Taieb, M;Ghannoum, D;Barré, L;Ouzzine, M;
PMID: 37296099 | DOI: 10.1038/s41419-023-05875-0
Genetic mutations in the Xylt1 gene are associated with Desbuquois dysplasia type II syndrome characterized by sever prenatal and postnatal short stature. However, the specific role of XylT-I in the growth plate is not completely understood. Here, we show that XylT-I is expressed and critical for the synthesis of proteoglycans in resting and proliferative but not in hypertrophic chondrocytes in the growth plate. We found that loss of XylT-I induces hypertrophic phenotype-like of chondrocytes associated with reduced interterritorial matrix. Mechanistically, deletion of XylT-I impairs the synthesis of long glycosaminoglycan chains leading to the formation of proteoglycans with shorter glycosaminoglycan chains. Histological and Second Harmonic Generation microscopy analysis revealed that deletion of XylT-I accelerated chondrocyte maturation and prevents chondrocytes columnar organization and arrangement in parallel of collagen fibers in the growth plate, suggesting that XylT-I controls chondrocyte maturation and matrix organization. Intriguingly, loss of XylT-I induced at embryonic stage E18.5 the migration of progenitor cells from the perichondrium next to the groove of Ranvier into the central part of epiphysis of E18.5 embryos. These cells characterized by higher expression of glycosaminoglycans exhibit circular organization then undergo hypertrophy and death creating a circular structure at the secondary ossification center location. Our study revealed an uncovered role of XylT-I in the synthesis of proteoglycans and provides evidence that the structure of glycosaminoglycan chains of proteoglycans controls chondrocyte maturation and matrix organization.
Larsen, F;Hansen, D;Terkelsen, M;Bendixen, S;Avolio, F;Wernberg, C;Lauridsen, M;Grønkjaer, L;Jacobsen, B;Klinggaard, E;Mandrup, S;Di Caterino, T;Siersbæk, M;Chandran, V;Graversen, J;Krag, A;Grøntved, L;Ravnskjaer, K;
| DOI: 10.1016/j.jhepr.2022.100615
Background & Aims Non-alcoholic fatty liver disease (NAFLD) and its progressive form, non-alcoholic steatohepatitis (NASH), are the hepatic manifestations of metabolic syndrome. Histological assessment of liver biopsies is the gold standard for diagnosis of NASH. A Liver biopsy is resource heavy, can lead to complications such as bleeding, and does not fully capture tissue heterogeneity of the fibrotic liver. Therefore, non-invasive biomarkers that can reflect an integrated state of the liver are highly needed to improve diagnosis and sampling bias. Hepatic stellate cells (HSCs) are central in development of hepatic fibrosis, a hallmark of NASH. Secreted HSC-specific proteins may, therefore, reflect disease state in the NASH liver and serve as non-invasive diagnostic biomarkers. Methods We performed RNA-sequencing on liver biopsies from a histological characterised cohort of obese patients (n = 30, body mass index > 35 kg/m2) to identify and evaluate HSC-specific genes encoding secreted proteins. Bioinformatics was used to identify potential biomarkers and their expression at single-cell resolution. We validated our findings by single-molecule fluorescence in situ hybridisation (smFISH) and ELISA to detect mRNA in liver tissue and protein levels in plasma, respectively. Results Hepatic expression of SPARC-related modular calcium-binding protein 2 (SMOC2) was increased in NASH compared no-NAFLD (p.adj < 0.001). Single-cell RNA-sequencing data indicated SMOC2 expression by HSCs, which was validated using smFISH. Finally, plasma SMOC2 was elevated in NASH compared to no-NAFLD (p < 0.001) with a predictive accuracy of AUROC 0.88. Conclusions We propose increased SMOC2 in plasma reflects HSC activation, a key cellular event associated with NASH progression, and may serve as a non-invasive biomarker of NASH.
