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.
Reactivation of the Hedgehog pathway in esophageal progenitors turns on an embryonic-like program to initiate columnar metaplasia
Vercauteren Drubbel, A;Pirard, S;Kin, S;Dassy, B;Lefort, A;Libert, F;Nomura, S;Beck, B;
PMID: 33882290 | DOI: 10.1016/j.stem.2021.03.019
Columnar metaplasia of the esophagus is the main risk factor for esophageal adenocarcinoma. There is a lack of evidence to demonstrate that esophageal progenitors can be the source of columnar metaplasia. In this study, using transgenic mouse models, lineage tracing, single-cell RNA sequencing, and transcriptomic and epigenetic profiling, we found that the activation of the Hedgehog pathway in esophageal cells modifies their differentiation status in vivo. This process involves an initial step of dedifferentiation into embryonic-like esophageal progenitors. Moreover, a subset of these cells undergoes full squamous-to-columnar conversion and expresses selected intestinal markers. These modifications of cell fate are associated with remodeling of the chromatin and the appearance of Sox9. Using a conditional knockout mouse, we show that Sox9 is required for columnar conversion but not for the step of dedifferentiation. These results provide insight into the mechanisms by which esophageal cells might initiate columnar metaplasia.
Giovannone D, Paul S, Schindler S, Arata C, Farmer DT, Patel P, Smeeton J, Crump JG.
PMID: 30785394 | DOI: 10.7554/eLife.42736
Much of the vertebrate skeleton develops from cartilage templates that are progressively remodeled into bone. Lineage tracing studies in mouse suggest that chondrocytes within these templates persist and become osteoblasts, yet the underlying mechanisms of this process and whether chondrocytes can generate other derivatives remain unclear. We find that zebrafish cartilages undergo extensive remodeling and vascularization during juvenile stages to generate fat-filled bones. Growth plate chondrocytes marked by sox10 and col2a1a contribute to osteoblasts, marrow adipocytes, and mesenchymal cells within adult bones. At the edge of the hypertrophic zone, chondrocytes re-enter the cell cycle and express leptin receptor (lepr), suggesting conversion into progenitors. Further, mutation of matrix metalloproteinase 9 (mmp9) results in delayed growth plate remodeling and fewer marrow adipocytes. Our data support Mmp9-dependent growth plate remodeling and conversion of chondrocytes into osteoblasts and marrow adipocytes as conserved features of bony vertebrates.
Pandey PR, Yang JH, Tsitsipatis D, Panda AC, Noh JH, Kim KM, Munk R, Nicholson T, Hanniford D, Argibay D, Yang X, Martindale JL, Chang MW, Jones SW, Hernando E, Sen P, De S, Abdelmohsen K, Gorospe M
PMID: 31980816 | DOI: 10.1093/nar/gkaa035
By interacting with proteins and nucleic acids, the vast family of mammalian circRNAs is proposed to influence many biological processes. Here, RNA sequencing analysis of circRNAs differentially expressed during myogenesis revealed that circSamd4 expression increased robustly in mouse C2C12 myoblasts differentiating into myotubes. Moreover, silencing circSamd4, which is conserved between human and mouse, delayed myogenesis and lowered the expression of myogenic markers in cultured myoblasts from both species. Affinity pulldown followed by mass spectrometry revealed that circSamd4 associated with PURA and PURB, two repressors of myogenesis that inhibit transcription of the myosin heavy chain (MHC) protein family. Supporting the hypothesis that circSamd4 might complex with PUR proteins and thereby prevent their interaction with DNA, silencing circSamd4 enhanced the association of PUR proteins with the Mhc promoter, while overexpressing circSamd4 interfered with the binding of PUR proteins to the Mhc promoter. These effects were abrogated when using a mutant circSamd4 lacking the PUR binding site. Our results indicate that the association of PUR proteins with circSamd4 enhances myogenesis by contributing to the derepression of MHC transcription
Marg A, Escobar H, Karaiskos N, Grunwald SA, Metzler E, Kieshauer J, Sauer S, Pasemann D, Malfatti E Mompoint D, Quijano-Roy S, Boltengagen A, Schneider J, Sch�lke M, Kunz S, Carlier R, Birchmeier C, Amthor H Spuler A, Kocks C, Rajewsky N, Spuler S
PMID: 31852888 | DOI: 10.1038/s41467-019-13650-z
Skeletal muscle stem cells, called satellite cells and defined by the transcription factor PAX7, are responsible for postnatal muscle growth, homeostasis and regeneration. Attempts to utilize the regenerative potential of muscle stem cells for therapeutic purposes so far failed. We previously established the existence of human PAX7-positive cell colonies with high regenerative potential. We now identified PAX7-negative human muscle-derived cell colonies also positive for the myogenic markers desmin and MYF5. These include cells from a patient with a homozygous PAX7 c.86-1G?>?A mutation (PAX7null). Single cell and bulk transcriptome analysis show high intra- and inter-donor heterogeneity and reveal the endothelial cell marker CLEC14A to be highly expressed in PAX7null cells. All PAX7-negative cell populations, including PAX7null, form myofibers after transplantation into mice, and regenerate muscle after reinjury. Transplanted PAX7neg cells repopulate the satellite cell niche where they re-express PAX7, or, strikingly, CLEC14A. In conclusion, transplanted human cells do not depend on PAX7 for muscle regeneration.
