uPA‐uPAR molecular complex is involved in cell signaling during neuronal migration and neuritogenesis

Background: In the development of the central nervous system (CNS), neuronal migration and neuritogenesis are crucial processes for establishing functional neural circuits. This relies on the regulation exerted by several signaling molecules, which play important roles in axonal growth and guidance. The urokinase‐type plasminogen activator (uPA)—in association with its receptor—triggers extracellular matrix proteolysis and other cellular processes through the activation of intracellular signaling pathways. Even though the uPA‐uPAR complex is well characterized in nonneuronal systems, little is known about its signaling role during CNS development. Results : In response to uPA, neuronal migration and neuritogenesis are promoted in a dose‐dependent manner. After stimulation, uPAR interacts with α₅‐ and β₁‐integrin subunits, which may constitute an αβ‐heterodimer that acts as a uPA‐uPAR coreceptor favoring the activation of multiple kinases. This interaction may be responsible for the uPA‐promoted phosphorylation of focal adhesion kinase (FAK) and its relocation toward growth cones, triggering cytoskeletal reorganization which, in turn, induces morphological changes related to neuronal migration and neuritogenesis. Conclusions : uPA has a key role during CNS development. In association with its receptor, it orchestrates both proteolytic and nonproteolytic events that govern the proper formation of neural networks. Developmental Dynamics 243:676–689, 2014. © 2014 Wiley Periodicals, Inc.     

Serum from aged F344 rats conditions the activation of young macrophages

There is considerable controversy about the molecular mechanisms responsible for the variations in innate immunity associated with age. While in vivo, aged animals and humans react to an inflammatory signal with an excessive production of pro-inflammatory cytokines, studies in vitro generally show that this response is attenuated in macrophages from old individuals. In an effort to examine possible extrinsic factors that might affect the response of macrophages to lipopolysaccharide (LPS), we have challenged peritoneal macrophages obtained from young rats with sera obtained from rats of different ages. Our results indicate that the serum from aged rats significantly impairs the capacity of young macrophages to induce tumor necrosis factor-alpha (TNF-alpha) production, while at the same time it increases the basal levels of interleukin-6 (IL-6). The effect of serum from aged donors on TNF-alpha secretion requires pre-incubation and is sensitive to heat inactivation. In contrast, the stimulating effect on IL-6 is resistant to heat, and thus should not be due to a protein factor. Therefore, our results indicate that the age-related changes in macrophage activity are not only the consequence of intrinsic changes, but there also appears to be a modulatory effect imparted by the external milieu.     

Respiratory cooling and thermoregulatory coupling in reptiles

Comparative physiological research on reptiles has focused primarily on the understanding of mechanisms of the control of breathing as they relate to respiratory gases or temperature itself. Comparatively less research has been done on the possible link between breathing and thermoregulation. Reptiles possess remarkable thermoregulatory capabilities, making use of behavioural and physiological mechanisms to regulate body temperature. The presence of thermal panting and gaping in numerous reptiles, coupled with the existence of head-body temperature differences, suggests that head temperature may be the primary regulated variable rather than body temperature. This review examines the preponderance of head and body temperature differences in reptiles, the occurrence of breathing patterns that possess putative thermoregulatory roles, and the propensity for head and brain temperature to be controlled by reptiles, particularly at higher temperatures. The available evidence suggests that these thermoregulatory breathing patterns are indeed present, though primarily in arid-dwelling reptiles. More importantly, however, it appears that the respiratory mechanisms that have the capacity to cool evolved initially in reptiles, perhaps as regulatory mechanisms for preventing overheating of the brain. Examining the control of these breathing patterns and their efficacy at regulating head or brain temperature may shed light on the evolution of thermoregulatory mechanisms in other vertebrates, namely the endothermic mammals and birds.     

