Macrophages and angiogenesis

Macrophages are supposed to play a key role in inflammatory and tumor angiogenesis. Their importance derives from (1) their ubiquitous presence in normal and especially inflamed tissues, (2) their potential to become activated in response to appropriate stimuli, and (3) their repertoire of secretory products. By release of proteases, growth factors (bFGF, GM-CSF, TGF-alpha, IGF-I, PDGF, VEGF/VPF, TGF-beta), and other monokines (IL-1, IL-6, IL-8, TNF-alpha, substance P, prostaglandins, interferons, thrombospondin 1), activated macrophages have the capability to influence each phase of the angiogenic process, such as alterations of the local extracellular matrix, induction of endothelial cells to migrate or proliferate, and inhibition of vascular growth with formation of differentiated capillaries. This review describes macrophage physiology and the influence of macrophage secretory products on the different phases of angiogenesis in vitro and in vivo.

Proopiomelanocortin-derived peptides are synthesized and released by human keratinocytes

Proopiomelanocortin (POMC), the precursor for melanotropic, corticotropic, and opioid peptides such as alpha-melanocyte-stimulating hormone (alpha MSH), ACTH, and other related peptides, was originally identified as a product of the pituitary gland. However, recent evidence shows that POMC products can also be produced by nonpituitary tissues. Because keratinocytes, the major constituent of the epidermis exhibit the capacity to release a variety of proinflammatory and immunomodulatory mediators, the present study was performed to investigate whether human keratinocytes are able to produce POMC-derived peptides. Supernatants of human normal keratinocytes and an epidermal carcinoma cell line (A431) contained significant levels of immunoreactive alpha MSH and ACTH. Upon immuneprecipitation and size-exclusion chromatography, keratinocyte-derived alpha MSH exhibited a molecular mass of approximately 1 kD and was biologically active as demonstrated in a tyrosinase bioassay. Northern blot analysis revealed the expression of POMC-specific transcripts (1.3 kb) in both normal keratinocytes and A431 cells. The production of alpha MSH and ACTH could be significantly upregulated both at the protein and mRNA level upon treatment with phorbol myristate acetate, ultraviolet light, or interleukin 1. These data provide first evidence that human keratinocytes produce POMC-derived peptides such as alpha MSH and ACTH. Because POMC-derived peptides recently have been recognized as potent immunomodulatory mediators, their presence in the epidermis may have a major impact on the skin immune system.

Ultraviolet-B-induced apoptosis of keratinocytes: evidence for partial involvement of tumor necrosis factor-alpha in the formation of sunburn cells

Irradiation with ultraviolet (UV) B radiation results in the formation of apoptotic keratinocytes called sunburn cells. Recently, it was demonstrated that keratinocytes can release tumor necrosis factor-alpha (TNF-alpha), which is known to cause apoptosis in particular cells. In addition, it has been shown that UVB light induces the release of TNF-alpha by keratinocytes and that keratinocytes express the 55-kD receptor for TNF-alpha. Therefore, we investigated whether TNF-alpha is involved in UV-induced apoptosis of keratinocytes. Normal human keratinocytes and HaCaT cells were exposed to UVB light, and apoptosis was examined by nick translation evaluated by fluorescence-activated cell sorter analysis. UVB induced apoptosis in a dose-dependent manner, which was confirmed by electron microscopy. Addition of a polyclonal antibody directed against human TNF-alpha immediately after UVB exposure was able to reduce DNA fragmentation. However, it was not possible to rescue all cells from apoptosis. To prove whether TNF-alpha is also involved in vivo in UVB-induced apoptosis of keratinocytes, Balb/c mice were exposed to UVB on their abdomens, skin biopsies were performed 24 h later, and sunburn cells were counted. A single dose of 2000 J/m2 caused a significant induction of sunburn cells. Subcutaneous injection of a polyclonal antibody directed against murine TNF-alpha immediately after UVB treatment resulted in a significant but incomplete reduction of sunburn cells, whereas injection of a rabbit IgG as a control had no effect. In both the in vitro and in vivo systems, application of recombinant TNF-alpha alone either to untreated keratinocytes or into normal murine skin did not induce sunburn cells. Thus, these data demonstrate that TNF-alpha is involved in UVB-induced apoptosis, but by itself is not able to induce sunburn cells. This further supports the notion that UVB-induced apoptosis of keratinocytes is a multifactorial event.