Yang Loureiro, Z;Joyce, S;DeSouza, T;Solivan-Rivera, J;Desai, A;Skritakis, P;Yang, Q;Ziegler, R;Zhong, D;Nguyen, TT;MacDougald, OA;Corvera, S;
PMID: 37337125 | DOI: 10.1038/s42255-023-00813-y
Mesenchymal stem/progenitor cells are essential for tissue development and repair throughout life, but how they are maintained under chronic differentiation pressure is not known. Using single-cell transcriptomics of human progenitor cells we find that adipose differentiation stimuli elicit two cellular trajectories: one toward mature adipocytes and another toward a pool of non-differentiated cells that maintain progenitor characteristics. These cells are induced by transient Wnt pathway activation and express numerous extracellular matrix genes and are therefore named structural Wnt-regulated adipose tissue cells. We find that the genetic signature of structural Wnt-regulated adipose tissue cells is present in adult human adipose tissue and adipose tissue developed from human progenitor cells in mice. Our results suggest a mechanism whereby adipose differentiation occurs concurrently with the maintenance of a mesenchymal progenitor cell pool, ensuring tissue development, repair and appropriate metabolic control over the lifetime.
Andersen, J;Thom, N;Shadrach, JL;Chen, X;Onesto, MM;Amin, ND;Yoon, SJ;Li, L;Greenleaf, WJ;Müller, F;Pașca, AM;Kaltschmidt, JA;Pașca, SP;
PMID: 37095394 | DOI: 10.1038/s41593-023-01311-w
Understanding spinal cord assembly is essential to elucidate how motor behavior is controlled and how disorders arise. The human spinal cord is exquisitely organized, and this complex organization contributes to the diversity and intricacy of motor behavior and sensory processing. But how this complexity arises at the cellular level in the human spinal cord remains unknown. Here we transcriptomically profiled the midgestation human spinal cord with single-cell resolution and discovered remarkable heterogeneity across and within cell types. Glia displayed diversity related to positional identity along the dorso-ventral and rostro-caudal axes, while astrocytes with specialized transcriptional programs mapped into white and gray matter subtypes. Motor neurons clustered at this stage into groups suggestive of alpha and gamma neurons. We also integrated our data with multiple existing datasets of the developing human spinal cord spanning 22 weeks of gestation to investigate the cell diversity over time. Together with mapping of disease-related genes, this transcriptomic mapping of the developing human spinal cord opens new avenues for interrogating the cellular basis of motor control in humans and guides human stem cell-based models of disease.
bioRxiv : the preprint server for biology
Bao, L;Fu, L;Su, Y;Chen, Z;Peng, Z;Sun, L;Gonzalez, FJ;Wu, C;Zhang, H;Shi, B;Shi, YB;
PMID: 36789439 | DOI: 10.1101/2023.01.24.524966
The intestine is critical for not only processing and resorbing nutrients but also protecting the organism from the environment. These functions are mainly carried out by the epithelium, which is constantly being self-renewed. Many genes and pathways can influence intestinal epithelial cell proliferation. Among them is mTORC1, whose activation increases cell proliferation. Here, we report the first intestinal epithelial cell-specific knockout ( ΔIEC ) of an amino acid transporter capable of activating mTORC1. We show that the transporter, SLC7A5, is highly expressed in mouse intestinal crypt and Slc7a5 ΔIEC reduces mTORC1 signaling. Surprisingly, Slc7a5 ΔIEC mice have increased cell proliferation but reduced secretory cells, particularly mature Paneth cells. scRNA-seq and electron microscopic analyses revealed dedifferentiation of Paneth cells in Slc7a5 ΔIEC mice, leading to markedly reduced secretory granules with little effect on Paneth cell number. We further show that Slc7a5 ΔIEC mice are prone to experimental colitis. Thus, SLC7A5 regulates secretory cell differentiation to affect stem cell niche and/or inflammatory response to regulate cell proliferation.
Martino, P;Sunkara, R;Heitman, N;Rangl, M;Brown, A;Saxena, N;Grisanti, L;Kohan, D;Yanagisawa, M;Rendl, M;
PMID: 36717629 | DOI: 10.1038/s41556-022-01065-w
Substantial follicle remodelling during the regression phase of the hair growth cycle is coordinated by the contraction of the dermal sheath smooth muscle, but how dermal-sheath-generated forces are regulated is unclear. Here, we identify spatiotemporally controlled endothelin signalling-a potent vasoconstriction-regulating pathway-as the key activating mechanism of dermal sheath contraction. Pharmacological blocking or genetic ablation of both endothelin receptors, ETA and ETB, impedes dermal sheath contraction and halts follicle regression. Epithelial progenitors at the club hair-epithelial strand bottleneck produce the endothelin ligand ET-1, which is required for follicle regression. ET signalling in dermal sheath cells and downstream contraction is dynamically regulated by cytoplasmic Ca2+ levels through cell membrane and sarcoplasmic reticulum calcium channels. Together, these findings illuminate an epithelial-mesenchymal interaction paradigm in which progenitors-destined to undergo programmed cell death-control the contraction of the surrounding sheath smooth muscle to orchestrate homeostatic tissue regression and reorganization for the next stem cell activation and regeneration cycle.
