Abstract: SA-PO138
Reduction of H3K27Me3 and Metabolic Memory Associated Inflammation in Podocytes
Session Information
- Diabetic and Obesity Induced Kidney Disease - Experimental
November 04, 2017 | Location: Hall H, Morial Convention Center
Abstract Time: 10:00 AM - 10:00 AM
Category: Diabetes
- 503 Diabetes Mellitus and Obesity: Translational
Authors
- Dieter, Brad, Providence Sacred Heart , Spokane, Washington, United States
- Meek, Rick L., Providence Sacred Heart , Spokane, Washington, United States
- Anderberg, Robert J., Providence Sacred Heart , Spokane, Washington, United States
- Cooney, Sheryl K., Providence Sacred Heart , Spokane, Washington, United States
- Tuttle, Katherine R., Providence Sacred Heart , Spokane, Washington, United States
Background
Poor glycemic control, even with subsequent periods of well-controlled glycemia, increases risk for diabetic complications. This phenomenon, known as metabolic memory, may cause epigenetic changes such as reduction of histone 3 lysine 27 trimethylation (H3K27Me3), which increases expression of inflammatory mediators including serum amyloid A (SAA) in the diabetic kidney. The aim of this study was to determine if a sustained inflammatory response to metabolic memory may be mediated by increased SAA expression due to H3K27Me3 demethylation near the SAA promoter in podocytes, a cell centrally involved in diabetic kidney disease.
Methods
SAA knockout podocytes were generated using CRISPR-Cas9. In experiments to model metabolic memory, wild type and SAA knockout mouse podocytes were differentiated for 8-10 days, then exposed to advanced glycation end products (AGE, 300 μg/ml) for 7 days, followed by AGE removal and ongoing culture in control conditions for 7 more days. Chromatin immunoprecipitation measured H3K27Me3 near the SAA promoter. qRT-PCR was used to measure mRNA expression of inflammatory mediators: SAA, CXCL5, CCL2, and CCL5. Podocytes were exposed to AGE (300 μg/ml) for 1 day while H3K27Me3 demethylation was prevented by inhibiting the H3K27me3 specific demethylase, jmjd3, with GSK-J1 (20 μM).
Results
In metabolic memory experiments conducted in podocytes (n=6), histone H3K27Me3 near the SAA promoter was markedly reduced (95%) at day 14, while SAA mRNA increased (17±6-fold, p=0.025), as were SAA-dependent inflammatory mediators: CXCL5 (18.5±12-fold, p=0.004), CCL2 (2.0±0.7-fold, p=0.001), and CCL5 (1.6±0.6-fold, p=0.026). SAA knockout in podocytes reduced expression of CXCL5, CCL2, and CCL5 by >60% (p<0.05 for all) in metabolic memory experiments. jmjd3 inhibition reduced AGE-induced expression of SAA and each of the SAA-dependent inflammatory mediators by >60% (p<0.05 for all) in podocytes.
Conclusion
Short term exposure of podocytes to hyperglycemia-related perturbations causes sustained H3K27Me3 demethylation and increased SAA expression, leading to a sustained SAA-dependent inflammatory response.
Funding
- Private Foundation Support