Abstract
Background and aims: Diabetes is the leading cause of end stage kidney failure. Oxidative stress due to excessive production of reactive oxygen species plays a critical role in diabetic kidney disease (DKD). Pro-oxidant enzyme NADPH oxidase-NOX5 is considered as a major contributor of ROS and thereby aggravating renal injury in DKD. We aim to identify the pathogenic role of NOX5 and associated ROS-sensitive pathways in DKD using various experimental models including human kidney biopsies, human renal organoids and cells, humanised NOX5 transgenic mice and rabbit models as well as novel NOX5-specific inhibitors.
Materials and methods: We examined the ROS production as well as expression of NOX5 in association with ROS-sensitive factors including a protein kinase, PKC-α, a transcription factor, EGR1 (early growth response 1) and a key metabolic gene involved in redox balance, TXNIP (thioredoxin-interacting protein) in human kidney biopsies, human renal organoids and cells. We assessed the effect of NOX5 inhibition using genetic manipulation and pharmacological inhibition approaches in human renal cells and organoids exposed to diabetic milieu environment. In vivo, we also assessed the effect of endothelial cell specific -Nox5 overexpression independent of NOX4 in humanised Nox5 transgenic mice in the presence or absence of streptozotocin induced diabetes.
Results: We identified increased expression of renal NOX5 in diabetic patients and in high fat fed rabbits. We also found a positive association of renal NOX5 with upregulation of EGR-1, PKC-α and TXNIP. In vivo, overexpression of human NOX5 independent of NOX4 pathways demonstrated an increase in albuminuria, glomerulosclerosis, renal fibrosis and inflammation in association with upregulation of EGR-1, ERK1/2, PKC-α, PKC-ε and TXNIP via enhanced ROS production in comparison to diabetic mice not expressing Nox5. In vitro, pharmacological inhibition of Nox5 attenuated high glucose induced gene expression of markers of fibrosis and inflammation as well as downregulation of EGR-1, PKC-α and TXNIP.
Conclusion: The findings of this study suggest that NOX5 plays a key role in human DKD, thereby providing the impetus for the fast track validation of NOX5 specific inhibitors to improve kidney health in diabetes.
Materials and methods: We examined the ROS production as well as expression of NOX5 in association with ROS-sensitive factors including a protein kinase, PKC-α, a transcription factor, EGR1 (early growth response 1) and a key metabolic gene involved in redox balance, TXNIP (thioredoxin-interacting protein) in human kidney biopsies, human renal organoids and cells. We assessed the effect of NOX5 inhibition using genetic manipulation and pharmacological inhibition approaches in human renal cells and organoids exposed to diabetic milieu environment. In vivo, we also assessed the effect of endothelial cell specific -Nox5 overexpression independent of NOX4 in humanised Nox5 transgenic mice in the presence or absence of streptozotocin induced diabetes.
Results: We identified increased expression of renal NOX5 in diabetic patients and in high fat fed rabbits. We also found a positive association of renal NOX5 with upregulation of EGR-1, PKC-α and TXNIP. In vivo, overexpression of human NOX5 independent of NOX4 pathways demonstrated an increase in albuminuria, glomerulosclerosis, renal fibrosis and inflammation in association with upregulation of EGR-1, ERK1/2, PKC-α, PKC-ε and TXNIP via enhanced ROS production in comparison to diabetic mice not expressing Nox5. In vitro, pharmacological inhibition of Nox5 attenuated high glucose induced gene expression of markers of fibrosis and inflammation as well as downregulation of EGR-1, PKC-α and TXNIP.
Conclusion: The findings of this study suggest that NOX5 plays a key role in human DKD, thereby providing the impetus for the fast track validation of NOX5 specific inhibitors to improve kidney health in diabetes.
| Original language | English |
|---|---|
| Article number | 132 |
| Pages (from-to) | S71 |
| Number of pages | 1 |
| Journal | Diabetologia |
| Volume | 66 |
| Issue number | Suppl 1 |
| DOIs | |
| Publication status | Published - Sept 2023 |
| Event | Annual Meeting of the European-Association-for-the- Study-of-Diabetes (EASD) 2023 - , Germany Duration: 2 Oct 2023 → 6 Oct 2023 Conference number: 59th https://link.springer.com/article/10.1007/s00125-023-05969-6 |
