Navigating the Depths and Avoiding the Shallows of Pancreatic Islet Cell Transcriptomes.
Ontology highlight
ABSTRACT:
SUBMITTER: Mawla AM
PROVIDER: S-EPMC6609986 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Pancreatic islets of Langerhans contain several specialized endocrine cell types, which are commonly identified by the expression of single marker genes. However, the established marker genes cannot capture the complete spectrum of cellular heterogeneity in human pancreatic islets, and existing bulk transcriptome datasets provide averages across several cell populations. To dissect the cellular composition of the human pancreatic islet and to establish transcriptomes for all major cell types, we performed single-cell RNA sequencing on 70 cells sorted from human primary tissue. We used this dataset to validate previously described marker genes at the single-cell level and to identify specifically expressed transcription factors for all islet cell subtypes. All data are available for browsing and download, thus establishing a useful resource of single-cell expression profiles for endocrine cells in human pancreatic islets.
| S-EPMC4784001 | biostudies-literature
Project description:Individuals with balance and gait problems encounter additional challenges navigating this post-coronavirus disease-2019 (COVID-19) world. All but the best fitting facemasks partially obscure the lower visual field. Facemask use by individuals with balance and gait problems has the potential to further compromise walking safety. More broadly, as the world reopens for business, balance and gait testing in clinics and research laboratories will also be impacted by facemask use. Here, we highlight some of the challenges faced by patients, clinicians, and researchers as they return to "normal" after COVID-19.Video Abstract is available for insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A328.
| S-EPMC7737700 | biostudies-literature
Project description:Human pancreatic islets engrafted into immunodeficient mice serve as an important model for in vivo human diabetes studies. Following engraftment, islet function can be monitored in vivo by measuring circulating glucose and human insulin; however, it will be important to recover viable cells for more complex graft analyses. Moreover, RNA analyses of dissected grafts have not distinguished which hormone-specific cell types contribute to gene expression. We developed a method for recovering live cells suitable for fluorescence-activated cell sorting from human islets engrafted in mice. Although yields of recovered islet cells were relatively low, the ratios of bulk-sorted ?, ?, and ? cells and their respective hormone-specific RNA-Seq transcriptomes are comparable pretransplant and posttransplant, suggesting that the cellular characteristics of islet grafts posttransplant closely mirror the original donor islets. Single-cell RNA-Seq transcriptome analysis confirms the presence of appropriate ?, ?, and ? cell subsets. In addition, ex vivo perifusion of recovered human islet grafts demonstrated glucose-stimulated insulin secretion. Viable cells suitable for patch-clamp analysis were recovered from transplanted human embryonic stem cell-derived ? cells. Together, our functional and hormone-specific transcriptome analyses document the broad applicability of this system for longitudinal examination of human islet cells undergoing developmental/metabolic/pharmacogenetic manipulation in vivo and may facilitate the discovery of treatments for diabetes.
| S-EPMC6972551 | biostudies-literature
Project description:We and others have previously identified a group of genes, dubbed "disallowed," whose expression is markedly lower in pancreatic islets than in other mammalian cell types. Forced mis-expression of several members of this family leads to defective insulin secretion, demonstrating the likely importance of disallowance for normal beta cell function. Up to now, transcriptomic comparisons have been based solely on data from whole islets. This raises the possibilities that (a) there may be important differences in the degree of disallowance of family members between beta and other either neuroendocrine cells; (b) beta (or alpha) cell disallowed genes may have gone undetected. To address this issue, we survey here recent massive parallel sequencing (RNA-Seq) datasets from purified mouse and human islet cells. Our analysis reveals that the most strongly disallowed genes are similar in beta and alpha cells, with 11β-hydroxysteroid dehydrogenase (Hsd11b1) mRNA being essentially undetectable in both cell types. The analysis also reveals that several genes involved in cellular proliferation, including Yap1 and Igfbp4, and previously assumed to be disallowed in both beta and alpha cells, are selectively repressed only in the beta cell. The latter finding supports the view that beta cell growth is selectively restricted in adults, providing a mechanism to avoid excessive insulin production and the risk of hypoglycaemia. Approaches which increase the expression or activity of selected disallowed genes in the beta cell may provide the basis for novel regenerative therapies in type 2 diabetes.
