Caenorhabditis elegans, un modèle utilisé pour le criblage de microbiotes fromagers à effet santé

International audienceCaenorhabditis elegans, un modèle utilisé pour le criblage de microbiotes fromagers à effet sant

Rapid Quantitative PCR Assay for the Detection of the Three Vaginal Pathogens Candida, Gardnerella and Atopobium as well as the Commensal Lactobacillus Genera

International audienceThe vaginal microbiota balance is quite fragile and susceptible to the development of vaginosis and candidiasis. The current diagnostic method for bacterial vaginosis relies on the evaluation of different bacterial morphotypes using the Nugent score. This method is only partially in correlation with a DNA sequencing-based diagnostic or Amsel criteria used by clinicians, suggesting the need for new molecular approaches dedicated to the diagnosis of BV. The objective of this study was to develop and validate a quantitative polymerase chain reaction (qPCR) assay for the specific and rapid detection of three vaginal pathogens, i.e. Candida, Gardnerella and Atopobium and the commensal Lactobacillus genera. For this purpose, four oligonucleotide primer pairs were designed and tested to obtain optimal amplification of the four target genera. The qPCR assay was also tested on the non-target genera and on human DNA. The designed primers allowed specific amplification of the target organisms in vitro and in clinical vaginal samples. The qPCR assay designed in this study is effective to specifically detect these genera in clinical samples as a molecular technique complementary to the Nugent score. It can be used in epidemiological studies for understanding the role of these pathogens and to follow their abundance in the microbiota in disease processes such as the development of vulvovaginal candidiasis and bacterial vaginosis

Lactobacillus rhamnosus Lcr35 as an effective treatment for preventing Candida albicans infection in the preclinical model Caenorhabditis elegans

International audienceIntroduction and aimsThe increased recurrence of Candida albicans infections is associated with greater resistance to antifungal drugs. This involves the establishment of alternative therapeutic protocols such as the use of probiotic microorganisms whose antifungal potential has already been demonstrated using preclinical models (cell cultures, laboratory animals) and clinical studies. Understanding the mechanisms of action of probiotic microorganisms has become a strategic need for the development of new therapeutics for humans. In this study, we investigated the prophylactic anti-Candida albicans properties of Lactobacillus rhamnosus Lcr35® using the in vivo Caenorhabditis elegans model. Materials and methodsFor this, we followed the survival of the nematode in the case of a fungal infection, prevented or not by the probiotic Lcr35®. This followed by a gene expression analysis. Also, we are interested in the localization of the DAF-16 transcription factor.Results, discussion and conclusionOn the top of having a pro-longevity activity in the nematode, Lcr35® protects the animal from the fungal infection even if the yeast is still detectable in its intestine. At the mechanistic level, we note the repression of genes of the p38 MAPK signaling pathway and genes involved in the antifungal response induced by Lcr35® suggesting that the pathogen no longer appears to be detected by the worm immune system. However, the DAF-16 / FOXO transcription factor, implicated in the longevity and antipathogenic response of C. elegans, is activated by Lcr35®. These results suggest that the probiotic strain acts by stimulating its host via DAF-16, but also by suppressing the virulence of the pathogen. However, for more precision, an exhaustive study of the C. elegans transcriptome will be carried out in order to decipher the mechanisms of action of Lcr35®

Lactobacillus rhamnosus Lcr35 en tant que traitement efficace contre l'infection à Candida albicans dans le modèle préclinique Caenorhabditis elegans

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Curative treatment of candidiasis by the live biotherapeutic microorganism Lactobacillus rhamnosus Lcr35® in the invertebrate model Caenorhabditis elegans: first mechanistic insights

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Lactobacillus rhamnosus Lcr35® as an effective treatment for preventing Candida albicans infection in the preclinical model Caenorhabditis elegans

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Curative Treatment of Candidiasis by the Live Biotherapeutic Microorganism Lactobacillus rhamnosus Lcr35 in the Invertebrate Model Caenorhabditis elegans: First Mechanistic Insights

