Simvastatin has beneficial effect on pulmonary artery hypertension by inhibiting NF-κB expression

Crosstalk between the Akt/mTORC1 and NF-κB signaling pathways promotes hypoxia-induced pulmonary hypertension by increasing DPP4 expression in PASMCs

Abnormal wound healing by pulmonary artery smooth muscle cells (PASMCs) promotes vascular remodeling in hypoxia-induced pulmonary hypertension (HPH). Increasing evidence shows that both the mammalian target of rapamycin complex 1 (mTORC1) and nuclear factor-kappa B (NF-κB) are involved in the development of HPH. In this study, we explored the crosstalk between mTORC1 and NF-κB in PASMCs cultured under hypoxic condition and in a rat model of hypoxia-induced pulmonary hypertension (HPH). We showed that hypoxia promoted wound healing of PASMCs, which was dose-dependently blocked by the mTORC1 inhibitor rapamycin (5-20 nM). In PASMCs, hypoxia activated mTORC1, which in turn promoted the phosphorylation of NF-κB. Molecular docking revealed that mTOR interacted with IκB kinases (IKKs) and that was validated by immunoprecipitation. In vitro kinase assays and mass spectrometry demonstrated that mTOR phosphorylated IKKα and IKKβ separately. Inhibition of mTORC1 decreased the level of phosphorylated IKKα/β, thus reducing the phosphorylation and transcriptional activity of NF-κB. Bioinformatics study revealed that dipeptidyl peptidase-4 (DPP4) was a target gene of NF-κB; DPP4 inhibitor, sitagliptin (10-500 μM) effectively inhibited the abnormal wound healing of PASMCs under hypoxic condition. In the rat model of HPH, we showed that NF-κB activation (at 3 weeks) was preceded by mTOR signaling activation (after 1 or 2 weeks) in lungs, and administration of sitagliptin (1-5 mg/kg every day, ig) produced preventive effects against the development of HPH. In conclusion, hypoxia activates the crosstalk between mTORC1 and NF-κB, and increased DPP4 expression in PASMCs that leads to vascular remodeling. Sitagliptin, a DPP4 inhibitor, exerts preventive effect against HPH.

Relationship between the NF-κB1-94ins/del ATTG locus polymorphism and risk of hypertension in the Chinese Han population

Objective: The onset of essential hypertension is the result of a combination of genetic factors and the environment. The nuclear factor (NF)-κB1-94ins/del ATTG locus polymorphism is associated with the occurrence of various diseases. The purpose of this study was to find out the relationship between the NF-κB1-94ins/del ATTG locus polymorphism and the risk of hypertension in the Chinese Han population. Methods: A total of 585 Chinese Han patients with essential hypertension and 585 Chinese Han healthy volunteers were recruited. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was performed to analyze the genotype of the NF-κB1-94ins/del ATTG locus in all the subjects. Results: For the NF-κB1-94ins/del ATTG locus, the dominant (adjusted odds ratio [OR] = 1.31, 95% confidence interval [CI] = 1.13-1.54, P < 0.001), recessive (adjusted OR = 1.17, 95% CI = 1.02-1.32, P = 0.03) and additive (adjusted OR = 1.19, 95% CI = 1.03-1.36, P = 0.01) models showed significant increase in the risk of hypertension. The NF-κB1-94ins/del ATTG locus II genotype was an independent risk factor for hypertension (OR = 1.15, 95% CI = 0.78-1.69, P = 0.02). The interaction between the NF-κB1-94ins/del ATTG locus polymorphism and BMI, alcohol consumption, and diabetes significantly increased the risk of hypertension (OR = 1.71, 95% CI = 1.26-1.86, P < 0.01). Conclusion: The NF-κB1-94ins/del ATTG polymorphism is an independent risk factor for essential hypertension. The NF-κB1-94ins/del ATTG locus, obesity, drinking, and diabetes also interact to yield a higher risk of hypertension.

Are statins beneficial for the treatment of pulmonary hypertension?

Pulmonary hypertension (PH) is a condition characterized by vasoconstriction and vascular remodeling with a poor prognosis. The current medical treatments available are supportive care therapy and pulmonary vascular-targeted therapy. Targeted treatments for PH include prostacyclin analogs, endothelin receptor antagonists, and phosphodiesterase type 5 inhibitors; however, these treatments cannot reverse pulmonary vascular remodeling. Recently, many novel treatment options involving drugs such as statins have been emerging. In this review, we attempt to summarize the current knowledge of the role of statins in PH treatment and their potential clinical effects. Many basic researches have proved that statins can be helpful for the treatment of PH both in vitro and in experimental models. The main mechanisms underlying the effects of statins are restoration of endothelial function, attenuation of pulmonary vascular remodeling, regulation of gene expression, regulation of intracellular signaling processes involved in PH, anti-inflammatory responses, and synergy with other targeted drugs. Nevertheless, clinical researches, especially randomized controlled trials for PH are rare. The current clinical researches show contrasting results on the clinical effects of statins in patients with PH. Carefully designed randomized, controlled trials are needed to test the safety and efficacy of statins for PH treatment.

