Real Time Cell Analysis of Model Target Cell Lines Exposed to Purified Lipoprotein (a).

Lipoprotein (a) [Lp(a)] is a novel independent cardiovascular risk factor and it includes, beyond apoB100, apolipoprotein (a), whose molecular weight is dependent on the number of genetically encoded kringle IV type 2 repeats and inversely related with Lp(a) plasma concentration. Risk thresholds for molecular weights have been proposed, but there is not a full consensus and the role of the different isoforms in pathogenesis has not yet been clarified. The aim of the present work is to explore the biological effect of low and high molecular weight Lp(a) isoforms on cultured cells. Real-time impedance analysis has been performed on model cell lines of atherogenesis and Lp(a) metabolism (THP-1, HUVEC, HASMC and HepG2) using affinity purified Lp(a) with 22 (low number) and 31 (high number) kringle IV type 2 repeats, respectively. Normalized Cell Index data show that all the cell lines tested are modified by Lp(a), though with a variable intensity. Low and high molecular weight Lp(a) isoforms at similar concentrations can exert opposite modifications on the impedance kinetics of different cell lines. These data suggest that purified Lp(a) can modify the behaviour of adherent cell lines, an effect which can be detected as impedance variation and which is influenced by its specific isoform.

Transforming growth factor-1 induces angiogenesis in vitro via VEGF production in human airway smooth muscle cells.

Increase in size and number of bronchial blood vessels as well as hyperaemia are factors that contribute to airway wall remodelling in patients with chronic airway diseases, such as asthma and chronic obstructive pulmonary diseases (COPD). Expression of transforming growth factor 1 (TGF-1), a multifunctional cytokine as well as vascular endothelial growth factor (VEGF), a key angiogenic molecule, has been shown in the inflammed airways in patients with chronic airway diseases. TGF-1 has been implicated in the regulation of extracellular matrix, leading to airway remodelling in patients with chronic airway diseases. However, the role of TGF-1 in regulating VEGF expression in patients with chronic airway diseases, as well as the underlying mechanisms are not yet well established. We investigated whether TGF-1 stimulates VEGF expression in vitro and hence could influence vascular remodelling. Cultured human airway smooth muscle cells (HASMC) were serum deprived for 60 h before incubation with 5ng/ml of TGF-1 for different time points. Control cells received serum-free culture medium. TGF‑1, treatment resulted in time dependent HASMC cell proliferation with maximal values for DNA biosynthesis at 24 h and cell number at 48 h. Northern blot analysis of VEGF mRNA expression showed increased levels in cells treated with TGF-1 for 4 to 8 h. TGF-1 also induced a time-dependent release of VEGF proteins in the conditioned medium after 48 h of treatment. Furthermore, the ability of HASMC-released VEGF proteins to induce human umbilical vein endothelial cells proliferation was inhibited by VEGF receptor antagonist, confirming that TGF-1 induced VEGF was biologically active. We conclude that TGF-1 in addition to an extracellular matrix regulator also could play a key role in bronchial angiogenesis and vascular remodelling via VEGF pathway in asthma.

Effects of p21 gene transfection in human arterial smooth muscle cells / 中国临床药理学与治疗学

AIM: To find a new way for the treatment of restenosis after coronary artery inserted stent,the effect of p21 gene transfection in human arterial smooth muscle cells(HASMCs) was investigated and its antagonistic effect of restenosis after coronary artery inserted stent was studied.METHODS:P21 gene was transfected into HASMC via Lipofectamine 2000 liposomes and the expression of its encoded protein in HASMCs was detected by immunohistochemistry.The effects of p21 gene transfection on the growth,proliferation and apoptosis of HASMCs were described by cell growth curves,the WST-1 assay and flow cytometry(FCM) analysis respectively.RESULTS: Immunohistochemical result indicated that the protein encoded by p21 gene was highly expressed in the cytoblast of HASMCs.The expression of p21 gene significantly inhibited the growth and proliferation of HASMC and remarkably promoted its apoptosis.Compared with the control group,the difference was statistically significant.CONCLUSION:These results demonstrate that the encoded protein of the p21 gene transfected into HASMCs may be involved in inhibiting cell growth and inducing apoptosis,suggesting that the technology of p21 gene transfected into HASMCs can be a new strategy to prevent and treat restenosis after coronary artery inserted stent.