The spread of multidrug-resistant bacteria, such as the skin commensal Staphylococcus aureus, is a worldwide health challenge; new methods to counteract opportunistic pathogen growth and virulence are urgent. We compared the activity of Lacticaseibacillus rhamnosus LR06 (DSM 21981) and Lactobacillus johnsonii LJO02 (DSM 33828) cell-free supernatants (CFSs) produced in the conventional animal derivative-based MRS medium and an innovative animal derivative-free broth (TIL) versus the MDR S. aureus (ATCC 43300). CFS influence was assessed towards the viability, metabolic activity, and ability to form biofilm of the MDR strain through optical density, alamarBlue assay, and crystal violet staining; their content in short-chain fatty acids, lactic acid, and proteins was analysed via high-resolution mass spectrometry and gas chromatography. All CFSs reduce viable and metabolically active S. aureus, being TIL more efficient compared to MRS in stimulating lactic acid bacteria metabolism and decreasing S. aureus biofilm formation. Particularly, the CFS from LJO02 grown in TIL has the best efficacy, revealing a high amount of lactic acid and 59 peculiar proteins; its effectiveness is partially maintained upon trypsin and proteinase K treatments, but not by pepsin and pH basification. Therefore, antagonistic CFSs may represent a strategic prevention approach, with bacteriotherapeutic and bio-repair potential.
Oral lichen planus (OLP) is a T cell-mediated chronic inflammatory disorder with multifactorial aetiology and malignant transformation potential. Despite the treatments so far identified, new tailored and safe specific measures are needed. Recently, human microbiota imbalance has been linked to several immune-mediated diseases, opening new therapeutic perspectives for probiotics; besides their ability to directly interact with the host microbiota, they also display a strain-specific immune-modulatory effect. Thus, this non-systematic review aims to elucidate the molecular pathways underlying probiotic activity, mainly those of Lactobacilli and Bifidobacteria and their metabolites in OLP pathogenesis and malignant transformation, focusing on the most recent in vitro and in vivo research evidence. Findings related to their activity in other immune-mediated diseases are here included, suggesting a probiotic translational use in OLP. Probiotics show immune-modulatory and microbiota-balancing activities; they protect the host from pathogens, hamper an excessive effector T cell response, reduce nuclear factor-kappa B (NF-kB) signalling and basal keratinocytes abnormal apoptosis, shifting the mucosal response towards the production of anti-inflammatory cytokines, thus preventing uncontrolled damage. Therefore, probiotics could be a highly encouraging prevention and immunotherapeutic approach for a safer and more sustainable OLP management.
The incidence of malignant melanoma is steadily rising. Resistance to therapy in malignant melanoma is linked to an increase of melanoma cell heterogeneity especially in regard to the response to pro-inflammatory signals from the tumor microenvironment (TME). For different tumor entities an infiltration of mast cells (MCs) into the TME has been reported, but their impact on tumor progression has been discussed controversially. We recently demonstrated that in melanoma MCs accumulate, especially in areas of immune regression. Since MCs are very plastic and can secrete various mediators, we are currently investigating how different stimuli activate MCs and how this affects the immune control of melanoma. MC precursors were isolated from murine femur and matured in medium containing IL-3 and stem cell factor. Mature bone-marrow derived MCs (BMMCs) were then stimulated with a variety of stimuli, including IL-33 and TLR-ligands. Changes in cytokine production was analyzed by ELISA. Through stimulation with IL-33, BMMCs were activated to produce a wide range of cytokines, as detected in the supernatant. This activation also impacted the transcription of genes, as shown by RNA-Sequencing. This effect can be intercepted through the application of resveratrol. In combinations with other stimuli both antagonistic and synergistic effects could be identified, indicating a directed development of MCs upon intervention. Among the highest concentrations of cytokines detected in the supernatant were chemokines that play a crucial role in the recruitment of immune cells, such as CCL3 and CCL22. In vivo experiments of wild type mice show that IL-33 does not impact tumor size, however, alters the immune cell recruitment to the tumor and the infiltration into the tumor. To investigate the impact of stimulated MCs on tumor progression and immune cell recruitment, in vivo studies with mastcell deficient Mctp5-Cre RDTA mice are performed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.