Attenuated expression of tenascin-c in ovalbumin-challenged STAT4-/- mice

Background

Asthma leads to structural changes in the airways, including the modification of extracellular matrix proteins such as tenascin-C. The role of tenascin-C is unclear, but it might act as an early initiator of airway wall remodelling, as its expression is increased in the mouse and human airways during allergic inflammation. In this study, we examined whether Th1 or Th2 cells are important regulators of tenascin-C in experimental allergic asthma utilizing mice with impaired Th1 (STAT4-/-) or Th2 (STAT6-/-) immunity.

Methods

Balb/c wildtype (WT), STAT4-/- and STAT6-/- mice were sensitized with intraperitoneally injected ovalbumin (OVA) followed by OVA or PBS airway challenge. Airway hyperreactivity (AHR) was measured and samples were collected. Real time PCR and immunohistochemistry were used to study cytokines and differences in the expression of tenascin-C. Tenascin-C expression was measured in human fibroblasts after treatment with TNF-α and IFN-γ in vitro.

Results

OVA-challenged WT mice showed allergic inflammation and AHR in the airways along with increased expression of TNF-α, IFN-γ, IL-4 and tenascin-C in the lungs. OVA-challenged STAT4-/- mice exhibited elevated AHR and pulmonary eosinophilia. The mRNA expression of TNF-α and IFN-γ was low, but the expression of IL-4 was significantly elevated in these mice. OVA-challenged STAT6-/- mice had neither AHR nor pulmonary eosinophilia, but had increased expression of mRNA for TNF-α, IFN-γ and IL-4. The expression of tenascin-C in the lungs of OVA-challenged STAT4-/- mice was weaker than in those of OVA-challenged WT and STAT6-/- mice suggesting that TNF-α and IFN-γ may regulate tenascin-C expression in vivo. The stimulation of human fibroblasts with TNF-α and IFN-γ induced the expression of tenascin-C confirming our in vivo findings.

Conclusions

Expression of tenascin-C is significantly attenuated in the airways of STAT4-/- mice, which may be due to the impaired secretion of TNF-α and IFN-γ in these mice.     

Biochemical and pharmacological characterization of human α/β-hydrolase domain containing 6 (ABHD6) and 12 (ABHD12)

In the central nervous system, three enzymes belonging to the serine hydrolase family are thought to regulate the life time of the endocannabinoid 2-arachidonoylglycerol (C20:4) (2-AG). From these, monoacylglycerol lipase (MAGL) is well characterized and, on a quantitative basis, is the main 2-AG hydrolase. The postgenomic proteins α/β-hydrolase domain containing (ABHD)6 and ABHD12 remain poorly characterized. By applying a sensitive fluorescent glycerol assay, we delineate the substrate preferences of human ABHD6 and ABHD12 in comparison with MAGL. We show that the three hydrolases are genuine MAG lipases; medium-chain saturated MAGs were the best substrates for hABHD6 and hMAGL, whereas hABHD12 preferred the 1 (3)- and 2-isomers of arachidonoylglycerol. Site-directed mutagenesis of the amino acid residues forming the postulated catalytic triad (ABHD6: S148-D278-H306, ABHD12: S246-D333-H372) abolished enzymatic activity as well as labeling with the active site serine-directed fluorophosphonate probe TAMRA-FP. However, the role of D278 and H306 as residues of the catalytic core of ABHD6 could not be verified because none of the mutants showed detectable expression. Inhibitor profiling revealed striking potency differences between hABHD6 and hABHD12, a finding that, when combined with the substrate profiling data, should facilitate further efforts toward the design of potent and selective inhibitors, especially those targeting hABHD12, which currently lacks such inhibitors.     

CD200 positive human mesenchymal stem cells suppress TNF-alpha secretion from CD200 receptor positive macrophage-like cells

