Kidney Week

Abstract: SA-PO312

Mechano-Growth Factor (MGF) Mediation of Glomerulosclerosis (GS) Involves Activation of PKC

Session Information

• Cellular Crosstalk in Glomerular Diseases - II
  October 27, 2018 | Location: Exhibit Hall, San Diego 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

Yongxin Gao,

• Bueno, Emma P., UF COM- Jacksonville, Jacksonville, Florida, United States

Emma P. Bueno,

• Shin, Nanjoo, University of Florida, Jacksonville, Florida, United States

Nanjoo Shin,

• James, Leighton R., UF COM- Jacksonville, Jacksonville, Florida, United States

Leighton R. James,

• Heilig, Charles W., UF COM- Jacksonville, Jacksonville, Florida, United States

Charles W. Heilig,

Background

We previously reported PKC ß1 and PKC a activation in our non-diabetic GS mouse model Fvb Os/+, with reduced glomerular numbers, glomerular hypertension, and increased SNGFR. GS develops rapidly after birth leading to renal failure and premature demise. MGF is expressed in the glomeruli and is responsive to stretch in other tissues. Here we investigate MGF expression in Fvb Os/+ glomeruli, in cultured Fvb Os/+ mesangial cells(MC), and potential MGF-regulation of PKC activation. We hypothesize that MGF activation of PKC may explain the GS in Fvb Os/+ mice and excess extracellular matrix (ECM) in cultured Fvb Os/+ mesangial cells (MC).

Methods

1.Fvb Os/+ and Fvb +/+ mouse kidneys were harvested and fixed at age 4 weeks for PAS staining and immunolabelling (0 - 4+) for MGF, active PKC ß1 and active PKC a; Total glomerular or MC proteins were also isolated for Western analyses of selected proteins then semiquantitated. 2. Primary culture MC’s from mice of both genotypes were grown to 80-100 % confluence in DMEM medium 8mM glucose,10% FBS at 37 C and 5% CO₂. 3.Normal mouse MC’s transduced (pWZLneo MoMuLV expression vector) to overexpress (MGF-S), or suppress (MGF-AS) MGF were examined with Western analyses to investigate potential PKC regulation by MGF. 4.Mean ± SEM was determined and statistical analyses performed with one way ANOVA, & Students T-test where indicated.

Results

1.Fvb Os/+ glomeruli exhibited > 2-fold (P < .005) increase in glomerular MGF vs. control. 2.Fvb Os/+ MC’s had 1.6-fold elevated MGF (P < 0.05), with increased active PKC ß1 (3.5-fold, P < 0.005) and active PKC a (2.9-fold , P < 0.005). This correlated with increased fibronectin (FN) and Type IV collagen (Col-IV) in the cells. 3.MGF-S had 4.5-fold overexpression of MGF protein, (P < 0.02), with increased active PKC ß1 (4-fold, P < 0.05) and PKC a (4-fold P < 0.05). MGF-AS had 50% suppression of basal PKCß1.

Conclusion

1.Increased MGF was observed in FvbOs/+ glomeruli and cultured Fvb Os/+ MC, correlating with PKC B1 and PKC a activation in both. High MGF and PKC activation were maintained with passage of Fvb Os/+ MC in vitro, associated with high FN and Col-IV. 2.MGF-S also exhibited activation of PKC ß1 and PKC a, which may mediate the increased ECM in these cells as well.

Funding

• Commercial Support – Dialysis Clinics Inc.