Macrophage-derived angiogenesis factors

A majority of angiogenic factors has been shown to be produced by macrophages. This review will give a concise description of their biochemical nature, their isolation from macrophages and their angiogenic activity. Among the factors with mitogenic effects on endothelial cells are basic fibroblast growth factor (bFGF), transforming growth factor-alpha (TGF-alpha) and very probably insulin-like growth factor-1 (IGF-1). Other secretory products such as angiotropin and human angiogenic factor (HAF) are nonmitogenic but promote angiogenesis by inducing migration of endothelial cells. Prostaglandins, platelet-derived growth factor (PDGF), granulocyte-macrophage- and granulocyte-colony stimulating factor (GM-CSF, G-CSF), interleukin 6 (IL-6) and angiotensin converting enzyme (ACE) have also been shown to be angiogenic, but their mode of action is still to be clearly defined. As the extracellular matrix appears to be involved in the control of angiogenesis, macrophage-derived factors that can alter this structure via degradation or via the clotting system will also be discussed. Tumor necrosis factor alpha (TNF-alpha), interleukin 1 (IL-1) and transforming growth factor-beta (TGF-beta) have complex actions on endothelial cells, and can partially inhibit angiogenesis. Among the factors which solely inhibit neovascularization are the interferons. As it is not known whether all of these factors play a role in angiogenesis in vivo attempts to detect them in situ during the course of neovascularization will be described. Finally macrophages will be discussed as cells that may not be mandatory for each phase of the angiogenic process but whose angiogenic capabilities are comprehensive and unsurpassed by any other cell.

Chylous Ascites: A Review of Pathogenesis, Diagnosis and Treatment

Chylous ascites (CA) is a rare form of ascites that results from the leakage of lipid-rich lymph into the peritoneal cavity. This usually occurs due to trauma and rupture of the lymphatics or increased peritoneal lymphatic pressure secondary to obstruction. The underlying etiologies for CA have been classified as traumatic, congenital, infectious, neoplastic, postoperative, cirrhotic or cardiogenic. Since malignancy and cirrhosis account for about two-thirds of all the cases of CA in Western countries, in this article we have attempted to reclassify CA based on portal and non-portal etiologies. The diagnosis of CA is based on the distinct characteristic of the ascitic fluid which includes a milky appearance and a triglyceride level of >200 mg/dL. The management consists of identifying and treating the underlying disease process, dietary modification, and diuretics. Some studies have also supported the use of agents such as orlistat, somatostatin, octreotide and etilefrine. Paracentesis and surgical interventions in the form of transjugular intrahepatic portosystemic shunt (commonly known as TIPS), peritoneal shunt, angiography with embolization of a leaking vessel, and laparotomy remain as treatment options for cases refractory to medical management.

Controlled-release delivery system for the alpha-MSH analog melanotan-I using poloxamer 407

The overall objective of these studies was to develop a controlled-release formulation of Melanotan-I (MT-I) containing poloxamer 407 (P407). Various aqueous formulations were evaluated containing MT-I and 25% w/v P407 alone, or with one of the following additives present, i.e., poly(vinylpyrrolidone) 10000 (PVP), methylcellulose (MC), or hydroxypropyl methylcellulose (HPMC). The in-vitro release profiles of MT-I from the P407 formulations and the dissolution of the gel were obtained simultaneously using a membraneless in-vitro model. These data were obtained at 37 degrees C and room temperature (24 degrees C). It was observed that the PVP-containing P407 formulations of MT-I accelerated the dissolution of gel and the release of the peptide compared to the control formulation. The formulations containing MC or HPMC exhibited the slowest dissolution rates and release of MT-I. The same rank order was observed for the dissolution and release profiles of MT-I from the various formulations at both temperatures. The in-vivo release kinetics of selected formulations were analyzed in guinea pigs following intraperitoneal administration. The plasma concentration-time profiles showed an extended release of the peptide formulated with gel compared to the intraperitoneal administration of MT-I in solution. On the basis of the in-vitro and in-vivo results, the P407 formulations of MT-I with MC or HPMC as an additive showed potential for use as a controlled-release delivery system for MT-I.

