A Midbrain Circuit that Mediates Headache Aversiveness in Rats.

Migraines are a major health burden, but treatment is limited because of inadequate understanding of neural mechanisms underlying headache. Imaging studies of migraine patients demonstrate changes in both pain-modulatory circuits and reward-processing regions, but whether these changes contribute to the experience of headache is unknown. Here, we demonstrate a direct connection between the ventrolateral periaqueductal gray (vlPAG) and the ventral tegmental area (VTA) that contributes to headache aversiveness in rats. Many VTA neurons receive monosynaptic input from the vlPAG, and cranial nociceptive input increases Fos expression in VTA-projecting vlPAG neurons. Activation of PAG inputs to the VTA induces avoidance behavior, while inactivation of these projections induces a place preference only in animals with headache. This work identifies a distinct pathway that mediates cranial nociceptive aversiveness

An anti-siglec-8 antibody depletes sputum eosinophils from asthmatic subjects and inhibits lung mast cells

Background Sialic acid-binding immunoglobulin-like lectin (Siglec)-8 is expressed on mast cells and eosinophils, but information about Siglec-8 expression and function in the lung is limited. A humanized antibody, AK002, targeting Siglec-8 is undergoing development for treatment of diseases associated with mast cell and eosinophil-driven inflammation. Objective To characterize Siglec-8 expression in the airway in asthma and determine whether antibodies that target Siglec-8 (S8mAbs) can decrease airway eosinophils in asthma or inhibit lung mast cell activation. Methods Gene expression profiling and flow cytometry were used to characterize Siglec-8 expression in sputum cells from stable asthma. An antibody-dependent cellular cytotoxicity (ADCC) assay was used to determine whether an S8mAb can decrease eosinophils in sputum from asthma patients ex vivo. A mast cell activation assay was used to determine whether an S8mAb can inhibit mast cell activation in human lung tissue ex vivo. Results Gene expression for Siglec-8 is increased in sputum cells in asthma and correlates with gene expression for eosinophils and mast cells. Gene expression for Siglec-8 is inversely and significantly correlated with measures of airflow obstruction in asthma patients. Siglec-8 is prominently expressed on the surface of eosinophils and mast cells in sputum. S8mAbs decrease eosinophils in sputum from patients with asthma and inhibit Fc epsilon R1-activated mast cells in lung tissues. Conclusions and Clinical Relevance Siglec-8 is highly expressed on eosinophils and mast cells in asthmatic sputum and targeting Siglec-8 with an antibody is a plausible strategy to decrease sputum eosinophils and inhibit lung mast cells in asthma

ENU Mutagenesis Reveals a Novel Phenotype of Reduced Limb Strength in Mice Lacking Fibrillin 2

Background: Fibrillins 1 (FBN1) and 2 (FBN2) are components of microfibrils, microfilaments that are present in many connective tissues, either alone or in association with elastin. Marfan's syndrome and congenital contractural arachnodactyly (CCA) result from dominant mutations in the genes FBN1 and FBN2 respectively. Patients with both conditions often present with specific muscle atrophy or weakness, yet this has not been reported in the mouse models. In the case of Fbn1, this is due to perinatal lethality of the homozygous null mice making measurements of strength difficult. In the case of Fbn2, four different mutant alleles have been described in the mouse and in all cases syndactyly was reported as the defining phenotypic feature of homozygotes.Methodology/Principal Findings: As part of a large-scale N-ethyl-N-nitrosourea (ENU) mutagenesis screen, we identified a mouse mutant, Mariusz, which exhibited muscle weakness along with hindlimb syndactyly. We identified an amber nonsense mutation in Fbn2 in this mouse mutant. Examination of a previously characterised Fbn2-null mutant, Fbn2(fp), identified a similar muscle weakness phenotype. The two Fbn2 mutant alleles complement each other confirming that the weakness is the result of a lack of Fbn2 activity. Skeletal muscle from mutants proved to be abnormal with higher than average numbers of fibres with centrally placed nuclei, an indicator that there are some regenerating muscle fibres. Physiological tests indicated that the mutant muscle produces significantly less maximal force, possibly as a result of the muscles being relatively smaller in Mariusz mice.Conclusions: These findings indicate that Fbn2 is involved in integrity of structures required for strength in limb movement. As human patients with mutations in the fibrillin genes FBN1 and FBN2 often present with muscle weakness and atrophy as a symptom, Fbn2-null mice will be a useful model for examining this aspect of the disease process further

Relative contributions and mapping of ventral tegmental area dopamine and GABA neurons by projection target in the rat

