Inflammatory Signals Induce AT2 Cell-Derived Damage-Associated Transient Progenitors that Mediate Alveolar Regeneration.

Tissue regeneration is a multi-step process mediated by diverse cellular hierarchies and states that are also implicated in tissue dysfunction and pathogenesis. Here we leveraged single-cell RNA sequencing in combination with in vivo lineage tracing and organoid models to finely map the trajectories of alveolar-lineage cells during injury repair and lung regeneration. We identified a distinct AT2-lineage population, damage-associated transient progenitors (DATPs), that arises during alveolar regeneration. We found that interstitial macrophage-derived IL-1β primes a subset of AT2 cells expressing Il1r1 for conversion into DATPs via a HIF1α-mediated glycolysis pathway, which is required for mature AT1 cell differentiation. Importantly, chronic inflammation mediated by IL-1β prevents AT1 differentiation, leading to aberrant accumulation of DATPs and impaired alveolar regeneration. Together, this stepwise mapping to cell fate transitions shows how an inflammatory niche controls alveolar regeneration by controlling stem cell fate and behavior.We would like to thank Emma Rawlins (University of Cambridge, UK) for valuable scientific discussions and sharing the mouse lines; We would like to thank Randall Johnson (University of Cambridge, UK) for sharing Hif1aflox/flox mouse line; Nisha Narayan and Brian Huntly for sharing materials and discussion on glycolysis experiments; Irina Pshenichnaya (Histology), Maike Paramor (NGS library), Peter Humphreys (Imaging), Andy Riddell (Flow cytometry), Simon McCallum (Flow cytometry, Cambridge NIHR BRC Cell Phenotyping Hub), Katarzyna Kania (single cell sequencing at Cancer Research UK), and Cambridge Stem Cell Institute core facilities for technical assistance; Papworth Hospital Research Tissue Bank for providing tissue samples from IPF and lung adenocarcinoma (T02233); Kelly Evans for sharing histology samples of human lung tissue samples; Seungmin Han and Woochang Hwang for discussion on the scRNA-seq analysis; Life Science Editors for editorial assistance; All Lee Lab members for helpful discussion. This work was supported by Wellcome and the Royal Society (107633/Z/15/Z) and European Research Council Starting Grant (679411). J.C. was supported by the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2017R1A6A3A03005399)

Mind Bomb 1-Expressing Intermediate Progenitors Generate Notch Signaling to Maintain Radial Glial Cells

SummaryNotch signaling is critical for the stemness of radial glial cells (RGCs) during embryonic neurogenesis. Although Notch-signal-receiving events in RGCs have been well characterized, the signal-sending mechanism by the adjacent cells is poorly understood. Here, we report that conditional inactivation of mind bomb-1 (mib1), an essential component for Notch ligand endocytosis, in mice using the nestin and hGFAP promoters resulted in complete loss of Notch activation, which leads to depletion of RGCs, and premature differentiation into intermediate progenitors (IPs) and finally neurons, which were reverted by the introduction of active Notch1. Interestingly, Mib1 expression is restricted in the migrating IPs and newborn neurons, but not in RGCs. Moreover, sorted Mib1+ IPs and neurons can send the Notch signal to neighboring cells. Our results reveal that not only newborn neurons but also IPs are essential Notch-ligand-presenting cells for maintaining RGC stemness during both symmetric and asymmetric divisions

Morphological alterations of cultured human colorectal matched tumour and healthy organoids.

Organoids have extensive applications in many fields ranging from modelling human development and disease, personalised medicine, drug screening, etc. Moreover, in the last few years, several studies have evaluated the capacity of organoids as transplantation sources for therapeutic approaches and regenerative medicine. Nevertheless, depending on the origin of the cells and anatomical complications, an organoid transplant may make tissue regeneration difficult. However, some essential aspects of organoids including the morphological alterations and the growth pattern of the matched tumour and their healthy derived organoids have received less attention. Therefore, the current work focused on culturing matched healthy and tumour organoids from the same patient with colorectal cancer (CRC) and assessed their timed growth and structural differences on a daily basis. The healthy organoids underwent proliferation and branching morphogenesis, while the tumour organoids did not follow the same pattern, and the majority of them developed cystic structures instead. However, the number and size of tumour organoids were different from one patient to another. The differential morphological changes of the healthy versus human colonic tumour organoids likely linked to distinct molecular and cellular events during each day. Thus, while their specific structural features provide valuable in vitro models to study various aspects of human intestinal/colon tissue homeostasis and CRC which avoid or replace the use of animals in research, this model may also hold a great promise for the transplantation and regenerative medicine applications

Norovirus Replication in Human Intestinal Epithelial Cells Is Restricted by the Interferon-Induced JAK/STAT Signaling Pathway and RNA Polymerase II-Mediated Transcriptional Responses.