Extraction and validation of a new set of CMS pythia8 tunes from underlying-event measurements

New sets of CMS underlying-event parameters ("tunes") are presented for the pythia8 event generator. These tunes use the NNPDF3.1 parton distribution functions (PDFs) at leading (LO), next-to-leading (NLO), or next-to-next-to-leading (NNLO) orders in perturbative quantum chromodynamics, and the strong coupling evolution at LO or NLO. Measurements of charged-particle multiplicity and transverse momentum densities at various hadron collision energies are fit simultaneously to determine the parameters of the tunes. Comparisons of the predictions of the new tunes are provided for observables sensitive to the event shapes at LEP, global underlying event, soft multiparton interactions, and double-parton scattering contributions. In addition, comparisons are made for observables measured in various specific processes, such as multijet, Drell-Yan, and top quark-antiquark pair production including jet substructure observables. The simulation of the underlying event provided by the new tunes is interfaced to a higher-order matrix-element calculation. For the first time, predictions from pythia8 obtained with tunes based on NLO or NNLO PDFs are shown to reliably describe minimum-bias and underlying-event data with a similar level of agreement to predictions from tunes using LO PDF sets.

Delivery of siRNA in vitro and in vivo using PEI-capped porous silicon nanoparticles to silence MRP1 and inhibit proliferation in glioblastoma

BACKGROUND

Multidrug resistance-associated protein 1 (MRP1) overexpression plays a major role in chemoresistance in glioblastoma multiforme (GBM) contributing to its notorious deadly nature. Although MRP1-siRNA transfection to GBM in vitro has been shown to sensitise the cells to drug, MRP1 silencing in vivo and the phenotypic influence on the tumour and normal tissues upon MRP1 down-regulation have not been established. Here, porous silicon nanoparticles (pSiNPs) that enable high-capacity loading and delivery of siRNA are applied in vitro and in vivo.

RESULT

We established pSiNPs with polyethyleneimine (PEI) capping that enables high-capacity loading of siRNA (92 µg of siRNA/mg PEI-pSiNPs), and optimised release profile (70% released between 24 and 48 h). These pSiNPs are biocompatible, and demonstrate cellular uptake and effective knockdown of MRP1 expression in GBM by 30%. Also, siRNA delivery was found to significantly reduce GBM proliferation as an associated effect. This effect is likely mediated by the attenuation of MRP1 transmembrane transport, followed by cell cycle arrest. MRP1 silencing in GBM tumour using MRP1-siRNA loaded pSiNPs was demonstrated in mice (82% reduction at the protein level 48 h post-injection), and it also produced antiproliferative effect in GBM by reducing the population of proliferative cells. These results indicate that in vitro observations are translatable in vivo. No histopathological signs of acute damage were observed in other MRP1-expressing organs despite collateral downregulations.

CONCLUSIONS

This study proposes the potential of efficient MRP1-siRNA delivery by using PEI-capped pSiNPs in achieving a dual therapeutic role of directly attenuating the growth of GBM while sensitising residual tumour cells to the effects of chemotherapy post-resection.

