Lentiviral-Mediated shRNA Silencing of PDE4D Gene Inhibits Platelet-Derived Growth Factor-Induced Proliferation and Migration of Rat Aortic Smooth Muscle Cells

GENDER DISPARITIES OF CIRCULATORY DISEASE PROGRESS IN THE CHORNOBYL ACCIDENT CLEAN-UP WORKERS AND PHOSPHODIESTERASE 4D GENE rs966221 POLYMORPHISM

OBJECTIVE

Evaluation of the hypertensive disease (HD) and coronary heart disease (CHD) progress in the ChornobylNPP (ChNPP) accident clean-up workers (ACUW) and persons not exposed to ionizing radiation depending on gen-der and genotype of the phosphodiesterase 4D (PDE4D) gene rs966221 polymorphism.

MATERIALS AND METHODS

There were male ACUW (ACUWm; n=515) and female ACUW (ACUWf; n=145) involved in thestudy since 2013 till 2018. Participation in the clean-up works took place in 1986-1987. The control group includ-ed male (CGm; n=162) and female (CGf; n=120) persons not exposed to ionizing radiation. All study subjects havehad neither signs nor symptoms of HD or CHD before the ChNPP accident.

RESULTS

Review of the Kaplan-Meier survival tables indicated that according to median survival the HD emerged inACUWm and ACUWf in a younger age (47.5 ± 0.6 and 50.7 ± 0.7 years old, respectively) vs. CGm or CGf (54.9 ± 1.1 and54.4 ± 1.1 years, respectively). The same was true for CHD where the median values were (56.8 ± 0.5), (61.2 ± 0.8),(61.6 ± 1.0) and (64.2 ± 1.4) years respectively. Review of cumulative incidence of HD and CHD revealed no associ-ation of the PDE4D gene rs966221 polymorphism with the diseases of concern. The TT gene carrier state comparedto the CC or CT genes features an increased risk of myocardial infarction (MI) 2.9 times in ACUWm, 4-fold in CGm, and5.5 times in CGf (p < 0.05). No any gene carrier state was associated with MI in the ACUWf. Onset of menopause wasfollowed by an increase in HD incidence vs. males.

CONCLUSIONS

The male and female ChNPP ACUW were developing HD and CAD at a younger age compared with cor-responding non-irradiated control. In male ACUW in comparison with female ACUW the cumulative morbidity ratefor MI was higher in any age range, whereas for CAD it was higher from 23 to 74 years, and for HD from 25 to 53 yearsof age. In male and female ACUW as well as in non-irradiated control the HD developed much earlier than CHD. Thecarrier state of TT genotype of PDE4D gene rs966221 polymorphism increases the risk of MI in males of all ages, inthe non-irradiated controls it is increased in 65 years for men and in 60 years for women. No data on association ofthe genotype of the described gene polymorphism with MI were found in female ACUW.

The Hippo pathway mediates inhibition of vascular smooth muscle cell proliferation by cAMP

AIMS

Inhibition of vascular smooth muscle cell (VSMC) proliferation by intracellular cAMP prevents excessive neointima formation and hence angioplasty restenosis and vein-graft failure. These protective effects are mediated via actin-cytoskeleton remodelling and subsequent regulation of gene expression by mechanisms that are incompletely understood. Here we investigated the role of components of the growth-regulatory Hippo pathway, specifically the transcription factor TEAD and its co-factors YAP and TAZ in VSMC.

METHODS AND RESULTS

Elevation of cAMP using forskolin, dibutyryl-cAMP or the physiological agonists, Cicaprost or adenosine, significantly increased phosphorylation and nuclear export YAP and TAZ and inhibited TEAD-luciferase report gene activity. Similar effects were obtained by inhibiting RhoA activity with C3-transferase, its downstream kinase, ROCK, with Y27632, or actin-polymerisation with Latrunculin-B. Conversely, expression of constitutively-active RhoA reversed the inhibitory effects of forskolin on TEAD-luciferase. Forskolin significantly inhibited the mRNA expression of the pro-mitogenic genes, CCN1, CTGF, c-MYC and TGFB2 and this was reversed by expression of constitutively-active YAP or TAZ phospho-mutants. Inhibition of YAP and TAZ function with RNAi or Verteporfin significantly reduced VSMC proliferation. Furthermore, the anti-mitogenic effects of forskolin were reversed by overexpression of constitutively-active YAP or TAZ.