The ventral tegmental area (VTA) is a heterogeneous midbrain structure that contains dopamine (DA), GABA, and glutamate neurons that project to many different brain regions. Here, we combined retrograde tracing with immunocytochemistry against tyrosine hydroxylase (TH) or glutamate decarboxylase (GAD) to systematically compare the proportion of dopaminergic and GABAergic VTA projections to 10 target nuclei: anterior cingulate, prelimbic, and infralimbic cortex; nucleus accumbens core, medial shell, and lateral shell; anterior and posterior basolateral amygdala; ventral pallidum; and periaqueductal gray. Overall, the non-dopaminergic component predominated VTA efferents, accounting for more than 50% of all projecting neurons to each region except the nucleus accumbens core. In addition, GABA neurons contributed no more than 20% to each projection, with the exception of the projection to the ventrolateral periaqueductal gray, where the GABAergic contribution approached 50%. Therefore, there is likely a significant glutamatergic component to many of the VTA's projections. We also found that VTA cell bodies retrogradely labeled from the various target brain regions had distinct distribution patterns within the VTA, including in the locations of DA and GABA neurons. Despite this patterned organization, VTA neurons comprising these different projections were intermingled and never limited to any one subregion. These anatomical results are consistent with the idea that VTA neurons participate in multiple distinct, parallel circuits that differentially contribute to motivation and reward. While attention has largely focused on VTA DA neurons, a better understanding of VTA subpopulations, especially the contribution of non-DA neurons to projections, will be critical for future work5275916941sem informaçãosem informaçã

An anti‐siglec‐8 antibody depletes sputum eosinophils from asthmatic subjects and inhibits lung mast cells

Background Sialic acid-binding immunoglobulin-like lectin (Siglec)-8 is expressed on mast cells and eosinophils, but information about Siglec-8 expression and function in the lung is limited. A humanized antibody, AK002, targeting Siglec-8 is undergoing development for treatment of diseases associated with mast cell and eosinophil-driven inflammation. Objective To characterize Siglec-8 expression in the airway in asthma and determine whether antibodies that target Siglec-8 (S8mAbs) can decrease airway eosinophils in asthma or inhibit lung mast cell activation. Methods Gene expression profiling and flow cytometry were used to characterize Siglec-8 expression in sputum cells from stable asthma. An antibody-dependent cellular cytotoxicity (ADCC) assay was used to determine whether an S8mAb can decrease eosinophils in sputum from asthma patients ex vivo. A mast cell activation assay was used to determine whether an S8mAb can inhibit mast cell activation in human lung tissue ex vivo. Results Gene expression for Siglec-8 is increased in sputum cells in asthma and correlates with gene expression for eosinophils and mast cells. Gene expression for Siglec-8 is inversely and significantly correlated with measures of airflow obstruction in asthma patients. Siglec-8 is prominently expressed on the surface of eosinophils and mast cells in sputum. S8mAbs decrease eosinophils in sputum from patients with asthma and inhibit Fc epsilon R1-activated mast cells in lung tissues. Conclusions and Clinical Relevance Siglec-8 is highly expressed on eosinophils and mast cells in asthmatic sputum and targeting Siglec-8 with an antibody is a plausible strategy to decrease sputum eosinophils and inhibit lung mast cells in asthma

A novel thiol-saccharide mucolytic for the treatment of muco-obstructive lung diseases

BackgroundMucin disulfide cross-links mediate pathologic mucus formation in muco-obstructive lung diseases. MUC-031, a novel thiol-modified carbohydrate compound, cleaves disulfides to cause mucolysis. The aim of this study was to determine the mucolytic and therapeutic effects of MUC-031 in sputum from patients with cystic fibrosis (CF) and mice with muco-obstructive lung disease (βENaC-Tg mice).MethodsWe compared the mucolytic efficacy of MUC-031 and existing mucolytics (N-acetylcysteine (NAC) and recombinant human deoxyribonuclease I (rhDNase)) using rheology to measure the elastic modulus (G') of CF sputum, and we tested effects of MUC-031 on airway mucus plugging, inflammation and survival in βENaC-Tg mice to determine its mucolytic efficacy in vivo.ResultsIn CF sputum, compared to the effects of rhDNase and NAC, MUC-031 caused a larger decrease in sputum G', was faster in decreasing sputum G' by 50% and caused mucolysis of a larger proportion of sputum samples within 15 min of drug addition. Compared to vehicle control, three treatments with MUC-031 in 1 day in adult βENaC-Tg mice decreased airway mucus content (16.8±3.2 versus 7.5±1.2 nL·mm-2, p<0.01) and bronchoalveolar lavage cells (73 833±6930 versus 47 679±7736 cells·mL-1, p<0.05). Twice-daily treatment with MUC-031 for 2 weeks also caused decreases in these outcomes in adult and neonatal βENaC-Tg mice and reduced mortality from 37% in vehicle-treated βENaC-Tg neonates to 21% in those treated with MUC-031 (p<0.05).ConclusionMUC-031 is a potent and fast-acting mucolytic that decreases airway mucus plugging, lessens airway inflammation and improves survival in βENaC-Tg mice. These data provide rationale for human trials of MUC-031 in muco-obstructive lung diseases