. STEM links transcriptional and spatial organization of single cells with ultrastructural morphology of the tissue in vivo. Using STEM to characterize demyelinated white-matter lesions allowed us to link morphology of myelin-laden foamy microglia to transcriptional signature. Moreover, we revealed that interferon-response microglia have unique morphology and are enriched near CD8 T-cells.
Project description:Cilia play essential roles in normal human development and health; cilia dysfunction results in diseases such as primary ciliary dyskinesia (PCD). Despite their importance, the native structure of human cilia is unknown, and structural defects in the cilia of patients are often undetectable or remain elusive because of heterogeneity. Here we develop an approach that enables visualization of human (patient) cilia at high-resolution using cryo-electron tomography of samples obtained noninvasively by nasal scrape biopsy. We present the native 3D structures of normal and PCD-causing RSPH1-mutant human respiratory cilia in unprecedented detail; this allows comparisons of cilia structure across evolutionarily distant species and reveals the previously unknown primary defect and the heterogeneous secondary defects in RSPH1-mutant cilia. Our data provide evidence for structural and functional heterogeneity in radial spokes, suggest a mechanism for the milder RSPH1 PCD phenotype and demonstrate that cryo-electron tomography can be applied to human disease by directly imaging patient samples.