Local microvascular leakage promotes trafficking of activated neutrophils to remote organs.

Increased microvascular permeability to plasma proteins and neutrophil emigration are hallmarks of innate immunity and key features of numerous inflammatory disorders. Although neutrophils can promote microvascular leakage, the impact of vascular permeability on neutrophil trafficking is unknown. Here, through the application of confocal intravital microscopy, we report that vascular permeability-enhancing stimuli caused a significant frequency of neutrophil reverse transendothelial cell migration (rTEM). Furthermore, mice with a selective defect in microvascular permeability enhancement (VEC-Y685F-ki) showed reduced incidence of neutrophil rTEM. Mechanistically, elevated vascular leakage promoted movement of interstitial chemokines into the bloodstream, a response that supported abluminal-to-luminal neutrophil TEM. Through development of an in vivo cell labeling method we provide direct evidence for the systemic dissemination of rTEM neutrophils, and showed them to exhibit an activated phenotype and be capable of trafficking to the lungs where their presence was aligned with regions of vascular injury. Collectively, we demonstrate that increased microvascular leakage reverses the localization of directional cues across venular walls, thus causing neutrophils engaged in diapedesis to reenter the systemic circulation. This cascade of events offers a mechanism to explain how local tissue inflammation and vascular permeability can induce downstream pathological effects in remote organs, most notably in the lungs

Total body topical 5-fluorouracil for extensive non-melanoma skin cancer

Background Topical 5-fluorouracil 5% cream is one of the treatment modalities for non-melanoma skin cancer (NMSC). There is a lack of suitable therapies to treat patients with extensive NMSC. In this paper we report two patients with extensive NMSC treated by total body application of topical 5-fluorouracil 5% cream. Observations Topical 5-fluorouracil 5% cream was applied twice daily to the total body, including normal appearing skin. During the treatment, weekly blood samples were taken for measurement of 5-fluorouracil levels. All samples showed a 5-fluorouracil level less than the detection level of 10 mu g/l. Total body 5-fluorouracil 5% cream was shown to be an effective treatment in our patients; the majority of lesions cleared in both patients. Conclusions In conclusion, total body topical 5-fluorouracil 5% cream application was successful in two patients with extensive NMSC. No detectable serum level of 5-fluorouracil could be determined. Pain and secondary infections were important side effects in our patients. However, in patients with extensive NMSC this treatment may be considered

Age-related changes in the local milieu of inflamed tissues cause aberrant neutrophil trafficking and subsequent remote organ damage

Aging is associated with dysregulated immune functions. Here, we investigated the impact of age on neutrophil diapedesis. Using confocal intravital microscopy, we found that in inflamed aged tissues neutrophils exhibited a high frequency of reverse transendothelial migration (rTEM). This retrograde breaching of the endothelium by neutrophils was governed by enhanced production of the chemokine CXCL1 from mast cells that localized at endothelial cell (EC) junctions. Increased EC expression of the atypical chemokine receptor 1 (ACKR1) supported this pro-inflammatory milieu in aged venules. Accumulation of CXCL1 caused desensitization of the chemokine receptor CXCR2 on neutrophils and loss of neutrophil directional motility within EC junctions. Fluorescent tracking revealed that in aged mice, neutrophils undergoing rTEM re-entered the circulation and disseminated to the lungs where they caused vascular leakage. Thus, neutrophils stemming from a local inflammatory site contribute to remote organ damage, with implication to the dysregulated systemic inflammation associated with aging

Age-related changes in the local milieu of inflamed tissues cause aberrant neutrophil trafficking and subsequent remote organ damage

Aging is associated with dysregulated immune functions. Here, we investigated the impact of age on neutrophil diapedesis. Using confocal intravital microscopy, we found that in aged mice, neutrophils adhered to vascular endothelium in inflamed tissues but exhibited a high frequency of reverse transendothelial migration (rTEM). This retrograde breaching of the endothelium by neutrophils was governed by enhanced production of the chemokine CXCL1 from mast cells that localized at endothelial cell (EC) junctions. Increased EC expression of the atypical chemokine receptor 1 (ACKR1) supported this pro-inflammatory milieu in aged venules. Accumulation of CXCL1 caused desensitization of the chemokine receptor CXCR2 on neutrophils and loss of neutrophil directional motility within EC junctions. Fluorescent tracking revealed that in aged mice, neutrophils undergoing rTEM re-entered the circulation and disseminated to the lungs where they caused vascular leakage. Thus, neutrophils stemming from a local inflammatory site contribute to remote organ damage, with implication to the dysregulated systemic inflammation associated with aging