Simvastatin prevents and reverses chronic pulmonary hypertension in newborn rats via pleiotropic inhibition of RhoA signaling

Chronic neonatal pulmonary hypertension (PHT) frequently results in early death. Systemically administered Rho-kinase (ROCK) inhibitors prevent and reverse chronic PHT in neonatal rats, but at the cost of severe adverse effects, including systemic hypotension and growth restriction. Simvastatin has pleiotropic inhibitory effects on isoprenoid intermediates that may limit activity of RhoA, which signals upstream of ROCK. We therefore hypothesized that statin treatment would safely limit pulmonary vascular RhoA activity and prevent and reverse experimental chronic neonatal PHT via downstream inhibitory effects on pathological ROCK activity. Sprague-Dawley rats in normoxia (room air) or moderate normobaric hypoxia (13% O2) received simvastatin (2 mg·kg−1·day−1 ip) or vehicle from postnatal days 1–14 (prevention protocol) or from days 14–21 (rescue protocol). Chronic hypoxia increased RhoA and ROCK activity in lung tissue. Simvastatin reduced lung content of the isoprenoid intermediate farnesyl pyrophosphate and decreased RhoA/ROCK signaling in the hypoxia-exposed lung. Preventive or rescue treatment of chronic hypoxia-exposed animals with simvastatin decreased pulmonary vascular resistance, right ventricular hypertrophy, and pulmonary arterial remodeling. Preventive simvastatin treatment improved weight gain, did not lower systemic blood pressure, and did not cause apparent toxic effects on skeletal muscle, liver or brain. Rescue therapy with simvastatin improved exercise capacity. We conclude that simvastatin limits RhoA/ROCK activity in the chronic hypoxia-exposed lung, thus preventing or ameliorating hemodynamic and structural markers of chronic PHT and improving long-term outcome, without causing adverse effects.

Production of valuable compounds by molds and yeasts

We are pleased to dedicate this paper to Dr Julian E Davies. Julian is a giant among microbial biochemists. He began his professional career as an organic chemistry PhD student at Nottingham University, moved on to a postdoctoral fellowship at Columbia University, then became a lecturer at the University of Manchester, followed by a fellowship in microbial biochemistry at Harvard Medical School. In 1965, he studied genetics at the Pasteur Institute, and 2 years later joined the University of Wisconsin in the Department of Biochemistry. He later became part of Biogen as Research Director and then President. After Biogen, Julian became Chair of the Department of Microbiology at the University of British Columbia in Vancouver, Canada, where he has contributed in a major way to the reputation of this department for many years. He also served as an Adjunct Professor at the University of Geneva. Among Julian’s areas of study and accomplishment are fungal toxins including α-sarcin, chemical synthesis of triterpenes, mode of action of streptomycin and other aminoglycoside antibiotics, biochemical mechanisms of antibiotic resistance in clinical isolates of bacteria harboring resistance plasmids, their origins and evolution, secondary metabolism of microorganisms, structure and function of bacterial ribosomes, antibiotic resistance mutations in yeast ribosomes, cloning of resistance genes from an antibiotic-producing microbe, gene cloning for industrial purposes, engineering of herbicide resistance in useful crops, bleomycin-resistance gene in clinical isolates of Staphylococcus aureus and many other topics. He has been an excellent teacher, lecturing in both English and French around the world, and has organized international courses. Julian has also served on the NIH study sections, as Editor for several international journals, and was one of the founders of the journal Plasmid. We expect the impact of Julian’s accomplishments to continue into the future.

Valuable Secondary Metabolites from Fungi

Fungi are amazing producers of natural products, including secondary metabolites. These compounds are crucial to the health and well-being of people throughout the world. They also provide agriculture and livestock with many essential products. Production of secondary metabolites is improved by mutagenesis and recombinant DNA technologies allowing commercial production of these valuable compounds. This chapter centers on these fungal beneficial products, the discovery of which goes back 85 years to the time that penicillin was discovered by Alexander Fleming.

Hydrocortisone normalizes phosphodiesterase-5 activity in pulmonary artery smooth muscle cells from lambs with persistent pulmonary hypertension of the newborn

Phosphodiesterase-5 (PDE5) is the primary phosphodiesterase in the pulmonary vasculature. It degrades cyclic guanosine monophosphate (cGMP) and inhibits cGMP-mediated vasorelaxation. We previously reported that hydrocortisone treatment decreased hyperoxia-induced PDE5 activity and markers of oxidative stress in lambs with persistent pulmonary hypertension of the newborn (PPHN) ventilated with 100% O2. The objective of our study was to determine the molecular mechanism by which hydrocortisone downregulates PDE5 and oxidative stress in fetal pulmonary artery smooth muscle cells (FPASMCs) from PPHN lambs. PPHN FPASMC were incubated for 24 hours in either 21% or 95% O2. Some cells were treated with 100 nM hydrocortisone and/or ±1 μM helenalin, an inhibitor of nuclear factor κ B (NFκB), a redox-sensitive transcription factor. Exposure to hyperoxia led to increased PDE5 activity, oxidative stress, and NFκB activity. Pretreatment of PPHN FPASMC with hydrocortisone normalized PDE5 activity, decreased cytosolic oxidative stress, increased expression of extracellular superoxide dismutase and NFκB inhibitory protein, and decreased NFκB activity. Similarly, treatment with NFκB inhibitor, helenalin, decreased PDE5 activity. These data suggest that hyperoxia activates NFκB, which in turn induces PDE5 activity in PPHN FPASMC, whereas treatment with hydrocortisone attenuates these changes by blocking reactive oxygen species-induced NFκB activity.

