Rather than being a constitutive enzyme as was first suggested, endothelial nitric oxide synthase (eNOS) is dynamically regulated at the transcriptional, posttranscriptional, and posttranslational levels. This review will focus on how changes in eNOS function are conferred by various posttranslational modifications. The latest knowledge regarding eNOS targeting to the plasma membrane will be discussed as the role of protein phosphorylation as a modulator of catalytic activity. Furthermore, new data are presented that provide novel insights into how disruption of the eNOS dimer prevents eNOS uncoupling and the production of superoxide under conditions of elevated oxidative stress and identifies a novel regulatory region we have termed the ‘flexible arm’.

Oxygen delivery by Hb is essential for vertebrate life. Three amino acids in Hb are strictly conserved in all mammals and birds, but only two of those, a His and a Phe that stabilize the heme moiety, are needed to carry O2. The third conserved residue is a Cys within the β-chain (βCys93) that has been assigned a role in S-nitrosothiol (SNO)-based hypoxic vasodilation by RBCs. Under this model, the delivery of SNO-based NO bioactivity by Hb redefines the respiratory cycle as a triune system (NO/O2/CO2). However, the physiological ramifications of RBC-mediated vasodilation are unknown, and the apparently essential nature of βCys93 remains unclear. Here we report that mice with a βCys93Ala mutation are deficient in hypoxic vasodilation that governs blood flow autoregulation, the classic physiological mechanism that controls tissue oxygenation but whose molecular basis has been a longstanding mystery. Peripheral blood flow and tissue oxygenation are decreased at baseline in mutant animals and decline excessively during hypoxia. In addition, βCys93Ala mutation results in myocardial ischemia under basal normoxic conditions and in acute cardiac decompensation and enhanced mortality during transient hypoxia. Fetal viability is diminished also. Thus, βCys93-derived SNO bioactivity is essential for tissue oxygenation by RBCs within the respiratory cycle that is required for both normal cardiovascular function and circulatory adaptation to hypoxia.

Antiphospholipid Abs (APLAs) are associated with thrombosis and recurrent fetal loss. These Abs are primarily directed against phospholipid-binding proteins, particularly ␤ 2 GPI, and activate endothelial cells (ECs) in a ␤ 2 GPI-dependent manner after binding of ␤ 2 GPI to EC annexin A2. Because annexin A2 is not a transmembrane protein, the mechanisms of APLA/anti-␤ 2 GPI Ab-mediated EC activation are uncertain, although a role for a TLR4/myeloid differentiation factor 88-dependent pathway leading to activation of NF-B has been proposed. In the present study, we confirm a critical role for TLR4 in anti-␤ 2 GPI Ab-mediated EC activation and demonstrate that signaling through TLR4 is mediated through the assembly of a multiprotein signaling complex on the EC surface that includes annexin A2, TLR4, calreticulin, and nucleolin. An essential role for each of these proteins in cell activation is suggested by the fact that inhibiting the expression of each using specific siRNAs blocked EC activation mediated by APLAs/anti-␤ 2 GPI Abs. These results provide new evidence for novel proteinprotein interactions on ECs that may contribute to EC activation and the pathogenesis of APLA/anti-␤ 2 GPI-associated thrombosis and suggest potential new targets for therapeutic intervention in antiphospholipid syndrome. (Blood. 2012; 119(3):884-893) IntroductionAntiphospholipid syndrome (APS) is characterized by thrombosis and recurrent fetal loss in patients with circulating antiphospholipid Abs (APLAs) and is the most important cause of acquired thrombophilia. [1][2][3] Prospective studies have demonstrated that patients with APS experience significant morbidity and mortality despite recommendations for indefinite anticoagulation. 4 The term "antiphospholipid" is actually a misnomer, because the majority of APLAs are directed against phospholipid-binding proteins, of which ␤ 2 -glycoprotein I (␤ 2 GPI) is the most common. 5,6 The clinical importance of anti-␤ 2 GPI Abs has been demonstrated in several previous reports, 7 and recent studies have shown that affinity-purified human anti-␤ 2 GPI Abs induce thrombosis in mice. 8 Despite the clinical importance of APS, however, its pathogenesis has not been well defined. 1,3,9 One mechanism by which APLAs/anti-␤ 2 GPI Abs may promote thrombosis is through ␤ 2 GPI-dependent activation of endothelial cells (ECs). [10][11][12] ECs play a critical role in the maintenance of blood fluidity through expression of anticoagulant proteins on their luminal surface and the elaboration of antithrombotic substances. 13 However, EC activation leads to loss of these anticoagulant properties and transformation to a pro-adhesive, procoagulant phenotype. 13 APLAs/anti-␤ 2 GPI Abs induce EC activation in vitro and in vivo, as determined by their ability to increase the expression of adhesion molecules (E-selectin, ICAM-1, VCAM-1), and tissue factor (TF) and to enhance the expression, synthesis, and/or secretion of pro-inflammatory cytokines and chemokines. 3,[10][11][12] These effects may account for the ab...

Heart failure caused by ischemic heart disease is a leading cause of death in the developed world. Treatment is currently centered on regimens involving G protein-coupled receptors (GPCRs) or nitric oxide (NO). These regimens are thought to target distinct molecular pathways. We showed that these pathways were interdependent and converged on the effector GRK2 (GPCR kinase 2) to regulate myocyte survival and function. Ischemic injury coupled to GPCR activation, including GPCR desensitization and myocyte loss, requires GRK2 activation, and we found that cardioprotection mediated by S-nitrosylation and inhibition of GRK2 depended on endothelial nitric oxide synthase (eNOS). Conversely, the cardioprotective effects of NO bioactivity were absent in a knock-in mouse with a form of GRK2 that cannot be S-nitrosylated. Because GRK2 and eNOS inhibit each other, the balance of the activities these enzymes in the myocardium determined the outcome to ischemic injury. Our findings suggest new insights into the mechanism of action of classic drugs used to treat heart failure and new therapeutic approaches to ischemic heart disease.

Anaerobic digestion (AD) technology is used commercially around the world, especially in Europe, which has set some challenging targets to diversify its energy mix with more renewable energy. This study intends to demonstrate, through technology prospecting, the relation between academic research (published articles) and technology development (patent applications) evolved from 1990 to 2015. Published articles were classified under the topics and wastes they cover, which include manure, agricultural and food waste, wastewater, sewage sludge and the organic fraction of municipal solid waste, with the last of these often being associated with co-digestion processes. Meanwhile, the patents in the area are mostly for equipment of the AD process and new methods or means of purifying the biogas obtained. It was found that the patents filed in Europe tend to protect their innovations only occasionally in countries outside the EU. Germany is the clear leader in all the areas of research and the commercial applications of the technologies, followed by Italy, Spain and Sweden. This study also demonstrates the immense potential of biogas throughout Europe, not just for energy generation, but also as a fuel and a by-product of the treatment of different kinds of waste.