scholarly journals Cyanidin-3-O-Glucoside improves the viability of human islet cells treated with amylin or Aβ1-42 in vitro

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258208
Author(s):  
Jennifer Croden ◽  
Josue Rodrigues Silva ◽  
Wenlong Huang ◽  
Nancy Gupta ◽  
Wen Fu ◽  
...  
Keyword(s):  
Cell Viability ◽  
Islet Cells ◽  
Human Islets ◽  
Amyloid Formation ◽  
Post Transplant ◽  
Anti Oxidant ◽  
And Function ◽  
Human Amylin

Islet transplantation is being considered as an alternative treatment for type 1 diabetes. Despite recent progress, transplant recipients continue to experience progressive loss of insulin independence. Cyanidin-3-O-Glucoside (C3G) has shown to be protective against damage that may lead to post-transplant islet loss. In this study, human islets cultured with or without C3G were treated with human amylin, Aβ1-42, H2O2, or rapamycin to mimic stresses encountered in the post-transplant environment. Samples of these islets were collected and assayed to determine C3G’s effect on cell viability and function, reactive oxygen species (ROS), oxidative stress, amyloid formation, and the presence of inflammatory as well as autophagic markers. C3G treatment of human islets exposed to either amylin or Aβ1-42 increased cell viability (p<0.01) and inhibited amyloid formation (p<0.01). A reduction in ROS and an increase in HO-1 gene expression as well as in vitro islet function were also observed in C3G-treated islets exposed to amylin or Aβ1-42, although not significantly. Additionally, treatment with C3G resulted in a significant reduction in the protein expression of inflammatory markers IL-1β and NLRP3 (p<0.01) as well as an increase in LC3 autophagic marker (p<0.05) in human islets treated with amylin, Aβ1-42, rapamycin, or H2O2. Thus, C3G appears to have a multi-faceted protective effect on human islets in vitro, possibly through its anti-oxidant property and alteration of inflammatory as well as autophagic pathways.

scholarly journals Chronic marijuana usage by human pancreas donors is associated with impaired islet function

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258434
Author(s):  
Meirigeng Qi ◽  
John S. Kaddis ◽  
Kuan-Tsen Chen ◽  
Jeffrey Rawson ◽  
Keiko Omori ◽  
...  
Keyword(s):  
High Glucose ◽  
Cannabinoid Receptor ◽  
Marijuana Use ◽  
Human Islets ◽  
Immunofluorescent Staining ◽  
Human Pancreas ◽  
And Function

We investigated the effect of chronic marijuana use, defined as 4 times weekly for more than 3 years, on human pancreatic islets. Pancreata from deceased donors who chronically used marijuana were compared to those from age, sex and ethnicity matched non-users. The islets from marijuana-users displayed reduced insulin secretion as compared to islets from non-users upon stimulation with high glucose (AUC, 3.41 ± 0.62 versus 5.14 ±0.47, p<0.05) and high glucose plus KCl (AUC, 4.48 ± 0.41 versus 7.69 ± 0.58, p<0.001). When human islets from chronic marijuana-users were transplanted into diabetic mice, the mean reversal rate of diabetes was 35% versus 77% in animals receiving islets from non-users (p<0.01). Immunofluorescent staining for cannabinoid receptor type 1 (CB1R) was shown to be colocalized with insulin and enhanced significantly in beta cells from marijuana-users vs. non-users (CB1R intensity/islet area, 14.95 ± 2.71 vs. 3.23 ± 0.87, p<0.001). In contrast, CB1R expression was not co-localized with glucagon or somatostatin. Furthermore, isolated islets from chronic marijuana-users appeared hypertrophic. In conclusion, excessive marijuana use affects islet endocrine phenotype and function in vitro and in vivo. Given the increasing use of marijuana, our results underline the importance of including lifestyle when evaluating human islets for transplantation or research.

scholarly journals BHLHE40 Regulates IL-10 and IFN-γ Production in T Cells but Does Not Interfere With Human Type 1 Regulatory T Cell Differentiation

2021 ◽  
Vol 12 ◽  
Author(s):  
Molly Javier Uyeda ◽  
Robert A. Freeborn ◽  
Brandon Cieniewicz ◽  
Rosa Romano ◽  
Ping (Pauline) Chen ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Differentiation ◽  
Ex Vivo ◽  
Surface Expression ◽  
Surface Molecules ◽  
Ifn Γ ◽  
And Function ◽  
Tr1 Cells

