Abstract: SA-PO570
Persistent Mechano-Growth Factor (MGF) Upregulation in Glomeruli of Diabetic or MGF-Transgenic Mice Induces Mesangial Cell (MC) Glucose Transport, PKC Activation, and Extracellular Matrix Production
Session Information
- Glomerular Diseases: Fibrosis, Extracellular Matrix
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1201 Glomerular Diseases: Fibrosis and Extracellular Matrix
Authors
- Gao, Yongxin, University of Florida, Jacksonville, Florida, United States
- Li, Hongwei, Southern Medical University, Guangzhou, China
- Ramoutar, Virin Rajiv Neil, UF Health, Jacksonville, Florida, United States
- Suliman, Sarah T., University of Florida, Jacksonville, Florida, United States
- Ilic, Ljubomir M., University of Florida College of Medicine, Jacksonville, Florida, United States
- Heilig, Charles W., University of Florida, Jacksonville, Florida, United States
Background
Mechano-Growth Factor (MGF) is expressed at baseline in normal mouse glomeruli, and is increased in type 2 and type 1 diabetic mice. Here we investigated glomerular MGF expression at both 18 and 26 weeks of Type 2 diabetes mellitus in db/db mice vs db/+ controls and the role of MC glucose uptake and PKC in this process. Mice overexpressing MGF in the glomerular MC were produced to determine its role in glomerulosclerosis (GS).
Methods
IHC for glomerular proteins using specific antibodies, with 0-4+ scoring.
P<.05 for changes. 3H2-Deoxyglucose glucose uptake rates in cultured MC. PAS stain for GS. Western analyses for MC proteins.
Results
Db/db Type 2 diabetic mice had developed GS at 18 and 26 weeks of age (increased 45%). They also had 1.9-fold increased glomerular GLUT1 and 1.7-fold increased active PKCß1, resulting in 2.4-fold excess Fibronectin (FN) and 1.7-fold excess Collagen Type IV (Col-IV). Glomerular MGF increased > 3-fold in the diabetic mice at 18 and 26 weeks. MGF-overexpression in cultured MC (i.e. MGF-S) increased GLUT1 2.6-fold, with a 67% increased glucose uptake rate and increased fibronectin (FN) 95%. 0.1mM Phloretin inhibited the excess glucose uptake in MGF-S by 57%, and suppressed the excess FN by 43%. This implicated MGF-induced glucose uptake in the excess FN production of MGF-S. 1µM Staurosporine (PKC inhibitor) suppressed the excess GLUT1 in MGF-S by 77%, and suppressed the excess glucose uptake rate by 64%. This implicated PKC activation in MGF-induced GLUT1 expression and glucose uptake. Transgenic overexpression of MGF in mouse glomerular MC’s in vivo by 2.7-fold vs controls, led to 2.3-fold increased glomerular GLUT1 and 2.4-fold increased fibronectin (FN) accumulation. MGF-transgenic adult mice exhibit 2-fold increased GS on PAS staining.
Conclusion
1.Glomerular MGF is induced in Type 2 diabetic mice at age 18 weeks and persists at 26 weeks, with increased PKCB1, GLUT1, FN and Col-IV. 2. Enhanced glucose uptake and PKC activation are involved in MGF-induced GLUT1 and FN expression in MC; 3.Transgenic mice overexpressing MGF in glomerular MC exhibited increased glomerular GLUT1 and GS with excess FN, similar to diabetic GS where glomerular MGF is also elevated.
Funding
- Commercial Support – Dialysis Clinics Inc.