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.
Walter, RJ;Sonnentag, SJ;Munoz-Sagredo, L;Merkel, M;Richert, L;Bunert, F;Heneka, YM;Loustau, T;Hodder, M;Ridgway, RA;Sansom, OJ;Mely, Y;Rothbauer, U;Schmitt, M;Orian-Rousseau, V;
PMID: 35190527 | DOI: 10.1038/s41419-022-04607-0
Enhancement of Wnt signaling is fundamental for stem cell function during intestinal regeneration. Molecular modules control Wnt activity by regulating signal transduction. CD44 is such a positive regulator and a Wnt target gene. While highly expressed in intestinal crypts and used as a stem cell marker, its role during intestinal homeostasis and regeneration remains unknown. Here we propose a CD44 positive-feedback loop that boosts Wnt signal transduction, thus impacting intestinal regeneration. Excision of Cd44 in Cd44fl/fl;VillinCreERT2 mice reduced Wnt target gene expression in intestinal crypts and affected stem cell functionality in organoids. Although the integrity of the intestinal epithelium was conserved in mice lacking CD44, they were hypersensitive to dextran sulfate sodium, and showed more severe inflammation and delayed regeneration. We localized the molecular function of CD44 at the Wnt signalosome, and identified novel DVL/CD44 and AXIN/CD44 complexes. CD44 thus promotes optimal Wnt signaling during intestinal regeneration.
Martín-Alonso, M;Iqbal, S;Vornewald, PM;Lindholm, HT;Damen, MJ;Martínez, F;Hoel, S;Díez-Sánchez, A;Altelaar, M;Katajisto, P;Arroyo, AG;Oudhoff, MJ;
PMID: 34795242 | DOI: 10.1038/s41467-021-26904-6
Smooth muscle is an essential component of the intestine, both to maintain its structure and produce peristaltic and segmentation movements. However, very little is known about other putative roles that smooth muscle cells may have. Here, we show that smooth muscle cells may be the dominant suppliers of BMP antagonists, which are niche factors essential for intestinal stem cell maintenance. Furthermore, muscle-derived factors render epithelium reparative and fetal-like, which includes heightened YAP activity. Mechanistically, we find that the membrane-bound matrix metalloproteinase MMP17, which is exclusively expressed by smooth muscle cells, is required for intestinal epithelial repair after inflammation- or irradiation-induced injury. Furthermore, we propose that MMP17 affects intestinal epithelial reprogramming after damage indirectly by cleaving diffusible factor(s) such as the matricellular protein PERIOSTIN. Together, we identify an important signaling axis that establishes a role for smooth muscle cells as modulators of intestinal epithelial regeneration and the intestinal stem cell niche.
The circadian clock gene, Bmal1, regulates intestinal stem cell signaling and represses tumor initiation
Cellular and molecular gastroenterology and hepatology
Stokes, K;Nunes, M;Trombley, C;Flôres, DEFL;Wu, G;Taleb, Z;Alkhateeb, A;Banskota, S;Harris, C;Love, OP;Khan, WI;Rueda, L;Hogenesch, JB;Karpowicz, P;
PMID: 34534703 | DOI: 10.1016/j.jcmgh.2021.08.001
Circadian rhythms are daily physiological oscillations driven by the circadian clock: a 24-hour transcriptional timekeeper that regulates hormones, inflammation, and metabolism. Circadian rhythms are known to be important for health, but whether their loss contributes to colorectal cancer is not known.We tested the non-redundant clock gene, Bmal1, in intestinal homeostasis and tumorigenesis, using the Apcmin model of colorectal cancer.Bmal1 mutant, epithelium-conditional Bmal1 mutant, and photoperiod-disrupted mice bearing the Apcmin allele were assessed for tumorigenesis. Tumors and normal non-transformed tissue were characterized. Intestinal organoids were assessed for circadian transcription rhythms by RNA-sequencing, and in vivo and organoid assays were used to test Bmal1-dependent proliferation and self-renewal.Loss of Bmal1 or circadian photoperiod increases tumor initiation. In the intestinal epithelium the clock regulates transcripts involved in regeneration and intestinal stem cell signaling. Tumors have no self-autonomous clock function and only weak clock function in vivo. Apcmin clock-disrupted tumors exhibit high Yap (Hippo signaling) activity but exhibit low Wnt activity. Intestinal organoid assays reveal that loss of Bmal1 increases self-renewal in a Yap-dependent manner.Bmal1 regulates intestinal stem cell pathways, including Hippo signaling, and the loss of circadian rhythms potentiates tumor initiation.