Hu, H;Duan, Y;Wang, K;Fu, H;Liao, Y;Wang, T;Zhang, Z;Kang, F;Zhang, B;Zhang, H;Huo, F;Yin, Y;Chen, G;Hu, H;Cai, H;Tian, W;Li, Z;
PMID: 36476878 | DOI: 10.1016/j.celrep.2022.111737
Mammalian teeth develop from the inductive epithelial-mesenchymal interaction, an important mechanism shared by many organs. The cellular basis for such interaction remains elusive. Here, we generate a dual-fluorescence model to track and analyze dental cells from embryonic to postnatal stages, in which Pitx2+ epithelium and Msx1+ mesenchyme are sufficient for tooth reconstitution. Single-cell RNA sequencing and spatial mapping further revealed critical cellular dynamics during molar development, where tooth germs are organized by Msx1+Sdc1+ dental papilla and surrounding dental niche. Surprisingly, niche cells are more efficient in tooth reconstitution and can directly regenerate papilla cells through interaction with dental epithelium. Finally, from the dental niche, we identify a group of previously unappreciated migratory Msx1+ Sox9+ cells as the potential cell origin for dental papilla. Our results indicate that the dental niche cells directly contribute to tooth organogenesis and provide critical insights into the essential cell composition for tooth engineering.
Pezoldt, J;Wiechers, C;Zou, M;Litovchenko, M;Biocanin, M;Beckstette, M;Sitnik, K;Palatella, M;van Mierlo, G;Chen, W;Gardeux, V;Floess, S;Ebel, M;Russeil, J;Arampatzi, P;Vafardanejad, E;Saliba, AE;Deplancke, B;Huehn, J;
PMID: 36433946 | DOI: 10.1038/s41467-022-34868-4
Gut-draining mesenteric lymph nodes (LN) provide the framework to shape intestinal adaptive immune responses. Based on the transcriptional signatures established by our previous work, the composition and immunomodulatory function of LN stromal cells (SC) vary according to location. Here, we describe the single-cell composition and development of the SC compartment within mesenteric LNs derived from postnatal to aged mice. We identify CD34+ SC and fibroblastic reticular stromal cell (FRC) progenitors as putative progenitors, both supplying the typical rapid postnatal mesenteric LN expansion. We further establish the location-specific chromatin accessibility and DNA methylation landscape of non-endothelial SCs and identify a microbiota-independent core epigenomic signature, showing characteristic differences between SCs from mesenteric and skin-draining peripheral LNs. The epigenomic landscape of SCs points to dynamic expression of Irf3 along the differentiation trajectories of FRCs. Accordingly, a mesenchymal stem cell line acquires a Cxcl9+ FRC molecular phenotype upon lentiviral overexpression of Irf3, and the relevance of Irf3 for SC biology is further underscored by the diminished proportion of Ccl19+ and Cxcl9+ FRCs in LNs of Irf3-/- mice. Together, our data constitute a comprehensive transcriptional and epigenomic map of mesenteric LNSC development in early life and dissect location-specific, microbiota-independent properties of non-endothelial SCs.
Shi, X;Zhuang, Y;Chen, Z;Xu, M;Kuang, J;Sun, XL;Gao, L;Kuang, X;Zhang, H;Li, W;Wong, SZH;Liu, C;Liu, L;Jiang, D;Pei, D;Lin, Y;Wu, QF;
PMID: 36383654 | DOI: 10.1126/sciadv.abq2987
The neuroendocrine system consists of a heterogeneous collection of neuropeptidergic neurons in the brain, among which hypothalamic KNDy neurons represent an indispensable cell subtype controlling puberty onset. Although neural progenitors and neuronal precursors along the cell lineage hierarchy adopt a cascade diversification strategy to generate hypothalamic neuronal heterogeneity, the cellular logic operating within the lineage to specify a subtype of neuroendocrine neurons remains unclear. As human genetic studies have recently established a link between TBX3 mutations and delayed puberty onset, we systematically studied Tbx3-derived neuronal lineage and Tbx3-dependent neuronal specification and found that Tbx3 hierarchically established and maintained the identity of KNDy neurons for triggering puberty. Apart from the well-established lineage-dependent fate determination, we uncovered rules of interlineage interaction and intralineage retention operating through neuronal differentiation in the absence of Tbx3. Moreover, we revealed that human TBX3 mutations disturbed the phase separation of encoded proteins and impaired transcriptional regulation of key neuropeptides, providing a pathological mechanism underlying TBX3-associated puberty disorders.
