Abstract: FR-PO294
Esm-1 Prevents Glycocalyx Depletion in Glomerular Endothelial Cells in Diabetic Nephropathy
Session Information
- Diabetic Kidney Disease: Basic - 1
October 25, 2024 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Diabetic Kidney Disease
- 701 Diabetic Kidney Disease: Basic
Authors
- Guan, Haochen, Stanford University School of Medicine, Stanford, California, United States
- Gaudet, Alexandre, Stanford University School of Medicine, Stanford, California, United States
- Zheng, Xiaoyi, Stanford University School of Medicine, Stanford, California, United States
- Bhalla, Vivek, Stanford University School of Medicine, Stanford, California, United States
Background
Glomerular endothelial cell (GEnC) injury is one of the early characteristic signs of diabetic nephropathy (DN). Thus, markers or mediators of GEnC injury may be important to predict or prevent kidney disease, respectively. The GEnC glycocalyx forms the first part of the glomerular filtration barrier and its damage is a key initiator of albuminuria. Endothelial cell-specific molecule-1, Esm-1, is an anti-inflammatory, secreted proteoglycan. Plasma Esm-1 deficiency inversely correlates with markers of DN in humans and mice, and over-expression of Esm-1 in diabetic mice attenuates albuminuria and podocyte injury. However, it is still unclear whether and how Esm-1 modulates GEnC function in DN.
Methods
DN-susceptible DBA/2 mice were subjected to intraperitoneal injections of streptozotocin and fed a high-fat diet, and randomly assigned to receive hydrodynamic injection to overexpress Esm-1. Glycocalyx abundance was quantitated by WGA lectin staining. In vitro, human, conditionally immortalized GEnCs were maintained in the presence of glucose, insulin, TNF-α, and IL-6 to mimic a diabetic milieu. We also utilized glomerular RNAseq to characterize effects of Esm-1 expression on GEnC-expressed genes from DN-susceptible mice.
Results
Glycocalyx abundance was reduced following exposure to diabetic conditions both in vivo and in vitro. Systemic Esm-1 overexpression limited the reduction in WGA lectin glycocalyx staining in DN-susceptible mice (mean fluorescence intensity of Control vs. DM vs. DM+Esm-1, 101.9±3.643 vs. 61.47±2.786 vs.101.1±3.814; p<0.0001). Additional studies of GEnC phenotypes in vitro are ongoing. In 234 of 300 endothelial-enriched genes, we observe inverse correlations between glomerular Esm-1 mRNA expression and albuminuria (κ=0.53; p=2.29*10-29). For 206 of these 234 correlation genes, systemic over-expression of Esm-1 reverses the expression profile (κ=0.25; p=3.4*10-6), with ‘vascular development’ and ‘blood vessel morphogenesis’ being the dominant ontologies among reversible genes.
Conclusion
Our findings indicate that Esm-1 exerts a protective effect against DM-induced GEnC glycocalyx depletion. These data provide a more detailed explanation for potential mechanisms of protection from diabetes-induced albuminuria through significant changes in gene expression across GEnC.