Johansson J, Naszai M, Hodder MC, Pickering KA, Miller BW, Ridgway RA, Yu Y, Peschard P, Brachmann S, Campbell AD, Cordero JB, Sansom OJ.
PMID: 30853556 | DOI: 10.1016/j.stem.2019.02.002
Ral GTPases are RAS effector molecules and by implication a potential therapeutic target for RAS mutant cancer. However, very little is known about their roles in stem cells and tissue homeostasis. Using Drosophila, we identified expression of RalA in intestinal stem cells (ISCs) and progenitor cells of the fly midgut. RalA was required within ISCs for efficient regeneration downstream of Wnt signaling. Within the murine intestine, genetic deletion of either mammalian ortholog, Rala or Ralb, reduced ISC function and Lgr5 positivity, drove hypersensitivity to Wnt inhibition, and impaired tissue regeneration following damage. Ablation of both genes resulted in rapid crypt death. Mechanistically, RALA and RALB were required for efficient internalization of the Wnt receptor Frizzled-7. Together, we identify a conserved role for RAL GTPases in the promotion of optimal Wnt signaling, which defines ISC number and regenerative potential.
Novellasdemunt L, Kucharska A, Jamieson C, Prange-Barczynska M, Baulies A, Antas P, van der Vaart J, Gehart H, Maurice MM, Li VS
PMID: 31867777 | DOI: 10.15252/embj.2019102771
The intestinal stem cell (ISC) marker LGR5 is a receptor for R-spondin (RSPO) that functions to potentiate Wnt signalling in the proliferating crypt. It has been recently shown that Wnt plays a priming role for ISC self-renewal by inducing RSPO receptor LGR5 expression. Despite its pivotal role in homeostasis, regeneration and cancer, little is known about the post-translational regulation of LGR5. Here, we show that the HECT-domain E3 ligases NEDD4 and NEDD4L are expressed in the crypt stem cell regions and regulate ISC priming by degrading LGR receptors. Loss of Nedd4 and Nedd4l enhances ISC proliferation, increases sensitivity to RSPO stimulation and accelerates tumour development in Apcmin mice with increased numbers of high-grade adenomas. Mechanistically, we find that both NEDD4 and NEDD4L negatively regulate Wnt/?-catenin signalling by targeting LGR5 receptor and DVL2 for proteasomal and lysosomal degradation. Our findings unveil the previously unreported post-translational control of LGR receptors via NEDD4/NEDD4L to regulate ISC priming. Inactivation of NEDD4 and NEDD4L increases Wnt activation and ISC numbers, which subsequently enhances tumour predisposition and progression.
Jacob, JM;Di Carlo, SE;Stzepourginski, I;Lepelletier, A;Ndiaye, PD;Varet, H;Legendre, R;Kornobis, E;Benabid, A;Nigro, G;Peduto, L;
PMID: 35523143 | DOI: 10.1016/j.stem.2022.04.005
After birth, the intestine undergoes major changes to shift from an immature proliferative state to a functional intestinal barrier. By combining inducible lineage tracing and transcriptomics in mouse models, we identify a prodifferentiation PDGFRαHigh intestinal stromal lineage originating from postnatal LTβR+ perivascular stromal progenitors. The genetic blockage of this lineage increased the intestinal stem cell pool while decreasing epithelial and immune maturation at weaning age, leading to reduced postnatal growth and dysregulated repair responses. Ablating PDGFRα in the LTBR stromal lineage demonstrates that PDGFRα has a major impact on the lineage fate and function, inducing a transcriptomic switch from prostemness genes, such as Rspo3 and Grem1, to prodifferentiation factors, including BMPs, retinoic acid, and laminins, and on spatial organization within the crypt-villus and repair responses. Our results show that the PDGFRα-induced transcriptomic switch in intestinal stromal cells is required in the first weeks after birth to coordinate postnatal intestinal maturation and function.
