Related Experiment Video
Updated: Jun 2, 2025
A High-content In Vitro Pancreatic Islet β-cell Replication Discovery Platform
Published on: July 16, 2016
DOC2b enrichment mitigates proinflammatory cytokine-induced CXCL10 expression by attenuating IKKβ and STAT-1
Diti Chatterjee Bhowmick1, Miwon Ahn1, Supriyo Bhattacharya2
1Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute of City of Hope, Duarte, CA, USA.
Introduction:
Type 1 diabetic human islet β-cells are deficient in double C 2 like domain beta (DOC2b) protein. Further, DOC2b protects against cytokine-induced pancreatic islet β-cell stress and apoptosis. However, the mechanisms underpinning the protective effects of DOC2b remain unknown.
Methods:
Biochemical studies, qPCR, proteomics, and immuno-confocal microscopy were conducted to determine the underlying protective mechanisms of DOC2b in β-cells. DOC2b-enriched or -depleted primary islets (human and mouse) and β-cell lines challenged with or without proinflammatory cytokines, global DOC2b heterozygous knockout mice subjected to multiple-low-dose-streptozotocin (MLD-STZ), were used for these studies.
Results:
A significant elevation of stress-induced CXCL10 mRNA was observed in DOC2b-depleted β-cells and primary mouse islets. Further, DOC2b enrichment markedly attenuated cytokine-induced CXCL10 levels in primary non-diabetic human islets and β-cells. DOC2b enrichment also reduced total-NF-κB p65 protein levels in human islets challenged with T1D mimicking proinflammatory cytokines. IKKβ, NF-κB p65, and STAT-1 are capable of associating with DOC2b in cytokine-challenged β-cells. DOC2b enrichment in cytokine-stressed human islets and β-cells corresponded with a significant reduction in activated and total IKKβ protein levels. Total IκBβ protein was increased in DOC2b-enriched human islets subjected to acute cytokine challenge. Cytokine-induced activated and total STAT-1 protein and mRNA levels were markedly reduced in DOC2b-enriched human islets. Intriguingly, DOC2b also prevents ER-stress-IKKβ and STAT-1 crosstalk in the rat INS1-832/13 β-cell line.
Conclusion:
The mechanisms underpinning the protective effects of DOC2b involve attenuation of IKKβ-NF-κB p65 and STAT-1 signaling, and reduced CXCL10 expression.
Insights
Double C 2 like domain beta (DOC2b) protein deficiency in type 1 diabetes impairs pancreatic islet beta-cells. DOC2b protects these cells by reducing inflammation and stress signaling pathways.
Area of Science:
- Endocrinology
- Cell Biology
- Immunology
Background:
- Type 1 diabetic human islet beta-cells exhibit reduced double C 2 like domain beta (DOC2b) protein.
- DOC2b plays a protective role against cytokine-induced stress and apoptosis in pancreatic islet beta-cells.
- The precise mechanisms of DOC2b's protective action remain largely unelucidated.
Purpose of the Study:
- To investigate the underlying molecular mechanisms by which DOC2b exerts its protective effects in beta-cells.
- To determine DOC2b's role in regulating inflammatory signaling pathways and stress responses in pancreatic islets.
Main Methods:
- Utilized biochemical assays, qPCR, proteomics, and immuno-confocal microscopy.
- Employed DOC2b-enriched or -depleted primary human and mouse islets and beta-cell lines.
- Studied global DOC2b heterozygous knockout mice subjected to multiple low-dose streptozotocin (MLD-STZ) and cytokine challenges.
Main Results:
- DOC2b depletion increased stress-induced CXCL10 mRNA in beta-cells and islets.
- DOC2b enrichment reduced cytokine-induced CXCL10, NF-κB p65, activated IKKβ, and STAT-1 levels.
- DOC2b was found to associate with IKKβ, NF-κB p65, and STAT-1, and prevented ER-stress-IKKβ and STAT-1 crosstalk.
Conclusions:
- DOC2b's protective effects stem from attenuating IKKβ-NF-κB p65 and STAT-1 signaling pathways.
- Reduced CXCL10 expression is a key outcome of DOC2b's protective action.
- DOC2b safeguards pancreatic beta-cells from inflammatory and stress-induced damage.
Related Concept Videos
01:20The JAK-STAT Signaling Pathway
01:58Cell Specific Gene Expression