Effect of Native and Modified Lipoproteins, and Albumin on Human Mesangial Cell Proliferation

Sohn, Il Suk; Lee, Tae Won; Park, Jae Kyung; Kim, Hee Jin; Cho, Byung Soo; Ihm, Chun Gyoo; Kim, Myung Jae

Abstract

BACKGROUND: Modified lipoproteins may be involved in nephro- and glomerulosclerosis. Diabetic nephropathy-like lesions have also been induced in a rat model by glycated and glycoxidized albumin. In cultured rat or human mesangial cells, enhanced cell proliferation and production of mesangial matrix in response to lipoproteins and their modified forms have been demonstrated by [3H]-thymidine incorporation and cell counting assays. But these methods are relatively complex and most of them have used only one or two of the lipoprotein, albumin and their modified forms.
METHODS
We investigated the effects of native and modifed lipoproteins, and albumin on cultured human mesangial cell proliferation using non-radioactive colorimetric method by MTS/PMS assay. Lipoproteins added were low density lipoprotein(LDL), high density lipoprotein(HDL), very low density lipoprotein(VLDL), oxidized LDL(oxidation with copper sulfate in vitro) and glycated LDL and we also used albumin, glycated albumin, and interleukin-1beta as a positive control.
RESULTS
Interleukin-1beta promoted the proliferation of cultured human mesangial cells up to concentration 20 ng/mL. LDL induced the proliferation of mesangial cells in a concentration-dependent manner up to concentration 100 microgram/mL. HDL and VLDL had no significant proliferative effect. Oxidized LDL caused the proliferation of mesangial cells at low concentration up to concentration 25 microgram/mL. Addition of glycated LDL resulted in a concentration- dependent inhibition of mesangial cells. Albumin and glycated albumin inhibited the proliferation of mesangial cells at low concentration of 100 microgram/mL, but cell growth was increased at higher concentrations.
CONCLUSION
We demonstrated the effects of the single and modified proteins on the proliferation of cultured human mesangial cell by relatively simple colorimetric method. Results were almostly identical to those of previous studies obtained by radioactive method or cell counting assay.