Klingler, S;Hsu, KS;Hua, G;Martin, ML;Adileh, M;Baslan, T;Zhang, Z;Paty, PB;Fuks, Z;Brown, AM;Kolesnick, R;
PMID: 35260534 | DOI: 10.1172/jci.insight.153793
Recent data establish a logarithmic expansion of leucine rich repeat containing G protein coupled receptor 5-positive (Lgr5+) colonic epithelial stem cells (CESCs) in human colorectal cancer (CRC). Complementary studies using the murine 2-stage azoxymethane-dextran sulfate sodium (AOM-DSS) colitis-associated tumor model indicate early acquisition of Wnt pathway mutations drives CESC expansion during adenoma progression. Here, subdivision of the AOM-DSS model into in vivo and in vitro stages revealed DSS induced physical separation of CESCs from stem cell niche cells and basal lamina, a source of Wnt signals, within hours, disabling the stem cell program. While AOM delivery in vivo under non-adenoma-forming conditions yielded phenotypically normal mucosa and organoids derived thereof, niche injury ex vivo by progressive DSS dose escalation facilitated outgrowth of Wnt-independent dysplastic organoids. These organoids contained 10-fold increased Lgr5+ CESCs with gain-of-function Wnt mutations orthologous to human CRC driver mutations. We posit CRC originates by niche injury-induced outgrowth of normally suppressed mutated stem cells, consistent with models of adaptive oncogenesis.
Wendisch, D;Dietrich, O;Mari, T;von Stillfried, S;Ibarra, I;Mittermaier, M;Mache, C;Chua, R;Knoll, R;Timm, S;Brumhard, S;Krammer, T;Zauber, H;Hiller, A;Pascual-Reguant, A;Mothes, R;Bülow, R;Schulze, J;Leipold, A;Djudjaj, S;Erhard, F;Geffers, R;Pott, F;Kazmierski, J;Radke, J;Pergantis, P;Baßler, K;Conrad, C;Aschenbrenner, A;Sawitzki, B;Landthaler, M;Wyler, E;Horst, D;Hippenstiel, S;Hocke, A;Heppner, F;Uhrig, A;Garcia, C;Machleidt, F;Herold, S;Elezkurtaj, S;Thibeault, C;Witzenrath, M;Cochain, C;Suttorp, N;Drosten, C;Goffinet, C;Kurth, F;Schultze, J;Radbruch, H;Ochs, M;Eils, R;Müller-Redetzky, H;Hauser, A;Luecken, M;Theis, F;Conrad, C;Wolff, T;Boor, P;Selbach, M;Saliba, A;Sander, L;
| DOI: 10.1016/j.cell.2021.11.033
COVID-19-induced ‘acute respiratory distress syndrome’ (ARDS) is associated with prolonged respiratory failure and high mortality, but the mechanistic basis of lung injury remains incompletely understood. Here, we analyzed pulmonary immune responses and lung pathology in two cohorts of patients with COVID-19 ARDS using functional single cell genomics, immunohistology and electron microscopy. We describe an accumulation of CD163-expressing monocyte-derived macrophages that acquired a profibrotic transcriptional phenotype during COVID-19 ARDS. Gene set enrichment and computational data integration revealed a significant similarity between COVID-19-associated macrophages and profibrotic macrophage populations identified in idiopathic pulmonary fibrosis. COVID-19 ARDS was associated with clinical, radiographic, histopathological, and ultrastructural hallmarks of pulmonary fibrosis. Exposure of human monocytes to SARS-CoV-2, but not Influenza A virus or viral RNA analogs, was sufficient to induce a similar profibrotic phenotype in vitro. In conclusion, we demonstrate that SARS-CoV-2 triggers profibrotic macrophage responses and pronounced fibroproliferative ARDS.
Fatehullah, A;Terakado, Y;Sagiraju, S;Tan, TL;Sheng, T;Tan, SH;Murakami, K;Swathi, Y;Ang, N;Rajarethinam, R;Ming, T;Tan, P;Lee, B;Barker, N;
PMID: 34857912 | DOI: 10.1038/s41556-021-00793-9
Gastric cancer is among the most prevalent and deadliest of cancers globally. To derive mechanistic insight into the pathways governing this disease, we generated a Claudin18-IRES-CreERT2 allele to selectively drive conditional dysregulation of the Wnt, Receptor Tyrosine Kinase and Trp53 pathways within the gastric epithelium. This resulted in highly reproducible metastatic, chromosomal-instable-type gastric cancer. In parallel, we developed orthotopic cancer organoid transplantation models to evaluate tumour-resident Lgr5+ populations as functional cancer stem cells via in vivo ablation. We show that Cldn18 tumours accurately recapitulate advanced human gastric cancer in terms of disease morphology, aberrant gene expression, molecular markers and sites of distant metastases. Importantly, we establish that tumour-resident Lgr5+ stem-like cells are critical to the initiation and maintenance of tumour burden and are obligatory for the establishment of metastases. These models will be invaluable for deriving clinically relevant mechanistic insights into cancer progression and as preclinical models for evaluating therapeutic targets.