Exploiting Residue Curve Maps to Assess Thermodynamic Feasibility Boundaries under Uncertain Operating Conditions

The very first step of almost any separation process design procedure is the thermodynamic feasibility analysis. In the case of distillation, residue curve maps (RCMs) represent an essential tool to assess whether the separation is feasible or not. However, the analysis is generally carried out by referring to nominal operating conditions and product purities as specification. This means that, when process parameters are likely to undergo fluctuations, the prediction of the system response is not that obvious. An ABE/W (acetone−butanol−ethanol/water) mixture was then selected as a case study since it allows us to discuss several non-ideal thermodynamic behaviors and because of the renewed interest in biorefinery and sustainable processes during recent years. Residue curve mapping was then exploited to determine the thermodynamic feasibility range for multicomponent distillation processes as well as for distillation trains and process-intensified solutions taking into account both product purity and product recovery specifications. The final product of this study is a thorough procedure to determine the flexibility boundaries of feed and product compositions as well as an immediate and intuitive graphical representation from a binary standard distillation column to a complex multicomponent dividing wall column applicatio

Neutrophil breaching of the blood vessel pericyte layer during diapedesis requires mast cell-derived IL-17A

Neutrophil diapedesis is an immediate step following infections and injury and is driven by complex interactions between leukocytes and various components of the blood vessel wall. Here, we show that perivascular mast cells (MC) are key regulators of neutrophil behaviour within the sub-endothelial space of inflamed venules. Using confocal intravital microscopy, we observe directed abluminal neutrophil motility along pericyte processes towards perivascular MCs, a response that created neutrophil extravasation hotspots. Conversely, MC-deficiency and pharmacological or genetic blockade of IL-17A leads to impaired neutrophil sub-endothelial migration and breaching of the pericyte layer. Mechanistically, identifying MCs as a significant cellular source of IL-17A, we establish that MC-derived IL-17A regulates the enrichment of key effector molecules ICAM-1 and CXCL1 in nearby pericytes. Collectively, we identify a novel MC-IL-17A-pericyte axis as modulator of the final steps of neutrophil diapedesis, with potential translational implications for inflammatory disorders driven by increased neutrophil diapedesis

The C313Y Piedmontese mutation decreases myostatin covalent dimerisation and stability

<p>Abstract</p> <p>Background</p> <p>Myostatin is a key negative regulator of muscle growth and development, whose activity has important implications for the treatment of muscle wastage disorders. Piedmontese cattle display a double-muscled phenotype associated with the expression of C313Y mutant myostatin. <it>In vivo</it>, C313Y myostatin is proteolytically processed, exported and circulated extracellularly but fails to correctly regulate muscle growth. The C313Y mutation removes the C313-containing disulphide bond, an integral part of the characteristic TGF-β cystine-knot structural motif.</p> <p>Results</p> <p>Here we present <it>in vitro </it>analysis of the structure and stability of the C313Y myostatin protein that reveals significantly decreased covalent dimerisation for C313Y myostatin accompanied by a loss of structural stability compared to wild type. The C313Y myostatin growth factor, processed from full length precursor protein, fails to inhibit C2C12 myoblast proliferation in contrast to wild type myostatin. Although structural modeling shows the substitution of tyrosine causes structural perturbation, biochemical analysis of additional disulphide mutants, C313A and C374A, indicates that an intact cystine-knot motif is a major determinant in myostatin growth factor stability and covalent dimerisation.</p> <p>Conclusions</p> <p>This research shows that the cystine-knot structure is important for myostatin dimerisation and stability, and that disruption of this structural motif perturbs myostatin signaling.</p

Directed Neural Differentiation of Mouse Embryonic Stem Cells Is a Sensitive System for the Identification of Novel Hox Gene Effectors

The evolutionarily conserved Hox family of homeodomain transcription factors plays fundamental roles in regulating cell specification along the anterior posterior axis during development of all bilaterian animals by controlling cell fate choices in a highly localized, extracellular signal and cell context dependent manner. Some studies have established downstream target genes in specific systems but their identification is insufficient to explain either the ability of Hox genes to direct homeotic transformations or the breadth of their patterning potential. To begin delineating Hox gene function in neural development we used a mouse ES cell based system that combines efficient neural differentiation with inducible Hoxb1 expression. Gene expression profiling suggested that Hoxb1 acted as both activator and repressor in the short term but predominantly as a repressor in the long run. Activated and repressed genes segregated in distinct processes suggesting that, in the context examined, Hoxb1 blocked differentiation while activating genes related to early developmental processes, wnt and cell surface receptor linked signal transduction and cell-to-cell communication. To further elucidate aspects of Hoxb1 function we used loss and gain of function approaches in the mouse and chick embryos. We show that Hoxb1 acts as an activator to establish the full expression domain of CRABPI and II in rhombomere 4 and as a repressor to restrict expression of Lhx5 and Lhx9. Thus the Hoxb1 patterning activity includes the regulation of the cellular response to retinoic acid and the delay of the expression of genes that commit cells to neural differentiation. The results of this study show that ES neural differentiation and inducible Hox gene expression can be used as a sensitive model system to systematically identify Hox novel target genes, delineate their interactions with signaling pathways in dictating cell fate and define the extent of functional overlap among different Hox genes