High‐amplitude theta wave bursts characterizing narcoleptic mice and patients are also produced by histamine deficiency in mice

Histamine and orexins are wake promoters released by hypothalamic neurons. The activity of histamine neurons is increased by orexin neurons. Recently, it has been shown that orexin deficiency entails high‐amplitude theta wave bursts during rapid eye movement sleep and cataplexy in narcoleptic mice. The primary aim of this study was to assess whether histamine system is involved in high‐amplitude theta wave burst generation during rapid eye movement sleep. The secondary aim was to assess the effects of combined histamine and orexin deficiency on high‐amplitude theta wave bursts during rapid eye movement sleep in mice. Twelve histidine‐decarboxylase knockout mice with congenital histamine deficiency, seven double mutant mice with combined deficiency of orexin neurons and histamine, and 11 wild‐type control mice were studied with electrodes for sleep recordings and a telemetric blood pressure transducer. High‐amplitude theta wave bursts during rapid eye movement sleep were detected in each of the histidine‐decarboxylase knockout and double mutant mice, whereas only one burst was found in a wild‐type control mouse. High‐amplitude theta wave bursts occurred significantly more often and were significantly longer in double mutant than in histidine‐decarboxylase knockout mice. In conclusion, it was demonstrated that, similarly to orexin, the chronic impairment of histamine entailed high‐amplitude theta wave bursts during rapid eye movement sleep. The current data also suggested a synergistic role of orexin and histamine signalling on high‐amplitude theta wave bursts during rapid eye movement sleep in mice.     

An in vivo role for Trypanosoma cruzi calreticulin in antiangiogenesis

Angiogenesis leads to neovascularization from existing blood vessels. It is associated with tumor growth and metastasis and is regulated by pro- and antiangiogenic molecules, some of them currently under clinical trials for cancer treatment. During the last few years we have cloned, sequenced and expressed a Trypanosoma cruzi calreticulin gene (TcCRT). Its product, TcCRT, a 45 kDa protein, is more than 50% identical to human CRT (HuCRT). TcCRT, present on the surface of trypomastigotes, binds both C1q and mannan binding lectin and inhibits the classical activation pathway of human complement. Since TcCRT is highly homologous to a functional antiangiogenic fragment from HuCRT (aa 120–180), recombinant (r) and native (n) TcCRT were tested in their antiangiogenic effects, in the chick embryonic chorioallantoid membrane (CAM) assay. Both proteins mediated highly significant antiangiogenic effects in the in vivo CAM assay. This effect was further substantiated in experiments showing that the plasmid construct pSecTag/TcCRT also displayed significant antiangiogenic properties, as compared to the empty vector. Most likely, the fact that antiangiogenic substances act preferentially on growing neoplasic tissues, but not on already established tumors, is due to their effects on emerging blood vessels. The results shown here indicate that TcCRT, like its human counterpart, has antiangiogenic properties. These properties may explain, at least partly, the reported antineoplasic effect of experimental T. cruzi infection.     

Intracranial hemorrhage as initial presentation of biliary atresia: two cases report

Biliary atresia in infants occasionally presents as intracranial, nasal or gastrointestinal bleeding, instead of the classical triad of jaundice, acholia and choluria. We present two female infants aged four and two months, who were hospitalized with convulsive episode, cephalohematoma and drowsiness. Computed tomography findings were subdural hemorrhage in one patient and intraventricular and parenchymal bleeding in the other one. At admission they have history, clinical and laboratory signs of cholestasis of unknown etiology. The patient with subdural hemorrhage required surgical drainage. The other girl with intraventricular and parenchymal bleeding received vitamin K and no surgery. Biliary atresia was diagnosed and treated in both girls. At six months both had an adequate neurological outcome and required liver transplantation at one year old. Biliary atresia should be considered in all infants with sudden acute bleeding and cholestasis.     

Dendritic cells modifi cation during sublingual immunotherapy in children with allergic symptoms to house dust mites

Background

The importance of dendritic cells (DCs) in the initiation of the Th2-mediated inflammatory response to allergens is well known and more recently it has been proposed that DCs have a pivotal role in maintaining tolerance to allergens. The aim of this study was to investigate whether the success of sublingual immunotherapy (SLIT) in allergic asthma is mediated by the induction of changes of DCs functions.

Methods

Ten children with allergic asthma sensitive to house dust mite were studied before and after 12 months of SLIT. Immature DCs were derived from peripheral blood monocytes cultured for 6 days in presence of interleukin (IL)-4 and GM-CSF and stimulated with lipopolysaccharide for the last 24 hours to induce maturation.

Results

After 12 months of SLIT, mature DCs derived from SLIT-treated patients showed a statistically significant defect of CD86 up-regulation, an increase of IL-10, and a reduction of IL-12 production.

Conclusion

SLIT induces changes in DCs functions that might be responsible for an impairment of T cell activation or drive T cells towards a regulatory activity, thus restoring immune tolerance to allergens.     

