Role of lactoferrin and its receptors on biliary epithelium

Human lactoferrin is an iron-binding glycoprotein present at high concentrations in breast milk and colostrum. It is produced by many exocrine glands and widely distributed in a variety of body fluids. This protein has antimicrobial, immunomodulatory, antioxidant, and anticancer properties. Two important hLf receptors have been identified: LDL receptor related protein (LRP1), a low specificity receptor, and intelectin-1 (ITLN1), a high specificity receptor. No data are present on the role of hLf on the biliary epithelium. Our aims have been to evaluate the expression of Lf and its receptors in human and murine cholangiocytes and its effect on proliferation. Immunohistochemistry and immunofluorescence (IF) were conducted on human healthy and primary biliary cholangitis (PBC) liver samples as well as on liver samples obtained from normal and bile duct ligated (BDL) mice to evaluate the expression of Lf, LRP1 and ITLN1. Cell proliferation in vitro studies were performed on human cholangiocyte cell lines via 3-(4,5-dimetiltiazol-2-il)-2,5-diphenyltetrazolium assay as well as IF to evaluate proliferating cell nuclear antigen (PCNA) expression. Our results show that mouse and human cholangiocytes express Lf, LRP1 and ITLN1, at higher extent in cholangiocytes from BDL and PBC samples. Furthermore, the in vitro addition of bovine Lf (bLf) has a proliferative effect on human cholangiocyte cell line. The results support a proliferative role of hLf on the biliary epithelium; this pro-proliferative effect of hLf and bLf on cholangiocytes could be particularly relevant in human cholangiopathies such as PBC, characterized by cholangiocyte death and ductopenia.     

Ectoderm removal prevents cutaneous nerve formation and perturbs sensory axon growth in the chick hindlimb

Target tissues are thought to provide important cues for growing axons, yet there is little direct evidence that they are essential for axonal pathfinding. Here we examined whether target ectoderm is necessary for the formation of cutaneous nerves, and for the normal growth and guidance of cutaneous axons as they first enter the limb plexus. To do this, we removed a patch of ectoderm from the chick hindlimb at various times during early axon outgrowth. We find there is a critical period when cutaneous nerve formation requires target ectoderm. When the ectoderm is absent during this time, axons progress into the limb more slowly and, although a few sensory axons occasionally diverge a short distance from the plexus, they do not form a discrete nerve that travels to the skin. A few days later, when the nerve pattern is mature, axons normally destined for the 'deprived' cutaneous nerve are not segregated appropriately within the plexus. Some cutaneous axons are instead misdirected along an inappropriate cutaneous nerve, while others have seemingly failed to reach their correct target, or a suitable alternative, and died. These results demonstrate that the target ectoderm is necessary for normal sensory axon growth and guidance in the hindlimb.     

Surgical mask to prevent influenza transmission in households: a cluster randomized trial

Background

Facemasks and respirators have been stockpiled during pandemic preparedness. However, data on their effectiveness for limiting transmission are scarce. We evaluated the effectiveness of facemask use by index cases for limiting influenza transmission by large droplets produced during coughing in households.

Methodology and Principal Findings

A cluster randomized intervention trial was conducted in France during the 2008–2009 influenza season. Households were recruited during a medical visit of a household member with a positive rapid influenza A test and symptoms lasting less than 48 hours. Households were randomized either to the mask or control group for 7 days. In the intervention arm, the index case had to wear a surgical mask from the medical visit and for a period of 5 days. The trial was initially intended to include 372 households but was prematurely interrupted after the inclusion of 105 households (306 contacts) following the advice of an independent steering committee. We used generalized estimating equations to test the association between the intervention and the proportion of household contacts who developed an influenza-like illness during the 7 days following the inclusion. Influenza-like illness was reported in 24/148 (16.2%) of the contacts in the intervention arm and in 25/158 (15.8%) of the contacts in the control arm and the difference between arms was 0.40% (95%CI: −10% to 11%, P = 1.00). We observed a good adherence to the intervention. In various sensitivity analyses, we did not identify any trend in the results suggesting effectiveness of facemasks.

Conclusion

This study should be interpreted with caution since the lack of statistical power prevents us to draw formal conclusion regarding effectiveness of facemasks in the context of a seasonal epidemic.

Trial Registration

clinicaltrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00774774","term_id":"NCT00774774"}}NCT00774774     

Mitochondrial dysfunction and the inflammatory response

Inflammation has been linked to multiple degenerative and acute diseases as well as the aging process. Moreover, mitochondrial alterations play a central role in these processes. Mitochondria have an important role in pro-inflammatory signaling; similarly, pro-inflammatory mediators may also alter mitochondrial function. Both of these processes increase mitochondrial oxidative stress, promoting a vicious inflammatory cycle. Additionally, damage-associated molecular patterns derived from mitochondria could contribute to inflammasome formation and caspase-1 activation, while alterations in mitochondrial autophagy may cause inflammation. Strategies aimed at controlling excessive oxidative stress within mitochondria may represent both preventive and therapeutic interventions in inflammation.     

Expression levels and subcellular localization of Bcy1p in Candida albicans mutant strains devoid of one BCY1 allele results in a defective morphogenetic behavior

We investigated expression, functionality and subcellular localization of C. albicans Bcy1p, the PKA regulatory subunit, in mutant strains having one BCY1 allele fused to a green fluorescent protein (GFP). DE-52 column chromatography of soluble extracts of yeast cells from strains bearing one BCY1 allele (fused or not to GFP) showed co-elution of Bcy1p and Bcy1p-GFP with phosphotransferase activity, suggesting that interaction between regulatory and catalytic subunits was not impaired by the GFP tag. Subcellular localization of Bcy1p-GFP supports our previous hypothesis on the nuclear localization of the regulatory subunit, which can thus tether the PKA catalytic subunit to the nucleus. Protein modeling of CaBcy1p, showed that the fusion of the GFP tag to Bcy1p C-terminus did not significantly disturb its proper folding. Bcy1p levels in mutant strains having one or both BCY1 alleles, led us to establish a direct correlation between the amount of protein and the number of alleles, indicating that deletion of one BCY1 allele is not fully compensated by overexpression of the other. The morphogenetic behavior of several C. albicans mutant strains bearing one or both BCY1 alleles, in a wild-type and in a TPK2 null genetic background, was assessed in N-acetylglucosamine (GlcNAc) liquid medium at 37 degrees C. Strains with one BCY1 allele tagged or not, behaved similarly, displaying pseudohyphae and true hyphae. In contrast, hyphal morphology was almost exclusive in strains having both BCY1 alleles, irrespective of the GFP insertion. It can be inferred that a tight regulation of PKA activity is needed for hyphal growth.     

Novel approaches to monitor bacterial gene expression in infected tissue and host

Elucidating the complex and dynamic host-microbe interactions during infection requires, among other things, detailed knowledge of microbial gene expression in vivo. Recently, advances in fluorescence and bioluminescence detection techniques, as well as recombinase-based in vivo expression technology, have rendered monitoring virulence gene expression in vivo a feasible task. These techniques have been adapted by several laboratories to study the spatial and temporal patterns of virulence gene expression by organisms such as Salmonella typhimurium, Listeria monocytogenes, Yersinia entercolitica and Vibrio cholerae during infection of tissue culture or animal models of infection.