Abstract: FR-PO713

Connective Tissue Growth Factor (CTGF, CCN2) Is Sufficient to Drive Expression of Collagen IV, Fibronectin and Mesangial Expansion

Session Information

Category: Glomerular

  • 1002 Glomerular: Basic/Experimental Pathology

Authors

  • Gao, Yongxin, University of Florida, Jacksonville, Florida, United States
  • Heilig, Charles W., University of Florida, Jacksonville, Florida, United States
  • James, Leighton R., University of Florida, Jacksonville, Florida, United States
Background


CTGF has been linked to organ fibrosis. Using an animal model and cultured mouse embryonic fibroblast, we previously demonstrated that CTGF expression modulates response to hyperglycemia and diabetes mellitus. Accordingly, we hypothesized that CTGF directly influences expression of extracellular matrix protein to drive glomerulosclerosis. To test our hypothesis, we used animals that express 1 to 4 copies of mice CTGF gene to assess a) levels of ECM proteins (Fibronectin [Fn] and Collagen IV [Coll IV]), vascular endothelial growth factor (VEGF), mechano growth factor (MGF), as well as, b) mesangial expansion and.fibrosis.

Methods

CTGF knockout and gene-duplicated mice were generated using standard gene-targeting methodologies. Mice harboring 1 to 4 copies of CTGF were generated through breeding and have been previously described. Lysates were obtained from Kidney cortices retrieved from 6-month old mice and used for immunoblotting analysis of CTGF, Collagen IV, Fn, VEGF and MGF. Histologic examination was performed on fixed kidney sections using Hematoxylin and eosin (H&E), Periodic-schiff and Mason-trichrome staining. Immunohistochemistry utilized CTGF antibody and flourescent labelled secondary antibody.

Results

There was a graded increase in CTGF (3.5-fold), Coll IV (4-fold), Fn (7-fold), VEGF (8-fold) and MGF (7-fold) in 4-copy mice when compared with heterozygous (1-copy) animals. In addition, we observed mesangial matrix expansion and increased mesangial and perivascular fibrosis in kidney from 4-copy animals as compared with heterozygous and wild-type mice.

Conclusion

Graded CTGF expression directly increases expression of collagen, fibronectin, VEGF and MGF in mice kidney. Increased peri-vascular and glomerular sclerosis links CTGF expression with fibrosis, blood pressure and urine protein excretion previously observed in these models.

Funding

  • Private Foundation Support