Human mesenchymal stem cells (hMSCs) display immunosuppressive properties in vitro and the potential has also been transferred successfully to clinical trials for treatment of autoimmune diseases. OX-2 (CD200), a member of the immunoglobulin superfamily, is widely expressed in several tissues and has recently been found from hMSCs. The CD200 receptor (CD200R) occurs only in myeloid-lineage cells. The CD200-CD200R is involved in down-regulation of several immune cells, especially macrophages. The present study on 20 hMSC lines shows that the CD200 expression pattern varied from high (CD200Hi) to medium (CD200Me) and low (CD200Lo) in bone marrow-derived mesenchymal stem cell (BMMSC) lines, whereas umbilical cord blood derived mesenchymal stem cells (UCBMSCs) were constantly negative for CD200. The role of the CD200-CD200R axis in BMMSCs mediated immunosuppression was studied using THP-1 human macrophages. Interestingly, hMSCs showed greater inhibition of TNF-α secretion in co-cultures with IFN-γ primed THP-1 macrophages when compared to LPS activated cells. The ability of CD200Hi BMMSCs to suppress TNF-α secretion from IFN-γ stimulated THP-1 macrophages was significantly greater when compared to CD200Lo whereas UCBMSCs did not significantly reduce TNF-α secretion. The interference of CD200 binding to the CD200R by anti-CD200 antibody weakened the capability of BMMSCs to inhibit TNF-α secretion from IFN-γ activated THP-1 macrophages. This study clearly demonstrated that the efficiency of BMMSCs to suppress TNF-α secretion of THP-1 macrophages was dependent on the type of stimulus. Moreover, the CD200-CD200r axis could have a previously unidentified role in the BMMSC mediated immunosuppression.     

Sequence features and evolutionary mechanisms in the chicken avidin gene family.

The chicken avidin gene family comprises the avidin gene (avd) and several homologous avidin-related genes (avrs). The sequences of the avr genes are nearly identical to each other but exhibit nonrandomly distributed, frequently nonsynonymous nucleotide substitutions compared to avd. In this study, we determined the genetic distances and the phylogeny of the avd and avr genes and found differences between different exons and introns. Our results suggest the involvement of biased gene conversion in the evolution of the genes. Furthermore, one of the genes was identified as a putative fusion gene. The occurrence of both gene conversion and recombination supports the models suggesting a common initiation mechanism for conversion and crossing-over. The existence of avidin-related proteins (AVRs) is currently unknown, but the putative AVRs are expected to bind biotin similarly to avidin. However, the observed sequence differences may affect the stability and glycosylation patterns of the putative AVR proteins.     

Gender influence on vasoactive hormones at rest and during a 70 degrees head-up tilt in healthy humans.

To evaluate the influence of age and gender on the neuroendocrine control of blood pressure in normal subjects, a 13-min 70 degrees head-up tilt (HUT) was applied after 3 h of recumbency to 109 healthy men and women aged 23-50 yr (age group I) and 51-77 yr (age group II). We found that age and gender had a significant influence on plasma norepinephrine (PNE) concentration at baseline and in the upright position. PNE was significantly higher in older men compared with the younger men and women of both age groups, suggesting a divergent age-related activation of the sympathetic nervous system between genders at baseline as well as during a sustained orthostatic challenge. There was no significant influence of age or gender on plasma epinephrine at baseline or during HUT. Plasma renin activity was significantly higher at baseline as well as in the upright position during HUT in elderly men than in women. Age or gender had no influence on plasma vasopressin (PAVP), and, regardless of age, nonhypotensive HUT induced an extremely modest increase in PAVP. The syncopal subjects displayed a hormonal pattern associating increased PNE and a surge in plasma epinephrine and PAVP minutes before syncope during HUT. The orthostatic intolerance appears not to be a feature of healthy aging per se. In healthy subjects, both age and gender modulate markedly the cardiovascular and neuroendocrine responses to an orthostatic challenge and must be taken into consideration, particularly when catecholamine responses are studied.     

VIP like immunoreactive nerves in human respiratory tract. Light and electron microscopic study

The present study provides light and electron microscopical evidence of Vasoactive Intestinal Peptide - (VIP) like immunoreactive nerves in human lower respiratory tract. Peroxidase antiperoxidase (PAP) technique was used to localize VIP-like immunoreactivity light microscopically and ultrastructurally. Under light microscopy, VIP-like immunoreactive nerves were observed in the smooth muscle layer of secondary bronchi to small bronchioli, and in bronchial glands. In addition, positive immunoreactive nervous network to VIP was found around nerve cell bodies in small microganglia. The bronchial epithelium of airway tract did not receive any VIP positive nerve fibers. Ultrastructurally VIP-like positive immunoreaction was localized in large granular vesicles ranging from 90 to 210 nm. Usually VIP-like positive immunoreactive nerve profiles contained several immunoreactive large vesicles (100-210). However, nerve profiles containing only a few positive large vesicles (80-150) were also observed. Under electron microscopy VIP-positive nerve profiles corresponded ultrastructurally to nerve profiles containing large granular vesicles observed in conventional electronmicroscopy. The present study provides new information about the innervation of human lower airway tract and widens the concept of their functional regulation on the anatomical basis reported here.     