Diet-induced alteration of intestinal stem cell function underlies obesity and prediabetes in mice
Aliluev, A;Tritschler, S;Sterr, M;Oppenländer, L;Hinterdobler, J;Greisle, T;Irmler, M;Beckers, J;Sun, N;Walch, A;Stemmer, K;Kindt, A;Krumsiek, J;Tschöp, MH;Luecken, MD;Theis, FJ;Lickert, H;Böttcher, A;
PMID: 34552271 | DOI: 10.1038/s42255-021-00458-9
Excess nutrient uptake and altered hormone secretion in the gut contribute to a systemic energy imbalance, which causes obesity and an increased risk of type 2 diabetes and colorectal cancer. This functional maladaptation is thought to emerge at the level of the intestinal stem cells (ISCs). However, it is not clear how an obesogenic diet affects ISC identity and fate. Here we show that an obesogenic diet induces ISC and progenitor hyperproliferation, enhances ISC differentiation and cell turnover and changes the regional identities of ISCs and enterocytes in mice. Single-cell resolution of the enteroendocrine lineage reveals an increase in progenitors and peptidergic enteroendocrine cell types and a decrease in serotonergic enteroendocrine cell types. Mechanistically, we link increased fatty acid synthesis, Ppar signaling and the Insr-Igf1r-Akt pathway to mucosal changes. This study describes molecular mechanisms of diet-induced intestinal maladaptation that promote obesity and therefore underlie the pathogenesis of the metabolic syndrome and associated complications.
Opposing effects of Wnt/β-catenin signaling on epithelial and mesenchymal cell fate in the developing cochlea
Development (Cambridge, England)
Billings, SE;Myers, NM;Quiruz, L;Cheng, AG;
PMID: 34061174 | DOI: 10.1242/dev.199091
During embryonic development, the otic epithelium and surrounding periotic mesenchymal cells originate from distinct lineages and coordinate to form the mammalian cochlea. Epithelial sensory precursors within the cochlear duct first undergo terminal mitosis before differentiating into sensory and non-sensory cells. In parallel, periotic mesenchymal cells differentiate to shape the lateral wall, modiolus and pericochlear spaces. Previously, Wnt activation was shown to promote proliferation and differentiation of both otic epithelial and mesenchymal cells. Here, we fate-mapped Wnt-responsive epithelial and mesenchymal cells in mice and found that Wnt activation resulted in opposing cell fates. In the post-mitotic cochlear epithelium, Wnt activation via β-catenin stabilization induced clusters of proliferative cells that dedifferentiated and lost epithelial characteristics. In contrast, Wnt-activated periotic mesenchyme formed ectopic pericochlear spaces and cell clusters showing a loss of mesenchymal and gain of epithelial features. Finally, clonal analyses via multi-colored fate-mapping showed that Wnt-activated epithelial cells proliferated and formed clonal colonies, whereas Wnt-activated mesenchymal cells assembled as aggregates of mitotically quiescent cells. Together, we show that Wnt activation drives transition between epithelial and mesenchymal states in a cell type-dependent manner.
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.
He, S;Lei, P;Kang, W;Cheung, P;Xu, T;Mana, M;Park, C;Wang, H;Imada, S;Russell, J;Wang, J;Wang, R;Zhou, Z;Chetal, K;Stas, E;Mohad, V;Bruun-Rasmussen, P;Sadreyev, R;Hodin, R;Zhang, Y;Breault, D;Camargo, F;Yilmaz, Ö;Fredberg, J;Saeidi, N;
| DOI: 10.1053/j.gastro.2023.02.030
Background & aims Fibrosis and tissue stiffening are hallmarks of the inflammatory bowel disease (IBD). We have hypothesized that the increased stiffness directly contributes to the dysregulation of the epithelial cell homeostasis in IBD. Here, we aim to determine the impact of tissue stiffening on the fate and function of the intestinal stem cells (ISCs). Methods We developed a long-term culture system consisting of 2.5-dimensional intestinal organoids grown on a hydrogel matrix with tunable stiffness. Single-cell RNA sequencing provided stiffness-regulated transcriptional signatures of the ISCs and their differentiated progeny. YAP-knockout and YAP-overexpression mice were used to manipulate YAP expression. In addition, we analyzed colon samples from murine colitis models and human IBD samples to assess the impact of stiffness on ISCs in vivo. Results We demonstrated that increasing the stiffness potently reduced the population of LGR5+ ISCs and KI-67+ proliferating cells. Conversely, cells expressing the stem cell marker, OLFM4, became dominant in the crypt-like compartments and pervaded the villus-like regions. Concomitantly, stiffening prompted the ISCs to preferentially differentiate toward goblet cells. Mechanistically, stiffening increased the expression of cytosolic YAP, driving the extension of OLFM4+ cells into the villus-like regions, while it induced the nuclear translocation of YAP, leading to preferential differentiation of ISCs towards goblet cells. Furthermore, analysis of colon samples from murine colitis models and IBD patients demonstrated cellular and molecular remodeling reminiscent of those observed in vitro. Conclusions Collectively, our findings highlight that matrix stiffness potently regulates the stemness of ISCs and their differentiation trajectory, supporting the hypothesis that fibrosis-induced gut stiffening plays a direct role in epithelial remodeling in IBD.