Type 1 regulatory T (Tr1) cells are subset of peripherally induced antigen-specific regulatory T cells. IL-10 signaling has been shown to be indispensable for polarization and function of Tr1 cells. However, the transcriptional machinery underlying human Tr1 cell differentiation and function is not yet elucidated. To this end, we performed RNA sequencing on ex vivo human CD49b+LAG3+ Tr1 cells. We identified the transcription factor, BHLHE40, to be highly expressed in Tr1 cells. Even though Tr1 cells characteristically produce high levels of IL-10, we found that BHLHE40 represses IL-10 and increases IFN-γ secretion in naïve CD4+ T cells. Through CRISPR/Cas9-mediated knockout, we determined that IL10 significantly increased in the sgBHLHE40-edited cells and BHLHE40 is dispensable for naïve CD4+ T cells to differentiate into Tr1 cells in vitro. Interestingly, BHLHE40 overexpression induces the surface expression of CD49b and LAG3, co-expressed surface molecules attributed to Tr1 cells, but promotes IFN-γ production. Our findings uncover a novel mechanism whereby BHLHE40 acts as a regulator of IL-10 and IFN-γ in human CD4+ T cells.

Glucose Degradation Products and Peritoneal Membrane Function

2001 ◽  
Vol 21 (2) ◽  
pp. 201-207 ◽  
Author(s):  
Janusz Witowski ◽  
Thorsten O. Bender ◽  
Gerhard M. Gahl ◽  
Ulrich Frei ◽  
Achim Jörres
Keyword(s):  
Peritoneal Dialysis ◽  
Cell Viability ◽  
Degradation Products ◽  
Membrane Function ◽  
Peritoneal Mesothelial Cells ◽  
Glucose Degradation Products ◽  
And Function ◽  
The Impact ◽  
Dialysis Fluids

Background The bioincompatibility of peritoneal dialysis fluids (PDF) in current use has been partially attributed to the presence of glucose degradation products (GDPs), which are generated during heat sterilization of PDF. Several of the GDPs have been identified and we have recently demonstrated that these GDPs per se may impair the viability and function of human peritoneal mesothelial cells (HPMC) in vitro. It is also possible that GDP-related toxicity is further exacerbated by the milieu of PDF. We review the current literature on GDP and present the results of experiments comparing the impact of heat- and filter-sterilized PDF on the viability and function of HPMC. Methods Peritoneal dialysis fluids with low (1.5%) and high (4.25%) glucose concentrations were laboratory prepared according to the standard formula and sterilized either by heat (H-PDF; 121°C, 0.2 MPa, 20 minutes) or filtration (F-PDF; 0.2 μ). The buildup of GDP was confirmed by UV absorbance at 284 nm. Confluent HPMC monolayers were exposed to these solutions mixed 1:1 with standard M199 culture medium. After 24 hours, cell viability was assessed with the MTT assay, and interleukin-1β–stimulated monocyte chemotactic protein-1 (MCP-1) release with specific immunoassay. Results Exposure of HPMC to H-PDF resulted in a significant decrease in cell viability, with solutions containing 4.25% glucose being more toxic than 1.5% glucose-based PDF (27.4% ± 3.4% and 53.4% ± 11.0% of control values, respectively). In contrast, viability of HPMC exposed to F-PDF was not different from that of control cells. Moreover, treatment with H-PDF impaired the release of MCP-1 from HPMC to a significantly greater degree compared to F-PDF (17.4% and 24.9% difference for low and high glucose PDF, respectively). Conclusions Exposure of HPMC to H-PDF significantly impairs cell viability and the capacity for generating MCP-1 compared to F-PDF. This effect is likely to be mediated by GDPs present in H-PDF but not in F-PDF.

