基于小分子筛选的嗅上皮类器官培养体系的建立

嗅上皮接收和传导气味信号是嗅觉系统的重要组成部分。嗅上皮的损伤在通常情况下可自发恢复,但特定疾病或衰老造成的嗅上皮损伤会引起嗅觉功能减退和嗅觉障碍。嗅上皮主要由基底细胞、支持细胞以及嗅感觉神经元组成。为了在体外建立包含多种细胞类型的嗅上皮类器官,本研究采用3D细胞培养技术,通过筛选小分子药物,构建了包含多种细胞类型的嗅上皮类器官模型,包含水平基底样细胞、球形基底样细胞、支持样细胞和嗅感觉神经元样细胞多种细胞类型。类器官培养体系中多种生长因子和小分子化合物在细胞增殖速度、细胞组成以及不同细胞类型标志基因的表达水平等方面对类器官产生影响。Wnt信号通路激活剂CHIR-99021能够提高嗅上皮类器官的成克隆率和增殖速度且有利于提高嗅上皮类器官中嗅感觉神经元样细胞标志基因的表达水平;培养体系的任一因子均能提高类器官中cKit阳性的球形基底样细胞克隆比例;表皮生长因子(epidermal growth factor,EGF)和维生素C均有利于类器官中水平基底样细胞标志基因的表达。本研究建立的嗅上皮类器官系统模拟了嗅上皮干细胞分化产生多种嗅上皮细胞类型的过程,为研究嗅上皮组织损伤再生、嗅觉障碍病理...     

Establishment of intestinal organoid cultures modeling injury-associated epithelial regeneration

The capacity of 3D organoids to mimic physiological tissue organization and functionality has provided an invaluable tool to model development and disease in vitro. However, conventional organoid cultures primarily represent the homeostasis of self-organizing stem cells and their derivatives. Here, we established a novel intestinal organoid culture system composed of 8 components, mainly including VPA, EPZ6438, LDN193189, and R-Spondin 1 conditioned medium, which mimics the gut epithelium regeneration that produces hyperplastic crypts following injury; therefore, these organoids were designated hyperplastic intestinal organoids (Hyper-organoids). Single-cell RNA sequencing identified different regenerative stem cell populations in our Hyper-organoids that shared molecular features with in vivo injury-responsive Lgr5⁺ stem cells or Clu⁺ revival stem cells. Further analysis revealed that VPA and EPZ6438 were indispensable for epigenome reprogramming and regeneration in Hyper-organoids, which functioned through epigenetically regulating YAP signaling. Furthermore, VPA and EPZ6438 synergistically promoted regenerative response in gut upon damage in vivo. In summary, our results demonstrated a new in vitro organoid model to study epithelial regeneration, highlighting the importance of epigenetic reprogramming that pioneers tissue repair.Subject terms: Intestinal stem cells, Regeneration     

Screening drug effects in patient‐derived cancer cells links organoid responses to genome alterations

Cancer drug screening in patient‐derived cells holds great promise for personalized oncology and drug discovery but lacks standardization. Whether cells are cultured as conventional monolayer or advanced, matrix‐dependent organoid cultures influences drug effects and thereby drug selection and clinical success. To precisely compare drug profiles in differently cultured primary cells, we developed DeathPro, an automated microscopy‐based assay to resolve drug‐induced cell death and proliferation inhibition. Using DeathPro, we screened cells from ovarian cancer patients in monolayer or organoid culture with clinically relevant drugs. Drug‐induced growth arrest and efficacy of cytostatic drugs differed between the two culture systems. Interestingly, drug effects in organoids were more diverse and had lower therapeutic potential. Genomic analysis revealed novel links between drug sensitivity and DNA repair deficiency in organoids that were undetectable in monolayers. Thus, our results highlight the dependency of cytostatic drugs and pharmacogenomic associations on culture systems, and guide culture selection for drug tests.     

