Inhibitory effects of polymyxin B on NF-κB activation and expression of procollagen I, III in pre-eclamptic umbilical artery smooth muscle cells:

Preeclampsia serum-induced collagen I expression and intracellular calcium levels in arterial smooth muscle cells are mediated by the PLC-γ1 pathway

In women with preeclampsia (PE), endothelial cell (EC) dysfunction can lead to altered secretion of paracrine factors that induce peripheral vasoconstriction and proteinuria. This study examined the hypothesis that PE sera may directly or indirectly, through human umbilical vein ECs (HUVECs), stimulate phospholipase C-γ1-1,4,5-trisphosphate (PLC-γ1-IP₃) signaling, thereby increasing protein kinase C-α (PKC-α) activity, collagen I expression and intracellular Ca²⁺ concentrations ([Ca²⁺]_i) in human umbilical artery smooth muscle cells (HUASMCs). HUASMCs and HUVECs were cocultured with normal or PE sera before PLC-γ1 silencing. Increased PLC-γ1 and IP₃ receptor (IP₃R) phosphorylation was observed in cocultured HUASMCs stimulated with PE sera (P<0.05). In addition, PE serum significantly increased HUASMC viability and reduced their apoptosis (P<0.05); these effects were abrogated with PLC-γ1 silencing. Compared with normal sera, PE sera increased [Ca²⁺]_i in cocultured HUASMCs (P<0.05), which was inhibited by PLC-γ1 and IP₃R silencing. Finally, PE sera-induced PKC-α activity and collagen I expression was inhibited by PLC-γ1 small interfering RNA (siRNA) (P<0.05). These results suggest that vasoactive substances in the PE serum may induce deposition in the extracellular matrix through the activation of PLC-γ1, which may in turn result in thickening and hardening of the placental vascular wall, placental blood supply shortage, fetal hypoxia–ischemia and intrauterine growth retardation or intrauterine fetal death. PE sera increased [Ca²⁺]_i and induced PKC-α activation and collagen I expression in cocultured HUASMCs via the PLC-γ1 pathway.

In vitro toxicity of colistin on primary chick cortex neurons and its potential mechanism

Colistin is increasingly used as the last-line therapy for infections caused by Gram-negative 'superbugs'. Although colistin neurotoxicity was reported in the literature, there has no data on its mechanism. In the present study, we examined the effect of colistin on primary chick neuron cells, which were treated with 0.83, 4.15 and 8.3μg/mL colistin for 6, 12 and 24h. Cell viability was evaluated with 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assays after exposure to colistin. Formation of reactive oxygen species (ROS), nuclear morphology, caspase-3 activity and internucleosomal DNA fragmentation were examined. The results showed that, compared with the control, no significant change was observed in cell viability, ROS formation and caspase-3 activity in cells treated for 6, 12 and 24h with 0.83μg/mL colistin. However, in the 4.15 and 8.3μg/mL colistin-treated groups, the viability of chick primary neurons significantly decreased at 12 and 24h, respectively; caspase-3 activities were significantly increased to 5.1 and 7.4 fold at 6h, more earlier than the changes of ROS, which was significant increased to 124.5% and 143.5% (P<0.01) of control at 12h, respectively. The apoptosis of neuron cells was revealed by both nuclear morphological observations and internucleosomal DNA fragmentation in the 4.15 and 8.3μg/mL colistin-treated groups at 6, 12 and 24h. Our data demonstrated that colistin can induce apoptosis in primary chick cortex neurons through caspase-3 activation, which may be contributed with ROS-dependent and independent mechanism.

The "artificial artery" as in vitro perfusion model

Metabolic stimuli, pressure, and fluid shear stress (FSS) are major mediators of vascular plasticity. The exposure of the vessel wall to increased laminar FSS is the main trigger of arteriogenesis, the remodelling of pre-existent arterio-arteriolar anastomoses to functional conductance arteries. In this study, we have used an in vitro bioreactor to investigate cell-specific interactions, molecular mechanisms as well as time-dependent effects under laminar FSS conditions. This bioreactor termed “artificial artery” can be used for screening potential arterio-protective substances, pro-arteriogenic factors, and for investigating biomarkers of cardiovascular diseases such as cardiac diseases. The bioreactor is built up out of 14 hollow fiber membranes colonized with endothelial cells (HUVECs) on the inside and smooth muscle cells (HUASMCs) on the outside. By means of Hoechst 33342 staining as well as immunocytochemistry of ß-catenin and α-smooth-muscle-actin, a microporous polypropylene membrane was characterized as being the appropriate polymer for co-colonization. Defined arterial flow conditions (0.1 N/m2 and 3 N/m2), metabolic exchange, and cross-talk of HUVECs and HUASMCs through hollow fibers mimic physiological in vivo conditions of the vasculature. Analysing mono- and co-culture secretomes by MALDI-TOF-TOF mass spectrometry, we could show that HUVECs secreted Up4A upon 3 N/m2. A constant cellular secretion of randomly chosen peptides verified viability of the “artificial artery” for a cultivation period up to five days. qRT-PCR analyses revealed an up-regulation of KLF2 and TIMP1 as mechano-regulated genes and demonstrated arterio-protective, homeostatic FSS conditions by a down-regulation of EDN1. Expression analyses of VWF and EDN1 furthermore confirmed that RNA of both cell types could separately be isolated without cross-contamination. CCND1 mRNA expression in HUVECs did not change upon FSS indicating a quiescent endothelial phenotype. Taken together, the “artificial artery” provides a solid in vitro model to test pharmacological active compounds for their impact on arterio-damaging or arterio-protective properties on vascular response.

Effect of preeclampsia serum on human uterine spiral artery smooth muscle cell apoptosis in a coculture model with cytotrophoblasts

BACKGROUND/AIMS

To investigate cytotrophoblast (CTB) invasive ability and human uterine spiral artery smooth muscle cell (HUSASMC) apoptosis in a coculture model with serum from preeclamptic pregnancies.

METHODS

Transwell migration assay was used to detect the invasive ability of CTBs. Cocultured CTBs and HUSASMCs were incubated with normal or preeclamptic serum for 24 h. Monocultures of CTBs and HUSASMCs were treated identically to the cocultures and served as controls. HUSASMC viability and apoptosis rates were determined by MTT and annexin V-FITC assays. The expressions of Fas ligand (FasL) mRNA in CTBs and Fas mRNA in HUSASMCs were detected by RT-PCR. The expression of the Fas protein in HUSASMCs was detected by Western blotting.

RESULTS

In a model of CTBs cocultured with HUSASMCs, preeclamptic serum effectively decreased the invasive ability and FasL mRNA expression of the CTBs. Preeclampsia serum also increased HUSASMC viability, decreased their apoptotic rate, and decreased the expression of Fas mRNA and protein.

CONCLUSION

The abnormal invasive ability of CTBs and decreased expression of the Fas/FasL system may be directly involved in the defective remodeling of the uterine spiral arteries during preeclampsia. Furthermore, the decrease in HUSASMC apoptosis may be related to the abnormal expression of Fas/FasL.