Cellular and molecular gastroenterology and hepatology
Xie, L;Fletcher, RB;Bhatia, D;Shah, D;Phipps, J;Deshmukh, S;Zhang, H;Ye, J;Lee, S;Le, L;Newman, M;Chen, H;Sura, A;Gupta, S;Sanman, LE;Yang, F;Meng, W;Baribault, H;Vanhove, GF;Yeh, WC;Li, Y;Lu, C;
PMID: 35569814 | DOI: 10.1016/j.jcmgh.2022.05.003
Current management of inflammatory bowel disease leaves a clear unmet need to treat the severe epithelial damage. Modulation of Wnt signaling might present an opportunity to achieve histological remission and mucosal healing when treating IBD. Exogenous R-spondin, which amplifies Wnt signals by maintaining cell surface expression of Frizzled (Fzd) and low-density lipoprotein receptor-related protein receptors, not only helps repair intestine epithelial damage, but also induces hyperplasia of normal epithelium. Wnt signaling may also be modulated with the recently developed Wnt mimetics, recombinant antibody-based molecules mimicking endogenous Wnts.We first compared the epithelial healing effects of RSPO2 and a Wnt mimetic with broad Fzd specificity in an acute dextran sulfate sodium mouse colitis model. Guided by Fzd expression patterns in the colon epithelium, we also examined the effects of Wnt mimetics with subfamily Fzd specificities.In the DSS model, Wnt mimetics repaired damaged colon epithelium and reduced disease activity and inflammation and had no apparent effect on uninjured tissue. We further identified that the FZD5/8 and LRP6 receptor-specific Wnt mimetic, SZN-1326-p, was associated with the robust repair effect. Through a range of approaches including single-cell transcriptome analyses, we demonstrated that SZN-1326-p directly impacted epithelial cells, driving transient expansion of stem and progenitor cells, promoting differentiation of epithelial cells, histologically restoring the damaged epithelium, and secondarily to epithelial repair, reducing inflammation.It is feasible to design Wnt mimetics such as SZN-1326-p that impact damaged intestine epithelium specifically and restore its physiological functions, an approach that holds promise for treating epithelial damage in inflammatory bowel disease.
Protein arginine methyltransferase 1 regulates cell proliferation and differentiation in adult mouse adult intestine
Xue, L;Bao, L;Roediger, J;Su, Y;Shi, B;Shi, YB;
PMID: 34158114 | DOI: 10.1186/s13578-021-00627-z
Adult stem cells play an essential role in adult organ physiology and tissue repair and regeneration. While much has been learnt about the property and function of various adult stem cells, the mechanisms of their development remain poorly understood in mammals. Earlier studies suggest that the formation of adult mouse intestinal stem cells takes place during the first few weeks after birth, the postembryonic period when plasma thyroid hormone (T3) levels are high. Furthermore, deficiency in T3 signaling leads to defects in adult mouse intestine, including reduced cell proliferation in the intestinal crypts, where stem cells reside. Our earlier studies have shown that protein arginine methyltransferase 1 (PRMT1), a T3 receptor coactivator, is highly expressed during intestinal maturation in mouse.We have analyzed the expression of PRMT1 by immunohistochemistry and studied the effect of tissue-specific knockout of PRMT1 in the intestinal epithelium.We show that PRMT1 is expressed highly in the proliferating transit amplifying cells and crypt base stem cells. By using a conditional knockout mouse line, we have demonstrated that the expression of PRMT1 in the intestinal epithelium is critical for the development of the adult mouse intestine. Specific removal of PRMT1 in the intestinal epithelium results in, surprisingly, more elongated adult intestinal crypts with increased cell proliferation. In addition, epithelial cell migration along the crypt-villus axis and cell death on the villus are also increased. Furthermore, there are increased Goblet cells and reduced Paneth cells in the crypt while the number of crypt base stem cells remains unchanged.Our finding that PRMT1 knockout increases cell proliferation is surprising considering the role of PRMT1 in T3-signaling and the importance of T3 for intestinal development, and suggests that PRMT1 likely regulates pathways in addition to T3-signaling to affect intestinal development and/or homeostasis, thus affecting cell proliferating and epithelial turn over in the adult.