Garcia-Alonso, L;Lorenzi, V;Mazzeo, CI;Alves-Lopes, JP;Roberts, K;Sancho-Serra, C;Engelbert, J;Marečková, M;Gruhn, WH;Botting, RA;Li, T;Crespo, B;van Dongen, S;Kiselev, VY;Prigmore, E;Herbert, M;Moffett, A;Chédotal, A;Bayraktar, OA;Surani, A;Haniffa, M;Vento-Tormo, R;
PMID: 35794482 | DOI: 10.1038/s41586-022-04918-4
Gonadal development is a complex process that involves sex determination followed by divergent maturation into either testes or ovaries1. Historically, limited tissue accessibility, a lack of reliable in vitro models and critical differences between humans and mice have hampered our knowledge of human gonadogenesis, despite its importance in gonadal conditions and infertility. Here, we generated a comprehensive map of first- and second-trimester human gonads using a combination of single-cell and spatial transcriptomics, chromatin accessibility assays and fluorescent microscopy. We extracted human-specific regulatory programmes that control the development of germline and somatic cell lineages by profiling equivalent developmental stages in mice. In both species, we define the somatic cell states present at the time of sex specification, including the bipotent early supporting population that, in males, upregulates the testis-determining factor SRY and sPAX8s, a gonadal lineage located at the gonadal-mesonephric interface. In females, we resolve the cellular and molecular events that give rise to the first and second waves of granulosa cells that compartmentalize the developing ovary to modulate germ cell differentiation. In males, we identify human SIGLEC15+ and TREM2+ fetal testicular macrophages, which signal to somatic cells outside and inside the developing testis cords, respectively. This study provides a comprehensive spatiotemporal map of human and mouse gonadal differentiation, which can guide in vitro gonadogenesis.
Ma F, Ye H, He HH, Gerrin SJ, Chen S, Tanenbaum BA, Cai C, Sowalsky AG, He L, Wang H, Balk SP, Yuan X.
PMID: 27043282 | DOI: 10.1172/JCI78815.
The transcription factor SOX9 is critical for prostate development, and dysregulation of SOX9 is implicated in prostate cancer (PCa). However, the SOX9-dependent genes and pathways involved in both normal and neoplastic prostate epithelium are largely unknown. Here, we performed SOX9 ChIP sequencing analysis and transcriptome profiling of PCa cells and determined that SOX9 positively regulates multiple WNT pathway genes, including those encoding WNT receptors (frizzled [FZD] and lipoprotein receptor-related protein [LRP] family members) and the downstream β-catenin effector TCF4. Analyses of PCa xenografts and clinical samples both revealed an association between the expression of SOX9 and WNT pathway components in PCa. Finally, treatment of SOX9-expressing PCa cells with a WNT synthesis inhibitor (LGK974) reduced WNT pathway signaling in vitro and tumor growth in murine xenograft models. Together, our data indicate that SOX9 expression drives PCa by reactivating the WNT/β-catenin signaling that mediates ductal morphogenesis in fetal prostate and define a subgroup of patients who would benefit from WNT-targeted therapy.
Thibault S, Hu W, Hirakawa B, Kalabat D, Franks T, Sung T, Khoh-Reiter S, Lu S, Finkelstein M, Jessen B, Sacaan AI.
PMID: 30401694 | DOI: 10.1158/1535-7163.MCT-18-0734
Recently three different cyclin-dependent kinase 4 and 6 (CDK4/6) dual inhibitors were approved for the treatment of breast cancer (palbociclib, ribociclib and abemaciclib), all of which offer comparable therapeutic benefits. Their safety profiles however are different. For example, neutropenia is observed at varying incidences in patients treated with these drugs; however it is the most common adverse event for palbociclib and ribociclib, whereas diarrhea is the most common adverse event observed in patients treated with abemaciclib. In order to understand the mechanism of diarrhea observed with these drugs and in an effort to guide the development of safer drugs, we compared the effects of oral administration of palbociclib, ribociclib and abemaciclib on the gastrointestinal tract of rats using doses intended to produce comparable CDK4/6 inhibition. Rats administered abemaciclib, but not palbociclib or ribociclib, had fecal alterations, unique histopathological findings and distinctive changes in intestinal gene expression. Morphologic changes in the intestine were characterized by proliferation of crypt cells, loss of goblet cells, poorly differentiated and degenerating enterocytes with loss of microvilli and mucosal inflammation. In the jejunum of abemaciclib-treated rats, down-regulation of enterocyte membrane transporters and up-regulation of genes associated with cell proliferation were observed, consistent with activation of the Wnt pathway and downstream transcriptional regulation. Among these CDK4/6 inhibitors, intestinal toxicity was unique to rats treated with abemaciclib, suggesting a mechanism of toxicity not due to primary pharmacology (CDK4/6 inhibition), but to activity at secondary pharmacological targets.
