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Cell Jun 2021Organoids capable of forming tissue-like structures have transformed our ability to model human development and disease. With the notable exception of the human heart,...
Organoids capable of forming tissue-like structures have transformed our ability to model human development and disease. With the notable exception of the human heart, lineage-specific self-organizing organoids have been reported for all major organs. Here, we established self-organizing cardioids from human pluripotent stem cells that intrinsically specify, pattern, and morph into chamber-like structures containing a cavity. Cardioid complexity can be controlled by signaling that instructs the separation of cardiomyocyte and endothelial layers and by directing epicardial spreading, inward migration, and differentiation. We find that cavity morphogenesis is governed by a mesodermal WNT-BMP signaling axis and requires its target HAND1, a transcription factor linked to developmental heart chamber defects. Upon cryoinjury, cardioids initiated a cell-type-dependent accumulation of extracellular matrix, an early hallmark of both regeneration and heart disease. Thus, human cardioids represent a powerful platform to mechanistically dissect self-organization, congenital heart defects and serve as a foundation for future translational research.
Topics: Activins; Animals; Basic Helix-Loop-Helix Transcription Factors; Bone Morphogenetic Proteins; Calcium; Cell Line; Cell Lineage; Chickens; Endothelial Cells; Extracellular Matrix Proteins; Female; Fibroblasts; Heart; Homeobox Protein Nkx-2.5; Humans; Male; Mesoderm; Models, Biological; Myocardium; Organogenesis; Organoids; Pluripotent Stem Cells; Vascular Endothelial Growth Factor A; Wnt Proteins
PubMed: 34019794
DOI: 10.1016/j.cell.2021.04.034 -
The European Respiratory Journal Aug 2019A comprehensive understanding of the changes in gene expression in cell types involved in idiopathic pulmonary fibrosis (IPF) will shed light on the mechanisms...
A comprehensive understanding of the changes in gene expression in cell types involved in idiopathic pulmonary fibrosis (IPF) will shed light on the mechanisms underlying the loss of alveolar epithelial cells and development of honeycomb cysts and fibroblastic foci. We sought to understand changes in IPF lung cell transcriptomes and gain insight into innate immune aspects of pathogenesis.We investigated IPF pathogenesis using single-cell RNA-sequencing of fresh lung explants, comparing human IPF fibrotic lower lobes reflecting late disease, upper lobes reflecting early disease and normal lungs.IPF lower lobes showed increased fibroblasts, and basal, ciliated, goblet and club cells, but decreased alveolar epithelial cells, and marked alterations in inflammatory cells. We found three discrete macrophage subpopulations in normal and fibrotic lungs, one expressing monocyte markers, one highly expressing and (FABP4), and one highly expressing and (SPP1). SPP1 macrophages in fibrotic lower lobes showed highly upregulated and expression. Low-level local proliferation of SPP1 macrophages in normal lungs was strikingly increased in IPF lungs.Co-localisation and causal modelling supported the role for these highly proliferative SPP1 macrophages in activation of IPF myofibroblasts in lung fibrosis. These data suggest that SPP1 macrophages contribute importantly to lung fibrosis in IPF, and that therapeutic strategies targeting MERTK and macrophage proliferation may show promise for treatment of this disease.
Topics: Cell Proliferation; Epithelial Cells; Fatty Acid-Binding Proteins; Fibroblasts; Humans; Idiopathic Pulmonary Fibrosis; Immune System; Immunity, Innate; Inhibin-beta Subunits; Lung; Macrophages; Myofibroblasts; Osteopontin; Sequence Analysis, RNA; Single-Cell Analysis; Stochastic Processes; c-Mer Tyrosine Kinase
PubMed: 31221805
DOI: 10.1183/13993003.02441-2018 -
Science Translational Medicine May 2020Human genetics, biomarker, and animal studies implicate loss of function in bone morphogenetic protein (BMP) signaling and maladaptive transforming growth factor-β...
