title: 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.
authors.affiliation: Department of Biosciences and Oral Diagnosis, Univ Estadual Paulista/UNESP, São José dos Campos, São Paulo, Brazil.|Division of Infectious Diseases, Rhode Island Hospital, Alpert Medical School of Brown University, Providence, Rhode Island, United States of America.
authors.forename: Rodnei Dennis
authors.initials: RD
authors.lastname: Rossoni
authors.affiliation: Division of Infectious Diseases, Rhode Island Hospital, Alpert Medical School of Brown University, Providence, Rhode Island, United States of America.
authors.forename: Beth Burgwyn
authors.initials: BB
authors.lastname: Fuchs
authors.affiliation: Department of Biosciences and Oral Diagnosis, Univ Estadual Paulista/UNESP, São José dos Campos, São Paulo, Brazil.
authors.forename: Patrícia Pimentel
authors.initials: PP
authors.lastname: de Barros
authors.affiliation: Department of Biosciences and Oral Diagnosis, Univ Estadual Paulista/UNESP, São José dos Campos, São Paulo, Brazil.
authors.forename: Marisol Dos Santos
authors.initials: MD
authors.lastname: Velloso
authors.affiliation: Department of Biosciences and Oral Diagnosis, Univ Estadual Paulista/UNESP, São José dos Campos, São Paulo, Brazil.
authors.forename: Antonio Olavo Cardoso
authors.initials: AO
authors.lastname: Jorge
authors.affiliation: Department of Biosciences and Oral Diagnosis, Univ Estadual Paulista/UNESP, São José dos Campos, São Paulo, Brazil.
authors.forename: Juliana Campos
authors.initials: JC
authors.lastname: Junqueira
authors.affiliation: Division of Infectious Diseases, Rhode Island Hospital, Alpert Medical School of Brown University, Providence, Rhode Island, United States of America.
authors.forename: Eleftherios
authors.initials: E
authors.lastname: Mylonakis
mesh_terms: D000818:Animals; D002176:Candida albicans / Q000276:immunology*; D015169:Colony Count, Microbial; D060467:Disease Resistance / Q000276:immunology*; D005786:Gene Expression Regulation; D006434:Hemocytes; D006458:Hemolymph; D054884:Host-Pathogen Interactions / Q000235:genetics / Q000276:immunology; D006801:Humans; D056747:Immunomodulation; D000069980:Lacticaseibacillus paracasei / Q000502:physiology*; D007814:Larva / Q000382:microbiology; D009036:Moths / Q000235:genetics / Q000276:immunology* / Q000382:microbiology*; D019936:Probiotics