FASEB journal : official publication of the Federation of American Societies for Experimental Biology
Schaaf, CR;Polkoff, KM;Carter, A;Stewart, AS;Sheahan, B;Freund, J;Ginzel, J;Snyder, JC;Roper, J;Piedrahita, JA;Gonzalez, LM;
PMID: 37159340 | DOI: 10.1096/fj.202300223R
Intestinal epithelial stem cells (ISCs) are responsible for intestinal epithelial barrier renewal; thereby, ISCs play a critical role in intestinal pathophysiology research. While transgenic ISC reporter mice are available, advanced translational studies lack a large animal model. This study validates ISC isolation in a new porcine Leucine Rich Repeat Containing G Protein-Coupled Receptor 5 (LGR5) reporter line and demonstrates the use of these pigs as a novel colorectal cancer (CRC) model. We applied histology, immunofluorescence, fluorescence-activated cell sorting, flow cytometry, gene expression quantification, and 3D organoid cultures to whole tissue and single cells from the duodenum, jejunum, ileum, and colon of LGR5-H2B-GFP and wild-type pigs. Ileum and colon LGR5-H2B-GFP, healthy human, and murine biopsies were compared by mRNA fluorescent in situ hybridization (FISH). To model CRC, adenomatous polyposis coli (APC) mutation was induced by CRISPR/Cas9 editing in porcine LGR5-H2B-GFP colonoids. Crypt-base, green fluorescent protein (GFP) expressing cells co-localized with ISC biomarkers. LGR5-H2B-GFPhi cells had significantly higher LGR5 expression (p < .01) and enteroid forming efficiency (p < .0001) compared with LGR5-H2B-GFPmed/lo/neg cells. Using FISH, similar LGR5, OLFM4, HOPX, LYZ, and SOX9 expression was identified between human and LGR5-H2B-GFP pig crypt-base cells. LGR5-H2B-GFP/APCnull colonoids had cystic growth in WNT/R-spondin-depleted media and significantly upregulated WNT/β-catenin target gene expression (p < .05). LGR5+ ISCs are reproducibly isolated in LGR5-H2B-GFP pigs and used to model CRC in an organoid platform. The known anatomical and physiologic similarities between pig and human, and those shown by crypt-base FISH, underscore the significance of this novel LGR5-H2B-GFP pig to translational ISC research.
Ramlow, L;Falcke, M;Lindner, B;
| DOI: 10.1016/j.bpj.2022.11.1390
Stochastic spiking is a prominent feature of Ca2+ signaling. The main noise source at the cellular level are puffs from inositol-trisphosphate receptor (IP3R) channel clusters in the membrane of the endoplasmic reticulum (ER). While the random cluster activity has been known for decades, a stringent method to derive the puff noise term acting on the cytosolic Ca2+ concentration is still lacking. We adopt a popular description of neural spike generation from neuroscience, the stochastic integrate-and-fire (IF) model, to describe Ca2+ spiking. Our model consists of two components describing i) activity of IP3R clusters and ii) dynamics of the global Ca2+ concentrations in the cytosol and in the ER. Cluster activity is modeled by a Markov chain, capturing the puff. The global Ca2+ concentrations are described by a two-variable IF model driven by the puff current. For the Markov chain we derive expressions for the statistics of interpuff interval, single-puff strength, and puff current assuming constant cytosolic Ca2+, an assumption often well met because the Ca2+ concentrations vary much slower than the cluster activity does. The latter assumption also allows to approximate the driving Ca2+ dependent puff current by a white Gaussian noise. This approximation results in an IF model with nonlinear drift and multiplicative noise. We consider this reduced model in a renewal version and in a version with cumulative refractoriness. Neglecting ER depletion, the stochastic IF model has only one variable and generates a renewal spike train, a point process with statistically independent interspike intervals (ISI). We derive analytical expressions for the mean and coefficient of variation of the ISI and suggest approximations for the ISI density and spike-train power spectrum. Taking into account ER depletion, the two-variable IF model displays cumulative refractoriness as seen in experimental data.