CT-guided ablative stereotaxis without ventriculography

A new technique is described which permits all types of stereotactic surgery to be done without ventriculography, with CT guidance only. The present series consists of 42 patients who underwent thalamotomy, posteromedial hypothalamotomy, dentatotomy or anterior capsulotomy for movement disorders, chronic pain, spasmodic torticollis or psychiatric illness. Postoperative lesion control with repeated CT showed that the method was accurate. The clinical results were considered to be better than those after previous ventriculography-guided surgery. It is concluded that ventriculography is no longer needed for stereotactic neurosurgery.     

Ornithine Decarboxylase Activity in Brain Regulated by a Specific Macromolecul, the Antizyme

Mouse brain ornithine decarboxylase activity is about 70-fold higher at the time of birth compared with that of adult mice. Enzyme activity declines rapidly after birth and reaches the adult level by 3 weeks. Immunoreactive enzyme concentration parallels very closely the decrease of enzyme activity during the first postnatal week, remaining constant thereafter. The content of brain antizyme, the macromolecular inhibitor to ornithine decarboxylase, in turn is very low during the first 7 days and starts then to increase and at the age of 3 weeks it is about six times the level of that in newborn mice. This may explain the decrease in enzyme activity during brain maturation, and suggests the regulation of polyamine biosynthesis by an antizyme-mediated mechanism in adult brain.     

Relationship between tracheal mucosal thickness and vascular resistance in dogs

We have measured changes in tracheal mucosal thickness and tracheal vascular resistance in the dog. A probe was used to detect changes in height with time of the tracheal epithelium relative to an underlying cartilage. Tracheal vascular resistance was determined by perfusing a cranial tracheal artery at constant flow and measuring inflow pressure. Various drugs injected close-arterially were tested in 20 greyhounds anesthetized with pentobarbital sodium. Bradykinin, histamine, and methacholine significantly (P less than 0.01) decreased vascular resistance (-39.3 +/- 3.7, -47.3 +/- 4.2, and -22.5 +/- 5.2%, respectively) and increased the thickness of the mucosa (119.0 +/- 25.0, 61.9 +/- 25.0, and 46.3 +/- 6.4 micron). Substance P, vasoactive intestinal peptide, prostaglandin F2 alpha, and prostaglandin E, had large vasodilator actions (-31.4 +/- 5.0, -34.3 +/- 2.2, -21.9 +/- 2.8, and -31.5 +/- 2.4%) but only small effects on mucosal thickness (12.3 +/- 3.9, 13.0 +/- 3.4, 16.7 +/- 6.5, and 8.7 +/- 2.9 micron, respectively). Phenylephrine hydrochloride increased vascular resistance (19.8 +/- 1.7%) and decreased mucosal thickness (-23.9 +/- 3.1 micron). Thus airway vascular resistance and mucosal thickness always change in opposite directions, but drugs have different relative actions on the two variables. Even with large vasodilatations, the absolute changes in mucosal thickness were small and were unlikely to have an appreciable effect on tracheal airway resistance.     

Gut microbiota composition is associated with environmental landscape in honey bees

There is growing recognition that the gut microbial community regulates a wide variety of important functions in its animal hosts, including host health. However, the complex interactions between gut microbes and environment are still unclear. Honey bees are ecologically and economically important pollinators that host a core gut microbial community that is thought to be constant across populations. Here, we examined whether the composition of the gut microbial community of honey bees is affected by the environmental landscape the bees are exposed to. We placed honey bee colonies reared under identical conditions in two main landscape types for 6 weeks: either oilseed rape farmland or agricultural farmland distant to fields of flowering oilseed rape. The gut bacterial communities of adult bees from the colonies were then characterized and compared based on amplicon sequencing of the 16S rRNA gene. While previous studies have delineated a characteristic core set of bacteria inhabiting the honey bee gut, our results suggest that the broad environment that bees are exposed to has some influence on the relative abundance of some members of that microbial community. This includes known dominant taxa thought to have functions in nutrition and health. Our results provide evidence for an influence of landscape exposure on honey bee microbial community and highlight the potential effect of exposure to different environmental parameters, such as forage type and neonicotinoid pesticides, on key honey bee gut bacteria. This work emphasizes the complexity of the relationship between the host, its gut bacteria, and the environment and identifies target microbial taxa for functional analyses.