Angiotensin II-induced growth of vascular smooth muscle cells is associated with modulation of cell surface area and platelet-derived growth factor receptor expression

An insight into the placental growth factor (PlGf)/angii axis in Covid-19: a detrimental intersection

Coronavirus disease 2019 (Covid-19) is a recent and current infectious pandemic caused by severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2). Covid-19 may lead to the development of acute lung injury (ALI), acute respiratory distress syndrome (ARDS), and extrapulmonary manifestations in severe cases. Down-regulation of angiotensin-converting enzyme (ACE2) by the SARS-CoV-2 increases the production of angiotensin II (AngII), which increases the release of pro-inflammatory cytokines and placental growth factor (PlGF). PlGF is a critical molecule involved in vasculogenesis and angiogenesis. PlGF is stimulated by AngII in different inflammatory diseases through a variety of signaling pathways. PlGF and AngII are interacted in SARS-CoV-2 infection resulting in the production of pro-inflammatory cytokines and the development of Covid-19 complications. Both AngII and PlGF are interacted and are involved in the progression of inflammatory disorders; therefore, we aimed in this review to highlight the potential role of the PlGF/AngII axis in Covid-19.

Large animal model of vein grafts intimal hyperplasia: A systematic review

Coronary artery bypass grafting remains the treatment of choice for a large cohort of patients with significant coronary disease. Despite the increased use of arterial grafts, the long saphenous vein remains the most commonly used conduit. Long-term graft patency continues to be the Achilles heel of saphenous vein grafts. This is due to the development of intimal hyperplasia, a chronic inflammatory disease that results in the narrowing and occlusion of a significant number of vein grafts. Research models for intimal hyperplasia are essential for a better understanding of pathophysiological processes of this condition. Large animal models resemble human anatomical structures and have been used as a surrogate to study disease development and prevention over the years. In this paper, we systematically review all published studies that utilized large animal models of vein graft disease with a focus on the type of model and any therapeutic intervention, specifically the use of external stents/mesh.

Resveratrol inhibits angiotensin II-induced ERK1/2 activation by downregulating quinone reductase 2 in rat vascular smooth muscle cells

Our previous studies showed that resveratrol could inhibit the proliferation of vascular smooth muscle cells (VSMCs) and repress mRNA and protein expression of quinone reductase 2 (NQO2). This study further explored the potential mechanisms whereby resveratrol inhibits the proliferation of rat VSMCs. Lentiviral vectors that incorporated NQO2 small interfering RNA (siRNA) were constructed and transduced into rat VSMCs. The cell proliferation was detected using the bromodeoxyuridine (BrdU) assay. Cultured rat VSMCs were stimulated with angiotensin II and the level of reactive oxygen species (ROS) was measured using a ROS assay kit. A realtime quantitative PCR was used to detect NQO2 mRNA levels. Extracellular signal-regulated kinase (ERK1/2) and NQO2 protein expression were determined by Western blotting analysis. The inhibitory effect of resveratrol (10 and 50 µmol/L) on the proliferation of rat VSMCs in the NQO2 siRNA group was significantly weaker than that in the normal and scrambled siRNA group (P < 0.01). The ROS level in the NQO2 siRNA and resveratrol (50 µmol/L) treatment groups were lower than that in the normal and scrambled siRNA groups (P < 0.01 in both). Compared with the normal and scrambled siRNA group, the phosphorylation of ERK1/2 was significantly decreased in the NQO2 siRNA and resveratrol (50 µmol/L) treatment group (P < 0.01 in both). In conclusion, high concentration of resveratrol inhibits angiotensin II-induced ERK1/2 phosphorylation and subsequent proliferation by down-regulation of NQO2 in cultured rat VSMCs.

Angiotensin II upregulates the expression of placental growth factor in human vascular endothelial cells and smooth muscle cells

Background

Atherosclerosis is now recognized as a chronic inflammatory disease. Angiotensin II (Ang II) is a critical factor in inflammatory responses, which promotes the pathogenesis of atherosclerosis. Placental growth factor (PlGF) is a member of the vascular endothelial growth factor (VEGF) family cytokines and is associated with inflammatory progress of atherosclerosis. However, the potential link between PlGF and Ang II has not been investigated. In the current study, whether Ang II could regulate PlGF expression, and the effect of PlGF on cell proliferation, was investigated in human vascular endothelial cells (VECs) and smooth muscle cells (VSMCs).

Results

In growth-arrested human VECs and VSMCs, Ang II induced PlGF mRNA expression after 4 hour treatment, and peaked at 24 hours. 10^-6 mol/L Ang II increased PlGF protein production after 8 hour treatment, and peaked at 24 hours. Stimulation with Ang II also induced mRNA expression of VEGF receptor-1 and -2(VEGFR-1 and -2) in these cells. The Ang II type I receptor (AT₁R) antagonist blocked Ang II-induced PlGF gene expression and protein production. Several intracellular signals elicited by Ang II were involved in PlGF synthesis, including activation of protein kinase C, extracellular signal-regulated kinase 1/2 (ERK1/2) and PI3-kinase. A neutralizing antibody against PlGF partially inhibited the Ang II-induced proliferation of VECs and VSMCs. However, this antibody showed little effect on the basal proliferation in these cells, whereas blocking antibody of VEGF could suppress both basal and Ang II-induced proliferation in VECs and VSMCs.

Conclusion

Our results showed for the first time that Ang II could induce the gene expression and protein production of PlGF in VECs and VSMCs, which might play an important role in the pathogenesis of vascular inflammation and atherosclerosis.