Human genetics, biomarker, and animal studies implicate loss of function in bone morphogenetic protein (BMP) signaling and maladaptive transforming growth factor-β (TGFβ) signaling as drivers of pulmonary arterial hypertension (PAH). Although sharing common receptors and effectors with BMP/TGFβ, the function of activin and growth and differentiation factor (GDF) ligands in PAH are less well defined. Increased expression of GDF8, GDF11, and activin A was detected in lung lesions from humans with PAH and experimental rodent models of pulmonary hypertension (PH). ACTRIIA-Fc, a potent GDF8/11 and activin ligand trap, was used to test the roles of these ligands in animal and cellular models of PH. By blocking GDF8/11- and activin-mediated SMAD2/3 activation in vascular cells, ACTRIIA-Fc attenuated proliferation of pulmonary arterial smooth muscle cells and pulmonary microvascular endothelial cells. In several experimental models of PH, prophylactic administration of ACTRIIA-Fc markedly improved hemodynamics, right ventricular (RV) hypertrophy, RV function, and arteriolar remodeling. When administered after the establishment of hemodynamically severe PH in a vasculoproliferative model, ACTRIIA-Fc was more effective than vasodilator in attenuating PH and arteriolar remodeling. Potent antiremodeling effects of ACTRIIA-Fc were associated with inhibition of SMAD2/3 activation and downstream transcriptional activity, inhibition of proliferation, and enhancement of apoptosis in the vascular wall. ACTRIIA-Fc reveals an unexpectedly prominent role of GDF8, GDF11, and activin as drivers of pulmonary vascular disease and represents a therapeutic strategy for restoring the balance between SMAD1/5/9 and SMAD2/3 signaling in PAH.
Topics: Activins; Animals; Cell Differentiation; Endothelial Cells; Hypertension, Pulmonary; Signal Transduction
PubMed: 32404506
DOI: 10.1126/scitranslmed.aaz5660 -
Nature Communications Jun 2021During early pregnancy in the mouse, nidatory estrogen (E2) stimulates endometrial receptivity by activating a network of signaling pathways that is not yet fully...
During early pregnancy in the mouse, nidatory estrogen (E2) stimulates endometrial receptivity by activating a network of signaling pathways that is not yet fully characterized. Here, we report that bone morphogenetic proteins (BMPs) control endometrial receptivity via a conserved activin receptor type 2 A (ACVR2A) and SMAD1/5 signaling pathway. Mice were generated to contain single or double conditional deletion of SMAD1/5 and ACVR2A/ACVR2B receptors using progesterone receptor (PR)-cre. Female mice with SMAD1/5 deletion display endometrial defects that result in the development of cystic endometrial glands, a hyperproliferative endometrial epithelium during the window of implantation, and impaired apicobasal transformation that prevents embryo implantation and leads to infertility. Analysis of Acvr2a-PRcre and Acvr2b-PRcre pregnant mice determined that BMP signaling occurs via ACVR2A and that ACVR2B is dispensable during embryo implantation. Therefore, BMPs signal through a conserved endometrial ACVR2A/SMAD1/5 pathway that promotes endometrial receptivity during embryo implantation.
Topics: Activin Receptors, Type II; Animals; Biopsy; Bone Morphogenetic Proteins; Disease Models, Animal; Embryo Implantation; Endometrium; Estrogens; Female; Humans; Infertility, Female; Mice; Mice, Knockout; Pregnancy; Signal Transduction; Smad1 Protein; Smad5 Protein
PubMed: 34099644
DOI: 10.1038/s41467-021-23571-5 -
Scientific Reports May 2022Sotatercept is an activin receptor type IIA-Fc (ActRIIA-Fc) fusion protein that improves cardiopulmonary function in patients with pulmonary arterial hypertension (PAH)...
Sotatercept is an activin receptor type IIA-Fc (ActRIIA-Fc) fusion protein that improves cardiopulmonary function in patients with pulmonary arterial hypertension (PAH) by selectively trapping activins and growth differentiation factors. However, the cellular and molecular mechanisms of ActRIIA-Fc action are incompletely understood. Here, we determined through genome-wide expression profiling that inflammatory and immune responses are prominently upregulated in the lungs of a Sugen-hypoxia rat model of severe angio-obliterative PAH, concordant with profiles observed in PAH patients. Therapeutic treatment with ActRIIA-Fc-but not with a vasodilator-strikingly reversed proinflammatory and proliferative gene expression profiles and normalized macrophage infiltration in diseased rodent lungs. Furthermore, ActRIIA-Fc normalized pulmonary macrophage infiltration and corrected cardiopulmonary structure and function in Bmpr2 haploinsufficient mice subjected to hypoxia, a model of heritable PAH. Three high-affinity ligands of ActRIIA-Fc each induced macrophage activation in vitro, and their combined immunoneutralization in PAH rats produced cardiopulmonary benefits comparable to those elicited by ActRIIA-Fc. Our results in complementary experimental and genetic models of PAH reveal therapeutic anti-inflammatory activities of ActRIIA-Fc that, together with its known anti-proliferative effects on vascular cell types, could underlie clinical activity of sotatercept as either monotherapy or add-on to current PAH therapies.