Randomized clinical trial: atorvastatin versus placebo in patients with acute exacerbation of mild to moderate ulcerative colitis

BACKGROUND

Statins are known to possess pleiotropic anti-inflammatory properties which have been evaluated for clinical benefits in a number of disorders. Studies have demonstrated beneficial actions of statins in experimental models of colitis. Clinical evidence in acute exacerbation of ulcerative colitis (UC) is lacking.

AIM

This study aims to assess the efficacy and safety of add-on atorvastatin in mild to moderately severe acute exacerbation of UC.

METHODS

Patients with acute exacerbation of UC were randomized to receive either atorvastatin (20 mg) or matching placebo once daily orally for 8 weeks in addition to the standard therapy. Clinical efficacy was assessed by using partial Mayo score (PMS).

RESULTS

Previously diagnosed 64 cases of UC presenting with mild to moderately severe acute exacerbation were randomized to receive either atorvastatin of 20 mg or placebo. Mean PMS increased by 1.5 points and decreased by 0.31 points in atorvastatin and placebo groups, respectively, at 8 weeks compared to the baseline values (p = 0.04). Eight (25 %) and 13 (40.6 %) patients attained the primary outcome criteria for clinical improvement in the atorvastatin and placebo arms, respectively (p = 0.18). Fifteen (46.8 %) patients in the atorvastatin group and no patient in the placebo group had ≥2 point increase in PMS after 8 weeks (p < 0.001).

CONCLUSION

Atorvastatin therapy in acute exacerbation of UC may not be associated with beneficial effects. Paradoxical increase in disease activity may be seen in some patients. However, these findings need to be substantiated in larger studies.

Can statins reduce the inflammatory response associated with preterm birth in an animal model?

OBJECTIVE

The objective of the study was to determine the effect of statins on lipopolysaccharide (LPS)-induced inflammatory response in a mouse model of preterm birth (PTB).

STUDY DESIGN

Day 15 CD1 mice were randomly allocated to intraperitoneal LPS injection (100 μg) or control. Mice in the LPS group were pretreated, 16 and 2 hours prior, with pravastatin (10 μg/g), simvastatin (10 μg/g), or vehicle control. Animals were sacrificed 6 hours after LPS. Cytokine messenger ribonucleic acid (mRNA) expression in the uterus and cervix, and concentrations in the maternal serum and amniotic fluid (AF) were determined.

RESULTS

Pravastatin reduced interleukin (IL)-1β and IL-6 mRNA expression in the uterus and cervix, respectively, and serum IL-1β and granulocyte-macrophage colony-stimulating factor (GM-CSF) concentrations. Simvastatin reduced IL-1β and IL-6 mRNA expressions in the uterus, IL-6 and tumor necrosis factor alpha (TNF-α) in the cervix, and IL-1β, IL-2, IL-12p70, IL-13, TNF-α, GM-CSF, and interferon-γ concentrations in the serum and IL-6 in AF.

CONCLUSION

Statins reduce the LPS-induced inflammatory responses in a mouse model of PTB.

Emerging roles for cholesterol and lipoproteins in lung disease

Dyslipidemia, the condition of elevated serum triglycerides, elevated low-density lipoprotein cholesterol, and/or low high-density lipoprotein cholesterol, is a public health problem of growing concern. Dyslipidemia clusters with other disorders of the metabolic syndrome that together influence, and may derive from, chronic inflammation. While best recognized as a risk factor for atherosclerotic cardiovascular disease, lipid dysregulation has recently been shown to influence a variety of disease processes in several organ systems. This review highlights our current understanding of the role of cholesterol and its homeostatic trafficking in pulmonary physiology and pathophysiology. Gene-targeted mice deficient in regulatory proteins that govern reverse cholesterol transport (e.g., ATP Binding Cassette transporter G1, apolipoprotein E) have recently been shown to have abnormal lung physiology, including dysregulated pulmonary innate and adaptive immune responses to the environment. It has also recently been shown that diet-induced dyslipidemia alters trafficking of immune cells to the lung in a manner that may have important implications for the pathogenesis of acute lung injury, asthma, pneumonia, and other lung disorders. Conversely, cholesterol-targeting pharmacologic agents, such as statins, apolipoprotein mimetic peptides, and Liver X Receptor agonists, have shown early promise in the treatment of several lung disorders. An improved understanding of the precise molecular mechanisms by which cholesterol and its trafficking modify pulmonary immunity will be required before the full implications of dyslipidemia as a lung disease modifier, and the full potential of lipid-targeting agents as pulmonary therapeutics, can be realized.