A High-Content Screen for the Identification of Plant Extracts with Insulin Secretion-Modulating Activity

Hager, Roland; Pitsch, Johannes; Kerbl-Knapp, Jakob; Neuhauser, Cathrina; Ollinger, Nicole; Iken, Marcus; Ranner, Josef; Mittermeier-Kleßinger, Verena Karolin; Dawid, Corinna; Lanzerstorfer, Peter; Weghuber, Julian

doi:10.3390/ph14080809

Cited by 15 publications

(10 citation statements)

References 65 publications

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Section: Antihyperglycemic Activitymentioning

confidence: 99%

“…After being released from cells, insulin can be measured via radioimmunoassay [85,86] or ELISA. Recently, a luminescent alternative to detect insulin was described by Hager et al and Kalwat et al [87,88]. Despite continuous improvements in measuring glucose and glucose-associated processes, a relevant challenge is to fully understand the physiological and pathological roles of blood glucose levels and their impact on health conditions and disease.…”

Section: Antihyperglycemic Activitymentioning

confidence: 99%

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Evaluation of Biological Activity of Natural Compounds: Current Trends and Methods

et al. 2022

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Natural compounds have diverse structures and are present in different forms of life. Metabolites such as tannins, anthocyanins, and alkaloids, among others, serve as a defense mechanism in live organisms and are undoubtedly compounds of interest for the food, cosmetic, and pharmaceutical industries. Plants, bacteria, and insects represent sources of biomolecules with diverse activities, which are in many cases poorly studied. To use these molecules for different applications, it is essential to know their structure, concentrations, and biological activity potential. In vitro techniques that evaluate the biological activity of the molecules of interest have been developed since the 1950s. Currently, different methodologies have emerged to overcome some of the limitations of these traditional techniques, mainly via reductions in time and costs. These emerging technologies continue to appear due to the urgent need to expand the analysis capacity of a growing number of reported biomolecules. This review presents an updated summary of the conventional and relevant methods to evaluate the natural compounds’ biological activity in vitro.

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Section: Antihyperglycemic Activitymentioning

confidence: 99%

Section: Antihyperglycemic Activitymentioning

confidence: 99%

Evaluation of Biological Activity of Natural Compounds: Current Trends and Methods

et al. 2022

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“…Insulin secretion was measured by luminescence as described. [37] GLUT4 Cell Surface Localization: GLUT4 cell surface localization was measured by total internal reflection fluorescence (TIRF) microscopy allowing for selective excitation of membrane-adjacent fluorescently tagged GLUT4 as previously described. [38] Briefly, HeLa GLUT4-myc-GFP cells were grown in RPMI 1640 in 96-well imaging plates (4 × 10 4 cells per well) overnight.…”

Section: Methodsmentioning

confidence: 99%

Anti‐Hyperglycemic Effects of Oils and Extracts Derived from Sea Buckthorn – A Comprehensive Analysis Utilizing In Vitro and In Vivo Models

Ollinger¹,

Neuhauser

Schwarzinger

et al. 2022

Molecular Nutrition Food Res

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Scope Sea buckthorn (Hippophaes rhamnoides) is capable of ameliorating disturbed glucose metabolism in animal models and human subjects. Here, the effect of sea buckthorn oil as well as of extracts of fruits, leaves, and press cake on postprandial glucose metabolism is systematically investigated. Methods and results Sea buckthorn did neither exert decisive effects in an in vitro model of intestinal glucose absorption nor did it alter insulin secretion. However, sea buckthorn stimulates GLUT4 translocation to the plasma membrane comparable to insulin, indicative of increased glucose clearance from the circulation. Isorhamnetin is identified in all sea buckthorn samples investigated and is biologically active in triggering GLUT4 cell surface localization. Consistently, sea buckthorn products lower circulating glucose by ≈10% in a chick embryo model. Moreover, sea buckthorn products fully revert hyperglycemia in the nematode Caenorhabditis elegans while they are ineffective in Drosophila melanogaster under euglycemic conditions. Conclusion These data indicate that edible sea buckthorn products as well as by‐products are promising resources for hypoglycemic nutrient supplements that increase cellular glucose clearance into target tissues.