Leptin Administration Favors Muscle Mass Accretion by Decreasing FoxO3a and Increasing PGC-1α in ob/ob Mice

Absence of leptin has been associated with reduced skeletal muscle mass in leptin-deficient ob/ob mice. The aim of our study was to examine the effect of leptin on the catabolic and anabolic pathways regulating muscle mass. Gastrocnemius, extensor digitorum longus and soleus muscle mass as well as fiber size were significantly lower in ob/ob mice compared to wild type littermates, being significantly increased by leptin administration (P<0.001). This effect was associated with an inactivation of the muscle atrophy-related transcription factor forkhead box class O3 (FoxO3a) (P<0.05), and with a decrease in the protein expression levels of the E3 ubiquitin-ligases muscle atrophy F-box (MAFbx) (P<0.05) and muscle RING finger 1 (MuRF1) (P<0.05). Moreover, leptin increased (P<0.01) protein expression levels of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), a regulator of muscle fiber type, and decreased (P<0.05) myostatin protein, a negative regulator of muscle growth. Leptin administration also activated (P<0.01) the regulators of cell cycle progression proliferating cell nuclear antigen (PCNA) and cyclin D1, and increased (P<0.01) myofibrillar protein troponin T. The present study provides evidence that leptin treatment may increase muscle mass of ob/ob mice by inhibiting myofibrillar protein degradation as well as enhancing muscle cell proliferation

Effet d’une situation d’apnée statique sur les capacités individuelles d’estimation du temps

International audienceIntroduction. – Apnea is known to induce specific physiological adaptation in order to protect brain and heart from hypoxia. During apnea, ability to accurately estimate time is the main factor to keep watch over it in order to perform safely. Therefore, the present study aimed to analyse the effect of static apnea on internal clock processes.Fact synthesis. – As expected, continuous heart rate monitoring appeared to be a good marker of biological activity. Five trials of time production (20 s) were performed by the subjects, in a sitting position using a chronometer. Time production was studied during three experimental conditions: at rest before static apnea, during five short static apneas (less than 1 min) and at rest after static apneas. Compared to rest, static apnea induced a bradycardia and an underestimation of time interval.Conclusion. – As previously reported in the literature, time processes and biological activity seemed to be connected. The apneic bradycardia could reflect a decrease in biological activity (primarily in order to decrease oxygen uptake) which might consequently influence time estimation mechanisms. If subjects underestimate time during static apnea, then any additional time spent in breath-hold condition could increase oxygen deficit and therefore lead to free diving accident.Introduction. – L'apnée réalisée en milieu aérien comme aquatique induit des adaptations physiologiques ayant pour objectif de maintenir la perfusion des organes « nobles » (cerveau, coeur). Lors de sa réalisation en immersion, la gestion du temps est primordiale afin d'accomplir une performance sans se mettre en situation de danger. Ainsi, on peut se demander dans quelles mesures l'apnée statique peut perturber l'estimation du temps ?Synthèse des faits. – La fréquence cardiaque des sujets, enregistrée en continu, peut être considérée comme un bon témoin du niveau de l'activité biologique. Les productions des sujets (production manuelle avec un chronomètre d'un intervalle estimé de 20 s) en situation de repos (position assise) et de récupération ne sont pas significativement différentes et sont considérées comme valeurs contrôles. L'apnée statique, qui induit une bradycardie, est également accompagnée d'une sous-estimation de la durée écoulée, mais significativement plus importante que lors du repos.Conclusion. – Il semble exister une corrélation entre le niveau d'activité biologique et les processus d'estimation temporelle : la bradycardie apnéique semble être le reflet d'une baisse de l'activité biologique entraînant une mauvaise estimation de la durée écoulée. Les sujets sous-estiment le temps en apnée statique, augmentant ainsi les déficits en oxygène de l'organisme et par conséquent le facteur de risque de syncopes hypoxiques