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Adrenal chromaffin cells and sympathetic neurons synthesize and release catecholamines, and both cell types are derived from neural crest precursors. However, they have different developmental histories, with sympathetic neurons derived directly from neural crest precursors while adrenal chromaffin cells arise from neural crest-derived cells that express Schwann cell markers. We have sought to identify the genes, including imprinted genes, which regulate the development of the two cell types in mice. We developed a method of separating the two cell types as early as E12.5, using differences in expression of enhanced yellow fluorescent protein driven from the tyrosine hydroxylase gene, and then used RNA sequencing to confirm the characteristic molecular signatures of the two cell types. We identified genes differentially expressed by adrenal chromaffin cells and sympathetic neurons. Deletion of a gene highly expressed by adrenal chromaffin cells, NIK-related kinase, a gene on the X-chromosome, results in reduced expression of adrenaline-synthesizing enzyme, phenyl-N-methyl transferase, by adrenal chromaffin cells and changes in cell cycle dynamics. Finally, many imprinted genes are up-regulated in chromaffin cells and may play key roles in their development.

Intra-tumoural heterogeneity and cancer cell plasticity in colorectal cancer (CRC) have been key challenges to effective treatment for patients. It has been suggested that a subpopulation of LGR5-expressing cancer stem cells (CSCs) is responsible for driving tumour relapse and therapy resistance in CRC. However, studies have revealed that the LGR5+ve CSC population is highly sensitive to chemotherapy. It has been hypothesised that another subset of tumour cells can phenotypically revert to a stem-like state in response to chemotherapy treatment which replenishes the LGR5+ve CSC population and maintains tumour growth. Recently, a unique stem cell population marked by enriched clusterin (CLU) expression and termed the revival stem cell (RevSC) was identified in the regenerating murine intestine. This CLU-expressing cell population is quiescent during homeostasis but has the ability to survive and regenerate other stem cells upon injury. More recently, the CLU+ve signature has been implicated in several adverse outcomes in CRC, including chemotherapy resistance and poor patient survival; however, the mechanism behind this remains undetermined. In this review, we discuss recent insights on CLU in CRC and its roles in enhancing the plasticity of cells and further consider the implications of CLU as a prospective target for therapeutic intervention.

Representative models of intestinal diseases are transforming our knowledge of the molecular mechanisms of disease, facilitating effective drug screening and avenues for personalised medicine. Despite the emergence of 3D in vitro intestinal organoid culture systems that replicate the genetic and functional characteristics of the epithelial tissue of origin, there are still challenges in reproducing the human physiological tissue environment in a format that enables functional readouts. Here, we describe the latest platforms engineered to investigate environmental tissue impacts, host-microbe interactions and enable drug discovery. This highlights the potential to revolutionise knowledge on the impact of intestinal infection and inflammation and enable personalised disease modelling and clinical translation.

Epidermal Growth Factor (EGF) has long been known for its role in promoting proliferation of intestinal epithelial cells. EGF is produced by epithelial niche cells at the base of crypts in vivo and is routinely added to the culture medium to support the growth of intestinal organoids ex vivo . The recent identification of diverse stromal cell populations that reside underneath intestinal crypts has enabled the characterization of key growth factor cues supplied by these cells. The nature of these signals and how they are delivered to drive intestinal epithelial development, daily homeostasis and tissue regeneration following injury are being investigated. It is clear that aside from EGF, other ligands of the family, including Neuregulin 1 (NRG1), have distinct roles in supporting the function of intestinal stem cells through the ErbB pathway.

