TY - JOUR

T1 - Hydrogen peroxide permeability of cellular membranes in insulin-producing cells

AU - Laporte, Anna

AU - Lortz, Stephan

AU - Schaal, Christina

AU - Lenzen, Sigurd

AU - Elsner, Matthias

N1 - Funding Information: We are grateful to Maren Böger, Britta Leß and Martin Wirth for their skilful technical assistance. This work was supported by Deutsche Forschungsgemeinschaft , GRK 1947/1 .

PY - 2020/2/1

Y1 - 2020/2/1

N2 - 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.

AB - 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.

KW - Biosensing Techniques

KW - Cell Membrane/metabolism

KW - Diffusion

KW - Humans

KW - Hydrogen Peroxide/metabolism

KW - Insulin-Secreting Cells/metabolism

KW - Kinetics

KW - Oxidation-Reduction

KW - Oxidative Stress

KW - Permeability

KW - Oxidative stress

KW - Hydrogen peroxide

KW - Membrane permeability

KW - Free fatty acids

KW - Beta-cells

KW - Genetically encoded sensors

UR - http://www.scopus.com/inward/record.url?scp=85075334608&partnerID=8YFLogxK

U2 - 10.1016/j.bbamem.2019.183096

DO - 10.1016/j.bbamem.2019.183096

M3 - Article

C2 - 31672544

VL - 1862

JO - Biochimica et biophysica acta: Biomembranes

JF - Biochimica et biophysica acta: Biomembranes

SN - 0005-2736

IS - 2

M1 - 183096

ER -