Topics: Animals; Disease Models, Animal; Familial Primary Pulmonary Hypertension; Humans; Hypertension, Pulmonary; Hypoxia; Inflammation; Mice; Pulmonary Arterial Hypertension; Rats; Recombinant Fusion Proteins
PubMed: 35551212
DOI: 10.1038/s41598-022-11435-x -
Immunity Feb 2021Th17 cells are known to exert pathogenic and non-pathogenic functions. Although the cytokine transforming growth factor β1 (TGF-β1) is instrumental for Th17 cell...
Th17 cells are known to exert pathogenic and non-pathogenic functions. Although the cytokine transforming growth factor β1 (TGF-β1) is instrumental for Th17 cell differentiation, it is dispensable for generation of pathogenic Th17 cells. Here, we examined the T cell-intrinsic role of Activin-A, a TGF-β superfamily member closely related to TGF-β1, in pathogenic Th17 cell differentiation. Activin-A expression was increased in individuals with relapsing-remitting multiple sclerosis and in mice with experimental autoimmune encephalomyelitis. Stimulation with interleukin-6 and Activin-A induced a molecular program that mirrored that of pathogenic Th17 cells and was inhibited by blocking Activin-A signaling. Genetic disruption of Activin-A and its receptor ALK4 in T cells impaired pathogenic Th17 cell differentiation in vitro and in vivo. Mechanistically, extracellular-signal-regulated kinase (ERK) phosphorylation, which was essential for pathogenic Th17 cell differentiation, was suppressed by TGF-β1-ALK5 but not Activin-A-ALK4 signaling. Thus, Activin-A drives pathogenic Th17 cell differentiation, implicating the Activin-A-ALK4-ERK axis as a therapeutic target for Th17 cell-related diseases.
Topics: Activin Receptors, Type I; Activins; Animals; Cell Differentiation; Cells, Cultured; Encephalomyelitis, Autoimmune, Experimental; Humans; Mice; Mice, Knockout; Molecular Targeted Therapy; Multiple Sclerosis; Neurogenic Inflammation; Signal Transduction; Th17 Cells; Transforming Growth Factor beta
PubMed: 33421362
DOI: 10.1016/j.immuni.2020.12.010 -
Proceedings of the National Academy of... Aug 2023Body fat distribution is a heritable risk factor for cardiovascular and metabolic disease. In humans, rare Inhibin beta E (, activin E) loss-of-function variants are...
Body fat distribution is a heritable risk factor for cardiovascular and metabolic disease. In humans, rare Inhibin beta E (, activin E) loss-of-function variants are associated with a lower waist-to-hip ratio and protection from type 2 diabetes. Hepatic fatty acid sensing promotes expression during fasting and in obese individuals, yet it is unclear how the hepatokine activin E governs body shape and energy metabolism. Here, we uncover activin E as a regulator of adipose energy storage. By suppressing β-agonist-induced lipolysis, activin E promotes fat accumulation and adipocyte hypertrophy and contributes to adipose dysfunction in mice. Mechanistically, we demonstrate that activin E elicits its effect on adipose tissue through ACVR1C, activating SMAD2/3 signaling and suppressing PPARG target genes. Conversely, loss of activin E or ACVR1C in mice increases fat utilization, lowers adiposity, and drives PPARG-regulated gene signatures indicative of healthy adipose function. Our studies identify activin E-ACVR1C as a metabolic rheostat promoting liver-adipose cross talk to restrain excessive fat breakdown and preserve fat mass during prolonged fasting, a mechanism that is maladaptive in obese individuals.
Topics: Humans; Mice; Animals; Lipolysis; Activins; Adiposity; Diabetes Mellitus, Type 2; PPAR gamma; Obesity; Adipose Tissue; Activin Receptors, Type I
PubMed: 37523551
DOI: 10.1073/pnas.2309967120 -
Science (New York, N.Y.) Sep 2020Vertebrates vary in their ability to regenerate, and the genetic mechanisms underlying such disparity remain elusive. Comparative epigenomic profiling and single-cell...
Vertebrates vary in their ability to regenerate, and the genetic mechanisms underlying such disparity remain elusive. Comparative epigenomic profiling and single-cell sequencing of two related teleost fish uncovered species-specific and evolutionarily conserved genomic responses to regeneration. The conserved response revealed several regeneration-responsive enhancers (RREs), including an element upstream to (), a known effector of vertebrate regeneration. This element activated expression in regenerating transgenic fish, and its genomic deletion perturbed caudal fin regeneration and abrogated cardiac regeneration altogether. The enhancer is present in mammals, shares functionally essential activator protein 1 (AP-1)-binding motifs, and responds to injury, but it cannot rescue regeneration in fish. This work suggests that changes in AP-1-enriched RREs are likely a crucial source of loss of regenerative capacities in vertebrates.