Verdile, N;Cardinaletti, G;Faccenda, F;Brevini, T;Gandolfi, F;Tibaldi, E;
| DOI: 10.1016/j.aquaculture.2022.739031
To develop more sustainable feed formulations, it is important to assess in detail their effect on gut function and health. We previously described the specific organization of the epithelial and stromal components of the intestinal stem cell niche (ISCN), in rainbow trout (RT) under actual farming conditions. In the present work, we used our previous observation, for performing a comparative analysis between a control diet (CF) and an experimental vegetable-based diet (CV) under a new perspective. We correlated diet-induced changes of the morphology and the absorptive capability of the RT mucosa with modifications of the ISCN. Histological analysis confirmed that CV diet caused a mucosa remodeling, characterized by the generation of accessory branches sprouting from the middle of the proximal intestine folds, determining a significant increase of the luminal surface. The newly-formed structures showed positivity for PepT1, Sglt-1, and Fabp2 indicating their active role in small molecule absorption. However, the cells lining the base of the new branches expressed both epithelial (sox9) and stromal (pdgfrα and foxl1) stem cell markers, rather than the expected markers of fully differentiated cells. Our results suggest that a nutritional challenge results in the formation of an ectopic ISNC at the middle of the intestinal folds that sustains the formation of functional collateral branches, presumably to compensate for the reduced intestinal absorption. Overall, these data highlight, for the first time, the plasticity of the ISCN and its possible role in compensating intestinal functions in response to challenging conditions.
Corrêa, RO;Castro, PR;Fachi, JL;Nirello, VD;El-Sahhar, S;Imada, S;Pereira, GV;Pral, LP;Araújo, NVP;Fernandes, MF;Matheus, VA;de Souza Felipe, J;Dos Santos Pereira Gomes, AB;de Oliveira, S;de Rezende Rodovalho, V;de Oliveira, SRM;de Assis, HC;Oliveira, SC;Dos Santos Martins, F;Martens, E;Colonna, M;Varga-Weisz, P;Vinolo, MAR;
PMID: 37101209 | DOI: 10.1186/s40168-023-01520-2
The continuous proliferation of intestinal stem cells followed by their tightly regulated differentiation to epithelial cells is essential for the maintenance of the gut epithelial barrier and its functions. How these processes are tuned by diet and gut microbiome is an important, but poorly understood question. Dietary soluble fibers, such as inulin, are known for their ability to impact the gut bacterial community and gut epithelium, and their consumption has been usually associated with health improvement in mice and humans. In this study, we tested the hypothesis that inulin consumption modifies the composition of colonic bacteria and this impacts intestinal stem cells functions, thus affecting the epithelial structure.Mice were fed with a diet containing 5% of the insoluble fiber cellulose or the same diet enriched with an additional 10% of inulin. Using a combination of histochemistry, host cell transcriptomics, 16S microbiome analysis, germ-free, gnotobiotic, and genetically modified mouse models, we analyzed the impact of inulin intake on the colonic epithelium, intestinal bacteria, and the local immune compartment.We show that the consumption of inulin diet alters the colon epithelium by increasing the proliferation of intestinal stem cells, leading to deeper crypts and longer colons. This effect was dependent on the inulin-altered gut microbiota, as no modulations were observed in animals deprived of microbiota, nor in mice fed cellulose-enriched diets. We also describe the pivotal role of γδ T lymphocytes and IL-22 in this microenvironment, as the inulin diet failed to induce epithelium remodeling in mice lacking this T cell population or cytokine, highlighting their importance in the diet-microbiota-epithelium-immune system crosstalk.This study indicates that the intake of inulin affects the activity of intestinal stem cells and drives a homeostatic remodeling of the colon epithelium, an effect that requires the gut microbiota, γδ T cells, and the presence of IL-22. Our study indicates complex cross kingdom and cross cell type interactions involved in the adaptation of the colon epithelium to the luminal environment in steady state. Video Abstract.
EMBO J. 2016 Oct 17;35(20):2192-2212.
