Abstract: FR-PO619
Deficient of Endothelial Function Exacerbates NLRP3-Inflammasome Activation in Podocyte of Diabetic Nephropathy
Session Information
- Diabetes Mellitus and Obesity: Basic - Experimental - II
November 03, 2017 | Location: Hall H, Morial Convention Center
Abstract Time: 10:00 AM - 10:00 AM
Category: Diabetes
- 501 Diabetes Mellitus and Obesity: Basic - Experimental
Authors
- Nagasu, Hajime, Kawasaki Medical School, Kurashiki, Japan
- Sogawa, Yuji, Kawasaki Medical School, Kurashiki, Japan
- Kidokoro, Kengo, Kawasaki Medical School, Kurashiki, Japan
- Satoh, Minoru, Kawasaki Medical School, Kurashiki, Japan
- Sasaki, Tamaki, Kawasaki Medical School, Kurashiki, Japan
- Kashihara, Naoki, Kawasaki Medical School, Kurashiki, Japan
Background
Previous studies have indicated that 30–40% of patients with type 1 DM develop overt nephropathy, but the detailed mechanism is not clear.
Reactive oxygen species (ROS) are excessively produced in DM, and ROS production exacerbates nephropathy. We reported that the uncoupling of endothelial nitric oxide (NO) synthase (eNOS) is the source of glomerular ROS production. While NLRP3 inflammasome activation in podocytes plays an important role in the progression of DKD, whereas NO regulates inflammasome activation. However, it is unclear how the NLRP3 inflammasome is regulated in the kidney.
In this study, we determined if eNOS/NO signaling suppresses inflammasome activation in DKD.
Methods
We used wild-type (WT) and eNOS-deficient mice (eNOSKO) to determine the role of the eNOS-NO pathway.
Diabetes was induced by a single intraperitoneal injection of streptozocin (STZ; 65 mg/kg body weight).
Subsequently, we divided mice into four groups: WT, WT-STZ, eNOSKO, and eNOS-STZ. Four weeks after the induction of DM, the mice were sacrificed, and their kidney tissues were harvested. Urinary albumin excretion was checked before the sacrifice, and glomerular damage was assessed by PAS staining. Next, the localization of inflammasome activation in glomeruli was evaluated with immunohistochemical analyses.
To investigate inflammasome activation in glomeruli, glomeruli were isolated from the kidney tissue by using Dynabeads. The mRNA expression of inflammasome components NLRP3, IL-1β, and IL-18 were checked with real-time quantitative PCR.
Results
Urinary albumin excretion was increased in WT-STZ compared with WT. These urinary albumin excretions were increased much more in eNOS-STZ than in WT-STZ. The glomeruli were more damaged in eNOS-STZ compared with WT-STZ.
In immunohistochemical analyses, the expression of ASC coexisted with podocytes detected by podocalyxin staining in eNOS-STZ. These data suggested that the NLRP3 inflammasome activation was located in podocytes. In isolated glomeruli, the mRNA of the inflammasome components were higher in eNOS-STZ than in WT-STZ.
Conclusion
eNOS/NO signaling attenuates glomerular injury in diabetic mice via suppression of inflammasome activation.
Funding
- Private Foundation Support