Topics: Amino Acid Motifs; Animals; Enhancer Elements, Genetic; Epigenesis, Genetic; Evolution, Molecular; Gene Expression Profiling; Histones; Inhibin-beta Subunits; Killifishes; RNA-Seq; Regeneration; Single-Cell Analysis; Transcription Factor AP-1; Transcriptional Activation; Zebrafish
PubMed: 32883834
DOI: 10.1126/science.aaz3090 -
Clinical Cancer Research : An Official... Sep 2023Cemiplimab is approved for the treatment of locally advanced basal cell carcinomas (BCC), although with mitigated results. We sought to interrogate the cellular and...
PURPOSE
Cemiplimab is approved for the treatment of locally advanced basal cell carcinomas (BCC), although with mitigated results. We sought to interrogate the cellular and molecular transcriptional reprogramming underlying BCC resistance to immunotherapy.
EXPERIMENTAL DESIGN
Here, we combined spatial and single-cell transcriptomics to deconvolute the spatial heterogeneity of the tumor microenvironment in regard with response to immunotherapy, in a cohort of both naïve and resistant BCCs.
RESULTS
We identified subsets of intermingled cancer-associated fibroblasts (CAF) and macrophages contributing the most to CD8 T-cell exclusion and immunosuppression. Within this spatially resolved peritumoral immunosuppressive niche, CAFs and adjacent macrophages were found to display Activin A-mediated transcriptional reprogramming towards extracellular matrix remodeling, suggesting active participation to CD8 T-cell exclusion. In independent datasets of human skin cancers, Activin A-conditioned CAFs and macrophages were associated with resistance to immune checkpoint inhibitors (ICI).
CONCLUSIONS
Altogether, our data identify the cellular and molecular plasticity of tumor microenvironment (TME) and the pivotal role of Activin A in polarizing the TME towards immune suppression and ICI resistance.
Topics: Humans; Cancer-Associated Fibroblasts; Skin Neoplasms; Carcinoma, Basal Cell; Macrophages; Immunotherapy; Tumor Microenvironment
PubMed: 37327314
DOI: 10.1158/1078-0432.CCR-23-0219 -
Hematology. American Society of... Dec 2021After years of reliance on transfusion alone to address anemia and suppress ineffective erythropoiesis in β-thalassemia, many new therapies are now in development.... (Review)
Review
After years of reliance on transfusion alone to address anemia and suppress ineffective erythropoiesis in β-thalassemia, many new therapies are now in development. Luspatercept, a transforming growth factor-β inhibitor, has demonstrated efficacy in reducing ineffective erythropoiesis, improving anemia, and possibly reducing iron loading. However, many patients do not respond to luspatercept, so additional therapeutics are needed. Several medications in development aim to induce hemoglobin F (HbF): sirolimus, benserazide, and IMR-687 (a phosphodiesterase 9 inhibitor). Another group of agents seeks to ameliorate ineffective erythropoiesis and improve anemia by targeting abnormal iron metabolism in thalassemia: apotransferrin, VIT-2763 (a ferroportin inhibitor), PTG-300 (a hepcidin mimetic), and an erythroferrone antibody in early development. Mitapivat, a pyruvate kinase activator, represents a unique mechanism to mitigate ineffective erythropoiesis. Genetically modified autologous hematopoietic stem cell transplantation offers the potential for lifelong transfusion independence. Through a gene addition approach, lentiviral vectors have been used to introduce a β-globin gene into autologous hematopoietic stem cells. One such product, betibeglogene autotemcel (beti-cel), has reached phase 3 trials with promising results. In addition, 2 gene editing techniques (CRISPR-Cas9 and zinc-finger nucleases) are under investigation as a means to silence BCL11A to induce HbF with agents designated CTX001 and ST-400, respectively. Results from the many clinical trials for these agents will yield results in the next few years, which may end the era of relying on transfusion alone as the mainstay of thalassemia therapy.
Topics: Activin Receptors, Type II; Adolescent; Adult; Blood Transfusion; Female; Hematinics; Hematopoietic Stem Cell Transplantation; Humans; Immunoglobulin Fc Fragments; Iron Chelating Agents; Male; Middle Aged; Recombinant Fusion Proteins; Young Adult; beta-Thalassemia
PubMed: 34889443
DOI: 10.1182/hematology.2021000313