R‐spondin 1 and noggin facilitate expansion of resident stem cells from non‐damaged gallbladders

Pioneering studies within the last few years have allowed the in vitro expansion of tissue‐specific adult stem cells from a variety of endoderm‐derived organs, including the stomach, small intestine, and colon. Expansion of these cells requires activation of the receptor Lgr5 by its ligand R‐spondin 1 and is likely facilitated by the fact that in healthy adults the stem cells in these organs are highly proliferative. In many other adult organs, such as the liver, proliferating cells are normally not abundant in adulthood. However, upon injury, the liver has a strong regenerative potential that is accompanied by the emergence of Lgr5‐positive stem cells; these cells can be isolated and expanded in vitro as organoids. In an effort to isolate stem cells from non‐regenerating mouse livers, we discovered that healthy gallbladders are a rich source of stem/progenitor cells that can be propagated in culture as organoids for more than a year. Growth of these organoids was stimulated by R‐spondin 1 and noggin, whereas in the absence of these growth factors, the organoids differentiated partially toward the hepatocyte fate. When transplanted under the liver capsule, gallbladder‐derived organoids maintained their architecture for 2 weeks. Furthermore, single cells prepared from dissociated organoids and injected into the mesenteric vein populated the liver parenchyma of carbon tetrachloride‐treated mice. Human gallbladders were also a source of organoid‐forming stem cells. Thus, under specific growth conditions, stem cells can be isolated from healthy gallbladders, expanded almost indefinitely in vitro, and induced to differentiate toward the hepatocyte lineage.     

A Protocol for Lentiviral Transduction and Downstream Analysis of Intestinal Organoids

Intestinal crypt-villus structures termed organoids, can be kept in sustained culture three dimensionally when supplemented with the appropriate growth factors. Since organoids are highly similar to the original tissue in terms of homeostatic stem cell differentiation, cell polarity and presence of all terminally differentiated cell types known to the adult intestinal epithelium, they serve as an essential resource in experimental research on the epithelium. The possibility to express transgenes or interfering RNA using lentiviral or retroviral vectors in organoids has increased opportunities for functional analysis of the intestinal epithelium and intestinal stem cells, surpassing traditional mouse transgenics in speed and cost. In the current video protocol we show how to utilize transduction of small intestinal organoids with lentiviral vectors illustrated by use of doxycylin inducible transgenes, or IPTG inducible short hairpin RNA for overexpression or gene knockdown. Furthermore, considering organoid culture yields minute cell counts that may even be reduced by experimental treatment, we explain how to process organoids for downstream analysis aimed at quantitative RT-PCR, RNA-microarray and immunohistochemistry. Techniques that enable transgene expression and gene knock down in intestinal organoids contribute to the research potential that these intestinal epithelial structures hold, establishing organoid culture as a new standard in cell culture.     

Murine intestinal organoids resemble intestinal epithelium in their microRNA profiles

Intestinal organoids were established as an ex vivo model of the intestinal epithelium. We investigated whether organoids resemble the intestinal epithelium in their microRNA (miRNA) profiles. Total RNA samples were obtained from crypt and villus fractions in murine intestine and from cultured organoids. Microarray analysis showed that organoids largely resembled intestinal epithelial cells in their miRNA profiles. In silico prediction followed by qRT-PCR suggested that six genes are regulated by corresponding miRNAs along the crypt-villus axis, suggesting miRNA regulation of epithelial cell renewal in the intestine. However, such expression patterns of miRNAs and their target mRNAs were not reproduced during organoids maturation. This might be due to lack of luminal factors and endocrine, nervous, and immune systems in organoids and different cell populations between in vivo epithelium and organoids. Nevertheless, we propose that intestinal organoids provide a useful in vitro model to investigate miRNA expression in intestinal epithelial cells.     

