Back to Search
Start Over
Insulin increases surface expression of TRPC6 channels in podocytes: role of NADPH oxidases and reactive oxygen species
- Source :
- American Journal of Physiology-Renal Physiology. 302:F298-F307
- Publication Year :
- 2012
- Publisher :
- American Physiological Society, 2012.
-
Abstract
- Insulin receptors in podocytes are essential for normal kidney function. Here, we show that insulin evokes a rapid increase in the surface expression of canonical transient receptor potential-6 channel (TRPC6) channels in cultured podocytes, but caused a decrease in surface expression of TRPC5. These effects are accompanied by a marked increase in outwardly rectifying cationic currents that can be blocked by 10 μM SKF96365 or 100 μM La3+. Application of oleoyl-2-acetyl- sn-glycerol (OAG) also increased SKF96365- and La3+-sensitive cationic currents in podocytes. Importantly, current responses to a combination of OAG and insulin were the same amplitude as those evoked by either agent applied alone. This occlusion effect suggests that OAG and insulin are targeting the same population of channels. In addition, shRNA knockdown of TRPC6 markedly reduced cationic currents stimulated by insulin. The effects of insulin on TRPC6 were mimicked by treating podocytes with H2O2. Insulin treatment rapidly increased the generation of H2O2 in podocytes, and it increased the surface expression of the NADPH oxidase NOX4 in cultured podocytes. Basal and insulin-stimulated surface expression of TRPC6 were reduced by pretreatment with diphenylene iodonium, an inhibitor of NADPH oxidases and other flavin-dependent enzymes, by siRNA knockdown of NOX4, and by manganese (III) tetrakis (4-benzoic acid) porphyrin chloride, a membrane-permeable mimetic of superoxide dismutase and catalase. These observations suggest that insulin increases generation of ROS in part through activation of NADPH oxidases, and that this step contributes to modulation of podocyte TRPC6 channels.
- Subjects :
- Patch-Clamp Techniques
Metalloporphyrins
Physiology
medicine.medical_treatment
Cell Line
Membrane Potentials
TRPC6
Mice
Cations
TRPC6 Cation Channel
medicine
Animals
Hypoglycemic Agents
Insulin
Patch clamp
RNA, Small Interfering
Receptor
TRPC Cation Channels
chemistry.chemical_classification
Reactive oxygen species
biology
Glomerulosclerosis, Focal Segmental
Podocytes
Imidazoles
NADPH Oxidases
Free Radical Scavengers
Hydrogen Peroxide
Calcium Channel Blockers
Cell biology
Insulin receptor
chemistry
Biochemistry
NADPH Oxidase 4
Cell culture
Call for Papers
biology.protein
Reactive Oxygen Species
Subjects
Details
- ISSN :
- 15221466 and 1931857X
- Volume :
- 302
- Database :
- OpenAIRE
- Journal :
- American Journal of Physiology-Renal Physiology
- Accession number :
- edsair.doi.dedup.....bf9cb0765ba7fca5aebe32d7ca9c5f77