Connective tissue growth factor (CTGF) expression modulates response to high glucose

PLoS One. 2013 Aug 12;8(8):e70441. doi: 10.1371/journal.pone.0070441. eCollection 2013.

Abstract

Connective tissue growth factor (CTGF) is an important mediator of fibrosis; emerging evidence link changes in plasma and urinary CTGF levels to diabetic kidney disease. To further ascertain the role of CTGF in responses to high glucose, we assessed the consequence of 4 months of streptozotocin-induced diabetes in wild type (+/+) and CTGF heterozygous (+/-) mice. Subsequently, we studied the influence of glucose on gene expression and protein in mice embryonic fibroblasts (MEF) cells derived from wildtype and heterozygous mice. At study initiation, plasma glucose, creatinine, triglyceride and cholesterol levels were similar between non-diabetic CTGF+/+ and CTGF+/- mice. In the diabetic state, plasma glucose levels were increased in CTGF+/+ and CTGF+/- mice (28.2 3.3 mmol/L vs 27.0 3.1 mmol/L), plasma triglyceride levels were lower in CTGF+/- mice than in CTGF+/+ (0.7 0.2 mmol/L vs 0.5 0.1 mmol/L, p<0.05), but cholesterol was essentially unchanged in both groups. Plasma creatinine was higher in diabetic CTGF+/+ group (11.7±1.2 vs 7.9±0.6 µmol/L p<0.01), while urinary albumin excretion and mesangial expansion were reduced in diabetic CTGF+/- animals. Cortices from diabetic mice (both CTGF +/+ and CTGF +/-) manifested higher expression of CTGF and thrombospondin 1 (TSP1). Expression of nephrin was reduced in CTGF +/+ animals; this reduction was attenuated in CTGF+/- group. In cultured MEF from CTGF+/+ mice, glucose (25 mM) increased expression of pro-collagens 1, IV and XVIII as well as fibronectin and thrombospondin 1 (TSP1). In contrast, activation of these genes by high glucose was attenuated in CTGF+/- MEF. We conclude that induction of Ctgf mediates expression of extracellular matrix proteins in diabetic kidney. Thus, genetic variability in CTGF expression directly modulates the severity of diabetic nephropathy.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood Glucose / genetics*
  • Connective Tissue Growth Factor / genetics*
  • Connective Tissue Growth Factor / metabolism*
  • Diabetes Mellitus, Experimental / genetics
  • Diabetes Mellitus, Experimental / metabolism
  • Extracellular Matrix Proteins / genetics
  • Extracellular Matrix Proteins / metabolism
  • Gene Expression
  • Gene Order
  • Gene Targeting
  • Genotype
  • Glomerular Mesangium / metabolism
  • Glucose / metabolism*
  • Kidney / metabolism
  • Kidney / pathology
  • Male
  • Mice
  • Mice, Knockout
  • Proteinuria / genetics
  • Proteinuria / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism

Substances

  • Blood Glucose
  • Extracellular Matrix Proteins
  • RNA, Messenger
  • Connective Tissue Growth Factor
  • Glucose