Human noroviruses (HuNoV) are a leading cause of viral gastroenteritis worldwide and a significant cause of morbidity and mortality in all age groups. The recent finding that HuNoV can be propagated in B cells and mucosa-derived intestinal epithelial organoids (IEOs) has transformed our ability to dissect the life cycle of noroviruses. Using transcriptome sequencing (RNA-Seq) of HuNoV-infected intestinal epithelial cells (IECs), we have found that replication of HuNoV in IECs results in interferon (IFN)-induced transcriptional responses and that HuNoV replication in IECs is sensitive to IFN. This contrasts with previous studies that suggested that the innate immune response may play no role in the restriction of HuNoV replication in immortalized cells. We demonstrated that inhibition of Janus kinase 1 (JAK1)/JAK2 enhanced HuNoV replication in IECs. Surprisingly, targeted inhibition of cellular RNA polymerase II-mediated transcription was not detrimental to HuNoV replication but instead enhanced replication to a greater degree than blocking of JAK signaling directly. Furthermore, we demonstrated for the first time that IECs generated from genetically modified intestinal organoids, engineered to be deficient in the interferon response, were more permissive to HuNoV infection. Taking the results together, our work revealed that IFN-induced transcriptional responses restrict HuNoV replication in IECs and demonstrated that inhibition of these responses mediated by modifications of the culture conditions can greatly enhance the robustness of the norovirus culture system.IMPORTANCE Noroviruses are a major cause of gastroenteritis worldwide, and yet the challenges associated with their growth in culture have greatly hampered the development of therapeutic approaches and have limited our understanding of the cellular pathways that control infection. Here, we show that human intestinal epithelial cells, which represent the first point of entry of human noroviruses into the host, limit virus replication by induction of innate responses. Furthermore, we show that modulating the ability of intestinal epithelial cells to induce transcriptional responses to HuNoV infection can significantly enhance human norovirus replication in culture. Collectively, our findings provide new insights into the biological pathways that control norovirus infection but also identify mechanisms that enhance the robustness of norovirus culture