Suryo Rahmanto A, Savov V, Brunner A, Bolin S, Weishaupt H, Malyukova A, Rosén G, Čančer M, Hutter S, Sundström A, Kawauchi D, Jones DT, Spruck C, Taylor MD, Cho YJ, Pfister SM, Kool M, Korshunov A, Swartling FJ, Sangfelt O.
PMID: 27625374 | DOI: 10.15252/embj.201693889
SOX9 is a master transcription factor that regulates development and stem cell programs. However, its potential oncogenic activity and regulatory mechanisms that control SOX9 protein stability are poorly understood. Here, we show that SOX9 is a substrate of FBW7, a tumor suppressor, and a SCF (SKP1/CUL1/F-box)-type ubiquitin ligase. FBW7 recognizes a conserved degron surrounding threonine 236 (T236) in SOX9 that is phosphorylated by GSK3 kinase and consequently degraded by SCFFBW7α Failure to degrade SOX9 promotes migration, metastasis, and treatment resistance in medulloblastoma, one of the most common childhood brain tumors. FBW7 is either mutated or downregulated in medulloblastoma, and in cases where FBW7 mRNA levels are low, SOX9 protein is significantly elevated and this phenotype is associated with metastasis at diagnosis and poor patient outcome. Transcriptional profiling of medulloblastoma cells expressing a degradation-resistant SOX9 mutant reveals activation of pro-metastatic genes and genes linked to cisplatin resistance. Finally, we show that pharmacological inhibition of PI3K/AKT/mTOR pathway activity destabilizes SOX9 in a GSK3/FBW7-dependent manner, rendering medulloblastoma cells sensitive to cytostatic treatment.
Kim HS, Lee C, Kim WH, Maeng YH, Jang BG.
PMID: 28747693 | DOI: 10.1038/s41598-017-06900-x
The intestinal epithelium has two distinct two stem cell populations, namely, crypt base columnar (CBC) cells and +4 cells. Several specific markers have been identified for each stem cell population. In this study, we examined the expression profiles of these markers in colitis-associated carcinogenesis (CAC) to investigate whether they can be used as biomarkers for the early detection of dysplasia. The expression of intestinal stem cell (ISC) markers was measured by real-time polymerase chain reaction during CAC that was induced by azoxymethane and dextran sodium sulfate treatment. CBC stem cell markers increased continuously with tumor development, whereas a +4 cell expression profile was not present. CBC stem cell population was suppressed in the acute colitis and then expanded to repopulate the crypts during the regeneration period. Notably, RNA in situ hybridization revealed that all dysplasia and cancer samples showed increased expression of CBC stem cell markers in more than one-third of the tumor height, whereas regenerative glands had CBC stem cell markers confined to the lower one-third of the crypt. These results suggest that CBC stem cell markers could be a useful tool for the early detection of colitis-induced tumors.
Athwal VS, Pritchett J, Llewellyn J, Martin K, Camacho E, Raza SM, Phythian-Adams A, Birchall LJ, Mullan AF, Su K, Pearmain L, Dolman G, Zaitoun AM, Friedman SL, MacDonald A, Irving WL, Guha IN, Hanley NA, Piper Hanley K.
PMID: 29109128 | DOI: 10.15252/emmm.201707860
Fibrosis and organ failure is a common endpoint for many chronic liver diseases. Much is known about the upstream inflammatory mechanisms provoking fibrosis and downstream potential for tissue remodeling. However, less is known about the transcriptional regulation in vivo governing fibrotic matrix deposition by liver myofibroblasts. This gap in understanding has hampered molecular predictions of disease severity and clinical progression and restricted targets for antifibrotic drug development. In this study, we show the prevalence of SOX9 in biopsies from patients with chronic liver disease correlated with fibrosis severity and accurately predicted disease progression toward cirrhosis. Inactivation of Sox9 in mice protected against both parenchymal and biliary fibrosis, and improved liver function and ameliorated chronic inflammation. SOX9 was downstream of mechanosignaling factor, YAP1. These data demonstrate a role for SOX9 in liver fibrosis and open the way for the transcription factor and its dependent pathways as new diagnostic, prognostic, and therapeutic targets in patients with liver fibrosis.
