Kidney international
-
Kidney international · Oct 1999
The transforming growth factor-beta/SMAD signaling pathway is present and functional in human mesangial cells.
Transforming growth factor-beta (TGF-beta) signals through a unique set of intracellular proteins, called SMADs, that have been characterized mainly in transient overexpression systems. Because several models of glomerulosclerosis suggest a role for TGF-beta in the extracellular matrix accumulation, we sought to characterize the role of SMAD proteins in mediating TGF-beta1 responses in a more physiological system using nontransformed human mesangial cells. ⋯ Smad2, Smad3, and Smad4 are present and activated by TGF-beta1 in human mesangial cells. The SMAD pathway is functional in these cells and appears to be involved in TGF-beta1-induced type I collagen gene transcription. These findings raise the possibility that SMAD signaling plays a role in glomerular matrix accumulation.
-
Kidney international · Oct 1999
Latin American nephrology: scientific production and impact of the publications.
During the last two decades, there has been a significant change in the origin and impact of the world's biomedical scientific production, particularly in countries in which the investment in research accounts for an important portion of the gross national product (GNP). However, in less developed countries, budget restrictions and the lack of policies toward research may determine a limited growth of the scientific production. ⋯ This study indicates that although efforts toward improving the quantity and quality of research in Latin America have been made, the final results are less than other regions in the world. Possible factors responsible for the low performance include a failure in academic motivation and lack of pressure for publication, as well as limited research funding. Therefore, important efforts from local and international nephrological communities are needed to boost research in Latin America.
-
Kidney international · Oct 1999
Induction of heat shock protein 70 protects mesangial cells against oxidative injury.
The heat shock response is an immediate cellular response to elevated temperatures and other types of injury that consists of the synthesis of so-called heat shock protein (hsp). This study was designed to investigate the production and the protective role of the 70 kDa hsp (hsp70) in cultured rat mesangial cells. When mesangial cells undergo thermal (45 degrees C, 15 min) stimulation, they express hsp70 mRNA expression and increased hsp70 protein production. ⋯ Furthermore, when mesangial cells were preconditioned by heat shock, subsequent oxidative injury caused less inhibition of cell survival and cellular proliferation. Pretreatment of cells with quercetin, a transcription inhibitor, abolished the protective effect of heat shock on subsequent oxidative injury. We conclude that heat shock, not oxidative injury, induces hsp70 in mesangial cells, and this induction of hsp70 protects mesangial cells against subsequent oxidative injury.