A three-dimensional tissue culture model for the study of attach and efface lesion formation by enteropathogenic and enterohaemorrhagic Escherichia coli

We sought to develop a practical and representative model to study the interactions of enteropathogenic and enterohaemorrhagic Escherichia coli (EPEC and EHEC, respectively) with human intestinal tissue. For this purpose, human intestinal epithelial HCT-8 cells were cultured under low-shear microgravity conditions in a rotating cell culture system. After 10 days, layered cell aggregates, or 'organoids', developed. Three lines of evidence indicated that these organoids exhibited traits characteristic of normal tissue. First, the organoids expressed normal intestinal tissue markers in patterns that suggested greater cellular differentiation in the organoids than conventionally grown monolayers. Second, the organoids produced higher levels of intestinally expressed disaccharidases and alkaline phosphatase on a cell basis than did conventionally cultured monolayers. Third, HCT-8 organoid tissue developed microvilli and desmosomes characteristic of normal tissue, as revealed by electron microscopy. Because the low-shear microgravity condition is proposed by modelling studies to more closely approximate conditions in the intestinal microvilli, we also tested the impact of microgravity of bacterial growth and virulence gene expression. No influence on growth rates was observed but intimin expression by EHEC was elevated during culture in microgravity as compared with normal gravity. That the responses of HCT-8 organoids to infection with wild-type EPEC or EHEC under microgravitational conditions approximated infection of normal tissue was demonstrated by the classical appearance of the resultant attaching and effacing lesions. We concluded that the low shear microgravity environment promoted growth of intestinal cell organoids with greater differentiation than was seen in HCT-8 cells maintained in conventional tissue culture and provided a reduced gravity environment for study of bacterial-host cell interactions.     

In vitro Organoid Culture of Primary Mouse Colon Tumors

Several human and murine colon cancer cell lines have been established, physiologic integrity of colon tumors such as multiple cell layers, basal-apical polarity, ability to differentiate, and anoikis are not maintained in colon cancer derived cell lines. The present study demonstrates a method for culturing primary mouse colon tumor organoids adapted from Sato T et al. ¹, which retains important physiologic features of colon tumors. This method consists of mouse colon tumor tissue collection, adjacent normal colon epithelium dissociation, colon tumor cells digestion into single cells, embedding colon tumor cells into matrigel, and selective culture based on the principle that tumor cells maintain growth on limiting nutrient conditions compared to normal epithelial cells.The primary tumor organoids if isolated from genetically modified mice provide a very useful system to assess tumor autonomous function of specific genes. Moreover, the tumor organoids are amenable to genetic manipulation by virus meditated gene delivery; therefore signaling pathways involved in the colon tumorigenesis could also be extensively investigated by overexpression or knockdown. Primary tumor organoids culture provides a physiologic relevant and feasible means to study the mechanisms and therapeutic modalities for colon tumorigenesis.     

Derivation of the clonal‐cell lines from Siberian sturgeon (Acipenser baerii) head‐kidney cell lines and its applicability to foreign gene expression and virus culture

This study was conducted to establish and characterize the clonal‐cell lines from Siberian sturgeon Acipenser baerii head‐kidney tissues and to evaluate its applicability as a research tool. From the culture of A. baerii head‐kidney derived cells, 10 cell lines were established first and then eight clonal‐cell lines were derived from clonal growth and colony expansion of two cell lines that showed significant high colony‐forming ability. All eight clonal‐cell lines were morphologically similar and grew stably under monolayer culture but their growth rates were significantly different. They possessed diploid DNA contents, expressed epithelial cell‐related genes and showed strong anchorage dependency to substrates. When a clonal‐cell line was transfected separately with three plasmid vectors including fluorescent reporter genes driven by cytomegalovirus, marine medaka Oryzias dancena β‐actin or A. baerii β‐actin promoter, the cell lines expressed fluorescent signals regardless of promoter types. The cells harbouring foreign genes could be expanded to stable cell lines under drug selection and then they additionally could form the extensively proliferating colonies at low‐density culture. Finally, the clonal‐cell lines showed the susceptibility to viral haemorrhagic septicaemia virus (VHSV). Collectively, the clonal‐cell lines from A. baerii head kidney were established and these cell lines will be able to provide an excellent in vitro system for various biological studies in this fish species.     