Organoids are three‐dimensional self‐renewing and organizing clusters of cells that recapitulate the behavior and functionality of developed organs. Referred to as “organs in a dish,” organoids are invaluable biological models for disease modeling or drug screening. Currently, organoid culture commonly relies on an expensive and undefined tumor‐derived reconstituted basal membrane which hinders its application in high‐throughput screening, regenerative medicine, and diagnostics. Here, we introduce a novel engineered plant‐based nanocellulose hydrogel is introduced as a well‐defined and low‐cost matrix that supports organoid growth. Gels containing 0.1% nanocellulose fibers (99.9% water) are ionically crosslinked and present mechanical properties similar to the standard animal‐based matrix. The regulation of the osmotic pressure is performed by a salt‐free strategy, offering conditions for cell survival and proliferation. Cellulose nanofibers are functionalized with fibronectin‐derived adhesive sites to provide the required microenvironment for small intestinal organoid growth and budding. Comparative transcriptomic profiling reveals a good correlation with transcriptome‐wide gene expression pattern between organoids cultured in both materials, while differences are observed in stem cells‐specific marker genes. These hydrogels are tunable and can be combined with laminin‐1 and supplemented with insulin‐like growth factor (IGF‐1) to optimize the culture conditions. Nanocellulose hydrogel emerges as a promising matrix for the growth of organoids. Plant‐based nanocellulose hydrogel is introduced as a well‐defined and very low‐cost porous nanofibrous matrix that supports organoid growth. The mechanical, chemical, and biological properties of the gel are engineered to mimic the extracellular matrix (ECM), providing the required microenvironment for small intestinal organoid culture. This performant hydrogel is tunable with ECM‐derived components, emerging as a promising biomaterial for organoid systems.

Colorectal cancer stem cells have been proposed to drive disease progression, tumour recurrence and chemoresistance. However, studies ablating leucine rich repeat containing G protein-coupled receptor 5 (LGR5)-positive stem cells have shown that they are rapidly replenished in primary tumours. Following injury in normal tissue, LGR5+ stem cells are replaced by a newly defined, transient population of revival stem cells. We investigated whether markers of the revival stem cell population are present in colorectal tumours and how this signature relates to chemoresistance. We examined the expression of different stem cell markers in a cohort of patient-derived colorectal cancer organoids and correlated expression with sensitivity to 5-fluorouracil (5-FU) treatment. Our findings revealed that there was inter-tumour variability in the expression of stem cell markers. Clusterin (CLU), a marker of the revival stem cell population, was significantly enriched following 5-FU treatment and expression correlated with the level of drug resistance. Patient outcome data revealed that CLU expression is associated with both lower patient survival and an increase in disease recurrence. This suggests that CLU is a marker of drug resistance and may identify cells that drive colorectal cancer progression.

Ciguatera fish poisoning (CFP) is a global foodborne illness caused by consumption of seafood containing ciguatoxins (CTXs) originating from dinoflagellates such as Gambierdiscus toxicus. P-CTX-1 has been suggested to be the most toxic CTX, causing ciguatera at 0.1 μg/kg in the flesh of carnivorous fish. CTXs are structurally complex and difficult to quantify, but there is a need for analytical methods for CFP toxins in coral reef fishes to protect human health. In this paper, we describe a sensitive and rapid extraction method using accelerated solvent extraction combined with high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS) for the detection and quantification of P-CTX-1 in fish flesh. By the use of a more sensitive MS system (5500 QTRAP), the validated method has a limit of quantification (LOQ) of 0.01 μg/kg, linearity correlation coefficients above 0.99 for both solvent- and matrix-based standard solutions as well as matrix spike recoveries ranging from 49% to 85% in 17 coral reef fish species. Compared with previous methods, this method has better overall recovery, extraction efficiency and LOQ. Fish flesh from 12 blue-spotted groupers (Cephalopholis argus) was assessed for the presence of CTXs using HPLC-MS/MS analysis and the commonly used mouse neuroblastoma assay, and the results of the two methods were strongly correlated. This method is capable of detecting low concentrations of P-CTX-1 in fish at levels that are relevant to human health, making it suitable for monitoring of suspected ciguateric fish both in the environment and in the marketplace.

