Similar Datasets
Project description:In contrast to adult mammals, adult zebrafish are able to fully regenerate injured cardiac tissue, and this regeneration process requires an adequate and tightly controlled immune response. However, which immune aspects drive particular aspects of the regenerative response are unclear. Here, we report the participation and requirement of the antigen presentation-adaptive immunity axis during zebrafish cardiac regeneration. We found that, in addition to immune cells, endocardial cells start expressing antigen presentation genes following the initial innate immune response. Consistent with this finding, we observed that helper T cells, a.k.a. Cd4+ T cells, are closely associated with phosphoERK+ (pERK+) (i.e., activated) endocardial cells at these stages. We inactivated major histocompatibility complex (MHC) class II antigen presentation by generating cd74a; cd74b double mutants, which display a defective immune response. In these mutants, both Cd4+ T cells and pERK+ endocardial cells fail to efficiently infiltrate the injured tissue. Notably, this model of compromised antigen presentation exhibits additional defects in cardiac regeneration including reduced cardiomyocyte dedifferentiation and proliferation. Altogether, these findings reveal a necessary role for antigen presentation during zebrafish cardiac regeneration and point to an immune crosstalk between T cells and endocardial cells, thereby further establishing a link between the adaptive immune response and tissue regeneration.
2024-03-06 | GSE230669 | GEO
Project description:In contrast to adult mammals, adult zebrafish are able to fully regenerate injured cardiac tissue, and this regeneration process requires an adequate and tightly controlled immune response. However, which immune aspects drive particular aspects of the regenerative response are unclear. Here, we report the participation and requirement of the antigen presentation-adaptive immunity axis during zebrafish cardiac regeneration. We found that, in addition to immune cells, endocardial cells start expressing antigen presentation genes following the initial innate immune response. Consistent with this finding, we observed that helper T cells, a.k.a. Cd4+ T cells, are closely associated with phosphoERK+ (pERK+) (i.e., activated) endocardial cells at these stages. We inactivated major histocompatibility complex (MHC) class II antigen presentation by generating cd74a; cd74b double mutants, which display a defective immune response. In these mutants, both Cd4+ T cells and pERK+ endocardial cells fail to efficiently infiltrate the injured tissue. Notably, this model of compromised antigen presentation exhibits additional defects in cardiac regeneration including reduced cardiomyocyte dedifferentiation and proliferation. Altogether, these findings reveal a necessary role for antigen presentation during zebrafish cardiac regeneration and point to an immune crosstalk between T cells and endocardial cells, thereby further establishing a link between the adaptive immune response and tissue regeneration.
2024-03-06 | GSE232060 | GEO
Project description:In contrast to adult mammals, adult zebrafish are able to fully regenerate injured cardiac tissue, and this regeneration process requires an adequate and tightly controlled immune response. However, which immune aspects drive particular aspects of the regenerative response are unclear. Here, we report the participation and requirement of the antigen presentation-adaptive immunity axis during zebrafish cardiac regeneration. We found that, in addition to immune cells, endocardial cells start expressing antigen presentation genes following the initial innate immune response. Consistent with this finding, we observed that helper T cells, a.k.a. Cd4+ T cells, are closely associated with phosphoERK+ (pERK+) (i.e., activated) endocardial cells at these stages. We inactivated major histocompatibility complex (MHC) class II antigen presentation by generating cd74a; cd74b double mutants, which display a defective immune response. In these mutants, both Cd4+ T cells and pERK+ endocardial cells fail to efficiently infiltrate the injured tissue. Notably, this model of compromised antigen presentation exhibits additional defects in cardiac regeneration including reduced cardiomyocyte dedifferentiation and proliferation. Altogether, these findings reveal a necessary role for antigen presentation during zebrafish cardiac regeneration and point to an immune crosstalk between T cells and endocardial cells, thereby further establishing a link between the adaptive immune response and tissue regeneration.
2024-03-06 | GSE232059 | GEO
Project description:Heart regeneration requires replenishment of lost cardiomyocytes (CMs) and cells of the endocardial lining. However, the signaling regulation and transcriptional control of myocardial dedifferentiation and endocardial activation are incompletely understood during cardiac regeneration. Here, we report that T-Box Transcription Factor 20 (Tbx20) is induced rapidly in the myocardial wound edge in response to various sources of cardiac damages in zebrafish. Inducing Tbx20 specifically in the adult myocardium promotes injury-induced CM proliferation through CM dedifferentiation, leading to loss of CM cellular contacts and re-expression of cardiac embryonic or fetal gene programs. Unexpectedly, we identify that myocardial Tbx20 induction activates the endocardium at the injury site with enhanced endocardial cell extension and proliferation, where it induces the endocardial Bone morphogenetic protein 6 (Bmp6) signaling. Pharmacologically inactivating endocardial Bmp6 signaling reduces expression of its targets, Id1 and Id2b, attenuating the increased endocardial regeneration in tbx20-overexpressing hearts. Altogether, our study demonstrates that Tbx20 induction promotes adult heart regeneration by inducing cardiomyocyte dedifferentiation as well as non-cell-autonomously enhancing endocardial cell regeneration.
