Blockade of thrombospondin-1 ameliorates high glucose-induced peritoneal fibrosis through downregulation of TGF-β1/Smad3 signaling pathway.

Abstract

BACKGROUND:

Transforming growth factor-β1 (TGF-β1) is a profibrotic cytokine which induces mesothelial cell mesothelial-to-mesenchymal transition (MMT) and peritoneal fibrosis in patients receiving treatment of peritoneal dialysis. Because thrombospondin-1 (TSP-1) is able to activate latent TGF-β1 in vivo, we investigated whether blockade of TSP-1 could modulate mesothelial cell MMT and ameliorate peritoneal fibrosis.

METHODS:

Human pleural mesothelial cells (Met-5A cells) were treated with TSP-1 and addition of TGF-β1 neutralizing antibody to assess the effect of TSP-1 on MMT. Furthermore, TSP-1 blocking peptide Leu-Ser-Lys-Leu (LSKL) was applied to Met-5A cells treated with 4.25% d-glucose to determine its function in high glucose-induced MMT. Consequently, a uremic dialysate injection rat model was set up to confirm the results in vivo.

RESULTS:

Exposure of Met-5A cells to TSP-1 increased TGF-β1 secretion, expression and bioactivity, triggered Smad3 phosphorylation, upregulated the expression of mesenchymal molecules including fibronectin, collagen type III, α-smooth muscle actin, Snail, and decreased calretinin expression. The effect was partially attenuated by TGF-β1 neutralizing antibody. TSP-1 expression in Met-5A cells was increased by 4.25% d-glucose, followed by increased secretion and bioactivity of TGF-β1, the onset of Smad3 phosphorylation and induction of MMT. LSKL significantly attenuated high glucose-mediated mesothelial cell MMT and ameliorated peritoneal fibrosis in uremic rats receiving dextrose dialysate injection.

CONCLUSIONS:

Taken together, these data demonstrated that TSP-1 contributes to mesothelial cell MMT by activating TGF-β1/Smad3 signaling pathway and blockade of TSP-1 attenuates high glucose-mediated mesothelial cell MMT and peritoneal fibrosis.

• Authors: Na Jiang, Zhen Zhang, Xinghua Shao, Ran Jing, Chunlin Wang, Wei Fang, Shan Mou, Zhaohui Ni
• Journal: Journal of cellular physiology (J Cell Physiol) Vol. 235 Issue 1 Pg. 364-379 (01 2020) ISSN: 1097-4652 [Electronic] United States
• PMID: 31236971 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2019 Wiley Periodicals, Inc.

Chemical References

• Antibodies, Neutralizing
• SMAD3 protein, human
• Smad3 Protein
• TGFB1 protein, human
• Thrombospondin 1
• Transforming Growth Factor beta1
• Glucose

Topics

• Animals
• Antibodies, Neutralizing (pharmacology)
• Cell Differentiation (physiology)
• Cell Line
• Down-Regulation (genetics)
• Epithelial Cells (cytology)
• Glucose
• Humans
• Male
• Peritoneal Dialysis (adverse effects)
• Peritoneal Fibrosis (chemically induced, genetics, pathology)
• Rats
• Rats, Sprague-Dawley
• Signal Transduction (physiology)
• Smad3 Protein (metabolism)
• Thrombospondin 1 (antagonists & inhibitors)
• Transforming Growth Factor beta1 (metabolism)