Mutation in the Ciliary Protein C2CD3 Reveals Organ-Specific Mechanisms of Hedgehog Signal Transduction in Avian Embryos
Journal of Developmental Biology
Brooks, E;Bonatto Paese, C;Carroll, A;Struve, J;Nagy, N;Brugmann, S;
| DOI: 10.3390/jdb9020012
Primary cilia are ubiquitous microtubule-based organelles that serve as signaling hubs for numerous developmental pathways, most notably the Hedgehog (Hh) pathway. Defects in the structure or function of primary cilia result in a class of diseases called ciliopathies. It is well known that primary cilia participate in transducing a Hh signal, and as such ciliopathies frequently present with phenotypes indicative of aberrant Hh function. Interestingly, the exact mechanisms of cilia-dependent Hh signaling transduction are unclear as some ciliopathic animal models simultaneously present with gain-of-Hh phenotypes in one organ system and loss-of-Hh phenotypes in another. To better understand how Hh signaling is perturbed across different tissues in ciliopathic conditions, we examined four distinct Hh-dependent signaling centers in the naturally occurring avian ciliopathic mutant talpid2 (ta2). In addition to the well-known and previously reported limb and craniofacial malformations, we observed dorsal-ventral patterning defects in the neural tube, and a shortened gastrointestinal tract. Molecular analyses for elements of the Hh pathway revealed that the loss of cilia impact transduction of an Hh signal in a tissue-specific manner at variable levels of the pathway. These studies will provide increased knowledge into how impaired ciliogenesis differentially regulates Hh signaling across tissues and will provide potential avenues for future targeted therapeutic treatments.
WNT signaling in pre-granulosa cells is required for ovarian folliculogenesis and female fertility
Development (Cambridge, England)
Habara, O;Logan, CY;Kanai-Azuma, M;Nusse, R;Takase, HM;
PMID: 33914868 | DOI: 10.1242/dev.198846
In mammalian ovaries, immature oocytes are reserved in primordial follicles until their activation for potential ovulation. Precise control of primordial follicle activation (PFA) is essential for reproduction, but how this is achieved is unclear. Here, we show that canonical wingless-type MMTV integration site family (WNT) signaling is pivotal for pre-granulosa cell (pre-GC) activation during PFA. We identified several WNT ligands expressed in pre-GCs that act in an autocrine manner. Inhibition of WNT secretion from pre-GCs/GCs by conditional knockout (cKO) of the wntless (Wls) gene led to female infertility. In Wls cKO mice, GC layer thickness was greatly reduced in growing follicles, which resulted in impaired oocyte growth with both an abnormal, sustained nuclear localization of forkhead box O3 (FOXO3) and reduced phosphorylation of ribosomal protein S6 (RPS6). Constitutive stabilization of β-catenin (CTNNB1) in pre-GCs/GCs induced morphological changes of pre-GCs from a squamous into a cuboidal form, though it did not influence oocyte activation. Our results reveal that canonical WNT signaling plays a permissive role in the transition of pre-GCs to GCs, which is an essential step to support oocyte growth.
International journal of molecular sciences
Belgacemi, R;Danopoulos, S;Deutsch, G;Glass, I;Dormoy, V;Bellusci, S;Al Alam, D;
PMID: 35563656 | DOI: 10.3390/ijms23095265
The Hedgehog (HH) signaling pathway plays an essential role in mouse lung development. We hypothesize that the HH pathway is necessary for branching during human lung development and is impaired in pulmonary hypoplasia. Single-cell, bulk RNA-sequencing data, and human fetal lung tissues were analyzed to determine the spatiotemporal localization of HH pathway actors. Distal human lung segments were cultured in an air-liquid interface and treated with an SHH inhibitor (5E1) to determine the effect of HH inhibition on human lung branching, epithelial-mesenchymal markers, and associated signaling pathways in vitro. Our results showed an early and regulated expression of HH pathway components during human lung development. Inhibiting HH signaling caused a reduction in branching during development and dysregulated epithelial (SOX2, SOX9) and mesenchymal (ACTA2) progenitor markers. FGF and Wnt pathways were also disrupted upon HH inhibition. Finally, we demonstrated that HH signaling elements were downregulated in lung tissues of patients with a congenital diaphragmatic hernia (CDH). In this study, we show for the first time that HH signaling inhibition alters important genes and proteins required for proper branching of the human developing lung. Understanding the role of the HH pathway on human lung development could lead to the identification of novel therapeutic targets for childhood pulmonary diseases.