Endothelium-derived relaxing factor and the effects of acetylcholine and histamine on resistance blood vessels

1. The role of endothelium-derived relaxing factor (EDRF) in the action of vasodilator (acetylcholine, histamine, nitroprusside) and vasoconstrictor (noradrenaline, vasopressin) drugs on vascular resistance in the isolated perfused kidney and mesentery of the rat was studied. 2. Acetylcholine (EC50 = 0.18 +/- 0.05 nmol and 3.1 +/- 0.06 nmol, n = 8) and histamine (EC50 = 31.2 +/- 4.9 nmol and 46.2 +/- 3.9 nmol, n = 8) produced dose-related vasodilatation in noradrenaline-preconstricted (i.e. 'high tone') rat renal and mesenteric blood vessels. The response to both vasodilators (but not nitroprusside) was abolished by infusion of CHAPS (4.7 mg ml-1, 30 s). By use of an immunocytochemical staining procedure CHAPS was demonstrated to remove vascular endothelial cells lining intrarenal blood vessels. 3. Gossypol (3 microM), metyrapone (10 microM) and nordihydroguaiaretic acid, (NDGA, 30 microM), presumed inhibitors of EDRF biosynthesis, reduced or abolished the response to acetylcholine and histamine in perfused kidney and mesentery of the rat without affecting vasodilatation due to nitroprusside. Mepacrine (10 microM) similarly abolished the response to acetylcholine and histamine but in addition, reduced the response to nitroprusside in both preparations. 4. Methylene blue (100 microM), a presumed antagonist of the effect of EDRF, abolished vasodilatation due to acetylcholine and histamine and reduced the response to nitroprusside in perfused rat kidney and mesentery. Superoxide dismutase, SOD (15 u ml-1), was without effect. 5. While CHAPS treatment significantly augmented the vasoconstrictor response to both noradrenaline and vasopressin in perfused renal and mesenteric vessels this effect was not mimicked by metyrapone or gossypol suggesting that the enhanced effect of vasopressor agents in CHAPSperfused rat organs is due to the removal of a permeability barrier rather than impaired EDRF formation. 6. Responses to vasoconstrictor and vasodilator drugs in the perfused kidney and mesentery were obtained in the presence of indomethacin (8 microM) which produced in excess of 90% inhibition of prostacyclin (PGI2) release as measured by radioimmunoassay of 6-oxo-prostaglandin F1 alpha,. (6-oxo- PGF1 alpha) in the Krebs effluent. 7. We provide evidence that EDRF mediates the vasodilator response to acetylcholine and histamine in resistance blood vessels in perfused rat kidney and mesentery. The possibility that EDRF has a physiological role to play in regulating the calibre of resistance blood vessels is discussed.

Palliative therapy of colorectal carcinoma: stent or surgery?

"Surgical" palliation of obstructing colorectal carcinomas may involve resection with or without stoma formation, formation of a stoma alone, a colonic bypass procedure, or no procedure at all. Palliative surgical procedures confer a significant morbidity and mortality. Factors associated with increased mortality for colorectal cancer include advancing age of patient, advancing stage of the disease and the necessity for an emergency procedure. Advanced obstructing malignant lesions pose a clinical dilemma as the risks and time of recovery from surgery have to be balanced against providing a dignified quality of remaining life. Self expanding metal stents (SEMS) for acutely obstructing advanced colorectal carcinomas provide a cost effective option that avoids surgery in a usually frail group of patients. They can be inserted under sedation, rapidly decompress the colon and lead to an early return of colonic function. The procedure is carried out endoscopically with radiological assistance to determine a lumen and to confirm adequate stent placement. SEMS are not suitable for low rectal lesions and are more difficult to place in those that traverse colonic flexures. Complications from successful SEMS placement include migration and stent occlusion. The morbidity associated with SEMS is associated with migration or perforation of the colon during placement, pain and less commonly haemorrhage. Despite these problems most patients can be successfully decompressed without further endoscopic or surgical reintervention and allow satisfactory palliation.

