Project description:To profile the diversity of cell types present in adult zebrafish synovial joints, we performed single-cell RNA sequencing of the uninjured adult jaw joint and identified multiple skeletal, connective tissue, and fibroblast subtypes, including a joint-specific periosteal population.
Project description:The specification and maintenance of distinct zones of chondrocytes within growth plates and joints ensures proper skeletal development through adulthood. Rare mutations in the transcription factor NKX3.2 underlie Spondylo-megaepiphyseal-metaphyseal dysplasia (SMMD), which is characterized by skeletal defects including scoliosis, large epiphyses, wide growth plates, and supernumerary joints in the distal limbs. Embryonic knockdown of nkx3.2 function in zebrafish had revealed a requirement in jaw joint specification, yet embryonic lethality of nkx3.2 knockdown zebrafish and mouse Nkx3.2 mutants had precluded an analysis of post-embryonic functions. Here we report adult viable nkx3.2 zebrafish mutants that display ectopic cartilage overgrowth in place of a missing jaw joint, as well as severe dysmorphologies of the facial skeleton, skullcap, and spine. We also isolate rare viable nkx3.2 knockdown animals that lack the jaw joint but fail to display ectopic cartilage growth and scoliosis, indicating post-embryonic roles for Nkx3.2 beyond jaw joint specification. Consistently, we observe nkx3.2 expression in the subarticular zone of the adult jaw joint and in pre-hypertrophic growth plate chondrocytes. Single-cell RNA sequencing reveals an upregulation of stress-induced pathways in mutants, including the prostaglandin D2 synthase ptgdsb.1 and the mTOR regulator sestrin1, which we confirm by in situ RNA analysis of the defective jaw joint region. Our data reveal a zebrafish model for the joint and spine defects of SMMD and point to post-embryonic roles for Nkx3.2 in buffering the stress response and dampening proliferation in joint-adjacent chondrocytes.
Project description:The functional jaw is composed of multiple connective tissues including skeletal components (bone, cartilage, and teeth), tendon, ligament, and musculature. Cranial neural crest-derived mesenchyme of the mandibular arch give rise to diverse tissue types within the lower jaw. To understand how the specification of diverse cell types with spatial and temporal precision is achieved, we profile multi-omic chromatin accessibility (snATACseq) and transcriptome (snRNAseq) of jaw mesenchyme at single-cell resolution from the developing zebrafish jaw.
Project description:Acute exposure to acrylamide (ACR), a type-2 alkene, may lead to a ataxia, skeletal muscles weakness and numbness of the extremities in exposed human and laboratory animals. Recently, a zebrafish model for ACR neurotoxicity mimicking most of the pathophysiological processes described in mammalian models, was generated in 8 days post-fertilization larvae. In order to better understand the predictive value of the zebrafish larvae model of acute ACR neurotoxicity, in the present manuscript the ACR acute neurotoxicity has been characterized in the brain of adult zebrafish, and the results compared with those obtained with the whole-larvae. Although qualitative and quantitative analysis of the data shows important differences in the ACR effects between the adult brain and the whole-larvae, the overall effects of ACR in adult zebrafish, including a significant decrease in locomotor activity, altered expression of transcriptional markers of proteins involved in synaptic vesicle cycle, presence of ACR-adducts on cysteine residues of some synaptic proteins, and changes in the profile of some neurotransmitter systems, are similar to those described in the larvae. Thus, these results support the suitability of the zebrafish ACR acute neurotoxicity recently developed in larvae for screening of molecules with therapeutic value to treat this toxic neuropathy.
Project description:Liver fibrosis is the excessive accumulation of extracellular matrix that can progress to cirrhosis and failure if untreated. The mechanisms of fibrogenesis are multi-faceted and remain elusive with no approved antifibrotic treatments available. Here we use single-cell RNA sequencing (scRNA-seq) of the adult zebrafish liver to study the molecular and cellular dynamics of the liver at a single-cell level and demonstrate the value of the adult zebrafish as a model for studying liver fibrosis. scRNA-seq reveals transcriptionally unique populations of hepatic cell types that comprise the zebrafish liver. Joint clustering with human liver scRNA-seq data demonstrates high conservation of transcriptional profiles and human marker genes in zebrafish cell types. Human and zebrafish hepatic stellate cells (HSCs), the driver cell in liver fibrosis, specifically show conservation of transcriptional profiles and we uncover Colec11 as a novel, conserved marker for zebrafish HSCs. To demonstrate the power of scRNA-seq to study liver fibrosis, we performed scRNA-seq on our zebrafish model of a pediatric liver disease with characteristic early, progressive liver fibrosis caused by mutation in mannose phosphate isomerase (MPI). Comparison of differentially expressed genes from human and zebrafish MPI mutant HSC datasets demonstrated similar activation of fibrosis signaling pathways and upstream regulators. CellPhoneDB analysis revealed important receptor-ligand interactions within normal and fibrotic states. This study establishes the first scRNA-seq atlas of the adult zebrafish liver, highlights the high degree of similarity to the human liver, and strengthens its value as a model to study liver fibrosis.
Project description:In this study, we have pooled 3 adult wild-type Zebrafish retinas and performed Single-Cell RNA Sequencing. We would like to see the transcriptomic signatures of each cell type in the retina. The data provided here will provide a foundation for other studies to further investigate the transcriptomic retinal enviromnent and compare how their models differ from WT.
Project description:Vertebrate vision is mediated by two kinds of photoreceptors, rods and cones, responsible for dim- and bright-light vision, respectively. Gene expression differences among cone subtypes remain poorly understood compared with rods. We generated single-cell transcriptome data using a droplet-based approach to reveal the extent of gene expression diversity among adult zebrafish photoreceptor subtypes. Populations of photoreceptor cells were enriched by using the transgenic zebrafish lines, Tg(rho:EGFP)ja2Tg and Tg(gnat2:EGFP)ja23Tg, which express GFP in rods and all cone subtypes, respectively. By analyzing the single-cell transcriptomes, we found that in addition to the four canonical zebrafish cone types (ultraviolet, blue, green and red), there exist subpopulations of green and red cones in the ventral retina that express red-shifted opsin paralogs (opn1mw4 and opn1lw1). This work lays a foundation for future studies aimed at understanding how molecular differences among cone subtypes affect photoreceptor function.
Project description:Transcriptome data from individual lck:GFP expressing cells isolated from spleens of two adult Zebrafish. LCK is a marker of lymphocytes and here we identified two major subpopulations corresponding to T-cells and NK-like and a minor one of myeloid-like cells. Single cell transcriptomes are matched with FACS index sorting data (GFP, forward and side light scatter and dead cell staining)