20 research outputs found
Activin A induces dendritic cell migration through the polarized release of CXC chemokine ligands 12 and 14
Activin A is a dimeric protein, member of
the transforming growth factor (TGF)–
family that plays a crucial role in wound
repair and in fetal tolerance. Emerging
evidence also proposes activin Aas a key
mediator in inflammation. This study reports
that activin A induces the directional
migration of immature myeloid dendritic
cells (iDCs) through the activation
of ALK4 and ActRIIA receptor chains.
Conversely, activin A was not active on
plasmacytoid dendritic cells (DCs) or mature
myeloid DCs. iDC migration to activin
A was phosphatidylinositol 3-kinase
–dependent, Bordetella pertussis toxin–
and cycloheximide-sensitive, and was
inhibited by M3, a viral-encoded chemokinebinding
protein. In a real-time video
microscopy-based migration assay, activin
A induced polarization of iDCs, but
not migration. These characteristics
clearly differentiated the chemotactic activities
of activin A from TGF- and classic
chemokines. By the use of combined
pharmacologic and low-density microarray
analysis, it was possible to define that
activin-A–induced migration depends on
the selective and polarized release of
2 chemokines, namely CXC chemokine
ligands 12 and 14. This study extends the
proinflammatory role of activin A to DC
recruitment and provides a cautionary
message about the reliability of the in
vitro chemotaxis assays in discriminating
direct versus indirect chemotactic
agonists
Antimicrobial Resistance of Escherichia coli in Dairy Calves: A 15-Year Retrospective Analysis and Comparison of Treated and Untreated Animals
The health problem of antimicrobial resistance (AMR) involves several species. AMR surveillance is essential to identify its development and design control strategies; however, available data are still limited in some contexts. The AMR profiles of 2612 E. coli strains isolated over a period of 15 years (2002–2016) from calf enteric cases were analyzed to determine the presence of resistance and their temporal dynamics. Furthermore, the AMR profiles and the presence of the major virulence genes of 505 E. coli strains isolated from 1-week- and 2-week-old calves, 406 treated with antimicrobials and 99 untreated, were analyzed and compared to investigate the potential effects of treatment on AMR and strain pathogenicity. Resistance to tetracycline (90.70%) was the most common, followed by resistance to sulfamethoxazole/trimethoprim (77.70%) and flumequine (72.10%). The significantly higher percentage of AMR and virulence gene expression recorded in treated calves, combined with the statistically higher resistance to sulfamethoxazole/trimethoprim in E. coli with K99, corroborates the notion of resistance being induced by the frequent use of antimicrobials, leading to treatments potentially becoming ineffective. The significantly higher resistance to amoxicillin/clavulanic acid, enrofloxacin, and florfenicol in isolates from 1-week-old calves suggests the role of the environment as a source of contamination that should be investigated further
Selective activation of human dendritic cells by OM-85 through a NF-kB and MAPK dependent pathway.
OM-85 (Broncho-Vaxom®, Broncho-Munal®, Ommunal®, Paxoral®, Vaxoral®), a product made of the water soluble fractions of 21 inactivated bacterial strain patterns responsible for respiratory tract infections, is used for the prevention of recurrent upper respiratory tract infections and acute exacerbations in chronic obstructive pulmonary disease patients. OM-85 is able to potentiate both innate and adaptive immune responses. However, the molecular mechanisms responsible for OM-85 activation are still largely unknown. Purpose of this study was to investigate the impact of OM-85 stimulation on human dendritic cell functions. We show that OM-85 selectively induced NF-kB and MAPK activation in human DC with no detectable action on the interferon regulatory factor (IRF) pathway. As a consequence, chemokines (i.e. CXCL8, CXCL6, CCL3, CCL20, CCL22) and B-cell activating cytokines (i.e. IL-6, BAFF and IL-10) were strongly upregulated. OM-85 also synergized with the action of classical pro-inflammatory stimuli used at suboptimal concentrations. Peripheral blood mononuclear cells from patients with COPD, a pathological condition often associated with altered PRR expression pattern, fully retained the capability to respond to OM-85. These results provide new insights on the molecular mechanisms of OM-85 activation of the immune response and strengthen the rational for its use in clinical settings