| S-EPMC5385341 | biostudies-literature
Project description:BACKGROUND: Islet 1 (ISL1), a LIM-homeodomain transcription factor is essential for promoting pancreatic islets proliferation and maintaining endocrine cells survival in embryonic and postnatal pancreatic islets. However, how ISL1 exerts the role in adult islets is, to date, not clear. METHODOLOGY/PRINCIPAL FINDINGS: Our results show that ISL1 expression was up-regulated at the mRNA level both in cultured pancreatic cells undergoing glucose oxidase stimulation as well in type 1 and type 2 diabetes mouse models. The knockdown of ISL1 expression increased the apoptosis level of HIT-T15 pancreatic islet cells. Using HIT-T15 and primary adult islet cells as cell models, we show that ISL1 promoted adult pancreatic islet cell proliferation with increased c-Myc and CyclinD1 transcription, while knockdown of ISL1 increased the proportion of cells in G(1) phase and decreased the proportion of cells in G(2)/M and S phases. Further investigation shows that ISL1 activated both c-Myc and CyclinD1 transcription through direct binding on their promoters. CONCLUSIONS/SIGNIFICANCE: ISL1 promoted adult pancreatic islet cell proliferation and probably by activating c-Myc and CyclinD1 transcription through direct binding on their promoters. Our findings extend the knowledge about the crucial role of ISL1 in maintaining mature islet cells homeostasis. Our results also provide insights into the new regulation relationships between ISL1 and other growth factors.
| S-EPMC3150357 | biostudies-other
Project description:Human pluripotent stem cells (PSCs), including human embryonic stem cells and induced pluripotent stem cells, are promising cell sources in regenerating pancreatic islets through in vitro directed differentiation. Recent progress in this research field has made it possible to generate glucose-responsive pancreatic islet cells from PSCs. Single-cell RNA sequencing techniques have been applied to analyze PSC-derived endocrine beta-cells, which are then compared with human islets. This has led to the identification of novel signaling pathways and molecules involved in lineage commitment during pancreatic differentiation and maturation processes. Single-cell transcriptomics are also used to construct a detailed map of in vivo endocrine differentiation of developing mouse embryos to study pancreatic islet development. Mimicking those occurring in vivo, it was reported that differentiating PSCs can generate similar islet cell structures, while metabolomics analysis highlighted key components involved in PSC-derived pancreatic islet cell function, providing information for the improvement of in vitro pancreatic maturation procedures. In addition, cell transplantation into diabetic animal models, together with the cell delivery system, is studied to ensure the therapeutic potentials of PSC-derived pancreatic islet cells. Combined with gene-editing technology, the engineered mutation-corrected PSC lines originated from diabetes patients could be differentiated into functional pancreatic islet cells, suggesting possible autologous cell therapy in the future. These PSC-derived pancreatic islet cells are a potential tool for studies of disease modeling and drug testing. Herein, we outlined the directed differentiation procedures of PSC-derived pancreatic islet cells, novel findings through transcriptome and metabolome studies, and recent progress in disease modeling.
