scholarly journals Smad7-dependent Regulation of Heme Oxygenase-1 by Transforming Growth Factor-β in Human Renal Epithelial Cells

2000 ◽  
Vol 275 (52) ◽  
pp. 40904-40909 ◽  
Author(s):  
Nathalie Hill-Kapturczak ◽  
Leigh Truong ◽  
Vijayalakshmi Thamilselvan ◽  
Gary A. Visner ◽  
Harry S. Nick ◽  
...  
2013 ◽  
Vol 288 (28) ◽  
pp. 20658-20667 ◽  
Author(s):  
Yukari Okita ◽  
Atsushi Kamoshida ◽  
Hiroyuki Suzuki ◽  
Ken Itoh ◽  
Hozumi Motohashi ◽  
...  

2007 ◽  
Vol 293 (3) ◽  
pp. F885-F894 ◽  
Author(s):  
Amie Traylor ◽  
Thomas Hock ◽  
Nathalie Hill-Kapturczak

Excess transforming growth factor-β1 (TGF-β1) in the kidney leads to increased cell proliferation and deposition of extracellular matrix, resulting in progressive kidney fibrosis. TGF-β1, however, stabilizes and attenuates tissue injury through the activation of cytoprotective proteins, including heme oxygenase-1 (HO-1). HO-1 catabolizes pro-oxidant heme into substances with anti-oxidant, anti-apoptotic, anti-fibrogenic, vasodilatory and immune modulatory properties. Little is known regarding the molecular regulation of human HO-1 induction by TGF-β1 except that it is dependent on de novo RNA synthesis and requires a group of structurally related proteins called Smads. It is not known whether other DNA binding proteins are required to initiate transcription of HO-1 and, furthermore, the promoter region(s) involved in TGF-β1-mediated induction of HO-1 has not been identified. The purpose of this study was to further delineate the molecular regulation of HO-1 by TGF-β1 in human renal proximal tubular cells. Actinomycin D and nuclear run-on studies demonstrate that TGF-β1 augments HO-1 expression by increased gene transcription and does not involve increased mRNA stability. Using transient transfection, mithramycin A, small interfering RNA, electrophoretic mobility shift assays, and decoy oligonucleotide experiments, a TGF-β1-responsive region is identified between 9.1 and 9.4 kb of the human HO-1 promoter. This ∼280-bp TGF-β1-responsive region contains a putative Smad binding element and specificity protein 1 binding sites, both of which are required for human HO-1 induction by TGF-β1.


1993 ◽  
Vol 264 (4) ◽  
pp. F623-F628 ◽  
Author(s):  
F. Law ◽  
R. Rizzoli ◽  
J. P. Bonjour

The effect(s) of transforming growth factor-beta (TGF-beta) on Pi transport was investigated in confluent opossum kidney (OK) epithelial cells. TGF-beta induced a time- and concentration-dependent decrease in the initial rate of sodium-dependent Pi, but not alanine, transport. This selective inhibitory effect on Pi transport was largely reversible and was not associated with a rise in adenosine 3',5'-cyclic monophosphate production. The reduction in Pi uptake was also independent of changes in extracellular calcium concentrations and prostaglandin synthesis. TGF-beta-mediated Pi transport inhibition appeared to involve neither pertussis toxin-sensitive G protein(s) nor augmented protein kinase C activity. However, the probable role of a serine/threonine protein kinase in signal transduction was supported by the considerable attenuation of TGF-beta effect by H-7. Furthermore, the TGF-beta-induced Pi transport reduction was blunted by cycloheximide and abolished by actinomycin D. In conclusion, TGF-beta selectively inhibits the activity of the sodium-dependent Pi transport system present in the apical membrane of renal epithelial cells. This action appears to be exerted via an unprecedented inhibitory pathway that might involve a serine/threonine protein kinase and alterations in the transcriptional and translational processes.


2020 ◽  
Vol 217 (3) ◽  
Author(s):  
Nikolaos G. Frangogiannis

TGF-β is extensively implicated in the pathogenesis of fibrosis. In fibrotic lesions, spatially restricted generation of bioactive TGF-β from latent stores requires the cooperation of proteases, integrins, and specialized extracellular matrix molecules. Although fibroblasts are major targets of TGF-β, some fibrogenic actions may reflect activation of other cell types, including macrophages, epithelial cells, and vascular cells. TGF-β–driven fibrosis is mediated through Smad-dependent or non-Smad pathways and is modulated by coreceptors and by interacting networks. This review discusses the role of TGF-β in fibrosis, highlighting mechanisms of TGF-β activation and signaling, the cellular targets of TGF-β actions, and the challenges of therapeutic translation.


Sign in / Sign up

Export Citation Format

Share Document