ESBL/AmpC-Producing Escherichia coli in Wild Boar: Epidemiology and Risk Factors
The complex health problem of antimicrobial resistance (AMR) involves many host species, numerous bacteria and several routes of transmission. Extended-spectrum β-lactamase and AmpC (ESBL/AmpC)-producing Escherichia coli are among the most important strains. Moreover, wildlife hosts are of interest as they are likely antibiotics free and are assumed as environmental indicators of AMR contamination. Particularly, wild boar (Sus scrofa) deserves attention because of its increased population densities, with consequent health risks at the wildlife–domestic–human interface, and the limited data available on AMR. Here, 1504 wild boar fecal samples were microbiologically and molecularly analyzed to investigate ESBL/AmpC-producing E. coli and, through generalized linear models, the effects of host-related factors and of human population density on their spread. A prevalence of 15.96% of ESBL/AmpC-producing E. coli, supported by blaCTX-M (12.3%), blaTEM (6.98%), blaCMY (0.86%) and blaSHV (0.47%) gene detection, emerged. Young animals were more colonized by ESBL/AmpC strains than older subjects, as observed in domestic animals. Increased human population density leads to increased blaTEM prevalence in wild boar, suggesting that spatial overlap may favor this transmission. Our results show a high level of AMR contamination in the study area that should be further investigated. However, a role of wild boar as a maintenance host of AMR strains emerged
Angiostatic and chemotactic activities of the CXC chemokine CXCL4L1 (platelet factor-4 variant) are mediated by CXCR3
We investigated possible cellular receptors for the human CXC chemokine platelet factor-4 variant/CXCL4L1, a potent inhibitor of angiogenesis. We found that CXCL4L1 has lower affinity for heparin and chondroitin sulfate-E than platelet factor-4 (CXCL4) and showed that CXCL10 and CXCL4L1 could displace each other on microvascular endothelial cells. Labeled CXCL4L1 also bound to CXCR3A- and CXCR3B-transfectants and was displaced by CXCL4L1, CXCL4, and CXCL10. The CXCL4L1 anti-angiogenic activity was blocked by anti-CXCR3 antibodies (Abs) in the Matrigel and cornea micropocket assays. CXCL4L1 application in CXCR3−/− or in wild-type mice treated with neutralizing anti-CXCR3 Abs, resulted in reduced inhibitory activity of CXCL4L1 on tumor growth and vascularization of Lewis lung carcinoma. Furthermore, CXCL4L1 and CXCL4 chemoattracted activated T cells, human natural killer cells, and human immature dendritic cells (DCs). Migration of DCs toward CXCL4 and CXCL4L1 was desensitized by preincubation with CXCL10 and CXCL11, inhibited by pertussis toxin, and neutralized by anti-CXCR3 Abs. Chemotaxis of T cells, natural killer cells, and DCs is likely to contribute to the antitumoral action. However, the in vivo data indicate that the angiostatic property of CXCL4L1 is equally important in retarding tumor growth. Thus, both CXCR3A and CXCR3B are implicated in the chemotactic and vascular effects of CXCL4L1
Activation of PBMC and MoDC from COPD patients and healthy subjects by OM-85.
<p><b>A</b>) PBMC and <b>B</b>) MoDC (both 10<sup>6</sup>/ml) were stimulated as indicated in the presence or absence of 500 U/ml IFNγ or 100 ng/ml TNF-α. After 24 hours, supernatants were collected and analyzed by ELISA. Figure shows the results of healthy donors (open histograms) compared to COPD patients (black histograms). *P<0.05 by paired Student's <i>t</i> test.</p
Induction of selected cytokines and chemokines by OM-85 in MoDC.
<p><b>A</b>) MoDC (10<sup>6</sup>/ml) were stimulated with OM-85 as indicated and with 100 ng/ml LPS (IL-6, BAFF, CCL2, CXCL8 and CXCL6) or 10 ng/ml LPS (CCL3, CCL20 and CCL22) as a positive control. After 24 hours, supernatants were collected and analyzed by ELISA. Ut = untreated. *P<0.05 and **P<0.01 by Dunnett's Multiple Comparison Test. <b>B</b>) Supernatants of MoDC stimulated with OM-85 induce a G-protein-dependent migration of PMN. As a comparison, migration of PMN was elicited with unstimulated supernatants+CXCL8 and PMA. As expected, migration to CXCL8 was inhibited by both 10 nM M3 and 750 ng/ml, <i>Pertussis toxin</i> (P.Tox) while migration to PMA was not. Results are expressed as chemotactic index over migration to supernatants of unstimulated MoDC and represent means+/−SD of three independent Boyden chamber experiments. *P value<0.05 and ** P value<0.01 by Dunnett's Multiple Comparison Test.</p