Structural and electronic investigation of ZnO nanostructures synthesized under different environments

An explicit study of comparison on the basis of structure and electronic properties of ZnO nanostructures was discussed. ZnO synthesized by sol-gel and hydrothermal method without using any surfactant leads to the formation of two different morphologies. Rietveld crystal structure refinement of X-ray diffraction patterns confirmed the wurtzite structure of both samples. Raman spectra also confirmed the wurtzite phase formation and improved crystallinity in sample synthesized by hydrothermal route that are concurrent with results obtained from X-ray diffraction. Field-emission scanning electron microscopy revealed the formation of ZnO spherical nanoparticle structure for sol-gel method and flower like μ-structure for ZnO prepared through hydrothermal route. Williamson-Hall equations applied to study the strain and stress parameters present in the material, show the decrease in their values as the crystal size increases. Energy band gap is calculated using diffused reflectance spectroscopy. Near-edge X-ray absorption fine-structure measurements at O K- and Zn L_3,2- edges simulated with FEFF9.05 code confirmed the presence of oxygen vacancies. Further extended x-ray absorption fine-structure revealed a similar local atomic structure for both samples despite having different morphologies.

Increased vasodilator response to acetylcholine of renal blood vessels from diabetic rats

The vasodilator effect of acetylcholine (ACh) and nitroprusside and the vasoconstrictor effect of noradrenaline was assessed in the perfused kidney of streptozocin diabetic rats. Compared with control animals injected with acidified saline, the renal vasoconstrictor effect of noradrenaline was increased in diabetic rats both in terms of the dose required to produce 50% of the maximal effect (EC50) and in the maximal response achieved. The renal vasodilator effect of ACh (but not nitroprusside) was similarly enhanced in diabetic animals. The effect of ACh (but not nitroprusside) in the perfused kidney of both control and diabetic rats was reduced or abolished by mepacrine (10 microM), metyrapone (10 microM) or methylene blue (100 microM) suggesting that ACh exhibits vasodilator activity in the rat kidney by virtue of releasing endothelium derived relaxing factor (EDRF). These results are in contrast to previous published reports demonstrating reduced biosynthesis of EDRF in the aorta of diabetic rats. The mechanism which underlies the increased renal vascular response to ACh is not known. However, increased endothelial cell turnover or cholinoceptor number, elevated activity of enzyme(s) which synthesis EDRF or hyperresponsiveness of vascular smooth muscle to released EDRF should all be considered.

Endothelium-derived relaxing factor inhibits platelet aggregation in human whole blood in vitro and in the rat in vivo

Carbachol (0.03-10 microM) or histamine (0.06-10 microM) challenge of indomethacin-pretreated rat aortic rings inhibited ADP-induced aggregation of platelets suspended in anticoagulated human whole blood. The maximum inhibition of platelet aggregation achieved with either drug was approximately 50%. No such inhibition was observed in rat aortic rings rubbed to remove endothelial cells or in intact vessels preincubated with nordihydroguaiaretic acid (NDGA, 10 microM), mepacrine (10 microM) or methylene blue (100 microM). Intravenously (i.v.) injected carbachol (0.5-5 micrograms/kg) also inhibited ADP-induced accumulation of 111indium-labelled platelets in the pulmonary circulation of urethane-anaesthetised rats. This effect of carbachol was inhibited by i.v. injected methylene blue (10 mg/kg) but unaffected by indomethacin (3 mg/kg) or hexamethonium (10 mg/kg) suggesting that PGI2 or adrenaline release did not account for the inhibition of platelet activation observed. Similarly, the platelet inhibitory effect of carbachol in vivo was not related to increased pulmonary vascular blood flow (assessed by accumulation of 111indium-labelled erythrocytes) or blood fibrinolytic activity (measured by euglobulin clot bioassay). The present results suggest that endothelium-derived relaxing factor or a like substance inhibits human platelet aggregation in vitro and rat platelet aggregation in vivo.