CONCLUSION

Taken together, these data demonstrate that cAMP-induced actin-cytoskeleton remodelling inhibits YAP/TAZ-TEAD dependent expression of pro-mitogenic genes in VSMC. This mechanism contributes novel insight into the anti-mitogenic effects of cAMP in VSMC and suggests a new target for intervention.

cAMP-induced actin cytoskeleton remodelling inhibits MKL1-dependent expression of the chemotactic and pro-proliferative factor, CCN1

Elevation of intracellular cAMP concentration has numerous vascular protective effects that are in part mediated via actin cytoskeleton-remodelling and subsequent regulation of gene expression. However, the mechanisms are incompletely understood. Here we investigated whether cAMP-induced actin-cytoskeleton remodelling modulates VSMC behaviour by inhibiting expression of CCN1. In cultured rat VSMC, CCN1-silencing significantly inhibited BrdU incorporation and migration in a wound healing assay. Recombinant CCN1 enhanced chemotaxis in a Boyden chamber. Adding db-cAMP, or elevating cAMP using forskolin, significantly inhibited CCN1 mRNA and protein expression in vitro; transcriptional regulation was demonstrated by measuring pre-spliced CCN1 mRNA and CCN1-promoter activity. Forskolin also inhibited CCN1 expression in balloon injured rat carotid arteries in vivo. Inhibiting RhoA activity, which regulates actin-polymerisation, by cAMP-elevation or pharmacologically with C3-transferase, or inhibiting its downstream kinase, ROCK, with Y27632, significantly inhibited CCN1 expression. Conversely, expression of constitutively active RhoA reversed the inhibitory effects of forskolin on CCN1 mRNA. Furthermore, CCN1 mRNA levels were significantly decreased by inhibiting actin-polymerisation with latrunculin B or increased by stimulating actin-polymerisation with Jasplakinolide. We next tested the role of the actin-dependent SRF co-factor, MKL1, in CCN1 expression. Forskolin inhibited nuclear translocation of MKL1 and binding of MKL1 to the CCN1 promoter. Constitutively-active MKL1 enhanced basal promoter activity of wild-type but not SRE-mutated CCN1; and prevented forskolin inhibition. Furthermore, pharmacological MKL-inhibition with CCG-1423 significantly inhibited CCN1 promoter activity as well as mRNA and protein expression. Our data demonstrates that cAMP-induced actin-cytoskeleton remodelling regulates expression of CCN1 through MKL1: it highlights a novel cAMP-dependent mechanism controlling VSMC behaviour.

Epigallocatechin gallate attenuates proliferation and oxidative stress in human vascular smooth muscle cells induced by interleukin-1β via heme oxygenase-1

Proliferation of vascular smooth muscle cells (VSMCs) triggered by inflammatory stimuli and oxidative stress contributes importantly to atherogenesis. The association of green tea consumption with cardiovascular protection has been well documented in epidemiological observations, however, the underlying mechanisms remain unclear. This study aimed to elucidate the effects of the most active green tea catechin derivative, (−)-epigallocatechin-3-gallate (EGCG), in human aortic smooth muscle cells (HASMCs), focusing particularly on the role of a potent anti-inflammatory and antioxidative enzyme heme oxygenase-1 (HO-1). We found that pretreatment of EGCG dose- and time-dependently induced HO-1 protein levels in HASMCs. EGCG inhibited interleukin- (IL-)1β-induced HASMC proliferation and oxidative stress in a dose-dependent manner. The HO-1 inducer CoPPIX decreased IL-1β-induced cell proliferation, whereas the HO-1 enzyme inhibitor ZnPPIX significantly reversed EGCG-caused growth inhibition in IL-1β-treated HASMCs. At the molecular level, EGCG treatment significantly activated nuclear factor erythroid-2-related factor (Nrf2) transcription activities. These results suggest that EGCG might serve as a complementary and alternative medicine in the treatment of these pathologies by inducing HO-1 expression and subsequently decreasing VSMC proliferation.