A comparison of primary oesophageal squamous epithelial cells with HET‐1A in organotypic culture

Background Information. Carcinoma of the oesophagus is the sixth leading cause of cancer death in the western world and is associated with a 5‐year survival of less than 15%. Recent evidence suggests that stromal—epithelial interactions are fundamental in carcinogenesis. The advent of co‐culture techniques permits the investigation of cross‐talk between the stroma and epithelium in a physiological setting. We have characterized a histologically representative oesophageal organotypic model and have used it to compare the most commonly used squamous oesophageal cell line, HET‐1A, with primary oesophageal squamous cells for use in studies of the oesophageal epithelium in vitro. Results. When grown in an organotypic culture with normal fibroblasts, the oesophageal carcinoma cell lines OE21 (squamous) and OE19 (adenocarcinoma) morphologically resembled the tumour of origin with evidence of stromal invasion and mucus production, respectively. However, HET‐1A cells, which were derived from normal squamous oesophageal cells, appeared dysplastic and failed to display evidence of squamous differentiation. By comparison with primary oesophageal epithelial cells, the HET‐1A cells were highly proliferative and did not express the epithelial markers E‐cadherin or CK5/6 (casein kinase 5/6), or the stratified epithelial marker ΔNp63, but did express the mesenchymal markers vimentin and N‐cadherin. Conclusion. Studies of epithelial carcinogenesis will benefit from culture systems which allow manipulation of the stromal and epithelial layers independently. We have developed an organotypic culture using primary oesophageal squamous cells and fibroblasts in which a stratified epithelium with a proliferative basal layer that stains strongly for ΔNp63 develops. This model will be suitable for the study of the molecular events in the development of Barrett's oesophagus. The most commonly used normal oesophageal squamous cell line, HET‐1A, does not have the characteristics of normal oesophageal squamous cells and should not be used in models of the normal oesophageal epithelium. Until more representative cell lines are available, future studies in oesophageal cancer will be reliant on the availability and manipulation of primary tissue.     

Host‐microbe interaction in the gastrointestinal tract

The gastrointestinal tract is a highly complex organ in which multiple dynamic physiological processes are tightly coordinated while interacting with a dense and extremely diverse microbial population. From establishment in early life, through to host‐microbe symbiosis in adulthood, the gut microbiota plays a vital role in our development and health. The effect of the microbiota on gut development and physiology is highlighted by anatomical and functional changes in germ‐free mice, affecting the gut epithelium, immune system and enteric nervous system. Microbial colonisation promotes competent innate and acquired mucosal immune systems, epithelial renewal, barrier integrity, and mucosal vascularisation and innervation. Interacting or shared signalling pathways across different physiological systems of the gut could explain how all these changes are coordinated during postnatal colonisation, or after the introduction of microbiota into germ‐free models. The application of cell‐based in‐vitro experimental systems and mathematical modelling can shed light on the molecular and signalling pathways which regulate the development and maintenance of homeostasis in the gut and beyond.     