Cellular and molecular gastroenterology and hepatology
Zhu, S;Rao, X;Qian, Y;Chen, J;Song, R;Yan, H;Yang, X;Hu, J;Wang, X;Han, Z;Zhu, Y;Liu, R;Jong-Leong Wong, J;McCaughan, GW;Zheng, X;
PMID: 35202885 | DOI: 10.1016/j.jcmgh.2022.02.010
The liver has complex interconnecting blood vessel and biliary networks, however how the vascular and biliary network form and regulate each other and liver function are not well understood. We aimed to examine the role of Heg in mammalian liver development and functional maintenance.Global (Heg-/-) or liver endothelial cell-specific deletion of Heg (Lyve1-Cre;Hegfl/fl ) mice were used to study the in vivo function of Heg in the liver. Carbon-ink anterograde and retrograde injection were used to visualize the 3-D patterning of liver portal and biliary networks, respectively. RNA sequencing, histology, molecular and biochemical assays were used to assess liver gene expression, protein distribution, liver injury response and function.Heg deficiency in liver endothelial cells led to a sparse liver vascular and biliary network. This network paucity does not compromise liver function under baseline conditions but did alter liver zonation. Molecular analysis revealed that endothelial Heg deficiency decreased expression of Wnt ligands/agonists including Wnt2, Wnt9b and Rspo3 in endothelial cells, which limits Axin2 mediated canonical Wnt signaling and the expression of cytochrome P450 enzymes in hepatocytes. Under chemical-induced stressed conditions, Heg-deficiency in liver endothelial cells protected mice from drug-induced liver injuries.Our study found that endothelial Heg is essential for the 3-D patterning of the liver vascular and indirectly regulates biliary networks and proper liver zonation via its regulation of Wnt ligand production in liver endothelial cells. The endothelial Heg-initiated changes of the liver metabolic zonation and metabolic enzyme expression in hepatocytes was functionally relevant to xenobiotic metabolism and drug induced liver toxicity.
Kaucka, M;Joven Araus, A;Tesarova, M;Currie, JD;Boström, J;Kavkova, M;Petersen, J;Yao, Z;Bouchnita, A;Hellander, A;Zikmund, T;Elewa, A;Newton, PT;Fei, JF;Chagin, AS;Fried, K;Tanaka, EM;Kaiser, J;Simon, A;Adameyko, I;
PMID: 36376278 | DOI: 10.1038/s41467-022-34266-w
There are major differences in duration and scale at which limb development and regeneration proceed, raising the question to what extent regeneration is a recapitulation of development. We address this by analyzing skeletal elements using a combination of micro-CT imaging, molecular profiling and clonal cell tracing. We find that, in contrast to development, regenerative skeletal growth is accomplished based entirely on cartilage expansion prior to ossification, not limiting the transversal cartilage expansion and resulting in bulkier skeletal parts. The oriented extension of salamander cartilage and bone appear similar to the development of basicranial synchondroses in mammals, as we found no evidence for cartilage stem cell niches or growth plate-like structures during neither development nor regeneration. Both regenerative and developmental ossification in salamanders start from the cortical bone and proceeds inwards, showing the diversity of schemes for the synchrony of cortical and endochondral ossification among vertebrates.