Neuromyogenic properties of the internal anal sphincter: therapeutic rationale for anal fissures

Lateral sphincterotomy diminishes internal anal sphincter hypertonia and thereby reduces anal canal pressure. This improves anal mucosal blood flow and promotes the healing of anal fissures. However, sphincterotomy can be associated with long term disturbances of sphincter function. The optimal treatment for an anal fissure is to induce a temporary reduction of anal canal resting pressure to allow healing of the fissure without permanently disrupting normal sphincter function. Broader understanding of the intrinsic mechanisms controlling smooth muscle contraction has allowed pharmacological manipulation of anal sphincter tone. We performed an initial Medline literature search to identify all articles concerning "internal anal sphincter" and "anal fissures". This review is based on these articles and on additional publications obtained by manual cross referencing. Internal anal smooth muscle relaxation can be inhibited by stimulation of non-adrenergic non-cholinergic enteric neurones, parasympathetic muscarinic receptors, or sympathetic beta adrenoceptors, and by inhibition of calcium entry into the cell. Sphincter contraction depends on an increase in cytoplasmic calcium and is enhanced by sympathetic adrenergic stimulation. Currently, the most commonly used pharmacological agent in the treatment of anal fissures is topical glyceryl trinitrate, a nitric oxide donor. Alternative agents that exhibit a similar effect via membrane Ca2+ channels, muscarinic receptors, and alpha or beta adrenoceptors are also likely to have a therapeutic potential in treating anal fissures.

The effect of arginine and nitric oxide on resistance blood vessels of the perfused rat kidney

1. The vasodilator effects of arginine, nitric oxide (NO), acetylcholine (ACh) and sodium nitroprusside (NP) in the noradrenaline-preconstricted ('high tone') perfused rat kidney have been examined. 2. L-Arginine (0.6-23 mumol) caused a biphasic change in renal perfusion pressure. D-Arginine (0.6-23 mumol) was without effect. The second vasodilator component was abolished and the first vasoconstrictor effect augmented following CHAPS-induced removal of the vascular endothelium suggesting that vasodilatation was endothelium-dependent. 3. L-Arginine salts produced transient and dose-related vasodilatation. L-Arginine methylester was the most potent with an ED50 of 2.2 +/- 0.4 mumol (n = 6). The rank order of potency of the salts tested was: methylester greater than hydroxamate greater than chloride. L-Homoarginine chloride was also vasodilator (ED50, 12.0 +/- 1.3 mumol, n = 5). D-Arginine chloride was without effect at doses up to 170 mumol. Responses to L-arginine chloride were endothelium-derived relaxing factor (EDRF)-dependent being abolished by CHAPS (4.7 mg ml-1, 30 s) and significantly inhibited (greater than 70%) by gossypol (3 microM) and nordihydroguaiaretic acid (NDGA, 10 microM). 4. Vasodilatation due to NO was unaffected by CHAPS and gossypol treatment but inhibited by NDGA. NO was approximately 3 times less potent than ACh but 3000 times more potent than L-arginine methylester. 5. Kidneys perfused for 1 h with Krebs solution containing L-arginine chloride (100 microM) or L-canavanine (50 microM) showed no change in sensitivity towards ACh or NP. Higher concentrations of L-arginine chloride (500 microM) or L-canavanine (150 microM) significantly reduced the response to both vasodilators 6. L-Arginine salts dilate resistance blood vessels of the perfused rat kidney by a mechanism which may involve the release of EDRF from vascular endothelial cells of the perfused rat kidney..

Modelling cortical cataractogenesis 22: is in vitro reduction of damage in model diabetic rat cataract by taurine due to its antioxidant activity?