NOTUM from Apc-mutant cells biases clonal competition to initiate cancer
Flanagan, DJ;Pentinmikko, N;Luopajärvi, K;Willis, NJ;Gilroy, K;Raven, AP;Mcgarry, L;Englund, JI;Webb, AT;Scharaw, S;Nasreddin, N;Hodder, MC;Ridgway, RA;Minnee, E;Sphyris, N;Gilchrist, E;Najumudeen, AK;Romagnolo, B;Perret, C;Williams, AC;Clevers, H;Nummela, P;Lähde, M;Alitalo, K;Hietakangas, V;Hedley, A;Clark, W;Nixon, C;Kirschner, K;Jones, EY;Ristimäki, A;Leedham, SJ;Fish, PV;Vincent, JP;Katajisto, P;Sansom, OJ;
PMID: 34079124 | DOI: 10.1038/s41586-021-03525-z
The tumour suppressor APC is the most commonly mutated gene in colorectal cancer. Loss of Apc in intestinal stem cells drives the formation of adenomas in mice via increased WNT signalling1, but reduced secretion of WNT ligands increases the ability of Apc-mutant intestinal stem cells to colonize a crypt (known as fixation)2. Here we investigated how Apc-mutant cells gain a clonal advantage over wild-type counterparts to achieve fixation. We found that Apc-mutant cells are enriched for transcripts that encode several secreted WNT antagonists, with Notum being the most highly expressed. Conditioned medium from Apc-mutant cells suppressed the growth of wild-type organoids in a NOTUM-dependent manner. Furthermore, NOTUM-secreting Apc-mutant clones actively inhibited the proliferation of surrounding wild-type crypt cells and drove their differentiation, thereby outcompeting crypt cells from the niche. Genetic or pharmacological inhibition of NOTUM abrogated the ability of Apc-mutant cells to expand and form intestinal adenomas. We identify NOTUM as a key mediator during the early stages of mutation fixation that can be targeted to restore wild-type cell competitiveness and provide preventative strategies for people at a high risk of developing colorectal cancer.
Peripheral and lung resident memory T cell responses against SARS-CoV-2
Grau-Expósito, J;Sánchez-Gaona, N;Massana, N;Suppi, M;Astorga-Gamaza, A;Perea, D;Rosado, J;Falcó, A;Kirkegaard, C;Torrella, A;Planas, B;Navarro, J;Suanzes, P;Álvarez-Sierra, D;Ayora, A;Sansano, I;Esperalba, J;Andrés, C;Antón, A;Ramón Y Cajal, S;Almirante, B;Pujol-Borrell, R;Falcó, V;Burgos, J;Buzón, MJ;Genescà, M;
PMID: 34021148 | DOI: 10.1038/s41467-021-23333-3
Resident memory T cells (TRM) positioned within the respiratory tract are probably required to limit SARS-CoV-2 spread and COVID-19. Importantly, TRM are mostly non-recirculating, which reduces the window of opportunity to examine these cells in the blood as they move to the lung parenchyma. Here, we identify circulating virus-specific T cell responses during acute infection with functional, migratory and apoptotic patterns modulated by viral proteins and associated with clinical outcome. Disease severity is associated predominantly with IFNγ and IL-4 responses, increased responses against S peptides and apoptosis, whereas non-hospitalized patients have increased IL-12p70 levels, degranulation in response to N peptides and SARS-CoV-2-specific CCR7+ T cells secreting IL-10. In convalescent patients, lung-TRM are frequently detected even 10 months after initial infection, in which contemporaneous blood does not reflect tissue-resident profiles. Our study highlights a balanced anti-inflammatory antiviral response associated with a better outcome and persisting TRM cells as important for future protection against SARS-CoV-2 infection.