Lower proportion of CD19+IL-10+ and CD19+CD24+CD27+ but not CD1d+CD5+CD19+CD24+CD27+ IL-10+ B cells in children with autoimmune thyroid diseases

Abstract

Introduction: As it is generally known, regulatory B cells (Bregs) control inflammation and autoimmunity. The significance of Bregs in the population of children with autoimmune thyroid diseases (AITD) still offers plenty of potential to explore. The aim of this study was to estimate the expression of Bregs (phenotype CD19⁺CD24⁺CD27⁺IL-10⁺, CD19⁺IL-10⁺, CD1d⁺CD5⁺CD19⁺IL-10⁺ and CD1d⁺CD5⁺CD19⁺CD24⁺CD27⁺) in a paediatric cohort with AITD and in health controls.

Materials and methods: A total of 100 blood samples were obtained from 53 paediatric patients with Graves’ disease (GD) (N?=?12 newly diagnosed, mean age 12.5?±?3.5 and N?=?17 during methimazole therapy, mean age 12.7?±?4.4), Hashimoto’s thyroiditis (HT) (N?=?10 newly diagnosed, mean age 13.3?±?2.9 and N?=?10 during L-thyroxine therapy, mean age 13.7?±?3.4) and compared with healthy controls (C) (N?=?15, mean age 13.1?±?3.1). The expressions of the immune cell populations were analysed by four-color flow cytometry using a FASC Canto II cytometer (BD Biosciences).

Results: There was a decreasing tendency in the number of lymphocytes B producing IL-10 (B10) cells among all B lymphocytes and more widely, also among all lymphocytes, in each study group, as compared to C. We reported a reduction in IL-10 production in Bregs with the expression of CD19⁺CD24⁺CD27⁺IL-10 and CD1d⁺CD5⁺CD19⁺IL-10⁺ in both untreated and treated AITD.

Conclusions: Our data demonstrate that the reduction in the number of Bregs with CD19⁺CD24⁺CD27⁺IL-10⁺ and CD19⁺IL-10⁺ expression could be responsible for breaking immune tolerance and for AITD development in children.     

Autosomal dominant Brody disease cosegregates with a chromosomal (2;7)(p11.2;p12.1) translocation in an Italian family

Brody disease is a rare muscle disorder characterized by exercise-induced impairment in muscle relaxation, due to a markedly reduced influx of calcium ions in the sarcoplasmic reticulum. A subset of autosomal recessive families harbour mutations in the ATP2A1 gene, encoding the fast-twitch skeletal muscle sarcoplasmic reticulum Ca(2+) ATPase (SERCA1). Rare autosomal dominant families have been described, in which ATP2A1 was excluded as the causative gene, further supporting genetic heterogeneity. We report four individuals from a three-generation Italian family with a clinical phenotype of Brody disease, in which linkage analysis excluded ATP2A1 as the responsible gene. The disease cosegregates in an autosomal dominant fashion with an apparently balanced constitutional chromosome translocation (2;7)(p11.2;p12.1), suggesting a causal relationship between the rearrangement and the phenotype. FISH analysis using YAC and PAC clones as probes refined the breakpoint regions to genomic segments of about 164 and 120 kb, respectively, providing a possible clue to pinpoint the location of a novel gene responsible for this rare muscle disorder.     

Reciprocal stimulation of gammadelta T cells and dendritic cells during the anti-mycobacterial immune response

Gammadelta T cells and dendritic cells (DC) are two distinct cell types of innate immunity that participate in early phases of immune response against Mycobacterium tuberculosis infection. Here we show that a close functional relationship exists between these cell populations. Using an in vitro coculture system, Vgamma1 T cells from Tcrb(-/- )mice were found to be activated by DC infected in vitro with BCG, as indicated by the elevated CD69 expression, IFN-gamma secretion and cytotoxic activity. This activation process was due to a non-cognate mechanism since it required neither cell to cell contact nor interaction between the TCR and a specific antigen, but was mediated by DC-derived IL-12. Reciprocally, Vgamma1 T cells provided a key cytokine, IFN-gamma, which increased IL-12 production by BCG-infected DC. Moreover, exposure of BCG-infected DC to Vgamma1 T cells conditioned the former to prime a significantly stronger anti-mycobacterial CD8 T cell response. Consequently, stimulation of gammadelta T cells and their non-cognate interaction with DC could be applied as an immune adjuvant strategy to optimize vaccine-induced CD8 T cell immunity.