Organoide

Zusammenfassung Organoide sind dreidimensionale, aus Stammzellen entwickelte Modellsysteme für unterschiedliche Organe, die großes Potenzial für Forschung und Medizin bergen. Sie werfen wissenschaftliche, aber auch philosophische, ethische und juristische Fragen auf, die bislang in Deutschland wenig diskutiert werden. Der Themenband der interdisziplinären Arbeitsgruppe (IAG) Gentechnologiebericht an der Berlin-Brandenburgischen Akademie der Wissenschaften bietet eine Übersicht über aktuelle wissenschaftliche Entwicklungen, ihre derzeitigen und potenziellen Anwendungsmöglichkeiten sowie wissenschaftstheoretische, ethische und juristische Reflexionen. Hiermit möchte die IAG einen Anstoß zu einer interdisziplinären und gesamtgesellschaftlichen Debatte liefern. Mit Beiträgen von Cantas Alev, Aileen-Diane Bamford, Sina Bartfeld, Andreia S. Batista-Rocha, Ali H. Brivanlou, Thomas Burgold, Cindrilla Chumduri, Stephan Clemens, Emrecan Dilmen, Tobias Erb, Fred Etoc, Melinda B. Fagan, Heiner Fangerau, Boris Fehse, Nina Frey, Tristan Frum, Anne Grapin-Botton, Navin Gupta, Jürgen Hampel, Ferdinand Hucho, Özge Kayisoglu, Rashmiparvathi Keshara, Yung Hae Kim, Bon-Kyoung Koo, Martin Korte, Yaroslav Koshelev, Kai Kretzschmar, Allison Lewis, Lilian Marx-Stölting, Fruzsina Molnár-Gábor, Ryuji Morizane, Stefan Mundlos, Paola Nicolas, Angela Osterheider, In-Hyun Park, Anja Pichl, Sandra Pilat-Carotta, Jens Reich, Marlen Reinschke, Hannah Schickl, Silke Schicktanz, Nicolas Schlegel, Jason R. Spence, Yoshiaki Tanaka, Jochen Taupitz, Isaree Teriyapirom, Margherita Y. Turco, Jörn Walter, Eva Winkler, Martin Zenke. Abstract Organoids are developed from stem cells and serve as three-dimensional model systems for different organs. They have great potential for research and medicine, but also raise philosophical, ethical and legal questions which have rarely been discussed in Germany so far. This thematic study by the interdisciplinary research group (IAG) Gene Technology Report at the Berlin-Brandenburg Academy of Sciences and Humanities offers an overview of current scientific developments, their present and potential application, as well as epistemological, ethical and legal reflections. Hereby, the IAG wants to provide impetus for an interdisciplinary and society-wide debate on this general subject. With contributions by Cantas Alev, Aileen-Diane Bamford, Sina Bartfeld, Andreia S. Batista-Rocha, Ali H. Brivanlou, Thomas Burgold, Cindrilla Chumduri, Stephan Clemens, Emrecan Dilmen, Tobias Erb, Fred Etoc, Melinda B. Fagan, Heiner Fangerau, Boris Fehse, Nina Frey, Tristan Frum, Anne Grapin-Botton, Navin Gupta, Jürgen Hampel, Ferdinand Hucho, Özge Kayisoglu, Rashmiparvathi Keshara, Yung Hae Kim, Bon-Kyoung Koo, Martin Korte, Yaroslav Koshelev, Kai Kretzschmar, Allison Lewis, Lilian Marx-Stölting, Fruzsina Molnár-Gábor, Ryuji Morizane, Stefan Mundlos, Paola Nicolas, Angela Osterheider, In-Hyun Park, Anja Pichl, Sandra Pilat-Carotta, Jens Reich, Marlen Reinschke, Hannah Schickl, Silke Schicktanz, Nicolas Schlegel, Jason R. Spence, Yoshiaki Tanaka, Jochen Taupitz, Isaree Teriyapirom, Margherita Y. Turco, Jörn Walter, Eva Winkler, Martin Zenke

Mind bomb 1 in the lymphopoietic niches is essential for T and marginal zone B cell development

Notch signaling regulates lineage decisions at multiple stages of lymphocyte development, and Notch activation requires the endocytosis of Notch ligands in the signal-sending cells. Four E3 ubiquitin ligases, Mind bomb (Mib) 1, Mib2, Neuralized (Neur) 1, and Neur2, regulate the Notch ligands to activate Notch signaling, but their roles in lymphocyte development have not been defined. We show that Mib1 regulates T and marginal zone B (MZB) cell development in the lymphopoietic niches. Inactivation of the Mib1 gene, but not the other E3 ligases, Mib2, Neur1, and Neur2, abrogated T and MZB cell development. Reciprocal bone marrow (BM) transplantation experiments revealed that Mib1 in the thymic and splenic niches is essential for T and MZB cell development. Interestingly, when BM cells from transgenic Notch reporter mice were transplanted into Mib1-null mice, the Notch signaling was abolished in the double-negative thymocytes. In addition, the endocytosis of Dll1 was impaired in the Mib1-null microenvironment. Moreover, the block in T cell development and the failure of Dll1 endocytosis were also observed in coculture system by Mib1 knockdown. Our study reveals that Mib1 is the essential E3 ligase in T and MZB cell development, through the regulation of Notch ligands in the thymic and splenic microenvironments

DNA Methylation and Transcription Patterns in Intestinal Epithelial Cells From Pediatric Patients With Inflammatory Bowel Diseases Differentiate Disease Subtypes and Associate With Outcome.