Human kidney is a target for novel severe acute respiratory syndrome coronavirus 2 infection
Diao, B;Wang, C;Wang, R;Feng, Z;Zhang, J;Yang, H;Tan, Y;Wang, H;Wang, C;Liu, L;Liu, Y;Liu, Y;Wang, G;Yuan, Z;Hou, X;Ren, L;Wu, Y;Chen, Y;
PMID: 33947851 | DOI: 10.1038/s41467-021-22781-1
It is unclear whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can directly infect human kidney, thus leading to acute kidney injury (AKI). Here, we perform a retrospective analysis of clinical parameters from 85 patients with laboratory-confirmed coronavirus disease 2019 (COVID-19); moreover, kidney histopathology from six additional COVID-19 patients with post-mortem examinations was performed. We find that 27% (23/85) of patients exhibited AKI. The elderly patients and cases with comorbidities (hypertension and heart failure) are more prone to develop AKI. Haematoxylin & eosin staining shows that the kidneys from COVID-19 autopsies have moderate to severe tubular damage. In situ hybridization assays illustrate that viral RNA accumulates in tubules. Immunohistochemistry shows nucleocapsid and spike protein deposits in the tubules, and immunofluorescence double staining shows that both antigens are restricted to the angiotensin converting enzyme-II-positive tubules. SARS-CoV-2 infection triggers the expression of hypoxic damage-associated molecules, including DP2 and prostaglandin D synthase in infected tubules. Moreover, it enhances CD68+ macrophages infiltration into the tubulointerstitium, and complement C5b-9 deposition on tubules is also observed. These results suggest that SARS-CoV-2 directly infects human kidney to mediate tubular pathogenesis and AKI.
Immunohistochemical Study of a Correlation between Pemphigus Vulgaris Activity Score and Stem Cell Control
The Egyptian Journal of Hospital Medicine
Bazid, H;Seleit, I;Abo Hegazy, S;Samaka, R;
| DOI: 10.21608/ejhm.2021.165168
BACKGROUND: Pemphigus vulgaris (PV) is a potentially life-threatening autoimmune blistering disease. PV autoantibodies disrupt desmosomal adhesion and cause acantholysis. Previous researches have shown that stem cells are indirectly involved as a result of desmoglein deficiency. Leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5) as a follicular stem cell marker was evaluated in aim to correlate its intensity of expression with disease severity. OBJECTIVE: To correlate LGR5 intensity of expression with disease severity. PATIENT AND METHODS: This prospective cross sectional study was carried out on 20 PV patients. Patients were subjected to complete history taking, general, dermatological examination and assessment of disease severity by the Pemphigus Vulgaris Activity Score (PVAS), histopathological and immunohistochemical expression of LGR5 were done. RESULTS: All studied cases showed positive cytoplasmic basal LGR5 expression in patchy manner. 75% of cases had mild intensity of expression, 15% had moderate intensity and their Histo (H) score ranged from 50-130 with Mean ±SD 110±18.92. There were no significant correlation between PVAS scores ''skin, mucosa and total involvement'' and H score of LGR5 expression. CONCLUSION: The current study could shed a new light on the disease and its correlation with stem cells, LGR5 as a stem cell marker could be related to the healing process in PV. However, it didn't correlate PVAS scores either in skin, mucosa or total involvement.