| S-EPMC7784351 | biostudies-literature
Project description:Maintenance of the pancreatic acinar cell phenotype suppresses tumor formation. Hence, repetitive acute or chronic pancreatitis, stress conditions in which the acinar cells dedifferentiate, predispose for cancer formation in the pancreas. Dedifferentiated acinar cells acquire a large panel of duct cell-specific markers. However, it remains unclear to what extent dedifferentiated acini differ from native duct cells and which genes are uniquely regulating acinar cell dedifferentiation. Moreover, most studies have been performed on mice since the availability of human cells is scarce. Here, we applied a non-genetic lineage tracing method of human pancreatic exocrine acinar and duct cells that allowed cell-type-specific gene expression profiling by RNA sequencing. Subsequent to this discovery analysis, one transcription factor that was unique for dedifferentiated acinar cells was functionally characterized. RNA sequencing analysis showed that human dedifferentiated acinar cells expressed genes in "Pathways of cancer" with a prominence of MECOM (EVI-1), a transcription factor that was not expressed by duct cells. During mouse embryonic development, pre-acinar cells also transiently expressed MECOM and in the adult mouse pancreas, MECOM was re-expressed when mice were subjected to acute and chronic pancreatitis, conditions in which acinar cells dedifferentiate. In human cells and in mice, MECOM expression correlated with and was directly regulated by SOX9. Mouse acinar cells that, by genetic manipulation, lose the ability to upregulate MECOM showed impaired cell adhesion, more prominent acinar cell death, and suppressed acinar cell dedifferentiation by limited ERK signaling. In conclusion, we transcriptionally profiled the two major human pancreatic exocrine cell types, acinar and duct cells, during experimental stress conditions. We provide insights that in dedifferentiated acinar cells, cancer pathways are upregulated in which MECOM is a critical regulator that suppresses acinar cell death by permitting cellular dedifferentiation.
| S-EPMC8408219 | biostudies-literature
Project description:We sought to determine the mRNA transcriptome of all major human pancreatic endocrine and exocrine cell subtypes, including human alpha, beta, duct and acinar cells. In addition, we identified the cell type-specific distribution of transcription factors, signalling ligands and their receptors.Islet samples from healthy human donors were enzymatically dispersed to single cells and labelled with cell type-specific surface-reactive antibodies. Live endocrine and exocrine cell subpopulations were isolated by FACS and gene expression analyses were performed using microarray analysis and quantitative RT-PCR. Computational tools were used to evaluate receptor-ligand representation in these populations.Analysis of the transcriptomes of alpha, beta, large duct, small duct and acinar cells revealed previously unrecognised gene expression patterns in these cell types, including transcriptional regulators HOPX and HDAC9 in the human beta cell population. The abundance of some regulatory proteins was different from that reported in mouse tissue. For example, v-maf musculoaponeurotic fibrosarcoma oncogene homologue B (avian) (MAFB) was detected at equal levels in adult human alpha and beta cells, but is absent from adult mouse beta cells. Analysis of ligand-receptor interactions suggested that EPH receptor-ephrin communication between exocrine and endocrine cells contributes to pancreatic function.This is the first comprehensive analysis of the transcriptomes of human exocrine and endocrine pancreatic cell types-including beta cells-and provides a useful resource for diabetes research. In addition, paracrine signalling pathways within the pancreas are shown. These results will help guide efforts to specify human beta cell fate by embryonic stem cell or induced pluripotent stem cell differentiation or genetic reprogramming.
| S-EPMC3880150 | biostudies-literature
Project description:The mechanisms responsible for initiating autoimmune diabetes remain obscure. Here, we describe a method for identifying both the alpha- and beta-chains of the T cell receptor (TCR) from individual pancreatic islet-infiltrating T cells at the earliest stages of disease in nonobese diabetic mice (NOD). Analysis of the TCR repertoire of these early islet infiltrates reveals enrichment for a small subset of TCR sequences. Reconstitution of these TCR in vitro demonstrates that these receptors confer reactivity to islet cells but not to the well characterized autoantigens, glutamic acid decarboxylase (GAD65) and insulin. Thus, autoimmune diabetes in NOD may be initiated by a limited number of antigens distinct from GAD65 and insulin.
| S-EPMC123148 | biostudies-literature
Project description:Advanced imaging techniques have become a valuable tool in the study of complex biological processes at the cellular level in biomedical research. Here, we introduce a new technical platform for noninvasive in vivo fluorescence imaging of pancreatic islets using the anterior chamber of the eye as a natural body window. Islets transplanted into the mouse eye engrafted on the iris, became vascularized, retained cellular composition, responded to stimulation and reverted diabetes. Laser-scanning microscopy allowed repetitive in vivo imaging of islet vascularization, beta cell function and death at cellular resolution. Our results thus establish the basis for noninvasive in vivo investigations of complex cellular processes, like beta cell stimulus-response coupling, which can be performed longitudinally under both physiological and pathological conditions.
| S-EPMC3538807 | biostudies-literature