Increased transforming growth factor-beta1 circulating levels and production in human monocytes after 3-hydroxy-3-methyl-glutaryl-coenzyme a reductase inhibition with pravastatin
Ettore Porreca, MD*,*,
Concetta Di Febbo, MD*,
Giovanna Baccante, PhD*,
Marcello Di Nisio, MD* and
Franco Cuccurullo, MD*
* Department of Medicine and Aging, Atherosclerosis and Thrombosis Section, University of Chieti Medical School, Chieti, Italy
View larger version (14K):
[in a new window]
|
Figure 1 Scatterplot showing transforming growth factor-beta1 (TGF-beta1) plasma levels in hypercholesterolemic patients (n = 18) before treatment (baseline) and after diet plus pravastatin (40 mg/day) or diet alone for four to six weeks.
|
|
View larger version (15K):
[in a new window]
|
Figure 2 Scatterplots showing the relationships between transforming growth factor-beta1 (TGF-beta1) plasma levels and low-density lipoprotein (LDL) (top) and total cholesterol (bottom) levels in hypercholesterolemic patients (n = 18).
|
|
View larger version (15K):
[in a new window]
|
Figure 3 Production of transforming growth factor-beta1 (TGF-beta1) in the monocytes of hypercholesterolemic patients (n = 9) at baseline and after four to six weeks of diet plus pravastatin (40 mg/day) treatment. A conditioned medium of unstimulated cultures was collected after 24 h, and the biologic activity of TGF-beta1 was evaluated after acidification for mink-lung epithelial cell bioassay. Mink-lung cells respond to TGF-beta1 released in the culture medium, with a decrease in deoxyribonucleic acid synthesis, as evaluated by 3H-thymidine incorporation. A comparison with the standard curve and multiplication by the dilution factor (1:10) yielded TGF-beta1 concentration (ng/ml) in the conditioned medium of monocyte cultures.
|
|
View larger version (30K):
[in a new window]
|
Figure 4 The effect of pravastatin (Prava) and mevalonate (MEV) on the production and messenger ribonucleic acid (mRNA) levels of transforming growth factor-beta1 (TGF-beta1). (A) Bioassay of TGF-beta1 activity in a conditioned medium of monocyte cultures incubated with pravastatin (1–10 µM) or pravastatin (5 µM) plus mevalonate (100 µM). A conditioned medium from the cultures was collected after 24 h and acidified for mink-lung epithelial cell bioassay. Mink-lung cells respond to TGF-beta1 released in the culture medium, with a dose-dependent decrease in deoxyribonucleic acid (DNA) synthesis, as evaluated by 3H-thymidine incorporation. A comparison with the standard curve and multiplication by the dilution factor (1:10) yielded a dose-dependent increase in the TGF-beta1 concentration (ng/ml) in the conditioned medium of monocyte cultures. Mevalonate reversed the TGF-beta1–dependent effect on mink-lung cells. The results are expressed as the mean value ± SD of three independent experiments performed in triplicate. Comparisons among treatment conditions were carried out by analysis of variance, followed by Dunnett’s test. *p < 0.05, **p < 0.01 and p = NS versus untreated (control) cells. (B) Representative Northern blot analysis of TGF-beta1 and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA in human peripheral blood monocytes after incubation with pravastatin (5 µM) alone or mevalonate (100 µM) together with pravastatin (5 µM). Mononuclear cells were cultured 24 h in serum-free conditions. Total RNA (5 µg per lane) was electrophoresed on 1.5% formaldehyde agarose gels, transferred to nitrocellulose and hybridized with 32P random primer-labeled TGF-beta1 complementary DNA. The sizes of the transcripts were determined by comparison with 28S and 18S ribosomal RNA. Molecular size markers are shown on the left. Lane 1 = untreated cells; lane 2 = pravastatin-treated cells; and lane 3 = cell treated with pravastatin plus mevalonate. Quantitative data obtained from imaging are expressed in arbitrary units.
|
|
|