Background Learning about occupational therapy theories is crucial to occupational therapy education, and an online database is developed to facilitate students’ learning of occupational therapy theories in this study. Aim This study was conducted to evaluate the effect of this database on users’ experiences. Methods A mixed-method approach, including surveys and focus groups, was used. First- and third-year students who had studied occupational therapy theory at a university participated in this study. Results One-hundred-and-twenty students completed the surveys, and 11 students participated in the focus groups. The students demonstrated a significant increase in the number of theories they named and their perceived understanding of theories after the semester. They rated the content, utility and satisfaction with the database in facilitating their understanding/learning of theories as moderate-good. Based on qualitative data, it appeared that the database provided specific information about occupational therapy theories and facilitated students’ learning and level of interest in learning about them. However, the first-year students who accessed the database showed a significantly decreased level of interest in learning about theories, but such the decrease was not found in the third-year students. Conclusion The study findings suggest that the use of an online database may enhance students' learning about occupational therapy theories in educational settings.

Ciguatera fish poisoning (CFP) is a food intoxication caused by exposure to ciguatoxins (CTXs) in coral reef fish. Rapid analytical methods have been developed recently to quantify Pacific-CTX-1 (P-CTX-1) in fish muscle, but it is destructive and can cause harm to valuable live coral reef fish. Also fish muscle extract was complex making CTX quantification challenging. Not only P-CTX-1, but also P-CTX-2 and P-CTX-3 could be present in fish, contributing to ciguatoxicity. Therefore, an analytical method for simultaneous quantification of P-CTX-1, P-CTX-2, and P-CTX-3 in whole blood of marketed coral reef fish using sonication, solid-phase extraction (SPE), and liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed. The optimized method gave acceptable recoveries of P-CTXs (74–103 %) in fish blood. Matrix effects (6–26 %) in blood extracts were found to be significantly reduced compared with those in muscle extracts (suppressed by 34–75 % as reported in other studies), thereby minimizing potential for false negative results. The target P-CTXs were detectable in whole blood from four coral reef fish species collected in a CFP-endemic region. Similar trends in total P-CTX levels and patterns of P-CTX composition profiles in blood and muscle of these fish were observed, suggesting a relationship between blood and muscle levels of P-CTXs. This optimized method provides an essential tool for studies of P-CTX pharmacokinetics and pharmacodynamics in fish, which are needed for establishing the use of fish blood as a reliable sample for the assessment and control of CFP. Figure Chromatograph of P-CTXs in whole blood of wild-caught moray eel

Inflammatory bowel disease (IBD) is secondary to an abnormal immune response to the microbiota. To study this, models of host-microbe interactions that represent mucosal bacterial communities and inter-patient diversity are required. Human intestinal organoids (HIOs) are an established model to investigate epithelial responses. Here, we describe a technique of culturing bacteria directly from the sites of inflammation in IBD, while simultaneously sampling host tissue. We generated HIOs from a cohort of newly diagnosed paediatric IBD patients, without confounding treatments or comorbidities, and explored their response to site-specific bacteria. A unique biobank of matched HIOs and cultured mucosa-attached bacteria was established from 27 paediatric patients. Transcriptional profiling revealed differential gene expression between control and IBD-derived organoids. We used microinjection to introduce bacteria to the apical surface of the epithelium, to determine the effect of bacteria on host epithelial cells. We measured survival and growth of bacteria within the HIOs and tested several related bacterial isolates for their impact on the epithelium. An isolate from a control patient stimulated inflammatory signalling pathways but this was not observed in response to a closely related isolate originating from an IBD patient. This study demonstrates the feasibility of isolating bacteria and generating organoids from the same biopsy tissue, to explore personalised host-microbe interactions. The microinjections, while labour-intensive, demonstrate that closely related bacteria can induce very different epithelial responses, with downstream implications for immune response. This highlights the importance of understanding host-microbe interactions in a strain- and site-specific manner and developing techniques for personalised microbiome-based therapeutics.