Hydrogen peroxide permeability of cellular membranes in insulin-producing cells

• Published in: Biochimica et biophysica acta. Biomembranes 2020-02, Vol.1862 (2), p.183096-183096, Article 183096
• Main Authors: Laporte, Anna, Lortz, Stephan, Schaal, Christina, Lenzen, Sigurd, Elsner, Matthias
• Format: Article
• Language: English
• Subjects: Beta-cells; Biosensing Techniques; Cell Membrane - metabolism; Diffusion; Free fatty acids; Genetically encoded sensors; Humans; Hydrogen peroxide; Hydrogen Peroxide - metabolism; Insulin-Secreting Cells - metabolism; Insulin-Secreting Cells - ultrastructure; Kinetics; Membrane permeability; Oxidation-Reduction; Oxidative Stress; Permeability
• ISSN: 0005-2736; 1879-2642
• DOI: 10.1016/j.bbamem.2019.183096

Hydrogen peroxide (H2O2) plays a central role in redox signalling and in oxidative stress-mediated cell death. It is generated through multiple mechanisms at various intracellular sites. Due to its chemical stability it can reach distant sites of action. However, its hydrophilicity can hamper lipid membrane passage. We therefore studied the kinetics of H2O2 diffusion through subcellular membranes employing the H2O2 biosensor HyPer in insulin-producing RINm5F cells. Plasma- and ER-membrane-bound HyPer sensors facing the cytosolic compartment reacted twice as fast to H2O2 compared to sensors expressed in peroxisomes and mitochondria. Overexpression of the H2O2-inactivating enzyme catalase in the ER-lumen and in the peroxisomes retarded the reaction time of HyPer, both localised within the peroxisomes as well as at the cytosolic surface of the ER. The unsaturated fatty acid oleic acid did not affect the reaction of the peroxisomal HyPer sensor to H2O2, while the saturated fatty acid palmitic acid accelerated its reaction time to H2O2 in this organelle. The results show that the plasma-, peroxisomal, and mitochondrial membrane of insulin-producing RINm5F cells are permeable for H2O2. Nonetheless, the organelle membranes retard H2O2 diffusion due to a barrier function of the lipid membrane, as documented by retarded reaction times of the intraorganellar sensors. Accelerated decomposition of H2O2 by catalase, expressed in the peroxisomes or the ER, further retarded the HyPer sensor reaction time. The results show that redox signalling and oxidative stress-mediated toxicity are crucially dependent on physicochemical membrane properties and antioxidative defence mechanisms in health and disease. [Display omitted] •H2O2 can travel within compartments of insulin-producing cells.•Membranes of the cell and organelles represent a diffusion barrier for H2O2.•Accelerated decomposition of H2O2 by catalase retards HyPer sensor reaction to H2O2.•Incorporation of PA into the peroxisomal membrane makes it more permeable for H2O2.