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“…Secreted GLuc activity in this manner has been well-established as a proxy for insulin release [19,[25][26][27][28][29]. Our approach involved treating InsGLuc-MIN6 beta cells for 24 h with compounds followed by a brief wash-out prior to testing their sustained impact on insulin secretion.…”

Section: High-throughput Screen Identifies Small Molecule Modulator O...mentioning

confidence: 99%

Small molecule-mediated insulin hypersecretion induces transient unfolded protein response and loss of function in pancreatic islet beta cells

Rodrigues-dos-Santos

Roy

Binns

et al. 2022

Preprint

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Aims/hypothesisInsulin production and its regulated exocytosis by pancreatic islet beta cells is the major physiological mechanism controlling blood glucose concentrations. Beta cells are susceptible to failure due to genetic and environmental influences, leading to type 1 and 2 diabetes. In this work we aimed to advance understanding of the regulation of beta-cell function by identifying small molecule modulators of secretion.MethodsFor high-throughput screening and routine medium-throughput beta cell function assays we used mouse MIN6 beta cells stably expressing a Gaussia luciferase-linked insulin secretion reporter (InsGLuc-MIN6). We validated hit small molecules using cadaveric human islets in static culture insulin secretion assays. We measured effects on calcium influx and cAMP in MIN6 cells using Fura-2 and a bioluminescence resonance energy transfer reporter assay, respectively. Metabolism was analyzed by targeted metabolomics and Seahorse oxygen consumption assays. We measured relative gene expression and protein amounts by quantitative RT-PCR and SDS-PAGE immunoblotting, respectively.ResultsThrough our high-throughput screen we discovered 2-(3-benzyl-2-iminobenzimidazol-1-yl)-1-thiophen-2-ylethanol (SW016789) which acutely potentiated nutrient-induced calcium influx and insulin secretion. More than 2 hours of exposure to SW016789 transiently induced the unfolded protein response of the endoplasmic reticulum and shut down of insulin secretory function. Distinct from the effects of thapsigargin, SW016789 did not affect beta cell viability or death as determined by multiplexed cytotoxicity assays and a lack of induction of cleaved PARP. This may be due in part to a more rapid induction of Hspa5, and a lesser induction of signalling through the eIF2α kinase PERK and lack of expression of oxidative stress genes like Txnip. We determined that SW016789 acted upstream of the voltage-dependent calcium channel (VDCC) and potentiated nutrient-stimulated, but not KCl-stimulated, calcium influx. The potentiating effects of SW016789 were not due to altered metabolic pathways, mitochondrial function, or actions on G protein-coupled receptors. In chemical co-treatment experiments we discovered synergy between SW016789 and small molecule activators of protein kinase C and VDCCs, suggesting potential involvement of these pathways in the mechanism of action. Finally, chronically elevated calcium influx was required for the inhibitory impact of SW016789, as co-treatment with dihydropyridine-class VDCC inhibitors protected MIN6 beta cells and human islets from loss of function.Conclusions/interpretationThese data suggest the major mechanism of action of SW016789 in beta cells is to potentiate opening of VDCCs. This activity may partially depend on protein kinase C. Beta cells under pharmacological hypersecretory conditions have the capacity to suppress their function to mitigate ER stress and avoid apoptosis. Further study of the mechanisms underlying these processes will increase understanding of beta cell function in normal and pathophysiological states.Research in contextWhat is already known about this subject? Pharmacologic and environmental chemicals can stimulate aberrant beta cell activity.Hypersecretion of insulin from pancreatic beta cells can cause ER stress and lead to beta cell dysfunction.Defects in beta cell ER stress handling contribute to diabetes pathogenesis.What is the key question? Can the chemical tool SW016789 help uncover novel insulin secretion regulatory pathways and ER proteostasis factors?What are the new findings? SW016789 caused hypersecretion of insulin via enhanced nutrient-stimulated Ca2+ influx followed by transient ER stress and shutdown of beta cell function without apoptosis.Blockade of voltage-dependent Ca2+ channels protected human islets and beta cells from hypersecretion-induced dysfunction.How might this impact on clinical practice in the foreseeable future? These results have the potential to uncover beta cell ER stress mitigation factors and add support to beta cell rest strategies to preserve function.

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A High-Content Screen for the Identification of Plant Extracts with Insulin Secretion-Modulating Activity

Cited by 15 publications

References 65 publications

Evaluation of Biological Activity of Natural Compounds: Current Trends and Methods

Evaluation of Biological Activity of Natural Compounds: Current Trends and Methods

Anti‐Hyperglycemic Effects of Oils and Extracts Derived from Sea Buckthorn – A Comprehensive Analysis Utilizing In Vitro and In Vivo Models

Small molecule-mediated insulin hypersecretion induces transient unfolded protein response and loss of function in pancreatic islet beta cells

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