Implication of Mitochondrial Cytoprotection in Human Islet Isolation and Transplantation

Wang, Yong; Mendoza-Elias, Joshua E.; Qi, Meirigeng; Harvat, Tricia A.; Ahn, Sang Joon; Lee, Dongyoung; Gutiérrez, Diana; Jeon, Hae Jeong; Paushter, Daniel H.; Oberholzer, José

doi:10.1155/2012/395974

Cited by 6 publications

(6 citation statements)

References 163 publications

(148 reference statements)

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“…Chronic hypoxia has been shown to increase signaling through multiple pathways including the RhoA/ROCK pathway [64], [65]. It is probable that the hypoxic conditions associated with the isolation of human islets from cadaveric donors and their shipment upregulates RhoA/ROCK signaling [19], [66].…”

Section: Discussionmentioning

confidence: 99%

A Novel Strategy to Increase the Proliferative Potential of Adult Human β-Cells While Maintaining Their Differentiated Phenotype

et al. 2013

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Our previous studies demonstrated that Wnt/GSK-3/β-catenin and mTOR signaling are necessary to stimulate proliferative processes in adult human β-cells. Direct inhibition of GSK-3, that engages Wnt signaling downstream of the Wnt receptor, increases β-catenin nuclear translocation and β-cell proliferation but results in lower insulin content. Our current goal was to engage canonical and non-canonical Wnt signaling at the receptor level to significantly increase human β-cell proliferation while maintaining a β-cell phenotype in intact islets. We adopted a system that utilized conditioned medium from L cells that expressed Wnt3a, R-spondin-3 and Noggin (L-WRN conditioned medium). In addition we used a ROCK inhibitor (Y-27632) and SB-431542 (that results in RhoA inhibition) in these cultures. Treatment of intact human islets with L-WRN conditioned medium plus inhibitors significantly increased DNA synthesis ∼6 fold in a rapamycin-sensitive manner. Moreover, this treatment strikingly increased human β-cell proliferation ∼20 fold above glucose alone. Only the combination of L-WRN conditioned medium with RhoA/ROCK inhibitors resulted in substantial proliferation. Transcriptome-wide gene expression profiling demonstrated that L-WRN medium provoked robust changes in several signaling families, including enhanced β-catenin-mediated and β-cell-specific gene expression. This treatment also increased expression of Nr4a2 and Irs2 and resulted in phosphorylation of Akt. Importantly, glucose-stimulated insulin secretion and content were not downregulated by L-WRN medium treatment. Our data demonstrate that engaging Wnt signaling at the receptor level by this method leads to necessary crosstalk between multiple signaling pathways including activation of Akt, mTOR, Wnt/β-catenin, PKA/CREB, and inhibition of RhoA/ROCK that substantially increase human β-cell proliferation while maintaining the β-cell phenotype.

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Section: Discussionmentioning

confidence: 99%

A Novel Strategy to Increase the Proliferative Potential of Adult Human β-Cells While Maintaining Their Differentiated Phenotype

et al. 2013

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“…The induced error in both surface tension and pressure jump is a quadratic function of interface thickness times curvature, the coefficient of this error being small [26]. Equations (4) and (5) are coupled with the Navier-Stokes equations (1). There, density and viscosity depend on the order parameter, similar to Eq.…”

Section: Phase-field Methodsmentioning

confidence: 99%

“…Using droplets as micro reaction chambers in the medical and biochemical field is one key application [2,3]. While such droplets are purposely produced, the undesired emergence of gas bubbles is a common problem severely impairing the functionality of microfluidic devices [4]. Adverse effects range from larger bubbles clogging channels [5,6] to smaller bubbles pinning to channel walls disturbing the flow.…”

Section: Introductionmentioning

confidence: 99%

On suitability of phase-field and algebraic volume-of-fluid OpenFOAM® solvers for gas–liquid microfluidic applications

