Myostatin is a negative regulator of skeletal muscle size, previously shown to inhibit muscle cell differentiation. Myostatin requires both Smad2 and Smad3 downstream of the activin receptor II (ActRII)/activin receptor-like kinase (ALK) receptor complex. Other transforming growth factor-beta (TGF-beta)-like molecules can also block differentiation, including TGF-beta(1), growth differentiation factor 11 (GDF-11), activins, bone morphogenetic protein 2 (BMP-2) and BMP-7. Myostatin inhibits activation of the Akt/mammalian target of rapamycin (mTOR)/p70S6 protein synthesis pathway, which mediates both differentiation in myoblasts and hypertrophy in myotubes. Blockade of the Akt/mTOR pathway, using small interfering RNA to regulatory-associated protein of mTOR (RAPTOR), a component of TOR signaling complex 1 (TORC1), increases myostatin-induced phosphorylation of Smad2, establishing a myostatin signaling-amplification role for blockade of Akt. Blockade of RAPTOR also facilitates myostatin's inhibition of muscle differentiation. Inhibition of TORC2, via rapamycin-insensitive companion of mTOR (RICTOR), is sufficient to inhibit differentiation on its own. Furthermore, myostatin decreases the diameter of postdifferentiated myotubes. However, rather than causing upregulation of the E3 ubiquitin ligases muscle RING-finger 1 (MuRF1) and muscle atrophy F-box (MAFbx), previously shown to mediate skeletal muscle atrophy, myostatin decreases expression of these atrophy markers in differentiated myotubes, as well as other genes normally upregulated during differentiation. These findings demonstrate that myostatin signaling acts by blocking genes induced during differentiation, even in a myotube, as opposed to activating the distinct "atrophy program." In vivo, inhibition of myostatin increases muscle creatine kinase activity, coincident with an increase in muscle size, demonstrating that this in vitro differentiation measure is also upregulated in vivo.

Lethal necrotizing fasciitis caused by Streptococcus pyogenes is characterized by a paucity of neutrophils at the site of infection. Interleukin (IL)-8, which is important for neutrophil transmigration and activation, can be degraded by S. pyogenes. Blood isolates of S. pyogenes were better able to degrade human IL-8 than throat isolates. Degradation of IL-8 was the result of a single specific cleavage between 59glutamine and 60arginine within the IL-8 C-terminal alpha helix. Cleaved IL-8 reduced neutrophil activation and migration. IL-8-cleaving activity was found in partially purified supernatant of a necrotizing fasciitis isolate, and this activity was associated with an approximately 150-kDa fraction containing S. pyogenes cell envelope proteinase (SpyCEP). IL-8-cleaving activity corresponded with the presence of SpyCEP in the supernatant. Cleavage of IL-8 by S. pyogenes represents an unprecedented mechanism of immune evasion, effectively preventing IL-8 C-terminus-mediated endothelial translocation and subsequent recruitment of neutrophils.

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The natural-law theory on which we have been working during the past twenty-five years has stimulated many critical responses. We have restated the theory in various works, not always calling attention to developments. This paper reformulates some parts of the theory, taking into account the criticisms of which we are aware. We append an annotated, select bibliography.

T issues are exposed to hypoxia followed by reoxygenation during ischemia-reperfusion, which occurs in several clinical settings, including organ transplantation, percutaneous coronary intervention, and bypass grafting.1,2 Hypoxiareoxygenation promotes inflammation by activating nuclear factor κB (NF-κB) transcription factors, which induce adhesion proteins (eg, vascular cell adhesion moleucle-1 [VCAM-1], E-selectin) and other inflammatory molecules.3-9 NF-κB transcription factors are regulated by an intricate signaling network that governs their intracellular localization and transcriptional activity. 10 In the basal state, NF-κB dimers are inactivated by binding to inhibitor of κB (IκB) proteins, which sequester NF-κB in the cytoplasm by masking its nuclear localization sequence. IκB kinase promotes NF-κB activation by phosphorylating IκBα, a modification that targets it for ubiquitin-mediated degradation, and by phosphorylating RelA NF-κB subunits to enhance DNA binding and transcriptional activation. 11 In This Issue, see p 1521Editorial, see p 1526Recent studies have shed light on the signaling events that control NF-κB activation by hypoxia. In normoxic conditions, IκB kinase proteins are targeted for hydroxylation by prolyl hydroxylase domain 1, a modification that leads to their Rationale: Hypoxia followed by reoxygenation promotes inflammation by activating nuclear factor κB transcription factors in endothelial cells (ECs). This process involves modification of the signaling intermediary tumor necrosis factor receptor-associated factor 6 with polyubiquitin chains. Thus, cellular mechanisms that suppress tumor necrosis factor receptor-associated factor 6 ubiquitination are potential therapeutic targets to reduce inflammation in hypoxic tissues. Objective:In this study, we tested the hypothesis that endothelial activation in response to hypoxia-reoxygenation can be influenced by Cezanne, a deubiquitinating enzyme that cleaves ubiquitin from specific modified proteins. Methods and Results: Studies of cultured ECs demonstrated that hypoxia (1% oxygen) induced Cezanne viap38 mitogen-activated protein kinase-dependent transcriptional and post-transcriptional mechanisms. Hypoxiareoxygenation had minimal effects on proinflammatory signaling in unmanipulated ECs but significantly enhanced Lys63 polyubiquitination of tumor necrosis factor receptor-associated factor 6, activation of nuclear factor κB, and expression of inflammatory genes after silencing of Cezanne. Thus, although hypoxia primed cells for inflammatory activation, it simultaneously induced Cezanne, which impeded signaling to nuclear factor κB by suppressing tumor necrosis factor receptor-associated factor 6 ubiquitination. Similarly, ischemia induced Cezanne in the murine kidney in vascular ECs, glomerular ECs, podocytes, and epithelial cells, and genetic deletion of Cezanne enhanced renal inflammation and injury in murine kidneys exposed to ischemia followed by reperfusion. Conclusions:

To dissect the individual effects of the four non-MHC, autosomal loci (Bxs1 to Bxs4) that contribute to SLE susceptibility in BXSB mice, we generated congenic lines from chromosome 1 on a C57BL/10.YBXSB (B10.Yaa) background for the intervals (values in megabases (Mb)) Bxs1 (46.3-89.2 Mb), Bxs1/4 (20.0-65.9 Mb), Bxs1/2 (64.4-159.0 Mb), and Bxs2/3 (105.4-189.0 Mb). Glomerulonephritis, qualitatively similar to that seen in the parental BXSB strain, developed in three of these congenic strains. Early onset, severe disease was observed in B10.Yaa.BXSB-Bxs2/3 congenic mice and caused 50% mortality by 12 mo. In B10.Yaa.BXSB-Bxs1/4 mice disease progressed more slowly, resulting in 13% mortality at 12 mo. The progression of renal disease in both of these strains was correlated with the level of anti-dsDNA Abs. B10.Yaa.BXSB-Bxs1 mice, despite their genetic similarity to B10.Yaa.BXSB-Bxs1/4 mice, developed a low-grade glomerulonephritis in the absence of anti-dsDNA Abs. Thus, Bxs4 directed an increase in titer and spectrum of autoantibodies, whereas Bxs1 promoted the development of nephritis. The Bxs2 interval was linked to the production of anti-dsDNA Abs without concomitant glomerulonephritis. In contrast, the Bxs3 interval was sufficient to generate classic lupus nephritis in a nonautoimmune–prone strain. Immune phenotype differed between controls and congenics with a significant increase in B220+ cells in BXSB and B10.Yaa.BXSB-Bxs2/3, and an increase in CD4 to CD8 ratio in both BXSB and B10.Yaa.BXSB-Bxs1/4. Disease in the Bxs3 mice was delayed in comparison to the BXSB parental strain, emphasizing the necessity for multiple interactions in the production of the full BXSB phenotype.

Objective-Atherosclerosis is a focal disease that occurs predominantly at branches and bends of the arterial tree.Endothelial cells (EC) at atherosusceptible sites are prone to injury, which can contribute to lesion formation, whereas EC at atheroprotected sites are resistant. The c-Jun N-terminal kinase (JNK) is activated constitutively in EC at atherosusceptible sites but is inactivated at atheroprotected sites by mitogen-activated protein kinase phosphatase-1 (MKP-1). Here, we examined the effects of JNK activation on EC physiology at atherosusceptible sites. Methods and Results-We identified transcriptional programs regulated by JNK by applying a specific pharmacological inhibitor to cultured EC and assessing the transcriptome using microarrays. This approach and subsequent validation by gene silencing revealed that JNK positively regulates the expression of numerous proapoptotic molecules. Analysis of aortae of wild-type, JNK1Ϫ/Ϫ, and MKP-1 Ϫ/Ϫ mice revealed that EC at an atherosusceptible site express proapoptotic proteins and are primed for apoptosis and proliferation in response to lipopolysaccharide through a JNK1-dependent mechanism, whereas EC at a protected site expressed lower levels of proapoptotic molecules and were protected from injury by MKP-1. Key Words: apoptosis Ⅲ arterial endothelium Ⅲ atherosusceptibility Ⅲ c-Jun N-terminal kinase Ⅲ mitogen-activated protein kinase phosphatase-1 A therosclerosis is characterized by the accumulation of cells, lipids, and extracellular matrix in the wall of an artery, which can result in occlusion of the vessel lumen. It develops predominantly at branches and bends that are exposed to disturbed patterns of blood flow, whereas regions exposed to uniform flow are protected. [1][2][3][4] The molecular mechanism underlying the distinct spatial distribution of lesions is likely to involve apoptosis. Regions that are predisposed to atherosclerosis are characterized by relatively high rates of endothelial cell (EC) injury and turnover, [5][6][7] and apoptosis can be induced in cultured EC by the application of atheroprone flow patterns. 8,9 A causal relationship between apoptosis and atherosclerosis was established by enforcing expression of a proapoptotic molecule in arterial EC, which enhanced the accessibility of lipoproteins and leukocytes to arteries and initiated lesion formation in hypercholesterolemic mice. 10 In addition, focal endothelial apoptosis/injury in atherosclerotic lesions can, in turn, lead to endothelial denudation and exposure of a procoagulant vascular wall, a major cause of coronary thrombosis. 11,12 Several proatherogenic agents are known to induce EC apoptosis, including oxidized low-density lipoproteins, 13 reactive oxygen intermediaries (eg, H 2 O 2 14 ) and proinflammatory mediators (eg, lipopolysaccharide [LPS], 15 tumor necrosis factor [TNF]-␣ 16 ) by activating distinct signaling pathways that converge to cleave procaspase-3 into the active form of caspase-3. Cleaved caspase-3, in turn, executes apoptosis by activating numerous downs...

The use of terminal sedation to control the intense discomfort of dying patients appears both to be an established practice in palliative care and to run counter to the moral and legal norm that forbids health care professionals from intentionally killing patients. This raises the worry that the requirements of established palliative care are incompatible with moral and legal opposition to euthanasia. This paper explains how the doctrine of double effect can be relied on to distinguish terminal sedation from euthanasia. The doctrine of double effect is rooted in Catholic moral casuistry, but its application in law and morality need not depend on the particular framework in which it was developed. The paper further explains how the moral weight of the distinction between intended harms and merely foreseen harms in the doctrine of double effect can be justified by appeal to a limitation on the human capacity to pursue good.