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Lipid Droplet Accumulation in Human Pancreatic Islets Is Dependent On Both Donor Age and Health.
Tong X, Dai C, Walker JT, Nair GG, Kennedy A, Carr RM, Hebrok M, Powers AC, Stein R
(2020) Diabetes 69: 342-354
MeSH Terms: Acinar Cells, Adolescent, Adult, Age Factors, Aged, Animals, Child, Child, Preschool, Diabetes Mellitus, Experimental, Diabetes Mellitus, Type 2, Embryonic Stem Cells, Female, Glucagon-Secreting Cells, Humans, Infant, Insulin-Secreting Cells, Islets of Langerhans, Islets of Langerhans Transplantation, Lipid Droplets, Male, Mice, Microscopy, Electron, Microscopy, Fluorescence, Middle Aged, Rats, Tissue Donors, Young Adult
Show Abstract · Added March 29, 2020
Human but not mouse islets transplanted into immunodeficient NSG mice effectively accumulate lipid droplets (LDs). Because chronic lipid exposure is associated with islet β-cell dysfunction, we investigated LD accumulation in the intact human and mouse pancreas over a range of ages and states of diabetes. Very few LDs were found in normal human juvenile pancreatic acinar and islet cells, with numbers subsequently increasing throughout adulthood. While accumulation appeared evenly distributed in postjuvenile acinar and islet cells in donors without diabetes, LDs were enriched in islet α- and β-cells from donors with type 2 diabetes (T2D). LDs were also found in the islet β-like cells produced from human embryonic cell-derived β-cell clusters. In contrast, LD accumulation was nearly undetectable in the adult rodent pancreas, even in hyperglycemic and hyperlipidemic models or 1.5-year-old mice. Taken together, there appear to be significant differences in pancreas islet cell lipid handling between species, and the human juvenile and adult cell populations. Moreover, our results suggest that LD enrichment could be impactful to T2D islet cell function.
© 2019 by the American Diabetes Association.
0 Communities
1 Members
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27 MeSH Terms
B lymphocytes protect islet β cells in diabetes prone NOD mice treated with imatinib.
Wilson CS, Spaeth JM, Karp J, Stocks BT, Hoopes EM, Stein RW, Moore DJ
(2019) JCI Insight 5:
MeSH Terms: Animals, Autoimmunity, B-Lymphocytes, Cell Proliferation, Diabetes Mellitus, Type 1, Disease Models, Animal, Homeodomain Proteins, Hyperglycemia, Imatinib Mesylate, Insulin, Insulin-Secreting Cells, Islets of Langerhans, Maf Transcription Factors, Large, Mice, Mice, Inbred C57BL, Mice, Inbred NOD, Mice, Knockout
Show Abstract · Added April 10, 2019
Imatinib (Gleevec) reverses type 1 diabetes (T1D) in NOD mice and is currently in clinical trials in individuals with recent-onset disease. While research has demonstrated that imatinib protects islet β cells from the harmful effects of ER stress, the role the immune system plays in its reversal of T1D has been less well understood, and specific cellular immune targets have not been identified. In this study, we demonstrate that B lymphocytes, an immune subset that normally drives diabetes pathology, are unexpectedly required for reversal of hyperglycemia in NOD mice treated with imatinib. In the presence of B lymphocytes, reversal was linked to an increase in serum insulin concentration, but not an increase in islet β cell mass or proliferation. However, improved β cell function was reflected by a partial recovery of MafA transcription factor expression, a sensitive marker of islet β cell stress that is important to adult β cell function. Imatinib treatment was found to increase the antioxidant capacity of B lymphocytes, improving reactive oxygen species (ROS) handling in NOD islets. This study reveals a novel mechanism through which imatinib enables B lymphocytes to orchestrate functional recovery of T1D β cells.
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17 MeSH Terms
Imaging mass spectrometry enables molecular profiling of mouse and human pancreatic tissue.
Prentice BM, Hart NJ, Phillips N, Haliyur R, Judd A, Armandala R, Spraggins JM, Lowe CL, Boyd KL, Stein RW, Wright CV, Norris JL, Powers AC, Brissova M, Caprioli RM
(2019) Diabetologia 62: 1036-1047
MeSH Terms: Animals, Fluorescent Antibody Technique, Gangliosides, Humans, Immunohistochemistry, Islets of Langerhans, Mice, Pancreas, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
Show Abstract · Added May 7, 2019
AIMS/HYPOTHESIS - The molecular response and function of pancreatic islet cells during metabolic stress is a complex process. The anatomical location and small size of pancreatic islets coupled with current methodological limitations have prevented the achievement of a complete, coherent picture of the role that lipids and proteins play in cellular processes under normal conditions and in diseased states. Herein, we describe the development of untargeted tissue imaging mass spectrometry (IMS) technologies for the study of in situ protein and, more specifically, lipid distributions in murine and human pancreases.
