PLoS ONE

Lyme disease is a multisystemic disorder caused by B. burgdorferi sl. The molecular basis for specific organ involvement is poorly understood. The skin plays a central role in the development of Lyme disease as the entry site of B. burgdorferi in which specific clones are selected before dissemination. We compared the skin inflammatory response (antimicrobial peptides, cytokines and chemokines) elicited by spirochete populations recovered from patients presenting different clinical manifestations. Remarkably, these spirochete populations induced different inflammatory profiles in the skin of C3H/HeN mice. As spirochete population transmitted into the host skin is heterogeneous, we isolated one bacterial clone from a population recovered from a patient with neuroborreliosis and compared its virulence to the parental population. This clone elicited a strong cutaneous inflammatory response characterized by MCP-1, IL-6 and antimicrobial peptides induction. Mass spectrometry of this clone revealed 110 overexpressed proteins when compared with the parental population. We further focused on the expression of nine bacterial surface proteins. bb0347 coding for a protein that interacts with host fibronectin, allowing bacterial adhesion to vascular endothelium and extracellular matrix, was found to be induced in host skin with another gene bb0213 coding for a hypothetical protein. These findings demonstrate the heterogeneity of the B. burgdorferi ss population and the complexity of the interaction involved early in the skin

Synthese et utilisation de marqueurs irreversibles: application a la caracterisation des sites de liaison des cholinesterases

SIGLEINIST T 74398 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Controlled ingestion of kaolinite (5%) modulates enteric nitrergic innervation in rats

International audienceWe have previously shown that kaolinite slowed down gastric emptying and intesti- nal transit and induced changes in enteric mechanical activities. As gastric emptying and intestinal transit have been shown to be regulated by nitric oxide (NO), the effect of an imposed ingestion of kaolinite on enteric nitrergic innervation was determined. Kaolinite has also been shown to increase plasmatic levels of leptin. Therefore, the responses of enteric neurons in the presence of leptin after kaolinite ingestion were determined, and a possible role of nitrergic neurons was evaluated in rats using organ bath technique. Our results showed that kaolinite modulates activities of enteric nerves at 14 days of ingestion. Exogenous L-NNA produced a decrease in nerve stimulation (NS)-induced relaxation in both jejunum and colon of control groups. At 14 days of kaolinite ingestion, this effect of L-NNA was significantly reduced only in the jejunum. Although L-NNA did not affect NS-induced contraction in jejunum and colon of control animals, it increased the amplitude of the NS- induced contraction in the colon of rats at 14 days of kaolinite ingestion. Leptin inhibitory effects on ENS in the jejunum were also altered at 14 days of ingestion. These differences were masked in the presence of L-NNA. Our data give evidence that changes in mechanical activities induced by kaolinite might be due to alterations in inhibitory (nitrergic and/or other) innervation at 14 days of kaolinite ingestion and to modifications of leptin effects on the responses to intramural nerve stimulation

Skin Interface, a Key Player for Borrelia Multiplication and Persistence in Lyme Borreliosis

International audienceThe skin plays a key role in vector-borne diseases because it is the site where the arthropod coinoculates pathogens and its saliva. Lyme borreliosis, particularly well investigated in this context, is a multisystemic infectious disease caused by Borrelia burgdorferi sensu lato and transmitted by the hard tick Ixodes. Numerous in vitro studies were conducted to better understand the role of specific skin cells and tick saliva in host defense, vector feeding, and pathogen transmission. The skin was also evidenced in various animal models as the site of bacterial multiplication and persistence. We present the achievements in this field as well as the gaps that impede comprehensive knowledge of the disease pathophysiology and the development of efficient diagnostic tools and vaccines in humans. Copyright © 2020 Elsevier Ltd. All rights reserved

Bifunctional bispidine derivatives for copper-64 labelling and positron emission tomography

International audienc

Discovery and targeted proteomics on cutaneous biopsies: a promising work toward an early diagnosis of Lyme disease.

Lyme disease is the most important vector-borne disease in the Northern hemisphere and represents a major public health challenge with insufficient means of reliable diagnosis. Skin is rarely investigated in proteomics but constitutes in the case of Lyme disease the key interface where the pathogens can enter, persist, and multiply. Therefore, we investigated proteomics on skin samples to detect Borrelia proteins directly in cutaneous biopsies in a robust and specific way. We first set up a discovery gel prefractionation-LC-MS/MS approach on a murine model infected by Borrelia burgdorferi sensu stricto that allowed the identification of 25 Borrelia proteins among more than 1300 mouse proteins. Then we developed a targeted gel prefractionation-LC-selected reaction monitoring (SRM) assay to detect 9/33 Borrelia proteins/peptides in mouse skin tissue samples using heavy labeled synthetic peptides. We successfully transferred this assay from the mouse model to human skin biopsies (naturally infected by Borrelia), and we were able to detect two Borrelia proteins: OspC and flagellin. Considering the extreme variability of OspC, we developed an extended SRM assay to target a large set of variants. This assay afforded the detection of nine peptides belonging to either OspC or flagellin in human skin biopsies. We further shortened the sample preparation and showed that Borrelia is detectable in mouse and human skin biopsies by directly using a liquid digestion followed by LC-SRM analysis without any prefractionation. This study thus shows that a targeted SRM approach is a promising tool for the early direct diagnosis of Lyme disease with high sensitivity (<10 fmol of OspC/mg of human skin biopsy)

Proteomic analysis of three Borrelia burgdorferi sensu lato native species and disseminating clones

Lyme borreliosis is the most important vector-borne disease in the Northern hemisphere. It is caused by Borrelia burgdorferi sensu lato bacteria transmitted to humans by the bite of hard ticks, Ixodes spp. Although antibiotic treatments are efficient in the early stage of the infection, a significant number of patients develop disseminated manifestations (articular, neurological and cutaneous) due to unnoticed or absence of erythema migrans, or to inappropriate treatment. Vaccine could be an efficient approach to decrease Lyme disease incidence. We have developed a proteomic approach based on a Ge-LC-MS/MS strategy to identify new vaccine candidates. We analyzed a disseminating clone and the associated wild type strain for each major pathogenic Borrelia species: B. burgdorferi sensu stricto, B. garinii and B. afzelii. We identified specific proteins and common proteins to the disseminating clones of the three main species. In parallel, we used a spectral counting strategy to identify up-regulated proteins common to the clones. Finally, 40 proteins were found that could potentially be involved in bacterial virulence and of interest in the development of a new vaccine. We selected the three proteins specifically detected in the disseminating clones of the three Borrelia species and checked by RT-PCR whether they are expressed in mouse skin upon B. burgdorferi ss inoculation. Interestingly, BB0566 appears as a potential vaccine candidate. This article is protected by copyright. All rights reserved

Phenotypic adaptation of Pseudomonas aeruginosa in the presence of siderophoreantibiotic conjugates during epithelial cell infection

International audienc