In Vitro Antagonistic Properties of a New Angiotensin Type 1 Receptor Blocker, Azilsartan, in Receptor Binding and Function Studies

2010 ◽  
Vol 336 (3) ◽  
pp. 801-808 ◽  
Author(s):  
Mami Ojima ◽  
Hideki Igata ◽  
Masayuki Tanaka ◽  
Hiroki Sakamoto ◽  
Takanobu Kuroita ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Receptor Blocker ◽  
And Function ◽  
Angiotensin Type

scholarly journals Interleukin-22 reverses human islet dysfunction and apoptosis triggered by hyperglycemia and LIGHT

2018 ◽  
Vol 60 (3) ◽  
pp. 171-183
Author(s):  
Shadab Abadpour ◽  
Bente Halvorsen ◽  
Afaf Sahraoui ◽  
Olle Korsgren ◽  
Pål Aukrust ◽  
...  
Keyword(s):  
Islet Cells ◽  
Harmful Effect ◽  
Human Islets ◽  
Protective Role ◽  
Human Islet ◽  
Islet Function ◽  
Post Transplantation ◽  
Interleukin 22 ◽  
Glucose Stimulated Insulin Secretion

Interleukin (IL)-22 has recently been suggested as an anti-inflammatory cytokine that could protect the islet cells from inflammation- and glucose-induced toxicity. We have previously shown that the tumor necrosis factor family member, LIGHT, can impair human islet function at least partly via pro-apoptotic effects. Herein, we aimed to investigate the protective role of IL-22 on human islets exposed to the combination of hyperglycemia and LIGHT. First, we found upregulation of LIGHT receptors (LTβR and HVEM) in engrafted human islets exposed to hyperglycemia (>11 mM) for 17 days post transplantation by using a double islet transplantation mouse model as well as in human islets cultured with high glucose (HG) (20 mM glucose) + LIGHT in vitro, and this latter effect was attenuated by IL-22. The effect of HG + LIGHT impairing glucose-stimulated insulin secretion was reversed by IL-22. The harmful effect of HG + LIGHT on human islet function seemed to involve enhanced endoplasmic reticulum stress evidenced by upregulation of p-IRE1α and BiP, elevated secretion of pro-inflammatory cytokines (IL-6, IL-8, IP-10 and MCP-1) and the pro-coagulant mediator tissue factor (TF) release and apoptosis in human islets, whereas all these effects were at least partly reversed by IL-22. Our findings suggest that IL-22 could counteract the harmful effects of LIGHT/hyperglycemia on human islet cells and potentially support the strong protective effect of IL-22 on impaired islet function and survival.

Biocompatibility of a Bicarbonate/Lactate-Buffered PD Fluid Tested with a Double-Chamber Cell Culture System

2005 ◽  
Vol 25 (4) ◽  
pp. 387-393 ◽  
Author(s):  
Andreas Fusshoeller ◽  
Jessica Baehr ◽  
Bernd Grabensee ◽  
Joerg Plum
Keyword(s):  
Cell Culture ◽  
Cell Viability ◽  
Culture System ◽  
Mesothelial Cell ◽  
In Vitro Studies ◽  
Cell Culture System ◽  
And Function ◽  
Tgf Β1 ◽  
Double Chamber

Objective In peritoneal dialysis (PD), neutrally buffered PD fluids with lower concentrations of glucose degradation products (GDP) have tested superior to conventional fluids in terms of biocompatibility. However, conventional in vitro studies provoke debate because, due to the lack of subsequent equilibration with the blood, they do not resemble the true intraperitoneal situation of PD. Methods We established a double-chamber cell culture system with peritoneal mesothelial cells seeded on top of a permeable membrane, with a physiological buffer below. Thus adequately reflecting the in vivo equilibration pattern, we compared a conventional fluid with a neutral bicarbonate/lactate-buffered PD solution. Using an exchange pattern adapted from an 8-hour continuous ambulatory PD regimen, cell viability was assessed with an MTT assay, and cell function via constitutive and stimulated interleukin (IL)-6 release. As an indicator of potential induction of fibrosis and as a parameter of mesothelial cell integrity, respectively, transforming growth factor-beta 1 (TGF-β1) generation and cancer antigen 125 (CA125) release were measured. Results The conventional solution significantly compromised mesothelial cell viability and function in terms of mitochondrial activity ( p < 0.05) and stimulated IL-6 release ( p < 0.05). The bicarbonate/lactate fluid had no effect on cell viability or IL-6 release and turned out to be equivalent to the properties of the growth medium. Whereas lactate-incubated cells did not respond to IL-1β stimulation, bicarbonate/lactate-treated cells adequately increased IL-6 release after stimulation ( p < 0.0005). Release of TGF-β1 and CA125 did not differ between the different fluids and the control. Conclusions Due to the sustained equilibration process, the double-chamber cell culture model allows a more realistic insight into mesothelial cell viability and function in terms of PD. As in classic in vitro studies, an adverse effect of conventional PD solutions on mesothelial cells was overt in the present cell culture system. The neutral bicarbonate/lactate-buffered fluid with low GDP content, however, did not interfere with mesothelial cell vitality or function, indicating superior biocompatibility.