Jamshidi

Heimel

Hasert

et al. 2019

Computer Physics Communications

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Microfluidic devices often contain several phases. Their design can be supported by interface-resolving numerical simulations, requiring accurate methods and validated computer codes. Especially challenging are submillimetre air bubbles in water due to their large density contrast and dominance of surface tension. Here, we evaluate two numerical methods implemented in OpenFOAM ® , namely the standard solver interFoam with an algebraic volume-of-fluid method relying on a sharp interface representation and phaseFieldFoam relying on the phase-field method with diffuse interface representation. For a circular bubble in static equilibrium, we explore the impacts of uniform grid resolution and bubble size on bubble shape, mass conservation, pressure jump and spurious currents. While the standard interFoam solver exhibits excellent mass conservation with errors below 0.1% on fine grids, it lacks the accuracy to predict reasonable physics for a bubble in microfluidic systems. At higher resolution, large spurious currents significantly displace and deform the bubble, which is oscillating with resolution dependent mode and frequency. Furthermore, the pressure jump is consistently underestimated by more than 10%. The solver phaseFieldFoam suffers from much larger mass losses of up to 2%, which decrease as the ratio between interface thickness and bubble diameter decreases provided the diffuse interface region is adequately resolved. Spurious currents are very low and the bubble remains circular preserving its initial position with an error in pressure jump below 1%.

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“…Mitochondrial metabolism is also regulated by mTORc1; thus, SIR is competent to interfere with the mitochondrial function [21]. In T lymphocytes, SIR has been shown to prompt the disruption of mitochondrial membrane integrity and to lower oxygen consumption and ATP levels [22].…”

Section: Abbreviations Dwmmentioning

confidence: 99%

Differential influence of tacrolimus and sirolimus on mitochondrial-dependent signaling for apoptosis in pancreatic cells

et al. 2016

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To examine and compare the mitochondria-related cellular mechanisms by which tacrolimus (TAC) or sirolimus (SIR) immunosuppressive drugs alter the pancreatic exocrine and endocrine β-cell fate. Human exocrine PANC-1 and rat endocrine insulin-secreting RIN-m5F cells and isolated rat islets were submitted to 1-100 nM TAC or SIR. In cultures, insulin secretion was measured as endocrine cell function marker. Apoptosis was quantified by annexin 5 and propidium iodide staining. Cleaved caspase-3, Bax apoptosis indicators, and p53, p21 cell cycle regulators were detected by Western blot. Cell cycle and mitochondrial membrane potential (ΔΨm) were analyzed by flow cytometry and SA-beta-galactosidase (SA-β-gal) activity by fluorescence microscopy. Only TAC reduced insulin secretion by RIN-m5F after 24 h. TAC and SIR promoted moderate apoptosis in both PANC-1 and RIN-m5F after 24 h. Apoptosis was associated with up-regulated Bax (threefold) and cleaved caspase-3 (fivefold) but only in PANC-1, while p53 and p21 were up-regulated (twofold) in both cell lines. ΔΨm was impaired only in PANC-1 by TAC and SIR. Only SIR prompted cell cycle arrest in both cell lines. The induction of a premature senescence-like phenotype was confirmed in isolated islets by SA-β-gal activity. TAC and SIR are early inducers of pancreatic cell dysfunction and apoptosis but differentially alter endocrine and exocrine cells via mitochondrial-driven pathways. In rat islets, TAC and SIR prompt a senescence-like phenotype.

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Implication of Mitochondrial Cytoprotection in Human Islet Isolation and Transplantation

Cited by 6 publications

References 163 publications

A Novel Strategy to Increase the Proliferative Potential of Adult Human β-Cells While Maintaining Their Differentiated Phenotype

A Novel Strategy to Increase the Proliferative Potential of Adult Human β-Cells While Maintaining Their Differentiated Phenotype

On suitability of phase-field and algebraic volume-of-fluid OpenFOAM® solvers for gas–liquid microfluidic applications

Differential influence of tacrolimus and sirolimus on mitochondrial-dependent signaling for apoptosis in pancreatic cells

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