BACKGROUND & AIMS: We analyzed DNA methylation patterns and transcriptomes of primary intestinal epithelial cells (IEC) of children newly diagnosed with inflammatory bowel diseases (IBD) to learn more about pathogenesis. METHODS: We obtained mucosal biopsies (N = 236) collected from terminal ileum and ascending and sigmoid colons of children (median age 13 years) newly diagnosed with IBD (43 with Crohn's disease [CD], 23 with ulcerative colitis [UC]), and 30 children without IBD (controls). Patients were recruited and managed at a hospital in the United Kingdom from 2013 through 2016. We also obtained biopsies collected at later stages from a subset of patients. IECs were purified and analyzed for genome-wide DNA methylation patterns and gene expression profiles. Adjacent microbiota were isolated from biopsies and analyzed by 16S gene sequencing. We generated intestinal organoid cultures from a subset of samples and genome-wide DNA methylation analysis was performed. RESULTS: We found gut segment-specific differences in DNA methylation and transcription profiles of IECs from children with IBD vs controls; some were independent of mucosal inflammation. Changes in gut microbiota between IBD and control groups were not as large and were difficult to assess because of large amounts of intra-individual variation. Only IECs from patients with CD had changes in DNA methylation and transcription patterns in terminal ileum epithelium, compared with controls. Colon epithelium from patients with CD and from patients with ulcerative colitis had distinct changes in DNA methylation and transcription patterns, compared with controls. In IECs from patients with IBD, changes in DNA methylation, compared with controls, were stable over time and were partially retained in ex-vivo organoid cultures. Statistical analyses of epithelial cell profiles allowed us to distinguish children with CD or UC from controls; profiles correlated with disease outcome parameters, such as the requirement for treatment with biologic agents. CONCLUSIONS: We identified specific changes in DNA methylation and transcriptome patterns in IECs from pediatric patients with IBD compared with controls. These data indicate that IECs undergo changes during IBD development and could be involved in pathogenesis. Further analyses of primary IECs from patients with IBD could improve our understanding of the large variations in disease progression and outcomes

Tracing oncogene-driven remodelling of the intestinal stem cell niche.

Interactions between tumour cells and the surrounding microenvironment contribute to tumour progression, metastasis and recurrence1-3. Although mosaic analyses in Drosophila have advanced our understanding of such interactions4,5, it has been difficult to engineer parallel approaches in vertebrates. Here we present an oncogene-associated, multicolour reporter mouse model-the Red2Onco system-that allows differential tracing of mutant and wild-type cells in the same tissue. By applying this system to the small intestine, we show that oncogene-expressing mutant crypts alter the cellular organization of neighbouring wild-type crypts, thereby driving accelerated clonal drift. Crypts that express oncogenic KRAS or PI3K secrete BMP ligands that suppress local stem cell activity, while changes in PDGFRloCD81+ stromal cells induced by crypts with oncogenic PI3K alter the WNT signalling environment. Together, these results show how oncogene-driven paracrine remodelling creates a niche environment that is detrimental to the maintenance of wild-type tissue, promoting field transformation dominated by oncogenic clones.Royal Societ

RNF43/ZNRF3 loss predisposes to hepatocellular-carcinoma by impairing liver regeneration and altering the liver lipid metabolic ground-state.

RNF43/ZNRF3 negatively regulate WNT signalling. Both genes are mutated in several types of cancers, however, their contribution to liver disease is unknown. Here we describe that hepatocyte-specific loss of Rnf43/Znrf3 results in steatohepatitis and in increase in unsaturated lipids, in the absence of dietary fat supplementation. Upon injury, Rnf43/Znrf3 deletion results in defective hepatocyte regeneration and liver cancer, caused by an imbalance between differentiation/proliferation. Using hepatocyte-, hepatoblast- and ductal cell-derived organoids we demonstrate that the differentiation defects and lipid alterations are, in part, cell-autonomous. Interestingly, ZNRF3 mutant liver cancer patients present poorer prognosis, altered hepatic lipid metabolism and steatohepatitis/NASH signatures. Our results imply that RNF43/ZNRF3 predispose to liver cancer by controlling the proliferative/differentiation and lipid metabolic state of hepatocytes. Both mechanisms combined facilitate the progression towards malignancy. Our findings might aid on the management of those RNF43/ZNRF3 mutated individuals at risk of developing fatty liver and/or liver cancer