| S-EPMC7417483 | biostudies-literature
Project description:In mammals, dendritic cells (DCs) form the key link between the innate and adaptive immune systems. DCs act as immune sentries in various tissues and, upon encountering pathogen, engulf and traffic foreign antigen to secondary lymphoid tissues, stimulating antigen-specific T lymphocytes. Although DCs are of fundamental importance in orchestrating the mammalian immune response, their presence and function in nonmammalian vertebrates is largely unknown. Because teleosts possess one of the earliest recognizable adaptive immune systems, we sought to identify antigen-presenting cells (APCs) in the zebrafish to better understand the potential origins of DCs and their evolutionary relationship to lymphocytes. Here we present the identification and characterization of a zebrafish APC subset strongly resembling mammalian DCs. Rare DCs are present in various adult tissues, and can be enriched by their affinity for the lectin peanut agglutinin (PNA). We show that PNA(hi) myeloid cells possess the classical morphological features of mammalian DCs as revealed by histochemical and ultrastructural analyses, phagocytose-labeled bacterial preparations in vivo, and exhibit expression of genes associated with DC function and antigen presentation, including il12, MHC class II invariant chain iclp1, and csf1r. Importantly, we show that PNA(hi) cells can activate T lymphocytes in an antigen-dependent manner. Together, these studies suggest that the cellular constituents responsible for antigen presentation are remarkably conserved from teleosts to mammals, and indicate that the zebrafish may serve as a unique model to study the origin of APC subsets and their evolutionary role as the link between the innate and adaptive immune systems.
| S-EPMC2936643 | biostudies-other
Project description:NKT cells have been shown to promote peripheral tolerance in a number of model systems, yet the processes by which they exert their regulatory effects remain poorly understood. Here, we show that soluble factors secreted by human NKT cells instruct human peripheral blood monocytes to differentiate into myeloid APCs that have suppressive properties. NKT instructed monocytes acquired a cell surface phenotype resembling myeloid DCs. However, whereas control DCs that were generated by culturing monocytes with recombinant GM-CSF and IL-4 had a proinflammatory phenotype characterized by the production of IL-12 with little IL-10, NKT-instructed APCs showed the opposite cytokine production profile of high IL-10 with little or no IL-12. The control DCs efficiently stimulated peripheral blood T cell IFN-gamma secretion and proliferation, whereas NKT-instructed APCs silenced these T cell responses. Exposure to NKT cell factors had a dominant effect on the functional properties of the DCs, since DCs differentiated by recombinant GM-CSF and IL-4 in the presence of NKT cell factors inhibited T cell responses. To confirm their noninflammatory effects, NKT-instructed APCs were tested in an in vivo assay that depends on the activation of antigen-specific human T cells. Control DCs promoted substantial tissue inflammation; however, despite a marked neutrophilic infiltrate, there was little edema in the presence of NKT-instructed APCs, suggesting the inflammatory cascade was held in check. These results point to a novel pathway initiated by NKT cells that can contribute to the regulation of human antigen-specific Th1 responses.
| S-EPMC2752012 | biostudies-literature
Project description:Function of the heart begins long before its formation is complete. Analyses in mouse and zebrafish have shown that myocardial function is not required for early steps of organogenesis, such as formation of the heart tube or chamber specification. However, whether myocardial function is required for later steps of cardiac development, such as endocardial cushion (EC) formation, has not been established. Recent technical advances and approaches have provided novel inroads toward the study of organogenesis, allowing us to examine the effects of both genetic and pharmacological perturbations of myocardial function on EC formation in zebrafish. To address whether myocardial function is required for EC formation, we examined silent heart (sih(-/-)) embryos, which lack a heartbeat due to mutation of cardiac troponin T (tnnt2), and observed that atrioventricular (AV) ECs do not form. Likewise, we determined that cushion formation is blocked in cardiofunk (cfk(-/-)) embryos, which exhibit cardiac dilation and no early blood flow. In order to further analyze the heart defects in cfk(-/-) embryos, we positionally cloned cfk and show that it encodes a novel sarcomeric actin expressed in the embryonic myocardium. The Cfk(s11) variant exhibits a change in a universally conserved residue (R177H). We show that in yeast this mutation negatively affects actin polymerization. Because the lack of cushion formation in sih- and cfk-mutant embryos could be due to reduced myocardial function and/or lack of blood flow, we approached this question pharmacologically and provide evidence that reduction in myocardial function is primarily responsible for the defect in cushion development. Our data demonstrate that early myocardial function is required for later steps of organogenesis and suggest that myocardial function, not endothelial shear stress, is the major epigenetic factor controlling late heart development. Based on these observations, we postulate that defects in cardiac morphogenesis may be secondary to mutations affecting early myocardial function, and that, in humans, mutations affecting embryonic myocardial function may be responsible for structural congenital heart disease.
