Childs, CJ;Holloway, EM;Sweet, CW;Tsai, YH;Wu, A;Vallie, A;Eiken, MK;Capeling, MM;Zwick, RK;Palikuqi, B;Trentesaux, C;Wu, JH;Pellon-Cardenas, O;Zhang, CJ;Glass, IA;Loebel, C;Yu, Q;Camp, JG;Sexton, JZ;Klein, OD;Verzi, MP;Spence, JR;
PMID: 36821371 | DOI: 10.1172/jci.insight.165566
Epithelial organoids derived from intestinal tissue, called 'enteroids', recapitulate many aspects of the organ in vitro, and can be used for biological discovery, personalized medicine, and drug development. Here, we interrogated the cell signaling environment within the developing human intestine to identify niche cues that may be important for epithelial development and homeostasis. We identify an EGF family member, EPIREGULIN (EREG), which is robustly expressed in the developing human crypt. Enteroids generated from the developing human intestine grown in standard culture conditions, which contain EGF, are dominated by stem and progenitor cells, feature little differentiation and no spatial organization. Our results demonstrate that EREG can replace EGF in vitro, and EREG leads to spatially resolved enteroids that feature budded and proliferative crypt domains and a differentiated villus-like central lumen. Multiomic (transcriptome plus epigenome) profiling of native crypts, EGF-grown and EREG-grown enteroids show that EGF-enteroids have an altered chromatin landscape that is dependent on EGF concentration, downregulate the master intestinal transcription factor CDX2, and ectopically express stomach genes, a phenomenon that is reversible. This is in contrast to EREG-grown enteroids, which remain intestine-like in culture. Thus, EREG creates a homeostatic intestinal niche in vitro, enabling interrogation of stem cell function, cellular differentiation, and disease modeling.
Odontoblast death drives cell-rich zone-derived dental tissue regeneration
Zhao, L;Ito, S;Arai, A;Udagawa, N;Horibe, K;Hara, M;Nishida, D;Hosoya, A;Masuko, R;Okabe, K;Shin, M;Li, X;Matsuo, K;Abe, S;Matsunaga, S;Kobayashi, Y;Kagami, H;Mizoguchi, T;
PMID: 34020080 | DOI: 10.1016/j.bone.2021.116010
Severe dental tissue damage induces odontoblast death, after which dental pulp stem and progenitor cells (DPSCs) differentiate into odontoblast-like cells, contributing to reparative dentin. However, the damage-induced mechanism that triggers this regeneration process is still not clear. We aimed to understand the effect of odontoblast death without hard tissue damage on dental regeneration. Herein, using a Cre/LoxP-based strategy, we demonstrated that cell-rich zone (CZ)-localizing Nestin-GFP-positive and Nestin-GFP-negative cells proliferate and differentiate into odontoblast-like cells in response to odontoblast depletion. The regenerated odontoblast-like cells played a role in reparative dentin formation. RNA-sequencing analysis revealed that the expression of odontoblast differentiation- and activation-related genes was upregulated in the pulp in response to odontoblast depletion even without damage to dental tissue. In this regenerative process, the expression of type I parathyroid hormone receptor (PTH1R) increased in the odontoblast-depleted pulp, thereby boosting dentin formation. The levels of PTH1R and its downstream mediator, i.e., phosphorylated cyclic AMP response element-binding protein (Ser133) increased in the physically damaged pulp. Collectively, odontoblast death triggered the PTH1R cascade, which may represent a therapeutic target for inducing CZ-mediated dental regeneration.
Development (Cambridge, England)
Negretti, NM;Plosa, EJ;Benjamin, JT;Schuler, BA;Habermann, AC;Jetter, CS;Gulleman, P;Bunn, C;Hackett, AN;Ransom, M;Taylor, CJ;Nichols, D;Matlock, BK;Guttentag, SH;Blackwell, TS;Banovich, NE;Kropski, JA;Sucre, JMS;
PMID: 34927678 | DOI: 10.1242/dev.199512
Lung organogenesis requires precise timing and coordination to effect spatial organization and function of the parenchymal cells. To provide a systematic broad-based view of the mechanisms governing the dynamic alterations in parenchymal cells over crucial periods of development, we performed a single-cell RNA-sequencing time-series yielding 102,571 epithelial, endothelial and mesenchymal cells across nine time points from embryonic day 12 to postnatal day 14 in mice. Combining computational fate-likelihood prediction with RNA in situ hybridization and immunofluorescence, we explore lineage relationships during the saccular to alveolar stage transition. The utility of this publicly searchable atlas resource (www.sucrelab.org/lungcells) is exemplified by discoveries of the complexity of type 1 pneumocyte function and characterization of mesenchymal Wnt expression patterns during the saccular and alveolar stages - wherein major expansion of the gas-exchange surface occurs. We provide an integrated view of cellular dynamics in epithelial, endothelial and mesenchymal cell populations during lung organogenesis.
Arid1a-Plagl1-Hh signaling is indispensable for differentiation-associated cell cycle arrest of tooth root progenitors
Du, J;Jing, J;Yuan, Y;Feng, J;Han, X;Chen, S;Li, X;Peng, W;Xu, J;Ho, TV;Jiang, X;Chai, Y;
PMID: 33826897 | DOI: 10.1016/j.celrep.2021.108964
Chromatin remodelers often show broad expression patterns in multiple cell types yet can elicit cell-specific effects in development and diseases. Arid1a binds DNA and regulates gene expression during tissue development and homeostasis. However, it is unclear how Arid1a achieves its functional specificity in regulating progenitor cells. Using the tooth root as a model, we show that loss of Arid1a impairs the differentiation-associated cell cycle arrest of tooth root progenitors through Hedgehog (Hh) signaling regulation, leading to shortened roots. Our data suggest that Plagl1, as a co-factor, endows Arid1a with its cell-type/spatial functional specificity. Furthermore, we show that loss of Arid1a leads to increased expression of Arid1b, which is also indispensable for odontoblast differentiation but is not involved in regulation of Hh signaling. This study expands our knowledge of the intricate interactions among chromatin remodelers, transcription factors, and signaling molecules during progenitor cell fate determination and lineage commitment.
