Lactobacillus paracasei modulates the immune system of Galleria mellonella and protects against Candida albicans infection

Abstract

Probiotics have been described as a potential strategy to control opportunistic infections due to their ability to stimulate the immune system. Using the non-vertebrate model host Galleria mellonella, we evaluated whether clinical isolates of Lactobacillus spp. are able to provide protection against Candida albicans infection. Among different strains of Lactobacillus paracasei, Lactobacillus rhamnosus and Lactobacillus fermentum, we verified that L. paracasei 28.4 strain had the greatest ability to prolong the survival of larvae infected with a lethal dose of C. albicans. We found that the injection of 107 cells/larvae of L. paracasei into G. mellonella larvae infected by C. albicans increased the survival of these insects compared to the control group (P = 0.0001). After that, we investigated the immune mechanisms involved in the protection against C. albicans infection, evaluating the number of hemocytes and the gene expression of antifungal peptides. We found that L. paracasei increased the hemocyte quantity (2.38 x 106 cells/mL) in relation to the control group (1.29 x 106 cells/mL), indicating that this strain is capable of raising the number of circulating hemocytes into the G. mellonella hemolymph. Further, we found that L. paracasei 28.4 upregulated genes that encode the antifungal peptides galiomicin and gallerymicin. In relation to the control group, L. paracasei 28.4 increased gene expression of galiomicin by 6.67-fold and 17.29-fold for gallerymicin. Finally, we verified that the prophylactic provision of probiotic led to a significant reduction of the number of fungal cells in G. mellonella hemolymph. In conclusion, L. paracasei 28.4 can modulate the immune system of G. mellonella and protect against candidiasis.

Development of antimicrobial gummy candies with addition of bovine colostrum, essential oils and probiotics

“…In fermented with LUHS135, BC samples enterobacteria, E. coli and mould/yeast counts were reduced by 46.6%, 49.3% and 47.1%, respectively. L. paracasei can modulate the immune system and protect against candidiasis (Rossoni et al, 2017). In dried BC samples, LAB count ranged from 7.82 log 10 CFU g À1 (in the lyophilised and fermented with LUHS135 BC powder) to 6.00 log 10 CFU g À1 (in the vacuum-dried nonfermented BC powder).…”

“…LAB are generally believed to play a positive role in maintaining good health and immune system in humans (Satpute et al, 2016). L. paracasei can modulate the immune system and protect against candidiasis (Rossoni et al, 2017). Antimicrobial activity of the Lactobacillus plantarum strain against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, Salmonella enterica and Candida albicans has been demonstrated by Li et al (2016).…”

Galleria mellonella as a consolidated in vivo model hosts: New developments in antibacterial strategies and novel drug testing

“…Usually, in most experiments using larvae of G. mellonella, infection is induced by an intra hemocoelic injection of a titrated bacterial inoculum through the last left proleg. The response to infection can be assessed by different parameters: mortality, melanization, larvae mobility, cocoon formation, quantification of hemocytes and microorganisms in the hemolymph, alteration in gene expression and variations in the proteome [105][106][107]. Although the infection method and the scoring parameters used in microbial infection studies are very similar, there are numerous experimental variations: preparation or quantity of inoculum injected, source and management of larvae, experimental conditions or subjective interpretation of scoring parameters (morbidity or mortality).…”

Potential anticancer effects of cell wall protein fractions from Lactobacillus paracasei on human intestinal Caco‐2 cell line

“…paracasei X12 can block HT‐29 cell cycle and exhibit effective anticancer activities by modulation of mammalian target of rapamycin (mTOR) signalling pathway. Lactobacillus paracasei has shown to prevent Candida albicans infection by modulating the immune system (Rossoni et al ). In addition, it has been demonstrated that L. casei extract induced extrinsic apoptosis pathway in CT26 and HT29 cells by induction of TNF‐related apoptosis‐inducing ligand (TRAIL) (Tiptiri‐Kourpeti et al ).…”