| S-EPMC406391 | biostudies-literature
Project description:The cardiac lymphatic vascular system and its potentially critical functions in heart patients have been largely underappreciated, in part due to a lack of experimentally accessible systems. We here demonstrate that cardiac lymphatic vessels develop in young adult zebrafish, using coronary arteries to guide their expansion down the ventricle. Mechanistically, we show that in cxcr4a mutants with defective coronary artery development, cardiac lymphatic vessels fail to expand onto the ventricle. In regenerating adult zebrafish hearts the lymphatic vasculature undergoes extensive lymphangiogenesis in response to a cryoinjury. A significant defect in reducing the scar size after cryoinjury is observed in zebrafish with impaired Vegfc/Vegfr3 signaling that fail to develop intact cardiac lymphatic vessels. These results suggest that the cardiac lymphatic system can influence the regenerative potential of the myocardium.
| S-EPMC6881116 | biostudies-literature
Project description:Mutations in cardiac actin (ACTC) have been associated with different cardiac abnormalities in humans, including dilated cardiomyopathy and septal defects. However, it is still poorly understood how altered ACTC structure affects cardiovascular physiology and results in the development of distinct congenital disorders. A zebrafish mutant (s434 mutation) was identified that displays blood regurgitation in a dilated heart and lacks endocardial cushion (EC) formation. We identified the mutation as a single nucleotide change in the alpha-cardiac actin 1a gene (actc1a), resulting in a Y169S amino acid substitution. This mutation is located at the W-loop of actin, which has been implicated in nucleotide sensing. Consequently, s434 mutants show loss of polymerized cardiac actin. An analogous mutation in yeast actin results in rapid depolymerization of F-actin into fragments that cannot reanneal. This polymerization defect can be partially rescued by phalloidin treatment, which stabilizes F-actin. In addition, actc1a mutants show defects in cardiac contractility and altered blood flow within the heart tube. This leads to downregulation or mislocalization of EC-specific gene expression and results in the absence of EC development. Our study underscores the importance of the W-loop for actin functionality and will help us to understand the structural and physiological consequences of ACTC mutations in human congenital disorders.
| S-EPMC3422001 | biostudies-literature
Project description:Ischemic cardiopathy is the leading cause of death in the world, for which efficient regenerative therapy is not currently available. In mammals, after a myocardial infarction episode, the damaged myocardium is replaced by scar tissue featuring collagen deposition and tissue remodelling with negligible cardiomyocyte proliferation. Zebrafish, in contrast, display an extensive regenerative capacity as they are able to restore completely lost cardiac tissue after partial ventricular amputation. Due to the lack of genetic lineage tracing evidence, it is not yet clear if new cardiomyocytes arise from existing contractile cells or from an uncharacterised set of progenitors cells. Nonetheless, several genes and molecules have been shown to participate in this process, some of them being cardiomyocyte mitogens in vitro. Though questions as what are the early signals that drive the regenerative response and what is the relative role of each cardiac cell in this process still need to be answered, the zebrafish is emerging as a very valuable tool to understand heart regeneration and devise strategies that may be of potential value to treat human cardiac disease. Here, we performed a genome-wide transcriptome profile analysis focusing on the early time points of zebrafish heart regeneration and compared our results with those of previously published data. Our analyses confirmed the differential expression of several transcripts, and identified additional genes the expression of which is differentially regulated during zebrafish heart regeneration. We validated the microarray data by conventional and/or quantitative RT-PCR. For a subset of these genes, their expression pattern was analyzed by in situ hybridization and shown to be upregulated in the regenerating area of the heart. The specific role of these new transcripts during zebrafish heart regeneration was further investigated ex vivo using primary cultures of zebrafish cardiomyocytes and/or epicardial cells. Our results offer new insights into the biology of heart regeneration in the zebrafish and, together with future experiments in mammals, may be of potential interest for clinical applications. In order to study zebrafish heart regeneration, a time course experiment was realized where amputated heart regenerating were compared to control heart. Samples in triplicate were extracted at 1, 3, 5 and 7 days post-amputation.
2010-03-09 | E-GEOD-17993 | biostudies-arrayexpress