Arutyunyan, A;Roberts, K;Troulé, K;Wong, FCK;Sheridan, MA;Kats, I;Garcia-Alonso, L;Velten, B;Hoo, R;Ruiz-Morales, ER;Sancho-Serra, C;Shilts, J;Handfield, LF;Marconato, L;Tuck, E;Gardner, L;Mazzeo, CI;Li, Q;Kelava, I;Wright, GJ;Prigmore, E;Teichmann, SA;Bayraktar, OA;Moffett, A;Stegle, O;Turco, MY;Vento-Tormo, R;
PMID: 36991123 | DOI: 10.1038/s41586-023-05869-0
The relationship between the human placenta-the extraembryonic organ made by the fetus, and the decidua-the mucosal layer of the uterus, is essential to nurture and protect the fetus during pregnancy. Extravillous trophoblast cells (EVTs) derived from placental villi infiltrate the decidua, transforming the maternal arteries into high-conductance vessels1. Defects in trophoblast invasion and arterial transformation established during early pregnancy underlie common pregnancy disorders such as pre-eclampsia2. Here we have generated a spatially resolved multiomics single-cell atlas of the entire human maternal-fetal interface including the myometrium, which enables us to resolve the full trajectory of trophoblast differentiation. We have used this cellular map to infer the possible transcription factors mediating EVT invasion and show that they are preserved in in vitro models of EVT differentiation from primary trophoblast organoids3,4 and trophoblast stem cells5. We define the transcriptomes of the final cell states of trophoblast invasion: placental bed giant cells (fused multinucleated EVTs) and endovascular EVTs (which form plugs inside the maternal arteries). We predict the cell-cell communication events contributing to trophoblast invasion and placental bed giant cell formation, and model the dual role of interstitial EVTs and endovascular EVTs in mediating arterial transformation during early pregnancy. Together, our data provide a comprehensive analysis of postimplantation trophoblast differentiation that can be used to inform the design of experimental models of the human placenta in early pregnancy.
Liang, T;Hu, Y;Zhang, H;Xu, Q;Smith, CE;Zhang, C;Kim, JW;Wang, SK;Saunders, TL;Lu, Y;Hu, JC;Simmer, JP;
PMID: 34667213 | DOI: 10.1038/s41598-021-00219-4
Non-syndromic inherited defects of tooth dentin are caused by two classes of dominant negative/gain-of-function mutations in dentin sialophosphoprotein (DSPP): 5' mutations affecting an N-terminal targeting sequence and 3' mutations that shift translation into the - 1 reading frame. DSPP defects cause an overlapping spectrum of phenotypes classified as dentin dysplasia type II and dentinogenesis imperfecta types II and III. Using CRISPR/Cas9, we generated a Dspp-1fs mouse model by introducing a FLAG-tag followed by a single nucleotide deletion that translated 493 extraneous amino acids before termination. Developing incisors and/or molars from this mouse and a DsppP19L mouse were characterized by morphological assessment, bSEM, nanohardness testing, histological analysis, in situ hybridization and immunohistochemistry. DsppP19L dentin contained dentinal tubules but grew slowly and was softer and less mineralized than the wild-type. DsppP19L incisor enamel was softer than normal, while molar enamel showed reduced rod/interrod definition. Dspp-1fs dentin formation was analogous to reparative dentin: it lacked dentinal tubules, contained cellular debris, and was significantly softer and thinner than Dspp+/+ and DsppP19L dentin. The Dspp-1fs incisor enamel appeared normal and was comparable to the wild-type in hardness. We conclude that 5' and 3' Dspp mutations cause dental malformations through different pathological mechanisms and can be regarded as distinct disorders.
Arid1a regulates cell cycle exit of transit-amplifying cells by inhibiting the Aurka-Cdk1 axis in mouse incisor
Development (Cambridge, England)
Du, J;Jing, J;Chen, S;Yuan, Y;Feng, J;Ho, TV;Sehgal, P;Xu, J;Jiang, X;Chai, Y;
PMID: 33766930 | DOI: 10.1242/dev.198838
Stem cells self-renew or give rise to transit-amplifying cells (TACs) that differentiate into specific functional cell types. The fate determination of stem cells to TACs and their transition to fully differentiated progeny is precisely regulated to maintain tissue homeostasis. Arid1a, a core component of the switch/sucrose nonfermentable complex, performs epigenetic regulation of stage- and tissue-specific genes that is indispensable for stem cell homeostasis and differentiation. However, the functional mechanism of Arid1a in the fate commitment of mesenchymal stem cells (MSCs) and their progeny is not clear. Using the continuously growing adult mouse incisor model, we show that Arid1a maintains tissue homeostasis through limiting proliferation, promoting cell cycle exit and differentiation of TACs by inhibiting the Aurka-Cdk1 axis. Loss of Arid1a overactivates the Aurka-Cdk1 axis, leading to expansion of the mitotic TAC population but compromising their differentiation ability. Furthermore, the defective homeostasis after loss of Arid1a ultimately leads to reduction of the MSC population. These findings reveal the functional significance of Arid1a in regulating the fate of TACs and their interaction with MSCs to maintain tissue homeostasis.