METHODS - We developed matrix-assisted laser desorption/ionisation (MALDI) IMS protocols to study metabolite, lipid and protein distributions in mouse (wild-type and ob/ob mouse models) and human pancreases. IMS allows for the facile discrimination of chemically similar lipid and metabolite isoforms that cannot be distinguished using standard immunohistochemical techniques. Co-registration of MS images with immunofluorescence images acquired from serial tissue sections allowed accurate cross-registration of cell types. By acquiring immunofluorescence images first, this serial section approach guides targeted high spatial resolution IMS analyses (down to 15 μm) of regions of interest and leads to reduced time requirements for data acquisition.
RESULTS - MALDI IMS enabled the molecular identification of specific phospholipid and glycolipid isoforms in pancreatic islets with intra-islet spatial resolution. This technology shows that subtle differences in the chemical structure of phospholipids can dramatically affect their distribution patterns and, presumably, cellular function within the islet and exocrine compartments of the pancreas (e.g. 18:1 vs 18:2 fatty acyl groups in phosphatidylcholine lipids). We also observed the localisation of specific GM3 ganglioside lipids [GM3(d34:1), GM3(d36:1), GM3(d38:1) and GM3(d40:1)] within murine islet cells that were correlated with a higher level of GM3 synthase as verified by immunostaining. However, in human pancreas, GM3 gangliosides were equally distributed in both the endocrine and exocrine tissue, with only one GM3 isoform showing islet-specific localisation.
CONCLUSIONS/INTERPRETATION - The development of more complete molecular profiles of pancreatic tissue will provide important insight into the molecular state of the pancreas during islet development, normal function, and diseased states. For example, this study demonstrates that these results can provide novel insight into the potential signalling mechanisms involving phospholipids and glycolipids that would be difficult to detect by targeted methods, and can help raise new hypotheses about the types of physiological control exerted on endocrine hormone-producing cells in islets. Importantly, the in situ measurements afforded by IMS do not require a priori knowledge of molecules of interest and are not susceptible to the limitations of immunohistochemistry, providing the opportunity for novel biomarker discovery. Notably, the presence of multiple GM3 isoforms in mouse islets and the differential localisation of lipids in human tissue underscore the important role these molecules play in regulating insulin modulation and suggest species, organ, and cell specificity. This approach demonstrates the importance of both high spatial resolution and high molecular specificity to accurately survey the molecular composition of complex, multi-functional tissues such as the pancreas.
1 Communities
4 Members
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9 MeSH Terms
p120ctn-Mediated Organ Patterning Precedes and Determines Pancreatic Progenitor Fate.
Nyeng P, Heilmann S, Löf-Öhlin ZM, Pettersson NF, Hermann FM, Reynolds AB, Semb H
(2019) Dev Cell 49: 31-47.e9
MeSH Terms: Animals, Body Patterning, Cadherins, Catenins, Cell Differentiation, Cell Lineage, Cell Movement, Embryonic Development, Flow Cytometry, Gene Expression Regulation, Developmental, Humans, Islets of Langerhans, Mice, Pancreas, Pancreatic Ducts, Receptors, Notch, Signal Transduction, Stem Cells
Show Abstract · Added March 29, 2019
The mechanism of how organ shape emerges and specifies cell fate is not understood. Pancreatic duct and endocrine lineages arise in a spatially distinct domain from the acinar lineage. Whether these lineages are pre-determined or settle once these niches have been established remains unknown. Here, we reconcile these two apparently opposing models, demonstrating that pancreatic progenitors re-localize to establish the niche that will determine their ultimate fate. We identify a p120ctn-regulated mechanism for coordination of organ architecture and cellular fate mediated by differential E-cadherin based cell sorting. Reduced p120ctn expression is necessary and sufficient to re-localize a subset of progenitors to the peripheral tip domain, where they acquire an acinar fate. The same mechanism is used re-iteratively during endocrine specification, where it balances the choice between the alpha and beta cell fates. In conclusion, organ patterning is regulated by p120ctn-mediated cellular positioning, which precedes and determines pancreatic progenitor fate.