Neurotensin regulates proliferation and stem cell function in the small intestine in a nutrient-dependent manner
Cellular and molecular gastroenterology and hepatology
Rock, SA;Jiang, K;Wu, Y;Liu, Y;Li, J;Weiss, HL;Wang, C;Jia, J;Gao, T;Evers, BM;
PMID: 34560309 | DOI: 10.1016/j.jcmgh.2021.09.006
Intestinal stem cells (ISCs) are sensitive to dietary alterations and nutrient availability. Neurotensin (NT), a gut peptide localized predominantly to the small bowel and released by fat ingestion, stimulates the growth of intestinal mucosa under basal conditions and during periods of nutrient deprivation, suggesting a possible role for NT on ISC function.Lgr5-EGFP, NT wild type (Nt+/+) and Lgr5-EGFP, NT knockout (Nt-/-) mice were fed ad libitum (AL) or fasted for 48 h. Small intestine tissue and crypts were examined by gene expression analyses, fluorescence-activated cell sorting, western blot, immunohistochemistry, and crypt-derived organoid culture. Drosophila expressing NT in midgut enteroendocrine cells were fed a standard diet or low-energy diet and esg-GFP+ ISCs quantified via immunofluorescence.Loss of NT impaired crypt cell proliferation and ISC function in a manner dependent on nutrient status. Under nutrient-rich conditions, NT stimulated ERK1/2 signaling and the expression of genes that promote cell cycle progression, leading to crypt cell proliferation. Under conditions of nutrient depletion, NT stimulated WNT/ -catenin signaling and promoted an ISC gene signature, leading to enhanced ISC function. NT was required for the induction of WNT/ -catenin signaling and ISC-specific gene expression during nutrient depletion, and loss of NT reduced crypt cell proliferation and impaired ISC function and Lgr5 expression in the intestine during fasting. Conversely, the expression of NT in midgut enteroendocrine cells of Drosophila prevented loss of ISCs during nutrient depletion.Collectively, our findings establish an evolutionarily conserved role for NT in ISC maintenance during nutritional stress.
Induction of gastric cancer by successive oncogenic activation in the corpus
Douchi, D;Yamamura, A;Matsuo, J;Melissa Lim, YH;Nuttonmanit, N;Shimura, M;Suda, K;Chen, S;ShuChin, P;Kohu, K;Abe, T;Shioi, G;Kim, G;Shabbir, A;Srivastava, S;Unno, M;Bok-Yan So, J;Teh, M;Yeoh, KG;Huey Chuang, LS;Ito, Y;
PMID: 34391772 | DOI: 10.1053/j.gastro.2021.08.013
Metaplasia and dysplasia in the corpus are reportedly derived from dedifferentiation of chief cells. However, the cellular origin of metaplasia and cancer remained uncertain. Therefore, we investigated whether pepsinogen C-transcript expressing cells (PGC-transcript expressing cells) represent the cellular origin of metaplasia and cancer using a novel Pgc-specific CreERT2 recombinase mouse model.We generated a Pgc-mCherry-IRES-CreERT2 (Pgc-CreERT2) knock-in mouse model. Pgc-CreERT2/+ and Rosa-EYFP mice were crossed to generate Pgc-CreERT2/Rosa-EYFP (Pgc-CreERT2/YFP) mice. Gastric tissues were collected, followed by lineage-tracing experiments, histological and immunofluorescence staining. We further established Pgc-CreERT2;KrasG12D/+ mice and investigated whether PGC-transcript expressing cells are responsible for the precancerous state in gastric glands. To investigate cancer development from PGC-transcript expressing cells with activated Kras, inactivated Apc and Trp53 signaling pathways, we crossed Pgc-CreERT2/+ mice with conditional KrasG12D, Apcflox, Trp53flox mice.Expectedly, mCherry mainly labeled chief cells in the Pgc-CreERT2 mice. However, mCherry was also detected throughout the neck cell and isthmal stem/progenitor regions, albeit at lower levels. In the Pgc-CreERT2;KrasG12D/+ mice, PGC-transcript expressing cells with KrasG12D/+ mutation presented pseudopyloric metaplasia. The early induction of proliferation at the isthmus may reflect the ability of isthmal progenitors to react rapidly to Pgc-driven KrasG12D/+ oncogenic mutation. Furthermore, Pgc-CreERT2;KrasG12D/+;Apcflox/flox mice presented intramucosal dysplasia/carcinoma, while Pgc-CreERT2;KrasG12D/+;Apcflox/flox;Trp53flox/flox mice presented invasive and metastatic gastric carcinoma.The Pgc-CreERT2 knock-in mouse is an invaluable tool to study the effects of successive oncogenic activation in the mouse corpus. Time-course observations can be made regarding the responses of isthmal and chief cells to oncogenic insults. We can observe stomach-specific tumorigenesis from the beginning to metastatic development.