The protective effect of taurine in model in vitro diabetic cataract and the mechanism of this effect were investigated in isolated rat lenses. Isolated rat lenses were incubated in medium 199 in elevated glucose (55.6 m m) with taurine (5 m m). Taurine concentrations in the lenses were determined by amino acid analysis. Accumulative leakage of the intracellular enzyme lactate dehydrogenase (LDH) was used to estimate damage to the lens, as previously reported. In the clear lenses, prior to vacuole formation, after 1 or 2 days of incubation, the taurine and amino acids in lenses decreased progressively in concentration. In lenses incubated with 5 m m taurine, the level of taurine was increased towards that of control lenses. In taurine-treated lenses LDH leakage was significantly decreased, and lens clarity was maintained, similarly to that found previously for vitamin C and lipoic acid. To test whether taurine has similar antioxidant activity, we tested its ability to decrease luminol luminescence generated by (1) superoxide from hypoxanthine/xanthine oxidase and (2) peroxide from diluted glucose/glucose oxidase. For either superoxide or peroxide, the luminescence was decreased to zero, as a function of increasing taurine concentration, at 30 m m, approximately the physiological concentration of taurine in the lens. Spin trapping confirmed that taurine scavenged superoxide. This is consistent with a role for taurine as an important antioxidant protecting the lens against oxidative insults. Amino acids also had antioxidant activity in this assay, and as a group, when all activities were summed, their loss also contributed significantly to the antioxidant loss. Taken in conjunction with Wolff and Crabbe's observation of increased free radical generation by glucose auto-oxidation in diabetes, this suggests a push-pull mechanism for increased oxidative stress in diabetic cataract, involving both increased free radicals and decreased radical scavenging antioxidants.

Heterodimers of the calcium-binding proteins MRP8 and MRP14 are expressed on the surface of human monocytes upon adherence to fibronectin and collagen. Relation to TNF-alpha, IL-6, and superoxide production

The 27E10 antigen is a heterodimer of MRP8 and MRP14, two Ca(2+)-binding proteins related to the S-100 protein family. Previous studies have shown that 27E10 epitope-bearing monocyte subsets are prevalent in early acute but absent in chronic inflammatory conditions. These observations further provide an impetus for identifying the cellular mechanisms responsible for the appearance of different monocyte subpopulations during inflammation. Therefore this in vitro study was carried out to investigate the influence of adhesion in inducing 27E10-positive subsets. In adhesion assays the role of 27E10 antigen in spontaneous adherence was obvious, as a monoclonal antibody directed against the 27E10 antigen significantly inhibited the adherence of monocytes to collagen and fibronectin. In contrast, these extracellular matrix (ECM) proteins induce the cell surface expression and association of 27E10 antigen with cytoskeleton (CSK), detected by flow cytometry and confocal laser scan microscopy, respectively. Similar results were obtained on cross-linking with specific antibodies, thus showing involvement of the integrin molecules VLA-2 and VLA-4. In addition, the association with CSK could be confirmed by differential detergent extraction. The observed redistribution of 27E10 antigen guided by collagen compared with fibronectin was also paralleled by an augmented release of inflammatory cytokines interleukin-6, tumor necrosis factor alpha, and superoxide anions. Thus, this study demonstrates that under inflammatory conditions the interactions of extravasating monocytes with the ECM may induce an activated phenotype of monocytes marked by 27E10.

ORAI1 channel gating and selectivity is differentially altered by natural mutations in the first or third transmembrane domain

KEY POINTS

Gain-of-function mutations in the highly selective Ca²⁺ channel ORAI1 cause tubular aggregate myopathy (TAM) characterized by muscular pain, weakness and cramping. TAM-associated mutations in ORAI1 first and third transmembrane domain facilitate channel opening by STIM1, causing constitutive Ca²⁺ influx and increasing the currents evoked by Ca²⁺ store depletion. Mutation V107M additionally decreases the channel selectivity for Ca²⁺ ions and its inhibition by acidic pH, while mutation T184M does not alter the channel sensitivity to pH or to reactive oxygen species. The ORAI blocker GSK-7975A prevents the constitutive activity of TAM-associated channels and might be used in therapy for patients suffering from TAM.