Tracing the origin of hair follicle stem cells
Morita, R;Sanzen, N;Sasaki, H;Hayashi, T;Umeda, M;Yoshimura, M;Yamamoto, T;Shibata, T;Abe, T;Kiyonari, H;Furuta, Y;Nikaido, I;Fujiwara, H;
PMID: 34108685 | DOI: 10.1038/s41586-021-03638-5
Tissue stem cells are generated from a population of embryonic progenitors through organ-specific morphogenetic events1,2. Although tissue stem cells are central to organ homeostasis and regeneration, it remains unclear how they are induced during development, mainly because of the lack of markers that exclusively label prospective stem cells. Here we combine marker-independent long-term 3D live imaging and single-cell transcriptomics to capture a dynamic lineage progression and transcriptome changes in the entire epithelium of the mouse hair follicle as it develops. We found that the precursors of different epithelial lineages were aligned in a 2D concentric manner in the basal layer of the hair placode. Each concentric ring acquired unique transcriptomes and extended to form longitudinally aligned, 3D cylindrical compartments. Prospective bulge stem cells were derived from the peripheral ring of the placode basal layer, but not from suprabasal cells (as was previously suggested3). The fate of placode cells is determined by the cell position, rather than by the orientation of cell division. We also identified 13 gene clusters: the ensemble expression dynamics of these clusters drew the entire transcriptional landscape of epithelial lineage diversification, consistent with cell lineage data. Combining these findings with previous work on the development of appendages in insects4,5, we describe the 'telescope model', a generalized model for the development of ectodermal organs in which 2D concentric zones in the placode telescope out to form 3D longitudinally aligned cylindrical compartments.
Gao, F;Li, C;Danopoulos, S;Al Alam, D;Peinado, N;Webster, S;Borok, Z;Kohbodi, GA;Bellusci, S;Minoo, P;
PMID: 35385750 | DOI: 10.1016/j.celrep.2022.110608
The lung alveolus is lined with alveolar type 1 (AT1) and type 2 (AT2) epithelial cells. During alveologenesis, increasing demand associated with expanding alveolar numbers is met by proliferating progenitor AT2s (pAT2). Little information exists regarding the identity of this population and their niche microenvironment. We show that during alveologenesis, Hedgehog-responsive PDGFRa(+) progenitors (also known as SCMFs) are a source of secreted trophic molecules that maintain a unique pAT2 population. SCMFs are in turn maintained by TGFβ signaling. Compound inactivation of Alk5 TβR2 in SCMFs reduced their numbers and depleted the pAT2 pool without impacting differentiation of daughter cells. In lungs of preterm infants who died with bronchopulmonary dysplasia, PDGFRa is reduced and the number of proliferative AT2s is diminished, indicating that an evolutionarily conserved mechanism governs pAT2 behavior during alveologenesis. SCMFs are a transient cell population, active only during alveologenesis, making them a unique stage-specific niche mesodermal cell type in mammalian organs.
Kishimoto, K;Iwasawa, K;Sorel, A;Ferran-Heredia, C;Han, L;Morimoto, M;Wells, JM;Takebe, T;Zorn, AM;
PMID: 35978039 | DOI: 10.1038/s41596-022-00733-3
Development of visceral organs such as the esophagus, lung, liver and stomach are coordinated by reciprocal signaling interactions between the endoderm and adjacent mesoderm cells in the fetal foregut. Although the recent successes in recapitulating developmental signaling in vitro has enabled the differentiation of human pluripotent stem cells (hPSCs) into various types of organ-specific endodermal epithelium, the generation of organ-specific mesenchyme has received much less attention. This is a major limitation in ongoing efforts to engineer complex human tissue. Here, we describe a protocol to differentiate hPSCs into different types of organ-specific mesoderm, leveraging signaling networks and molecular markers elucidated from single-cell transcriptomics of mouse foregut organogenesis. Building on established methods, hPSC-derived lateral plate mesoderm treated with either retinoic acid (RA) or RA together with a Hedgehog (HH) agonist generates posterior or anterior foregut splanchnic mesoderm, respectively, after 4-d cultures. These are directed into organ-specific mesenchyme lineages by the combinatorial activation or inhibition of WNT, BMP, RA or HH pathways from days 4 to 7 in cultures. By day 7, the cultures are enriched for different types of mesoderm with distinct molecular signatures: 60-90% pure liver septum transversum/mesothelium-like, 70-80% pure liver-like fibroblasts and populations of ~35% respiratory-like mesoderm, gastric-like mesoderm or esophageal-like mesoderm. This protocol can be performed by anyone with moderate experience differentiating hPSCs, provides a novel platform to study human mesoderm development and can be used to engineer more complex foregut tissue for disease modeling and regenerative medicine.