Copyright © 2019 Elsevier Inc. All rights reserved.
1 Communities
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18 MeSH Terms
Beta cell secretion of miR-375 to HDL is inversely associated with insulin secretion.
Sedgeman LR, Beysen C, Ramirez Solano MA, Michell DL, Sheng Q, Zhao S, Turner S, Linton MF, Vickers KC
(2019) Sci Rep 9: 3803
MeSH Terms: Animals, Biological Transport, Cell Cycle, Humans, Insulin, Insulin Secretion, Insulin-Secreting Cells, Islets of Langerhans, Lipoproteins, HDL, Mice, Mice, Transgenic, MicroRNAs
Show Abstract · Added April 10, 2019
Extracellular microRNAs (miRNAs) are a new class of biomarkers for cellular phenotypes and disease, and are bioactive signals within intercellular communication networks. Previously, we reported that miRNAs are secreted from macrophage to high-density lipoproteins (HDL) and delivered to recipient cells to regulate gene expression. Despite the potential importance of HDL-miRNAs, regulation of HDL-miRNA export from cells has not been fully studied. Here, we report that pancreatic islets and beta cells abundantly export miR-375-3p to HDL and this process is inhibited by cellular mechanisms that promote insulin secretion. Small RNA sequencing and PCR approaches were used to quantify beta cell miRNA export to HDL. Strikingly, high glucose conditions were found to inhibit HDL-miR-375-3p export, which was dependent on extracellular calcium. Likewise, stimulation of cAMP was found to repress HDL-miR-375-3p export. Furthermore, we found that beta cell ATP-sensitive potassium channel (K) channels are required for HDL-miRNA export as chemical inhibition (tolbutamide) and global genetic knockout (Abcc8) approaches inhibited HDL-miR-375-3p export. This process is not likely associated with cholesterol flux, as gain-of-function and loss-of-function studies for cholesterol transporters failed to alter HDL-miR-375-3p export. In conclusion, results support that pancreatic beta cells export miR-375-3p to HDL and this process is inversely regulated to insulin secretion.
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12 MeSH Terms
Neurog3-Independent Methylation Is the Earliest Detectable Mark Distinguishing Pancreatic Progenitor Identity.
Liu J, Banerjee A, Herring CA, Attalla J, Hu R, Xu Y, Shao Q, Simmons AJ, Dadi PK, Wang S, Jacobson DA, Liu B, Hodges E, Lau KS, Gu G
(2019) Dev Cell 48: 49-63.e7
MeSH Terms: Animals, Basic Helix-Loop-Helix Transcription Factors, Cell Differentiation, Cell Lineage, Endocrine Cells, Homeodomain Proteins, Insulin-Secreting Cells, Islets of Langerhans, Mice, Nerve Tissue Proteins, Organogenesis, Pancreas, Transcription Factors
Show Abstract · Added February 6, 2019
In the developing pancreas, transient Neurog3-expressing progenitors give rise to four major islet cell types: α, β, δ, and γ; when and how the Neurog3 cells choose cell fate is unknown. Using single-cell RNA-seq, trajectory analysis, and combinatorial lineage tracing, we showed here that the Neurog3 cells co-expressing Myt1 (i.e., Myt1Neurog3) were biased toward β cell fate, while those not simultaneously expressing Myt1 (Myt1Neurog3) favored α fate. Myt1 manipulation only marginally affected α versus β cell specification, suggesting Myt1 as a marker but not determinant for islet-cell-type specification. The Myt1Neurog3 cells displayed higher Dnmt1 expression and enhancer methylation at Arx, an α-fate-promoting gene. Inhibiting Dnmts in pancreatic progenitors promoted α cell specification, while Dnmt1 overexpression or Arx enhancer hypermethylation favored β cell production. Moreover, the pancreatic progenitors contained distinct Arx enhancer methylation states without transcriptionally definable sub-populations, a phenotype independent of Neurog3 activity. These data suggest that Neurog3-independent methylation on fate-determining gene enhancers specifies distinct endocrine-cell programs.
Published by Elsevier Inc.
1 Communities
1 Members
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13 MeSH Terms
A Call for Improved Reporting of Human Islet Characteristics in Research Articles.