小鼠肠道类器官三种不同条件培养基的比较研究

摘要 目的：比较三种不同条件培养基对小鼠类器官形态和增殖速度的影响。方法：取C57BL/6小鼠的小肠和结肠,EDTA法分离隐窝,以基质胶包埋,加入不同小鼠肠道类器官培养基培养7 天,使用光学显微镜记录和比较类器官形成率和出芽情况。随后进行二代类器官培养,使用TrypLE将类器官消化为单细胞,重新包埋和培养,使用光学显微镜记录和比较不同类器官培养基对二代类器官的培养效率。采用荧光定量PCR比较不同条件培养类器官中干细胞标志物Lgr5和分化标志物MUC2的表达。使用免疫荧光法检测类器官中ki-67的表达。结果：对于小肠类器官的培养,使用条件培养基1、IntestiCult条件培养基和L-WRN培养基培养结肠类器官的形成率分别为（18.2±4.5） %、（63.8±4.0） %和（82.1±8.4） %。其中使用IntestiCult条件培养基培养类器官的出芽率更高。对于结肠类器官的培养,使用条件培养基1、IntestiCult条件培养基和L-WRN培养基培养结肠类器官的形成率分别为（17.3±7.3） %、（58.0±6.1） %和（46.3±7.4） %。对于二代类器官的培养,IntestiCult条件培养基和L-WRN培养基都能够支持消化为单细胞后的二代类器官培养。干细胞标志物Lgr5和分化细胞（杯状细胞）标志物MUC2的表达无明显差异。使用L-WRN培养基的类器官ki-67阳性比例更高,增殖速度更快。结论：本研究比较了三种不同条件培养基对小鼠类器官形态和增殖速度的影响。经过对比,L-WRN培养基更有利于小鼠肠道类器官的形成和增殖速度。     

Establishment of Human Epithelial Enteroids and Colonoids from Whole Tissue and Biopsy

The epithelium of the gastrointestinal tract is constantly renewed as it turns over. This process is triggered by the proliferation of intestinal stem cells (ISCs) and progeny that progressively migrate and differentiate toward the tip of the villi. These processes, essential for gastrointestinal homeostasis, have been extensively studied using multiple approaches. Ex vivo technologies, especially primary cell cultures have proven to be promising for understanding intestinal epithelial functions. A long-term primary culture system for mouse intestinal crypts has been established to generate 3-dimensional epithelial organoids. These epithelial structures contain crypt- and villus-like domains reminiscent of normal gut epithelium. Commonly, termed “enteroids” when derived from small intestine and “colonoids” when derived from colon, they are different from organoids that also contain mesenchyme tissue. Additionally, these enteroids/colonoids continuously produce all cell types found normally within the intestinal epithelium. This in vitro organ-like culture system is rapidly becoming the new gold standard for investigation of intestinal stem cell biology and epithelial cell physiology. This technology has been recently transferred to the study of human gut. The establishment of human derived epithelial enteroids and colonoids from small intestine and colon has been possible through the utilization of specific culture media that allow their growth and maintenance over time. Here, we describe a method to establish a small intestinal and colon crypt-derived system from human whole tissue or biopsies. We emphasize the culture modalities that are essential for the successful growth and maintenance of human enteroids and colonoids.     

High‐fat diet‐induced dysbiosis mediates MCP‐1/CCR2 axis‐dependent M2 macrophage polarization and promotes intestinal adenoma‐adenocarcinoma sequence

High‐fat diet (HFD) is a well‐known risk factor for gut microbiota dysbiosis and colorectal cancer (CRC). However, evidence relating HFD, gut microbiota and carcinogenesis is limited. Our study aimed to demonstrate that HFD‐induced gut dysbiosis promoted intestinal adenoma‐adenocarcinoma sequence. In clinical study, we found that HFD increased the incidence of advanced colorectal neoplasia (AN). The expression of monocyte chemoattractant protein 1 (MCP‐1), CC chemokine receptor 2 (CCR2) and CD163 in CRC patients with HFD was significantly higher than that in CRC patients with normal diet. When it comes to the Apc^min/+ mice, HFD consumption could induce gut dysbiosis and promote intestinal carcinogenesis, accompanying with activation of MCP‐1/CCR2 axis that recruited and polarized M2 tumour‐associated macrophages. Interestingly, transfer of faecal microbiota from HFD‐fed mice to another batch of Apc^min/+ mice in the absence of HFD could also enhance carcinogenesis without significant body weight gain and induced MCP‐1/CCR2 axis activation. HFD‐induced dysbiosis could also be transmitted. Meanwhile, antibiotics cocktail treatment was sufficient to inhibit HFD‐induced carcinogenesis, indicating the vital role of dysbiosis in cancer development. Conclusively, these data indicated that HFD‐induced dysbiosis accelerated intestinal adenoma‐adenocarcinoma sequence through activation of MCP‐1/CCR2 axis, which would provide new insight into better understanding of the mechanisms and prevention for HFD‐related CRC.     