Hein, RFC;Wu, JH;Holloway, EM;Frum, T;Conchola, AS;Tsai, YH;Wu, A;Fine, AS;Miller, AJ;Szenker-Ravi, E;Yan, KS;Kuo, CJ;Glass, I;Reversade, B;Spence, JR;
PMID: 35679862 | DOI: 10.1016/j.devcel.2022.05.010
The human respiratory epithelium is derived from a progenitor cell in the distal buds of the developing lung. These "bud tip progenitors" are regulated by reciprocal signaling with surrounding mesenchyme; however, mesenchymal heterogeneity and function in the developing human lung are poorly understood. We interrogated single-cell RNA sequencing data from multiple human lung specimens and identified a mesenchymal cell population present during development that is highly enriched for expression of the WNT agonist RSPO2, and we found that the adjacent bud tip progenitors are enriched for the RSPO2 receptor LGR5. Functional experiments using organoid models, explant cultures, and FACS-isolated RSPO2+ mesenchyme show that RSPO2 is a critical niche cue that potentiates WNT signaling in bud tip progenitors to support their maintenance and multipotency.
Glover, JD;Sudderick, ZR;Shih, BB;Batho-Samblas, C;Charlton, L;Krause, AL;Anderson, C;Riddell, J;Balic, A;Li, J;Klika, V;Woolley, TE;Gaffney, EA;Corsinotti, A;Anderson, RA;Johnston, LJ;Brown, SJ;Wang, S;Chen, Y;Crichton, ML;Headon, DJ;
PMID: 36764291 | DOI: 10.1016/j.cell.2023.01.015
Fingerprints are complex and individually unique patterns in the skin. Established prenatally, the molecular and cellular mechanisms that guide fingerprint ridge formation and their intricate arrangements are unknown. Here we show that fingerprint ridges are epithelial structures that undergo a truncated hair follicle developmental program and fail to recruit a mesenchymal condensate. Their spatial pattern is established by a Turing reaction-diffusion system, based on signaling between EDAR, WNT, and antagonistic BMP pathways. These signals resolve epithelial growth into bands of focalized proliferation under a precociously differentiated suprabasal layer. Ridge formation occurs as a set of waves spreading from variable initiation sites defined by the local signaling environments and anatomical intricacies of the digit, with the propagation and meeting of these waves determining the type of pattern that forms. Relying on a dynamic patterning system triggered at spatially distinct sites generates the characteristic types and unending variation of human fingerprint patterns.
Charting human development using a multi-endodermal organ atlas and organoid models
Yu, Q;Kilik, U;Holloway, EM;Tsai, YH;Harmel, C;Wu, A;Wu, JH;Czerwinski, M;Childs, CJ;He, Z;Capeling, MM;Huang, S;Glass, IA;Higgins, PDR;Treutlein, B;Spence, JR;Camp, JG;
PMID: 34019796 | DOI: 10.1016/j.cell.2021.04.028
Organs are composed of diverse cell types that traverse transient states during organogenesis. To interrogate this diversity during human development, we generate a single-cell transcriptome atlas from multiple developing endodermal organs of the respiratory and gastrointestinal tract. We illuminate cell states, transcription factors, and organ-specific epithelial stem cell and mesenchyme interactions across lineages. We implement the atlas as a high-dimensional search space to benchmark human pluripotent stem cell (hPSC)-derived intestinal organoids (HIOs) under multiple culture conditions. We show that HIOs recapitulate reference cell states and use HIOs to reconstruct the molecular dynamics of intestinal epithelium and mesenchyme emergence. We show that the mesenchyme-derived niche cue NRG1 enhances intestinal stem cell maturation in vitro and that the homeobox transcription factor CDX2 is required for regionalization of intestinal epithelium and mesenchyme in humans. This work combines cell atlases and organoid technologies to understand how human organ development is orchestrated.