scholarly journals Bacterial Outer Membrane Ushers Contain Distinct Targeting and Assembly Domains for Pilus Biogenesis

2002 ◽  
Vol 184 (22) ◽  
pp. 6260-6269 ◽  
Author(s):  
David G. Thanassi ◽  
Christos Stathopoulos ◽  
Karen Dodson ◽  
Dominik Geiger ◽  
Scott J. Hultgren
Keyword(s):  
Outer Membrane ◽  
Secretory Pathway ◽  
Terminal Branch ◽  
C Terminus ◽  
Type 1 Pili ◽  
Pilus Biogenesis ◽  
And Function

ABSTRACT Biogenesis of a superfamily of surface structures by gram-negative bacteria requires the chaperone/usher pathway, a terminal branch of the general secretory pathway. In this pathway a periplasmic chaperone works together with an outer membrane usher to direct substrate folding, assembly, and secretion to the cell surface. We analyzed the structure and function of the PapC usher required for P pilus biogenesis by uropathogenic Escherichia coli. Structural analysis indicated PapC folds as a β-barrel with short extracellular loops and extensive periplasmic domains. Several periplasmic regions were localized, including two domains containing conserved cysteine pairs. Functional analysis of deletion mutants revealed that the PapC C terminus was not required for insertion of the usher into the outer membrane or for proper folding. The usher C terminus was not necessary for interaction with chaperone-subunit complexes in vitro but was required for pilus biogenesis in vivo. Interestingly, coexpression of PapC C-terminal truncation mutants with the chromosomal fim gene cluster coding for type 1 pili allowed P pilus biogenesis in vivo. These studies suggest that chaperone-subunit complexes target an N-terminal domain of the usher and that subunit assembly into pili depends on a subsequent function provided by the usher C terminus.

scholarly journals Beta-cell function and human islet transplantation: can we improve?

2021 ◽  
Author(s):  
Jennifer Chen ◽  
Jenny E Gunton
Keyword(s):  
Islet Transplantation ◽  
Cell Function ◽  
Therapeutic Option ◽  
Human Islets ◽  
Post Transplantation ◽  
Human Islet Transplantation ◽  
And Function ◽  
Islet Survival

Islet transplantation, a therapeutic option to treat type 1 diabetes, is not yet as successful as whole-pancreas transplantation as a treatment for diabetes. Mouse models are commonly used for islet research. However, it is clear disparities exist between islet transplantation outcomes in mice and humans. Given the shortage of transplant-grade islets, it is crucial that we further our understanding of factors that determine long-term islet survival and function post-transplantation. In turn, that may lead to new therapeutic targets and strategies that to improve transplant outcomes. Here, we summarise the current landscape in clinical transplantation, highlight underlying similarities and differences between mouse and human islets, and review interventions that are being considered to create a new pool of β-cells for clinical application.

scholarly journals Optimization of An O2-Balanced Bioartificial Pancreas for Type 1 Diabetes Using Statistical Design of Experiment.

2021 ◽  
Author(s):  
Anne Mouré ◽  
Sawsen Bekir ◽  
Elodie Bacou ◽  
Karine Haurogne ◽  
Marie Allard ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Design Of Experiment ◽  
Statistical Design ◽  
Bioartificial Pancreas ◽  
Promising Alternative ◽  
Neonatal Pig ◽  
And Function ◽  
Full Factorial

Abstract A bioArtificial pancreas (BAP) encapsulating high pancreatic islets concentration is a promising alternative for type 1 diabetes. However, the main limitation of this approach is O2 supply, especially until graft neovascularization. Here, we described a methodology to design an optimal O2-balanced BAP using statistical design of experiment (DoE). A full factorial DoE was first performed to screen two O2-technologies on their ability to preserve pseudo-islet viability and function under hypoxia and normoxia. Then, response surface methodology was used to define the optimal O2-carrier and islet seeding concentrations to maximize the number of viable pseudo-islets in the BAP containing an O2-generator under hypoxia. Monitoring of viability, function and maturation of neonatal pig islets for 15 days in vitro demonstrated the efficiency of the optimal O2-balanced BAP. The findings should allow the design of a more realistic BAP for humans with high islets concentration by maintaining the O2 balance in the device.

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