International audienceThe resistance of Candida albicans to conventional drug treatments, as well as the recurrence phenomena due to dysbiosis caused by antifungal treatments, have highlighted the need to implement new therapeutic methodologies. The antifungal potential of live biotherapeutic products (LBP) has already been demonstrated using preclinical models (cell cultures, laboratory animals). Understanding their mechanisms of action is strategic for the development of new therapeutics for humans. In this study, we investigated the curative anti-C. albicans properties of Lactobacillus rhamnosus Lcr35 ® using the in vitro Caco-2 cell and the in vivo Caenorhabditis elegans models. We showed that Lcr35 ® does inhibit neither the growth (p = 0.603) nor the biofilm formation (p = 0.869) of C. albicans in vitro. Lcr35 ® protects the animal from the fungal infection (+225% of survival, p < 2 × 10-16) even if the yeast is detectable in its intestine. In contrast, the Lcr35 ® cell-free supernatant does not appear to have any antipathogenic effect. At the mechanistic level, the DAF-16/Forkhead Box O transcription factor is activated by Lcr35 ® and genes of the p38 MAP Kinase signaling pathway and genes involved in the antifungal response are upregulated in presence of Lcr35 ® after C. albicans infection. These results suggest that the LBM strain acts by stimulating its host via DAF-16 and the p38 MAPK pathway

Investigation into In Vitro and In Vivo Caenorhabditis elegans Models to Select Cheese Yeasts as Probiotic Candidates for their Preventive Effects against Salmonella Typhimurium

International audienceThe design of multiscale strategies integrating in vitro and in vivo models is necessary for the selection of new probiotics. In this regard, we developed a screening assay based on the investigation of the potential of yeasts from cheese as probiotics against the pathogen Salmonella Typhimurium UPsm1 (ST). Two yeasts isolated from raw-milk cheese (Saccharomyces cerevisiae 16, Sc16; Debaryomyces hansenii 25, Dh25), as well as S. cerevisiae subspecies boulardii (CNCM I-1079, Sb1079), were tested against ST by applying in vitro and in vivo tests. Adherence measurements to Caco-2 and HT29-MTX intestinal cells indicated that the two tested cheese yeasts presented a better adhesion than the probiotic Sb1079 as the control strain. Further, the Dh25 was the cheese yeast most likely to survive in the gastrointestinal tract. What is more, the modulation of the TransEpithelial Electrical Resistance (TEER) of differentiated Caco-2 cell monolayers showed the ability of Dh25 to delay the deleterious effects of ST. The influence of microorganisms on the in vivo model Caenorhabditis elegans was evaluated by measuring the longevity of the worm. This in vivo approach revealed that this yeast increased the worm's lifespan and protected it against ST infection, confirming that this in vivo model can be useful for screening probiotic cheese yeasts

Lactobacillus rhamnosus Lcr35 as an effective treatment for preventing Candida albicans infection in the invertebrate model Caenorhabditis elegans: First mechanistic insights

International audienceThe increased recurrence of Candida albicans infections is associated with greater resistance to antifungal drugs. This involves the establishment of alternative therapeutic protocols , such as probiotic microorganisms whose antifungal potential has already been demonstrated using preclinical models (cell cultures, laboratory animals). Understanding the mechanisms of action of probiotic microorganisms has become a strategic need for the development of new therapeutics for humans. In this study, we investigated the prophylactic anti-C. albicans properties of Lactobacillus rhamnosus Lcr35 ® using the in vitro Caco-2 cell model and the in vivo Caenorhabditis elegans model. In Caco-2 cells, we showed that the strain Lcr35 ® significantly inhibited the growth (~2 log CFU.mL-1) and adhesion (150 to 6,300 times less) of the pathogen. Moreover, in addition to having a pro-longevity activity in the nematode (+42.9%, p = 3.56.10 −6), Lcr35 ® protects the animal from the fungal infection (+267% of survival, p < 2.10 −16) even if the yeast is still detectable in its intestine. At the mechanistic level, we noticed the repression of genes of the p38 MAPK signalling pathway and genes involved in the antifungal response induced by Lcr35 ® , suggesting that the pathogen no longer appears to be detected by the worm immune system. However, the DAF-16/ FOXO transcription factor, implicated in the longevity and antipathogenic response of C. ele-gans, is activated by Lcr35 ®. These results suggest that the probiotic strain acts by stimulating its host via DAF-16 but also by suppressing the virulence of the pathogen