The science and engineering of stem cell-derived organoids-examples from hepatic,biliary, and pancreatic tissues

The field of organoid engineering promises to revolutionize medicine with wide-ranging applications of scientific, engineering, and clinical interest, including precision and personalized medicine, gene editing, drug development, disease modelling, cellular therapy, and human development. Organoids are a three-dimensional (3D) miniature representation of a target organ, are initiated with stem/progenitor cells, and are extremely promising tools with which to model organ function. The biological basis for organoids is that they foster stem cell self-renewal, differentiation, and self-organization, recapitulating 3D tissue structure or function better than two-dimensional (2D) systems. In this review, we first discuss the importance of epithelial organs and the general properties of epithelial cells to provide a context and rationale for organoids of the liver, pancreas, and gall bladder. Next, we develop a general framework to understand self-organization, tissue hierarchy, and organoid cultivation. For each of these areas, we provide a historical context, and review a wide range of both biological and mathematical perspectives that enhance understanding of organoids. Next, we review existing techniques and progress in hepatobiliary and pancreatic organoid engineering. To do this, we review organoids from primary tissues, cell lines, and stem cells, and introduce engineering studies when applicable. We discuss non-invasive assessment of organoids, which can reveal the underlying biological mechanisms and enable improved assays for growth, metabolism, and function. Applications of organoids in cell therapy are also discussed. Taken together, we establish a broad scientific foundation for organoids and provide an in-depth review of hepatic, biliary and pancreatic organoids.     

Revealing the inner workings of organoids

The mechanisms by which human stem cells self‐organise into brain‐like tissues in 3D organoid culture are poorly understood. In this issue of The EMBO Journal, Renner and Lancaster et al demonstrate that in the absence of external stimuli, human cerebral organoids develop large forebrain structures that display specific landmarks of spatial and temporal patterning, including signalling centres producing known morphogens. The generation of cerebral organoids is therefore likely to reflect normal brain development.     

The development of an in vitro cerebral organoid model for investigating the pathomolecular mechanisms associated with the central nervous system involvement in Mitochondrial Neurogastrointestinal Encephalomyopathy (MNGIE)

Abstract

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare disorder caused by mutations in the thymidine phosphorylase gene (TYMP), leading to secondary aberrations to the mitochondrial genome. The disease is characterised by gastrointestinal dysmotility, sensorimotor peripheral neuropathy and leukoencephalopathy. The understanding of the molecular mechanisms that underlie the central nervous system (CNS) is hindered by the lack of a representative disease model; to address this we have developed an in vitro 3-D cerebral organoid of MNGIE. Induced pluripotent stem cells (iPSCs) generated from peripheral blood mononuclear cells (PBMCs) of a healthy control and a patient with MNGIE were characterised to ascertain bona fide pluripotency through the evaluation of pluripotency markers and the differentiation to the germ layers. iPSC lines were differentiated into cerebral organoids. Thymidine phosphorylase expression in PBMCs, iPSCs and Day 92 organoids was evaluated by immunoblotting and intact organoids were sampled for histological evaluation of neural markers. iPSCs demonstrated the expression of pluripotency markers SOX2 and TRA1-60 and the plasticity to differentiate into the germ layers. Cerebral organoids stained positive for the neural markers GFAP, O4, Tuj1, Nestin, SOX2 and MBP. Consistent with the disease phenotypes, MNGIE cells did not display thymidine phosphorylase expression whereas control PBMCs and Day 92 organoids did. Remarkably, control iPSCs did not stain positive for thymidine phosphorylase. We have established for the first time a MNGIE iPSC line and cerebral organoid model, which exhibited the expression of cells relevant to the study of the disease, such as neural stem cells, astrocytes and myelinating oligodendrocytes.