ABSTRACT

Skeletal muscle differentiation relies on store-operated Ca²⁺ entry (SOCE) mediated by STIM proteins linking the depletion of endoplasmic/sarcoplasmic reticulum Ca²⁺ stores to the activation of membrane Ca²⁺ -permeable ORAI channels. Gain-of-function mutations in STIM1 or ORAI1 isoforms cause tubular aggregate myopathy (TAM), a skeletal muscle disorder with muscular pain, weakness and cramping. Here, we characterize two overactive ORAI1 mutants from patients with TAM: V107M and T184M, located in the first and third transmembrane domain of the channel. When ectopically expressed in HEK-293T cells or human primary myoblasts, the mutated channels increased basal and store-operated Ca²⁺ entry. The constitutive activity of V107M, L138F, T184M and P245L mutants was prevented by low concentrations of GSK-7975A while the G98S mutant was resistant to inhibition. Electrophysiological recordings confirmed ORAI1-V107M constitutive activity and revealed larger STIM1-gated V107M- and T184M-mediated currents with conserved fast and slow Ca²⁺ -dependent inactivation. Mutation V107M altered the channel selectivity for Ca²⁺ ions and conferred resistance to acidic inhibition. Ca²⁺ imaging and molecular dynamics simulations showed a preserved sensitivity of T184M to the negative regulation by reactive oxygen species. Both mutants were able to mediate SOCE in Stim1^-/- /Stim2^-/- mouse embryonic fibroblasts expressing the binding-deficient STIM1-F394H mutant, indicating a higher sensitivity for STIM1-mediated gating, with ORAI1-T184M gain-of-function being strictly dependent on STIM1. These findings provide new insights into the permeation and regulatory properties of ORAI1 mutants that might translate into therapies against diseases with gain-of-function mutations in ORAI1.

Observation of tt[over ¯]H Production

The observation of Higgs boson production in association with a top quark-antiquark pair is reported, based on a combined analysis of proton-proton collision data at center-of-mass energies of sqrt[s]=7, 8, and 13 TeV, corresponding to integrated luminosities of up to 5.1, 19.7, and 35.9  fb^{-1}, respectively. The data were collected with the CMS detector at the CERN LHC. The results of statistically independent searches for Higgs bosons produced in conjunction with a top quark-antiquark pair and decaying to pairs of W bosons, Z bosons, photons, τ leptons, or bottom quark jets are combined to maximize sensitivity. An excess of events is observed, with a significance of 5.2 standard deviations, over the expectation from the background-only hypothesis. The corresponding expected significance from the standard model for a Higgs boson mass of 125.09 GeV is 4.2 standard deviations. The combined best fit signal strength normalized to the standard model prediction is 1.26_{-0.26}^{+0.31}.

A comparative study on the effects of tumor necrosis factor-alpha (TNF-alpha), human angiogenic factor (h-AF) and basic fibroblast growth factor (bFGF) on the chorioallantoic membrane of the chick embryo

The chorioallantoic membrane (CAM) assay is a widely used bioassay for testing angiogenic activities. In the present study we compared the gross and micromorphological effects of three angiogenic factors applied in Elvax carriers on the CAM: Tumor necrosis factor-alpha (TNF-alpha), human angiogenic factor (h-AF), and basic fibroblast growth factor (bFGF). Our question was whether the CAM responds to these factors which have very different actions with a stereotype or with a factor specific reaction. By microangiography and light microscopy, all positive reactions appeared as a spoke-wheel vascular pattern with a bundle of small capillary blood vessels in the center. These vessels were predominantly of a distended type in h-AF and TNF experiments, while narrower capillary vessels followed bFGF application. Chorioallantoic ectoderm and endoderm were thickened by cell accumulation and the mesenchymal stroma of the CAM was edematous and infiltrated with leucocytes in all three reactions. Additionally, bFGF experiments showed areas of densely arranged fibroblasts. Observations in vivo showed chorioallantoic tissue movements as a possible mechanism for the spokewheel vascular pattern. As compared with our results from studies of cytokinetics with bromodeoxyuridine, these current findings indicate that chemotaxis is responsible for the chorioallantoic angiogenic reaction rather than cellular proliferation.