Poitout V, Satin LS, Kahn SE, Stoffers DA, Marchetti P, Gannon M, Verchere CB, Herold KC, Myers MG, Marshall SM
(2019) Diabetes 68: 239-240
MeSH Terms: Humans, Islets of Langerhans, Islets of Langerhans Transplantation
Added April 15, 2019
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1 Members
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3 MeSH Terms
A call for improved reporting of human islet characteristics in research articles.
Poitout V, Satin LS, Kahn SE, Stoffers DA, Marchetti P, Gannon M, Verchere CB, Herold KC, Myers MG, Marshall SM
(2019) Diabetologia 62: 209-211
MeSH Terms: Humans, Islets of Langerhans, Islets of Langerhans Transplantation
Added April 15, 2019
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MeSH Terms
Ectonucleoside Triphosphate Diphosphohydrolase-3 Antibody Targets Adult Human Pancreatic β Cells for In Vitro and In Vivo Analysis.
Saunders DC, Brissova M, Phillips N, Shrestha S, Walker JT, Aramandla R, Poffenberger G, Flaherty DK, Weller KP, Pelletier J, Cooper T, Goff MT, Virostko J, Shostak A, Dean ED, Greiner DL, Shultz LD, Prasad N, Levy SE, Carnahan RH, Dai C, Sévigny J, Powers AC
(2019) Cell Metab 29: 745-754.e4
MeSH Terms: Adenosine Triphosphatases, Adult, Animals, Biomarkers, Cells, Cultured, Diabetes Mellitus, Type 1, Diabetes Mellitus, Type 2, Humans, Insulin-Secreting Cells, Islets of Langerhans, Male, Membrane Proteins, Mice, Mice, Inbred NOD, Pancreas, Young Adult
Show Abstract · Added February 4, 2019
Identification of cell-surface markers specific to human pancreatic β cells would allow in vivo analysis and imaging. Here we introduce a biomarker, ectonucleoside triphosphate diphosphohydrolase-3 (NTPDase3), that is expressed on the cell surface of essentially all adult human β cells, including those from individuals with type 1 or type 2 diabetes. NTPDase3 is expressed dynamically during postnatal human pancreas development, appearing first in acinar cells at birth, but several months later its expression declines in acinar cells while concurrently emerging in islet β cells. Given its specificity and membrane localization, we utilized an NTPDase3 antibody for purification of live human β cells as confirmed by transcriptional profiling, and, in addition, for in vivo imaging of transplanted human β cells. Thus, NTPDase3 is a cell-surface biomarker of adult human β cells, and the antibody directed to this protein should be a useful new reagent for β cell sorting, in vivo imaging, and targeting.
Copyright © 2018 Elsevier Inc. All rights reserved.
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3 Members
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16 MeSH Terms
Pancreatic islet-autonomous insulin and smoothened-mediated signalling modulate identity changes of glucagon α-cells.
Cigliola V, Ghila L, Thorel F, van Gurp L, Baronnier D, Oropeza D, Gupta S, Miyatsuka T, Kaneto H, Magnuson MA, Osipovich AB, Sander M, Wright CEV, Thomas MK, Furuyama K, Chera S, Herrera PL
(2018) Nat Cell Biol 20: 1267-1277
MeSH Terms: Animals, Cell Differentiation, Cell Plasticity, Cell Proliferation, Female, Glucagon-Secreting Cells, Insulin, Insulin-Secreting Cells, Islets of Langerhans, Male, Mice, Inbred C57BL, Mice, Knockout, Mice, SCID, Mice, Transgenic, Signal Transduction, Smoothened Receptor
Show Abstract · Added November 6, 2018
The mechanisms that restrict regeneration and maintain cell identity following injury are poorly characterized in higher vertebrates. Following β-cell loss, 1-2% of the glucagon-producing α-cells spontaneously engage in insulin production in mice. Here we explore the mechanisms inhibiting α-cell plasticity. We show that adaptive α-cell identity changes are constrained by intra-islet insulin- and Smoothened-mediated signalling, among others. The combination of β-cell loss or insulin-signalling inhibition, with Smoothened inactivation in α- or δ-cells, stimulates insulin production in more α-cells. These findings suggest that the removal of constitutive 'brake signals' is crucial to neutralize the refractoriness to adaptive cell-fate changes. It appears that the maintenance of cell identity is an active process mediated by repressive signals, which are released by neighbouring cells and curb an intrinsic trend of differentiated cells to change.
2 Communities
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16 MeSH Terms